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5b497af4 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
51580e79 | 2 | /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com |
969bf05e | 3 | * Copyright (c) 2016 Facebook |
fd978bf7 | 4 | * Copyright (c) 2018 Covalent IO, Inc. http://covalent.io |
51580e79 | 5 | */ |
838e9690 | 6 | #include <uapi/linux/btf.h> |
51580e79 AS |
7 | #include <linux/kernel.h> |
8 | #include <linux/types.h> | |
9 | #include <linux/slab.h> | |
10 | #include <linux/bpf.h> | |
838e9690 | 11 | #include <linux/btf.h> |
58e2af8b | 12 | #include <linux/bpf_verifier.h> |
51580e79 AS |
13 | #include <linux/filter.h> |
14 | #include <net/netlink.h> | |
15 | #include <linux/file.h> | |
16 | #include <linux/vmalloc.h> | |
ebb676da | 17 | #include <linux/stringify.h> |
cc8b0b92 AS |
18 | #include <linux/bsearch.h> |
19 | #include <linux/sort.h> | |
c195651e | 20 | #include <linux/perf_event.h> |
d9762e84 | 21 | #include <linux/ctype.h> |
6ba43b76 | 22 | #include <linux/error-injection.h> |
9e4e01df | 23 | #include <linux/bpf_lsm.h> |
1e6c62a8 | 24 | #include <linux/btf_ids.h> |
51580e79 | 25 | |
f4ac7e0b JK |
26 | #include "disasm.h" |
27 | ||
00176a34 | 28 | static const struct bpf_verifier_ops * const bpf_verifier_ops[] = { |
91cc1a99 | 29 | #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ |
00176a34 JK |
30 | [_id] = & _name ## _verifier_ops, |
31 | #define BPF_MAP_TYPE(_id, _ops) | |
f2e10bff | 32 | #define BPF_LINK_TYPE(_id, _name) |
00176a34 JK |
33 | #include <linux/bpf_types.h> |
34 | #undef BPF_PROG_TYPE | |
35 | #undef BPF_MAP_TYPE | |
f2e10bff | 36 | #undef BPF_LINK_TYPE |
00176a34 JK |
37 | }; |
38 | ||
51580e79 AS |
39 | /* bpf_check() is a static code analyzer that walks eBPF program |
40 | * instruction by instruction and updates register/stack state. | |
41 | * All paths of conditional branches are analyzed until 'bpf_exit' insn. | |
42 | * | |
43 | * The first pass is depth-first-search to check that the program is a DAG. | |
44 | * It rejects the following programs: | |
45 | * - larger than BPF_MAXINSNS insns | |
46 | * - if loop is present (detected via back-edge) | |
47 | * - unreachable insns exist (shouldn't be a forest. program = one function) | |
48 | * - out of bounds or malformed jumps | |
49 | * The second pass is all possible path descent from the 1st insn. | |
50 | * Since it's analyzing all pathes through the program, the length of the | |
eba38a96 | 51 | * analysis is limited to 64k insn, which may be hit even if total number of |
51580e79 AS |
52 | * insn is less then 4K, but there are too many branches that change stack/regs. |
53 | * Number of 'branches to be analyzed' is limited to 1k | |
54 | * | |
55 | * On entry to each instruction, each register has a type, and the instruction | |
56 | * changes the types of the registers depending on instruction semantics. | |
57 | * If instruction is BPF_MOV64_REG(BPF_REG_1, BPF_REG_5), then type of R5 is | |
58 | * copied to R1. | |
59 | * | |
60 | * All registers are 64-bit. | |
61 | * R0 - return register | |
62 | * R1-R5 argument passing registers | |
63 | * R6-R9 callee saved registers | |
64 | * R10 - frame pointer read-only | |
65 | * | |
66 | * At the start of BPF program the register R1 contains a pointer to bpf_context | |
67 | * and has type PTR_TO_CTX. | |
68 | * | |
69 | * Verifier tracks arithmetic operations on pointers in case: | |
70 | * BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), | |
71 | * BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -20), | |
72 | * 1st insn copies R10 (which has FRAME_PTR) type into R1 | |
73 | * and 2nd arithmetic instruction is pattern matched to recognize | |
74 | * that it wants to construct a pointer to some element within stack. | |
75 | * So after 2nd insn, the register R1 has type PTR_TO_STACK | |
76 | * (and -20 constant is saved for further stack bounds checking). | |
77 | * Meaning that this reg is a pointer to stack plus known immediate constant. | |
78 | * | |
f1174f77 | 79 | * Most of the time the registers have SCALAR_VALUE type, which |
51580e79 | 80 | * means the register has some value, but it's not a valid pointer. |
f1174f77 | 81 | * (like pointer plus pointer becomes SCALAR_VALUE type) |
51580e79 AS |
82 | * |
83 | * When verifier sees load or store instructions the type of base register | |
c64b7983 JS |
84 | * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK, PTR_TO_SOCKET. These are |
85 | * four pointer types recognized by check_mem_access() function. | |
51580e79 AS |
86 | * |
87 | * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value' | |
88 | * and the range of [ptr, ptr + map's value_size) is accessible. | |
89 | * | |
90 | * registers used to pass values to function calls are checked against | |
91 | * function argument constraints. | |
92 | * | |
93 | * ARG_PTR_TO_MAP_KEY is one of such argument constraints. | |
94 | * It means that the register type passed to this function must be | |
95 | * PTR_TO_STACK and it will be used inside the function as | |
96 | * 'pointer to map element key' | |
97 | * | |
98 | * For example the argument constraints for bpf_map_lookup_elem(): | |
99 | * .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, | |
100 | * .arg1_type = ARG_CONST_MAP_PTR, | |
101 | * .arg2_type = ARG_PTR_TO_MAP_KEY, | |
102 | * | |
103 | * ret_type says that this function returns 'pointer to map elem value or null' | |
104 | * function expects 1st argument to be a const pointer to 'struct bpf_map' and | |
105 | * 2nd argument should be a pointer to stack, which will be used inside | |
106 | * the helper function as a pointer to map element key. | |
107 | * | |
108 | * On the kernel side the helper function looks like: | |
109 | * u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) | |
110 | * { | |
111 | * struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; | |
112 | * void *key = (void *) (unsigned long) r2; | |
113 | * void *value; | |
114 | * | |
115 | * here kernel can access 'key' and 'map' pointers safely, knowing that | |
116 | * [key, key + map->key_size) bytes are valid and were initialized on | |
117 | * the stack of eBPF program. | |
118 | * } | |
119 | * | |
120 | * Corresponding eBPF program may look like: | |
121 | * BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), // after this insn R2 type is FRAME_PTR | |
122 | * BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), // after this insn R2 type is PTR_TO_STACK | |
123 | * BPF_LD_MAP_FD(BPF_REG_1, map_fd), // after this insn R1 type is CONST_PTR_TO_MAP | |
124 | * BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), | |
125 | * here verifier looks at prototype of map_lookup_elem() and sees: | |
126 | * .arg1_type == ARG_CONST_MAP_PTR and R1->type == CONST_PTR_TO_MAP, which is ok, | |
127 | * Now verifier knows that this map has key of R1->map_ptr->key_size bytes | |
128 | * | |
129 | * Then .arg2_type == ARG_PTR_TO_MAP_KEY and R2->type == PTR_TO_STACK, ok so far, | |
130 | * Now verifier checks that [R2, R2 + map's key_size) are within stack limits | |
131 | * and were initialized prior to this call. | |
132 | * If it's ok, then verifier allows this BPF_CALL insn and looks at | |
133 | * .ret_type which is RET_PTR_TO_MAP_VALUE_OR_NULL, so it sets | |
134 | * R0->type = PTR_TO_MAP_VALUE_OR_NULL which means bpf_map_lookup_elem() function | |
135 | * returns ether pointer to map value or NULL. | |
136 | * | |
137 | * When type PTR_TO_MAP_VALUE_OR_NULL passes through 'if (reg != 0) goto +off' | |
138 | * insn, the register holding that pointer in the true branch changes state to | |
139 | * PTR_TO_MAP_VALUE and the same register changes state to CONST_IMM in the false | |
140 | * branch. See check_cond_jmp_op(). | |
141 | * | |
142 | * After the call R0 is set to return type of the function and registers R1-R5 | |
143 | * are set to NOT_INIT to indicate that they are no longer readable. | |
fd978bf7 JS |
144 | * |
145 | * The following reference types represent a potential reference to a kernel | |
146 | * resource which, after first being allocated, must be checked and freed by | |
147 | * the BPF program: | |
148 | * - PTR_TO_SOCKET_OR_NULL, PTR_TO_SOCKET | |
149 | * | |
150 | * When the verifier sees a helper call return a reference type, it allocates a | |
151 | * pointer id for the reference and stores it in the current function state. | |
152 | * Similar to the way that PTR_TO_MAP_VALUE_OR_NULL is converted into | |
153 | * PTR_TO_MAP_VALUE, PTR_TO_SOCKET_OR_NULL becomes PTR_TO_SOCKET when the type | |
154 | * passes through a NULL-check conditional. For the branch wherein the state is | |
155 | * changed to CONST_IMM, the verifier releases the reference. | |
6acc9b43 JS |
156 | * |
157 | * For each helper function that allocates a reference, such as | |
158 | * bpf_sk_lookup_tcp(), there is a corresponding release function, such as | |
159 | * bpf_sk_release(). When a reference type passes into the release function, | |
160 | * the verifier also releases the reference. If any unchecked or unreleased | |
161 | * reference remains at the end of the program, the verifier rejects it. | |
51580e79 AS |
162 | */ |
163 | ||
17a52670 | 164 | /* verifier_state + insn_idx are pushed to stack when branch is encountered */ |
58e2af8b | 165 | struct bpf_verifier_stack_elem { |
17a52670 AS |
166 | /* verifer state is 'st' |
167 | * before processing instruction 'insn_idx' | |
168 | * and after processing instruction 'prev_insn_idx' | |
169 | */ | |
58e2af8b | 170 | struct bpf_verifier_state st; |
17a52670 AS |
171 | int insn_idx; |
172 | int prev_insn_idx; | |
58e2af8b | 173 | struct bpf_verifier_stack_elem *next; |
6f8a57cc AN |
174 | /* length of verifier log at the time this state was pushed on stack */ |
175 | u32 log_pos; | |
cbd35700 AS |
176 | }; |
177 | ||
b285fcb7 | 178 | #define BPF_COMPLEXITY_LIMIT_JMP_SEQ 8192 |
ceefbc96 | 179 | #define BPF_COMPLEXITY_LIMIT_STATES 64 |
07016151 | 180 | |
d2e4c1e6 DB |
181 | #define BPF_MAP_KEY_POISON (1ULL << 63) |
182 | #define BPF_MAP_KEY_SEEN (1ULL << 62) | |
183 | ||
c93552c4 DB |
184 | #define BPF_MAP_PTR_UNPRIV 1UL |
185 | #define BPF_MAP_PTR_POISON ((void *)((0xeB9FUL << 1) + \ | |
186 | POISON_POINTER_DELTA)) | |
187 | #define BPF_MAP_PTR(X) ((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV)) | |
188 | ||
189 | static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux) | |
190 | { | |
d2e4c1e6 | 191 | return BPF_MAP_PTR(aux->map_ptr_state) == BPF_MAP_PTR_POISON; |
c93552c4 DB |
192 | } |
193 | ||
194 | static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data *aux) | |
195 | { | |
d2e4c1e6 | 196 | return aux->map_ptr_state & BPF_MAP_PTR_UNPRIV; |
c93552c4 DB |
197 | } |
198 | ||
199 | static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux, | |
200 | const struct bpf_map *map, bool unpriv) | |
201 | { | |
202 | BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON & BPF_MAP_PTR_UNPRIV); | |
203 | unpriv |= bpf_map_ptr_unpriv(aux); | |
d2e4c1e6 DB |
204 | aux->map_ptr_state = (unsigned long)map | |
205 | (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL); | |
206 | } | |
207 | ||
208 | static bool bpf_map_key_poisoned(const struct bpf_insn_aux_data *aux) | |
209 | { | |
210 | return aux->map_key_state & BPF_MAP_KEY_POISON; | |
211 | } | |
212 | ||
213 | static bool bpf_map_key_unseen(const struct bpf_insn_aux_data *aux) | |
214 | { | |
215 | return !(aux->map_key_state & BPF_MAP_KEY_SEEN); | |
216 | } | |
217 | ||
218 | static u64 bpf_map_key_immediate(const struct bpf_insn_aux_data *aux) | |
219 | { | |
220 | return aux->map_key_state & ~(BPF_MAP_KEY_SEEN | BPF_MAP_KEY_POISON); | |
221 | } | |
222 | ||
223 | static void bpf_map_key_store(struct bpf_insn_aux_data *aux, u64 state) | |
224 | { | |
225 | bool poisoned = bpf_map_key_poisoned(aux); | |
226 | ||
227 | aux->map_key_state = state | BPF_MAP_KEY_SEEN | | |
228 | (poisoned ? BPF_MAP_KEY_POISON : 0ULL); | |
c93552c4 | 229 | } |
fad73a1a | 230 | |
23a2d70c YS |
231 | static bool bpf_pseudo_call(const struct bpf_insn *insn) |
232 | { | |
233 | return insn->code == (BPF_JMP | BPF_CALL) && | |
234 | insn->src_reg == BPF_PSEUDO_CALL; | |
235 | } | |
236 | ||
33ff9823 DB |
237 | struct bpf_call_arg_meta { |
238 | struct bpf_map *map_ptr; | |
435faee1 | 239 | bool raw_mode; |
36bbef52 | 240 | bool pkt_access; |
435faee1 DB |
241 | int regno; |
242 | int access_size; | |
457f4436 | 243 | int mem_size; |
10060503 | 244 | u64 msize_max_value; |
1b986589 | 245 | int ref_obj_id; |
d83525ca | 246 | int func_id; |
22dc4a0f | 247 | struct btf *btf; |
eaa6bcb7 | 248 | u32 btf_id; |
22dc4a0f | 249 | struct btf *ret_btf; |
eaa6bcb7 | 250 | u32 ret_btf_id; |
33ff9823 DB |
251 | }; |
252 | ||
8580ac94 AS |
253 | struct btf *btf_vmlinux; |
254 | ||
cbd35700 AS |
255 | static DEFINE_MUTEX(bpf_verifier_lock); |
256 | ||
d9762e84 MKL |
257 | static const struct bpf_line_info * |
258 | find_linfo(const struct bpf_verifier_env *env, u32 insn_off) | |
259 | { | |
260 | const struct bpf_line_info *linfo; | |
261 | const struct bpf_prog *prog; | |
262 | u32 i, nr_linfo; | |
263 | ||
264 | prog = env->prog; | |
265 | nr_linfo = prog->aux->nr_linfo; | |
266 | ||
267 | if (!nr_linfo || insn_off >= prog->len) | |
268 | return NULL; | |
269 | ||
270 | linfo = prog->aux->linfo; | |
271 | for (i = 1; i < nr_linfo; i++) | |
272 | if (insn_off < linfo[i].insn_off) | |
273 | break; | |
274 | ||
275 | return &linfo[i - 1]; | |
276 | } | |
277 | ||
77d2e05a MKL |
278 | void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt, |
279 | va_list args) | |
cbd35700 | 280 | { |
a2a7d570 | 281 | unsigned int n; |
cbd35700 | 282 | |
a2a7d570 | 283 | n = vscnprintf(log->kbuf, BPF_VERIFIER_TMP_LOG_SIZE, fmt, args); |
a2a7d570 JK |
284 | |
285 | WARN_ONCE(n >= BPF_VERIFIER_TMP_LOG_SIZE - 1, | |
286 | "verifier log line truncated - local buffer too short\n"); | |
287 | ||
288 | n = min(log->len_total - log->len_used - 1, n); | |
289 | log->kbuf[n] = '\0'; | |
290 | ||
8580ac94 AS |
291 | if (log->level == BPF_LOG_KERNEL) { |
292 | pr_err("BPF:%s\n", log->kbuf); | |
293 | return; | |
294 | } | |
a2a7d570 JK |
295 | if (!copy_to_user(log->ubuf + log->len_used, log->kbuf, n + 1)) |
296 | log->len_used += n; | |
297 | else | |
298 | log->ubuf = NULL; | |
cbd35700 | 299 | } |
abe08840 | 300 | |
6f8a57cc AN |
301 | static void bpf_vlog_reset(struct bpf_verifier_log *log, u32 new_pos) |
302 | { | |
303 | char zero = 0; | |
304 | ||
305 | if (!bpf_verifier_log_needed(log)) | |
306 | return; | |
307 | ||
308 | log->len_used = new_pos; | |
309 | if (put_user(zero, log->ubuf + new_pos)) | |
310 | log->ubuf = NULL; | |
311 | } | |
312 | ||
abe08840 JO |
313 | /* log_level controls verbosity level of eBPF verifier. |
314 | * bpf_verifier_log_write() is used to dump the verification trace to the log, | |
315 | * so the user can figure out what's wrong with the program | |
430e68d1 | 316 | */ |
abe08840 JO |
317 | __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env, |
318 | const char *fmt, ...) | |
319 | { | |
320 | va_list args; | |
321 | ||
77d2e05a MKL |
322 | if (!bpf_verifier_log_needed(&env->log)) |
323 | return; | |
324 | ||
abe08840 | 325 | va_start(args, fmt); |
77d2e05a | 326 | bpf_verifier_vlog(&env->log, fmt, args); |
abe08840 JO |
327 | va_end(args); |
328 | } | |
329 | EXPORT_SYMBOL_GPL(bpf_verifier_log_write); | |
330 | ||
331 | __printf(2, 3) static void verbose(void *private_data, const char *fmt, ...) | |
332 | { | |
77d2e05a | 333 | struct bpf_verifier_env *env = private_data; |
abe08840 JO |
334 | va_list args; |
335 | ||
77d2e05a MKL |
336 | if (!bpf_verifier_log_needed(&env->log)) |
337 | return; | |
338 | ||
abe08840 | 339 | va_start(args, fmt); |
77d2e05a | 340 | bpf_verifier_vlog(&env->log, fmt, args); |
abe08840 JO |
341 | va_end(args); |
342 | } | |
cbd35700 | 343 | |
9e15db66 AS |
344 | __printf(2, 3) void bpf_log(struct bpf_verifier_log *log, |
345 | const char *fmt, ...) | |
346 | { | |
347 | va_list args; | |
348 | ||
349 | if (!bpf_verifier_log_needed(log)) | |
350 | return; | |
351 | ||
352 | va_start(args, fmt); | |
353 | bpf_verifier_vlog(log, fmt, args); | |
354 | va_end(args); | |
355 | } | |
356 | ||
d9762e84 MKL |
357 | static const char *ltrim(const char *s) |
358 | { | |
359 | while (isspace(*s)) | |
360 | s++; | |
361 | ||
362 | return s; | |
363 | } | |
364 | ||
365 | __printf(3, 4) static void verbose_linfo(struct bpf_verifier_env *env, | |
366 | u32 insn_off, | |
367 | const char *prefix_fmt, ...) | |
368 | { | |
369 | const struct bpf_line_info *linfo; | |
370 | ||
371 | if (!bpf_verifier_log_needed(&env->log)) | |
372 | return; | |
373 | ||
374 | linfo = find_linfo(env, insn_off); | |
375 | if (!linfo || linfo == env->prev_linfo) | |
376 | return; | |
377 | ||
378 | if (prefix_fmt) { | |
379 | va_list args; | |
380 | ||
381 | va_start(args, prefix_fmt); | |
382 | bpf_verifier_vlog(&env->log, prefix_fmt, args); | |
383 | va_end(args); | |
384 | } | |
385 | ||
386 | verbose(env, "%s\n", | |
387 | ltrim(btf_name_by_offset(env->prog->aux->btf, | |
388 | linfo->line_off))); | |
389 | ||
390 | env->prev_linfo = linfo; | |
391 | } | |
392 | ||
de8f3a83 DB |
393 | static bool type_is_pkt_pointer(enum bpf_reg_type type) |
394 | { | |
395 | return type == PTR_TO_PACKET || | |
396 | type == PTR_TO_PACKET_META; | |
397 | } | |
398 | ||
46f8bc92 MKL |
399 | static bool type_is_sk_pointer(enum bpf_reg_type type) |
400 | { | |
401 | return type == PTR_TO_SOCKET || | |
655a51e5 | 402 | type == PTR_TO_SOCK_COMMON || |
fada7fdc JL |
403 | type == PTR_TO_TCP_SOCK || |
404 | type == PTR_TO_XDP_SOCK; | |
46f8bc92 MKL |
405 | } |
406 | ||
cac616db JF |
407 | static bool reg_type_not_null(enum bpf_reg_type type) |
408 | { | |
409 | return type == PTR_TO_SOCKET || | |
410 | type == PTR_TO_TCP_SOCK || | |
411 | type == PTR_TO_MAP_VALUE || | |
01c66c48 | 412 | type == PTR_TO_SOCK_COMMON; |
cac616db JF |
413 | } |
414 | ||
840b9615 JS |
415 | static bool reg_type_may_be_null(enum bpf_reg_type type) |
416 | { | |
fd978bf7 | 417 | return type == PTR_TO_MAP_VALUE_OR_NULL || |
46f8bc92 | 418 | type == PTR_TO_SOCKET_OR_NULL || |
655a51e5 | 419 | type == PTR_TO_SOCK_COMMON_OR_NULL || |
b121b341 | 420 | type == PTR_TO_TCP_SOCK_OR_NULL || |
457f4436 | 421 | type == PTR_TO_BTF_ID_OR_NULL || |
afbf21dc YS |
422 | type == PTR_TO_MEM_OR_NULL || |
423 | type == PTR_TO_RDONLY_BUF_OR_NULL || | |
424 | type == PTR_TO_RDWR_BUF_OR_NULL; | |
fd978bf7 JS |
425 | } |
426 | ||
d83525ca AS |
427 | static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg) |
428 | { | |
429 | return reg->type == PTR_TO_MAP_VALUE && | |
430 | map_value_has_spin_lock(reg->map_ptr); | |
431 | } | |
432 | ||
cba368c1 MKL |
433 | static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type) |
434 | { | |
435 | return type == PTR_TO_SOCKET || | |
436 | type == PTR_TO_SOCKET_OR_NULL || | |
437 | type == PTR_TO_TCP_SOCK || | |
457f4436 AN |
438 | type == PTR_TO_TCP_SOCK_OR_NULL || |
439 | type == PTR_TO_MEM || | |
440 | type == PTR_TO_MEM_OR_NULL; | |
cba368c1 MKL |
441 | } |
442 | ||
1b986589 | 443 | static bool arg_type_may_be_refcounted(enum bpf_arg_type type) |
fd978bf7 | 444 | { |
1b986589 | 445 | return type == ARG_PTR_TO_SOCK_COMMON; |
fd978bf7 JS |
446 | } |
447 | ||
fd1b0d60 LB |
448 | static bool arg_type_may_be_null(enum bpf_arg_type type) |
449 | { | |
450 | return type == ARG_PTR_TO_MAP_VALUE_OR_NULL || | |
451 | type == ARG_PTR_TO_MEM_OR_NULL || | |
452 | type == ARG_PTR_TO_CTX_OR_NULL || | |
453 | type == ARG_PTR_TO_SOCKET_OR_NULL || | |
454 | type == ARG_PTR_TO_ALLOC_MEM_OR_NULL; | |
455 | } | |
456 | ||
fd978bf7 JS |
457 | /* Determine whether the function releases some resources allocated by another |
458 | * function call. The first reference type argument will be assumed to be | |
459 | * released by release_reference(). | |
460 | */ | |
461 | static bool is_release_function(enum bpf_func_id func_id) | |
462 | { | |
457f4436 AN |
463 | return func_id == BPF_FUNC_sk_release || |
464 | func_id == BPF_FUNC_ringbuf_submit || | |
465 | func_id == BPF_FUNC_ringbuf_discard; | |
840b9615 JS |
466 | } |
467 | ||
64d85290 | 468 | static bool may_be_acquire_function(enum bpf_func_id func_id) |
46f8bc92 MKL |
469 | { |
470 | return func_id == BPF_FUNC_sk_lookup_tcp || | |
edbf8c01 | 471 | func_id == BPF_FUNC_sk_lookup_udp || |
64d85290 | 472 | func_id == BPF_FUNC_skc_lookup_tcp || |
457f4436 AN |
473 | func_id == BPF_FUNC_map_lookup_elem || |
474 | func_id == BPF_FUNC_ringbuf_reserve; | |
64d85290 JS |
475 | } |
476 | ||
477 | static bool is_acquire_function(enum bpf_func_id func_id, | |
478 | const struct bpf_map *map) | |
479 | { | |
480 | enum bpf_map_type map_type = map ? map->map_type : BPF_MAP_TYPE_UNSPEC; | |
481 | ||
482 | if (func_id == BPF_FUNC_sk_lookup_tcp || | |
483 | func_id == BPF_FUNC_sk_lookup_udp || | |
457f4436 AN |
484 | func_id == BPF_FUNC_skc_lookup_tcp || |
485 | func_id == BPF_FUNC_ringbuf_reserve) | |
64d85290 JS |
486 | return true; |
487 | ||
488 | if (func_id == BPF_FUNC_map_lookup_elem && | |
489 | (map_type == BPF_MAP_TYPE_SOCKMAP || | |
490 | map_type == BPF_MAP_TYPE_SOCKHASH)) | |
491 | return true; | |
492 | ||
493 | return false; | |
46f8bc92 MKL |
494 | } |
495 | ||
1b986589 MKL |
496 | static bool is_ptr_cast_function(enum bpf_func_id func_id) |
497 | { | |
498 | return func_id == BPF_FUNC_tcp_sock || | |
1df8f55a MKL |
499 | func_id == BPF_FUNC_sk_fullsock || |
500 | func_id == BPF_FUNC_skc_to_tcp_sock || | |
501 | func_id == BPF_FUNC_skc_to_tcp6_sock || | |
502 | func_id == BPF_FUNC_skc_to_udp6_sock || | |
503 | func_id == BPF_FUNC_skc_to_tcp_timewait_sock || | |
504 | func_id == BPF_FUNC_skc_to_tcp_request_sock; | |
1b986589 MKL |
505 | } |
506 | ||
39491867 BJ |
507 | static bool is_cmpxchg_insn(const struct bpf_insn *insn) |
508 | { | |
509 | return BPF_CLASS(insn->code) == BPF_STX && | |
510 | BPF_MODE(insn->code) == BPF_ATOMIC && | |
511 | insn->imm == BPF_CMPXCHG; | |
512 | } | |
513 | ||
17a52670 AS |
514 | /* string representation of 'enum bpf_reg_type' */ |
515 | static const char * const reg_type_str[] = { | |
516 | [NOT_INIT] = "?", | |
f1174f77 | 517 | [SCALAR_VALUE] = "inv", |
17a52670 AS |
518 | [PTR_TO_CTX] = "ctx", |
519 | [CONST_PTR_TO_MAP] = "map_ptr", | |
520 | [PTR_TO_MAP_VALUE] = "map_value", | |
521 | [PTR_TO_MAP_VALUE_OR_NULL] = "map_value_or_null", | |
17a52670 | 522 | [PTR_TO_STACK] = "fp", |
969bf05e | 523 | [PTR_TO_PACKET] = "pkt", |
de8f3a83 | 524 | [PTR_TO_PACKET_META] = "pkt_meta", |
969bf05e | 525 | [PTR_TO_PACKET_END] = "pkt_end", |
d58e468b | 526 | [PTR_TO_FLOW_KEYS] = "flow_keys", |
c64b7983 JS |
527 | [PTR_TO_SOCKET] = "sock", |
528 | [PTR_TO_SOCKET_OR_NULL] = "sock_or_null", | |
46f8bc92 MKL |
529 | [PTR_TO_SOCK_COMMON] = "sock_common", |
530 | [PTR_TO_SOCK_COMMON_OR_NULL] = "sock_common_or_null", | |
655a51e5 MKL |
531 | [PTR_TO_TCP_SOCK] = "tcp_sock", |
532 | [PTR_TO_TCP_SOCK_OR_NULL] = "tcp_sock_or_null", | |
9df1c28b | 533 | [PTR_TO_TP_BUFFER] = "tp_buffer", |
fada7fdc | 534 | [PTR_TO_XDP_SOCK] = "xdp_sock", |
9e15db66 | 535 | [PTR_TO_BTF_ID] = "ptr_", |
b121b341 | 536 | [PTR_TO_BTF_ID_OR_NULL] = "ptr_or_null_", |
eaa6bcb7 | 537 | [PTR_TO_PERCPU_BTF_ID] = "percpu_ptr_", |
457f4436 AN |
538 | [PTR_TO_MEM] = "mem", |
539 | [PTR_TO_MEM_OR_NULL] = "mem_or_null", | |
afbf21dc YS |
540 | [PTR_TO_RDONLY_BUF] = "rdonly_buf", |
541 | [PTR_TO_RDONLY_BUF_OR_NULL] = "rdonly_buf_or_null", | |
542 | [PTR_TO_RDWR_BUF] = "rdwr_buf", | |
543 | [PTR_TO_RDWR_BUF_OR_NULL] = "rdwr_buf_or_null", | |
17a52670 AS |
544 | }; |
545 | ||
8efea21d EC |
546 | static char slot_type_char[] = { |
547 | [STACK_INVALID] = '?', | |
548 | [STACK_SPILL] = 'r', | |
549 | [STACK_MISC] = 'm', | |
550 | [STACK_ZERO] = '0', | |
551 | }; | |
552 | ||
4e92024a AS |
553 | static void print_liveness(struct bpf_verifier_env *env, |
554 | enum bpf_reg_liveness live) | |
555 | { | |
9242b5f5 | 556 | if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN | REG_LIVE_DONE)) |
4e92024a AS |
557 | verbose(env, "_"); |
558 | if (live & REG_LIVE_READ) | |
559 | verbose(env, "r"); | |
560 | if (live & REG_LIVE_WRITTEN) | |
561 | verbose(env, "w"); | |
9242b5f5 AS |
562 | if (live & REG_LIVE_DONE) |
563 | verbose(env, "D"); | |
4e92024a AS |
564 | } |
565 | ||
f4d7e40a AS |
566 | static struct bpf_func_state *func(struct bpf_verifier_env *env, |
567 | const struct bpf_reg_state *reg) | |
568 | { | |
569 | struct bpf_verifier_state *cur = env->cur_state; | |
570 | ||
571 | return cur->frame[reg->frameno]; | |
572 | } | |
573 | ||
22dc4a0f | 574 | static const char *kernel_type_name(const struct btf* btf, u32 id) |
9e15db66 | 575 | { |
22dc4a0f | 576 | return btf_name_by_offset(btf, btf_type_by_id(btf, id)->name_off); |
9e15db66 AS |
577 | } |
578 | ||
61bd5218 | 579 | static void print_verifier_state(struct bpf_verifier_env *env, |
f4d7e40a | 580 | const struct bpf_func_state *state) |
17a52670 | 581 | { |
f4d7e40a | 582 | const struct bpf_reg_state *reg; |
17a52670 AS |
583 | enum bpf_reg_type t; |
584 | int i; | |
585 | ||
f4d7e40a AS |
586 | if (state->frameno) |
587 | verbose(env, " frame%d:", state->frameno); | |
17a52670 | 588 | for (i = 0; i < MAX_BPF_REG; i++) { |
1a0dc1ac AS |
589 | reg = &state->regs[i]; |
590 | t = reg->type; | |
17a52670 AS |
591 | if (t == NOT_INIT) |
592 | continue; | |
4e92024a AS |
593 | verbose(env, " R%d", i); |
594 | print_liveness(env, reg->live); | |
595 | verbose(env, "=%s", reg_type_str[t]); | |
b5dc0163 AS |
596 | if (t == SCALAR_VALUE && reg->precise) |
597 | verbose(env, "P"); | |
f1174f77 EC |
598 | if ((t == SCALAR_VALUE || t == PTR_TO_STACK) && |
599 | tnum_is_const(reg->var_off)) { | |
600 | /* reg->off should be 0 for SCALAR_VALUE */ | |
61bd5218 | 601 | verbose(env, "%lld", reg->var_off.value + reg->off); |
f1174f77 | 602 | } else { |
eaa6bcb7 HL |
603 | if (t == PTR_TO_BTF_ID || |
604 | t == PTR_TO_BTF_ID_OR_NULL || | |
605 | t == PTR_TO_PERCPU_BTF_ID) | |
22dc4a0f | 606 | verbose(env, "%s", kernel_type_name(reg->btf, reg->btf_id)); |
cba368c1 MKL |
607 | verbose(env, "(id=%d", reg->id); |
608 | if (reg_type_may_be_refcounted_or_null(t)) | |
609 | verbose(env, ",ref_obj_id=%d", reg->ref_obj_id); | |
f1174f77 | 610 | if (t != SCALAR_VALUE) |
61bd5218 | 611 | verbose(env, ",off=%d", reg->off); |
de8f3a83 | 612 | if (type_is_pkt_pointer(t)) |
61bd5218 | 613 | verbose(env, ",r=%d", reg->range); |
f1174f77 EC |
614 | else if (t == CONST_PTR_TO_MAP || |
615 | t == PTR_TO_MAP_VALUE || | |
616 | t == PTR_TO_MAP_VALUE_OR_NULL) | |
61bd5218 | 617 | verbose(env, ",ks=%d,vs=%d", |
f1174f77 EC |
618 | reg->map_ptr->key_size, |
619 | reg->map_ptr->value_size); | |
7d1238f2 EC |
620 | if (tnum_is_const(reg->var_off)) { |
621 | /* Typically an immediate SCALAR_VALUE, but | |
622 | * could be a pointer whose offset is too big | |
623 | * for reg->off | |
624 | */ | |
61bd5218 | 625 | verbose(env, ",imm=%llx", reg->var_off.value); |
7d1238f2 EC |
626 | } else { |
627 | if (reg->smin_value != reg->umin_value && | |
628 | reg->smin_value != S64_MIN) | |
61bd5218 | 629 | verbose(env, ",smin_value=%lld", |
7d1238f2 EC |
630 | (long long)reg->smin_value); |
631 | if (reg->smax_value != reg->umax_value && | |
632 | reg->smax_value != S64_MAX) | |
61bd5218 | 633 | verbose(env, ",smax_value=%lld", |
7d1238f2 EC |
634 | (long long)reg->smax_value); |
635 | if (reg->umin_value != 0) | |
61bd5218 | 636 | verbose(env, ",umin_value=%llu", |
7d1238f2 EC |
637 | (unsigned long long)reg->umin_value); |
638 | if (reg->umax_value != U64_MAX) | |
61bd5218 | 639 | verbose(env, ",umax_value=%llu", |
7d1238f2 EC |
640 | (unsigned long long)reg->umax_value); |
641 | if (!tnum_is_unknown(reg->var_off)) { | |
642 | char tn_buf[48]; | |
f1174f77 | 643 | |
7d1238f2 | 644 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); |
61bd5218 | 645 | verbose(env, ",var_off=%s", tn_buf); |
7d1238f2 | 646 | } |
3f50f132 JF |
647 | if (reg->s32_min_value != reg->smin_value && |
648 | reg->s32_min_value != S32_MIN) | |
649 | verbose(env, ",s32_min_value=%d", | |
650 | (int)(reg->s32_min_value)); | |
651 | if (reg->s32_max_value != reg->smax_value && | |
652 | reg->s32_max_value != S32_MAX) | |
653 | verbose(env, ",s32_max_value=%d", | |
654 | (int)(reg->s32_max_value)); | |
655 | if (reg->u32_min_value != reg->umin_value && | |
656 | reg->u32_min_value != U32_MIN) | |
657 | verbose(env, ",u32_min_value=%d", | |
658 | (int)(reg->u32_min_value)); | |
659 | if (reg->u32_max_value != reg->umax_value && | |
660 | reg->u32_max_value != U32_MAX) | |
661 | verbose(env, ",u32_max_value=%d", | |
662 | (int)(reg->u32_max_value)); | |
f1174f77 | 663 | } |
61bd5218 | 664 | verbose(env, ")"); |
f1174f77 | 665 | } |
17a52670 | 666 | } |
638f5b90 | 667 | for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) { |
8efea21d EC |
668 | char types_buf[BPF_REG_SIZE + 1]; |
669 | bool valid = false; | |
670 | int j; | |
671 | ||
672 | for (j = 0; j < BPF_REG_SIZE; j++) { | |
673 | if (state->stack[i].slot_type[j] != STACK_INVALID) | |
674 | valid = true; | |
675 | types_buf[j] = slot_type_char[ | |
676 | state->stack[i].slot_type[j]]; | |
677 | } | |
678 | types_buf[BPF_REG_SIZE] = 0; | |
679 | if (!valid) | |
680 | continue; | |
681 | verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE); | |
682 | print_liveness(env, state->stack[i].spilled_ptr.live); | |
b5dc0163 AS |
683 | if (state->stack[i].slot_type[0] == STACK_SPILL) { |
684 | reg = &state->stack[i].spilled_ptr; | |
685 | t = reg->type; | |
686 | verbose(env, "=%s", reg_type_str[t]); | |
687 | if (t == SCALAR_VALUE && reg->precise) | |
688 | verbose(env, "P"); | |
689 | if (t == SCALAR_VALUE && tnum_is_const(reg->var_off)) | |
690 | verbose(env, "%lld", reg->var_off.value + reg->off); | |
691 | } else { | |
8efea21d | 692 | verbose(env, "=%s", types_buf); |
b5dc0163 | 693 | } |
17a52670 | 694 | } |
fd978bf7 JS |
695 | if (state->acquired_refs && state->refs[0].id) { |
696 | verbose(env, " refs=%d", state->refs[0].id); | |
697 | for (i = 1; i < state->acquired_refs; i++) | |
698 | if (state->refs[i].id) | |
699 | verbose(env, ",%d", state->refs[i].id); | |
700 | } | |
61bd5218 | 701 | verbose(env, "\n"); |
17a52670 AS |
702 | } |
703 | ||
84dbf350 JS |
704 | #define COPY_STATE_FN(NAME, COUNT, FIELD, SIZE) \ |
705 | static int copy_##NAME##_state(struct bpf_func_state *dst, \ | |
706 | const struct bpf_func_state *src) \ | |
707 | { \ | |
708 | if (!src->FIELD) \ | |
709 | return 0; \ | |
710 | if (WARN_ON_ONCE(dst->COUNT < src->COUNT)) { \ | |
711 | /* internal bug, make state invalid to reject the program */ \ | |
712 | memset(dst, 0, sizeof(*dst)); \ | |
713 | return -EFAULT; \ | |
714 | } \ | |
715 | memcpy(dst->FIELD, src->FIELD, \ | |
716 | sizeof(*src->FIELD) * (src->COUNT / SIZE)); \ | |
717 | return 0; \ | |
638f5b90 | 718 | } |
fd978bf7 JS |
719 | /* copy_reference_state() */ |
720 | COPY_STATE_FN(reference, acquired_refs, refs, 1) | |
84dbf350 JS |
721 | /* copy_stack_state() */ |
722 | COPY_STATE_FN(stack, allocated_stack, stack, BPF_REG_SIZE) | |
723 | #undef COPY_STATE_FN | |
724 | ||
725 | #define REALLOC_STATE_FN(NAME, COUNT, FIELD, SIZE) \ | |
726 | static int realloc_##NAME##_state(struct bpf_func_state *state, int size, \ | |
727 | bool copy_old) \ | |
728 | { \ | |
729 | u32 old_size = state->COUNT; \ | |
730 | struct bpf_##NAME##_state *new_##FIELD; \ | |
731 | int slot = size / SIZE; \ | |
732 | \ | |
733 | if (size <= old_size || !size) { \ | |
734 | if (copy_old) \ | |
735 | return 0; \ | |
736 | state->COUNT = slot * SIZE; \ | |
737 | if (!size && old_size) { \ | |
738 | kfree(state->FIELD); \ | |
739 | state->FIELD = NULL; \ | |
740 | } \ | |
741 | return 0; \ | |
742 | } \ | |
743 | new_##FIELD = kmalloc_array(slot, sizeof(struct bpf_##NAME##_state), \ | |
744 | GFP_KERNEL); \ | |
745 | if (!new_##FIELD) \ | |
746 | return -ENOMEM; \ | |
747 | if (copy_old) { \ | |
748 | if (state->FIELD) \ | |
749 | memcpy(new_##FIELD, state->FIELD, \ | |
750 | sizeof(*new_##FIELD) * (old_size / SIZE)); \ | |
751 | memset(new_##FIELD + old_size / SIZE, 0, \ | |
752 | sizeof(*new_##FIELD) * (size - old_size) / SIZE); \ | |
753 | } \ | |
754 | state->COUNT = slot * SIZE; \ | |
755 | kfree(state->FIELD); \ | |
756 | state->FIELD = new_##FIELD; \ | |
757 | return 0; \ | |
758 | } | |
fd978bf7 JS |
759 | /* realloc_reference_state() */ |
760 | REALLOC_STATE_FN(reference, acquired_refs, refs, 1) | |
84dbf350 JS |
761 | /* realloc_stack_state() */ |
762 | REALLOC_STATE_FN(stack, allocated_stack, stack, BPF_REG_SIZE) | |
763 | #undef REALLOC_STATE_FN | |
638f5b90 AS |
764 | |
765 | /* do_check() starts with zero-sized stack in struct bpf_verifier_state to | |
766 | * make it consume minimal amount of memory. check_stack_write() access from | |
f4d7e40a | 767 | * the program calls into realloc_func_state() to grow the stack size. |
84dbf350 JS |
768 | * Note there is a non-zero 'parent' pointer inside bpf_verifier_state |
769 | * which realloc_stack_state() copies over. It points to previous | |
770 | * bpf_verifier_state which is never reallocated. | |
638f5b90 | 771 | */ |
fd978bf7 JS |
772 | static int realloc_func_state(struct bpf_func_state *state, int stack_size, |
773 | int refs_size, bool copy_old) | |
638f5b90 | 774 | { |
fd978bf7 JS |
775 | int err = realloc_reference_state(state, refs_size, copy_old); |
776 | if (err) | |
777 | return err; | |
778 | return realloc_stack_state(state, stack_size, copy_old); | |
779 | } | |
780 | ||
781 | /* Acquire a pointer id from the env and update the state->refs to include | |
782 | * this new pointer reference. | |
783 | * On success, returns a valid pointer id to associate with the register | |
784 | * On failure, returns a negative errno. | |
638f5b90 | 785 | */ |
fd978bf7 | 786 | static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx) |
638f5b90 | 787 | { |
fd978bf7 JS |
788 | struct bpf_func_state *state = cur_func(env); |
789 | int new_ofs = state->acquired_refs; | |
790 | int id, err; | |
791 | ||
792 | err = realloc_reference_state(state, state->acquired_refs + 1, true); | |
793 | if (err) | |
794 | return err; | |
795 | id = ++env->id_gen; | |
796 | state->refs[new_ofs].id = id; | |
797 | state->refs[new_ofs].insn_idx = insn_idx; | |
638f5b90 | 798 | |
fd978bf7 JS |
799 | return id; |
800 | } | |
801 | ||
802 | /* release function corresponding to acquire_reference_state(). Idempotent. */ | |
46f8bc92 | 803 | static int release_reference_state(struct bpf_func_state *state, int ptr_id) |
fd978bf7 JS |
804 | { |
805 | int i, last_idx; | |
806 | ||
fd978bf7 JS |
807 | last_idx = state->acquired_refs - 1; |
808 | for (i = 0; i < state->acquired_refs; i++) { | |
809 | if (state->refs[i].id == ptr_id) { | |
810 | if (last_idx && i != last_idx) | |
811 | memcpy(&state->refs[i], &state->refs[last_idx], | |
812 | sizeof(*state->refs)); | |
813 | memset(&state->refs[last_idx], 0, sizeof(*state->refs)); | |
814 | state->acquired_refs--; | |
638f5b90 | 815 | return 0; |
638f5b90 | 816 | } |
638f5b90 | 817 | } |
46f8bc92 | 818 | return -EINVAL; |
fd978bf7 JS |
819 | } |
820 | ||
821 | static int transfer_reference_state(struct bpf_func_state *dst, | |
822 | struct bpf_func_state *src) | |
823 | { | |
824 | int err = realloc_reference_state(dst, src->acquired_refs, false); | |
825 | if (err) | |
826 | return err; | |
827 | err = copy_reference_state(dst, src); | |
828 | if (err) | |
829 | return err; | |
638f5b90 AS |
830 | return 0; |
831 | } | |
832 | ||
f4d7e40a AS |
833 | static void free_func_state(struct bpf_func_state *state) |
834 | { | |
5896351e AS |
835 | if (!state) |
836 | return; | |
fd978bf7 | 837 | kfree(state->refs); |
f4d7e40a AS |
838 | kfree(state->stack); |
839 | kfree(state); | |
840 | } | |
841 | ||
b5dc0163 AS |
842 | static void clear_jmp_history(struct bpf_verifier_state *state) |
843 | { | |
844 | kfree(state->jmp_history); | |
845 | state->jmp_history = NULL; | |
846 | state->jmp_history_cnt = 0; | |
847 | } | |
848 | ||
1969db47 AS |
849 | static void free_verifier_state(struct bpf_verifier_state *state, |
850 | bool free_self) | |
638f5b90 | 851 | { |
f4d7e40a AS |
852 | int i; |
853 | ||
854 | for (i = 0; i <= state->curframe; i++) { | |
855 | free_func_state(state->frame[i]); | |
856 | state->frame[i] = NULL; | |
857 | } | |
b5dc0163 | 858 | clear_jmp_history(state); |
1969db47 AS |
859 | if (free_self) |
860 | kfree(state); | |
638f5b90 AS |
861 | } |
862 | ||
863 | /* copy verifier state from src to dst growing dst stack space | |
864 | * when necessary to accommodate larger src stack | |
865 | */ | |
f4d7e40a AS |
866 | static int copy_func_state(struct bpf_func_state *dst, |
867 | const struct bpf_func_state *src) | |
638f5b90 AS |
868 | { |
869 | int err; | |
870 | ||
fd978bf7 JS |
871 | err = realloc_func_state(dst, src->allocated_stack, src->acquired_refs, |
872 | false); | |
873 | if (err) | |
874 | return err; | |
875 | memcpy(dst, src, offsetof(struct bpf_func_state, acquired_refs)); | |
876 | err = copy_reference_state(dst, src); | |
638f5b90 AS |
877 | if (err) |
878 | return err; | |
638f5b90 AS |
879 | return copy_stack_state(dst, src); |
880 | } | |
881 | ||
f4d7e40a AS |
882 | static int copy_verifier_state(struct bpf_verifier_state *dst_state, |
883 | const struct bpf_verifier_state *src) | |
884 | { | |
885 | struct bpf_func_state *dst; | |
b5dc0163 | 886 | u32 jmp_sz = sizeof(struct bpf_idx_pair) * src->jmp_history_cnt; |
f4d7e40a AS |
887 | int i, err; |
888 | ||
b5dc0163 AS |
889 | if (dst_state->jmp_history_cnt < src->jmp_history_cnt) { |
890 | kfree(dst_state->jmp_history); | |
891 | dst_state->jmp_history = kmalloc(jmp_sz, GFP_USER); | |
892 | if (!dst_state->jmp_history) | |
893 | return -ENOMEM; | |
894 | } | |
895 | memcpy(dst_state->jmp_history, src->jmp_history, jmp_sz); | |
896 | dst_state->jmp_history_cnt = src->jmp_history_cnt; | |
897 | ||
f4d7e40a AS |
898 | /* if dst has more stack frames then src frame, free them */ |
899 | for (i = src->curframe + 1; i <= dst_state->curframe; i++) { | |
900 | free_func_state(dst_state->frame[i]); | |
901 | dst_state->frame[i] = NULL; | |
902 | } | |
979d63d5 | 903 | dst_state->speculative = src->speculative; |
f4d7e40a | 904 | dst_state->curframe = src->curframe; |
d83525ca | 905 | dst_state->active_spin_lock = src->active_spin_lock; |
2589726d AS |
906 | dst_state->branches = src->branches; |
907 | dst_state->parent = src->parent; | |
b5dc0163 AS |
908 | dst_state->first_insn_idx = src->first_insn_idx; |
909 | dst_state->last_insn_idx = src->last_insn_idx; | |
f4d7e40a AS |
910 | for (i = 0; i <= src->curframe; i++) { |
911 | dst = dst_state->frame[i]; | |
912 | if (!dst) { | |
913 | dst = kzalloc(sizeof(*dst), GFP_KERNEL); | |
914 | if (!dst) | |
915 | return -ENOMEM; | |
916 | dst_state->frame[i] = dst; | |
917 | } | |
918 | err = copy_func_state(dst, src->frame[i]); | |
919 | if (err) | |
920 | return err; | |
921 | } | |
922 | return 0; | |
923 | } | |
924 | ||
2589726d AS |
925 | static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st) |
926 | { | |
927 | while (st) { | |
928 | u32 br = --st->branches; | |
929 | ||
930 | /* WARN_ON(br > 1) technically makes sense here, | |
931 | * but see comment in push_stack(), hence: | |
932 | */ | |
933 | WARN_ONCE((int)br < 0, | |
934 | "BUG update_branch_counts:branches_to_explore=%d\n", | |
935 | br); | |
936 | if (br) | |
937 | break; | |
938 | st = st->parent; | |
939 | } | |
940 | } | |
941 | ||
638f5b90 | 942 | static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx, |
6f8a57cc | 943 | int *insn_idx, bool pop_log) |
638f5b90 AS |
944 | { |
945 | struct bpf_verifier_state *cur = env->cur_state; | |
946 | struct bpf_verifier_stack_elem *elem, *head = env->head; | |
947 | int err; | |
17a52670 AS |
948 | |
949 | if (env->head == NULL) | |
638f5b90 | 950 | return -ENOENT; |
17a52670 | 951 | |
638f5b90 AS |
952 | if (cur) { |
953 | err = copy_verifier_state(cur, &head->st); | |
954 | if (err) | |
955 | return err; | |
956 | } | |
6f8a57cc AN |
957 | if (pop_log) |
958 | bpf_vlog_reset(&env->log, head->log_pos); | |
638f5b90 AS |
959 | if (insn_idx) |
960 | *insn_idx = head->insn_idx; | |
17a52670 | 961 | if (prev_insn_idx) |
638f5b90 AS |
962 | *prev_insn_idx = head->prev_insn_idx; |
963 | elem = head->next; | |
1969db47 | 964 | free_verifier_state(&head->st, false); |
638f5b90 | 965 | kfree(head); |
17a52670 AS |
966 | env->head = elem; |
967 | env->stack_size--; | |
638f5b90 | 968 | return 0; |
17a52670 AS |
969 | } |
970 | ||
58e2af8b | 971 | static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env, |
979d63d5 DB |
972 | int insn_idx, int prev_insn_idx, |
973 | bool speculative) | |
17a52670 | 974 | { |
638f5b90 | 975 | struct bpf_verifier_state *cur = env->cur_state; |
58e2af8b | 976 | struct bpf_verifier_stack_elem *elem; |
638f5b90 | 977 | int err; |
17a52670 | 978 | |
638f5b90 | 979 | elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL); |
17a52670 AS |
980 | if (!elem) |
981 | goto err; | |
982 | ||
17a52670 AS |
983 | elem->insn_idx = insn_idx; |
984 | elem->prev_insn_idx = prev_insn_idx; | |
985 | elem->next = env->head; | |
6f8a57cc | 986 | elem->log_pos = env->log.len_used; |
17a52670 AS |
987 | env->head = elem; |
988 | env->stack_size++; | |
1969db47 AS |
989 | err = copy_verifier_state(&elem->st, cur); |
990 | if (err) | |
991 | goto err; | |
979d63d5 | 992 | elem->st.speculative |= speculative; |
b285fcb7 AS |
993 | if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) { |
994 | verbose(env, "The sequence of %d jumps is too complex.\n", | |
995 | env->stack_size); | |
17a52670 AS |
996 | goto err; |
997 | } | |
2589726d AS |
998 | if (elem->st.parent) { |
999 | ++elem->st.parent->branches; | |
1000 | /* WARN_ON(branches > 2) technically makes sense here, | |
1001 | * but | |
1002 | * 1. speculative states will bump 'branches' for non-branch | |
1003 | * instructions | |
1004 | * 2. is_state_visited() heuristics may decide not to create | |
1005 | * a new state for a sequence of branches and all such current | |
1006 | * and cloned states will be pointing to a single parent state | |
1007 | * which might have large 'branches' count. | |
1008 | */ | |
1009 | } | |
17a52670 AS |
1010 | return &elem->st; |
1011 | err: | |
5896351e AS |
1012 | free_verifier_state(env->cur_state, true); |
1013 | env->cur_state = NULL; | |
17a52670 | 1014 | /* pop all elements and return */ |
6f8a57cc | 1015 | while (!pop_stack(env, NULL, NULL, false)); |
17a52670 AS |
1016 | return NULL; |
1017 | } | |
1018 | ||
1019 | #define CALLER_SAVED_REGS 6 | |
1020 | static const int caller_saved[CALLER_SAVED_REGS] = { | |
1021 | BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5 | |
1022 | }; | |
1023 | ||
f54c7898 DB |
1024 | static void __mark_reg_not_init(const struct bpf_verifier_env *env, |
1025 | struct bpf_reg_state *reg); | |
f1174f77 | 1026 | |
e688c3db AS |
1027 | /* This helper doesn't clear reg->id */ |
1028 | static void ___mark_reg_known(struct bpf_reg_state *reg, u64 imm) | |
b03c9f9f | 1029 | { |
b03c9f9f EC |
1030 | reg->var_off = tnum_const(imm); |
1031 | reg->smin_value = (s64)imm; | |
1032 | reg->smax_value = (s64)imm; | |
1033 | reg->umin_value = imm; | |
1034 | reg->umax_value = imm; | |
3f50f132 JF |
1035 | |
1036 | reg->s32_min_value = (s32)imm; | |
1037 | reg->s32_max_value = (s32)imm; | |
1038 | reg->u32_min_value = (u32)imm; | |
1039 | reg->u32_max_value = (u32)imm; | |
1040 | } | |
1041 | ||
e688c3db AS |
1042 | /* Mark the unknown part of a register (variable offset or scalar value) as |
1043 | * known to have the value @imm. | |
1044 | */ | |
1045 | static void __mark_reg_known(struct bpf_reg_state *reg, u64 imm) | |
1046 | { | |
1047 | /* Clear id, off, and union(map_ptr, range) */ | |
1048 | memset(((u8 *)reg) + sizeof(reg->type), 0, | |
1049 | offsetof(struct bpf_reg_state, var_off) - sizeof(reg->type)); | |
1050 | ___mark_reg_known(reg, imm); | |
1051 | } | |
1052 | ||
3f50f132 JF |
1053 | static void __mark_reg32_known(struct bpf_reg_state *reg, u64 imm) |
1054 | { | |
1055 | reg->var_off = tnum_const_subreg(reg->var_off, imm); | |
1056 | reg->s32_min_value = (s32)imm; | |
1057 | reg->s32_max_value = (s32)imm; | |
1058 | reg->u32_min_value = (u32)imm; | |
1059 | reg->u32_max_value = (u32)imm; | |
b03c9f9f EC |
1060 | } |
1061 | ||
f1174f77 EC |
1062 | /* Mark the 'variable offset' part of a register as zero. This should be |
1063 | * used only on registers holding a pointer type. | |
1064 | */ | |
1065 | static void __mark_reg_known_zero(struct bpf_reg_state *reg) | |
a9789ef9 | 1066 | { |
b03c9f9f | 1067 | __mark_reg_known(reg, 0); |
f1174f77 | 1068 | } |
a9789ef9 | 1069 | |
cc2b14d5 AS |
1070 | static void __mark_reg_const_zero(struct bpf_reg_state *reg) |
1071 | { | |
1072 | __mark_reg_known(reg, 0); | |
cc2b14d5 AS |
1073 | reg->type = SCALAR_VALUE; |
1074 | } | |
1075 | ||
61bd5218 JK |
1076 | static void mark_reg_known_zero(struct bpf_verifier_env *env, |
1077 | struct bpf_reg_state *regs, u32 regno) | |
f1174f77 EC |
1078 | { |
1079 | if (WARN_ON(regno >= MAX_BPF_REG)) { | |
61bd5218 | 1080 | verbose(env, "mark_reg_known_zero(regs, %u)\n", regno); |
f1174f77 EC |
1081 | /* Something bad happened, let's kill all regs */ |
1082 | for (regno = 0; regno < MAX_BPF_REG; regno++) | |
f54c7898 | 1083 | __mark_reg_not_init(env, regs + regno); |
f1174f77 EC |
1084 | return; |
1085 | } | |
1086 | __mark_reg_known_zero(regs + regno); | |
1087 | } | |
1088 | ||
4ddb7416 DB |
1089 | static void mark_ptr_not_null_reg(struct bpf_reg_state *reg) |
1090 | { | |
1091 | switch (reg->type) { | |
1092 | case PTR_TO_MAP_VALUE_OR_NULL: { | |
1093 | const struct bpf_map *map = reg->map_ptr; | |
1094 | ||
1095 | if (map->inner_map_meta) { | |
1096 | reg->type = CONST_PTR_TO_MAP; | |
1097 | reg->map_ptr = map->inner_map_meta; | |
1098 | } else if (map->map_type == BPF_MAP_TYPE_XSKMAP) { | |
1099 | reg->type = PTR_TO_XDP_SOCK; | |
1100 | } else if (map->map_type == BPF_MAP_TYPE_SOCKMAP || | |
1101 | map->map_type == BPF_MAP_TYPE_SOCKHASH) { | |
1102 | reg->type = PTR_TO_SOCKET; | |
1103 | } else { | |
1104 | reg->type = PTR_TO_MAP_VALUE; | |
1105 | } | |
1106 | break; | |
1107 | } | |
1108 | case PTR_TO_SOCKET_OR_NULL: | |
1109 | reg->type = PTR_TO_SOCKET; | |
1110 | break; | |
1111 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
1112 | reg->type = PTR_TO_SOCK_COMMON; | |
1113 | break; | |
1114 | case PTR_TO_TCP_SOCK_OR_NULL: | |
1115 | reg->type = PTR_TO_TCP_SOCK; | |
1116 | break; | |
1117 | case PTR_TO_BTF_ID_OR_NULL: | |
1118 | reg->type = PTR_TO_BTF_ID; | |
1119 | break; | |
1120 | case PTR_TO_MEM_OR_NULL: | |
1121 | reg->type = PTR_TO_MEM; | |
1122 | break; | |
1123 | case PTR_TO_RDONLY_BUF_OR_NULL: | |
1124 | reg->type = PTR_TO_RDONLY_BUF; | |
1125 | break; | |
1126 | case PTR_TO_RDWR_BUF_OR_NULL: | |
1127 | reg->type = PTR_TO_RDWR_BUF; | |
1128 | break; | |
1129 | default: | |
33ccec5f | 1130 | WARN_ONCE(1, "unknown nullable register type"); |
4ddb7416 DB |
1131 | } |
1132 | } | |
1133 | ||
de8f3a83 DB |
1134 | static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg) |
1135 | { | |
1136 | return type_is_pkt_pointer(reg->type); | |
1137 | } | |
1138 | ||
1139 | static bool reg_is_pkt_pointer_any(const struct bpf_reg_state *reg) | |
1140 | { | |
1141 | return reg_is_pkt_pointer(reg) || | |
1142 | reg->type == PTR_TO_PACKET_END; | |
1143 | } | |
1144 | ||
1145 | /* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */ | |
1146 | static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg, | |
1147 | enum bpf_reg_type which) | |
1148 | { | |
1149 | /* The register can already have a range from prior markings. | |
1150 | * This is fine as long as it hasn't been advanced from its | |
1151 | * origin. | |
1152 | */ | |
1153 | return reg->type == which && | |
1154 | reg->id == 0 && | |
1155 | reg->off == 0 && | |
1156 | tnum_equals_const(reg->var_off, 0); | |
1157 | } | |
1158 | ||
3f50f132 JF |
1159 | /* Reset the min/max bounds of a register */ |
1160 | static void __mark_reg_unbounded(struct bpf_reg_state *reg) | |
1161 | { | |
1162 | reg->smin_value = S64_MIN; | |
1163 | reg->smax_value = S64_MAX; | |
1164 | reg->umin_value = 0; | |
1165 | reg->umax_value = U64_MAX; | |
1166 | ||
1167 | reg->s32_min_value = S32_MIN; | |
1168 | reg->s32_max_value = S32_MAX; | |
1169 | reg->u32_min_value = 0; | |
1170 | reg->u32_max_value = U32_MAX; | |
1171 | } | |
1172 | ||
1173 | static void __mark_reg64_unbounded(struct bpf_reg_state *reg) | |
1174 | { | |
1175 | reg->smin_value = S64_MIN; | |
1176 | reg->smax_value = S64_MAX; | |
1177 | reg->umin_value = 0; | |
1178 | reg->umax_value = U64_MAX; | |
1179 | } | |
1180 | ||
1181 | static void __mark_reg32_unbounded(struct bpf_reg_state *reg) | |
1182 | { | |
1183 | reg->s32_min_value = S32_MIN; | |
1184 | reg->s32_max_value = S32_MAX; | |
1185 | reg->u32_min_value = 0; | |
1186 | reg->u32_max_value = U32_MAX; | |
1187 | } | |
1188 | ||
1189 | static void __update_reg32_bounds(struct bpf_reg_state *reg) | |
1190 | { | |
1191 | struct tnum var32_off = tnum_subreg(reg->var_off); | |
1192 | ||
1193 | /* min signed is max(sign bit) | min(other bits) */ | |
1194 | reg->s32_min_value = max_t(s32, reg->s32_min_value, | |
1195 | var32_off.value | (var32_off.mask & S32_MIN)); | |
1196 | /* max signed is min(sign bit) | max(other bits) */ | |
1197 | reg->s32_max_value = min_t(s32, reg->s32_max_value, | |
1198 | var32_off.value | (var32_off.mask & S32_MAX)); | |
1199 | reg->u32_min_value = max_t(u32, reg->u32_min_value, (u32)var32_off.value); | |
1200 | reg->u32_max_value = min(reg->u32_max_value, | |
1201 | (u32)(var32_off.value | var32_off.mask)); | |
1202 | } | |
1203 | ||
1204 | static void __update_reg64_bounds(struct bpf_reg_state *reg) | |
b03c9f9f EC |
1205 | { |
1206 | /* min signed is max(sign bit) | min(other bits) */ | |
1207 | reg->smin_value = max_t(s64, reg->smin_value, | |
1208 | reg->var_off.value | (reg->var_off.mask & S64_MIN)); | |
1209 | /* max signed is min(sign bit) | max(other bits) */ | |
1210 | reg->smax_value = min_t(s64, reg->smax_value, | |
1211 | reg->var_off.value | (reg->var_off.mask & S64_MAX)); | |
1212 | reg->umin_value = max(reg->umin_value, reg->var_off.value); | |
1213 | reg->umax_value = min(reg->umax_value, | |
1214 | reg->var_off.value | reg->var_off.mask); | |
1215 | } | |
1216 | ||
3f50f132 JF |
1217 | static void __update_reg_bounds(struct bpf_reg_state *reg) |
1218 | { | |
1219 | __update_reg32_bounds(reg); | |
1220 | __update_reg64_bounds(reg); | |
1221 | } | |
1222 | ||
b03c9f9f | 1223 | /* Uses signed min/max values to inform unsigned, and vice-versa */ |
3f50f132 JF |
1224 | static void __reg32_deduce_bounds(struct bpf_reg_state *reg) |
1225 | { | |
1226 | /* Learn sign from signed bounds. | |
1227 | * If we cannot cross the sign boundary, then signed and unsigned bounds | |
1228 | * are the same, so combine. This works even in the negative case, e.g. | |
1229 | * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff. | |
1230 | */ | |
1231 | if (reg->s32_min_value >= 0 || reg->s32_max_value < 0) { | |
1232 | reg->s32_min_value = reg->u32_min_value = | |
1233 | max_t(u32, reg->s32_min_value, reg->u32_min_value); | |
1234 | reg->s32_max_value = reg->u32_max_value = | |
1235 | min_t(u32, reg->s32_max_value, reg->u32_max_value); | |
1236 | return; | |
1237 | } | |
1238 | /* Learn sign from unsigned bounds. Signed bounds cross the sign | |
1239 | * boundary, so we must be careful. | |
1240 | */ | |
1241 | if ((s32)reg->u32_max_value >= 0) { | |
1242 | /* Positive. We can't learn anything from the smin, but smax | |
1243 | * is positive, hence safe. | |
1244 | */ | |
1245 | reg->s32_min_value = reg->u32_min_value; | |
1246 | reg->s32_max_value = reg->u32_max_value = | |
1247 | min_t(u32, reg->s32_max_value, reg->u32_max_value); | |
1248 | } else if ((s32)reg->u32_min_value < 0) { | |
1249 | /* Negative. We can't learn anything from the smax, but smin | |
1250 | * is negative, hence safe. | |
1251 | */ | |
1252 | reg->s32_min_value = reg->u32_min_value = | |
1253 | max_t(u32, reg->s32_min_value, reg->u32_min_value); | |
1254 | reg->s32_max_value = reg->u32_max_value; | |
1255 | } | |
1256 | } | |
1257 | ||
1258 | static void __reg64_deduce_bounds(struct bpf_reg_state *reg) | |
b03c9f9f EC |
1259 | { |
1260 | /* Learn sign from signed bounds. | |
1261 | * If we cannot cross the sign boundary, then signed and unsigned bounds | |
1262 | * are the same, so combine. This works even in the negative case, e.g. | |
1263 | * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff. | |
1264 | */ | |
1265 | if (reg->smin_value >= 0 || reg->smax_value < 0) { | |
1266 | reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value, | |
1267 | reg->umin_value); | |
1268 | reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value, | |
1269 | reg->umax_value); | |
1270 | return; | |
1271 | } | |
1272 | /* Learn sign from unsigned bounds. Signed bounds cross the sign | |
1273 | * boundary, so we must be careful. | |
1274 | */ | |
1275 | if ((s64)reg->umax_value >= 0) { | |
1276 | /* Positive. We can't learn anything from the smin, but smax | |
1277 | * is positive, hence safe. | |
1278 | */ | |
1279 | reg->smin_value = reg->umin_value; | |
1280 | reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value, | |
1281 | reg->umax_value); | |
1282 | } else if ((s64)reg->umin_value < 0) { | |
1283 | /* Negative. We can't learn anything from the smax, but smin | |
1284 | * is negative, hence safe. | |
1285 | */ | |
1286 | reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value, | |
1287 | reg->umin_value); | |
1288 | reg->smax_value = reg->umax_value; | |
1289 | } | |
1290 | } | |
1291 | ||
3f50f132 JF |
1292 | static void __reg_deduce_bounds(struct bpf_reg_state *reg) |
1293 | { | |
1294 | __reg32_deduce_bounds(reg); | |
1295 | __reg64_deduce_bounds(reg); | |
1296 | } | |
1297 | ||
b03c9f9f EC |
1298 | /* Attempts to improve var_off based on unsigned min/max information */ |
1299 | static void __reg_bound_offset(struct bpf_reg_state *reg) | |
1300 | { | |
3f50f132 JF |
1301 | struct tnum var64_off = tnum_intersect(reg->var_off, |
1302 | tnum_range(reg->umin_value, | |
1303 | reg->umax_value)); | |
1304 | struct tnum var32_off = tnum_intersect(tnum_subreg(reg->var_off), | |
1305 | tnum_range(reg->u32_min_value, | |
1306 | reg->u32_max_value)); | |
1307 | ||
1308 | reg->var_off = tnum_or(tnum_clear_subreg(var64_off), var32_off); | |
b03c9f9f EC |
1309 | } |
1310 | ||
3f50f132 | 1311 | static void __reg_assign_32_into_64(struct bpf_reg_state *reg) |
b03c9f9f | 1312 | { |
3f50f132 JF |
1313 | reg->umin_value = reg->u32_min_value; |
1314 | reg->umax_value = reg->u32_max_value; | |
1315 | /* Attempt to pull 32-bit signed bounds into 64-bit bounds | |
1316 | * but must be positive otherwise set to worse case bounds | |
1317 | * and refine later from tnum. | |
1318 | */ | |
3a71dc36 | 1319 | if (reg->s32_min_value >= 0 && reg->s32_max_value >= 0) |
3f50f132 JF |
1320 | reg->smax_value = reg->s32_max_value; |
1321 | else | |
1322 | reg->smax_value = U32_MAX; | |
3a71dc36 JF |
1323 | if (reg->s32_min_value >= 0) |
1324 | reg->smin_value = reg->s32_min_value; | |
1325 | else | |
1326 | reg->smin_value = 0; | |
3f50f132 JF |
1327 | } |
1328 | ||
1329 | static void __reg_combine_32_into_64(struct bpf_reg_state *reg) | |
1330 | { | |
1331 | /* special case when 64-bit register has upper 32-bit register | |
1332 | * zeroed. Typically happens after zext or <<32, >>32 sequence | |
1333 | * allowing us to use 32-bit bounds directly, | |
1334 | */ | |
1335 | if (tnum_equals_const(tnum_clear_subreg(reg->var_off), 0)) { | |
1336 | __reg_assign_32_into_64(reg); | |
1337 | } else { | |
1338 | /* Otherwise the best we can do is push lower 32bit known and | |
1339 | * unknown bits into register (var_off set from jmp logic) | |
1340 | * then learn as much as possible from the 64-bit tnum | |
1341 | * known and unknown bits. The previous smin/smax bounds are | |
1342 | * invalid here because of jmp32 compare so mark them unknown | |
1343 | * so they do not impact tnum bounds calculation. | |
1344 | */ | |
1345 | __mark_reg64_unbounded(reg); | |
1346 | __update_reg_bounds(reg); | |
1347 | } | |
1348 | ||
1349 | /* Intersecting with the old var_off might have improved our bounds | |
1350 | * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), | |
1351 | * then new var_off is (0; 0x7f...fc) which improves our umax. | |
1352 | */ | |
1353 | __reg_deduce_bounds(reg); | |
1354 | __reg_bound_offset(reg); | |
1355 | __update_reg_bounds(reg); | |
1356 | } | |
1357 | ||
1358 | static bool __reg64_bound_s32(s64 a) | |
1359 | { | |
b0270958 | 1360 | return a > S32_MIN && a < S32_MAX; |
3f50f132 JF |
1361 | } |
1362 | ||
1363 | static bool __reg64_bound_u32(u64 a) | |
1364 | { | |
1365 | if (a > U32_MIN && a < U32_MAX) | |
1366 | return true; | |
1367 | return false; | |
1368 | } | |
1369 | ||
1370 | static void __reg_combine_64_into_32(struct bpf_reg_state *reg) | |
1371 | { | |
1372 | __mark_reg32_unbounded(reg); | |
1373 | ||
b0270958 | 1374 | if (__reg64_bound_s32(reg->smin_value) && __reg64_bound_s32(reg->smax_value)) { |
3f50f132 | 1375 | reg->s32_min_value = (s32)reg->smin_value; |
3f50f132 | 1376 | reg->s32_max_value = (s32)reg->smax_value; |
b0270958 | 1377 | } |
3f50f132 JF |
1378 | if (__reg64_bound_u32(reg->umin_value)) |
1379 | reg->u32_min_value = (u32)reg->umin_value; | |
1380 | if (__reg64_bound_u32(reg->umax_value)) | |
1381 | reg->u32_max_value = (u32)reg->umax_value; | |
1382 | ||
1383 | /* Intersecting with the old var_off might have improved our bounds | |
1384 | * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), | |
1385 | * then new var_off is (0; 0x7f...fc) which improves our umax. | |
1386 | */ | |
1387 | __reg_deduce_bounds(reg); | |
1388 | __reg_bound_offset(reg); | |
1389 | __update_reg_bounds(reg); | |
b03c9f9f EC |
1390 | } |
1391 | ||
f1174f77 | 1392 | /* Mark a register as having a completely unknown (scalar) value. */ |
f54c7898 DB |
1393 | static void __mark_reg_unknown(const struct bpf_verifier_env *env, |
1394 | struct bpf_reg_state *reg) | |
f1174f77 | 1395 | { |
a9c676bc AS |
1396 | /* |
1397 | * Clear type, id, off, and union(map_ptr, range) and | |
1398 | * padding between 'type' and union | |
1399 | */ | |
1400 | memset(reg, 0, offsetof(struct bpf_reg_state, var_off)); | |
f1174f77 | 1401 | reg->type = SCALAR_VALUE; |
f1174f77 | 1402 | reg->var_off = tnum_unknown; |
f4d7e40a | 1403 | reg->frameno = 0; |
2c78ee89 | 1404 | reg->precise = env->subprog_cnt > 1 || !env->bpf_capable; |
b03c9f9f | 1405 | __mark_reg_unbounded(reg); |
f1174f77 EC |
1406 | } |
1407 | ||
61bd5218 JK |
1408 | static void mark_reg_unknown(struct bpf_verifier_env *env, |
1409 | struct bpf_reg_state *regs, u32 regno) | |
f1174f77 EC |
1410 | { |
1411 | if (WARN_ON(regno >= MAX_BPF_REG)) { | |
61bd5218 | 1412 | verbose(env, "mark_reg_unknown(regs, %u)\n", regno); |
19ceb417 AS |
1413 | /* Something bad happened, let's kill all regs except FP */ |
1414 | for (regno = 0; regno < BPF_REG_FP; regno++) | |
f54c7898 | 1415 | __mark_reg_not_init(env, regs + regno); |
f1174f77 EC |
1416 | return; |
1417 | } | |
f54c7898 | 1418 | __mark_reg_unknown(env, regs + regno); |
f1174f77 EC |
1419 | } |
1420 | ||
f54c7898 DB |
1421 | static void __mark_reg_not_init(const struct bpf_verifier_env *env, |
1422 | struct bpf_reg_state *reg) | |
f1174f77 | 1423 | { |
f54c7898 | 1424 | __mark_reg_unknown(env, reg); |
f1174f77 EC |
1425 | reg->type = NOT_INIT; |
1426 | } | |
1427 | ||
61bd5218 JK |
1428 | static void mark_reg_not_init(struct bpf_verifier_env *env, |
1429 | struct bpf_reg_state *regs, u32 regno) | |
f1174f77 EC |
1430 | { |
1431 | if (WARN_ON(regno >= MAX_BPF_REG)) { | |
61bd5218 | 1432 | verbose(env, "mark_reg_not_init(regs, %u)\n", regno); |
19ceb417 AS |
1433 | /* Something bad happened, let's kill all regs except FP */ |
1434 | for (regno = 0; regno < BPF_REG_FP; regno++) | |
f54c7898 | 1435 | __mark_reg_not_init(env, regs + regno); |
f1174f77 EC |
1436 | return; |
1437 | } | |
f54c7898 | 1438 | __mark_reg_not_init(env, regs + regno); |
a9789ef9 DB |
1439 | } |
1440 | ||
41c48f3a AI |
1441 | static void mark_btf_ld_reg(struct bpf_verifier_env *env, |
1442 | struct bpf_reg_state *regs, u32 regno, | |
22dc4a0f AN |
1443 | enum bpf_reg_type reg_type, |
1444 | struct btf *btf, u32 btf_id) | |
41c48f3a AI |
1445 | { |
1446 | if (reg_type == SCALAR_VALUE) { | |
1447 | mark_reg_unknown(env, regs, regno); | |
1448 | return; | |
1449 | } | |
1450 | mark_reg_known_zero(env, regs, regno); | |
1451 | regs[regno].type = PTR_TO_BTF_ID; | |
22dc4a0f | 1452 | regs[regno].btf = btf; |
41c48f3a AI |
1453 | regs[regno].btf_id = btf_id; |
1454 | } | |
1455 | ||
5327ed3d | 1456 | #define DEF_NOT_SUBREG (0) |
61bd5218 | 1457 | static void init_reg_state(struct bpf_verifier_env *env, |
f4d7e40a | 1458 | struct bpf_func_state *state) |
17a52670 | 1459 | { |
f4d7e40a | 1460 | struct bpf_reg_state *regs = state->regs; |
17a52670 AS |
1461 | int i; |
1462 | ||
dc503a8a | 1463 | for (i = 0; i < MAX_BPF_REG; i++) { |
61bd5218 | 1464 | mark_reg_not_init(env, regs, i); |
dc503a8a | 1465 | regs[i].live = REG_LIVE_NONE; |
679c782d | 1466 | regs[i].parent = NULL; |
5327ed3d | 1467 | regs[i].subreg_def = DEF_NOT_SUBREG; |
dc503a8a | 1468 | } |
17a52670 AS |
1469 | |
1470 | /* frame pointer */ | |
f1174f77 | 1471 | regs[BPF_REG_FP].type = PTR_TO_STACK; |
61bd5218 | 1472 | mark_reg_known_zero(env, regs, BPF_REG_FP); |
f4d7e40a | 1473 | regs[BPF_REG_FP].frameno = state->frameno; |
6760bf2d DB |
1474 | } |
1475 | ||
f4d7e40a AS |
1476 | #define BPF_MAIN_FUNC (-1) |
1477 | static void init_func_state(struct bpf_verifier_env *env, | |
1478 | struct bpf_func_state *state, | |
1479 | int callsite, int frameno, int subprogno) | |
1480 | { | |
1481 | state->callsite = callsite; | |
1482 | state->frameno = frameno; | |
1483 | state->subprogno = subprogno; | |
1484 | init_reg_state(env, state); | |
1485 | } | |
1486 | ||
17a52670 AS |
1487 | enum reg_arg_type { |
1488 | SRC_OP, /* register is used as source operand */ | |
1489 | DST_OP, /* register is used as destination operand */ | |
1490 | DST_OP_NO_MARK /* same as above, check only, don't mark */ | |
1491 | }; | |
1492 | ||
cc8b0b92 AS |
1493 | static int cmp_subprogs(const void *a, const void *b) |
1494 | { | |
9c8105bd JW |
1495 | return ((struct bpf_subprog_info *)a)->start - |
1496 | ((struct bpf_subprog_info *)b)->start; | |
cc8b0b92 AS |
1497 | } |
1498 | ||
1499 | static int find_subprog(struct bpf_verifier_env *env, int off) | |
1500 | { | |
9c8105bd | 1501 | struct bpf_subprog_info *p; |
cc8b0b92 | 1502 | |
9c8105bd JW |
1503 | p = bsearch(&off, env->subprog_info, env->subprog_cnt, |
1504 | sizeof(env->subprog_info[0]), cmp_subprogs); | |
cc8b0b92 AS |
1505 | if (!p) |
1506 | return -ENOENT; | |
9c8105bd | 1507 | return p - env->subprog_info; |
cc8b0b92 AS |
1508 | |
1509 | } | |
1510 | ||
1511 | static int add_subprog(struct bpf_verifier_env *env, int off) | |
1512 | { | |
1513 | int insn_cnt = env->prog->len; | |
1514 | int ret; | |
1515 | ||
1516 | if (off >= insn_cnt || off < 0) { | |
1517 | verbose(env, "call to invalid destination\n"); | |
1518 | return -EINVAL; | |
1519 | } | |
1520 | ret = find_subprog(env, off); | |
1521 | if (ret >= 0) | |
1522 | return 0; | |
4cb3d99c | 1523 | if (env->subprog_cnt >= BPF_MAX_SUBPROGS) { |
cc8b0b92 AS |
1524 | verbose(env, "too many subprograms\n"); |
1525 | return -E2BIG; | |
1526 | } | |
9c8105bd JW |
1527 | env->subprog_info[env->subprog_cnt++].start = off; |
1528 | sort(env->subprog_info, env->subprog_cnt, | |
1529 | sizeof(env->subprog_info[0]), cmp_subprogs, NULL); | |
cc8b0b92 AS |
1530 | return 0; |
1531 | } | |
1532 | ||
1533 | static int check_subprogs(struct bpf_verifier_env *env) | |
1534 | { | |
1535 | int i, ret, subprog_start, subprog_end, off, cur_subprog = 0; | |
9c8105bd | 1536 | struct bpf_subprog_info *subprog = env->subprog_info; |
cc8b0b92 AS |
1537 | struct bpf_insn *insn = env->prog->insnsi; |
1538 | int insn_cnt = env->prog->len; | |
1539 | ||
f910cefa JW |
1540 | /* Add entry function. */ |
1541 | ret = add_subprog(env, 0); | |
1542 | if (ret < 0) | |
1543 | return ret; | |
1544 | ||
cc8b0b92 AS |
1545 | /* determine subprog starts. The end is one before the next starts */ |
1546 | for (i = 0; i < insn_cnt; i++) { | |
23a2d70c | 1547 | if (!bpf_pseudo_call(insn + i)) |
cc8b0b92 | 1548 | continue; |
2c78ee89 AS |
1549 | if (!env->bpf_capable) { |
1550 | verbose(env, | |
1551 | "function calls to other bpf functions are allowed for CAP_BPF and CAP_SYS_ADMIN\n"); | |
cc8b0b92 AS |
1552 | return -EPERM; |
1553 | } | |
cc8b0b92 AS |
1554 | ret = add_subprog(env, i + insn[i].imm + 1); |
1555 | if (ret < 0) | |
1556 | return ret; | |
1557 | } | |
1558 | ||
4cb3d99c JW |
1559 | /* Add a fake 'exit' subprog which could simplify subprog iteration |
1560 | * logic. 'subprog_cnt' should not be increased. | |
1561 | */ | |
1562 | subprog[env->subprog_cnt].start = insn_cnt; | |
1563 | ||
06ee7115 | 1564 | if (env->log.level & BPF_LOG_LEVEL2) |
cc8b0b92 | 1565 | for (i = 0; i < env->subprog_cnt; i++) |
9c8105bd | 1566 | verbose(env, "func#%d @%d\n", i, subprog[i].start); |
cc8b0b92 AS |
1567 | |
1568 | /* now check that all jumps are within the same subprog */ | |
4cb3d99c JW |
1569 | subprog_start = subprog[cur_subprog].start; |
1570 | subprog_end = subprog[cur_subprog + 1].start; | |
cc8b0b92 AS |
1571 | for (i = 0; i < insn_cnt; i++) { |
1572 | u8 code = insn[i].code; | |
1573 | ||
7f6e4312 MF |
1574 | if (code == (BPF_JMP | BPF_CALL) && |
1575 | insn[i].imm == BPF_FUNC_tail_call && | |
1576 | insn[i].src_reg != BPF_PSEUDO_CALL) | |
1577 | subprog[cur_subprog].has_tail_call = true; | |
09b28d76 AS |
1578 | if (BPF_CLASS(code) == BPF_LD && |
1579 | (BPF_MODE(code) == BPF_ABS || BPF_MODE(code) == BPF_IND)) | |
1580 | subprog[cur_subprog].has_ld_abs = true; | |
092ed096 | 1581 | if (BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32) |
cc8b0b92 AS |
1582 | goto next; |
1583 | if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL) | |
1584 | goto next; | |
1585 | off = i + insn[i].off + 1; | |
1586 | if (off < subprog_start || off >= subprog_end) { | |
1587 | verbose(env, "jump out of range from insn %d to %d\n", i, off); | |
1588 | return -EINVAL; | |
1589 | } | |
1590 | next: | |
1591 | if (i == subprog_end - 1) { | |
1592 | /* to avoid fall-through from one subprog into another | |
1593 | * the last insn of the subprog should be either exit | |
1594 | * or unconditional jump back | |
1595 | */ | |
1596 | if (code != (BPF_JMP | BPF_EXIT) && | |
1597 | code != (BPF_JMP | BPF_JA)) { | |
1598 | verbose(env, "last insn is not an exit or jmp\n"); | |
1599 | return -EINVAL; | |
1600 | } | |
1601 | subprog_start = subprog_end; | |
4cb3d99c JW |
1602 | cur_subprog++; |
1603 | if (cur_subprog < env->subprog_cnt) | |
9c8105bd | 1604 | subprog_end = subprog[cur_subprog + 1].start; |
cc8b0b92 AS |
1605 | } |
1606 | } | |
1607 | return 0; | |
1608 | } | |
1609 | ||
679c782d EC |
1610 | /* Parentage chain of this register (or stack slot) should take care of all |
1611 | * issues like callee-saved registers, stack slot allocation time, etc. | |
1612 | */ | |
f4d7e40a | 1613 | static int mark_reg_read(struct bpf_verifier_env *env, |
679c782d | 1614 | const struct bpf_reg_state *state, |
5327ed3d | 1615 | struct bpf_reg_state *parent, u8 flag) |
f4d7e40a AS |
1616 | { |
1617 | bool writes = parent == state->parent; /* Observe write marks */ | |
06ee7115 | 1618 | int cnt = 0; |
dc503a8a EC |
1619 | |
1620 | while (parent) { | |
1621 | /* if read wasn't screened by an earlier write ... */ | |
679c782d | 1622 | if (writes && state->live & REG_LIVE_WRITTEN) |
dc503a8a | 1623 | break; |
9242b5f5 AS |
1624 | if (parent->live & REG_LIVE_DONE) { |
1625 | verbose(env, "verifier BUG type %s var_off %lld off %d\n", | |
1626 | reg_type_str[parent->type], | |
1627 | parent->var_off.value, parent->off); | |
1628 | return -EFAULT; | |
1629 | } | |
5327ed3d JW |
1630 | /* The first condition is more likely to be true than the |
1631 | * second, checked it first. | |
1632 | */ | |
1633 | if ((parent->live & REG_LIVE_READ) == flag || | |
1634 | parent->live & REG_LIVE_READ64) | |
25af32da AS |
1635 | /* The parentage chain never changes and |
1636 | * this parent was already marked as LIVE_READ. | |
1637 | * There is no need to keep walking the chain again and | |
1638 | * keep re-marking all parents as LIVE_READ. | |
1639 | * This case happens when the same register is read | |
1640 | * multiple times without writes into it in-between. | |
5327ed3d JW |
1641 | * Also, if parent has the stronger REG_LIVE_READ64 set, |
1642 | * then no need to set the weak REG_LIVE_READ32. | |
25af32da AS |
1643 | */ |
1644 | break; | |
dc503a8a | 1645 | /* ... then we depend on parent's value */ |
5327ed3d JW |
1646 | parent->live |= flag; |
1647 | /* REG_LIVE_READ64 overrides REG_LIVE_READ32. */ | |
1648 | if (flag == REG_LIVE_READ64) | |
1649 | parent->live &= ~REG_LIVE_READ32; | |
dc503a8a EC |
1650 | state = parent; |
1651 | parent = state->parent; | |
f4d7e40a | 1652 | writes = true; |
06ee7115 | 1653 | cnt++; |
dc503a8a | 1654 | } |
06ee7115 AS |
1655 | |
1656 | if (env->longest_mark_read_walk < cnt) | |
1657 | env->longest_mark_read_walk = cnt; | |
f4d7e40a | 1658 | return 0; |
dc503a8a EC |
1659 | } |
1660 | ||
5327ed3d JW |
1661 | /* This function is supposed to be used by the following 32-bit optimization |
1662 | * code only. It returns TRUE if the source or destination register operates | |
1663 | * on 64-bit, otherwise return FALSE. | |
1664 | */ | |
1665 | static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn, | |
1666 | u32 regno, struct bpf_reg_state *reg, enum reg_arg_type t) | |
1667 | { | |
1668 | u8 code, class, op; | |
1669 | ||
1670 | code = insn->code; | |
1671 | class = BPF_CLASS(code); | |
1672 | op = BPF_OP(code); | |
1673 | if (class == BPF_JMP) { | |
1674 | /* BPF_EXIT for "main" will reach here. Return TRUE | |
1675 | * conservatively. | |
1676 | */ | |
1677 | if (op == BPF_EXIT) | |
1678 | return true; | |
1679 | if (op == BPF_CALL) { | |
1680 | /* BPF to BPF call will reach here because of marking | |
1681 | * caller saved clobber with DST_OP_NO_MARK for which we | |
1682 | * don't care the register def because they are anyway | |
1683 | * marked as NOT_INIT already. | |
1684 | */ | |
1685 | if (insn->src_reg == BPF_PSEUDO_CALL) | |
1686 | return false; | |
1687 | /* Helper call will reach here because of arg type | |
1688 | * check, conservatively return TRUE. | |
1689 | */ | |
1690 | if (t == SRC_OP) | |
1691 | return true; | |
1692 | ||
1693 | return false; | |
1694 | } | |
1695 | } | |
1696 | ||
1697 | if (class == BPF_ALU64 || class == BPF_JMP || | |
1698 | /* BPF_END always use BPF_ALU class. */ | |
1699 | (class == BPF_ALU && op == BPF_END && insn->imm == 64)) | |
1700 | return true; | |
1701 | ||
1702 | if (class == BPF_ALU || class == BPF_JMP32) | |
1703 | return false; | |
1704 | ||
1705 | if (class == BPF_LDX) { | |
1706 | if (t != SRC_OP) | |
1707 | return BPF_SIZE(code) == BPF_DW; | |
1708 | /* LDX source must be ptr. */ | |
1709 | return true; | |
1710 | } | |
1711 | ||
1712 | if (class == BPF_STX) { | |
83a28819 IL |
1713 | /* BPF_STX (including atomic variants) has multiple source |
1714 | * operands, one of which is a ptr. Check whether the caller is | |
1715 | * asking about it. | |
1716 | */ | |
1717 | if (t == SRC_OP && reg->type != SCALAR_VALUE) | |
5327ed3d JW |
1718 | return true; |
1719 | return BPF_SIZE(code) == BPF_DW; | |
1720 | } | |
1721 | ||
1722 | if (class == BPF_LD) { | |
1723 | u8 mode = BPF_MODE(code); | |
1724 | ||
1725 | /* LD_IMM64 */ | |
1726 | if (mode == BPF_IMM) | |
1727 | return true; | |
1728 | ||
1729 | /* Both LD_IND and LD_ABS return 32-bit data. */ | |
1730 | if (t != SRC_OP) | |
1731 | return false; | |
1732 | ||
1733 | /* Implicit ctx ptr. */ | |
1734 | if (regno == BPF_REG_6) | |
1735 | return true; | |
1736 | ||
1737 | /* Explicit source could be any width. */ | |
1738 | return true; | |
1739 | } | |
1740 | ||
1741 | if (class == BPF_ST) | |
1742 | /* The only source register for BPF_ST is a ptr. */ | |
1743 | return true; | |
1744 | ||
1745 | /* Conservatively return true at default. */ | |
1746 | return true; | |
1747 | } | |
1748 | ||
83a28819 IL |
1749 | /* Return the regno defined by the insn, or -1. */ |
1750 | static int insn_def_regno(const struct bpf_insn *insn) | |
b325fbca | 1751 | { |
83a28819 IL |
1752 | switch (BPF_CLASS(insn->code)) { |
1753 | case BPF_JMP: | |
1754 | case BPF_JMP32: | |
1755 | case BPF_ST: | |
1756 | return -1; | |
1757 | case BPF_STX: | |
1758 | if (BPF_MODE(insn->code) == BPF_ATOMIC && | |
1759 | (insn->imm & BPF_FETCH)) { | |
1760 | if (insn->imm == BPF_CMPXCHG) | |
1761 | return BPF_REG_0; | |
1762 | else | |
1763 | return insn->src_reg; | |
1764 | } else { | |
1765 | return -1; | |
1766 | } | |
1767 | default: | |
1768 | return insn->dst_reg; | |
1769 | } | |
b325fbca JW |
1770 | } |
1771 | ||
1772 | /* Return TRUE if INSN has defined any 32-bit value explicitly. */ | |
1773 | static bool insn_has_def32(struct bpf_verifier_env *env, struct bpf_insn *insn) | |
1774 | { | |
83a28819 IL |
1775 | int dst_reg = insn_def_regno(insn); |
1776 | ||
1777 | if (dst_reg == -1) | |
b325fbca JW |
1778 | return false; |
1779 | ||
83a28819 | 1780 | return !is_reg64(env, insn, dst_reg, NULL, DST_OP); |
b325fbca JW |
1781 | } |
1782 | ||
5327ed3d JW |
1783 | static void mark_insn_zext(struct bpf_verifier_env *env, |
1784 | struct bpf_reg_state *reg) | |
1785 | { | |
1786 | s32 def_idx = reg->subreg_def; | |
1787 | ||
1788 | if (def_idx == DEF_NOT_SUBREG) | |
1789 | return; | |
1790 | ||
1791 | env->insn_aux_data[def_idx - 1].zext_dst = true; | |
1792 | /* The dst will be zero extended, so won't be sub-register anymore. */ | |
1793 | reg->subreg_def = DEF_NOT_SUBREG; | |
1794 | } | |
1795 | ||
dc503a8a | 1796 | static int check_reg_arg(struct bpf_verifier_env *env, u32 regno, |
17a52670 AS |
1797 | enum reg_arg_type t) |
1798 | { | |
f4d7e40a AS |
1799 | struct bpf_verifier_state *vstate = env->cur_state; |
1800 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
5327ed3d | 1801 | struct bpf_insn *insn = env->prog->insnsi + env->insn_idx; |
c342dc10 | 1802 | struct bpf_reg_state *reg, *regs = state->regs; |
5327ed3d | 1803 | bool rw64; |
dc503a8a | 1804 | |
17a52670 | 1805 | if (regno >= MAX_BPF_REG) { |
61bd5218 | 1806 | verbose(env, "R%d is invalid\n", regno); |
17a52670 AS |
1807 | return -EINVAL; |
1808 | } | |
1809 | ||
c342dc10 | 1810 | reg = ®s[regno]; |
5327ed3d | 1811 | rw64 = is_reg64(env, insn, regno, reg, t); |
17a52670 AS |
1812 | if (t == SRC_OP) { |
1813 | /* check whether register used as source operand can be read */ | |
c342dc10 | 1814 | if (reg->type == NOT_INIT) { |
61bd5218 | 1815 | verbose(env, "R%d !read_ok\n", regno); |
17a52670 AS |
1816 | return -EACCES; |
1817 | } | |
679c782d | 1818 | /* We don't need to worry about FP liveness because it's read-only */ |
c342dc10 JW |
1819 | if (regno == BPF_REG_FP) |
1820 | return 0; | |
1821 | ||
5327ed3d JW |
1822 | if (rw64) |
1823 | mark_insn_zext(env, reg); | |
1824 | ||
1825 | return mark_reg_read(env, reg, reg->parent, | |
1826 | rw64 ? REG_LIVE_READ64 : REG_LIVE_READ32); | |
17a52670 AS |
1827 | } else { |
1828 | /* check whether register used as dest operand can be written to */ | |
1829 | if (regno == BPF_REG_FP) { | |
61bd5218 | 1830 | verbose(env, "frame pointer is read only\n"); |
17a52670 AS |
1831 | return -EACCES; |
1832 | } | |
c342dc10 | 1833 | reg->live |= REG_LIVE_WRITTEN; |
5327ed3d | 1834 | reg->subreg_def = rw64 ? DEF_NOT_SUBREG : env->insn_idx + 1; |
17a52670 | 1835 | if (t == DST_OP) |
61bd5218 | 1836 | mark_reg_unknown(env, regs, regno); |
17a52670 AS |
1837 | } |
1838 | return 0; | |
1839 | } | |
1840 | ||
b5dc0163 AS |
1841 | /* for any branch, call, exit record the history of jmps in the given state */ |
1842 | static int push_jmp_history(struct bpf_verifier_env *env, | |
1843 | struct bpf_verifier_state *cur) | |
1844 | { | |
1845 | u32 cnt = cur->jmp_history_cnt; | |
1846 | struct bpf_idx_pair *p; | |
1847 | ||
1848 | cnt++; | |
1849 | p = krealloc(cur->jmp_history, cnt * sizeof(*p), GFP_USER); | |
1850 | if (!p) | |
1851 | return -ENOMEM; | |
1852 | p[cnt - 1].idx = env->insn_idx; | |
1853 | p[cnt - 1].prev_idx = env->prev_insn_idx; | |
1854 | cur->jmp_history = p; | |
1855 | cur->jmp_history_cnt = cnt; | |
1856 | return 0; | |
1857 | } | |
1858 | ||
1859 | /* Backtrack one insn at a time. If idx is not at the top of recorded | |
1860 | * history then previous instruction came from straight line execution. | |
1861 | */ | |
1862 | static int get_prev_insn_idx(struct bpf_verifier_state *st, int i, | |
1863 | u32 *history) | |
1864 | { | |
1865 | u32 cnt = *history; | |
1866 | ||
1867 | if (cnt && st->jmp_history[cnt - 1].idx == i) { | |
1868 | i = st->jmp_history[cnt - 1].prev_idx; | |
1869 | (*history)--; | |
1870 | } else { | |
1871 | i--; | |
1872 | } | |
1873 | return i; | |
1874 | } | |
1875 | ||
1876 | /* For given verifier state backtrack_insn() is called from the last insn to | |
1877 | * the first insn. Its purpose is to compute a bitmask of registers and | |
1878 | * stack slots that needs precision in the parent verifier state. | |
1879 | */ | |
1880 | static int backtrack_insn(struct bpf_verifier_env *env, int idx, | |
1881 | u32 *reg_mask, u64 *stack_mask) | |
1882 | { | |
1883 | const struct bpf_insn_cbs cbs = { | |
1884 | .cb_print = verbose, | |
1885 | .private_data = env, | |
1886 | }; | |
1887 | struct bpf_insn *insn = env->prog->insnsi + idx; | |
1888 | u8 class = BPF_CLASS(insn->code); | |
1889 | u8 opcode = BPF_OP(insn->code); | |
1890 | u8 mode = BPF_MODE(insn->code); | |
1891 | u32 dreg = 1u << insn->dst_reg; | |
1892 | u32 sreg = 1u << insn->src_reg; | |
1893 | u32 spi; | |
1894 | ||
1895 | if (insn->code == 0) | |
1896 | return 0; | |
1897 | if (env->log.level & BPF_LOG_LEVEL) { | |
1898 | verbose(env, "regs=%x stack=%llx before ", *reg_mask, *stack_mask); | |
1899 | verbose(env, "%d: ", idx); | |
1900 | print_bpf_insn(&cbs, insn, env->allow_ptr_leaks); | |
1901 | } | |
1902 | ||
1903 | if (class == BPF_ALU || class == BPF_ALU64) { | |
1904 | if (!(*reg_mask & dreg)) | |
1905 | return 0; | |
1906 | if (opcode == BPF_MOV) { | |
1907 | if (BPF_SRC(insn->code) == BPF_X) { | |
1908 | /* dreg = sreg | |
1909 | * dreg needs precision after this insn | |
1910 | * sreg needs precision before this insn | |
1911 | */ | |
1912 | *reg_mask &= ~dreg; | |
1913 | *reg_mask |= sreg; | |
1914 | } else { | |
1915 | /* dreg = K | |
1916 | * dreg needs precision after this insn. | |
1917 | * Corresponding register is already marked | |
1918 | * as precise=true in this verifier state. | |
1919 | * No further markings in parent are necessary | |
1920 | */ | |
1921 | *reg_mask &= ~dreg; | |
1922 | } | |
1923 | } else { | |
1924 | if (BPF_SRC(insn->code) == BPF_X) { | |
1925 | /* dreg += sreg | |
1926 | * both dreg and sreg need precision | |
1927 | * before this insn | |
1928 | */ | |
1929 | *reg_mask |= sreg; | |
1930 | } /* else dreg += K | |
1931 | * dreg still needs precision before this insn | |
1932 | */ | |
1933 | } | |
1934 | } else if (class == BPF_LDX) { | |
1935 | if (!(*reg_mask & dreg)) | |
1936 | return 0; | |
1937 | *reg_mask &= ~dreg; | |
1938 | ||
1939 | /* scalars can only be spilled into stack w/o losing precision. | |
1940 | * Load from any other memory can be zero extended. | |
1941 | * The desire to keep that precision is already indicated | |
1942 | * by 'precise' mark in corresponding register of this state. | |
1943 | * No further tracking necessary. | |
1944 | */ | |
1945 | if (insn->src_reg != BPF_REG_FP) | |
1946 | return 0; | |
1947 | if (BPF_SIZE(insn->code) != BPF_DW) | |
1948 | return 0; | |
1949 | ||
1950 | /* dreg = *(u64 *)[fp - off] was a fill from the stack. | |
1951 | * that [fp - off] slot contains scalar that needs to be | |
1952 | * tracked with precision | |
1953 | */ | |
1954 | spi = (-insn->off - 1) / BPF_REG_SIZE; | |
1955 | if (spi >= 64) { | |
1956 | verbose(env, "BUG spi %d\n", spi); | |
1957 | WARN_ONCE(1, "verifier backtracking bug"); | |
1958 | return -EFAULT; | |
1959 | } | |
1960 | *stack_mask |= 1ull << spi; | |
b3b50f05 | 1961 | } else if (class == BPF_STX || class == BPF_ST) { |
b5dc0163 | 1962 | if (*reg_mask & dreg) |
b3b50f05 | 1963 | /* stx & st shouldn't be using _scalar_ dst_reg |
b5dc0163 AS |
1964 | * to access memory. It means backtracking |
1965 | * encountered a case of pointer subtraction. | |
1966 | */ | |
1967 | return -ENOTSUPP; | |
1968 | /* scalars can only be spilled into stack */ | |
1969 | if (insn->dst_reg != BPF_REG_FP) | |
1970 | return 0; | |
1971 | if (BPF_SIZE(insn->code) != BPF_DW) | |
1972 | return 0; | |
1973 | spi = (-insn->off - 1) / BPF_REG_SIZE; | |
1974 | if (spi >= 64) { | |
1975 | verbose(env, "BUG spi %d\n", spi); | |
1976 | WARN_ONCE(1, "verifier backtracking bug"); | |
1977 | return -EFAULT; | |
1978 | } | |
1979 | if (!(*stack_mask & (1ull << spi))) | |
1980 | return 0; | |
1981 | *stack_mask &= ~(1ull << spi); | |
b3b50f05 AN |
1982 | if (class == BPF_STX) |
1983 | *reg_mask |= sreg; | |
b5dc0163 AS |
1984 | } else if (class == BPF_JMP || class == BPF_JMP32) { |
1985 | if (opcode == BPF_CALL) { | |
1986 | if (insn->src_reg == BPF_PSEUDO_CALL) | |
1987 | return -ENOTSUPP; | |
1988 | /* regular helper call sets R0 */ | |
1989 | *reg_mask &= ~1; | |
1990 | if (*reg_mask & 0x3f) { | |
1991 | /* if backtracing was looking for registers R1-R5 | |
1992 | * they should have been found already. | |
1993 | */ | |
1994 | verbose(env, "BUG regs %x\n", *reg_mask); | |
1995 | WARN_ONCE(1, "verifier backtracking bug"); | |
1996 | return -EFAULT; | |
1997 | } | |
1998 | } else if (opcode == BPF_EXIT) { | |
1999 | return -ENOTSUPP; | |
2000 | } | |
2001 | } else if (class == BPF_LD) { | |
2002 | if (!(*reg_mask & dreg)) | |
2003 | return 0; | |
2004 | *reg_mask &= ~dreg; | |
2005 | /* It's ld_imm64 or ld_abs or ld_ind. | |
2006 | * For ld_imm64 no further tracking of precision | |
2007 | * into parent is necessary | |
2008 | */ | |
2009 | if (mode == BPF_IND || mode == BPF_ABS) | |
2010 | /* to be analyzed */ | |
2011 | return -ENOTSUPP; | |
b5dc0163 AS |
2012 | } |
2013 | return 0; | |
2014 | } | |
2015 | ||
2016 | /* the scalar precision tracking algorithm: | |
2017 | * . at the start all registers have precise=false. | |
2018 | * . scalar ranges are tracked as normal through alu and jmp insns. | |
2019 | * . once precise value of the scalar register is used in: | |
2020 | * . ptr + scalar alu | |
2021 | * . if (scalar cond K|scalar) | |
2022 | * . helper_call(.., scalar, ...) where ARG_CONST is expected | |
2023 | * backtrack through the verifier states and mark all registers and | |
2024 | * stack slots with spilled constants that these scalar regisers | |
2025 | * should be precise. | |
2026 | * . during state pruning two registers (or spilled stack slots) | |
2027 | * are equivalent if both are not precise. | |
2028 | * | |
2029 | * Note the verifier cannot simply walk register parentage chain, | |
2030 | * since many different registers and stack slots could have been | |
2031 | * used to compute single precise scalar. | |
2032 | * | |
2033 | * The approach of starting with precise=true for all registers and then | |
2034 | * backtrack to mark a register as not precise when the verifier detects | |
2035 | * that program doesn't care about specific value (e.g., when helper | |
2036 | * takes register as ARG_ANYTHING parameter) is not safe. | |
2037 | * | |
2038 | * It's ok to walk single parentage chain of the verifier states. | |
2039 | * It's possible that this backtracking will go all the way till 1st insn. | |
2040 | * All other branches will be explored for needing precision later. | |
2041 | * | |
2042 | * The backtracking needs to deal with cases like: | |
2043 | * R8=map_value(id=0,off=0,ks=4,vs=1952,imm=0) R9_w=map_value(id=0,off=40,ks=4,vs=1952,imm=0) | |
2044 | * r9 -= r8 | |
2045 | * r5 = r9 | |
2046 | * if r5 > 0x79f goto pc+7 | |
2047 | * R5_w=inv(id=0,umax_value=1951,var_off=(0x0; 0x7ff)) | |
2048 | * r5 += 1 | |
2049 | * ... | |
2050 | * call bpf_perf_event_output#25 | |
2051 | * where .arg5_type = ARG_CONST_SIZE_OR_ZERO | |
2052 | * | |
2053 | * and this case: | |
2054 | * r6 = 1 | |
2055 | * call foo // uses callee's r6 inside to compute r0 | |
2056 | * r0 += r6 | |
2057 | * if r0 == 0 goto | |
2058 | * | |
2059 | * to track above reg_mask/stack_mask needs to be independent for each frame. | |
2060 | * | |
2061 | * Also if parent's curframe > frame where backtracking started, | |
2062 | * the verifier need to mark registers in both frames, otherwise callees | |
2063 | * may incorrectly prune callers. This is similar to | |
2064 | * commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences") | |
2065 | * | |
2066 | * For now backtracking falls back into conservative marking. | |
2067 | */ | |
2068 | static void mark_all_scalars_precise(struct bpf_verifier_env *env, | |
2069 | struct bpf_verifier_state *st) | |
2070 | { | |
2071 | struct bpf_func_state *func; | |
2072 | struct bpf_reg_state *reg; | |
2073 | int i, j; | |
2074 | ||
2075 | /* big hammer: mark all scalars precise in this path. | |
2076 | * pop_stack may still get !precise scalars. | |
2077 | */ | |
2078 | for (; st; st = st->parent) | |
2079 | for (i = 0; i <= st->curframe; i++) { | |
2080 | func = st->frame[i]; | |
2081 | for (j = 0; j < BPF_REG_FP; j++) { | |
2082 | reg = &func->regs[j]; | |
2083 | if (reg->type != SCALAR_VALUE) | |
2084 | continue; | |
2085 | reg->precise = true; | |
2086 | } | |
2087 | for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) { | |
2088 | if (func->stack[j].slot_type[0] != STACK_SPILL) | |
2089 | continue; | |
2090 | reg = &func->stack[j].spilled_ptr; | |
2091 | if (reg->type != SCALAR_VALUE) | |
2092 | continue; | |
2093 | reg->precise = true; | |
2094 | } | |
2095 | } | |
2096 | } | |
2097 | ||
a3ce685d AS |
2098 | static int __mark_chain_precision(struct bpf_verifier_env *env, int regno, |
2099 | int spi) | |
b5dc0163 AS |
2100 | { |
2101 | struct bpf_verifier_state *st = env->cur_state; | |
2102 | int first_idx = st->first_insn_idx; | |
2103 | int last_idx = env->insn_idx; | |
2104 | struct bpf_func_state *func; | |
2105 | struct bpf_reg_state *reg; | |
a3ce685d AS |
2106 | u32 reg_mask = regno >= 0 ? 1u << regno : 0; |
2107 | u64 stack_mask = spi >= 0 ? 1ull << spi : 0; | |
b5dc0163 | 2108 | bool skip_first = true; |
a3ce685d | 2109 | bool new_marks = false; |
b5dc0163 AS |
2110 | int i, err; |
2111 | ||
2c78ee89 | 2112 | if (!env->bpf_capable) |
b5dc0163 AS |
2113 | return 0; |
2114 | ||
2115 | func = st->frame[st->curframe]; | |
a3ce685d AS |
2116 | if (regno >= 0) { |
2117 | reg = &func->regs[regno]; | |
2118 | if (reg->type != SCALAR_VALUE) { | |
2119 | WARN_ONCE(1, "backtracing misuse"); | |
2120 | return -EFAULT; | |
2121 | } | |
2122 | if (!reg->precise) | |
2123 | new_marks = true; | |
2124 | else | |
2125 | reg_mask = 0; | |
2126 | reg->precise = true; | |
b5dc0163 | 2127 | } |
b5dc0163 | 2128 | |
a3ce685d AS |
2129 | while (spi >= 0) { |
2130 | if (func->stack[spi].slot_type[0] != STACK_SPILL) { | |
2131 | stack_mask = 0; | |
2132 | break; | |
2133 | } | |
2134 | reg = &func->stack[spi].spilled_ptr; | |
2135 | if (reg->type != SCALAR_VALUE) { | |
2136 | stack_mask = 0; | |
2137 | break; | |
2138 | } | |
2139 | if (!reg->precise) | |
2140 | new_marks = true; | |
2141 | else | |
2142 | stack_mask = 0; | |
2143 | reg->precise = true; | |
2144 | break; | |
2145 | } | |
2146 | ||
2147 | if (!new_marks) | |
2148 | return 0; | |
2149 | if (!reg_mask && !stack_mask) | |
2150 | return 0; | |
b5dc0163 AS |
2151 | for (;;) { |
2152 | DECLARE_BITMAP(mask, 64); | |
b5dc0163 AS |
2153 | u32 history = st->jmp_history_cnt; |
2154 | ||
2155 | if (env->log.level & BPF_LOG_LEVEL) | |
2156 | verbose(env, "last_idx %d first_idx %d\n", last_idx, first_idx); | |
2157 | for (i = last_idx;;) { | |
2158 | if (skip_first) { | |
2159 | err = 0; | |
2160 | skip_first = false; | |
2161 | } else { | |
2162 | err = backtrack_insn(env, i, ®_mask, &stack_mask); | |
2163 | } | |
2164 | if (err == -ENOTSUPP) { | |
2165 | mark_all_scalars_precise(env, st); | |
2166 | return 0; | |
2167 | } else if (err) { | |
2168 | return err; | |
2169 | } | |
2170 | if (!reg_mask && !stack_mask) | |
2171 | /* Found assignment(s) into tracked register in this state. | |
2172 | * Since this state is already marked, just return. | |
2173 | * Nothing to be tracked further in the parent state. | |
2174 | */ | |
2175 | return 0; | |
2176 | if (i == first_idx) | |
2177 | break; | |
2178 | i = get_prev_insn_idx(st, i, &history); | |
2179 | if (i >= env->prog->len) { | |
2180 | /* This can happen if backtracking reached insn 0 | |
2181 | * and there are still reg_mask or stack_mask | |
2182 | * to backtrack. | |
2183 | * It means the backtracking missed the spot where | |
2184 | * particular register was initialized with a constant. | |
2185 | */ | |
2186 | verbose(env, "BUG backtracking idx %d\n", i); | |
2187 | WARN_ONCE(1, "verifier backtracking bug"); | |
2188 | return -EFAULT; | |
2189 | } | |
2190 | } | |
2191 | st = st->parent; | |
2192 | if (!st) | |
2193 | break; | |
2194 | ||
a3ce685d | 2195 | new_marks = false; |
b5dc0163 AS |
2196 | func = st->frame[st->curframe]; |
2197 | bitmap_from_u64(mask, reg_mask); | |
2198 | for_each_set_bit(i, mask, 32) { | |
2199 | reg = &func->regs[i]; | |
a3ce685d AS |
2200 | if (reg->type != SCALAR_VALUE) { |
2201 | reg_mask &= ~(1u << i); | |
b5dc0163 | 2202 | continue; |
a3ce685d | 2203 | } |
b5dc0163 AS |
2204 | if (!reg->precise) |
2205 | new_marks = true; | |
2206 | reg->precise = true; | |
2207 | } | |
2208 | ||
2209 | bitmap_from_u64(mask, stack_mask); | |
2210 | for_each_set_bit(i, mask, 64) { | |
2211 | if (i >= func->allocated_stack / BPF_REG_SIZE) { | |
2339cd6c AS |
2212 | /* the sequence of instructions: |
2213 | * 2: (bf) r3 = r10 | |
2214 | * 3: (7b) *(u64 *)(r3 -8) = r0 | |
2215 | * 4: (79) r4 = *(u64 *)(r10 -8) | |
2216 | * doesn't contain jmps. It's backtracked | |
2217 | * as a single block. | |
2218 | * During backtracking insn 3 is not recognized as | |
2219 | * stack access, so at the end of backtracking | |
2220 | * stack slot fp-8 is still marked in stack_mask. | |
2221 | * However the parent state may not have accessed | |
2222 | * fp-8 and it's "unallocated" stack space. | |
2223 | * In such case fallback to conservative. | |
b5dc0163 | 2224 | */ |
2339cd6c AS |
2225 | mark_all_scalars_precise(env, st); |
2226 | return 0; | |
b5dc0163 AS |
2227 | } |
2228 | ||
a3ce685d AS |
2229 | if (func->stack[i].slot_type[0] != STACK_SPILL) { |
2230 | stack_mask &= ~(1ull << i); | |
b5dc0163 | 2231 | continue; |
a3ce685d | 2232 | } |
b5dc0163 | 2233 | reg = &func->stack[i].spilled_ptr; |
a3ce685d AS |
2234 | if (reg->type != SCALAR_VALUE) { |
2235 | stack_mask &= ~(1ull << i); | |
b5dc0163 | 2236 | continue; |
a3ce685d | 2237 | } |
b5dc0163 AS |
2238 | if (!reg->precise) |
2239 | new_marks = true; | |
2240 | reg->precise = true; | |
2241 | } | |
2242 | if (env->log.level & BPF_LOG_LEVEL) { | |
2243 | print_verifier_state(env, func); | |
2244 | verbose(env, "parent %s regs=%x stack=%llx marks\n", | |
2245 | new_marks ? "didn't have" : "already had", | |
2246 | reg_mask, stack_mask); | |
2247 | } | |
2248 | ||
a3ce685d AS |
2249 | if (!reg_mask && !stack_mask) |
2250 | break; | |
b5dc0163 AS |
2251 | if (!new_marks) |
2252 | break; | |
2253 | ||
2254 | last_idx = st->last_insn_idx; | |
2255 | first_idx = st->first_insn_idx; | |
2256 | } | |
2257 | return 0; | |
2258 | } | |
2259 | ||
a3ce685d AS |
2260 | static int mark_chain_precision(struct bpf_verifier_env *env, int regno) |
2261 | { | |
2262 | return __mark_chain_precision(env, regno, -1); | |
2263 | } | |
2264 | ||
2265 | static int mark_chain_precision_stack(struct bpf_verifier_env *env, int spi) | |
2266 | { | |
2267 | return __mark_chain_precision(env, -1, spi); | |
2268 | } | |
b5dc0163 | 2269 | |
1be7f75d AS |
2270 | static bool is_spillable_regtype(enum bpf_reg_type type) |
2271 | { | |
2272 | switch (type) { | |
2273 | case PTR_TO_MAP_VALUE: | |
2274 | case PTR_TO_MAP_VALUE_OR_NULL: | |
2275 | case PTR_TO_STACK: | |
2276 | case PTR_TO_CTX: | |
969bf05e | 2277 | case PTR_TO_PACKET: |
de8f3a83 | 2278 | case PTR_TO_PACKET_META: |
969bf05e | 2279 | case PTR_TO_PACKET_END: |
d58e468b | 2280 | case PTR_TO_FLOW_KEYS: |
1be7f75d | 2281 | case CONST_PTR_TO_MAP: |
c64b7983 JS |
2282 | case PTR_TO_SOCKET: |
2283 | case PTR_TO_SOCKET_OR_NULL: | |
46f8bc92 MKL |
2284 | case PTR_TO_SOCK_COMMON: |
2285 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
655a51e5 MKL |
2286 | case PTR_TO_TCP_SOCK: |
2287 | case PTR_TO_TCP_SOCK_OR_NULL: | |
fada7fdc | 2288 | case PTR_TO_XDP_SOCK: |
65726b5b | 2289 | case PTR_TO_BTF_ID: |
b121b341 | 2290 | case PTR_TO_BTF_ID_OR_NULL: |
afbf21dc YS |
2291 | case PTR_TO_RDONLY_BUF: |
2292 | case PTR_TO_RDONLY_BUF_OR_NULL: | |
2293 | case PTR_TO_RDWR_BUF: | |
2294 | case PTR_TO_RDWR_BUF_OR_NULL: | |
eaa6bcb7 | 2295 | case PTR_TO_PERCPU_BTF_ID: |
744ea4e3 GR |
2296 | case PTR_TO_MEM: |
2297 | case PTR_TO_MEM_OR_NULL: | |
1be7f75d AS |
2298 | return true; |
2299 | default: | |
2300 | return false; | |
2301 | } | |
2302 | } | |
2303 | ||
cc2b14d5 AS |
2304 | /* Does this register contain a constant zero? */ |
2305 | static bool register_is_null(struct bpf_reg_state *reg) | |
2306 | { | |
2307 | return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0); | |
2308 | } | |
2309 | ||
f7cf25b2 AS |
2310 | static bool register_is_const(struct bpf_reg_state *reg) |
2311 | { | |
2312 | return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off); | |
2313 | } | |
2314 | ||
5689d49b YS |
2315 | static bool __is_scalar_unbounded(struct bpf_reg_state *reg) |
2316 | { | |
2317 | return tnum_is_unknown(reg->var_off) && | |
2318 | reg->smin_value == S64_MIN && reg->smax_value == S64_MAX && | |
2319 | reg->umin_value == 0 && reg->umax_value == U64_MAX && | |
2320 | reg->s32_min_value == S32_MIN && reg->s32_max_value == S32_MAX && | |
2321 | reg->u32_min_value == 0 && reg->u32_max_value == U32_MAX; | |
2322 | } | |
2323 | ||
2324 | static bool register_is_bounded(struct bpf_reg_state *reg) | |
2325 | { | |
2326 | return reg->type == SCALAR_VALUE && !__is_scalar_unbounded(reg); | |
2327 | } | |
2328 | ||
6e7e63cb JH |
2329 | static bool __is_pointer_value(bool allow_ptr_leaks, |
2330 | const struct bpf_reg_state *reg) | |
2331 | { | |
2332 | if (allow_ptr_leaks) | |
2333 | return false; | |
2334 | ||
2335 | return reg->type != SCALAR_VALUE; | |
2336 | } | |
2337 | ||
f7cf25b2 AS |
2338 | static void save_register_state(struct bpf_func_state *state, |
2339 | int spi, struct bpf_reg_state *reg) | |
2340 | { | |
2341 | int i; | |
2342 | ||
2343 | state->stack[spi].spilled_ptr = *reg; | |
2344 | state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN; | |
2345 | ||
2346 | for (i = 0; i < BPF_REG_SIZE; i++) | |
2347 | state->stack[spi].slot_type[i] = STACK_SPILL; | |
2348 | } | |
2349 | ||
01f810ac | 2350 | /* check_stack_{read,write}_fixed_off functions track spill/fill of registers, |
17a52670 AS |
2351 | * stack boundary and alignment are checked in check_mem_access() |
2352 | */ | |
01f810ac AM |
2353 | static int check_stack_write_fixed_off(struct bpf_verifier_env *env, |
2354 | /* stack frame we're writing to */ | |
2355 | struct bpf_func_state *state, | |
2356 | int off, int size, int value_regno, | |
2357 | int insn_idx) | |
17a52670 | 2358 | { |
f4d7e40a | 2359 | struct bpf_func_state *cur; /* state of the current function */ |
638f5b90 | 2360 | int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err; |
b5dc0163 | 2361 | u32 dst_reg = env->prog->insnsi[insn_idx].dst_reg; |
f7cf25b2 | 2362 | struct bpf_reg_state *reg = NULL; |
638f5b90 | 2363 | |
f4d7e40a | 2364 | err = realloc_func_state(state, round_up(slot + 1, BPF_REG_SIZE), |
fd978bf7 | 2365 | state->acquired_refs, true); |
638f5b90 AS |
2366 | if (err) |
2367 | return err; | |
9c399760 AS |
2368 | /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0, |
2369 | * so it's aligned access and [off, off + size) are within stack limits | |
2370 | */ | |
638f5b90 AS |
2371 | if (!env->allow_ptr_leaks && |
2372 | state->stack[spi].slot_type[0] == STACK_SPILL && | |
2373 | size != BPF_REG_SIZE) { | |
2374 | verbose(env, "attempt to corrupt spilled pointer on stack\n"); | |
2375 | return -EACCES; | |
2376 | } | |
17a52670 | 2377 | |
f4d7e40a | 2378 | cur = env->cur_state->frame[env->cur_state->curframe]; |
f7cf25b2 AS |
2379 | if (value_regno >= 0) |
2380 | reg = &cur->regs[value_regno]; | |
17a52670 | 2381 | |
5689d49b | 2382 | if (reg && size == BPF_REG_SIZE && register_is_bounded(reg) && |
2c78ee89 | 2383 | !register_is_null(reg) && env->bpf_capable) { |
b5dc0163 AS |
2384 | if (dst_reg != BPF_REG_FP) { |
2385 | /* The backtracking logic can only recognize explicit | |
2386 | * stack slot address like [fp - 8]. Other spill of | |
2387 | * scalar via different register has to be conervative. | |
2388 | * Backtrack from here and mark all registers as precise | |
2389 | * that contributed into 'reg' being a constant. | |
2390 | */ | |
2391 | err = mark_chain_precision(env, value_regno); | |
2392 | if (err) | |
2393 | return err; | |
2394 | } | |
f7cf25b2 AS |
2395 | save_register_state(state, spi, reg); |
2396 | } else if (reg && is_spillable_regtype(reg->type)) { | |
17a52670 | 2397 | /* register containing pointer is being spilled into stack */ |
9c399760 | 2398 | if (size != BPF_REG_SIZE) { |
f7cf25b2 | 2399 | verbose_linfo(env, insn_idx, "; "); |
61bd5218 | 2400 | verbose(env, "invalid size of register spill\n"); |
17a52670 AS |
2401 | return -EACCES; |
2402 | } | |
2403 | ||
f7cf25b2 | 2404 | if (state != cur && reg->type == PTR_TO_STACK) { |
f4d7e40a AS |
2405 | verbose(env, "cannot spill pointers to stack into stack frame of the caller\n"); |
2406 | return -EINVAL; | |
2407 | } | |
2408 | ||
2c78ee89 | 2409 | if (!env->bypass_spec_v4) { |
f7cf25b2 | 2410 | bool sanitize = false; |
17a52670 | 2411 | |
f7cf25b2 AS |
2412 | if (state->stack[spi].slot_type[0] == STACK_SPILL && |
2413 | register_is_const(&state->stack[spi].spilled_ptr)) | |
2414 | sanitize = true; | |
2415 | for (i = 0; i < BPF_REG_SIZE; i++) | |
2416 | if (state->stack[spi].slot_type[i] == STACK_MISC) { | |
2417 | sanitize = true; | |
2418 | break; | |
2419 | } | |
2420 | if (sanitize) { | |
af86ca4e AS |
2421 | int *poff = &env->insn_aux_data[insn_idx].sanitize_stack_off; |
2422 | int soff = (-spi - 1) * BPF_REG_SIZE; | |
2423 | ||
2424 | /* detected reuse of integer stack slot with a pointer | |
2425 | * which means either llvm is reusing stack slot or | |
2426 | * an attacker is trying to exploit CVE-2018-3639 | |
2427 | * (speculative store bypass) | |
2428 | * Have to sanitize that slot with preemptive | |
2429 | * store of zero. | |
2430 | */ | |
2431 | if (*poff && *poff != soff) { | |
2432 | /* disallow programs where single insn stores | |
2433 | * into two different stack slots, since verifier | |
2434 | * cannot sanitize them | |
2435 | */ | |
2436 | verbose(env, | |
2437 | "insn %d cannot access two stack slots fp%d and fp%d", | |
2438 | insn_idx, *poff, soff); | |
2439 | return -EINVAL; | |
2440 | } | |
2441 | *poff = soff; | |
2442 | } | |
af86ca4e | 2443 | } |
f7cf25b2 | 2444 | save_register_state(state, spi, reg); |
9c399760 | 2445 | } else { |
cc2b14d5 AS |
2446 | u8 type = STACK_MISC; |
2447 | ||
679c782d EC |
2448 | /* regular write of data into stack destroys any spilled ptr */ |
2449 | state->stack[spi].spilled_ptr.type = NOT_INIT; | |
0bae2d4d JW |
2450 | /* Mark slots as STACK_MISC if they belonged to spilled ptr. */ |
2451 | if (state->stack[spi].slot_type[0] == STACK_SPILL) | |
2452 | for (i = 0; i < BPF_REG_SIZE; i++) | |
2453 | state->stack[spi].slot_type[i] = STACK_MISC; | |
9c399760 | 2454 | |
cc2b14d5 AS |
2455 | /* only mark the slot as written if all 8 bytes were written |
2456 | * otherwise read propagation may incorrectly stop too soon | |
2457 | * when stack slots are partially written. | |
2458 | * This heuristic means that read propagation will be | |
2459 | * conservative, since it will add reg_live_read marks | |
2460 | * to stack slots all the way to first state when programs | |
2461 | * writes+reads less than 8 bytes | |
2462 | */ | |
2463 | if (size == BPF_REG_SIZE) | |
2464 | state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN; | |
2465 | ||
2466 | /* when we zero initialize stack slots mark them as such */ | |
b5dc0163 AS |
2467 | if (reg && register_is_null(reg)) { |
2468 | /* backtracking doesn't work for STACK_ZERO yet. */ | |
2469 | err = mark_chain_precision(env, value_regno); | |
2470 | if (err) | |
2471 | return err; | |
cc2b14d5 | 2472 | type = STACK_ZERO; |
b5dc0163 | 2473 | } |
cc2b14d5 | 2474 | |
0bae2d4d | 2475 | /* Mark slots affected by this stack write. */ |
9c399760 | 2476 | for (i = 0; i < size; i++) |
638f5b90 | 2477 | state->stack[spi].slot_type[(slot - i) % BPF_REG_SIZE] = |
cc2b14d5 | 2478 | type; |
17a52670 AS |
2479 | } |
2480 | return 0; | |
2481 | } | |
2482 | ||
01f810ac AM |
2483 | /* Write the stack: 'stack[ptr_regno + off] = value_regno'. 'ptr_regno' is |
2484 | * known to contain a variable offset. | |
2485 | * This function checks whether the write is permitted and conservatively | |
2486 | * tracks the effects of the write, considering that each stack slot in the | |
2487 | * dynamic range is potentially written to. | |
2488 | * | |
2489 | * 'off' includes 'regno->off'. | |
2490 | * 'value_regno' can be -1, meaning that an unknown value is being written to | |
2491 | * the stack. | |
2492 | * | |
2493 | * Spilled pointers in range are not marked as written because we don't know | |
2494 | * what's going to be actually written. This means that read propagation for | |
2495 | * future reads cannot be terminated by this write. | |
2496 | * | |
2497 | * For privileged programs, uninitialized stack slots are considered | |
2498 | * initialized by this write (even though we don't know exactly what offsets | |
2499 | * are going to be written to). The idea is that we don't want the verifier to | |
2500 | * reject future reads that access slots written to through variable offsets. | |
2501 | */ | |
2502 | static int check_stack_write_var_off(struct bpf_verifier_env *env, | |
2503 | /* func where register points to */ | |
2504 | struct bpf_func_state *state, | |
2505 | int ptr_regno, int off, int size, | |
2506 | int value_regno, int insn_idx) | |
2507 | { | |
2508 | struct bpf_func_state *cur; /* state of the current function */ | |
2509 | int min_off, max_off; | |
2510 | int i, err; | |
2511 | struct bpf_reg_state *ptr_reg = NULL, *value_reg = NULL; | |
2512 | bool writing_zero = false; | |
2513 | /* set if the fact that we're writing a zero is used to let any | |
2514 | * stack slots remain STACK_ZERO | |
2515 | */ | |
2516 | bool zero_used = false; | |
2517 | ||
2518 | cur = env->cur_state->frame[env->cur_state->curframe]; | |
2519 | ptr_reg = &cur->regs[ptr_regno]; | |
2520 | min_off = ptr_reg->smin_value + off; | |
2521 | max_off = ptr_reg->smax_value + off + size; | |
2522 | if (value_regno >= 0) | |
2523 | value_reg = &cur->regs[value_regno]; | |
2524 | if (value_reg && register_is_null(value_reg)) | |
2525 | writing_zero = true; | |
2526 | ||
2527 | err = realloc_func_state(state, round_up(-min_off, BPF_REG_SIZE), | |
2528 | state->acquired_refs, true); | |
2529 | if (err) | |
2530 | return err; | |
2531 | ||
2532 | ||
2533 | /* Variable offset writes destroy any spilled pointers in range. */ | |
2534 | for (i = min_off; i < max_off; i++) { | |
2535 | u8 new_type, *stype; | |
2536 | int slot, spi; | |
2537 | ||
2538 | slot = -i - 1; | |
2539 | spi = slot / BPF_REG_SIZE; | |
2540 | stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE]; | |
2541 | ||
2542 | if (!env->allow_ptr_leaks | |
2543 | && *stype != NOT_INIT | |
2544 | && *stype != SCALAR_VALUE) { | |
2545 | /* Reject the write if there's are spilled pointers in | |
2546 | * range. If we didn't reject here, the ptr status | |
2547 | * would be erased below (even though not all slots are | |
2548 | * actually overwritten), possibly opening the door to | |
2549 | * leaks. | |
2550 | */ | |
2551 | verbose(env, "spilled ptr in range of var-offset stack write; insn %d, ptr off: %d", | |
2552 | insn_idx, i); | |
2553 | return -EINVAL; | |
2554 | } | |
2555 | ||
2556 | /* Erase all spilled pointers. */ | |
2557 | state->stack[spi].spilled_ptr.type = NOT_INIT; | |
2558 | ||
2559 | /* Update the slot type. */ | |
2560 | new_type = STACK_MISC; | |
2561 | if (writing_zero && *stype == STACK_ZERO) { | |
2562 | new_type = STACK_ZERO; | |
2563 | zero_used = true; | |
2564 | } | |
2565 | /* If the slot is STACK_INVALID, we check whether it's OK to | |
2566 | * pretend that it will be initialized by this write. The slot | |
2567 | * might not actually be written to, and so if we mark it as | |
2568 | * initialized future reads might leak uninitialized memory. | |
2569 | * For privileged programs, we will accept such reads to slots | |
2570 | * that may or may not be written because, if we're reject | |
2571 | * them, the error would be too confusing. | |
2572 | */ | |
2573 | if (*stype == STACK_INVALID && !env->allow_uninit_stack) { | |
2574 | verbose(env, "uninit stack in range of var-offset write prohibited for !root; insn %d, off: %d", | |
2575 | insn_idx, i); | |
2576 | return -EINVAL; | |
2577 | } | |
2578 | *stype = new_type; | |
2579 | } | |
2580 | if (zero_used) { | |
2581 | /* backtracking doesn't work for STACK_ZERO yet. */ | |
2582 | err = mark_chain_precision(env, value_regno); | |
2583 | if (err) | |
2584 | return err; | |
2585 | } | |
2586 | return 0; | |
2587 | } | |
2588 | ||
2589 | /* When register 'dst_regno' is assigned some values from stack[min_off, | |
2590 | * max_off), we set the register's type according to the types of the | |
2591 | * respective stack slots. If all the stack values are known to be zeros, then | |
2592 | * so is the destination reg. Otherwise, the register is considered to be | |
2593 | * SCALAR. This function does not deal with register filling; the caller must | |
2594 | * ensure that all spilled registers in the stack range have been marked as | |
2595 | * read. | |
2596 | */ | |
2597 | static void mark_reg_stack_read(struct bpf_verifier_env *env, | |
2598 | /* func where src register points to */ | |
2599 | struct bpf_func_state *ptr_state, | |
2600 | int min_off, int max_off, int dst_regno) | |
2601 | { | |
2602 | struct bpf_verifier_state *vstate = env->cur_state; | |
2603 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
2604 | int i, slot, spi; | |
2605 | u8 *stype; | |
2606 | int zeros = 0; | |
2607 | ||
2608 | for (i = min_off; i < max_off; i++) { | |
2609 | slot = -i - 1; | |
2610 | spi = slot / BPF_REG_SIZE; | |
2611 | stype = ptr_state->stack[spi].slot_type; | |
2612 | if (stype[slot % BPF_REG_SIZE] != STACK_ZERO) | |
2613 | break; | |
2614 | zeros++; | |
2615 | } | |
2616 | if (zeros == max_off - min_off) { | |
2617 | /* any access_size read into register is zero extended, | |
2618 | * so the whole register == const_zero | |
2619 | */ | |
2620 | __mark_reg_const_zero(&state->regs[dst_regno]); | |
2621 | /* backtracking doesn't support STACK_ZERO yet, | |
2622 | * so mark it precise here, so that later | |
2623 | * backtracking can stop here. | |
2624 | * Backtracking may not need this if this register | |
2625 | * doesn't participate in pointer adjustment. | |
2626 | * Forward propagation of precise flag is not | |
2627 | * necessary either. This mark is only to stop | |
2628 | * backtracking. Any register that contributed | |
2629 | * to const 0 was marked precise before spill. | |
2630 | */ | |
2631 | state->regs[dst_regno].precise = true; | |
2632 | } else { | |
2633 | /* have read misc data from the stack */ | |
2634 | mark_reg_unknown(env, state->regs, dst_regno); | |
2635 | } | |
2636 | state->regs[dst_regno].live |= REG_LIVE_WRITTEN; | |
2637 | } | |
2638 | ||
2639 | /* Read the stack at 'off' and put the results into the register indicated by | |
2640 | * 'dst_regno'. It handles reg filling if the addressed stack slot is a | |
2641 | * spilled reg. | |
2642 | * | |
2643 | * 'dst_regno' can be -1, meaning that the read value is not going to a | |
2644 | * register. | |
2645 | * | |
2646 | * The access is assumed to be within the current stack bounds. | |
2647 | */ | |
2648 | static int check_stack_read_fixed_off(struct bpf_verifier_env *env, | |
2649 | /* func where src register points to */ | |
2650 | struct bpf_func_state *reg_state, | |
2651 | int off, int size, int dst_regno) | |
17a52670 | 2652 | { |
f4d7e40a AS |
2653 | struct bpf_verifier_state *vstate = env->cur_state; |
2654 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
638f5b90 | 2655 | int i, slot = -off - 1, spi = slot / BPF_REG_SIZE; |
f7cf25b2 | 2656 | struct bpf_reg_state *reg; |
638f5b90 | 2657 | u8 *stype; |
17a52670 | 2658 | |
f4d7e40a | 2659 | stype = reg_state->stack[spi].slot_type; |
f7cf25b2 | 2660 | reg = ®_state->stack[spi].spilled_ptr; |
17a52670 | 2661 | |
638f5b90 | 2662 | if (stype[0] == STACK_SPILL) { |
9c399760 | 2663 | if (size != BPF_REG_SIZE) { |
f7cf25b2 AS |
2664 | if (reg->type != SCALAR_VALUE) { |
2665 | verbose_linfo(env, env->insn_idx, "; "); | |
2666 | verbose(env, "invalid size of register fill\n"); | |
2667 | return -EACCES; | |
2668 | } | |
01f810ac AM |
2669 | if (dst_regno >= 0) { |
2670 | mark_reg_unknown(env, state->regs, dst_regno); | |
2671 | state->regs[dst_regno].live |= REG_LIVE_WRITTEN; | |
f7cf25b2 AS |
2672 | } |
2673 | mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64); | |
2674 | return 0; | |
17a52670 | 2675 | } |
9c399760 | 2676 | for (i = 1; i < BPF_REG_SIZE; i++) { |
638f5b90 | 2677 | if (stype[(slot - i) % BPF_REG_SIZE] != STACK_SPILL) { |
61bd5218 | 2678 | verbose(env, "corrupted spill memory\n"); |
17a52670 AS |
2679 | return -EACCES; |
2680 | } | |
2681 | } | |
2682 | ||
01f810ac | 2683 | if (dst_regno >= 0) { |
17a52670 | 2684 | /* restore register state from stack */ |
01f810ac | 2685 | state->regs[dst_regno] = *reg; |
2f18f62e AS |
2686 | /* mark reg as written since spilled pointer state likely |
2687 | * has its liveness marks cleared by is_state_visited() | |
2688 | * which resets stack/reg liveness for state transitions | |
2689 | */ | |
01f810ac | 2690 | state->regs[dst_regno].live |= REG_LIVE_WRITTEN; |
6e7e63cb | 2691 | } else if (__is_pointer_value(env->allow_ptr_leaks, reg)) { |
01f810ac | 2692 | /* If dst_regno==-1, the caller is asking us whether |
6e7e63cb JH |
2693 | * it is acceptable to use this value as a SCALAR_VALUE |
2694 | * (e.g. for XADD). | |
2695 | * We must not allow unprivileged callers to do that | |
2696 | * with spilled pointers. | |
2697 | */ | |
2698 | verbose(env, "leaking pointer from stack off %d\n", | |
2699 | off); | |
2700 | return -EACCES; | |
dc503a8a | 2701 | } |
f7cf25b2 | 2702 | mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64); |
17a52670 | 2703 | } else { |
01f810ac | 2704 | u8 type; |
cc2b14d5 | 2705 | |
17a52670 | 2706 | for (i = 0; i < size; i++) { |
01f810ac AM |
2707 | type = stype[(slot - i) % BPF_REG_SIZE]; |
2708 | if (type == STACK_MISC) | |
cc2b14d5 | 2709 | continue; |
01f810ac | 2710 | if (type == STACK_ZERO) |
cc2b14d5 | 2711 | continue; |
cc2b14d5 AS |
2712 | verbose(env, "invalid read from stack off %d+%d size %d\n", |
2713 | off, i, size); | |
2714 | return -EACCES; | |
2715 | } | |
f7cf25b2 | 2716 | mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64); |
01f810ac AM |
2717 | if (dst_regno >= 0) |
2718 | mark_reg_stack_read(env, reg_state, off, off + size, dst_regno); | |
17a52670 | 2719 | } |
f7cf25b2 | 2720 | return 0; |
17a52670 AS |
2721 | } |
2722 | ||
01f810ac AM |
2723 | enum stack_access_src { |
2724 | ACCESS_DIRECT = 1, /* the access is performed by an instruction */ | |
2725 | ACCESS_HELPER = 2, /* the access is performed by a helper */ | |
2726 | }; | |
2727 | ||
2728 | static int check_stack_range_initialized(struct bpf_verifier_env *env, | |
2729 | int regno, int off, int access_size, | |
2730 | bool zero_size_allowed, | |
2731 | enum stack_access_src type, | |
2732 | struct bpf_call_arg_meta *meta); | |
2733 | ||
2734 | static struct bpf_reg_state *reg_state(struct bpf_verifier_env *env, int regno) | |
2735 | { | |
2736 | return cur_regs(env) + regno; | |
2737 | } | |
2738 | ||
2739 | /* Read the stack at 'ptr_regno + off' and put the result into the register | |
2740 | * 'dst_regno'. | |
2741 | * 'off' includes the pointer register's fixed offset(i.e. 'ptr_regno.off'), | |
2742 | * but not its variable offset. | |
2743 | * 'size' is assumed to be <= reg size and the access is assumed to be aligned. | |
2744 | * | |
2745 | * As opposed to check_stack_read_fixed_off, this function doesn't deal with | |
2746 | * filling registers (i.e. reads of spilled register cannot be detected when | |
2747 | * the offset is not fixed). We conservatively mark 'dst_regno' as containing | |
2748 | * SCALAR_VALUE. That's why we assert that the 'ptr_regno' has a variable | |
2749 | * offset; for a fixed offset check_stack_read_fixed_off should be used | |
2750 | * instead. | |
2751 | */ | |
2752 | static int check_stack_read_var_off(struct bpf_verifier_env *env, | |
2753 | int ptr_regno, int off, int size, int dst_regno) | |
e4298d25 | 2754 | { |
01f810ac AM |
2755 | /* The state of the source register. */ |
2756 | struct bpf_reg_state *reg = reg_state(env, ptr_regno); | |
2757 | struct bpf_func_state *ptr_state = func(env, reg); | |
2758 | int err; | |
2759 | int min_off, max_off; | |
2760 | ||
2761 | /* Note that we pass a NULL meta, so raw access will not be permitted. | |
e4298d25 | 2762 | */ |
01f810ac AM |
2763 | err = check_stack_range_initialized(env, ptr_regno, off, size, |
2764 | false, ACCESS_DIRECT, NULL); | |
2765 | if (err) | |
2766 | return err; | |
2767 | ||
2768 | min_off = reg->smin_value + off; | |
2769 | max_off = reg->smax_value + off; | |
2770 | mark_reg_stack_read(env, ptr_state, min_off, max_off + size, dst_regno); | |
2771 | return 0; | |
2772 | } | |
2773 | ||
2774 | /* check_stack_read dispatches to check_stack_read_fixed_off or | |
2775 | * check_stack_read_var_off. | |
2776 | * | |
2777 | * The caller must ensure that the offset falls within the allocated stack | |
2778 | * bounds. | |
2779 | * | |
2780 | * 'dst_regno' is a register which will receive the value from the stack. It | |
2781 | * can be -1, meaning that the read value is not going to a register. | |
2782 | */ | |
2783 | static int check_stack_read(struct bpf_verifier_env *env, | |
2784 | int ptr_regno, int off, int size, | |
2785 | int dst_regno) | |
2786 | { | |
2787 | struct bpf_reg_state *reg = reg_state(env, ptr_regno); | |
2788 | struct bpf_func_state *state = func(env, reg); | |
2789 | int err; | |
2790 | /* Some accesses are only permitted with a static offset. */ | |
2791 | bool var_off = !tnum_is_const(reg->var_off); | |
2792 | ||
2793 | /* The offset is required to be static when reads don't go to a | |
2794 | * register, in order to not leak pointers (see | |
2795 | * check_stack_read_fixed_off). | |
2796 | */ | |
2797 | if (dst_regno < 0 && var_off) { | |
e4298d25 DB |
2798 | char tn_buf[48]; |
2799 | ||
2800 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
01f810ac | 2801 | verbose(env, "variable offset stack pointer cannot be passed into helper function; var_off=%s off=%d size=%d\n", |
e4298d25 DB |
2802 | tn_buf, off, size); |
2803 | return -EACCES; | |
2804 | } | |
01f810ac AM |
2805 | /* Variable offset is prohibited for unprivileged mode for simplicity |
2806 | * since it requires corresponding support in Spectre masking for stack | |
2807 | * ALU. See also retrieve_ptr_limit(). | |
2808 | */ | |
2809 | if (!env->bypass_spec_v1 && var_off) { | |
2810 | char tn_buf[48]; | |
e4298d25 | 2811 | |
01f810ac AM |
2812 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); |
2813 | verbose(env, "R%d variable offset stack access prohibited for !root, var_off=%s\n", | |
2814 | ptr_regno, tn_buf); | |
e4298d25 DB |
2815 | return -EACCES; |
2816 | } | |
2817 | ||
01f810ac AM |
2818 | if (!var_off) { |
2819 | off += reg->var_off.value; | |
2820 | err = check_stack_read_fixed_off(env, state, off, size, | |
2821 | dst_regno); | |
2822 | } else { | |
2823 | /* Variable offset stack reads need more conservative handling | |
2824 | * than fixed offset ones. Note that dst_regno >= 0 on this | |
2825 | * branch. | |
2826 | */ | |
2827 | err = check_stack_read_var_off(env, ptr_regno, off, size, | |
2828 | dst_regno); | |
2829 | } | |
2830 | return err; | |
2831 | } | |
2832 | ||
2833 | ||
2834 | /* check_stack_write dispatches to check_stack_write_fixed_off or | |
2835 | * check_stack_write_var_off. | |
2836 | * | |
2837 | * 'ptr_regno' is the register used as a pointer into the stack. | |
2838 | * 'off' includes 'ptr_regno->off', but not its variable offset (if any). | |
2839 | * 'value_regno' is the register whose value we're writing to the stack. It can | |
2840 | * be -1, meaning that we're not writing from a register. | |
2841 | * | |
2842 | * The caller must ensure that the offset falls within the maximum stack size. | |
2843 | */ | |
2844 | static int check_stack_write(struct bpf_verifier_env *env, | |
2845 | int ptr_regno, int off, int size, | |
2846 | int value_regno, int insn_idx) | |
2847 | { | |
2848 | struct bpf_reg_state *reg = reg_state(env, ptr_regno); | |
2849 | struct bpf_func_state *state = func(env, reg); | |
2850 | int err; | |
2851 | ||
2852 | if (tnum_is_const(reg->var_off)) { | |
2853 | off += reg->var_off.value; | |
2854 | err = check_stack_write_fixed_off(env, state, off, size, | |
2855 | value_regno, insn_idx); | |
2856 | } else { | |
2857 | /* Variable offset stack reads need more conservative handling | |
2858 | * than fixed offset ones. | |
2859 | */ | |
2860 | err = check_stack_write_var_off(env, state, | |
2861 | ptr_regno, off, size, | |
2862 | value_regno, insn_idx); | |
2863 | } | |
2864 | return err; | |
e4298d25 DB |
2865 | } |
2866 | ||
591fe988 DB |
2867 | static int check_map_access_type(struct bpf_verifier_env *env, u32 regno, |
2868 | int off, int size, enum bpf_access_type type) | |
2869 | { | |
2870 | struct bpf_reg_state *regs = cur_regs(env); | |
2871 | struct bpf_map *map = regs[regno].map_ptr; | |
2872 | u32 cap = bpf_map_flags_to_cap(map); | |
2873 | ||
2874 | if (type == BPF_WRITE && !(cap & BPF_MAP_CAN_WRITE)) { | |
2875 | verbose(env, "write into map forbidden, value_size=%d off=%d size=%d\n", | |
2876 | map->value_size, off, size); | |
2877 | return -EACCES; | |
2878 | } | |
2879 | ||
2880 | if (type == BPF_READ && !(cap & BPF_MAP_CAN_READ)) { | |
2881 | verbose(env, "read from map forbidden, value_size=%d off=%d size=%d\n", | |
2882 | map->value_size, off, size); | |
2883 | return -EACCES; | |
2884 | } | |
2885 | ||
2886 | return 0; | |
2887 | } | |
2888 | ||
457f4436 AN |
2889 | /* check read/write into memory region (e.g., map value, ringbuf sample, etc) */ |
2890 | static int __check_mem_access(struct bpf_verifier_env *env, int regno, | |
2891 | int off, int size, u32 mem_size, | |
2892 | bool zero_size_allowed) | |
17a52670 | 2893 | { |
457f4436 AN |
2894 | bool size_ok = size > 0 || (size == 0 && zero_size_allowed); |
2895 | struct bpf_reg_state *reg; | |
2896 | ||
2897 | if (off >= 0 && size_ok && (u64)off + size <= mem_size) | |
2898 | return 0; | |
17a52670 | 2899 | |
457f4436 AN |
2900 | reg = &cur_regs(env)[regno]; |
2901 | switch (reg->type) { | |
2902 | case PTR_TO_MAP_VALUE: | |
61bd5218 | 2903 | verbose(env, "invalid access to map value, value_size=%d off=%d size=%d\n", |
457f4436 AN |
2904 | mem_size, off, size); |
2905 | break; | |
2906 | case PTR_TO_PACKET: | |
2907 | case PTR_TO_PACKET_META: | |
2908 | case PTR_TO_PACKET_END: | |
2909 | verbose(env, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n", | |
2910 | off, size, regno, reg->id, off, mem_size); | |
2911 | break; | |
2912 | case PTR_TO_MEM: | |
2913 | default: | |
2914 | verbose(env, "invalid access to memory, mem_size=%u off=%d size=%d\n", | |
2915 | mem_size, off, size); | |
17a52670 | 2916 | } |
457f4436 AN |
2917 | |
2918 | return -EACCES; | |
17a52670 AS |
2919 | } |
2920 | ||
457f4436 AN |
2921 | /* check read/write into a memory region with possible variable offset */ |
2922 | static int check_mem_region_access(struct bpf_verifier_env *env, u32 regno, | |
2923 | int off, int size, u32 mem_size, | |
2924 | bool zero_size_allowed) | |
dbcfe5f7 | 2925 | { |
f4d7e40a AS |
2926 | struct bpf_verifier_state *vstate = env->cur_state; |
2927 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
dbcfe5f7 GB |
2928 | struct bpf_reg_state *reg = &state->regs[regno]; |
2929 | int err; | |
2930 | ||
457f4436 | 2931 | /* We may have adjusted the register pointing to memory region, so we |
f1174f77 EC |
2932 | * need to try adding each of min_value and max_value to off |
2933 | * to make sure our theoretical access will be safe. | |
dbcfe5f7 | 2934 | */ |
06ee7115 | 2935 | if (env->log.level & BPF_LOG_LEVEL) |
61bd5218 | 2936 | print_verifier_state(env, state); |
b7137c4e | 2937 | |
dbcfe5f7 GB |
2938 | /* The minimum value is only important with signed |
2939 | * comparisons where we can't assume the floor of a | |
2940 | * value is 0. If we are using signed variables for our | |
2941 | * index'es we need to make sure that whatever we use | |
2942 | * will have a set floor within our range. | |
2943 | */ | |
b7137c4e DB |
2944 | if (reg->smin_value < 0 && |
2945 | (reg->smin_value == S64_MIN || | |
2946 | (off + reg->smin_value != (s64)(s32)(off + reg->smin_value)) || | |
2947 | reg->smin_value + off < 0)) { | |
61bd5218 | 2948 | verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", |
dbcfe5f7 GB |
2949 | regno); |
2950 | return -EACCES; | |
2951 | } | |
457f4436 AN |
2952 | err = __check_mem_access(env, regno, reg->smin_value + off, size, |
2953 | mem_size, zero_size_allowed); | |
dbcfe5f7 | 2954 | if (err) { |
457f4436 | 2955 | verbose(env, "R%d min value is outside of the allowed memory range\n", |
61bd5218 | 2956 | regno); |
dbcfe5f7 GB |
2957 | return err; |
2958 | } | |
2959 | ||
b03c9f9f EC |
2960 | /* If we haven't set a max value then we need to bail since we can't be |
2961 | * sure we won't do bad things. | |
2962 | * If reg->umax_value + off could overflow, treat that as unbounded too. | |
dbcfe5f7 | 2963 | */ |
b03c9f9f | 2964 | if (reg->umax_value >= BPF_MAX_VAR_OFF) { |
457f4436 | 2965 | verbose(env, "R%d unbounded memory access, make sure to bounds check any such access\n", |
dbcfe5f7 GB |
2966 | regno); |
2967 | return -EACCES; | |
2968 | } | |
457f4436 AN |
2969 | err = __check_mem_access(env, regno, reg->umax_value + off, size, |
2970 | mem_size, zero_size_allowed); | |
2971 | if (err) { | |
2972 | verbose(env, "R%d max value is outside of the allowed memory range\n", | |
61bd5218 | 2973 | regno); |
457f4436 AN |
2974 | return err; |
2975 | } | |
2976 | ||
2977 | return 0; | |
2978 | } | |
d83525ca | 2979 | |
457f4436 AN |
2980 | /* check read/write into a map element with possible variable offset */ |
2981 | static int check_map_access(struct bpf_verifier_env *env, u32 regno, | |
2982 | int off, int size, bool zero_size_allowed) | |
2983 | { | |
2984 | struct bpf_verifier_state *vstate = env->cur_state; | |
2985 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
2986 | struct bpf_reg_state *reg = &state->regs[regno]; | |
2987 | struct bpf_map *map = reg->map_ptr; | |
2988 | int err; | |
2989 | ||
2990 | err = check_mem_region_access(env, regno, off, size, map->value_size, | |
2991 | zero_size_allowed); | |
2992 | if (err) | |
2993 | return err; | |
2994 | ||
2995 | if (map_value_has_spin_lock(map)) { | |
2996 | u32 lock = map->spin_lock_off; | |
d83525ca AS |
2997 | |
2998 | /* if any part of struct bpf_spin_lock can be touched by | |
2999 | * load/store reject this program. | |
3000 | * To check that [x1, x2) overlaps with [y1, y2) | |
3001 | * it is sufficient to check x1 < y2 && y1 < x2. | |
3002 | */ | |
3003 | if (reg->smin_value + off < lock + sizeof(struct bpf_spin_lock) && | |
3004 | lock < reg->umax_value + off + size) { | |
3005 | verbose(env, "bpf_spin_lock cannot be accessed directly by load/store\n"); | |
3006 | return -EACCES; | |
3007 | } | |
3008 | } | |
f1174f77 | 3009 | return err; |
dbcfe5f7 GB |
3010 | } |
3011 | ||
969bf05e AS |
3012 | #define MAX_PACKET_OFF 0xffff |
3013 | ||
7e40781c UP |
3014 | static enum bpf_prog_type resolve_prog_type(struct bpf_prog *prog) |
3015 | { | |
3aac1ead | 3016 | return prog->aux->dst_prog ? prog->aux->dst_prog->type : prog->type; |
7e40781c UP |
3017 | } |
3018 | ||
58e2af8b | 3019 | static bool may_access_direct_pkt_data(struct bpf_verifier_env *env, |
3a0af8fd TG |
3020 | const struct bpf_call_arg_meta *meta, |
3021 | enum bpf_access_type t) | |
4acf6c0b | 3022 | { |
7e40781c UP |
3023 | enum bpf_prog_type prog_type = resolve_prog_type(env->prog); |
3024 | ||
3025 | switch (prog_type) { | |
5d66fa7d | 3026 | /* Program types only with direct read access go here! */ |
3a0af8fd TG |
3027 | case BPF_PROG_TYPE_LWT_IN: |
3028 | case BPF_PROG_TYPE_LWT_OUT: | |
004d4b27 | 3029 | case BPF_PROG_TYPE_LWT_SEG6LOCAL: |
2dbb9b9e | 3030 | case BPF_PROG_TYPE_SK_REUSEPORT: |
5d66fa7d | 3031 | case BPF_PROG_TYPE_FLOW_DISSECTOR: |
d5563d36 | 3032 | case BPF_PROG_TYPE_CGROUP_SKB: |
3a0af8fd TG |
3033 | if (t == BPF_WRITE) |
3034 | return false; | |
8731745e | 3035 | fallthrough; |
5d66fa7d DB |
3036 | |
3037 | /* Program types with direct read + write access go here! */ | |
36bbef52 DB |
3038 | case BPF_PROG_TYPE_SCHED_CLS: |
3039 | case BPF_PROG_TYPE_SCHED_ACT: | |
4acf6c0b | 3040 | case BPF_PROG_TYPE_XDP: |
3a0af8fd | 3041 | case BPF_PROG_TYPE_LWT_XMIT: |
8a31db56 | 3042 | case BPF_PROG_TYPE_SK_SKB: |
4f738adb | 3043 | case BPF_PROG_TYPE_SK_MSG: |
36bbef52 DB |
3044 | if (meta) |
3045 | return meta->pkt_access; | |
3046 | ||
3047 | env->seen_direct_write = true; | |
4acf6c0b | 3048 | return true; |
0d01da6a SF |
3049 | |
3050 | case BPF_PROG_TYPE_CGROUP_SOCKOPT: | |
3051 | if (t == BPF_WRITE) | |
3052 | env->seen_direct_write = true; | |
3053 | ||
3054 | return true; | |
3055 | ||
4acf6c0b BB |
3056 | default: |
3057 | return false; | |
3058 | } | |
3059 | } | |
3060 | ||
f1174f77 | 3061 | static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, |
9fd29c08 | 3062 | int size, bool zero_size_allowed) |
f1174f77 | 3063 | { |
638f5b90 | 3064 | struct bpf_reg_state *regs = cur_regs(env); |
f1174f77 EC |
3065 | struct bpf_reg_state *reg = ®s[regno]; |
3066 | int err; | |
3067 | ||
3068 | /* We may have added a variable offset to the packet pointer; but any | |
3069 | * reg->range we have comes after that. We are only checking the fixed | |
3070 | * offset. | |
3071 | */ | |
3072 | ||
3073 | /* We don't allow negative numbers, because we aren't tracking enough | |
3074 | * detail to prove they're safe. | |
3075 | */ | |
b03c9f9f | 3076 | if (reg->smin_value < 0) { |
61bd5218 | 3077 | verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", |
f1174f77 EC |
3078 | regno); |
3079 | return -EACCES; | |
3080 | } | |
6d94e741 AS |
3081 | |
3082 | err = reg->range < 0 ? -EINVAL : | |
3083 | __check_mem_access(env, regno, off, size, reg->range, | |
457f4436 | 3084 | zero_size_allowed); |
f1174f77 | 3085 | if (err) { |
61bd5218 | 3086 | verbose(env, "R%d offset is outside of the packet\n", regno); |
f1174f77 EC |
3087 | return err; |
3088 | } | |
e647815a | 3089 | |
457f4436 | 3090 | /* __check_mem_access has made sure "off + size - 1" is within u16. |
e647815a JW |
3091 | * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff, |
3092 | * otherwise find_good_pkt_pointers would have refused to set range info | |
457f4436 | 3093 | * that __check_mem_access would have rejected this pkt access. |
e647815a JW |
3094 | * Therefore, "off + reg->umax_value + size - 1" won't overflow u32. |
3095 | */ | |
3096 | env->prog->aux->max_pkt_offset = | |
3097 | max_t(u32, env->prog->aux->max_pkt_offset, | |
3098 | off + reg->umax_value + size - 1); | |
3099 | ||
f1174f77 EC |
3100 | return err; |
3101 | } | |
3102 | ||
3103 | /* check access to 'struct bpf_context' fields. Supports fixed offsets only */ | |
31fd8581 | 3104 | static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size, |
9e15db66 | 3105 | enum bpf_access_type t, enum bpf_reg_type *reg_type, |
22dc4a0f | 3106 | struct btf **btf, u32 *btf_id) |
17a52670 | 3107 | { |
f96da094 DB |
3108 | struct bpf_insn_access_aux info = { |
3109 | .reg_type = *reg_type, | |
9e15db66 | 3110 | .log = &env->log, |
f96da094 | 3111 | }; |
31fd8581 | 3112 | |
4f9218aa | 3113 | if (env->ops->is_valid_access && |
5e43f899 | 3114 | env->ops->is_valid_access(off, size, t, env->prog, &info)) { |
f96da094 DB |
3115 | /* A non zero info.ctx_field_size indicates that this field is a |
3116 | * candidate for later verifier transformation to load the whole | |
3117 | * field and then apply a mask when accessed with a narrower | |
3118 | * access than actual ctx access size. A zero info.ctx_field_size | |
3119 | * will only allow for whole field access and rejects any other | |
3120 | * type of narrower access. | |
31fd8581 | 3121 | */ |
23994631 | 3122 | *reg_type = info.reg_type; |
31fd8581 | 3123 | |
22dc4a0f AN |
3124 | if (*reg_type == PTR_TO_BTF_ID || *reg_type == PTR_TO_BTF_ID_OR_NULL) { |
3125 | *btf = info.btf; | |
9e15db66 | 3126 | *btf_id = info.btf_id; |
22dc4a0f | 3127 | } else { |
9e15db66 | 3128 | env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size; |
22dc4a0f | 3129 | } |
32bbe007 AS |
3130 | /* remember the offset of last byte accessed in ctx */ |
3131 | if (env->prog->aux->max_ctx_offset < off + size) | |
3132 | env->prog->aux->max_ctx_offset = off + size; | |
17a52670 | 3133 | return 0; |
32bbe007 | 3134 | } |
17a52670 | 3135 | |
61bd5218 | 3136 | verbose(env, "invalid bpf_context access off=%d size=%d\n", off, size); |
17a52670 AS |
3137 | return -EACCES; |
3138 | } | |
3139 | ||
d58e468b PP |
3140 | static int check_flow_keys_access(struct bpf_verifier_env *env, int off, |
3141 | int size) | |
3142 | { | |
3143 | if (size < 0 || off < 0 || | |
3144 | (u64)off + size > sizeof(struct bpf_flow_keys)) { | |
3145 | verbose(env, "invalid access to flow keys off=%d size=%d\n", | |
3146 | off, size); | |
3147 | return -EACCES; | |
3148 | } | |
3149 | return 0; | |
3150 | } | |
3151 | ||
5f456649 MKL |
3152 | static int check_sock_access(struct bpf_verifier_env *env, int insn_idx, |
3153 | u32 regno, int off, int size, | |
3154 | enum bpf_access_type t) | |
c64b7983 JS |
3155 | { |
3156 | struct bpf_reg_state *regs = cur_regs(env); | |
3157 | struct bpf_reg_state *reg = ®s[regno]; | |
5f456649 | 3158 | struct bpf_insn_access_aux info = {}; |
46f8bc92 | 3159 | bool valid; |
c64b7983 JS |
3160 | |
3161 | if (reg->smin_value < 0) { | |
3162 | verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", | |
3163 | regno); | |
3164 | return -EACCES; | |
3165 | } | |
3166 | ||
46f8bc92 MKL |
3167 | switch (reg->type) { |
3168 | case PTR_TO_SOCK_COMMON: | |
3169 | valid = bpf_sock_common_is_valid_access(off, size, t, &info); | |
3170 | break; | |
3171 | case PTR_TO_SOCKET: | |
3172 | valid = bpf_sock_is_valid_access(off, size, t, &info); | |
3173 | break; | |
655a51e5 MKL |
3174 | case PTR_TO_TCP_SOCK: |
3175 | valid = bpf_tcp_sock_is_valid_access(off, size, t, &info); | |
3176 | break; | |
fada7fdc JL |
3177 | case PTR_TO_XDP_SOCK: |
3178 | valid = bpf_xdp_sock_is_valid_access(off, size, t, &info); | |
3179 | break; | |
46f8bc92 MKL |
3180 | default: |
3181 | valid = false; | |
c64b7983 JS |
3182 | } |
3183 | ||
5f456649 | 3184 | |
46f8bc92 MKL |
3185 | if (valid) { |
3186 | env->insn_aux_data[insn_idx].ctx_field_size = | |
3187 | info.ctx_field_size; | |
3188 | return 0; | |
3189 | } | |
3190 | ||
3191 | verbose(env, "R%d invalid %s access off=%d size=%d\n", | |
3192 | regno, reg_type_str[reg->type], off, size); | |
3193 | ||
3194 | return -EACCES; | |
c64b7983 JS |
3195 | } |
3196 | ||
4cabc5b1 DB |
3197 | static bool is_pointer_value(struct bpf_verifier_env *env, int regno) |
3198 | { | |
2a159c6f | 3199 | return __is_pointer_value(env->allow_ptr_leaks, reg_state(env, regno)); |
4cabc5b1 DB |
3200 | } |
3201 | ||
f37a8cb8 DB |
3202 | static bool is_ctx_reg(struct bpf_verifier_env *env, int regno) |
3203 | { | |
2a159c6f | 3204 | const struct bpf_reg_state *reg = reg_state(env, regno); |
f37a8cb8 | 3205 | |
46f8bc92 MKL |
3206 | return reg->type == PTR_TO_CTX; |
3207 | } | |
3208 | ||
3209 | static bool is_sk_reg(struct bpf_verifier_env *env, int regno) | |
3210 | { | |
3211 | const struct bpf_reg_state *reg = reg_state(env, regno); | |
3212 | ||
3213 | return type_is_sk_pointer(reg->type); | |
f37a8cb8 DB |
3214 | } |
3215 | ||
ca369602 DB |
3216 | static bool is_pkt_reg(struct bpf_verifier_env *env, int regno) |
3217 | { | |
2a159c6f | 3218 | const struct bpf_reg_state *reg = reg_state(env, regno); |
ca369602 DB |
3219 | |
3220 | return type_is_pkt_pointer(reg->type); | |
3221 | } | |
3222 | ||
4b5defde DB |
3223 | static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno) |
3224 | { | |
3225 | const struct bpf_reg_state *reg = reg_state(env, regno); | |
3226 | ||
3227 | /* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */ | |
3228 | return reg->type == PTR_TO_FLOW_KEYS; | |
3229 | } | |
3230 | ||
61bd5218 JK |
3231 | static int check_pkt_ptr_alignment(struct bpf_verifier_env *env, |
3232 | const struct bpf_reg_state *reg, | |
d1174416 | 3233 | int off, int size, bool strict) |
969bf05e | 3234 | { |
f1174f77 | 3235 | struct tnum reg_off; |
e07b98d9 | 3236 | int ip_align; |
d1174416 DM |
3237 | |
3238 | /* Byte size accesses are always allowed. */ | |
3239 | if (!strict || size == 1) | |
3240 | return 0; | |
3241 | ||
e4eda884 DM |
3242 | /* For platforms that do not have a Kconfig enabling |
3243 | * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of | |
3244 | * NET_IP_ALIGN is universally set to '2'. And on platforms | |
3245 | * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get | |
3246 | * to this code only in strict mode where we want to emulate | |
3247 | * the NET_IP_ALIGN==2 checking. Therefore use an | |
3248 | * unconditional IP align value of '2'. | |
e07b98d9 | 3249 | */ |
e4eda884 | 3250 | ip_align = 2; |
f1174f77 EC |
3251 | |
3252 | reg_off = tnum_add(reg->var_off, tnum_const(ip_align + reg->off + off)); | |
3253 | if (!tnum_is_aligned(reg_off, size)) { | |
3254 | char tn_buf[48]; | |
3255 | ||
3256 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
61bd5218 JK |
3257 | verbose(env, |
3258 | "misaligned packet access off %d+%s+%d+%d size %d\n", | |
f1174f77 | 3259 | ip_align, tn_buf, reg->off, off, size); |
969bf05e AS |
3260 | return -EACCES; |
3261 | } | |
79adffcd | 3262 | |
969bf05e AS |
3263 | return 0; |
3264 | } | |
3265 | ||
61bd5218 JK |
3266 | static int check_generic_ptr_alignment(struct bpf_verifier_env *env, |
3267 | const struct bpf_reg_state *reg, | |
f1174f77 EC |
3268 | const char *pointer_desc, |
3269 | int off, int size, bool strict) | |
79adffcd | 3270 | { |
f1174f77 EC |
3271 | struct tnum reg_off; |
3272 | ||
3273 | /* Byte size accesses are always allowed. */ | |
3274 | if (!strict || size == 1) | |
3275 | return 0; | |
3276 | ||
3277 | reg_off = tnum_add(reg->var_off, tnum_const(reg->off + off)); | |
3278 | if (!tnum_is_aligned(reg_off, size)) { | |
3279 | char tn_buf[48]; | |
3280 | ||
3281 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
61bd5218 | 3282 | verbose(env, "misaligned %saccess off %s+%d+%d size %d\n", |
f1174f77 | 3283 | pointer_desc, tn_buf, reg->off, off, size); |
79adffcd DB |
3284 | return -EACCES; |
3285 | } | |
3286 | ||
969bf05e AS |
3287 | return 0; |
3288 | } | |
3289 | ||
e07b98d9 | 3290 | static int check_ptr_alignment(struct bpf_verifier_env *env, |
ca369602 DB |
3291 | const struct bpf_reg_state *reg, int off, |
3292 | int size, bool strict_alignment_once) | |
79adffcd | 3293 | { |
ca369602 | 3294 | bool strict = env->strict_alignment || strict_alignment_once; |
f1174f77 | 3295 | const char *pointer_desc = ""; |
d1174416 | 3296 | |
79adffcd DB |
3297 | switch (reg->type) { |
3298 | case PTR_TO_PACKET: | |
de8f3a83 DB |
3299 | case PTR_TO_PACKET_META: |
3300 | /* Special case, because of NET_IP_ALIGN. Given metadata sits | |
3301 | * right in front, treat it the very same way. | |
3302 | */ | |
61bd5218 | 3303 | return check_pkt_ptr_alignment(env, reg, off, size, strict); |
d58e468b PP |
3304 | case PTR_TO_FLOW_KEYS: |
3305 | pointer_desc = "flow keys "; | |
3306 | break; | |
f1174f77 EC |
3307 | case PTR_TO_MAP_VALUE: |
3308 | pointer_desc = "value "; | |
3309 | break; | |
3310 | case PTR_TO_CTX: | |
3311 | pointer_desc = "context "; | |
3312 | break; | |
3313 | case PTR_TO_STACK: | |
3314 | pointer_desc = "stack "; | |
01f810ac AM |
3315 | /* The stack spill tracking logic in check_stack_write_fixed_off() |
3316 | * and check_stack_read_fixed_off() relies on stack accesses being | |
a5ec6ae1 JH |
3317 | * aligned. |
3318 | */ | |
3319 | strict = true; | |
f1174f77 | 3320 | break; |
c64b7983 JS |
3321 | case PTR_TO_SOCKET: |
3322 | pointer_desc = "sock "; | |
3323 | break; | |
46f8bc92 MKL |
3324 | case PTR_TO_SOCK_COMMON: |
3325 | pointer_desc = "sock_common "; | |
3326 | break; | |
655a51e5 MKL |
3327 | case PTR_TO_TCP_SOCK: |
3328 | pointer_desc = "tcp_sock "; | |
3329 | break; | |
fada7fdc JL |
3330 | case PTR_TO_XDP_SOCK: |
3331 | pointer_desc = "xdp_sock "; | |
3332 | break; | |
79adffcd | 3333 | default: |
f1174f77 | 3334 | break; |
79adffcd | 3335 | } |
61bd5218 JK |
3336 | return check_generic_ptr_alignment(env, reg, pointer_desc, off, size, |
3337 | strict); | |
79adffcd DB |
3338 | } |
3339 | ||
f4d7e40a AS |
3340 | static int update_stack_depth(struct bpf_verifier_env *env, |
3341 | const struct bpf_func_state *func, | |
3342 | int off) | |
3343 | { | |
9c8105bd | 3344 | u16 stack = env->subprog_info[func->subprogno].stack_depth; |
f4d7e40a AS |
3345 | |
3346 | if (stack >= -off) | |
3347 | return 0; | |
3348 | ||
3349 | /* update known max for given subprogram */ | |
9c8105bd | 3350 | env->subprog_info[func->subprogno].stack_depth = -off; |
70a87ffe AS |
3351 | return 0; |
3352 | } | |
f4d7e40a | 3353 | |
70a87ffe AS |
3354 | /* starting from main bpf function walk all instructions of the function |
3355 | * and recursively walk all callees that given function can call. | |
3356 | * Ignore jump and exit insns. | |
3357 | * Since recursion is prevented by check_cfg() this algorithm | |
3358 | * only needs a local stack of MAX_CALL_FRAMES to remember callsites | |
3359 | */ | |
3360 | static int check_max_stack_depth(struct bpf_verifier_env *env) | |
3361 | { | |
9c8105bd JW |
3362 | int depth = 0, frame = 0, idx = 0, i = 0, subprog_end; |
3363 | struct bpf_subprog_info *subprog = env->subprog_info; | |
70a87ffe | 3364 | struct bpf_insn *insn = env->prog->insnsi; |
ebf7d1f5 | 3365 | bool tail_call_reachable = false; |
70a87ffe AS |
3366 | int ret_insn[MAX_CALL_FRAMES]; |
3367 | int ret_prog[MAX_CALL_FRAMES]; | |
ebf7d1f5 | 3368 | int j; |
f4d7e40a | 3369 | |
70a87ffe | 3370 | process_func: |
7f6e4312 MF |
3371 | /* protect against potential stack overflow that might happen when |
3372 | * bpf2bpf calls get combined with tailcalls. Limit the caller's stack | |
3373 | * depth for such case down to 256 so that the worst case scenario | |
3374 | * would result in 8k stack size (32 which is tailcall limit * 256 = | |
3375 | * 8k). | |
3376 | * | |
3377 | * To get the idea what might happen, see an example: | |
3378 | * func1 -> sub rsp, 128 | |
3379 | * subfunc1 -> sub rsp, 256 | |
3380 | * tailcall1 -> add rsp, 256 | |
3381 | * func2 -> sub rsp, 192 (total stack size = 128 + 192 = 320) | |
3382 | * subfunc2 -> sub rsp, 64 | |
3383 | * subfunc22 -> sub rsp, 128 | |
3384 | * tailcall2 -> add rsp, 128 | |
3385 | * func3 -> sub rsp, 32 (total stack size 128 + 192 + 64 + 32 = 416) | |
3386 | * | |
3387 | * tailcall will unwind the current stack frame but it will not get rid | |
3388 | * of caller's stack as shown on the example above. | |
3389 | */ | |
3390 | if (idx && subprog[idx].has_tail_call && depth >= 256) { | |
3391 | verbose(env, | |
3392 | "tail_calls are not allowed when call stack of previous frames is %d bytes. Too large\n", | |
3393 | depth); | |
3394 | return -EACCES; | |
3395 | } | |
70a87ffe AS |
3396 | /* round up to 32-bytes, since this is granularity |
3397 | * of interpreter stack size | |
3398 | */ | |
9c8105bd | 3399 | depth += round_up(max_t(u32, subprog[idx].stack_depth, 1), 32); |
70a87ffe | 3400 | if (depth > MAX_BPF_STACK) { |
f4d7e40a | 3401 | verbose(env, "combined stack size of %d calls is %d. Too large\n", |
70a87ffe | 3402 | frame + 1, depth); |
f4d7e40a AS |
3403 | return -EACCES; |
3404 | } | |
70a87ffe | 3405 | continue_func: |
4cb3d99c | 3406 | subprog_end = subprog[idx + 1].start; |
70a87ffe | 3407 | for (; i < subprog_end; i++) { |
23a2d70c | 3408 | if (!bpf_pseudo_call(insn + i)) |
70a87ffe AS |
3409 | continue; |
3410 | /* remember insn and function to return to */ | |
3411 | ret_insn[frame] = i + 1; | |
9c8105bd | 3412 | ret_prog[frame] = idx; |
70a87ffe AS |
3413 | |
3414 | /* find the callee */ | |
3415 | i = i + insn[i].imm + 1; | |
9c8105bd JW |
3416 | idx = find_subprog(env, i); |
3417 | if (idx < 0) { | |
70a87ffe AS |
3418 | WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", |
3419 | i); | |
3420 | return -EFAULT; | |
3421 | } | |
ebf7d1f5 MF |
3422 | |
3423 | if (subprog[idx].has_tail_call) | |
3424 | tail_call_reachable = true; | |
3425 | ||
70a87ffe AS |
3426 | frame++; |
3427 | if (frame >= MAX_CALL_FRAMES) { | |
927cb781 PC |
3428 | verbose(env, "the call stack of %d frames is too deep !\n", |
3429 | frame); | |
3430 | return -E2BIG; | |
70a87ffe AS |
3431 | } |
3432 | goto process_func; | |
3433 | } | |
ebf7d1f5 MF |
3434 | /* if tail call got detected across bpf2bpf calls then mark each of the |
3435 | * currently present subprog frames as tail call reachable subprogs; | |
3436 | * this info will be utilized by JIT so that we will be preserving the | |
3437 | * tail call counter throughout bpf2bpf calls combined with tailcalls | |
3438 | */ | |
3439 | if (tail_call_reachable) | |
3440 | for (j = 0; j < frame; j++) | |
3441 | subprog[ret_prog[j]].tail_call_reachable = true; | |
3442 | ||
70a87ffe AS |
3443 | /* end of for() loop means the last insn of the 'subprog' |
3444 | * was reached. Doesn't matter whether it was JA or EXIT | |
3445 | */ | |
3446 | if (frame == 0) | |
3447 | return 0; | |
9c8105bd | 3448 | depth -= round_up(max_t(u32, subprog[idx].stack_depth, 1), 32); |
70a87ffe AS |
3449 | frame--; |
3450 | i = ret_insn[frame]; | |
9c8105bd | 3451 | idx = ret_prog[frame]; |
70a87ffe | 3452 | goto continue_func; |
f4d7e40a AS |
3453 | } |
3454 | ||
19d28fbd | 3455 | #ifndef CONFIG_BPF_JIT_ALWAYS_ON |
1ea47e01 AS |
3456 | static int get_callee_stack_depth(struct bpf_verifier_env *env, |
3457 | const struct bpf_insn *insn, int idx) | |
3458 | { | |
3459 | int start = idx + insn->imm + 1, subprog; | |
3460 | ||
3461 | subprog = find_subprog(env, start); | |
3462 | if (subprog < 0) { | |
3463 | WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", | |
3464 | start); | |
3465 | return -EFAULT; | |
3466 | } | |
9c8105bd | 3467 | return env->subprog_info[subprog].stack_depth; |
1ea47e01 | 3468 | } |
19d28fbd | 3469 | #endif |
1ea47e01 | 3470 | |
51c39bb1 AS |
3471 | int check_ctx_reg(struct bpf_verifier_env *env, |
3472 | const struct bpf_reg_state *reg, int regno) | |
58990d1f DB |
3473 | { |
3474 | /* Access to ctx or passing it to a helper is only allowed in | |
3475 | * its original, unmodified form. | |
3476 | */ | |
3477 | ||
3478 | if (reg->off) { | |
3479 | verbose(env, "dereference of modified ctx ptr R%d off=%d disallowed\n", | |
3480 | regno, reg->off); | |
3481 | return -EACCES; | |
3482 | } | |
3483 | ||
3484 | if (!tnum_is_const(reg->var_off) || reg->var_off.value) { | |
3485 | char tn_buf[48]; | |
3486 | ||
3487 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
3488 | verbose(env, "variable ctx access var_off=%s disallowed\n", tn_buf); | |
3489 | return -EACCES; | |
3490 | } | |
3491 | ||
3492 | return 0; | |
3493 | } | |
3494 | ||
afbf21dc YS |
3495 | static int __check_buffer_access(struct bpf_verifier_env *env, |
3496 | const char *buf_info, | |
3497 | const struct bpf_reg_state *reg, | |
3498 | int regno, int off, int size) | |
9df1c28b MM |
3499 | { |
3500 | if (off < 0) { | |
3501 | verbose(env, | |
4fc00b79 | 3502 | "R%d invalid %s buffer access: off=%d, size=%d\n", |
afbf21dc | 3503 | regno, buf_info, off, size); |
9df1c28b MM |
3504 | return -EACCES; |
3505 | } | |
3506 | if (!tnum_is_const(reg->var_off) || reg->var_off.value) { | |
3507 | char tn_buf[48]; | |
3508 | ||
3509 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
3510 | verbose(env, | |
4fc00b79 | 3511 | "R%d invalid variable buffer offset: off=%d, var_off=%s\n", |
9df1c28b MM |
3512 | regno, off, tn_buf); |
3513 | return -EACCES; | |
3514 | } | |
afbf21dc YS |
3515 | |
3516 | return 0; | |
3517 | } | |
3518 | ||
3519 | static int check_tp_buffer_access(struct bpf_verifier_env *env, | |
3520 | const struct bpf_reg_state *reg, | |
3521 | int regno, int off, int size) | |
3522 | { | |
3523 | int err; | |
3524 | ||
3525 | err = __check_buffer_access(env, "tracepoint", reg, regno, off, size); | |
3526 | if (err) | |
3527 | return err; | |
3528 | ||
9df1c28b MM |
3529 | if (off + size > env->prog->aux->max_tp_access) |
3530 | env->prog->aux->max_tp_access = off + size; | |
3531 | ||
3532 | return 0; | |
3533 | } | |
3534 | ||
afbf21dc YS |
3535 | static int check_buffer_access(struct bpf_verifier_env *env, |
3536 | const struct bpf_reg_state *reg, | |
3537 | int regno, int off, int size, | |
3538 | bool zero_size_allowed, | |
3539 | const char *buf_info, | |
3540 | u32 *max_access) | |
3541 | { | |
3542 | int err; | |
3543 | ||
3544 | err = __check_buffer_access(env, buf_info, reg, regno, off, size); | |
3545 | if (err) | |
3546 | return err; | |
3547 | ||
3548 | if (off + size > *max_access) | |
3549 | *max_access = off + size; | |
3550 | ||
3551 | return 0; | |
3552 | } | |
3553 | ||
3f50f132 JF |
3554 | /* BPF architecture zero extends alu32 ops into 64-bit registesr */ |
3555 | static void zext_32_to_64(struct bpf_reg_state *reg) | |
3556 | { | |
3557 | reg->var_off = tnum_subreg(reg->var_off); | |
3558 | __reg_assign_32_into_64(reg); | |
3559 | } | |
9df1c28b | 3560 | |
0c17d1d2 JH |
3561 | /* truncate register to smaller size (in bytes) |
3562 | * must be called with size < BPF_REG_SIZE | |
3563 | */ | |
3564 | static void coerce_reg_to_size(struct bpf_reg_state *reg, int size) | |
3565 | { | |
3566 | u64 mask; | |
3567 | ||
3568 | /* clear high bits in bit representation */ | |
3569 | reg->var_off = tnum_cast(reg->var_off, size); | |
3570 | ||
3571 | /* fix arithmetic bounds */ | |
3572 | mask = ((u64)1 << (size * 8)) - 1; | |
3573 | if ((reg->umin_value & ~mask) == (reg->umax_value & ~mask)) { | |
3574 | reg->umin_value &= mask; | |
3575 | reg->umax_value &= mask; | |
3576 | } else { | |
3577 | reg->umin_value = 0; | |
3578 | reg->umax_value = mask; | |
3579 | } | |
3580 | reg->smin_value = reg->umin_value; | |
3581 | reg->smax_value = reg->umax_value; | |
3f50f132 JF |
3582 | |
3583 | /* If size is smaller than 32bit register the 32bit register | |
3584 | * values are also truncated so we push 64-bit bounds into | |
3585 | * 32-bit bounds. Above were truncated < 32-bits already. | |
3586 | */ | |
3587 | if (size >= 4) | |
3588 | return; | |
3589 | __reg_combine_64_into_32(reg); | |
0c17d1d2 JH |
3590 | } |
3591 | ||
a23740ec AN |
3592 | static bool bpf_map_is_rdonly(const struct bpf_map *map) |
3593 | { | |
3594 | return (map->map_flags & BPF_F_RDONLY_PROG) && map->frozen; | |
3595 | } | |
3596 | ||
3597 | static int bpf_map_direct_read(struct bpf_map *map, int off, int size, u64 *val) | |
3598 | { | |
3599 | void *ptr; | |
3600 | u64 addr; | |
3601 | int err; | |
3602 | ||
3603 | err = map->ops->map_direct_value_addr(map, &addr, off); | |
3604 | if (err) | |
3605 | return err; | |
2dedd7d2 | 3606 | ptr = (void *)(long)addr + off; |
a23740ec AN |
3607 | |
3608 | switch (size) { | |
3609 | case sizeof(u8): | |
3610 | *val = (u64)*(u8 *)ptr; | |
3611 | break; | |
3612 | case sizeof(u16): | |
3613 | *val = (u64)*(u16 *)ptr; | |
3614 | break; | |
3615 | case sizeof(u32): | |
3616 | *val = (u64)*(u32 *)ptr; | |
3617 | break; | |
3618 | case sizeof(u64): | |
3619 | *val = *(u64 *)ptr; | |
3620 | break; | |
3621 | default: | |
3622 | return -EINVAL; | |
3623 | } | |
3624 | return 0; | |
3625 | } | |
3626 | ||
9e15db66 AS |
3627 | static int check_ptr_to_btf_access(struct bpf_verifier_env *env, |
3628 | struct bpf_reg_state *regs, | |
3629 | int regno, int off, int size, | |
3630 | enum bpf_access_type atype, | |
3631 | int value_regno) | |
3632 | { | |
3633 | struct bpf_reg_state *reg = regs + regno; | |
22dc4a0f AN |
3634 | const struct btf_type *t = btf_type_by_id(reg->btf, reg->btf_id); |
3635 | const char *tname = btf_name_by_offset(reg->btf, t->name_off); | |
9e15db66 AS |
3636 | u32 btf_id; |
3637 | int ret; | |
3638 | ||
9e15db66 AS |
3639 | if (off < 0) { |
3640 | verbose(env, | |
3641 | "R%d is ptr_%s invalid negative access: off=%d\n", | |
3642 | regno, tname, off); | |
3643 | return -EACCES; | |
3644 | } | |
3645 | if (!tnum_is_const(reg->var_off) || reg->var_off.value) { | |
3646 | char tn_buf[48]; | |
3647 | ||
3648 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
3649 | verbose(env, | |
3650 | "R%d is ptr_%s invalid variable offset: off=%d, var_off=%s\n", | |
3651 | regno, tname, off, tn_buf); | |
3652 | return -EACCES; | |
3653 | } | |
3654 | ||
27ae7997 | 3655 | if (env->ops->btf_struct_access) { |
22dc4a0f AN |
3656 | ret = env->ops->btf_struct_access(&env->log, reg->btf, t, |
3657 | off, size, atype, &btf_id); | |
27ae7997 MKL |
3658 | } else { |
3659 | if (atype != BPF_READ) { | |
3660 | verbose(env, "only read is supported\n"); | |
3661 | return -EACCES; | |
3662 | } | |
3663 | ||
22dc4a0f AN |
3664 | ret = btf_struct_access(&env->log, reg->btf, t, off, size, |
3665 | atype, &btf_id); | |
27ae7997 MKL |
3666 | } |
3667 | ||
9e15db66 AS |
3668 | if (ret < 0) |
3669 | return ret; | |
3670 | ||
41c48f3a | 3671 | if (atype == BPF_READ && value_regno >= 0) |
22dc4a0f | 3672 | mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id); |
41c48f3a AI |
3673 | |
3674 | return 0; | |
3675 | } | |
3676 | ||
3677 | static int check_ptr_to_map_access(struct bpf_verifier_env *env, | |
3678 | struct bpf_reg_state *regs, | |
3679 | int regno, int off, int size, | |
3680 | enum bpf_access_type atype, | |
3681 | int value_regno) | |
3682 | { | |
3683 | struct bpf_reg_state *reg = regs + regno; | |
3684 | struct bpf_map *map = reg->map_ptr; | |
3685 | const struct btf_type *t; | |
3686 | const char *tname; | |
3687 | u32 btf_id; | |
3688 | int ret; | |
3689 | ||
3690 | if (!btf_vmlinux) { | |
3691 | verbose(env, "map_ptr access not supported without CONFIG_DEBUG_INFO_BTF\n"); | |
3692 | return -ENOTSUPP; | |
3693 | } | |
3694 | ||
3695 | if (!map->ops->map_btf_id || !*map->ops->map_btf_id) { | |
3696 | verbose(env, "map_ptr access not supported for map type %d\n", | |
3697 | map->map_type); | |
3698 | return -ENOTSUPP; | |
3699 | } | |
3700 | ||
3701 | t = btf_type_by_id(btf_vmlinux, *map->ops->map_btf_id); | |
3702 | tname = btf_name_by_offset(btf_vmlinux, t->name_off); | |
3703 | ||
3704 | if (!env->allow_ptr_to_map_access) { | |
3705 | verbose(env, | |
3706 | "%s access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN\n", | |
3707 | tname); | |
3708 | return -EPERM; | |
9e15db66 | 3709 | } |
27ae7997 | 3710 | |
41c48f3a AI |
3711 | if (off < 0) { |
3712 | verbose(env, "R%d is %s invalid negative access: off=%d\n", | |
3713 | regno, tname, off); | |
3714 | return -EACCES; | |
3715 | } | |
3716 | ||
3717 | if (atype != BPF_READ) { | |
3718 | verbose(env, "only read from %s is supported\n", tname); | |
3719 | return -EACCES; | |
3720 | } | |
3721 | ||
22dc4a0f | 3722 | ret = btf_struct_access(&env->log, btf_vmlinux, t, off, size, atype, &btf_id); |
41c48f3a AI |
3723 | if (ret < 0) |
3724 | return ret; | |
3725 | ||
3726 | if (value_regno >= 0) | |
22dc4a0f | 3727 | mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id); |
41c48f3a | 3728 | |
9e15db66 AS |
3729 | return 0; |
3730 | } | |
3731 | ||
01f810ac AM |
3732 | /* Check that the stack access at the given offset is within bounds. The |
3733 | * maximum valid offset is -1. | |
3734 | * | |
3735 | * The minimum valid offset is -MAX_BPF_STACK for writes, and | |
3736 | * -state->allocated_stack for reads. | |
3737 | */ | |
3738 | static int check_stack_slot_within_bounds(int off, | |
3739 | struct bpf_func_state *state, | |
3740 | enum bpf_access_type t) | |
3741 | { | |
3742 | int min_valid_off; | |
3743 | ||
3744 | if (t == BPF_WRITE) | |
3745 | min_valid_off = -MAX_BPF_STACK; | |
3746 | else | |
3747 | min_valid_off = -state->allocated_stack; | |
3748 | ||
3749 | if (off < min_valid_off || off > -1) | |
3750 | return -EACCES; | |
3751 | return 0; | |
3752 | } | |
3753 | ||
3754 | /* Check that the stack access at 'regno + off' falls within the maximum stack | |
3755 | * bounds. | |
3756 | * | |
3757 | * 'off' includes `regno->offset`, but not its dynamic part (if any). | |
3758 | */ | |
3759 | static int check_stack_access_within_bounds( | |
3760 | struct bpf_verifier_env *env, | |
3761 | int regno, int off, int access_size, | |
3762 | enum stack_access_src src, enum bpf_access_type type) | |
3763 | { | |
3764 | struct bpf_reg_state *regs = cur_regs(env); | |
3765 | struct bpf_reg_state *reg = regs + regno; | |
3766 | struct bpf_func_state *state = func(env, reg); | |
3767 | int min_off, max_off; | |
3768 | int err; | |
3769 | char *err_extra; | |
3770 | ||
3771 | if (src == ACCESS_HELPER) | |
3772 | /* We don't know if helpers are reading or writing (or both). */ | |
3773 | err_extra = " indirect access to"; | |
3774 | else if (type == BPF_READ) | |
3775 | err_extra = " read from"; | |
3776 | else | |
3777 | err_extra = " write to"; | |
3778 | ||
3779 | if (tnum_is_const(reg->var_off)) { | |
3780 | min_off = reg->var_off.value + off; | |
3781 | if (access_size > 0) | |
3782 | max_off = min_off + access_size - 1; | |
3783 | else | |
3784 | max_off = min_off; | |
3785 | } else { | |
3786 | if (reg->smax_value >= BPF_MAX_VAR_OFF || | |
3787 | reg->smin_value <= -BPF_MAX_VAR_OFF) { | |
3788 | verbose(env, "invalid unbounded variable-offset%s stack R%d\n", | |
3789 | err_extra, regno); | |
3790 | return -EACCES; | |
3791 | } | |
3792 | min_off = reg->smin_value + off; | |
3793 | if (access_size > 0) | |
3794 | max_off = reg->smax_value + off + access_size - 1; | |
3795 | else | |
3796 | max_off = min_off; | |
3797 | } | |
3798 | ||
3799 | err = check_stack_slot_within_bounds(min_off, state, type); | |
3800 | if (!err) | |
3801 | err = check_stack_slot_within_bounds(max_off, state, type); | |
3802 | ||
3803 | if (err) { | |
3804 | if (tnum_is_const(reg->var_off)) { | |
3805 | verbose(env, "invalid%s stack R%d off=%d size=%d\n", | |
3806 | err_extra, regno, off, access_size); | |
3807 | } else { | |
3808 | char tn_buf[48]; | |
3809 | ||
3810 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
3811 | verbose(env, "invalid variable-offset%s stack R%d var_off=%s size=%d\n", | |
3812 | err_extra, regno, tn_buf, access_size); | |
3813 | } | |
3814 | } | |
3815 | return err; | |
3816 | } | |
41c48f3a | 3817 | |
17a52670 AS |
3818 | /* check whether memory at (regno + off) is accessible for t = (read | write) |
3819 | * if t==write, value_regno is a register which value is stored into memory | |
3820 | * if t==read, value_regno is a register which will receive the value from memory | |
3821 | * if t==write && value_regno==-1, some unknown value is stored into memory | |
3822 | * if t==read && value_regno==-1, don't care what we read from memory | |
3823 | */ | |
ca369602 DB |
3824 | static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno, |
3825 | int off, int bpf_size, enum bpf_access_type t, | |
3826 | int value_regno, bool strict_alignment_once) | |
17a52670 | 3827 | { |
638f5b90 AS |
3828 | struct bpf_reg_state *regs = cur_regs(env); |
3829 | struct bpf_reg_state *reg = regs + regno; | |
f4d7e40a | 3830 | struct bpf_func_state *state; |
17a52670 AS |
3831 | int size, err = 0; |
3832 | ||
3833 | size = bpf_size_to_bytes(bpf_size); | |
3834 | if (size < 0) | |
3835 | return size; | |
3836 | ||
f1174f77 | 3837 | /* alignment checks will add in reg->off themselves */ |
ca369602 | 3838 | err = check_ptr_alignment(env, reg, off, size, strict_alignment_once); |
969bf05e AS |
3839 | if (err) |
3840 | return err; | |
17a52670 | 3841 | |
f1174f77 EC |
3842 | /* for access checks, reg->off is just part of off */ |
3843 | off += reg->off; | |
3844 | ||
3845 | if (reg->type == PTR_TO_MAP_VALUE) { | |
1be7f75d AS |
3846 | if (t == BPF_WRITE && value_regno >= 0 && |
3847 | is_pointer_value(env, value_regno)) { | |
61bd5218 | 3848 | verbose(env, "R%d leaks addr into map\n", value_regno); |
1be7f75d AS |
3849 | return -EACCES; |
3850 | } | |
591fe988 DB |
3851 | err = check_map_access_type(env, regno, off, size, t); |
3852 | if (err) | |
3853 | return err; | |
9fd29c08 | 3854 | err = check_map_access(env, regno, off, size, false); |
a23740ec AN |
3855 | if (!err && t == BPF_READ && value_regno >= 0) { |
3856 | struct bpf_map *map = reg->map_ptr; | |
3857 | ||
3858 | /* if map is read-only, track its contents as scalars */ | |
3859 | if (tnum_is_const(reg->var_off) && | |
3860 | bpf_map_is_rdonly(map) && | |
3861 | map->ops->map_direct_value_addr) { | |
3862 | int map_off = off + reg->var_off.value; | |
3863 | u64 val = 0; | |
3864 | ||
3865 | err = bpf_map_direct_read(map, map_off, size, | |
3866 | &val); | |
3867 | if (err) | |
3868 | return err; | |
3869 | ||
3870 | regs[value_regno].type = SCALAR_VALUE; | |
3871 | __mark_reg_known(®s[value_regno], val); | |
3872 | } else { | |
3873 | mark_reg_unknown(env, regs, value_regno); | |
3874 | } | |
3875 | } | |
457f4436 AN |
3876 | } else if (reg->type == PTR_TO_MEM) { |
3877 | if (t == BPF_WRITE && value_regno >= 0 && | |
3878 | is_pointer_value(env, value_regno)) { | |
3879 | verbose(env, "R%d leaks addr into mem\n", value_regno); | |
3880 | return -EACCES; | |
3881 | } | |
3882 | err = check_mem_region_access(env, regno, off, size, | |
3883 | reg->mem_size, false); | |
3884 | if (!err && t == BPF_READ && value_regno >= 0) | |
3885 | mark_reg_unknown(env, regs, value_regno); | |
1a0dc1ac | 3886 | } else if (reg->type == PTR_TO_CTX) { |
f1174f77 | 3887 | enum bpf_reg_type reg_type = SCALAR_VALUE; |
22dc4a0f | 3888 | struct btf *btf = NULL; |
9e15db66 | 3889 | u32 btf_id = 0; |
19de99f7 | 3890 | |
1be7f75d AS |
3891 | if (t == BPF_WRITE && value_regno >= 0 && |
3892 | is_pointer_value(env, value_regno)) { | |
61bd5218 | 3893 | verbose(env, "R%d leaks addr into ctx\n", value_regno); |
1be7f75d AS |
3894 | return -EACCES; |
3895 | } | |
f1174f77 | 3896 | |
58990d1f DB |
3897 | err = check_ctx_reg(env, reg, regno); |
3898 | if (err < 0) | |
3899 | return err; | |
3900 | ||
22dc4a0f | 3901 | err = check_ctx_access(env, insn_idx, off, size, t, ®_type, &btf, &btf_id); |
9e15db66 AS |
3902 | if (err) |
3903 | verbose_linfo(env, insn_idx, "; "); | |
969bf05e | 3904 | if (!err && t == BPF_READ && value_regno >= 0) { |
f1174f77 | 3905 | /* ctx access returns either a scalar, or a |
de8f3a83 DB |
3906 | * PTR_TO_PACKET[_META,_END]. In the latter |
3907 | * case, we know the offset is zero. | |
f1174f77 | 3908 | */ |
46f8bc92 | 3909 | if (reg_type == SCALAR_VALUE) { |
638f5b90 | 3910 | mark_reg_unknown(env, regs, value_regno); |
46f8bc92 | 3911 | } else { |
638f5b90 | 3912 | mark_reg_known_zero(env, regs, |
61bd5218 | 3913 | value_regno); |
46f8bc92 MKL |
3914 | if (reg_type_may_be_null(reg_type)) |
3915 | regs[value_regno].id = ++env->id_gen; | |
5327ed3d JW |
3916 | /* A load of ctx field could have different |
3917 | * actual load size with the one encoded in the | |
3918 | * insn. When the dst is PTR, it is for sure not | |
3919 | * a sub-register. | |
3920 | */ | |
3921 | regs[value_regno].subreg_def = DEF_NOT_SUBREG; | |
b121b341 | 3922 | if (reg_type == PTR_TO_BTF_ID || |
22dc4a0f AN |
3923 | reg_type == PTR_TO_BTF_ID_OR_NULL) { |
3924 | regs[value_regno].btf = btf; | |
9e15db66 | 3925 | regs[value_regno].btf_id = btf_id; |
22dc4a0f | 3926 | } |
46f8bc92 | 3927 | } |
638f5b90 | 3928 | regs[value_regno].type = reg_type; |
969bf05e | 3929 | } |
17a52670 | 3930 | |
f1174f77 | 3931 | } else if (reg->type == PTR_TO_STACK) { |
01f810ac AM |
3932 | /* Basic bounds checks. */ |
3933 | err = check_stack_access_within_bounds(env, regno, off, size, ACCESS_DIRECT, t); | |
e4298d25 DB |
3934 | if (err) |
3935 | return err; | |
8726679a | 3936 | |
f4d7e40a AS |
3937 | state = func(env, reg); |
3938 | err = update_stack_depth(env, state, off); | |
3939 | if (err) | |
3940 | return err; | |
8726679a | 3941 | |
01f810ac AM |
3942 | if (t == BPF_READ) |
3943 | err = check_stack_read(env, regno, off, size, | |
61bd5218 | 3944 | value_regno); |
01f810ac AM |
3945 | else |
3946 | err = check_stack_write(env, regno, off, size, | |
3947 | value_regno, insn_idx); | |
de8f3a83 | 3948 | } else if (reg_is_pkt_pointer(reg)) { |
3a0af8fd | 3949 | if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) { |
61bd5218 | 3950 | verbose(env, "cannot write into packet\n"); |
969bf05e AS |
3951 | return -EACCES; |
3952 | } | |
4acf6c0b BB |
3953 | if (t == BPF_WRITE && value_regno >= 0 && |
3954 | is_pointer_value(env, value_regno)) { | |
61bd5218 JK |
3955 | verbose(env, "R%d leaks addr into packet\n", |
3956 | value_regno); | |
4acf6c0b BB |
3957 | return -EACCES; |
3958 | } | |
9fd29c08 | 3959 | err = check_packet_access(env, regno, off, size, false); |
969bf05e | 3960 | if (!err && t == BPF_READ && value_regno >= 0) |
638f5b90 | 3961 | mark_reg_unknown(env, regs, value_regno); |
d58e468b PP |
3962 | } else if (reg->type == PTR_TO_FLOW_KEYS) { |
3963 | if (t == BPF_WRITE && value_regno >= 0 && | |
3964 | is_pointer_value(env, value_regno)) { | |
3965 | verbose(env, "R%d leaks addr into flow keys\n", | |
3966 | value_regno); | |
3967 | return -EACCES; | |
3968 | } | |
3969 | ||
3970 | err = check_flow_keys_access(env, off, size); | |
3971 | if (!err && t == BPF_READ && value_regno >= 0) | |
3972 | mark_reg_unknown(env, regs, value_regno); | |
46f8bc92 | 3973 | } else if (type_is_sk_pointer(reg->type)) { |
c64b7983 | 3974 | if (t == BPF_WRITE) { |
46f8bc92 MKL |
3975 | verbose(env, "R%d cannot write into %s\n", |
3976 | regno, reg_type_str[reg->type]); | |
c64b7983 JS |
3977 | return -EACCES; |
3978 | } | |
5f456649 | 3979 | err = check_sock_access(env, insn_idx, regno, off, size, t); |
c64b7983 JS |
3980 | if (!err && value_regno >= 0) |
3981 | mark_reg_unknown(env, regs, value_regno); | |
9df1c28b MM |
3982 | } else if (reg->type == PTR_TO_TP_BUFFER) { |
3983 | err = check_tp_buffer_access(env, reg, regno, off, size); | |
3984 | if (!err && t == BPF_READ && value_regno >= 0) | |
3985 | mark_reg_unknown(env, regs, value_regno); | |
9e15db66 AS |
3986 | } else if (reg->type == PTR_TO_BTF_ID) { |
3987 | err = check_ptr_to_btf_access(env, regs, regno, off, size, t, | |
3988 | value_regno); | |
41c48f3a AI |
3989 | } else if (reg->type == CONST_PTR_TO_MAP) { |
3990 | err = check_ptr_to_map_access(env, regs, regno, off, size, t, | |
3991 | value_regno); | |
afbf21dc YS |
3992 | } else if (reg->type == PTR_TO_RDONLY_BUF) { |
3993 | if (t == BPF_WRITE) { | |
3994 | verbose(env, "R%d cannot write into %s\n", | |
3995 | regno, reg_type_str[reg->type]); | |
3996 | return -EACCES; | |
3997 | } | |
f6dfbe31 CIK |
3998 | err = check_buffer_access(env, reg, regno, off, size, false, |
3999 | "rdonly", | |
afbf21dc YS |
4000 | &env->prog->aux->max_rdonly_access); |
4001 | if (!err && value_regno >= 0) | |
4002 | mark_reg_unknown(env, regs, value_regno); | |
4003 | } else if (reg->type == PTR_TO_RDWR_BUF) { | |
f6dfbe31 CIK |
4004 | err = check_buffer_access(env, reg, regno, off, size, false, |
4005 | "rdwr", | |
afbf21dc YS |
4006 | &env->prog->aux->max_rdwr_access); |
4007 | if (!err && t == BPF_READ && value_regno >= 0) | |
4008 | mark_reg_unknown(env, regs, value_regno); | |
17a52670 | 4009 | } else { |
61bd5218 JK |
4010 | verbose(env, "R%d invalid mem access '%s'\n", regno, |
4011 | reg_type_str[reg->type]); | |
17a52670 AS |
4012 | return -EACCES; |
4013 | } | |
969bf05e | 4014 | |
f1174f77 | 4015 | if (!err && size < BPF_REG_SIZE && value_regno >= 0 && t == BPF_READ && |
638f5b90 | 4016 | regs[value_regno].type == SCALAR_VALUE) { |
f1174f77 | 4017 | /* b/h/w load zero-extends, mark upper bits as known 0 */ |
0c17d1d2 | 4018 | coerce_reg_to_size(®s[value_regno], size); |
969bf05e | 4019 | } |
17a52670 AS |
4020 | return err; |
4021 | } | |
4022 | ||
91c960b0 | 4023 | static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_insn *insn) |
17a52670 | 4024 | { |
5ffa2550 | 4025 | int load_reg; |
17a52670 AS |
4026 | int err; |
4027 | ||
5ca419f2 BJ |
4028 | switch (insn->imm) { |
4029 | case BPF_ADD: | |
4030 | case BPF_ADD | BPF_FETCH: | |
981f94c3 BJ |
4031 | case BPF_AND: |
4032 | case BPF_AND | BPF_FETCH: | |
4033 | case BPF_OR: | |
4034 | case BPF_OR | BPF_FETCH: | |
4035 | case BPF_XOR: | |
4036 | case BPF_XOR | BPF_FETCH: | |
5ffa2550 BJ |
4037 | case BPF_XCHG: |
4038 | case BPF_CMPXCHG: | |
5ca419f2 BJ |
4039 | break; |
4040 | default: | |
91c960b0 BJ |
4041 | verbose(env, "BPF_ATOMIC uses invalid atomic opcode %02x\n", insn->imm); |
4042 | return -EINVAL; | |
4043 | } | |
4044 | ||
4045 | if (BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) { | |
4046 | verbose(env, "invalid atomic operand size\n"); | |
17a52670 AS |
4047 | return -EINVAL; |
4048 | } | |
4049 | ||
4050 | /* check src1 operand */ | |
dc503a8a | 4051 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
4052 | if (err) |
4053 | return err; | |
4054 | ||
4055 | /* check src2 operand */ | |
dc503a8a | 4056 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
4057 | if (err) |
4058 | return err; | |
4059 | ||
5ffa2550 BJ |
4060 | if (insn->imm == BPF_CMPXCHG) { |
4061 | /* Check comparison of R0 with memory location */ | |
4062 | err = check_reg_arg(env, BPF_REG_0, SRC_OP); | |
4063 | if (err) | |
4064 | return err; | |
4065 | } | |
4066 | ||
6bdf6abc | 4067 | if (is_pointer_value(env, insn->src_reg)) { |
61bd5218 | 4068 | verbose(env, "R%d leaks addr into mem\n", insn->src_reg); |
6bdf6abc DB |
4069 | return -EACCES; |
4070 | } | |
4071 | ||
ca369602 | 4072 | if (is_ctx_reg(env, insn->dst_reg) || |
4b5defde | 4073 | is_pkt_reg(env, insn->dst_reg) || |
46f8bc92 MKL |
4074 | is_flow_key_reg(env, insn->dst_reg) || |
4075 | is_sk_reg(env, insn->dst_reg)) { | |
91c960b0 | 4076 | verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n", |
2a159c6f DB |
4077 | insn->dst_reg, |
4078 | reg_type_str[reg_state(env, insn->dst_reg)->type]); | |
f37a8cb8 DB |
4079 | return -EACCES; |
4080 | } | |
4081 | ||
37086bfd BJ |
4082 | if (insn->imm & BPF_FETCH) { |
4083 | if (insn->imm == BPF_CMPXCHG) | |
4084 | load_reg = BPF_REG_0; | |
4085 | else | |
4086 | load_reg = insn->src_reg; | |
4087 | ||
4088 | /* check and record load of old value */ | |
4089 | err = check_reg_arg(env, load_reg, DST_OP); | |
4090 | if (err) | |
4091 | return err; | |
4092 | } else { | |
4093 | /* This instruction accesses a memory location but doesn't | |
4094 | * actually load it into a register. | |
4095 | */ | |
4096 | load_reg = -1; | |
4097 | } | |
4098 | ||
91c960b0 | 4099 | /* check whether we can read the memory */ |
31fd8581 | 4100 | err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off, |
37086bfd | 4101 | BPF_SIZE(insn->code), BPF_READ, load_reg, true); |
17a52670 AS |
4102 | if (err) |
4103 | return err; | |
4104 | ||
91c960b0 | 4105 | /* check whether we can write into the same memory */ |
5ca419f2 BJ |
4106 | err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off, |
4107 | BPF_SIZE(insn->code), BPF_WRITE, -1, true); | |
4108 | if (err) | |
4109 | return err; | |
4110 | ||
5ca419f2 | 4111 | return 0; |
17a52670 AS |
4112 | } |
4113 | ||
01f810ac AM |
4114 | /* When register 'regno' is used to read the stack (either directly or through |
4115 | * a helper function) make sure that it's within stack boundary and, depending | |
4116 | * on the access type, that all elements of the stack are initialized. | |
4117 | * | |
4118 | * 'off' includes 'regno->off', but not its dynamic part (if any). | |
4119 | * | |
4120 | * All registers that have been spilled on the stack in the slots within the | |
4121 | * read offsets are marked as read. | |
4122 | */ | |
4123 | static int check_stack_range_initialized( | |
4124 | struct bpf_verifier_env *env, int regno, int off, | |
4125 | int access_size, bool zero_size_allowed, | |
4126 | enum stack_access_src type, struct bpf_call_arg_meta *meta) | |
2011fccf AI |
4127 | { |
4128 | struct bpf_reg_state *reg = reg_state(env, regno); | |
01f810ac AM |
4129 | struct bpf_func_state *state = func(env, reg); |
4130 | int err, min_off, max_off, i, j, slot, spi; | |
4131 | char *err_extra = type == ACCESS_HELPER ? " indirect" : ""; | |
4132 | enum bpf_access_type bounds_check_type; | |
4133 | /* Some accesses can write anything into the stack, others are | |
4134 | * read-only. | |
4135 | */ | |
4136 | bool clobber = false; | |
2011fccf | 4137 | |
01f810ac AM |
4138 | if (access_size == 0 && !zero_size_allowed) { |
4139 | verbose(env, "invalid zero-sized read\n"); | |
2011fccf AI |
4140 | return -EACCES; |
4141 | } | |
2011fccf | 4142 | |
01f810ac AM |
4143 | if (type == ACCESS_HELPER) { |
4144 | /* The bounds checks for writes are more permissive than for | |
4145 | * reads. However, if raw_mode is not set, we'll do extra | |
4146 | * checks below. | |
4147 | */ | |
4148 | bounds_check_type = BPF_WRITE; | |
4149 | clobber = true; | |
4150 | } else { | |
4151 | bounds_check_type = BPF_READ; | |
4152 | } | |
4153 | err = check_stack_access_within_bounds(env, regno, off, access_size, | |
4154 | type, bounds_check_type); | |
4155 | if (err) | |
4156 | return err; | |
4157 | ||
17a52670 | 4158 | |
2011fccf | 4159 | if (tnum_is_const(reg->var_off)) { |
01f810ac | 4160 | min_off = max_off = reg->var_off.value + off; |
2011fccf | 4161 | } else { |
088ec26d AI |
4162 | /* Variable offset is prohibited for unprivileged mode for |
4163 | * simplicity since it requires corresponding support in | |
4164 | * Spectre masking for stack ALU. | |
4165 | * See also retrieve_ptr_limit(). | |
4166 | */ | |
2c78ee89 | 4167 | if (!env->bypass_spec_v1) { |
088ec26d | 4168 | char tn_buf[48]; |
f1174f77 | 4169 | |
088ec26d | 4170 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); |
01f810ac AM |
4171 | verbose(env, "R%d%s variable offset stack access prohibited for !root, var_off=%s\n", |
4172 | regno, err_extra, tn_buf); | |
088ec26d AI |
4173 | return -EACCES; |
4174 | } | |
f2bcd05e AI |
4175 | /* Only initialized buffer on stack is allowed to be accessed |
4176 | * with variable offset. With uninitialized buffer it's hard to | |
4177 | * guarantee that whole memory is marked as initialized on | |
4178 | * helper return since specific bounds are unknown what may | |
4179 | * cause uninitialized stack leaking. | |
4180 | */ | |
4181 | if (meta && meta->raw_mode) | |
4182 | meta = NULL; | |
4183 | ||
01f810ac AM |
4184 | min_off = reg->smin_value + off; |
4185 | max_off = reg->smax_value + off; | |
17a52670 AS |
4186 | } |
4187 | ||
435faee1 DB |
4188 | if (meta && meta->raw_mode) { |
4189 | meta->access_size = access_size; | |
4190 | meta->regno = regno; | |
4191 | return 0; | |
4192 | } | |
4193 | ||
2011fccf | 4194 | for (i = min_off; i < max_off + access_size; i++) { |
cc2b14d5 AS |
4195 | u8 *stype; |
4196 | ||
2011fccf | 4197 | slot = -i - 1; |
638f5b90 | 4198 | spi = slot / BPF_REG_SIZE; |
cc2b14d5 AS |
4199 | if (state->allocated_stack <= slot) |
4200 | goto err; | |
4201 | stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE]; | |
4202 | if (*stype == STACK_MISC) | |
4203 | goto mark; | |
4204 | if (*stype == STACK_ZERO) { | |
01f810ac AM |
4205 | if (clobber) { |
4206 | /* helper can write anything into the stack */ | |
4207 | *stype = STACK_MISC; | |
4208 | } | |
cc2b14d5 | 4209 | goto mark; |
17a52670 | 4210 | } |
1d68f22b YS |
4211 | |
4212 | if (state->stack[spi].slot_type[0] == STACK_SPILL && | |
4213 | state->stack[spi].spilled_ptr.type == PTR_TO_BTF_ID) | |
4214 | goto mark; | |
4215 | ||
f7cf25b2 | 4216 | if (state->stack[spi].slot_type[0] == STACK_SPILL && |
cd17d38f YS |
4217 | (state->stack[spi].spilled_ptr.type == SCALAR_VALUE || |
4218 | env->allow_ptr_leaks)) { | |
01f810ac AM |
4219 | if (clobber) { |
4220 | __mark_reg_unknown(env, &state->stack[spi].spilled_ptr); | |
4221 | for (j = 0; j < BPF_REG_SIZE; j++) | |
4222 | state->stack[spi].slot_type[j] = STACK_MISC; | |
4223 | } | |
f7cf25b2 AS |
4224 | goto mark; |
4225 | } | |
4226 | ||
cc2b14d5 | 4227 | err: |
2011fccf | 4228 | if (tnum_is_const(reg->var_off)) { |
01f810ac AM |
4229 | verbose(env, "invalid%s read from stack R%d off %d+%d size %d\n", |
4230 | err_extra, regno, min_off, i - min_off, access_size); | |
2011fccf AI |
4231 | } else { |
4232 | char tn_buf[48]; | |
4233 | ||
4234 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
01f810ac AM |
4235 | verbose(env, "invalid%s read from stack R%d var_off %s+%d size %d\n", |
4236 | err_extra, regno, tn_buf, i - min_off, access_size); | |
2011fccf | 4237 | } |
cc2b14d5 AS |
4238 | return -EACCES; |
4239 | mark: | |
4240 | /* reading any byte out of 8-byte 'spill_slot' will cause | |
4241 | * the whole slot to be marked as 'read' | |
4242 | */ | |
679c782d | 4243 | mark_reg_read(env, &state->stack[spi].spilled_ptr, |
5327ed3d JW |
4244 | state->stack[spi].spilled_ptr.parent, |
4245 | REG_LIVE_READ64); | |
17a52670 | 4246 | } |
2011fccf | 4247 | return update_stack_depth(env, state, min_off); |
17a52670 AS |
4248 | } |
4249 | ||
06c1c049 GB |
4250 | static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, |
4251 | int access_size, bool zero_size_allowed, | |
4252 | struct bpf_call_arg_meta *meta) | |
4253 | { | |
638f5b90 | 4254 | struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; |
06c1c049 | 4255 | |
f1174f77 | 4256 | switch (reg->type) { |
06c1c049 | 4257 | case PTR_TO_PACKET: |
de8f3a83 | 4258 | case PTR_TO_PACKET_META: |
9fd29c08 YS |
4259 | return check_packet_access(env, regno, reg->off, access_size, |
4260 | zero_size_allowed); | |
06c1c049 | 4261 | case PTR_TO_MAP_VALUE: |
591fe988 DB |
4262 | if (check_map_access_type(env, regno, reg->off, access_size, |
4263 | meta && meta->raw_mode ? BPF_WRITE : | |
4264 | BPF_READ)) | |
4265 | return -EACCES; | |
9fd29c08 YS |
4266 | return check_map_access(env, regno, reg->off, access_size, |
4267 | zero_size_allowed); | |
457f4436 AN |
4268 | case PTR_TO_MEM: |
4269 | return check_mem_region_access(env, regno, reg->off, | |
4270 | access_size, reg->mem_size, | |
4271 | zero_size_allowed); | |
afbf21dc YS |
4272 | case PTR_TO_RDONLY_BUF: |
4273 | if (meta && meta->raw_mode) | |
4274 | return -EACCES; | |
4275 | return check_buffer_access(env, reg, regno, reg->off, | |
4276 | access_size, zero_size_allowed, | |
4277 | "rdonly", | |
4278 | &env->prog->aux->max_rdonly_access); | |
4279 | case PTR_TO_RDWR_BUF: | |
4280 | return check_buffer_access(env, reg, regno, reg->off, | |
4281 | access_size, zero_size_allowed, | |
4282 | "rdwr", | |
4283 | &env->prog->aux->max_rdwr_access); | |
0d004c02 | 4284 | case PTR_TO_STACK: |
01f810ac AM |
4285 | return check_stack_range_initialized( |
4286 | env, | |
4287 | regno, reg->off, access_size, | |
4288 | zero_size_allowed, ACCESS_HELPER, meta); | |
0d004c02 LB |
4289 | default: /* scalar_value or invalid ptr */ |
4290 | /* Allow zero-byte read from NULL, regardless of pointer type */ | |
4291 | if (zero_size_allowed && access_size == 0 && | |
4292 | register_is_null(reg)) | |
4293 | return 0; | |
4294 | ||
4295 | verbose(env, "R%d type=%s expected=%s\n", regno, | |
4296 | reg_type_str[reg->type], | |
4297 | reg_type_str[PTR_TO_STACK]); | |
4298 | return -EACCES; | |
06c1c049 GB |
4299 | } |
4300 | } | |
4301 | ||
e5069b9c DB |
4302 | int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg, |
4303 | u32 regno, u32 mem_size) | |
4304 | { | |
4305 | if (register_is_null(reg)) | |
4306 | return 0; | |
4307 | ||
4308 | if (reg_type_may_be_null(reg->type)) { | |
4309 | /* Assuming that the register contains a value check if the memory | |
4310 | * access is safe. Temporarily save and restore the register's state as | |
4311 | * the conversion shouldn't be visible to a caller. | |
4312 | */ | |
4313 | const struct bpf_reg_state saved_reg = *reg; | |
4314 | int rv; | |
4315 | ||
4316 | mark_ptr_not_null_reg(reg); | |
4317 | rv = check_helper_mem_access(env, regno, mem_size, true, NULL); | |
4318 | *reg = saved_reg; | |
4319 | return rv; | |
4320 | } | |
4321 | ||
4322 | return check_helper_mem_access(env, regno, mem_size, true, NULL); | |
4323 | } | |
4324 | ||
d83525ca AS |
4325 | /* Implementation details: |
4326 | * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL | |
4327 | * Two bpf_map_lookups (even with the same key) will have different reg->id. | |
4328 | * For traditional PTR_TO_MAP_VALUE the verifier clears reg->id after | |
4329 | * value_or_null->value transition, since the verifier only cares about | |
4330 | * the range of access to valid map value pointer and doesn't care about actual | |
4331 | * address of the map element. | |
4332 | * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps | |
4333 | * reg->id > 0 after value_or_null->value transition. By doing so | |
4334 | * two bpf_map_lookups will be considered two different pointers that | |
4335 | * point to different bpf_spin_locks. | |
4336 | * The verifier allows taking only one bpf_spin_lock at a time to avoid | |
4337 | * dead-locks. | |
4338 | * Since only one bpf_spin_lock is allowed the checks are simpler than | |
4339 | * reg_is_refcounted() logic. The verifier needs to remember only | |
4340 | * one spin_lock instead of array of acquired_refs. | |
4341 | * cur_state->active_spin_lock remembers which map value element got locked | |
4342 | * and clears it after bpf_spin_unlock. | |
4343 | */ | |
4344 | static int process_spin_lock(struct bpf_verifier_env *env, int regno, | |
4345 | bool is_lock) | |
4346 | { | |
4347 | struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; | |
4348 | struct bpf_verifier_state *cur = env->cur_state; | |
4349 | bool is_const = tnum_is_const(reg->var_off); | |
4350 | struct bpf_map *map = reg->map_ptr; | |
4351 | u64 val = reg->var_off.value; | |
4352 | ||
d83525ca AS |
4353 | if (!is_const) { |
4354 | verbose(env, | |
4355 | "R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n", | |
4356 | regno); | |
4357 | return -EINVAL; | |
4358 | } | |
4359 | if (!map->btf) { | |
4360 | verbose(env, | |
4361 | "map '%s' has to have BTF in order to use bpf_spin_lock\n", | |
4362 | map->name); | |
4363 | return -EINVAL; | |
4364 | } | |
4365 | if (!map_value_has_spin_lock(map)) { | |
4366 | if (map->spin_lock_off == -E2BIG) | |
4367 | verbose(env, | |
4368 | "map '%s' has more than one 'struct bpf_spin_lock'\n", | |
4369 | map->name); | |
4370 | else if (map->spin_lock_off == -ENOENT) | |
4371 | verbose(env, | |
4372 | "map '%s' doesn't have 'struct bpf_spin_lock'\n", | |
4373 | map->name); | |
4374 | else | |
4375 | verbose(env, | |
4376 | "map '%s' is not a struct type or bpf_spin_lock is mangled\n", | |
4377 | map->name); | |
4378 | return -EINVAL; | |
4379 | } | |
4380 | if (map->spin_lock_off != val + reg->off) { | |
4381 | verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock'\n", | |
4382 | val + reg->off); | |
4383 | return -EINVAL; | |
4384 | } | |
4385 | if (is_lock) { | |
4386 | if (cur->active_spin_lock) { | |
4387 | verbose(env, | |
4388 | "Locking two bpf_spin_locks are not allowed\n"); | |
4389 | return -EINVAL; | |
4390 | } | |
4391 | cur->active_spin_lock = reg->id; | |
4392 | } else { | |
4393 | if (!cur->active_spin_lock) { | |
4394 | verbose(env, "bpf_spin_unlock without taking a lock\n"); | |
4395 | return -EINVAL; | |
4396 | } | |
4397 | if (cur->active_spin_lock != reg->id) { | |
4398 | verbose(env, "bpf_spin_unlock of different lock\n"); | |
4399 | return -EINVAL; | |
4400 | } | |
4401 | cur->active_spin_lock = 0; | |
4402 | } | |
4403 | return 0; | |
4404 | } | |
4405 | ||
90133415 DB |
4406 | static bool arg_type_is_mem_ptr(enum bpf_arg_type type) |
4407 | { | |
4408 | return type == ARG_PTR_TO_MEM || | |
4409 | type == ARG_PTR_TO_MEM_OR_NULL || | |
4410 | type == ARG_PTR_TO_UNINIT_MEM; | |
4411 | } | |
4412 | ||
4413 | static bool arg_type_is_mem_size(enum bpf_arg_type type) | |
4414 | { | |
4415 | return type == ARG_CONST_SIZE || | |
4416 | type == ARG_CONST_SIZE_OR_ZERO; | |
4417 | } | |
4418 | ||
457f4436 AN |
4419 | static bool arg_type_is_alloc_size(enum bpf_arg_type type) |
4420 | { | |
4421 | return type == ARG_CONST_ALLOC_SIZE_OR_ZERO; | |
4422 | } | |
4423 | ||
57c3bb72 AI |
4424 | static bool arg_type_is_int_ptr(enum bpf_arg_type type) |
4425 | { | |
4426 | return type == ARG_PTR_TO_INT || | |
4427 | type == ARG_PTR_TO_LONG; | |
4428 | } | |
4429 | ||
4430 | static int int_ptr_type_to_size(enum bpf_arg_type type) | |
4431 | { | |
4432 | if (type == ARG_PTR_TO_INT) | |
4433 | return sizeof(u32); | |
4434 | else if (type == ARG_PTR_TO_LONG) | |
4435 | return sizeof(u64); | |
4436 | ||
4437 | return -EINVAL; | |
4438 | } | |
4439 | ||
912f442c LB |
4440 | static int resolve_map_arg_type(struct bpf_verifier_env *env, |
4441 | const struct bpf_call_arg_meta *meta, | |
4442 | enum bpf_arg_type *arg_type) | |
4443 | { | |
4444 | if (!meta->map_ptr) { | |
4445 | /* kernel subsystem misconfigured verifier */ | |
4446 | verbose(env, "invalid map_ptr to access map->type\n"); | |
4447 | return -EACCES; | |
4448 | } | |
4449 | ||
4450 | switch (meta->map_ptr->map_type) { | |
4451 | case BPF_MAP_TYPE_SOCKMAP: | |
4452 | case BPF_MAP_TYPE_SOCKHASH: | |
4453 | if (*arg_type == ARG_PTR_TO_MAP_VALUE) { | |
6550f2dd | 4454 | *arg_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON; |
912f442c LB |
4455 | } else { |
4456 | verbose(env, "invalid arg_type for sockmap/sockhash\n"); | |
4457 | return -EINVAL; | |
4458 | } | |
4459 | break; | |
4460 | ||
4461 | default: | |
4462 | break; | |
4463 | } | |
4464 | return 0; | |
4465 | } | |
4466 | ||
f79e7ea5 LB |
4467 | struct bpf_reg_types { |
4468 | const enum bpf_reg_type types[10]; | |
1df8f55a | 4469 | u32 *btf_id; |
f79e7ea5 LB |
4470 | }; |
4471 | ||
4472 | static const struct bpf_reg_types map_key_value_types = { | |
4473 | .types = { | |
4474 | PTR_TO_STACK, | |
4475 | PTR_TO_PACKET, | |
4476 | PTR_TO_PACKET_META, | |
4477 | PTR_TO_MAP_VALUE, | |
4478 | }, | |
4479 | }; | |
4480 | ||
4481 | static const struct bpf_reg_types sock_types = { | |
4482 | .types = { | |
4483 | PTR_TO_SOCK_COMMON, | |
4484 | PTR_TO_SOCKET, | |
4485 | PTR_TO_TCP_SOCK, | |
4486 | PTR_TO_XDP_SOCK, | |
4487 | }, | |
4488 | }; | |
4489 | ||
49a2a4d4 | 4490 | #ifdef CONFIG_NET |
1df8f55a MKL |
4491 | static const struct bpf_reg_types btf_id_sock_common_types = { |
4492 | .types = { | |
4493 | PTR_TO_SOCK_COMMON, | |
4494 | PTR_TO_SOCKET, | |
4495 | PTR_TO_TCP_SOCK, | |
4496 | PTR_TO_XDP_SOCK, | |
4497 | PTR_TO_BTF_ID, | |
4498 | }, | |
4499 | .btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], | |
4500 | }; | |
49a2a4d4 | 4501 | #endif |
1df8f55a | 4502 | |
f79e7ea5 LB |
4503 | static const struct bpf_reg_types mem_types = { |
4504 | .types = { | |
4505 | PTR_TO_STACK, | |
4506 | PTR_TO_PACKET, | |
4507 | PTR_TO_PACKET_META, | |
4508 | PTR_TO_MAP_VALUE, | |
4509 | PTR_TO_MEM, | |
4510 | PTR_TO_RDONLY_BUF, | |
4511 | PTR_TO_RDWR_BUF, | |
4512 | }, | |
4513 | }; | |
4514 | ||
4515 | static const struct bpf_reg_types int_ptr_types = { | |
4516 | .types = { | |
4517 | PTR_TO_STACK, | |
4518 | PTR_TO_PACKET, | |
4519 | PTR_TO_PACKET_META, | |
4520 | PTR_TO_MAP_VALUE, | |
4521 | }, | |
4522 | }; | |
4523 | ||
4524 | static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } }; | |
4525 | static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } }; | |
4526 | static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } }; | |
4527 | static const struct bpf_reg_types alloc_mem_types = { .types = { PTR_TO_MEM } }; | |
4528 | static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } }; | |
4529 | static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } }; | |
4530 | static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } }; | |
eaa6bcb7 | 4531 | static const struct bpf_reg_types percpu_btf_ptr_types = { .types = { PTR_TO_PERCPU_BTF_ID } }; |
f79e7ea5 | 4532 | |
0789e13b | 4533 | static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = { |
f79e7ea5 LB |
4534 | [ARG_PTR_TO_MAP_KEY] = &map_key_value_types, |
4535 | [ARG_PTR_TO_MAP_VALUE] = &map_key_value_types, | |
4536 | [ARG_PTR_TO_UNINIT_MAP_VALUE] = &map_key_value_types, | |
4537 | [ARG_PTR_TO_MAP_VALUE_OR_NULL] = &map_key_value_types, | |
4538 | [ARG_CONST_SIZE] = &scalar_types, | |
4539 | [ARG_CONST_SIZE_OR_ZERO] = &scalar_types, | |
4540 | [ARG_CONST_ALLOC_SIZE_OR_ZERO] = &scalar_types, | |
4541 | [ARG_CONST_MAP_PTR] = &const_map_ptr_types, | |
4542 | [ARG_PTR_TO_CTX] = &context_types, | |
4543 | [ARG_PTR_TO_CTX_OR_NULL] = &context_types, | |
4544 | [ARG_PTR_TO_SOCK_COMMON] = &sock_types, | |
49a2a4d4 | 4545 | #ifdef CONFIG_NET |
1df8f55a | 4546 | [ARG_PTR_TO_BTF_ID_SOCK_COMMON] = &btf_id_sock_common_types, |
49a2a4d4 | 4547 | #endif |
f79e7ea5 LB |
4548 | [ARG_PTR_TO_SOCKET] = &fullsock_types, |
4549 | [ARG_PTR_TO_SOCKET_OR_NULL] = &fullsock_types, | |
4550 | [ARG_PTR_TO_BTF_ID] = &btf_ptr_types, | |
4551 | [ARG_PTR_TO_SPIN_LOCK] = &spin_lock_types, | |
4552 | [ARG_PTR_TO_MEM] = &mem_types, | |
4553 | [ARG_PTR_TO_MEM_OR_NULL] = &mem_types, | |
4554 | [ARG_PTR_TO_UNINIT_MEM] = &mem_types, | |
4555 | [ARG_PTR_TO_ALLOC_MEM] = &alloc_mem_types, | |
4556 | [ARG_PTR_TO_ALLOC_MEM_OR_NULL] = &alloc_mem_types, | |
4557 | [ARG_PTR_TO_INT] = &int_ptr_types, | |
4558 | [ARG_PTR_TO_LONG] = &int_ptr_types, | |
eaa6bcb7 | 4559 | [ARG_PTR_TO_PERCPU_BTF_ID] = &percpu_btf_ptr_types, |
f79e7ea5 LB |
4560 | }; |
4561 | ||
4562 | static int check_reg_type(struct bpf_verifier_env *env, u32 regno, | |
a968d5e2 MKL |
4563 | enum bpf_arg_type arg_type, |
4564 | const u32 *arg_btf_id) | |
f79e7ea5 LB |
4565 | { |
4566 | struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; | |
4567 | enum bpf_reg_type expected, type = reg->type; | |
a968d5e2 | 4568 | const struct bpf_reg_types *compatible; |
f79e7ea5 LB |
4569 | int i, j; |
4570 | ||
a968d5e2 MKL |
4571 | compatible = compatible_reg_types[arg_type]; |
4572 | if (!compatible) { | |
4573 | verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type); | |
4574 | return -EFAULT; | |
4575 | } | |
4576 | ||
f79e7ea5 LB |
4577 | for (i = 0; i < ARRAY_SIZE(compatible->types); i++) { |
4578 | expected = compatible->types[i]; | |
4579 | if (expected == NOT_INIT) | |
4580 | break; | |
4581 | ||
4582 | if (type == expected) | |
a968d5e2 | 4583 | goto found; |
f79e7ea5 LB |
4584 | } |
4585 | ||
4586 | verbose(env, "R%d type=%s expected=", regno, reg_type_str[type]); | |
4587 | for (j = 0; j + 1 < i; j++) | |
4588 | verbose(env, "%s, ", reg_type_str[compatible->types[j]]); | |
4589 | verbose(env, "%s\n", reg_type_str[compatible->types[j]]); | |
4590 | return -EACCES; | |
a968d5e2 MKL |
4591 | |
4592 | found: | |
4593 | if (type == PTR_TO_BTF_ID) { | |
1df8f55a MKL |
4594 | if (!arg_btf_id) { |
4595 | if (!compatible->btf_id) { | |
4596 | verbose(env, "verifier internal error: missing arg compatible BTF ID\n"); | |
4597 | return -EFAULT; | |
4598 | } | |
4599 | arg_btf_id = compatible->btf_id; | |
4600 | } | |
4601 | ||
22dc4a0f AN |
4602 | if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off, |
4603 | btf_vmlinux, *arg_btf_id)) { | |
a968d5e2 | 4604 | verbose(env, "R%d is of type %s but %s is expected\n", |
22dc4a0f AN |
4605 | regno, kernel_type_name(reg->btf, reg->btf_id), |
4606 | kernel_type_name(btf_vmlinux, *arg_btf_id)); | |
a968d5e2 MKL |
4607 | return -EACCES; |
4608 | } | |
4609 | ||
4610 | if (!tnum_is_const(reg->var_off) || reg->var_off.value) { | |
4611 | verbose(env, "R%d is a pointer to in-kernel struct with non-zero offset\n", | |
4612 | regno); | |
4613 | return -EACCES; | |
4614 | } | |
4615 | } | |
4616 | ||
4617 | return 0; | |
f79e7ea5 LB |
4618 | } |
4619 | ||
af7ec138 YS |
4620 | static int check_func_arg(struct bpf_verifier_env *env, u32 arg, |
4621 | struct bpf_call_arg_meta *meta, | |
4622 | const struct bpf_func_proto *fn) | |
17a52670 | 4623 | { |
af7ec138 | 4624 | u32 regno = BPF_REG_1 + arg; |
638f5b90 | 4625 | struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; |
af7ec138 | 4626 | enum bpf_arg_type arg_type = fn->arg_type[arg]; |
f79e7ea5 | 4627 | enum bpf_reg_type type = reg->type; |
17a52670 AS |
4628 | int err = 0; |
4629 | ||
80f1d68c | 4630 | if (arg_type == ARG_DONTCARE) |
17a52670 AS |
4631 | return 0; |
4632 | ||
dc503a8a EC |
4633 | err = check_reg_arg(env, regno, SRC_OP); |
4634 | if (err) | |
4635 | return err; | |
17a52670 | 4636 | |
1be7f75d AS |
4637 | if (arg_type == ARG_ANYTHING) { |
4638 | if (is_pointer_value(env, regno)) { | |
61bd5218 JK |
4639 | verbose(env, "R%d leaks addr into helper function\n", |
4640 | regno); | |
1be7f75d AS |
4641 | return -EACCES; |
4642 | } | |
80f1d68c | 4643 | return 0; |
1be7f75d | 4644 | } |
80f1d68c | 4645 | |
de8f3a83 | 4646 | if (type_is_pkt_pointer(type) && |
3a0af8fd | 4647 | !may_access_direct_pkt_data(env, meta, BPF_READ)) { |
61bd5218 | 4648 | verbose(env, "helper access to the packet is not allowed\n"); |
6841de8b AS |
4649 | return -EACCES; |
4650 | } | |
4651 | ||
912f442c LB |
4652 | if (arg_type == ARG_PTR_TO_MAP_VALUE || |
4653 | arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE || | |
4654 | arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL) { | |
4655 | err = resolve_map_arg_type(env, meta, &arg_type); | |
4656 | if (err) | |
4657 | return err; | |
4658 | } | |
4659 | ||
fd1b0d60 LB |
4660 | if (register_is_null(reg) && arg_type_may_be_null(arg_type)) |
4661 | /* A NULL register has a SCALAR_VALUE type, so skip | |
4662 | * type checking. | |
4663 | */ | |
4664 | goto skip_type_check; | |
4665 | ||
a968d5e2 | 4666 | err = check_reg_type(env, regno, arg_type, fn->arg_btf_id[arg]); |
f79e7ea5 LB |
4667 | if (err) |
4668 | return err; | |
4669 | ||
a968d5e2 | 4670 | if (type == PTR_TO_CTX) { |
feec7040 LB |
4671 | err = check_ctx_reg(env, reg, regno); |
4672 | if (err < 0) | |
4673 | return err; | |
d7b9454a LB |
4674 | } |
4675 | ||
fd1b0d60 | 4676 | skip_type_check: |
02f7c958 | 4677 | if (reg->ref_obj_id) { |
457f4436 AN |
4678 | if (meta->ref_obj_id) { |
4679 | verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n", | |
4680 | regno, reg->ref_obj_id, | |
4681 | meta->ref_obj_id); | |
4682 | return -EFAULT; | |
4683 | } | |
4684 | meta->ref_obj_id = reg->ref_obj_id; | |
17a52670 AS |
4685 | } |
4686 | ||
17a52670 AS |
4687 | if (arg_type == ARG_CONST_MAP_PTR) { |
4688 | /* bpf_map_xxx(map_ptr) call: remember that map_ptr */ | |
33ff9823 | 4689 | meta->map_ptr = reg->map_ptr; |
17a52670 AS |
4690 | } else if (arg_type == ARG_PTR_TO_MAP_KEY) { |
4691 | /* bpf_map_xxx(..., map_ptr, ..., key) call: | |
4692 | * check that [key, key + map->key_size) are within | |
4693 | * stack limits and initialized | |
4694 | */ | |
33ff9823 | 4695 | if (!meta->map_ptr) { |
17a52670 AS |
4696 | /* in function declaration map_ptr must come before |
4697 | * map_key, so that it's verified and known before | |
4698 | * we have to check map_key here. Otherwise it means | |
4699 | * that kernel subsystem misconfigured verifier | |
4700 | */ | |
61bd5218 | 4701 | verbose(env, "invalid map_ptr to access map->key\n"); |
17a52670 AS |
4702 | return -EACCES; |
4703 | } | |
d71962f3 PC |
4704 | err = check_helper_mem_access(env, regno, |
4705 | meta->map_ptr->key_size, false, | |
4706 | NULL); | |
2ea864c5 | 4707 | } else if (arg_type == ARG_PTR_TO_MAP_VALUE || |
6ac99e8f MKL |
4708 | (arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL && |
4709 | !register_is_null(reg)) || | |
2ea864c5 | 4710 | arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE) { |
17a52670 AS |
4711 | /* bpf_map_xxx(..., map_ptr, ..., value) call: |
4712 | * check [value, value + map->value_size) validity | |
4713 | */ | |
33ff9823 | 4714 | if (!meta->map_ptr) { |
17a52670 | 4715 | /* kernel subsystem misconfigured verifier */ |
61bd5218 | 4716 | verbose(env, "invalid map_ptr to access map->value\n"); |
17a52670 AS |
4717 | return -EACCES; |
4718 | } | |
2ea864c5 | 4719 | meta->raw_mode = (arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE); |
d71962f3 PC |
4720 | err = check_helper_mem_access(env, regno, |
4721 | meta->map_ptr->value_size, false, | |
2ea864c5 | 4722 | meta); |
eaa6bcb7 HL |
4723 | } else if (arg_type == ARG_PTR_TO_PERCPU_BTF_ID) { |
4724 | if (!reg->btf_id) { | |
4725 | verbose(env, "Helper has invalid btf_id in R%d\n", regno); | |
4726 | return -EACCES; | |
4727 | } | |
22dc4a0f | 4728 | meta->ret_btf = reg->btf; |
eaa6bcb7 | 4729 | meta->ret_btf_id = reg->btf_id; |
c18f0b6a LB |
4730 | } else if (arg_type == ARG_PTR_TO_SPIN_LOCK) { |
4731 | if (meta->func_id == BPF_FUNC_spin_lock) { | |
4732 | if (process_spin_lock(env, regno, true)) | |
4733 | return -EACCES; | |
4734 | } else if (meta->func_id == BPF_FUNC_spin_unlock) { | |
4735 | if (process_spin_lock(env, regno, false)) | |
4736 | return -EACCES; | |
4737 | } else { | |
4738 | verbose(env, "verifier internal error\n"); | |
4739 | return -EFAULT; | |
4740 | } | |
a2bbe7cc LB |
4741 | } else if (arg_type_is_mem_ptr(arg_type)) { |
4742 | /* The access to this pointer is only checked when we hit the | |
4743 | * next is_mem_size argument below. | |
4744 | */ | |
4745 | meta->raw_mode = (arg_type == ARG_PTR_TO_UNINIT_MEM); | |
90133415 | 4746 | } else if (arg_type_is_mem_size(arg_type)) { |
39f19ebb | 4747 | bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO); |
17a52670 | 4748 | |
10060503 JF |
4749 | /* This is used to refine r0 return value bounds for helpers |
4750 | * that enforce this value as an upper bound on return values. | |
4751 | * See do_refine_retval_range() for helpers that can refine | |
4752 | * the return value. C type of helper is u32 so we pull register | |
4753 | * bound from umax_value however, if negative verifier errors | |
4754 | * out. Only upper bounds can be learned because retval is an | |
4755 | * int type and negative retvals are allowed. | |
849fa506 | 4756 | */ |
10060503 | 4757 | meta->msize_max_value = reg->umax_value; |
849fa506 | 4758 | |
f1174f77 EC |
4759 | /* The register is SCALAR_VALUE; the access check |
4760 | * happens using its boundaries. | |
06c1c049 | 4761 | */ |
f1174f77 | 4762 | if (!tnum_is_const(reg->var_off)) |
06c1c049 GB |
4763 | /* For unprivileged variable accesses, disable raw |
4764 | * mode so that the program is required to | |
4765 | * initialize all the memory that the helper could | |
4766 | * just partially fill up. | |
4767 | */ | |
4768 | meta = NULL; | |
4769 | ||
b03c9f9f | 4770 | if (reg->smin_value < 0) { |
61bd5218 | 4771 | verbose(env, "R%d min value is negative, either use unsigned or 'var &= const'\n", |
f1174f77 EC |
4772 | regno); |
4773 | return -EACCES; | |
4774 | } | |
06c1c049 | 4775 | |
b03c9f9f | 4776 | if (reg->umin_value == 0) { |
f1174f77 EC |
4777 | err = check_helper_mem_access(env, regno - 1, 0, |
4778 | zero_size_allowed, | |
4779 | meta); | |
06c1c049 GB |
4780 | if (err) |
4781 | return err; | |
06c1c049 | 4782 | } |
f1174f77 | 4783 | |
b03c9f9f | 4784 | if (reg->umax_value >= BPF_MAX_VAR_SIZ) { |
61bd5218 | 4785 | verbose(env, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n", |
f1174f77 EC |
4786 | regno); |
4787 | return -EACCES; | |
4788 | } | |
4789 | err = check_helper_mem_access(env, regno - 1, | |
b03c9f9f | 4790 | reg->umax_value, |
f1174f77 | 4791 | zero_size_allowed, meta); |
b5dc0163 AS |
4792 | if (!err) |
4793 | err = mark_chain_precision(env, regno); | |
457f4436 AN |
4794 | } else if (arg_type_is_alloc_size(arg_type)) { |
4795 | if (!tnum_is_const(reg->var_off)) { | |
28a8add6 | 4796 | verbose(env, "R%d is not a known constant'\n", |
457f4436 AN |
4797 | regno); |
4798 | return -EACCES; | |
4799 | } | |
4800 | meta->mem_size = reg->var_off.value; | |
57c3bb72 AI |
4801 | } else if (arg_type_is_int_ptr(arg_type)) { |
4802 | int size = int_ptr_type_to_size(arg_type); | |
4803 | ||
4804 | err = check_helper_mem_access(env, regno, size, false, meta); | |
4805 | if (err) | |
4806 | return err; | |
4807 | err = check_ptr_alignment(env, reg, 0, size, true); | |
17a52670 AS |
4808 | } |
4809 | ||
4810 | return err; | |
4811 | } | |
4812 | ||
0126240f LB |
4813 | static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id) |
4814 | { | |
4815 | enum bpf_attach_type eatype = env->prog->expected_attach_type; | |
7e40781c | 4816 | enum bpf_prog_type type = resolve_prog_type(env->prog); |
0126240f LB |
4817 | |
4818 | if (func_id != BPF_FUNC_map_update_elem) | |
4819 | return false; | |
4820 | ||
4821 | /* It's not possible to get access to a locked struct sock in these | |
4822 | * contexts, so updating is safe. | |
4823 | */ | |
4824 | switch (type) { | |
4825 | case BPF_PROG_TYPE_TRACING: | |
4826 | if (eatype == BPF_TRACE_ITER) | |
4827 | return true; | |
4828 | break; | |
4829 | case BPF_PROG_TYPE_SOCKET_FILTER: | |
4830 | case BPF_PROG_TYPE_SCHED_CLS: | |
4831 | case BPF_PROG_TYPE_SCHED_ACT: | |
4832 | case BPF_PROG_TYPE_XDP: | |
4833 | case BPF_PROG_TYPE_SK_REUSEPORT: | |
4834 | case BPF_PROG_TYPE_FLOW_DISSECTOR: | |
4835 | case BPF_PROG_TYPE_SK_LOOKUP: | |
4836 | return true; | |
4837 | default: | |
4838 | break; | |
4839 | } | |
4840 | ||
4841 | verbose(env, "cannot update sockmap in this context\n"); | |
4842 | return false; | |
4843 | } | |
4844 | ||
e411901c MF |
4845 | static bool allow_tail_call_in_subprogs(struct bpf_verifier_env *env) |
4846 | { | |
4847 | return env->prog->jit_requested && IS_ENABLED(CONFIG_X86_64); | |
4848 | } | |
4849 | ||
61bd5218 JK |
4850 | static int check_map_func_compatibility(struct bpf_verifier_env *env, |
4851 | struct bpf_map *map, int func_id) | |
35578d79 | 4852 | { |
35578d79 KX |
4853 | if (!map) |
4854 | return 0; | |
4855 | ||
6aff67c8 AS |
4856 | /* We need a two way check, first is from map perspective ... */ |
4857 | switch (map->map_type) { | |
4858 | case BPF_MAP_TYPE_PROG_ARRAY: | |
4859 | if (func_id != BPF_FUNC_tail_call) | |
4860 | goto error; | |
4861 | break; | |
4862 | case BPF_MAP_TYPE_PERF_EVENT_ARRAY: | |
4863 | if (func_id != BPF_FUNC_perf_event_read && | |
908432ca | 4864 | func_id != BPF_FUNC_perf_event_output && |
a7658e1a | 4865 | func_id != BPF_FUNC_skb_output && |
d831ee84 EC |
4866 | func_id != BPF_FUNC_perf_event_read_value && |
4867 | func_id != BPF_FUNC_xdp_output) | |
6aff67c8 AS |
4868 | goto error; |
4869 | break; | |
457f4436 AN |
4870 | case BPF_MAP_TYPE_RINGBUF: |
4871 | if (func_id != BPF_FUNC_ringbuf_output && | |
4872 | func_id != BPF_FUNC_ringbuf_reserve && | |
4873 | func_id != BPF_FUNC_ringbuf_submit && | |
4874 | func_id != BPF_FUNC_ringbuf_discard && | |
4875 | func_id != BPF_FUNC_ringbuf_query) | |
4876 | goto error; | |
4877 | break; | |
6aff67c8 AS |
4878 | case BPF_MAP_TYPE_STACK_TRACE: |
4879 | if (func_id != BPF_FUNC_get_stackid) | |
4880 | goto error; | |
4881 | break; | |
4ed8ec52 | 4882 | case BPF_MAP_TYPE_CGROUP_ARRAY: |
60747ef4 | 4883 | if (func_id != BPF_FUNC_skb_under_cgroup && |
60d20f91 | 4884 | func_id != BPF_FUNC_current_task_under_cgroup) |
4a482f34 MKL |
4885 | goto error; |
4886 | break; | |
cd339431 | 4887 | case BPF_MAP_TYPE_CGROUP_STORAGE: |
b741f163 | 4888 | case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE: |
cd339431 RG |
4889 | if (func_id != BPF_FUNC_get_local_storage) |
4890 | goto error; | |
4891 | break; | |
546ac1ff | 4892 | case BPF_MAP_TYPE_DEVMAP: |
6f9d451a | 4893 | case BPF_MAP_TYPE_DEVMAP_HASH: |
0cdbb4b0 THJ |
4894 | if (func_id != BPF_FUNC_redirect_map && |
4895 | func_id != BPF_FUNC_map_lookup_elem) | |
546ac1ff JF |
4896 | goto error; |
4897 | break; | |
fbfc504a BT |
4898 | /* Restrict bpf side of cpumap and xskmap, open when use-cases |
4899 | * appear. | |
4900 | */ | |
6710e112 JDB |
4901 | case BPF_MAP_TYPE_CPUMAP: |
4902 | if (func_id != BPF_FUNC_redirect_map) | |
4903 | goto error; | |
4904 | break; | |
fada7fdc JL |
4905 | case BPF_MAP_TYPE_XSKMAP: |
4906 | if (func_id != BPF_FUNC_redirect_map && | |
4907 | func_id != BPF_FUNC_map_lookup_elem) | |
4908 | goto error; | |
4909 | break; | |
56f668df | 4910 | case BPF_MAP_TYPE_ARRAY_OF_MAPS: |
bcc6b1b7 | 4911 | case BPF_MAP_TYPE_HASH_OF_MAPS: |
56f668df MKL |
4912 | if (func_id != BPF_FUNC_map_lookup_elem) |
4913 | goto error; | |
16a43625 | 4914 | break; |
174a79ff JF |
4915 | case BPF_MAP_TYPE_SOCKMAP: |
4916 | if (func_id != BPF_FUNC_sk_redirect_map && | |
4917 | func_id != BPF_FUNC_sock_map_update && | |
4f738adb | 4918 | func_id != BPF_FUNC_map_delete_elem && |
9fed9000 | 4919 | func_id != BPF_FUNC_msg_redirect_map && |
64d85290 | 4920 | func_id != BPF_FUNC_sk_select_reuseport && |
0126240f LB |
4921 | func_id != BPF_FUNC_map_lookup_elem && |
4922 | !may_update_sockmap(env, func_id)) | |
174a79ff JF |
4923 | goto error; |
4924 | break; | |
81110384 JF |
4925 | case BPF_MAP_TYPE_SOCKHASH: |
4926 | if (func_id != BPF_FUNC_sk_redirect_hash && | |
4927 | func_id != BPF_FUNC_sock_hash_update && | |
4928 | func_id != BPF_FUNC_map_delete_elem && | |
9fed9000 | 4929 | func_id != BPF_FUNC_msg_redirect_hash && |
64d85290 | 4930 | func_id != BPF_FUNC_sk_select_reuseport && |
0126240f LB |
4931 | func_id != BPF_FUNC_map_lookup_elem && |
4932 | !may_update_sockmap(env, func_id)) | |
81110384 JF |
4933 | goto error; |
4934 | break; | |
2dbb9b9e MKL |
4935 | case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY: |
4936 | if (func_id != BPF_FUNC_sk_select_reuseport) | |
4937 | goto error; | |
4938 | break; | |
f1a2e44a MV |
4939 | case BPF_MAP_TYPE_QUEUE: |
4940 | case BPF_MAP_TYPE_STACK: | |
4941 | if (func_id != BPF_FUNC_map_peek_elem && | |
4942 | func_id != BPF_FUNC_map_pop_elem && | |
4943 | func_id != BPF_FUNC_map_push_elem) | |
4944 | goto error; | |
4945 | break; | |
6ac99e8f MKL |
4946 | case BPF_MAP_TYPE_SK_STORAGE: |
4947 | if (func_id != BPF_FUNC_sk_storage_get && | |
4948 | func_id != BPF_FUNC_sk_storage_delete) | |
4949 | goto error; | |
4950 | break; | |
8ea63684 KS |
4951 | case BPF_MAP_TYPE_INODE_STORAGE: |
4952 | if (func_id != BPF_FUNC_inode_storage_get && | |
4953 | func_id != BPF_FUNC_inode_storage_delete) | |
4954 | goto error; | |
4955 | break; | |
4cf1bc1f KS |
4956 | case BPF_MAP_TYPE_TASK_STORAGE: |
4957 | if (func_id != BPF_FUNC_task_storage_get && | |
4958 | func_id != BPF_FUNC_task_storage_delete) | |
4959 | goto error; | |
4960 | break; | |
6aff67c8 AS |
4961 | default: |
4962 | break; | |
4963 | } | |
4964 | ||
4965 | /* ... and second from the function itself. */ | |
4966 | switch (func_id) { | |
4967 | case BPF_FUNC_tail_call: | |
4968 | if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) | |
4969 | goto error; | |
e411901c MF |
4970 | if (env->subprog_cnt > 1 && !allow_tail_call_in_subprogs(env)) { |
4971 | verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n"); | |
f4d7e40a AS |
4972 | return -EINVAL; |
4973 | } | |
6aff67c8 AS |
4974 | break; |
4975 | case BPF_FUNC_perf_event_read: | |
4976 | case BPF_FUNC_perf_event_output: | |
908432ca | 4977 | case BPF_FUNC_perf_event_read_value: |
a7658e1a | 4978 | case BPF_FUNC_skb_output: |
d831ee84 | 4979 | case BPF_FUNC_xdp_output: |
6aff67c8 AS |
4980 | if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) |
4981 | goto error; | |
4982 | break; | |
4983 | case BPF_FUNC_get_stackid: | |
4984 | if (map->map_type != BPF_MAP_TYPE_STACK_TRACE) | |
4985 | goto error; | |
4986 | break; | |
60d20f91 | 4987 | case BPF_FUNC_current_task_under_cgroup: |
747ea55e | 4988 | case BPF_FUNC_skb_under_cgroup: |
4a482f34 MKL |
4989 | if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY) |
4990 | goto error; | |
4991 | break; | |
97f91a7c | 4992 | case BPF_FUNC_redirect_map: |
9c270af3 | 4993 | if (map->map_type != BPF_MAP_TYPE_DEVMAP && |
6f9d451a | 4994 | map->map_type != BPF_MAP_TYPE_DEVMAP_HASH && |
fbfc504a BT |
4995 | map->map_type != BPF_MAP_TYPE_CPUMAP && |
4996 | map->map_type != BPF_MAP_TYPE_XSKMAP) | |
97f91a7c JF |
4997 | goto error; |
4998 | break; | |
174a79ff | 4999 | case BPF_FUNC_sk_redirect_map: |
4f738adb | 5000 | case BPF_FUNC_msg_redirect_map: |
81110384 | 5001 | case BPF_FUNC_sock_map_update: |
174a79ff JF |
5002 | if (map->map_type != BPF_MAP_TYPE_SOCKMAP) |
5003 | goto error; | |
5004 | break; | |
81110384 JF |
5005 | case BPF_FUNC_sk_redirect_hash: |
5006 | case BPF_FUNC_msg_redirect_hash: | |
5007 | case BPF_FUNC_sock_hash_update: | |
5008 | if (map->map_type != BPF_MAP_TYPE_SOCKHASH) | |
174a79ff JF |
5009 | goto error; |
5010 | break; | |
cd339431 | 5011 | case BPF_FUNC_get_local_storage: |
b741f163 RG |
5012 | if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE && |
5013 | map->map_type != BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) | |
cd339431 RG |
5014 | goto error; |
5015 | break; | |
2dbb9b9e | 5016 | case BPF_FUNC_sk_select_reuseport: |
9fed9000 JS |
5017 | if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY && |
5018 | map->map_type != BPF_MAP_TYPE_SOCKMAP && | |
5019 | map->map_type != BPF_MAP_TYPE_SOCKHASH) | |
2dbb9b9e MKL |
5020 | goto error; |
5021 | break; | |
f1a2e44a MV |
5022 | case BPF_FUNC_map_peek_elem: |
5023 | case BPF_FUNC_map_pop_elem: | |
5024 | case BPF_FUNC_map_push_elem: | |
5025 | if (map->map_type != BPF_MAP_TYPE_QUEUE && | |
5026 | map->map_type != BPF_MAP_TYPE_STACK) | |
5027 | goto error; | |
5028 | break; | |
6ac99e8f MKL |
5029 | case BPF_FUNC_sk_storage_get: |
5030 | case BPF_FUNC_sk_storage_delete: | |
5031 | if (map->map_type != BPF_MAP_TYPE_SK_STORAGE) | |
5032 | goto error; | |
5033 | break; | |
8ea63684 KS |
5034 | case BPF_FUNC_inode_storage_get: |
5035 | case BPF_FUNC_inode_storage_delete: | |
5036 | if (map->map_type != BPF_MAP_TYPE_INODE_STORAGE) | |
5037 | goto error; | |
5038 | break; | |
4cf1bc1f KS |
5039 | case BPF_FUNC_task_storage_get: |
5040 | case BPF_FUNC_task_storage_delete: | |
5041 | if (map->map_type != BPF_MAP_TYPE_TASK_STORAGE) | |
5042 | goto error; | |
5043 | break; | |
6aff67c8 AS |
5044 | default: |
5045 | break; | |
35578d79 KX |
5046 | } |
5047 | ||
5048 | return 0; | |
6aff67c8 | 5049 | error: |
61bd5218 | 5050 | verbose(env, "cannot pass map_type %d into func %s#%d\n", |
ebb676da | 5051 | map->map_type, func_id_name(func_id), func_id); |
6aff67c8 | 5052 | return -EINVAL; |
35578d79 KX |
5053 | } |
5054 | ||
90133415 | 5055 | static bool check_raw_mode_ok(const struct bpf_func_proto *fn) |
435faee1 DB |
5056 | { |
5057 | int count = 0; | |
5058 | ||
39f19ebb | 5059 | if (fn->arg1_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 5060 | count++; |
39f19ebb | 5061 | if (fn->arg2_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 5062 | count++; |
39f19ebb | 5063 | if (fn->arg3_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 5064 | count++; |
39f19ebb | 5065 | if (fn->arg4_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 5066 | count++; |
39f19ebb | 5067 | if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 DB |
5068 | count++; |
5069 | ||
90133415 DB |
5070 | /* We only support one arg being in raw mode at the moment, |
5071 | * which is sufficient for the helper functions we have | |
5072 | * right now. | |
5073 | */ | |
5074 | return count <= 1; | |
5075 | } | |
5076 | ||
5077 | static bool check_args_pair_invalid(enum bpf_arg_type arg_curr, | |
5078 | enum bpf_arg_type arg_next) | |
5079 | { | |
5080 | return (arg_type_is_mem_ptr(arg_curr) && | |
5081 | !arg_type_is_mem_size(arg_next)) || | |
5082 | (!arg_type_is_mem_ptr(arg_curr) && | |
5083 | arg_type_is_mem_size(arg_next)); | |
5084 | } | |
5085 | ||
5086 | static bool check_arg_pair_ok(const struct bpf_func_proto *fn) | |
5087 | { | |
5088 | /* bpf_xxx(..., buf, len) call will access 'len' | |
5089 | * bytes from memory 'buf'. Both arg types need | |
5090 | * to be paired, so make sure there's no buggy | |
5091 | * helper function specification. | |
5092 | */ | |
5093 | if (arg_type_is_mem_size(fn->arg1_type) || | |
5094 | arg_type_is_mem_ptr(fn->arg5_type) || | |
5095 | check_args_pair_invalid(fn->arg1_type, fn->arg2_type) || | |
5096 | check_args_pair_invalid(fn->arg2_type, fn->arg3_type) || | |
5097 | check_args_pair_invalid(fn->arg3_type, fn->arg4_type) || | |
5098 | check_args_pair_invalid(fn->arg4_type, fn->arg5_type)) | |
5099 | return false; | |
5100 | ||
5101 | return true; | |
5102 | } | |
5103 | ||
1b986589 | 5104 | static bool check_refcount_ok(const struct bpf_func_proto *fn, int func_id) |
fd978bf7 JS |
5105 | { |
5106 | int count = 0; | |
5107 | ||
1b986589 | 5108 | if (arg_type_may_be_refcounted(fn->arg1_type)) |
fd978bf7 | 5109 | count++; |
1b986589 | 5110 | if (arg_type_may_be_refcounted(fn->arg2_type)) |
fd978bf7 | 5111 | count++; |
1b986589 | 5112 | if (arg_type_may_be_refcounted(fn->arg3_type)) |
fd978bf7 | 5113 | count++; |
1b986589 | 5114 | if (arg_type_may_be_refcounted(fn->arg4_type)) |
fd978bf7 | 5115 | count++; |
1b986589 | 5116 | if (arg_type_may_be_refcounted(fn->arg5_type)) |
fd978bf7 JS |
5117 | count++; |
5118 | ||
1b986589 MKL |
5119 | /* A reference acquiring function cannot acquire |
5120 | * another refcounted ptr. | |
5121 | */ | |
64d85290 | 5122 | if (may_be_acquire_function(func_id) && count) |
1b986589 MKL |
5123 | return false; |
5124 | ||
fd978bf7 JS |
5125 | /* We only support one arg being unreferenced at the moment, |
5126 | * which is sufficient for the helper functions we have right now. | |
5127 | */ | |
5128 | return count <= 1; | |
5129 | } | |
5130 | ||
9436ef6e LB |
5131 | static bool check_btf_id_ok(const struct bpf_func_proto *fn) |
5132 | { | |
5133 | int i; | |
5134 | ||
1df8f55a | 5135 | for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) { |
9436ef6e LB |
5136 | if (fn->arg_type[i] == ARG_PTR_TO_BTF_ID && !fn->arg_btf_id[i]) |
5137 | return false; | |
5138 | ||
1df8f55a MKL |
5139 | if (fn->arg_type[i] != ARG_PTR_TO_BTF_ID && fn->arg_btf_id[i]) |
5140 | return false; | |
5141 | } | |
5142 | ||
9436ef6e LB |
5143 | return true; |
5144 | } | |
5145 | ||
1b986589 | 5146 | static int check_func_proto(const struct bpf_func_proto *fn, int func_id) |
90133415 DB |
5147 | { |
5148 | return check_raw_mode_ok(fn) && | |
fd978bf7 | 5149 | check_arg_pair_ok(fn) && |
9436ef6e | 5150 | check_btf_id_ok(fn) && |
1b986589 | 5151 | check_refcount_ok(fn, func_id) ? 0 : -EINVAL; |
435faee1 DB |
5152 | } |
5153 | ||
de8f3a83 DB |
5154 | /* Packet data might have moved, any old PTR_TO_PACKET[_META,_END] |
5155 | * are now invalid, so turn them into unknown SCALAR_VALUE. | |
f1174f77 | 5156 | */ |
f4d7e40a AS |
5157 | static void __clear_all_pkt_pointers(struct bpf_verifier_env *env, |
5158 | struct bpf_func_state *state) | |
969bf05e | 5159 | { |
58e2af8b | 5160 | struct bpf_reg_state *regs = state->regs, *reg; |
969bf05e AS |
5161 | int i; |
5162 | ||
5163 | for (i = 0; i < MAX_BPF_REG; i++) | |
de8f3a83 | 5164 | if (reg_is_pkt_pointer_any(®s[i])) |
61bd5218 | 5165 | mark_reg_unknown(env, regs, i); |
969bf05e | 5166 | |
f3709f69 JS |
5167 | bpf_for_each_spilled_reg(i, state, reg) { |
5168 | if (!reg) | |
969bf05e | 5169 | continue; |
de8f3a83 | 5170 | if (reg_is_pkt_pointer_any(reg)) |
f54c7898 | 5171 | __mark_reg_unknown(env, reg); |
969bf05e AS |
5172 | } |
5173 | } | |
5174 | ||
f4d7e40a AS |
5175 | static void clear_all_pkt_pointers(struct bpf_verifier_env *env) |
5176 | { | |
5177 | struct bpf_verifier_state *vstate = env->cur_state; | |
5178 | int i; | |
5179 | ||
5180 | for (i = 0; i <= vstate->curframe; i++) | |
5181 | __clear_all_pkt_pointers(env, vstate->frame[i]); | |
5182 | } | |
5183 | ||
6d94e741 AS |
5184 | enum { |
5185 | AT_PKT_END = -1, | |
5186 | BEYOND_PKT_END = -2, | |
5187 | }; | |
5188 | ||
5189 | static void mark_pkt_end(struct bpf_verifier_state *vstate, int regn, bool range_open) | |
5190 | { | |
5191 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
5192 | struct bpf_reg_state *reg = &state->regs[regn]; | |
5193 | ||
5194 | if (reg->type != PTR_TO_PACKET) | |
5195 | /* PTR_TO_PACKET_META is not supported yet */ | |
5196 | return; | |
5197 | ||
5198 | /* The 'reg' is pkt > pkt_end or pkt >= pkt_end. | |
5199 | * How far beyond pkt_end it goes is unknown. | |
5200 | * if (!range_open) it's the case of pkt >= pkt_end | |
5201 | * if (range_open) it's the case of pkt > pkt_end | |
5202 | * hence this pointer is at least 1 byte bigger than pkt_end | |
5203 | */ | |
5204 | if (range_open) | |
5205 | reg->range = BEYOND_PKT_END; | |
5206 | else | |
5207 | reg->range = AT_PKT_END; | |
5208 | } | |
5209 | ||
fd978bf7 | 5210 | static void release_reg_references(struct bpf_verifier_env *env, |
1b986589 MKL |
5211 | struct bpf_func_state *state, |
5212 | int ref_obj_id) | |
fd978bf7 JS |
5213 | { |
5214 | struct bpf_reg_state *regs = state->regs, *reg; | |
5215 | int i; | |
5216 | ||
5217 | for (i = 0; i < MAX_BPF_REG; i++) | |
1b986589 | 5218 | if (regs[i].ref_obj_id == ref_obj_id) |
fd978bf7 JS |
5219 | mark_reg_unknown(env, regs, i); |
5220 | ||
5221 | bpf_for_each_spilled_reg(i, state, reg) { | |
5222 | if (!reg) | |
5223 | continue; | |
1b986589 | 5224 | if (reg->ref_obj_id == ref_obj_id) |
f54c7898 | 5225 | __mark_reg_unknown(env, reg); |
fd978bf7 JS |
5226 | } |
5227 | } | |
5228 | ||
5229 | /* The pointer with the specified id has released its reference to kernel | |
5230 | * resources. Identify all copies of the same pointer and clear the reference. | |
5231 | */ | |
5232 | static int release_reference(struct bpf_verifier_env *env, | |
1b986589 | 5233 | int ref_obj_id) |
fd978bf7 JS |
5234 | { |
5235 | struct bpf_verifier_state *vstate = env->cur_state; | |
1b986589 | 5236 | int err; |
fd978bf7 JS |
5237 | int i; |
5238 | ||
1b986589 MKL |
5239 | err = release_reference_state(cur_func(env), ref_obj_id); |
5240 | if (err) | |
5241 | return err; | |
5242 | ||
fd978bf7 | 5243 | for (i = 0; i <= vstate->curframe; i++) |
1b986589 | 5244 | release_reg_references(env, vstate->frame[i], ref_obj_id); |
fd978bf7 | 5245 | |
1b986589 | 5246 | return 0; |
fd978bf7 JS |
5247 | } |
5248 | ||
51c39bb1 AS |
5249 | static void clear_caller_saved_regs(struct bpf_verifier_env *env, |
5250 | struct bpf_reg_state *regs) | |
5251 | { | |
5252 | int i; | |
5253 | ||
5254 | /* after the call registers r0 - r5 were scratched */ | |
5255 | for (i = 0; i < CALLER_SAVED_REGS; i++) { | |
5256 | mark_reg_not_init(env, regs, caller_saved[i]); | |
5257 | check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK); | |
5258 | } | |
5259 | } | |
5260 | ||
f4d7e40a AS |
5261 | static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, |
5262 | int *insn_idx) | |
5263 | { | |
5264 | struct bpf_verifier_state *state = env->cur_state; | |
51c39bb1 | 5265 | struct bpf_func_info_aux *func_info_aux; |
f4d7e40a | 5266 | struct bpf_func_state *caller, *callee; |
fd978bf7 | 5267 | int i, err, subprog, target_insn; |
51c39bb1 | 5268 | bool is_global = false; |
f4d7e40a | 5269 | |
aada9ce6 | 5270 | if (state->curframe + 1 >= MAX_CALL_FRAMES) { |
f4d7e40a | 5271 | verbose(env, "the call stack of %d frames is too deep\n", |
aada9ce6 | 5272 | state->curframe + 2); |
f4d7e40a AS |
5273 | return -E2BIG; |
5274 | } | |
5275 | ||
5276 | target_insn = *insn_idx + insn->imm; | |
5277 | subprog = find_subprog(env, target_insn + 1); | |
5278 | if (subprog < 0) { | |
5279 | verbose(env, "verifier bug. No program starts at insn %d\n", | |
5280 | target_insn + 1); | |
5281 | return -EFAULT; | |
5282 | } | |
5283 | ||
5284 | caller = state->frame[state->curframe]; | |
5285 | if (state->frame[state->curframe + 1]) { | |
5286 | verbose(env, "verifier bug. Frame %d already allocated\n", | |
5287 | state->curframe + 1); | |
5288 | return -EFAULT; | |
5289 | } | |
5290 | ||
51c39bb1 AS |
5291 | func_info_aux = env->prog->aux->func_info_aux; |
5292 | if (func_info_aux) | |
5293 | is_global = func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL; | |
5294 | err = btf_check_func_arg_match(env, subprog, caller->regs); | |
5295 | if (err == -EFAULT) | |
5296 | return err; | |
5297 | if (is_global) { | |
5298 | if (err) { | |
5299 | verbose(env, "Caller passes invalid args into func#%d\n", | |
5300 | subprog); | |
5301 | return err; | |
5302 | } else { | |
5303 | if (env->log.level & BPF_LOG_LEVEL) | |
5304 | verbose(env, | |
5305 | "Func#%d is global and valid. Skipping.\n", | |
5306 | subprog); | |
5307 | clear_caller_saved_regs(env, caller->regs); | |
5308 | ||
45159b27 | 5309 | /* All global functions return a 64-bit SCALAR_VALUE */ |
51c39bb1 | 5310 | mark_reg_unknown(env, caller->regs, BPF_REG_0); |
45159b27 | 5311 | caller->regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG; |
51c39bb1 AS |
5312 | |
5313 | /* continue with next insn after call */ | |
5314 | return 0; | |
5315 | } | |
5316 | } | |
5317 | ||
f4d7e40a AS |
5318 | callee = kzalloc(sizeof(*callee), GFP_KERNEL); |
5319 | if (!callee) | |
5320 | return -ENOMEM; | |
5321 | state->frame[state->curframe + 1] = callee; | |
5322 | ||
5323 | /* callee cannot access r0, r6 - r9 for reading and has to write | |
5324 | * into its own stack before reading from it. | |
5325 | * callee can read/write into caller's stack | |
5326 | */ | |
5327 | init_func_state(env, callee, | |
5328 | /* remember the callsite, it will be used by bpf_exit */ | |
5329 | *insn_idx /* callsite */, | |
5330 | state->curframe + 1 /* frameno within this callchain */, | |
f910cefa | 5331 | subprog /* subprog number within this prog */); |
f4d7e40a | 5332 | |
fd978bf7 JS |
5333 | /* Transfer references to the callee */ |
5334 | err = transfer_reference_state(callee, caller); | |
5335 | if (err) | |
5336 | return err; | |
5337 | ||
679c782d EC |
5338 | /* copy r1 - r5 args that callee can access. The copy includes parent |
5339 | * pointers, which connects us up to the liveness chain | |
5340 | */ | |
f4d7e40a AS |
5341 | for (i = BPF_REG_1; i <= BPF_REG_5; i++) |
5342 | callee->regs[i] = caller->regs[i]; | |
5343 | ||
51c39bb1 | 5344 | clear_caller_saved_regs(env, caller->regs); |
f4d7e40a AS |
5345 | |
5346 | /* only increment it after check_reg_arg() finished */ | |
5347 | state->curframe++; | |
5348 | ||
5349 | /* and go analyze first insn of the callee */ | |
5350 | *insn_idx = target_insn; | |
5351 | ||
06ee7115 | 5352 | if (env->log.level & BPF_LOG_LEVEL) { |
f4d7e40a AS |
5353 | verbose(env, "caller:\n"); |
5354 | print_verifier_state(env, caller); | |
5355 | verbose(env, "callee:\n"); | |
5356 | print_verifier_state(env, callee); | |
5357 | } | |
5358 | return 0; | |
5359 | } | |
5360 | ||
5361 | static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) | |
5362 | { | |
5363 | struct bpf_verifier_state *state = env->cur_state; | |
5364 | struct bpf_func_state *caller, *callee; | |
5365 | struct bpf_reg_state *r0; | |
fd978bf7 | 5366 | int err; |
f4d7e40a AS |
5367 | |
5368 | callee = state->frame[state->curframe]; | |
5369 | r0 = &callee->regs[BPF_REG_0]; | |
5370 | if (r0->type == PTR_TO_STACK) { | |
5371 | /* technically it's ok to return caller's stack pointer | |
5372 | * (or caller's caller's pointer) back to the caller, | |
5373 | * since these pointers are valid. Only current stack | |
5374 | * pointer will be invalid as soon as function exits, | |
5375 | * but let's be conservative | |
5376 | */ | |
5377 | verbose(env, "cannot return stack pointer to the caller\n"); | |
5378 | return -EINVAL; | |
5379 | } | |
5380 | ||
5381 | state->curframe--; | |
5382 | caller = state->frame[state->curframe]; | |
5383 | /* return to the caller whatever r0 had in the callee */ | |
5384 | caller->regs[BPF_REG_0] = *r0; | |
5385 | ||
fd978bf7 JS |
5386 | /* Transfer references to the caller */ |
5387 | err = transfer_reference_state(caller, callee); | |
5388 | if (err) | |
5389 | return err; | |
5390 | ||
f4d7e40a | 5391 | *insn_idx = callee->callsite + 1; |
06ee7115 | 5392 | if (env->log.level & BPF_LOG_LEVEL) { |
f4d7e40a AS |
5393 | verbose(env, "returning from callee:\n"); |
5394 | print_verifier_state(env, callee); | |
5395 | verbose(env, "to caller at %d:\n", *insn_idx); | |
5396 | print_verifier_state(env, caller); | |
5397 | } | |
5398 | /* clear everything in the callee */ | |
5399 | free_func_state(callee); | |
5400 | state->frame[state->curframe + 1] = NULL; | |
5401 | return 0; | |
5402 | } | |
5403 | ||
849fa506 YS |
5404 | static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type, |
5405 | int func_id, | |
5406 | struct bpf_call_arg_meta *meta) | |
5407 | { | |
5408 | struct bpf_reg_state *ret_reg = ®s[BPF_REG_0]; | |
5409 | ||
5410 | if (ret_type != RET_INTEGER || | |
5411 | (func_id != BPF_FUNC_get_stack && | |
47cc0ed5 DB |
5412 | func_id != BPF_FUNC_probe_read_str && |
5413 | func_id != BPF_FUNC_probe_read_kernel_str && | |
5414 | func_id != BPF_FUNC_probe_read_user_str)) | |
849fa506 YS |
5415 | return; |
5416 | ||
10060503 | 5417 | ret_reg->smax_value = meta->msize_max_value; |
fa123ac0 | 5418 | ret_reg->s32_max_value = meta->msize_max_value; |
b0270958 AS |
5419 | ret_reg->smin_value = -MAX_ERRNO; |
5420 | ret_reg->s32_min_value = -MAX_ERRNO; | |
849fa506 YS |
5421 | __reg_deduce_bounds(ret_reg); |
5422 | __reg_bound_offset(ret_reg); | |
10060503 | 5423 | __update_reg_bounds(ret_reg); |
849fa506 YS |
5424 | } |
5425 | ||
c93552c4 DB |
5426 | static int |
5427 | record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, | |
5428 | int func_id, int insn_idx) | |
5429 | { | |
5430 | struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx]; | |
591fe988 | 5431 | struct bpf_map *map = meta->map_ptr; |
c93552c4 DB |
5432 | |
5433 | if (func_id != BPF_FUNC_tail_call && | |
09772d92 DB |
5434 | func_id != BPF_FUNC_map_lookup_elem && |
5435 | func_id != BPF_FUNC_map_update_elem && | |
f1a2e44a MV |
5436 | func_id != BPF_FUNC_map_delete_elem && |
5437 | func_id != BPF_FUNC_map_push_elem && | |
5438 | func_id != BPF_FUNC_map_pop_elem && | |
5439 | func_id != BPF_FUNC_map_peek_elem) | |
c93552c4 | 5440 | return 0; |
09772d92 | 5441 | |
591fe988 | 5442 | if (map == NULL) { |
c93552c4 DB |
5443 | verbose(env, "kernel subsystem misconfigured verifier\n"); |
5444 | return -EINVAL; | |
5445 | } | |
5446 | ||
591fe988 DB |
5447 | /* In case of read-only, some additional restrictions |
5448 | * need to be applied in order to prevent altering the | |
5449 | * state of the map from program side. | |
5450 | */ | |
5451 | if ((map->map_flags & BPF_F_RDONLY_PROG) && | |
5452 | (func_id == BPF_FUNC_map_delete_elem || | |
5453 | func_id == BPF_FUNC_map_update_elem || | |
5454 | func_id == BPF_FUNC_map_push_elem || | |
5455 | func_id == BPF_FUNC_map_pop_elem)) { | |
5456 | verbose(env, "write into map forbidden\n"); | |
5457 | return -EACCES; | |
5458 | } | |
5459 | ||
d2e4c1e6 | 5460 | if (!BPF_MAP_PTR(aux->map_ptr_state)) |
c93552c4 | 5461 | bpf_map_ptr_store(aux, meta->map_ptr, |
2c78ee89 | 5462 | !meta->map_ptr->bypass_spec_v1); |
d2e4c1e6 | 5463 | else if (BPF_MAP_PTR(aux->map_ptr_state) != meta->map_ptr) |
c93552c4 | 5464 | bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON, |
2c78ee89 | 5465 | !meta->map_ptr->bypass_spec_v1); |
c93552c4 DB |
5466 | return 0; |
5467 | } | |
5468 | ||
d2e4c1e6 DB |
5469 | static int |
5470 | record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, | |
5471 | int func_id, int insn_idx) | |
5472 | { | |
5473 | struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx]; | |
5474 | struct bpf_reg_state *regs = cur_regs(env), *reg; | |
5475 | struct bpf_map *map = meta->map_ptr; | |
5476 | struct tnum range; | |
5477 | u64 val; | |
cc52d914 | 5478 | int err; |
d2e4c1e6 DB |
5479 | |
5480 | if (func_id != BPF_FUNC_tail_call) | |
5481 | return 0; | |
5482 | if (!map || map->map_type != BPF_MAP_TYPE_PROG_ARRAY) { | |
5483 | verbose(env, "kernel subsystem misconfigured verifier\n"); | |
5484 | return -EINVAL; | |
5485 | } | |
5486 | ||
5487 | range = tnum_range(0, map->max_entries - 1); | |
5488 | reg = ®s[BPF_REG_3]; | |
5489 | ||
5490 | if (!register_is_const(reg) || !tnum_in(range, reg->var_off)) { | |
5491 | bpf_map_key_store(aux, BPF_MAP_KEY_POISON); | |
5492 | return 0; | |
5493 | } | |
5494 | ||
cc52d914 DB |
5495 | err = mark_chain_precision(env, BPF_REG_3); |
5496 | if (err) | |
5497 | return err; | |
5498 | ||
d2e4c1e6 DB |
5499 | val = reg->var_off.value; |
5500 | if (bpf_map_key_unseen(aux)) | |
5501 | bpf_map_key_store(aux, val); | |
5502 | else if (!bpf_map_key_poisoned(aux) && | |
5503 | bpf_map_key_immediate(aux) != val) | |
5504 | bpf_map_key_store(aux, BPF_MAP_KEY_POISON); | |
5505 | return 0; | |
5506 | } | |
5507 | ||
fd978bf7 JS |
5508 | static int check_reference_leak(struct bpf_verifier_env *env) |
5509 | { | |
5510 | struct bpf_func_state *state = cur_func(env); | |
5511 | int i; | |
5512 | ||
5513 | for (i = 0; i < state->acquired_refs; i++) { | |
5514 | verbose(env, "Unreleased reference id=%d alloc_insn=%d\n", | |
5515 | state->refs[i].id, state->refs[i].insn_idx); | |
5516 | } | |
5517 | return state->acquired_refs ? -EINVAL : 0; | |
5518 | } | |
5519 | ||
f4d7e40a | 5520 | static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn_idx) |
17a52670 | 5521 | { |
17a52670 | 5522 | const struct bpf_func_proto *fn = NULL; |
638f5b90 | 5523 | struct bpf_reg_state *regs; |
33ff9823 | 5524 | struct bpf_call_arg_meta meta; |
969bf05e | 5525 | bool changes_data; |
17a52670 AS |
5526 | int i, err; |
5527 | ||
5528 | /* find function prototype */ | |
5529 | if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) { | |
61bd5218 JK |
5530 | verbose(env, "invalid func %s#%d\n", func_id_name(func_id), |
5531 | func_id); | |
17a52670 AS |
5532 | return -EINVAL; |
5533 | } | |
5534 | ||
00176a34 | 5535 | if (env->ops->get_func_proto) |
5e43f899 | 5536 | fn = env->ops->get_func_proto(func_id, env->prog); |
17a52670 | 5537 | if (!fn) { |
61bd5218 JK |
5538 | verbose(env, "unknown func %s#%d\n", func_id_name(func_id), |
5539 | func_id); | |
17a52670 AS |
5540 | return -EINVAL; |
5541 | } | |
5542 | ||
5543 | /* eBPF programs must be GPL compatible to use GPL-ed functions */ | |
24701ece | 5544 | if (!env->prog->gpl_compatible && fn->gpl_only) { |
3fe2867c | 5545 | verbose(env, "cannot call GPL-restricted function from non-GPL compatible program\n"); |
17a52670 AS |
5546 | return -EINVAL; |
5547 | } | |
5548 | ||
eae2e83e JO |
5549 | if (fn->allowed && !fn->allowed(env->prog)) { |
5550 | verbose(env, "helper call is not allowed in probe\n"); | |
5551 | return -EINVAL; | |
5552 | } | |
5553 | ||
04514d13 | 5554 | /* With LD_ABS/IND some JITs save/restore skb from r1. */ |
17bedab2 | 5555 | changes_data = bpf_helper_changes_pkt_data(fn->func); |
04514d13 DB |
5556 | if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) { |
5557 | verbose(env, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n", | |
5558 | func_id_name(func_id), func_id); | |
5559 | return -EINVAL; | |
5560 | } | |
969bf05e | 5561 | |
33ff9823 | 5562 | memset(&meta, 0, sizeof(meta)); |
36bbef52 | 5563 | meta.pkt_access = fn->pkt_access; |
33ff9823 | 5564 | |
1b986589 | 5565 | err = check_func_proto(fn, func_id); |
435faee1 | 5566 | if (err) { |
61bd5218 | 5567 | verbose(env, "kernel subsystem misconfigured func %s#%d\n", |
ebb676da | 5568 | func_id_name(func_id), func_id); |
435faee1 DB |
5569 | return err; |
5570 | } | |
5571 | ||
d83525ca | 5572 | meta.func_id = func_id; |
17a52670 | 5573 | /* check args */ |
a7658e1a | 5574 | for (i = 0; i < 5; i++) { |
af7ec138 | 5575 | err = check_func_arg(env, i, &meta, fn); |
a7658e1a AS |
5576 | if (err) |
5577 | return err; | |
5578 | } | |
17a52670 | 5579 | |
c93552c4 DB |
5580 | err = record_func_map(env, &meta, func_id, insn_idx); |
5581 | if (err) | |
5582 | return err; | |
5583 | ||
d2e4c1e6 DB |
5584 | err = record_func_key(env, &meta, func_id, insn_idx); |
5585 | if (err) | |
5586 | return err; | |
5587 | ||
435faee1 DB |
5588 | /* Mark slots with STACK_MISC in case of raw mode, stack offset |
5589 | * is inferred from register state. | |
5590 | */ | |
5591 | for (i = 0; i < meta.access_size; i++) { | |
ca369602 DB |
5592 | err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B, |
5593 | BPF_WRITE, -1, false); | |
435faee1 DB |
5594 | if (err) |
5595 | return err; | |
5596 | } | |
5597 | ||
fd978bf7 JS |
5598 | if (func_id == BPF_FUNC_tail_call) { |
5599 | err = check_reference_leak(env); | |
5600 | if (err) { | |
5601 | verbose(env, "tail_call would lead to reference leak\n"); | |
5602 | return err; | |
5603 | } | |
5604 | } else if (is_release_function(func_id)) { | |
1b986589 | 5605 | err = release_reference(env, meta.ref_obj_id); |
46f8bc92 MKL |
5606 | if (err) { |
5607 | verbose(env, "func %s#%d reference has not been acquired before\n", | |
5608 | func_id_name(func_id), func_id); | |
fd978bf7 | 5609 | return err; |
46f8bc92 | 5610 | } |
fd978bf7 JS |
5611 | } |
5612 | ||
638f5b90 | 5613 | regs = cur_regs(env); |
cd339431 RG |
5614 | |
5615 | /* check that flags argument in get_local_storage(map, flags) is 0, | |
5616 | * this is required because get_local_storage() can't return an error. | |
5617 | */ | |
5618 | if (func_id == BPF_FUNC_get_local_storage && | |
5619 | !register_is_null(®s[BPF_REG_2])) { | |
5620 | verbose(env, "get_local_storage() doesn't support non-zero flags\n"); | |
5621 | return -EINVAL; | |
5622 | } | |
5623 | ||
17a52670 | 5624 | /* reset caller saved regs */ |
dc503a8a | 5625 | for (i = 0; i < CALLER_SAVED_REGS; i++) { |
61bd5218 | 5626 | mark_reg_not_init(env, regs, caller_saved[i]); |
dc503a8a EC |
5627 | check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK); |
5628 | } | |
17a52670 | 5629 | |
5327ed3d JW |
5630 | /* helper call returns 64-bit value. */ |
5631 | regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG; | |
5632 | ||
dc503a8a | 5633 | /* update return register (already marked as written above) */ |
17a52670 | 5634 | if (fn->ret_type == RET_INTEGER) { |
f1174f77 | 5635 | /* sets type to SCALAR_VALUE */ |
61bd5218 | 5636 | mark_reg_unknown(env, regs, BPF_REG_0); |
17a52670 AS |
5637 | } else if (fn->ret_type == RET_VOID) { |
5638 | regs[BPF_REG_0].type = NOT_INIT; | |
3e6a4b3e RG |
5639 | } else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL || |
5640 | fn->ret_type == RET_PTR_TO_MAP_VALUE) { | |
f1174f77 | 5641 | /* There is no offset yet applied, variable or fixed */ |
61bd5218 | 5642 | mark_reg_known_zero(env, regs, BPF_REG_0); |
17a52670 AS |
5643 | /* remember map_ptr, so that check_map_access() |
5644 | * can check 'value_size' boundary of memory access | |
5645 | * to map element returned from bpf_map_lookup_elem() | |
5646 | */ | |
33ff9823 | 5647 | if (meta.map_ptr == NULL) { |
61bd5218 JK |
5648 | verbose(env, |
5649 | "kernel subsystem misconfigured verifier\n"); | |
17a52670 AS |
5650 | return -EINVAL; |
5651 | } | |
33ff9823 | 5652 | regs[BPF_REG_0].map_ptr = meta.map_ptr; |
4d31f301 DB |
5653 | if (fn->ret_type == RET_PTR_TO_MAP_VALUE) { |
5654 | regs[BPF_REG_0].type = PTR_TO_MAP_VALUE; | |
e16d2f1a AS |
5655 | if (map_value_has_spin_lock(meta.map_ptr)) |
5656 | regs[BPF_REG_0].id = ++env->id_gen; | |
4d31f301 DB |
5657 | } else { |
5658 | regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL; | |
4d31f301 | 5659 | } |
c64b7983 JS |
5660 | } else if (fn->ret_type == RET_PTR_TO_SOCKET_OR_NULL) { |
5661 | mark_reg_known_zero(env, regs, BPF_REG_0); | |
5662 | regs[BPF_REG_0].type = PTR_TO_SOCKET_OR_NULL; | |
85a51f8c LB |
5663 | } else if (fn->ret_type == RET_PTR_TO_SOCK_COMMON_OR_NULL) { |
5664 | mark_reg_known_zero(env, regs, BPF_REG_0); | |
5665 | regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON_OR_NULL; | |
655a51e5 MKL |
5666 | } else if (fn->ret_type == RET_PTR_TO_TCP_SOCK_OR_NULL) { |
5667 | mark_reg_known_zero(env, regs, BPF_REG_0); | |
5668 | regs[BPF_REG_0].type = PTR_TO_TCP_SOCK_OR_NULL; | |
457f4436 AN |
5669 | } else if (fn->ret_type == RET_PTR_TO_ALLOC_MEM_OR_NULL) { |
5670 | mark_reg_known_zero(env, regs, BPF_REG_0); | |
5671 | regs[BPF_REG_0].type = PTR_TO_MEM_OR_NULL; | |
457f4436 | 5672 | regs[BPF_REG_0].mem_size = meta.mem_size; |
63d9b80d HL |
5673 | } else if (fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID_OR_NULL || |
5674 | fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID) { | |
eaa6bcb7 HL |
5675 | const struct btf_type *t; |
5676 | ||
5677 | mark_reg_known_zero(env, regs, BPF_REG_0); | |
22dc4a0f | 5678 | t = btf_type_skip_modifiers(meta.ret_btf, meta.ret_btf_id, NULL); |
eaa6bcb7 HL |
5679 | if (!btf_type_is_struct(t)) { |
5680 | u32 tsize; | |
5681 | const struct btf_type *ret; | |
5682 | const char *tname; | |
5683 | ||
5684 | /* resolve the type size of ksym. */ | |
22dc4a0f | 5685 | ret = btf_resolve_size(meta.ret_btf, t, &tsize); |
eaa6bcb7 | 5686 | if (IS_ERR(ret)) { |
22dc4a0f | 5687 | tname = btf_name_by_offset(meta.ret_btf, t->name_off); |
eaa6bcb7 HL |
5688 | verbose(env, "unable to resolve the size of type '%s': %ld\n", |
5689 | tname, PTR_ERR(ret)); | |
5690 | return -EINVAL; | |
5691 | } | |
63d9b80d HL |
5692 | regs[BPF_REG_0].type = |
5693 | fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID ? | |
5694 | PTR_TO_MEM : PTR_TO_MEM_OR_NULL; | |
eaa6bcb7 HL |
5695 | regs[BPF_REG_0].mem_size = tsize; |
5696 | } else { | |
63d9b80d HL |
5697 | regs[BPF_REG_0].type = |
5698 | fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID ? | |
5699 | PTR_TO_BTF_ID : PTR_TO_BTF_ID_OR_NULL; | |
22dc4a0f | 5700 | regs[BPF_REG_0].btf = meta.ret_btf; |
eaa6bcb7 HL |
5701 | regs[BPF_REG_0].btf_id = meta.ret_btf_id; |
5702 | } | |
3ca1032a KS |
5703 | } else if (fn->ret_type == RET_PTR_TO_BTF_ID_OR_NULL || |
5704 | fn->ret_type == RET_PTR_TO_BTF_ID) { | |
af7ec138 YS |
5705 | int ret_btf_id; |
5706 | ||
5707 | mark_reg_known_zero(env, regs, BPF_REG_0); | |
3ca1032a KS |
5708 | regs[BPF_REG_0].type = fn->ret_type == RET_PTR_TO_BTF_ID ? |
5709 | PTR_TO_BTF_ID : | |
5710 | PTR_TO_BTF_ID_OR_NULL; | |
af7ec138 YS |
5711 | ret_btf_id = *fn->ret_btf_id; |
5712 | if (ret_btf_id == 0) { | |
5713 | verbose(env, "invalid return type %d of func %s#%d\n", | |
5714 | fn->ret_type, func_id_name(func_id), func_id); | |
5715 | return -EINVAL; | |
5716 | } | |
22dc4a0f AN |
5717 | /* current BPF helper definitions are only coming from |
5718 | * built-in code with type IDs from vmlinux BTF | |
5719 | */ | |
5720 | regs[BPF_REG_0].btf = btf_vmlinux; | |
af7ec138 | 5721 | regs[BPF_REG_0].btf_id = ret_btf_id; |
17a52670 | 5722 | } else { |
61bd5218 | 5723 | verbose(env, "unknown return type %d of func %s#%d\n", |
ebb676da | 5724 | fn->ret_type, func_id_name(func_id), func_id); |
17a52670 AS |
5725 | return -EINVAL; |
5726 | } | |
04fd61ab | 5727 | |
93c230e3 MKL |
5728 | if (reg_type_may_be_null(regs[BPF_REG_0].type)) |
5729 | regs[BPF_REG_0].id = ++env->id_gen; | |
5730 | ||
0f3adc28 | 5731 | if (is_ptr_cast_function(func_id)) { |
1b986589 MKL |
5732 | /* For release_reference() */ |
5733 | regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id; | |
64d85290 | 5734 | } else if (is_acquire_function(func_id, meta.map_ptr)) { |
0f3adc28 LB |
5735 | int id = acquire_reference_state(env, insn_idx); |
5736 | ||
5737 | if (id < 0) | |
5738 | return id; | |
5739 | /* For mark_ptr_or_null_reg() */ | |
5740 | regs[BPF_REG_0].id = id; | |
5741 | /* For release_reference() */ | |
5742 | regs[BPF_REG_0].ref_obj_id = id; | |
5743 | } | |
1b986589 | 5744 | |
849fa506 YS |
5745 | do_refine_retval_range(regs, fn->ret_type, func_id, &meta); |
5746 | ||
61bd5218 | 5747 | err = check_map_func_compatibility(env, meta.map_ptr, func_id); |
35578d79 KX |
5748 | if (err) |
5749 | return err; | |
04fd61ab | 5750 | |
fa28dcb8 SL |
5751 | if ((func_id == BPF_FUNC_get_stack || |
5752 | func_id == BPF_FUNC_get_task_stack) && | |
5753 | !env->prog->has_callchain_buf) { | |
c195651e YS |
5754 | const char *err_str; |
5755 | ||
5756 | #ifdef CONFIG_PERF_EVENTS | |
5757 | err = get_callchain_buffers(sysctl_perf_event_max_stack); | |
5758 | err_str = "cannot get callchain buffer for func %s#%d\n"; | |
5759 | #else | |
5760 | err = -ENOTSUPP; | |
5761 | err_str = "func %s#%d not supported without CONFIG_PERF_EVENTS\n"; | |
5762 | #endif | |
5763 | if (err) { | |
5764 | verbose(env, err_str, func_id_name(func_id), func_id); | |
5765 | return err; | |
5766 | } | |
5767 | ||
5768 | env->prog->has_callchain_buf = true; | |
5769 | } | |
5770 | ||
5d99cb2c SL |
5771 | if (func_id == BPF_FUNC_get_stackid || func_id == BPF_FUNC_get_stack) |
5772 | env->prog->call_get_stack = true; | |
5773 | ||
969bf05e AS |
5774 | if (changes_data) |
5775 | clear_all_pkt_pointers(env); | |
5776 | return 0; | |
5777 | } | |
5778 | ||
b03c9f9f EC |
5779 | static bool signed_add_overflows(s64 a, s64 b) |
5780 | { | |
5781 | /* Do the add in u64, where overflow is well-defined */ | |
5782 | s64 res = (s64)((u64)a + (u64)b); | |
5783 | ||
5784 | if (b < 0) | |
5785 | return res > a; | |
5786 | return res < a; | |
5787 | } | |
5788 | ||
bc895e8b | 5789 | static bool signed_add32_overflows(s32 a, s32 b) |
3f50f132 JF |
5790 | { |
5791 | /* Do the add in u32, where overflow is well-defined */ | |
5792 | s32 res = (s32)((u32)a + (u32)b); | |
5793 | ||
5794 | if (b < 0) | |
5795 | return res > a; | |
5796 | return res < a; | |
5797 | } | |
5798 | ||
bc895e8b | 5799 | static bool signed_sub_overflows(s64 a, s64 b) |
b03c9f9f EC |
5800 | { |
5801 | /* Do the sub in u64, where overflow is well-defined */ | |
5802 | s64 res = (s64)((u64)a - (u64)b); | |
5803 | ||
5804 | if (b < 0) | |
5805 | return res < a; | |
5806 | return res > a; | |
969bf05e AS |
5807 | } |
5808 | ||
3f50f132 JF |
5809 | static bool signed_sub32_overflows(s32 a, s32 b) |
5810 | { | |
bc895e8b | 5811 | /* Do the sub in u32, where overflow is well-defined */ |
3f50f132 JF |
5812 | s32 res = (s32)((u32)a - (u32)b); |
5813 | ||
5814 | if (b < 0) | |
5815 | return res < a; | |
5816 | return res > a; | |
5817 | } | |
5818 | ||
bb7f0f98 AS |
5819 | static bool check_reg_sane_offset(struct bpf_verifier_env *env, |
5820 | const struct bpf_reg_state *reg, | |
5821 | enum bpf_reg_type type) | |
5822 | { | |
5823 | bool known = tnum_is_const(reg->var_off); | |
5824 | s64 val = reg->var_off.value; | |
5825 | s64 smin = reg->smin_value; | |
5826 | ||
5827 | if (known && (val >= BPF_MAX_VAR_OFF || val <= -BPF_MAX_VAR_OFF)) { | |
5828 | verbose(env, "math between %s pointer and %lld is not allowed\n", | |
5829 | reg_type_str[type], val); | |
5830 | return false; | |
5831 | } | |
5832 | ||
5833 | if (reg->off >= BPF_MAX_VAR_OFF || reg->off <= -BPF_MAX_VAR_OFF) { | |
5834 | verbose(env, "%s pointer offset %d is not allowed\n", | |
5835 | reg_type_str[type], reg->off); | |
5836 | return false; | |
5837 | } | |
5838 | ||
5839 | if (smin == S64_MIN) { | |
5840 | verbose(env, "math between %s pointer and register with unbounded min value is not allowed\n", | |
5841 | reg_type_str[type]); | |
5842 | return false; | |
5843 | } | |
5844 | ||
5845 | if (smin >= BPF_MAX_VAR_OFF || smin <= -BPF_MAX_VAR_OFF) { | |
5846 | verbose(env, "value %lld makes %s pointer be out of bounds\n", | |
5847 | smin, reg_type_str[type]); | |
5848 | return false; | |
5849 | } | |
5850 | ||
5851 | return true; | |
5852 | } | |
5853 | ||
979d63d5 DB |
5854 | static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env) |
5855 | { | |
5856 | return &env->insn_aux_data[env->insn_idx]; | |
5857 | } | |
5858 | ||
5859 | static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, | |
5860 | u32 *ptr_limit, u8 opcode, bool off_is_neg) | |
5861 | { | |
5862 | bool mask_to_left = (opcode == BPF_ADD && off_is_neg) || | |
5863 | (opcode == BPF_SUB && !off_is_neg); | |
1b1597e6 | 5864 | u32 off, max; |
979d63d5 DB |
5865 | |
5866 | switch (ptr_reg->type) { | |
5867 | case PTR_TO_STACK: | |
1b1597e6 PK |
5868 | /* Offset 0 is out-of-bounds, but acceptable start for the |
5869 | * left direction, see BPF_REG_FP. | |
5870 | */ | |
5871 | max = MAX_BPF_STACK + mask_to_left; | |
088ec26d AI |
5872 | /* Indirect variable offset stack access is prohibited in |
5873 | * unprivileged mode so it's not handled here. | |
5874 | */ | |
979d63d5 DB |
5875 | off = ptr_reg->off + ptr_reg->var_off.value; |
5876 | if (mask_to_left) | |
b5871dca | 5877 | *ptr_limit = MAX_BPF_STACK + off; |
979d63d5 | 5878 | else |
b5871dca | 5879 | *ptr_limit = -off - 1; |
1b1597e6 | 5880 | return *ptr_limit >= max ? -ERANGE : 0; |
979d63d5 | 5881 | case PTR_TO_MAP_VALUE: |
1b1597e6 | 5882 | max = ptr_reg->map_ptr->value_size; |
979d63d5 | 5883 | if (mask_to_left) { |
b5871dca | 5884 | *ptr_limit = ptr_reg->umax_value + ptr_reg->off; |
979d63d5 DB |
5885 | } else { |
5886 | off = ptr_reg->smin_value + ptr_reg->off; | |
b5871dca | 5887 | *ptr_limit = ptr_reg->map_ptr->value_size - off - 1; |
979d63d5 | 5888 | } |
1b1597e6 | 5889 | return *ptr_limit >= max ? -ERANGE : 0; |
979d63d5 DB |
5890 | default: |
5891 | return -EINVAL; | |
5892 | } | |
5893 | } | |
5894 | ||
d3bd7413 DB |
5895 | static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env, |
5896 | const struct bpf_insn *insn) | |
5897 | { | |
2c78ee89 | 5898 | return env->bypass_spec_v1 || BPF_SRC(insn->code) == BPF_K; |
d3bd7413 DB |
5899 | } |
5900 | ||
5901 | static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux, | |
5902 | u32 alu_state, u32 alu_limit) | |
5903 | { | |
5904 | /* If we arrived here from different branches with different | |
5905 | * state or limits to sanitize, then this won't work. | |
5906 | */ | |
5907 | if (aux->alu_state && | |
5908 | (aux->alu_state != alu_state || | |
5909 | aux->alu_limit != alu_limit)) | |
5910 | return -EACCES; | |
5911 | ||
5912 | /* Corresponding fixup done in fixup_bpf_calls(). */ | |
5913 | aux->alu_state = alu_state; | |
5914 | aux->alu_limit = alu_limit; | |
5915 | return 0; | |
5916 | } | |
5917 | ||
5918 | static int sanitize_val_alu(struct bpf_verifier_env *env, | |
5919 | struct bpf_insn *insn) | |
5920 | { | |
5921 | struct bpf_insn_aux_data *aux = cur_aux(env); | |
5922 | ||
5923 | if (can_skip_alu_sanitation(env, insn)) | |
5924 | return 0; | |
5925 | ||
5926 | return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0); | |
5927 | } | |
5928 | ||
979d63d5 DB |
5929 | static int sanitize_ptr_alu(struct bpf_verifier_env *env, |
5930 | struct bpf_insn *insn, | |
5931 | const struct bpf_reg_state *ptr_reg, | |
5932 | struct bpf_reg_state *dst_reg, | |
5933 | bool off_is_neg) | |
5934 | { | |
5935 | struct bpf_verifier_state *vstate = env->cur_state; | |
5936 | struct bpf_insn_aux_data *aux = cur_aux(env); | |
5937 | bool ptr_is_dst_reg = ptr_reg == dst_reg; | |
5938 | u8 opcode = BPF_OP(insn->code); | |
5939 | u32 alu_state, alu_limit; | |
5940 | struct bpf_reg_state tmp; | |
5941 | bool ret; | |
f232326f | 5942 | int err; |
979d63d5 | 5943 | |
d3bd7413 | 5944 | if (can_skip_alu_sanitation(env, insn)) |
979d63d5 DB |
5945 | return 0; |
5946 | ||
5947 | /* We already marked aux for masking from non-speculative | |
5948 | * paths, thus we got here in the first place. We only care | |
5949 | * to explore bad access from here. | |
5950 | */ | |
5951 | if (vstate->speculative) | |
5952 | goto do_sim; | |
5953 | ||
5954 | alu_state = off_is_neg ? BPF_ALU_NEG_VALUE : 0; | |
5955 | alu_state |= ptr_is_dst_reg ? | |
5956 | BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST; | |
5957 | ||
f232326f PK |
5958 | err = retrieve_ptr_limit(ptr_reg, &alu_limit, opcode, off_is_neg); |
5959 | if (err < 0) | |
5960 | return err; | |
5961 | ||
5962 | err = update_alu_sanitation_state(aux, alu_state, alu_limit); | |
5963 | if (err < 0) | |
5964 | return err; | |
979d63d5 DB |
5965 | do_sim: |
5966 | /* Simulate and find potential out-of-bounds access under | |
5967 | * speculative execution from truncation as a result of | |
5968 | * masking when off was not within expected range. If off | |
5969 | * sits in dst, then we temporarily need to move ptr there | |
5970 | * to simulate dst (== 0) +/-= ptr. Needed, for example, | |
5971 | * for cases where we use K-based arithmetic in one direction | |
5972 | * and truncated reg-based in the other in order to explore | |
5973 | * bad access. | |
5974 | */ | |
5975 | if (!ptr_is_dst_reg) { | |
5976 | tmp = *dst_reg; | |
5977 | *dst_reg = *ptr_reg; | |
5978 | } | |
5979 | ret = push_stack(env, env->insn_idx + 1, env->insn_idx, true); | |
0803278b | 5980 | if (!ptr_is_dst_reg && ret) |
979d63d5 DB |
5981 | *dst_reg = tmp; |
5982 | return !ret ? -EFAULT : 0; | |
5983 | } | |
5984 | ||
01f810ac AM |
5985 | /* check that stack access falls within stack limits and that 'reg' doesn't |
5986 | * have a variable offset. | |
5987 | * | |
5988 | * Variable offset is prohibited for unprivileged mode for simplicity since it | |
5989 | * requires corresponding support in Spectre masking for stack ALU. See also | |
5990 | * retrieve_ptr_limit(). | |
5991 | * | |
5992 | * | |
5993 | * 'off' includes 'reg->off'. | |
5994 | */ | |
5995 | static int check_stack_access_for_ptr_arithmetic( | |
5996 | struct bpf_verifier_env *env, | |
5997 | int regno, | |
5998 | const struct bpf_reg_state *reg, | |
5999 | int off) | |
6000 | { | |
6001 | if (!tnum_is_const(reg->var_off)) { | |
6002 | char tn_buf[48]; | |
6003 | ||
6004 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
6005 | verbose(env, "R%d variable stack access prohibited for !root, var_off=%s off=%d\n", | |
6006 | regno, tn_buf, off); | |
6007 | return -EACCES; | |
6008 | } | |
6009 | ||
6010 | if (off >= 0 || off < -MAX_BPF_STACK) { | |
6011 | verbose(env, "R%d stack pointer arithmetic goes out of range, " | |
6012 | "prohibited for !root; off=%d\n", regno, off); | |
6013 | return -EACCES; | |
6014 | } | |
6015 | ||
6016 | return 0; | |
6017 | } | |
6018 | ||
6019 | ||
f1174f77 | 6020 | /* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off. |
f1174f77 EC |
6021 | * Caller should also handle BPF_MOV case separately. |
6022 | * If we return -EACCES, caller may want to try again treating pointer as a | |
6023 | * scalar. So we only emit a diagnostic if !env->allow_ptr_leaks. | |
6024 | */ | |
6025 | static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, | |
6026 | struct bpf_insn *insn, | |
6027 | const struct bpf_reg_state *ptr_reg, | |
6028 | const struct bpf_reg_state *off_reg) | |
969bf05e | 6029 | { |
f4d7e40a AS |
6030 | struct bpf_verifier_state *vstate = env->cur_state; |
6031 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
6032 | struct bpf_reg_state *regs = state->regs, *dst_reg; | |
f1174f77 | 6033 | bool known = tnum_is_const(off_reg->var_off); |
b03c9f9f EC |
6034 | s64 smin_val = off_reg->smin_value, smax_val = off_reg->smax_value, |
6035 | smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value; | |
6036 | u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value, | |
6037 | umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value; | |
9d7eceed | 6038 | u32 dst = insn->dst_reg, src = insn->src_reg; |
969bf05e | 6039 | u8 opcode = BPF_OP(insn->code); |
979d63d5 | 6040 | int ret; |
969bf05e | 6041 | |
f1174f77 | 6042 | dst_reg = ®s[dst]; |
969bf05e | 6043 | |
6f16101e DB |
6044 | if ((known && (smin_val != smax_val || umin_val != umax_val)) || |
6045 | smin_val > smax_val || umin_val > umax_val) { | |
6046 | /* Taint dst register if offset had invalid bounds derived from | |
6047 | * e.g. dead branches. | |
6048 | */ | |
f54c7898 | 6049 | __mark_reg_unknown(env, dst_reg); |
6f16101e | 6050 | return 0; |
f1174f77 EC |
6051 | } |
6052 | ||
6053 | if (BPF_CLASS(insn->code) != BPF_ALU64) { | |
6054 | /* 32-bit ALU ops on pointers produce (meaningless) scalars */ | |
6c693541 YS |
6055 | if (opcode == BPF_SUB && env->allow_ptr_leaks) { |
6056 | __mark_reg_unknown(env, dst_reg); | |
6057 | return 0; | |
6058 | } | |
6059 | ||
82abbf8d AS |
6060 | verbose(env, |
6061 | "R%d 32-bit pointer arithmetic prohibited\n", | |
6062 | dst); | |
f1174f77 | 6063 | return -EACCES; |
969bf05e AS |
6064 | } |
6065 | ||
aad2eeaf JS |
6066 | switch (ptr_reg->type) { |
6067 | case PTR_TO_MAP_VALUE_OR_NULL: | |
6068 | verbose(env, "R%d pointer arithmetic on %s prohibited, null-check it first\n", | |
6069 | dst, reg_type_str[ptr_reg->type]); | |
f1174f77 | 6070 | return -EACCES; |
aad2eeaf | 6071 | case CONST_PTR_TO_MAP: |
7c696732 YS |
6072 | /* smin_val represents the known value */ |
6073 | if (known && smin_val == 0 && opcode == BPF_ADD) | |
6074 | break; | |
8731745e | 6075 | fallthrough; |
aad2eeaf | 6076 | case PTR_TO_PACKET_END: |
c64b7983 JS |
6077 | case PTR_TO_SOCKET: |
6078 | case PTR_TO_SOCKET_OR_NULL: | |
46f8bc92 MKL |
6079 | case PTR_TO_SOCK_COMMON: |
6080 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
655a51e5 MKL |
6081 | case PTR_TO_TCP_SOCK: |
6082 | case PTR_TO_TCP_SOCK_OR_NULL: | |
fada7fdc | 6083 | case PTR_TO_XDP_SOCK: |
aad2eeaf JS |
6084 | verbose(env, "R%d pointer arithmetic on %s prohibited\n", |
6085 | dst, reg_type_str[ptr_reg->type]); | |
f1174f77 | 6086 | return -EACCES; |
9d7eceed | 6087 | case PTR_TO_MAP_VALUE: |
96011483 | 6088 | if (!env->env->bypass_spec_v1 && !known && (smin_val < 0) != (smax_val < 0)) { |
9d7eceed DB |
6089 | verbose(env, "R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n", |
6090 | off_reg == dst_reg ? dst : src); | |
6091 | return -EACCES; | |
6092 | } | |
df561f66 | 6093 | fallthrough; |
aad2eeaf JS |
6094 | default: |
6095 | break; | |
f1174f77 EC |
6096 | } |
6097 | ||
6098 | /* In case of 'scalar += pointer', dst_reg inherits pointer type and id. | |
6099 | * The id may be overwritten later if we create a new variable offset. | |
969bf05e | 6100 | */ |
f1174f77 EC |
6101 | dst_reg->type = ptr_reg->type; |
6102 | dst_reg->id = ptr_reg->id; | |
969bf05e | 6103 | |
bb7f0f98 AS |
6104 | if (!check_reg_sane_offset(env, off_reg, ptr_reg->type) || |
6105 | !check_reg_sane_offset(env, ptr_reg, ptr_reg->type)) | |
6106 | return -EINVAL; | |
6107 | ||
3f50f132 JF |
6108 | /* pointer types do not carry 32-bit bounds at the moment. */ |
6109 | __mark_reg32_unbounded(dst_reg); | |
6110 | ||
f1174f77 EC |
6111 | switch (opcode) { |
6112 | case BPF_ADD: | |
979d63d5 DB |
6113 | ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0); |
6114 | if (ret < 0) { | |
f232326f | 6115 | verbose(env, "R%d tried to add from different maps, paths, or prohibited types\n", dst); |
979d63d5 DB |
6116 | return ret; |
6117 | } | |
f1174f77 EC |
6118 | /* We can take a fixed offset as long as it doesn't overflow |
6119 | * the s32 'off' field | |
969bf05e | 6120 | */ |
b03c9f9f EC |
6121 | if (known && (ptr_reg->off + smin_val == |
6122 | (s64)(s32)(ptr_reg->off + smin_val))) { | |
f1174f77 | 6123 | /* pointer += K. Accumulate it into fixed offset */ |
b03c9f9f EC |
6124 | dst_reg->smin_value = smin_ptr; |
6125 | dst_reg->smax_value = smax_ptr; | |
6126 | dst_reg->umin_value = umin_ptr; | |
6127 | dst_reg->umax_value = umax_ptr; | |
f1174f77 | 6128 | dst_reg->var_off = ptr_reg->var_off; |
b03c9f9f | 6129 | dst_reg->off = ptr_reg->off + smin_val; |
0962590e | 6130 | dst_reg->raw = ptr_reg->raw; |
f1174f77 EC |
6131 | break; |
6132 | } | |
f1174f77 EC |
6133 | /* A new variable offset is created. Note that off_reg->off |
6134 | * == 0, since it's a scalar. | |
6135 | * dst_reg gets the pointer type and since some positive | |
6136 | * integer value was added to the pointer, give it a new 'id' | |
6137 | * if it's a PTR_TO_PACKET. | |
6138 | * this creates a new 'base' pointer, off_reg (variable) gets | |
6139 | * added into the variable offset, and we copy the fixed offset | |
6140 | * from ptr_reg. | |
969bf05e | 6141 | */ |
b03c9f9f EC |
6142 | if (signed_add_overflows(smin_ptr, smin_val) || |
6143 | signed_add_overflows(smax_ptr, smax_val)) { | |
6144 | dst_reg->smin_value = S64_MIN; | |
6145 | dst_reg->smax_value = S64_MAX; | |
6146 | } else { | |
6147 | dst_reg->smin_value = smin_ptr + smin_val; | |
6148 | dst_reg->smax_value = smax_ptr + smax_val; | |
6149 | } | |
6150 | if (umin_ptr + umin_val < umin_ptr || | |
6151 | umax_ptr + umax_val < umax_ptr) { | |
6152 | dst_reg->umin_value = 0; | |
6153 | dst_reg->umax_value = U64_MAX; | |
6154 | } else { | |
6155 | dst_reg->umin_value = umin_ptr + umin_val; | |
6156 | dst_reg->umax_value = umax_ptr + umax_val; | |
6157 | } | |
f1174f77 EC |
6158 | dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off); |
6159 | dst_reg->off = ptr_reg->off; | |
0962590e | 6160 | dst_reg->raw = ptr_reg->raw; |
de8f3a83 | 6161 | if (reg_is_pkt_pointer(ptr_reg)) { |
f1174f77 EC |
6162 | dst_reg->id = ++env->id_gen; |
6163 | /* something was added to pkt_ptr, set range to zero */ | |
22dc4a0f | 6164 | memset(&dst_reg->raw, 0, sizeof(dst_reg->raw)); |
f1174f77 EC |
6165 | } |
6166 | break; | |
6167 | case BPF_SUB: | |
979d63d5 DB |
6168 | ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0); |
6169 | if (ret < 0) { | |
f232326f | 6170 | verbose(env, "R%d tried to sub from different maps, paths, or prohibited types\n", dst); |
979d63d5 DB |
6171 | return ret; |
6172 | } | |
f1174f77 EC |
6173 | if (dst_reg == off_reg) { |
6174 | /* scalar -= pointer. Creates an unknown scalar */ | |
82abbf8d AS |
6175 | verbose(env, "R%d tried to subtract pointer from scalar\n", |
6176 | dst); | |
f1174f77 EC |
6177 | return -EACCES; |
6178 | } | |
6179 | /* We don't allow subtraction from FP, because (according to | |
6180 | * test_verifier.c test "invalid fp arithmetic", JITs might not | |
6181 | * be able to deal with it. | |
969bf05e | 6182 | */ |
f1174f77 | 6183 | if (ptr_reg->type == PTR_TO_STACK) { |
82abbf8d AS |
6184 | verbose(env, "R%d subtraction from stack pointer prohibited\n", |
6185 | dst); | |
f1174f77 EC |
6186 | return -EACCES; |
6187 | } | |
b03c9f9f EC |
6188 | if (known && (ptr_reg->off - smin_val == |
6189 | (s64)(s32)(ptr_reg->off - smin_val))) { | |
f1174f77 | 6190 | /* pointer -= K. Subtract it from fixed offset */ |
b03c9f9f EC |
6191 | dst_reg->smin_value = smin_ptr; |
6192 | dst_reg->smax_value = smax_ptr; | |
6193 | dst_reg->umin_value = umin_ptr; | |
6194 | dst_reg->umax_value = umax_ptr; | |
f1174f77 EC |
6195 | dst_reg->var_off = ptr_reg->var_off; |
6196 | dst_reg->id = ptr_reg->id; | |
b03c9f9f | 6197 | dst_reg->off = ptr_reg->off - smin_val; |
0962590e | 6198 | dst_reg->raw = ptr_reg->raw; |
f1174f77 EC |
6199 | break; |
6200 | } | |
f1174f77 EC |
6201 | /* A new variable offset is created. If the subtrahend is known |
6202 | * nonnegative, then any reg->range we had before is still good. | |
969bf05e | 6203 | */ |
b03c9f9f EC |
6204 | if (signed_sub_overflows(smin_ptr, smax_val) || |
6205 | signed_sub_overflows(smax_ptr, smin_val)) { | |
6206 | /* Overflow possible, we know nothing */ | |
6207 | dst_reg->smin_value = S64_MIN; | |
6208 | dst_reg->smax_value = S64_MAX; | |
6209 | } else { | |
6210 | dst_reg->smin_value = smin_ptr - smax_val; | |
6211 | dst_reg->smax_value = smax_ptr - smin_val; | |
6212 | } | |
6213 | if (umin_ptr < umax_val) { | |
6214 | /* Overflow possible, we know nothing */ | |
6215 | dst_reg->umin_value = 0; | |
6216 | dst_reg->umax_value = U64_MAX; | |
6217 | } else { | |
6218 | /* Cannot overflow (as long as bounds are consistent) */ | |
6219 | dst_reg->umin_value = umin_ptr - umax_val; | |
6220 | dst_reg->umax_value = umax_ptr - umin_val; | |
6221 | } | |
f1174f77 EC |
6222 | dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off); |
6223 | dst_reg->off = ptr_reg->off; | |
0962590e | 6224 | dst_reg->raw = ptr_reg->raw; |
de8f3a83 | 6225 | if (reg_is_pkt_pointer(ptr_reg)) { |
f1174f77 EC |
6226 | dst_reg->id = ++env->id_gen; |
6227 | /* something was added to pkt_ptr, set range to zero */ | |
b03c9f9f | 6228 | if (smin_val < 0) |
22dc4a0f | 6229 | memset(&dst_reg->raw, 0, sizeof(dst_reg->raw)); |
43188702 | 6230 | } |
f1174f77 EC |
6231 | break; |
6232 | case BPF_AND: | |
6233 | case BPF_OR: | |
6234 | case BPF_XOR: | |
82abbf8d AS |
6235 | /* bitwise ops on pointers are troublesome, prohibit. */ |
6236 | verbose(env, "R%d bitwise operator %s on pointer prohibited\n", | |
6237 | dst, bpf_alu_string[opcode >> 4]); | |
f1174f77 EC |
6238 | return -EACCES; |
6239 | default: | |
6240 | /* other operators (e.g. MUL,LSH) produce non-pointer results */ | |
82abbf8d AS |
6241 | verbose(env, "R%d pointer arithmetic with %s operator prohibited\n", |
6242 | dst, bpf_alu_string[opcode >> 4]); | |
f1174f77 | 6243 | return -EACCES; |
43188702 JF |
6244 | } |
6245 | ||
bb7f0f98 AS |
6246 | if (!check_reg_sane_offset(env, dst_reg, ptr_reg->type)) |
6247 | return -EINVAL; | |
6248 | ||
b03c9f9f EC |
6249 | __update_reg_bounds(dst_reg); |
6250 | __reg_deduce_bounds(dst_reg); | |
6251 | __reg_bound_offset(dst_reg); | |
0d6303db DB |
6252 | |
6253 | /* For unprivileged we require that resulting offset must be in bounds | |
6254 | * in order to be able to sanitize access later on. | |
6255 | */ | |
2c78ee89 | 6256 | if (!env->bypass_spec_v1) { |
e4298d25 DB |
6257 | if (dst_reg->type == PTR_TO_MAP_VALUE && |
6258 | check_map_access(env, dst, dst_reg->off, 1, false)) { | |
6259 | verbose(env, "R%d pointer arithmetic of map value goes out of range, " | |
6260 | "prohibited for !root\n", dst); | |
6261 | return -EACCES; | |
6262 | } else if (dst_reg->type == PTR_TO_STACK && | |
01f810ac AM |
6263 | check_stack_access_for_ptr_arithmetic( |
6264 | env, dst, dst_reg, dst_reg->off + | |
6265 | dst_reg->var_off.value)) { | |
e4298d25 DB |
6266 | return -EACCES; |
6267 | } | |
0d6303db DB |
6268 | } |
6269 | ||
43188702 JF |
6270 | return 0; |
6271 | } | |
6272 | ||
3f50f132 JF |
6273 | static void scalar32_min_max_add(struct bpf_reg_state *dst_reg, |
6274 | struct bpf_reg_state *src_reg) | |
6275 | { | |
6276 | s32 smin_val = src_reg->s32_min_value; | |
6277 | s32 smax_val = src_reg->s32_max_value; | |
6278 | u32 umin_val = src_reg->u32_min_value; | |
6279 | u32 umax_val = src_reg->u32_max_value; | |
6280 | ||
6281 | if (signed_add32_overflows(dst_reg->s32_min_value, smin_val) || | |
6282 | signed_add32_overflows(dst_reg->s32_max_value, smax_val)) { | |
6283 | dst_reg->s32_min_value = S32_MIN; | |
6284 | dst_reg->s32_max_value = S32_MAX; | |
6285 | } else { | |
6286 | dst_reg->s32_min_value += smin_val; | |
6287 | dst_reg->s32_max_value += smax_val; | |
6288 | } | |
6289 | if (dst_reg->u32_min_value + umin_val < umin_val || | |
6290 | dst_reg->u32_max_value + umax_val < umax_val) { | |
6291 | dst_reg->u32_min_value = 0; | |
6292 | dst_reg->u32_max_value = U32_MAX; | |
6293 | } else { | |
6294 | dst_reg->u32_min_value += umin_val; | |
6295 | dst_reg->u32_max_value += umax_val; | |
6296 | } | |
6297 | } | |
6298 | ||
07cd2631 JF |
6299 | static void scalar_min_max_add(struct bpf_reg_state *dst_reg, |
6300 | struct bpf_reg_state *src_reg) | |
6301 | { | |
6302 | s64 smin_val = src_reg->smin_value; | |
6303 | s64 smax_val = src_reg->smax_value; | |
6304 | u64 umin_val = src_reg->umin_value; | |
6305 | u64 umax_val = src_reg->umax_value; | |
6306 | ||
6307 | if (signed_add_overflows(dst_reg->smin_value, smin_val) || | |
6308 | signed_add_overflows(dst_reg->smax_value, smax_val)) { | |
6309 | dst_reg->smin_value = S64_MIN; | |
6310 | dst_reg->smax_value = S64_MAX; | |
6311 | } else { | |
6312 | dst_reg->smin_value += smin_val; | |
6313 | dst_reg->smax_value += smax_val; | |
6314 | } | |
6315 | if (dst_reg->umin_value + umin_val < umin_val || | |
6316 | dst_reg->umax_value + umax_val < umax_val) { | |
6317 | dst_reg->umin_value = 0; | |
6318 | dst_reg->umax_value = U64_MAX; | |
6319 | } else { | |
6320 | dst_reg->umin_value += umin_val; | |
6321 | dst_reg->umax_value += umax_val; | |
6322 | } | |
3f50f132 JF |
6323 | } |
6324 | ||
6325 | static void scalar32_min_max_sub(struct bpf_reg_state *dst_reg, | |
6326 | struct bpf_reg_state *src_reg) | |
6327 | { | |
6328 | s32 smin_val = src_reg->s32_min_value; | |
6329 | s32 smax_val = src_reg->s32_max_value; | |
6330 | u32 umin_val = src_reg->u32_min_value; | |
6331 | u32 umax_val = src_reg->u32_max_value; | |
6332 | ||
6333 | if (signed_sub32_overflows(dst_reg->s32_min_value, smax_val) || | |
6334 | signed_sub32_overflows(dst_reg->s32_max_value, smin_val)) { | |
6335 | /* Overflow possible, we know nothing */ | |
6336 | dst_reg->s32_min_value = S32_MIN; | |
6337 | dst_reg->s32_max_value = S32_MAX; | |
6338 | } else { | |
6339 | dst_reg->s32_min_value -= smax_val; | |
6340 | dst_reg->s32_max_value -= smin_val; | |
6341 | } | |
6342 | if (dst_reg->u32_min_value < umax_val) { | |
6343 | /* Overflow possible, we know nothing */ | |
6344 | dst_reg->u32_min_value = 0; | |
6345 | dst_reg->u32_max_value = U32_MAX; | |
6346 | } else { | |
6347 | /* Cannot overflow (as long as bounds are consistent) */ | |
6348 | dst_reg->u32_min_value -= umax_val; | |
6349 | dst_reg->u32_max_value -= umin_val; | |
6350 | } | |
07cd2631 JF |
6351 | } |
6352 | ||
6353 | static void scalar_min_max_sub(struct bpf_reg_state *dst_reg, | |
6354 | struct bpf_reg_state *src_reg) | |
6355 | { | |
6356 | s64 smin_val = src_reg->smin_value; | |
6357 | s64 smax_val = src_reg->smax_value; | |
6358 | u64 umin_val = src_reg->umin_value; | |
6359 | u64 umax_val = src_reg->umax_value; | |
6360 | ||
6361 | if (signed_sub_overflows(dst_reg->smin_value, smax_val) || | |
6362 | signed_sub_overflows(dst_reg->smax_value, smin_val)) { | |
6363 | /* Overflow possible, we know nothing */ | |
6364 | dst_reg->smin_value = S64_MIN; | |
6365 | dst_reg->smax_value = S64_MAX; | |
6366 | } else { | |
6367 | dst_reg->smin_value -= smax_val; | |
6368 | dst_reg->smax_value -= smin_val; | |
6369 | } | |
6370 | if (dst_reg->umin_value < umax_val) { | |
6371 | /* Overflow possible, we know nothing */ | |
6372 | dst_reg->umin_value = 0; | |
6373 | dst_reg->umax_value = U64_MAX; | |
6374 | } else { | |
6375 | /* Cannot overflow (as long as bounds are consistent) */ | |
6376 | dst_reg->umin_value -= umax_val; | |
6377 | dst_reg->umax_value -= umin_val; | |
6378 | } | |
3f50f132 JF |
6379 | } |
6380 | ||
6381 | static void scalar32_min_max_mul(struct bpf_reg_state *dst_reg, | |
6382 | struct bpf_reg_state *src_reg) | |
6383 | { | |
6384 | s32 smin_val = src_reg->s32_min_value; | |
6385 | u32 umin_val = src_reg->u32_min_value; | |
6386 | u32 umax_val = src_reg->u32_max_value; | |
6387 | ||
6388 | if (smin_val < 0 || dst_reg->s32_min_value < 0) { | |
6389 | /* Ain't nobody got time to multiply that sign */ | |
6390 | __mark_reg32_unbounded(dst_reg); | |
6391 | return; | |
6392 | } | |
6393 | /* Both values are positive, so we can work with unsigned and | |
6394 | * copy the result to signed (unless it exceeds S32_MAX). | |
6395 | */ | |
6396 | if (umax_val > U16_MAX || dst_reg->u32_max_value > U16_MAX) { | |
6397 | /* Potential overflow, we know nothing */ | |
6398 | __mark_reg32_unbounded(dst_reg); | |
6399 | return; | |
6400 | } | |
6401 | dst_reg->u32_min_value *= umin_val; | |
6402 | dst_reg->u32_max_value *= umax_val; | |
6403 | if (dst_reg->u32_max_value > S32_MAX) { | |
6404 | /* Overflow possible, we know nothing */ | |
6405 | dst_reg->s32_min_value = S32_MIN; | |
6406 | dst_reg->s32_max_value = S32_MAX; | |
6407 | } else { | |
6408 | dst_reg->s32_min_value = dst_reg->u32_min_value; | |
6409 | dst_reg->s32_max_value = dst_reg->u32_max_value; | |
6410 | } | |
07cd2631 JF |
6411 | } |
6412 | ||
6413 | static void scalar_min_max_mul(struct bpf_reg_state *dst_reg, | |
6414 | struct bpf_reg_state *src_reg) | |
6415 | { | |
6416 | s64 smin_val = src_reg->smin_value; | |
6417 | u64 umin_val = src_reg->umin_value; | |
6418 | u64 umax_val = src_reg->umax_value; | |
6419 | ||
07cd2631 JF |
6420 | if (smin_val < 0 || dst_reg->smin_value < 0) { |
6421 | /* Ain't nobody got time to multiply that sign */ | |
3f50f132 | 6422 | __mark_reg64_unbounded(dst_reg); |
07cd2631 JF |
6423 | return; |
6424 | } | |
6425 | /* Both values are positive, so we can work with unsigned and | |
6426 | * copy the result to signed (unless it exceeds S64_MAX). | |
6427 | */ | |
6428 | if (umax_val > U32_MAX || dst_reg->umax_value > U32_MAX) { | |
6429 | /* Potential overflow, we know nothing */ | |
3f50f132 | 6430 | __mark_reg64_unbounded(dst_reg); |
07cd2631 JF |
6431 | return; |
6432 | } | |
6433 | dst_reg->umin_value *= umin_val; | |
6434 | dst_reg->umax_value *= umax_val; | |
6435 | if (dst_reg->umax_value > S64_MAX) { | |
6436 | /* Overflow possible, we know nothing */ | |
6437 | dst_reg->smin_value = S64_MIN; | |
6438 | dst_reg->smax_value = S64_MAX; | |
6439 | } else { | |
6440 | dst_reg->smin_value = dst_reg->umin_value; | |
6441 | dst_reg->smax_value = dst_reg->umax_value; | |
6442 | } | |
6443 | } | |
6444 | ||
3f50f132 JF |
6445 | static void scalar32_min_max_and(struct bpf_reg_state *dst_reg, |
6446 | struct bpf_reg_state *src_reg) | |
6447 | { | |
6448 | bool src_known = tnum_subreg_is_const(src_reg->var_off); | |
6449 | bool dst_known = tnum_subreg_is_const(dst_reg->var_off); | |
6450 | struct tnum var32_off = tnum_subreg(dst_reg->var_off); | |
6451 | s32 smin_val = src_reg->s32_min_value; | |
6452 | u32 umax_val = src_reg->u32_max_value; | |
6453 | ||
6454 | /* Assuming scalar64_min_max_and will be called so its safe | |
6455 | * to skip updating register for known 32-bit case. | |
6456 | */ | |
6457 | if (src_known && dst_known) | |
6458 | return; | |
6459 | ||
6460 | /* We get our minimum from the var_off, since that's inherently | |
6461 | * bitwise. Our maximum is the minimum of the operands' maxima. | |
6462 | */ | |
6463 | dst_reg->u32_min_value = var32_off.value; | |
6464 | dst_reg->u32_max_value = min(dst_reg->u32_max_value, umax_val); | |
6465 | if (dst_reg->s32_min_value < 0 || smin_val < 0) { | |
6466 | /* Lose signed bounds when ANDing negative numbers, | |
6467 | * ain't nobody got time for that. | |
6468 | */ | |
6469 | dst_reg->s32_min_value = S32_MIN; | |
6470 | dst_reg->s32_max_value = S32_MAX; | |
6471 | } else { | |
6472 | /* ANDing two positives gives a positive, so safe to | |
6473 | * cast result into s64. | |
6474 | */ | |
6475 | dst_reg->s32_min_value = dst_reg->u32_min_value; | |
6476 | dst_reg->s32_max_value = dst_reg->u32_max_value; | |
6477 | } | |
6478 | ||
6479 | } | |
6480 | ||
07cd2631 JF |
6481 | static void scalar_min_max_and(struct bpf_reg_state *dst_reg, |
6482 | struct bpf_reg_state *src_reg) | |
6483 | { | |
3f50f132 JF |
6484 | bool src_known = tnum_is_const(src_reg->var_off); |
6485 | bool dst_known = tnum_is_const(dst_reg->var_off); | |
07cd2631 JF |
6486 | s64 smin_val = src_reg->smin_value; |
6487 | u64 umax_val = src_reg->umax_value; | |
6488 | ||
3f50f132 | 6489 | if (src_known && dst_known) { |
4fbb38a3 | 6490 | __mark_reg_known(dst_reg, dst_reg->var_off.value); |
3f50f132 JF |
6491 | return; |
6492 | } | |
6493 | ||
07cd2631 JF |
6494 | /* We get our minimum from the var_off, since that's inherently |
6495 | * bitwise. Our maximum is the minimum of the operands' maxima. | |
6496 | */ | |
07cd2631 JF |
6497 | dst_reg->umin_value = dst_reg->var_off.value; |
6498 | dst_reg->umax_value = min(dst_reg->umax_value, umax_val); | |
6499 | if (dst_reg->smin_value < 0 || smin_val < 0) { | |
6500 | /* Lose signed bounds when ANDing negative numbers, | |
6501 | * ain't nobody got time for that. | |
6502 | */ | |
6503 | dst_reg->smin_value = S64_MIN; | |
6504 | dst_reg->smax_value = S64_MAX; | |
6505 | } else { | |
6506 | /* ANDing two positives gives a positive, so safe to | |
6507 | * cast result into s64. | |
6508 | */ | |
6509 | dst_reg->smin_value = dst_reg->umin_value; | |
6510 | dst_reg->smax_value = dst_reg->umax_value; | |
6511 | } | |
6512 | /* We may learn something more from the var_off */ | |
6513 | __update_reg_bounds(dst_reg); | |
6514 | } | |
6515 | ||
3f50f132 JF |
6516 | static void scalar32_min_max_or(struct bpf_reg_state *dst_reg, |
6517 | struct bpf_reg_state *src_reg) | |
6518 | { | |
6519 | bool src_known = tnum_subreg_is_const(src_reg->var_off); | |
6520 | bool dst_known = tnum_subreg_is_const(dst_reg->var_off); | |
6521 | struct tnum var32_off = tnum_subreg(dst_reg->var_off); | |
5b9fbeb7 DB |
6522 | s32 smin_val = src_reg->s32_min_value; |
6523 | u32 umin_val = src_reg->u32_min_value; | |
3f50f132 JF |
6524 | |
6525 | /* Assuming scalar64_min_max_or will be called so it is safe | |
6526 | * to skip updating register for known case. | |
6527 | */ | |
6528 | if (src_known && dst_known) | |
6529 | return; | |
6530 | ||
6531 | /* We get our maximum from the var_off, and our minimum is the | |
6532 | * maximum of the operands' minima | |
6533 | */ | |
6534 | dst_reg->u32_min_value = max(dst_reg->u32_min_value, umin_val); | |
6535 | dst_reg->u32_max_value = var32_off.value | var32_off.mask; | |
6536 | if (dst_reg->s32_min_value < 0 || smin_val < 0) { | |
6537 | /* Lose signed bounds when ORing negative numbers, | |
6538 | * ain't nobody got time for that. | |
6539 | */ | |
6540 | dst_reg->s32_min_value = S32_MIN; | |
6541 | dst_reg->s32_max_value = S32_MAX; | |
6542 | } else { | |
6543 | /* ORing two positives gives a positive, so safe to | |
6544 | * cast result into s64. | |
6545 | */ | |
5b9fbeb7 DB |
6546 | dst_reg->s32_min_value = dst_reg->u32_min_value; |
6547 | dst_reg->s32_max_value = dst_reg->u32_max_value; | |
3f50f132 JF |
6548 | } |
6549 | } | |
6550 | ||
07cd2631 JF |
6551 | static void scalar_min_max_or(struct bpf_reg_state *dst_reg, |
6552 | struct bpf_reg_state *src_reg) | |
6553 | { | |
3f50f132 JF |
6554 | bool src_known = tnum_is_const(src_reg->var_off); |
6555 | bool dst_known = tnum_is_const(dst_reg->var_off); | |
07cd2631 JF |
6556 | s64 smin_val = src_reg->smin_value; |
6557 | u64 umin_val = src_reg->umin_value; | |
6558 | ||
3f50f132 | 6559 | if (src_known && dst_known) { |
4fbb38a3 | 6560 | __mark_reg_known(dst_reg, dst_reg->var_off.value); |
3f50f132 JF |
6561 | return; |
6562 | } | |
6563 | ||
07cd2631 JF |
6564 | /* We get our maximum from the var_off, and our minimum is the |
6565 | * maximum of the operands' minima | |
6566 | */ | |
07cd2631 JF |
6567 | dst_reg->umin_value = max(dst_reg->umin_value, umin_val); |
6568 | dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask; | |
6569 | if (dst_reg->smin_value < 0 || smin_val < 0) { | |
6570 | /* Lose signed bounds when ORing negative numbers, | |
6571 | * ain't nobody got time for that. | |
6572 | */ | |
6573 | dst_reg->smin_value = S64_MIN; | |
6574 | dst_reg->smax_value = S64_MAX; | |
6575 | } else { | |
6576 | /* ORing two positives gives a positive, so safe to | |
6577 | * cast result into s64. | |
6578 | */ | |
6579 | dst_reg->smin_value = dst_reg->umin_value; | |
6580 | dst_reg->smax_value = dst_reg->umax_value; | |
6581 | } | |
6582 | /* We may learn something more from the var_off */ | |
6583 | __update_reg_bounds(dst_reg); | |
6584 | } | |
6585 | ||
2921c90d YS |
6586 | static void scalar32_min_max_xor(struct bpf_reg_state *dst_reg, |
6587 | struct bpf_reg_state *src_reg) | |
6588 | { | |
6589 | bool src_known = tnum_subreg_is_const(src_reg->var_off); | |
6590 | bool dst_known = tnum_subreg_is_const(dst_reg->var_off); | |
6591 | struct tnum var32_off = tnum_subreg(dst_reg->var_off); | |
6592 | s32 smin_val = src_reg->s32_min_value; | |
6593 | ||
6594 | /* Assuming scalar64_min_max_xor will be called so it is safe | |
6595 | * to skip updating register for known case. | |
6596 | */ | |
6597 | if (src_known && dst_known) | |
6598 | return; | |
6599 | ||
6600 | /* We get both minimum and maximum from the var32_off. */ | |
6601 | dst_reg->u32_min_value = var32_off.value; | |
6602 | dst_reg->u32_max_value = var32_off.value | var32_off.mask; | |
6603 | ||
6604 | if (dst_reg->s32_min_value >= 0 && smin_val >= 0) { | |
6605 | /* XORing two positive sign numbers gives a positive, | |
6606 | * so safe to cast u32 result into s32. | |
6607 | */ | |
6608 | dst_reg->s32_min_value = dst_reg->u32_min_value; | |
6609 | dst_reg->s32_max_value = dst_reg->u32_max_value; | |
6610 | } else { | |
6611 | dst_reg->s32_min_value = S32_MIN; | |
6612 | dst_reg->s32_max_value = S32_MAX; | |
6613 | } | |
6614 | } | |
6615 | ||
6616 | static void scalar_min_max_xor(struct bpf_reg_state *dst_reg, | |
6617 | struct bpf_reg_state *src_reg) | |
6618 | { | |
6619 | bool src_known = tnum_is_const(src_reg->var_off); | |
6620 | bool dst_known = tnum_is_const(dst_reg->var_off); | |
6621 | s64 smin_val = src_reg->smin_value; | |
6622 | ||
6623 | if (src_known && dst_known) { | |
6624 | /* dst_reg->var_off.value has been updated earlier */ | |
6625 | __mark_reg_known(dst_reg, dst_reg->var_off.value); | |
6626 | return; | |
6627 | } | |
6628 | ||
6629 | /* We get both minimum and maximum from the var_off. */ | |
6630 | dst_reg->umin_value = dst_reg->var_off.value; | |
6631 | dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask; | |
6632 | ||
6633 | if (dst_reg->smin_value >= 0 && smin_val >= 0) { | |
6634 | /* XORing two positive sign numbers gives a positive, | |
6635 | * so safe to cast u64 result into s64. | |
6636 | */ | |
6637 | dst_reg->smin_value = dst_reg->umin_value; | |
6638 | dst_reg->smax_value = dst_reg->umax_value; | |
6639 | } else { | |
6640 | dst_reg->smin_value = S64_MIN; | |
6641 | dst_reg->smax_value = S64_MAX; | |
6642 | } | |
6643 | ||
6644 | __update_reg_bounds(dst_reg); | |
6645 | } | |
6646 | ||
3f50f132 JF |
6647 | static void __scalar32_min_max_lsh(struct bpf_reg_state *dst_reg, |
6648 | u64 umin_val, u64 umax_val) | |
07cd2631 | 6649 | { |
07cd2631 JF |
6650 | /* We lose all sign bit information (except what we can pick |
6651 | * up from var_off) | |
6652 | */ | |
3f50f132 JF |
6653 | dst_reg->s32_min_value = S32_MIN; |
6654 | dst_reg->s32_max_value = S32_MAX; | |
6655 | /* If we might shift our top bit out, then we know nothing */ | |
6656 | if (umax_val > 31 || dst_reg->u32_max_value > 1ULL << (31 - umax_val)) { | |
6657 | dst_reg->u32_min_value = 0; | |
6658 | dst_reg->u32_max_value = U32_MAX; | |
6659 | } else { | |
6660 | dst_reg->u32_min_value <<= umin_val; | |
6661 | dst_reg->u32_max_value <<= umax_val; | |
6662 | } | |
6663 | } | |
6664 | ||
6665 | static void scalar32_min_max_lsh(struct bpf_reg_state *dst_reg, | |
6666 | struct bpf_reg_state *src_reg) | |
6667 | { | |
6668 | u32 umax_val = src_reg->u32_max_value; | |
6669 | u32 umin_val = src_reg->u32_min_value; | |
6670 | /* u32 alu operation will zext upper bits */ | |
6671 | struct tnum subreg = tnum_subreg(dst_reg->var_off); | |
6672 | ||
6673 | __scalar32_min_max_lsh(dst_reg, umin_val, umax_val); | |
6674 | dst_reg->var_off = tnum_subreg(tnum_lshift(subreg, umin_val)); | |
6675 | /* Not required but being careful mark reg64 bounds as unknown so | |
6676 | * that we are forced to pick them up from tnum and zext later and | |
6677 | * if some path skips this step we are still safe. | |
6678 | */ | |
6679 | __mark_reg64_unbounded(dst_reg); | |
6680 | __update_reg32_bounds(dst_reg); | |
6681 | } | |
6682 | ||
6683 | static void __scalar64_min_max_lsh(struct bpf_reg_state *dst_reg, | |
6684 | u64 umin_val, u64 umax_val) | |
6685 | { | |
6686 | /* Special case <<32 because it is a common compiler pattern to sign | |
6687 | * extend subreg by doing <<32 s>>32. In this case if 32bit bounds are | |
6688 | * positive we know this shift will also be positive so we can track | |
6689 | * bounds correctly. Otherwise we lose all sign bit information except | |
6690 | * what we can pick up from var_off. Perhaps we can generalize this | |
6691 | * later to shifts of any length. | |
6692 | */ | |
6693 | if (umin_val == 32 && umax_val == 32 && dst_reg->s32_max_value >= 0) | |
6694 | dst_reg->smax_value = (s64)dst_reg->s32_max_value << 32; | |
6695 | else | |
6696 | dst_reg->smax_value = S64_MAX; | |
6697 | ||
6698 | if (umin_val == 32 && umax_val == 32 && dst_reg->s32_min_value >= 0) | |
6699 | dst_reg->smin_value = (s64)dst_reg->s32_min_value << 32; | |
6700 | else | |
6701 | dst_reg->smin_value = S64_MIN; | |
6702 | ||
07cd2631 JF |
6703 | /* If we might shift our top bit out, then we know nothing */ |
6704 | if (dst_reg->umax_value > 1ULL << (63 - umax_val)) { | |
6705 | dst_reg->umin_value = 0; | |
6706 | dst_reg->umax_value = U64_MAX; | |
6707 | } else { | |
6708 | dst_reg->umin_value <<= umin_val; | |
6709 | dst_reg->umax_value <<= umax_val; | |
6710 | } | |
3f50f132 JF |
6711 | } |
6712 | ||
6713 | static void scalar_min_max_lsh(struct bpf_reg_state *dst_reg, | |
6714 | struct bpf_reg_state *src_reg) | |
6715 | { | |
6716 | u64 umax_val = src_reg->umax_value; | |
6717 | u64 umin_val = src_reg->umin_value; | |
6718 | ||
6719 | /* scalar64 calc uses 32bit unshifted bounds so must be called first */ | |
6720 | __scalar64_min_max_lsh(dst_reg, umin_val, umax_val); | |
6721 | __scalar32_min_max_lsh(dst_reg, umin_val, umax_val); | |
6722 | ||
07cd2631 JF |
6723 | dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val); |
6724 | /* We may learn something more from the var_off */ | |
6725 | __update_reg_bounds(dst_reg); | |
6726 | } | |
6727 | ||
3f50f132 JF |
6728 | static void scalar32_min_max_rsh(struct bpf_reg_state *dst_reg, |
6729 | struct bpf_reg_state *src_reg) | |
6730 | { | |
6731 | struct tnum subreg = tnum_subreg(dst_reg->var_off); | |
6732 | u32 umax_val = src_reg->u32_max_value; | |
6733 | u32 umin_val = src_reg->u32_min_value; | |
6734 | ||
6735 | /* BPF_RSH is an unsigned shift. If the value in dst_reg might | |
6736 | * be negative, then either: | |
6737 | * 1) src_reg might be zero, so the sign bit of the result is | |
6738 | * unknown, so we lose our signed bounds | |
6739 | * 2) it's known negative, thus the unsigned bounds capture the | |
6740 | * signed bounds | |
6741 | * 3) the signed bounds cross zero, so they tell us nothing | |
6742 | * about the result | |
6743 | * If the value in dst_reg is known nonnegative, then again the | |
18b24d78 | 6744 | * unsigned bounds capture the signed bounds. |
3f50f132 JF |
6745 | * Thus, in all cases it suffices to blow away our signed bounds |
6746 | * and rely on inferring new ones from the unsigned bounds and | |
6747 | * var_off of the result. | |
6748 | */ | |
6749 | dst_reg->s32_min_value = S32_MIN; | |
6750 | dst_reg->s32_max_value = S32_MAX; | |
6751 | ||
6752 | dst_reg->var_off = tnum_rshift(subreg, umin_val); | |
6753 | dst_reg->u32_min_value >>= umax_val; | |
6754 | dst_reg->u32_max_value >>= umin_val; | |
6755 | ||
6756 | __mark_reg64_unbounded(dst_reg); | |
6757 | __update_reg32_bounds(dst_reg); | |
6758 | } | |
6759 | ||
07cd2631 JF |
6760 | static void scalar_min_max_rsh(struct bpf_reg_state *dst_reg, |
6761 | struct bpf_reg_state *src_reg) | |
6762 | { | |
6763 | u64 umax_val = src_reg->umax_value; | |
6764 | u64 umin_val = src_reg->umin_value; | |
6765 | ||
6766 | /* BPF_RSH is an unsigned shift. If the value in dst_reg might | |
6767 | * be negative, then either: | |
6768 | * 1) src_reg might be zero, so the sign bit of the result is | |
6769 | * unknown, so we lose our signed bounds | |
6770 | * 2) it's known negative, thus the unsigned bounds capture the | |
6771 | * signed bounds | |
6772 | * 3) the signed bounds cross zero, so they tell us nothing | |
6773 | * about the result | |
6774 | * If the value in dst_reg is known nonnegative, then again the | |
18b24d78 | 6775 | * unsigned bounds capture the signed bounds. |
07cd2631 JF |
6776 | * Thus, in all cases it suffices to blow away our signed bounds |
6777 | * and rely on inferring new ones from the unsigned bounds and | |
6778 | * var_off of the result. | |
6779 | */ | |
6780 | dst_reg->smin_value = S64_MIN; | |
6781 | dst_reg->smax_value = S64_MAX; | |
6782 | dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val); | |
6783 | dst_reg->umin_value >>= umax_val; | |
6784 | dst_reg->umax_value >>= umin_val; | |
3f50f132 JF |
6785 | |
6786 | /* Its not easy to operate on alu32 bounds here because it depends | |
6787 | * on bits being shifted in. Take easy way out and mark unbounded | |
6788 | * so we can recalculate later from tnum. | |
6789 | */ | |
6790 | __mark_reg32_unbounded(dst_reg); | |
07cd2631 JF |
6791 | __update_reg_bounds(dst_reg); |
6792 | } | |
6793 | ||
3f50f132 JF |
6794 | static void scalar32_min_max_arsh(struct bpf_reg_state *dst_reg, |
6795 | struct bpf_reg_state *src_reg) | |
07cd2631 | 6796 | { |
3f50f132 | 6797 | u64 umin_val = src_reg->u32_min_value; |
07cd2631 JF |
6798 | |
6799 | /* Upon reaching here, src_known is true and | |
6800 | * umax_val is equal to umin_val. | |
6801 | */ | |
3f50f132 JF |
6802 | dst_reg->s32_min_value = (u32)(((s32)dst_reg->s32_min_value) >> umin_val); |
6803 | dst_reg->s32_max_value = (u32)(((s32)dst_reg->s32_max_value) >> umin_val); | |
07cd2631 | 6804 | |
3f50f132 JF |
6805 | dst_reg->var_off = tnum_arshift(tnum_subreg(dst_reg->var_off), umin_val, 32); |
6806 | ||
6807 | /* blow away the dst_reg umin_value/umax_value and rely on | |
6808 | * dst_reg var_off to refine the result. | |
6809 | */ | |
6810 | dst_reg->u32_min_value = 0; | |
6811 | dst_reg->u32_max_value = U32_MAX; | |
6812 | ||
6813 | __mark_reg64_unbounded(dst_reg); | |
6814 | __update_reg32_bounds(dst_reg); | |
6815 | } | |
6816 | ||
6817 | static void scalar_min_max_arsh(struct bpf_reg_state *dst_reg, | |
6818 | struct bpf_reg_state *src_reg) | |
6819 | { | |
6820 | u64 umin_val = src_reg->umin_value; | |
6821 | ||
6822 | /* Upon reaching here, src_known is true and umax_val is equal | |
6823 | * to umin_val. | |
6824 | */ | |
6825 | dst_reg->smin_value >>= umin_val; | |
6826 | dst_reg->smax_value >>= umin_val; | |
6827 | ||
6828 | dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val, 64); | |
07cd2631 JF |
6829 | |
6830 | /* blow away the dst_reg umin_value/umax_value and rely on | |
6831 | * dst_reg var_off to refine the result. | |
6832 | */ | |
6833 | dst_reg->umin_value = 0; | |
6834 | dst_reg->umax_value = U64_MAX; | |
3f50f132 JF |
6835 | |
6836 | /* Its not easy to operate on alu32 bounds here because it depends | |
6837 | * on bits being shifted in from upper 32-bits. Take easy way out | |
6838 | * and mark unbounded so we can recalculate later from tnum. | |
6839 | */ | |
6840 | __mark_reg32_unbounded(dst_reg); | |
07cd2631 JF |
6841 | __update_reg_bounds(dst_reg); |
6842 | } | |
6843 | ||
468f6eaf JH |
6844 | /* WARNING: This function does calculations on 64-bit values, but the actual |
6845 | * execution may occur on 32-bit values. Therefore, things like bitshifts | |
6846 | * need extra checks in the 32-bit case. | |
6847 | */ | |
f1174f77 EC |
6848 | static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, |
6849 | struct bpf_insn *insn, | |
6850 | struct bpf_reg_state *dst_reg, | |
6851 | struct bpf_reg_state src_reg) | |
969bf05e | 6852 | { |
638f5b90 | 6853 | struct bpf_reg_state *regs = cur_regs(env); |
48461135 | 6854 | u8 opcode = BPF_OP(insn->code); |
b0b3fb67 | 6855 | bool src_known; |
b03c9f9f EC |
6856 | s64 smin_val, smax_val; |
6857 | u64 umin_val, umax_val; | |
3f50f132 JF |
6858 | s32 s32_min_val, s32_max_val; |
6859 | u32 u32_min_val, u32_max_val; | |
468f6eaf | 6860 | u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32; |
d3bd7413 DB |
6861 | u32 dst = insn->dst_reg; |
6862 | int ret; | |
3f50f132 | 6863 | bool alu32 = (BPF_CLASS(insn->code) != BPF_ALU64); |
b799207e | 6864 | |
b03c9f9f EC |
6865 | smin_val = src_reg.smin_value; |
6866 | smax_val = src_reg.smax_value; | |
6867 | umin_val = src_reg.umin_value; | |
6868 | umax_val = src_reg.umax_value; | |
f23cc643 | 6869 | |
3f50f132 JF |
6870 | s32_min_val = src_reg.s32_min_value; |
6871 | s32_max_val = src_reg.s32_max_value; | |
6872 | u32_min_val = src_reg.u32_min_value; | |
6873 | u32_max_val = src_reg.u32_max_value; | |
6874 | ||
6875 | if (alu32) { | |
6876 | src_known = tnum_subreg_is_const(src_reg.var_off); | |
3f50f132 JF |
6877 | if ((src_known && |
6878 | (s32_min_val != s32_max_val || u32_min_val != u32_max_val)) || | |
6879 | s32_min_val > s32_max_val || u32_min_val > u32_max_val) { | |
6880 | /* Taint dst register if offset had invalid bounds | |
6881 | * derived from e.g. dead branches. | |
6882 | */ | |
6883 | __mark_reg_unknown(env, dst_reg); | |
6884 | return 0; | |
6885 | } | |
6886 | } else { | |
6887 | src_known = tnum_is_const(src_reg.var_off); | |
3f50f132 JF |
6888 | if ((src_known && |
6889 | (smin_val != smax_val || umin_val != umax_val)) || | |
6890 | smin_val > smax_val || umin_val > umax_val) { | |
6891 | /* Taint dst register if offset had invalid bounds | |
6892 | * derived from e.g. dead branches. | |
6893 | */ | |
6894 | __mark_reg_unknown(env, dst_reg); | |
6895 | return 0; | |
6896 | } | |
6f16101e DB |
6897 | } |
6898 | ||
bb7f0f98 AS |
6899 | if (!src_known && |
6900 | opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) { | |
f54c7898 | 6901 | __mark_reg_unknown(env, dst_reg); |
bb7f0f98 AS |
6902 | return 0; |
6903 | } | |
6904 | ||
3f50f132 JF |
6905 | /* Calculate sign/unsigned bounds and tnum for alu32 and alu64 bit ops. |
6906 | * There are two classes of instructions: The first class we track both | |
6907 | * alu32 and alu64 sign/unsigned bounds independently this provides the | |
6908 | * greatest amount of precision when alu operations are mixed with jmp32 | |
6909 | * operations. These operations are BPF_ADD, BPF_SUB, BPF_MUL, BPF_ADD, | |
6910 | * and BPF_OR. This is possible because these ops have fairly easy to | |
6911 | * understand and calculate behavior in both 32-bit and 64-bit alu ops. | |
6912 | * See alu32 verifier tests for examples. The second class of | |
6913 | * operations, BPF_LSH, BPF_RSH, and BPF_ARSH, however are not so easy | |
6914 | * with regards to tracking sign/unsigned bounds because the bits may | |
6915 | * cross subreg boundaries in the alu64 case. When this happens we mark | |
6916 | * the reg unbounded in the subreg bound space and use the resulting | |
6917 | * tnum to calculate an approximation of the sign/unsigned bounds. | |
6918 | */ | |
48461135 JB |
6919 | switch (opcode) { |
6920 | case BPF_ADD: | |
d3bd7413 DB |
6921 | ret = sanitize_val_alu(env, insn); |
6922 | if (ret < 0) { | |
6923 | verbose(env, "R%d tried to add from different pointers or scalars\n", dst); | |
6924 | return ret; | |
6925 | } | |
3f50f132 | 6926 | scalar32_min_max_add(dst_reg, &src_reg); |
07cd2631 | 6927 | scalar_min_max_add(dst_reg, &src_reg); |
3f50f132 | 6928 | dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off); |
48461135 JB |
6929 | break; |
6930 | case BPF_SUB: | |
d3bd7413 DB |
6931 | ret = sanitize_val_alu(env, insn); |
6932 | if (ret < 0) { | |
6933 | verbose(env, "R%d tried to sub from different pointers or scalars\n", dst); | |
6934 | return ret; | |
6935 | } | |
3f50f132 | 6936 | scalar32_min_max_sub(dst_reg, &src_reg); |
07cd2631 | 6937 | scalar_min_max_sub(dst_reg, &src_reg); |
3f50f132 | 6938 | dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off); |
48461135 JB |
6939 | break; |
6940 | case BPF_MUL: | |
3f50f132 JF |
6941 | dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off); |
6942 | scalar32_min_max_mul(dst_reg, &src_reg); | |
07cd2631 | 6943 | scalar_min_max_mul(dst_reg, &src_reg); |
48461135 JB |
6944 | break; |
6945 | case BPF_AND: | |
3f50f132 JF |
6946 | dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg.var_off); |
6947 | scalar32_min_max_and(dst_reg, &src_reg); | |
07cd2631 | 6948 | scalar_min_max_and(dst_reg, &src_reg); |
f1174f77 EC |
6949 | break; |
6950 | case BPF_OR: | |
3f50f132 JF |
6951 | dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg.var_off); |
6952 | scalar32_min_max_or(dst_reg, &src_reg); | |
07cd2631 | 6953 | scalar_min_max_or(dst_reg, &src_reg); |
48461135 | 6954 | break; |
2921c90d YS |
6955 | case BPF_XOR: |
6956 | dst_reg->var_off = tnum_xor(dst_reg->var_off, src_reg.var_off); | |
6957 | scalar32_min_max_xor(dst_reg, &src_reg); | |
6958 | scalar_min_max_xor(dst_reg, &src_reg); | |
6959 | break; | |
48461135 | 6960 | case BPF_LSH: |
468f6eaf JH |
6961 | if (umax_val >= insn_bitness) { |
6962 | /* Shifts greater than 31 or 63 are undefined. | |
6963 | * This includes shifts by a negative number. | |
b03c9f9f | 6964 | */ |
61bd5218 | 6965 | mark_reg_unknown(env, regs, insn->dst_reg); |
f1174f77 EC |
6966 | break; |
6967 | } | |
3f50f132 JF |
6968 | if (alu32) |
6969 | scalar32_min_max_lsh(dst_reg, &src_reg); | |
6970 | else | |
6971 | scalar_min_max_lsh(dst_reg, &src_reg); | |
48461135 JB |
6972 | break; |
6973 | case BPF_RSH: | |
468f6eaf JH |
6974 | if (umax_val >= insn_bitness) { |
6975 | /* Shifts greater than 31 or 63 are undefined. | |
6976 | * This includes shifts by a negative number. | |
b03c9f9f | 6977 | */ |
61bd5218 | 6978 | mark_reg_unknown(env, regs, insn->dst_reg); |
f1174f77 EC |
6979 | break; |
6980 | } | |
3f50f132 JF |
6981 | if (alu32) |
6982 | scalar32_min_max_rsh(dst_reg, &src_reg); | |
6983 | else | |
6984 | scalar_min_max_rsh(dst_reg, &src_reg); | |
48461135 | 6985 | break; |
9cbe1f5a YS |
6986 | case BPF_ARSH: |
6987 | if (umax_val >= insn_bitness) { | |
6988 | /* Shifts greater than 31 or 63 are undefined. | |
6989 | * This includes shifts by a negative number. | |
6990 | */ | |
6991 | mark_reg_unknown(env, regs, insn->dst_reg); | |
6992 | break; | |
6993 | } | |
3f50f132 JF |
6994 | if (alu32) |
6995 | scalar32_min_max_arsh(dst_reg, &src_reg); | |
6996 | else | |
6997 | scalar_min_max_arsh(dst_reg, &src_reg); | |
9cbe1f5a | 6998 | break; |
48461135 | 6999 | default: |
61bd5218 | 7000 | mark_reg_unknown(env, regs, insn->dst_reg); |
48461135 JB |
7001 | break; |
7002 | } | |
7003 | ||
3f50f132 JF |
7004 | /* ALU32 ops are zero extended into 64bit register */ |
7005 | if (alu32) | |
7006 | zext_32_to_64(dst_reg); | |
468f6eaf | 7007 | |
294f2fc6 | 7008 | __update_reg_bounds(dst_reg); |
b03c9f9f EC |
7009 | __reg_deduce_bounds(dst_reg); |
7010 | __reg_bound_offset(dst_reg); | |
f1174f77 EC |
7011 | return 0; |
7012 | } | |
7013 | ||
7014 | /* Handles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max | |
7015 | * and var_off. | |
7016 | */ | |
7017 | static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, | |
7018 | struct bpf_insn *insn) | |
7019 | { | |
f4d7e40a AS |
7020 | struct bpf_verifier_state *vstate = env->cur_state; |
7021 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
7022 | struct bpf_reg_state *regs = state->regs, *dst_reg, *src_reg; | |
f1174f77 EC |
7023 | struct bpf_reg_state *ptr_reg = NULL, off_reg = {0}; |
7024 | u8 opcode = BPF_OP(insn->code); | |
b5dc0163 | 7025 | int err; |
f1174f77 EC |
7026 | |
7027 | dst_reg = ®s[insn->dst_reg]; | |
f1174f77 EC |
7028 | src_reg = NULL; |
7029 | if (dst_reg->type != SCALAR_VALUE) | |
7030 | ptr_reg = dst_reg; | |
75748837 AS |
7031 | else |
7032 | /* Make sure ID is cleared otherwise dst_reg min/max could be | |
7033 | * incorrectly propagated into other registers by find_equal_scalars() | |
7034 | */ | |
7035 | dst_reg->id = 0; | |
f1174f77 EC |
7036 | if (BPF_SRC(insn->code) == BPF_X) { |
7037 | src_reg = ®s[insn->src_reg]; | |
f1174f77 EC |
7038 | if (src_reg->type != SCALAR_VALUE) { |
7039 | if (dst_reg->type != SCALAR_VALUE) { | |
7040 | /* Combining two pointers by any ALU op yields | |
82abbf8d AS |
7041 | * an arbitrary scalar. Disallow all math except |
7042 | * pointer subtraction | |
f1174f77 | 7043 | */ |
dd066823 | 7044 | if (opcode == BPF_SUB && env->allow_ptr_leaks) { |
82abbf8d AS |
7045 | mark_reg_unknown(env, regs, insn->dst_reg); |
7046 | return 0; | |
f1174f77 | 7047 | } |
82abbf8d AS |
7048 | verbose(env, "R%d pointer %s pointer prohibited\n", |
7049 | insn->dst_reg, | |
7050 | bpf_alu_string[opcode >> 4]); | |
7051 | return -EACCES; | |
f1174f77 EC |
7052 | } else { |
7053 | /* scalar += pointer | |
7054 | * This is legal, but we have to reverse our | |
7055 | * src/dest handling in computing the range | |
7056 | */ | |
b5dc0163 AS |
7057 | err = mark_chain_precision(env, insn->dst_reg); |
7058 | if (err) | |
7059 | return err; | |
82abbf8d AS |
7060 | return adjust_ptr_min_max_vals(env, insn, |
7061 | src_reg, dst_reg); | |
f1174f77 EC |
7062 | } |
7063 | } else if (ptr_reg) { | |
7064 | /* pointer += scalar */ | |
b5dc0163 AS |
7065 | err = mark_chain_precision(env, insn->src_reg); |
7066 | if (err) | |
7067 | return err; | |
82abbf8d AS |
7068 | return adjust_ptr_min_max_vals(env, insn, |
7069 | dst_reg, src_reg); | |
f1174f77 EC |
7070 | } |
7071 | } else { | |
7072 | /* Pretend the src is a reg with a known value, since we only | |
7073 | * need to be able to read from this state. | |
7074 | */ | |
7075 | off_reg.type = SCALAR_VALUE; | |
b03c9f9f | 7076 | __mark_reg_known(&off_reg, insn->imm); |
f1174f77 | 7077 | src_reg = &off_reg; |
82abbf8d AS |
7078 | if (ptr_reg) /* pointer += K */ |
7079 | return adjust_ptr_min_max_vals(env, insn, | |
7080 | ptr_reg, src_reg); | |
f1174f77 EC |
7081 | } |
7082 | ||
7083 | /* Got here implies adding two SCALAR_VALUEs */ | |
7084 | if (WARN_ON_ONCE(ptr_reg)) { | |
f4d7e40a | 7085 | print_verifier_state(env, state); |
61bd5218 | 7086 | verbose(env, "verifier internal error: unexpected ptr_reg\n"); |
f1174f77 EC |
7087 | return -EINVAL; |
7088 | } | |
7089 | if (WARN_ON(!src_reg)) { | |
f4d7e40a | 7090 | print_verifier_state(env, state); |
61bd5218 | 7091 | verbose(env, "verifier internal error: no src_reg\n"); |
f1174f77 EC |
7092 | return -EINVAL; |
7093 | } | |
7094 | return adjust_scalar_min_max_vals(env, insn, dst_reg, *src_reg); | |
48461135 JB |
7095 | } |
7096 | ||
17a52670 | 7097 | /* check validity of 32-bit and 64-bit arithmetic operations */ |
58e2af8b | 7098 | static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) |
17a52670 | 7099 | { |
638f5b90 | 7100 | struct bpf_reg_state *regs = cur_regs(env); |
17a52670 AS |
7101 | u8 opcode = BPF_OP(insn->code); |
7102 | int err; | |
7103 | ||
7104 | if (opcode == BPF_END || opcode == BPF_NEG) { | |
7105 | if (opcode == BPF_NEG) { | |
7106 | if (BPF_SRC(insn->code) != 0 || | |
7107 | insn->src_reg != BPF_REG_0 || | |
7108 | insn->off != 0 || insn->imm != 0) { | |
61bd5218 | 7109 | verbose(env, "BPF_NEG uses reserved fields\n"); |
17a52670 AS |
7110 | return -EINVAL; |
7111 | } | |
7112 | } else { | |
7113 | if (insn->src_reg != BPF_REG_0 || insn->off != 0 || | |
e67b8a68 EC |
7114 | (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) || |
7115 | BPF_CLASS(insn->code) == BPF_ALU64) { | |
61bd5218 | 7116 | verbose(env, "BPF_END uses reserved fields\n"); |
17a52670 AS |
7117 | return -EINVAL; |
7118 | } | |
7119 | } | |
7120 | ||
7121 | /* check src operand */ | |
dc503a8a | 7122 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
7123 | if (err) |
7124 | return err; | |
7125 | ||
1be7f75d | 7126 | if (is_pointer_value(env, insn->dst_reg)) { |
61bd5218 | 7127 | verbose(env, "R%d pointer arithmetic prohibited\n", |
1be7f75d AS |
7128 | insn->dst_reg); |
7129 | return -EACCES; | |
7130 | } | |
7131 | ||
17a52670 | 7132 | /* check dest operand */ |
dc503a8a | 7133 | err = check_reg_arg(env, insn->dst_reg, DST_OP); |
17a52670 AS |
7134 | if (err) |
7135 | return err; | |
7136 | ||
7137 | } else if (opcode == BPF_MOV) { | |
7138 | ||
7139 | if (BPF_SRC(insn->code) == BPF_X) { | |
7140 | if (insn->imm != 0 || insn->off != 0) { | |
61bd5218 | 7141 | verbose(env, "BPF_MOV uses reserved fields\n"); |
17a52670 AS |
7142 | return -EINVAL; |
7143 | } | |
7144 | ||
7145 | /* check src operand */ | |
dc503a8a | 7146 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
7147 | if (err) |
7148 | return err; | |
7149 | } else { | |
7150 | if (insn->src_reg != BPF_REG_0 || insn->off != 0) { | |
61bd5218 | 7151 | verbose(env, "BPF_MOV uses reserved fields\n"); |
17a52670 AS |
7152 | return -EINVAL; |
7153 | } | |
7154 | } | |
7155 | ||
fbeb1603 AF |
7156 | /* check dest operand, mark as required later */ |
7157 | err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); | |
17a52670 AS |
7158 | if (err) |
7159 | return err; | |
7160 | ||
7161 | if (BPF_SRC(insn->code) == BPF_X) { | |
e434b8cd JW |
7162 | struct bpf_reg_state *src_reg = regs + insn->src_reg; |
7163 | struct bpf_reg_state *dst_reg = regs + insn->dst_reg; | |
7164 | ||
17a52670 AS |
7165 | if (BPF_CLASS(insn->code) == BPF_ALU64) { |
7166 | /* case: R1 = R2 | |
7167 | * copy register state to dest reg | |
7168 | */ | |
75748837 AS |
7169 | if (src_reg->type == SCALAR_VALUE && !src_reg->id) |
7170 | /* Assign src and dst registers the same ID | |
7171 | * that will be used by find_equal_scalars() | |
7172 | * to propagate min/max range. | |
7173 | */ | |
7174 | src_reg->id = ++env->id_gen; | |
e434b8cd JW |
7175 | *dst_reg = *src_reg; |
7176 | dst_reg->live |= REG_LIVE_WRITTEN; | |
5327ed3d | 7177 | dst_reg->subreg_def = DEF_NOT_SUBREG; |
17a52670 | 7178 | } else { |
f1174f77 | 7179 | /* R1 = (u32) R2 */ |
1be7f75d | 7180 | if (is_pointer_value(env, insn->src_reg)) { |
61bd5218 JK |
7181 | verbose(env, |
7182 | "R%d partial copy of pointer\n", | |
1be7f75d AS |
7183 | insn->src_reg); |
7184 | return -EACCES; | |
e434b8cd JW |
7185 | } else if (src_reg->type == SCALAR_VALUE) { |
7186 | *dst_reg = *src_reg; | |
75748837 AS |
7187 | /* Make sure ID is cleared otherwise |
7188 | * dst_reg min/max could be incorrectly | |
7189 | * propagated into src_reg by find_equal_scalars() | |
7190 | */ | |
7191 | dst_reg->id = 0; | |
e434b8cd | 7192 | dst_reg->live |= REG_LIVE_WRITTEN; |
5327ed3d | 7193 | dst_reg->subreg_def = env->insn_idx + 1; |
e434b8cd JW |
7194 | } else { |
7195 | mark_reg_unknown(env, regs, | |
7196 | insn->dst_reg); | |
1be7f75d | 7197 | } |
3f50f132 | 7198 | zext_32_to_64(dst_reg); |
17a52670 AS |
7199 | } |
7200 | } else { | |
7201 | /* case: R = imm | |
7202 | * remember the value we stored into this reg | |
7203 | */ | |
fbeb1603 AF |
7204 | /* clear any state __mark_reg_known doesn't set */ |
7205 | mark_reg_unknown(env, regs, insn->dst_reg); | |
f1174f77 | 7206 | regs[insn->dst_reg].type = SCALAR_VALUE; |
95a762e2 JH |
7207 | if (BPF_CLASS(insn->code) == BPF_ALU64) { |
7208 | __mark_reg_known(regs + insn->dst_reg, | |
7209 | insn->imm); | |
7210 | } else { | |
7211 | __mark_reg_known(regs + insn->dst_reg, | |
7212 | (u32)insn->imm); | |
7213 | } | |
17a52670 AS |
7214 | } |
7215 | ||
7216 | } else if (opcode > BPF_END) { | |
61bd5218 | 7217 | verbose(env, "invalid BPF_ALU opcode %x\n", opcode); |
17a52670 AS |
7218 | return -EINVAL; |
7219 | ||
7220 | } else { /* all other ALU ops: and, sub, xor, add, ... */ | |
7221 | ||
17a52670 AS |
7222 | if (BPF_SRC(insn->code) == BPF_X) { |
7223 | if (insn->imm != 0 || insn->off != 0) { | |
61bd5218 | 7224 | verbose(env, "BPF_ALU uses reserved fields\n"); |
17a52670 AS |
7225 | return -EINVAL; |
7226 | } | |
7227 | /* check src1 operand */ | |
dc503a8a | 7228 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
7229 | if (err) |
7230 | return err; | |
7231 | } else { | |
7232 | if (insn->src_reg != BPF_REG_0 || insn->off != 0) { | |
61bd5218 | 7233 | verbose(env, "BPF_ALU uses reserved fields\n"); |
17a52670 AS |
7234 | return -EINVAL; |
7235 | } | |
7236 | } | |
7237 | ||
7238 | /* check src2 operand */ | |
dc503a8a | 7239 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
7240 | if (err) |
7241 | return err; | |
7242 | ||
7243 | if ((opcode == BPF_MOD || opcode == BPF_DIV) && | |
7244 | BPF_SRC(insn->code) == BPF_K && insn->imm == 0) { | |
61bd5218 | 7245 | verbose(env, "div by zero\n"); |
17a52670 AS |
7246 | return -EINVAL; |
7247 | } | |
7248 | ||
229394e8 RV |
7249 | if ((opcode == BPF_LSH || opcode == BPF_RSH || |
7250 | opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) { | |
7251 | int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32; | |
7252 | ||
7253 | if (insn->imm < 0 || insn->imm >= size) { | |
61bd5218 | 7254 | verbose(env, "invalid shift %d\n", insn->imm); |
229394e8 RV |
7255 | return -EINVAL; |
7256 | } | |
7257 | } | |
7258 | ||
1a0dc1ac | 7259 | /* check dest operand */ |
dc503a8a | 7260 | err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); |
1a0dc1ac AS |
7261 | if (err) |
7262 | return err; | |
7263 | ||
f1174f77 | 7264 | return adjust_reg_min_max_vals(env, insn); |
17a52670 AS |
7265 | } |
7266 | ||
7267 | return 0; | |
7268 | } | |
7269 | ||
c6a9efa1 PC |
7270 | static void __find_good_pkt_pointers(struct bpf_func_state *state, |
7271 | struct bpf_reg_state *dst_reg, | |
6d94e741 | 7272 | enum bpf_reg_type type, int new_range) |
c6a9efa1 PC |
7273 | { |
7274 | struct bpf_reg_state *reg; | |
7275 | int i; | |
7276 | ||
7277 | for (i = 0; i < MAX_BPF_REG; i++) { | |
7278 | reg = &state->regs[i]; | |
7279 | if (reg->type == type && reg->id == dst_reg->id) | |
7280 | /* keep the maximum range already checked */ | |
7281 | reg->range = max(reg->range, new_range); | |
7282 | } | |
7283 | ||
7284 | bpf_for_each_spilled_reg(i, state, reg) { | |
7285 | if (!reg) | |
7286 | continue; | |
7287 | if (reg->type == type && reg->id == dst_reg->id) | |
7288 | reg->range = max(reg->range, new_range); | |
7289 | } | |
7290 | } | |
7291 | ||
f4d7e40a | 7292 | static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, |
de8f3a83 | 7293 | struct bpf_reg_state *dst_reg, |
f8ddadc4 | 7294 | enum bpf_reg_type type, |
fb2a311a | 7295 | bool range_right_open) |
969bf05e | 7296 | { |
6d94e741 | 7297 | int new_range, i; |
2d2be8ca | 7298 | |
fb2a311a DB |
7299 | if (dst_reg->off < 0 || |
7300 | (dst_reg->off == 0 && range_right_open)) | |
f1174f77 EC |
7301 | /* This doesn't give us any range */ |
7302 | return; | |
7303 | ||
b03c9f9f EC |
7304 | if (dst_reg->umax_value > MAX_PACKET_OFF || |
7305 | dst_reg->umax_value + dst_reg->off > MAX_PACKET_OFF) | |
f1174f77 EC |
7306 | /* Risk of overflow. For instance, ptr + (1<<63) may be less |
7307 | * than pkt_end, but that's because it's also less than pkt. | |
7308 | */ | |
7309 | return; | |
7310 | ||
fb2a311a DB |
7311 | new_range = dst_reg->off; |
7312 | if (range_right_open) | |
7313 | new_range--; | |
7314 | ||
7315 | /* Examples for register markings: | |
2d2be8ca | 7316 | * |
fb2a311a | 7317 | * pkt_data in dst register: |
2d2be8ca DB |
7318 | * |
7319 | * r2 = r3; | |
7320 | * r2 += 8; | |
7321 | * if (r2 > pkt_end) goto <handle exception> | |
7322 | * <access okay> | |
7323 | * | |
b4e432f1 DB |
7324 | * r2 = r3; |
7325 | * r2 += 8; | |
7326 | * if (r2 < pkt_end) goto <access okay> | |
7327 | * <handle exception> | |
7328 | * | |
2d2be8ca DB |
7329 | * Where: |
7330 | * r2 == dst_reg, pkt_end == src_reg | |
7331 | * r2=pkt(id=n,off=8,r=0) | |
7332 | * r3=pkt(id=n,off=0,r=0) | |
7333 | * | |
fb2a311a | 7334 | * pkt_data in src register: |
2d2be8ca DB |
7335 | * |
7336 | * r2 = r3; | |
7337 | * r2 += 8; | |
7338 | * if (pkt_end >= r2) goto <access okay> | |
7339 | * <handle exception> | |
7340 | * | |
b4e432f1 DB |
7341 | * r2 = r3; |
7342 | * r2 += 8; | |
7343 | * if (pkt_end <= r2) goto <handle exception> | |
7344 | * <access okay> | |
7345 | * | |
2d2be8ca DB |
7346 | * Where: |
7347 | * pkt_end == dst_reg, r2 == src_reg | |
7348 | * r2=pkt(id=n,off=8,r=0) | |
7349 | * r3=pkt(id=n,off=0,r=0) | |
7350 | * | |
7351 | * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8) | |
fb2a311a DB |
7352 | * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8) |
7353 | * and [r3, r3 + 8-1) respectively is safe to access depending on | |
7354 | * the check. | |
969bf05e | 7355 | */ |
2d2be8ca | 7356 | |
f1174f77 EC |
7357 | /* If our ids match, then we must have the same max_value. And we |
7358 | * don't care about the other reg's fixed offset, since if it's too big | |
7359 | * the range won't allow anything. | |
7360 | * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16. | |
7361 | */ | |
c6a9efa1 PC |
7362 | for (i = 0; i <= vstate->curframe; i++) |
7363 | __find_good_pkt_pointers(vstate->frame[i], dst_reg, type, | |
7364 | new_range); | |
969bf05e AS |
7365 | } |
7366 | ||
3f50f132 | 7367 | static int is_branch32_taken(struct bpf_reg_state *reg, u32 val, u8 opcode) |
4f7b3e82 | 7368 | { |
3f50f132 JF |
7369 | struct tnum subreg = tnum_subreg(reg->var_off); |
7370 | s32 sval = (s32)val; | |
a72dafaf | 7371 | |
3f50f132 JF |
7372 | switch (opcode) { |
7373 | case BPF_JEQ: | |
7374 | if (tnum_is_const(subreg)) | |
7375 | return !!tnum_equals_const(subreg, val); | |
7376 | break; | |
7377 | case BPF_JNE: | |
7378 | if (tnum_is_const(subreg)) | |
7379 | return !tnum_equals_const(subreg, val); | |
7380 | break; | |
7381 | case BPF_JSET: | |
7382 | if ((~subreg.mask & subreg.value) & val) | |
7383 | return 1; | |
7384 | if (!((subreg.mask | subreg.value) & val)) | |
7385 | return 0; | |
7386 | break; | |
7387 | case BPF_JGT: | |
7388 | if (reg->u32_min_value > val) | |
7389 | return 1; | |
7390 | else if (reg->u32_max_value <= val) | |
7391 | return 0; | |
7392 | break; | |
7393 | case BPF_JSGT: | |
7394 | if (reg->s32_min_value > sval) | |
7395 | return 1; | |
ee114dd6 | 7396 | else if (reg->s32_max_value <= sval) |
3f50f132 JF |
7397 | return 0; |
7398 | break; | |
7399 | case BPF_JLT: | |
7400 | if (reg->u32_max_value < val) | |
7401 | return 1; | |
7402 | else if (reg->u32_min_value >= val) | |
7403 | return 0; | |
7404 | break; | |
7405 | case BPF_JSLT: | |
7406 | if (reg->s32_max_value < sval) | |
7407 | return 1; | |
7408 | else if (reg->s32_min_value >= sval) | |
7409 | return 0; | |
7410 | break; | |
7411 | case BPF_JGE: | |
7412 | if (reg->u32_min_value >= val) | |
7413 | return 1; | |
7414 | else if (reg->u32_max_value < val) | |
7415 | return 0; | |
7416 | break; | |
7417 | case BPF_JSGE: | |
7418 | if (reg->s32_min_value >= sval) | |
7419 | return 1; | |
7420 | else if (reg->s32_max_value < sval) | |
7421 | return 0; | |
7422 | break; | |
7423 | case BPF_JLE: | |
7424 | if (reg->u32_max_value <= val) | |
7425 | return 1; | |
7426 | else if (reg->u32_min_value > val) | |
7427 | return 0; | |
7428 | break; | |
7429 | case BPF_JSLE: | |
7430 | if (reg->s32_max_value <= sval) | |
7431 | return 1; | |
7432 | else if (reg->s32_min_value > sval) | |
7433 | return 0; | |
7434 | break; | |
7435 | } | |
4f7b3e82 | 7436 | |
3f50f132 JF |
7437 | return -1; |
7438 | } | |
092ed096 | 7439 | |
3f50f132 JF |
7440 | |
7441 | static int is_branch64_taken(struct bpf_reg_state *reg, u64 val, u8 opcode) | |
7442 | { | |
7443 | s64 sval = (s64)val; | |
a72dafaf | 7444 | |
4f7b3e82 AS |
7445 | switch (opcode) { |
7446 | case BPF_JEQ: | |
7447 | if (tnum_is_const(reg->var_off)) | |
7448 | return !!tnum_equals_const(reg->var_off, val); | |
7449 | break; | |
7450 | case BPF_JNE: | |
7451 | if (tnum_is_const(reg->var_off)) | |
7452 | return !tnum_equals_const(reg->var_off, val); | |
7453 | break; | |
960ea056 JK |
7454 | case BPF_JSET: |
7455 | if ((~reg->var_off.mask & reg->var_off.value) & val) | |
7456 | return 1; | |
7457 | if (!((reg->var_off.mask | reg->var_off.value) & val)) | |
7458 | return 0; | |
7459 | break; | |
4f7b3e82 AS |
7460 | case BPF_JGT: |
7461 | if (reg->umin_value > val) | |
7462 | return 1; | |
7463 | else if (reg->umax_value <= val) | |
7464 | return 0; | |
7465 | break; | |
7466 | case BPF_JSGT: | |
a72dafaf | 7467 | if (reg->smin_value > sval) |
4f7b3e82 | 7468 | return 1; |
ee114dd6 | 7469 | else if (reg->smax_value <= sval) |
4f7b3e82 AS |
7470 | return 0; |
7471 | break; | |
7472 | case BPF_JLT: | |
7473 | if (reg->umax_value < val) | |
7474 | return 1; | |
7475 | else if (reg->umin_value >= val) | |
7476 | return 0; | |
7477 | break; | |
7478 | case BPF_JSLT: | |
a72dafaf | 7479 | if (reg->smax_value < sval) |
4f7b3e82 | 7480 | return 1; |
a72dafaf | 7481 | else if (reg->smin_value >= sval) |
4f7b3e82 AS |
7482 | return 0; |
7483 | break; | |
7484 | case BPF_JGE: | |
7485 | if (reg->umin_value >= val) | |
7486 | return 1; | |
7487 | else if (reg->umax_value < val) | |
7488 | return 0; | |
7489 | break; | |
7490 | case BPF_JSGE: | |
a72dafaf | 7491 | if (reg->smin_value >= sval) |
4f7b3e82 | 7492 | return 1; |
a72dafaf | 7493 | else if (reg->smax_value < sval) |
4f7b3e82 AS |
7494 | return 0; |
7495 | break; | |
7496 | case BPF_JLE: | |
7497 | if (reg->umax_value <= val) | |
7498 | return 1; | |
7499 | else if (reg->umin_value > val) | |
7500 | return 0; | |
7501 | break; | |
7502 | case BPF_JSLE: | |
a72dafaf | 7503 | if (reg->smax_value <= sval) |
4f7b3e82 | 7504 | return 1; |
a72dafaf | 7505 | else if (reg->smin_value > sval) |
4f7b3e82 AS |
7506 | return 0; |
7507 | break; | |
7508 | } | |
7509 | ||
7510 | return -1; | |
7511 | } | |
7512 | ||
3f50f132 JF |
7513 | /* compute branch direction of the expression "if (reg opcode val) goto target;" |
7514 | * and return: | |
7515 | * 1 - branch will be taken and "goto target" will be executed | |
7516 | * 0 - branch will not be taken and fall-through to next insn | |
7517 | * -1 - unknown. Example: "if (reg < 5)" is unknown when register value | |
7518 | * range [0,10] | |
604dca5e | 7519 | */ |
3f50f132 JF |
7520 | static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode, |
7521 | bool is_jmp32) | |
604dca5e | 7522 | { |
cac616db JF |
7523 | if (__is_pointer_value(false, reg)) { |
7524 | if (!reg_type_not_null(reg->type)) | |
7525 | return -1; | |
7526 | ||
7527 | /* If pointer is valid tests against zero will fail so we can | |
7528 | * use this to direct branch taken. | |
7529 | */ | |
7530 | if (val != 0) | |
7531 | return -1; | |
7532 | ||
7533 | switch (opcode) { | |
7534 | case BPF_JEQ: | |
7535 | return 0; | |
7536 | case BPF_JNE: | |
7537 | return 1; | |
7538 | default: | |
7539 | return -1; | |
7540 | } | |
7541 | } | |
604dca5e | 7542 | |
3f50f132 JF |
7543 | if (is_jmp32) |
7544 | return is_branch32_taken(reg, val, opcode); | |
7545 | return is_branch64_taken(reg, val, opcode); | |
604dca5e JH |
7546 | } |
7547 | ||
6d94e741 AS |
7548 | static int flip_opcode(u32 opcode) |
7549 | { | |
7550 | /* How can we transform "a <op> b" into "b <op> a"? */ | |
7551 | static const u8 opcode_flip[16] = { | |
7552 | /* these stay the same */ | |
7553 | [BPF_JEQ >> 4] = BPF_JEQ, | |
7554 | [BPF_JNE >> 4] = BPF_JNE, | |
7555 | [BPF_JSET >> 4] = BPF_JSET, | |
7556 | /* these swap "lesser" and "greater" (L and G in the opcodes) */ | |
7557 | [BPF_JGE >> 4] = BPF_JLE, | |
7558 | [BPF_JGT >> 4] = BPF_JLT, | |
7559 | [BPF_JLE >> 4] = BPF_JGE, | |
7560 | [BPF_JLT >> 4] = BPF_JGT, | |
7561 | [BPF_JSGE >> 4] = BPF_JSLE, | |
7562 | [BPF_JSGT >> 4] = BPF_JSLT, | |
7563 | [BPF_JSLE >> 4] = BPF_JSGE, | |
7564 | [BPF_JSLT >> 4] = BPF_JSGT | |
7565 | }; | |
7566 | return opcode_flip[opcode >> 4]; | |
7567 | } | |
7568 | ||
7569 | static int is_pkt_ptr_branch_taken(struct bpf_reg_state *dst_reg, | |
7570 | struct bpf_reg_state *src_reg, | |
7571 | u8 opcode) | |
7572 | { | |
7573 | struct bpf_reg_state *pkt; | |
7574 | ||
7575 | if (src_reg->type == PTR_TO_PACKET_END) { | |
7576 | pkt = dst_reg; | |
7577 | } else if (dst_reg->type == PTR_TO_PACKET_END) { | |
7578 | pkt = src_reg; | |
7579 | opcode = flip_opcode(opcode); | |
7580 | } else { | |
7581 | return -1; | |
7582 | } | |
7583 | ||
7584 | if (pkt->range >= 0) | |
7585 | return -1; | |
7586 | ||
7587 | switch (opcode) { | |
7588 | case BPF_JLE: | |
7589 | /* pkt <= pkt_end */ | |
7590 | fallthrough; | |
7591 | case BPF_JGT: | |
7592 | /* pkt > pkt_end */ | |
7593 | if (pkt->range == BEYOND_PKT_END) | |
7594 | /* pkt has at last one extra byte beyond pkt_end */ | |
7595 | return opcode == BPF_JGT; | |
7596 | break; | |
7597 | case BPF_JLT: | |
7598 | /* pkt < pkt_end */ | |
7599 | fallthrough; | |
7600 | case BPF_JGE: | |
7601 | /* pkt >= pkt_end */ | |
7602 | if (pkt->range == BEYOND_PKT_END || pkt->range == AT_PKT_END) | |
7603 | return opcode == BPF_JGE; | |
7604 | break; | |
7605 | } | |
7606 | return -1; | |
7607 | } | |
7608 | ||
48461135 JB |
7609 | /* Adjusts the register min/max values in the case that the dst_reg is the |
7610 | * variable register that we are working on, and src_reg is a constant or we're | |
7611 | * simply doing a BPF_K check. | |
f1174f77 | 7612 | * In JEQ/JNE cases we also adjust the var_off values. |
48461135 JB |
7613 | */ |
7614 | static void reg_set_min_max(struct bpf_reg_state *true_reg, | |
3f50f132 JF |
7615 | struct bpf_reg_state *false_reg, |
7616 | u64 val, u32 val32, | |
092ed096 | 7617 | u8 opcode, bool is_jmp32) |
48461135 | 7618 | { |
3f50f132 JF |
7619 | struct tnum false_32off = tnum_subreg(false_reg->var_off); |
7620 | struct tnum false_64off = false_reg->var_off; | |
7621 | struct tnum true_32off = tnum_subreg(true_reg->var_off); | |
7622 | struct tnum true_64off = true_reg->var_off; | |
7623 | s64 sval = (s64)val; | |
7624 | s32 sval32 = (s32)val32; | |
a72dafaf | 7625 | |
f1174f77 EC |
7626 | /* If the dst_reg is a pointer, we can't learn anything about its |
7627 | * variable offset from the compare (unless src_reg were a pointer into | |
7628 | * the same object, but we don't bother with that. | |
7629 | * Since false_reg and true_reg have the same type by construction, we | |
7630 | * only need to check one of them for pointerness. | |
7631 | */ | |
7632 | if (__is_pointer_value(false, false_reg)) | |
7633 | return; | |
4cabc5b1 | 7634 | |
48461135 JB |
7635 | switch (opcode) { |
7636 | case BPF_JEQ: | |
48461135 | 7637 | case BPF_JNE: |
a72dafaf JW |
7638 | { |
7639 | struct bpf_reg_state *reg = | |
7640 | opcode == BPF_JEQ ? true_reg : false_reg; | |
7641 | ||
e688c3db AS |
7642 | /* JEQ/JNE comparison doesn't change the register equivalence. |
7643 | * r1 = r2; | |
7644 | * if (r1 == 42) goto label; | |
7645 | * ... | |
7646 | * label: // here both r1 and r2 are known to be 42. | |
7647 | * | |
7648 | * Hence when marking register as known preserve it's ID. | |
48461135 | 7649 | */ |
3f50f132 JF |
7650 | if (is_jmp32) |
7651 | __mark_reg32_known(reg, val32); | |
7652 | else | |
e688c3db | 7653 | ___mark_reg_known(reg, val); |
48461135 | 7654 | break; |
a72dafaf | 7655 | } |
960ea056 | 7656 | case BPF_JSET: |
3f50f132 JF |
7657 | if (is_jmp32) { |
7658 | false_32off = tnum_and(false_32off, tnum_const(~val32)); | |
7659 | if (is_power_of_2(val32)) | |
7660 | true_32off = tnum_or(true_32off, | |
7661 | tnum_const(val32)); | |
7662 | } else { | |
7663 | false_64off = tnum_and(false_64off, tnum_const(~val)); | |
7664 | if (is_power_of_2(val)) | |
7665 | true_64off = tnum_or(true_64off, | |
7666 | tnum_const(val)); | |
7667 | } | |
960ea056 | 7668 | break; |
48461135 | 7669 | case BPF_JGE: |
a72dafaf JW |
7670 | case BPF_JGT: |
7671 | { | |
3f50f132 JF |
7672 | if (is_jmp32) { |
7673 | u32 false_umax = opcode == BPF_JGT ? val32 : val32 - 1; | |
7674 | u32 true_umin = opcode == BPF_JGT ? val32 + 1 : val32; | |
7675 | ||
7676 | false_reg->u32_max_value = min(false_reg->u32_max_value, | |
7677 | false_umax); | |
7678 | true_reg->u32_min_value = max(true_reg->u32_min_value, | |
7679 | true_umin); | |
7680 | } else { | |
7681 | u64 false_umax = opcode == BPF_JGT ? val : val - 1; | |
7682 | u64 true_umin = opcode == BPF_JGT ? val + 1 : val; | |
7683 | ||
7684 | false_reg->umax_value = min(false_reg->umax_value, false_umax); | |
7685 | true_reg->umin_value = max(true_reg->umin_value, true_umin); | |
7686 | } | |
b03c9f9f | 7687 | break; |
a72dafaf | 7688 | } |
48461135 | 7689 | case BPF_JSGE: |
a72dafaf JW |
7690 | case BPF_JSGT: |
7691 | { | |
3f50f132 JF |
7692 | if (is_jmp32) { |
7693 | s32 false_smax = opcode == BPF_JSGT ? sval32 : sval32 - 1; | |
7694 | s32 true_smin = opcode == BPF_JSGT ? sval32 + 1 : sval32; | |
a72dafaf | 7695 | |
3f50f132 JF |
7696 | false_reg->s32_max_value = min(false_reg->s32_max_value, false_smax); |
7697 | true_reg->s32_min_value = max(true_reg->s32_min_value, true_smin); | |
7698 | } else { | |
7699 | s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1; | |
7700 | s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval; | |
7701 | ||
7702 | false_reg->smax_value = min(false_reg->smax_value, false_smax); | |
7703 | true_reg->smin_value = max(true_reg->smin_value, true_smin); | |
7704 | } | |
48461135 | 7705 | break; |
a72dafaf | 7706 | } |
b4e432f1 | 7707 | case BPF_JLE: |
a72dafaf JW |
7708 | case BPF_JLT: |
7709 | { | |
3f50f132 JF |
7710 | if (is_jmp32) { |
7711 | u32 false_umin = opcode == BPF_JLT ? val32 : val32 + 1; | |
7712 | u32 true_umax = opcode == BPF_JLT ? val32 - 1 : val32; | |
7713 | ||
7714 | false_reg->u32_min_value = max(false_reg->u32_min_value, | |
7715 | false_umin); | |
7716 | true_reg->u32_max_value = min(true_reg->u32_max_value, | |
7717 | true_umax); | |
7718 | } else { | |
7719 | u64 false_umin = opcode == BPF_JLT ? val : val + 1; | |
7720 | u64 true_umax = opcode == BPF_JLT ? val - 1 : val; | |
7721 | ||
7722 | false_reg->umin_value = max(false_reg->umin_value, false_umin); | |
7723 | true_reg->umax_value = min(true_reg->umax_value, true_umax); | |
7724 | } | |
b4e432f1 | 7725 | break; |
a72dafaf | 7726 | } |
b4e432f1 | 7727 | case BPF_JSLE: |
a72dafaf JW |
7728 | case BPF_JSLT: |
7729 | { | |
3f50f132 JF |
7730 | if (is_jmp32) { |
7731 | s32 false_smin = opcode == BPF_JSLT ? sval32 : sval32 + 1; | |
7732 | s32 true_smax = opcode == BPF_JSLT ? sval32 - 1 : sval32; | |
a72dafaf | 7733 | |
3f50f132 JF |
7734 | false_reg->s32_min_value = max(false_reg->s32_min_value, false_smin); |
7735 | true_reg->s32_max_value = min(true_reg->s32_max_value, true_smax); | |
7736 | } else { | |
7737 | s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1; | |
7738 | s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval; | |
7739 | ||
7740 | false_reg->smin_value = max(false_reg->smin_value, false_smin); | |
7741 | true_reg->smax_value = min(true_reg->smax_value, true_smax); | |
7742 | } | |
b4e432f1 | 7743 | break; |
a72dafaf | 7744 | } |
48461135 | 7745 | default: |
0fc31b10 | 7746 | return; |
48461135 JB |
7747 | } |
7748 | ||
3f50f132 JF |
7749 | if (is_jmp32) { |
7750 | false_reg->var_off = tnum_or(tnum_clear_subreg(false_64off), | |
7751 | tnum_subreg(false_32off)); | |
7752 | true_reg->var_off = tnum_or(tnum_clear_subreg(true_64off), | |
7753 | tnum_subreg(true_32off)); | |
7754 | __reg_combine_32_into_64(false_reg); | |
7755 | __reg_combine_32_into_64(true_reg); | |
7756 | } else { | |
7757 | false_reg->var_off = false_64off; | |
7758 | true_reg->var_off = true_64off; | |
7759 | __reg_combine_64_into_32(false_reg); | |
7760 | __reg_combine_64_into_32(true_reg); | |
7761 | } | |
48461135 JB |
7762 | } |
7763 | ||
f1174f77 EC |
7764 | /* Same as above, but for the case that dst_reg holds a constant and src_reg is |
7765 | * the variable reg. | |
48461135 JB |
7766 | */ |
7767 | static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, | |
3f50f132 JF |
7768 | struct bpf_reg_state *false_reg, |
7769 | u64 val, u32 val32, | |
092ed096 | 7770 | u8 opcode, bool is_jmp32) |
48461135 | 7771 | { |
6d94e741 | 7772 | opcode = flip_opcode(opcode); |
0fc31b10 JH |
7773 | /* This uses zero as "not present in table"; luckily the zero opcode, |
7774 | * BPF_JA, can't get here. | |
b03c9f9f | 7775 | */ |
0fc31b10 | 7776 | if (opcode) |
3f50f132 | 7777 | reg_set_min_max(true_reg, false_reg, val, val32, opcode, is_jmp32); |
f1174f77 EC |
7778 | } |
7779 | ||
7780 | /* Regs are known to be equal, so intersect their min/max/var_off */ | |
7781 | static void __reg_combine_min_max(struct bpf_reg_state *src_reg, | |
7782 | struct bpf_reg_state *dst_reg) | |
7783 | { | |
b03c9f9f EC |
7784 | src_reg->umin_value = dst_reg->umin_value = max(src_reg->umin_value, |
7785 | dst_reg->umin_value); | |
7786 | src_reg->umax_value = dst_reg->umax_value = min(src_reg->umax_value, | |
7787 | dst_reg->umax_value); | |
7788 | src_reg->smin_value = dst_reg->smin_value = max(src_reg->smin_value, | |
7789 | dst_reg->smin_value); | |
7790 | src_reg->smax_value = dst_reg->smax_value = min(src_reg->smax_value, | |
7791 | dst_reg->smax_value); | |
f1174f77 EC |
7792 | src_reg->var_off = dst_reg->var_off = tnum_intersect(src_reg->var_off, |
7793 | dst_reg->var_off); | |
b03c9f9f EC |
7794 | /* We might have learned new bounds from the var_off. */ |
7795 | __update_reg_bounds(src_reg); | |
7796 | __update_reg_bounds(dst_reg); | |
7797 | /* We might have learned something about the sign bit. */ | |
7798 | __reg_deduce_bounds(src_reg); | |
7799 | __reg_deduce_bounds(dst_reg); | |
7800 | /* We might have learned some bits from the bounds. */ | |
7801 | __reg_bound_offset(src_reg); | |
7802 | __reg_bound_offset(dst_reg); | |
7803 | /* Intersecting with the old var_off might have improved our bounds | |
7804 | * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), | |
7805 | * then new var_off is (0; 0x7f...fc) which improves our umax. | |
7806 | */ | |
7807 | __update_reg_bounds(src_reg); | |
7808 | __update_reg_bounds(dst_reg); | |
f1174f77 EC |
7809 | } |
7810 | ||
7811 | static void reg_combine_min_max(struct bpf_reg_state *true_src, | |
7812 | struct bpf_reg_state *true_dst, | |
7813 | struct bpf_reg_state *false_src, | |
7814 | struct bpf_reg_state *false_dst, | |
7815 | u8 opcode) | |
7816 | { | |
7817 | switch (opcode) { | |
7818 | case BPF_JEQ: | |
7819 | __reg_combine_min_max(true_src, true_dst); | |
7820 | break; | |
7821 | case BPF_JNE: | |
7822 | __reg_combine_min_max(false_src, false_dst); | |
b03c9f9f | 7823 | break; |
4cabc5b1 | 7824 | } |
48461135 JB |
7825 | } |
7826 | ||
fd978bf7 JS |
7827 | static void mark_ptr_or_null_reg(struct bpf_func_state *state, |
7828 | struct bpf_reg_state *reg, u32 id, | |
840b9615 | 7829 | bool is_null) |
57a09bf0 | 7830 | { |
93c230e3 MKL |
7831 | if (reg_type_may_be_null(reg->type) && reg->id == id && |
7832 | !WARN_ON_ONCE(!reg->id)) { | |
f1174f77 EC |
7833 | /* Old offset (both fixed and variable parts) should |
7834 | * have been known-zero, because we don't allow pointer | |
7835 | * arithmetic on pointers that might be NULL. | |
7836 | */ | |
b03c9f9f EC |
7837 | if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || |
7838 | !tnum_equals_const(reg->var_off, 0) || | |
f1174f77 | 7839 | reg->off)) { |
b03c9f9f EC |
7840 | __mark_reg_known_zero(reg); |
7841 | reg->off = 0; | |
f1174f77 EC |
7842 | } |
7843 | if (is_null) { | |
7844 | reg->type = SCALAR_VALUE; | |
1b986589 MKL |
7845 | /* We don't need id and ref_obj_id from this point |
7846 | * onwards anymore, thus we should better reset it, | |
7847 | * so that state pruning has chances to take effect. | |
7848 | */ | |
7849 | reg->id = 0; | |
7850 | reg->ref_obj_id = 0; | |
4ddb7416 DB |
7851 | |
7852 | return; | |
7853 | } | |
7854 | ||
7855 | mark_ptr_not_null_reg(reg); | |
7856 | ||
7857 | if (!reg_may_point_to_spin_lock(reg)) { | |
1b986589 MKL |
7858 | /* For not-NULL ptr, reg->ref_obj_id will be reset |
7859 | * in release_reg_references(). | |
7860 | * | |
7861 | * reg->id is still used by spin_lock ptr. Other | |
7862 | * than spin_lock ptr type, reg->id can be reset. | |
fd978bf7 JS |
7863 | */ |
7864 | reg->id = 0; | |
56f668df | 7865 | } |
57a09bf0 TG |
7866 | } |
7867 | } | |
7868 | ||
c6a9efa1 PC |
7869 | static void __mark_ptr_or_null_regs(struct bpf_func_state *state, u32 id, |
7870 | bool is_null) | |
7871 | { | |
7872 | struct bpf_reg_state *reg; | |
7873 | int i; | |
7874 | ||
7875 | for (i = 0; i < MAX_BPF_REG; i++) | |
7876 | mark_ptr_or_null_reg(state, &state->regs[i], id, is_null); | |
7877 | ||
7878 | bpf_for_each_spilled_reg(i, state, reg) { | |
7879 | if (!reg) | |
7880 | continue; | |
7881 | mark_ptr_or_null_reg(state, reg, id, is_null); | |
7882 | } | |
7883 | } | |
7884 | ||
57a09bf0 TG |
7885 | /* The logic is similar to find_good_pkt_pointers(), both could eventually |
7886 | * be folded together at some point. | |
7887 | */ | |
840b9615 JS |
7888 | static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno, |
7889 | bool is_null) | |
57a09bf0 | 7890 | { |
f4d7e40a | 7891 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; |
c6a9efa1 | 7892 | struct bpf_reg_state *regs = state->regs; |
1b986589 | 7893 | u32 ref_obj_id = regs[regno].ref_obj_id; |
a08dd0da | 7894 | u32 id = regs[regno].id; |
c6a9efa1 | 7895 | int i; |
57a09bf0 | 7896 | |
1b986589 MKL |
7897 | if (ref_obj_id && ref_obj_id == id && is_null) |
7898 | /* regs[regno] is in the " == NULL" branch. | |
7899 | * No one could have freed the reference state before | |
7900 | * doing the NULL check. | |
7901 | */ | |
7902 | WARN_ON_ONCE(release_reference_state(state, id)); | |
fd978bf7 | 7903 | |
c6a9efa1 PC |
7904 | for (i = 0; i <= vstate->curframe; i++) |
7905 | __mark_ptr_or_null_regs(vstate->frame[i], id, is_null); | |
57a09bf0 TG |
7906 | } |
7907 | ||
5beca081 DB |
7908 | static bool try_match_pkt_pointers(const struct bpf_insn *insn, |
7909 | struct bpf_reg_state *dst_reg, | |
7910 | struct bpf_reg_state *src_reg, | |
7911 | struct bpf_verifier_state *this_branch, | |
7912 | struct bpf_verifier_state *other_branch) | |
7913 | { | |
7914 | if (BPF_SRC(insn->code) != BPF_X) | |
7915 | return false; | |
7916 | ||
092ed096 JW |
7917 | /* Pointers are always 64-bit. */ |
7918 | if (BPF_CLASS(insn->code) == BPF_JMP32) | |
7919 | return false; | |
7920 | ||
5beca081 DB |
7921 | switch (BPF_OP(insn->code)) { |
7922 | case BPF_JGT: | |
7923 | if ((dst_reg->type == PTR_TO_PACKET && | |
7924 | src_reg->type == PTR_TO_PACKET_END) || | |
7925 | (dst_reg->type == PTR_TO_PACKET_META && | |
7926 | reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) { | |
7927 | /* pkt_data' > pkt_end, pkt_meta' > pkt_data */ | |
7928 | find_good_pkt_pointers(this_branch, dst_reg, | |
7929 | dst_reg->type, false); | |
6d94e741 | 7930 | mark_pkt_end(other_branch, insn->dst_reg, true); |
5beca081 DB |
7931 | } else if ((dst_reg->type == PTR_TO_PACKET_END && |
7932 | src_reg->type == PTR_TO_PACKET) || | |
7933 | (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && | |
7934 | src_reg->type == PTR_TO_PACKET_META)) { | |
7935 | /* pkt_end > pkt_data', pkt_data > pkt_meta' */ | |
7936 | find_good_pkt_pointers(other_branch, src_reg, | |
7937 | src_reg->type, true); | |
6d94e741 | 7938 | mark_pkt_end(this_branch, insn->src_reg, false); |
5beca081 DB |
7939 | } else { |
7940 | return false; | |
7941 | } | |
7942 | break; | |
7943 | case BPF_JLT: | |
7944 | if ((dst_reg->type == PTR_TO_PACKET && | |
7945 | src_reg->type == PTR_TO_PACKET_END) || | |
7946 | (dst_reg->type == PTR_TO_PACKET_META && | |
7947 | reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) { | |
7948 | /* pkt_data' < pkt_end, pkt_meta' < pkt_data */ | |
7949 | find_good_pkt_pointers(other_branch, dst_reg, | |
7950 | dst_reg->type, true); | |
6d94e741 | 7951 | mark_pkt_end(this_branch, insn->dst_reg, false); |
5beca081 DB |
7952 | } else if ((dst_reg->type == PTR_TO_PACKET_END && |
7953 | src_reg->type == PTR_TO_PACKET) || | |
7954 | (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && | |
7955 | src_reg->type == PTR_TO_PACKET_META)) { | |
7956 | /* pkt_end < pkt_data', pkt_data > pkt_meta' */ | |
7957 | find_good_pkt_pointers(this_branch, src_reg, | |
7958 | src_reg->type, false); | |
6d94e741 | 7959 | mark_pkt_end(other_branch, insn->src_reg, true); |
5beca081 DB |
7960 | } else { |
7961 | return false; | |
7962 | } | |
7963 | break; | |
7964 | case BPF_JGE: | |
7965 | if ((dst_reg->type == PTR_TO_PACKET && | |
7966 | src_reg->type == PTR_TO_PACKET_END) || | |
7967 | (dst_reg->type == PTR_TO_PACKET_META && | |
7968 | reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) { | |
7969 | /* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */ | |
7970 | find_good_pkt_pointers(this_branch, dst_reg, | |
7971 | dst_reg->type, true); | |
6d94e741 | 7972 | mark_pkt_end(other_branch, insn->dst_reg, false); |
5beca081 DB |
7973 | } else if ((dst_reg->type == PTR_TO_PACKET_END && |
7974 | src_reg->type == PTR_TO_PACKET) || | |
7975 | (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && | |
7976 | src_reg->type == PTR_TO_PACKET_META)) { | |
7977 | /* pkt_end >= pkt_data', pkt_data >= pkt_meta' */ | |
7978 | find_good_pkt_pointers(other_branch, src_reg, | |
7979 | src_reg->type, false); | |
6d94e741 | 7980 | mark_pkt_end(this_branch, insn->src_reg, true); |
5beca081 DB |
7981 | } else { |
7982 | return false; | |
7983 | } | |
7984 | break; | |
7985 | case BPF_JLE: | |
7986 | if ((dst_reg->type == PTR_TO_PACKET && | |
7987 | src_reg->type == PTR_TO_PACKET_END) || | |
7988 | (dst_reg->type == PTR_TO_PACKET_META && | |
7989 | reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) { | |
7990 | /* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */ | |
7991 | find_good_pkt_pointers(other_branch, dst_reg, | |
7992 | dst_reg->type, false); | |
6d94e741 | 7993 | mark_pkt_end(this_branch, insn->dst_reg, true); |
5beca081 DB |
7994 | } else if ((dst_reg->type == PTR_TO_PACKET_END && |
7995 | src_reg->type == PTR_TO_PACKET) || | |
7996 | (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && | |
7997 | src_reg->type == PTR_TO_PACKET_META)) { | |
7998 | /* pkt_end <= pkt_data', pkt_data <= pkt_meta' */ | |
7999 | find_good_pkt_pointers(this_branch, src_reg, | |
8000 | src_reg->type, true); | |
6d94e741 | 8001 | mark_pkt_end(other_branch, insn->src_reg, false); |
5beca081 DB |
8002 | } else { |
8003 | return false; | |
8004 | } | |
8005 | break; | |
8006 | default: | |
8007 | return false; | |
8008 | } | |
8009 | ||
8010 | return true; | |
8011 | } | |
8012 | ||
75748837 AS |
8013 | static void find_equal_scalars(struct bpf_verifier_state *vstate, |
8014 | struct bpf_reg_state *known_reg) | |
8015 | { | |
8016 | struct bpf_func_state *state; | |
8017 | struct bpf_reg_state *reg; | |
8018 | int i, j; | |
8019 | ||
8020 | for (i = 0; i <= vstate->curframe; i++) { | |
8021 | state = vstate->frame[i]; | |
8022 | for (j = 0; j < MAX_BPF_REG; j++) { | |
8023 | reg = &state->regs[j]; | |
8024 | if (reg->type == SCALAR_VALUE && reg->id == known_reg->id) | |
8025 | *reg = *known_reg; | |
8026 | } | |
8027 | ||
8028 | bpf_for_each_spilled_reg(j, state, reg) { | |
8029 | if (!reg) | |
8030 | continue; | |
8031 | if (reg->type == SCALAR_VALUE && reg->id == known_reg->id) | |
8032 | *reg = *known_reg; | |
8033 | } | |
8034 | } | |
8035 | } | |
8036 | ||
58e2af8b | 8037 | static int check_cond_jmp_op(struct bpf_verifier_env *env, |
17a52670 AS |
8038 | struct bpf_insn *insn, int *insn_idx) |
8039 | { | |
f4d7e40a AS |
8040 | struct bpf_verifier_state *this_branch = env->cur_state; |
8041 | struct bpf_verifier_state *other_branch; | |
8042 | struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs; | |
fb8d251e | 8043 | struct bpf_reg_state *dst_reg, *other_branch_regs, *src_reg = NULL; |
17a52670 | 8044 | u8 opcode = BPF_OP(insn->code); |
092ed096 | 8045 | bool is_jmp32; |
fb8d251e | 8046 | int pred = -1; |
17a52670 AS |
8047 | int err; |
8048 | ||
092ed096 JW |
8049 | /* Only conditional jumps are expected to reach here. */ |
8050 | if (opcode == BPF_JA || opcode > BPF_JSLE) { | |
8051 | verbose(env, "invalid BPF_JMP/JMP32 opcode %x\n", opcode); | |
17a52670 AS |
8052 | return -EINVAL; |
8053 | } | |
8054 | ||
8055 | if (BPF_SRC(insn->code) == BPF_X) { | |
8056 | if (insn->imm != 0) { | |
092ed096 | 8057 | verbose(env, "BPF_JMP/JMP32 uses reserved fields\n"); |
17a52670 AS |
8058 | return -EINVAL; |
8059 | } | |
8060 | ||
8061 | /* check src1 operand */ | |
dc503a8a | 8062 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
8063 | if (err) |
8064 | return err; | |
1be7f75d AS |
8065 | |
8066 | if (is_pointer_value(env, insn->src_reg)) { | |
61bd5218 | 8067 | verbose(env, "R%d pointer comparison prohibited\n", |
1be7f75d AS |
8068 | insn->src_reg); |
8069 | return -EACCES; | |
8070 | } | |
fb8d251e | 8071 | src_reg = ®s[insn->src_reg]; |
17a52670 AS |
8072 | } else { |
8073 | if (insn->src_reg != BPF_REG_0) { | |
092ed096 | 8074 | verbose(env, "BPF_JMP/JMP32 uses reserved fields\n"); |
17a52670 AS |
8075 | return -EINVAL; |
8076 | } | |
8077 | } | |
8078 | ||
8079 | /* check src2 operand */ | |
dc503a8a | 8080 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
8081 | if (err) |
8082 | return err; | |
8083 | ||
1a0dc1ac | 8084 | dst_reg = ®s[insn->dst_reg]; |
092ed096 | 8085 | is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32; |
1a0dc1ac | 8086 | |
3f50f132 JF |
8087 | if (BPF_SRC(insn->code) == BPF_K) { |
8088 | pred = is_branch_taken(dst_reg, insn->imm, opcode, is_jmp32); | |
8089 | } else if (src_reg->type == SCALAR_VALUE && | |
8090 | is_jmp32 && tnum_is_const(tnum_subreg(src_reg->var_off))) { | |
8091 | pred = is_branch_taken(dst_reg, | |
8092 | tnum_subreg(src_reg->var_off).value, | |
8093 | opcode, | |
8094 | is_jmp32); | |
8095 | } else if (src_reg->type == SCALAR_VALUE && | |
8096 | !is_jmp32 && tnum_is_const(src_reg->var_off)) { | |
8097 | pred = is_branch_taken(dst_reg, | |
8098 | src_reg->var_off.value, | |
8099 | opcode, | |
8100 | is_jmp32); | |
6d94e741 AS |
8101 | } else if (reg_is_pkt_pointer_any(dst_reg) && |
8102 | reg_is_pkt_pointer_any(src_reg) && | |
8103 | !is_jmp32) { | |
8104 | pred = is_pkt_ptr_branch_taken(dst_reg, src_reg, opcode); | |
3f50f132 JF |
8105 | } |
8106 | ||
b5dc0163 | 8107 | if (pred >= 0) { |
cac616db JF |
8108 | /* If we get here with a dst_reg pointer type it is because |
8109 | * above is_branch_taken() special cased the 0 comparison. | |
8110 | */ | |
8111 | if (!__is_pointer_value(false, dst_reg)) | |
8112 | err = mark_chain_precision(env, insn->dst_reg); | |
6d94e741 AS |
8113 | if (BPF_SRC(insn->code) == BPF_X && !err && |
8114 | !__is_pointer_value(false, src_reg)) | |
b5dc0163 AS |
8115 | err = mark_chain_precision(env, insn->src_reg); |
8116 | if (err) | |
8117 | return err; | |
8118 | } | |
fb8d251e AS |
8119 | if (pred == 1) { |
8120 | /* only follow the goto, ignore fall-through */ | |
8121 | *insn_idx += insn->off; | |
8122 | return 0; | |
8123 | } else if (pred == 0) { | |
8124 | /* only follow fall-through branch, since | |
8125 | * that's where the program will go | |
8126 | */ | |
8127 | return 0; | |
17a52670 AS |
8128 | } |
8129 | ||
979d63d5 DB |
8130 | other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx, |
8131 | false); | |
17a52670 AS |
8132 | if (!other_branch) |
8133 | return -EFAULT; | |
f4d7e40a | 8134 | other_branch_regs = other_branch->frame[other_branch->curframe]->regs; |
17a52670 | 8135 | |
48461135 JB |
8136 | /* detect if we are comparing against a constant value so we can adjust |
8137 | * our min/max values for our dst register. | |
f1174f77 EC |
8138 | * this is only legit if both are scalars (or pointers to the same |
8139 | * object, I suppose, but we don't support that right now), because | |
8140 | * otherwise the different base pointers mean the offsets aren't | |
8141 | * comparable. | |
48461135 JB |
8142 | */ |
8143 | if (BPF_SRC(insn->code) == BPF_X) { | |
092ed096 | 8144 | struct bpf_reg_state *src_reg = ®s[insn->src_reg]; |
092ed096 | 8145 | |
f1174f77 | 8146 | if (dst_reg->type == SCALAR_VALUE && |
092ed096 JW |
8147 | src_reg->type == SCALAR_VALUE) { |
8148 | if (tnum_is_const(src_reg->var_off) || | |
3f50f132 JF |
8149 | (is_jmp32 && |
8150 | tnum_is_const(tnum_subreg(src_reg->var_off)))) | |
f4d7e40a | 8151 | reg_set_min_max(&other_branch_regs[insn->dst_reg], |
092ed096 | 8152 | dst_reg, |
3f50f132 JF |
8153 | src_reg->var_off.value, |
8154 | tnum_subreg(src_reg->var_off).value, | |
092ed096 JW |
8155 | opcode, is_jmp32); |
8156 | else if (tnum_is_const(dst_reg->var_off) || | |
3f50f132 JF |
8157 | (is_jmp32 && |
8158 | tnum_is_const(tnum_subreg(dst_reg->var_off)))) | |
f4d7e40a | 8159 | reg_set_min_max_inv(&other_branch_regs[insn->src_reg], |
092ed096 | 8160 | src_reg, |
3f50f132 JF |
8161 | dst_reg->var_off.value, |
8162 | tnum_subreg(dst_reg->var_off).value, | |
092ed096 JW |
8163 | opcode, is_jmp32); |
8164 | else if (!is_jmp32 && | |
8165 | (opcode == BPF_JEQ || opcode == BPF_JNE)) | |
f1174f77 | 8166 | /* Comparing for equality, we can combine knowledge */ |
f4d7e40a AS |
8167 | reg_combine_min_max(&other_branch_regs[insn->src_reg], |
8168 | &other_branch_regs[insn->dst_reg], | |
092ed096 | 8169 | src_reg, dst_reg, opcode); |
e688c3db AS |
8170 | if (src_reg->id && |
8171 | !WARN_ON_ONCE(src_reg->id != other_branch_regs[insn->src_reg].id)) { | |
75748837 AS |
8172 | find_equal_scalars(this_branch, src_reg); |
8173 | find_equal_scalars(other_branch, &other_branch_regs[insn->src_reg]); | |
8174 | } | |
8175 | ||
f1174f77 EC |
8176 | } |
8177 | } else if (dst_reg->type == SCALAR_VALUE) { | |
f4d7e40a | 8178 | reg_set_min_max(&other_branch_regs[insn->dst_reg], |
3f50f132 JF |
8179 | dst_reg, insn->imm, (u32)insn->imm, |
8180 | opcode, is_jmp32); | |
48461135 JB |
8181 | } |
8182 | ||
e688c3db AS |
8183 | if (dst_reg->type == SCALAR_VALUE && dst_reg->id && |
8184 | !WARN_ON_ONCE(dst_reg->id != other_branch_regs[insn->dst_reg].id)) { | |
75748837 AS |
8185 | find_equal_scalars(this_branch, dst_reg); |
8186 | find_equal_scalars(other_branch, &other_branch_regs[insn->dst_reg]); | |
8187 | } | |
8188 | ||
092ed096 JW |
8189 | /* detect if R == 0 where R is returned from bpf_map_lookup_elem(). |
8190 | * NOTE: these optimizations below are related with pointer comparison | |
8191 | * which will never be JMP32. | |
8192 | */ | |
8193 | if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K && | |
1a0dc1ac | 8194 | insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) && |
840b9615 JS |
8195 | reg_type_may_be_null(dst_reg->type)) { |
8196 | /* Mark all identical registers in each branch as either | |
57a09bf0 TG |
8197 | * safe or unknown depending R == 0 or R != 0 conditional. |
8198 | */ | |
840b9615 JS |
8199 | mark_ptr_or_null_regs(this_branch, insn->dst_reg, |
8200 | opcode == BPF_JNE); | |
8201 | mark_ptr_or_null_regs(other_branch, insn->dst_reg, | |
8202 | opcode == BPF_JEQ); | |
5beca081 DB |
8203 | } else if (!try_match_pkt_pointers(insn, dst_reg, ®s[insn->src_reg], |
8204 | this_branch, other_branch) && | |
8205 | is_pointer_value(env, insn->dst_reg)) { | |
61bd5218 JK |
8206 | verbose(env, "R%d pointer comparison prohibited\n", |
8207 | insn->dst_reg); | |
1be7f75d | 8208 | return -EACCES; |
17a52670 | 8209 | } |
06ee7115 | 8210 | if (env->log.level & BPF_LOG_LEVEL) |
f4d7e40a | 8211 | print_verifier_state(env, this_branch->frame[this_branch->curframe]); |
17a52670 AS |
8212 | return 0; |
8213 | } | |
8214 | ||
17a52670 | 8215 | /* verify BPF_LD_IMM64 instruction */ |
58e2af8b | 8216 | static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) |
17a52670 | 8217 | { |
d8eca5bb | 8218 | struct bpf_insn_aux_data *aux = cur_aux(env); |
638f5b90 | 8219 | struct bpf_reg_state *regs = cur_regs(env); |
4976b718 | 8220 | struct bpf_reg_state *dst_reg; |
d8eca5bb | 8221 | struct bpf_map *map; |
17a52670 AS |
8222 | int err; |
8223 | ||
8224 | if (BPF_SIZE(insn->code) != BPF_DW) { | |
61bd5218 | 8225 | verbose(env, "invalid BPF_LD_IMM insn\n"); |
17a52670 AS |
8226 | return -EINVAL; |
8227 | } | |
8228 | if (insn->off != 0) { | |
61bd5218 | 8229 | verbose(env, "BPF_LD_IMM64 uses reserved fields\n"); |
17a52670 AS |
8230 | return -EINVAL; |
8231 | } | |
8232 | ||
dc503a8a | 8233 | err = check_reg_arg(env, insn->dst_reg, DST_OP); |
17a52670 AS |
8234 | if (err) |
8235 | return err; | |
8236 | ||
4976b718 | 8237 | dst_reg = ®s[insn->dst_reg]; |
6b173873 | 8238 | if (insn->src_reg == 0) { |
6b173873 JK |
8239 | u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; |
8240 | ||
4976b718 | 8241 | dst_reg->type = SCALAR_VALUE; |
b03c9f9f | 8242 | __mark_reg_known(®s[insn->dst_reg], imm); |
17a52670 | 8243 | return 0; |
6b173873 | 8244 | } |
17a52670 | 8245 | |
4976b718 HL |
8246 | if (insn->src_reg == BPF_PSEUDO_BTF_ID) { |
8247 | mark_reg_known_zero(env, regs, insn->dst_reg); | |
8248 | ||
8249 | dst_reg->type = aux->btf_var.reg_type; | |
8250 | switch (dst_reg->type) { | |
8251 | case PTR_TO_MEM: | |
8252 | dst_reg->mem_size = aux->btf_var.mem_size; | |
8253 | break; | |
8254 | case PTR_TO_BTF_ID: | |
eaa6bcb7 | 8255 | case PTR_TO_PERCPU_BTF_ID: |
22dc4a0f | 8256 | dst_reg->btf = aux->btf_var.btf; |
4976b718 HL |
8257 | dst_reg->btf_id = aux->btf_var.btf_id; |
8258 | break; | |
8259 | default: | |
8260 | verbose(env, "bpf verifier is misconfigured\n"); | |
8261 | return -EFAULT; | |
8262 | } | |
8263 | return 0; | |
8264 | } | |
8265 | ||
d8eca5bb DB |
8266 | map = env->used_maps[aux->map_index]; |
8267 | mark_reg_known_zero(env, regs, insn->dst_reg); | |
4976b718 | 8268 | dst_reg->map_ptr = map; |
d8eca5bb DB |
8269 | |
8270 | if (insn->src_reg == BPF_PSEUDO_MAP_VALUE) { | |
4976b718 HL |
8271 | dst_reg->type = PTR_TO_MAP_VALUE; |
8272 | dst_reg->off = aux->map_off; | |
d8eca5bb | 8273 | if (map_value_has_spin_lock(map)) |
4976b718 | 8274 | dst_reg->id = ++env->id_gen; |
d8eca5bb | 8275 | } else if (insn->src_reg == BPF_PSEUDO_MAP_FD) { |
4976b718 | 8276 | dst_reg->type = CONST_PTR_TO_MAP; |
d8eca5bb DB |
8277 | } else { |
8278 | verbose(env, "bpf verifier is misconfigured\n"); | |
8279 | return -EINVAL; | |
8280 | } | |
17a52670 | 8281 | |
17a52670 AS |
8282 | return 0; |
8283 | } | |
8284 | ||
96be4325 DB |
8285 | static bool may_access_skb(enum bpf_prog_type type) |
8286 | { | |
8287 | switch (type) { | |
8288 | case BPF_PROG_TYPE_SOCKET_FILTER: | |
8289 | case BPF_PROG_TYPE_SCHED_CLS: | |
94caee8c | 8290 | case BPF_PROG_TYPE_SCHED_ACT: |
96be4325 DB |
8291 | return true; |
8292 | default: | |
8293 | return false; | |
8294 | } | |
8295 | } | |
8296 | ||
ddd872bc AS |
8297 | /* verify safety of LD_ABS|LD_IND instructions: |
8298 | * - they can only appear in the programs where ctx == skb | |
8299 | * - since they are wrappers of function calls, they scratch R1-R5 registers, | |
8300 | * preserve R6-R9, and store return value into R0 | |
8301 | * | |
8302 | * Implicit input: | |
8303 | * ctx == skb == R6 == CTX | |
8304 | * | |
8305 | * Explicit input: | |
8306 | * SRC == any register | |
8307 | * IMM == 32-bit immediate | |
8308 | * | |
8309 | * Output: | |
8310 | * R0 - 8/16/32-bit skb data converted to cpu endianness | |
8311 | */ | |
58e2af8b | 8312 | static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) |
ddd872bc | 8313 | { |
638f5b90 | 8314 | struct bpf_reg_state *regs = cur_regs(env); |
6d4f151a | 8315 | static const int ctx_reg = BPF_REG_6; |
ddd872bc | 8316 | u8 mode = BPF_MODE(insn->code); |
ddd872bc AS |
8317 | int i, err; |
8318 | ||
7e40781c | 8319 | if (!may_access_skb(resolve_prog_type(env->prog))) { |
61bd5218 | 8320 | verbose(env, "BPF_LD_[ABS|IND] instructions not allowed for this program type\n"); |
ddd872bc AS |
8321 | return -EINVAL; |
8322 | } | |
8323 | ||
e0cea7ce DB |
8324 | if (!env->ops->gen_ld_abs) { |
8325 | verbose(env, "bpf verifier is misconfigured\n"); | |
8326 | return -EINVAL; | |
8327 | } | |
8328 | ||
ddd872bc | 8329 | if (insn->dst_reg != BPF_REG_0 || insn->off != 0 || |
d82bccc6 | 8330 | BPF_SIZE(insn->code) == BPF_DW || |
ddd872bc | 8331 | (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) { |
61bd5218 | 8332 | verbose(env, "BPF_LD_[ABS|IND] uses reserved fields\n"); |
ddd872bc AS |
8333 | return -EINVAL; |
8334 | } | |
8335 | ||
8336 | /* check whether implicit source operand (register R6) is readable */ | |
6d4f151a | 8337 | err = check_reg_arg(env, ctx_reg, SRC_OP); |
ddd872bc AS |
8338 | if (err) |
8339 | return err; | |
8340 | ||
fd978bf7 JS |
8341 | /* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as |
8342 | * gen_ld_abs() may terminate the program at runtime, leading to | |
8343 | * reference leak. | |
8344 | */ | |
8345 | err = check_reference_leak(env); | |
8346 | if (err) { | |
8347 | verbose(env, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n"); | |
8348 | return err; | |
8349 | } | |
8350 | ||
d83525ca AS |
8351 | if (env->cur_state->active_spin_lock) { |
8352 | verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n"); | |
8353 | return -EINVAL; | |
8354 | } | |
8355 | ||
6d4f151a | 8356 | if (regs[ctx_reg].type != PTR_TO_CTX) { |
61bd5218 JK |
8357 | verbose(env, |
8358 | "at the time of BPF_LD_ABS|IND R6 != pointer to skb\n"); | |
ddd872bc AS |
8359 | return -EINVAL; |
8360 | } | |
8361 | ||
8362 | if (mode == BPF_IND) { | |
8363 | /* check explicit source operand */ | |
dc503a8a | 8364 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
ddd872bc AS |
8365 | if (err) |
8366 | return err; | |
8367 | } | |
8368 | ||
6d4f151a DB |
8369 | err = check_ctx_reg(env, ®s[ctx_reg], ctx_reg); |
8370 | if (err < 0) | |
8371 | return err; | |
8372 | ||
ddd872bc | 8373 | /* reset caller saved regs to unreadable */ |
dc503a8a | 8374 | for (i = 0; i < CALLER_SAVED_REGS; i++) { |
61bd5218 | 8375 | mark_reg_not_init(env, regs, caller_saved[i]); |
dc503a8a EC |
8376 | check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK); |
8377 | } | |
ddd872bc AS |
8378 | |
8379 | /* mark destination R0 register as readable, since it contains | |
dc503a8a EC |
8380 | * the value fetched from the packet. |
8381 | * Already marked as written above. | |
ddd872bc | 8382 | */ |
61bd5218 | 8383 | mark_reg_unknown(env, regs, BPF_REG_0); |
5327ed3d JW |
8384 | /* ld_abs load up to 32-bit skb data. */ |
8385 | regs[BPF_REG_0].subreg_def = env->insn_idx + 1; | |
ddd872bc AS |
8386 | return 0; |
8387 | } | |
8388 | ||
390ee7e2 AS |
8389 | static int check_return_code(struct bpf_verifier_env *env) |
8390 | { | |
5cf1e914 | 8391 | struct tnum enforce_attach_type_range = tnum_unknown; |
27ae7997 | 8392 | const struct bpf_prog *prog = env->prog; |
390ee7e2 AS |
8393 | struct bpf_reg_state *reg; |
8394 | struct tnum range = tnum_range(0, 1); | |
7e40781c | 8395 | enum bpf_prog_type prog_type = resolve_prog_type(env->prog); |
27ae7997 | 8396 | int err; |
f782e2c3 | 8397 | const bool is_subprog = env->cur_state->frame[0]->subprogno; |
27ae7997 | 8398 | |
9e4e01df | 8399 | /* LSM and struct_ops func-ptr's return type could be "void" */ |
f782e2c3 DB |
8400 | if (!is_subprog && |
8401 | (prog_type == BPF_PROG_TYPE_STRUCT_OPS || | |
7e40781c | 8402 | prog_type == BPF_PROG_TYPE_LSM) && |
27ae7997 MKL |
8403 | !prog->aux->attach_func_proto->type) |
8404 | return 0; | |
8405 | ||
8406 | /* eBPF calling convetion is such that R0 is used | |
8407 | * to return the value from eBPF program. | |
8408 | * Make sure that it's readable at this time | |
8409 | * of bpf_exit, which means that program wrote | |
8410 | * something into it earlier | |
8411 | */ | |
8412 | err = check_reg_arg(env, BPF_REG_0, SRC_OP); | |
8413 | if (err) | |
8414 | return err; | |
8415 | ||
8416 | if (is_pointer_value(env, BPF_REG_0)) { | |
8417 | verbose(env, "R0 leaks addr as return value\n"); | |
8418 | return -EACCES; | |
8419 | } | |
390ee7e2 | 8420 | |
f782e2c3 DB |
8421 | reg = cur_regs(env) + BPF_REG_0; |
8422 | if (is_subprog) { | |
8423 | if (reg->type != SCALAR_VALUE) { | |
8424 | verbose(env, "At subprogram exit the register R0 is not a scalar value (%s)\n", | |
8425 | reg_type_str[reg->type]); | |
8426 | return -EINVAL; | |
8427 | } | |
8428 | return 0; | |
8429 | } | |
8430 | ||
7e40781c | 8431 | switch (prog_type) { |
983695fa DB |
8432 | case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: |
8433 | if (env->prog->expected_attach_type == BPF_CGROUP_UDP4_RECVMSG || | |
1b66d253 DB |
8434 | env->prog->expected_attach_type == BPF_CGROUP_UDP6_RECVMSG || |
8435 | env->prog->expected_attach_type == BPF_CGROUP_INET4_GETPEERNAME || | |
8436 | env->prog->expected_attach_type == BPF_CGROUP_INET6_GETPEERNAME || | |
8437 | env->prog->expected_attach_type == BPF_CGROUP_INET4_GETSOCKNAME || | |
8438 | env->prog->expected_attach_type == BPF_CGROUP_INET6_GETSOCKNAME) | |
983695fa | 8439 | range = tnum_range(1, 1); |
77241217 SF |
8440 | if (env->prog->expected_attach_type == BPF_CGROUP_INET4_BIND || |
8441 | env->prog->expected_attach_type == BPF_CGROUP_INET6_BIND) | |
8442 | range = tnum_range(0, 3); | |
ed4ed404 | 8443 | break; |
390ee7e2 | 8444 | case BPF_PROG_TYPE_CGROUP_SKB: |
5cf1e914 | 8445 | if (env->prog->expected_attach_type == BPF_CGROUP_INET_EGRESS) { |
8446 | range = tnum_range(0, 3); | |
8447 | enforce_attach_type_range = tnum_range(2, 3); | |
8448 | } | |
ed4ed404 | 8449 | break; |
390ee7e2 AS |
8450 | case BPF_PROG_TYPE_CGROUP_SOCK: |
8451 | case BPF_PROG_TYPE_SOCK_OPS: | |
ebc614f6 | 8452 | case BPF_PROG_TYPE_CGROUP_DEVICE: |
7b146ceb | 8453 | case BPF_PROG_TYPE_CGROUP_SYSCTL: |
0d01da6a | 8454 | case BPF_PROG_TYPE_CGROUP_SOCKOPT: |
390ee7e2 | 8455 | break; |
15ab09bd AS |
8456 | case BPF_PROG_TYPE_RAW_TRACEPOINT: |
8457 | if (!env->prog->aux->attach_btf_id) | |
8458 | return 0; | |
8459 | range = tnum_const(0); | |
8460 | break; | |
15d83c4d | 8461 | case BPF_PROG_TYPE_TRACING: |
e92888c7 YS |
8462 | switch (env->prog->expected_attach_type) { |
8463 | case BPF_TRACE_FENTRY: | |
8464 | case BPF_TRACE_FEXIT: | |
8465 | range = tnum_const(0); | |
8466 | break; | |
8467 | case BPF_TRACE_RAW_TP: | |
8468 | case BPF_MODIFY_RETURN: | |
15d83c4d | 8469 | return 0; |
2ec0616e DB |
8470 | case BPF_TRACE_ITER: |
8471 | break; | |
e92888c7 YS |
8472 | default: |
8473 | return -ENOTSUPP; | |
8474 | } | |
15d83c4d | 8475 | break; |
e9ddbb77 JS |
8476 | case BPF_PROG_TYPE_SK_LOOKUP: |
8477 | range = tnum_range(SK_DROP, SK_PASS); | |
8478 | break; | |
e92888c7 YS |
8479 | case BPF_PROG_TYPE_EXT: |
8480 | /* freplace program can return anything as its return value | |
8481 | * depends on the to-be-replaced kernel func or bpf program. | |
8482 | */ | |
390ee7e2 AS |
8483 | default: |
8484 | return 0; | |
8485 | } | |
8486 | ||
390ee7e2 | 8487 | if (reg->type != SCALAR_VALUE) { |
61bd5218 | 8488 | verbose(env, "At program exit the register R0 is not a known value (%s)\n", |
390ee7e2 AS |
8489 | reg_type_str[reg->type]); |
8490 | return -EINVAL; | |
8491 | } | |
8492 | ||
8493 | if (!tnum_in(range, reg->var_off)) { | |
5cf1e914 | 8494 | char tn_buf[48]; |
8495 | ||
61bd5218 | 8496 | verbose(env, "At program exit the register R0 "); |
390ee7e2 | 8497 | if (!tnum_is_unknown(reg->var_off)) { |
390ee7e2 | 8498 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); |
61bd5218 | 8499 | verbose(env, "has value %s", tn_buf); |
390ee7e2 | 8500 | } else { |
61bd5218 | 8501 | verbose(env, "has unknown scalar value"); |
390ee7e2 | 8502 | } |
5cf1e914 | 8503 | tnum_strn(tn_buf, sizeof(tn_buf), range); |
983695fa | 8504 | verbose(env, " should have been in %s\n", tn_buf); |
390ee7e2 AS |
8505 | return -EINVAL; |
8506 | } | |
5cf1e914 | 8507 | |
8508 | if (!tnum_is_unknown(enforce_attach_type_range) && | |
8509 | tnum_in(enforce_attach_type_range, reg->var_off)) | |
8510 | env->prog->enforce_expected_attach_type = 1; | |
390ee7e2 AS |
8511 | return 0; |
8512 | } | |
8513 | ||
475fb78f AS |
8514 | /* non-recursive DFS pseudo code |
8515 | * 1 procedure DFS-iterative(G,v): | |
8516 | * 2 label v as discovered | |
8517 | * 3 let S be a stack | |
8518 | * 4 S.push(v) | |
8519 | * 5 while S is not empty | |
8520 | * 6 t <- S.pop() | |
8521 | * 7 if t is what we're looking for: | |
8522 | * 8 return t | |
8523 | * 9 for all edges e in G.adjacentEdges(t) do | |
8524 | * 10 if edge e is already labelled | |
8525 | * 11 continue with the next edge | |
8526 | * 12 w <- G.adjacentVertex(t,e) | |
8527 | * 13 if vertex w is not discovered and not explored | |
8528 | * 14 label e as tree-edge | |
8529 | * 15 label w as discovered | |
8530 | * 16 S.push(w) | |
8531 | * 17 continue at 5 | |
8532 | * 18 else if vertex w is discovered | |
8533 | * 19 label e as back-edge | |
8534 | * 20 else | |
8535 | * 21 // vertex w is explored | |
8536 | * 22 label e as forward- or cross-edge | |
8537 | * 23 label t as explored | |
8538 | * 24 S.pop() | |
8539 | * | |
8540 | * convention: | |
8541 | * 0x10 - discovered | |
8542 | * 0x11 - discovered and fall-through edge labelled | |
8543 | * 0x12 - discovered and fall-through and branch edges labelled | |
8544 | * 0x20 - explored | |
8545 | */ | |
8546 | ||
8547 | enum { | |
8548 | DISCOVERED = 0x10, | |
8549 | EXPLORED = 0x20, | |
8550 | FALLTHROUGH = 1, | |
8551 | BRANCH = 2, | |
8552 | }; | |
8553 | ||
dc2a4ebc AS |
8554 | static u32 state_htab_size(struct bpf_verifier_env *env) |
8555 | { | |
8556 | return env->prog->len; | |
8557 | } | |
8558 | ||
5d839021 AS |
8559 | static struct bpf_verifier_state_list **explored_state( |
8560 | struct bpf_verifier_env *env, | |
8561 | int idx) | |
8562 | { | |
dc2a4ebc AS |
8563 | struct bpf_verifier_state *cur = env->cur_state; |
8564 | struct bpf_func_state *state = cur->frame[cur->curframe]; | |
8565 | ||
8566 | return &env->explored_states[(idx ^ state->callsite) % state_htab_size(env)]; | |
5d839021 AS |
8567 | } |
8568 | ||
8569 | static void init_explored_state(struct bpf_verifier_env *env, int idx) | |
8570 | { | |
a8f500af | 8571 | env->insn_aux_data[idx].prune_point = true; |
5d839021 | 8572 | } |
f1bca824 | 8573 | |
59e2e27d WAF |
8574 | enum { |
8575 | DONE_EXPLORING = 0, | |
8576 | KEEP_EXPLORING = 1, | |
8577 | }; | |
8578 | ||
475fb78f AS |
8579 | /* t, w, e - match pseudo-code above: |
8580 | * t - index of current instruction | |
8581 | * w - next instruction | |
8582 | * e - edge | |
8583 | */ | |
2589726d AS |
8584 | static int push_insn(int t, int w, int e, struct bpf_verifier_env *env, |
8585 | bool loop_ok) | |
475fb78f | 8586 | { |
7df737e9 AS |
8587 | int *insn_stack = env->cfg.insn_stack; |
8588 | int *insn_state = env->cfg.insn_state; | |
8589 | ||
475fb78f | 8590 | if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH)) |
59e2e27d | 8591 | return DONE_EXPLORING; |
475fb78f AS |
8592 | |
8593 | if (e == BRANCH && insn_state[t] >= (DISCOVERED | BRANCH)) | |
59e2e27d | 8594 | return DONE_EXPLORING; |
475fb78f AS |
8595 | |
8596 | if (w < 0 || w >= env->prog->len) { | |
d9762e84 | 8597 | verbose_linfo(env, t, "%d: ", t); |
61bd5218 | 8598 | verbose(env, "jump out of range from insn %d to %d\n", t, w); |
475fb78f AS |
8599 | return -EINVAL; |
8600 | } | |
8601 | ||
f1bca824 AS |
8602 | if (e == BRANCH) |
8603 | /* mark branch target for state pruning */ | |
5d839021 | 8604 | init_explored_state(env, w); |
f1bca824 | 8605 | |
475fb78f AS |
8606 | if (insn_state[w] == 0) { |
8607 | /* tree-edge */ | |
8608 | insn_state[t] = DISCOVERED | e; | |
8609 | insn_state[w] = DISCOVERED; | |
7df737e9 | 8610 | if (env->cfg.cur_stack >= env->prog->len) |
475fb78f | 8611 | return -E2BIG; |
7df737e9 | 8612 | insn_stack[env->cfg.cur_stack++] = w; |
59e2e27d | 8613 | return KEEP_EXPLORING; |
475fb78f | 8614 | } else if ((insn_state[w] & 0xF0) == DISCOVERED) { |
2c78ee89 | 8615 | if (loop_ok && env->bpf_capable) |
59e2e27d | 8616 | return DONE_EXPLORING; |
d9762e84 MKL |
8617 | verbose_linfo(env, t, "%d: ", t); |
8618 | verbose_linfo(env, w, "%d: ", w); | |
61bd5218 | 8619 | verbose(env, "back-edge from insn %d to %d\n", t, w); |
475fb78f AS |
8620 | return -EINVAL; |
8621 | } else if (insn_state[w] == EXPLORED) { | |
8622 | /* forward- or cross-edge */ | |
8623 | insn_state[t] = DISCOVERED | e; | |
8624 | } else { | |
61bd5218 | 8625 | verbose(env, "insn state internal bug\n"); |
475fb78f AS |
8626 | return -EFAULT; |
8627 | } | |
59e2e27d WAF |
8628 | return DONE_EXPLORING; |
8629 | } | |
8630 | ||
8631 | /* Visits the instruction at index t and returns one of the following: | |
8632 | * < 0 - an error occurred | |
8633 | * DONE_EXPLORING - the instruction was fully explored | |
8634 | * KEEP_EXPLORING - there is still work to be done before it is fully explored | |
8635 | */ | |
8636 | static int visit_insn(int t, int insn_cnt, struct bpf_verifier_env *env) | |
8637 | { | |
8638 | struct bpf_insn *insns = env->prog->insnsi; | |
8639 | int ret; | |
8640 | ||
8641 | /* All non-branch instructions have a single fall-through edge. */ | |
8642 | if (BPF_CLASS(insns[t].code) != BPF_JMP && | |
8643 | BPF_CLASS(insns[t].code) != BPF_JMP32) | |
8644 | return push_insn(t, t + 1, FALLTHROUGH, env, false); | |
8645 | ||
8646 | switch (BPF_OP(insns[t].code)) { | |
8647 | case BPF_EXIT: | |
8648 | return DONE_EXPLORING; | |
8649 | ||
8650 | case BPF_CALL: | |
8651 | ret = push_insn(t, t + 1, FALLTHROUGH, env, false); | |
8652 | if (ret) | |
8653 | return ret; | |
8654 | ||
8655 | if (t + 1 < insn_cnt) | |
8656 | init_explored_state(env, t + 1); | |
8657 | if (insns[t].src_reg == BPF_PSEUDO_CALL) { | |
8658 | init_explored_state(env, t); | |
8659 | ret = push_insn(t, t + insns[t].imm + 1, BRANCH, | |
8660 | env, false); | |
8661 | } | |
8662 | return ret; | |
8663 | ||
8664 | case BPF_JA: | |
8665 | if (BPF_SRC(insns[t].code) != BPF_K) | |
8666 | return -EINVAL; | |
8667 | ||
8668 | /* unconditional jump with single edge */ | |
8669 | ret = push_insn(t, t + insns[t].off + 1, FALLTHROUGH, env, | |
8670 | true); | |
8671 | if (ret) | |
8672 | return ret; | |
8673 | ||
8674 | /* unconditional jmp is not a good pruning point, | |
8675 | * but it's marked, since backtracking needs | |
8676 | * to record jmp history in is_state_visited(). | |
8677 | */ | |
8678 | init_explored_state(env, t + insns[t].off + 1); | |
8679 | /* tell verifier to check for equivalent states | |
8680 | * after every call and jump | |
8681 | */ | |
8682 | if (t + 1 < insn_cnt) | |
8683 | init_explored_state(env, t + 1); | |
8684 | ||
8685 | return ret; | |
8686 | ||
8687 | default: | |
8688 | /* conditional jump with two edges */ | |
8689 | init_explored_state(env, t); | |
8690 | ret = push_insn(t, t + 1, FALLTHROUGH, env, true); | |
8691 | if (ret) | |
8692 | return ret; | |
8693 | ||
8694 | return push_insn(t, t + insns[t].off + 1, BRANCH, env, true); | |
8695 | } | |
475fb78f AS |
8696 | } |
8697 | ||
8698 | /* non-recursive depth-first-search to detect loops in BPF program | |
8699 | * loop == back-edge in directed graph | |
8700 | */ | |
58e2af8b | 8701 | static int check_cfg(struct bpf_verifier_env *env) |
475fb78f | 8702 | { |
475fb78f | 8703 | int insn_cnt = env->prog->len; |
7df737e9 | 8704 | int *insn_stack, *insn_state; |
475fb78f | 8705 | int ret = 0; |
59e2e27d | 8706 | int i; |
475fb78f | 8707 | |
7df737e9 | 8708 | insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL); |
475fb78f AS |
8709 | if (!insn_state) |
8710 | return -ENOMEM; | |
8711 | ||
7df737e9 | 8712 | insn_stack = env->cfg.insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL); |
475fb78f | 8713 | if (!insn_stack) { |
71dde681 | 8714 | kvfree(insn_state); |
475fb78f AS |
8715 | return -ENOMEM; |
8716 | } | |
8717 | ||
8718 | insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */ | |
8719 | insn_stack[0] = 0; /* 0 is the first instruction */ | |
7df737e9 | 8720 | env->cfg.cur_stack = 1; |
475fb78f | 8721 | |
59e2e27d WAF |
8722 | while (env->cfg.cur_stack > 0) { |
8723 | int t = insn_stack[env->cfg.cur_stack - 1]; | |
475fb78f | 8724 | |
59e2e27d WAF |
8725 | ret = visit_insn(t, insn_cnt, env); |
8726 | switch (ret) { | |
8727 | case DONE_EXPLORING: | |
8728 | insn_state[t] = EXPLORED; | |
8729 | env->cfg.cur_stack--; | |
8730 | break; | |
8731 | case KEEP_EXPLORING: | |
8732 | break; | |
8733 | default: | |
8734 | if (ret > 0) { | |
8735 | verbose(env, "visit_insn internal bug\n"); | |
8736 | ret = -EFAULT; | |
475fb78f | 8737 | } |
475fb78f | 8738 | goto err_free; |
59e2e27d | 8739 | } |
475fb78f AS |
8740 | } |
8741 | ||
59e2e27d | 8742 | if (env->cfg.cur_stack < 0) { |
61bd5218 | 8743 | verbose(env, "pop stack internal bug\n"); |
475fb78f AS |
8744 | ret = -EFAULT; |
8745 | goto err_free; | |
8746 | } | |
475fb78f | 8747 | |
475fb78f AS |
8748 | for (i = 0; i < insn_cnt; i++) { |
8749 | if (insn_state[i] != EXPLORED) { | |
61bd5218 | 8750 | verbose(env, "unreachable insn %d\n", i); |
475fb78f AS |
8751 | ret = -EINVAL; |
8752 | goto err_free; | |
8753 | } | |
8754 | } | |
8755 | ret = 0; /* cfg looks good */ | |
8756 | ||
8757 | err_free: | |
71dde681 AS |
8758 | kvfree(insn_state); |
8759 | kvfree(insn_stack); | |
7df737e9 | 8760 | env->cfg.insn_state = env->cfg.insn_stack = NULL; |
475fb78f AS |
8761 | return ret; |
8762 | } | |
8763 | ||
09b28d76 AS |
8764 | static int check_abnormal_return(struct bpf_verifier_env *env) |
8765 | { | |
8766 | int i; | |
8767 | ||
8768 | for (i = 1; i < env->subprog_cnt; i++) { | |
8769 | if (env->subprog_info[i].has_ld_abs) { | |
8770 | verbose(env, "LD_ABS is not allowed in subprogs without BTF\n"); | |
8771 | return -EINVAL; | |
8772 | } | |
8773 | if (env->subprog_info[i].has_tail_call) { | |
8774 | verbose(env, "tail_call is not allowed in subprogs without BTF\n"); | |
8775 | return -EINVAL; | |
8776 | } | |
8777 | } | |
8778 | return 0; | |
8779 | } | |
8780 | ||
838e9690 YS |
8781 | /* The minimum supported BTF func info size */ |
8782 | #define MIN_BPF_FUNCINFO_SIZE 8 | |
8783 | #define MAX_FUNCINFO_REC_SIZE 252 | |
8784 | ||
c454a46b MKL |
8785 | static int check_btf_func(struct bpf_verifier_env *env, |
8786 | const union bpf_attr *attr, | |
8787 | union bpf_attr __user *uattr) | |
838e9690 | 8788 | { |
09b28d76 | 8789 | const struct btf_type *type, *func_proto, *ret_type; |
d0b2818e | 8790 | u32 i, nfuncs, urec_size, min_size; |
838e9690 | 8791 | u32 krec_size = sizeof(struct bpf_func_info); |
c454a46b | 8792 | struct bpf_func_info *krecord; |
8c1b6e69 | 8793 | struct bpf_func_info_aux *info_aux = NULL; |
c454a46b MKL |
8794 | struct bpf_prog *prog; |
8795 | const struct btf *btf; | |
838e9690 | 8796 | void __user *urecord; |
d0b2818e | 8797 | u32 prev_offset = 0; |
09b28d76 | 8798 | bool scalar_return; |
e7ed83d6 | 8799 | int ret = -ENOMEM; |
838e9690 YS |
8800 | |
8801 | nfuncs = attr->func_info_cnt; | |
09b28d76 AS |
8802 | if (!nfuncs) { |
8803 | if (check_abnormal_return(env)) | |
8804 | return -EINVAL; | |
838e9690 | 8805 | return 0; |
09b28d76 | 8806 | } |
838e9690 YS |
8807 | |
8808 | if (nfuncs != env->subprog_cnt) { | |
8809 | verbose(env, "number of funcs in func_info doesn't match number of subprogs\n"); | |
8810 | return -EINVAL; | |
8811 | } | |
8812 | ||
8813 | urec_size = attr->func_info_rec_size; | |
8814 | if (urec_size < MIN_BPF_FUNCINFO_SIZE || | |
8815 | urec_size > MAX_FUNCINFO_REC_SIZE || | |
8816 | urec_size % sizeof(u32)) { | |
8817 | verbose(env, "invalid func info rec size %u\n", urec_size); | |
8818 | return -EINVAL; | |
8819 | } | |
8820 | ||
c454a46b MKL |
8821 | prog = env->prog; |
8822 | btf = prog->aux->btf; | |
838e9690 YS |
8823 | |
8824 | urecord = u64_to_user_ptr(attr->func_info); | |
8825 | min_size = min_t(u32, krec_size, urec_size); | |
8826 | ||
ba64e7d8 | 8827 | krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN); |
c454a46b MKL |
8828 | if (!krecord) |
8829 | return -ENOMEM; | |
8c1b6e69 AS |
8830 | info_aux = kcalloc(nfuncs, sizeof(*info_aux), GFP_KERNEL | __GFP_NOWARN); |
8831 | if (!info_aux) | |
8832 | goto err_free; | |
ba64e7d8 | 8833 | |
838e9690 YS |
8834 | for (i = 0; i < nfuncs; i++) { |
8835 | ret = bpf_check_uarg_tail_zero(urecord, krec_size, urec_size); | |
8836 | if (ret) { | |
8837 | if (ret == -E2BIG) { | |
8838 | verbose(env, "nonzero tailing record in func info"); | |
8839 | /* set the size kernel expects so loader can zero | |
8840 | * out the rest of the record. | |
8841 | */ | |
8842 | if (put_user(min_size, &uattr->func_info_rec_size)) | |
8843 | ret = -EFAULT; | |
8844 | } | |
c454a46b | 8845 | goto err_free; |
838e9690 YS |
8846 | } |
8847 | ||
ba64e7d8 | 8848 | if (copy_from_user(&krecord[i], urecord, min_size)) { |
838e9690 | 8849 | ret = -EFAULT; |
c454a46b | 8850 | goto err_free; |
838e9690 YS |
8851 | } |
8852 | ||
d30d42e0 | 8853 | /* check insn_off */ |
09b28d76 | 8854 | ret = -EINVAL; |
838e9690 | 8855 | if (i == 0) { |
d30d42e0 | 8856 | if (krecord[i].insn_off) { |
838e9690 | 8857 | verbose(env, |
d30d42e0 MKL |
8858 | "nonzero insn_off %u for the first func info record", |
8859 | krecord[i].insn_off); | |
c454a46b | 8860 | goto err_free; |
838e9690 | 8861 | } |
d30d42e0 | 8862 | } else if (krecord[i].insn_off <= prev_offset) { |
838e9690 YS |
8863 | verbose(env, |
8864 | "same or smaller insn offset (%u) than previous func info record (%u)", | |
d30d42e0 | 8865 | krecord[i].insn_off, prev_offset); |
c454a46b | 8866 | goto err_free; |
838e9690 YS |
8867 | } |
8868 | ||
d30d42e0 | 8869 | if (env->subprog_info[i].start != krecord[i].insn_off) { |
838e9690 | 8870 | verbose(env, "func_info BTF section doesn't match subprog layout in BPF program\n"); |
c454a46b | 8871 | goto err_free; |
838e9690 YS |
8872 | } |
8873 | ||
8874 | /* check type_id */ | |
ba64e7d8 | 8875 | type = btf_type_by_id(btf, krecord[i].type_id); |
51c39bb1 | 8876 | if (!type || !btf_type_is_func(type)) { |
838e9690 | 8877 | verbose(env, "invalid type id %d in func info", |
ba64e7d8 | 8878 | krecord[i].type_id); |
c454a46b | 8879 | goto err_free; |
838e9690 | 8880 | } |
51c39bb1 | 8881 | info_aux[i].linkage = BTF_INFO_VLEN(type->info); |
09b28d76 AS |
8882 | |
8883 | func_proto = btf_type_by_id(btf, type->type); | |
8884 | if (unlikely(!func_proto || !btf_type_is_func_proto(func_proto))) | |
8885 | /* btf_func_check() already verified it during BTF load */ | |
8886 | goto err_free; | |
8887 | ret_type = btf_type_skip_modifiers(btf, func_proto->type, NULL); | |
8888 | scalar_return = | |
8889 | btf_type_is_small_int(ret_type) || btf_type_is_enum(ret_type); | |
8890 | if (i && !scalar_return && env->subprog_info[i].has_ld_abs) { | |
8891 | verbose(env, "LD_ABS is only allowed in functions that return 'int'.\n"); | |
8892 | goto err_free; | |
8893 | } | |
8894 | if (i && !scalar_return && env->subprog_info[i].has_tail_call) { | |
8895 | verbose(env, "tail_call is only allowed in functions that return 'int'.\n"); | |
8896 | goto err_free; | |
8897 | } | |
8898 | ||
d30d42e0 | 8899 | prev_offset = krecord[i].insn_off; |
838e9690 YS |
8900 | urecord += urec_size; |
8901 | } | |
8902 | ||
ba64e7d8 YS |
8903 | prog->aux->func_info = krecord; |
8904 | prog->aux->func_info_cnt = nfuncs; | |
8c1b6e69 | 8905 | prog->aux->func_info_aux = info_aux; |
838e9690 YS |
8906 | return 0; |
8907 | ||
c454a46b | 8908 | err_free: |
ba64e7d8 | 8909 | kvfree(krecord); |
8c1b6e69 | 8910 | kfree(info_aux); |
838e9690 YS |
8911 | return ret; |
8912 | } | |
8913 | ||
ba64e7d8 YS |
8914 | static void adjust_btf_func(struct bpf_verifier_env *env) |
8915 | { | |
8c1b6e69 | 8916 | struct bpf_prog_aux *aux = env->prog->aux; |
ba64e7d8 YS |
8917 | int i; |
8918 | ||
8c1b6e69 | 8919 | if (!aux->func_info) |
ba64e7d8 YS |
8920 | return; |
8921 | ||
8922 | for (i = 0; i < env->subprog_cnt; i++) | |
8c1b6e69 | 8923 | aux->func_info[i].insn_off = env->subprog_info[i].start; |
ba64e7d8 YS |
8924 | } |
8925 | ||
c454a46b MKL |
8926 | #define MIN_BPF_LINEINFO_SIZE (offsetof(struct bpf_line_info, line_col) + \ |
8927 | sizeof(((struct bpf_line_info *)(0))->line_col)) | |
8928 | #define MAX_LINEINFO_REC_SIZE MAX_FUNCINFO_REC_SIZE | |
8929 | ||
8930 | static int check_btf_line(struct bpf_verifier_env *env, | |
8931 | const union bpf_attr *attr, | |
8932 | union bpf_attr __user *uattr) | |
8933 | { | |
8934 | u32 i, s, nr_linfo, ncopy, expected_size, rec_size, prev_offset = 0; | |
8935 | struct bpf_subprog_info *sub; | |
8936 | struct bpf_line_info *linfo; | |
8937 | struct bpf_prog *prog; | |
8938 | const struct btf *btf; | |
8939 | void __user *ulinfo; | |
8940 | int err; | |
8941 | ||
8942 | nr_linfo = attr->line_info_cnt; | |
8943 | if (!nr_linfo) | |
8944 | return 0; | |
8945 | ||
8946 | rec_size = attr->line_info_rec_size; | |
8947 | if (rec_size < MIN_BPF_LINEINFO_SIZE || | |
8948 | rec_size > MAX_LINEINFO_REC_SIZE || | |
8949 | rec_size & (sizeof(u32) - 1)) | |
8950 | return -EINVAL; | |
8951 | ||
8952 | /* Need to zero it in case the userspace may | |
8953 | * pass in a smaller bpf_line_info object. | |
8954 | */ | |
8955 | linfo = kvcalloc(nr_linfo, sizeof(struct bpf_line_info), | |
8956 | GFP_KERNEL | __GFP_NOWARN); | |
8957 | if (!linfo) | |
8958 | return -ENOMEM; | |
8959 | ||
8960 | prog = env->prog; | |
8961 | btf = prog->aux->btf; | |
8962 | ||
8963 | s = 0; | |
8964 | sub = env->subprog_info; | |
8965 | ulinfo = u64_to_user_ptr(attr->line_info); | |
8966 | expected_size = sizeof(struct bpf_line_info); | |
8967 | ncopy = min_t(u32, expected_size, rec_size); | |
8968 | for (i = 0; i < nr_linfo; i++) { | |
8969 | err = bpf_check_uarg_tail_zero(ulinfo, expected_size, rec_size); | |
8970 | if (err) { | |
8971 | if (err == -E2BIG) { | |
8972 | verbose(env, "nonzero tailing record in line_info"); | |
8973 | if (put_user(expected_size, | |
8974 | &uattr->line_info_rec_size)) | |
8975 | err = -EFAULT; | |
8976 | } | |
8977 | goto err_free; | |
8978 | } | |
8979 | ||
8980 | if (copy_from_user(&linfo[i], ulinfo, ncopy)) { | |
8981 | err = -EFAULT; | |
8982 | goto err_free; | |
8983 | } | |
8984 | ||
8985 | /* | |
8986 | * Check insn_off to ensure | |
8987 | * 1) strictly increasing AND | |
8988 | * 2) bounded by prog->len | |
8989 | * | |
8990 | * The linfo[0].insn_off == 0 check logically falls into | |
8991 | * the later "missing bpf_line_info for func..." case | |
8992 | * because the first linfo[0].insn_off must be the | |
8993 | * first sub also and the first sub must have | |
8994 | * subprog_info[0].start == 0. | |
8995 | */ | |
8996 | if ((i && linfo[i].insn_off <= prev_offset) || | |
8997 | linfo[i].insn_off >= prog->len) { | |
8998 | verbose(env, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n", | |
8999 | i, linfo[i].insn_off, prev_offset, | |
9000 | prog->len); | |
9001 | err = -EINVAL; | |
9002 | goto err_free; | |
9003 | } | |
9004 | ||
fdbaa0be MKL |
9005 | if (!prog->insnsi[linfo[i].insn_off].code) { |
9006 | verbose(env, | |
9007 | "Invalid insn code at line_info[%u].insn_off\n", | |
9008 | i); | |
9009 | err = -EINVAL; | |
9010 | goto err_free; | |
9011 | } | |
9012 | ||
23127b33 MKL |
9013 | if (!btf_name_by_offset(btf, linfo[i].line_off) || |
9014 | !btf_name_by_offset(btf, linfo[i].file_name_off)) { | |
c454a46b MKL |
9015 | verbose(env, "Invalid line_info[%u].line_off or .file_name_off\n", i); |
9016 | err = -EINVAL; | |
9017 | goto err_free; | |
9018 | } | |
9019 | ||
9020 | if (s != env->subprog_cnt) { | |
9021 | if (linfo[i].insn_off == sub[s].start) { | |
9022 | sub[s].linfo_idx = i; | |
9023 | s++; | |
9024 | } else if (sub[s].start < linfo[i].insn_off) { | |
9025 | verbose(env, "missing bpf_line_info for func#%u\n", s); | |
9026 | err = -EINVAL; | |
9027 | goto err_free; | |
9028 | } | |
9029 | } | |
9030 | ||
9031 | prev_offset = linfo[i].insn_off; | |
9032 | ulinfo += rec_size; | |
9033 | } | |
9034 | ||
9035 | if (s != env->subprog_cnt) { | |
9036 | verbose(env, "missing bpf_line_info for %u funcs starting from func#%u\n", | |
9037 | env->subprog_cnt - s, s); | |
9038 | err = -EINVAL; | |
9039 | goto err_free; | |
9040 | } | |
9041 | ||
9042 | prog->aux->linfo = linfo; | |
9043 | prog->aux->nr_linfo = nr_linfo; | |
9044 | ||
9045 | return 0; | |
9046 | ||
9047 | err_free: | |
9048 | kvfree(linfo); | |
9049 | return err; | |
9050 | } | |
9051 | ||
9052 | static int check_btf_info(struct bpf_verifier_env *env, | |
9053 | const union bpf_attr *attr, | |
9054 | union bpf_attr __user *uattr) | |
9055 | { | |
9056 | struct btf *btf; | |
9057 | int err; | |
9058 | ||
09b28d76 AS |
9059 | if (!attr->func_info_cnt && !attr->line_info_cnt) { |
9060 | if (check_abnormal_return(env)) | |
9061 | return -EINVAL; | |
c454a46b | 9062 | return 0; |
09b28d76 | 9063 | } |
c454a46b MKL |
9064 | |
9065 | btf = btf_get_by_fd(attr->prog_btf_fd); | |
9066 | if (IS_ERR(btf)) | |
9067 | return PTR_ERR(btf); | |
350a5c4d AS |
9068 | if (btf_is_kernel(btf)) { |
9069 | btf_put(btf); | |
9070 | return -EACCES; | |
9071 | } | |
c454a46b MKL |
9072 | env->prog->aux->btf = btf; |
9073 | ||
9074 | err = check_btf_func(env, attr, uattr); | |
9075 | if (err) | |
9076 | return err; | |
9077 | ||
9078 | err = check_btf_line(env, attr, uattr); | |
9079 | if (err) | |
9080 | return err; | |
9081 | ||
9082 | return 0; | |
ba64e7d8 YS |
9083 | } |
9084 | ||
f1174f77 EC |
9085 | /* check %cur's range satisfies %old's */ |
9086 | static bool range_within(struct bpf_reg_state *old, | |
9087 | struct bpf_reg_state *cur) | |
9088 | { | |
b03c9f9f EC |
9089 | return old->umin_value <= cur->umin_value && |
9090 | old->umax_value >= cur->umax_value && | |
9091 | old->smin_value <= cur->smin_value && | |
fd675184 DB |
9092 | old->smax_value >= cur->smax_value && |
9093 | old->u32_min_value <= cur->u32_min_value && | |
9094 | old->u32_max_value >= cur->u32_max_value && | |
9095 | old->s32_min_value <= cur->s32_min_value && | |
9096 | old->s32_max_value >= cur->s32_max_value; | |
f1174f77 EC |
9097 | } |
9098 | ||
9099 | /* Maximum number of register states that can exist at once */ | |
9100 | #define ID_MAP_SIZE (MAX_BPF_REG + MAX_BPF_STACK / BPF_REG_SIZE) | |
9101 | struct idpair { | |
9102 | u32 old; | |
9103 | u32 cur; | |
9104 | }; | |
9105 | ||
9106 | /* If in the old state two registers had the same id, then they need to have | |
9107 | * the same id in the new state as well. But that id could be different from | |
9108 | * the old state, so we need to track the mapping from old to new ids. | |
9109 | * Once we have seen that, say, a reg with old id 5 had new id 9, any subsequent | |
9110 | * regs with old id 5 must also have new id 9 for the new state to be safe. But | |
9111 | * regs with a different old id could still have new id 9, we don't care about | |
9112 | * that. | |
9113 | * So we look through our idmap to see if this old id has been seen before. If | |
9114 | * so, we require the new id to match; otherwise, we add the id pair to the map. | |
969bf05e | 9115 | */ |
f1174f77 | 9116 | static bool check_ids(u32 old_id, u32 cur_id, struct idpair *idmap) |
969bf05e | 9117 | { |
f1174f77 | 9118 | unsigned int i; |
969bf05e | 9119 | |
f1174f77 EC |
9120 | for (i = 0; i < ID_MAP_SIZE; i++) { |
9121 | if (!idmap[i].old) { | |
9122 | /* Reached an empty slot; haven't seen this id before */ | |
9123 | idmap[i].old = old_id; | |
9124 | idmap[i].cur = cur_id; | |
9125 | return true; | |
9126 | } | |
9127 | if (idmap[i].old == old_id) | |
9128 | return idmap[i].cur == cur_id; | |
9129 | } | |
9130 | /* We ran out of idmap slots, which should be impossible */ | |
9131 | WARN_ON_ONCE(1); | |
9132 | return false; | |
9133 | } | |
9134 | ||
9242b5f5 AS |
9135 | static void clean_func_state(struct bpf_verifier_env *env, |
9136 | struct bpf_func_state *st) | |
9137 | { | |
9138 | enum bpf_reg_liveness live; | |
9139 | int i, j; | |
9140 | ||
9141 | for (i = 0; i < BPF_REG_FP; i++) { | |
9142 | live = st->regs[i].live; | |
9143 | /* liveness must not touch this register anymore */ | |
9144 | st->regs[i].live |= REG_LIVE_DONE; | |
9145 | if (!(live & REG_LIVE_READ)) | |
9146 | /* since the register is unused, clear its state | |
9147 | * to make further comparison simpler | |
9148 | */ | |
f54c7898 | 9149 | __mark_reg_not_init(env, &st->regs[i]); |
9242b5f5 AS |
9150 | } |
9151 | ||
9152 | for (i = 0; i < st->allocated_stack / BPF_REG_SIZE; i++) { | |
9153 | live = st->stack[i].spilled_ptr.live; | |
9154 | /* liveness must not touch this stack slot anymore */ | |
9155 | st->stack[i].spilled_ptr.live |= REG_LIVE_DONE; | |
9156 | if (!(live & REG_LIVE_READ)) { | |
f54c7898 | 9157 | __mark_reg_not_init(env, &st->stack[i].spilled_ptr); |
9242b5f5 AS |
9158 | for (j = 0; j < BPF_REG_SIZE; j++) |
9159 | st->stack[i].slot_type[j] = STACK_INVALID; | |
9160 | } | |
9161 | } | |
9162 | } | |
9163 | ||
9164 | static void clean_verifier_state(struct bpf_verifier_env *env, | |
9165 | struct bpf_verifier_state *st) | |
9166 | { | |
9167 | int i; | |
9168 | ||
9169 | if (st->frame[0]->regs[0].live & REG_LIVE_DONE) | |
9170 | /* all regs in this state in all frames were already marked */ | |
9171 | return; | |
9172 | ||
9173 | for (i = 0; i <= st->curframe; i++) | |
9174 | clean_func_state(env, st->frame[i]); | |
9175 | } | |
9176 | ||
9177 | /* the parentage chains form a tree. | |
9178 | * the verifier states are added to state lists at given insn and | |
9179 | * pushed into state stack for future exploration. | |
9180 | * when the verifier reaches bpf_exit insn some of the verifer states | |
9181 | * stored in the state lists have their final liveness state already, | |
9182 | * but a lot of states will get revised from liveness point of view when | |
9183 | * the verifier explores other branches. | |
9184 | * Example: | |
9185 | * 1: r0 = 1 | |
9186 | * 2: if r1 == 100 goto pc+1 | |
9187 | * 3: r0 = 2 | |
9188 | * 4: exit | |
9189 | * when the verifier reaches exit insn the register r0 in the state list of | |
9190 | * insn 2 will be seen as !REG_LIVE_READ. Then the verifier pops the other_branch | |
9191 | * of insn 2 and goes exploring further. At the insn 4 it will walk the | |
9192 | * parentage chain from insn 4 into insn 2 and will mark r0 as REG_LIVE_READ. | |
9193 | * | |
9194 | * Since the verifier pushes the branch states as it sees them while exploring | |
9195 | * the program the condition of walking the branch instruction for the second | |
9196 | * time means that all states below this branch were already explored and | |
9197 | * their final liveness markes are already propagated. | |
9198 | * Hence when the verifier completes the search of state list in is_state_visited() | |
9199 | * we can call this clean_live_states() function to mark all liveness states | |
9200 | * as REG_LIVE_DONE to indicate that 'parent' pointers of 'struct bpf_reg_state' | |
9201 | * will not be used. | |
9202 | * This function also clears the registers and stack for states that !READ | |
9203 | * to simplify state merging. | |
9204 | * | |
9205 | * Important note here that walking the same branch instruction in the callee | |
9206 | * doesn't meant that the states are DONE. The verifier has to compare | |
9207 | * the callsites | |
9208 | */ | |
9209 | static void clean_live_states(struct bpf_verifier_env *env, int insn, | |
9210 | struct bpf_verifier_state *cur) | |
9211 | { | |
9212 | struct bpf_verifier_state_list *sl; | |
9213 | int i; | |
9214 | ||
5d839021 | 9215 | sl = *explored_state(env, insn); |
a8f500af | 9216 | while (sl) { |
2589726d AS |
9217 | if (sl->state.branches) |
9218 | goto next; | |
dc2a4ebc AS |
9219 | if (sl->state.insn_idx != insn || |
9220 | sl->state.curframe != cur->curframe) | |
9242b5f5 AS |
9221 | goto next; |
9222 | for (i = 0; i <= cur->curframe; i++) | |
9223 | if (sl->state.frame[i]->callsite != cur->frame[i]->callsite) | |
9224 | goto next; | |
9225 | clean_verifier_state(env, &sl->state); | |
9226 | next: | |
9227 | sl = sl->next; | |
9228 | } | |
9229 | } | |
9230 | ||
f1174f77 | 9231 | /* Returns true if (rold safe implies rcur safe) */ |
1b688a19 EC |
9232 | static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur, |
9233 | struct idpair *idmap) | |
f1174f77 | 9234 | { |
f4d7e40a AS |
9235 | bool equal; |
9236 | ||
dc503a8a EC |
9237 | if (!(rold->live & REG_LIVE_READ)) |
9238 | /* explored state didn't use this */ | |
9239 | return true; | |
9240 | ||
679c782d | 9241 | equal = memcmp(rold, rcur, offsetof(struct bpf_reg_state, parent)) == 0; |
f4d7e40a AS |
9242 | |
9243 | if (rold->type == PTR_TO_STACK) | |
9244 | /* two stack pointers are equal only if they're pointing to | |
9245 | * the same stack frame, since fp-8 in foo != fp-8 in bar | |
9246 | */ | |
9247 | return equal && rold->frameno == rcur->frameno; | |
9248 | ||
9249 | if (equal) | |
969bf05e AS |
9250 | return true; |
9251 | ||
f1174f77 EC |
9252 | if (rold->type == NOT_INIT) |
9253 | /* explored state can't have used this */ | |
969bf05e | 9254 | return true; |
f1174f77 EC |
9255 | if (rcur->type == NOT_INIT) |
9256 | return false; | |
9257 | switch (rold->type) { | |
9258 | case SCALAR_VALUE: | |
9259 | if (rcur->type == SCALAR_VALUE) { | |
b5dc0163 AS |
9260 | if (!rold->precise && !rcur->precise) |
9261 | return true; | |
f1174f77 EC |
9262 | /* new val must satisfy old val knowledge */ |
9263 | return range_within(rold, rcur) && | |
9264 | tnum_in(rold->var_off, rcur->var_off); | |
9265 | } else { | |
179d1c56 JH |
9266 | /* We're trying to use a pointer in place of a scalar. |
9267 | * Even if the scalar was unbounded, this could lead to | |
9268 | * pointer leaks because scalars are allowed to leak | |
9269 | * while pointers are not. We could make this safe in | |
9270 | * special cases if root is calling us, but it's | |
9271 | * probably not worth the hassle. | |
f1174f77 | 9272 | */ |
179d1c56 | 9273 | return false; |
f1174f77 EC |
9274 | } |
9275 | case PTR_TO_MAP_VALUE: | |
1b688a19 EC |
9276 | /* If the new min/max/var_off satisfy the old ones and |
9277 | * everything else matches, we are OK. | |
d83525ca AS |
9278 | * 'id' is not compared, since it's only used for maps with |
9279 | * bpf_spin_lock inside map element and in such cases if | |
9280 | * the rest of the prog is valid for one map element then | |
9281 | * it's valid for all map elements regardless of the key | |
9282 | * used in bpf_map_lookup() | |
1b688a19 EC |
9283 | */ |
9284 | return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 && | |
9285 | range_within(rold, rcur) && | |
9286 | tnum_in(rold->var_off, rcur->var_off); | |
f1174f77 EC |
9287 | case PTR_TO_MAP_VALUE_OR_NULL: |
9288 | /* a PTR_TO_MAP_VALUE could be safe to use as a | |
9289 | * PTR_TO_MAP_VALUE_OR_NULL into the same map. | |
9290 | * However, if the old PTR_TO_MAP_VALUE_OR_NULL then got NULL- | |
9291 | * checked, doing so could have affected others with the same | |
9292 | * id, and we can't check for that because we lost the id when | |
9293 | * we converted to a PTR_TO_MAP_VALUE. | |
9294 | */ | |
9295 | if (rcur->type != PTR_TO_MAP_VALUE_OR_NULL) | |
9296 | return false; | |
9297 | if (memcmp(rold, rcur, offsetof(struct bpf_reg_state, id))) | |
9298 | return false; | |
9299 | /* Check our ids match any regs they're supposed to */ | |
9300 | return check_ids(rold->id, rcur->id, idmap); | |
de8f3a83 | 9301 | case PTR_TO_PACKET_META: |
f1174f77 | 9302 | case PTR_TO_PACKET: |
de8f3a83 | 9303 | if (rcur->type != rold->type) |
f1174f77 EC |
9304 | return false; |
9305 | /* We must have at least as much range as the old ptr | |
9306 | * did, so that any accesses which were safe before are | |
9307 | * still safe. This is true even if old range < old off, | |
9308 | * since someone could have accessed through (ptr - k), or | |
9309 | * even done ptr -= k in a register, to get a safe access. | |
9310 | */ | |
9311 | if (rold->range > rcur->range) | |
9312 | return false; | |
9313 | /* If the offsets don't match, we can't trust our alignment; | |
9314 | * nor can we be sure that we won't fall out of range. | |
9315 | */ | |
9316 | if (rold->off != rcur->off) | |
9317 | return false; | |
9318 | /* id relations must be preserved */ | |
9319 | if (rold->id && !check_ids(rold->id, rcur->id, idmap)) | |
9320 | return false; | |
9321 | /* new val must satisfy old val knowledge */ | |
9322 | return range_within(rold, rcur) && | |
9323 | tnum_in(rold->var_off, rcur->var_off); | |
9324 | case PTR_TO_CTX: | |
9325 | case CONST_PTR_TO_MAP: | |
f1174f77 | 9326 | case PTR_TO_PACKET_END: |
d58e468b | 9327 | case PTR_TO_FLOW_KEYS: |
c64b7983 JS |
9328 | case PTR_TO_SOCKET: |
9329 | case PTR_TO_SOCKET_OR_NULL: | |
46f8bc92 MKL |
9330 | case PTR_TO_SOCK_COMMON: |
9331 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
655a51e5 MKL |
9332 | case PTR_TO_TCP_SOCK: |
9333 | case PTR_TO_TCP_SOCK_OR_NULL: | |
fada7fdc | 9334 | case PTR_TO_XDP_SOCK: |
f1174f77 EC |
9335 | /* Only valid matches are exact, which memcmp() above |
9336 | * would have accepted | |
9337 | */ | |
9338 | default: | |
9339 | /* Don't know what's going on, just say it's not safe */ | |
9340 | return false; | |
9341 | } | |
969bf05e | 9342 | |
f1174f77 EC |
9343 | /* Shouldn't get here; if we do, say it's not safe */ |
9344 | WARN_ON_ONCE(1); | |
969bf05e AS |
9345 | return false; |
9346 | } | |
9347 | ||
f4d7e40a AS |
9348 | static bool stacksafe(struct bpf_func_state *old, |
9349 | struct bpf_func_state *cur, | |
638f5b90 AS |
9350 | struct idpair *idmap) |
9351 | { | |
9352 | int i, spi; | |
9353 | ||
638f5b90 AS |
9354 | /* walk slots of the explored stack and ignore any additional |
9355 | * slots in the current stack, since explored(safe) state | |
9356 | * didn't use them | |
9357 | */ | |
9358 | for (i = 0; i < old->allocated_stack; i++) { | |
9359 | spi = i / BPF_REG_SIZE; | |
9360 | ||
b233920c AS |
9361 | if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ)) { |
9362 | i += BPF_REG_SIZE - 1; | |
cc2b14d5 | 9363 | /* explored state didn't use this */ |
fd05e57b | 9364 | continue; |
b233920c | 9365 | } |
cc2b14d5 | 9366 | |
638f5b90 AS |
9367 | if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_INVALID) |
9368 | continue; | |
19e2dbb7 AS |
9369 | |
9370 | /* explored stack has more populated slots than current stack | |
9371 | * and these slots were used | |
9372 | */ | |
9373 | if (i >= cur->allocated_stack) | |
9374 | return false; | |
9375 | ||
cc2b14d5 AS |
9376 | /* if old state was safe with misc data in the stack |
9377 | * it will be safe with zero-initialized stack. | |
9378 | * The opposite is not true | |
9379 | */ | |
9380 | if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC && | |
9381 | cur->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_ZERO) | |
9382 | continue; | |
638f5b90 AS |
9383 | if (old->stack[spi].slot_type[i % BPF_REG_SIZE] != |
9384 | cur->stack[spi].slot_type[i % BPF_REG_SIZE]) | |
9385 | /* Ex: old explored (safe) state has STACK_SPILL in | |
b8c1a309 | 9386 | * this stack slot, but current has STACK_MISC -> |
638f5b90 AS |
9387 | * this verifier states are not equivalent, |
9388 | * return false to continue verification of this path | |
9389 | */ | |
9390 | return false; | |
9391 | if (i % BPF_REG_SIZE) | |
9392 | continue; | |
9393 | if (old->stack[spi].slot_type[0] != STACK_SPILL) | |
9394 | continue; | |
9395 | if (!regsafe(&old->stack[spi].spilled_ptr, | |
9396 | &cur->stack[spi].spilled_ptr, | |
9397 | idmap)) | |
9398 | /* when explored and current stack slot are both storing | |
9399 | * spilled registers, check that stored pointers types | |
9400 | * are the same as well. | |
9401 | * Ex: explored safe path could have stored | |
9402 | * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8} | |
9403 | * but current path has stored: | |
9404 | * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16} | |
9405 | * such verifier states are not equivalent. | |
9406 | * return false to continue verification of this path | |
9407 | */ | |
9408 | return false; | |
9409 | } | |
9410 | return true; | |
9411 | } | |
9412 | ||
fd978bf7 JS |
9413 | static bool refsafe(struct bpf_func_state *old, struct bpf_func_state *cur) |
9414 | { | |
9415 | if (old->acquired_refs != cur->acquired_refs) | |
9416 | return false; | |
9417 | return !memcmp(old->refs, cur->refs, | |
9418 | sizeof(*old->refs) * old->acquired_refs); | |
9419 | } | |
9420 | ||
f1bca824 AS |
9421 | /* compare two verifier states |
9422 | * | |
9423 | * all states stored in state_list are known to be valid, since | |
9424 | * verifier reached 'bpf_exit' instruction through them | |
9425 | * | |
9426 | * this function is called when verifier exploring different branches of | |
9427 | * execution popped from the state stack. If it sees an old state that has | |
9428 | * more strict register state and more strict stack state then this execution | |
9429 | * branch doesn't need to be explored further, since verifier already | |
9430 | * concluded that more strict state leads to valid finish. | |
9431 | * | |
9432 | * Therefore two states are equivalent if register state is more conservative | |
9433 | * and explored stack state is more conservative than the current one. | |
9434 | * Example: | |
9435 | * explored current | |
9436 | * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC) | |
9437 | * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC) | |
9438 | * | |
9439 | * In other words if current stack state (one being explored) has more | |
9440 | * valid slots than old one that already passed validation, it means | |
9441 | * the verifier can stop exploring and conclude that current state is valid too | |
9442 | * | |
9443 | * Similarly with registers. If explored state has register type as invalid | |
9444 | * whereas register type in current state is meaningful, it means that | |
9445 | * the current state will reach 'bpf_exit' instruction safely | |
9446 | */ | |
f4d7e40a AS |
9447 | static bool func_states_equal(struct bpf_func_state *old, |
9448 | struct bpf_func_state *cur) | |
f1bca824 | 9449 | { |
f1174f77 EC |
9450 | struct idpair *idmap; |
9451 | bool ret = false; | |
f1bca824 AS |
9452 | int i; |
9453 | ||
f1174f77 EC |
9454 | idmap = kcalloc(ID_MAP_SIZE, sizeof(struct idpair), GFP_KERNEL); |
9455 | /* If we failed to allocate the idmap, just say it's not safe */ | |
9456 | if (!idmap) | |
1a0dc1ac | 9457 | return false; |
f1174f77 EC |
9458 | |
9459 | for (i = 0; i < MAX_BPF_REG; i++) { | |
1b688a19 | 9460 | if (!regsafe(&old->regs[i], &cur->regs[i], idmap)) |
f1174f77 | 9461 | goto out_free; |
f1bca824 AS |
9462 | } |
9463 | ||
638f5b90 AS |
9464 | if (!stacksafe(old, cur, idmap)) |
9465 | goto out_free; | |
fd978bf7 JS |
9466 | |
9467 | if (!refsafe(old, cur)) | |
9468 | goto out_free; | |
f1174f77 EC |
9469 | ret = true; |
9470 | out_free: | |
9471 | kfree(idmap); | |
9472 | return ret; | |
f1bca824 AS |
9473 | } |
9474 | ||
f4d7e40a AS |
9475 | static bool states_equal(struct bpf_verifier_env *env, |
9476 | struct bpf_verifier_state *old, | |
9477 | struct bpf_verifier_state *cur) | |
9478 | { | |
9479 | int i; | |
9480 | ||
9481 | if (old->curframe != cur->curframe) | |
9482 | return false; | |
9483 | ||
979d63d5 DB |
9484 | /* Verification state from speculative execution simulation |
9485 | * must never prune a non-speculative execution one. | |
9486 | */ | |
9487 | if (old->speculative && !cur->speculative) | |
9488 | return false; | |
9489 | ||
d83525ca AS |
9490 | if (old->active_spin_lock != cur->active_spin_lock) |
9491 | return false; | |
9492 | ||
f4d7e40a AS |
9493 | /* for states to be equal callsites have to be the same |
9494 | * and all frame states need to be equivalent | |
9495 | */ | |
9496 | for (i = 0; i <= old->curframe; i++) { | |
9497 | if (old->frame[i]->callsite != cur->frame[i]->callsite) | |
9498 | return false; | |
9499 | if (!func_states_equal(old->frame[i], cur->frame[i])) | |
9500 | return false; | |
9501 | } | |
9502 | return true; | |
9503 | } | |
9504 | ||
5327ed3d JW |
9505 | /* Return 0 if no propagation happened. Return negative error code if error |
9506 | * happened. Otherwise, return the propagated bit. | |
9507 | */ | |
55e7f3b5 JW |
9508 | static int propagate_liveness_reg(struct bpf_verifier_env *env, |
9509 | struct bpf_reg_state *reg, | |
9510 | struct bpf_reg_state *parent_reg) | |
9511 | { | |
5327ed3d JW |
9512 | u8 parent_flag = parent_reg->live & REG_LIVE_READ; |
9513 | u8 flag = reg->live & REG_LIVE_READ; | |
55e7f3b5 JW |
9514 | int err; |
9515 | ||
5327ed3d JW |
9516 | /* When comes here, read flags of PARENT_REG or REG could be any of |
9517 | * REG_LIVE_READ64, REG_LIVE_READ32, REG_LIVE_NONE. There is no need | |
9518 | * of propagation if PARENT_REG has strongest REG_LIVE_READ64. | |
9519 | */ | |
9520 | if (parent_flag == REG_LIVE_READ64 || | |
9521 | /* Or if there is no read flag from REG. */ | |
9522 | !flag || | |
9523 | /* Or if the read flag from REG is the same as PARENT_REG. */ | |
9524 | parent_flag == flag) | |
55e7f3b5 JW |
9525 | return 0; |
9526 | ||
5327ed3d | 9527 | err = mark_reg_read(env, reg, parent_reg, flag); |
55e7f3b5 JW |
9528 | if (err) |
9529 | return err; | |
9530 | ||
5327ed3d | 9531 | return flag; |
55e7f3b5 JW |
9532 | } |
9533 | ||
8e9cd9ce | 9534 | /* A write screens off any subsequent reads; but write marks come from the |
f4d7e40a AS |
9535 | * straight-line code between a state and its parent. When we arrive at an |
9536 | * equivalent state (jump target or such) we didn't arrive by the straight-line | |
9537 | * code, so read marks in the state must propagate to the parent regardless | |
9538 | * of the state's write marks. That's what 'parent == state->parent' comparison | |
679c782d | 9539 | * in mark_reg_read() is for. |
8e9cd9ce | 9540 | */ |
f4d7e40a AS |
9541 | static int propagate_liveness(struct bpf_verifier_env *env, |
9542 | const struct bpf_verifier_state *vstate, | |
9543 | struct bpf_verifier_state *vparent) | |
dc503a8a | 9544 | { |
3f8cafa4 | 9545 | struct bpf_reg_state *state_reg, *parent_reg; |
f4d7e40a | 9546 | struct bpf_func_state *state, *parent; |
3f8cafa4 | 9547 | int i, frame, err = 0; |
dc503a8a | 9548 | |
f4d7e40a AS |
9549 | if (vparent->curframe != vstate->curframe) { |
9550 | WARN(1, "propagate_live: parent frame %d current frame %d\n", | |
9551 | vparent->curframe, vstate->curframe); | |
9552 | return -EFAULT; | |
9553 | } | |
dc503a8a EC |
9554 | /* Propagate read liveness of registers... */ |
9555 | BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG); | |
83d16312 | 9556 | for (frame = 0; frame <= vstate->curframe; frame++) { |
3f8cafa4 JW |
9557 | parent = vparent->frame[frame]; |
9558 | state = vstate->frame[frame]; | |
9559 | parent_reg = parent->regs; | |
9560 | state_reg = state->regs; | |
83d16312 JK |
9561 | /* We don't need to worry about FP liveness, it's read-only */ |
9562 | for (i = frame < vstate->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) { | |
55e7f3b5 JW |
9563 | err = propagate_liveness_reg(env, &state_reg[i], |
9564 | &parent_reg[i]); | |
5327ed3d | 9565 | if (err < 0) |
3f8cafa4 | 9566 | return err; |
5327ed3d JW |
9567 | if (err == REG_LIVE_READ64) |
9568 | mark_insn_zext(env, &parent_reg[i]); | |
dc503a8a | 9569 | } |
f4d7e40a | 9570 | |
1b04aee7 | 9571 | /* Propagate stack slots. */ |
f4d7e40a AS |
9572 | for (i = 0; i < state->allocated_stack / BPF_REG_SIZE && |
9573 | i < parent->allocated_stack / BPF_REG_SIZE; i++) { | |
3f8cafa4 JW |
9574 | parent_reg = &parent->stack[i].spilled_ptr; |
9575 | state_reg = &state->stack[i].spilled_ptr; | |
55e7f3b5 JW |
9576 | err = propagate_liveness_reg(env, state_reg, |
9577 | parent_reg); | |
5327ed3d | 9578 | if (err < 0) |
3f8cafa4 | 9579 | return err; |
dc503a8a EC |
9580 | } |
9581 | } | |
5327ed3d | 9582 | return 0; |
dc503a8a EC |
9583 | } |
9584 | ||
a3ce685d AS |
9585 | /* find precise scalars in the previous equivalent state and |
9586 | * propagate them into the current state | |
9587 | */ | |
9588 | static int propagate_precision(struct bpf_verifier_env *env, | |
9589 | const struct bpf_verifier_state *old) | |
9590 | { | |
9591 | struct bpf_reg_state *state_reg; | |
9592 | struct bpf_func_state *state; | |
9593 | int i, err = 0; | |
9594 | ||
9595 | state = old->frame[old->curframe]; | |
9596 | state_reg = state->regs; | |
9597 | for (i = 0; i < BPF_REG_FP; i++, state_reg++) { | |
9598 | if (state_reg->type != SCALAR_VALUE || | |
9599 | !state_reg->precise) | |
9600 | continue; | |
9601 | if (env->log.level & BPF_LOG_LEVEL2) | |
9602 | verbose(env, "propagating r%d\n", i); | |
9603 | err = mark_chain_precision(env, i); | |
9604 | if (err < 0) | |
9605 | return err; | |
9606 | } | |
9607 | ||
9608 | for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) { | |
9609 | if (state->stack[i].slot_type[0] != STACK_SPILL) | |
9610 | continue; | |
9611 | state_reg = &state->stack[i].spilled_ptr; | |
9612 | if (state_reg->type != SCALAR_VALUE || | |
9613 | !state_reg->precise) | |
9614 | continue; | |
9615 | if (env->log.level & BPF_LOG_LEVEL2) | |
9616 | verbose(env, "propagating fp%d\n", | |
9617 | (-i - 1) * BPF_REG_SIZE); | |
9618 | err = mark_chain_precision_stack(env, i); | |
9619 | if (err < 0) | |
9620 | return err; | |
9621 | } | |
9622 | return 0; | |
9623 | } | |
9624 | ||
2589726d AS |
9625 | static bool states_maybe_looping(struct bpf_verifier_state *old, |
9626 | struct bpf_verifier_state *cur) | |
9627 | { | |
9628 | struct bpf_func_state *fold, *fcur; | |
9629 | int i, fr = cur->curframe; | |
9630 | ||
9631 | if (old->curframe != fr) | |
9632 | return false; | |
9633 | ||
9634 | fold = old->frame[fr]; | |
9635 | fcur = cur->frame[fr]; | |
9636 | for (i = 0; i < MAX_BPF_REG; i++) | |
9637 | if (memcmp(&fold->regs[i], &fcur->regs[i], | |
9638 | offsetof(struct bpf_reg_state, parent))) | |
9639 | return false; | |
9640 | return true; | |
9641 | } | |
9642 | ||
9643 | ||
58e2af8b | 9644 | static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) |
f1bca824 | 9645 | { |
58e2af8b | 9646 | struct bpf_verifier_state_list *new_sl; |
9f4686c4 | 9647 | struct bpf_verifier_state_list *sl, **pprev; |
679c782d | 9648 | struct bpf_verifier_state *cur = env->cur_state, *new; |
ceefbc96 | 9649 | int i, j, err, states_cnt = 0; |
10d274e8 | 9650 | bool add_new_state = env->test_state_freq ? true : false; |
f1bca824 | 9651 | |
b5dc0163 | 9652 | cur->last_insn_idx = env->prev_insn_idx; |
a8f500af | 9653 | if (!env->insn_aux_data[insn_idx].prune_point) |
f1bca824 AS |
9654 | /* this 'insn_idx' instruction wasn't marked, so we will not |
9655 | * be doing state search here | |
9656 | */ | |
9657 | return 0; | |
9658 | ||
2589726d AS |
9659 | /* bpf progs typically have pruning point every 4 instructions |
9660 | * http://vger.kernel.org/bpfconf2019.html#session-1 | |
9661 | * Do not add new state for future pruning if the verifier hasn't seen | |
9662 | * at least 2 jumps and at least 8 instructions. | |
9663 | * This heuristics helps decrease 'total_states' and 'peak_states' metric. | |
9664 | * In tests that amounts to up to 50% reduction into total verifier | |
9665 | * memory consumption and 20% verifier time speedup. | |
9666 | */ | |
9667 | if (env->jmps_processed - env->prev_jmps_processed >= 2 && | |
9668 | env->insn_processed - env->prev_insn_processed >= 8) | |
9669 | add_new_state = true; | |
9670 | ||
a8f500af AS |
9671 | pprev = explored_state(env, insn_idx); |
9672 | sl = *pprev; | |
9673 | ||
9242b5f5 AS |
9674 | clean_live_states(env, insn_idx, cur); |
9675 | ||
a8f500af | 9676 | while (sl) { |
dc2a4ebc AS |
9677 | states_cnt++; |
9678 | if (sl->state.insn_idx != insn_idx) | |
9679 | goto next; | |
2589726d AS |
9680 | if (sl->state.branches) { |
9681 | if (states_maybe_looping(&sl->state, cur) && | |
9682 | states_equal(env, &sl->state, cur)) { | |
9683 | verbose_linfo(env, insn_idx, "; "); | |
9684 | verbose(env, "infinite loop detected at insn %d\n", insn_idx); | |
9685 | return -EINVAL; | |
9686 | } | |
9687 | /* if the verifier is processing a loop, avoid adding new state | |
9688 | * too often, since different loop iterations have distinct | |
9689 | * states and may not help future pruning. | |
9690 | * This threshold shouldn't be too low to make sure that | |
9691 | * a loop with large bound will be rejected quickly. | |
9692 | * The most abusive loop will be: | |
9693 | * r1 += 1 | |
9694 | * if r1 < 1000000 goto pc-2 | |
9695 | * 1M insn_procssed limit / 100 == 10k peak states. | |
9696 | * This threshold shouldn't be too high either, since states | |
9697 | * at the end of the loop are likely to be useful in pruning. | |
9698 | */ | |
9699 | if (env->jmps_processed - env->prev_jmps_processed < 20 && | |
9700 | env->insn_processed - env->prev_insn_processed < 100) | |
9701 | add_new_state = false; | |
9702 | goto miss; | |
9703 | } | |
638f5b90 | 9704 | if (states_equal(env, &sl->state, cur)) { |
9f4686c4 | 9705 | sl->hit_cnt++; |
f1bca824 | 9706 | /* reached equivalent register/stack state, |
dc503a8a EC |
9707 | * prune the search. |
9708 | * Registers read by the continuation are read by us. | |
8e9cd9ce EC |
9709 | * If we have any write marks in env->cur_state, they |
9710 | * will prevent corresponding reads in the continuation | |
9711 | * from reaching our parent (an explored_state). Our | |
9712 | * own state will get the read marks recorded, but | |
9713 | * they'll be immediately forgotten as we're pruning | |
9714 | * this state and will pop a new one. | |
f1bca824 | 9715 | */ |
f4d7e40a | 9716 | err = propagate_liveness(env, &sl->state, cur); |
a3ce685d AS |
9717 | |
9718 | /* if previous state reached the exit with precision and | |
9719 | * current state is equivalent to it (except precsion marks) | |
9720 | * the precision needs to be propagated back in | |
9721 | * the current state. | |
9722 | */ | |
9723 | err = err ? : push_jmp_history(env, cur); | |
9724 | err = err ? : propagate_precision(env, &sl->state); | |
f4d7e40a AS |
9725 | if (err) |
9726 | return err; | |
f1bca824 | 9727 | return 1; |
dc503a8a | 9728 | } |
2589726d AS |
9729 | miss: |
9730 | /* when new state is not going to be added do not increase miss count. | |
9731 | * Otherwise several loop iterations will remove the state | |
9732 | * recorded earlier. The goal of these heuristics is to have | |
9733 | * states from some iterations of the loop (some in the beginning | |
9734 | * and some at the end) to help pruning. | |
9735 | */ | |
9736 | if (add_new_state) | |
9737 | sl->miss_cnt++; | |
9f4686c4 AS |
9738 | /* heuristic to determine whether this state is beneficial |
9739 | * to keep checking from state equivalence point of view. | |
9740 | * Higher numbers increase max_states_per_insn and verification time, | |
9741 | * but do not meaningfully decrease insn_processed. | |
9742 | */ | |
9743 | if (sl->miss_cnt > sl->hit_cnt * 3 + 3) { | |
9744 | /* the state is unlikely to be useful. Remove it to | |
9745 | * speed up verification | |
9746 | */ | |
9747 | *pprev = sl->next; | |
9748 | if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE) { | |
2589726d AS |
9749 | u32 br = sl->state.branches; |
9750 | ||
9751 | WARN_ONCE(br, | |
9752 | "BUG live_done but branches_to_explore %d\n", | |
9753 | br); | |
9f4686c4 AS |
9754 | free_verifier_state(&sl->state, false); |
9755 | kfree(sl); | |
9756 | env->peak_states--; | |
9757 | } else { | |
9758 | /* cannot free this state, since parentage chain may | |
9759 | * walk it later. Add it for free_list instead to | |
9760 | * be freed at the end of verification | |
9761 | */ | |
9762 | sl->next = env->free_list; | |
9763 | env->free_list = sl; | |
9764 | } | |
9765 | sl = *pprev; | |
9766 | continue; | |
9767 | } | |
dc2a4ebc | 9768 | next: |
9f4686c4 AS |
9769 | pprev = &sl->next; |
9770 | sl = *pprev; | |
f1bca824 AS |
9771 | } |
9772 | ||
06ee7115 AS |
9773 | if (env->max_states_per_insn < states_cnt) |
9774 | env->max_states_per_insn = states_cnt; | |
9775 | ||
2c78ee89 | 9776 | if (!env->bpf_capable && states_cnt > BPF_COMPLEXITY_LIMIT_STATES) |
b5dc0163 | 9777 | return push_jmp_history(env, cur); |
ceefbc96 | 9778 | |
2589726d | 9779 | if (!add_new_state) |
b5dc0163 | 9780 | return push_jmp_history(env, cur); |
ceefbc96 | 9781 | |
2589726d AS |
9782 | /* There were no equivalent states, remember the current one. |
9783 | * Technically the current state is not proven to be safe yet, | |
f4d7e40a | 9784 | * but it will either reach outer most bpf_exit (which means it's safe) |
2589726d | 9785 | * or it will be rejected. When there are no loops the verifier won't be |
f4d7e40a | 9786 | * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx) |
2589726d AS |
9787 | * again on the way to bpf_exit. |
9788 | * When looping the sl->state.branches will be > 0 and this state | |
9789 | * will not be considered for equivalence until branches == 0. | |
f1bca824 | 9790 | */ |
638f5b90 | 9791 | new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL); |
f1bca824 AS |
9792 | if (!new_sl) |
9793 | return -ENOMEM; | |
06ee7115 AS |
9794 | env->total_states++; |
9795 | env->peak_states++; | |
2589726d AS |
9796 | env->prev_jmps_processed = env->jmps_processed; |
9797 | env->prev_insn_processed = env->insn_processed; | |
f1bca824 AS |
9798 | |
9799 | /* add new state to the head of linked list */ | |
679c782d EC |
9800 | new = &new_sl->state; |
9801 | err = copy_verifier_state(new, cur); | |
1969db47 | 9802 | if (err) { |
679c782d | 9803 | free_verifier_state(new, false); |
1969db47 AS |
9804 | kfree(new_sl); |
9805 | return err; | |
9806 | } | |
dc2a4ebc | 9807 | new->insn_idx = insn_idx; |
2589726d AS |
9808 | WARN_ONCE(new->branches != 1, |
9809 | "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches, insn_idx); | |
b5dc0163 | 9810 | |
2589726d | 9811 | cur->parent = new; |
b5dc0163 AS |
9812 | cur->first_insn_idx = insn_idx; |
9813 | clear_jmp_history(cur); | |
5d839021 AS |
9814 | new_sl->next = *explored_state(env, insn_idx); |
9815 | *explored_state(env, insn_idx) = new_sl; | |
7640ead9 JK |
9816 | /* connect new state to parentage chain. Current frame needs all |
9817 | * registers connected. Only r6 - r9 of the callers are alive (pushed | |
9818 | * to the stack implicitly by JITs) so in callers' frames connect just | |
9819 | * r6 - r9 as an optimization. Callers will have r1 - r5 connected to | |
9820 | * the state of the call instruction (with WRITTEN set), and r0 comes | |
9821 | * from callee with its full parentage chain, anyway. | |
9822 | */ | |
8e9cd9ce EC |
9823 | /* clear write marks in current state: the writes we did are not writes |
9824 | * our child did, so they don't screen off its reads from us. | |
9825 | * (There are no read marks in current state, because reads always mark | |
9826 | * their parent and current state never has children yet. Only | |
9827 | * explored_states can get read marks.) | |
9828 | */ | |
eea1c227 AS |
9829 | for (j = 0; j <= cur->curframe; j++) { |
9830 | for (i = j < cur->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) | |
9831 | cur->frame[j]->regs[i].parent = &new->frame[j]->regs[i]; | |
9832 | for (i = 0; i < BPF_REG_FP; i++) | |
9833 | cur->frame[j]->regs[i].live = REG_LIVE_NONE; | |
9834 | } | |
f4d7e40a AS |
9835 | |
9836 | /* all stack frames are accessible from callee, clear them all */ | |
9837 | for (j = 0; j <= cur->curframe; j++) { | |
9838 | struct bpf_func_state *frame = cur->frame[j]; | |
679c782d | 9839 | struct bpf_func_state *newframe = new->frame[j]; |
f4d7e40a | 9840 | |
679c782d | 9841 | for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++) { |
cc2b14d5 | 9842 | frame->stack[i].spilled_ptr.live = REG_LIVE_NONE; |
679c782d EC |
9843 | frame->stack[i].spilled_ptr.parent = |
9844 | &newframe->stack[i].spilled_ptr; | |
9845 | } | |
f4d7e40a | 9846 | } |
f1bca824 AS |
9847 | return 0; |
9848 | } | |
9849 | ||
c64b7983 JS |
9850 | /* Return true if it's OK to have the same insn return a different type. */ |
9851 | static bool reg_type_mismatch_ok(enum bpf_reg_type type) | |
9852 | { | |
9853 | switch (type) { | |
9854 | case PTR_TO_CTX: | |
9855 | case PTR_TO_SOCKET: | |
9856 | case PTR_TO_SOCKET_OR_NULL: | |
46f8bc92 MKL |
9857 | case PTR_TO_SOCK_COMMON: |
9858 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
655a51e5 MKL |
9859 | case PTR_TO_TCP_SOCK: |
9860 | case PTR_TO_TCP_SOCK_OR_NULL: | |
fada7fdc | 9861 | case PTR_TO_XDP_SOCK: |
2a02759e | 9862 | case PTR_TO_BTF_ID: |
b121b341 | 9863 | case PTR_TO_BTF_ID_OR_NULL: |
c64b7983 JS |
9864 | return false; |
9865 | default: | |
9866 | return true; | |
9867 | } | |
9868 | } | |
9869 | ||
9870 | /* If an instruction was previously used with particular pointer types, then we | |
9871 | * need to be careful to avoid cases such as the below, where it may be ok | |
9872 | * for one branch accessing the pointer, but not ok for the other branch: | |
9873 | * | |
9874 | * R1 = sock_ptr | |
9875 | * goto X; | |
9876 | * ... | |
9877 | * R1 = some_other_valid_ptr; | |
9878 | * goto X; | |
9879 | * ... | |
9880 | * R2 = *(u32 *)(R1 + 0); | |
9881 | */ | |
9882 | static bool reg_type_mismatch(enum bpf_reg_type src, enum bpf_reg_type prev) | |
9883 | { | |
9884 | return src != prev && (!reg_type_mismatch_ok(src) || | |
9885 | !reg_type_mismatch_ok(prev)); | |
9886 | } | |
9887 | ||
58e2af8b | 9888 | static int do_check(struct bpf_verifier_env *env) |
17a52670 | 9889 | { |
6f8a57cc | 9890 | bool pop_log = !(env->log.level & BPF_LOG_LEVEL2); |
51c39bb1 | 9891 | struct bpf_verifier_state *state = env->cur_state; |
17a52670 | 9892 | struct bpf_insn *insns = env->prog->insnsi; |
638f5b90 | 9893 | struct bpf_reg_state *regs; |
06ee7115 | 9894 | int insn_cnt = env->prog->len; |
17a52670 | 9895 | bool do_print_state = false; |
b5dc0163 | 9896 | int prev_insn_idx = -1; |
17a52670 | 9897 | |
17a52670 AS |
9898 | for (;;) { |
9899 | struct bpf_insn *insn; | |
9900 | u8 class; | |
9901 | int err; | |
9902 | ||
b5dc0163 | 9903 | env->prev_insn_idx = prev_insn_idx; |
c08435ec | 9904 | if (env->insn_idx >= insn_cnt) { |
61bd5218 | 9905 | verbose(env, "invalid insn idx %d insn_cnt %d\n", |
c08435ec | 9906 | env->insn_idx, insn_cnt); |
17a52670 AS |
9907 | return -EFAULT; |
9908 | } | |
9909 | ||
c08435ec | 9910 | insn = &insns[env->insn_idx]; |
17a52670 AS |
9911 | class = BPF_CLASS(insn->code); |
9912 | ||
06ee7115 | 9913 | if (++env->insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) { |
61bd5218 JK |
9914 | verbose(env, |
9915 | "BPF program is too large. Processed %d insn\n", | |
06ee7115 | 9916 | env->insn_processed); |
17a52670 AS |
9917 | return -E2BIG; |
9918 | } | |
9919 | ||
c08435ec | 9920 | err = is_state_visited(env, env->insn_idx); |
f1bca824 AS |
9921 | if (err < 0) |
9922 | return err; | |
9923 | if (err == 1) { | |
9924 | /* found equivalent state, can prune the search */ | |
06ee7115 | 9925 | if (env->log.level & BPF_LOG_LEVEL) { |
f1bca824 | 9926 | if (do_print_state) |
979d63d5 DB |
9927 | verbose(env, "\nfrom %d to %d%s: safe\n", |
9928 | env->prev_insn_idx, env->insn_idx, | |
9929 | env->cur_state->speculative ? | |
9930 | " (speculative execution)" : ""); | |
f1bca824 | 9931 | else |
c08435ec | 9932 | verbose(env, "%d: safe\n", env->insn_idx); |
f1bca824 AS |
9933 | } |
9934 | goto process_bpf_exit; | |
9935 | } | |
9936 | ||
c3494801 AS |
9937 | if (signal_pending(current)) |
9938 | return -EAGAIN; | |
9939 | ||
3c2ce60b DB |
9940 | if (need_resched()) |
9941 | cond_resched(); | |
9942 | ||
06ee7115 AS |
9943 | if (env->log.level & BPF_LOG_LEVEL2 || |
9944 | (env->log.level & BPF_LOG_LEVEL && do_print_state)) { | |
9945 | if (env->log.level & BPF_LOG_LEVEL2) | |
c08435ec | 9946 | verbose(env, "%d:", env->insn_idx); |
c5fc9692 | 9947 | else |
979d63d5 DB |
9948 | verbose(env, "\nfrom %d to %d%s:", |
9949 | env->prev_insn_idx, env->insn_idx, | |
9950 | env->cur_state->speculative ? | |
9951 | " (speculative execution)" : ""); | |
f4d7e40a | 9952 | print_verifier_state(env, state->frame[state->curframe]); |
17a52670 AS |
9953 | do_print_state = false; |
9954 | } | |
9955 | ||
06ee7115 | 9956 | if (env->log.level & BPF_LOG_LEVEL) { |
7105e828 DB |
9957 | const struct bpf_insn_cbs cbs = { |
9958 | .cb_print = verbose, | |
abe08840 | 9959 | .private_data = env, |
7105e828 DB |
9960 | }; |
9961 | ||
c08435ec DB |
9962 | verbose_linfo(env, env->insn_idx, "; "); |
9963 | verbose(env, "%d: ", env->insn_idx); | |
abe08840 | 9964 | print_bpf_insn(&cbs, insn, env->allow_ptr_leaks); |
17a52670 AS |
9965 | } |
9966 | ||
cae1927c | 9967 | if (bpf_prog_is_dev_bound(env->prog->aux)) { |
c08435ec DB |
9968 | err = bpf_prog_offload_verify_insn(env, env->insn_idx, |
9969 | env->prev_insn_idx); | |
cae1927c JK |
9970 | if (err) |
9971 | return err; | |
9972 | } | |
13a27dfc | 9973 | |
638f5b90 | 9974 | regs = cur_regs(env); |
51c39bb1 | 9975 | env->insn_aux_data[env->insn_idx].seen = env->pass_cnt; |
b5dc0163 | 9976 | prev_insn_idx = env->insn_idx; |
fd978bf7 | 9977 | |
17a52670 | 9978 | if (class == BPF_ALU || class == BPF_ALU64) { |
1be7f75d | 9979 | err = check_alu_op(env, insn); |
17a52670 AS |
9980 | if (err) |
9981 | return err; | |
9982 | ||
9983 | } else if (class == BPF_LDX) { | |
3df126f3 | 9984 | enum bpf_reg_type *prev_src_type, src_reg_type; |
9bac3d6d AS |
9985 | |
9986 | /* check for reserved fields is already done */ | |
9987 | ||
17a52670 | 9988 | /* check src operand */ |
dc503a8a | 9989 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
9990 | if (err) |
9991 | return err; | |
9992 | ||
dc503a8a | 9993 | err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); |
17a52670 AS |
9994 | if (err) |
9995 | return err; | |
9996 | ||
725f9dcd AS |
9997 | src_reg_type = regs[insn->src_reg].type; |
9998 | ||
17a52670 AS |
9999 | /* check that memory (src_reg + off) is readable, |
10000 | * the state of dst_reg will be updated by this func | |
10001 | */ | |
c08435ec DB |
10002 | err = check_mem_access(env, env->insn_idx, insn->src_reg, |
10003 | insn->off, BPF_SIZE(insn->code), | |
10004 | BPF_READ, insn->dst_reg, false); | |
17a52670 AS |
10005 | if (err) |
10006 | return err; | |
10007 | ||
c08435ec | 10008 | prev_src_type = &env->insn_aux_data[env->insn_idx].ptr_type; |
3df126f3 JK |
10009 | |
10010 | if (*prev_src_type == NOT_INIT) { | |
9bac3d6d AS |
10011 | /* saw a valid insn |
10012 | * dst_reg = *(u32 *)(src_reg + off) | |
3df126f3 | 10013 | * save type to validate intersecting paths |
9bac3d6d | 10014 | */ |
3df126f3 | 10015 | *prev_src_type = src_reg_type; |
9bac3d6d | 10016 | |
c64b7983 | 10017 | } else if (reg_type_mismatch(src_reg_type, *prev_src_type)) { |
9bac3d6d AS |
10018 | /* ABuser program is trying to use the same insn |
10019 | * dst_reg = *(u32*) (src_reg + off) | |
10020 | * with different pointer types: | |
10021 | * src_reg == ctx in one branch and | |
10022 | * src_reg == stack|map in some other branch. | |
10023 | * Reject it. | |
10024 | */ | |
61bd5218 | 10025 | verbose(env, "same insn cannot be used with different pointers\n"); |
9bac3d6d AS |
10026 | return -EINVAL; |
10027 | } | |
10028 | ||
17a52670 | 10029 | } else if (class == BPF_STX) { |
3df126f3 | 10030 | enum bpf_reg_type *prev_dst_type, dst_reg_type; |
d691f9e8 | 10031 | |
91c960b0 BJ |
10032 | if (BPF_MODE(insn->code) == BPF_ATOMIC) { |
10033 | err = check_atomic(env, env->insn_idx, insn); | |
17a52670 AS |
10034 | if (err) |
10035 | return err; | |
c08435ec | 10036 | env->insn_idx++; |
17a52670 AS |
10037 | continue; |
10038 | } | |
10039 | ||
5ca419f2 BJ |
10040 | if (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0) { |
10041 | verbose(env, "BPF_STX uses reserved fields\n"); | |
10042 | return -EINVAL; | |
10043 | } | |
10044 | ||
17a52670 | 10045 | /* check src1 operand */ |
dc503a8a | 10046 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
10047 | if (err) |
10048 | return err; | |
10049 | /* check src2 operand */ | |
dc503a8a | 10050 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
10051 | if (err) |
10052 | return err; | |
10053 | ||
d691f9e8 AS |
10054 | dst_reg_type = regs[insn->dst_reg].type; |
10055 | ||
17a52670 | 10056 | /* check that memory (dst_reg + off) is writeable */ |
c08435ec DB |
10057 | err = check_mem_access(env, env->insn_idx, insn->dst_reg, |
10058 | insn->off, BPF_SIZE(insn->code), | |
10059 | BPF_WRITE, insn->src_reg, false); | |
17a52670 AS |
10060 | if (err) |
10061 | return err; | |
10062 | ||
c08435ec | 10063 | prev_dst_type = &env->insn_aux_data[env->insn_idx].ptr_type; |
3df126f3 JK |
10064 | |
10065 | if (*prev_dst_type == NOT_INIT) { | |
10066 | *prev_dst_type = dst_reg_type; | |
c64b7983 | 10067 | } else if (reg_type_mismatch(dst_reg_type, *prev_dst_type)) { |
61bd5218 | 10068 | verbose(env, "same insn cannot be used with different pointers\n"); |
d691f9e8 AS |
10069 | return -EINVAL; |
10070 | } | |
10071 | ||
17a52670 AS |
10072 | } else if (class == BPF_ST) { |
10073 | if (BPF_MODE(insn->code) != BPF_MEM || | |
10074 | insn->src_reg != BPF_REG_0) { | |
61bd5218 | 10075 | verbose(env, "BPF_ST uses reserved fields\n"); |
17a52670 AS |
10076 | return -EINVAL; |
10077 | } | |
10078 | /* check src operand */ | |
dc503a8a | 10079 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
10080 | if (err) |
10081 | return err; | |
10082 | ||
f37a8cb8 | 10083 | if (is_ctx_reg(env, insn->dst_reg)) { |
9d2be44a | 10084 | verbose(env, "BPF_ST stores into R%d %s is not allowed\n", |
2a159c6f DB |
10085 | insn->dst_reg, |
10086 | reg_type_str[reg_state(env, insn->dst_reg)->type]); | |
f37a8cb8 DB |
10087 | return -EACCES; |
10088 | } | |
10089 | ||
17a52670 | 10090 | /* check that memory (dst_reg + off) is writeable */ |
c08435ec DB |
10091 | err = check_mem_access(env, env->insn_idx, insn->dst_reg, |
10092 | insn->off, BPF_SIZE(insn->code), | |
10093 | BPF_WRITE, -1, false); | |
17a52670 AS |
10094 | if (err) |
10095 | return err; | |
10096 | ||
092ed096 | 10097 | } else if (class == BPF_JMP || class == BPF_JMP32) { |
17a52670 AS |
10098 | u8 opcode = BPF_OP(insn->code); |
10099 | ||
2589726d | 10100 | env->jmps_processed++; |
17a52670 AS |
10101 | if (opcode == BPF_CALL) { |
10102 | if (BPF_SRC(insn->code) != BPF_K || | |
10103 | insn->off != 0 || | |
f4d7e40a AS |
10104 | (insn->src_reg != BPF_REG_0 && |
10105 | insn->src_reg != BPF_PSEUDO_CALL) || | |
092ed096 JW |
10106 | insn->dst_reg != BPF_REG_0 || |
10107 | class == BPF_JMP32) { | |
61bd5218 | 10108 | verbose(env, "BPF_CALL uses reserved fields\n"); |
17a52670 AS |
10109 | return -EINVAL; |
10110 | } | |
10111 | ||
d83525ca AS |
10112 | if (env->cur_state->active_spin_lock && |
10113 | (insn->src_reg == BPF_PSEUDO_CALL || | |
10114 | insn->imm != BPF_FUNC_spin_unlock)) { | |
10115 | verbose(env, "function calls are not allowed while holding a lock\n"); | |
10116 | return -EINVAL; | |
10117 | } | |
f4d7e40a | 10118 | if (insn->src_reg == BPF_PSEUDO_CALL) |
c08435ec | 10119 | err = check_func_call(env, insn, &env->insn_idx); |
f4d7e40a | 10120 | else |
c08435ec | 10121 | err = check_helper_call(env, insn->imm, env->insn_idx); |
17a52670 AS |
10122 | if (err) |
10123 | return err; | |
10124 | ||
10125 | } else if (opcode == BPF_JA) { | |
10126 | if (BPF_SRC(insn->code) != BPF_K || | |
10127 | insn->imm != 0 || | |
10128 | insn->src_reg != BPF_REG_0 || | |
092ed096 JW |
10129 | insn->dst_reg != BPF_REG_0 || |
10130 | class == BPF_JMP32) { | |
61bd5218 | 10131 | verbose(env, "BPF_JA uses reserved fields\n"); |
17a52670 AS |
10132 | return -EINVAL; |
10133 | } | |
10134 | ||
c08435ec | 10135 | env->insn_idx += insn->off + 1; |
17a52670 AS |
10136 | continue; |
10137 | ||
10138 | } else if (opcode == BPF_EXIT) { | |
10139 | if (BPF_SRC(insn->code) != BPF_K || | |
10140 | insn->imm != 0 || | |
10141 | insn->src_reg != BPF_REG_0 || | |
092ed096 JW |
10142 | insn->dst_reg != BPF_REG_0 || |
10143 | class == BPF_JMP32) { | |
61bd5218 | 10144 | verbose(env, "BPF_EXIT uses reserved fields\n"); |
17a52670 AS |
10145 | return -EINVAL; |
10146 | } | |
10147 | ||
d83525ca AS |
10148 | if (env->cur_state->active_spin_lock) { |
10149 | verbose(env, "bpf_spin_unlock is missing\n"); | |
10150 | return -EINVAL; | |
10151 | } | |
10152 | ||
f4d7e40a AS |
10153 | if (state->curframe) { |
10154 | /* exit from nested function */ | |
c08435ec | 10155 | err = prepare_func_exit(env, &env->insn_idx); |
f4d7e40a AS |
10156 | if (err) |
10157 | return err; | |
10158 | do_print_state = true; | |
10159 | continue; | |
10160 | } | |
10161 | ||
fd978bf7 JS |
10162 | err = check_reference_leak(env); |
10163 | if (err) | |
10164 | return err; | |
10165 | ||
390ee7e2 AS |
10166 | err = check_return_code(env); |
10167 | if (err) | |
10168 | return err; | |
f1bca824 | 10169 | process_bpf_exit: |
2589726d | 10170 | update_branch_counts(env, env->cur_state); |
b5dc0163 | 10171 | err = pop_stack(env, &prev_insn_idx, |
6f8a57cc | 10172 | &env->insn_idx, pop_log); |
638f5b90 AS |
10173 | if (err < 0) { |
10174 | if (err != -ENOENT) | |
10175 | return err; | |
17a52670 AS |
10176 | break; |
10177 | } else { | |
10178 | do_print_state = true; | |
10179 | continue; | |
10180 | } | |
10181 | } else { | |
c08435ec | 10182 | err = check_cond_jmp_op(env, insn, &env->insn_idx); |
17a52670 AS |
10183 | if (err) |
10184 | return err; | |
10185 | } | |
10186 | } else if (class == BPF_LD) { | |
10187 | u8 mode = BPF_MODE(insn->code); | |
10188 | ||
10189 | if (mode == BPF_ABS || mode == BPF_IND) { | |
ddd872bc AS |
10190 | err = check_ld_abs(env, insn); |
10191 | if (err) | |
10192 | return err; | |
10193 | ||
17a52670 AS |
10194 | } else if (mode == BPF_IMM) { |
10195 | err = check_ld_imm(env, insn); | |
10196 | if (err) | |
10197 | return err; | |
10198 | ||
c08435ec | 10199 | env->insn_idx++; |
51c39bb1 | 10200 | env->insn_aux_data[env->insn_idx].seen = env->pass_cnt; |
17a52670 | 10201 | } else { |
61bd5218 | 10202 | verbose(env, "invalid BPF_LD mode\n"); |
17a52670 AS |
10203 | return -EINVAL; |
10204 | } | |
10205 | } else { | |
61bd5218 | 10206 | verbose(env, "unknown insn class %d\n", class); |
17a52670 AS |
10207 | return -EINVAL; |
10208 | } | |
10209 | ||
c08435ec | 10210 | env->insn_idx++; |
17a52670 AS |
10211 | } |
10212 | ||
10213 | return 0; | |
10214 | } | |
10215 | ||
541c3bad AN |
10216 | static int find_btf_percpu_datasec(struct btf *btf) |
10217 | { | |
10218 | const struct btf_type *t; | |
10219 | const char *tname; | |
10220 | int i, n; | |
10221 | ||
10222 | /* | |
10223 | * Both vmlinux and module each have their own ".data..percpu" | |
10224 | * DATASECs in BTF. So for module's case, we need to skip vmlinux BTF | |
10225 | * types to look at only module's own BTF types. | |
10226 | */ | |
10227 | n = btf_nr_types(btf); | |
10228 | if (btf_is_module(btf)) | |
10229 | i = btf_nr_types(btf_vmlinux); | |
10230 | else | |
10231 | i = 1; | |
10232 | ||
10233 | for(; i < n; i++) { | |
10234 | t = btf_type_by_id(btf, i); | |
10235 | if (BTF_INFO_KIND(t->info) != BTF_KIND_DATASEC) | |
10236 | continue; | |
10237 | ||
10238 | tname = btf_name_by_offset(btf, t->name_off); | |
10239 | if (!strcmp(tname, ".data..percpu")) | |
10240 | return i; | |
10241 | } | |
10242 | ||
10243 | return -ENOENT; | |
10244 | } | |
10245 | ||
4976b718 HL |
10246 | /* replace pseudo btf_id with kernel symbol address */ |
10247 | static int check_pseudo_btf_id(struct bpf_verifier_env *env, | |
10248 | struct bpf_insn *insn, | |
10249 | struct bpf_insn_aux_data *aux) | |
10250 | { | |
eaa6bcb7 HL |
10251 | const struct btf_var_secinfo *vsi; |
10252 | const struct btf_type *datasec; | |
541c3bad | 10253 | struct btf_mod_pair *btf_mod; |
4976b718 HL |
10254 | const struct btf_type *t; |
10255 | const char *sym_name; | |
eaa6bcb7 | 10256 | bool percpu = false; |
f16e6313 | 10257 | u32 type, id = insn->imm; |
541c3bad | 10258 | struct btf *btf; |
f16e6313 | 10259 | s32 datasec_id; |
4976b718 | 10260 | u64 addr; |
541c3bad | 10261 | int i, btf_fd, err; |
4976b718 | 10262 | |
541c3bad AN |
10263 | btf_fd = insn[1].imm; |
10264 | if (btf_fd) { | |
10265 | btf = btf_get_by_fd(btf_fd); | |
10266 | if (IS_ERR(btf)) { | |
10267 | verbose(env, "invalid module BTF object FD specified.\n"); | |
10268 | return -EINVAL; | |
10269 | } | |
10270 | } else { | |
10271 | if (!btf_vmlinux) { | |
10272 | verbose(env, "kernel is missing BTF, make sure CONFIG_DEBUG_INFO_BTF=y is specified in Kconfig.\n"); | |
10273 | return -EINVAL; | |
10274 | } | |
10275 | btf = btf_vmlinux; | |
10276 | btf_get(btf); | |
4976b718 HL |
10277 | } |
10278 | ||
541c3bad | 10279 | t = btf_type_by_id(btf, id); |
4976b718 HL |
10280 | if (!t) { |
10281 | verbose(env, "ldimm64 insn specifies invalid btf_id %d.\n", id); | |
541c3bad AN |
10282 | err = -ENOENT; |
10283 | goto err_put; | |
4976b718 HL |
10284 | } |
10285 | ||
10286 | if (!btf_type_is_var(t)) { | |
541c3bad AN |
10287 | verbose(env, "pseudo btf_id %d in ldimm64 isn't KIND_VAR.\n", id); |
10288 | err = -EINVAL; | |
10289 | goto err_put; | |
4976b718 HL |
10290 | } |
10291 | ||
541c3bad | 10292 | sym_name = btf_name_by_offset(btf, t->name_off); |
4976b718 HL |
10293 | addr = kallsyms_lookup_name(sym_name); |
10294 | if (!addr) { | |
10295 | verbose(env, "ldimm64 failed to find the address for kernel symbol '%s'.\n", | |
10296 | sym_name); | |
541c3bad AN |
10297 | err = -ENOENT; |
10298 | goto err_put; | |
4976b718 HL |
10299 | } |
10300 | ||
541c3bad | 10301 | datasec_id = find_btf_percpu_datasec(btf); |
eaa6bcb7 | 10302 | if (datasec_id > 0) { |
541c3bad | 10303 | datasec = btf_type_by_id(btf, datasec_id); |
eaa6bcb7 HL |
10304 | for_each_vsi(i, datasec, vsi) { |
10305 | if (vsi->type == id) { | |
10306 | percpu = true; | |
10307 | break; | |
10308 | } | |
10309 | } | |
10310 | } | |
10311 | ||
4976b718 HL |
10312 | insn[0].imm = (u32)addr; |
10313 | insn[1].imm = addr >> 32; | |
10314 | ||
10315 | type = t->type; | |
541c3bad | 10316 | t = btf_type_skip_modifiers(btf, type, NULL); |
eaa6bcb7 HL |
10317 | if (percpu) { |
10318 | aux->btf_var.reg_type = PTR_TO_PERCPU_BTF_ID; | |
541c3bad | 10319 | aux->btf_var.btf = btf; |
eaa6bcb7 HL |
10320 | aux->btf_var.btf_id = type; |
10321 | } else if (!btf_type_is_struct(t)) { | |
4976b718 HL |
10322 | const struct btf_type *ret; |
10323 | const char *tname; | |
10324 | u32 tsize; | |
10325 | ||
10326 | /* resolve the type size of ksym. */ | |
541c3bad | 10327 | ret = btf_resolve_size(btf, t, &tsize); |
4976b718 | 10328 | if (IS_ERR(ret)) { |
541c3bad | 10329 | tname = btf_name_by_offset(btf, t->name_off); |
4976b718 HL |
10330 | verbose(env, "ldimm64 unable to resolve the size of type '%s': %ld\n", |
10331 | tname, PTR_ERR(ret)); | |
541c3bad AN |
10332 | err = -EINVAL; |
10333 | goto err_put; | |
4976b718 HL |
10334 | } |
10335 | aux->btf_var.reg_type = PTR_TO_MEM; | |
10336 | aux->btf_var.mem_size = tsize; | |
10337 | } else { | |
10338 | aux->btf_var.reg_type = PTR_TO_BTF_ID; | |
541c3bad | 10339 | aux->btf_var.btf = btf; |
4976b718 HL |
10340 | aux->btf_var.btf_id = type; |
10341 | } | |
541c3bad AN |
10342 | |
10343 | /* check whether we recorded this BTF (and maybe module) already */ | |
10344 | for (i = 0; i < env->used_btf_cnt; i++) { | |
10345 | if (env->used_btfs[i].btf == btf) { | |
10346 | btf_put(btf); | |
10347 | return 0; | |
10348 | } | |
10349 | } | |
10350 | ||
10351 | if (env->used_btf_cnt >= MAX_USED_BTFS) { | |
10352 | err = -E2BIG; | |
10353 | goto err_put; | |
10354 | } | |
10355 | ||
10356 | btf_mod = &env->used_btfs[env->used_btf_cnt]; | |
10357 | btf_mod->btf = btf; | |
10358 | btf_mod->module = NULL; | |
10359 | ||
10360 | /* if we reference variables from kernel module, bump its refcount */ | |
10361 | if (btf_is_module(btf)) { | |
10362 | btf_mod->module = btf_try_get_module(btf); | |
10363 | if (!btf_mod->module) { | |
10364 | err = -ENXIO; | |
10365 | goto err_put; | |
10366 | } | |
10367 | } | |
10368 | ||
10369 | env->used_btf_cnt++; | |
10370 | ||
4976b718 | 10371 | return 0; |
541c3bad AN |
10372 | err_put: |
10373 | btf_put(btf); | |
10374 | return err; | |
4976b718 HL |
10375 | } |
10376 | ||
56f668df MKL |
10377 | static int check_map_prealloc(struct bpf_map *map) |
10378 | { | |
10379 | return (map->map_type != BPF_MAP_TYPE_HASH && | |
bcc6b1b7 MKL |
10380 | map->map_type != BPF_MAP_TYPE_PERCPU_HASH && |
10381 | map->map_type != BPF_MAP_TYPE_HASH_OF_MAPS) || | |
56f668df MKL |
10382 | !(map->map_flags & BPF_F_NO_PREALLOC); |
10383 | } | |
10384 | ||
d83525ca AS |
10385 | static bool is_tracing_prog_type(enum bpf_prog_type type) |
10386 | { | |
10387 | switch (type) { | |
10388 | case BPF_PROG_TYPE_KPROBE: | |
10389 | case BPF_PROG_TYPE_TRACEPOINT: | |
10390 | case BPF_PROG_TYPE_PERF_EVENT: | |
10391 | case BPF_PROG_TYPE_RAW_TRACEPOINT: | |
10392 | return true; | |
10393 | default: | |
10394 | return false; | |
10395 | } | |
10396 | } | |
10397 | ||
94dacdbd TG |
10398 | static bool is_preallocated_map(struct bpf_map *map) |
10399 | { | |
10400 | if (!check_map_prealloc(map)) | |
10401 | return false; | |
10402 | if (map->inner_map_meta && !check_map_prealloc(map->inner_map_meta)) | |
10403 | return false; | |
10404 | return true; | |
10405 | } | |
10406 | ||
61bd5218 JK |
10407 | static int check_map_prog_compatibility(struct bpf_verifier_env *env, |
10408 | struct bpf_map *map, | |
fdc15d38 AS |
10409 | struct bpf_prog *prog) |
10410 | ||
10411 | { | |
7e40781c | 10412 | enum bpf_prog_type prog_type = resolve_prog_type(prog); |
94dacdbd TG |
10413 | /* |
10414 | * Validate that trace type programs use preallocated hash maps. | |
10415 | * | |
10416 | * For programs attached to PERF events this is mandatory as the | |
10417 | * perf NMI can hit any arbitrary code sequence. | |
10418 | * | |
10419 | * All other trace types using preallocated hash maps are unsafe as | |
10420 | * well because tracepoint or kprobes can be inside locked regions | |
10421 | * of the memory allocator or at a place where a recursion into the | |
10422 | * memory allocator would see inconsistent state. | |
10423 | * | |
2ed905c5 TG |
10424 | * On RT enabled kernels run-time allocation of all trace type |
10425 | * programs is strictly prohibited due to lock type constraints. On | |
10426 | * !RT kernels it is allowed for backwards compatibility reasons for | |
10427 | * now, but warnings are emitted so developers are made aware of | |
10428 | * the unsafety and can fix their programs before this is enforced. | |
56f668df | 10429 | */ |
7e40781c UP |
10430 | if (is_tracing_prog_type(prog_type) && !is_preallocated_map(map)) { |
10431 | if (prog_type == BPF_PROG_TYPE_PERF_EVENT) { | |
61bd5218 | 10432 | verbose(env, "perf_event programs can only use preallocated hash map\n"); |
56f668df MKL |
10433 | return -EINVAL; |
10434 | } | |
2ed905c5 TG |
10435 | if (IS_ENABLED(CONFIG_PREEMPT_RT)) { |
10436 | verbose(env, "trace type programs can only use preallocated hash map\n"); | |
10437 | return -EINVAL; | |
10438 | } | |
94dacdbd TG |
10439 | WARN_ONCE(1, "trace type BPF program uses run-time allocation\n"); |
10440 | verbose(env, "trace type programs with run-time allocated hash maps are unsafe. Switch to preallocated hash maps.\n"); | |
fdc15d38 | 10441 | } |
a3884572 | 10442 | |
9e7a4d98 KS |
10443 | if (map_value_has_spin_lock(map)) { |
10444 | if (prog_type == BPF_PROG_TYPE_SOCKET_FILTER) { | |
10445 | verbose(env, "socket filter progs cannot use bpf_spin_lock yet\n"); | |
10446 | return -EINVAL; | |
10447 | } | |
10448 | ||
10449 | if (is_tracing_prog_type(prog_type)) { | |
10450 | verbose(env, "tracing progs cannot use bpf_spin_lock yet\n"); | |
10451 | return -EINVAL; | |
10452 | } | |
10453 | ||
10454 | if (prog->aux->sleepable) { | |
10455 | verbose(env, "sleepable progs cannot use bpf_spin_lock yet\n"); | |
10456 | return -EINVAL; | |
10457 | } | |
d83525ca AS |
10458 | } |
10459 | ||
a3884572 | 10460 | if ((bpf_prog_is_dev_bound(prog->aux) || bpf_map_is_dev_bound(map)) && |
09728266 | 10461 | !bpf_offload_prog_map_match(prog, map)) { |
a3884572 JK |
10462 | verbose(env, "offload device mismatch between prog and map\n"); |
10463 | return -EINVAL; | |
10464 | } | |
10465 | ||
85d33df3 MKL |
10466 | if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) { |
10467 | verbose(env, "bpf_struct_ops map cannot be used in prog\n"); | |
10468 | return -EINVAL; | |
10469 | } | |
10470 | ||
1e6c62a8 AS |
10471 | if (prog->aux->sleepable) |
10472 | switch (map->map_type) { | |
10473 | case BPF_MAP_TYPE_HASH: | |
10474 | case BPF_MAP_TYPE_LRU_HASH: | |
10475 | case BPF_MAP_TYPE_ARRAY: | |
638e4b82 AS |
10476 | case BPF_MAP_TYPE_PERCPU_HASH: |
10477 | case BPF_MAP_TYPE_PERCPU_ARRAY: | |
10478 | case BPF_MAP_TYPE_LRU_PERCPU_HASH: | |
10479 | case BPF_MAP_TYPE_ARRAY_OF_MAPS: | |
10480 | case BPF_MAP_TYPE_HASH_OF_MAPS: | |
1e6c62a8 AS |
10481 | if (!is_preallocated_map(map)) { |
10482 | verbose(env, | |
638e4b82 | 10483 | "Sleepable programs can only use preallocated maps\n"); |
1e6c62a8 AS |
10484 | return -EINVAL; |
10485 | } | |
10486 | break; | |
ba90c2cc KS |
10487 | case BPF_MAP_TYPE_RINGBUF: |
10488 | break; | |
1e6c62a8 AS |
10489 | default: |
10490 | verbose(env, | |
ba90c2cc | 10491 | "Sleepable programs can only use array, hash, and ringbuf maps\n"); |
1e6c62a8 AS |
10492 | return -EINVAL; |
10493 | } | |
10494 | ||
fdc15d38 AS |
10495 | return 0; |
10496 | } | |
10497 | ||
b741f163 RG |
10498 | static bool bpf_map_is_cgroup_storage(struct bpf_map *map) |
10499 | { | |
10500 | return (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE || | |
10501 | map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE); | |
10502 | } | |
10503 | ||
4976b718 HL |
10504 | /* find and rewrite pseudo imm in ld_imm64 instructions: |
10505 | * | |
10506 | * 1. if it accesses map FD, replace it with actual map pointer. | |
10507 | * 2. if it accesses btf_id of a VAR, replace it with pointer to the var. | |
10508 | * | |
10509 | * NOTE: btf_vmlinux is required for converting pseudo btf_id. | |
0246e64d | 10510 | */ |
4976b718 | 10511 | static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env) |
0246e64d AS |
10512 | { |
10513 | struct bpf_insn *insn = env->prog->insnsi; | |
10514 | int insn_cnt = env->prog->len; | |
fdc15d38 | 10515 | int i, j, err; |
0246e64d | 10516 | |
f1f7714e | 10517 | err = bpf_prog_calc_tag(env->prog); |
aafe6ae9 DB |
10518 | if (err) |
10519 | return err; | |
10520 | ||
0246e64d | 10521 | for (i = 0; i < insn_cnt; i++, insn++) { |
9bac3d6d | 10522 | if (BPF_CLASS(insn->code) == BPF_LDX && |
d691f9e8 | 10523 | (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0)) { |
61bd5218 | 10524 | verbose(env, "BPF_LDX uses reserved fields\n"); |
d691f9e8 AS |
10525 | return -EINVAL; |
10526 | } | |
10527 | ||
0246e64d | 10528 | if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) { |
d8eca5bb | 10529 | struct bpf_insn_aux_data *aux; |
0246e64d AS |
10530 | struct bpf_map *map; |
10531 | struct fd f; | |
d8eca5bb | 10532 | u64 addr; |
0246e64d AS |
10533 | |
10534 | if (i == insn_cnt - 1 || insn[1].code != 0 || | |
10535 | insn[1].dst_reg != 0 || insn[1].src_reg != 0 || | |
10536 | insn[1].off != 0) { | |
61bd5218 | 10537 | verbose(env, "invalid bpf_ld_imm64 insn\n"); |
0246e64d AS |
10538 | return -EINVAL; |
10539 | } | |
10540 | ||
d8eca5bb | 10541 | if (insn[0].src_reg == 0) |
0246e64d AS |
10542 | /* valid generic load 64-bit imm */ |
10543 | goto next_insn; | |
10544 | ||
4976b718 HL |
10545 | if (insn[0].src_reg == BPF_PSEUDO_BTF_ID) { |
10546 | aux = &env->insn_aux_data[i]; | |
10547 | err = check_pseudo_btf_id(env, insn, aux); | |
10548 | if (err) | |
10549 | return err; | |
10550 | goto next_insn; | |
10551 | } | |
10552 | ||
d8eca5bb DB |
10553 | /* In final convert_pseudo_ld_imm64() step, this is |
10554 | * converted into regular 64-bit imm load insn. | |
10555 | */ | |
10556 | if ((insn[0].src_reg != BPF_PSEUDO_MAP_FD && | |
10557 | insn[0].src_reg != BPF_PSEUDO_MAP_VALUE) || | |
10558 | (insn[0].src_reg == BPF_PSEUDO_MAP_FD && | |
10559 | insn[1].imm != 0)) { | |
10560 | verbose(env, | |
10561 | "unrecognized bpf_ld_imm64 insn\n"); | |
0246e64d AS |
10562 | return -EINVAL; |
10563 | } | |
10564 | ||
20182390 | 10565 | f = fdget(insn[0].imm); |
c2101297 | 10566 | map = __bpf_map_get(f); |
0246e64d | 10567 | if (IS_ERR(map)) { |
61bd5218 | 10568 | verbose(env, "fd %d is not pointing to valid bpf_map\n", |
20182390 | 10569 | insn[0].imm); |
0246e64d AS |
10570 | return PTR_ERR(map); |
10571 | } | |
10572 | ||
61bd5218 | 10573 | err = check_map_prog_compatibility(env, map, env->prog); |
fdc15d38 AS |
10574 | if (err) { |
10575 | fdput(f); | |
10576 | return err; | |
10577 | } | |
10578 | ||
d8eca5bb DB |
10579 | aux = &env->insn_aux_data[i]; |
10580 | if (insn->src_reg == BPF_PSEUDO_MAP_FD) { | |
10581 | addr = (unsigned long)map; | |
10582 | } else { | |
10583 | u32 off = insn[1].imm; | |
10584 | ||
10585 | if (off >= BPF_MAX_VAR_OFF) { | |
10586 | verbose(env, "direct value offset of %u is not allowed\n", off); | |
10587 | fdput(f); | |
10588 | return -EINVAL; | |
10589 | } | |
10590 | ||
10591 | if (!map->ops->map_direct_value_addr) { | |
10592 | verbose(env, "no direct value access support for this map type\n"); | |
10593 | fdput(f); | |
10594 | return -EINVAL; | |
10595 | } | |
10596 | ||
10597 | err = map->ops->map_direct_value_addr(map, &addr, off); | |
10598 | if (err) { | |
10599 | verbose(env, "invalid access to map value pointer, value_size=%u off=%u\n", | |
10600 | map->value_size, off); | |
10601 | fdput(f); | |
10602 | return err; | |
10603 | } | |
10604 | ||
10605 | aux->map_off = off; | |
10606 | addr += off; | |
10607 | } | |
10608 | ||
10609 | insn[0].imm = (u32)addr; | |
10610 | insn[1].imm = addr >> 32; | |
0246e64d AS |
10611 | |
10612 | /* check whether we recorded this map already */ | |
d8eca5bb | 10613 | for (j = 0; j < env->used_map_cnt; j++) { |
0246e64d | 10614 | if (env->used_maps[j] == map) { |
d8eca5bb | 10615 | aux->map_index = j; |
0246e64d AS |
10616 | fdput(f); |
10617 | goto next_insn; | |
10618 | } | |
d8eca5bb | 10619 | } |
0246e64d AS |
10620 | |
10621 | if (env->used_map_cnt >= MAX_USED_MAPS) { | |
10622 | fdput(f); | |
10623 | return -E2BIG; | |
10624 | } | |
10625 | ||
0246e64d AS |
10626 | /* hold the map. If the program is rejected by verifier, |
10627 | * the map will be released by release_maps() or it | |
10628 | * will be used by the valid program until it's unloaded | |
ab7f5bf0 | 10629 | * and all maps are released in free_used_maps() |
0246e64d | 10630 | */ |
1e0bd5a0 | 10631 | bpf_map_inc(map); |
d8eca5bb DB |
10632 | |
10633 | aux->map_index = env->used_map_cnt; | |
92117d84 AS |
10634 | env->used_maps[env->used_map_cnt++] = map; |
10635 | ||
b741f163 | 10636 | if (bpf_map_is_cgroup_storage(map) && |
e4730423 | 10637 | bpf_cgroup_storage_assign(env->prog->aux, map)) { |
b741f163 | 10638 | verbose(env, "only one cgroup storage of each type is allowed\n"); |
de9cbbaa RG |
10639 | fdput(f); |
10640 | return -EBUSY; | |
10641 | } | |
10642 | ||
0246e64d AS |
10643 | fdput(f); |
10644 | next_insn: | |
10645 | insn++; | |
10646 | i++; | |
5e581dad DB |
10647 | continue; |
10648 | } | |
10649 | ||
10650 | /* Basic sanity check before we invest more work here. */ | |
10651 | if (!bpf_opcode_in_insntable(insn->code)) { | |
10652 | verbose(env, "unknown opcode %02x\n", insn->code); | |
10653 | return -EINVAL; | |
0246e64d AS |
10654 | } |
10655 | } | |
10656 | ||
10657 | /* now all pseudo BPF_LD_IMM64 instructions load valid | |
10658 | * 'struct bpf_map *' into a register instead of user map_fd. | |
10659 | * These pointers will be used later by verifier to validate map access. | |
10660 | */ | |
10661 | return 0; | |
10662 | } | |
10663 | ||
10664 | /* drop refcnt of maps used by the rejected program */ | |
58e2af8b | 10665 | static void release_maps(struct bpf_verifier_env *env) |
0246e64d | 10666 | { |
a2ea0746 DB |
10667 | __bpf_free_used_maps(env->prog->aux, env->used_maps, |
10668 | env->used_map_cnt); | |
0246e64d AS |
10669 | } |
10670 | ||
541c3bad AN |
10671 | /* drop refcnt of maps used by the rejected program */ |
10672 | static void release_btfs(struct bpf_verifier_env *env) | |
10673 | { | |
10674 | __bpf_free_used_btfs(env->prog->aux, env->used_btfs, | |
10675 | env->used_btf_cnt); | |
10676 | } | |
10677 | ||
0246e64d | 10678 | /* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */ |
58e2af8b | 10679 | static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env) |
0246e64d AS |
10680 | { |
10681 | struct bpf_insn *insn = env->prog->insnsi; | |
10682 | int insn_cnt = env->prog->len; | |
10683 | int i; | |
10684 | ||
10685 | for (i = 0; i < insn_cnt; i++, insn++) | |
10686 | if (insn->code == (BPF_LD | BPF_IMM | BPF_DW)) | |
10687 | insn->src_reg = 0; | |
10688 | } | |
10689 | ||
8041902d AS |
10690 | /* single env->prog->insni[off] instruction was replaced with the range |
10691 | * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying | |
10692 | * [0, off) and [off, end) to new locations, so the patched range stays zero | |
10693 | */ | |
b325fbca JW |
10694 | static int adjust_insn_aux_data(struct bpf_verifier_env *env, |
10695 | struct bpf_prog *new_prog, u32 off, u32 cnt) | |
8041902d AS |
10696 | { |
10697 | struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data; | |
b325fbca JW |
10698 | struct bpf_insn *insn = new_prog->insnsi; |
10699 | u32 prog_len; | |
c131187d | 10700 | int i; |
8041902d | 10701 | |
b325fbca JW |
10702 | /* aux info at OFF always needs adjustment, no matter fast path |
10703 | * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the | |
10704 | * original insn at old prog. | |
10705 | */ | |
10706 | old_data[off].zext_dst = insn_has_def32(env, insn + off + cnt - 1); | |
10707 | ||
8041902d AS |
10708 | if (cnt == 1) |
10709 | return 0; | |
b325fbca | 10710 | prog_len = new_prog->len; |
fad953ce KC |
10711 | new_data = vzalloc(array_size(prog_len, |
10712 | sizeof(struct bpf_insn_aux_data))); | |
8041902d AS |
10713 | if (!new_data) |
10714 | return -ENOMEM; | |
10715 | memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off); | |
10716 | memcpy(new_data + off + cnt - 1, old_data + off, | |
10717 | sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1)); | |
b325fbca | 10718 | for (i = off; i < off + cnt - 1; i++) { |
51c39bb1 | 10719 | new_data[i].seen = env->pass_cnt; |
b325fbca JW |
10720 | new_data[i].zext_dst = insn_has_def32(env, insn + i); |
10721 | } | |
8041902d AS |
10722 | env->insn_aux_data = new_data; |
10723 | vfree(old_data); | |
10724 | return 0; | |
10725 | } | |
10726 | ||
cc8b0b92 AS |
10727 | static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len) |
10728 | { | |
10729 | int i; | |
10730 | ||
10731 | if (len == 1) | |
10732 | return; | |
4cb3d99c JW |
10733 | /* NOTE: fake 'exit' subprog should be updated as well. */ |
10734 | for (i = 0; i <= env->subprog_cnt; i++) { | |
afd59424 | 10735 | if (env->subprog_info[i].start <= off) |
cc8b0b92 | 10736 | continue; |
9c8105bd | 10737 | env->subprog_info[i].start += len - 1; |
cc8b0b92 AS |
10738 | } |
10739 | } | |
10740 | ||
a748c697 MF |
10741 | static void adjust_poke_descs(struct bpf_prog *prog, u32 len) |
10742 | { | |
10743 | struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; | |
10744 | int i, sz = prog->aux->size_poke_tab; | |
10745 | struct bpf_jit_poke_descriptor *desc; | |
10746 | ||
10747 | for (i = 0; i < sz; i++) { | |
10748 | desc = &tab[i]; | |
10749 | desc->insn_idx += len - 1; | |
10750 | } | |
10751 | } | |
10752 | ||
8041902d AS |
10753 | static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off, |
10754 | const struct bpf_insn *patch, u32 len) | |
10755 | { | |
10756 | struct bpf_prog *new_prog; | |
10757 | ||
10758 | new_prog = bpf_patch_insn_single(env->prog, off, patch, len); | |
4f73379e AS |
10759 | if (IS_ERR(new_prog)) { |
10760 | if (PTR_ERR(new_prog) == -ERANGE) | |
10761 | verbose(env, | |
10762 | "insn %d cannot be patched due to 16-bit range\n", | |
10763 | env->insn_aux_data[off].orig_idx); | |
8041902d | 10764 | return NULL; |
4f73379e | 10765 | } |
b325fbca | 10766 | if (adjust_insn_aux_data(env, new_prog, off, len)) |
8041902d | 10767 | return NULL; |
cc8b0b92 | 10768 | adjust_subprog_starts(env, off, len); |
a748c697 | 10769 | adjust_poke_descs(new_prog, len); |
8041902d AS |
10770 | return new_prog; |
10771 | } | |
10772 | ||
52875a04 JK |
10773 | static int adjust_subprog_starts_after_remove(struct bpf_verifier_env *env, |
10774 | u32 off, u32 cnt) | |
10775 | { | |
10776 | int i, j; | |
10777 | ||
10778 | /* find first prog starting at or after off (first to remove) */ | |
10779 | for (i = 0; i < env->subprog_cnt; i++) | |
10780 | if (env->subprog_info[i].start >= off) | |
10781 | break; | |
10782 | /* find first prog starting at or after off + cnt (first to stay) */ | |
10783 | for (j = i; j < env->subprog_cnt; j++) | |
10784 | if (env->subprog_info[j].start >= off + cnt) | |
10785 | break; | |
10786 | /* if j doesn't start exactly at off + cnt, we are just removing | |
10787 | * the front of previous prog | |
10788 | */ | |
10789 | if (env->subprog_info[j].start != off + cnt) | |
10790 | j--; | |
10791 | ||
10792 | if (j > i) { | |
10793 | struct bpf_prog_aux *aux = env->prog->aux; | |
10794 | int move; | |
10795 | ||
10796 | /* move fake 'exit' subprog as well */ | |
10797 | move = env->subprog_cnt + 1 - j; | |
10798 | ||
10799 | memmove(env->subprog_info + i, | |
10800 | env->subprog_info + j, | |
10801 | sizeof(*env->subprog_info) * move); | |
10802 | env->subprog_cnt -= j - i; | |
10803 | ||
10804 | /* remove func_info */ | |
10805 | if (aux->func_info) { | |
10806 | move = aux->func_info_cnt - j; | |
10807 | ||
10808 | memmove(aux->func_info + i, | |
10809 | aux->func_info + j, | |
10810 | sizeof(*aux->func_info) * move); | |
10811 | aux->func_info_cnt -= j - i; | |
10812 | /* func_info->insn_off is set after all code rewrites, | |
10813 | * in adjust_btf_func() - no need to adjust | |
10814 | */ | |
10815 | } | |
10816 | } else { | |
10817 | /* convert i from "first prog to remove" to "first to adjust" */ | |
10818 | if (env->subprog_info[i].start == off) | |
10819 | i++; | |
10820 | } | |
10821 | ||
10822 | /* update fake 'exit' subprog as well */ | |
10823 | for (; i <= env->subprog_cnt; i++) | |
10824 | env->subprog_info[i].start -= cnt; | |
10825 | ||
10826 | return 0; | |
10827 | } | |
10828 | ||
10829 | static int bpf_adj_linfo_after_remove(struct bpf_verifier_env *env, u32 off, | |
10830 | u32 cnt) | |
10831 | { | |
10832 | struct bpf_prog *prog = env->prog; | |
10833 | u32 i, l_off, l_cnt, nr_linfo; | |
10834 | struct bpf_line_info *linfo; | |
10835 | ||
10836 | nr_linfo = prog->aux->nr_linfo; | |
10837 | if (!nr_linfo) | |
10838 | return 0; | |
10839 | ||
10840 | linfo = prog->aux->linfo; | |
10841 | ||
10842 | /* find first line info to remove, count lines to be removed */ | |
10843 | for (i = 0; i < nr_linfo; i++) | |
10844 | if (linfo[i].insn_off >= off) | |
10845 | break; | |
10846 | ||
10847 | l_off = i; | |
10848 | l_cnt = 0; | |
10849 | for (; i < nr_linfo; i++) | |
10850 | if (linfo[i].insn_off < off + cnt) | |
10851 | l_cnt++; | |
10852 | else | |
10853 | break; | |
10854 | ||
10855 | /* First live insn doesn't match first live linfo, it needs to "inherit" | |
10856 | * last removed linfo. prog is already modified, so prog->len == off | |
10857 | * means no live instructions after (tail of the program was removed). | |
10858 | */ | |
10859 | if (prog->len != off && l_cnt && | |
10860 | (i == nr_linfo || linfo[i].insn_off != off + cnt)) { | |
10861 | l_cnt--; | |
10862 | linfo[--i].insn_off = off + cnt; | |
10863 | } | |
10864 | ||
10865 | /* remove the line info which refer to the removed instructions */ | |
10866 | if (l_cnt) { | |
10867 | memmove(linfo + l_off, linfo + i, | |
10868 | sizeof(*linfo) * (nr_linfo - i)); | |
10869 | ||
10870 | prog->aux->nr_linfo -= l_cnt; | |
10871 | nr_linfo = prog->aux->nr_linfo; | |
10872 | } | |
10873 | ||
10874 | /* pull all linfo[i].insn_off >= off + cnt in by cnt */ | |
10875 | for (i = l_off; i < nr_linfo; i++) | |
10876 | linfo[i].insn_off -= cnt; | |
10877 | ||
10878 | /* fix up all subprogs (incl. 'exit') which start >= off */ | |
10879 | for (i = 0; i <= env->subprog_cnt; i++) | |
10880 | if (env->subprog_info[i].linfo_idx > l_off) { | |
10881 | /* program may have started in the removed region but | |
10882 | * may not be fully removed | |
10883 | */ | |
10884 | if (env->subprog_info[i].linfo_idx >= l_off + l_cnt) | |
10885 | env->subprog_info[i].linfo_idx -= l_cnt; | |
10886 | else | |
10887 | env->subprog_info[i].linfo_idx = l_off; | |
10888 | } | |
10889 | ||
10890 | return 0; | |
10891 | } | |
10892 | ||
10893 | static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt) | |
10894 | { | |
10895 | struct bpf_insn_aux_data *aux_data = env->insn_aux_data; | |
10896 | unsigned int orig_prog_len = env->prog->len; | |
10897 | int err; | |
10898 | ||
08ca90af JK |
10899 | if (bpf_prog_is_dev_bound(env->prog->aux)) |
10900 | bpf_prog_offload_remove_insns(env, off, cnt); | |
10901 | ||
52875a04 JK |
10902 | err = bpf_remove_insns(env->prog, off, cnt); |
10903 | if (err) | |
10904 | return err; | |
10905 | ||
10906 | err = adjust_subprog_starts_after_remove(env, off, cnt); | |
10907 | if (err) | |
10908 | return err; | |
10909 | ||
10910 | err = bpf_adj_linfo_after_remove(env, off, cnt); | |
10911 | if (err) | |
10912 | return err; | |
10913 | ||
10914 | memmove(aux_data + off, aux_data + off + cnt, | |
10915 | sizeof(*aux_data) * (orig_prog_len - off - cnt)); | |
10916 | ||
10917 | return 0; | |
10918 | } | |
10919 | ||
2a5418a1 DB |
10920 | /* The verifier does more data flow analysis than llvm and will not |
10921 | * explore branches that are dead at run time. Malicious programs can | |
10922 | * have dead code too. Therefore replace all dead at-run-time code | |
10923 | * with 'ja -1'. | |
10924 | * | |
10925 | * Just nops are not optimal, e.g. if they would sit at the end of the | |
10926 | * program and through another bug we would manage to jump there, then | |
10927 | * we'd execute beyond program memory otherwise. Returning exception | |
10928 | * code also wouldn't work since we can have subprogs where the dead | |
10929 | * code could be located. | |
c131187d AS |
10930 | */ |
10931 | static void sanitize_dead_code(struct bpf_verifier_env *env) | |
10932 | { | |
10933 | struct bpf_insn_aux_data *aux_data = env->insn_aux_data; | |
2a5418a1 | 10934 | struct bpf_insn trap = BPF_JMP_IMM(BPF_JA, 0, 0, -1); |
c131187d AS |
10935 | struct bpf_insn *insn = env->prog->insnsi; |
10936 | const int insn_cnt = env->prog->len; | |
10937 | int i; | |
10938 | ||
10939 | for (i = 0; i < insn_cnt; i++) { | |
10940 | if (aux_data[i].seen) | |
10941 | continue; | |
2a5418a1 | 10942 | memcpy(insn + i, &trap, sizeof(trap)); |
c131187d AS |
10943 | } |
10944 | } | |
10945 | ||
e2ae4ca2 JK |
10946 | static bool insn_is_cond_jump(u8 code) |
10947 | { | |
10948 | u8 op; | |
10949 | ||
092ed096 JW |
10950 | if (BPF_CLASS(code) == BPF_JMP32) |
10951 | return true; | |
10952 | ||
e2ae4ca2 JK |
10953 | if (BPF_CLASS(code) != BPF_JMP) |
10954 | return false; | |
10955 | ||
10956 | op = BPF_OP(code); | |
10957 | return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL; | |
10958 | } | |
10959 | ||
10960 | static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env) | |
10961 | { | |
10962 | struct bpf_insn_aux_data *aux_data = env->insn_aux_data; | |
10963 | struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0); | |
10964 | struct bpf_insn *insn = env->prog->insnsi; | |
10965 | const int insn_cnt = env->prog->len; | |
10966 | int i; | |
10967 | ||
10968 | for (i = 0; i < insn_cnt; i++, insn++) { | |
10969 | if (!insn_is_cond_jump(insn->code)) | |
10970 | continue; | |
10971 | ||
10972 | if (!aux_data[i + 1].seen) | |
10973 | ja.off = insn->off; | |
10974 | else if (!aux_data[i + 1 + insn->off].seen) | |
10975 | ja.off = 0; | |
10976 | else | |
10977 | continue; | |
10978 | ||
08ca90af JK |
10979 | if (bpf_prog_is_dev_bound(env->prog->aux)) |
10980 | bpf_prog_offload_replace_insn(env, i, &ja); | |
10981 | ||
e2ae4ca2 JK |
10982 | memcpy(insn, &ja, sizeof(ja)); |
10983 | } | |
10984 | } | |
10985 | ||
52875a04 JK |
10986 | static int opt_remove_dead_code(struct bpf_verifier_env *env) |
10987 | { | |
10988 | struct bpf_insn_aux_data *aux_data = env->insn_aux_data; | |
10989 | int insn_cnt = env->prog->len; | |
10990 | int i, err; | |
10991 | ||
10992 | for (i = 0; i < insn_cnt; i++) { | |
10993 | int j; | |
10994 | ||
10995 | j = 0; | |
10996 | while (i + j < insn_cnt && !aux_data[i + j].seen) | |
10997 | j++; | |
10998 | if (!j) | |
10999 | continue; | |
11000 | ||
11001 | err = verifier_remove_insns(env, i, j); | |
11002 | if (err) | |
11003 | return err; | |
11004 | insn_cnt = env->prog->len; | |
11005 | } | |
11006 | ||
11007 | return 0; | |
11008 | } | |
11009 | ||
a1b14abc JK |
11010 | static int opt_remove_nops(struct bpf_verifier_env *env) |
11011 | { | |
11012 | const struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0); | |
11013 | struct bpf_insn *insn = env->prog->insnsi; | |
11014 | int insn_cnt = env->prog->len; | |
11015 | int i, err; | |
11016 | ||
11017 | for (i = 0; i < insn_cnt; i++) { | |
11018 | if (memcmp(&insn[i], &ja, sizeof(ja))) | |
11019 | continue; | |
11020 | ||
11021 | err = verifier_remove_insns(env, i, 1); | |
11022 | if (err) | |
11023 | return err; | |
11024 | insn_cnt--; | |
11025 | i--; | |
11026 | } | |
11027 | ||
11028 | return 0; | |
11029 | } | |
11030 | ||
d6c2308c JW |
11031 | static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env, |
11032 | const union bpf_attr *attr) | |
a4b1d3c1 | 11033 | { |
d6c2308c | 11034 | struct bpf_insn *patch, zext_patch[2], rnd_hi32_patch[4]; |
a4b1d3c1 | 11035 | struct bpf_insn_aux_data *aux = env->insn_aux_data; |
d6c2308c | 11036 | int i, patch_len, delta = 0, len = env->prog->len; |
a4b1d3c1 | 11037 | struct bpf_insn *insns = env->prog->insnsi; |
a4b1d3c1 | 11038 | struct bpf_prog *new_prog; |
d6c2308c | 11039 | bool rnd_hi32; |
a4b1d3c1 | 11040 | |
d6c2308c | 11041 | rnd_hi32 = attr->prog_flags & BPF_F_TEST_RND_HI32; |
a4b1d3c1 | 11042 | zext_patch[1] = BPF_ZEXT_REG(0); |
d6c2308c JW |
11043 | rnd_hi32_patch[1] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, 0); |
11044 | rnd_hi32_patch[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); | |
11045 | rnd_hi32_patch[3] = BPF_ALU64_REG(BPF_OR, 0, BPF_REG_AX); | |
a4b1d3c1 JW |
11046 | for (i = 0; i < len; i++) { |
11047 | int adj_idx = i + delta; | |
11048 | struct bpf_insn insn; | |
83a28819 | 11049 | int load_reg; |
a4b1d3c1 | 11050 | |
d6c2308c | 11051 | insn = insns[adj_idx]; |
83a28819 | 11052 | load_reg = insn_def_regno(&insn); |
d6c2308c JW |
11053 | if (!aux[adj_idx].zext_dst) { |
11054 | u8 code, class; | |
11055 | u32 imm_rnd; | |
11056 | ||
11057 | if (!rnd_hi32) | |
11058 | continue; | |
11059 | ||
11060 | code = insn.code; | |
11061 | class = BPF_CLASS(code); | |
83a28819 | 11062 | if (load_reg == -1) |
d6c2308c JW |
11063 | continue; |
11064 | ||
11065 | /* NOTE: arg "reg" (the fourth one) is only used for | |
83a28819 IL |
11066 | * BPF_STX + SRC_OP, so it is safe to pass NULL |
11067 | * here. | |
d6c2308c | 11068 | */ |
83a28819 | 11069 | if (is_reg64(env, &insn, load_reg, NULL, DST_OP)) { |
d6c2308c JW |
11070 | if (class == BPF_LD && |
11071 | BPF_MODE(code) == BPF_IMM) | |
11072 | i++; | |
11073 | continue; | |
11074 | } | |
11075 | ||
11076 | /* ctx load could be transformed into wider load. */ | |
11077 | if (class == BPF_LDX && | |
11078 | aux[adj_idx].ptr_type == PTR_TO_CTX) | |
11079 | continue; | |
11080 | ||
11081 | imm_rnd = get_random_int(); | |
11082 | rnd_hi32_patch[0] = insn; | |
11083 | rnd_hi32_patch[1].imm = imm_rnd; | |
83a28819 | 11084 | rnd_hi32_patch[3].dst_reg = load_reg; |
d6c2308c JW |
11085 | patch = rnd_hi32_patch; |
11086 | patch_len = 4; | |
11087 | goto apply_patch_buffer; | |
11088 | } | |
11089 | ||
39491867 BJ |
11090 | /* Add in an zero-extend instruction if a) the JIT has requested |
11091 | * it or b) it's a CMPXCHG. | |
11092 | * | |
11093 | * The latter is because: BPF_CMPXCHG always loads a value into | |
11094 | * R0, therefore always zero-extends. However some archs' | |
11095 | * equivalent instruction only does this load when the | |
11096 | * comparison is successful. This detail of CMPXCHG is | |
11097 | * orthogonal to the general zero-extension behaviour of the | |
11098 | * CPU, so it's treated independently of bpf_jit_needs_zext. | |
11099 | */ | |
11100 | if (!bpf_jit_needs_zext() && !is_cmpxchg_insn(&insn)) | |
a4b1d3c1 JW |
11101 | continue; |
11102 | ||
83a28819 IL |
11103 | if (WARN_ON(load_reg == -1)) { |
11104 | verbose(env, "verifier bug. zext_dst is set, but no reg is defined\n"); | |
11105 | return -EFAULT; | |
b2e37a71 IL |
11106 | } |
11107 | ||
a4b1d3c1 | 11108 | zext_patch[0] = insn; |
b2e37a71 IL |
11109 | zext_patch[1].dst_reg = load_reg; |
11110 | zext_patch[1].src_reg = load_reg; | |
d6c2308c JW |
11111 | patch = zext_patch; |
11112 | patch_len = 2; | |
11113 | apply_patch_buffer: | |
11114 | new_prog = bpf_patch_insn_data(env, adj_idx, patch, patch_len); | |
a4b1d3c1 JW |
11115 | if (!new_prog) |
11116 | return -ENOMEM; | |
11117 | env->prog = new_prog; | |
11118 | insns = new_prog->insnsi; | |
11119 | aux = env->insn_aux_data; | |
d6c2308c | 11120 | delta += patch_len - 1; |
a4b1d3c1 JW |
11121 | } |
11122 | ||
11123 | return 0; | |
11124 | } | |
11125 | ||
c64b7983 JS |
11126 | /* convert load instructions that access fields of a context type into a |
11127 | * sequence of instructions that access fields of the underlying structure: | |
11128 | * struct __sk_buff -> struct sk_buff | |
11129 | * struct bpf_sock_ops -> struct sock | |
9bac3d6d | 11130 | */ |
58e2af8b | 11131 | static int convert_ctx_accesses(struct bpf_verifier_env *env) |
9bac3d6d | 11132 | { |
00176a34 | 11133 | const struct bpf_verifier_ops *ops = env->ops; |
f96da094 | 11134 | int i, cnt, size, ctx_field_size, delta = 0; |
3df126f3 | 11135 | const int insn_cnt = env->prog->len; |
36bbef52 | 11136 | struct bpf_insn insn_buf[16], *insn; |
46f53a65 | 11137 | u32 target_size, size_default, off; |
9bac3d6d | 11138 | struct bpf_prog *new_prog; |
d691f9e8 | 11139 | enum bpf_access_type type; |
f96da094 | 11140 | bool is_narrower_load; |
9bac3d6d | 11141 | |
b09928b9 DB |
11142 | if (ops->gen_prologue || env->seen_direct_write) { |
11143 | if (!ops->gen_prologue) { | |
11144 | verbose(env, "bpf verifier is misconfigured\n"); | |
11145 | return -EINVAL; | |
11146 | } | |
36bbef52 DB |
11147 | cnt = ops->gen_prologue(insn_buf, env->seen_direct_write, |
11148 | env->prog); | |
11149 | if (cnt >= ARRAY_SIZE(insn_buf)) { | |
61bd5218 | 11150 | verbose(env, "bpf verifier is misconfigured\n"); |
36bbef52 DB |
11151 | return -EINVAL; |
11152 | } else if (cnt) { | |
8041902d | 11153 | new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt); |
36bbef52 DB |
11154 | if (!new_prog) |
11155 | return -ENOMEM; | |
8041902d | 11156 | |
36bbef52 | 11157 | env->prog = new_prog; |
3df126f3 | 11158 | delta += cnt - 1; |
36bbef52 DB |
11159 | } |
11160 | } | |
11161 | ||
c64b7983 | 11162 | if (bpf_prog_is_dev_bound(env->prog->aux)) |
9bac3d6d AS |
11163 | return 0; |
11164 | ||
3df126f3 | 11165 | insn = env->prog->insnsi + delta; |
36bbef52 | 11166 | |
9bac3d6d | 11167 | for (i = 0; i < insn_cnt; i++, insn++) { |
c64b7983 JS |
11168 | bpf_convert_ctx_access_t convert_ctx_access; |
11169 | ||
62c7989b DB |
11170 | if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) || |
11171 | insn->code == (BPF_LDX | BPF_MEM | BPF_H) || | |
11172 | insn->code == (BPF_LDX | BPF_MEM | BPF_W) || | |
ea2e7ce5 | 11173 | insn->code == (BPF_LDX | BPF_MEM | BPF_DW)) |
d691f9e8 | 11174 | type = BPF_READ; |
62c7989b DB |
11175 | else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) || |
11176 | insn->code == (BPF_STX | BPF_MEM | BPF_H) || | |
11177 | insn->code == (BPF_STX | BPF_MEM | BPF_W) || | |
ea2e7ce5 | 11178 | insn->code == (BPF_STX | BPF_MEM | BPF_DW)) |
d691f9e8 AS |
11179 | type = BPF_WRITE; |
11180 | else | |
9bac3d6d AS |
11181 | continue; |
11182 | ||
af86ca4e AS |
11183 | if (type == BPF_WRITE && |
11184 | env->insn_aux_data[i + delta].sanitize_stack_off) { | |
11185 | struct bpf_insn patch[] = { | |
11186 | /* Sanitize suspicious stack slot with zero. | |
11187 | * There are no memory dependencies for this store, | |
11188 | * since it's only using frame pointer and immediate | |
11189 | * constant of zero | |
11190 | */ | |
11191 | BPF_ST_MEM(BPF_DW, BPF_REG_FP, | |
11192 | env->insn_aux_data[i + delta].sanitize_stack_off, | |
11193 | 0), | |
11194 | /* the original STX instruction will immediately | |
11195 | * overwrite the same stack slot with appropriate value | |
11196 | */ | |
11197 | *insn, | |
11198 | }; | |
11199 | ||
11200 | cnt = ARRAY_SIZE(patch); | |
11201 | new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt); | |
11202 | if (!new_prog) | |
11203 | return -ENOMEM; | |
11204 | ||
11205 | delta += cnt - 1; | |
11206 | env->prog = new_prog; | |
11207 | insn = new_prog->insnsi + i + delta; | |
11208 | continue; | |
11209 | } | |
11210 | ||
c64b7983 JS |
11211 | switch (env->insn_aux_data[i + delta].ptr_type) { |
11212 | case PTR_TO_CTX: | |
11213 | if (!ops->convert_ctx_access) | |
11214 | continue; | |
11215 | convert_ctx_access = ops->convert_ctx_access; | |
11216 | break; | |
11217 | case PTR_TO_SOCKET: | |
46f8bc92 | 11218 | case PTR_TO_SOCK_COMMON: |
c64b7983 JS |
11219 | convert_ctx_access = bpf_sock_convert_ctx_access; |
11220 | break; | |
655a51e5 MKL |
11221 | case PTR_TO_TCP_SOCK: |
11222 | convert_ctx_access = bpf_tcp_sock_convert_ctx_access; | |
11223 | break; | |
fada7fdc JL |
11224 | case PTR_TO_XDP_SOCK: |
11225 | convert_ctx_access = bpf_xdp_sock_convert_ctx_access; | |
11226 | break; | |
2a02759e | 11227 | case PTR_TO_BTF_ID: |
27ae7997 MKL |
11228 | if (type == BPF_READ) { |
11229 | insn->code = BPF_LDX | BPF_PROBE_MEM | | |
11230 | BPF_SIZE((insn)->code); | |
11231 | env->prog->aux->num_exentries++; | |
7e40781c | 11232 | } else if (resolve_prog_type(env->prog) != BPF_PROG_TYPE_STRUCT_OPS) { |
2a02759e AS |
11233 | verbose(env, "Writes through BTF pointers are not allowed\n"); |
11234 | return -EINVAL; | |
11235 | } | |
2a02759e | 11236 | continue; |
c64b7983 | 11237 | default: |
9bac3d6d | 11238 | continue; |
c64b7983 | 11239 | } |
9bac3d6d | 11240 | |
31fd8581 | 11241 | ctx_field_size = env->insn_aux_data[i + delta].ctx_field_size; |
f96da094 | 11242 | size = BPF_LDST_BYTES(insn); |
31fd8581 YS |
11243 | |
11244 | /* If the read access is a narrower load of the field, | |
11245 | * convert to a 4/8-byte load, to minimum program type specific | |
11246 | * convert_ctx_access changes. If conversion is successful, | |
11247 | * we will apply proper mask to the result. | |
11248 | */ | |
f96da094 | 11249 | is_narrower_load = size < ctx_field_size; |
46f53a65 AI |
11250 | size_default = bpf_ctx_off_adjust_machine(ctx_field_size); |
11251 | off = insn->off; | |
31fd8581 | 11252 | if (is_narrower_load) { |
f96da094 DB |
11253 | u8 size_code; |
11254 | ||
11255 | if (type == BPF_WRITE) { | |
61bd5218 | 11256 | verbose(env, "bpf verifier narrow ctx access misconfigured\n"); |
f96da094 DB |
11257 | return -EINVAL; |
11258 | } | |
31fd8581 | 11259 | |
f96da094 | 11260 | size_code = BPF_H; |
31fd8581 YS |
11261 | if (ctx_field_size == 4) |
11262 | size_code = BPF_W; | |
11263 | else if (ctx_field_size == 8) | |
11264 | size_code = BPF_DW; | |
f96da094 | 11265 | |
bc23105c | 11266 | insn->off = off & ~(size_default - 1); |
31fd8581 YS |
11267 | insn->code = BPF_LDX | BPF_MEM | size_code; |
11268 | } | |
f96da094 DB |
11269 | |
11270 | target_size = 0; | |
c64b7983 JS |
11271 | cnt = convert_ctx_access(type, insn, insn_buf, env->prog, |
11272 | &target_size); | |
f96da094 DB |
11273 | if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) || |
11274 | (ctx_field_size && !target_size)) { | |
61bd5218 | 11275 | verbose(env, "bpf verifier is misconfigured\n"); |
9bac3d6d AS |
11276 | return -EINVAL; |
11277 | } | |
f96da094 DB |
11278 | |
11279 | if (is_narrower_load && size < target_size) { | |
d895a0f1 IL |
11280 | u8 shift = bpf_ctx_narrow_access_offset( |
11281 | off, size, size_default) * 8; | |
46f53a65 AI |
11282 | if (ctx_field_size <= 4) { |
11283 | if (shift) | |
11284 | insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH, | |
11285 | insn->dst_reg, | |
11286 | shift); | |
31fd8581 | 11287 | insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg, |
f96da094 | 11288 | (1 << size * 8) - 1); |
46f53a65 AI |
11289 | } else { |
11290 | if (shift) | |
11291 | insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH, | |
11292 | insn->dst_reg, | |
11293 | shift); | |
31fd8581 | 11294 | insn_buf[cnt++] = BPF_ALU64_IMM(BPF_AND, insn->dst_reg, |
e2f7fc0a | 11295 | (1ULL << size * 8) - 1); |
46f53a65 | 11296 | } |
31fd8581 | 11297 | } |
9bac3d6d | 11298 | |
8041902d | 11299 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); |
9bac3d6d AS |
11300 | if (!new_prog) |
11301 | return -ENOMEM; | |
11302 | ||
3df126f3 | 11303 | delta += cnt - 1; |
9bac3d6d AS |
11304 | |
11305 | /* keep walking new program and skip insns we just inserted */ | |
11306 | env->prog = new_prog; | |
3df126f3 | 11307 | insn = new_prog->insnsi + i + delta; |
9bac3d6d AS |
11308 | } |
11309 | ||
11310 | return 0; | |
11311 | } | |
11312 | ||
1c2a088a AS |
11313 | static int jit_subprogs(struct bpf_verifier_env *env) |
11314 | { | |
11315 | struct bpf_prog *prog = env->prog, **func, *tmp; | |
11316 | int i, j, subprog_start, subprog_end = 0, len, subprog; | |
a748c697 | 11317 | struct bpf_map *map_ptr; |
7105e828 | 11318 | struct bpf_insn *insn; |
1c2a088a | 11319 | void *old_bpf_func; |
c4c0bdc0 | 11320 | int err, num_exentries; |
1c2a088a | 11321 | |
f910cefa | 11322 | if (env->subprog_cnt <= 1) |
1c2a088a AS |
11323 | return 0; |
11324 | ||
7105e828 | 11325 | for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { |
23a2d70c | 11326 | if (!bpf_pseudo_call(insn)) |
1c2a088a | 11327 | continue; |
c7a89784 DB |
11328 | /* Upon error here we cannot fall back to interpreter but |
11329 | * need a hard reject of the program. Thus -EFAULT is | |
11330 | * propagated in any case. | |
11331 | */ | |
1c2a088a AS |
11332 | subprog = find_subprog(env, i + insn->imm + 1); |
11333 | if (subprog < 0) { | |
11334 | WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", | |
11335 | i + insn->imm + 1); | |
11336 | return -EFAULT; | |
11337 | } | |
11338 | /* temporarily remember subprog id inside insn instead of | |
11339 | * aux_data, since next loop will split up all insns into funcs | |
11340 | */ | |
f910cefa | 11341 | insn->off = subprog; |
1c2a088a AS |
11342 | /* remember original imm in case JIT fails and fallback |
11343 | * to interpreter will be needed | |
11344 | */ | |
11345 | env->insn_aux_data[i].call_imm = insn->imm; | |
11346 | /* point imm to __bpf_call_base+1 from JITs point of view */ | |
11347 | insn->imm = 1; | |
11348 | } | |
11349 | ||
c454a46b MKL |
11350 | err = bpf_prog_alloc_jited_linfo(prog); |
11351 | if (err) | |
11352 | goto out_undo_insn; | |
11353 | ||
11354 | err = -ENOMEM; | |
6396bb22 | 11355 | func = kcalloc(env->subprog_cnt, sizeof(prog), GFP_KERNEL); |
1c2a088a | 11356 | if (!func) |
c7a89784 | 11357 | goto out_undo_insn; |
1c2a088a | 11358 | |
f910cefa | 11359 | for (i = 0; i < env->subprog_cnt; i++) { |
1c2a088a | 11360 | subprog_start = subprog_end; |
4cb3d99c | 11361 | subprog_end = env->subprog_info[i + 1].start; |
1c2a088a AS |
11362 | |
11363 | len = subprog_end - subprog_start; | |
492ecee8 AS |
11364 | /* BPF_PROG_RUN doesn't call subprogs directly, |
11365 | * hence main prog stats include the runtime of subprogs. | |
11366 | * subprogs don't have IDs and not reachable via prog_get_next_id | |
700d4796 | 11367 | * func[i]->stats will never be accessed and stays NULL |
492ecee8 AS |
11368 | */ |
11369 | func[i] = bpf_prog_alloc_no_stats(bpf_prog_size(len), GFP_USER); | |
1c2a088a AS |
11370 | if (!func[i]) |
11371 | goto out_free; | |
11372 | memcpy(func[i]->insnsi, &prog->insnsi[subprog_start], | |
11373 | len * sizeof(struct bpf_insn)); | |
4f74d809 | 11374 | func[i]->type = prog->type; |
1c2a088a | 11375 | func[i]->len = len; |
4f74d809 DB |
11376 | if (bpf_prog_calc_tag(func[i])) |
11377 | goto out_free; | |
1c2a088a | 11378 | func[i]->is_func = 1; |
ba64e7d8 YS |
11379 | func[i]->aux->func_idx = i; |
11380 | /* the btf and func_info will be freed only at prog->aux */ | |
11381 | func[i]->aux->btf = prog->aux->btf; | |
11382 | func[i]->aux->func_info = prog->aux->func_info; | |
11383 | ||
a748c697 MF |
11384 | for (j = 0; j < prog->aux->size_poke_tab; j++) { |
11385 | u32 insn_idx = prog->aux->poke_tab[j].insn_idx; | |
11386 | int ret; | |
11387 | ||
11388 | if (!(insn_idx >= subprog_start && | |
11389 | insn_idx <= subprog_end)) | |
11390 | continue; | |
11391 | ||
11392 | ret = bpf_jit_add_poke_descriptor(func[i], | |
11393 | &prog->aux->poke_tab[j]); | |
11394 | if (ret < 0) { | |
11395 | verbose(env, "adding tail call poke descriptor failed\n"); | |
11396 | goto out_free; | |
11397 | } | |
11398 | ||
11399 | func[i]->insnsi[insn_idx - subprog_start].imm = ret + 1; | |
11400 | ||
11401 | map_ptr = func[i]->aux->poke_tab[ret].tail_call.map; | |
11402 | ret = map_ptr->ops->map_poke_track(map_ptr, func[i]->aux); | |
11403 | if (ret < 0) { | |
11404 | verbose(env, "tracking tail call prog failed\n"); | |
11405 | goto out_free; | |
11406 | } | |
11407 | } | |
11408 | ||
1c2a088a AS |
11409 | /* Use bpf_prog_F_tag to indicate functions in stack traces. |
11410 | * Long term would need debug info to populate names | |
11411 | */ | |
11412 | func[i]->aux->name[0] = 'F'; | |
9c8105bd | 11413 | func[i]->aux->stack_depth = env->subprog_info[i].stack_depth; |
1c2a088a | 11414 | func[i]->jit_requested = 1; |
c454a46b MKL |
11415 | func[i]->aux->linfo = prog->aux->linfo; |
11416 | func[i]->aux->nr_linfo = prog->aux->nr_linfo; | |
11417 | func[i]->aux->jited_linfo = prog->aux->jited_linfo; | |
11418 | func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx; | |
c4c0bdc0 YS |
11419 | num_exentries = 0; |
11420 | insn = func[i]->insnsi; | |
11421 | for (j = 0; j < func[i]->len; j++, insn++) { | |
11422 | if (BPF_CLASS(insn->code) == BPF_LDX && | |
11423 | BPF_MODE(insn->code) == BPF_PROBE_MEM) | |
11424 | num_exentries++; | |
11425 | } | |
11426 | func[i]->aux->num_exentries = num_exentries; | |
ebf7d1f5 | 11427 | func[i]->aux->tail_call_reachable = env->subprog_info[i].tail_call_reachable; |
1c2a088a AS |
11428 | func[i] = bpf_int_jit_compile(func[i]); |
11429 | if (!func[i]->jited) { | |
11430 | err = -ENOTSUPP; | |
11431 | goto out_free; | |
11432 | } | |
11433 | cond_resched(); | |
11434 | } | |
a748c697 MF |
11435 | |
11436 | /* Untrack main program's aux structs so that during map_poke_run() | |
11437 | * we will not stumble upon the unfilled poke descriptors; each | |
11438 | * of the main program's poke descs got distributed across subprogs | |
11439 | * and got tracked onto map, so we are sure that none of them will | |
11440 | * be missed after the operation below | |
11441 | */ | |
11442 | for (i = 0; i < prog->aux->size_poke_tab; i++) { | |
11443 | map_ptr = prog->aux->poke_tab[i].tail_call.map; | |
11444 | ||
11445 | map_ptr->ops->map_poke_untrack(map_ptr, prog->aux); | |
11446 | } | |
11447 | ||
1c2a088a AS |
11448 | /* at this point all bpf functions were successfully JITed |
11449 | * now populate all bpf_calls with correct addresses and | |
11450 | * run last pass of JIT | |
11451 | */ | |
f910cefa | 11452 | for (i = 0; i < env->subprog_cnt; i++) { |
1c2a088a AS |
11453 | insn = func[i]->insnsi; |
11454 | for (j = 0; j < func[i]->len; j++, insn++) { | |
23a2d70c | 11455 | if (!bpf_pseudo_call(insn)) |
1c2a088a AS |
11456 | continue; |
11457 | subprog = insn->off; | |
0d306c31 PB |
11458 | insn->imm = BPF_CAST_CALL(func[subprog]->bpf_func) - |
11459 | __bpf_call_base; | |
1c2a088a | 11460 | } |
2162fed4 SD |
11461 | |
11462 | /* we use the aux data to keep a list of the start addresses | |
11463 | * of the JITed images for each function in the program | |
11464 | * | |
11465 | * for some architectures, such as powerpc64, the imm field | |
11466 | * might not be large enough to hold the offset of the start | |
11467 | * address of the callee's JITed image from __bpf_call_base | |
11468 | * | |
11469 | * in such cases, we can lookup the start address of a callee | |
11470 | * by using its subprog id, available from the off field of | |
11471 | * the call instruction, as an index for this list | |
11472 | */ | |
11473 | func[i]->aux->func = func; | |
11474 | func[i]->aux->func_cnt = env->subprog_cnt; | |
1c2a088a | 11475 | } |
f910cefa | 11476 | for (i = 0; i < env->subprog_cnt; i++) { |
1c2a088a AS |
11477 | old_bpf_func = func[i]->bpf_func; |
11478 | tmp = bpf_int_jit_compile(func[i]); | |
11479 | if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) { | |
11480 | verbose(env, "JIT doesn't support bpf-to-bpf calls\n"); | |
c7a89784 | 11481 | err = -ENOTSUPP; |
1c2a088a AS |
11482 | goto out_free; |
11483 | } | |
11484 | cond_resched(); | |
11485 | } | |
11486 | ||
11487 | /* finally lock prog and jit images for all functions and | |
11488 | * populate kallsysm | |
11489 | */ | |
f910cefa | 11490 | for (i = 0; i < env->subprog_cnt; i++) { |
1c2a088a AS |
11491 | bpf_prog_lock_ro(func[i]); |
11492 | bpf_prog_kallsyms_add(func[i]); | |
11493 | } | |
7105e828 DB |
11494 | |
11495 | /* Last step: make now unused interpreter insns from main | |
11496 | * prog consistent for later dump requests, so they can | |
11497 | * later look the same as if they were interpreted only. | |
11498 | */ | |
11499 | for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { | |
23a2d70c | 11500 | if (!bpf_pseudo_call(insn)) |
7105e828 DB |
11501 | continue; |
11502 | insn->off = env->insn_aux_data[i].call_imm; | |
11503 | subprog = find_subprog(env, i + insn->off + 1); | |
dbecd738 | 11504 | insn->imm = subprog; |
7105e828 DB |
11505 | } |
11506 | ||
1c2a088a AS |
11507 | prog->jited = 1; |
11508 | prog->bpf_func = func[0]->bpf_func; | |
11509 | prog->aux->func = func; | |
f910cefa | 11510 | prog->aux->func_cnt = env->subprog_cnt; |
c454a46b | 11511 | bpf_prog_free_unused_jited_linfo(prog); |
1c2a088a AS |
11512 | return 0; |
11513 | out_free: | |
a748c697 MF |
11514 | for (i = 0; i < env->subprog_cnt; i++) { |
11515 | if (!func[i]) | |
11516 | continue; | |
11517 | ||
11518 | for (j = 0; j < func[i]->aux->size_poke_tab; j++) { | |
11519 | map_ptr = func[i]->aux->poke_tab[j].tail_call.map; | |
11520 | map_ptr->ops->map_poke_untrack(map_ptr, func[i]->aux); | |
11521 | } | |
11522 | bpf_jit_free(func[i]); | |
11523 | } | |
1c2a088a | 11524 | kfree(func); |
c7a89784 | 11525 | out_undo_insn: |
1c2a088a AS |
11526 | /* cleanup main prog to be interpreted */ |
11527 | prog->jit_requested = 0; | |
11528 | for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { | |
23a2d70c | 11529 | if (!bpf_pseudo_call(insn)) |
1c2a088a AS |
11530 | continue; |
11531 | insn->off = 0; | |
11532 | insn->imm = env->insn_aux_data[i].call_imm; | |
11533 | } | |
c454a46b | 11534 | bpf_prog_free_jited_linfo(prog); |
1c2a088a AS |
11535 | return err; |
11536 | } | |
11537 | ||
1ea47e01 AS |
11538 | static int fixup_call_args(struct bpf_verifier_env *env) |
11539 | { | |
19d28fbd | 11540 | #ifndef CONFIG_BPF_JIT_ALWAYS_ON |
1ea47e01 AS |
11541 | struct bpf_prog *prog = env->prog; |
11542 | struct bpf_insn *insn = prog->insnsi; | |
11543 | int i, depth; | |
19d28fbd | 11544 | #endif |
e4052d06 | 11545 | int err = 0; |
1ea47e01 | 11546 | |
e4052d06 QM |
11547 | if (env->prog->jit_requested && |
11548 | !bpf_prog_is_dev_bound(env->prog->aux)) { | |
19d28fbd DM |
11549 | err = jit_subprogs(env); |
11550 | if (err == 0) | |
1c2a088a | 11551 | return 0; |
c7a89784 DB |
11552 | if (err == -EFAULT) |
11553 | return err; | |
19d28fbd DM |
11554 | } |
11555 | #ifndef CONFIG_BPF_JIT_ALWAYS_ON | |
e411901c MF |
11556 | if (env->subprog_cnt > 1 && env->prog->aux->tail_call_reachable) { |
11557 | /* When JIT fails the progs with bpf2bpf calls and tail_calls | |
11558 | * have to be rejected, since interpreter doesn't support them yet. | |
11559 | */ | |
11560 | verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n"); | |
11561 | return -EINVAL; | |
11562 | } | |
1ea47e01 | 11563 | for (i = 0; i < prog->len; i++, insn++) { |
23a2d70c | 11564 | if (!bpf_pseudo_call(insn)) |
1ea47e01 AS |
11565 | continue; |
11566 | depth = get_callee_stack_depth(env, insn, i); | |
11567 | if (depth < 0) | |
11568 | return depth; | |
11569 | bpf_patch_call_args(insn, depth); | |
11570 | } | |
19d28fbd DM |
11571 | err = 0; |
11572 | #endif | |
11573 | return err; | |
1ea47e01 AS |
11574 | } |
11575 | ||
79741b3b | 11576 | /* fixup insn->imm field of bpf_call instructions |
81ed18ab | 11577 | * and inline eligible helpers as explicit sequence of BPF instructions |
e245c5c6 AS |
11578 | * |
11579 | * this function is called after eBPF program passed verification | |
11580 | */ | |
79741b3b | 11581 | static int fixup_bpf_calls(struct bpf_verifier_env *env) |
e245c5c6 | 11582 | { |
79741b3b | 11583 | struct bpf_prog *prog = env->prog; |
d2e4c1e6 | 11584 | bool expect_blinding = bpf_jit_blinding_enabled(prog); |
79741b3b | 11585 | struct bpf_insn *insn = prog->insnsi; |
e245c5c6 | 11586 | const struct bpf_func_proto *fn; |
79741b3b | 11587 | const int insn_cnt = prog->len; |
09772d92 | 11588 | const struct bpf_map_ops *ops; |
c93552c4 | 11589 | struct bpf_insn_aux_data *aux; |
81ed18ab AS |
11590 | struct bpf_insn insn_buf[16]; |
11591 | struct bpf_prog *new_prog; | |
11592 | struct bpf_map *map_ptr; | |
d2e4c1e6 | 11593 | int i, ret, cnt, delta = 0; |
e245c5c6 | 11594 | |
79741b3b | 11595 | for (i = 0; i < insn_cnt; i++, insn++) { |
f6b1b3bf DB |
11596 | if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) || |
11597 | insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) || | |
11598 | insn->code == (BPF_ALU | BPF_MOD | BPF_X) || | |
68fda450 | 11599 | insn->code == (BPF_ALU | BPF_DIV | BPF_X)) { |
f6b1b3bf | 11600 | bool is64 = BPF_CLASS(insn->code) == BPF_ALU64; |
e88b2c6e DB |
11601 | bool isdiv = BPF_OP(insn->code) == BPF_DIV; |
11602 | struct bpf_insn *patchlet; | |
11603 | struct bpf_insn chk_and_div[] = { | |
9b00f1b7 | 11604 | /* [R,W]x div 0 -> 0 */ |
e88b2c6e DB |
11605 | BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | |
11606 | BPF_JNE | BPF_K, insn->src_reg, | |
11607 | 0, 2, 0), | |
f6b1b3bf DB |
11608 | BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg), |
11609 | BPF_JMP_IMM(BPF_JA, 0, 0, 1), | |
11610 | *insn, | |
11611 | }; | |
e88b2c6e | 11612 | struct bpf_insn chk_and_mod[] = { |
9b00f1b7 | 11613 | /* [R,W]x mod 0 -> [R,W]x */ |
e88b2c6e DB |
11614 | BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | |
11615 | BPF_JEQ | BPF_K, insn->src_reg, | |
9b00f1b7 | 11616 | 0, 1 + (is64 ? 0 : 1), 0), |
f6b1b3bf | 11617 | *insn, |
9b00f1b7 DB |
11618 | BPF_JMP_IMM(BPF_JA, 0, 0, 1), |
11619 | BPF_MOV32_REG(insn->dst_reg, insn->dst_reg), | |
f6b1b3bf | 11620 | }; |
f6b1b3bf | 11621 | |
e88b2c6e DB |
11622 | patchlet = isdiv ? chk_and_div : chk_and_mod; |
11623 | cnt = isdiv ? ARRAY_SIZE(chk_and_div) : | |
9b00f1b7 | 11624 | ARRAY_SIZE(chk_and_mod) - (is64 ? 2 : 0); |
f6b1b3bf DB |
11625 | |
11626 | new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt); | |
68fda450 AS |
11627 | if (!new_prog) |
11628 | return -ENOMEM; | |
11629 | ||
11630 | delta += cnt - 1; | |
11631 | env->prog = prog = new_prog; | |
11632 | insn = new_prog->insnsi + i + delta; | |
11633 | continue; | |
11634 | } | |
11635 | ||
e0cea7ce DB |
11636 | if (BPF_CLASS(insn->code) == BPF_LD && |
11637 | (BPF_MODE(insn->code) == BPF_ABS || | |
11638 | BPF_MODE(insn->code) == BPF_IND)) { | |
11639 | cnt = env->ops->gen_ld_abs(insn, insn_buf); | |
11640 | if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) { | |
11641 | verbose(env, "bpf verifier is misconfigured\n"); | |
11642 | return -EINVAL; | |
11643 | } | |
11644 | ||
11645 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); | |
11646 | if (!new_prog) | |
11647 | return -ENOMEM; | |
11648 | ||
11649 | delta += cnt - 1; | |
11650 | env->prog = prog = new_prog; | |
11651 | insn = new_prog->insnsi + i + delta; | |
11652 | continue; | |
11653 | } | |
11654 | ||
979d63d5 DB |
11655 | if (insn->code == (BPF_ALU64 | BPF_ADD | BPF_X) || |
11656 | insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) { | |
11657 | const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X; | |
11658 | const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X; | |
11659 | struct bpf_insn insn_buf[16]; | |
11660 | struct bpf_insn *patch = &insn_buf[0]; | |
11661 | bool issrc, isneg; | |
11662 | u32 off_reg; | |
11663 | ||
11664 | aux = &env->insn_aux_data[i + delta]; | |
3612af78 DB |
11665 | if (!aux->alu_state || |
11666 | aux->alu_state == BPF_ALU_NON_POINTER) | |
979d63d5 DB |
11667 | continue; |
11668 | ||
11669 | isneg = aux->alu_state & BPF_ALU_NEG_VALUE; | |
11670 | issrc = (aux->alu_state & BPF_ALU_SANITIZE) == | |
11671 | BPF_ALU_SANITIZE_SRC; | |
11672 | ||
11673 | off_reg = issrc ? insn->src_reg : insn->dst_reg; | |
11674 | if (isneg) | |
11675 | *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1); | |
b5871dca | 11676 | *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit); |
979d63d5 DB |
11677 | *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg); |
11678 | *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg); | |
11679 | *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0); | |
11680 | *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63); | |
11681 | if (issrc) { | |
11682 | *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX, | |
11683 | off_reg); | |
11684 | insn->src_reg = BPF_REG_AX; | |
11685 | } else { | |
11686 | *patch++ = BPF_ALU64_REG(BPF_AND, off_reg, | |
11687 | BPF_REG_AX); | |
11688 | } | |
11689 | if (isneg) | |
11690 | insn->code = insn->code == code_add ? | |
11691 | code_sub : code_add; | |
11692 | *patch++ = *insn; | |
11693 | if (issrc && isneg) | |
11694 | *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1); | |
11695 | cnt = patch - insn_buf; | |
11696 | ||
11697 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); | |
11698 | if (!new_prog) | |
11699 | return -ENOMEM; | |
11700 | ||
11701 | delta += cnt - 1; | |
11702 | env->prog = prog = new_prog; | |
11703 | insn = new_prog->insnsi + i + delta; | |
11704 | continue; | |
11705 | } | |
11706 | ||
79741b3b AS |
11707 | if (insn->code != (BPF_JMP | BPF_CALL)) |
11708 | continue; | |
cc8b0b92 AS |
11709 | if (insn->src_reg == BPF_PSEUDO_CALL) |
11710 | continue; | |
e245c5c6 | 11711 | |
79741b3b AS |
11712 | if (insn->imm == BPF_FUNC_get_route_realm) |
11713 | prog->dst_needed = 1; | |
11714 | if (insn->imm == BPF_FUNC_get_prandom_u32) | |
11715 | bpf_user_rnd_init_once(); | |
9802d865 JB |
11716 | if (insn->imm == BPF_FUNC_override_return) |
11717 | prog->kprobe_override = 1; | |
79741b3b | 11718 | if (insn->imm == BPF_FUNC_tail_call) { |
7b9f6da1 DM |
11719 | /* If we tail call into other programs, we |
11720 | * cannot make any assumptions since they can | |
11721 | * be replaced dynamically during runtime in | |
11722 | * the program array. | |
11723 | */ | |
11724 | prog->cb_access = 1; | |
e411901c MF |
11725 | if (!allow_tail_call_in_subprogs(env)) |
11726 | prog->aux->stack_depth = MAX_BPF_STACK; | |
11727 | prog->aux->max_pkt_offset = MAX_PACKET_OFF; | |
7b9f6da1 | 11728 | |
79741b3b AS |
11729 | /* mark bpf_tail_call as different opcode to avoid |
11730 | * conditional branch in the interpeter for every normal | |
11731 | * call and to prevent accidental JITing by JIT compiler | |
11732 | * that doesn't support bpf_tail_call yet | |
e245c5c6 | 11733 | */ |
79741b3b | 11734 | insn->imm = 0; |
71189fa9 | 11735 | insn->code = BPF_JMP | BPF_TAIL_CALL; |
b2157399 | 11736 | |
c93552c4 | 11737 | aux = &env->insn_aux_data[i + delta]; |
2c78ee89 | 11738 | if (env->bpf_capable && !expect_blinding && |
cc52d914 | 11739 | prog->jit_requested && |
d2e4c1e6 DB |
11740 | !bpf_map_key_poisoned(aux) && |
11741 | !bpf_map_ptr_poisoned(aux) && | |
11742 | !bpf_map_ptr_unpriv(aux)) { | |
11743 | struct bpf_jit_poke_descriptor desc = { | |
11744 | .reason = BPF_POKE_REASON_TAIL_CALL, | |
11745 | .tail_call.map = BPF_MAP_PTR(aux->map_ptr_state), | |
11746 | .tail_call.key = bpf_map_key_immediate(aux), | |
a748c697 | 11747 | .insn_idx = i + delta, |
d2e4c1e6 DB |
11748 | }; |
11749 | ||
11750 | ret = bpf_jit_add_poke_descriptor(prog, &desc); | |
11751 | if (ret < 0) { | |
11752 | verbose(env, "adding tail call poke descriptor failed\n"); | |
11753 | return ret; | |
11754 | } | |
11755 | ||
11756 | insn->imm = ret + 1; | |
11757 | continue; | |
11758 | } | |
11759 | ||
c93552c4 DB |
11760 | if (!bpf_map_ptr_unpriv(aux)) |
11761 | continue; | |
11762 | ||
b2157399 AS |
11763 | /* instead of changing every JIT dealing with tail_call |
11764 | * emit two extra insns: | |
11765 | * if (index >= max_entries) goto out; | |
11766 | * index &= array->index_mask; | |
11767 | * to avoid out-of-bounds cpu speculation | |
11768 | */ | |
c93552c4 | 11769 | if (bpf_map_ptr_poisoned(aux)) { |
40950343 | 11770 | verbose(env, "tail_call abusing map_ptr\n"); |
b2157399 AS |
11771 | return -EINVAL; |
11772 | } | |
c93552c4 | 11773 | |
d2e4c1e6 | 11774 | map_ptr = BPF_MAP_PTR(aux->map_ptr_state); |
b2157399 AS |
11775 | insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3, |
11776 | map_ptr->max_entries, 2); | |
11777 | insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3, | |
11778 | container_of(map_ptr, | |
11779 | struct bpf_array, | |
11780 | map)->index_mask); | |
11781 | insn_buf[2] = *insn; | |
11782 | cnt = 3; | |
11783 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); | |
11784 | if (!new_prog) | |
11785 | return -ENOMEM; | |
11786 | ||
11787 | delta += cnt - 1; | |
11788 | env->prog = prog = new_prog; | |
11789 | insn = new_prog->insnsi + i + delta; | |
79741b3b AS |
11790 | continue; |
11791 | } | |
e245c5c6 | 11792 | |
89c63074 | 11793 | /* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup |
09772d92 DB |
11794 | * and other inlining handlers are currently limited to 64 bit |
11795 | * only. | |
89c63074 | 11796 | */ |
60b58afc | 11797 | if (prog->jit_requested && BITS_PER_LONG == 64 && |
09772d92 DB |
11798 | (insn->imm == BPF_FUNC_map_lookup_elem || |
11799 | insn->imm == BPF_FUNC_map_update_elem || | |
84430d42 DB |
11800 | insn->imm == BPF_FUNC_map_delete_elem || |
11801 | insn->imm == BPF_FUNC_map_push_elem || | |
11802 | insn->imm == BPF_FUNC_map_pop_elem || | |
11803 | insn->imm == BPF_FUNC_map_peek_elem)) { | |
c93552c4 DB |
11804 | aux = &env->insn_aux_data[i + delta]; |
11805 | if (bpf_map_ptr_poisoned(aux)) | |
11806 | goto patch_call_imm; | |
11807 | ||
d2e4c1e6 | 11808 | map_ptr = BPF_MAP_PTR(aux->map_ptr_state); |
09772d92 DB |
11809 | ops = map_ptr->ops; |
11810 | if (insn->imm == BPF_FUNC_map_lookup_elem && | |
11811 | ops->map_gen_lookup) { | |
11812 | cnt = ops->map_gen_lookup(map_ptr, insn_buf); | |
4a8f87e6 DB |
11813 | if (cnt == -EOPNOTSUPP) |
11814 | goto patch_map_ops_generic; | |
11815 | if (cnt <= 0 || cnt >= ARRAY_SIZE(insn_buf)) { | |
09772d92 DB |
11816 | verbose(env, "bpf verifier is misconfigured\n"); |
11817 | return -EINVAL; | |
11818 | } | |
81ed18ab | 11819 | |
09772d92 DB |
11820 | new_prog = bpf_patch_insn_data(env, i + delta, |
11821 | insn_buf, cnt); | |
11822 | if (!new_prog) | |
11823 | return -ENOMEM; | |
81ed18ab | 11824 | |
09772d92 DB |
11825 | delta += cnt - 1; |
11826 | env->prog = prog = new_prog; | |
11827 | insn = new_prog->insnsi + i + delta; | |
11828 | continue; | |
11829 | } | |
81ed18ab | 11830 | |
09772d92 DB |
11831 | BUILD_BUG_ON(!__same_type(ops->map_lookup_elem, |
11832 | (void *(*)(struct bpf_map *map, void *key))NULL)); | |
11833 | BUILD_BUG_ON(!__same_type(ops->map_delete_elem, | |
11834 | (int (*)(struct bpf_map *map, void *key))NULL)); | |
11835 | BUILD_BUG_ON(!__same_type(ops->map_update_elem, | |
11836 | (int (*)(struct bpf_map *map, void *key, void *value, | |
11837 | u64 flags))NULL)); | |
84430d42 DB |
11838 | BUILD_BUG_ON(!__same_type(ops->map_push_elem, |
11839 | (int (*)(struct bpf_map *map, void *value, | |
11840 | u64 flags))NULL)); | |
11841 | BUILD_BUG_ON(!__same_type(ops->map_pop_elem, | |
11842 | (int (*)(struct bpf_map *map, void *value))NULL)); | |
11843 | BUILD_BUG_ON(!__same_type(ops->map_peek_elem, | |
11844 | (int (*)(struct bpf_map *map, void *value))NULL)); | |
4a8f87e6 | 11845 | patch_map_ops_generic: |
09772d92 DB |
11846 | switch (insn->imm) { |
11847 | case BPF_FUNC_map_lookup_elem: | |
11848 | insn->imm = BPF_CAST_CALL(ops->map_lookup_elem) - | |
11849 | __bpf_call_base; | |
11850 | continue; | |
11851 | case BPF_FUNC_map_update_elem: | |
11852 | insn->imm = BPF_CAST_CALL(ops->map_update_elem) - | |
11853 | __bpf_call_base; | |
11854 | continue; | |
11855 | case BPF_FUNC_map_delete_elem: | |
11856 | insn->imm = BPF_CAST_CALL(ops->map_delete_elem) - | |
11857 | __bpf_call_base; | |
11858 | continue; | |
84430d42 DB |
11859 | case BPF_FUNC_map_push_elem: |
11860 | insn->imm = BPF_CAST_CALL(ops->map_push_elem) - | |
11861 | __bpf_call_base; | |
11862 | continue; | |
11863 | case BPF_FUNC_map_pop_elem: | |
11864 | insn->imm = BPF_CAST_CALL(ops->map_pop_elem) - | |
11865 | __bpf_call_base; | |
11866 | continue; | |
11867 | case BPF_FUNC_map_peek_elem: | |
11868 | insn->imm = BPF_CAST_CALL(ops->map_peek_elem) - | |
11869 | __bpf_call_base; | |
11870 | continue; | |
09772d92 | 11871 | } |
81ed18ab | 11872 | |
09772d92 | 11873 | goto patch_call_imm; |
81ed18ab AS |
11874 | } |
11875 | ||
5576b991 MKL |
11876 | if (prog->jit_requested && BITS_PER_LONG == 64 && |
11877 | insn->imm == BPF_FUNC_jiffies64) { | |
11878 | struct bpf_insn ld_jiffies_addr[2] = { | |
11879 | BPF_LD_IMM64(BPF_REG_0, | |
11880 | (unsigned long)&jiffies), | |
11881 | }; | |
11882 | ||
11883 | insn_buf[0] = ld_jiffies_addr[0]; | |
11884 | insn_buf[1] = ld_jiffies_addr[1]; | |
11885 | insn_buf[2] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, | |
11886 | BPF_REG_0, 0); | |
11887 | cnt = 3; | |
11888 | ||
11889 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, | |
11890 | cnt); | |
11891 | if (!new_prog) | |
11892 | return -ENOMEM; | |
11893 | ||
11894 | delta += cnt - 1; | |
11895 | env->prog = prog = new_prog; | |
11896 | insn = new_prog->insnsi + i + delta; | |
11897 | continue; | |
11898 | } | |
11899 | ||
81ed18ab | 11900 | patch_call_imm: |
5e43f899 | 11901 | fn = env->ops->get_func_proto(insn->imm, env->prog); |
79741b3b AS |
11902 | /* all functions that have prototype and verifier allowed |
11903 | * programs to call them, must be real in-kernel functions | |
11904 | */ | |
11905 | if (!fn->func) { | |
61bd5218 JK |
11906 | verbose(env, |
11907 | "kernel subsystem misconfigured func %s#%d\n", | |
79741b3b AS |
11908 | func_id_name(insn->imm), insn->imm); |
11909 | return -EFAULT; | |
e245c5c6 | 11910 | } |
79741b3b | 11911 | insn->imm = fn->func - __bpf_call_base; |
e245c5c6 | 11912 | } |
e245c5c6 | 11913 | |
d2e4c1e6 DB |
11914 | /* Since poke tab is now finalized, publish aux to tracker. */ |
11915 | for (i = 0; i < prog->aux->size_poke_tab; i++) { | |
11916 | map_ptr = prog->aux->poke_tab[i].tail_call.map; | |
11917 | if (!map_ptr->ops->map_poke_track || | |
11918 | !map_ptr->ops->map_poke_untrack || | |
11919 | !map_ptr->ops->map_poke_run) { | |
11920 | verbose(env, "bpf verifier is misconfigured\n"); | |
11921 | return -EINVAL; | |
11922 | } | |
11923 | ||
11924 | ret = map_ptr->ops->map_poke_track(map_ptr, prog->aux); | |
11925 | if (ret < 0) { | |
11926 | verbose(env, "tracking tail call prog failed\n"); | |
11927 | return ret; | |
11928 | } | |
11929 | } | |
11930 | ||
79741b3b AS |
11931 | return 0; |
11932 | } | |
e245c5c6 | 11933 | |
58e2af8b | 11934 | static void free_states(struct bpf_verifier_env *env) |
f1bca824 | 11935 | { |
58e2af8b | 11936 | struct bpf_verifier_state_list *sl, *sln; |
f1bca824 AS |
11937 | int i; |
11938 | ||
9f4686c4 AS |
11939 | sl = env->free_list; |
11940 | while (sl) { | |
11941 | sln = sl->next; | |
11942 | free_verifier_state(&sl->state, false); | |
11943 | kfree(sl); | |
11944 | sl = sln; | |
11945 | } | |
51c39bb1 | 11946 | env->free_list = NULL; |
9f4686c4 | 11947 | |
f1bca824 AS |
11948 | if (!env->explored_states) |
11949 | return; | |
11950 | ||
dc2a4ebc | 11951 | for (i = 0; i < state_htab_size(env); i++) { |
f1bca824 AS |
11952 | sl = env->explored_states[i]; |
11953 | ||
a8f500af AS |
11954 | while (sl) { |
11955 | sln = sl->next; | |
11956 | free_verifier_state(&sl->state, false); | |
11957 | kfree(sl); | |
11958 | sl = sln; | |
11959 | } | |
51c39bb1 | 11960 | env->explored_states[i] = NULL; |
f1bca824 | 11961 | } |
51c39bb1 | 11962 | } |
f1bca824 | 11963 | |
51c39bb1 AS |
11964 | /* The verifier is using insn_aux_data[] to store temporary data during |
11965 | * verification and to store information for passes that run after the | |
11966 | * verification like dead code sanitization. do_check_common() for subprogram N | |
11967 | * may analyze many other subprograms. sanitize_insn_aux_data() clears all | |
11968 | * temporary data after do_check_common() finds that subprogram N cannot be | |
11969 | * verified independently. pass_cnt counts the number of times | |
11970 | * do_check_common() was run and insn->aux->seen tells the pass number | |
11971 | * insn_aux_data was touched. These variables are compared to clear temporary | |
11972 | * data from failed pass. For testing and experiments do_check_common() can be | |
11973 | * run multiple times even when prior attempt to verify is unsuccessful. | |
11974 | */ | |
11975 | static void sanitize_insn_aux_data(struct bpf_verifier_env *env) | |
11976 | { | |
11977 | struct bpf_insn *insn = env->prog->insnsi; | |
11978 | struct bpf_insn_aux_data *aux; | |
11979 | int i, class; | |
11980 | ||
11981 | for (i = 0; i < env->prog->len; i++) { | |
11982 | class = BPF_CLASS(insn[i].code); | |
11983 | if (class != BPF_LDX && class != BPF_STX) | |
11984 | continue; | |
11985 | aux = &env->insn_aux_data[i]; | |
11986 | if (aux->seen != env->pass_cnt) | |
11987 | continue; | |
11988 | memset(aux, 0, offsetof(typeof(*aux), orig_idx)); | |
11989 | } | |
f1bca824 AS |
11990 | } |
11991 | ||
51c39bb1 AS |
11992 | static int do_check_common(struct bpf_verifier_env *env, int subprog) |
11993 | { | |
6f8a57cc | 11994 | bool pop_log = !(env->log.level & BPF_LOG_LEVEL2); |
51c39bb1 AS |
11995 | struct bpf_verifier_state *state; |
11996 | struct bpf_reg_state *regs; | |
11997 | int ret, i; | |
11998 | ||
11999 | env->prev_linfo = NULL; | |
12000 | env->pass_cnt++; | |
12001 | ||
12002 | state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL); | |
12003 | if (!state) | |
12004 | return -ENOMEM; | |
12005 | state->curframe = 0; | |
12006 | state->speculative = false; | |
12007 | state->branches = 1; | |
12008 | state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL); | |
12009 | if (!state->frame[0]) { | |
12010 | kfree(state); | |
12011 | return -ENOMEM; | |
12012 | } | |
12013 | env->cur_state = state; | |
12014 | init_func_state(env, state->frame[0], | |
12015 | BPF_MAIN_FUNC /* callsite */, | |
12016 | 0 /* frameno */, | |
12017 | subprog); | |
12018 | ||
12019 | regs = state->frame[state->curframe]->regs; | |
be8704ff | 12020 | if (subprog || env->prog->type == BPF_PROG_TYPE_EXT) { |
51c39bb1 AS |
12021 | ret = btf_prepare_func_args(env, subprog, regs); |
12022 | if (ret) | |
12023 | goto out; | |
12024 | for (i = BPF_REG_1; i <= BPF_REG_5; i++) { | |
12025 | if (regs[i].type == PTR_TO_CTX) | |
12026 | mark_reg_known_zero(env, regs, i); | |
12027 | else if (regs[i].type == SCALAR_VALUE) | |
12028 | mark_reg_unknown(env, regs, i); | |
e5069b9c DB |
12029 | else if (regs[i].type == PTR_TO_MEM_OR_NULL) { |
12030 | const u32 mem_size = regs[i].mem_size; | |
12031 | ||
12032 | mark_reg_known_zero(env, regs, i); | |
12033 | regs[i].mem_size = mem_size; | |
12034 | regs[i].id = ++env->id_gen; | |
12035 | } | |
51c39bb1 AS |
12036 | } |
12037 | } else { | |
12038 | /* 1st arg to a function */ | |
12039 | regs[BPF_REG_1].type = PTR_TO_CTX; | |
12040 | mark_reg_known_zero(env, regs, BPF_REG_1); | |
12041 | ret = btf_check_func_arg_match(env, subprog, regs); | |
12042 | if (ret == -EFAULT) | |
12043 | /* unlikely verifier bug. abort. | |
12044 | * ret == 0 and ret < 0 are sadly acceptable for | |
12045 | * main() function due to backward compatibility. | |
12046 | * Like socket filter program may be written as: | |
12047 | * int bpf_prog(struct pt_regs *ctx) | |
12048 | * and never dereference that ctx in the program. | |
12049 | * 'struct pt_regs' is a type mismatch for socket | |
12050 | * filter that should be using 'struct __sk_buff'. | |
12051 | */ | |
12052 | goto out; | |
12053 | } | |
12054 | ||
12055 | ret = do_check(env); | |
12056 | out: | |
f59bbfc2 AS |
12057 | /* check for NULL is necessary, since cur_state can be freed inside |
12058 | * do_check() under memory pressure. | |
12059 | */ | |
12060 | if (env->cur_state) { | |
12061 | free_verifier_state(env->cur_state, true); | |
12062 | env->cur_state = NULL; | |
12063 | } | |
6f8a57cc AN |
12064 | while (!pop_stack(env, NULL, NULL, false)); |
12065 | if (!ret && pop_log) | |
12066 | bpf_vlog_reset(&env->log, 0); | |
51c39bb1 AS |
12067 | free_states(env); |
12068 | if (ret) | |
12069 | /* clean aux data in case subprog was rejected */ | |
12070 | sanitize_insn_aux_data(env); | |
12071 | return ret; | |
12072 | } | |
12073 | ||
12074 | /* Verify all global functions in a BPF program one by one based on their BTF. | |
12075 | * All global functions must pass verification. Otherwise the whole program is rejected. | |
12076 | * Consider: | |
12077 | * int bar(int); | |
12078 | * int foo(int f) | |
12079 | * { | |
12080 | * return bar(f); | |
12081 | * } | |
12082 | * int bar(int b) | |
12083 | * { | |
12084 | * ... | |
12085 | * } | |
12086 | * foo() will be verified first for R1=any_scalar_value. During verification it | |
12087 | * will be assumed that bar() already verified successfully and call to bar() | |
12088 | * from foo() will be checked for type match only. Later bar() will be verified | |
12089 | * independently to check that it's safe for R1=any_scalar_value. | |
12090 | */ | |
12091 | static int do_check_subprogs(struct bpf_verifier_env *env) | |
12092 | { | |
12093 | struct bpf_prog_aux *aux = env->prog->aux; | |
12094 | int i, ret; | |
12095 | ||
12096 | if (!aux->func_info) | |
12097 | return 0; | |
12098 | ||
12099 | for (i = 1; i < env->subprog_cnt; i++) { | |
12100 | if (aux->func_info_aux[i].linkage != BTF_FUNC_GLOBAL) | |
12101 | continue; | |
12102 | env->insn_idx = env->subprog_info[i].start; | |
12103 | WARN_ON_ONCE(env->insn_idx == 0); | |
12104 | ret = do_check_common(env, i); | |
12105 | if (ret) { | |
12106 | return ret; | |
12107 | } else if (env->log.level & BPF_LOG_LEVEL) { | |
12108 | verbose(env, | |
12109 | "Func#%d is safe for any args that match its prototype\n", | |
12110 | i); | |
12111 | } | |
12112 | } | |
12113 | return 0; | |
12114 | } | |
12115 | ||
12116 | static int do_check_main(struct bpf_verifier_env *env) | |
12117 | { | |
12118 | int ret; | |
12119 | ||
12120 | env->insn_idx = 0; | |
12121 | ret = do_check_common(env, 0); | |
12122 | if (!ret) | |
12123 | env->prog->aux->stack_depth = env->subprog_info[0].stack_depth; | |
12124 | return ret; | |
12125 | } | |
12126 | ||
12127 | ||
06ee7115 AS |
12128 | static void print_verification_stats(struct bpf_verifier_env *env) |
12129 | { | |
12130 | int i; | |
12131 | ||
12132 | if (env->log.level & BPF_LOG_STATS) { | |
12133 | verbose(env, "verification time %lld usec\n", | |
12134 | div_u64(env->verification_time, 1000)); | |
12135 | verbose(env, "stack depth "); | |
12136 | for (i = 0; i < env->subprog_cnt; i++) { | |
12137 | u32 depth = env->subprog_info[i].stack_depth; | |
12138 | ||
12139 | verbose(env, "%d", depth); | |
12140 | if (i + 1 < env->subprog_cnt) | |
12141 | verbose(env, "+"); | |
12142 | } | |
12143 | verbose(env, "\n"); | |
12144 | } | |
12145 | verbose(env, "processed %d insns (limit %d) max_states_per_insn %d " | |
12146 | "total_states %d peak_states %d mark_read %d\n", | |
12147 | env->insn_processed, BPF_COMPLEXITY_LIMIT_INSNS, | |
12148 | env->max_states_per_insn, env->total_states, | |
12149 | env->peak_states, env->longest_mark_read_walk); | |
f1bca824 AS |
12150 | } |
12151 | ||
27ae7997 MKL |
12152 | static int check_struct_ops_btf_id(struct bpf_verifier_env *env) |
12153 | { | |
12154 | const struct btf_type *t, *func_proto; | |
12155 | const struct bpf_struct_ops *st_ops; | |
12156 | const struct btf_member *member; | |
12157 | struct bpf_prog *prog = env->prog; | |
12158 | u32 btf_id, member_idx; | |
12159 | const char *mname; | |
12160 | ||
12aa8a94 THJ |
12161 | if (!prog->gpl_compatible) { |
12162 | verbose(env, "struct ops programs must have a GPL compatible license\n"); | |
12163 | return -EINVAL; | |
12164 | } | |
12165 | ||
27ae7997 MKL |
12166 | btf_id = prog->aux->attach_btf_id; |
12167 | st_ops = bpf_struct_ops_find(btf_id); | |
12168 | if (!st_ops) { | |
12169 | verbose(env, "attach_btf_id %u is not a supported struct\n", | |
12170 | btf_id); | |
12171 | return -ENOTSUPP; | |
12172 | } | |
12173 | ||
12174 | t = st_ops->type; | |
12175 | member_idx = prog->expected_attach_type; | |
12176 | if (member_idx >= btf_type_vlen(t)) { | |
12177 | verbose(env, "attach to invalid member idx %u of struct %s\n", | |
12178 | member_idx, st_ops->name); | |
12179 | return -EINVAL; | |
12180 | } | |
12181 | ||
12182 | member = &btf_type_member(t)[member_idx]; | |
12183 | mname = btf_name_by_offset(btf_vmlinux, member->name_off); | |
12184 | func_proto = btf_type_resolve_func_ptr(btf_vmlinux, member->type, | |
12185 | NULL); | |
12186 | if (!func_proto) { | |
12187 | verbose(env, "attach to invalid member %s(@idx %u) of struct %s\n", | |
12188 | mname, member_idx, st_ops->name); | |
12189 | return -EINVAL; | |
12190 | } | |
12191 | ||
12192 | if (st_ops->check_member) { | |
12193 | int err = st_ops->check_member(t, member); | |
12194 | ||
12195 | if (err) { | |
12196 | verbose(env, "attach to unsupported member %s of struct %s\n", | |
12197 | mname, st_ops->name); | |
12198 | return err; | |
12199 | } | |
12200 | } | |
12201 | ||
12202 | prog->aux->attach_func_proto = func_proto; | |
12203 | prog->aux->attach_func_name = mname; | |
12204 | env->ops = st_ops->verifier_ops; | |
12205 | ||
12206 | return 0; | |
12207 | } | |
6ba43b76 KS |
12208 | #define SECURITY_PREFIX "security_" |
12209 | ||
f7b12b6f | 12210 | static int check_attach_modify_return(unsigned long addr, const char *func_name) |
6ba43b76 | 12211 | { |
69191754 | 12212 | if (within_error_injection_list(addr) || |
f7b12b6f | 12213 | !strncmp(SECURITY_PREFIX, func_name, sizeof(SECURITY_PREFIX) - 1)) |
6ba43b76 | 12214 | return 0; |
6ba43b76 | 12215 | |
6ba43b76 KS |
12216 | return -EINVAL; |
12217 | } | |
27ae7997 | 12218 | |
1e6c62a8 AS |
12219 | /* list of non-sleepable functions that are otherwise on |
12220 | * ALLOW_ERROR_INJECTION list | |
12221 | */ | |
12222 | BTF_SET_START(btf_non_sleepable_error_inject) | |
12223 | /* Three functions below can be called from sleepable and non-sleepable context. | |
12224 | * Assume non-sleepable from bpf safety point of view. | |
12225 | */ | |
12226 | BTF_ID(func, __add_to_page_cache_locked) | |
12227 | BTF_ID(func, should_fail_alloc_page) | |
12228 | BTF_ID(func, should_failslab) | |
12229 | BTF_SET_END(btf_non_sleepable_error_inject) | |
12230 | ||
12231 | static int check_non_sleepable_error_inject(u32 btf_id) | |
12232 | { | |
12233 | return btf_id_set_contains(&btf_non_sleepable_error_inject, btf_id); | |
12234 | } | |
12235 | ||
f7b12b6f THJ |
12236 | int bpf_check_attach_target(struct bpf_verifier_log *log, |
12237 | const struct bpf_prog *prog, | |
12238 | const struct bpf_prog *tgt_prog, | |
12239 | u32 btf_id, | |
12240 | struct bpf_attach_target_info *tgt_info) | |
38207291 | 12241 | { |
be8704ff | 12242 | bool prog_extension = prog->type == BPF_PROG_TYPE_EXT; |
f1b9509c | 12243 | const char prefix[] = "btf_trace_"; |
5b92a28a | 12244 | int ret = 0, subprog = -1, i; |
38207291 | 12245 | const struct btf_type *t; |
5b92a28a | 12246 | bool conservative = true; |
38207291 | 12247 | const char *tname; |
5b92a28a | 12248 | struct btf *btf; |
f7b12b6f | 12249 | long addr = 0; |
38207291 | 12250 | |
f1b9509c | 12251 | if (!btf_id) { |
efc68158 | 12252 | bpf_log(log, "Tracing programs must provide btf_id\n"); |
f1b9509c AS |
12253 | return -EINVAL; |
12254 | } | |
22dc4a0f | 12255 | btf = tgt_prog ? tgt_prog->aux->btf : prog->aux->attach_btf; |
5b92a28a | 12256 | if (!btf) { |
efc68158 | 12257 | bpf_log(log, |
5b92a28a AS |
12258 | "FENTRY/FEXIT program can only be attached to another program annotated with BTF\n"); |
12259 | return -EINVAL; | |
12260 | } | |
12261 | t = btf_type_by_id(btf, btf_id); | |
f1b9509c | 12262 | if (!t) { |
efc68158 | 12263 | bpf_log(log, "attach_btf_id %u is invalid\n", btf_id); |
f1b9509c AS |
12264 | return -EINVAL; |
12265 | } | |
5b92a28a | 12266 | tname = btf_name_by_offset(btf, t->name_off); |
f1b9509c | 12267 | if (!tname) { |
efc68158 | 12268 | bpf_log(log, "attach_btf_id %u doesn't have a name\n", btf_id); |
f1b9509c AS |
12269 | return -EINVAL; |
12270 | } | |
5b92a28a AS |
12271 | if (tgt_prog) { |
12272 | struct bpf_prog_aux *aux = tgt_prog->aux; | |
12273 | ||
12274 | for (i = 0; i < aux->func_info_cnt; i++) | |
12275 | if (aux->func_info[i].type_id == btf_id) { | |
12276 | subprog = i; | |
12277 | break; | |
12278 | } | |
12279 | if (subprog == -1) { | |
efc68158 | 12280 | bpf_log(log, "Subprog %s doesn't exist\n", tname); |
5b92a28a AS |
12281 | return -EINVAL; |
12282 | } | |
12283 | conservative = aux->func_info_aux[subprog].unreliable; | |
be8704ff AS |
12284 | if (prog_extension) { |
12285 | if (conservative) { | |
efc68158 | 12286 | bpf_log(log, |
be8704ff AS |
12287 | "Cannot replace static functions\n"); |
12288 | return -EINVAL; | |
12289 | } | |
12290 | if (!prog->jit_requested) { | |
efc68158 | 12291 | bpf_log(log, |
be8704ff AS |
12292 | "Extension programs should be JITed\n"); |
12293 | return -EINVAL; | |
12294 | } | |
be8704ff AS |
12295 | } |
12296 | if (!tgt_prog->jited) { | |
efc68158 | 12297 | bpf_log(log, "Can attach to only JITed progs\n"); |
be8704ff AS |
12298 | return -EINVAL; |
12299 | } | |
12300 | if (tgt_prog->type == prog->type) { | |
12301 | /* Cannot fentry/fexit another fentry/fexit program. | |
12302 | * Cannot attach program extension to another extension. | |
12303 | * It's ok to attach fentry/fexit to extension program. | |
12304 | */ | |
efc68158 | 12305 | bpf_log(log, "Cannot recursively attach\n"); |
be8704ff AS |
12306 | return -EINVAL; |
12307 | } | |
12308 | if (tgt_prog->type == BPF_PROG_TYPE_TRACING && | |
12309 | prog_extension && | |
12310 | (tgt_prog->expected_attach_type == BPF_TRACE_FENTRY || | |
12311 | tgt_prog->expected_attach_type == BPF_TRACE_FEXIT)) { | |
12312 | /* Program extensions can extend all program types | |
12313 | * except fentry/fexit. The reason is the following. | |
12314 | * The fentry/fexit programs are used for performance | |
12315 | * analysis, stats and can be attached to any program | |
12316 | * type except themselves. When extension program is | |
12317 | * replacing XDP function it is necessary to allow | |
12318 | * performance analysis of all functions. Both original | |
12319 | * XDP program and its program extension. Hence | |
12320 | * attaching fentry/fexit to BPF_PROG_TYPE_EXT is | |
12321 | * allowed. If extending of fentry/fexit was allowed it | |
12322 | * would be possible to create long call chain | |
12323 | * fentry->extension->fentry->extension beyond | |
12324 | * reasonable stack size. Hence extending fentry is not | |
12325 | * allowed. | |
12326 | */ | |
efc68158 | 12327 | bpf_log(log, "Cannot extend fentry/fexit\n"); |
be8704ff AS |
12328 | return -EINVAL; |
12329 | } | |
5b92a28a | 12330 | } else { |
be8704ff | 12331 | if (prog_extension) { |
efc68158 | 12332 | bpf_log(log, "Cannot replace kernel functions\n"); |
be8704ff AS |
12333 | return -EINVAL; |
12334 | } | |
5b92a28a | 12335 | } |
f1b9509c AS |
12336 | |
12337 | switch (prog->expected_attach_type) { | |
12338 | case BPF_TRACE_RAW_TP: | |
5b92a28a | 12339 | if (tgt_prog) { |
efc68158 | 12340 | bpf_log(log, |
5b92a28a AS |
12341 | "Only FENTRY/FEXIT progs are attachable to another BPF prog\n"); |
12342 | return -EINVAL; | |
12343 | } | |
38207291 | 12344 | if (!btf_type_is_typedef(t)) { |
efc68158 | 12345 | bpf_log(log, "attach_btf_id %u is not a typedef\n", |
38207291 MKL |
12346 | btf_id); |
12347 | return -EINVAL; | |
12348 | } | |
f1b9509c | 12349 | if (strncmp(prefix, tname, sizeof(prefix) - 1)) { |
efc68158 | 12350 | bpf_log(log, "attach_btf_id %u points to wrong type name %s\n", |
38207291 MKL |
12351 | btf_id, tname); |
12352 | return -EINVAL; | |
12353 | } | |
12354 | tname += sizeof(prefix) - 1; | |
5b92a28a | 12355 | t = btf_type_by_id(btf, t->type); |
38207291 MKL |
12356 | if (!btf_type_is_ptr(t)) |
12357 | /* should never happen in valid vmlinux build */ | |
12358 | return -EINVAL; | |
5b92a28a | 12359 | t = btf_type_by_id(btf, t->type); |
38207291 MKL |
12360 | if (!btf_type_is_func_proto(t)) |
12361 | /* should never happen in valid vmlinux build */ | |
12362 | return -EINVAL; | |
12363 | ||
f7b12b6f | 12364 | break; |
15d83c4d YS |
12365 | case BPF_TRACE_ITER: |
12366 | if (!btf_type_is_func(t)) { | |
efc68158 | 12367 | bpf_log(log, "attach_btf_id %u is not a function\n", |
15d83c4d YS |
12368 | btf_id); |
12369 | return -EINVAL; | |
12370 | } | |
12371 | t = btf_type_by_id(btf, t->type); | |
12372 | if (!btf_type_is_func_proto(t)) | |
12373 | return -EINVAL; | |
f7b12b6f THJ |
12374 | ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel); |
12375 | if (ret) | |
12376 | return ret; | |
12377 | break; | |
be8704ff AS |
12378 | default: |
12379 | if (!prog_extension) | |
12380 | return -EINVAL; | |
df561f66 | 12381 | fallthrough; |
ae240823 | 12382 | case BPF_MODIFY_RETURN: |
9e4e01df | 12383 | case BPF_LSM_MAC: |
fec56f58 AS |
12384 | case BPF_TRACE_FENTRY: |
12385 | case BPF_TRACE_FEXIT: | |
12386 | if (!btf_type_is_func(t)) { | |
efc68158 | 12387 | bpf_log(log, "attach_btf_id %u is not a function\n", |
fec56f58 AS |
12388 | btf_id); |
12389 | return -EINVAL; | |
12390 | } | |
be8704ff | 12391 | if (prog_extension && |
efc68158 | 12392 | btf_check_type_match(log, prog, btf, t)) |
be8704ff | 12393 | return -EINVAL; |
5b92a28a | 12394 | t = btf_type_by_id(btf, t->type); |
fec56f58 AS |
12395 | if (!btf_type_is_func_proto(t)) |
12396 | return -EINVAL; | |
f7b12b6f | 12397 | |
4a1e7c0c THJ |
12398 | if ((prog->aux->saved_dst_prog_type || prog->aux->saved_dst_attach_type) && |
12399 | (!tgt_prog || prog->aux->saved_dst_prog_type != tgt_prog->type || | |
12400 | prog->aux->saved_dst_attach_type != tgt_prog->expected_attach_type)) | |
12401 | return -EINVAL; | |
12402 | ||
f7b12b6f | 12403 | if (tgt_prog && conservative) |
5b92a28a | 12404 | t = NULL; |
f7b12b6f THJ |
12405 | |
12406 | ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel); | |
fec56f58 | 12407 | if (ret < 0) |
f7b12b6f THJ |
12408 | return ret; |
12409 | ||
5b92a28a | 12410 | if (tgt_prog) { |
e9eeec58 YS |
12411 | if (subprog == 0) |
12412 | addr = (long) tgt_prog->bpf_func; | |
12413 | else | |
12414 | addr = (long) tgt_prog->aux->func[subprog]->bpf_func; | |
5b92a28a AS |
12415 | } else { |
12416 | addr = kallsyms_lookup_name(tname); | |
12417 | if (!addr) { | |
efc68158 | 12418 | bpf_log(log, |
5b92a28a AS |
12419 | "The address of function %s cannot be found\n", |
12420 | tname); | |
f7b12b6f | 12421 | return -ENOENT; |
5b92a28a | 12422 | } |
fec56f58 | 12423 | } |
18644cec | 12424 | |
1e6c62a8 AS |
12425 | if (prog->aux->sleepable) { |
12426 | ret = -EINVAL; | |
12427 | switch (prog->type) { | |
12428 | case BPF_PROG_TYPE_TRACING: | |
12429 | /* fentry/fexit/fmod_ret progs can be sleepable only if they are | |
12430 | * attached to ALLOW_ERROR_INJECTION and are not in denylist. | |
12431 | */ | |
12432 | if (!check_non_sleepable_error_inject(btf_id) && | |
12433 | within_error_injection_list(addr)) | |
12434 | ret = 0; | |
12435 | break; | |
12436 | case BPF_PROG_TYPE_LSM: | |
12437 | /* LSM progs check that they are attached to bpf_lsm_*() funcs. | |
12438 | * Only some of them are sleepable. | |
12439 | */ | |
423f1610 | 12440 | if (bpf_lsm_is_sleepable_hook(btf_id)) |
1e6c62a8 AS |
12441 | ret = 0; |
12442 | break; | |
12443 | default: | |
12444 | break; | |
12445 | } | |
f7b12b6f THJ |
12446 | if (ret) { |
12447 | bpf_log(log, "%s is not sleepable\n", tname); | |
12448 | return ret; | |
12449 | } | |
1e6c62a8 | 12450 | } else if (prog->expected_attach_type == BPF_MODIFY_RETURN) { |
1af9270e | 12451 | if (tgt_prog) { |
efc68158 | 12452 | bpf_log(log, "can't modify return codes of BPF programs\n"); |
f7b12b6f THJ |
12453 | return -EINVAL; |
12454 | } | |
12455 | ret = check_attach_modify_return(addr, tname); | |
12456 | if (ret) { | |
12457 | bpf_log(log, "%s() is not modifiable\n", tname); | |
12458 | return ret; | |
1af9270e | 12459 | } |
18644cec | 12460 | } |
f7b12b6f THJ |
12461 | |
12462 | break; | |
12463 | } | |
12464 | tgt_info->tgt_addr = addr; | |
12465 | tgt_info->tgt_name = tname; | |
12466 | tgt_info->tgt_type = t; | |
12467 | return 0; | |
12468 | } | |
12469 | ||
12470 | static int check_attach_btf_id(struct bpf_verifier_env *env) | |
12471 | { | |
12472 | struct bpf_prog *prog = env->prog; | |
3aac1ead | 12473 | struct bpf_prog *tgt_prog = prog->aux->dst_prog; |
f7b12b6f THJ |
12474 | struct bpf_attach_target_info tgt_info = {}; |
12475 | u32 btf_id = prog->aux->attach_btf_id; | |
12476 | struct bpf_trampoline *tr; | |
12477 | int ret; | |
12478 | u64 key; | |
12479 | ||
12480 | if (prog->aux->sleepable && prog->type != BPF_PROG_TYPE_TRACING && | |
12481 | prog->type != BPF_PROG_TYPE_LSM) { | |
12482 | verbose(env, "Only fentry/fexit/fmod_ret and lsm programs can be sleepable\n"); | |
12483 | return -EINVAL; | |
12484 | } | |
12485 | ||
12486 | if (prog->type == BPF_PROG_TYPE_STRUCT_OPS) | |
12487 | return check_struct_ops_btf_id(env); | |
12488 | ||
12489 | if (prog->type != BPF_PROG_TYPE_TRACING && | |
12490 | prog->type != BPF_PROG_TYPE_LSM && | |
12491 | prog->type != BPF_PROG_TYPE_EXT) | |
12492 | return 0; | |
12493 | ||
12494 | ret = bpf_check_attach_target(&env->log, prog, tgt_prog, btf_id, &tgt_info); | |
12495 | if (ret) | |
fec56f58 | 12496 | return ret; |
f7b12b6f THJ |
12497 | |
12498 | if (tgt_prog && prog->type == BPF_PROG_TYPE_EXT) { | |
3aac1ead THJ |
12499 | /* to make freplace equivalent to their targets, they need to |
12500 | * inherit env->ops and expected_attach_type for the rest of the | |
12501 | * verification | |
12502 | */ | |
f7b12b6f THJ |
12503 | env->ops = bpf_verifier_ops[tgt_prog->type]; |
12504 | prog->expected_attach_type = tgt_prog->expected_attach_type; | |
12505 | } | |
12506 | ||
12507 | /* store info about the attachment target that will be used later */ | |
12508 | prog->aux->attach_func_proto = tgt_info.tgt_type; | |
12509 | prog->aux->attach_func_name = tgt_info.tgt_name; | |
12510 | ||
4a1e7c0c THJ |
12511 | if (tgt_prog) { |
12512 | prog->aux->saved_dst_prog_type = tgt_prog->type; | |
12513 | prog->aux->saved_dst_attach_type = tgt_prog->expected_attach_type; | |
12514 | } | |
12515 | ||
f7b12b6f THJ |
12516 | if (prog->expected_attach_type == BPF_TRACE_RAW_TP) { |
12517 | prog->aux->attach_btf_trace = true; | |
12518 | return 0; | |
12519 | } else if (prog->expected_attach_type == BPF_TRACE_ITER) { | |
12520 | if (!bpf_iter_prog_supported(prog)) | |
12521 | return -EINVAL; | |
12522 | return 0; | |
12523 | } | |
12524 | ||
12525 | if (prog->type == BPF_PROG_TYPE_LSM) { | |
12526 | ret = bpf_lsm_verify_prog(&env->log, prog); | |
12527 | if (ret < 0) | |
12528 | return ret; | |
38207291 | 12529 | } |
f7b12b6f | 12530 | |
22dc4a0f | 12531 | key = bpf_trampoline_compute_key(tgt_prog, prog->aux->attach_btf, btf_id); |
f7b12b6f THJ |
12532 | tr = bpf_trampoline_get(key, &tgt_info); |
12533 | if (!tr) | |
12534 | return -ENOMEM; | |
12535 | ||
3aac1ead | 12536 | prog->aux->dst_trampoline = tr; |
f7b12b6f | 12537 | return 0; |
38207291 MKL |
12538 | } |
12539 | ||
76654e67 AM |
12540 | struct btf *bpf_get_btf_vmlinux(void) |
12541 | { | |
12542 | if (!btf_vmlinux && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) { | |
12543 | mutex_lock(&bpf_verifier_lock); | |
12544 | if (!btf_vmlinux) | |
12545 | btf_vmlinux = btf_parse_vmlinux(); | |
12546 | mutex_unlock(&bpf_verifier_lock); | |
12547 | } | |
12548 | return btf_vmlinux; | |
12549 | } | |
12550 | ||
838e9690 YS |
12551 | int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, |
12552 | union bpf_attr __user *uattr) | |
51580e79 | 12553 | { |
06ee7115 | 12554 | u64 start_time = ktime_get_ns(); |
58e2af8b | 12555 | struct bpf_verifier_env *env; |
b9193c1b | 12556 | struct bpf_verifier_log *log; |
9e4c24e7 | 12557 | int i, len, ret = -EINVAL; |
e2ae4ca2 | 12558 | bool is_priv; |
51580e79 | 12559 | |
eba0c929 AB |
12560 | /* no program is valid */ |
12561 | if (ARRAY_SIZE(bpf_verifier_ops) == 0) | |
12562 | return -EINVAL; | |
12563 | ||
58e2af8b | 12564 | /* 'struct bpf_verifier_env' can be global, but since it's not small, |
cbd35700 AS |
12565 | * allocate/free it every time bpf_check() is called |
12566 | */ | |
58e2af8b | 12567 | env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL); |
cbd35700 AS |
12568 | if (!env) |
12569 | return -ENOMEM; | |
61bd5218 | 12570 | log = &env->log; |
cbd35700 | 12571 | |
9e4c24e7 | 12572 | len = (*prog)->len; |
fad953ce | 12573 | env->insn_aux_data = |
9e4c24e7 | 12574 | vzalloc(array_size(sizeof(struct bpf_insn_aux_data), len)); |
3df126f3 JK |
12575 | ret = -ENOMEM; |
12576 | if (!env->insn_aux_data) | |
12577 | goto err_free_env; | |
9e4c24e7 JK |
12578 | for (i = 0; i < len; i++) |
12579 | env->insn_aux_data[i].orig_idx = i; | |
9bac3d6d | 12580 | env->prog = *prog; |
00176a34 | 12581 | env->ops = bpf_verifier_ops[env->prog->type]; |
2c78ee89 | 12582 | is_priv = bpf_capable(); |
0246e64d | 12583 | |
76654e67 | 12584 | bpf_get_btf_vmlinux(); |
8580ac94 | 12585 | |
cbd35700 | 12586 | /* grab the mutex to protect few globals used by verifier */ |
45a73c17 AS |
12587 | if (!is_priv) |
12588 | mutex_lock(&bpf_verifier_lock); | |
cbd35700 AS |
12589 | |
12590 | if (attr->log_level || attr->log_buf || attr->log_size) { | |
12591 | /* user requested verbose verifier output | |
12592 | * and supplied buffer to store the verification trace | |
12593 | */ | |
e7bf8249 JK |
12594 | log->level = attr->log_level; |
12595 | log->ubuf = (char __user *) (unsigned long) attr->log_buf; | |
12596 | log->len_total = attr->log_size; | |
cbd35700 AS |
12597 | |
12598 | ret = -EINVAL; | |
e7bf8249 | 12599 | /* log attributes have to be sane */ |
7a9f5c65 | 12600 | if (log->len_total < 128 || log->len_total > UINT_MAX >> 2 || |
06ee7115 | 12601 | !log->level || !log->ubuf || log->level & ~BPF_LOG_MASK) |
3df126f3 | 12602 | goto err_unlock; |
cbd35700 | 12603 | } |
1ad2f583 | 12604 | |
8580ac94 AS |
12605 | if (IS_ERR(btf_vmlinux)) { |
12606 | /* Either gcc or pahole or kernel are broken. */ | |
12607 | verbose(env, "in-kernel BTF is malformed\n"); | |
12608 | ret = PTR_ERR(btf_vmlinux); | |
38207291 | 12609 | goto skip_full_check; |
8580ac94 AS |
12610 | } |
12611 | ||
1ad2f583 DB |
12612 | env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT); |
12613 | if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) | |
e07b98d9 | 12614 | env->strict_alignment = true; |
e9ee9efc DM |
12615 | if (attr->prog_flags & BPF_F_ANY_ALIGNMENT) |
12616 | env->strict_alignment = false; | |
cbd35700 | 12617 | |
2c78ee89 | 12618 | env->allow_ptr_leaks = bpf_allow_ptr_leaks(); |
01f810ac | 12619 | env->allow_uninit_stack = bpf_allow_uninit_stack(); |
41c48f3a | 12620 | env->allow_ptr_to_map_access = bpf_allow_ptr_to_map_access(); |
2c78ee89 AS |
12621 | env->bypass_spec_v1 = bpf_bypass_spec_v1(); |
12622 | env->bypass_spec_v4 = bpf_bypass_spec_v4(); | |
12623 | env->bpf_capable = bpf_capable(); | |
e2ae4ca2 | 12624 | |
10d274e8 AS |
12625 | if (is_priv) |
12626 | env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ; | |
12627 | ||
cae1927c | 12628 | if (bpf_prog_is_dev_bound(env->prog->aux)) { |
a40a2632 | 12629 | ret = bpf_prog_offload_verifier_prep(env->prog); |
ab3f0063 | 12630 | if (ret) |
f4e3ec0d | 12631 | goto skip_full_check; |
ab3f0063 JK |
12632 | } |
12633 | ||
dc2a4ebc | 12634 | env->explored_states = kvcalloc(state_htab_size(env), |
58e2af8b | 12635 | sizeof(struct bpf_verifier_state_list *), |
f1bca824 AS |
12636 | GFP_USER); |
12637 | ret = -ENOMEM; | |
12638 | if (!env->explored_states) | |
12639 | goto skip_full_check; | |
12640 | ||
d9762e84 | 12641 | ret = check_subprogs(env); |
475fb78f AS |
12642 | if (ret < 0) |
12643 | goto skip_full_check; | |
12644 | ||
c454a46b | 12645 | ret = check_btf_info(env, attr, uattr); |
838e9690 YS |
12646 | if (ret < 0) |
12647 | goto skip_full_check; | |
12648 | ||
be8704ff AS |
12649 | ret = check_attach_btf_id(env); |
12650 | if (ret) | |
12651 | goto skip_full_check; | |
12652 | ||
4976b718 HL |
12653 | ret = resolve_pseudo_ldimm64(env); |
12654 | if (ret < 0) | |
12655 | goto skip_full_check; | |
12656 | ||
d9762e84 MKL |
12657 | ret = check_cfg(env); |
12658 | if (ret < 0) | |
12659 | goto skip_full_check; | |
12660 | ||
51c39bb1 AS |
12661 | ret = do_check_subprogs(env); |
12662 | ret = ret ?: do_check_main(env); | |
cbd35700 | 12663 | |
c941ce9c QM |
12664 | if (ret == 0 && bpf_prog_is_dev_bound(env->prog->aux)) |
12665 | ret = bpf_prog_offload_finalize(env); | |
12666 | ||
0246e64d | 12667 | skip_full_check: |
51c39bb1 | 12668 | kvfree(env->explored_states); |
0246e64d | 12669 | |
c131187d | 12670 | if (ret == 0) |
9b38c405 | 12671 | ret = check_max_stack_depth(env); |
c131187d | 12672 | |
9b38c405 | 12673 | /* instruction rewrites happen after this point */ |
e2ae4ca2 JK |
12674 | if (is_priv) { |
12675 | if (ret == 0) | |
12676 | opt_hard_wire_dead_code_branches(env); | |
52875a04 JK |
12677 | if (ret == 0) |
12678 | ret = opt_remove_dead_code(env); | |
a1b14abc JK |
12679 | if (ret == 0) |
12680 | ret = opt_remove_nops(env); | |
52875a04 JK |
12681 | } else { |
12682 | if (ret == 0) | |
12683 | sanitize_dead_code(env); | |
e2ae4ca2 JK |
12684 | } |
12685 | ||
9bac3d6d AS |
12686 | if (ret == 0) |
12687 | /* program is valid, convert *(u32*)(ctx + off) accesses */ | |
12688 | ret = convert_ctx_accesses(env); | |
12689 | ||
e245c5c6 | 12690 | if (ret == 0) |
79741b3b | 12691 | ret = fixup_bpf_calls(env); |
e245c5c6 | 12692 | |
a4b1d3c1 JW |
12693 | /* do 32-bit optimization after insn patching has done so those patched |
12694 | * insns could be handled correctly. | |
12695 | */ | |
d6c2308c JW |
12696 | if (ret == 0 && !bpf_prog_is_dev_bound(env->prog->aux)) { |
12697 | ret = opt_subreg_zext_lo32_rnd_hi32(env, attr); | |
12698 | env->prog->aux->verifier_zext = bpf_jit_needs_zext() ? !ret | |
12699 | : false; | |
a4b1d3c1 JW |
12700 | } |
12701 | ||
1ea47e01 AS |
12702 | if (ret == 0) |
12703 | ret = fixup_call_args(env); | |
12704 | ||
06ee7115 AS |
12705 | env->verification_time = ktime_get_ns() - start_time; |
12706 | print_verification_stats(env); | |
12707 | ||
a2a7d570 | 12708 | if (log->level && bpf_verifier_log_full(log)) |
cbd35700 | 12709 | ret = -ENOSPC; |
a2a7d570 | 12710 | if (log->level && !log->ubuf) { |
cbd35700 | 12711 | ret = -EFAULT; |
a2a7d570 | 12712 | goto err_release_maps; |
cbd35700 AS |
12713 | } |
12714 | ||
541c3bad AN |
12715 | if (ret) |
12716 | goto err_release_maps; | |
12717 | ||
12718 | if (env->used_map_cnt) { | |
0246e64d | 12719 | /* if program passed verifier, update used_maps in bpf_prog_info */ |
9bac3d6d AS |
12720 | env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt, |
12721 | sizeof(env->used_maps[0]), | |
12722 | GFP_KERNEL); | |
0246e64d | 12723 | |
9bac3d6d | 12724 | if (!env->prog->aux->used_maps) { |
0246e64d | 12725 | ret = -ENOMEM; |
a2a7d570 | 12726 | goto err_release_maps; |
0246e64d AS |
12727 | } |
12728 | ||
9bac3d6d | 12729 | memcpy(env->prog->aux->used_maps, env->used_maps, |
0246e64d | 12730 | sizeof(env->used_maps[0]) * env->used_map_cnt); |
9bac3d6d | 12731 | env->prog->aux->used_map_cnt = env->used_map_cnt; |
541c3bad AN |
12732 | } |
12733 | if (env->used_btf_cnt) { | |
12734 | /* if program passed verifier, update used_btfs in bpf_prog_aux */ | |
12735 | env->prog->aux->used_btfs = kmalloc_array(env->used_btf_cnt, | |
12736 | sizeof(env->used_btfs[0]), | |
12737 | GFP_KERNEL); | |
12738 | if (!env->prog->aux->used_btfs) { | |
12739 | ret = -ENOMEM; | |
12740 | goto err_release_maps; | |
12741 | } | |
0246e64d | 12742 | |
541c3bad AN |
12743 | memcpy(env->prog->aux->used_btfs, env->used_btfs, |
12744 | sizeof(env->used_btfs[0]) * env->used_btf_cnt); | |
12745 | env->prog->aux->used_btf_cnt = env->used_btf_cnt; | |
12746 | } | |
12747 | if (env->used_map_cnt || env->used_btf_cnt) { | |
0246e64d AS |
12748 | /* program is valid. Convert pseudo bpf_ld_imm64 into generic |
12749 | * bpf_ld_imm64 instructions | |
12750 | */ | |
12751 | convert_pseudo_ld_imm64(env); | |
12752 | } | |
cbd35700 | 12753 | |
541c3bad | 12754 | adjust_btf_func(env); |
ba64e7d8 | 12755 | |
a2a7d570 | 12756 | err_release_maps: |
9bac3d6d | 12757 | if (!env->prog->aux->used_maps) |
0246e64d | 12758 | /* if we didn't copy map pointers into bpf_prog_info, release |
ab7f5bf0 | 12759 | * them now. Otherwise free_used_maps() will release them. |
0246e64d AS |
12760 | */ |
12761 | release_maps(env); | |
541c3bad AN |
12762 | if (!env->prog->aux->used_btfs) |
12763 | release_btfs(env); | |
03f87c0b THJ |
12764 | |
12765 | /* extension progs temporarily inherit the attach_type of their targets | |
12766 | for verification purposes, so set it back to zero before returning | |
12767 | */ | |
12768 | if (env->prog->type == BPF_PROG_TYPE_EXT) | |
12769 | env->prog->expected_attach_type = 0; | |
12770 | ||
9bac3d6d | 12771 | *prog = env->prog; |
3df126f3 | 12772 | err_unlock: |
45a73c17 AS |
12773 | if (!is_priv) |
12774 | mutex_unlock(&bpf_verifier_lock); | |
3df126f3 JK |
12775 | vfree(env->insn_aux_data); |
12776 | err_free_env: | |
12777 | kfree(env); | |
51580e79 AS |
12778 | return ret; |
12779 | } |