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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> |
51580e79 | 22 | |
f4ac7e0b JK |
23 | #include "disasm.h" |
24 | ||
00176a34 JK |
25 | static const struct bpf_verifier_ops * const bpf_verifier_ops[] = { |
26 | #define BPF_PROG_TYPE(_id, _name) \ | |
27 | [_id] = & _name ## _verifier_ops, | |
28 | #define BPF_MAP_TYPE(_id, _ops) | |
29 | #include <linux/bpf_types.h> | |
30 | #undef BPF_PROG_TYPE | |
31 | #undef BPF_MAP_TYPE | |
32 | }; | |
33 | ||
51580e79 AS |
34 | /* bpf_check() is a static code analyzer that walks eBPF program |
35 | * instruction by instruction and updates register/stack state. | |
36 | * All paths of conditional branches are analyzed until 'bpf_exit' insn. | |
37 | * | |
38 | * The first pass is depth-first-search to check that the program is a DAG. | |
39 | * It rejects the following programs: | |
40 | * - larger than BPF_MAXINSNS insns | |
41 | * - if loop is present (detected via back-edge) | |
42 | * - unreachable insns exist (shouldn't be a forest. program = one function) | |
43 | * - out of bounds or malformed jumps | |
44 | * The second pass is all possible path descent from the 1st insn. | |
45 | * Since it's analyzing all pathes through the program, the length of the | |
eba38a96 | 46 | * analysis is limited to 64k insn, which may be hit even if total number of |
51580e79 AS |
47 | * insn is less then 4K, but there are too many branches that change stack/regs. |
48 | * Number of 'branches to be analyzed' is limited to 1k | |
49 | * | |
50 | * On entry to each instruction, each register has a type, and the instruction | |
51 | * changes the types of the registers depending on instruction semantics. | |
52 | * If instruction is BPF_MOV64_REG(BPF_REG_1, BPF_REG_5), then type of R5 is | |
53 | * copied to R1. | |
54 | * | |
55 | * All registers are 64-bit. | |
56 | * R0 - return register | |
57 | * R1-R5 argument passing registers | |
58 | * R6-R9 callee saved registers | |
59 | * R10 - frame pointer read-only | |
60 | * | |
61 | * At the start of BPF program the register R1 contains a pointer to bpf_context | |
62 | * and has type PTR_TO_CTX. | |
63 | * | |
64 | * Verifier tracks arithmetic operations on pointers in case: | |
65 | * BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), | |
66 | * BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -20), | |
67 | * 1st insn copies R10 (which has FRAME_PTR) type into R1 | |
68 | * and 2nd arithmetic instruction is pattern matched to recognize | |
69 | * that it wants to construct a pointer to some element within stack. | |
70 | * So after 2nd insn, the register R1 has type PTR_TO_STACK | |
71 | * (and -20 constant is saved for further stack bounds checking). | |
72 | * Meaning that this reg is a pointer to stack plus known immediate constant. | |
73 | * | |
f1174f77 | 74 | * Most of the time the registers have SCALAR_VALUE type, which |
51580e79 | 75 | * means the register has some value, but it's not a valid pointer. |
f1174f77 | 76 | * (like pointer plus pointer becomes SCALAR_VALUE type) |
51580e79 AS |
77 | * |
78 | * When verifier sees load or store instructions the type of base register | |
c64b7983 JS |
79 | * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK, PTR_TO_SOCKET. These are |
80 | * four pointer types recognized by check_mem_access() function. | |
51580e79 AS |
81 | * |
82 | * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value' | |
83 | * and the range of [ptr, ptr + map's value_size) is accessible. | |
84 | * | |
85 | * registers used to pass values to function calls are checked against | |
86 | * function argument constraints. | |
87 | * | |
88 | * ARG_PTR_TO_MAP_KEY is one of such argument constraints. | |
89 | * It means that the register type passed to this function must be | |
90 | * PTR_TO_STACK and it will be used inside the function as | |
91 | * 'pointer to map element key' | |
92 | * | |
93 | * For example the argument constraints for bpf_map_lookup_elem(): | |
94 | * .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, | |
95 | * .arg1_type = ARG_CONST_MAP_PTR, | |
96 | * .arg2_type = ARG_PTR_TO_MAP_KEY, | |
97 | * | |
98 | * ret_type says that this function returns 'pointer to map elem value or null' | |
99 | * function expects 1st argument to be a const pointer to 'struct bpf_map' and | |
100 | * 2nd argument should be a pointer to stack, which will be used inside | |
101 | * the helper function as a pointer to map element key. | |
102 | * | |
103 | * On the kernel side the helper function looks like: | |
104 | * u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) | |
105 | * { | |
106 | * struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; | |
107 | * void *key = (void *) (unsigned long) r2; | |
108 | * void *value; | |
109 | * | |
110 | * here kernel can access 'key' and 'map' pointers safely, knowing that | |
111 | * [key, key + map->key_size) bytes are valid and were initialized on | |
112 | * the stack of eBPF program. | |
113 | * } | |
114 | * | |
115 | * Corresponding eBPF program may look like: | |
116 | * BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), // after this insn R2 type is FRAME_PTR | |
117 | * BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), // after this insn R2 type is PTR_TO_STACK | |
118 | * BPF_LD_MAP_FD(BPF_REG_1, map_fd), // after this insn R1 type is CONST_PTR_TO_MAP | |
119 | * BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), | |
120 | * here verifier looks at prototype of map_lookup_elem() and sees: | |
121 | * .arg1_type == ARG_CONST_MAP_PTR and R1->type == CONST_PTR_TO_MAP, which is ok, | |
122 | * Now verifier knows that this map has key of R1->map_ptr->key_size bytes | |
123 | * | |
124 | * Then .arg2_type == ARG_PTR_TO_MAP_KEY and R2->type == PTR_TO_STACK, ok so far, | |
125 | * Now verifier checks that [R2, R2 + map's key_size) are within stack limits | |
126 | * and were initialized prior to this call. | |
127 | * If it's ok, then verifier allows this BPF_CALL insn and looks at | |
128 | * .ret_type which is RET_PTR_TO_MAP_VALUE_OR_NULL, so it sets | |
129 | * R0->type = PTR_TO_MAP_VALUE_OR_NULL which means bpf_map_lookup_elem() function | |
130 | * returns ether pointer to map value or NULL. | |
131 | * | |
132 | * When type PTR_TO_MAP_VALUE_OR_NULL passes through 'if (reg != 0) goto +off' | |
133 | * insn, the register holding that pointer in the true branch changes state to | |
134 | * PTR_TO_MAP_VALUE and the same register changes state to CONST_IMM in the false | |
135 | * branch. See check_cond_jmp_op(). | |
136 | * | |
137 | * After the call R0 is set to return type of the function and registers R1-R5 | |
138 | * are set to NOT_INIT to indicate that they are no longer readable. | |
fd978bf7 JS |
139 | * |
140 | * The following reference types represent a potential reference to a kernel | |
141 | * resource which, after first being allocated, must be checked and freed by | |
142 | * the BPF program: | |
143 | * - PTR_TO_SOCKET_OR_NULL, PTR_TO_SOCKET | |
144 | * | |
145 | * When the verifier sees a helper call return a reference type, it allocates a | |
146 | * pointer id for the reference and stores it in the current function state. | |
147 | * Similar to the way that PTR_TO_MAP_VALUE_OR_NULL is converted into | |
148 | * PTR_TO_MAP_VALUE, PTR_TO_SOCKET_OR_NULL becomes PTR_TO_SOCKET when the type | |
149 | * passes through a NULL-check conditional. For the branch wherein the state is | |
150 | * changed to CONST_IMM, the verifier releases the reference. | |
6acc9b43 JS |
151 | * |
152 | * For each helper function that allocates a reference, such as | |
153 | * bpf_sk_lookup_tcp(), there is a corresponding release function, such as | |
154 | * bpf_sk_release(). When a reference type passes into the release function, | |
155 | * the verifier also releases the reference. If any unchecked or unreleased | |
156 | * reference remains at the end of the program, the verifier rejects it. | |
51580e79 AS |
157 | */ |
158 | ||
17a52670 | 159 | /* verifier_state + insn_idx are pushed to stack when branch is encountered */ |
58e2af8b | 160 | struct bpf_verifier_stack_elem { |
17a52670 AS |
161 | /* verifer state is 'st' |
162 | * before processing instruction 'insn_idx' | |
163 | * and after processing instruction 'prev_insn_idx' | |
164 | */ | |
58e2af8b | 165 | struct bpf_verifier_state st; |
17a52670 AS |
166 | int insn_idx; |
167 | int prev_insn_idx; | |
58e2af8b | 168 | struct bpf_verifier_stack_elem *next; |
cbd35700 AS |
169 | }; |
170 | ||
b285fcb7 | 171 | #define BPF_COMPLEXITY_LIMIT_JMP_SEQ 8192 |
ceefbc96 | 172 | #define BPF_COMPLEXITY_LIMIT_STATES 64 |
07016151 | 173 | |
c93552c4 DB |
174 | #define BPF_MAP_PTR_UNPRIV 1UL |
175 | #define BPF_MAP_PTR_POISON ((void *)((0xeB9FUL << 1) + \ | |
176 | POISON_POINTER_DELTA)) | |
177 | #define BPF_MAP_PTR(X) ((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV)) | |
178 | ||
179 | static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux) | |
180 | { | |
181 | return BPF_MAP_PTR(aux->map_state) == BPF_MAP_PTR_POISON; | |
182 | } | |
183 | ||
184 | static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data *aux) | |
185 | { | |
186 | return aux->map_state & BPF_MAP_PTR_UNPRIV; | |
187 | } | |
188 | ||
189 | static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux, | |
190 | const struct bpf_map *map, bool unpriv) | |
191 | { | |
192 | BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON & BPF_MAP_PTR_UNPRIV); | |
193 | unpriv |= bpf_map_ptr_unpriv(aux); | |
194 | aux->map_state = (unsigned long)map | | |
195 | (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL); | |
196 | } | |
fad73a1a | 197 | |
33ff9823 DB |
198 | struct bpf_call_arg_meta { |
199 | struct bpf_map *map_ptr; | |
435faee1 | 200 | bool raw_mode; |
36bbef52 | 201 | bool pkt_access; |
435faee1 DB |
202 | int regno; |
203 | int access_size; | |
849fa506 YS |
204 | s64 msize_smax_value; |
205 | u64 msize_umax_value; | |
1b986589 | 206 | int ref_obj_id; |
d83525ca | 207 | int func_id; |
a7658e1a | 208 | u32 btf_id; |
33ff9823 DB |
209 | }; |
210 | ||
8580ac94 AS |
211 | struct btf *btf_vmlinux; |
212 | ||
cbd35700 AS |
213 | static DEFINE_MUTEX(bpf_verifier_lock); |
214 | ||
d9762e84 MKL |
215 | static const struct bpf_line_info * |
216 | find_linfo(const struct bpf_verifier_env *env, u32 insn_off) | |
217 | { | |
218 | const struct bpf_line_info *linfo; | |
219 | const struct bpf_prog *prog; | |
220 | u32 i, nr_linfo; | |
221 | ||
222 | prog = env->prog; | |
223 | nr_linfo = prog->aux->nr_linfo; | |
224 | ||
225 | if (!nr_linfo || insn_off >= prog->len) | |
226 | return NULL; | |
227 | ||
228 | linfo = prog->aux->linfo; | |
229 | for (i = 1; i < nr_linfo; i++) | |
230 | if (insn_off < linfo[i].insn_off) | |
231 | break; | |
232 | ||
233 | return &linfo[i - 1]; | |
234 | } | |
235 | ||
77d2e05a MKL |
236 | void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt, |
237 | va_list args) | |
cbd35700 | 238 | { |
a2a7d570 | 239 | unsigned int n; |
cbd35700 | 240 | |
a2a7d570 | 241 | n = vscnprintf(log->kbuf, BPF_VERIFIER_TMP_LOG_SIZE, fmt, args); |
a2a7d570 JK |
242 | |
243 | WARN_ONCE(n >= BPF_VERIFIER_TMP_LOG_SIZE - 1, | |
244 | "verifier log line truncated - local buffer too short\n"); | |
245 | ||
246 | n = min(log->len_total - log->len_used - 1, n); | |
247 | log->kbuf[n] = '\0'; | |
248 | ||
8580ac94 AS |
249 | if (log->level == BPF_LOG_KERNEL) { |
250 | pr_err("BPF:%s\n", log->kbuf); | |
251 | return; | |
252 | } | |
a2a7d570 JK |
253 | if (!copy_to_user(log->ubuf + log->len_used, log->kbuf, n + 1)) |
254 | log->len_used += n; | |
255 | else | |
256 | log->ubuf = NULL; | |
cbd35700 | 257 | } |
abe08840 JO |
258 | |
259 | /* log_level controls verbosity level of eBPF verifier. | |
260 | * bpf_verifier_log_write() is used to dump the verification trace to the log, | |
261 | * so the user can figure out what's wrong with the program | |
430e68d1 | 262 | */ |
abe08840 JO |
263 | __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env, |
264 | const char *fmt, ...) | |
265 | { | |
266 | va_list args; | |
267 | ||
77d2e05a MKL |
268 | if (!bpf_verifier_log_needed(&env->log)) |
269 | return; | |
270 | ||
abe08840 | 271 | va_start(args, fmt); |
77d2e05a | 272 | bpf_verifier_vlog(&env->log, fmt, args); |
abe08840 JO |
273 | va_end(args); |
274 | } | |
275 | EXPORT_SYMBOL_GPL(bpf_verifier_log_write); | |
276 | ||
277 | __printf(2, 3) static void verbose(void *private_data, const char *fmt, ...) | |
278 | { | |
77d2e05a | 279 | struct bpf_verifier_env *env = private_data; |
abe08840 JO |
280 | va_list args; |
281 | ||
77d2e05a MKL |
282 | if (!bpf_verifier_log_needed(&env->log)) |
283 | return; | |
284 | ||
abe08840 | 285 | va_start(args, fmt); |
77d2e05a | 286 | bpf_verifier_vlog(&env->log, fmt, args); |
abe08840 JO |
287 | va_end(args); |
288 | } | |
cbd35700 | 289 | |
9e15db66 AS |
290 | __printf(2, 3) void bpf_log(struct bpf_verifier_log *log, |
291 | const char *fmt, ...) | |
292 | { | |
293 | va_list args; | |
294 | ||
295 | if (!bpf_verifier_log_needed(log)) | |
296 | return; | |
297 | ||
298 | va_start(args, fmt); | |
299 | bpf_verifier_vlog(log, fmt, args); | |
300 | va_end(args); | |
301 | } | |
302 | ||
d9762e84 MKL |
303 | static const char *ltrim(const char *s) |
304 | { | |
305 | while (isspace(*s)) | |
306 | s++; | |
307 | ||
308 | return s; | |
309 | } | |
310 | ||
311 | __printf(3, 4) static void verbose_linfo(struct bpf_verifier_env *env, | |
312 | u32 insn_off, | |
313 | const char *prefix_fmt, ...) | |
314 | { | |
315 | const struct bpf_line_info *linfo; | |
316 | ||
317 | if (!bpf_verifier_log_needed(&env->log)) | |
318 | return; | |
319 | ||
320 | linfo = find_linfo(env, insn_off); | |
321 | if (!linfo || linfo == env->prev_linfo) | |
322 | return; | |
323 | ||
324 | if (prefix_fmt) { | |
325 | va_list args; | |
326 | ||
327 | va_start(args, prefix_fmt); | |
328 | bpf_verifier_vlog(&env->log, prefix_fmt, args); | |
329 | va_end(args); | |
330 | } | |
331 | ||
332 | verbose(env, "%s\n", | |
333 | ltrim(btf_name_by_offset(env->prog->aux->btf, | |
334 | linfo->line_off))); | |
335 | ||
336 | env->prev_linfo = linfo; | |
337 | } | |
338 | ||
de8f3a83 DB |
339 | static bool type_is_pkt_pointer(enum bpf_reg_type type) |
340 | { | |
341 | return type == PTR_TO_PACKET || | |
342 | type == PTR_TO_PACKET_META; | |
343 | } | |
344 | ||
46f8bc92 MKL |
345 | static bool type_is_sk_pointer(enum bpf_reg_type type) |
346 | { | |
347 | return type == PTR_TO_SOCKET || | |
655a51e5 | 348 | type == PTR_TO_SOCK_COMMON || |
fada7fdc JL |
349 | type == PTR_TO_TCP_SOCK || |
350 | type == PTR_TO_XDP_SOCK; | |
46f8bc92 MKL |
351 | } |
352 | ||
840b9615 JS |
353 | static bool reg_type_may_be_null(enum bpf_reg_type type) |
354 | { | |
fd978bf7 | 355 | return type == PTR_TO_MAP_VALUE_OR_NULL || |
46f8bc92 | 356 | type == PTR_TO_SOCKET_OR_NULL || |
655a51e5 MKL |
357 | type == PTR_TO_SOCK_COMMON_OR_NULL || |
358 | type == PTR_TO_TCP_SOCK_OR_NULL; | |
fd978bf7 JS |
359 | } |
360 | ||
d83525ca AS |
361 | static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg) |
362 | { | |
363 | return reg->type == PTR_TO_MAP_VALUE && | |
364 | map_value_has_spin_lock(reg->map_ptr); | |
365 | } | |
366 | ||
cba368c1 MKL |
367 | static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type) |
368 | { | |
369 | return type == PTR_TO_SOCKET || | |
370 | type == PTR_TO_SOCKET_OR_NULL || | |
371 | type == PTR_TO_TCP_SOCK || | |
372 | type == PTR_TO_TCP_SOCK_OR_NULL; | |
373 | } | |
374 | ||
1b986589 | 375 | static bool arg_type_may_be_refcounted(enum bpf_arg_type type) |
fd978bf7 | 376 | { |
1b986589 | 377 | return type == ARG_PTR_TO_SOCK_COMMON; |
fd978bf7 JS |
378 | } |
379 | ||
380 | /* Determine whether the function releases some resources allocated by another | |
381 | * function call. The first reference type argument will be assumed to be | |
382 | * released by release_reference(). | |
383 | */ | |
384 | static bool is_release_function(enum bpf_func_id func_id) | |
385 | { | |
6acc9b43 | 386 | return func_id == BPF_FUNC_sk_release; |
840b9615 JS |
387 | } |
388 | ||
46f8bc92 MKL |
389 | static bool is_acquire_function(enum bpf_func_id func_id) |
390 | { | |
391 | return func_id == BPF_FUNC_sk_lookup_tcp || | |
edbf8c01 LB |
392 | func_id == BPF_FUNC_sk_lookup_udp || |
393 | func_id == BPF_FUNC_skc_lookup_tcp; | |
46f8bc92 MKL |
394 | } |
395 | ||
1b986589 MKL |
396 | static bool is_ptr_cast_function(enum bpf_func_id func_id) |
397 | { | |
398 | return func_id == BPF_FUNC_tcp_sock || | |
399 | func_id == BPF_FUNC_sk_fullsock; | |
400 | } | |
401 | ||
17a52670 AS |
402 | /* string representation of 'enum bpf_reg_type' */ |
403 | static const char * const reg_type_str[] = { | |
404 | [NOT_INIT] = "?", | |
f1174f77 | 405 | [SCALAR_VALUE] = "inv", |
17a52670 AS |
406 | [PTR_TO_CTX] = "ctx", |
407 | [CONST_PTR_TO_MAP] = "map_ptr", | |
408 | [PTR_TO_MAP_VALUE] = "map_value", | |
409 | [PTR_TO_MAP_VALUE_OR_NULL] = "map_value_or_null", | |
17a52670 | 410 | [PTR_TO_STACK] = "fp", |
969bf05e | 411 | [PTR_TO_PACKET] = "pkt", |
de8f3a83 | 412 | [PTR_TO_PACKET_META] = "pkt_meta", |
969bf05e | 413 | [PTR_TO_PACKET_END] = "pkt_end", |
d58e468b | 414 | [PTR_TO_FLOW_KEYS] = "flow_keys", |
c64b7983 JS |
415 | [PTR_TO_SOCKET] = "sock", |
416 | [PTR_TO_SOCKET_OR_NULL] = "sock_or_null", | |
46f8bc92 MKL |
417 | [PTR_TO_SOCK_COMMON] = "sock_common", |
418 | [PTR_TO_SOCK_COMMON_OR_NULL] = "sock_common_or_null", | |
655a51e5 MKL |
419 | [PTR_TO_TCP_SOCK] = "tcp_sock", |
420 | [PTR_TO_TCP_SOCK_OR_NULL] = "tcp_sock_or_null", | |
9df1c28b | 421 | [PTR_TO_TP_BUFFER] = "tp_buffer", |
fada7fdc | 422 | [PTR_TO_XDP_SOCK] = "xdp_sock", |
9e15db66 | 423 | [PTR_TO_BTF_ID] = "ptr_", |
17a52670 AS |
424 | }; |
425 | ||
8efea21d EC |
426 | static char slot_type_char[] = { |
427 | [STACK_INVALID] = '?', | |
428 | [STACK_SPILL] = 'r', | |
429 | [STACK_MISC] = 'm', | |
430 | [STACK_ZERO] = '0', | |
431 | }; | |
432 | ||
4e92024a AS |
433 | static void print_liveness(struct bpf_verifier_env *env, |
434 | enum bpf_reg_liveness live) | |
435 | { | |
9242b5f5 | 436 | if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN | REG_LIVE_DONE)) |
4e92024a AS |
437 | verbose(env, "_"); |
438 | if (live & REG_LIVE_READ) | |
439 | verbose(env, "r"); | |
440 | if (live & REG_LIVE_WRITTEN) | |
441 | verbose(env, "w"); | |
9242b5f5 AS |
442 | if (live & REG_LIVE_DONE) |
443 | verbose(env, "D"); | |
4e92024a AS |
444 | } |
445 | ||
f4d7e40a AS |
446 | static struct bpf_func_state *func(struct bpf_verifier_env *env, |
447 | const struct bpf_reg_state *reg) | |
448 | { | |
449 | struct bpf_verifier_state *cur = env->cur_state; | |
450 | ||
451 | return cur->frame[reg->frameno]; | |
452 | } | |
453 | ||
9e15db66 AS |
454 | const char *kernel_type_name(u32 id) |
455 | { | |
456 | return btf_name_by_offset(btf_vmlinux, | |
457 | btf_type_by_id(btf_vmlinux, id)->name_off); | |
458 | } | |
459 | ||
61bd5218 | 460 | static void print_verifier_state(struct bpf_verifier_env *env, |
f4d7e40a | 461 | const struct bpf_func_state *state) |
17a52670 | 462 | { |
f4d7e40a | 463 | const struct bpf_reg_state *reg; |
17a52670 AS |
464 | enum bpf_reg_type t; |
465 | int i; | |
466 | ||
f4d7e40a AS |
467 | if (state->frameno) |
468 | verbose(env, " frame%d:", state->frameno); | |
17a52670 | 469 | for (i = 0; i < MAX_BPF_REG; i++) { |
1a0dc1ac AS |
470 | reg = &state->regs[i]; |
471 | t = reg->type; | |
17a52670 AS |
472 | if (t == NOT_INIT) |
473 | continue; | |
4e92024a AS |
474 | verbose(env, " R%d", i); |
475 | print_liveness(env, reg->live); | |
476 | verbose(env, "=%s", reg_type_str[t]); | |
b5dc0163 AS |
477 | if (t == SCALAR_VALUE && reg->precise) |
478 | verbose(env, "P"); | |
f1174f77 EC |
479 | if ((t == SCALAR_VALUE || t == PTR_TO_STACK) && |
480 | tnum_is_const(reg->var_off)) { | |
481 | /* reg->off should be 0 for SCALAR_VALUE */ | |
61bd5218 | 482 | verbose(env, "%lld", reg->var_off.value + reg->off); |
f1174f77 | 483 | } else { |
9e15db66 AS |
484 | if (t == PTR_TO_BTF_ID) |
485 | verbose(env, "%s", kernel_type_name(reg->btf_id)); | |
cba368c1 MKL |
486 | verbose(env, "(id=%d", reg->id); |
487 | if (reg_type_may_be_refcounted_or_null(t)) | |
488 | verbose(env, ",ref_obj_id=%d", reg->ref_obj_id); | |
f1174f77 | 489 | if (t != SCALAR_VALUE) |
61bd5218 | 490 | verbose(env, ",off=%d", reg->off); |
de8f3a83 | 491 | if (type_is_pkt_pointer(t)) |
61bd5218 | 492 | verbose(env, ",r=%d", reg->range); |
f1174f77 EC |
493 | else if (t == CONST_PTR_TO_MAP || |
494 | t == PTR_TO_MAP_VALUE || | |
495 | t == PTR_TO_MAP_VALUE_OR_NULL) | |
61bd5218 | 496 | verbose(env, ",ks=%d,vs=%d", |
f1174f77 EC |
497 | reg->map_ptr->key_size, |
498 | reg->map_ptr->value_size); | |
7d1238f2 EC |
499 | if (tnum_is_const(reg->var_off)) { |
500 | /* Typically an immediate SCALAR_VALUE, but | |
501 | * could be a pointer whose offset is too big | |
502 | * for reg->off | |
503 | */ | |
61bd5218 | 504 | verbose(env, ",imm=%llx", reg->var_off.value); |
7d1238f2 EC |
505 | } else { |
506 | if (reg->smin_value != reg->umin_value && | |
507 | reg->smin_value != S64_MIN) | |
61bd5218 | 508 | verbose(env, ",smin_value=%lld", |
7d1238f2 EC |
509 | (long long)reg->smin_value); |
510 | if (reg->smax_value != reg->umax_value && | |
511 | reg->smax_value != S64_MAX) | |
61bd5218 | 512 | verbose(env, ",smax_value=%lld", |
7d1238f2 EC |
513 | (long long)reg->smax_value); |
514 | if (reg->umin_value != 0) | |
61bd5218 | 515 | verbose(env, ",umin_value=%llu", |
7d1238f2 EC |
516 | (unsigned long long)reg->umin_value); |
517 | if (reg->umax_value != U64_MAX) | |
61bd5218 | 518 | verbose(env, ",umax_value=%llu", |
7d1238f2 EC |
519 | (unsigned long long)reg->umax_value); |
520 | if (!tnum_is_unknown(reg->var_off)) { | |
521 | char tn_buf[48]; | |
f1174f77 | 522 | |
7d1238f2 | 523 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); |
61bd5218 | 524 | verbose(env, ",var_off=%s", tn_buf); |
7d1238f2 | 525 | } |
f1174f77 | 526 | } |
61bd5218 | 527 | verbose(env, ")"); |
f1174f77 | 528 | } |
17a52670 | 529 | } |
638f5b90 | 530 | for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) { |
8efea21d EC |
531 | char types_buf[BPF_REG_SIZE + 1]; |
532 | bool valid = false; | |
533 | int j; | |
534 | ||
535 | for (j = 0; j < BPF_REG_SIZE; j++) { | |
536 | if (state->stack[i].slot_type[j] != STACK_INVALID) | |
537 | valid = true; | |
538 | types_buf[j] = slot_type_char[ | |
539 | state->stack[i].slot_type[j]]; | |
540 | } | |
541 | types_buf[BPF_REG_SIZE] = 0; | |
542 | if (!valid) | |
543 | continue; | |
544 | verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE); | |
545 | print_liveness(env, state->stack[i].spilled_ptr.live); | |
b5dc0163 AS |
546 | if (state->stack[i].slot_type[0] == STACK_SPILL) { |
547 | reg = &state->stack[i].spilled_ptr; | |
548 | t = reg->type; | |
549 | verbose(env, "=%s", reg_type_str[t]); | |
550 | if (t == SCALAR_VALUE && reg->precise) | |
551 | verbose(env, "P"); | |
552 | if (t == SCALAR_VALUE && tnum_is_const(reg->var_off)) | |
553 | verbose(env, "%lld", reg->var_off.value + reg->off); | |
554 | } else { | |
8efea21d | 555 | verbose(env, "=%s", types_buf); |
b5dc0163 | 556 | } |
17a52670 | 557 | } |
fd978bf7 JS |
558 | if (state->acquired_refs && state->refs[0].id) { |
559 | verbose(env, " refs=%d", state->refs[0].id); | |
560 | for (i = 1; i < state->acquired_refs; i++) | |
561 | if (state->refs[i].id) | |
562 | verbose(env, ",%d", state->refs[i].id); | |
563 | } | |
61bd5218 | 564 | verbose(env, "\n"); |
17a52670 AS |
565 | } |
566 | ||
84dbf350 JS |
567 | #define COPY_STATE_FN(NAME, COUNT, FIELD, SIZE) \ |
568 | static int copy_##NAME##_state(struct bpf_func_state *dst, \ | |
569 | const struct bpf_func_state *src) \ | |
570 | { \ | |
571 | if (!src->FIELD) \ | |
572 | return 0; \ | |
573 | if (WARN_ON_ONCE(dst->COUNT < src->COUNT)) { \ | |
574 | /* internal bug, make state invalid to reject the program */ \ | |
575 | memset(dst, 0, sizeof(*dst)); \ | |
576 | return -EFAULT; \ | |
577 | } \ | |
578 | memcpy(dst->FIELD, src->FIELD, \ | |
579 | sizeof(*src->FIELD) * (src->COUNT / SIZE)); \ | |
580 | return 0; \ | |
638f5b90 | 581 | } |
fd978bf7 JS |
582 | /* copy_reference_state() */ |
583 | COPY_STATE_FN(reference, acquired_refs, refs, 1) | |
84dbf350 JS |
584 | /* copy_stack_state() */ |
585 | COPY_STATE_FN(stack, allocated_stack, stack, BPF_REG_SIZE) | |
586 | #undef COPY_STATE_FN | |
587 | ||
588 | #define REALLOC_STATE_FN(NAME, COUNT, FIELD, SIZE) \ | |
589 | static int realloc_##NAME##_state(struct bpf_func_state *state, int size, \ | |
590 | bool copy_old) \ | |
591 | { \ | |
592 | u32 old_size = state->COUNT; \ | |
593 | struct bpf_##NAME##_state *new_##FIELD; \ | |
594 | int slot = size / SIZE; \ | |
595 | \ | |
596 | if (size <= old_size || !size) { \ | |
597 | if (copy_old) \ | |
598 | return 0; \ | |
599 | state->COUNT = slot * SIZE; \ | |
600 | if (!size && old_size) { \ | |
601 | kfree(state->FIELD); \ | |
602 | state->FIELD = NULL; \ | |
603 | } \ | |
604 | return 0; \ | |
605 | } \ | |
606 | new_##FIELD = kmalloc_array(slot, sizeof(struct bpf_##NAME##_state), \ | |
607 | GFP_KERNEL); \ | |
608 | if (!new_##FIELD) \ | |
609 | return -ENOMEM; \ | |
610 | if (copy_old) { \ | |
611 | if (state->FIELD) \ | |
612 | memcpy(new_##FIELD, state->FIELD, \ | |
613 | sizeof(*new_##FIELD) * (old_size / SIZE)); \ | |
614 | memset(new_##FIELD + old_size / SIZE, 0, \ | |
615 | sizeof(*new_##FIELD) * (size - old_size) / SIZE); \ | |
616 | } \ | |
617 | state->COUNT = slot * SIZE; \ | |
618 | kfree(state->FIELD); \ | |
619 | state->FIELD = new_##FIELD; \ | |
620 | return 0; \ | |
621 | } | |
fd978bf7 JS |
622 | /* realloc_reference_state() */ |
623 | REALLOC_STATE_FN(reference, acquired_refs, refs, 1) | |
84dbf350 JS |
624 | /* realloc_stack_state() */ |
625 | REALLOC_STATE_FN(stack, allocated_stack, stack, BPF_REG_SIZE) | |
626 | #undef REALLOC_STATE_FN | |
638f5b90 AS |
627 | |
628 | /* do_check() starts with zero-sized stack in struct bpf_verifier_state to | |
629 | * make it consume minimal amount of memory. check_stack_write() access from | |
f4d7e40a | 630 | * the program calls into realloc_func_state() to grow the stack size. |
84dbf350 JS |
631 | * Note there is a non-zero 'parent' pointer inside bpf_verifier_state |
632 | * which realloc_stack_state() copies over. It points to previous | |
633 | * bpf_verifier_state which is never reallocated. | |
638f5b90 | 634 | */ |
fd978bf7 JS |
635 | static int realloc_func_state(struct bpf_func_state *state, int stack_size, |
636 | int refs_size, bool copy_old) | |
638f5b90 | 637 | { |
fd978bf7 JS |
638 | int err = realloc_reference_state(state, refs_size, copy_old); |
639 | if (err) | |
640 | return err; | |
641 | return realloc_stack_state(state, stack_size, copy_old); | |
642 | } | |
643 | ||
644 | /* Acquire a pointer id from the env and update the state->refs to include | |
645 | * this new pointer reference. | |
646 | * On success, returns a valid pointer id to associate with the register | |
647 | * On failure, returns a negative errno. | |
638f5b90 | 648 | */ |
fd978bf7 | 649 | static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx) |
638f5b90 | 650 | { |
fd978bf7 JS |
651 | struct bpf_func_state *state = cur_func(env); |
652 | int new_ofs = state->acquired_refs; | |
653 | int id, err; | |
654 | ||
655 | err = realloc_reference_state(state, state->acquired_refs + 1, true); | |
656 | if (err) | |
657 | return err; | |
658 | id = ++env->id_gen; | |
659 | state->refs[new_ofs].id = id; | |
660 | state->refs[new_ofs].insn_idx = insn_idx; | |
638f5b90 | 661 | |
fd978bf7 JS |
662 | return id; |
663 | } | |
664 | ||
665 | /* release function corresponding to acquire_reference_state(). Idempotent. */ | |
46f8bc92 | 666 | static int release_reference_state(struct bpf_func_state *state, int ptr_id) |
fd978bf7 JS |
667 | { |
668 | int i, last_idx; | |
669 | ||
fd978bf7 JS |
670 | last_idx = state->acquired_refs - 1; |
671 | for (i = 0; i < state->acquired_refs; i++) { | |
672 | if (state->refs[i].id == ptr_id) { | |
673 | if (last_idx && i != last_idx) | |
674 | memcpy(&state->refs[i], &state->refs[last_idx], | |
675 | sizeof(*state->refs)); | |
676 | memset(&state->refs[last_idx], 0, sizeof(*state->refs)); | |
677 | state->acquired_refs--; | |
638f5b90 | 678 | return 0; |
638f5b90 | 679 | } |
638f5b90 | 680 | } |
46f8bc92 | 681 | return -EINVAL; |
fd978bf7 JS |
682 | } |
683 | ||
684 | static int transfer_reference_state(struct bpf_func_state *dst, | |
685 | struct bpf_func_state *src) | |
686 | { | |
687 | int err = realloc_reference_state(dst, src->acquired_refs, false); | |
688 | if (err) | |
689 | return err; | |
690 | err = copy_reference_state(dst, src); | |
691 | if (err) | |
692 | return err; | |
638f5b90 AS |
693 | return 0; |
694 | } | |
695 | ||
f4d7e40a AS |
696 | static void free_func_state(struct bpf_func_state *state) |
697 | { | |
5896351e AS |
698 | if (!state) |
699 | return; | |
fd978bf7 | 700 | kfree(state->refs); |
f4d7e40a AS |
701 | kfree(state->stack); |
702 | kfree(state); | |
703 | } | |
704 | ||
b5dc0163 AS |
705 | static void clear_jmp_history(struct bpf_verifier_state *state) |
706 | { | |
707 | kfree(state->jmp_history); | |
708 | state->jmp_history = NULL; | |
709 | state->jmp_history_cnt = 0; | |
710 | } | |
711 | ||
1969db47 AS |
712 | static void free_verifier_state(struct bpf_verifier_state *state, |
713 | bool free_self) | |
638f5b90 | 714 | { |
f4d7e40a AS |
715 | int i; |
716 | ||
717 | for (i = 0; i <= state->curframe; i++) { | |
718 | free_func_state(state->frame[i]); | |
719 | state->frame[i] = NULL; | |
720 | } | |
b5dc0163 | 721 | clear_jmp_history(state); |
1969db47 AS |
722 | if (free_self) |
723 | kfree(state); | |
638f5b90 AS |
724 | } |
725 | ||
726 | /* copy verifier state from src to dst growing dst stack space | |
727 | * when necessary to accommodate larger src stack | |
728 | */ | |
f4d7e40a AS |
729 | static int copy_func_state(struct bpf_func_state *dst, |
730 | const struct bpf_func_state *src) | |
638f5b90 AS |
731 | { |
732 | int err; | |
733 | ||
fd978bf7 JS |
734 | err = realloc_func_state(dst, src->allocated_stack, src->acquired_refs, |
735 | false); | |
736 | if (err) | |
737 | return err; | |
738 | memcpy(dst, src, offsetof(struct bpf_func_state, acquired_refs)); | |
739 | err = copy_reference_state(dst, src); | |
638f5b90 AS |
740 | if (err) |
741 | return err; | |
638f5b90 AS |
742 | return copy_stack_state(dst, src); |
743 | } | |
744 | ||
f4d7e40a AS |
745 | static int copy_verifier_state(struct bpf_verifier_state *dst_state, |
746 | const struct bpf_verifier_state *src) | |
747 | { | |
748 | struct bpf_func_state *dst; | |
b5dc0163 | 749 | u32 jmp_sz = sizeof(struct bpf_idx_pair) * src->jmp_history_cnt; |
f4d7e40a AS |
750 | int i, err; |
751 | ||
b5dc0163 AS |
752 | if (dst_state->jmp_history_cnt < src->jmp_history_cnt) { |
753 | kfree(dst_state->jmp_history); | |
754 | dst_state->jmp_history = kmalloc(jmp_sz, GFP_USER); | |
755 | if (!dst_state->jmp_history) | |
756 | return -ENOMEM; | |
757 | } | |
758 | memcpy(dst_state->jmp_history, src->jmp_history, jmp_sz); | |
759 | dst_state->jmp_history_cnt = src->jmp_history_cnt; | |
760 | ||
f4d7e40a AS |
761 | /* if dst has more stack frames then src frame, free them */ |
762 | for (i = src->curframe + 1; i <= dst_state->curframe; i++) { | |
763 | free_func_state(dst_state->frame[i]); | |
764 | dst_state->frame[i] = NULL; | |
765 | } | |
979d63d5 | 766 | dst_state->speculative = src->speculative; |
f4d7e40a | 767 | dst_state->curframe = src->curframe; |
d83525ca | 768 | dst_state->active_spin_lock = src->active_spin_lock; |
2589726d AS |
769 | dst_state->branches = src->branches; |
770 | dst_state->parent = src->parent; | |
b5dc0163 AS |
771 | dst_state->first_insn_idx = src->first_insn_idx; |
772 | dst_state->last_insn_idx = src->last_insn_idx; | |
f4d7e40a AS |
773 | for (i = 0; i <= src->curframe; i++) { |
774 | dst = dst_state->frame[i]; | |
775 | if (!dst) { | |
776 | dst = kzalloc(sizeof(*dst), GFP_KERNEL); | |
777 | if (!dst) | |
778 | return -ENOMEM; | |
779 | dst_state->frame[i] = dst; | |
780 | } | |
781 | err = copy_func_state(dst, src->frame[i]); | |
782 | if (err) | |
783 | return err; | |
784 | } | |
785 | return 0; | |
786 | } | |
787 | ||
2589726d AS |
788 | static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st) |
789 | { | |
790 | while (st) { | |
791 | u32 br = --st->branches; | |
792 | ||
793 | /* WARN_ON(br > 1) technically makes sense here, | |
794 | * but see comment in push_stack(), hence: | |
795 | */ | |
796 | WARN_ONCE((int)br < 0, | |
797 | "BUG update_branch_counts:branches_to_explore=%d\n", | |
798 | br); | |
799 | if (br) | |
800 | break; | |
801 | st = st->parent; | |
802 | } | |
803 | } | |
804 | ||
638f5b90 AS |
805 | static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx, |
806 | int *insn_idx) | |
807 | { | |
808 | struct bpf_verifier_state *cur = env->cur_state; | |
809 | struct bpf_verifier_stack_elem *elem, *head = env->head; | |
810 | int err; | |
17a52670 AS |
811 | |
812 | if (env->head == NULL) | |
638f5b90 | 813 | return -ENOENT; |
17a52670 | 814 | |
638f5b90 AS |
815 | if (cur) { |
816 | err = copy_verifier_state(cur, &head->st); | |
817 | if (err) | |
818 | return err; | |
819 | } | |
820 | if (insn_idx) | |
821 | *insn_idx = head->insn_idx; | |
17a52670 | 822 | if (prev_insn_idx) |
638f5b90 AS |
823 | *prev_insn_idx = head->prev_insn_idx; |
824 | elem = head->next; | |
1969db47 | 825 | free_verifier_state(&head->st, false); |
638f5b90 | 826 | kfree(head); |
17a52670 AS |
827 | env->head = elem; |
828 | env->stack_size--; | |
638f5b90 | 829 | return 0; |
17a52670 AS |
830 | } |
831 | ||
58e2af8b | 832 | static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env, |
979d63d5 DB |
833 | int insn_idx, int prev_insn_idx, |
834 | bool speculative) | |
17a52670 | 835 | { |
638f5b90 | 836 | struct bpf_verifier_state *cur = env->cur_state; |
58e2af8b | 837 | struct bpf_verifier_stack_elem *elem; |
638f5b90 | 838 | int err; |
17a52670 | 839 | |
638f5b90 | 840 | elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL); |
17a52670 AS |
841 | if (!elem) |
842 | goto err; | |
843 | ||
17a52670 AS |
844 | elem->insn_idx = insn_idx; |
845 | elem->prev_insn_idx = prev_insn_idx; | |
846 | elem->next = env->head; | |
847 | env->head = elem; | |
848 | env->stack_size++; | |
1969db47 AS |
849 | err = copy_verifier_state(&elem->st, cur); |
850 | if (err) | |
851 | goto err; | |
979d63d5 | 852 | elem->st.speculative |= speculative; |
b285fcb7 AS |
853 | if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) { |
854 | verbose(env, "The sequence of %d jumps is too complex.\n", | |
855 | env->stack_size); | |
17a52670 AS |
856 | goto err; |
857 | } | |
2589726d AS |
858 | if (elem->st.parent) { |
859 | ++elem->st.parent->branches; | |
860 | /* WARN_ON(branches > 2) technically makes sense here, | |
861 | * but | |
862 | * 1. speculative states will bump 'branches' for non-branch | |
863 | * instructions | |
864 | * 2. is_state_visited() heuristics may decide not to create | |
865 | * a new state for a sequence of branches and all such current | |
866 | * and cloned states will be pointing to a single parent state | |
867 | * which might have large 'branches' count. | |
868 | */ | |
869 | } | |
17a52670 AS |
870 | return &elem->st; |
871 | err: | |
5896351e AS |
872 | free_verifier_state(env->cur_state, true); |
873 | env->cur_state = NULL; | |
17a52670 | 874 | /* pop all elements and return */ |
638f5b90 | 875 | while (!pop_stack(env, NULL, NULL)); |
17a52670 AS |
876 | return NULL; |
877 | } | |
878 | ||
879 | #define CALLER_SAVED_REGS 6 | |
880 | static const int caller_saved[CALLER_SAVED_REGS] = { | |
881 | BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5 | |
882 | }; | |
883 | ||
f1174f77 EC |
884 | static void __mark_reg_not_init(struct bpf_reg_state *reg); |
885 | ||
b03c9f9f EC |
886 | /* Mark the unknown part of a register (variable offset or scalar value) as |
887 | * known to have the value @imm. | |
888 | */ | |
889 | static void __mark_reg_known(struct bpf_reg_state *reg, u64 imm) | |
890 | { | |
a9c676bc AS |
891 | /* Clear id, off, and union(map_ptr, range) */ |
892 | memset(((u8 *)reg) + sizeof(reg->type), 0, | |
893 | offsetof(struct bpf_reg_state, var_off) - sizeof(reg->type)); | |
b03c9f9f EC |
894 | reg->var_off = tnum_const(imm); |
895 | reg->smin_value = (s64)imm; | |
896 | reg->smax_value = (s64)imm; | |
897 | reg->umin_value = imm; | |
898 | reg->umax_value = imm; | |
899 | } | |
900 | ||
f1174f77 EC |
901 | /* Mark the 'variable offset' part of a register as zero. This should be |
902 | * used only on registers holding a pointer type. | |
903 | */ | |
904 | static void __mark_reg_known_zero(struct bpf_reg_state *reg) | |
a9789ef9 | 905 | { |
b03c9f9f | 906 | __mark_reg_known(reg, 0); |
f1174f77 | 907 | } |
a9789ef9 | 908 | |
cc2b14d5 AS |
909 | static void __mark_reg_const_zero(struct bpf_reg_state *reg) |
910 | { | |
911 | __mark_reg_known(reg, 0); | |
cc2b14d5 AS |
912 | reg->type = SCALAR_VALUE; |
913 | } | |
914 | ||
61bd5218 JK |
915 | static void mark_reg_known_zero(struct bpf_verifier_env *env, |
916 | struct bpf_reg_state *regs, u32 regno) | |
f1174f77 EC |
917 | { |
918 | if (WARN_ON(regno >= MAX_BPF_REG)) { | |
61bd5218 | 919 | verbose(env, "mark_reg_known_zero(regs, %u)\n", regno); |
f1174f77 EC |
920 | /* Something bad happened, let's kill all regs */ |
921 | for (regno = 0; regno < MAX_BPF_REG; regno++) | |
922 | __mark_reg_not_init(regs + regno); | |
923 | return; | |
924 | } | |
925 | __mark_reg_known_zero(regs + regno); | |
926 | } | |
927 | ||
de8f3a83 DB |
928 | static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg) |
929 | { | |
930 | return type_is_pkt_pointer(reg->type); | |
931 | } | |
932 | ||
933 | static bool reg_is_pkt_pointer_any(const struct bpf_reg_state *reg) | |
934 | { | |
935 | return reg_is_pkt_pointer(reg) || | |
936 | reg->type == PTR_TO_PACKET_END; | |
937 | } | |
938 | ||
939 | /* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */ | |
940 | static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg, | |
941 | enum bpf_reg_type which) | |
942 | { | |
943 | /* The register can already have a range from prior markings. | |
944 | * This is fine as long as it hasn't been advanced from its | |
945 | * origin. | |
946 | */ | |
947 | return reg->type == which && | |
948 | reg->id == 0 && | |
949 | reg->off == 0 && | |
950 | tnum_equals_const(reg->var_off, 0); | |
951 | } | |
952 | ||
b03c9f9f EC |
953 | /* Attempts to improve min/max values based on var_off information */ |
954 | static void __update_reg_bounds(struct bpf_reg_state *reg) | |
955 | { | |
956 | /* min signed is max(sign bit) | min(other bits) */ | |
957 | reg->smin_value = max_t(s64, reg->smin_value, | |
958 | reg->var_off.value | (reg->var_off.mask & S64_MIN)); | |
959 | /* max signed is min(sign bit) | max(other bits) */ | |
960 | reg->smax_value = min_t(s64, reg->smax_value, | |
961 | reg->var_off.value | (reg->var_off.mask & S64_MAX)); | |
962 | reg->umin_value = max(reg->umin_value, reg->var_off.value); | |
963 | reg->umax_value = min(reg->umax_value, | |
964 | reg->var_off.value | reg->var_off.mask); | |
965 | } | |
966 | ||
967 | /* Uses signed min/max values to inform unsigned, and vice-versa */ | |
968 | static void __reg_deduce_bounds(struct bpf_reg_state *reg) | |
969 | { | |
970 | /* Learn sign from signed bounds. | |
971 | * If we cannot cross the sign boundary, then signed and unsigned bounds | |
972 | * are the same, so combine. This works even in the negative case, e.g. | |
973 | * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff. | |
974 | */ | |
975 | if (reg->smin_value >= 0 || reg->smax_value < 0) { | |
976 | reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value, | |
977 | reg->umin_value); | |
978 | reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value, | |
979 | reg->umax_value); | |
980 | return; | |
981 | } | |
982 | /* Learn sign from unsigned bounds. Signed bounds cross the sign | |
983 | * boundary, so we must be careful. | |
984 | */ | |
985 | if ((s64)reg->umax_value >= 0) { | |
986 | /* Positive. We can't learn anything from the smin, but smax | |
987 | * is positive, hence safe. | |
988 | */ | |
989 | reg->smin_value = reg->umin_value; | |
990 | reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value, | |
991 | reg->umax_value); | |
992 | } else if ((s64)reg->umin_value < 0) { | |
993 | /* Negative. We can't learn anything from the smax, but smin | |
994 | * is negative, hence safe. | |
995 | */ | |
996 | reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value, | |
997 | reg->umin_value); | |
998 | reg->smax_value = reg->umax_value; | |
999 | } | |
1000 | } | |
1001 | ||
1002 | /* Attempts to improve var_off based on unsigned min/max information */ | |
1003 | static void __reg_bound_offset(struct bpf_reg_state *reg) | |
1004 | { | |
1005 | reg->var_off = tnum_intersect(reg->var_off, | |
1006 | tnum_range(reg->umin_value, | |
1007 | reg->umax_value)); | |
1008 | } | |
1009 | ||
1010 | /* Reset the min/max bounds of a register */ | |
1011 | static void __mark_reg_unbounded(struct bpf_reg_state *reg) | |
1012 | { | |
1013 | reg->smin_value = S64_MIN; | |
1014 | reg->smax_value = S64_MAX; | |
1015 | reg->umin_value = 0; | |
1016 | reg->umax_value = U64_MAX; | |
1017 | } | |
1018 | ||
f1174f77 EC |
1019 | /* Mark a register as having a completely unknown (scalar) value. */ |
1020 | static void __mark_reg_unknown(struct bpf_reg_state *reg) | |
1021 | { | |
a9c676bc AS |
1022 | /* |
1023 | * Clear type, id, off, and union(map_ptr, range) and | |
1024 | * padding between 'type' and union | |
1025 | */ | |
1026 | memset(reg, 0, offsetof(struct bpf_reg_state, var_off)); | |
f1174f77 | 1027 | reg->type = SCALAR_VALUE; |
f1174f77 | 1028 | reg->var_off = tnum_unknown; |
f4d7e40a | 1029 | reg->frameno = 0; |
b03c9f9f | 1030 | __mark_reg_unbounded(reg); |
f1174f77 EC |
1031 | } |
1032 | ||
61bd5218 JK |
1033 | static void mark_reg_unknown(struct bpf_verifier_env *env, |
1034 | struct bpf_reg_state *regs, u32 regno) | |
f1174f77 EC |
1035 | { |
1036 | if (WARN_ON(regno >= MAX_BPF_REG)) { | |
61bd5218 | 1037 | verbose(env, "mark_reg_unknown(regs, %u)\n", regno); |
19ceb417 AS |
1038 | /* Something bad happened, let's kill all regs except FP */ |
1039 | for (regno = 0; regno < BPF_REG_FP; regno++) | |
f1174f77 EC |
1040 | __mark_reg_not_init(regs + regno); |
1041 | return; | |
1042 | } | |
6754172c AS |
1043 | regs += regno; |
1044 | __mark_reg_unknown(regs); | |
1045 | /* constant backtracking is enabled for root without bpf2bpf calls */ | |
1046 | regs->precise = env->subprog_cnt > 1 || !env->allow_ptr_leaks ? | |
1047 | true : false; | |
f1174f77 EC |
1048 | } |
1049 | ||
1050 | static void __mark_reg_not_init(struct bpf_reg_state *reg) | |
1051 | { | |
1052 | __mark_reg_unknown(reg); | |
1053 | reg->type = NOT_INIT; | |
1054 | } | |
1055 | ||
61bd5218 JK |
1056 | static void mark_reg_not_init(struct bpf_verifier_env *env, |
1057 | struct bpf_reg_state *regs, u32 regno) | |
f1174f77 EC |
1058 | { |
1059 | if (WARN_ON(regno >= MAX_BPF_REG)) { | |
61bd5218 | 1060 | verbose(env, "mark_reg_not_init(regs, %u)\n", regno); |
19ceb417 AS |
1061 | /* Something bad happened, let's kill all regs except FP */ |
1062 | for (regno = 0; regno < BPF_REG_FP; regno++) | |
f1174f77 EC |
1063 | __mark_reg_not_init(regs + regno); |
1064 | return; | |
1065 | } | |
1066 | __mark_reg_not_init(regs + regno); | |
a9789ef9 DB |
1067 | } |
1068 | ||
5327ed3d | 1069 | #define DEF_NOT_SUBREG (0) |
61bd5218 | 1070 | static void init_reg_state(struct bpf_verifier_env *env, |
f4d7e40a | 1071 | struct bpf_func_state *state) |
17a52670 | 1072 | { |
f4d7e40a | 1073 | struct bpf_reg_state *regs = state->regs; |
17a52670 AS |
1074 | int i; |
1075 | ||
dc503a8a | 1076 | for (i = 0; i < MAX_BPF_REG; i++) { |
61bd5218 | 1077 | mark_reg_not_init(env, regs, i); |
dc503a8a | 1078 | regs[i].live = REG_LIVE_NONE; |
679c782d | 1079 | regs[i].parent = NULL; |
5327ed3d | 1080 | regs[i].subreg_def = DEF_NOT_SUBREG; |
dc503a8a | 1081 | } |
17a52670 AS |
1082 | |
1083 | /* frame pointer */ | |
f1174f77 | 1084 | regs[BPF_REG_FP].type = PTR_TO_STACK; |
61bd5218 | 1085 | mark_reg_known_zero(env, regs, BPF_REG_FP); |
f4d7e40a | 1086 | regs[BPF_REG_FP].frameno = state->frameno; |
17a52670 AS |
1087 | |
1088 | /* 1st arg to a function */ | |
1089 | regs[BPF_REG_1].type = PTR_TO_CTX; | |
61bd5218 | 1090 | mark_reg_known_zero(env, regs, BPF_REG_1); |
6760bf2d DB |
1091 | } |
1092 | ||
f4d7e40a AS |
1093 | #define BPF_MAIN_FUNC (-1) |
1094 | static void init_func_state(struct bpf_verifier_env *env, | |
1095 | struct bpf_func_state *state, | |
1096 | int callsite, int frameno, int subprogno) | |
1097 | { | |
1098 | state->callsite = callsite; | |
1099 | state->frameno = frameno; | |
1100 | state->subprogno = subprogno; | |
1101 | init_reg_state(env, state); | |
1102 | } | |
1103 | ||
17a52670 AS |
1104 | enum reg_arg_type { |
1105 | SRC_OP, /* register is used as source operand */ | |
1106 | DST_OP, /* register is used as destination operand */ | |
1107 | DST_OP_NO_MARK /* same as above, check only, don't mark */ | |
1108 | }; | |
1109 | ||
cc8b0b92 AS |
1110 | static int cmp_subprogs(const void *a, const void *b) |
1111 | { | |
9c8105bd JW |
1112 | return ((struct bpf_subprog_info *)a)->start - |
1113 | ((struct bpf_subprog_info *)b)->start; | |
cc8b0b92 AS |
1114 | } |
1115 | ||
1116 | static int find_subprog(struct bpf_verifier_env *env, int off) | |
1117 | { | |
9c8105bd | 1118 | struct bpf_subprog_info *p; |
cc8b0b92 | 1119 | |
9c8105bd JW |
1120 | p = bsearch(&off, env->subprog_info, env->subprog_cnt, |
1121 | sizeof(env->subprog_info[0]), cmp_subprogs); | |
cc8b0b92 AS |
1122 | if (!p) |
1123 | return -ENOENT; | |
9c8105bd | 1124 | return p - env->subprog_info; |
cc8b0b92 AS |
1125 | |
1126 | } | |
1127 | ||
1128 | static int add_subprog(struct bpf_verifier_env *env, int off) | |
1129 | { | |
1130 | int insn_cnt = env->prog->len; | |
1131 | int ret; | |
1132 | ||
1133 | if (off >= insn_cnt || off < 0) { | |
1134 | verbose(env, "call to invalid destination\n"); | |
1135 | return -EINVAL; | |
1136 | } | |
1137 | ret = find_subprog(env, off); | |
1138 | if (ret >= 0) | |
1139 | return 0; | |
4cb3d99c | 1140 | if (env->subprog_cnt >= BPF_MAX_SUBPROGS) { |
cc8b0b92 AS |
1141 | verbose(env, "too many subprograms\n"); |
1142 | return -E2BIG; | |
1143 | } | |
9c8105bd JW |
1144 | env->subprog_info[env->subprog_cnt++].start = off; |
1145 | sort(env->subprog_info, env->subprog_cnt, | |
1146 | sizeof(env->subprog_info[0]), cmp_subprogs, NULL); | |
cc8b0b92 AS |
1147 | return 0; |
1148 | } | |
1149 | ||
1150 | static int check_subprogs(struct bpf_verifier_env *env) | |
1151 | { | |
1152 | int i, ret, subprog_start, subprog_end, off, cur_subprog = 0; | |
9c8105bd | 1153 | struct bpf_subprog_info *subprog = env->subprog_info; |
cc8b0b92 AS |
1154 | struct bpf_insn *insn = env->prog->insnsi; |
1155 | int insn_cnt = env->prog->len; | |
1156 | ||
f910cefa JW |
1157 | /* Add entry function. */ |
1158 | ret = add_subprog(env, 0); | |
1159 | if (ret < 0) | |
1160 | return ret; | |
1161 | ||
cc8b0b92 AS |
1162 | /* determine subprog starts. The end is one before the next starts */ |
1163 | for (i = 0; i < insn_cnt; i++) { | |
1164 | if (insn[i].code != (BPF_JMP | BPF_CALL)) | |
1165 | continue; | |
1166 | if (insn[i].src_reg != BPF_PSEUDO_CALL) | |
1167 | continue; | |
1168 | if (!env->allow_ptr_leaks) { | |
1169 | verbose(env, "function calls to other bpf functions are allowed for root only\n"); | |
1170 | return -EPERM; | |
1171 | } | |
cc8b0b92 AS |
1172 | ret = add_subprog(env, i + insn[i].imm + 1); |
1173 | if (ret < 0) | |
1174 | return ret; | |
1175 | } | |
1176 | ||
4cb3d99c JW |
1177 | /* Add a fake 'exit' subprog which could simplify subprog iteration |
1178 | * logic. 'subprog_cnt' should not be increased. | |
1179 | */ | |
1180 | subprog[env->subprog_cnt].start = insn_cnt; | |
1181 | ||
06ee7115 | 1182 | if (env->log.level & BPF_LOG_LEVEL2) |
cc8b0b92 | 1183 | for (i = 0; i < env->subprog_cnt; i++) |
9c8105bd | 1184 | verbose(env, "func#%d @%d\n", i, subprog[i].start); |
cc8b0b92 AS |
1185 | |
1186 | /* now check that all jumps are within the same subprog */ | |
4cb3d99c JW |
1187 | subprog_start = subprog[cur_subprog].start; |
1188 | subprog_end = subprog[cur_subprog + 1].start; | |
cc8b0b92 AS |
1189 | for (i = 0; i < insn_cnt; i++) { |
1190 | u8 code = insn[i].code; | |
1191 | ||
092ed096 | 1192 | if (BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32) |
cc8b0b92 AS |
1193 | goto next; |
1194 | if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL) | |
1195 | goto next; | |
1196 | off = i + insn[i].off + 1; | |
1197 | if (off < subprog_start || off >= subprog_end) { | |
1198 | verbose(env, "jump out of range from insn %d to %d\n", i, off); | |
1199 | return -EINVAL; | |
1200 | } | |
1201 | next: | |
1202 | if (i == subprog_end - 1) { | |
1203 | /* to avoid fall-through from one subprog into another | |
1204 | * the last insn of the subprog should be either exit | |
1205 | * or unconditional jump back | |
1206 | */ | |
1207 | if (code != (BPF_JMP | BPF_EXIT) && | |
1208 | code != (BPF_JMP | BPF_JA)) { | |
1209 | verbose(env, "last insn is not an exit or jmp\n"); | |
1210 | return -EINVAL; | |
1211 | } | |
1212 | subprog_start = subprog_end; | |
4cb3d99c JW |
1213 | cur_subprog++; |
1214 | if (cur_subprog < env->subprog_cnt) | |
9c8105bd | 1215 | subprog_end = subprog[cur_subprog + 1].start; |
cc8b0b92 AS |
1216 | } |
1217 | } | |
1218 | return 0; | |
1219 | } | |
1220 | ||
679c782d EC |
1221 | /* Parentage chain of this register (or stack slot) should take care of all |
1222 | * issues like callee-saved registers, stack slot allocation time, etc. | |
1223 | */ | |
f4d7e40a | 1224 | static int mark_reg_read(struct bpf_verifier_env *env, |
679c782d | 1225 | const struct bpf_reg_state *state, |
5327ed3d | 1226 | struct bpf_reg_state *parent, u8 flag) |
f4d7e40a AS |
1227 | { |
1228 | bool writes = parent == state->parent; /* Observe write marks */ | |
06ee7115 | 1229 | int cnt = 0; |
dc503a8a EC |
1230 | |
1231 | while (parent) { | |
1232 | /* if read wasn't screened by an earlier write ... */ | |
679c782d | 1233 | if (writes && state->live & REG_LIVE_WRITTEN) |
dc503a8a | 1234 | break; |
9242b5f5 AS |
1235 | if (parent->live & REG_LIVE_DONE) { |
1236 | verbose(env, "verifier BUG type %s var_off %lld off %d\n", | |
1237 | reg_type_str[parent->type], | |
1238 | parent->var_off.value, parent->off); | |
1239 | return -EFAULT; | |
1240 | } | |
5327ed3d JW |
1241 | /* The first condition is more likely to be true than the |
1242 | * second, checked it first. | |
1243 | */ | |
1244 | if ((parent->live & REG_LIVE_READ) == flag || | |
1245 | parent->live & REG_LIVE_READ64) | |
25af32da AS |
1246 | /* The parentage chain never changes and |
1247 | * this parent was already marked as LIVE_READ. | |
1248 | * There is no need to keep walking the chain again and | |
1249 | * keep re-marking all parents as LIVE_READ. | |
1250 | * This case happens when the same register is read | |
1251 | * multiple times without writes into it in-between. | |
5327ed3d JW |
1252 | * Also, if parent has the stronger REG_LIVE_READ64 set, |
1253 | * then no need to set the weak REG_LIVE_READ32. | |
25af32da AS |
1254 | */ |
1255 | break; | |
dc503a8a | 1256 | /* ... then we depend on parent's value */ |
5327ed3d JW |
1257 | parent->live |= flag; |
1258 | /* REG_LIVE_READ64 overrides REG_LIVE_READ32. */ | |
1259 | if (flag == REG_LIVE_READ64) | |
1260 | parent->live &= ~REG_LIVE_READ32; | |
dc503a8a EC |
1261 | state = parent; |
1262 | parent = state->parent; | |
f4d7e40a | 1263 | writes = true; |
06ee7115 | 1264 | cnt++; |
dc503a8a | 1265 | } |
06ee7115 AS |
1266 | |
1267 | if (env->longest_mark_read_walk < cnt) | |
1268 | env->longest_mark_read_walk = cnt; | |
f4d7e40a | 1269 | return 0; |
dc503a8a EC |
1270 | } |
1271 | ||
5327ed3d JW |
1272 | /* This function is supposed to be used by the following 32-bit optimization |
1273 | * code only. It returns TRUE if the source or destination register operates | |
1274 | * on 64-bit, otherwise return FALSE. | |
1275 | */ | |
1276 | static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn, | |
1277 | u32 regno, struct bpf_reg_state *reg, enum reg_arg_type t) | |
1278 | { | |
1279 | u8 code, class, op; | |
1280 | ||
1281 | code = insn->code; | |
1282 | class = BPF_CLASS(code); | |
1283 | op = BPF_OP(code); | |
1284 | if (class == BPF_JMP) { | |
1285 | /* BPF_EXIT for "main" will reach here. Return TRUE | |
1286 | * conservatively. | |
1287 | */ | |
1288 | if (op == BPF_EXIT) | |
1289 | return true; | |
1290 | if (op == BPF_CALL) { | |
1291 | /* BPF to BPF call will reach here because of marking | |
1292 | * caller saved clobber with DST_OP_NO_MARK for which we | |
1293 | * don't care the register def because they are anyway | |
1294 | * marked as NOT_INIT already. | |
1295 | */ | |
1296 | if (insn->src_reg == BPF_PSEUDO_CALL) | |
1297 | return false; | |
1298 | /* Helper call will reach here because of arg type | |
1299 | * check, conservatively return TRUE. | |
1300 | */ | |
1301 | if (t == SRC_OP) | |
1302 | return true; | |
1303 | ||
1304 | return false; | |
1305 | } | |
1306 | } | |
1307 | ||
1308 | if (class == BPF_ALU64 || class == BPF_JMP || | |
1309 | /* BPF_END always use BPF_ALU class. */ | |
1310 | (class == BPF_ALU && op == BPF_END && insn->imm == 64)) | |
1311 | return true; | |
1312 | ||
1313 | if (class == BPF_ALU || class == BPF_JMP32) | |
1314 | return false; | |
1315 | ||
1316 | if (class == BPF_LDX) { | |
1317 | if (t != SRC_OP) | |
1318 | return BPF_SIZE(code) == BPF_DW; | |
1319 | /* LDX source must be ptr. */ | |
1320 | return true; | |
1321 | } | |
1322 | ||
1323 | if (class == BPF_STX) { | |
1324 | if (reg->type != SCALAR_VALUE) | |
1325 | return true; | |
1326 | return BPF_SIZE(code) == BPF_DW; | |
1327 | } | |
1328 | ||
1329 | if (class == BPF_LD) { | |
1330 | u8 mode = BPF_MODE(code); | |
1331 | ||
1332 | /* LD_IMM64 */ | |
1333 | if (mode == BPF_IMM) | |
1334 | return true; | |
1335 | ||
1336 | /* Both LD_IND and LD_ABS return 32-bit data. */ | |
1337 | if (t != SRC_OP) | |
1338 | return false; | |
1339 | ||
1340 | /* Implicit ctx ptr. */ | |
1341 | if (regno == BPF_REG_6) | |
1342 | return true; | |
1343 | ||
1344 | /* Explicit source could be any width. */ | |
1345 | return true; | |
1346 | } | |
1347 | ||
1348 | if (class == BPF_ST) | |
1349 | /* The only source register for BPF_ST is a ptr. */ | |
1350 | return true; | |
1351 | ||
1352 | /* Conservatively return true at default. */ | |
1353 | return true; | |
1354 | } | |
1355 | ||
b325fbca JW |
1356 | /* Return TRUE if INSN doesn't have explicit value define. */ |
1357 | static bool insn_no_def(struct bpf_insn *insn) | |
1358 | { | |
1359 | u8 class = BPF_CLASS(insn->code); | |
1360 | ||
1361 | return (class == BPF_JMP || class == BPF_JMP32 || | |
1362 | class == BPF_STX || class == BPF_ST); | |
1363 | } | |
1364 | ||
1365 | /* Return TRUE if INSN has defined any 32-bit value explicitly. */ | |
1366 | static bool insn_has_def32(struct bpf_verifier_env *env, struct bpf_insn *insn) | |
1367 | { | |
1368 | if (insn_no_def(insn)) | |
1369 | return false; | |
1370 | ||
1371 | return !is_reg64(env, insn, insn->dst_reg, NULL, DST_OP); | |
1372 | } | |
1373 | ||
5327ed3d JW |
1374 | static void mark_insn_zext(struct bpf_verifier_env *env, |
1375 | struct bpf_reg_state *reg) | |
1376 | { | |
1377 | s32 def_idx = reg->subreg_def; | |
1378 | ||
1379 | if (def_idx == DEF_NOT_SUBREG) | |
1380 | return; | |
1381 | ||
1382 | env->insn_aux_data[def_idx - 1].zext_dst = true; | |
1383 | /* The dst will be zero extended, so won't be sub-register anymore. */ | |
1384 | reg->subreg_def = DEF_NOT_SUBREG; | |
1385 | } | |
1386 | ||
dc503a8a | 1387 | static int check_reg_arg(struct bpf_verifier_env *env, u32 regno, |
17a52670 AS |
1388 | enum reg_arg_type t) |
1389 | { | |
f4d7e40a AS |
1390 | struct bpf_verifier_state *vstate = env->cur_state; |
1391 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
5327ed3d | 1392 | struct bpf_insn *insn = env->prog->insnsi + env->insn_idx; |
c342dc10 | 1393 | struct bpf_reg_state *reg, *regs = state->regs; |
5327ed3d | 1394 | bool rw64; |
dc503a8a | 1395 | |
17a52670 | 1396 | if (regno >= MAX_BPF_REG) { |
61bd5218 | 1397 | verbose(env, "R%d is invalid\n", regno); |
17a52670 AS |
1398 | return -EINVAL; |
1399 | } | |
1400 | ||
c342dc10 | 1401 | reg = ®s[regno]; |
5327ed3d | 1402 | rw64 = is_reg64(env, insn, regno, reg, t); |
17a52670 AS |
1403 | if (t == SRC_OP) { |
1404 | /* check whether register used as source operand can be read */ | |
c342dc10 | 1405 | if (reg->type == NOT_INIT) { |
61bd5218 | 1406 | verbose(env, "R%d !read_ok\n", regno); |
17a52670 AS |
1407 | return -EACCES; |
1408 | } | |
679c782d | 1409 | /* We don't need to worry about FP liveness because it's read-only */ |
c342dc10 JW |
1410 | if (regno == BPF_REG_FP) |
1411 | return 0; | |
1412 | ||
5327ed3d JW |
1413 | if (rw64) |
1414 | mark_insn_zext(env, reg); | |
1415 | ||
1416 | return mark_reg_read(env, reg, reg->parent, | |
1417 | rw64 ? REG_LIVE_READ64 : REG_LIVE_READ32); | |
17a52670 AS |
1418 | } else { |
1419 | /* check whether register used as dest operand can be written to */ | |
1420 | if (regno == BPF_REG_FP) { | |
61bd5218 | 1421 | verbose(env, "frame pointer is read only\n"); |
17a52670 AS |
1422 | return -EACCES; |
1423 | } | |
c342dc10 | 1424 | reg->live |= REG_LIVE_WRITTEN; |
5327ed3d | 1425 | reg->subreg_def = rw64 ? DEF_NOT_SUBREG : env->insn_idx + 1; |
17a52670 | 1426 | if (t == DST_OP) |
61bd5218 | 1427 | mark_reg_unknown(env, regs, regno); |
17a52670 AS |
1428 | } |
1429 | return 0; | |
1430 | } | |
1431 | ||
b5dc0163 AS |
1432 | /* for any branch, call, exit record the history of jmps in the given state */ |
1433 | static int push_jmp_history(struct bpf_verifier_env *env, | |
1434 | struct bpf_verifier_state *cur) | |
1435 | { | |
1436 | u32 cnt = cur->jmp_history_cnt; | |
1437 | struct bpf_idx_pair *p; | |
1438 | ||
1439 | cnt++; | |
1440 | p = krealloc(cur->jmp_history, cnt * sizeof(*p), GFP_USER); | |
1441 | if (!p) | |
1442 | return -ENOMEM; | |
1443 | p[cnt - 1].idx = env->insn_idx; | |
1444 | p[cnt - 1].prev_idx = env->prev_insn_idx; | |
1445 | cur->jmp_history = p; | |
1446 | cur->jmp_history_cnt = cnt; | |
1447 | return 0; | |
1448 | } | |
1449 | ||
1450 | /* Backtrack one insn at a time. If idx is not at the top of recorded | |
1451 | * history then previous instruction came from straight line execution. | |
1452 | */ | |
1453 | static int get_prev_insn_idx(struct bpf_verifier_state *st, int i, | |
1454 | u32 *history) | |
1455 | { | |
1456 | u32 cnt = *history; | |
1457 | ||
1458 | if (cnt && st->jmp_history[cnt - 1].idx == i) { | |
1459 | i = st->jmp_history[cnt - 1].prev_idx; | |
1460 | (*history)--; | |
1461 | } else { | |
1462 | i--; | |
1463 | } | |
1464 | return i; | |
1465 | } | |
1466 | ||
1467 | /* For given verifier state backtrack_insn() is called from the last insn to | |
1468 | * the first insn. Its purpose is to compute a bitmask of registers and | |
1469 | * stack slots that needs precision in the parent verifier state. | |
1470 | */ | |
1471 | static int backtrack_insn(struct bpf_verifier_env *env, int idx, | |
1472 | u32 *reg_mask, u64 *stack_mask) | |
1473 | { | |
1474 | const struct bpf_insn_cbs cbs = { | |
1475 | .cb_print = verbose, | |
1476 | .private_data = env, | |
1477 | }; | |
1478 | struct bpf_insn *insn = env->prog->insnsi + idx; | |
1479 | u8 class = BPF_CLASS(insn->code); | |
1480 | u8 opcode = BPF_OP(insn->code); | |
1481 | u8 mode = BPF_MODE(insn->code); | |
1482 | u32 dreg = 1u << insn->dst_reg; | |
1483 | u32 sreg = 1u << insn->src_reg; | |
1484 | u32 spi; | |
1485 | ||
1486 | if (insn->code == 0) | |
1487 | return 0; | |
1488 | if (env->log.level & BPF_LOG_LEVEL) { | |
1489 | verbose(env, "regs=%x stack=%llx before ", *reg_mask, *stack_mask); | |
1490 | verbose(env, "%d: ", idx); | |
1491 | print_bpf_insn(&cbs, insn, env->allow_ptr_leaks); | |
1492 | } | |
1493 | ||
1494 | if (class == BPF_ALU || class == BPF_ALU64) { | |
1495 | if (!(*reg_mask & dreg)) | |
1496 | return 0; | |
1497 | if (opcode == BPF_MOV) { | |
1498 | if (BPF_SRC(insn->code) == BPF_X) { | |
1499 | /* dreg = sreg | |
1500 | * dreg needs precision after this insn | |
1501 | * sreg needs precision before this insn | |
1502 | */ | |
1503 | *reg_mask &= ~dreg; | |
1504 | *reg_mask |= sreg; | |
1505 | } else { | |
1506 | /* dreg = K | |
1507 | * dreg needs precision after this insn. | |
1508 | * Corresponding register is already marked | |
1509 | * as precise=true in this verifier state. | |
1510 | * No further markings in parent are necessary | |
1511 | */ | |
1512 | *reg_mask &= ~dreg; | |
1513 | } | |
1514 | } else { | |
1515 | if (BPF_SRC(insn->code) == BPF_X) { | |
1516 | /* dreg += sreg | |
1517 | * both dreg and sreg need precision | |
1518 | * before this insn | |
1519 | */ | |
1520 | *reg_mask |= sreg; | |
1521 | } /* else dreg += K | |
1522 | * dreg still needs precision before this insn | |
1523 | */ | |
1524 | } | |
1525 | } else if (class == BPF_LDX) { | |
1526 | if (!(*reg_mask & dreg)) | |
1527 | return 0; | |
1528 | *reg_mask &= ~dreg; | |
1529 | ||
1530 | /* scalars can only be spilled into stack w/o losing precision. | |
1531 | * Load from any other memory can be zero extended. | |
1532 | * The desire to keep that precision is already indicated | |
1533 | * by 'precise' mark in corresponding register of this state. | |
1534 | * No further tracking necessary. | |
1535 | */ | |
1536 | if (insn->src_reg != BPF_REG_FP) | |
1537 | return 0; | |
1538 | if (BPF_SIZE(insn->code) != BPF_DW) | |
1539 | return 0; | |
1540 | ||
1541 | /* dreg = *(u64 *)[fp - off] was a fill from the stack. | |
1542 | * that [fp - off] slot contains scalar that needs to be | |
1543 | * tracked with precision | |
1544 | */ | |
1545 | spi = (-insn->off - 1) / BPF_REG_SIZE; | |
1546 | if (spi >= 64) { | |
1547 | verbose(env, "BUG spi %d\n", spi); | |
1548 | WARN_ONCE(1, "verifier backtracking bug"); | |
1549 | return -EFAULT; | |
1550 | } | |
1551 | *stack_mask |= 1ull << spi; | |
b3b50f05 | 1552 | } else if (class == BPF_STX || class == BPF_ST) { |
b5dc0163 | 1553 | if (*reg_mask & dreg) |
b3b50f05 | 1554 | /* stx & st shouldn't be using _scalar_ dst_reg |
b5dc0163 AS |
1555 | * to access memory. It means backtracking |
1556 | * encountered a case of pointer subtraction. | |
1557 | */ | |
1558 | return -ENOTSUPP; | |
1559 | /* scalars can only be spilled into stack */ | |
1560 | if (insn->dst_reg != BPF_REG_FP) | |
1561 | return 0; | |
1562 | if (BPF_SIZE(insn->code) != BPF_DW) | |
1563 | return 0; | |
1564 | spi = (-insn->off - 1) / BPF_REG_SIZE; | |
1565 | if (spi >= 64) { | |
1566 | verbose(env, "BUG spi %d\n", spi); | |
1567 | WARN_ONCE(1, "verifier backtracking bug"); | |
1568 | return -EFAULT; | |
1569 | } | |
1570 | if (!(*stack_mask & (1ull << spi))) | |
1571 | return 0; | |
1572 | *stack_mask &= ~(1ull << spi); | |
b3b50f05 AN |
1573 | if (class == BPF_STX) |
1574 | *reg_mask |= sreg; | |
b5dc0163 AS |
1575 | } else if (class == BPF_JMP || class == BPF_JMP32) { |
1576 | if (opcode == BPF_CALL) { | |
1577 | if (insn->src_reg == BPF_PSEUDO_CALL) | |
1578 | return -ENOTSUPP; | |
1579 | /* regular helper call sets R0 */ | |
1580 | *reg_mask &= ~1; | |
1581 | if (*reg_mask & 0x3f) { | |
1582 | /* if backtracing was looking for registers R1-R5 | |
1583 | * they should have been found already. | |
1584 | */ | |
1585 | verbose(env, "BUG regs %x\n", *reg_mask); | |
1586 | WARN_ONCE(1, "verifier backtracking bug"); | |
1587 | return -EFAULT; | |
1588 | } | |
1589 | } else if (opcode == BPF_EXIT) { | |
1590 | return -ENOTSUPP; | |
1591 | } | |
1592 | } else if (class == BPF_LD) { | |
1593 | if (!(*reg_mask & dreg)) | |
1594 | return 0; | |
1595 | *reg_mask &= ~dreg; | |
1596 | /* It's ld_imm64 or ld_abs or ld_ind. | |
1597 | * For ld_imm64 no further tracking of precision | |
1598 | * into parent is necessary | |
1599 | */ | |
1600 | if (mode == BPF_IND || mode == BPF_ABS) | |
1601 | /* to be analyzed */ | |
1602 | return -ENOTSUPP; | |
b5dc0163 AS |
1603 | } |
1604 | return 0; | |
1605 | } | |
1606 | ||
1607 | /* the scalar precision tracking algorithm: | |
1608 | * . at the start all registers have precise=false. | |
1609 | * . scalar ranges are tracked as normal through alu and jmp insns. | |
1610 | * . once precise value of the scalar register is used in: | |
1611 | * . ptr + scalar alu | |
1612 | * . if (scalar cond K|scalar) | |
1613 | * . helper_call(.., scalar, ...) where ARG_CONST is expected | |
1614 | * backtrack through the verifier states and mark all registers and | |
1615 | * stack slots with spilled constants that these scalar regisers | |
1616 | * should be precise. | |
1617 | * . during state pruning two registers (or spilled stack slots) | |
1618 | * are equivalent if both are not precise. | |
1619 | * | |
1620 | * Note the verifier cannot simply walk register parentage chain, | |
1621 | * since many different registers and stack slots could have been | |
1622 | * used to compute single precise scalar. | |
1623 | * | |
1624 | * The approach of starting with precise=true for all registers and then | |
1625 | * backtrack to mark a register as not precise when the verifier detects | |
1626 | * that program doesn't care about specific value (e.g., when helper | |
1627 | * takes register as ARG_ANYTHING parameter) is not safe. | |
1628 | * | |
1629 | * It's ok to walk single parentage chain of the verifier states. | |
1630 | * It's possible that this backtracking will go all the way till 1st insn. | |
1631 | * All other branches will be explored for needing precision later. | |
1632 | * | |
1633 | * The backtracking needs to deal with cases like: | |
1634 | * 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) | |
1635 | * r9 -= r8 | |
1636 | * r5 = r9 | |
1637 | * if r5 > 0x79f goto pc+7 | |
1638 | * R5_w=inv(id=0,umax_value=1951,var_off=(0x0; 0x7ff)) | |
1639 | * r5 += 1 | |
1640 | * ... | |
1641 | * call bpf_perf_event_output#25 | |
1642 | * where .arg5_type = ARG_CONST_SIZE_OR_ZERO | |
1643 | * | |
1644 | * and this case: | |
1645 | * r6 = 1 | |
1646 | * call foo // uses callee's r6 inside to compute r0 | |
1647 | * r0 += r6 | |
1648 | * if r0 == 0 goto | |
1649 | * | |
1650 | * to track above reg_mask/stack_mask needs to be independent for each frame. | |
1651 | * | |
1652 | * Also if parent's curframe > frame where backtracking started, | |
1653 | * the verifier need to mark registers in both frames, otherwise callees | |
1654 | * may incorrectly prune callers. This is similar to | |
1655 | * commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences") | |
1656 | * | |
1657 | * For now backtracking falls back into conservative marking. | |
1658 | */ | |
1659 | static void mark_all_scalars_precise(struct bpf_verifier_env *env, | |
1660 | struct bpf_verifier_state *st) | |
1661 | { | |
1662 | struct bpf_func_state *func; | |
1663 | struct bpf_reg_state *reg; | |
1664 | int i, j; | |
1665 | ||
1666 | /* big hammer: mark all scalars precise in this path. | |
1667 | * pop_stack may still get !precise scalars. | |
1668 | */ | |
1669 | for (; st; st = st->parent) | |
1670 | for (i = 0; i <= st->curframe; i++) { | |
1671 | func = st->frame[i]; | |
1672 | for (j = 0; j < BPF_REG_FP; j++) { | |
1673 | reg = &func->regs[j]; | |
1674 | if (reg->type != SCALAR_VALUE) | |
1675 | continue; | |
1676 | reg->precise = true; | |
1677 | } | |
1678 | for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) { | |
1679 | if (func->stack[j].slot_type[0] != STACK_SPILL) | |
1680 | continue; | |
1681 | reg = &func->stack[j].spilled_ptr; | |
1682 | if (reg->type != SCALAR_VALUE) | |
1683 | continue; | |
1684 | reg->precise = true; | |
1685 | } | |
1686 | } | |
1687 | } | |
1688 | ||
a3ce685d AS |
1689 | static int __mark_chain_precision(struct bpf_verifier_env *env, int regno, |
1690 | int spi) | |
b5dc0163 AS |
1691 | { |
1692 | struct bpf_verifier_state *st = env->cur_state; | |
1693 | int first_idx = st->first_insn_idx; | |
1694 | int last_idx = env->insn_idx; | |
1695 | struct bpf_func_state *func; | |
1696 | struct bpf_reg_state *reg; | |
a3ce685d AS |
1697 | u32 reg_mask = regno >= 0 ? 1u << regno : 0; |
1698 | u64 stack_mask = spi >= 0 ? 1ull << spi : 0; | |
b5dc0163 | 1699 | bool skip_first = true; |
a3ce685d | 1700 | bool new_marks = false; |
b5dc0163 AS |
1701 | int i, err; |
1702 | ||
1703 | if (!env->allow_ptr_leaks) | |
1704 | /* backtracking is root only for now */ | |
1705 | return 0; | |
1706 | ||
1707 | func = st->frame[st->curframe]; | |
a3ce685d AS |
1708 | if (regno >= 0) { |
1709 | reg = &func->regs[regno]; | |
1710 | if (reg->type != SCALAR_VALUE) { | |
1711 | WARN_ONCE(1, "backtracing misuse"); | |
1712 | return -EFAULT; | |
1713 | } | |
1714 | if (!reg->precise) | |
1715 | new_marks = true; | |
1716 | else | |
1717 | reg_mask = 0; | |
1718 | reg->precise = true; | |
b5dc0163 | 1719 | } |
b5dc0163 | 1720 | |
a3ce685d AS |
1721 | while (spi >= 0) { |
1722 | if (func->stack[spi].slot_type[0] != STACK_SPILL) { | |
1723 | stack_mask = 0; | |
1724 | break; | |
1725 | } | |
1726 | reg = &func->stack[spi].spilled_ptr; | |
1727 | if (reg->type != SCALAR_VALUE) { | |
1728 | stack_mask = 0; | |
1729 | break; | |
1730 | } | |
1731 | if (!reg->precise) | |
1732 | new_marks = true; | |
1733 | else | |
1734 | stack_mask = 0; | |
1735 | reg->precise = true; | |
1736 | break; | |
1737 | } | |
1738 | ||
1739 | if (!new_marks) | |
1740 | return 0; | |
1741 | if (!reg_mask && !stack_mask) | |
1742 | return 0; | |
b5dc0163 AS |
1743 | for (;;) { |
1744 | DECLARE_BITMAP(mask, 64); | |
b5dc0163 AS |
1745 | u32 history = st->jmp_history_cnt; |
1746 | ||
1747 | if (env->log.level & BPF_LOG_LEVEL) | |
1748 | verbose(env, "last_idx %d first_idx %d\n", last_idx, first_idx); | |
1749 | for (i = last_idx;;) { | |
1750 | if (skip_first) { | |
1751 | err = 0; | |
1752 | skip_first = false; | |
1753 | } else { | |
1754 | err = backtrack_insn(env, i, ®_mask, &stack_mask); | |
1755 | } | |
1756 | if (err == -ENOTSUPP) { | |
1757 | mark_all_scalars_precise(env, st); | |
1758 | return 0; | |
1759 | } else if (err) { | |
1760 | return err; | |
1761 | } | |
1762 | if (!reg_mask && !stack_mask) | |
1763 | /* Found assignment(s) into tracked register in this state. | |
1764 | * Since this state is already marked, just return. | |
1765 | * Nothing to be tracked further in the parent state. | |
1766 | */ | |
1767 | return 0; | |
1768 | if (i == first_idx) | |
1769 | break; | |
1770 | i = get_prev_insn_idx(st, i, &history); | |
1771 | if (i >= env->prog->len) { | |
1772 | /* This can happen if backtracking reached insn 0 | |
1773 | * and there are still reg_mask or stack_mask | |
1774 | * to backtrack. | |
1775 | * It means the backtracking missed the spot where | |
1776 | * particular register was initialized with a constant. | |
1777 | */ | |
1778 | verbose(env, "BUG backtracking idx %d\n", i); | |
1779 | WARN_ONCE(1, "verifier backtracking bug"); | |
1780 | return -EFAULT; | |
1781 | } | |
1782 | } | |
1783 | st = st->parent; | |
1784 | if (!st) | |
1785 | break; | |
1786 | ||
a3ce685d | 1787 | new_marks = false; |
b5dc0163 AS |
1788 | func = st->frame[st->curframe]; |
1789 | bitmap_from_u64(mask, reg_mask); | |
1790 | for_each_set_bit(i, mask, 32) { | |
1791 | reg = &func->regs[i]; | |
a3ce685d AS |
1792 | if (reg->type != SCALAR_VALUE) { |
1793 | reg_mask &= ~(1u << i); | |
b5dc0163 | 1794 | continue; |
a3ce685d | 1795 | } |
b5dc0163 AS |
1796 | if (!reg->precise) |
1797 | new_marks = true; | |
1798 | reg->precise = true; | |
1799 | } | |
1800 | ||
1801 | bitmap_from_u64(mask, stack_mask); | |
1802 | for_each_set_bit(i, mask, 64) { | |
1803 | if (i >= func->allocated_stack / BPF_REG_SIZE) { | |
2339cd6c AS |
1804 | /* the sequence of instructions: |
1805 | * 2: (bf) r3 = r10 | |
1806 | * 3: (7b) *(u64 *)(r3 -8) = r0 | |
1807 | * 4: (79) r4 = *(u64 *)(r10 -8) | |
1808 | * doesn't contain jmps. It's backtracked | |
1809 | * as a single block. | |
1810 | * During backtracking insn 3 is not recognized as | |
1811 | * stack access, so at the end of backtracking | |
1812 | * stack slot fp-8 is still marked in stack_mask. | |
1813 | * However the parent state may not have accessed | |
1814 | * fp-8 and it's "unallocated" stack space. | |
1815 | * In such case fallback to conservative. | |
b5dc0163 | 1816 | */ |
2339cd6c AS |
1817 | mark_all_scalars_precise(env, st); |
1818 | return 0; | |
b5dc0163 AS |
1819 | } |
1820 | ||
a3ce685d AS |
1821 | if (func->stack[i].slot_type[0] != STACK_SPILL) { |
1822 | stack_mask &= ~(1ull << i); | |
b5dc0163 | 1823 | continue; |
a3ce685d | 1824 | } |
b5dc0163 | 1825 | reg = &func->stack[i].spilled_ptr; |
a3ce685d AS |
1826 | if (reg->type != SCALAR_VALUE) { |
1827 | stack_mask &= ~(1ull << i); | |
b5dc0163 | 1828 | continue; |
a3ce685d | 1829 | } |
b5dc0163 AS |
1830 | if (!reg->precise) |
1831 | new_marks = true; | |
1832 | reg->precise = true; | |
1833 | } | |
1834 | if (env->log.level & BPF_LOG_LEVEL) { | |
1835 | print_verifier_state(env, func); | |
1836 | verbose(env, "parent %s regs=%x stack=%llx marks\n", | |
1837 | new_marks ? "didn't have" : "already had", | |
1838 | reg_mask, stack_mask); | |
1839 | } | |
1840 | ||
a3ce685d AS |
1841 | if (!reg_mask && !stack_mask) |
1842 | break; | |
b5dc0163 AS |
1843 | if (!new_marks) |
1844 | break; | |
1845 | ||
1846 | last_idx = st->last_insn_idx; | |
1847 | first_idx = st->first_insn_idx; | |
1848 | } | |
1849 | return 0; | |
1850 | } | |
1851 | ||
a3ce685d AS |
1852 | static int mark_chain_precision(struct bpf_verifier_env *env, int regno) |
1853 | { | |
1854 | return __mark_chain_precision(env, regno, -1); | |
1855 | } | |
1856 | ||
1857 | static int mark_chain_precision_stack(struct bpf_verifier_env *env, int spi) | |
1858 | { | |
1859 | return __mark_chain_precision(env, -1, spi); | |
1860 | } | |
b5dc0163 | 1861 | |
1be7f75d AS |
1862 | static bool is_spillable_regtype(enum bpf_reg_type type) |
1863 | { | |
1864 | switch (type) { | |
1865 | case PTR_TO_MAP_VALUE: | |
1866 | case PTR_TO_MAP_VALUE_OR_NULL: | |
1867 | case PTR_TO_STACK: | |
1868 | case PTR_TO_CTX: | |
969bf05e | 1869 | case PTR_TO_PACKET: |
de8f3a83 | 1870 | case PTR_TO_PACKET_META: |
969bf05e | 1871 | case PTR_TO_PACKET_END: |
d58e468b | 1872 | case PTR_TO_FLOW_KEYS: |
1be7f75d | 1873 | case CONST_PTR_TO_MAP: |
c64b7983 JS |
1874 | case PTR_TO_SOCKET: |
1875 | case PTR_TO_SOCKET_OR_NULL: | |
46f8bc92 MKL |
1876 | case PTR_TO_SOCK_COMMON: |
1877 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
655a51e5 MKL |
1878 | case PTR_TO_TCP_SOCK: |
1879 | case PTR_TO_TCP_SOCK_OR_NULL: | |
fada7fdc | 1880 | case PTR_TO_XDP_SOCK: |
1be7f75d AS |
1881 | return true; |
1882 | default: | |
1883 | return false; | |
1884 | } | |
1885 | } | |
1886 | ||
cc2b14d5 AS |
1887 | /* Does this register contain a constant zero? */ |
1888 | static bool register_is_null(struct bpf_reg_state *reg) | |
1889 | { | |
1890 | return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0); | |
1891 | } | |
1892 | ||
f7cf25b2 AS |
1893 | static bool register_is_const(struct bpf_reg_state *reg) |
1894 | { | |
1895 | return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off); | |
1896 | } | |
1897 | ||
1898 | static void save_register_state(struct bpf_func_state *state, | |
1899 | int spi, struct bpf_reg_state *reg) | |
1900 | { | |
1901 | int i; | |
1902 | ||
1903 | state->stack[spi].spilled_ptr = *reg; | |
1904 | state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN; | |
1905 | ||
1906 | for (i = 0; i < BPF_REG_SIZE; i++) | |
1907 | state->stack[spi].slot_type[i] = STACK_SPILL; | |
1908 | } | |
1909 | ||
17a52670 AS |
1910 | /* check_stack_read/write functions track spill/fill of registers, |
1911 | * stack boundary and alignment are checked in check_mem_access() | |
1912 | */ | |
61bd5218 | 1913 | static int check_stack_write(struct bpf_verifier_env *env, |
f4d7e40a | 1914 | struct bpf_func_state *state, /* func where register points to */ |
af86ca4e | 1915 | int off, int size, int value_regno, int insn_idx) |
17a52670 | 1916 | { |
f4d7e40a | 1917 | struct bpf_func_state *cur; /* state of the current function */ |
638f5b90 | 1918 | int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err; |
b5dc0163 | 1919 | u32 dst_reg = env->prog->insnsi[insn_idx].dst_reg; |
f7cf25b2 | 1920 | struct bpf_reg_state *reg = NULL; |
638f5b90 | 1921 | |
f4d7e40a | 1922 | err = realloc_func_state(state, round_up(slot + 1, BPF_REG_SIZE), |
fd978bf7 | 1923 | state->acquired_refs, true); |
638f5b90 AS |
1924 | if (err) |
1925 | return err; | |
9c399760 AS |
1926 | /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0, |
1927 | * so it's aligned access and [off, off + size) are within stack limits | |
1928 | */ | |
638f5b90 AS |
1929 | if (!env->allow_ptr_leaks && |
1930 | state->stack[spi].slot_type[0] == STACK_SPILL && | |
1931 | size != BPF_REG_SIZE) { | |
1932 | verbose(env, "attempt to corrupt spilled pointer on stack\n"); | |
1933 | return -EACCES; | |
1934 | } | |
17a52670 | 1935 | |
f4d7e40a | 1936 | cur = env->cur_state->frame[env->cur_state->curframe]; |
f7cf25b2 AS |
1937 | if (value_regno >= 0) |
1938 | reg = &cur->regs[value_regno]; | |
17a52670 | 1939 | |
f7cf25b2 AS |
1940 | if (reg && size == BPF_REG_SIZE && register_is_const(reg) && |
1941 | !register_is_null(reg) && env->allow_ptr_leaks) { | |
b5dc0163 AS |
1942 | if (dst_reg != BPF_REG_FP) { |
1943 | /* The backtracking logic can only recognize explicit | |
1944 | * stack slot address like [fp - 8]. Other spill of | |
1945 | * scalar via different register has to be conervative. | |
1946 | * Backtrack from here and mark all registers as precise | |
1947 | * that contributed into 'reg' being a constant. | |
1948 | */ | |
1949 | err = mark_chain_precision(env, value_regno); | |
1950 | if (err) | |
1951 | return err; | |
1952 | } | |
f7cf25b2 AS |
1953 | save_register_state(state, spi, reg); |
1954 | } else if (reg && is_spillable_regtype(reg->type)) { | |
17a52670 | 1955 | /* register containing pointer is being spilled into stack */ |
9c399760 | 1956 | if (size != BPF_REG_SIZE) { |
f7cf25b2 | 1957 | verbose_linfo(env, insn_idx, "; "); |
61bd5218 | 1958 | verbose(env, "invalid size of register spill\n"); |
17a52670 AS |
1959 | return -EACCES; |
1960 | } | |
1961 | ||
f7cf25b2 | 1962 | if (state != cur && reg->type == PTR_TO_STACK) { |
f4d7e40a AS |
1963 | verbose(env, "cannot spill pointers to stack into stack frame of the caller\n"); |
1964 | return -EINVAL; | |
1965 | } | |
1966 | ||
f7cf25b2 AS |
1967 | if (!env->allow_ptr_leaks) { |
1968 | bool sanitize = false; | |
17a52670 | 1969 | |
f7cf25b2 AS |
1970 | if (state->stack[spi].slot_type[0] == STACK_SPILL && |
1971 | register_is_const(&state->stack[spi].spilled_ptr)) | |
1972 | sanitize = true; | |
1973 | for (i = 0; i < BPF_REG_SIZE; i++) | |
1974 | if (state->stack[spi].slot_type[i] == STACK_MISC) { | |
1975 | sanitize = true; | |
1976 | break; | |
1977 | } | |
1978 | if (sanitize) { | |
af86ca4e AS |
1979 | int *poff = &env->insn_aux_data[insn_idx].sanitize_stack_off; |
1980 | int soff = (-spi - 1) * BPF_REG_SIZE; | |
1981 | ||
1982 | /* detected reuse of integer stack slot with a pointer | |
1983 | * which means either llvm is reusing stack slot or | |
1984 | * an attacker is trying to exploit CVE-2018-3639 | |
1985 | * (speculative store bypass) | |
1986 | * Have to sanitize that slot with preemptive | |
1987 | * store of zero. | |
1988 | */ | |
1989 | if (*poff && *poff != soff) { | |
1990 | /* disallow programs where single insn stores | |
1991 | * into two different stack slots, since verifier | |
1992 | * cannot sanitize them | |
1993 | */ | |
1994 | verbose(env, | |
1995 | "insn %d cannot access two stack slots fp%d and fp%d", | |
1996 | insn_idx, *poff, soff); | |
1997 | return -EINVAL; | |
1998 | } | |
1999 | *poff = soff; | |
2000 | } | |
af86ca4e | 2001 | } |
f7cf25b2 | 2002 | save_register_state(state, spi, reg); |
9c399760 | 2003 | } else { |
cc2b14d5 AS |
2004 | u8 type = STACK_MISC; |
2005 | ||
679c782d EC |
2006 | /* regular write of data into stack destroys any spilled ptr */ |
2007 | state->stack[spi].spilled_ptr.type = NOT_INIT; | |
0bae2d4d JW |
2008 | /* Mark slots as STACK_MISC if they belonged to spilled ptr. */ |
2009 | if (state->stack[spi].slot_type[0] == STACK_SPILL) | |
2010 | for (i = 0; i < BPF_REG_SIZE; i++) | |
2011 | state->stack[spi].slot_type[i] = STACK_MISC; | |
9c399760 | 2012 | |
cc2b14d5 AS |
2013 | /* only mark the slot as written if all 8 bytes were written |
2014 | * otherwise read propagation may incorrectly stop too soon | |
2015 | * when stack slots are partially written. | |
2016 | * This heuristic means that read propagation will be | |
2017 | * conservative, since it will add reg_live_read marks | |
2018 | * to stack slots all the way to first state when programs | |
2019 | * writes+reads less than 8 bytes | |
2020 | */ | |
2021 | if (size == BPF_REG_SIZE) | |
2022 | state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN; | |
2023 | ||
2024 | /* when we zero initialize stack slots mark them as such */ | |
b5dc0163 AS |
2025 | if (reg && register_is_null(reg)) { |
2026 | /* backtracking doesn't work for STACK_ZERO yet. */ | |
2027 | err = mark_chain_precision(env, value_regno); | |
2028 | if (err) | |
2029 | return err; | |
cc2b14d5 | 2030 | type = STACK_ZERO; |
b5dc0163 | 2031 | } |
cc2b14d5 | 2032 | |
0bae2d4d | 2033 | /* Mark slots affected by this stack write. */ |
9c399760 | 2034 | for (i = 0; i < size; i++) |
638f5b90 | 2035 | state->stack[spi].slot_type[(slot - i) % BPF_REG_SIZE] = |
cc2b14d5 | 2036 | type; |
17a52670 AS |
2037 | } |
2038 | return 0; | |
2039 | } | |
2040 | ||
61bd5218 | 2041 | static int check_stack_read(struct bpf_verifier_env *env, |
f4d7e40a AS |
2042 | struct bpf_func_state *reg_state /* func where register points to */, |
2043 | int off, int size, int value_regno) | |
17a52670 | 2044 | { |
f4d7e40a AS |
2045 | struct bpf_verifier_state *vstate = env->cur_state; |
2046 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
638f5b90 | 2047 | int i, slot = -off - 1, spi = slot / BPF_REG_SIZE; |
f7cf25b2 | 2048 | struct bpf_reg_state *reg; |
638f5b90 | 2049 | u8 *stype; |
17a52670 | 2050 | |
f4d7e40a | 2051 | if (reg_state->allocated_stack <= slot) { |
638f5b90 AS |
2052 | verbose(env, "invalid read from stack off %d+0 size %d\n", |
2053 | off, size); | |
2054 | return -EACCES; | |
2055 | } | |
f4d7e40a | 2056 | stype = reg_state->stack[spi].slot_type; |
f7cf25b2 | 2057 | reg = ®_state->stack[spi].spilled_ptr; |
17a52670 | 2058 | |
638f5b90 | 2059 | if (stype[0] == STACK_SPILL) { |
9c399760 | 2060 | if (size != BPF_REG_SIZE) { |
f7cf25b2 AS |
2061 | if (reg->type != SCALAR_VALUE) { |
2062 | verbose_linfo(env, env->insn_idx, "; "); | |
2063 | verbose(env, "invalid size of register fill\n"); | |
2064 | return -EACCES; | |
2065 | } | |
2066 | if (value_regno >= 0) { | |
2067 | mark_reg_unknown(env, state->regs, value_regno); | |
2068 | state->regs[value_regno].live |= REG_LIVE_WRITTEN; | |
2069 | } | |
2070 | mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64); | |
2071 | return 0; | |
17a52670 | 2072 | } |
9c399760 | 2073 | for (i = 1; i < BPF_REG_SIZE; i++) { |
638f5b90 | 2074 | if (stype[(slot - i) % BPF_REG_SIZE] != STACK_SPILL) { |
61bd5218 | 2075 | verbose(env, "corrupted spill memory\n"); |
17a52670 AS |
2076 | return -EACCES; |
2077 | } | |
2078 | } | |
2079 | ||
dc503a8a | 2080 | if (value_regno >= 0) { |
17a52670 | 2081 | /* restore register state from stack */ |
f7cf25b2 | 2082 | state->regs[value_regno] = *reg; |
2f18f62e AS |
2083 | /* mark reg as written since spilled pointer state likely |
2084 | * has its liveness marks cleared by is_state_visited() | |
2085 | * which resets stack/reg liveness for state transitions | |
2086 | */ | |
2087 | state->regs[value_regno].live |= REG_LIVE_WRITTEN; | |
dc503a8a | 2088 | } |
f7cf25b2 | 2089 | mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64); |
17a52670 | 2090 | } else { |
cc2b14d5 AS |
2091 | int zeros = 0; |
2092 | ||
17a52670 | 2093 | for (i = 0; i < size; i++) { |
cc2b14d5 AS |
2094 | if (stype[(slot - i) % BPF_REG_SIZE] == STACK_MISC) |
2095 | continue; | |
2096 | if (stype[(slot - i) % BPF_REG_SIZE] == STACK_ZERO) { | |
2097 | zeros++; | |
2098 | continue; | |
17a52670 | 2099 | } |
cc2b14d5 AS |
2100 | verbose(env, "invalid read from stack off %d+%d size %d\n", |
2101 | off, i, size); | |
2102 | return -EACCES; | |
2103 | } | |
f7cf25b2 | 2104 | mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64); |
cc2b14d5 AS |
2105 | if (value_regno >= 0) { |
2106 | if (zeros == size) { | |
2107 | /* any size read into register is zero extended, | |
2108 | * so the whole register == const_zero | |
2109 | */ | |
2110 | __mark_reg_const_zero(&state->regs[value_regno]); | |
b5dc0163 AS |
2111 | /* backtracking doesn't support STACK_ZERO yet, |
2112 | * so mark it precise here, so that later | |
2113 | * backtracking can stop here. | |
2114 | * Backtracking may not need this if this register | |
2115 | * doesn't participate in pointer adjustment. | |
2116 | * Forward propagation of precise flag is not | |
2117 | * necessary either. This mark is only to stop | |
2118 | * backtracking. Any register that contributed | |
2119 | * to const 0 was marked precise before spill. | |
2120 | */ | |
2121 | state->regs[value_regno].precise = true; | |
cc2b14d5 AS |
2122 | } else { |
2123 | /* have read misc data from the stack */ | |
2124 | mark_reg_unknown(env, state->regs, value_regno); | |
2125 | } | |
2126 | state->regs[value_regno].live |= REG_LIVE_WRITTEN; | |
17a52670 | 2127 | } |
17a52670 | 2128 | } |
f7cf25b2 | 2129 | return 0; |
17a52670 AS |
2130 | } |
2131 | ||
e4298d25 DB |
2132 | static int check_stack_access(struct bpf_verifier_env *env, |
2133 | const struct bpf_reg_state *reg, | |
2134 | int off, int size) | |
2135 | { | |
2136 | /* Stack accesses must be at a fixed offset, so that we | |
2137 | * can determine what type of data were returned. See | |
2138 | * check_stack_read(). | |
2139 | */ | |
2140 | if (!tnum_is_const(reg->var_off)) { | |
2141 | char tn_buf[48]; | |
2142 | ||
2143 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
1fbd20f8 | 2144 | verbose(env, "variable stack access var_off=%s off=%d size=%d\n", |
e4298d25 DB |
2145 | tn_buf, off, size); |
2146 | return -EACCES; | |
2147 | } | |
2148 | ||
2149 | if (off >= 0 || off < -MAX_BPF_STACK) { | |
2150 | verbose(env, "invalid stack off=%d size=%d\n", off, size); | |
2151 | return -EACCES; | |
2152 | } | |
2153 | ||
2154 | return 0; | |
2155 | } | |
2156 | ||
591fe988 DB |
2157 | static int check_map_access_type(struct bpf_verifier_env *env, u32 regno, |
2158 | int off, int size, enum bpf_access_type type) | |
2159 | { | |
2160 | struct bpf_reg_state *regs = cur_regs(env); | |
2161 | struct bpf_map *map = regs[regno].map_ptr; | |
2162 | u32 cap = bpf_map_flags_to_cap(map); | |
2163 | ||
2164 | if (type == BPF_WRITE && !(cap & BPF_MAP_CAN_WRITE)) { | |
2165 | verbose(env, "write into map forbidden, value_size=%d off=%d size=%d\n", | |
2166 | map->value_size, off, size); | |
2167 | return -EACCES; | |
2168 | } | |
2169 | ||
2170 | if (type == BPF_READ && !(cap & BPF_MAP_CAN_READ)) { | |
2171 | verbose(env, "read from map forbidden, value_size=%d off=%d size=%d\n", | |
2172 | map->value_size, off, size); | |
2173 | return -EACCES; | |
2174 | } | |
2175 | ||
2176 | return 0; | |
2177 | } | |
2178 | ||
17a52670 | 2179 | /* check read/write into map element returned by bpf_map_lookup_elem() */ |
f1174f77 | 2180 | static int __check_map_access(struct bpf_verifier_env *env, u32 regno, int off, |
9fd29c08 | 2181 | int size, bool zero_size_allowed) |
17a52670 | 2182 | { |
638f5b90 AS |
2183 | struct bpf_reg_state *regs = cur_regs(env); |
2184 | struct bpf_map *map = regs[regno].map_ptr; | |
17a52670 | 2185 | |
9fd29c08 YS |
2186 | if (off < 0 || size < 0 || (size == 0 && !zero_size_allowed) || |
2187 | off + size > map->value_size) { | |
61bd5218 | 2188 | verbose(env, "invalid access to map value, value_size=%d off=%d size=%d\n", |
17a52670 AS |
2189 | map->value_size, off, size); |
2190 | return -EACCES; | |
2191 | } | |
2192 | return 0; | |
2193 | } | |
2194 | ||
f1174f77 EC |
2195 | /* check read/write into a map element with possible variable offset */ |
2196 | static int check_map_access(struct bpf_verifier_env *env, u32 regno, | |
9fd29c08 | 2197 | int off, int size, bool zero_size_allowed) |
dbcfe5f7 | 2198 | { |
f4d7e40a AS |
2199 | struct bpf_verifier_state *vstate = env->cur_state; |
2200 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
dbcfe5f7 GB |
2201 | struct bpf_reg_state *reg = &state->regs[regno]; |
2202 | int err; | |
2203 | ||
f1174f77 EC |
2204 | /* We may have adjusted the register to this map value, so we |
2205 | * need to try adding each of min_value and max_value to off | |
2206 | * to make sure our theoretical access will be safe. | |
dbcfe5f7 | 2207 | */ |
06ee7115 | 2208 | if (env->log.level & BPF_LOG_LEVEL) |
61bd5218 | 2209 | print_verifier_state(env, state); |
b7137c4e | 2210 | |
dbcfe5f7 GB |
2211 | /* The minimum value is only important with signed |
2212 | * comparisons where we can't assume the floor of a | |
2213 | * value is 0. If we are using signed variables for our | |
2214 | * index'es we need to make sure that whatever we use | |
2215 | * will have a set floor within our range. | |
2216 | */ | |
b7137c4e DB |
2217 | if (reg->smin_value < 0 && |
2218 | (reg->smin_value == S64_MIN || | |
2219 | (off + reg->smin_value != (s64)(s32)(off + reg->smin_value)) || | |
2220 | reg->smin_value + off < 0)) { | |
61bd5218 | 2221 | verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", |
dbcfe5f7 GB |
2222 | regno); |
2223 | return -EACCES; | |
2224 | } | |
9fd29c08 YS |
2225 | err = __check_map_access(env, regno, reg->smin_value + off, size, |
2226 | zero_size_allowed); | |
dbcfe5f7 | 2227 | if (err) { |
61bd5218 JK |
2228 | verbose(env, "R%d min value is outside of the array range\n", |
2229 | regno); | |
dbcfe5f7 GB |
2230 | return err; |
2231 | } | |
2232 | ||
b03c9f9f EC |
2233 | /* If we haven't set a max value then we need to bail since we can't be |
2234 | * sure we won't do bad things. | |
2235 | * If reg->umax_value + off could overflow, treat that as unbounded too. | |
dbcfe5f7 | 2236 | */ |
b03c9f9f | 2237 | if (reg->umax_value >= BPF_MAX_VAR_OFF) { |
61bd5218 | 2238 | verbose(env, "R%d unbounded memory access, make sure to bounds check any array access into a map\n", |
dbcfe5f7 GB |
2239 | regno); |
2240 | return -EACCES; | |
2241 | } | |
9fd29c08 YS |
2242 | err = __check_map_access(env, regno, reg->umax_value + off, size, |
2243 | zero_size_allowed); | |
f1174f77 | 2244 | if (err) |
61bd5218 JK |
2245 | verbose(env, "R%d max value is outside of the array range\n", |
2246 | regno); | |
d83525ca AS |
2247 | |
2248 | if (map_value_has_spin_lock(reg->map_ptr)) { | |
2249 | u32 lock = reg->map_ptr->spin_lock_off; | |
2250 | ||
2251 | /* if any part of struct bpf_spin_lock can be touched by | |
2252 | * load/store reject this program. | |
2253 | * To check that [x1, x2) overlaps with [y1, y2) | |
2254 | * it is sufficient to check x1 < y2 && y1 < x2. | |
2255 | */ | |
2256 | if (reg->smin_value + off < lock + sizeof(struct bpf_spin_lock) && | |
2257 | lock < reg->umax_value + off + size) { | |
2258 | verbose(env, "bpf_spin_lock cannot be accessed directly by load/store\n"); | |
2259 | return -EACCES; | |
2260 | } | |
2261 | } | |
f1174f77 | 2262 | return err; |
dbcfe5f7 GB |
2263 | } |
2264 | ||
969bf05e AS |
2265 | #define MAX_PACKET_OFF 0xffff |
2266 | ||
58e2af8b | 2267 | static bool may_access_direct_pkt_data(struct bpf_verifier_env *env, |
3a0af8fd TG |
2268 | const struct bpf_call_arg_meta *meta, |
2269 | enum bpf_access_type t) | |
4acf6c0b | 2270 | { |
36bbef52 | 2271 | switch (env->prog->type) { |
5d66fa7d | 2272 | /* Program types only with direct read access go here! */ |
3a0af8fd TG |
2273 | case BPF_PROG_TYPE_LWT_IN: |
2274 | case BPF_PROG_TYPE_LWT_OUT: | |
004d4b27 | 2275 | case BPF_PROG_TYPE_LWT_SEG6LOCAL: |
2dbb9b9e | 2276 | case BPF_PROG_TYPE_SK_REUSEPORT: |
5d66fa7d | 2277 | case BPF_PROG_TYPE_FLOW_DISSECTOR: |
d5563d36 | 2278 | case BPF_PROG_TYPE_CGROUP_SKB: |
3a0af8fd TG |
2279 | if (t == BPF_WRITE) |
2280 | return false; | |
7e57fbb2 | 2281 | /* fallthrough */ |
5d66fa7d DB |
2282 | |
2283 | /* Program types with direct read + write access go here! */ | |
36bbef52 DB |
2284 | case BPF_PROG_TYPE_SCHED_CLS: |
2285 | case BPF_PROG_TYPE_SCHED_ACT: | |
4acf6c0b | 2286 | case BPF_PROG_TYPE_XDP: |
3a0af8fd | 2287 | case BPF_PROG_TYPE_LWT_XMIT: |
8a31db56 | 2288 | case BPF_PROG_TYPE_SK_SKB: |
4f738adb | 2289 | case BPF_PROG_TYPE_SK_MSG: |
36bbef52 DB |
2290 | if (meta) |
2291 | return meta->pkt_access; | |
2292 | ||
2293 | env->seen_direct_write = true; | |
4acf6c0b | 2294 | return true; |
0d01da6a SF |
2295 | |
2296 | case BPF_PROG_TYPE_CGROUP_SOCKOPT: | |
2297 | if (t == BPF_WRITE) | |
2298 | env->seen_direct_write = true; | |
2299 | ||
2300 | return true; | |
2301 | ||
4acf6c0b BB |
2302 | default: |
2303 | return false; | |
2304 | } | |
2305 | } | |
2306 | ||
f1174f77 | 2307 | static int __check_packet_access(struct bpf_verifier_env *env, u32 regno, |
9fd29c08 | 2308 | int off, int size, bool zero_size_allowed) |
969bf05e | 2309 | { |
638f5b90 | 2310 | struct bpf_reg_state *regs = cur_regs(env); |
58e2af8b | 2311 | struct bpf_reg_state *reg = ®s[regno]; |
969bf05e | 2312 | |
9fd29c08 YS |
2313 | if (off < 0 || size < 0 || (size == 0 && !zero_size_allowed) || |
2314 | (u64)off + size > reg->range) { | |
61bd5218 | 2315 | verbose(env, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n", |
d91b28ed | 2316 | off, size, regno, reg->id, reg->off, reg->range); |
969bf05e AS |
2317 | return -EACCES; |
2318 | } | |
2319 | return 0; | |
2320 | } | |
2321 | ||
f1174f77 | 2322 | static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, |
9fd29c08 | 2323 | int size, bool zero_size_allowed) |
f1174f77 | 2324 | { |
638f5b90 | 2325 | struct bpf_reg_state *regs = cur_regs(env); |
f1174f77 EC |
2326 | struct bpf_reg_state *reg = ®s[regno]; |
2327 | int err; | |
2328 | ||
2329 | /* We may have added a variable offset to the packet pointer; but any | |
2330 | * reg->range we have comes after that. We are only checking the fixed | |
2331 | * offset. | |
2332 | */ | |
2333 | ||
2334 | /* We don't allow negative numbers, because we aren't tracking enough | |
2335 | * detail to prove they're safe. | |
2336 | */ | |
b03c9f9f | 2337 | if (reg->smin_value < 0) { |
61bd5218 | 2338 | verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", |
f1174f77 EC |
2339 | regno); |
2340 | return -EACCES; | |
2341 | } | |
9fd29c08 | 2342 | err = __check_packet_access(env, regno, off, size, zero_size_allowed); |
f1174f77 | 2343 | if (err) { |
61bd5218 | 2344 | verbose(env, "R%d offset is outside of the packet\n", regno); |
f1174f77 EC |
2345 | return err; |
2346 | } | |
e647815a JW |
2347 | |
2348 | /* __check_packet_access has made sure "off + size - 1" is within u16. | |
2349 | * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff, | |
2350 | * otherwise find_good_pkt_pointers would have refused to set range info | |
2351 | * that __check_packet_access would have rejected this pkt access. | |
2352 | * Therefore, "off + reg->umax_value + size - 1" won't overflow u32. | |
2353 | */ | |
2354 | env->prog->aux->max_pkt_offset = | |
2355 | max_t(u32, env->prog->aux->max_pkt_offset, | |
2356 | off + reg->umax_value + size - 1); | |
2357 | ||
f1174f77 EC |
2358 | return err; |
2359 | } | |
2360 | ||
2361 | /* check access to 'struct bpf_context' fields. Supports fixed offsets only */ | |
31fd8581 | 2362 | static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size, |
9e15db66 AS |
2363 | enum bpf_access_type t, enum bpf_reg_type *reg_type, |
2364 | u32 *btf_id) | |
17a52670 | 2365 | { |
f96da094 DB |
2366 | struct bpf_insn_access_aux info = { |
2367 | .reg_type = *reg_type, | |
9e15db66 | 2368 | .log = &env->log, |
f96da094 | 2369 | }; |
31fd8581 | 2370 | |
4f9218aa | 2371 | if (env->ops->is_valid_access && |
5e43f899 | 2372 | env->ops->is_valid_access(off, size, t, env->prog, &info)) { |
f96da094 DB |
2373 | /* A non zero info.ctx_field_size indicates that this field is a |
2374 | * candidate for later verifier transformation to load the whole | |
2375 | * field and then apply a mask when accessed with a narrower | |
2376 | * access than actual ctx access size. A zero info.ctx_field_size | |
2377 | * will only allow for whole field access and rejects any other | |
2378 | * type of narrower access. | |
31fd8581 | 2379 | */ |
23994631 | 2380 | *reg_type = info.reg_type; |
31fd8581 | 2381 | |
9e15db66 AS |
2382 | if (*reg_type == PTR_TO_BTF_ID) |
2383 | *btf_id = info.btf_id; | |
2384 | else | |
2385 | env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size; | |
32bbe007 AS |
2386 | /* remember the offset of last byte accessed in ctx */ |
2387 | if (env->prog->aux->max_ctx_offset < off + size) | |
2388 | env->prog->aux->max_ctx_offset = off + size; | |
17a52670 | 2389 | return 0; |
32bbe007 | 2390 | } |
17a52670 | 2391 | |
61bd5218 | 2392 | verbose(env, "invalid bpf_context access off=%d size=%d\n", off, size); |
17a52670 AS |
2393 | return -EACCES; |
2394 | } | |
2395 | ||
d58e468b PP |
2396 | static int check_flow_keys_access(struct bpf_verifier_env *env, int off, |
2397 | int size) | |
2398 | { | |
2399 | if (size < 0 || off < 0 || | |
2400 | (u64)off + size > sizeof(struct bpf_flow_keys)) { | |
2401 | verbose(env, "invalid access to flow keys off=%d size=%d\n", | |
2402 | off, size); | |
2403 | return -EACCES; | |
2404 | } | |
2405 | return 0; | |
2406 | } | |
2407 | ||
5f456649 MKL |
2408 | static int check_sock_access(struct bpf_verifier_env *env, int insn_idx, |
2409 | u32 regno, int off, int size, | |
2410 | enum bpf_access_type t) | |
c64b7983 JS |
2411 | { |
2412 | struct bpf_reg_state *regs = cur_regs(env); | |
2413 | struct bpf_reg_state *reg = ®s[regno]; | |
5f456649 | 2414 | struct bpf_insn_access_aux info = {}; |
46f8bc92 | 2415 | bool valid; |
c64b7983 JS |
2416 | |
2417 | if (reg->smin_value < 0) { | |
2418 | verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", | |
2419 | regno); | |
2420 | return -EACCES; | |
2421 | } | |
2422 | ||
46f8bc92 MKL |
2423 | switch (reg->type) { |
2424 | case PTR_TO_SOCK_COMMON: | |
2425 | valid = bpf_sock_common_is_valid_access(off, size, t, &info); | |
2426 | break; | |
2427 | case PTR_TO_SOCKET: | |
2428 | valid = bpf_sock_is_valid_access(off, size, t, &info); | |
2429 | break; | |
655a51e5 MKL |
2430 | case PTR_TO_TCP_SOCK: |
2431 | valid = bpf_tcp_sock_is_valid_access(off, size, t, &info); | |
2432 | break; | |
fada7fdc JL |
2433 | case PTR_TO_XDP_SOCK: |
2434 | valid = bpf_xdp_sock_is_valid_access(off, size, t, &info); | |
2435 | break; | |
46f8bc92 MKL |
2436 | default: |
2437 | valid = false; | |
c64b7983 JS |
2438 | } |
2439 | ||
5f456649 | 2440 | |
46f8bc92 MKL |
2441 | if (valid) { |
2442 | env->insn_aux_data[insn_idx].ctx_field_size = | |
2443 | info.ctx_field_size; | |
2444 | return 0; | |
2445 | } | |
2446 | ||
2447 | verbose(env, "R%d invalid %s access off=%d size=%d\n", | |
2448 | regno, reg_type_str[reg->type], off, size); | |
2449 | ||
2450 | return -EACCES; | |
c64b7983 JS |
2451 | } |
2452 | ||
4cabc5b1 DB |
2453 | static bool __is_pointer_value(bool allow_ptr_leaks, |
2454 | const struct bpf_reg_state *reg) | |
1be7f75d | 2455 | { |
4cabc5b1 | 2456 | if (allow_ptr_leaks) |
1be7f75d AS |
2457 | return false; |
2458 | ||
f1174f77 | 2459 | return reg->type != SCALAR_VALUE; |
1be7f75d AS |
2460 | } |
2461 | ||
2a159c6f DB |
2462 | static struct bpf_reg_state *reg_state(struct bpf_verifier_env *env, int regno) |
2463 | { | |
2464 | return cur_regs(env) + regno; | |
2465 | } | |
2466 | ||
4cabc5b1 DB |
2467 | static bool is_pointer_value(struct bpf_verifier_env *env, int regno) |
2468 | { | |
2a159c6f | 2469 | return __is_pointer_value(env->allow_ptr_leaks, reg_state(env, regno)); |
4cabc5b1 DB |
2470 | } |
2471 | ||
f37a8cb8 DB |
2472 | static bool is_ctx_reg(struct bpf_verifier_env *env, int regno) |
2473 | { | |
2a159c6f | 2474 | const struct bpf_reg_state *reg = reg_state(env, regno); |
f37a8cb8 | 2475 | |
46f8bc92 MKL |
2476 | return reg->type == PTR_TO_CTX; |
2477 | } | |
2478 | ||
2479 | static bool is_sk_reg(struct bpf_verifier_env *env, int regno) | |
2480 | { | |
2481 | const struct bpf_reg_state *reg = reg_state(env, regno); | |
2482 | ||
2483 | return type_is_sk_pointer(reg->type); | |
f37a8cb8 DB |
2484 | } |
2485 | ||
ca369602 DB |
2486 | static bool is_pkt_reg(struct bpf_verifier_env *env, int regno) |
2487 | { | |
2a159c6f | 2488 | const struct bpf_reg_state *reg = reg_state(env, regno); |
ca369602 DB |
2489 | |
2490 | return type_is_pkt_pointer(reg->type); | |
2491 | } | |
2492 | ||
4b5defde DB |
2493 | static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno) |
2494 | { | |
2495 | const struct bpf_reg_state *reg = reg_state(env, regno); | |
2496 | ||
2497 | /* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */ | |
2498 | return reg->type == PTR_TO_FLOW_KEYS; | |
2499 | } | |
2500 | ||
61bd5218 JK |
2501 | static int check_pkt_ptr_alignment(struct bpf_verifier_env *env, |
2502 | const struct bpf_reg_state *reg, | |
d1174416 | 2503 | int off, int size, bool strict) |
969bf05e | 2504 | { |
f1174f77 | 2505 | struct tnum reg_off; |
e07b98d9 | 2506 | int ip_align; |
d1174416 DM |
2507 | |
2508 | /* Byte size accesses are always allowed. */ | |
2509 | if (!strict || size == 1) | |
2510 | return 0; | |
2511 | ||
e4eda884 DM |
2512 | /* For platforms that do not have a Kconfig enabling |
2513 | * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of | |
2514 | * NET_IP_ALIGN is universally set to '2'. And on platforms | |
2515 | * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get | |
2516 | * to this code only in strict mode where we want to emulate | |
2517 | * the NET_IP_ALIGN==2 checking. Therefore use an | |
2518 | * unconditional IP align value of '2'. | |
e07b98d9 | 2519 | */ |
e4eda884 | 2520 | ip_align = 2; |
f1174f77 EC |
2521 | |
2522 | reg_off = tnum_add(reg->var_off, tnum_const(ip_align + reg->off + off)); | |
2523 | if (!tnum_is_aligned(reg_off, size)) { | |
2524 | char tn_buf[48]; | |
2525 | ||
2526 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
61bd5218 JK |
2527 | verbose(env, |
2528 | "misaligned packet access off %d+%s+%d+%d size %d\n", | |
f1174f77 | 2529 | ip_align, tn_buf, reg->off, off, size); |
969bf05e AS |
2530 | return -EACCES; |
2531 | } | |
79adffcd | 2532 | |
969bf05e AS |
2533 | return 0; |
2534 | } | |
2535 | ||
61bd5218 JK |
2536 | static int check_generic_ptr_alignment(struct bpf_verifier_env *env, |
2537 | const struct bpf_reg_state *reg, | |
f1174f77 EC |
2538 | const char *pointer_desc, |
2539 | int off, int size, bool strict) | |
79adffcd | 2540 | { |
f1174f77 EC |
2541 | struct tnum reg_off; |
2542 | ||
2543 | /* Byte size accesses are always allowed. */ | |
2544 | if (!strict || size == 1) | |
2545 | return 0; | |
2546 | ||
2547 | reg_off = tnum_add(reg->var_off, tnum_const(reg->off + off)); | |
2548 | if (!tnum_is_aligned(reg_off, size)) { | |
2549 | char tn_buf[48]; | |
2550 | ||
2551 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
61bd5218 | 2552 | verbose(env, "misaligned %saccess off %s+%d+%d size %d\n", |
f1174f77 | 2553 | pointer_desc, tn_buf, reg->off, off, size); |
79adffcd DB |
2554 | return -EACCES; |
2555 | } | |
2556 | ||
969bf05e AS |
2557 | return 0; |
2558 | } | |
2559 | ||
e07b98d9 | 2560 | static int check_ptr_alignment(struct bpf_verifier_env *env, |
ca369602 DB |
2561 | const struct bpf_reg_state *reg, int off, |
2562 | int size, bool strict_alignment_once) | |
79adffcd | 2563 | { |
ca369602 | 2564 | bool strict = env->strict_alignment || strict_alignment_once; |
f1174f77 | 2565 | const char *pointer_desc = ""; |
d1174416 | 2566 | |
79adffcd DB |
2567 | switch (reg->type) { |
2568 | case PTR_TO_PACKET: | |
de8f3a83 DB |
2569 | case PTR_TO_PACKET_META: |
2570 | /* Special case, because of NET_IP_ALIGN. Given metadata sits | |
2571 | * right in front, treat it the very same way. | |
2572 | */ | |
61bd5218 | 2573 | return check_pkt_ptr_alignment(env, reg, off, size, strict); |
d58e468b PP |
2574 | case PTR_TO_FLOW_KEYS: |
2575 | pointer_desc = "flow keys "; | |
2576 | break; | |
f1174f77 EC |
2577 | case PTR_TO_MAP_VALUE: |
2578 | pointer_desc = "value "; | |
2579 | break; | |
2580 | case PTR_TO_CTX: | |
2581 | pointer_desc = "context "; | |
2582 | break; | |
2583 | case PTR_TO_STACK: | |
2584 | pointer_desc = "stack "; | |
a5ec6ae1 JH |
2585 | /* The stack spill tracking logic in check_stack_write() |
2586 | * and check_stack_read() relies on stack accesses being | |
2587 | * aligned. | |
2588 | */ | |
2589 | strict = true; | |
f1174f77 | 2590 | break; |
c64b7983 JS |
2591 | case PTR_TO_SOCKET: |
2592 | pointer_desc = "sock "; | |
2593 | break; | |
46f8bc92 MKL |
2594 | case PTR_TO_SOCK_COMMON: |
2595 | pointer_desc = "sock_common "; | |
2596 | break; | |
655a51e5 MKL |
2597 | case PTR_TO_TCP_SOCK: |
2598 | pointer_desc = "tcp_sock "; | |
2599 | break; | |
fada7fdc JL |
2600 | case PTR_TO_XDP_SOCK: |
2601 | pointer_desc = "xdp_sock "; | |
2602 | break; | |
79adffcd | 2603 | default: |
f1174f77 | 2604 | break; |
79adffcd | 2605 | } |
61bd5218 JK |
2606 | return check_generic_ptr_alignment(env, reg, pointer_desc, off, size, |
2607 | strict); | |
79adffcd DB |
2608 | } |
2609 | ||
f4d7e40a AS |
2610 | static int update_stack_depth(struct bpf_verifier_env *env, |
2611 | const struct bpf_func_state *func, | |
2612 | int off) | |
2613 | { | |
9c8105bd | 2614 | u16 stack = env->subprog_info[func->subprogno].stack_depth; |
f4d7e40a AS |
2615 | |
2616 | if (stack >= -off) | |
2617 | return 0; | |
2618 | ||
2619 | /* update known max for given subprogram */ | |
9c8105bd | 2620 | env->subprog_info[func->subprogno].stack_depth = -off; |
70a87ffe AS |
2621 | return 0; |
2622 | } | |
f4d7e40a | 2623 | |
70a87ffe AS |
2624 | /* starting from main bpf function walk all instructions of the function |
2625 | * and recursively walk all callees that given function can call. | |
2626 | * Ignore jump and exit insns. | |
2627 | * Since recursion is prevented by check_cfg() this algorithm | |
2628 | * only needs a local stack of MAX_CALL_FRAMES to remember callsites | |
2629 | */ | |
2630 | static int check_max_stack_depth(struct bpf_verifier_env *env) | |
2631 | { | |
9c8105bd JW |
2632 | int depth = 0, frame = 0, idx = 0, i = 0, subprog_end; |
2633 | struct bpf_subprog_info *subprog = env->subprog_info; | |
70a87ffe | 2634 | struct bpf_insn *insn = env->prog->insnsi; |
70a87ffe AS |
2635 | int ret_insn[MAX_CALL_FRAMES]; |
2636 | int ret_prog[MAX_CALL_FRAMES]; | |
f4d7e40a | 2637 | |
70a87ffe AS |
2638 | process_func: |
2639 | /* round up to 32-bytes, since this is granularity | |
2640 | * of interpreter stack size | |
2641 | */ | |
9c8105bd | 2642 | depth += round_up(max_t(u32, subprog[idx].stack_depth, 1), 32); |
70a87ffe | 2643 | if (depth > MAX_BPF_STACK) { |
f4d7e40a | 2644 | verbose(env, "combined stack size of %d calls is %d. Too large\n", |
70a87ffe | 2645 | frame + 1, depth); |
f4d7e40a AS |
2646 | return -EACCES; |
2647 | } | |
70a87ffe | 2648 | continue_func: |
4cb3d99c | 2649 | subprog_end = subprog[idx + 1].start; |
70a87ffe AS |
2650 | for (; i < subprog_end; i++) { |
2651 | if (insn[i].code != (BPF_JMP | BPF_CALL)) | |
2652 | continue; | |
2653 | if (insn[i].src_reg != BPF_PSEUDO_CALL) | |
2654 | continue; | |
2655 | /* remember insn and function to return to */ | |
2656 | ret_insn[frame] = i + 1; | |
9c8105bd | 2657 | ret_prog[frame] = idx; |
70a87ffe AS |
2658 | |
2659 | /* find the callee */ | |
2660 | i = i + insn[i].imm + 1; | |
9c8105bd JW |
2661 | idx = find_subprog(env, i); |
2662 | if (idx < 0) { | |
70a87ffe AS |
2663 | WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", |
2664 | i); | |
2665 | return -EFAULT; | |
2666 | } | |
70a87ffe AS |
2667 | frame++; |
2668 | if (frame >= MAX_CALL_FRAMES) { | |
927cb781 PC |
2669 | verbose(env, "the call stack of %d frames is too deep !\n", |
2670 | frame); | |
2671 | return -E2BIG; | |
70a87ffe AS |
2672 | } |
2673 | goto process_func; | |
2674 | } | |
2675 | /* end of for() loop means the last insn of the 'subprog' | |
2676 | * was reached. Doesn't matter whether it was JA or EXIT | |
2677 | */ | |
2678 | if (frame == 0) | |
2679 | return 0; | |
9c8105bd | 2680 | depth -= round_up(max_t(u32, subprog[idx].stack_depth, 1), 32); |
70a87ffe AS |
2681 | frame--; |
2682 | i = ret_insn[frame]; | |
9c8105bd | 2683 | idx = ret_prog[frame]; |
70a87ffe | 2684 | goto continue_func; |
f4d7e40a AS |
2685 | } |
2686 | ||
19d28fbd | 2687 | #ifndef CONFIG_BPF_JIT_ALWAYS_ON |
1ea47e01 AS |
2688 | static int get_callee_stack_depth(struct bpf_verifier_env *env, |
2689 | const struct bpf_insn *insn, int idx) | |
2690 | { | |
2691 | int start = idx + insn->imm + 1, subprog; | |
2692 | ||
2693 | subprog = find_subprog(env, start); | |
2694 | if (subprog < 0) { | |
2695 | WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", | |
2696 | start); | |
2697 | return -EFAULT; | |
2698 | } | |
9c8105bd | 2699 | return env->subprog_info[subprog].stack_depth; |
1ea47e01 | 2700 | } |
19d28fbd | 2701 | #endif |
1ea47e01 | 2702 | |
58990d1f DB |
2703 | static int check_ctx_reg(struct bpf_verifier_env *env, |
2704 | const struct bpf_reg_state *reg, int regno) | |
2705 | { | |
2706 | /* Access to ctx or passing it to a helper is only allowed in | |
2707 | * its original, unmodified form. | |
2708 | */ | |
2709 | ||
2710 | if (reg->off) { | |
2711 | verbose(env, "dereference of modified ctx ptr R%d off=%d disallowed\n", | |
2712 | regno, reg->off); | |
2713 | return -EACCES; | |
2714 | } | |
2715 | ||
2716 | if (!tnum_is_const(reg->var_off) || reg->var_off.value) { | |
2717 | char tn_buf[48]; | |
2718 | ||
2719 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
2720 | verbose(env, "variable ctx access var_off=%s disallowed\n", tn_buf); | |
2721 | return -EACCES; | |
2722 | } | |
2723 | ||
2724 | return 0; | |
2725 | } | |
2726 | ||
9df1c28b MM |
2727 | static int check_tp_buffer_access(struct bpf_verifier_env *env, |
2728 | const struct bpf_reg_state *reg, | |
2729 | int regno, int off, int size) | |
2730 | { | |
2731 | if (off < 0) { | |
2732 | verbose(env, | |
2733 | "R%d invalid tracepoint buffer access: off=%d, size=%d", | |
2734 | regno, off, size); | |
2735 | return -EACCES; | |
2736 | } | |
2737 | if (!tnum_is_const(reg->var_off) || reg->var_off.value) { | |
2738 | char tn_buf[48]; | |
2739 | ||
2740 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
2741 | verbose(env, | |
2742 | "R%d invalid variable buffer offset: off=%d, var_off=%s", | |
2743 | regno, off, tn_buf); | |
2744 | return -EACCES; | |
2745 | } | |
2746 | if (off + size > env->prog->aux->max_tp_access) | |
2747 | env->prog->aux->max_tp_access = off + size; | |
2748 | ||
2749 | return 0; | |
2750 | } | |
2751 | ||
2752 | ||
0c17d1d2 JH |
2753 | /* truncate register to smaller size (in bytes) |
2754 | * must be called with size < BPF_REG_SIZE | |
2755 | */ | |
2756 | static void coerce_reg_to_size(struct bpf_reg_state *reg, int size) | |
2757 | { | |
2758 | u64 mask; | |
2759 | ||
2760 | /* clear high bits in bit representation */ | |
2761 | reg->var_off = tnum_cast(reg->var_off, size); | |
2762 | ||
2763 | /* fix arithmetic bounds */ | |
2764 | mask = ((u64)1 << (size * 8)) - 1; | |
2765 | if ((reg->umin_value & ~mask) == (reg->umax_value & ~mask)) { | |
2766 | reg->umin_value &= mask; | |
2767 | reg->umax_value &= mask; | |
2768 | } else { | |
2769 | reg->umin_value = 0; | |
2770 | reg->umax_value = mask; | |
2771 | } | |
2772 | reg->smin_value = reg->umin_value; | |
2773 | reg->smax_value = reg->umax_value; | |
2774 | } | |
2775 | ||
a23740ec AN |
2776 | static bool bpf_map_is_rdonly(const struct bpf_map *map) |
2777 | { | |
2778 | return (map->map_flags & BPF_F_RDONLY_PROG) && map->frozen; | |
2779 | } | |
2780 | ||
2781 | static int bpf_map_direct_read(struct bpf_map *map, int off, int size, u64 *val) | |
2782 | { | |
2783 | void *ptr; | |
2784 | u64 addr; | |
2785 | int err; | |
2786 | ||
2787 | err = map->ops->map_direct_value_addr(map, &addr, off); | |
2788 | if (err) | |
2789 | return err; | |
2dedd7d2 | 2790 | ptr = (void *)(long)addr + off; |
a23740ec AN |
2791 | |
2792 | switch (size) { | |
2793 | case sizeof(u8): | |
2794 | *val = (u64)*(u8 *)ptr; | |
2795 | break; | |
2796 | case sizeof(u16): | |
2797 | *val = (u64)*(u16 *)ptr; | |
2798 | break; | |
2799 | case sizeof(u32): | |
2800 | *val = (u64)*(u32 *)ptr; | |
2801 | break; | |
2802 | case sizeof(u64): | |
2803 | *val = *(u64 *)ptr; | |
2804 | break; | |
2805 | default: | |
2806 | return -EINVAL; | |
2807 | } | |
2808 | return 0; | |
2809 | } | |
2810 | ||
9e15db66 AS |
2811 | static int check_ptr_to_btf_access(struct bpf_verifier_env *env, |
2812 | struct bpf_reg_state *regs, | |
2813 | int regno, int off, int size, | |
2814 | enum bpf_access_type atype, | |
2815 | int value_regno) | |
2816 | { | |
2817 | struct bpf_reg_state *reg = regs + regno; | |
2818 | const struct btf_type *t = btf_type_by_id(btf_vmlinux, reg->btf_id); | |
2819 | const char *tname = btf_name_by_offset(btf_vmlinux, t->name_off); | |
2820 | u32 btf_id; | |
2821 | int ret; | |
2822 | ||
2823 | if (atype != BPF_READ) { | |
2824 | verbose(env, "only read is supported\n"); | |
2825 | return -EACCES; | |
2826 | } | |
2827 | ||
2828 | if (off < 0) { | |
2829 | verbose(env, | |
2830 | "R%d is ptr_%s invalid negative access: off=%d\n", | |
2831 | regno, tname, off); | |
2832 | return -EACCES; | |
2833 | } | |
2834 | if (!tnum_is_const(reg->var_off) || reg->var_off.value) { | |
2835 | char tn_buf[48]; | |
2836 | ||
2837 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
2838 | verbose(env, | |
2839 | "R%d is ptr_%s invalid variable offset: off=%d, var_off=%s\n", | |
2840 | regno, tname, off, tn_buf); | |
2841 | return -EACCES; | |
2842 | } | |
2843 | ||
2844 | ret = btf_struct_access(&env->log, t, off, size, atype, &btf_id); | |
2845 | if (ret < 0) | |
2846 | return ret; | |
2847 | ||
2848 | if (ret == SCALAR_VALUE) { | |
2849 | mark_reg_unknown(env, regs, value_regno); | |
2850 | return 0; | |
2851 | } | |
2852 | mark_reg_known_zero(env, regs, value_regno); | |
2853 | regs[value_regno].type = PTR_TO_BTF_ID; | |
2854 | regs[value_regno].btf_id = btf_id; | |
2855 | return 0; | |
2856 | } | |
2857 | ||
17a52670 AS |
2858 | /* check whether memory at (regno + off) is accessible for t = (read | write) |
2859 | * if t==write, value_regno is a register which value is stored into memory | |
2860 | * if t==read, value_regno is a register which will receive the value from memory | |
2861 | * if t==write && value_regno==-1, some unknown value is stored into memory | |
2862 | * if t==read && value_regno==-1, don't care what we read from memory | |
2863 | */ | |
ca369602 DB |
2864 | static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno, |
2865 | int off, int bpf_size, enum bpf_access_type t, | |
2866 | int value_regno, bool strict_alignment_once) | |
17a52670 | 2867 | { |
638f5b90 AS |
2868 | struct bpf_reg_state *regs = cur_regs(env); |
2869 | struct bpf_reg_state *reg = regs + regno; | |
f4d7e40a | 2870 | struct bpf_func_state *state; |
17a52670 AS |
2871 | int size, err = 0; |
2872 | ||
2873 | size = bpf_size_to_bytes(bpf_size); | |
2874 | if (size < 0) | |
2875 | return size; | |
2876 | ||
f1174f77 | 2877 | /* alignment checks will add in reg->off themselves */ |
ca369602 | 2878 | err = check_ptr_alignment(env, reg, off, size, strict_alignment_once); |
969bf05e AS |
2879 | if (err) |
2880 | return err; | |
17a52670 | 2881 | |
f1174f77 EC |
2882 | /* for access checks, reg->off is just part of off */ |
2883 | off += reg->off; | |
2884 | ||
2885 | if (reg->type == PTR_TO_MAP_VALUE) { | |
1be7f75d AS |
2886 | if (t == BPF_WRITE && value_regno >= 0 && |
2887 | is_pointer_value(env, value_regno)) { | |
61bd5218 | 2888 | verbose(env, "R%d leaks addr into map\n", value_regno); |
1be7f75d AS |
2889 | return -EACCES; |
2890 | } | |
591fe988 DB |
2891 | err = check_map_access_type(env, regno, off, size, t); |
2892 | if (err) | |
2893 | return err; | |
9fd29c08 | 2894 | err = check_map_access(env, regno, off, size, false); |
a23740ec AN |
2895 | if (!err && t == BPF_READ && value_regno >= 0) { |
2896 | struct bpf_map *map = reg->map_ptr; | |
2897 | ||
2898 | /* if map is read-only, track its contents as scalars */ | |
2899 | if (tnum_is_const(reg->var_off) && | |
2900 | bpf_map_is_rdonly(map) && | |
2901 | map->ops->map_direct_value_addr) { | |
2902 | int map_off = off + reg->var_off.value; | |
2903 | u64 val = 0; | |
2904 | ||
2905 | err = bpf_map_direct_read(map, map_off, size, | |
2906 | &val); | |
2907 | if (err) | |
2908 | return err; | |
2909 | ||
2910 | regs[value_regno].type = SCALAR_VALUE; | |
2911 | __mark_reg_known(®s[value_regno], val); | |
2912 | } else { | |
2913 | mark_reg_unknown(env, regs, value_regno); | |
2914 | } | |
2915 | } | |
1a0dc1ac | 2916 | } else if (reg->type == PTR_TO_CTX) { |
f1174f77 | 2917 | enum bpf_reg_type reg_type = SCALAR_VALUE; |
9e15db66 | 2918 | u32 btf_id = 0; |
19de99f7 | 2919 | |
1be7f75d AS |
2920 | if (t == BPF_WRITE && value_regno >= 0 && |
2921 | is_pointer_value(env, value_regno)) { | |
61bd5218 | 2922 | verbose(env, "R%d leaks addr into ctx\n", value_regno); |
1be7f75d AS |
2923 | return -EACCES; |
2924 | } | |
f1174f77 | 2925 | |
58990d1f DB |
2926 | err = check_ctx_reg(env, reg, regno); |
2927 | if (err < 0) | |
2928 | return err; | |
2929 | ||
9e15db66 AS |
2930 | err = check_ctx_access(env, insn_idx, off, size, t, ®_type, &btf_id); |
2931 | if (err) | |
2932 | verbose_linfo(env, insn_idx, "; "); | |
969bf05e | 2933 | if (!err && t == BPF_READ && value_regno >= 0) { |
f1174f77 | 2934 | /* ctx access returns either a scalar, or a |
de8f3a83 DB |
2935 | * PTR_TO_PACKET[_META,_END]. In the latter |
2936 | * case, we know the offset is zero. | |
f1174f77 | 2937 | */ |
46f8bc92 | 2938 | if (reg_type == SCALAR_VALUE) { |
638f5b90 | 2939 | mark_reg_unknown(env, regs, value_regno); |
46f8bc92 | 2940 | } else { |
638f5b90 | 2941 | mark_reg_known_zero(env, regs, |
61bd5218 | 2942 | value_regno); |
46f8bc92 MKL |
2943 | if (reg_type_may_be_null(reg_type)) |
2944 | regs[value_regno].id = ++env->id_gen; | |
5327ed3d JW |
2945 | /* A load of ctx field could have different |
2946 | * actual load size with the one encoded in the | |
2947 | * insn. When the dst is PTR, it is for sure not | |
2948 | * a sub-register. | |
2949 | */ | |
2950 | regs[value_regno].subreg_def = DEF_NOT_SUBREG; | |
9e15db66 AS |
2951 | if (reg_type == PTR_TO_BTF_ID) |
2952 | regs[value_regno].btf_id = btf_id; | |
46f8bc92 | 2953 | } |
638f5b90 | 2954 | regs[value_regno].type = reg_type; |
969bf05e | 2955 | } |
17a52670 | 2956 | |
f1174f77 | 2957 | } else if (reg->type == PTR_TO_STACK) { |
f1174f77 | 2958 | off += reg->var_off.value; |
e4298d25 DB |
2959 | err = check_stack_access(env, reg, off, size); |
2960 | if (err) | |
2961 | return err; | |
8726679a | 2962 | |
f4d7e40a AS |
2963 | state = func(env, reg); |
2964 | err = update_stack_depth(env, state, off); | |
2965 | if (err) | |
2966 | return err; | |
8726679a | 2967 | |
638f5b90 | 2968 | if (t == BPF_WRITE) |
61bd5218 | 2969 | err = check_stack_write(env, state, off, size, |
af86ca4e | 2970 | value_regno, insn_idx); |
638f5b90 | 2971 | else |
61bd5218 JK |
2972 | err = check_stack_read(env, state, off, size, |
2973 | value_regno); | |
de8f3a83 | 2974 | } else if (reg_is_pkt_pointer(reg)) { |
3a0af8fd | 2975 | if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) { |
61bd5218 | 2976 | verbose(env, "cannot write into packet\n"); |
969bf05e AS |
2977 | return -EACCES; |
2978 | } | |
4acf6c0b BB |
2979 | if (t == BPF_WRITE && value_regno >= 0 && |
2980 | is_pointer_value(env, value_regno)) { | |
61bd5218 JK |
2981 | verbose(env, "R%d leaks addr into packet\n", |
2982 | value_regno); | |
4acf6c0b BB |
2983 | return -EACCES; |
2984 | } | |
9fd29c08 | 2985 | err = check_packet_access(env, regno, off, size, false); |
969bf05e | 2986 | if (!err && t == BPF_READ && value_regno >= 0) |
638f5b90 | 2987 | mark_reg_unknown(env, regs, value_regno); |
d58e468b PP |
2988 | } else if (reg->type == PTR_TO_FLOW_KEYS) { |
2989 | if (t == BPF_WRITE && value_regno >= 0 && | |
2990 | is_pointer_value(env, value_regno)) { | |
2991 | verbose(env, "R%d leaks addr into flow keys\n", | |
2992 | value_regno); | |
2993 | return -EACCES; | |
2994 | } | |
2995 | ||
2996 | err = check_flow_keys_access(env, off, size); | |
2997 | if (!err && t == BPF_READ && value_regno >= 0) | |
2998 | mark_reg_unknown(env, regs, value_regno); | |
46f8bc92 | 2999 | } else if (type_is_sk_pointer(reg->type)) { |
c64b7983 | 3000 | if (t == BPF_WRITE) { |
46f8bc92 MKL |
3001 | verbose(env, "R%d cannot write into %s\n", |
3002 | regno, reg_type_str[reg->type]); | |
c64b7983 JS |
3003 | return -EACCES; |
3004 | } | |
5f456649 | 3005 | err = check_sock_access(env, insn_idx, regno, off, size, t); |
c64b7983 JS |
3006 | if (!err && value_regno >= 0) |
3007 | mark_reg_unknown(env, regs, value_regno); | |
9df1c28b MM |
3008 | } else if (reg->type == PTR_TO_TP_BUFFER) { |
3009 | err = check_tp_buffer_access(env, reg, regno, off, size); | |
3010 | if (!err && t == BPF_READ && value_regno >= 0) | |
3011 | mark_reg_unknown(env, regs, value_regno); | |
9e15db66 AS |
3012 | } else if (reg->type == PTR_TO_BTF_ID) { |
3013 | err = check_ptr_to_btf_access(env, regs, regno, off, size, t, | |
3014 | value_regno); | |
17a52670 | 3015 | } else { |
61bd5218 JK |
3016 | verbose(env, "R%d invalid mem access '%s'\n", regno, |
3017 | reg_type_str[reg->type]); | |
17a52670 AS |
3018 | return -EACCES; |
3019 | } | |
969bf05e | 3020 | |
f1174f77 | 3021 | if (!err && size < BPF_REG_SIZE && value_regno >= 0 && t == BPF_READ && |
638f5b90 | 3022 | regs[value_regno].type == SCALAR_VALUE) { |
f1174f77 | 3023 | /* b/h/w load zero-extends, mark upper bits as known 0 */ |
0c17d1d2 | 3024 | coerce_reg_to_size(®s[value_regno], size); |
969bf05e | 3025 | } |
17a52670 AS |
3026 | return err; |
3027 | } | |
3028 | ||
31fd8581 | 3029 | static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_insn *insn) |
17a52670 | 3030 | { |
17a52670 AS |
3031 | int err; |
3032 | ||
3033 | if ((BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) || | |
3034 | insn->imm != 0) { | |
61bd5218 | 3035 | verbose(env, "BPF_XADD uses reserved fields\n"); |
17a52670 AS |
3036 | return -EINVAL; |
3037 | } | |
3038 | ||
3039 | /* check src1 operand */ | |
dc503a8a | 3040 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
3041 | if (err) |
3042 | return err; | |
3043 | ||
3044 | /* check src2 operand */ | |
dc503a8a | 3045 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
3046 | if (err) |
3047 | return err; | |
3048 | ||
6bdf6abc | 3049 | if (is_pointer_value(env, insn->src_reg)) { |
61bd5218 | 3050 | verbose(env, "R%d leaks addr into mem\n", insn->src_reg); |
6bdf6abc DB |
3051 | return -EACCES; |
3052 | } | |
3053 | ||
ca369602 | 3054 | if (is_ctx_reg(env, insn->dst_reg) || |
4b5defde | 3055 | is_pkt_reg(env, insn->dst_reg) || |
46f8bc92 MKL |
3056 | is_flow_key_reg(env, insn->dst_reg) || |
3057 | is_sk_reg(env, insn->dst_reg)) { | |
ca369602 | 3058 | verbose(env, "BPF_XADD stores into R%d %s is not allowed\n", |
2a159c6f DB |
3059 | insn->dst_reg, |
3060 | reg_type_str[reg_state(env, insn->dst_reg)->type]); | |
f37a8cb8 DB |
3061 | return -EACCES; |
3062 | } | |
3063 | ||
17a52670 | 3064 | /* check whether atomic_add can read the memory */ |
31fd8581 | 3065 | err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off, |
ca369602 | 3066 | BPF_SIZE(insn->code), BPF_READ, -1, true); |
17a52670 AS |
3067 | if (err) |
3068 | return err; | |
3069 | ||
3070 | /* check whether atomic_add can write into the same memory */ | |
31fd8581 | 3071 | return check_mem_access(env, insn_idx, insn->dst_reg, insn->off, |
ca369602 | 3072 | BPF_SIZE(insn->code), BPF_WRITE, -1, true); |
17a52670 AS |
3073 | } |
3074 | ||
2011fccf AI |
3075 | static int __check_stack_boundary(struct bpf_verifier_env *env, u32 regno, |
3076 | int off, int access_size, | |
3077 | bool zero_size_allowed) | |
3078 | { | |
3079 | struct bpf_reg_state *reg = reg_state(env, regno); | |
3080 | ||
3081 | if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 || | |
3082 | access_size < 0 || (access_size == 0 && !zero_size_allowed)) { | |
3083 | if (tnum_is_const(reg->var_off)) { | |
3084 | verbose(env, "invalid stack type R%d off=%d access_size=%d\n", | |
3085 | regno, off, access_size); | |
3086 | } else { | |
3087 | char tn_buf[48]; | |
3088 | ||
3089 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
3090 | verbose(env, "invalid stack type R%d var_off=%s access_size=%d\n", | |
3091 | regno, tn_buf, access_size); | |
3092 | } | |
3093 | return -EACCES; | |
3094 | } | |
3095 | return 0; | |
3096 | } | |
3097 | ||
17a52670 AS |
3098 | /* when register 'regno' is passed into function that will read 'access_size' |
3099 | * bytes from that pointer, make sure that it's within stack boundary | |
f1174f77 EC |
3100 | * and all elements of stack are initialized. |
3101 | * Unlike most pointer bounds-checking functions, this one doesn't take an | |
3102 | * 'off' argument, so it has to add in reg->off itself. | |
17a52670 | 3103 | */ |
58e2af8b | 3104 | static int check_stack_boundary(struct bpf_verifier_env *env, int regno, |
435faee1 DB |
3105 | int access_size, bool zero_size_allowed, |
3106 | struct bpf_call_arg_meta *meta) | |
17a52670 | 3107 | { |
2a159c6f | 3108 | struct bpf_reg_state *reg = reg_state(env, regno); |
f4d7e40a | 3109 | struct bpf_func_state *state = func(env, reg); |
f7cf25b2 | 3110 | int err, min_off, max_off, i, j, slot, spi; |
17a52670 | 3111 | |
914cb781 | 3112 | if (reg->type != PTR_TO_STACK) { |
f1174f77 | 3113 | /* Allow zero-byte read from NULL, regardless of pointer type */ |
8e2fe1d9 | 3114 | if (zero_size_allowed && access_size == 0 && |
914cb781 | 3115 | register_is_null(reg)) |
8e2fe1d9 DB |
3116 | return 0; |
3117 | ||
61bd5218 | 3118 | verbose(env, "R%d type=%s expected=%s\n", regno, |
914cb781 | 3119 | reg_type_str[reg->type], |
8e2fe1d9 | 3120 | reg_type_str[PTR_TO_STACK]); |
17a52670 | 3121 | return -EACCES; |
8e2fe1d9 | 3122 | } |
17a52670 | 3123 | |
2011fccf AI |
3124 | if (tnum_is_const(reg->var_off)) { |
3125 | min_off = max_off = reg->var_off.value + reg->off; | |
3126 | err = __check_stack_boundary(env, regno, min_off, access_size, | |
3127 | zero_size_allowed); | |
3128 | if (err) | |
3129 | return err; | |
3130 | } else { | |
088ec26d AI |
3131 | /* Variable offset is prohibited for unprivileged mode for |
3132 | * simplicity since it requires corresponding support in | |
3133 | * Spectre masking for stack ALU. | |
3134 | * See also retrieve_ptr_limit(). | |
3135 | */ | |
3136 | if (!env->allow_ptr_leaks) { | |
3137 | char tn_buf[48]; | |
f1174f77 | 3138 | |
088ec26d AI |
3139 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); |
3140 | verbose(env, "R%d indirect variable offset stack access prohibited for !root, var_off=%s\n", | |
3141 | regno, tn_buf); | |
3142 | return -EACCES; | |
3143 | } | |
f2bcd05e AI |
3144 | /* Only initialized buffer on stack is allowed to be accessed |
3145 | * with variable offset. With uninitialized buffer it's hard to | |
3146 | * guarantee that whole memory is marked as initialized on | |
3147 | * helper return since specific bounds are unknown what may | |
3148 | * cause uninitialized stack leaking. | |
3149 | */ | |
3150 | if (meta && meta->raw_mode) | |
3151 | meta = NULL; | |
3152 | ||
107c26a7 AI |
3153 | if (reg->smax_value >= BPF_MAX_VAR_OFF || |
3154 | reg->smax_value <= -BPF_MAX_VAR_OFF) { | |
3155 | verbose(env, "R%d unbounded indirect variable offset stack access\n", | |
3156 | regno); | |
3157 | return -EACCES; | |
3158 | } | |
2011fccf | 3159 | min_off = reg->smin_value + reg->off; |
107c26a7 | 3160 | max_off = reg->smax_value + reg->off; |
2011fccf AI |
3161 | err = __check_stack_boundary(env, regno, min_off, access_size, |
3162 | zero_size_allowed); | |
107c26a7 AI |
3163 | if (err) { |
3164 | verbose(env, "R%d min value is outside of stack bound\n", | |
3165 | regno); | |
2011fccf | 3166 | return err; |
107c26a7 | 3167 | } |
2011fccf AI |
3168 | err = __check_stack_boundary(env, regno, max_off, access_size, |
3169 | zero_size_allowed); | |
107c26a7 AI |
3170 | if (err) { |
3171 | verbose(env, "R%d max value is outside of stack bound\n", | |
3172 | regno); | |
2011fccf | 3173 | return err; |
107c26a7 | 3174 | } |
17a52670 AS |
3175 | } |
3176 | ||
435faee1 DB |
3177 | if (meta && meta->raw_mode) { |
3178 | meta->access_size = access_size; | |
3179 | meta->regno = regno; | |
3180 | return 0; | |
3181 | } | |
3182 | ||
2011fccf | 3183 | for (i = min_off; i < max_off + access_size; i++) { |
cc2b14d5 AS |
3184 | u8 *stype; |
3185 | ||
2011fccf | 3186 | slot = -i - 1; |
638f5b90 | 3187 | spi = slot / BPF_REG_SIZE; |
cc2b14d5 AS |
3188 | if (state->allocated_stack <= slot) |
3189 | goto err; | |
3190 | stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE]; | |
3191 | if (*stype == STACK_MISC) | |
3192 | goto mark; | |
3193 | if (*stype == STACK_ZERO) { | |
3194 | /* helper can write anything into the stack */ | |
3195 | *stype = STACK_MISC; | |
3196 | goto mark; | |
17a52670 | 3197 | } |
f7cf25b2 AS |
3198 | if (state->stack[spi].slot_type[0] == STACK_SPILL && |
3199 | state->stack[spi].spilled_ptr.type == SCALAR_VALUE) { | |
3200 | __mark_reg_unknown(&state->stack[spi].spilled_ptr); | |
3201 | for (j = 0; j < BPF_REG_SIZE; j++) | |
3202 | state->stack[spi].slot_type[j] = STACK_MISC; | |
3203 | goto mark; | |
3204 | } | |
3205 | ||
cc2b14d5 | 3206 | err: |
2011fccf AI |
3207 | if (tnum_is_const(reg->var_off)) { |
3208 | verbose(env, "invalid indirect read from stack off %d+%d size %d\n", | |
3209 | min_off, i - min_off, access_size); | |
3210 | } else { | |
3211 | char tn_buf[48]; | |
3212 | ||
3213 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
3214 | verbose(env, "invalid indirect read from stack var_off %s+%d size %d\n", | |
3215 | tn_buf, i - min_off, access_size); | |
3216 | } | |
cc2b14d5 AS |
3217 | return -EACCES; |
3218 | mark: | |
3219 | /* reading any byte out of 8-byte 'spill_slot' will cause | |
3220 | * the whole slot to be marked as 'read' | |
3221 | */ | |
679c782d | 3222 | mark_reg_read(env, &state->stack[spi].spilled_ptr, |
5327ed3d JW |
3223 | state->stack[spi].spilled_ptr.parent, |
3224 | REG_LIVE_READ64); | |
17a52670 | 3225 | } |
2011fccf | 3226 | return update_stack_depth(env, state, min_off); |
17a52670 AS |
3227 | } |
3228 | ||
06c1c049 GB |
3229 | static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, |
3230 | int access_size, bool zero_size_allowed, | |
3231 | struct bpf_call_arg_meta *meta) | |
3232 | { | |
638f5b90 | 3233 | struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; |
06c1c049 | 3234 | |
f1174f77 | 3235 | switch (reg->type) { |
06c1c049 | 3236 | case PTR_TO_PACKET: |
de8f3a83 | 3237 | case PTR_TO_PACKET_META: |
9fd29c08 YS |
3238 | return check_packet_access(env, regno, reg->off, access_size, |
3239 | zero_size_allowed); | |
06c1c049 | 3240 | case PTR_TO_MAP_VALUE: |
591fe988 DB |
3241 | if (check_map_access_type(env, regno, reg->off, access_size, |
3242 | meta && meta->raw_mode ? BPF_WRITE : | |
3243 | BPF_READ)) | |
3244 | return -EACCES; | |
9fd29c08 YS |
3245 | return check_map_access(env, regno, reg->off, access_size, |
3246 | zero_size_allowed); | |
f1174f77 | 3247 | default: /* scalar_value|ptr_to_stack or invalid ptr */ |
06c1c049 GB |
3248 | return check_stack_boundary(env, regno, access_size, |
3249 | zero_size_allowed, meta); | |
3250 | } | |
3251 | } | |
3252 | ||
d83525ca AS |
3253 | /* Implementation details: |
3254 | * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL | |
3255 | * Two bpf_map_lookups (even with the same key) will have different reg->id. | |
3256 | * For traditional PTR_TO_MAP_VALUE the verifier clears reg->id after | |
3257 | * value_or_null->value transition, since the verifier only cares about | |
3258 | * the range of access to valid map value pointer and doesn't care about actual | |
3259 | * address of the map element. | |
3260 | * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps | |
3261 | * reg->id > 0 after value_or_null->value transition. By doing so | |
3262 | * two bpf_map_lookups will be considered two different pointers that | |
3263 | * point to different bpf_spin_locks. | |
3264 | * The verifier allows taking only one bpf_spin_lock at a time to avoid | |
3265 | * dead-locks. | |
3266 | * Since only one bpf_spin_lock is allowed the checks are simpler than | |
3267 | * reg_is_refcounted() logic. The verifier needs to remember only | |
3268 | * one spin_lock instead of array of acquired_refs. | |
3269 | * cur_state->active_spin_lock remembers which map value element got locked | |
3270 | * and clears it after bpf_spin_unlock. | |
3271 | */ | |
3272 | static int process_spin_lock(struct bpf_verifier_env *env, int regno, | |
3273 | bool is_lock) | |
3274 | { | |
3275 | struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; | |
3276 | struct bpf_verifier_state *cur = env->cur_state; | |
3277 | bool is_const = tnum_is_const(reg->var_off); | |
3278 | struct bpf_map *map = reg->map_ptr; | |
3279 | u64 val = reg->var_off.value; | |
3280 | ||
3281 | if (reg->type != PTR_TO_MAP_VALUE) { | |
3282 | verbose(env, "R%d is not a pointer to map_value\n", regno); | |
3283 | return -EINVAL; | |
3284 | } | |
3285 | if (!is_const) { | |
3286 | verbose(env, | |
3287 | "R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n", | |
3288 | regno); | |
3289 | return -EINVAL; | |
3290 | } | |
3291 | if (!map->btf) { | |
3292 | verbose(env, | |
3293 | "map '%s' has to have BTF in order to use bpf_spin_lock\n", | |
3294 | map->name); | |
3295 | return -EINVAL; | |
3296 | } | |
3297 | if (!map_value_has_spin_lock(map)) { | |
3298 | if (map->spin_lock_off == -E2BIG) | |
3299 | verbose(env, | |
3300 | "map '%s' has more than one 'struct bpf_spin_lock'\n", | |
3301 | map->name); | |
3302 | else if (map->spin_lock_off == -ENOENT) | |
3303 | verbose(env, | |
3304 | "map '%s' doesn't have 'struct bpf_spin_lock'\n", | |
3305 | map->name); | |
3306 | else | |
3307 | verbose(env, | |
3308 | "map '%s' is not a struct type or bpf_spin_lock is mangled\n", | |
3309 | map->name); | |
3310 | return -EINVAL; | |
3311 | } | |
3312 | if (map->spin_lock_off != val + reg->off) { | |
3313 | verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock'\n", | |
3314 | val + reg->off); | |
3315 | return -EINVAL; | |
3316 | } | |
3317 | if (is_lock) { | |
3318 | if (cur->active_spin_lock) { | |
3319 | verbose(env, | |
3320 | "Locking two bpf_spin_locks are not allowed\n"); | |
3321 | return -EINVAL; | |
3322 | } | |
3323 | cur->active_spin_lock = reg->id; | |
3324 | } else { | |
3325 | if (!cur->active_spin_lock) { | |
3326 | verbose(env, "bpf_spin_unlock without taking a lock\n"); | |
3327 | return -EINVAL; | |
3328 | } | |
3329 | if (cur->active_spin_lock != reg->id) { | |
3330 | verbose(env, "bpf_spin_unlock of different lock\n"); | |
3331 | return -EINVAL; | |
3332 | } | |
3333 | cur->active_spin_lock = 0; | |
3334 | } | |
3335 | return 0; | |
3336 | } | |
3337 | ||
90133415 DB |
3338 | static bool arg_type_is_mem_ptr(enum bpf_arg_type type) |
3339 | { | |
3340 | return type == ARG_PTR_TO_MEM || | |
3341 | type == ARG_PTR_TO_MEM_OR_NULL || | |
3342 | type == ARG_PTR_TO_UNINIT_MEM; | |
3343 | } | |
3344 | ||
3345 | static bool arg_type_is_mem_size(enum bpf_arg_type type) | |
3346 | { | |
3347 | return type == ARG_CONST_SIZE || | |
3348 | type == ARG_CONST_SIZE_OR_ZERO; | |
3349 | } | |
3350 | ||
57c3bb72 AI |
3351 | static bool arg_type_is_int_ptr(enum bpf_arg_type type) |
3352 | { | |
3353 | return type == ARG_PTR_TO_INT || | |
3354 | type == ARG_PTR_TO_LONG; | |
3355 | } | |
3356 | ||
3357 | static int int_ptr_type_to_size(enum bpf_arg_type type) | |
3358 | { | |
3359 | if (type == ARG_PTR_TO_INT) | |
3360 | return sizeof(u32); | |
3361 | else if (type == ARG_PTR_TO_LONG) | |
3362 | return sizeof(u64); | |
3363 | ||
3364 | return -EINVAL; | |
3365 | } | |
3366 | ||
58e2af8b | 3367 | static int check_func_arg(struct bpf_verifier_env *env, u32 regno, |
33ff9823 DB |
3368 | enum bpf_arg_type arg_type, |
3369 | struct bpf_call_arg_meta *meta) | |
17a52670 | 3370 | { |
638f5b90 | 3371 | struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; |
6841de8b | 3372 | enum bpf_reg_type expected_type, type = reg->type; |
17a52670 AS |
3373 | int err = 0; |
3374 | ||
80f1d68c | 3375 | if (arg_type == ARG_DONTCARE) |
17a52670 AS |
3376 | return 0; |
3377 | ||
dc503a8a EC |
3378 | err = check_reg_arg(env, regno, SRC_OP); |
3379 | if (err) | |
3380 | return err; | |
17a52670 | 3381 | |
1be7f75d AS |
3382 | if (arg_type == ARG_ANYTHING) { |
3383 | if (is_pointer_value(env, regno)) { | |
61bd5218 JK |
3384 | verbose(env, "R%d leaks addr into helper function\n", |
3385 | regno); | |
1be7f75d AS |
3386 | return -EACCES; |
3387 | } | |
80f1d68c | 3388 | return 0; |
1be7f75d | 3389 | } |
80f1d68c | 3390 | |
de8f3a83 | 3391 | if (type_is_pkt_pointer(type) && |
3a0af8fd | 3392 | !may_access_direct_pkt_data(env, meta, BPF_READ)) { |
61bd5218 | 3393 | verbose(env, "helper access to the packet is not allowed\n"); |
6841de8b AS |
3394 | return -EACCES; |
3395 | } | |
3396 | ||
8e2fe1d9 | 3397 | if (arg_type == ARG_PTR_TO_MAP_KEY || |
2ea864c5 | 3398 | arg_type == ARG_PTR_TO_MAP_VALUE || |
6ac99e8f MKL |
3399 | arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE || |
3400 | arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL) { | |
17a52670 | 3401 | expected_type = PTR_TO_STACK; |
6ac99e8f MKL |
3402 | if (register_is_null(reg) && |
3403 | arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL) | |
3404 | /* final test in check_stack_boundary() */; | |
3405 | else if (!type_is_pkt_pointer(type) && | |
3406 | type != PTR_TO_MAP_VALUE && | |
3407 | type != expected_type) | |
6841de8b | 3408 | goto err_type; |
39f19ebb AS |
3409 | } else if (arg_type == ARG_CONST_SIZE || |
3410 | arg_type == ARG_CONST_SIZE_OR_ZERO) { | |
f1174f77 EC |
3411 | expected_type = SCALAR_VALUE; |
3412 | if (type != expected_type) | |
6841de8b | 3413 | goto err_type; |
17a52670 AS |
3414 | } else if (arg_type == ARG_CONST_MAP_PTR) { |
3415 | expected_type = CONST_PTR_TO_MAP; | |
6841de8b AS |
3416 | if (type != expected_type) |
3417 | goto err_type; | |
608cd71a AS |
3418 | } else if (arg_type == ARG_PTR_TO_CTX) { |
3419 | expected_type = PTR_TO_CTX; | |
6841de8b AS |
3420 | if (type != expected_type) |
3421 | goto err_type; | |
58990d1f DB |
3422 | err = check_ctx_reg(env, reg, regno); |
3423 | if (err < 0) | |
3424 | return err; | |
46f8bc92 MKL |
3425 | } else if (arg_type == ARG_PTR_TO_SOCK_COMMON) { |
3426 | expected_type = PTR_TO_SOCK_COMMON; | |
3427 | /* Any sk pointer can be ARG_PTR_TO_SOCK_COMMON */ | |
3428 | if (!type_is_sk_pointer(type)) | |
3429 | goto err_type; | |
1b986589 MKL |
3430 | if (reg->ref_obj_id) { |
3431 | if (meta->ref_obj_id) { | |
3432 | verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n", | |
3433 | regno, reg->ref_obj_id, | |
3434 | meta->ref_obj_id); | |
3435 | return -EFAULT; | |
3436 | } | |
3437 | meta->ref_obj_id = reg->ref_obj_id; | |
fd978bf7 | 3438 | } |
6ac99e8f MKL |
3439 | } else if (arg_type == ARG_PTR_TO_SOCKET) { |
3440 | expected_type = PTR_TO_SOCKET; | |
3441 | if (type != expected_type) | |
3442 | goto err_type; | |
a7658e1a AS |
3443 | } else if (arg_type == ARG_PTR_TO_BTF_ID) { |
3444 | expected_type = PTR_TO_BTF_ID; | |
3445 | if (type != expected_type) | |
3446 | goto err_type; | |
3447 | if (reg->btf_id != meta->btf_id) { | |
3448 | verbose(env, "Helper has type %s got %s in R%d\n", | |
3449 | kernel_type_name(meta->btf_id), | |
3450 | kernel_type_name(reg->btf_id), regno); | |
3451 | ||
3452 | return -EACCES; | |
3453 | } | |
3454 | if (!tnum_is_const(reg->var_off) || reg->var_off.value || reg->off) { | |
3455 | verbose(env, "R%d is a pointer to in-kernel struct with non-zero offset\n", | |
3456 | regno); | |
3457 | return -EACCES; | |
3458 | } | |
d83525ca AS |
3459 | } else if (arg_type == ARG_PTR_TO_SPIN_LOCK) { |
3460 | if (meta->func_id == BPF_FUNC_spin_lock) { | |
3461 | if (process_spin_lock(env, regno, true)) | |
3462 | return -EACCES; | |
3463 | } else if (meta->func_id == BPF_FUNC_spin_unlock) { | |
3464 | if (process_spin_lock(env, regno, false)) | |
3465 | return -EACCES; | |
3466 | } else { | |
3467 | verbose(env, "verifier internal error\n"); | |
3468 | return -EFAULT; | |
3469 | } | |
90133415 | 3470 | } else if (arg_type_is_mem_ptr(arg_type)) { |
8e2fe1d9 DB |
3471 | expected_type = PTR_TO_STACK; |
3472 | /* One exception here. In case function allows for NULL to be | |
f1174f77 | 3473 | * passed in as argument, it's a SCALAR_VALUE type. Final test |
8e2fe1d9 DB |
3474 | * happens during stack boundary checking. |
3475 | */ | |
914cb781 | 3476 | if (register_is_null(reg) && |
db1ac496 | 3477 | arg_type == ARG_PTR_TO_MEM_OR_NULL) |
6841de8b | 3478 | /* final test in check_stack_boundary() */; |
de8f3a83 DB |
3479 | else if (!type_is_pkt_pointer(type) && |
3480 | type != PTR_TO_MAP_VALUE && | |
f1174f77 | 3481 | type != expected_type) |
6841de8b | 3482 | goto err_type; |
39f19ebb | 3483 | meta->raw_mode = arg_type == ARG_PTR_TO_UNINIT_MEM; |
57c3bb72 AI |
3484 | } else if (arg_type_is_int_ptr(arg_type)) { |
3485 | expected_type = PTR_TO_STACK; | |
3486 | if (!type_is_pkt_pointer(type) && | |
3487 | type != PTR_TO_MAP_VALUE && | |
3488 | type != expected_type) | |
3489 | goto err_type; | |
17a52670 | 3490 | } else { |
61bd5218 | 3491 | verbose(env, "unsupported arg_type %d\n", arg_type); |
17a52670 AS |
3492 | return -EFAULT; |
3493 | } | |
3494 | ||
17a52670 AS |
3495 | if (arg_type == ARG_CONST_MAP_PTR) { |
3496 | /* bpf_map_xxx(map_ptr) call: remember that map_ptr */ | |
33ff9823 | 3497 | meta->map_ptr = reg->map_ptr; |
17a52670 AS |
3498 | } else if (arg_type == ARG_PTR_TO_MAP_KEY) { |
3499 | /* bpf_map_xxx(..., map_ptr, ..., key) call: | |
3500 | * check that [key, key + map->key_size) are within | |
3501 | * stack limits and initialized | |
3502 | */ | |
33ff9823 | 3503 | if (!meta->map_ptr) { |
17a52670 AS |
3504 | /* in function declaration map_ptr must come before |
3505 | * map_key, so that it's verified and known before | |
3506 | * we have to check map_key here. Otherwise it means | |
3507 | * that kernel subsystem misconfigured verifier | |
3508 | */ | |
61bd5218 | 3509 | verbose(env, "invalid map_ptr to access map->key\n"); |
17a52670 AS |
3510 | return -EACCES; |
3511 | } | |
d71962f3 PC |
3512 | err = check_helper_mem_access(env, regno, |
3513 | meta->map_ptr->key_size, false, | |
3514 | NULL); | |
2ea864c5 | 3515 | } else if (arg_type == ARG_PTR_TO_MAP_VALUE || |
6ac99e8f MKL |
3516 | (arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL && |
3517 | !register_is_null(reg)) || | |
2ea864c5 | 3518 | arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE) { |
17a52670 AS |
3519 | /* bpf_map_xxx(..., map_ptr, ..., value) call: |
3520 | * check [value, value + map->value_size) validity | |
3521 | */ | |
33ff9823 | 3522 | if (!meta->map_ptr) { |
17a52670 | 3523 | /* kernel subsystem misconfigured verifier */ |
61bd5218 | 3524 | verbose(env, "invalid map_ptr to access map->value\n"); |
17a52670 AS |
3525 | return -EACCES; |
3526 | } | |
2ea864c5 | 3527 | meta->raw_mode = (arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE); |
d71962f3 PC |
3528 | err = check_helper_mem_access(env, regno, |
3529 | meta->map_ptr->value_size, false, | |
2ea864c5 | 3530 | meta); |
90133415 | 3531 | } else if (arg_type_is_mem_size(arg_type)) { |
39f19ebb | 3532 | bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO); |
17a52670 | 3533 | |
849fa506 YS |
3534 | /* remember the mem_size which may be used later |
3535 | * to refine return values. | |
3536 | */ | |
3537 | meta->msize_smax_value = reg->smax_value; | |
3538 | meta->msize_umax_value = reg->umax_value; | |
3539 | ||
f1174f77 EC |
3540 | /* The register is SCALAR_VALUE; the access check |
3541 | * happens using its boundaries. | |
06c1c049 | 3542 | */ |
f1174f77 | 3543 | if (!tnum_is_const(reg->var_off)) |
06c1c049 GB |
3544 | /* For unprivileged variable accesses, disable raw |
3545 | * mode so that the program is required to | |
3546 | * initialize all the memory that the helper could | |
3547 | * just partially fill up. | |
3548 | */ | |
3549 | meta = NULL; | |
3550 | ||
b03c9f9f | 3551 | if (reg->smin_value < 0) { |
61bd5218 | 3552 | verbose(env, "R%d min value is negative, either use unsigned or 'var &= const'\n", |
f1174f77 EC |
3553 | regno); |
3554 | return -EACCES; | |
3555 | } | |
06c1c049 | 3556 | |
b03c9f9f | 3557 | if (reg->umin_value == 0) { |
f1174f77 EC |
3558 | err = check_helper_mem_access(env, regno - 1, 0, |
3559 | zero_size_allowed, | |
3560 | meta); | |
06c1c049 GB |
3561 | if (err) |
3562 | return err; | |
06c1c049 | 3563 | } |
f1174f77 | 3564 | |
b03c9f9f | 3565 | if (reg->umax_value >= BPF_MAX_VAR_SIZ) { |
61bd5218 | 3566 | verbose(env, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n", |
f1174f77 EC |
3567 | regno); |
3568 | return -EACCES; | |
3569 | } | |
3570 | err = check_helper_mem_access(env, regno - 1, | |
b03c9f9f | 3571 | reg->umax_value, |
f1174f77 | 3572 | zero_size_allowed, meta); |
b5dc0163 AS |
3573 | if (!err) |
3574 | err = mark_chain_precision(env, regno); | |
57c3bb72 AI |
3575 | } else if (arg_type_is_int_ptr(arg_type)) { |
3576 | int size = int_ptr_type_to_size(arg_type); | |
3577 | ||
3578 | err = check_helper_mem_access(env, regno, size, false, meta); | |
3579 | if (err) | |
3580 | return err; | |
3581 | err = check_ptr_alignment(env, reg, 0, size, true); | |
17a52670 AS |
3582 | } |
3583 | ||
3584 | return err; | |
6841de8b | 3585 | err_type: |
61bd5218 | 3586 | verbose(env, "R%d type=%s expected=%s\n", regno, |
6841de8b AS |
3587 | reg_type_str[type], reg_type_str[expected_type]); |
3588 | return -EACCES; | |
17a52670 AS |
3589 | } |
3590 | ||
61bd5218 JK |
3591 | static int check_map_func_compatibility(struct bpf_verifier_env *env, |
3592 | struct bpf_map *map, int func_id) | |
35578d79 | 3593 | { |
35578d79 KX |
3594 | if (!map) |
3595 | return 0; | |
3596 | ||
6aff67c8 AS |
3597 | /* We need a two way check, first is from map perspective ... */ |
3598 | switch (map->map_type) { | |
3599 | case BPF_MAP_TYPE_PROG_ARRAY: | |
3600 | if (func_id != BPF_FUNC_tail_call) | |
3601 | goto error; | |
3602 | break; | |
3603 | case BPF_MAP_TYPE_PERF_EVENT_ARRAY: | |
3604 | if (func_id != BPF_FUNC_perf_event_read && | |
908432ca | 3605 | func_id != BPF_FUNC_perf_event_output && |
a7658e1a | 3606 | func_id != BPF_FUNC_skb_output && |
908432ca | 3607 | func_id != BPF_FUNC_perf_event_read_value) |
6aff67c8 AS |
3608 | goto error; |
3609 | break; | |
3610 | case BPF_MAP_TYPE_STACK_TRACE: | |
3611 | if (func_id != BPF_FUNC_get_stackid) | |
3612 | goto error; | |
3613 | break; | |
4ed8ec52 | 3614 | case BPF_MAP_TYPE_CGROUP_ARRAY: |
60747ef4 | 3615 | if (func_id != BPF_FUNC_skb_under_cgroup && |
60d20f91 | 3616 | func_id != BPF_FUNC_current_task_under_cgroup) |
4a482f34 MKL |
3617 | goto error; |
3618 | break; | |
cd339431 | 3619 | case BPF_MAP_TYPE_CGROUP_STORAGE: |
b741f163 | 3620 | case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE: |
cd339431 RG |
3621 | if (func_id != BPF_FUNC_get_local_storage) |
3622 | goto error; | |
3623 | break; | |
546ac1ff | 3624 | case BPF_MAP_TYPE_DEVMAP: |
6f9d451a | 3625 | case BPF_MAP_TYPE_DEVMAP_HASH: |
0cdbb4b0 THJ |
3626 | if (func_id != BPF_FUNC_redirect_map && |
3627 | func_id != BPF_FUNC_map_lookup_elem) | |
546ac1ff JF |
3628 | goto error; |
3629 | break; | |
fbfc504a BT |
3630 | /* Restrict bpf side of cpumap and xskmap, open when use-cases |
3631 | * appear. | |
3632 | */ | |
6710e112 JDB |
3633 | case BPF_MAP_TYPE_CPUMAP: |
3634 | if (func_id != BPF_FUNC_redirect_map) | |
3635 | goto error; | |
3636 | break; | |
fada7fdc JL |
3637 | case BPF_MAP_TYPE_XSKMAP: |
3638 | if (func_id != BPF_FUNC_redirect_map && | |
3639 | func_id != BPF_FUNC_map_lookup_elem) | |
3640 | goto error; | |
3641 | break; | |
56f668df | 3642 | case BPF_MAP_TYPE_ARRAY_OF_MAPS: |
bcc6b1b7 | 3643 | case BPF_MAP_TYPE_HASH_OF_MAPS: |
56f668df MKL |
3644 | if (func_id != BPF_FUNC_map_lookup_elem) |
3645 | goto error; | |
16a43625 | 3646 | break; |
174a79ff JF |
3647 | case BPF_MAP_TYPE_SOCKMAP: |
3648 | if (func_id != BPF_FUNC_sk_redirect_map && | |
3649 | func_id != BPF_FUNC_sock_map_update && | |
4f738adb JF |
3650 | func_id != BPF_FUNC_map_delete_elem && |
3651 | func_id != BPF_FUNC_msg_redirect_map) | |
174a79ff JF |
3652 | goto error; |
3653 | break; | |
81110384 JF |
3654 | case BPF_MAP_TYPE_SOCKHASH: |
3655 | if (func_id != BPF_FUNC_sk_redirect_hash && | |
3656 | func_id != BPF_FUNC_sock_hash_update && | |
3657 | func_id != BPF_FUNC_map_delete_elem && | |
3658 | func_id != BPF_FUNC_msg_redirect_hash) | |
3659 | goto error; | |
3660 | break; | |
2dbb9b9e MKL |
3661 | case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY: |
3662 | if (func_id != BPF_FUNC_sk_select_reuseport) | |
3663 | goto error; | |
3664 | break; | |
f1a2e44a MV |
3665 | case BPF_MAP_TYPE_QUEUE: |
3666 | case BPF_MAP_TYPE_STACK: | |
3667 | if (func_id != BPF_FUNC_map_peek_elem && | |
3668 | func_id != BPF_FUNC_map_pop_elem && | |
3669 | func_id != BPF_FUNC_map_push_elem) | |
3670 | goto error; | |
3671 | break; | |
6ac99e8f MKL |
3672 | case BPF_MAP_TYPE_SK_STORAGE: |
3673 | if (func_id != BPF_FUNC_sk_storage_get && | |
3674 | func_id != BPF_FUNC_sk_storage_delete) | |
3675 | goto error; | |
3676 | break; | |
6aff67c8 AS |
3677 | default: |
3678 | break; | |
3679 | } | |
3680 | ||
3681 | /* ... and second from the function itself. */ | |
3682 | switch (func_id) { | |
3683 | case BPF_FUNC_tail_call: | |
3684 | if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) | |
3685 | goto error; | |
f910cefa | 3686 | if (env->subprog_cnt > 1) { |
f4d7e40a AS |
3687 | verbose(env, "tail_calls are not allowed in programs with bpf-to-bpf calls\n"); |
3688 | return -EINVAL; | |
3689 | } | |
6aff67c8 AS |
3690 | break; |
3691 | case BPF_FUNC_perf_event_read: | |
3692 | case BPF_FUNC_perf_event_output: | |
908432ca | 3693 | case BPF_FUNC_perf_event_read_value: |
a7658e1a | 3694 | case BPF_FUNC_skb_output: |
6aff67c8 AS |
3695 | if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) |
3696 | goto error; | |
3697 | break; | |
3698 | case BPF_FUNC_get_stackid: | |
3699 | if (map->map_type != BPF_MAP_TYPE_STACK_TRACE) | |
3700 | goto error; | |
3701 | break; | |
60d20f91 | 3702 | case BPF_FUNC_current_task_under_cgroup: |
747ea55e | 3703 | case BPF_FUNC_skb_under_cgroup: |
4a482f34 MKL |
3704 | if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY) |
3705 | goto error; | |
3706 | break; | |
97f91a7c | 3707 | case BPF_FUNC_redirect_map: |
9c270af3 | 3708 | if (map->map_type != BPF_MAP_TYPE_DEVMAP && |
6f9d451a | 3709 | map->map_type != BPF_MAP_TYPE_DEVMAP_HASH && |
fbfc504a BT |
3710 | map->map_type != BPF_MAP_TYPE_CPUMAP && |
3711 | map->map_type != BPF_MAP_TYPE_XSKMAP) | |
97f91a7c JF |
3712 | goto error; |
3713 | break; | |
174a79ff | 3714 | case BPF_FUNC_sk_redirect_map: |
4f738adb | 3715 | case BPF_FUNC_msg_redirect_map: |
81110384 | 3716 | case BPF_FUNC_sock_map_update: |
174a79ff JF |
3717 | if (map->map_type != BPF_MAP_TYPE_SOCKMAP) |
3718 | goto error; | |
3719 | break; | |
81110384 JF |
3720 | case BPF_FUNC_sk_redirect_hash: |
3721 | case BPF_FUNC_msg_redirect_hash: | |
3722 | case BPF_FUNC_sock_hash_update: | |
3723 | if (map->map_type != BPF_MAP_TYPE_SOCKHASH) | |
174a79ff JF |
3724 | goto error; |
3725 | break; | |
cd339431 | 3726 | case BPF_FUNC_get_local_storage: |
b741f163 RG |
3727 | if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE && |
3728 | map->map_type != BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) | |
cd339431 RG |
3729 | goto error; |
3730 | break; | |
2dbb9b9e MKL |
3731 | case BPF_FUNC_sk_select_reuseport: |
3732 | if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) | |
3733 | goto error; | |
3734 | break; | |
f1a2e44a MV |
3735 | case BPF_FUNC_map_peek_elem: |
3736 | case BPF_FUNC_map_pop_elem: | |
3737 | case BPF_FUNC_map_push_elem: | |
3738 | if (map->map_type != BPF_MAP_TYPE_QUEUE && | |
3739 | map->map_type != BPF_MAP_TYPE_STACK) | |
3740 | goto error; | |
3741 | break; | |
6ac99e8f MKL |
3742 | case BPF_FUNC_sk_storage_get: |
3743 | case BPF_FUNC_sk_storage_delete: | |
3744 | if (map->map_type != BPF_MAP_TYPE_SK_STORAGE) | |
3745 | goto error; | |
3746 | break; | |
6aff67c8 AS |
3747 | default: |
3748 | break; | |
35578d79 KX |
3749 | } |
3750 | ||
3751 | return 0; | |
6aff67c8 | 3752 | error: |
61bd5218 | 3753 | verbose(env, "cannot pass map_type %d into func %s#%d\n", |
ebb676da | 3754 | map->map_type, func_id_name(func_id), func_id); |
6aff67c8 | 3755 | return -EINVAL; |
35578d79 KX |
3756 | } |
3757 | ||
90133415 | 3758 | static bool check_raw_mode_ok(const struct bpf_func_proto *fn) |
435faee1 DB |
3759 | { |
3760 | int count = 0; | |
3761 | ||
39f19ebb | 3762 | if (fn->arg1_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 3763 | count++; |
39f19ebb | 3764 | if (fn->arg2_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 3765 | count++; |
39f19ebb | 3766 | if (fn->arg3_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 3767 | count++; |
39f19ebb | 3768 | if (fn->arg4_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 3769 | count++; |
39f19ebb | 3770 | if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 DB |
3771 | count++; |
3772 | ||
90133415 DB |
3773 | /* We only support one arg being in raw mode at the moment, |
3774 | * which is sufficient for the helper functions we have | |
3775 | * right now. | |
3776 | */ | |
3777 | return count <= 1; | |
3778 | } | |
3779 | ||
3780 | static bool check_args_pair_invalid(enum bpf_arg_type arg_curr, | |
3781 | enum bpf_arg_type arg_next) | |
3782 | { | |
3783 | return (arg_type_is_mem_ptr(arg_curr) && | |
3784 | !arg_type_is_mem_size(arg_next)) || | |
3785 | (!arg_type_is_mem_ptr(arg_curr) && | |
3786 | arg_type_is_mem_size(arg_next)); | |
3787 | } | |
3788 | ||
3789 | static bool check_arg_pair_ok(const struct bpf_func_proto *fn) | |
3790 | { | |
3791 | /* bpf_xxx(..., buf, len) call will access 'len' | |
3792 | * bytes from memory 'buf'. Both arg types need | |
3793 | * to be paired, so make sure there's no buggy | |
3794 | * helper function specification. | |
3795 | */ | |
3796 | if (arg_type_is_mem_size(fn->arg1_type) || | |
3797 | arg_type_is_mem_ptr(fn->arg5_type) || | |
3798 | check_args_pair_invalid(fn->arg1_type, fn->arg2_type) || | |
3799 | check_args_pair_invalid(fn->arg2_type, fn->arg3_type) || | |
3800 | check_args_pair_invalid(fn->arg3_type, fn->arg4_type) || | |
3801 | check_args_pair_invalid(fn->arg4_type, fn->arg5_type)) | |
3802 | return false; | |
3803 | ||
3804 | return true; | |
3805 | } | |
3806 | ||
1b986589 | 3807 | static bool check_refcount_ok(const struct bpf_func_proto *fn, int func_id) |
fd978bf7 JS |
3808 | { |
3809 | int count = 0; | |
3810 | ||
1b986589 | 3811 | if (arg_type_may_be_refcounted(fn->arg1_type)) |
fd978bf7 | 3812 | count++; |
1b986589 | 3813 | if (arg_type_may_be_refcounted(fn->arg2_type)) |
fd978bf7 | 3814 | count++; |
1b986589 | 3815 | if (arg_type_may_be_refcounted(fn->arg3_type)) |
fd978bf7 | 3816 | count++; |
1b986589 | 3817 | if (arg_type_may_be_refcounted(fn->arg4_type)) |
fd978bf7 | 3818 | count++; |
1b986589 | 3819 | if (arg_type_may_be_refcounted(fn->arg5_type)) |
fd978bf7 JS |
3820 | count++; |
3821 | ||
1b986589 MKL |
3822 | /* A reference acquiring function cannot acquire |
3823 | * another refcounted ptr. | |
3824 | */ | |
3825 | if (is_acquire_function(func_id) && count) | |
3826 | return false; | |
3827 | ||
fd978bf7 JS |
3828 | /* We only support one arg being unreferenced at the moment, |
3829 | * which is sufficient for the helper functions we have right now. | |
3830 | */ | |
3831 | return count <= 1; | |
3832 | } | |
3833 | ||
1b986589 | 3834 | static int check_func_proto(const struct bpf_func_proto *fn, int func_id) |
90133415 DB |
3835 | { |
3836 | return check_raw_mode_ok(fn) && | |
fd978bf7 | 3837 | check_arg_pair_ok(fn) && |
1b986589 | 3838 | check_refcount_ok(fn, func_id) ? 0 : -EINVAL; |
435faee1 DB |
3839 | } |
3840 | ||
de8f3a83 DB |
3841 | /* Packet data might have moved, any old PTR_TO_PACKET[_META,_END] |
3842 | * are now invalid, so turn them into unknown SCALAR_VALUE. | |
f1174f77 | 3843 | */ |
f4d7e40a AS |
3844 | static void __clear_all_pkt_pointers(struct bpf_verifier_env *env, |
3845 | struct bpf_func_state *state) | |
969bf05e | 3846 | { |
58e2af8b | 3847 | struct bpf_reg_state *regs = state->regs, *reg; |
969bf05e AS |
3848 | int i; |
3849 | ||
3850 | for (i = 0; i < MAX_BPF_REG; i++) | |
de8f3a83 | 3851 | if (reg_is_pkt_pointer_any(®s[i])) |
61bd5218 | 3852 | mark_reg_unknown(env, regs, i); |
969bf05e | 3853 | |
f3709f69 JS |
3854 | bpf_for_each_spilled_reg(i, state, reg) { |
3855 | if (!reg) | |
969bf05e | 3856 | continue; |
de8f3a83 DB |
3857 | if (reg_is_pkt_pointer_any(reg)) |
3858 | __mark_reg_unknown(reg); | |
969bf05e AS |
3859 | } |
3860 | } | |
3861 | ||
f4d7e40a AS |
3862 | static void clear_all_pkt_pointers(struct bpf_verifier_env *env) |
3863 | { | |
3864 | struct bpf_verifier_state *vstate = env->cur_state; | |
3865 | int i; | |
3866 | ||
3867 | for (i = 0; i <= vstate->curframe; i++) | |
3868 | __clear_all_pkt_pointers(env, vstate->frame[i]); | |
3869 | } | |
3870 | ||
fd978bf7 | 3871 | static void release_reg_references(struct bpf_verifier_env *env, |
1b986589 MKL |
3872 | struct bpf_func_state *state, |
3873 | int ref_obj_id) | |
fd978bf7 JS |
3874 | { |
3875 | struct bpf_reg_state *regs = state->regs, *reg; | |
3876 | int i; | |
3877 | ||
3878 | for (i = 0; i < MAX_BPF_REG; i++) | |
1b986589 | 3879 | if (regs[i].ref_obj_id == ref_obj_id) |
fd978bf7 JS |
3880 | mark_reg_unknown(env, regs, i); |
3881 | ||
3882 | bpf_for_each_spilled_reg(i, state, reg) { | |
3883 | if (!reg) | |
3884 | continue; | |
1b986589 | 3885 | if (reg->ref_obj_id == ref_obj_id) |
fd978bf7 JS |
3886 | __mark_reg_unknown(reg); |
3887 | } | |
3888 | } | |
3889 | ||
3890 | /* The pointer with the specified id has released its reference to kernel | |
3891 | * resources. Identify all copies of the same pointer and clear the reference. | |
3892 | */ | |
3893 | static int release_reference(struct bpf_verifier_env *env, | |
1b986589 | 3894 | int ref_obj_id) |
fd978bf7 JS |
3895 | { |
3896 | struct bpf_verifier_state *vstate = env->cur_state; | |
1b986589 | 3897 | int err; |
fd978bf7 JS |
3898 | int i; |
3899 | ||
1b986589 MKL |
3900 | err = release_reference_state(cur_func(env), ref_obj_id); |
3901 | if (err) | |
3902 | return err; | |
3903 | ||
fd978bf7 | 3904 | for (i = 0; i <= vstate->curframe; i++) |
1b986589 | 3905 | release_reg_references(env, vstate->frame[i], ref_obj_id); |
fd978bf7 | 3906 | |
1b986589 | 3907 | return 0; |
fd978bf7 JS |
3908 | } |
3909 | ||
f4d7e40a AS |
3910 | static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, |
3911 | int *insn_idx) | |
3912 | { | |
3913 | struct bpf_verifier_state *state = env->cur_state; | |
3914 | struct bpf_func_state *caller, *callee; | |
fd978bf7 | 3915 | int i, err, subprog, target_insn; |
f4d7e40a | 3916 | |
aada9ce6 | 3917 | if (state->curframe + 1 >= MAX_CALL_FRAMES) { |
f4d7e40a | 3918 | verbose(env, "the call stack of %d frames is too deep\n", |
aada9ce6 | 3919 | state->curframe + 2); |
f4d7e40a AS |
3920 | return -E2BIG; |
3921 | } | |
3922 | ||
3923 | target_insn = *insn_idx + insn->imm; | |
3924 | subprog = find_subprog(env, target_insn + 1); | |
3925 | if (subprog < 0) { | |
3926 | verbose(env, "verifier bug. No program starts at insn %d\n", | |
3927 | target_insn + 1); | |
3928 | return -EFAULT; | |
3929 | } | |
3930 | ||
3931 | caller = state->frame[state->curframe]; | |
3932 | if (state->frame[state->curframe + 1]) { | |
3933 | verbose(env, "verifier bug. Frame %d already allocated\n", | |
3934 | state->curframe + 1); | |
3935 | return -EFAULT; | |
3936 | } | |
3937 | ||
3938 | callee = kzalloc(sizeof(*callee), GFP_KERNEL); | |
3939 | if (!callee) | |
3940 | return -ENOMEM; | |
3941 | state->frame[state->curframe + 1] = callee; | |
3942 | ||
3943 | /* callee cannot access r0, r6 - r9 for reading and has to write | |
3944 | * into its own stack before reading from it. | |
3945 | * callee can read/write into caller's stack | |
3946 | */ | |
3947 | init_func_state(env, callee, | |
3948 | /* remember the callsite, it will be used by bpf_exit */ | |
3949 | *insn_idx /* callsite */, | |
3950 | state->curframe + 1 /* frameno within this callchain */, | |
f910cefa | 3951 | subprog /* subprog number within this prog */); |
f4d7e40a | 3952 | |
fd978bf7 JS |
3953 | /* Transfer references to the callee */ |
3954 | err = transfer_reference_state(callee, caller); | |
3955 | if (err) | |
3956 | return err; | |
3957 | ||
679c782d EC |
3958 | /* copy r1 - r5 args that callee can access. The copy includes parent |
3959 | * pointers, which connects us up to the liveness chain | |
3960 | */ | |
f4d7e40a AS |
3961 | for (i = BPF_REG_1; i <= BPF_REG_5; i++) |
3962 | callee->regs[i] = caller->regs[i]; | |
3963 | ||
679c782d | 3964 | /* after the call registers r0 - r5 were scratched */ |
f4d7e40a AS |
3965 | for (i = 0; i < CALLER_SAVED_REGS; i++) { |
3966 | mark_reg_not_init(env, caller->regs, caller_saved[i]); | |
3967 | check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK); | |
3968 | } | |
3969 | ||
3970 | /* only increment it after check_reg_arg() finished */ | |
3971 | state->curframe++; | |
3972 | ||
3973 | /* and go analyze first insn of the callee */ | |
3974 | *insn_idx = target_insn; | |
3975 | ||
06ee7115 | 3976 | if (env->log.level & BPF_LOG_LEVEL) { |
f4d7e40a AS |
3977 | verbose(env, "caller:\n"); |
3978 | print_verifier_state(env, caller); | |
3979 | verbose(env, "callee:\n"); | |
3980 | print_verifier_state(env, callee); | |
3981 | } | |
3982 | return 0; | |
3983 | } | |
3984 | ||
3985 | static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) | |
3986 | { | |
3987 | struct bpf_verifier_state *state = env->cur_state; | |
3988 | struct bpf_func_state *caller, *callee; | |
3989 | struct bpf_reg_state *r0; | |
fd978bf7 | 3990 | int err; |
f4d7e40a AS |
3991 | |
3992 | callee = state->frame[state->curframe]; | |
3993 | r0 = &callee->regs[BPF_REG_0]; | |
3994 | if (r0->type == PTR_TO_STACK) { | |
3995 | /* technically it's ok to return caller's stack pointer | |
3996 | * (or caller's caller's pointer) back to the caller, | |
3997 | * since these pointers are valid. Only current stack | |
3998 | * pointer will be invalid as soon as function exits, | |
3999 | * but let's be conservative | |
4000 | */ | |
4001 | verbose(env, "cannot return stack pointer to the caller\n"); | |
4002 | return -EINVAL; | |
4003 | } | |
4004 | ||
4005 | state->curframe--; | |
4006 | caller = state->frame[state->curframe]; | |
4007 | /* return to the caller whatever r0 had in the callee */ | |
4008 | caller->regs[BPF_REG_0] = *r0; | |
4009 | ||
fd978bf7 JS |
4010 | /* Transfer references to the caller */ |
4011 | err = transfer_reference_state(caller, callee); | |
4012 | if (err) | |
4013 | return err; | |
4014 | ||
f4d7e40a | 4015 | *insn_idx = callee->callsite + 1; |
06ee7115 | 4016 | if (env->log.level & BPF_LOG_LEVEL) { |
f4d7e40a AS |
4017 | verbose(env, "returning from callee:\n"); |
4018 | print_verifier_state(env, callee); | |
4019 | verbose(env, "to caller at %d:\n", *insn_idx); | |
4020 | print_verifier_state(env, caller); | |
4021 | } | |
4022 | /* clear everything in the callee */ | |
4023 | free_func_state(callee); | |
4024 | state->frame[state->curframe + 1] = NULL; | |
4025 | return 0; | |
4026 | } | |
4027 | ||
849fa506 YS |
4028 | static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type, |
4029 | int func_id, | |
4030 | struct bpf_call_arg_meta *meta) | |
4031 | { | |
4032 | struct bpf_reg_state *ret_reg = ®s[BPF_REG_0]; | |
4033 | ||
4034 | if (ret_type != RET_INTEGER || | |
4035 | (func_id != BPF_FUNC_get_stack && | |
4036 | func_id != BPF_FUNC_probe_read_str)) | |
4037 | return; | |
4038 | ||
4039 | ret_reg->smax_value = meta->msize_smax_value; | |
4040 | ret_reg->umax_value = meta->msize_umax_value; | |
4041 | __reg_deduce_bounds(ret_reg); | |
4042 | __reg_bound_offset(ret_reg); | |
4043 | } | |
4044 | ||
c93552c4 DB |
4045 | static int |
4046 | record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, | |
4047 | int func_id, int insn_idx) | |
4048 | { | |
4049 | struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx]; | |
591fe988 | 4050 | struct bpf_map *map = meta->map_ptr; |
c93552c4 DB |
4051 | |
4052 | if (func_id != BPF_FUNC_tail_call && | |
09772d92 DB |
4053 | func_id != BPF_FUNC_map_lookup_elem && |
4054 | func_id != BPF_FUNC_map_update_elem && | |
f1a2e44a MV |
4055 | func_id != BPF_FUNC_map_delete_elem && |
4056 | func_id != BPF_FUNC_map_push_elem && | |
4057 | func_id != BPF_FUNC_map_pop_elem && | |
4058 | func_id != BPF_FUNC_map_peek_elem) | |
c93552c4 | 4059 | return 0; |
09772d92 | 4060 | |
591fe988 | 4061 | if (map == NULL) { |
c93552c4 DB |
4062 | verbose(env, "kernel subsystem misconfigured verifier\n"); |
4063 | return -EINVAL; | |
4064 | } | |
4065 | ||
591fe988 DB |
4066 | /* In case of read-only, some additional restrictions |
4067 | * need to be applied in order to prevent altering the | |
4068 | * state of the map from program side. | |
4069 | */ | |
4070 | if ((map->map_flags & BPF_F_RDONLY_PROG) && | |
4071 | (func_id == BPF_FUNC_map_delete_elem || | |
4072 | func_id == BPF_FUNC_map_update_elem || | |
4073 | func_id == BPF_FUNC_map_push_elem || | |
4074 | func_id == BPF_FUNC_map_pop_elem)) { | |
4075 | verbose(env, "write into map forbidden\n"); | |
4076 | return -EACCES; | |
4077 | } | |
4078 | ||
c93552c4 DB |
4079 | if (!BPF_MAP_PTR(aux->map_state)) |
4080 | bpf_map_ptr_store(aux, meta->map_ptr, | |
4081 | meta->map_ptr->unpriv_array); | |
4082 | else if (BPF_MAP_PTR(aux->map_state) != meta->map_ptr) | |
4083 | bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON, | |
4084 | meta->map_ptr->unpriv_array); | |
4085 | return 0; | |
4086 | } | |
4087 | ||
fd978bf7 JS |
4088 | static int check_reference_leak(struct bpf_verifier_env *env) |
4089 | { | |
4090 | struct bpf_func_state *state = cur_func(env); | |
4091 | int i; | |
4092 | ||
4093 | for (i = 0; i < state->acquired_refs; i++) { | |
4094 | verbose(env, "Unreleased reference id=%d alloc_insn=%d\n", | |
4095 | state->refs[i].id, state->refs[i].insn_idx); | |
4096 | } | |
4097 | return state->acquired_refs ? -EINVAL : 0; | |
4098 | } | |
4099 | ||
f4d7e40a | 4100 | static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn_idx) |
17a52670 | 4101 | { |
17a52670 | 4102 | const struct bpf_func_proto *fn = NULL; |
638f5b90 | 4103 | struct bpf_reg_state *regs; |
33ff9823 | 4104 | struct bpf_call_arg_meta meta; |
969bf05e | 4105 | bool changes_data; |
17a52670 AS |
4106 | int i, err; |
4107 | ||
4108 | /* find function prototype */ | |
4109 | if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) { | |
61bd5218 JK |
4110 | verbose(env, "invalid func %s#%d\n", func_id_name(func_id), |
4111 | func_id); | |
17a52670 AS |
4112 | return -EINVAL; |
4113 | } | |
4114 | ||
00176a34 | 4115 | if (env->ops->get_func_proto) |
5e43f899 | 4116 | fn = env->ops->get_func_proto(func_id, env->prog); |
17a52670 | 4117 | if (!fn) { |
61bd5218 JK |
4118 | verbose(env, "unknown func %s#%d\n", func_id_name(func_id), |
4119 | func_id); | |
17a52670 AS |
4120 | return -EINVAL; |
4121 | } | |
4122 | ||
4123 | /* eBPF programs must be GPL compatible to use GPL-ed functions */ | |
24701ece | 4124 | if (!env->prog->gpl_compatible && fn->gpl_only) { |
3fe2867c | 4125 | verbose(env, "cannot call GPL-restricted function from non-GPL compatible program\n"); |
17a52670 AS |
4126 | return -EINVAL; |
4127 | } | |
4128 | ||
04514d13 | 4129 | /* With LD_ABS/IND some JITs save/restore skb from r1. */ |
17bedab2 | 4130 | changes_data = bpf_helper_changes_pkt_data(fn->func); |
04514d13 DB |
4131 | if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) { |
4132 | verbose(env, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n", | |
4133 | func_id_name(func_id), func_id); | |
4134 | return -EINVAL; | |
4135 | } | |
969bf05e | 4136 | |
33ff9823 | 4137 | memset(&meta, 0, sizeof(meta)); |
36bbef52 | 4138 | meta.pkt_access = fn->pkt_access; |
33ff9823 | 4139 | |
1b986589 | 4140 | err = check_func_proto(fn, func_id); |
435faee1 | 4141 | if (err) { |
61bd5218 | 4142 | verbose(env, "kernel subsystem misconfigured func %s#%d\n", |
ebb676da | 4143 | func_id_name(func_id), func_id); |
435faee1 DB |
4144 | return err; |
4145 | } | |
4146 | ||
d83525ca | 4147 | meta.func_id = func_id; |
17a52670 | 4148 | /* check args */ |
a7658e1a AS |
4149 | for (i = 0; i < 5; i++) { |
4150 | if (fn->arg_type[i] == ARG_PTR_TO_BTF_ID) { | |
4151 | if (!fn->btf_id[i]) | |
4152 | fn->btf_id[i] = btf_resolve_helper_id(&env->log, fn->func, i); | |
4153 | meta.btf_id = fn->btf_id[i]; | |
4154 | } | |
4155 | err = check_func_arg(env, BPF_REG_1 + i, fn->arg_type[i], &meta); | |
4156 | if (err) | |
4157 | return err; | |
4158 | } | |
17a52670 | 4159 | |
c93552c4 DB |
4160 | err = record_func_map(env, &meta, func_id, insn_idx); |
4161 | if (err) | |
4162 | return err; | |
4163 | ||
435faee1 DB |
4164 | /* Mark slots with STACK_MISC in case of raw mode, stack offset |
4165 | * is inferred from register state. | |
4166 | */ | |
4167 | for (i = 0; i < meta.access_size; i++) { | |
ca369602 DB |
4168 | err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B, |
4169 | BPF_WRITE, -1, false); | |
435faee1 DB |
4170 | if (err) |
4171 | return err; | |
4172 | } | |
4173 | ||
fd978bf7 JS |
4174 | if (func_id == BPF_FUNC_tail_call) { |
4175 | err = check_reference_leak(env); | |
4176 | if (err) { | |
4177 | verbose(env, "tail_call would lead to reference leak\n"); | |
4178 | return err; | |
4179 | } | |
4180 | } else if (is_release_function(func_id)) { | |
1b986589 | 4181 | err = release_reference(env, meta.ref_obj_id); |
46f8bc92 MKL |
4182 | if (err) { |
4183 | verbose(env, "func %s#%d reference has not been acquired before\n", | |
4184 | func_id_name(func_id), func_id); | |
fd978bf7 | 4185 | return err; |
46f8bc92 | 4186 | } |
fd978bf7 JS |
4187 | } |
4188 | ||
638f5b90 | 4189 | regs = cur_regs(env); |
cd339431 RG |
4190 | |
4191 | /* check that flags argument in get_local_storage(map, flags) is 0, | |
4192 | * this is required because get_local_storage() can't return an error. | |
4193 | */ | |
4194 | if (func_id == BPF_FUNC_get_local_storage && | |
4195 | !register_is_null(®s[BPF_REG_2])) { | |
4196 | verbose(env, "get_local_storage() doesn't support non-zero flags\n"); | |
4197 | return -EINVAL; | |
4198 | } | |
4199 | ||
17a52670 | 4200 | /* reset caller saved regs */ |
dc503a8a | 4201 | for (i = 0; i < CALLER_SAVED_REGS; i++) { |
61bd5218 | 4202 | mark_reg_not_init(env, regs, caller_saved[i]); |
dc503a8a EC |
4203 | check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK); |
4204 | } | |
17a52670 | 4205 | |
5327ed3d JW |
4206 | /* helper call returns 64-bit value. */ |
4207 | regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG; | |
4208 | ||
dc503a8a | 4209 | /* update return register (already marked as written above) */ |
17a52670 | 4210 | if (fn->ret_type == RET_INTEGER) { |
f1174f77 | 4211 | /* sets type to SCALAR_VALUE */ |
61bd5218 | 4212 | mark_reg_unknown(env, regs, BPF_REG_0); |
17a52670 AS |
4213 | } else if (fn->ret_type == RET_VOID) { |
4214 | regs[BPF_REG_0].type = NOT_INIT; | |
3e6a4b3e RG |
4215 | } else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL || |
4216 | fn->ret_type == RET_PTR_TO_MAP_VALUE) { | |
f1174f77 | 4217 | /* There is no offset yet applied, variable or fixed */ |
61bd5218 | 4218 | mark_reg_known_zero(env, regs, BPF_REG_0); |
17a52670 AS |
4219 | /* remember map_ptr, so that check_map_access() |
4220 | * can check 'value_size' boundary of memory access | |
4221 | * to map element returned from bpf_map_lookup_elem() | |
4222 | */ | |
33ff9823 | 4223 | if (meta.map_ptr == NULL) { |
61bd5218 JK |
4224 | verbose(env, |
4225 | "kernel subsystem misconfigured verifier\n"); | |
17a52670 AS |
4226 | return -EINVAL; |
4227 | } | |
33ff9823 | 4228 | regs[BPF_REG_0].map_ptr = meta.map_ptr; |
4d31f301 DB |
4229 | if (fn->ret_type == RET_PTR_TO_MAP_VALUE) { |
4230 | regs[BPF_REG_0].type = PTR_TO_MAP_VALUE; | |
e16d2f1a AS |
4231 | if (map_value_has_spin_lock(meta.map_ptr)) |
4232 | regs[BPF_REG_0].id = ++env->id_gen; | |
4d31f301 DB |
4233 | } else { |
4234 | regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL; | |
4235 | regs[BPF_REG_0].id = ++env->id_gen; | |
4236 | } | |
c64b7983 JS |
4237 | } else if (fn->ret_type == RET_PTR_TO_SOCKET_OR_NULL) { |
4238 | mark_reg_known_zero(env, regs, BPF_REG_0); | |
4239 | regs[BPF_REG_0].type = PTR_TO_SOCKET_OR_NULL; | |
0f3adc28 | 4240 | regs[BPF_REG_0].id = ++env->id_gen; |
85a51f8c LB |
4241 | } else if (fn->ret_type == RET_PTR_TO_SOCK_COMMON_OR_NULL) { |
4242 | mark_reg_known_zero(env, regs, BPF_REG_0); | |
4243 | regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON_OR_NULL; | |
4244 | regs[BPF_REG_0].id = ++env->id_gen; | |
655a51e5 MKL |
4245 | } else if (fn->ret_type == RET_PTR_TO_TCP_SOCK_OR_NULL) { |
4246 | mark_reg_known_zero(env, regs, BPF_REG_0); | |
4247 | regs[BPF_REG_0].type = PTR_TO_TCP_SOCK_OR_NULL; | |
4248 | regs[BPF_REG_0].id = ++env->id_gen; | |
17a52670 | 4249 | } else { |
61bd5218 | 4250 | verbose(env, "unknown return type %d of func %s#%d\n", |
ebb676da | 4251 | fn->ret_type, func_id_name(func_id), func_id); |
17a52670 AS |
4252 | return -EINVAL; |
4253 | } | |
04fd61ab | 4254 | |
0f3adc28 | 4255 | if (is_ptr_cast_function(func_id)) { |
1b986589 MKL |
4256 | /* For release_reference() */ |
4257 | regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id; | |
0f3adc28 LB |
4258 | } else if (is_acquire_function(func_id)) { |
4259 | int id = acquire_reference_state(env, insn_idx); | |
4260 | ||
4261 | if (id < 0) | |
4262 | return id; | |
4263 | /* For mark_ptr_or_null_reg() */ | |
4264 | regs[BPF_REG_0].id = id; | |
4265 | /* For release_reference() */ | |
4266 | regs[BPF_REG_0].ref_obj_id = id; | |
4267 | } | |
1b986589 | 4268 | |
849fa506 YS |
4269 | do_refine_retval_range(regs, fn->ret_type, func_id, &meta); |
4270 | ||
61bd5218 | 4271 | err = check_map_func_compatibility(env, meta.map_ptr, func_id); |
35578d79 KX |
4272 | if (err) |
4273 | return err; | |
04fd61ab | 4274 | |
c195651e YS |
4275 | if (func_id == BPF_FUNC_get_stack && !env->prog->has_callchain_buf) { |
4276 | const char *err_str; | |
4277 | ||
4278 | #ifdef CONFIG_PERF_EVENTS | |
4279 | err = get_callchain_buffers(sysctl_perf_event_max_stack); | |
4280 | err_str = "cannot get callchain buffer for func %s#%d\n"; | |
4281 | #else | |
4282 | err = -ENOTSUPP; | |
4283 | err_str = "func %s#%d not supported without CONFIG_PERF_EVENTS\n"; | |
4284 | #endif | |
4285 | if (err) { | |
4286 | verbose(env, err_str, func_id_name(func_id), func_id); | |
4287 | return err; | |
4288 | } | |
4289 | ||
4290 | env->prog->has_callchain_buf = true; | |
4291 | } | |
4292 | ||
969bf05e AS |
4293 | if (changes_data) |
4294 | clear_all_pkt_pointers(env); | |
4295 | return 0; | |
4296 | } | |
4297 | ||
b03c9f9f EC |
4298 | static bool signed_add_overflows(s64 a, s64 b) |
4299 | { | |
4300 | /* Do the add in u64, where overflow is well-defined */ | |
4301 | s64 res = (s64)((u64)a + (u64)b); | |
4302 | ||
4303 | if (b < 0) | |
4304 | return res > a; | |
4305 | return res < a; | |
4306 | } | |
4307 | ||
4308 | static bool signed_sub_overflows(s64 a, s64 b) | |
4309 | { | |
4310 | /* Do the sub in u64, where overflow is well-defined */ | |
4311 | s64 res = (s64)((u64)a - (u64)b); | |
4312 | ||
4313 | if (b < 0) | |
4314 | return res < a; | |
4315 | return res > a; | |
969bf05e AS |
4316 | } |
4317 | ||
bb7f0f98 AS |
4318 | static bool check_reg_sane_offset(struct bpf_verifier_env *env, |
4319 | const struct bpf_reg_state *reg, | |
4320 | enum bpf_reg_type type) | |
4321 | { | |
4322 | bool known = tnum_is_const(reg->var_off); | |
4323 | s64 val = reg->var_off.value; | |
4324 | s64 smin = reg->smin_value; | |
4325 | ||
4326 | if (known && (val >= BPF_MAX_VAR_OFF || val <= -BPF_MAX_VAR_OFF)) { | |
4327 | verbose(env, "math between %s pointer and %lld is not allowed\n", | |
4328 | reg_type_str[type], val); | |
4329 | return false; | |
4330 | } | |
4331 | ||
4332 | if (reg->off >= BPF_MAX_VAR_OFF || reg->off <= -BPF_MAX_VAR_OFF) { | |
4333 | verbose(env, "%s pointer offset %d is not allowed\n", | |
4334 | reg_type_str[type], reg->off); | |
4335 | return false; | |
4336 | } | |
4337 | ||
4338 | if (smin == S64_MIN) { | |
4339 | verbose(env, "math between %s pointer and register with unbounded min value is not allowed\n", | |
4340 | reg_type_str[type]); | |
4341 | return false; | |
4342 | } | |
4343 | ||
4344 | if (smin >= BPF_MAX_VAR_OFF || smin <= -BPF_MAX_VAR_OFF) { | |
4345 | verbose(env, "value %lld makes %s pointer be out of bounds\n", | |
4346 | smin, reg_type_str[type]); | |
4347 | return false; | |
4348 | } | |
4349 | ||
4350 | return true; | |
4351 | } | |
4352 | ||
979d63d5 DB |
4353 | static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env) |
4354 | { | |
4355 | return &env->insn_aux_data[env->insn_idx]; | |
4356 | } | |
4357 | ||
4358 | static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, | |
4359 | u32 *ptr_limit, u8 opcode, bool off_is_neg) | |
4360 | { | |
4361 | bool mask_to_left = (opcode == BPF_ADD && off_is_neg) || | |
4362 | (opcode == BPF_SUB && !off_is_neg); | |
4363 | u32 off; | |
4364 | ||
4365 | switch (ptr_reg->type) { | |
4366 | case PTR_TO_STACK: | |
088ec26d AI |
4367 | /* Indirect variable offset stack access is prohibited in |
4368 | * unprivileged mode so it's not handled here. | |
4369 | */ | |
979d63d5 DB |
4370 | off = ptr_reg->off + ptr_reg->var_off.value; |
4371 | if (mask_to_left) | |
4372 | *ptr_limit = MAX_BPF_STACK + off; | |
4373 | else | |
4374 | *ptr_limit = -off; | |
4375 | return 0; | |
4376 | case PTR_TO_MAP_VALUE: | |
4377 | if (mask_to_left) { | |
4378 | *ptr_limit = ptr_reg->umax_value + ptr_reg->off; | |
4379 | } else { | |
4380 | off = ptr_reg->smin_value + ptr_reg->off; | |
4381 | *ptr_limit = ptr_reg->map_ptr->value_size - off; | |
4382 | } | |
4383 | return 0; | |
4384 | default: | |
4385 | return -EINVAL; | |
4386 | } | |
4387 | } | |
4388 | ||
d3bd7413 DB |
4389 | static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env, |
4390 | const struct bpf_insn *insn) | |
4391 | { | |
4392 | return env->allow_ptr_leaks || BPF_SRC(insn->code) == BPF_K; | |
4393 | } | |
4394 | ||
4395 | static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux, | |
4396 | u32 alu_state, u32 alu_limit) | |
4397 | { | |
4398 | /* If we arrived here from different branches with different | |
4399 | * state or limits to sanitize, then this won't work. | |
4400 | */ | |
4401 | if (aux->alu_state && | |
4402 | (aux->alu_state != alu_state || | |
4403 | aux->alu_limit != alu_limit)) | |
4404 | return -EACCES; | |
4405 | ||
4406 | /* Corresponding fixup done in fixup_bpf_calls(). */ | |
4407 | aux->alu_state = alu_state; | |
4408 | aux->alu_limit = alu_limit; | |
4409 | return 0; | |
4410 | } | |
4411 | ||
4412 | static int sanitize_val_alu(struct bpf_verifier_env *env, | |
4413 | struct bpf_insn *insn) | |
4414 | { | |
4415 | struct bpf_insn_aux_data *aux = cur_aux(env); | |
4416 | ||
4417 | if (can_skip_alu_sanitation(env, insn)) | |
4418 | return 0; | |
4419 | ||
4420 | return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0); | |
4421 | } | |
4422 | ||
979d63d5 DB |
4423 | static int sanitize_ptr_alu(struct bpf_verifier_env *env, |
4424 | struct bpf_insn *insn, | |
4425 | const struct bpf_reg_state *ptr_reg, | |
4426 | struct bpf_reg_state *dst_reg, | |
4427 | bool off_is_neg) | |
4428 | { | |
4429 | struct bpf_verifier_state *vstate = env->cur_state; | |
4430 | struct bpf_insn_aux_data *aux = cur_aux(env); | |
4431 | bool ptr_is_dst_reg = ptr_reg == dst_reg; | |
4432 | u8 opcode = BPF_OP(insn->code); | |
4433 | u32 alu_state, alu_limit; | |
4434 | struct bpf_reg_state tmp; | |
4435 | bool ret; | |
4436 | ||
d3bd7413 | 4437 | if (can_skip_alu_sanitation(env, insn)) |
979d63d5 DB |
4438 | return 0; |
4439 | ||
4440 | /* We already marked aux for masking from non-speculative | |
4441 | * paths, thus we got here in the first place. We only care | |
4442 | * to explore bad access from here. | |
4443 | */ | |
4444 | if (vstate->speculative) | |
4445 | goto do_sim; | |
4446 | ||
4447 | alu_state = off_is_neg ? BPF_ALU_NEG_VALUE : 0; | |
4448 | alu_state |= ptr_is_dst_reg ? | |
4449 | BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST; | |
4450 | ||
4451 | if (retrieve_ptr_limit(ptr_reg, &alu_limit, opcode, off_is_neg)) | |
4452 | return 0; | |
d3bd7413 | 4453 | if (update_alu_sanitation_state(aux, alu_state, alu_limit)) |
979d63d5 | 4454 | return -EACCES; |
979d63d5 DB |
4455 | do_sim: |
4456 | /* Simulate and find potential out-of-bounds access under | |
4457 | * speculative execution from truncation as a result of | |
4458 | * masking when off was not within expected range. If off | |
4459 | * sits in dst, then we temporarily need to move ptr there | |
4460 | * to simulate dst (== 0) +/-= ptr. Needed, for example, | |
4461 | * for cases where we use K-based arithmetic in one direction | |
4462 | * and truncated reg-based in the other in order to explore | |
4463 | * bad access. | |
4464 | */ | |
4465 | if (!ptr_is_dst_reg) { | |
4466 | tmp = *dst_reg; | |
4467 | *dst_reg = *ptr_reg; | |
4468 | } | |
4469 | ret = push_stack(env, env->insn_idx + 1, env->insn_idx, true); | |
0803278b | 4470 | if (!ptr_is_dst_reg && ret) |
979d63d5 DB |
4471 | *dst_reg = tmp; |
4472 | return !ret ? -EFAULT : 0; | |
4473 | } | |
4474 | ||
f1174f77 | 4475 | /* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off. |
f1174f77 EC |
4476 | * Caller should also handle BPF_MOV case separately. |
4477 | * If we return -EACCES, caller may want to try again treating pointer as a | |
4478 | * scalar. So we only emit a diagnostic if !env->allow_ptr_leaks. | |
4479 | */ | |
4480 | static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, | |
4481 | struct bpf_insn *insn, | |
4482 | const struct bpf_reg_state *ptr_reg, | |
4483 | const struct bpf_reg_state *off_reg) | |
969bf05e | 4484 | { |
f4d7e40a AS |
4485 | struct bpf_verifier_state *vstate = env->cur_state; |
4486 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
4487 | struct bpf_reg_state *regs = state->regs, *dst_reg; | |
f1174f77 | 4488 | bool known = tnum_is_const(off_reg->var_off); |
b03c9f9f EC |
4489 | s64 smin_val = off_reg->smin_value, smax_val = off_reg->smax_value, |
4490 | smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value; | |
4491 | u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value, | |
4492 | umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value; | |
9d7eceed | 4493 | u32 dst = insn->dst_reg, src = insn->src_reg; |
969bf05e | 4494 | u8 opcode = BPF_OP(insn->code); |
979d63d5 | 4495 | int ret; |
969bf05e | 4496 | |
f1174f77 | 4497 | dst_reg = ®s[dst]; |
969bf05e | 4498 | |
6f16101e DB |
4499 | if ((known && (smin_val != smax_val || umin_val != umax_val)) || |
4500 | smin_val > smax_val || umin_val > umax_val) { | |
4501 | /* Taint dst register if offset had invalid bounds derived from | |
4502 | * e.g. dead branches. | |
4503 | */ | |
4504 | __mark_reg_unknown(dst_reg); | |
4505 | return 0; | |
f1174f77 EC |
4506 | } |
4507 | ||
4508 | if (BPF_CLASS(insn->code) != BPF_ALU64) { | |
4509 | /* 32-bit ALU ops on pointers produce (meaningless) scalars */ | |
82abbf8d AS |
4510 | verbose(env, |
4511 | "R%d 32-bit pointer arithmetic prohibited\n", | |
4512 | dst); | |
f1174f77 | 4513 | return -EACCES; |
969bf05e AS |
4514 | } |
4515 | ||
aad2eeaf JS |
4516 | switch (ptr_reg->type) { |
4517 | case PTR_TO_MAP_VALUE_OR_NULL: | |
4518 | verbose(env, "R%d pointer arithmetic on %s prohibited, null-check it first\n", | |
4519 | dst, reg_type_str[ptr_reg->type]); | |
f1174f77 | 4520 | return -EACCES; |
aad2eeaf JS |
4521 | case CONST_PTR_TO_MAP: |
4522 | case PTR_TO_PACKET_END: | |
c64b7983 JS |
4523 | case PTR_TO_SOCKET: |
4524 | case PTR_TO_SOCKET_OR_NULL: | |
46f8bc92 MKL |
4525 | case PTR_TO_SOCK_COMMON: |
4526 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
655a51e5 MKL |
4527 | case PTR_TO_TCP_SOCK: |
4528 | case PTR_TO_TCP_SOCK_OR_NULL: | |
fada7fdc | 4529 | case PTR_TO_XDP_SOCK: |
aad2eeaf JS |
4530 | verbose(env, "R%d pointer arithmetic on %s prohibited\n", |
4531 | dst, reg_type_str[ptr_reg->type]); | |
f1174f77 | 4532 | return -EACCES; |
9d7eceed DB |
4533 | case PTR_TO_MAP_VALUE: |
4534 | if (!env->allow_ptr_leaks && !known && (smin_val < 0) != (smax_val < 0)) { | |
4535 | verbose(env, "R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n", | |
4536 | off_reg == dst_reg ? dst : src); | |
4537 | return -EACCES; | |
4538 | } | |
4539 | /* fall-through */ | |
aad2eeaf JS |
4540 | default: |
4541 | break; | |
f1174f77 EC |
4542 | } |
4543 | ||
4544 | /* In case of 'scalar += pointer', dst_reg inherits pointer type and id. | |
4545 | * The id may be overwritten later if we create a new variable offset. | |
969bf05e | 4546 | */ |
f1174f77 EC |
4547 | dst_reg->type = ptr_reg->type; |
4548 | dst_reg->id = ptr_reg->id; | |
969bf05e | 4549 | |
bb7f0f98 AS |
4550 | if (!check_reg_sane_offset(env, off_reg, ptr_reg->type) || |
4551 | !check_reg_sane_offset(env, ptr_reg, ptr_reg->type)) | |
4552 | return -EINVAL; | |
4553 | ||
f1174f77 EC |
4554 | switch (opcode) { |
4555 | case BPF_ADD: | |
979d63d5 DB |
4556 | ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0); |
4557 | if (ret < 0) { | |
4558 | verbose(env, "R%d tried to add from different maps or paths\n", dst); | |
4559 | return ret; | |
4560 | } | |
f1174f77 EC |
4561 | /* We can take a fixed offset as long as it doesn't overflow |
4562 | * the s32 'off' field | |
969bf05e | 4563 | */ |
b03c9f9f EC |
4564 | if (known && (ptr_reg->off + smin_val == |
4565 | (s64)(s32)(ptr_reg->off + smin_val))) { | |
f1174f77 | 4566 | /* pointer += K. Accumulate it into fixed offset */ |
b03c9f9f EC |
4567 | dst_reg->smin_value = smin_ptr; |
4568 | dst_reg->smax_value = smax_ptr; | |
4569 | dst_reg->umin_value = umin_ptr; | |
4570 | dst_reg->umax_value = umax_ptr; | |
f1174f77 | 4571 | dst_reg->var_off = ptr_reg->var_off; |
b03c9f9f | 4572 | dst_reg->off = ptr_reg->off + smin_val; |
0962590e | 4573 | dst_reg->raw = ptr_reg->raw; |
f1174f77 EC |
4574 | break; |
4575 | } | |
f1174f77 EC |
4576 | /* A new variable offset is created. Note that off_reg->off |
4577 | * == 0, since it's a scalar. | |
4578 | * dst_reg gets the pointer type and since some positive | |
4579 | * integer value was added to the pointer, give it a new 'id' | |
4580 | * if it's a PTR_TO_PACKET. | |
4581 | * this creates a new 'base' pointer, off_reg (variable) gets | |
4582 | * added into the variable offset, and we copy the fixed offset | |
4583 | * from ptr_reg. | |
969bf05e | 4584 | */ |
b03c9f9f EC |
4585 | if (signed_add_overflows(smin_ptr, smin_val) || |
4586 | signed_add_overflows(smax_ptr, smax_val)) { | |
4587 | dst_reg->smin_value = S64_MIN; | |
4588 | dst_reg->smax_value = S64_MAX; | |
4589 | } else { | |
4590 | dst_reg->smin_value = smin_ptr + smin_val; | |
4591 | dst_reg->smax_value = smax_ptr + smax_val; | |
4592 | } | |
4593 | if (umin_ptr + umin_val < umin_ptr || | |
4594 | umax_ptr + umax_val < umax_ptr) { | |
4595 | dst_reg->umin_value = 0; | |
4596 | dst_reg->umax_value = U64_MAX; | |
4597 | } else { | |
4598 | dst_reg->umin_value = umin_ptr + umin_val; | |
4599 | dst_reg->umax_value = umax_ptr + umax_val; | |
4600 | } | |
f1174f77 EC |
4601 | dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off); |
4602 | dst_reg->off = ptr_reg->off; | |
0962590e | 4603 | dst_reg->raw = ptr_reg->raw; |
de8f3a83 | 4604 | if (reg_is_pkt_pointer(ptr_reg)) { |
f1174f77 EC |
4605 | dst_reg->id = ++env->id_gen; |
4606 | /* something was added to pkt_ptr, set range to zero */ | |
0962590e | 4607 | dst_reg->raw = 0; |
f1174f77 EC |
4608 | } |
4609 | break; | |
4610 | case BPF_SUB: | |
979d63d5 DB |
4611 | ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0); |
4612 | if (ret < 0) { | |
4613 | verbose(env, "R%d tried to sub from different maps or paths\n", dst); | |
4614 | return ret; | |
4615 | } | |
f1174f77 EC |
4616 | if (dst_reg == off_reg) { |
4617 | /* scalar -= pointer. Creates an unknown scalar */ | |
82abbf8d AS |
4618 | verbose(env, "R%d tried to subtract pointer from scalar\n", |
4619 | dst); | |
f1174f77 EC |
4620 | return -EACCES; |
4621 | } | |
4622 | /* We don't allow subtraction from FP, because (according to | |
4623 | * test_verifier.c test "invalid fp arithmetic", JITs might not | |
4624 | * be able to deal with it. | |
969bf05e | 4625 | */ |
f1174f77 | 4626 | if (ptr_reg->type == PTR_TO_STACK) { |
82abbf8d AS |
4627 | verbose(env, "R%d subtraction from stack pointer prohibited\n", |
4628 | dst); | |
f1174f77 EC |
4629 | return -EACCES; |
4630 | } | |
b03c9f9f EC |
4631 | if (known && (ptr_reg->off - smin_val == |
4632 | (s64)(s32)(ptr_reg->off - smin_val))) { | |
f1174f77 | 4633 | /* pointer -= K. Subtract it from fixed offset */ |
b03c9f9f EC |
4634 | dst_reg->smin_value = smin_ptr; |
4635 | dst_reg->smax_value = smax_ptr; | |
4636 | dst_reg->umin_value = umin_ptr; | |
4637 | dst_reg->umax_value = umax_ptr; | |
f1174f77 EC |
4638 | dst_reg->var_off = ptr_reg->var_off; |
4639 | dst_reg->id = ptr_reg->id; | |
b03c9f9f | 4640 | dst_reg->off = ptr_reg->off - smin_val; |
0962590e | 4641 | dst_reg->raw = ptr_reg->raw; |
f1174f77 EC |
4642 | break; |
4643 | } | |
f1174f77 EC |
4644 | /* A new variable offset is created. If the subtrahend is known |
4645 | * nonnegative, then any reg->range we had before is still good. | |
969bf05e | 4646 | */ |
b03c9f9f EC |
4647 | if (signed_sub_overflows(smin_ptr, smax_val) || |
4648 | signed_sub_overflows(smax_ptr, smin_val)) { | |
4649 | /* Overflow possible, we know nothing */ | |
4650 | dst_reg->smin_value = S64_MIN; | |
4651 | dst_reg->smax_value = S64_MAX; | |
4652 | } else { | |
4653 | dst_reg->smin_value = smin_ptr - smax_val; | |
4654 | dst_reg->smax_value = smax_ptr - smin_val; | |
4655 | } | |
4656 | if (umin_ptr < umax_val) { | |
4657 | /* Overflow possible, we know nothing */ | |
4658 | dst_reg->umin_value = 0; | |
4659 | dst_reg->umax_value = U64_MAX; | |
4660 | } else { | |
4661 | /* Cannot overflow (as long as bounds are consistent) */ | |
4662 | dst_reg->umin_value = umin_ptr - umax_val; | |
4663 | dst_reg->umax_value = umax_ptr - umin_val; | |
4664 | } | |
f1174f77 EC |
4665 | dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off); |
4666 | dst_reg->off = ptr_reg->off; | |
0962590e | 4667 | dst_reg->raw = ptr_reg->raw; |
de8f3a83 | 4668 | if (reg_is_pkt_pointer(ptr_reg)) { |
f1174f77 EC |
4669 | dst_reg->id = ++env->id_gen; |
4670 | /* something was added to pkt_ptr, set range to zero */ | |
b03c9f9f | 4671 | if (smin_val < 0) |
0962590e | 4672 | dst_reg->raw = 0; |
43188702 | 4673 | } |
f1174f77 EC |
4674 | break; |
4675 | case BPF_AND: | |
4676 | case BPF_OR: | |
4677 | case BPF_XOR: | |
82abbf8d AS |
4678 | /* bitwise ops on pointers are troublesome, prohibit. */ |
4679 | verbose(env, "R%d bitwise operator %s on pointer prohibited\n", | |
4680 | dst, bpf_alu_string[opcode >> 4]); | |
f1174f77 EC |
4681 | return -EACCES; |
4682 | default: | |
4683 | /* other operators (e.g. MUL,LSH) produce non-pointer results */ | |
82abbf8d AS |
4684 | verbose(env, "R%d pointer arithmetic with %s operator prohibited\n", |
4685 | dst, bpf_alu_string[opcode >> 4]); | |
f1174f77 | 4686 | return -EACCES; |
43188702 JF |
4687 | } |
4688 | ||
bb7f0f98 AS |
4689 | if (!check_reg_sane_offset(env, dst_reg, ptr_reg->type)) |
4690 | return -EINVAL; | |
4691 | ||
b03c9f9f EC |
4692 | __update_reg_bounds(dst_reg); |
4693 | __reg_deduce_bounds(dst_reg); | |
4694 | __reg_bound_offset(dst_reg); | |
0d6303db DB |
4695 | |
4696 | /* For unprivileged we require that resulting offset must be in bounds | |
4697 | * in order to be able to sanitize access later on. | |
4698 | */ | |
e4298d25 DB |
4699 | if (!env->allow_ptr_leaks) { |
4700 | if (dst_reg->type == PTR_TO_MAP_VALUE && | |
4701 | check_map_access(env, dst, dst_reg->off, 1, false)) { | |
4702 | verbose(env, "R%d pointer arithmetic of map value goes out of range, " | |
4703 | "prohibited for !root\n", dst); | |
4704 | return -EACCES; | |
4705 | } else if (dst_reg->type == PTR_TO_STACK && | |
4706 | check_stack_access(env, dst_reg, dst_reg->off + | |
4707 | dst_reg->var_off.value, 1)) { | |
4708 | verbose(env, "R%d stack pointer arithmetic goes out of range, " | |
4709 | "prohibited for !root\n", dst); | |
4710 | return -EACCES; | |
4711 | } | |
0d6303db DB |
4712 | } |
4713 | ||
43188702 JF |
4714 | return 0; |
4715 | } | |
4716 | ||
468f6eaf JH |
4717 | /* WARNING: This function does calculations on 64-bit values, but the actual |
4718 | * execution may occur on 32-bit values. Therefore, things like bitshifts | |
4719 | * need extra checks in the 32-bit case. | |
4720 | */ | |
f1174f77 EC |
4721 | static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, |
4722 | struct bpf_insn *insn, | |
4723 | struct bpf_reg_state *dst_reg, | |
4724 | struct bpf_reg_state src_reg) | |
969bf05e | 4725 | { |
638f5b90 | 4726 | struct bpf_reg_state *regs = cur_regs(env); |
48461135 | 4727 | u8 opcode = BPF_OP(insn->code); |
f1174f77 | 4728 | bool src_known, dst_known; |
b03c9f9f EC |
4729 | s64 smin_val, smax_val; |
4730 | u64 umin_val, umax_val; | |
468f6eaf | 4731 | u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32; |
d3bd7413 DB |
4732 | u32 dst = insn->dst_reg; |
4733 | int ret; | |
48461135 | 4734 | |
b799207e JH |
4735 | if (insn_bitness == 32) { |
4736 | /* Relevant for 32-bit RSH: Information can propagate towards | |
4737 | * LSB, so it isn't sufficient to only truncate the output to | |
4738 | * 32 bits. | |
4739 | */ | |
4740 | coerce_reg_to_size(dst_reg, 4); | |
4741 | coerce_reg_to_size(&src_reg, 4); | |
4742 | } | |
4743 | ||
b03c9f9f EC |
4744 | smin_val = src_reg.smin_value; |
4745 | smax_val = src_reg.smax_value; | |
4746 | umin_val = src_reg.umin_value; | |
4747 | umax_val = src_reg.umax_value; | |
f1174f77 EC |
4748 | src_known = tnum_is_const(src_reg.var_off); |
4749 | dst_known = tnum_is_const(dst_reg->var_off); | |
f23cc643 | 4750 | |
6f16101e DB |
4751 | if ((src_known && (smin_val != smax_val || umin_val != umax_val)) || |
4752 | smin_val > smax_val || umin_val > umax_val) { | |
4753 | /* Taint dst register if offset had invalid bounds derived from | |
4754 | * e.g. dead branches. | |
4755 | */ | |
4756 | __mark_reg_unknown(dst_reg); | |
4757 | return 0; | |
4758 | } | |
4759 | ||
bb7f0f98 AS |
4760 | if (!src_known && |
4761 | opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) { | |
4762 | __mark_reg_unknown(dst_reg); | |
4763 | return 0; | |
4764 | } | |
4765 | ||
48461135 JB |
4766 | switch (opcode) { |
4767 | case BPF_ADD: | |
d3bd7413 DB |
4768 | ret = sanitize_val_alu(env, insn); |
4769 | if (ret < 0) { | |
4770 | verbose(env, "R%d tried to add from different pointers or scalars\n", dst); | |
4771 | return ret; | |
4772 | } | |
b03c9f9f EC |
4773 | if (signed_add_overflows(dst_reg->smin_value, smin_val) || |
4774 | signed_add_overflows(dst_reg->smax_value, smax_val)) { | |
4775 | dst_reg->smin_value = S64_MIN; | |
4776 | dst_reg->smax_value = S64_MAX; | |
4777 | } else { | |
4778 | dst_reg->smin_value += smin_val; | |
4779 | dst_reg->smax_value += smax_val; | |
4780 | } | |
4781 | if (dst_reg->umin_value + umin_val < umin_val || | |
4782 | dst_reg->umax_value + umax_val < umax_val) { | |
4783 | dst_reg->umin_value = 0; | |
4784 | dst_reg->umax_value = U64_MAX; | |
4785 | } else { | |
4786 | dst_reg->umin_value += umin_val; | |
4787 | dst_reg->umax_value += umax_val; | |
4788 | } | |
f1174f77 | 4789 | dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off); |
48461135 JB |
4790 | break; |
4791 | case BPF_SUB: | |
d3bd7413 DB |
4792 | ret = sanitize_val_alu(env, insn); |
4793 | if (ret < 0) { | |
4794 | verbose(env, "R%d tried to sub from different pointers or scalars\n", dst); | |
4795 | return ret; | |
4796 | } | |
b03c9f9f EC |
4797 | if (signed_sub_overflows(dst_reg->smin_value, smax_val) || |
4798 | signed_sub_overflows(dst_reg->smax_value, smin_val)) { | |
4799 | /* Overflow possible, we know nothing */ | |
4800 | dst_reg->smin_value = S64_MIN; | |
4801 | dst_reg->smax_value = S64_MAX; | |
4802 | } else { | |
4803 | dst_reg->smin_value -= smax_val; | |
4804 | dst_reg->smax_value -= smin_val; | |
4805 | } | |
4806 | if (dst_reg->umin_value < umax_val) { | |
4807 | /* Overflow possible, we know nothing */ | |
4808 | dst_reg->umin_value = 0; | |
4809 | dst_reg->umax_value = U64_MAX; | |
4810 | } else { | |
4811 | /* Cannot overflow (as long as bounds are consistent) */ | |
4812 | dst_reg->umin_value -= umax_val; | |
4813 | dst_reg->umax_value -= umin_val; | |
4814 | } | |
f1174f77 | 4815 | dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off); |
48461135 JB |
4816 | break; |
4817 | case BPF_MUL: | |
b03c9f9f EC |
4818 | dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off); |
4819 | if (smin_val < 0 || dst_reg->smin_value < 0) { | |
f1174f77 | 4820 | /* Ain't nobody got time to multiply that sign */ |
b03c9f9f EC |
4821 | __mark_reg_unbounded(dst_reg); |
4822 | __update_reg_bounds(dst_reg); | |
f1174f77 EC |
4823 | break; |
4824 | } | |
b03c9f9f EC |
4825 | /* Both values are positive, so we can work with unsigned and |
4826 | * copy the result to signed (unless it exceeds S64_MAX). | |
f1174f77 | 4827 | */ |
b03c9f9f EC |
4828 | if (umax_val > U32_MAX || dst_reg->umax_value > U32_MAX) { |
4829 | /* Potential overflow, we know nothing */ | |
4830 | __mark_reg_unbounded(dst_reg); | |
4831 | /* (except what we can learn from the var_off) */ | |
4832 | __update_reg_bounds(dst_reg); | |
4833 | break; | |
4834 | } | |
4835 | dst_reg->umin_value *= umin_val; | |
4836 | dst_reg->umax_value *= umax_val; | |
4837 | if (dst_reg->umax_value > S64_MAX) { | |
4838 | /* Overflow possible, we know nothing */ | |
4839 | dst_reg->smin_value = S64_MIN; | |
4840 | dst_reg->smax_value = S64_MAX; | |
4841 | } else { | |
4842 | dst_reg->smin_value = dst_reg->umin_value; | |
4843 | dst_reg->smax_value = dst_reg->umax_value; | |
4844 | } | |
48461135 JB |
4845 | break; |
4846 | case BPF_AND: | |
f1174f77 | 4847 | if (src_known && dst_known) { |
b03c9f9f EC |
4848 | __mark_reg_known(dst_reg, dst_reg->var_off.value & |
4849 | src_reg.var_off.value); | |
f1174f77 EC |
4850 | break; |
4851 | } | |
b03c9f9f EC |
4852 | /* We get our minimum from the var_off, since that's inherently |
4853 | * bitwise. Our maximum is the minimum of the operands' maxima. | |
f23cc643 | 4854 | */ |
f1174f77 | 4855 | dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg.var_off); |
b03c9f9f EC |
4856 | dst_reg->umin_value = dst_reg->var_off.value; |
4857 | dst_reg->umax_value = min(dst_reg->umax_value, umax_val); | |
4858 | if (dst_reg->smin_value < 0 || smin_val < 0) { | |
4859 | /* Lose signed bounds when ANDing negative numbers, | |
4860 | * ain't nobody got time for that. | |
4861 | */ | |
4862 | dst_reg->smin_value = S64_MIN; | |
4863 | dst_reg->smax_value = S64_MAX; | |
4864 | } else { | |
4865 | /* ANDing two positives gives a positive, so safe to | |
4866 | * cast result into s64. | |
4867 | */ | |
4868 | dst_reg->smin_value = dst_reg->umin_value; | |
4869 | dst_reg->smax_value = dst_reg->umax_value; | |
4870 | } | |
4871 | /* We may learn something more from the var_off */ | |
4872 | __update_reg_bounds(dst_reg); | |
f1174f77 EC |
4873 | break; |
4874 | case BPF_OR: | |
4875 | if (src_known && dst_known) { | |
b03c9f9f EC |
4876 | __mark_reg_known(dst_reg, dst_reg->var_off.value | |
4877 | src_reg.var_off.value); | |
f1174f77 EC |
4878 | break; |
4879 | } | |
b03c9f9f EC |
4880 | /* We get our maximum from the var_off, and our minimum is the |
4881 | * maximum of the operands' minima | |
f1174f77 EC |
4882 | */ |
4883 | dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg.var_off); | |
b03c9f9f EC |
4884 | dst_reg->umin_value = max(dst_reg->umin_value, umin_val); |
4885 | dst_reg->umax_value = dst_reg->var_off.value | | |
4886 | dst_reg->var_off.mask; | |
4887 | if (dst_reg->smin_value < 0 || smin_val < 0) { | |
4888 | /* Lose signed bounds when ORing negative numbers, | |
4889 | * ain't nobody got time for that. | |
4890 | */ | |
4891 | dst_reg->smin_value = S64_MIN; | |
4892 | dst_reg->smax_value = S64_MAX; | |
f1174f77 | 4893 | } else { |
b03c9f9f EC |
4894 | /* ORing two positives gives a positive, so safe to |
4895 | * cast result into s64. | |
4896 | */ | |
4897 | dst_reg->smin_value = dst_reg->umin_value; | |
4898 | dst_reg->smax_value = dst_reg->umax_value; | |
f1174f77 | 4899 | } |
b03c9f9f EC |
4900 | /* We may learn something more from the var_off */ |
4901 | __update_reg_bounds(dst_reg); | |
48461135 JB |
4902 | break; |
4903 | case BPF_LSH: | |
468f6eaf JH |
4904 | if (umax_val >= insn_bitness) { |
4905 | /* Shifts greater than 31 or 63 are undefined. | |
4906 | * This includes shifts by a negative number. | |
b03c9f9f | 4907 | */ |
61bd5218 | 4908 | mark_reg_unknown(env, regs, insn->dst_reg); |
f1174f77 EC |
4909 | break; |
4910 | } | |
b03c9f9f EC |
4911 | /* We lose all sign bit information (except what we can pick |
4912 | * up from var_off) | |
48461135 | 4913 | */ |
b03c9f9f EC |
4914 | dst_reg->smin_value = S64_MIN; |
4915 | dst_reg->smax_value = S64_MAX; | |
4916 | /* If we might shift our top bit out, then we know nothing */ | |
4917 | if (dst_reg->umax_value > 1ULL << (63 - umax_val)) { | |
4918 | dst_reg->umin_value = 0; | |
4919 | dst_reg->umax_value = U64_MAX; | |
d1174416 | 4920 | } else { |
b03c9f9f EC |
4921 | dst_reg->umin_value <<= umin_val; |
4922 | dst_reg->umax_value <<= umax_val; | |
d1174416 | 4923 | } |
afbe1a5b | 4924 | dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val); |
b03c9f9f EC |
4925 | /* We may learn something more from the var_off */ |
4926 | __update_reg_bounds(dst_reg); | |
48461135 JB |
4927 | break; |
4928 | case BPF_RSH: | |
468f6eaf JH |
4929 | if (umax_val >= insn_bitness) { |
4930 | /* Shifts greater than 31 or 63 are undefined. | |
4931 | * This includes shifts by a negative number. | |
b03c9f9f | 4932 | */ |
61bd5218 | 4933 | mark_reg_unknown(env, regs, insn->dst_reg); |
f1174f77 EC |
4934 | break; |
4935 | } | |
4374f256 EC |
4936 | /* BPF_RSH is an unsigned shift. If the value in dst_reg might |
4937 | * be negative, then either: | |
4938 | * 1) src_reg might be zero, so the sign bit of the result is | |
4939 | * unknown, so we lose our signed bounds | |
4940 | * 2) it's known negative, thus the unsigned bounds capture the | |
4941 | * signed bounds | |
4942 | * 3) the signed bounds cross zero, so they tell us nothing | |
4943 | * about the result | |
4944 | * If the value in dst_reg is known nonnegative, then again the | |
4945 | * unsigned bounts capture the signed bounds. | |
4946 | * Thus, in all cases it suffices to blow away our signed bounds | |
4947 | * and rely on inferring new ones from the unsigned bounds and | |
4948 | * var_off of the result. | |
4949 | */ | |
4950 | dst_reg->smin_value = S64_MIN; | |
4951 | dst_reg->smax_value = S64_MAX; | |
afbe1a5b | 4952 | dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val); |
b03c9f9f EC |
4953 | dst_reg->umin_value >>= umax_val; |
4954 | dst_reg->umax_value >>= umin_val; | |
4955 | /* We may learn something more from the var_off */ | |
4956 | __update_reg_bounds(dst_reg); | |
48461135 | 4957 | break; |
9cbe1f5a YS |
4958 | case BPF_ARSH: |
4959 | if (umax_val >= insn_bitness) { | |
4960 | /* Shifts greater than 31 or 63 are undefined. | |
4961 | * This includes shifts by a negative number. | |
4962 | */ | |
4963 | mark_reg_unknown(env, regs, insn->dst_reg); | |
4964 | break; | |
4965 | } | |
4966 | ||
4967 | /* Upon reaching here, src_known is true and | |
4968 | * umax_val is equal to umin_val. | |
4969 | */ | |
4970 | dst_reg->smin_value >>= umin_val; | |
4971 | dst_reg->smax_value >>= umin_val; | |
4972 | dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val); | |
4973 | ||
4974 | /* blow away the dst_reg umin_value/umax_value and rely on | |
4975 | * dst_reg var_off to refine the result. | |
4976 | */ | |
4977 | dst_reg->umin_value = 0; | |
4978 | dst_reg->umax_value = U64_MAX; | |
4979 | __update_reg_bounds(dst_reg); | |
4980 | break; | |
48461135 | 4981 | default: |
61bd5218 | 4982 | mark_reg_unknown(env, regs, insn->dst_reg); |
48461135 JB |
4983 | break; |
4984 | } | |
4985 | ||
468f6eaf JH |
4986 | if (BPF_CLASS(insn->code) != BPF_ALU64) { |
4987 | /* 32-bit ALU ops are (32,32)->32 */ | |
4988 | coerce_reg_to_size(dst_reg, 4); | |
468f6eaf JH |
4989 | } |
4990 | ||
b03c9f9f EC |
4991 | __reg_deduce_bounds(dst_reg); |
4992 | __reg_bound_offset(dst_reg); | |
f1174f77 EC |
4993 | return 0; |
4994 | } | |
4995 | ||
4996 | /* Handles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max | |
4997 | * and var_off. | |
4998 | */ | |
4999 | static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, | |
5000 | struct bpf_insn *insn) | |
5001 | { | |
f4d7e40a AS |
5002 | struct bpf_verifier_state *vstate = env->cur_state; |
5003 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
5004 | struct bpf_reg_state *regs = state->regs, *dst_reg, *src_reg; | |
f1174f77 EC |
5005 | struct bpf_reg_state *ptr_reg = NULL, off_reg = {0}; |
5006 | u8 opcode = BPF_OP(insn->code); | |
b5dc0163 | 5007 | int err; |
f1174f77 EC |
5008 | |
5009 | dst_reg = ®s[insn->dst_reg]; | |
f1174f77 EC |
5010 | src_reg = NULL; |
5011 | if (dst_reg->type != SCALAR_VALUE) | |
5012 | ptr_reg = dst_reg; | |
5013 | if (BPF_SRC(insn->code) == BPF_X) { | |
5014 | src_reg = ®s[insn->src_reg]; | |
f1174f77 EC |
5015 | if (src_reg->type != SCALAR_VALUE) { |
5016 | if (dst_reg->type != SCALAR_VALUE) { | |
5017 | /* Combining two pointers by any ALU op yields | |
82abbf8d AS |
5018 | * an arbitrary scalar. Disallow all math except |
5019 | * pointer subtraction | |
f1174f77 | 5020 | */ |
dd066823 | 5021 | if (opcode == BPF_SUB && env->allow_ptr_leaks) { |
82abbf8d AS |
5022 | mark_reg_unknown(env, regs, insn->dst_reg); |
5023 | return 0; | |
f1174f77 | 5024 | } |
82abbf8d AS |
5025 | verbose(env, "R%d pointer %s pointer prohibited\n", |
5026 | insn->dst_reg, | |
5027 | bpf_alu_string[opcode >> 4]); | |
5028 | return -EACCES; | |
f1174f77 EC |
5029 | } else { |
5030 | /* scalar += pointer | |
5031 | * This is legal, but we have to reverse our | |
5032 | * src/dest handling in computing the range | |
5033 | */ | |
b5dc0163 AS |
5034 | err = mark_chain_precision(env, insn->dst_reg); |
5035 | if (err) | |
5036 | return err; | |
82abbf8d AS |
5037 | return adjust_ptr_min_max_vals(env, insn, |
5038 | src_reg, dst_reg); | |
f1174f77 EC |
5039 | } |
5040 | } else if (ptr_reg) { | |
5041 | /* pointer += scalar */ | |
b5dc0163 AS |
5042 | err = mark_chain_precision(env, insn->src_reg); |
5043 | if (err) | |
5044 | return err; | |
82abbf8d AS |
5045 | return adjust_ptr_min_max_vals(env, insn, |
5046 | dst_reg, src_reg); | |
f1174f77 EC |
5047 | } |
5048 | } else { | |
5049 | /* Pretend the src is a reg with a known value, since we only | |
5050 | * need to be able to read from this state. | |
5051 | */ | |
5052 | off_reg.type = SCALAR_VALUE; | |
b03c9f9f | 5053 | __mark_reg_known(&off_reg, insn->imm); |
f1174f77 | 5054 | src_reg = &off_reg; |
82abbf8d AS |
5055 | if (ptr_reg) /* pointer += K */ |
5056 | return adjust_ptr_min_max_vals(env, insn, | |
5057 | ptr_reg, src_reg); | |
f1174f77 EC |
5058 | } |
5059 | ||
5060 | /* Got here implies adding two SCALAR_VALUEs */ | |
5061 | if (WARN_ON_ONCE(ptr_reg)) { | |
f4d7e40a | 5062 | print_verifier_state(env, state); |
61bd5218 | 5063 | verbose(env, "verifier internal error: unexpected ptr_reg\n"); |
f1174f77 EC |
5064 | return -EINVAL; |
5065 | } | |
5066 | if (WARN_ON(!src_reg)) { | |
f4d7e40a | 5067 | print_verifier_state(env, state); |
61bd5218 | 5068 | verbose(env, "verifier internal error: no src_reg\n"); |
f1174f77 EC |
5069 | return -EINVAL; |
5070 | } | |
5071 | return adjust_scalar_min_max_vals(env, insn, dst_reg, *src_reg); | |
48461135 JB |
5072 | } |
5073 | ||
17a52670 | 5074 | /* check validity of 32-bit and 64-bit arithmetic operations */ |
58e2af8b | 5075 | static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) |
17a52670 | 5076 | { |
638f5b90 | 5077 | struct bpf_reg_state *regs = cur_regs(env); |
17a52670 AS |
5078 | u8 opcode = BPF_OP(insn->code); |
5079 | int err; | |
5080 | ||
5081 | if (opcode == BPF_END || opcode == BPF_NEG) { | |
5082 | if (opcode == BPF_NEG) { | |
5083 | if (BPF_SRC(insn->code) != 0 || | |
5084 | insn->src_reg != BPF_REG_0 || | |
5085 | insn->off != 0 || insn->imm != 0) { | |
61bd5218 | 5086 | verbose(env, "BPF_NEG uses reserved fields\n"); |
17a52670 AS |
5087 | return -EINVAL; |
5088 | } | |
5089 | } else { | |
5090 | if (insn->src_reg != BPF_REG_0 || insn->off != 0 || | |
e67b8a68 EC |
5091 | (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) || |
5092 | BPF_CLASS(insn->code) == BPF_ALU64) { | |
61bd5218 | 5093 | verbose(env, "BPF_END uses reserved fields\n"); |
17a52670 AS |
5094 | return -EINVAL; |
5095 | } | |
5096 | } | |
5097 | ||
5098 | /* check src operand */ | |
dc503a8a | 5099 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
5100 | if (err) |
5101 | return err; | |
5102 | ||
1be7f75d | 5103 | if (is_pointer_value(env, insn->dst_reg)) { |
61bd5218 | 5104 | verbose(env, "R%d pointer arithmetic prohibited\n", |
1be7f75d AS |
5105 | insn->dst_reg); |
5106 | return -EACCES; | |
5107 | } | |
5108 | ||
17a52670 | 5109 | /* check dest operand */ |
dc503a8a | 5110 | err = check_reg_arg(env, insn->dst_reg, DST_OP); |
17a52670 AS |
5111 | if (err) |
5112 | return err; | |
5113 | ||
5114 | } else if (opcode == BPF_MOV) { | |
5115 | ||
5116 | if (BPF_SRC(insn->code) == BPF_X) { | |
5117 | if (insn->imm != 0 || insn->off != 0) { | |
61bd5218 | 5118 | verbose(env, "BPF_MOV uses reserved fields\n"); |
17a52670 AS |
5119 | return -EINVAL; |
5120 | } | |
5121 | ||
5122 | /* check src operand */ | |
dc503a8a | 5123 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
5124 | if (err) |
5125 | return err; | |
5126 | } else { | |
5127 | if (insn->src_reg != BPF_REG_0 || insn->off != 0) { | |
61bd5218 | 5128 | verbose(env, "BPF_MOV uses reserved fields\n"); |
17a52670 AS |
5129 | return -EINVAL; |
5130 | } | |
5131 | } | |
5132 | ||
fbeb1603 AF |
5133 | /* check dest operand, mark as required later */ |
5134 | err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); | |
17a52670 AS |
5135 | if (err) |
5136 | return err; | |
5137 | ||
5138 | if (BPF_SRC(insn->code) == BPF_X) { | |
e434b8cd JW |
5139 | struct bpf_reg_state *src_reg = regs + insn->src_reg; |
5140 | struct bpf_reg_state *dst_reg = regs + insn->dst_reg; | |
5141 | ||
17a52670 AS |
5142 | if (BPF_CLASS(insn->code) == BPF_ALU64) { |
5143 | /* case: R1 = R2 | |
5144 | * copy register state to dest reg | |
5145 | */ | |
e434b8cd JW |
5146 | *dst_reg = *src_reg; |
5147 | dst_reg->live |= REG_LIVE_WRITTEN; | |
5327ed3d | 5148 | dst_reg->subreg_def = DEF_NOT_SUBREG; |
17a52670 | 5149 | } else { |
f1174f77 | 5150 | /* R1 = (u32) R2 */ |
1be7f75d | 5151 | if (is_pointer_value(env, insn->src_reg)) { |
61bd5218 JK |
5152 | verbose(env, |
5153 | "R%d partial copy of pointer\n", | |
1be7f75d AS |
5154 | insn->src_reg); |
5155 | return -EACCES; | |
e434b8cd JW |
5156 | } else if (src_reg->type == SCALAR_VALUE) { |
5157 | *dst_reg = *src_reg; | |
5158 | dst_reg->live |= REG_LIVE_WRITTEN; | |
5327ed3d | 5159 | dst_reg->subreg_def = env->insn_idx + 1; |
e434b8cd JW |
5160 | } else { |
5161 | mark_reg_unknown(env, regs, | |
5162 | insn->dst_reg); | |
1be7f75d | 5163 | } |
e434b8cd | 5164 | coerce_reg_to_size(dst_reg, 4); |
17a52670 AS |
5165 | } |
5166 | } else { | |
5167 | /* case: R = imm | |
5168 | * remember the value we stored into this reg | |
5169 | */ | |
fbeb1603 AF |
5170 | /* clear any state __mark_reg_known doesn't set */ |
5171 | mark_reg_unknown(env, regs, insn->dst_reg); | |
f1174f77 | 5172 | regs[insn->dst_reg].type = SCALAR_VALUE; |
95a762e2 JH |
5173 | if (BPF_CLASS(insn->code) == BPF_ALU64) { |
5174 | __mark_reg_known(regs + insn->dst_reg, | |
5175 | insn->imm); | |
5176 | } else { | |
5177 | __mark_reg_known(regs + insn->dst_reg, | |
5178 | (u32)insn->imm); | |
5179 | } | |
17a52670 AS |
5180 | } |
5181 | ||
5182 | } else if (opcode > BPF_END) { | |
61bd5218 | 5183 | verbose(env, "invalid BPF_ALU opcode %x\n", opcode); |
17a52670 AS |
5184 | return -EINVAL; |
5185 | ||
5186 | } else { /* all other ALU ops: and, sub, xor, add, ... */ | |
5187 | ||
17a52670 AS |
5188 | if (BPF_SRC(insn->code) == BPF_X) { |
5189 | if (insn->imm != 0 || insn->off != 0) { | |
61bd5218 | 5190 | verbose(env, "BPF_ALU uses reserved fields\n"); |
17a52670 AS |
5191 | return -EINVAL; |
5192 | } | |
5193 | /* check src1 operand */ | |
dc503a8a | 5194 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
5195 | if (err) |
5196 | return err; | |
5197 | } else { | |
5198 | if (insn->src_reg != BPF_REG_0 || insn->off != 0) { | |
61bd5218 | 5199 | verbose(env, "BPF_ALU uses reserved fields\n"); |
17a52670 AS |
5200 | return -EINVAL; |
5201 | } | |
5202 | } | |
5203 | ||
5204 | /* check src2 operand */ | |
dc503a8a | 5205 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
5206 | if (err) |
5207 | return err; | |
5208 | ||
5209 | if ((opcode == BPF_MOD || opcode == BPF_DIV) && | |
5210 | BPF_SRC(insn->code) == BPF_K && insn->imm == 0) { | |
61bd5218 | 5211 | verbose(env, "div by zero\n"); |
17a52670 AS |
5212 | return -EINVAL; |
5213 | } | |
5214 | ||
229394e8 RV |
5215 | if ((opcode == BPF_LSH || opcode == BPF_RSH || |
5216 | opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) { | |
5217 | int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32; | |
5218 | ||
5219 | if (insn->imm < 0 || insn->imm >= size) { | |
61bd5218 | 5220 | verbose(env, "invalid shift %d\n", insn->imm); |
229394e8 RV |
5221 | return -EINVAL; |
5222 | } | |
5223 | } | |
5224 | ||
1a0dc1ac | 5225 | /* check dest operand */ |
dc503a8a | 5226 | err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); |
1a0dc1ac AS |
5227 | if (err) |
5228 | return err; | |
5229 | ||
f1174f77 | 5230 | return adjust_reg_min_max_vals(env, insn); |
17a52670 AS |
5231 | } |
5232 | ||
5233 | return 0; | |
5234 | } | |
5235 | ||
c6a9efa1 PC |
5236 | static void __find_good_pkt_pointers(struct bpf_func_state *state, |
5237 | struct bpf_reg_state *dst_reg, | |
5238 | enum bpf_reg_type type, u16 new_range) | |
5239 | { | |
5240 | struct bpf_reg_state *reg; | |
5241 | int i; | |
5242 | ||
5243 | for (i = 0; i < MAX_BPF_REG; i++) { | |
5244 | reg = &state->regs[i]; | |
5245 | if (reg->type == type && reg->id == dst_reg->id) | |
5246 | /* keep the maximum range already checked */ | |
5247 | reg->range = max(reg->range, new_range); | |
5248 | } | |
5249 | ||
5250 | bpf_for_each_spilled_reg(i, state, reg) { | |
5251 | if (!reg) | |
5252 | continue; | |
5253 | if (reg->type == type && reg->id == dst_reg->id) | |
5254 | reg->range = max(reg->range, new_range); | |
5255 | } | |
5256 | } | |
5257 | ||
f4d7e40a | 5258 | static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, |
de8f3a83 | 5259 | struct bpf_reg_state *dst_reg, |
f8ddadc4 | 5260 | enum bpf_reg_type type, |
fb2a311a | 5261 | bool range_right_open) |
969bf05e | 5262 | { |
fb2a311a | 5263 | u16 new_range; |
c6a9efa1 | 5264 | int i; |
2d2be8ca | 5265 | |
fb2a311a DB |
5266 | if (dst_reg->off < 0 || |
5267 | (dst_reg->off == 0 && range_right_open)) | |
f1174f77 EC |
5268 | /* This doesn't give us any range */ |
5269 | return; | |
5270 | ||
b03c9f9f EC |
5271 | if (dst_reg->umax_value > MAX_PACKET_OFF || |
5272 | dst_reg->umax_value + dst_reg->off > MAX_PACKET_OFF) | |
f1174f77 EC |
5273 | /* Risk of overflow. For instance, ptr + (1<<63) may be less |
5274 | * than pkt_end, but that's because it's also less than pkt. | |
5275 | */ | |
5276 | return; | |
5277 | ||
fb2a311a DB |
5278 | new_range = dst_reg->off; |
5279 | if (range_right_open) | |
5280 | new_range--; | |
5281 | ||
5282 | /* Examples for register markings: | |
2d2be8ca | 5283 | * |
fb2a311a | 5284 | * pkt_data in dst register: |
2d2be8ca DB |
5285 | * |
5286 | * r2 = r3; | |
5287 | * r2 += 8; | |
5288 | * if (r2 > pkt_end) goto <handle exception> | |
5289 | * <access okay> | |
5290 | * | |
b4e432f1 DB |
5291 | * r2 = r3; |
5292 | * r2 += 8; | |
5293 | * if (r2 < pkt_end) goto <access okay> | |
5294 | * <handle exception> | |
5295 | * | |
2d2be8ca DB |
5296 | * Where: |
5297 | * r2 == dst_reg, pkt_end == src_reg | |
5298 | * r2=pkt(id=n,off=8,r=0) | |
5299 | * r3=pkt(id=n,off=0,r=0) | |
5300 | * | |
fb2a311a | 5301 | * pkt_data in src register: |
2d2be8ca DB |
5302 | * |
5303 | * r2 = r3; | |
5304 | * r2 += 8; | |
5305 | * if (pkt_end >= r2) goto <access okay> | |
5306 | * <handle exception> | |
5307 | * | |
b4e432f1 DB |
5308 | * r2 = r3; |
5309 | * r2 += 8; | |
5310 | * if (pkt_end <= r2) goto <handle exception> | |
5311 | * <access okay> | |
5312 | * | |
2d2be8ca DB |
5313 | * Where: |
5314 | * pkt_end == dst_reg, r2 == src_reg | |
5315 | * r2=pkt(id=n,off=8,r=0) | |
5316 | * r3=pkt(id=n,off=0,r=0) | |
5317 | * | |
5318 | * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8) | |
fb2a311a DB |
5319 | * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8) |
5320 | * and [r3, r3 + 8-1) respectively is safe to access depending on | |
5321 | * the check. | |
969bf05e | 5322 | */ |
2d2be8ca | 5323 | |
f1174f77 EC |
5324 | /* If our ids match, then we must have the same max_value. And we |
5325 | * don't care about the other reg's fixed offset, since if it's too big | |
5326 | * the range won't allow anything. | |
5327 | * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16. | |
5328 | */ | |
c6a9efa1 PC |
5329 | for (i = 0; i <= vstate->curframe; i++) |
5330 | __find_good_pkt_pointers(vstate->frame[i], dst_reg, type, | |
5331 | new_range); | |
969bf05e AS |
5332 | } |
5333 | ||
4f7b3e82 AS |
5334 | /* compute branch direction of the expression "if (reg opcode val) goto target;" |
5335 | * and return: | |
5336 | * 1 - branch will be taken and "goto target" will be executed | |
5337 | * 0 - branch will not be taken and fall-through to next insn | |
5338 | * -1 - unknown. Example: "if (reg < 5)" is unknown when register value range [0,10] | |
5339 | */ | |
092ed096 JW |
5340 | static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode, |
5341 | bool is_jmp32) | |
4f7b3e82 | 5342 | { |
092ed096 | 5343 | struct bpf_reg_state reg_lo; |
a72dafaf JW |
5344 | s64 sval; |
5345 | ||
4f7b3e82 AS |
5346 | if (__is_pointer_value(false, reg)) |
5347 | return -1; | |
5348 | ||
092ed096 JW |
5349 | if (is_jmp32) { |
5350 | reg_lo = *reg; | |
5351 | reg = ®_lo; | |
5352 | /* For JMP32, only low 32 bits are compared, coerce_reg_to_size | |
5353 | * could truncate high bits and update umin/umax according to | |
5354 | * information of low bits. | |
5355 | */ | |
5356 | coerce_reg_to_size(reg, 4); | |
5357 | /* smin/smax need special handling. For example, after coerce, | |
5358 | * if smin_value is 0x00000000ffffffffLL, the value is -1 when | |
5359 | * used as operand to JMP32. It is a negative number from s32's | |
5360 | * point of view, while it is a positive number when seen as | |
5361 | * s64. The smin/smax are kept as s64, therefore, when used with | |
5362 | * JMP32, they need to be transformed into s32, then sign | |
5363 | * extended back to s64. | |
5364 | * | |
5365 | * Also, smin/smax were copied from umin/umax. If umin/umax has | |
5366 | * different sign bit, then min/max relationship doesn't | |
5367 | * maintain after casting into s32, for this case, set smin/smax | |
5368 | * to safest range. | |
5369 | */ | |
5370 | if ((reg->umax_value ^ reg->umin_value) & | |
5371 | (1ULL << 31)) { | |
5372 | reg->smin_value = S32_MIN; | |
5373 | reg->smax_value = S32_MAX; | |
5374 | } | |
5375 | reg->smin_value = (s64)(s32)reg->smin_value; | |
5376 | reg->smax_value = (s64)(s32)reg->smax_value; | |
5377 | ||
5378 | val = (u32)val; | |
5379 | sval = (s64)(s32)val; | |
5380 | } else { | |
5381 | sval = (s64)val; | |
5382 | } | |
a72dafaf | 5383 | |
4f7b3e82 AS |
5384 | switch (opcode) { |
5385 | case BPF_JEQ: | |
5386 | if (tnum_is_const(reg->var_off)) | |
5387 | return !!tnum_equals_const(reg->var_off, val); | |
5388 | break; | |
5389 | case BPF_JNE: | |
5390 | if (tnum_is_const(reg->var_off)) | |
5391 | return !tnum_equals_const(reg->var_off, val); | |
5392 | break; | |
960ea056 JK |
5393 | case BPF_JSET: |
5394 | if ((~reg->var_off.mask & reg->var_off.value) & val) | |
5395 | return 1; | |
5396 | if (!((reg->var_off.mask | reg->var_off.value) & val)) | |
5397 | return 0; | |
5398 | break; | |
4f7b3e82 AS |
5399 | case BPF_JGT: |
5400 | if (reg->umin_value > val) | |
5401 | return 1; | |
5402 | else if (reg->umax_value <= val) | |
5403 | return 0; | |
5404 | break; | |
5405 | case BPF_JSGT: | |
a72dafaf | 5406 | if (reg->smin_value > sval) |
4f7b3e82 | 5407 | return 1; |
a72dafaf | 5408 | else if (reg->smax_value < sval) |
4f7b3e82 AS |
5409 | return 0; |
5410 | break; | |
5411 | case BPF_JLT: | |
5412 | if (reg->umax_value < val) | |
5413 | return 1; | |
5414 | else if (reg->umin_value >= val) | |
5415 | return 0; | |
5416 | break; | |
5417 | case BPF_JSLT: | |
a72dafaf | 5418 | if (reg->smax_value < sval) |
4f7b3e82 | 5419 | return 1; |
a72dafaf | 5420 | else if (reg->smin_value >= sval) |
4f7b3e82 AS |
5421 | return 0; |
5422 | break; | |
5423 | case BPF_JGE: | |
5424 | if (reg->umin_value >= val) | |
5425 | return 1; | |
5426 | else if (reg->umax_value < val) | |
5427 | return 0; | |
5428 | break; | |
5429 | case BPF_JSGE: | |
a72dafaf | 5430 | if (reg->smin_value >= sval) |
4f7b3e82 | 5431 | return 1; |
a72dafaf | 5432 | else if (reg->smax_value < sval) |
4f7b3e82 AS |
5433 | return 0; |
5434 | break; | |
5435 | case BPF_JLE: | |
5436 | if (reg->umax_value <= val) | |
5437 | return 1; | |
5438 | else if (reg->umin_value > val) | |
5439 | return 0; | |
5440 | break; | |
5441 | case BPF_JSLE: | |
a72dafaf | 5442 | if (reg->smax_value <= sval) |
4f7b3e82 | 5443 | return 1; |
a72dafaf | 5444 | else if (reg->smin_value > sval) |
4f7b3e82 AS |
5445 | return 0; |
5446 | break; | |
5447 | } | |
5448 | ||
5449 | return -1; | |
5450 | } | |
5451 | ||
092ed096 JW |
5452 | /* Generate min value of the high 32-bit from TNUM info. */ |
5453 | static u64 gen_hi_min(struct tnum var) | |
5454 | { | |
5455 | return var.value & ~0xffffffffULL; | |
5456 | } | |
5457 | ||
5458 | /* Generate max value of the high 32-bit from TNUM info. */ | |
5459 | static u64 gen_hi_max(struct tnum var) | |
5460 | { | |
5461 | return (var.value | var.mask) & ~0xffffffffULL; | |
5462 | } | |
5463 | ||
5464 | /* Return true if VAL is compared with a s64 sign extended from s32, and they | |
5465 | * are with the same signedness. | |
5466 | */ | |
5467 | static bool cmp_val_with_extended_s64(s64 sval, struct bpf_reg_state *reg) | |
5468 | { | |
5469 | return ((s32)sval >= 0 && | |
5470 | reg->smin_value >= 0 && reg->smax_value <= S32_MAX) || | |
5471 | ((s32)sval < 0 && | |
5472 | reg->smax_value <= 0 && reg->smin_value >= S32_MIN); | |
5473 | } | |
5474 | ||
48461135 JB |
5475 | /* Adjusts the register min/max values in the case that the dst_reg is the |
5476 | * variable register that we are working on, and src_reg is a constant or we're | |
5477 | * simply doing a BPF_K check. | |
f1174f77 | 5478 | * In JEQ/JNE cases we also adjust the var_off values. |
48461135 JB |
5479 | */ |
5480 | static void reg_set_min_max(struct bpf_reg_state *true_reg, | |
5481 | struct bpf_reg_state *false_reg, u64 val, | |
092ed096 | 5482 | u8 opcode, bool is_jmp32) |
48461135 | 5483 | { |
a72dafaf JW |
5484 | s64 sval; |
5485 | ||
f1174f77 EC |
5486 | /* If the dst_reg is a pointer, we can't learn anything about its |
5487 | * variable offset from the compare (unless src_reg were a pointer into | |
5488 | * the same object, but we don't bother with that. | |
5489 | * Since false_reg and true_reg have the same type by construction, we | |
5490 | * only need to check one of them for pointerness. | |
5491 | */ | |
5492 | if (__is_pointer_value(false, false_reg)) | |
5493 | return; | |
4cabc5b1 | 5494 | |
092ed096 JW |
5495 | val = is_jmp32 ? (u32)val : val; |
5496 | sval = is_jmp32 ? (s64)(s32)val : (s64)val; | |
a72dafaf | 5497 | |
48461135 JB |
5498 | switch (opcode) { |
5499 | case BPF_JEQ: | |
48461135 | 5500 | case BPF_JNE: |
a72dafaf JW |
5501 | { |
5502 | struct bpf_reg_state *reg = | |
5503 | opcode == BPF_JEQ ? true_reg : false_reg; | |
5504 | ||
5505 | /* For BPF_JEQ, if this is false we know nothing Jon Snow, but | |
5506 | * if it is true we know the value for sure. Likewise for | |
5507 | * BPF_JNE. | |
48461135 | 5508 | */ |
092ed096 JW |
5509 | if (is_jmp32) { |
5510 | u64 old_v = reg->var_off.value; | |
5511 | u64 hi_mask = ~0xffffffffULL; | |
5512 | ||
5513 | reg->var_off.value = (old_v & hi_mask) | val; | |
5514 | reg->var_off.mask &= hi_mask; | |
5515 | } else { | |
5516 | __mark_reg_known(reg, val); | |
5517 | } | |
48461135 | 5518 | break; |
a72dafaf | 5519 | } |
960ea056 JK |
5520 | case BPF_JSET: |
5521 | false_reg->var_off = tnum_and(false_reg->var_off, | |
5522 | tnum_const(~val)); | |
5523 | if (is_power_of_2(val)) | |
5524 | true_reg->var_off = tnum_or(true_reg->var_off, | |
5525 | tnum_const(val)); | |
5526 | break; | |
48461135 | 5527 | case BPF_JGE: |
a72dafaf JW |
5528 | case BPF_JGT: |
5529 | { | |
5530 | u64 false_umax = opcode == BPF_JGT ? val : val - 1; | |
5531 | u64 true_umin = opcode == BPF_JGT ? val + 1 : val; | |
5532 | ||
092ed096 JW |
5533 | if (is_jmp32) { |
5534 | false_umax += gen_hi_max(false_reg->var_off); | |
5535 | true_umin += gen_hi_min(true_reg->var_off); | |
5536 | } | |
a72dafaf JW |
5537 | false_reg->umax_value = min(false_reg->umax_value, false_umax); |
5538 | true_reg->umin_value = max(true_reg->umin_value, true_umin); | |
b03c9f9f | 5539 | break; |
a72dafaf | 5540 | } |
48461135 | 5541 | case BPF_JSGE: |
a72dafaf JW |
5542 | case BPF_JSGT: |
5543 | { | |
5544 | s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1; | |
5545 | s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval; | |
5546 | ||
092ed096 JW |
5547 | /* If the full s64 was not sign-extended from s32 then don't |
5548 | * deduct further info. | |
5549 | */ | |
5550 | if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) | |
5551 | break; | |
a72dafaf JW |
5552 | false_reg->smax_value = min(false_reg->smax_value, false_smax); |
5553 | true_reg->smin_value = max(true_reg->smin_value, true_smin); | |
48461135 | 5554 | break; |
a72dafaf | 5555 | } |
b4e432f1 | 5556 | case BPF_JLE: |
a72dafaf JW |
5557 | case BPF_JLT: |
5558 | { | |
5559 | u64 false_umin = opcode == BPF_JLT ? val : val + 1; | |
5560 | u64 true_umax = opcode == BPF_JLT ? val - 1 : val; | |
5561 | ||
092ed096 JW |
5562 | if (is_jmp32) { |
5563 | false_umin += gen_hi_min(false_reg->var_off); | |
5564 | true_umax += gen_hi_max(true_reg->var_off); | |
5565 | } | |
a72dafaf JW |
5566 | false_reg->umin_value = max(false_reg->umin_value, false_umin); |
5567 | true_reg->umax_value = min(true_reg->umax_value, true_umax); | |
b4e432f1 | 5568 | break; |
a72dafaf | 5569 | } |
b4e432f1 | 5570 | case BPF_JSLE: |
a72dafaf JW |
5571 | case BPF_JSLT: |
5572 | { | |
5573 | s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1; | |
5574 | s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval; | |
5575 | ||
092ed096 JW |
5576 | if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) |
5577 | break; | |
a72dafaf JW |
5578 | false_reg->smin_value = max(false_reg->smin_value, false_smin); |
5579 | true_reg->smax_value = min(true_reg->smax_value, true_smax); | |
b4e432f1 | 5580 | break; |
a72dafaf | 5581 | } |
48461135 JB |
5582 | default: |
5583 | break; | |
5584 | } | |
5585 | ||
b03c9f9f EC |
5586 | __reg_deduce_bounds(false_reg); |
5587 | __reg_deduce_bounds(true_reg); | |
5588 | /* We might have learned some bits from the bounds. */ | |
5589 | __reg_bound_offset(false_reg); | |
5590 | __reg_bound_offset(true_reg); | |
5591 | /* Intersecting with the old var_off might have improved our bounds | |
5592 | * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), | |
5593 | * then new var_off is (0; 0x7f...fc) which improves our umax. | |
5594 | */ | |
5595 | __update_reg_bounds(false_reg); | |
5596 | __update_reg_bounds(true_reg); | |
48461135 JB |
5597 | } |
5598 | ||
f1174f77 EC |
5599 | /* Same as above, but for the case that dst_reg holds a constant and src_reg is |
5600 | * the variable reg. | |
48461135 JB |
5601 | */ |
5602 | static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, | |
5603 | struct bpf_reg_state *false_reg, u64 val, | |
092ed096 | 5604 | u8 opcode, bool is_jmp32) |
48461135 | 5605 | { |
a72dafaf JW |
5606 | s64 sval; |
5607 | ||
f1174f77 EC |
5608 | if (__is_pointer_value(false, false_reg)) |
5609 | return; | |
4cabc5b1 | 5610 | |
092ed096 JW |
5611 | val = is_jmp32 ? (u32)val : val; |
5612 | sval = is_jmp32 ? (s64)(s32)val : (s64)val; | |
a72dafaf | 5613 | |
48461135 JB |
5614 | switch (opcode) { |
5615 | case BPF_JEQ: | |
48461135 | 5616 | case BPF_JNE: |
a72dafaf JW |
5617 | { |
5618 | struct bpf_reg_state *reg = | |
5619 | opcode == BPF_JEQ ? true_reg : false_reg; | |
5620 | ||
092ed096 JW |
5621 | if (is_jmp32) { |
5622 | u64 old_v = reg->var_off.value; | |
5623 | u64 hi_mask = ~0xffffffffULL; | |
5624 | ||
5625 | reg->var_off.value = (old_v & hi_mask) | val; | |
5626 | reg->var_off.mask &= hi_mask; | |
5627 | } else { | |
5628 | __mark_reg_known(reg, val); | |
5629 | } | |
48461135 | 5630 | break; |
a72dafaf | 5631 | } |
960ea056 JK |
5632 | case BPF_JSET: |
5633 | false_reg->var_off = tnum_and(false_reg->var_off, | |
5634 | tnum_const(~val)); | |
5635 | if (is_power_of_2(val)) | |
5636 | true_reg->var_off = tnum_or(true_reg->var_off, | |
5637 | tnum_const(val)); | |
5638 | break; | |
48461135 | 5639 | case BPF_JGE: |
a72dafaf JW |
5640 | case BPF_JGT: |
5641 | { | |
5642 | u64 false_umin = opcode == BPF_JGT ? val : val + 1; | |
5643 | u64 true_umax = opcode == BPF_JGT ? val - 1 : val; | |
5644 | ||
092ed096 JW |
5645 | if (is_jmp32) { |
5646 | false_umin += gen_hi_min(false_reg->var_off); | |
5647 | true_umax += gen_hi_max(true_reg->var_off); | |
5648 | } | |
a72dafaf JW |
5649 | false_reg->umin_value = max(false_reg->umin_value, false_umin); |
5650 | true_reg->umax_value = min(true_reg->umax_value, true_umax); | |
b03c9f9f | 5651 | break; |
a72dafaf | 5652 | } |
48461135 | 5653 | case BPF_JSGE: |
a72dafaf JW |
5654 | case BPF_JSGT: |
5655 | { | |
5656 | s64 false_smin = opcode == BPF_JSGT ? sval : sval + 1; | |
5657 | s64 true_smax = opcode == BPF_JSGT ? sval - 1 : sval; | |
5658 | ||
092ed096 JW |
5659 | if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) |
5660 | break; | |
a72dafaf JW |
5661 | false_reg->smin_value = max(false_reg->smin_value, false_smin); |
5662 | true_reg->smax_value = min(true_reg->smax_value, true_smax); | |
48461135 | 5663 | break; |
a72dafaf | 5664 | } |
b4e432f1 | 5665 | case BPF_JLE: |
a72dafaf JW |
5666 | case BPF_JLT: |
5667 | { | |
5668 | u64 false_umax = opcode == BPF_JLT ? val : val - 1; | |
5669 | u64 true_umin = opcode == BPF_JLT ? val + 1 : val; | |
5670 | ||
092ed096 JW |
5671 | if (is_jmp32) { |
5672 | false_umax += gen_hi_max(false_reg->var_off); | |
5673 | true_umin += gen_hi_min(true_reg->var_off); | |
5674 | } | |
a72dafaf JW |
5675 | false_reg->umax_value = min(false_reg->umax_value, false_umax); |
5676 | true_reg->umin_value = max(true_reg->umin_value, true_umin); | |
b4e432f1 | 5677 | break; |
a72dafaf | 5678 | } |
b4e432f1 | 5679 | case BPF_JSLE: |
a72dafaf JW |
5680 | case BPF_JSLT: |
5681 | { | |
5682 | s64 false_smax = opcode == BPF_JSLT ? sval : sval - 1; | |
5683 | s64 true_smin = opcode == BPF_JSLT ? sval + 1 : sval; | |
5684 | ||
092ed096 JW |
5685 | if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) |
5686 | break; | |
a72dafaf JW |
5687 | false_reg->smax_value = min(false_reg->smax_value, false_smax); |
5688 | true_reg->smin_value = max(true_reg->smin_value, true_smin); | |
b4e432f1 | 5689 | break; |
a72dafaf | 5690 | } |
48461135 JB |
5691 | default: |
5692 | break; | |
5693 | } | |
5694 | ||
b03c9f9f EC |
5695 | __reg_deduce_bounds(false_reg); |
5696 | __reg_deduce_bounds(true_reg); | |
5697 | /* We might have learned some bits from the bounds. */ | |
5698 | __reg_bound_offset(false_reg); | |
5699 | __reg_bound_offset(true_reg); | |
5700 | /* Intersecting with the old var_off might have improved our bounds | |
5701 | * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), | |
5702 | * then new var_off is (0; 0x7f...fc) which improves our umax. | |
5703 | */ | |
5704 | __update_reg_bounds(false_reg); | |
5705 | __update_reg_bounds(true_reg); | |
f1174f77 EC |
5706 | } |
5707 | ||
5708 | /* Regs are known to be equal, so intersect their min/max/var_off */ | |
5709 | static void __reg_combine_min_max(struct bpf_reg_state *src_reg, | |
5710 | struct bpf_reg_state *dst_reg) | |
5711 | { | |
b03c9f9f EC |
5712 | src_reg->umin_value = dst_reg->umin_value = max(src_reg->umin_value, |
5713 | dst_reg->umin_value); | |
5714 | src_reg->umax_value = dst_reg->umax_value = min(src_reg->umax_value, | |
5715 | dst_reg->umax_value); | |
5716 | src_reg->smin_value = dst_reg->smin_value = max(src_reg->smin_value, | |
5717 | dst_reg->smin_value); | |
5718 | src_reg->smax_value = dst_reg->smax_value = min(src_reg->smax_value, | |
5719 | dst_reg->smax_value); | |
f1174f77 EC |
5720 | src_reg->var_off = dst_reg->var_off = tnum_intersect(src_reg->var_off, |
5721 | dst_reg->var_off); | |
b03c9f9f EC |
5722 | /* We might have learned new bounds from the var_off. */ |
5723 | __update_reg_bounds(src_reg); | |
5724 | __update_reg_bounds(dst_reg); | |
5725 | /* We might have learned something about the sign bit. */ | |
5726 | __reg_deduce_bounds(src_reg); | |
5727 | __reg_deduce_bounds(dst_reg); | |
5728 | /* We might have learned some bits from the bounds. */ | |
5729 | __reg_bound_offset(src_reg); | |
5730 | __reg_bound_offset(dst_reg); | |
5731 | /* Intersecting with the old var_off might have improved our bounds | |
5732 | * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), | |
5733 | * then new var_off is (0; 0x7f...fc) which improves our umax. | |
5734 | */ | |
5735 | __update_reg_bounds(src_reg); | |
5736 | __update_reg_bounds(dst_reg); | |
f1174f77 EC |
5737 | } |
5738 | ||
5739 | static void reg_combine_min_max(struct bpf_reg_state *true_src, | |
5740 | struct bpf_reg_state *true_dst, | |
5741 | struct bpf_reg_state *false_src, | |
5742 | struct bpf_reg_state *false_dst, | |
5743 | u8 opcode) | |
5744 | { | |
5745 | switch (opcode) { | |
5746 | case BPF_JEQ: | |
5747 | __reg_combine_min_max(true_src, true_dst); | |
5748 | break; | |
5749 | case BPF_JNE: | |
5750 | __reg_combine_min_max(false_src, false_dst); | |
b03c9f9f | 5751 | break; |
4cabc5b1 | 5752 | } |
48461135 JB |
5753 | } |
5754 | ||
fd978bf7 JS |
5755 | static void mark_ptr_or_null_reg(struct bpf_func_state *state, |
5756 | struct bpf_reg_state *reg, u32 id, | |
840b9615 | 5757 | bool is_null) |
57a09bf0 | 5758 | { |
840b9615 | 5759 | if (reg_type_may_be_null(reg->type) && reg->id == id) { |
f1174f77 EC |
5760 | /* Old offset (both fixed and variable parts) should |
5761 | * have been known-zero, because we don't allow pointer | |
5762 | * arithmetic on pointers that might be NULL. | |
5763 | */ | |
b03c9f9f EC |
5764 | if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || |
5765 | !tnum_equals_const(reg->var_off, 0) || | |
f1174f77 | 5766 | reg->off)) { |
b03c9f9f EC |
5767 | __mark_reg_known_zero(reg); |
5768 | reg->off = 0; | |
f1174f77 EC |
5769 | } |
5770 | if (is_null) { | |
5771 | reg->type = SCALAR_VALUE; | |
840b9615 JS |
5772 | } else if (reg->type == PTR_TO_MAP_VALUE_OR_NULL) { |
5773 | if (reg->map_ptr->inner_map_meta) { | |
5774 | reg->type = CONST_PTR_TO_MAP; | |
5775 | reg->map_ptr = reg->map_ptr->inner_map_meta; | |
fada7fdc JL |
5776 | } else if (reg->map_ptr->map_type == |
5777 | BPF_MAP_TYPE_XSKMAP) { | |
5778 | reg->type = PTR_TO_XDP_SOCK; | |
840b9615 JS |
5779 | } else { |
5780 | reg->type = PTR_TO_MAP_VALUE; | |
5781 | } | |
c64b7983 JS |
5782 | } else if (reg->type == PTR_TO_SOCKET_OR_NULL) { |
5783 | reg->type = PTR_TO_SOCKET; | |
46f8bc92 MKL |
5784 | } else if (reg->type == PTR_TO_SOCK_COMMON_OR_NULL) { |
5785 | reg->type = PTR_TO_SOCK_COMMON; | |
655a51e5 MKL |
5786 | } else if (reg->type == PTR_TO_TCP_SOCK_OR_NULL) { |
5787 | reg->type = PTR_TO_TCP_SOCK; | |
56f668df | 5788 | } |
1b986589 MKL |
5789 | if (is_null) { |
5790 | /* We don't need id and ref_obj_id from this point | |
5791 | * onwards anymore, thus we should better reset it, | |
5792 | * so that state pruning has chances to take effect. | |
5793 | */ | |
5794 | reg->id = 0; | |
5795 | reg->ref_obj_id = 0; | |
5796 | } else if (!reg_may_point_to_spin_lock(reg)) { | |
5797 | /* For not-NULL ptr, reg->ref_obj_id will be reset | |
5798 | * in release_reg_references(). | |
5799 | * | |
5800 | * reg->id is still used by spin_lock ptr. Other | |
5801 | * than spin_lock ptr type, reg->id can be reset. | |
fd978bf7 JS |
5802 | */ |
5803 | reg->id = 0; | |
56f668df | 5804 | } |
57a09bf0 TG |
5805 | } |
5806 | } | |
5807 | ||
c6a9efa1 PC |
5808 | static void __mark_ptr_or_null_regs(struct bpf_func_state *state, u32 id, |
5809 | bool is_null) | |
5810 | { | |
5811 | struct bpf_reg_state *reg; | |
5812 | int i; | |
5813 | ||
5814 | for (i = 0; i < MAX_BPF_REG; i++) | |
5815 | mark_ptr_or_null_reg(state, &state->regs[i], id, is_null); | |
5816 | ||
5817 | bpf_for_each_spilled_reg(i, state, reg) { | |
5818 | if (!reg) | |
5819 | continue; | |
5820 | mark_ptr_or_null_reg(state, reg, id, is_null); | |
5821 | } | |
5822 | } | |
5823 | ||
57a09bf0 TG |
5824 | /* The logic is similar to find_good_pkt_pointers(), both could eventually |
5825 | * be folded together at some point. | |
5826 | */ | |
840b9615 JS |
5827 | static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno, |
5828 | bool is_null) | |
57a09bf0 | 5829 | { |
f4d7e40a | 5830 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; |
c6a9efa1 | 5831 | struct bpf_reg_state *regs = state->regs; |
1b986589 | 5832 | u32 ref_obj_id = regs[regno].ref_obj_id; |
a08dd0da | 5833 | u32 id = regs[regno].id; |
c6a9efa1 | 5834 | int i; |
57a09bf0 | 5835 | |
1b986589 MKL |
5836 | if (ref_obj_id && ref_obj_id == id && is_null) |
5837 | /* regs[regno] is in the " == NULL" branch. | |
5838 | * No one could have freed the reference state before | |
5839 | * doing the NULL check. | |
5840 | */ | |
5841 | WARN_ON_ONCE(release_reference_state(state, id)); | |
fd978bf7 | 5842 | |
c6a9efa1 PC |
5843 | for (i = 0; i <= vstate->curframe; i++) |
5844 | __mark_ptr_or_null_regs(vstate->frame[i], id, is_null); | |
57a09bf0 TG |
5845 | } |
5846 | ||
5beca081 DB |
5847 | static bool try_match_pkt_pointers(const struct bpf_insn *insn, |
5848 | struct bpf_reg_state *dst_reg, | |
5849 | struct bpf_reg_state *src_reg, | |
5850 | struct bpf_verifier_state *this_branch, | |
5851 | struct bpf_verifier_state *other_branch) | |
5852 | { | |
5853 | if (BPF_SRC(insn->code) != BPF_X) | |
5854 | return false; | |
5855 | ||
092ed096 JW |
5856 | /* Pointers are always 64-bit. */ |
5857 | if (BPF_CLASS(insn->code) == BPF_JMP32) | |
5858 | return false; | |
5859 | ||
5beca081 DB |
5860 | switch (BPF_OP(insn->code)) { |
5861 | case BPF_JGT: | |
5862 | if ((dst_reg->type == PTR_TO_PACKET && | |
5863 | src_reg->type == PTR_TO_PACKET_END) || | |
5864 | (dst_reg->type == PTR_TO_PACKET_META && | |
5865 | reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) { | |
5866 | /* pkt_data' > pkt_end, pkt_meta' > pkt_data */ | |
5867 | find_good_pkt_pointers(this_branch, dst_reg, | |
5868 | dst_reg->type, false); | |
5869 | } else if ((dst_reg->type == PTR_TO_PACKET_END && | |
5870 | src_reg->type == PTR_TO_PACKET) || | |
5871 | (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && | |
5872 | src_reg->type == PTR_TO_PACKET_META)) { | |
5873 | /* pkt_end > pkt_data', pkt_data > pkt_meta' */ | |
5874 | find_good_pkt_pointers(other_branch, src_reg, | |
5875 | src_reg->type, true); | |
5876 | } else { | |
5877 | return false; | |
5878 | } | |
5879 | break; | |
5880 | case BPF_JLT: | |
5881 | if ((dst_reg->type == PTR_TO_PACKET && | |
5882 | src_reg->type == PTR_TO_PACKET_END) || | |
5883 | (dst_reg->type == PTR_TO_PACKET_META && | |
5884 | reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) { | |
5885 | /* pkt_data' < pkt_end, pkt_meta' < pkt_data */ | |
5886 | find_good_pkt_pointers(other_branch, dst_reg, | |
5887 | dst_reg->type, true); | |
5888 | } else if ((dst_reg->type == PTR_TO_PACKET_END && | |
5889 | src_reg->type == PTR_TO_PACKET) || | |
5890 | (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && | |
5891 | src_reg->type == PTR_TO_PACKET_META)) { | |
5892 | /* pkt_end < pkt_data', pkt_data > pkt_meta' */ | |
5893 | find_good_pkt_pointers(this_branch, src_reg, | |
5894 | src_reg->type, false); | |
5895 | } else { | |
5896 | return false; | |
5897 | } | |
5898 | break; | |
5899 | case BPF_JGE: | |
5900 | if ((dst_reg->type == PTR_TO_PACKET && | |
5901 | src_reg->type == PTR_TO_PACKET_END) || | |
5902 | (dst_reg->type == PTR_TO_PACKET_META && | |
5903 | reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) { | |
5904 | /* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */ | |
5905 | find_good_pkt_pointers(this_branch, dst_reg, | |
5906 | dst_reg->type, true); | |
5907 | } else if ((dst_reg->type == PTR_TO_PACKET_END && | |
5908 | src_reg->type == PTR_TO_PACKET) || | |
5909 | (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && | |
5910 | src_reg->type == PTR_TO_PACKET_META)) { | |
5911 | /* pkt_end >= pkt_data', pkt_data >= pkt_meta' */ | |
5912 | find_good_pkt_pointers(other_branch, src_reg, | |
5913 | src_reg->type, false); | |
5914 | } else { | |
5915 | return false; | |
5916 | } | |
5917 | break; | |
5918 | case BPF_JLE: | |
5919 | if ((dst_reg->type == PTR_TO_PACKET && | |
5920 | src_reg->type == PTR_TO_PACKET_END) || | |
5921 | (dst_reg->type == PTR_TO_PACKET_META && | |
5922 | reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) { | |
5923 | /* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */ | |
5924 | find_good_pkt_pointers(other_branch, dst_reg, | |
5925 | dst_reg->type, false); | |
5926 | } else if ((dst_reg->type == PTR_TO_PACKET_END && | |
5927 | src_reg->type == PTR_TO_PACKET) || | |
5928 | (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && | |
5929 | src_reg->type == PTR_TO_PACKET_META)) { | |
5930 | /* pkt_end <= pkt_data', pkt_data <= pkt_meta' */ | |
5931 | find_good_pkt_pointers(this_branch, src_reg, | |
5932 | src_reg->type, true); | |
5933 | } else { | |
5934 | return false; | |
5935 | } | |
5936 | break; | |
5937 | default: | |
5938 | return false; | |
5939 | } | |
5940 | ||
5941 | return true; | |
5942 | } | |
5943 | ||
58e2af8b | 5944 | static int check_cond_jmp_op(struct bpf_verifier_env *env, |
17a52670 AS |
5945 | struct bpf_insn *insn, int *insn_idx) |
5946 | { | |
f4d7e40a AS |
5947 | struct bpf_verifier_state *this_branch = env->cur_state; |
5948 | struct bpf_verifier_state *other_branch; | |
5949 | struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs; | |
fb8d251e | 5950 | struct bpf_reg_state *dst_reg, *other_branch_regs, *src_reg = NULL; |
17a52670 | 5951 | u8 opcode = BPF_OP(insn->code); |
092ed096 | 5952 | bool is_jmp32; |
fb8d251e | 5953 | int pred = -1; |
17a52670 AS |
5954 | int err; |
5955 | ||
092ed096 JW |
5956 | /* Only conditional jumps are expected to reach here. */ |
5957 | if (opcode == BPF_JA || opcode > BPF_JSLE) { | |
5958 | verbose(env, "invalid BPF_JMP/JMP32 opcode %x\n", opcode); | |
17a52670 AS |
5959 | return -EINVAL; |
5960 | } | |
5961 | ||
5962 | if (BPF_SRC(insn->code) == BPF_X) { | |
5963 | if (insn->imm != 0) { | |
092ed096 | 5964 | verbose(env, "BPF_JMP/JMP32 uses reserved fields\n"); |
17a52670 AS |
5965 | return -EINVAL; |
5966 | } | |
5967 | ||
5968 | /* check src1 operand */ | |
dc503a8a | 5969 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
5970 | if (err) |
5971 | return err; | |
1be7f75d AS |
5972 | |
5973 | if (is_pointer_value(env, insn->src_reg)) { | |
61bd5218 | 5974 | verbose(env, "R%d pointer comparison prohibited\n", |
1be7f75d AS |
5975 | insn->src_reg); |
5976 | return -EACCES; | |
5977 | } | |
fb8d251e | 5978 | src_reg = ®s[insn->src_reg]; |
17a52670 AS |
5979 | } else { |
5980 | if (insn->src_reg != BPF_REG_0) { | |
092ed096 | 5981 | verbose(env, "BPF_JMP/JMP32 uses reserved fields\n"); |
17a52670 AS |
5982 | return -EINVAL; |
5983 | } | |
5984 | } | |
5985 | ||
5986 | /* check src2 operand */ | |
dc503a8a | 5987 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
5988 | if (err) |
5989 | return err; | |
5990 | ||
1a0dc1ac | 5991 | dst_reg = ®s[insn->dst_reg]; |
092ed096 | 5992 | is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32; |
1a0dc1ac | 5993 | |
fb8d251e AS |
5994 | if (BPF_SRC(insn->code) == BPF_K) |
5995 | pred = is_branch_taken(dst_reg, insn->imm, | |
5996 | opcode, is_jmp32); | |
5997 | else if (src_reg->type == SCALAR_VALUE && | |
5998 | tnum_is_const(src_reg->var_off)) | |
5999 | pred = is_branch_taken(dst_reg, src_reg->var_off.value, | |
6000 | opcode, is_jmp32); | |
b5dc0163 AS |
6001 | if (pred >= 0) { |
6002 | err = mark_chain_precision(env, insn->dst_reg); | |
6003 | if (BPF_SRC(insn->code) == BPF_X && !err) | |
6004 | err = mark_chain_precision(env, insn->src_reg); | |
6005 | if (err) | |
6006 | return err; | |
6007 | } | |
fb8d251e AS |
6008 | if (pred == 1) { |
6009 | /* only follow the goto, ignore fall-through */ | |
6010 | *insn_idx += insn->off; | |
6011 | return 0; | |
6012 | } else if (pred == 0) { | |
6013 | /* only follow fall-through branch, since | |
6014 | * that's where the program will go | |
6015 | */ | |
6016 | return 0; | |
17a52670 AS |
6017 | } |
6018 | ||
979d63d5 DB |
6019 | other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx, |
6020 | false); | |
17a52670 AS |
6021 | if (!other_branch) |
6022 | return -EFAULT; | |
f4d7e40a | 6023 | other_branch_regs = other_branch->frame[other_branch->curframe]->regs; |
17a52670 | 6024 | |
48461135 JB |
6025 | /* detect if we are comparing against a constant value so we can adjust |
6026 | * our min/max values for our dst register. | |
f1174f77 EC |
6027 | * this is only legit if both are scalars (or pointers to the same |
6028 | * object, I suppose, but we don't support that right now), because | |
6029 | * otherwise the different base pointers mean the offsets aren't | |
6030 | * comparable. | |
48461135 JB |
6031 | */ |
6032 | if (BPF_SRC(insn->code) == BPF_X) { | |
092ed096 JW |
6033 | struct bpf_reg_state *src_reg = ®s[insn->src_reg]; |
6034 | struct bpf_reg_state lo_reg0 = *dst_reg; | |
6035 | struct bpf_reg_state lo_reg1 = *src_reg; | |
6036 | struct bpf_reg_state *src_lo, *dst_lo; | |
6037 | ||
6038 | dst_lo = &lo_reg0; | |
6039 | src_lo = &lo_reg1; | |
6040 | coerce_reg_to_size(dst_lo, 4); | |
6041 | coerce_reg_to_size(src_lo, 4); | |
6042 | ||
f1174f77 | 6043 | if (dst_reg->type == SCALAR_VALUE && |
092ed096 JW |
6044 | src_reg->type == SCALAR_VALUE) { |
6045 | if (tnum_is_const(src_reg->var_off) || | |
6046 | (is_jmp32 && tnum_is_const(src_lo->var_off))) | |
f4d7e40a | 6047 | reg_set_min_max(&other_branch_regs[insn->dst_reg], |
092ed096 JW |
6048 | dst_reg, |
6049 | is_jmp32 | |
6050 | ? src_lo->var_off.value | |
6051 | : src_reg->var_off.value, | |
6052 | opcode, is_jmp32); | |
6053 | else if (tnum_is_const(dst_reg->var_off) || | |
6054 | (is_jmp32 && tnum_is_const(dst_lo->var_off))) | |
f4d7e40a | 6055 | reg_set_min_max_inv(&other_branch_regs[insn->src_reg], |
092ed096 JW |
6056 | src_reg, |
6057 | is_jmp32 | |
6058 | ? dst_lo->var_off.value | |
6059 | : dst_reg->var_off.value, | |
6060 | opcode, is_jmp32); | |
6061 | else if (!is_jmp32 && | |
6062 | (opcode == BPF_JEQ || opcode == BPF_JNE)) | |
f1174f77 | 6063 | /* Comparing for equality, we can combine knowledge */ |
f4d7e40a AS |
6064 | reg_combine_min_max(&other_branch_regs[insn->src_reg], |
6065 | &other_branch_regs[insn->dst_reg], | |
092ed096 | 6066 | src_reg, dst_reg, opcode); |
f1174f77 EC |
6067 | } |
6068 | } else if (dst_reg->type == SCALAR_VALUE) { | |
f4d7e40a | 6069 | reg_set_min_max(&other_branch_regs[insn->dst_reg], |
092ed096 | 6070 | dst_reg, insn->imm, opcode, is_jmp32); |
48461135 JB |
6071 | } |
6072 | ||
092ed096 JW |
6073 | /* detect if R == 0 where R is returned from bpf_map_lookup_elem(). |
6074 | * NOTE: these optimizations below are related with pointer comparison | |
6075 | * which will never be JMP32. | |
6076 | */ | |
6077 | if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K && | |
1a0dc1ac | 6078 | insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) && |
840b9615 JS |
6079 | reg_type_may_be_null(dst_reg->type)) { |
6080 | /* Mark all identical registers in each branch as either | |
57a09bf0 TG |
6081 | * safe or unknown depending R == 0 or R != 0 conditional. |
6082 | */ | |
840b9615 JS |
6083 | mark_ptr_or_null_regs(this_branch, insn->dst_reg, |
6084 | opcode == BPF_JNE); | |
6085 | mark_ptr_or_null_regs(other_branch, insn->dst_reg, | |
6086 | opcode == BPF_JEQ); | |
5beca081 DB |
6087 | } else if (!try_match_pkt_pointers(insn, dst_reg, ®s[insn->src_reg], |
6088 | this_branch, other_branch) && | |
6089 | is_pointer_value(env, insn->dst_reg)) { | |
61bd5218 JK |
6090 | verbose(env, "R%d pointer comparison prohibited\n", |
6091 | insn->dst_reg); | |
1be7f75d | 6092 | return -EACCES; |
17a52670 | 6093 | } |
06ee7115 | 6094 | if (env->log.level & BPF_LOG_LEVEL) |
f4d7e40a | 6095 | print_verifier_state(env, this_branch->frame[this_branch->curframe]); |
17a52670 AS |
6096 | return 0; |
6097 | } | |
6098 | ||
17a52670 | 6099 | /* verify BPF_LD_IMM64 instruction */ |
58e2af8b | 6100 | static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) |
17a52670 | 6101 | { |
d8eca5bb | 6102 | struct bpf_insn_aux_data *aux = cur_aux(env); |
638f5b90 | 6103 | struct bpf_reg_state *regs = cur_regs(env); |
d8eca5bb | 6104 | struct bpf_map *map; |
17a52670 AS |
6105 | int err; |
6106 | ||
6107 | if (BPF_SIZE(insn->code) != BPF_DW) { | |
61bd5218 | 6108 | verbose(env, "invalid BPF_LD_IMM insn\n"); |
17a52670 AS |
6109 | return -EINVAL; |
6110 | } | |
6111 | if (insn->off != 0) { | |
61bd5218 | 6112 | verbose(env, "BPF_LD_IMM64 uses reserved fields\n"); |
17a52670 AS |
6113 | return -EINVAL; |
6114 | } | |
6115 | ||
dc503a8a | 6116 | err = check_reg_arg(env, insn->dst_reg, DST_OP); |
17a52670 AS |
6117 | if (err) |
6118 | return err; | |
6119 | ||
6b173873 | 6120 | if (insn->src_reg == 0) { |
6b173873 JK |
6121 | u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; |
6122 | ||
f1174f77 | 6123 | regs[insn->dst_reg].type = SCALAR_VALUE; |
b03c9f9f | 6124 | __mark_reg_known(®s[insn->dst_reg], imm); |
17a52670 | 6125 | return 0; |
6b173873 | 6126 | } |
17a52670 | 6127 | |
d8eca5bb DB |
6128 | map = env->used_maps[aux->map_index]; |
6129 | mark_reg_known_zero(env, regs, insn->dst_reg); | |
6130 | regs[insn->dst_reg].map_ptr = map; | |
6131 | ||
6132 | if (insn->src_reg == BPF_PSEUDO_MAP_VALUE) { | |
6133 | regs[insn->dst_reg].type = PTR_TO_MAP_VALUE; | |
6134 | regs[insn->dst_reg].off = aux->map_off; | |
6135 | if (map_value_has_spin_lock(map)) | |
6136 | regs[insn->dst_reg].id = ++env->id_gen; | |
6137 | } else if (insn->src_reg == BPF_PSEUDO_MAP_FD) { | |
6138 | regs[insn->dst_reg].type = CONST_PTR_TO_MAP; | |
6139 | } else { | |
6140 | verbose(env, "bpf verifier is misconfigured\n"); | |
6141 | return -EINVAL; | |
6142 | } | |
17a52670 | 6143 | |
17a52670 AS |
6144 | return 0; |
6145 | } | |
6146 | ||
96be4325 DB |
6147 | static bool may_access_skb(enum bpf_prog_type type) |
6148 | { | |
6149 | switch (type) { | |
6150 | case BPF_PROG_TYPE_SOCKET_FILTER: | |
6151 | case BPF_PROG_TYPE_SCHED_CLS: | |
94caee8c | 6152 | case BPF_PROG_TYPE_SCHED_ACT: |
96be4325 DB |
6153 | return true; |
6154 | default: | |
6155 | return false; | |
6156 | } | |
6157 | } | |
6158 | ||
ddd872bc AS |
6159 | /* verify safety of LD_ABS|LD_IND instructions: |
6160 | * - they can only appear in the programs where ctx == skb | |
6161 | * - since they are wrappers of function calls, they scratch R1-R5 registers, | |
6162 | * preserve R6-R9, and store return value into R0 | |
6163 | * | |
6164 | * Implicit input: | |
6165 | * ctx == skb == R6 == CTX | |
6166 | * | |
6167 | * Explicit input: | |
6168 | * SRC == any register | |
6169 | * IMM == 32-bit immediate | |
6170 | * | |
6171 | * Output: | |
6172 | * R0 - 8/16/32-bit skb data converted to cpu endianness | |
6173 | */ | |
58e2af8b | 6174 | static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) |
ddd872bc | 6175 | { |
638f5b90 | 6176 | struct bpf_reg_state *regs = cur_regs(env); |
ddd872bc | 6177 | u8 mode = BPF_MODE(insn->code); |
ddd872bc AS |
6178 | int i, err; |
6179 | ||
24701ece | 6180 | if (!may_access_skb(env->prog->type)) { |
61bd5218 | 6181 | verbose(env, "BPF_LD_[ABS|IND] instructions not allowed for this program type\n"); |
ddd872bc AS |
6182 | return -EINVAL; |
6183 | } | |
6184 | ||
e0cea7ce DB |
6185 | if (!env->ops->gen_ld_abs) { |
6186 | verbose(env, "bpf verifier is misconfigured\n"); | |
6187 | return -EINVAL; | |
6188 | } | |
6189 | ||
f910cefa | 6190 | if (env->subprog_cnt > 1) { |
f4d7e40a AS |
6191 | /* when program has LD_ABS insn JITs and interpreter assume |
6192 | * that r1 == ctx == skb which is not the case for callees | |
6193 | * that can have arbitrary arguments. It's problematic | |
6194 | * for main prog as well since JITs would need to analyze | |
6195 | * all functions in order to make proper register save/restore | |
6196 | * decisions in the main prog. Hence disallow LD_ABS with calls | |
6197 | */ | |
6198 | verbose(env, "BPF_LD_[ABS|IND] instructions cannot be mixed with bpf-to-bpf calls\n"); | |
6199 | return -EINVAL; | |
6200 | } | |
6201 | ||
ddd872bc | 6202 | if (insn->dst_reg != BPF_REG_0 || insn->off != 0 || |
d82bccc6 | 6203 | BPF_SIZE(insn->code) == BPF_DW || |
ddd872bc | 6204 | (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) { |
61bd5218 | 6205 | verbose(env, "BPF_LD_[ABS|IND] uses reserved fields\n"); |
ddd872bc AS |
6206 | return -EINVAL; |
6207 | } | |
6208 | ||
6209 | /* check whether implicit source operand (register R6) is readable */ | |
dc503a8a | 6210 | err = check_reg_arg(env, BPF_REG_6, SRC_OP); |
ddd872bc AS |
6211 | if (err) |
6212 | return err; | |
6213 | ||
fd978bf7 JS |
6214 | /* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as |
6215 | * gen_ld_abs() may terminate the program at runtime, leading to | |
6216 | * reference leak. | |
6217 | */ | |
6218 | err = check_reference_leak(env); | |
6219 | if (err) { | |
6220 | verbose(env, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n"); | |
6221 | return err; | |
6222 | } | |
6223 | ||
d83525ca AS |
6224 | if (env->cur_state->active_spin_lock) { |
6225 | verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n"); | |
6226 | return -EINVAL; | |
6227 | } | |
6228 | ||
ddd872bc | 6229 | if (regs[BPF_REG_6].type != PTR_TO_CTX) { |
61bd5218 JK |
6230 | verbose(env, |
6231 | "at the time of BPF_LD_ABS|IND R6 != pointer to skb\n"); | |
ddd872bc AS |
6232 | return -EINVAL; |
6233 | } | |
6234 | ||
6235 | if (mode == BPF_IND) { | |
6236 | /* check explicit source operand */ | |
dc503a8a | 6237 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
ddd872bc AS |
6238 | if (err) |
6239 | return err; | |
6240 | } | |
6241 | ||
6242 | /* reset caller saved regs to unreadable */ | |
dc503a8a | 6243 | for (i = 0; i < CALLER_SAVED_REGS; i++) { |
61bd5218 | 6244 | mark_reg_not_init(env, regs, caller_saved[i]); |
dc503a8a EC |
6245 | check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK); |
6246 | } | |
ddd872bc AS |
6247 | |
6248 | /* mark destination R0 register as readable, since it contains | |
dc503a8a EC |
6249 | * the value fetched from the packet. |
6250 | * Already marked as written above. | |
ddd872bc | 6251 | */ |
61bd5218 | 6252 | mark_reg_unknown(env, regs, BPF_REG_0); |
5327ed3d JW |
6253 | /* ld_abs load up to 32-bit skb data. */ |
6254 | regs[BPF_REG_0].subreg_def = env->insn_idx + 1; | |
ddd872bc AS |
6255 | return 0; |
6256 | } | |
6257 | ||
390ee7e2 AS |
6258 | static int check_return_code(struct bpf_verifier_env *env) |
6259 | { | |
5cf1e914 | 6260 | struct tnum enforce_attach_type_range = tnum_unknown; |
390ee7e2 AS |
6261 | struct bpf_reg_state *reg; |
6262 | struct tnum range = tnum_range(0, 1); | |
6263 | ||
6264 | switch (env->prog->type) { | |
983695fa DB |
6265 | case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: |
6266 | if (env->prog->expected_attach_type == BPF_CGROUP_UDP4_RECVMSG || | |
6267 | env->prog->expected_attach_type == BPF_CGROUP_UDP6_RECVMSG) | |
6268 | range = tnum_range(1, 1); | |
ed4ed404 | 6269 | break; |
390ee7e2 | 6270 | case BPF_PROG_TYPE_CGROUP_SKB: |
5cf1e914 | 6271 | if (env->prog->expected_attach_type == BPF_CGROUP_INET_EGRESS) { |
6272 | range = tnum_range(0, 3); | |
6273 | enforce_attach_type_range = tnum_range(2, 3); | |
6274 | } | |
ed4ed404 | 6275 | break; |
390ee7e2 AS |
6276 | case BPF_PROG_TYPE_CGROUP_SOCK: |
6277 | case BPF_PROG_TYPE_SOCK_OPS: | |
ebc614f6 | 6278 | case BPF_PROG_TYPE_CGROUP_DEVICE: |
7b146ceb | 6279 | case BPF_PROG_TYPE_CGROUP_SYSCTL: |
0d01da6a | 6280 | case BPF_PROG_TYPE_CGROUP_SOCKOPT: |
390ee7e2 AS |
6281 | break; |
6282 | default: | |
6283 | return 0; | |
6284 | } | |
6285 | ||
638f5b90 | 6286 | reg = cur_regs(env) + BPF_REG_0; |
390ee7e2 | 6287 | if (reg->type != SCALAR_VALUE) { |
61bd5218 | 6288 | verbose(env, "At program exit the register R0 is not a known value (%s)\n", |
390ee7e2 AS |
6289 | reg_type_str[reg->type]); |
6290 | return -EINVAL; | |
6291 | } | |
6292 | ||
6293 | if (!tnum_in(range, reg->var_off)) { | |
5cf1e914 | 6294 | char tn_buf[48]; |
6295 | ||
61bd5218 | 6296 | verbose(env, "At program exit the register R0 "); |
390ee7e2 | 6297 | if (!tnum_is_unknown(reg->var_off)) { |
390ee7e2 | 6298 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); |
61bd5218 | 6299 | verbose(env, "has value %s", tn_buf); |
390ee7e2 | 6300 | } else { |
61bd5218 | 6301 | verbose(env, "has unknown scalar value"); |
390ee7e2 | 6302 | } |
5cf1e914 | 6303 | tnum_strn(tn_buf, sizeof(tn_buf), range); |
983695fa | 6304 | verbose(env, " should have been in %s\n", tn_buf); |
390ee7e2 AS |
6305 | return -EINVAL; |
6306 | } | |
5cf1e914 | 6307 | |
6308 | if (!tnum_is_unknown(enforce_attach_type_range) && | |
6309 | tnum_in(enforce_attach_type_range, reg->var_off)) | |
6310 | env->prog->enforce_expected_attach_type = 1; | |
390ee7e2 AS |
6311 | return 0; |
6312 | } | |
6313 | ||
475fb78f AS |
6314 | /* non-recursive DFS pseudo code |
6315 | * 1 procedure DFS-iterative(G,v): | |
6316 | * 2 label v as discovered | |
6317 | * 3 let S be a stack | |
6318 | * 4 S.push(v) | |
6319 | * 5 while S is not empty | |
6320 | * 6 t <- S.pop() | |
6321 | * 7 if t is what we're looking for: | |
6322 | * 8 return t | |
6323 | * 9 for all edges e in G.adjacentEdges(t) do | |
6324 | * 10 if edge e is already labelled | |
6325 | * 11 continue with the next edge | |
6326 | * 12 w <- G.adjacentVertex(t,e) | |
6327 | * 13 if vertex w is not discovered and not explored | |
6328 | * 14 label e as tree-edge | |
6329 | * 15 label w as discovered | |
6330 | * 16 S.push(w) | |
6331 | * 17 continue at 5 | |
6332 | * 18 else if vertex w is discovered | |
6333 | * 19 label e as back-edge | |
6334 | * 20 else | |
6335 | * 21 // vertex w is explored | |
6336 | * 22 label e as forward- or cross-edge | |
6337 | * 23 label t as explored | |
6338 | * 24 S.pop() | |
6339 | * | |
6340 | * convention: | |
6341 | * 0x10 - discovered | |
6342 | * 0x11 - discovered and fall-through edge labelled | |
6343 | * 0x12 - discovered and fall-through and branch edges labelled | |
6344 | * 0x20 - explored | |
6345 | */ | |
6346 | ||
6347 | enum { | |
6348 | DISCOVERED = 0x10, | |
6349 | EXPLORED = 0x20, | |
6350 | FALLTHROUGH = 1, | |
6351 | BRANCH = 2, | |
6352 | }; | |
6353 | ||
dc2a4ebc AS |
6354 | static u32 state_htab_size(struct bpf_verifier_env *env) |
6355 | { | |
6356 | return env->prog->len; | |
6357 | } | |
6358 | ||
5d839021 AS |
6359 | static struct bpf_verifier_state_list **explored_state( |
6360 | struct bpf_verifier_env *env, | |
6361 | int idx) | |
6362 | { | |
dc2a4ebc AS |
6363 | struct bpf_verifier_state *cur = env->cur_state; |
6364 | struct bpf_func_state *state = cur->frame[cur->curframe]; | |
6365 | ||
6366 | return &env->explored_states[(idx ^ state->callsite) % state_htab_size(env)]; | |
5d839021 AS |
6367 | } |
6368 | ||
6369 | static void init_explored_state(struct bpf_verifier_env *env, int idx) | |
6370 | { | |
a8f500af | 6371 | env->insn_aux_data[idx].prune_point = true; |
5d839021 | 6372 | } |
f1bca824 | 6373 | |
475fb78f AS |
6374 | /* t, w, e - match pseudo-code above: |
6375 | * t - index of current instruction | |
6376 | * w - next instruction | |
6377 | * e - edge | |
6378 | */ | |
2589726d AS |
6379 | static int push_insn(int t, int w, int e, struct bpf_verifier_env *env, |
6380 | bool loop_ok) | |
475fb78f | 6381 | { |
7df737e9 AS |
6382 | int *insn_stack = env->cfg.insn_stack; |
6383 | int *insn_state = env->cfg.insn_state; | |
6384 | ||
475fb78f AS |
6385 | if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH)) |
6386 | return 0; | |
6387 | ||
6388 | if (e == BRANCH && insn_state[t] >= (DISCOVERED | BRANCH)) | |
6389 | return 0; | |
6390 | ||
6391 | if (w < 0 || w >= env->prog->len) { | |
d9762e84 | 6392 | verbose_linfo(env, t, "%d: ", t); |
61bd5218 | 6393 | verbose(env, "jump out of range from insn %d to %d\n", t, w); |
475fb78f AS |
6394 | return -EINVAL; |
6395 | } | |
6396 | ||
f1bca824 AS |
6397 | if (e == BRANCH) |
6398 | /* mark branch target for state pruning */ | |
5d839021 | 6399 | init_explored_state(env, w); |
f1bca824 | 6400 | |
475fb78f AS |
6401 | if (insn_state[w] == 0) { |
6402 | /* tree-edge */ | |
6403 | insn_state[t] = DISCOVERED | e; | |
6404 | insn_state[w] = DISCOVERED; | |
7df737e9 | 6405 | if (env->cfg.cur_stack >= env->prog->len) |
475fb78f | 6406 | return -E2BIG; |
7df737e9 | 6407 | insn_stack[env->cfg.cur_stack++] = w; |
475fb78f AS |
6408 | return 1; |
6409 | } else if ((insn_state[w] & 0xF0) == DISCOVERED) { | |
2589726d AS |
6410 | if (loop_ok && env->allow_ptr_leaks) |
6411 | return 0; | |
d9762e84 MKL |
6412 | verbose_linfo(env, t, "%d: ", t); |
6413 | verbose_linfo(env, w, "%d: ", w); | |
61bd5218 | 6414 | verbose(env, "back-edge from insn %d to %d\n", t, w); |
475fb78f AS |
6415 | return -EINVAL; |
6416 | } else if (insn_state[w] == EXPLORED) { | |
6417 | /* forward- or cross-edge */ | |
6418 | insn_state[t] = DISCOVERED | e; | |
6419 | } else { | |
61bd5218 | 6420 | verbose(env, "insn state internal bug\n"); |
475fb78f AS |
6421 | return -EFAULT; |
6422 | } | |
6423 | return 0; | |
6424 | } | |
6425 | ||
6426 | /* non-recursive depth-first-search to detect loops in BPF program | |
6427 | * loop == back-edge in directed graph | |
6428 | */ | |
58e2af8b | 6429 | static int check_cfg(struct bpf_verifier_env *env) |
475fb78f AS |
6430 | { |
6431 | struct bpf_insn *insns = env->prog->insnsi; | |
6432 | int insn_cnt = env->prog->len; | |
7df737e9 | 6433 | int *insn_stack, *insn_state; |
475fb78f AS |
6434 | int ret = 0; |
6435 | int i, t; | |
6436 | ||
7df737e9 | 6437 | insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL); |
475fb78f AS |
6438 | if (!insn_state) |
6439 | return -ENOMEM; | |
6440 | ||
7df737e9 | 6441 | insn_stack = env->cfg.insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL); |
475fb78f | 6442 | if (!insn_stack) { |
71dde681 | 6443 | kvfree(insn_state); |
475fb78f AS |
6444 | return -ENOMEM; |
6445 | } | |
6446 | ||
6447 | insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */ | |
6448 | insn_stack[0] = 0; /* 0 is the first instruction */ | |
7df737e9 | 6449 | env->cfg.cur_stack = 1; |
475fb78f AS |
6450 | |
6451 | peek_stack: | |
7df737e9 | 6452 | if (env->cfg.cur_stack == 0) |
475fb78f | 6453 | goto check_state; |
7df737e9 | 6454 | t = insn_stack[env->cfg.cur_stack - 1]; |
475fb78f | 6455 | |
092ed096 JW |
6456 | if (BPF_CLASS(insns[t].code) == BPF_JMP || |
6457 | BPF_CLASS(insns[t].code) == BPF_JMP32) { | |
475fb78f AS |
6458 | u8 opcode = BPF_OP(insns[t].code); |
6459 | ||
6460 | if (opcode == BPF_EXIT) { | |
6461 | goto mark_explored; | |
6462 | } else if (opcode == BPF_CALL) { | |
2589726d | 6463 | ret = push_insn(t, t + 1, FALLTHROUGH, env, false); |
475fb78f AS |
6464 | if (ret == 1) |
6465 | goto peek_stack; | |
6466 | else if (ret < 0) | |
6467 | goto err_free; | |
07016151 | 6468 | if (t + 1 < insn_cnt) |
5d839021 | 6469 | init_explored_state(env, t + 1); |
cc8b0b92 | 6470 | if (insns[t].src_reg == BPF_PSEUDO_CALL) { |
5d839021 | 6471 | init_explored_state(env, t); |
2589726d AS |
6472 | ret = push_insn(t, t + insns[t].imm + 1, BRANCH, |
6473 | env, false); | |
cc8b0b92 AS |
6474 | if (ret == 1) |
6475 | goto peek_stack; | |
6476 | else if (ret < 0) | |
6477 | goto err_free; | |
6478 | } | |
475fb78f AS |
6479 | } else if (opcode == BPF_JA) { |
6480 | if (BPF_SRC(insns[t].code) != BPF_K) { | |
6481 | ret = -EINVAL; | |
6482 | goto err_free; | |
6483 | } | |
6484 | /* unconditional jump with single edge */ | |
6485 | ret = push_insn(t, t + insns[t].off + 1, | |
2589726d | 6486 | FALLTHROUGH, env, true); |
475fb78f AS |
6487 | if (ret == 1) |
6488 | goto peek_stack; | |
6489 | else if (ret < 0) | |
6490 | goto err_free; | |
b5dc0163 AS |
6491 | /* unconditional jmp is not a good pruning point, |
6492 | * but it's marked, since backtracking needs | |
6493 | * to record jmp history in is_state_visited(). | |
6494 | */ | |
6495 | init_explored_state(env, t + insns[t].off + 1); | |
f1bca824 AS |
6496 | /* tell verifier to check for equivalent states |
6497 | * after every call and jump | |
6498 | */ | |
c3de6317 | 6499 | if (t + 1 < insn_cnt) |
5d839021 | 6500 | init_explored_state(env, t + 1); |
475fb78f AS |
6501 | } else { |
6502 | /* conditional jump with two edges */ | |
5d839021 | 6503 | init_explored_state(env, t); |
2589726d | 6504 | ret = push_insn(t, t + 1, FALLTHROUGH, env, true); |
475fb78f AS |
6505 | if (ret == 1) |
6506 | goto peek_stack; | |
6507 | else if (ret < 0) | |
6508 | goto err_free; | |
6509 | ||
2589726d | 6510 | ret = push_insn(t, t + insns[t].off + 1, BRANCH, env, true); |
475fb78f AS |
6511 | if (ret == 1) |
6512 | goto peek_stack; | |
6513 | else if (ret < 0) | |
6514 | goto err_free; | |
6515 | } | |
6516 | } else { | |
6517 | /* all other non-branch instructions with single | |
6518 | * fall-through edge | |
6519 | */ | |
2589726d | 6520 | ret = push_insn(t, t + 1, FALLTHROUGH, env, false); |
475fb78f AS |
6521 | if (ret == 1) |
6522 | goto peek_stack; | |
6523 | else if (ret < 0) | |
6524 | goto err_free; | |
6525 | } | |
6526 | ||
6527 | mark_explored: | |
6528 | insn_state[t] = EXPLORED; | |
7df737e9 | 6529 | if (env->cfg.cur_stack-- <= 0) { |
61bd5218 | 6530 | verbose(env, "pop stack internal bug\n"); |
475fb78f AS |
6531 | ret = -EFAULT; |
6532 | goto err_free; | |
6533 | } | |
6534 | goto peek_stack; | |
6535 | ||
6536 | check_state: | |
6537 | for (i = 0; i < insn_cnt; i++) { | |
6538 | if (insn_state[i] != EXPLORED) { | |
61bd5218 | 6539 | verbose(env, "unreachable insn %d\n", i); |
475fb78f AS |
6540 | ret = -EINVAL; |
6541 | goto err_free; | |
6542 | } | |
6543 | } | |
6544 | ret = 0; /* cfg looks good */ | |
6545 | ||
6546 | err_free: | |
71dde681 AS |
6547 | kvfree(insn_state); |
6548 | kvfree(insn_stack); | |
7df737e9 | 6549 | env->cfg.insn_state = env->cfg.insn_stack = NULL; |
475fb78f AS |
6550 | return ret; |
6551 | } | |
6552 | ||
838e9690 YS |
6553 | /* The minimum supported BTF func info size */ |
6554 | #define MIN_BPF_FUNCINFO_SIZE 8 | |
6555 | #define MAX_FUNCINFO_REC_SIZE 252 | |
6556 | ||
c454a46b MKL |
6557 | static int check_btf_func(struct bpf_verifier_env *env, |
6558 | const union bpf_attr *attr, | |
6559 | union bpf_attr __user *uattr) | |
838e9690 | 6560 | { |
d0b2818e | 6561 | u32 i, nfuncs, urec_size, min_size; |
838e9690 | 6562 | u32 krec_size = sizeof(struct bpf_func_info); |
c454a46b | 6563 | struct bpf_func_info *krecord; |
838e9690 | 6564 | const struct btf_type *type; |
c454a46b MKL |
6565 | struct bpf_prog *prog; |
6566 | const struct btf *btf; | |
838e9690 | 6567 | void __user *urecord; |
d0b2818e | 6568 | u32 prev_offset = 0; |
838e9690 YS |
6569 | int ret = 0; |
6570 | ||
6571 | nfuncs = attr->func_info_cnt; | |
6572 | if (!nfuncs) | |
6573 | return 0; | |
6574 | ||
6575 | if (nfuncs != env->subprog_cnt) { | |
6576 | verbose(env, "number of funcs in func_info doesn't match number of subprogs\n"); | |
6577 | return -EINVAL; | |
6578 | } | |
6579 | ||
6580 | urec_size = attr->func_info_rec_size; | |
6581 | if (urec_size < MIN_BPF_FUNCINFO_SIZE || | |
6582 | urec_size > MAX_FUNCINFO_REC_SIZE || | |
6583 | urec_size % sizeof(u32)) { | |
6584 | verbose(env, "invalid func info rec size %u\n", urec_size); | |
6585 | return -EINVAL; | |
6586 | } | |
6587 | ||
c454a46b MKL |
6588 | prog = env->prog; |
6589 | btf = prog->aux->btf; | |
838e9690 YS |
6590 | |
6591 | urecord = u64_to_user_ptr(attr->func_info); | |
6592 | min_size = min_t(u32, krec_size, urec_size); | |
6593 | ||
ba64e7d8 | 6594 | krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN); |
c454a46b MKL |
6595 | if (!krecord) |
6596 | return -ENOMEM; | |
ba64e7d8 | 6597 | |
838e9690 YS |
6598 | for (i = 0; i < nfuncs; i++) { |
6599 | ret = bpf_check_uarg_tail_zero(urecord, krec_size, urec_size); | |
6600 | if (ret) { | |
6601 | if (ret == -E2BIG) { | |
6602 | verbose(env, "nonzero tailing record in func info"); | |
6603 | /* set the size kernel expects so loader can zero | |
6604 | * out the rest of the record. | |
6605 | */ | |
6606 | if (put_user(min_size, &uattr->func_info_rec_size)) | |
6607 | ret = -EFAULT; | |
6608 | } | |
c454a46b | 6609 | goto err_free; |
838e9690 YS |
6610 | } |
6611 | ||
ba64e7d8 | 6612 | if (copy_from_user(&krecord[i], urecord, min_size)) { |
838e9690 | 6613 | ret = -EFAULT; |
c454a46b | 6614 | goto err_free; |
838e9690 YS |
6615 | } |
6616 | ||
d30d42e0 | 6617 | /* check insn_off */ |
838e9690 | 6618 | if (i == 0) { |
d30d42e0 | 6619 | if (krecord[i].insn_off) { |
838e9690 | 6620 | verbose(env, |
d30d42e0 MKL |
6621 | "nonzero insn_off %u for the first func info record", |
6622 | krecord[i].insn_off); | |
838e9690 | 6623 | ret = -EINVAL; |
c454a46b | 6624 | goto err_free; |
838e9690 | 6625 | } |
d30d42e0 | 6626 | } else if (krecord[i].insn_off <= prev_offset) { |
838e9690 YS |
6627 | verbose(env, |
6628 | "same or smaller insn offset (%u) than previous func info record (%u)", | |
d30d42e0 | 6629 | krecord[i].insn_off, prev_offset); |
838e9690 | 6630 | ret = -EINVAL; |
c454a46b | 6631 | goto err_free; |
838e9690 YS |
6632 | } |
6633 | ||
d30d42e0 | 6634 | if (env->subprog_info[i].start != krecord[i].insn_off) { |
838e9690 YS |
6635 | verbose(env, "func_info BTF section doesn't match subprog layout in BPF program\n"); |
6636 | ret = -EINVAL; | |
c454a46b | 6637 | goto err_free; |
838e9690 YS |
6638 | } |
6639 | ||
6640 | /* check type_id */ | |
ba64e7d8 | 6641 | type = btf_type_by_id(btf, krecord[i].type_id); |
838e9690 YS |
6642 | if (!type || BTF_INFO_KIND(type->info) != BTF_KIND_FUNC) { |
6643 | verbose(env, "invalid type id %d in func info", | |
ba64e7d8 | 6644 | krecord[i].type_id); |
838e9690 | 6645 | ret = -EINVAL; |
c454a46b | 6646 | goto err_free; |
838e9690 YS |
6647 | } |
6648 | ||
d30d42e0 | 6649 | prev_offset = krecord[i].insn_off; |
838e9690 YS |
6650 | urecord += urec_size; |
6651 | } | |
6652 | ||
ba64e7d8 YS |
6653 | prog->aux->func_info = krecord; |
6654 | prog->aux->func_info_cnt = nfuncs; | |
838e9690 YS |
6655 | return 0; |
6656 | ||
c454a46b | 6657 | err_free: |
ba64e7d8 | 6658 | kvfree(krecord); |
838e9690 YS |
6659 | return ret; |
6660 | } | |
6661 | ||
ba64e7d8 YS |
6662 | static void adjust_btf_func(struct bpf_verifier_env *env) |
6663 | { | |
6664 | int i; | |
6665 | ||
6666 | if (!env->prog->aux->func_info) | |
6667 | return; | |
6668 | ||
6669 | for (i = 0; i < env->subprog_cnt; i++) | |
d30d42e0 | 6670 | env->prog->aux->func_info[i].insn_off = env->subprog_info[i].start; |
ba64e7d8 YS |
6671 | } |
6672 | ||
c454a46b MKL |
6673 | #define MIN_BPF_LINEINFO_SIZE (offsetof(struct bpf_line_info, line_col) + \ |
6674 | sizeof(((struct bpf_line_info *)(0))->line_col)) | |
6675 | #define MAX_LINEINFO_REC_SIZE MAX_FUNCINFO_REC_SIZE | |
6676 | ||
6677 | static int check_btf_line(struct bpf_verifier_env *env, | |
6678 | const union bpf_attr *attr, | |
6679 | union bpf_attr __user *uattr) | |
6680 | { | |
6681 | u32 i, s, nr_linfo, ncopy, expected_size, rec_size, prev_offset = 0; | |
6682 | struct bpf_subprog_info *sub; | |
6683 | struct bpf_line_info *linfo; | |
6684 | struct bpf_prog *prog; | |
6685 | const struct btf *btf; | |
6686 | void __user *ulinfo; | |
6687 | int err; | |
6688 | ||
6689 | nr_linfo = attr->line_info_cnt; | |
6690 | if (!nr_linfo) | |
6691 | return 0; | |
6692 | ||
6693 | rec_size = attr->line_info_rec_size; | |
6694 | if (rec_size < MIN_BPF_LINEINFO_SIZE || | |
6695 | rec_size > MAX_LINEINFO_REC_SIZE || | |
6696 | rec_size & (sizeof(u32) - 1)) | |
6697 | return -EINVAL; | |
6698 | ||
6699 | /* Need to zero it in case the userspace may | |
6700 | * pass in a smaller bpf_line_info object. | |
6701 | */ | |
6702 | linfo = kvcalloc(nr_linfo, sizeof(struct bpf_line_info), | |
6703 | GFP_KERNEL | __GFP_NOWARN); | |
6704 | if (!linfo) | |
6705 | return -ENOMEM; | |
6706 | ||
6707 | prog = env->prog; | |
6708 | btf = prog->aux->btf; | |
6709 | ||
6710 | s = 0; | |
6711 | sub = env->subprog_info; | |
6712 | ulinfo = u64_to_user_ptr(attr->line_info); | |
6713 | expected_size = sizeof(struct bpf_line_info); | |
6714 | ncopy = min_t(u32, expected_size, rec_size); | |
6715 | for (i = 0; i < nr_linfo; i++) { | |
6716 | err = bpf_check_uarg_tail_zero(ulinfo, expected_size, rec_size); | |
6717 | if (err) { | |
6718 | if (err == -E2BIG) { | |
6719 | verbose(env, "nonzero tailing record in line_info"); | |
6720 | if (put_user(expected_size, | |
6721 | &uattr->line_info_rec_size)) | |
6722 | err = -EFAULT; | |
6723 | } | |
6724 | goto err_free; | |
6725 | } | |
6726 | ||
6727 | if (copy_from_user(&linfo[i], ulinfo, ncopy)) { | |
6728 | err = -EFAULT; | |
6729 | goto err_free; | |
6730 | } | |
6731 | ||
6732 | /* | |
6733 | * Check insn_off to ensure | |
6734 | * 1) strictly increasing AND | |
6735 | * 2) bounded by prog->len | |
6736 | * | |
6737 | * The linfo[0].insn_off == 0 check logically falls into | |
6738 | * the later "missing bpf_line_info for func..." case | |
6739 | * because the first linfo[0].insn_off must be the | |
6740 | * first sub also and the first sub must have | |
6741 | * subprog_info[0].start == 0. | |
6742 | */ | |
6743 | if ((i && linfo[i].insn_off <= prev_offset) || | |
6744 | linfo[i].insn_off >= prog->len) { | |
6745 | verbose(env, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n", | |
6746 | i, linfo[i].insn_off, prev_offset, | |
6747 | prog->len); | |
6748 | err = -EINVAL; | |
6749 | goto err_free; | |
6750 | } | |
6751 | ||
fdbaa0be MKL |
6752 | if (!prog->insnsi[linfo[i].insn_off].code) { |
6753 | verbose(env, | |
6754 | "Invalid insn code at line_info[%u].insn_off\n", | |
6755 | i); | |
6756 | err = -EINVAL; | |
6757 | goto err_free; | |
6758 | } | |
6759 | ||
23127b33 MKL |
6760 | if (!btf_name_by_offset(btf, linfo[i].line_off) || |
6761 | !btf_name_by_offset(btf, linfo[i].file_name_off)) { | |
c454a46b MKL |
6762 | verbose(env, "Invalid line_info[%u].line_off or .file_name_off\n", i); |
6763 | err = -EINVAL; | |
6764 | goto err_free; | |
6765 | } | |
6766 | ||
6767 | if (s != env->subprog_cnt) { | |
6768 | if (linfo[i].insn_off == sub[s].start) { | |
6769 | sub[s].linfo_idx = i; | |
6770 | s++; | |
6771 | } else if (sub[s].start < linfo[i].insn_off) { | |
6772 | verbose(env, "missing bpf_line_info for func#%u\n", s); | |
6773 | err = -EINVAL; | |
6774 | goto err_free; | |
6775 | } | |
6776 | } | |
6777 | ||
6778 | prev_offset = linfo[i].insn_off; | |
6779 | ulinfo += rec_size; | |
6780 | } | |
6781 | ||
6782 | if (s != env->subprog_cnt) { | |
6783 | verbose(env, "missing bpf_line_info for %u funcs starting from func#%u\n", | |
6784 | env->subprog_cnt - s, s); | |
6785 | err = -EINVAL; | |
6786 | goto err_free; | |
6787 | } | |
6788 | ||
6789 | prog->aux->linfo = linfo; | |
6790 | prog->aux->nr_linfo = nr_linfo; | |
6791 | ||
6792 | return 0; | |
6793 | ||
6794 | err_free: | |
6795 | kvfree(linfo); | |
6796 | return err; | |
6797 | } | |
6798 | ||
6799 | static int check_btf_info(struct bpf_verifier_env *env, | |
6800 | const union bpf_attr *attr, | |
6801 | union bpf_attr __user *uattr) | |
6802 | { | |
6803 | struct btf *btf; | |
6804 | int err; | |
6805 | ||
6806 | if (!attr->func_info_cnt && !attr->line_info_cnt) | |
6807 | return 0; | |
6808 | ||
6809 | btf = btf_get_by_fd(attr->prog_btf_fd); | |
6810 | if (IS_ERR(btf)) | |
6811 | return PTR_ERR(btf); | |
6812 | env->prog->aux->btf = btf; | |
6813 | ||
6814 | err = check_btf_func(env, attr, uattr); | |
6815 | if (err) | |
6816 | return err; | |
6817 | ||
6818 | err = check_btf_line(env, attr, uattr); | |
6819 | if (err) | |
6820 | return err; | |
6821 | ||
6822 | return 0; | |
ba64e7d8 YS |
6823 | } |
6824 | ||
f1174f77 EC |
6825 | /* check %cur's range satisfies %old's */ |
6826 | static bool range_within(struct bpf_reg_state *old, | |
6827 | struct bpf_reg_state *cur) | |
6828 | { | |
b03c9f9f EC |
6829 | return old->umin_value <= cur->umin_value && |
6830 | old->umax_value >= cur->umax_value && | |
6831 | old->smin_value <= cur->smin_value && | |
6832 | old->smax_value >= cur->smax_value; | |
f1174f77 EC |
6833 | } |
6834 | ||
6835 | /* Maximum number of register states that can exist at once */ | |
6836 | #define ID_MAP_SIZE (MAX_BPF_REG + MAX_BPF_STACK / BPF_REG_SIZE) | |
6837 | struct idpair { | |
6838 | u32 old; | |
6839 | u32 cur; | |
6840 | }; | |
6841 | ||
6842 | /* If in the old state two registers had the same id, then they need to have | |
6843 | * the same id in the new state as well. But that id could be different from | |
6844 | * the old state, so we need to track the mapping from old to new ids. | |
6845 | * Once we have seen that, say, a reg with old id 5 had new id 9, any subsequent | |
6846 | * regs with old id 5 must also have new id 9 for the new state to be safe. But | |
6847 | * regs with a different old id could still have new id 9, we don't care about | |
6848 | * that. | |
6849 | * So we look through our idmap to see if this old id has been seen before. If | |
6850 | * so, we require the new id to match; otherwise, we add the id pair to the map. | |
969bf05e | 6851 | */ |
f1174f77 | 6852 | static bool check_ids(u32 old_id, u32 cur_id, struct idpair *idmap) |
969bf05e | 6853 | { |
f1174f77 | 6854 | unsigned int i; |
969bf05e | 6855 | |
f1174f77 EC |
6856 | for (i = 0; i < ID_MAP_SIZE; i++) { |
6857 | if (!idmap[i].old) { | |
6858 | /* Reached an empty slot; haven't seen this id before */ | |
6859 | idmap[i].old = old_id; | |
6860 | idmap[i].cur = cur_id; | |
6861 | return true; | |
6862 | } | |
6863 | if (idmap[i].old == old_id) | |
6864 | return idmap[i].cur == cur_id; | |
6865 | } | |
6866 | /* We ran out of idmap slots, which should be impossible */ | |
6867 | WARN_ON_ONCE(1); | |
6868 | return false; | |
6869 | } | |
6870 | ||
9242b5f5 AS |
6871 | static void clean_func_state(struct bpf_verifier_env *env, |
6872 | struct bpf_func_state *st) | |
6873 | { | |
6874 | enum bpf_reg_liveness live; | |
6875 | int i, j; | |
6876 | ||
6877 | for (i = 0; i < BPF_REG_FP; i++) { | |
6878 | live = st->regs[i].live; | |
6879 | /* liveness must not touch this register anymore */ | |
6880 | st->regs[i].live |= REG_LIVE_DONE; | |
6881 | if (!(live & REG_LIVE_READ)) | |
6882 | /* since the register is unused, clear its state | |
6883 | * to make further comparison simpler | |
6884 | */ | |
6885 | __mark_reg_not_init(&st->regs[i]); | |
6886 | } | |
6887 | ||
6888 | for (i = 0; i < st->allocated_stack / BPF_REG_SIZE; i++) { | |
6889 | live = st->stack[i].spilled_ptr.live; | |
6890 | /* liveness must not touch this stack slot anymore */ | |
6891 | st->stack[i].spilled_ptr.live |= REG_LIVE_DONE; | |
6892 | if (!(live & REG_LIVE_READ)) { | |
6893 | __mark_reg_not_init(&st->stack[i].spilled_ptr); | |
6894 | for (j = 0; j < BPF_REG_SIZE; j++) | |
6895 | st->stack[i].slot_type[j] = STACK_INVALID; | |
6896 | } | |
6897 | } | |
6898 | } | |
6899 | ||
6900 | static void clean_verifier_state(struct bpf_verifier_env *env, | |
6901 | struct bpf_verifier_state *st) | |
6902 | { | |
6903 | int i; | |
6904 | ||
6905 | if (st->frame[0]->regs[0].live & REG_LIVE_DONE) | |
6906 | /* all regs in this state in all frames were already marked */ | |
6907 | return; | |
6908 | ||
6909 | for (i = 0; i <= st->curframe; i++) | |
6910 | clean_func_state(env, st->frame[i]); | |
6911 | } | |
6912 | ||
6913 | /* the parentage chains form a tree. | |
6914 | * the verifier states are added to state lists at given insn and | |
6915 | * pushed into state stack for future exploration. | |
6916 | * when the verifier reaches bpf_exit insn some of the verifer states | |
6917 | * stored in the state lists have their final liveness state already, | |
6918 | * but a lot of states will get revised from liveness point of view when | |
6919 | * the verifier explores other branches. | |
6920 | * Example: | |
6921 | * 1: r0 = 1 | |
6922 | * 2: if r1 == 100 goto pc+1 | |
6923 | * 3: r0 = 2 | |
6924 | * 4: exit | |
6925 | * when the verifier reaches exit insn the register r0 in the state list of | |
6926 | * insn 2 will be seen as !REG_LIVE_READ. Then the verifier pops the other_branch | |
6927 | * of insn 2 and goes exploring further. At the insn 4 it will walk the | |
6928 | * parentage chain from insn 4 into insn 2 and will mark r0 as REG_LIVE_READ. | |
6929 | * | |
6930 | * Since the verifier pushes the branch states as it sees them while exploring | |
6931 | * the program the condition of walking the branch instruction for the second | |
6932 | * time means that all states below this branch were already explored and | |
6933 | * their final liveness markes are already propagated. | |
6934 | * Hence when the verifier completes the search of state list in is_state_visited() | |
6935 | * we can call this clean_live_states() function to mark all liveness states | |
6936 | * as REG_LIVE_DONE to indicate that 'parent' pointers of 'struct bpf_reg_state' | |
6937 | * will not be used. | |
6938 | * This function also clears the registers and stack for states that !READ | |
6939 | * to simplify state merging. | |
6940 | * | |
6941 | * Important note here that walking the same branch instruction in the callee | |
6942 | * doesn't meant that the states are DONE. The verifier has to compare | |
6943 | * the callsites | |
6944 | */ | |
6945 | static void clean_live_states(struct bpf_verifier_env *env, int insn, | |
6946 | struct bpf_verifier_state *cur) | |
6947 | { | |
6948 | struct bpf_verifier_state_list *sl; | |
6949 | int i; | |
6950 | ||
5d839021 | 6951 | sl = *explored_state(env, insn); |
a8f500af | 6952 | while (sl) { |
2589726d AS |
6953 | if (sl->state.branches) |
6954 | goto next; | |
dc2a4ebc AS |
6955 | if (sl->state.insn_idx != insn || |
6956 | sl->state.curframe != cur->curframe) | |
9242b5f5 AS |
6957 | goto next; |
6958 | for (i = 0; i <= cur->curframe; i++) | |
6959 | if (sl->state.frame[i]->callsite != cur->frame[i]->callsite) | |
6960 | goto next; | |
6961 | clean_verifier_state(env, &sl->state); | |
6962 | next: | |
6963 | sl = sl->next; | |
6964 | } | |
6965 | } | |
6966 | ||
f1174f77 | 6967 | /* Returns true if (rold safe implies rcur safe) */ |
1b688a19 EC |
6968 | static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur, |
6969 | struct idpair *idmap) | |
f1174f77 | 6970 | { |
f4d7e40a AS |
6971 | bool equal; |
6972 | ||
dc503a8a EC |
6973 | if (!(rold->live & REG_LIVE_READ)) |
6974 | /* explored state didn't use this */ | |
6975 | return true; | |
6976 | ||
679c782d | 6977 | equal = memcmp(rold, rcur, offsetof(struct bpf_reg_state, parent)) == 0; |
f4d7e40a AS |
6978 | |
6979 | if (rold->type == PTR_TO_STACK) | |
6980 | /* two stack pointers are equal only if they're pointing to | |
6981 | * the same stack frame, since fp-8 in foo != fp-8 in bar | |
6982 | */ | |
6983 | return equal && rold->frameno == rcur->frameno; | |
6984 | ||
6985 | if (equal) | |
969bf05e AS |
6986 | return true; |
6987 | ||
f1174f77 EC |
6988 | if (rold->type == NOT_INIT) |
6989 | /* explored state can't have used this */ | |
969bf05e | 6990 | return true; |
f1174f77 EC |
6991 | if (rcur->type == NOT_INIT) |
6992 | return false; | |
6993 | switch (rold->type) { | |
6994 | case SCALAR_VALUE: | |
6995 | if (rcur->type == SCALAR_VALUE) { | |
b5dc0163 AS |
6996 | if (!rold->precise && !rcur->precise) |
6997 | return true; | |
f1174f77 EC |
6998 | /* new val must satisfy old val knowledge */ |
6999 | return range_within(rold, rcur) && | |
7000 | tnum_in(rold->var_off, rcur->var_off); | |
7001 | } else { | |
179d1c56 JH |
7002 | /* We're trying to use a pointer in place of a scalar. |
7003 | * Even if the scalar was unbounded, this could lead to | |
7004 | * pointer leaks because scalars are allowed to leak | |
7005 | * while pointers are not. We could make this safe in | |
7006 | * special cases if root is calling us, but it's | |
7007 | * probably not worth the hassle. | |
f1174f77 | 7008 | */ |
179d1c56 | 7009 | return false; |
f1174f77 EC |
7010 | } |
7011 | case PTR_TO_MAP_VALUE: | |
1b688a19 EC |
7012 | /* If the new min/max/var_off satisfy the old ones and |
7013 | * everything else matches, we are OK. | |
d83525ca AS |
7014 | * 'id' is not compared, since it's only used for maps with |
7015 | * bpf_spin_lock inside map element and in such cases if | |
7016 | * the rest of the prog is valid for one map element then | |
7017 | * it's valid for all map elements regardless of the key | |
7018 | * used in bpf_map_lookup() | |
1b688a19 EC |
7019 | */ |
7020 | return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 && | |
7021 | range_within(rold, rcur) && | |
7022 | tnum_in(rold->var_off, rcur->var_off); | |
f1174f77 EC |
7023 | case PTR_TO_MAP_VALUE_OR_NULL: |
7024 | /* a PTR_TO_MAP_VALUE could be safe to use as a | |
7025 | * PTR_TO_MAP_VALUE_OR_NULL into the same map. | |
7026 | * However, if the old PTR_TO_MAP_VALUE_OR_NULL then got NULL- | |
7027 | * checked, doing so could have affected others with the same | |
7028 | * id, and we can't check for that because we lost the id when | |
7029 | * we converted to a PTR_TO_MAP_VALUE. | |
7030 | */ | |
7031 | if (rcur->type != PTR_TO_MAP_VALUE_OR_NULL) | |
7032 | return false; | |
7033 | if (memcmp(rold, rcur, offsetof(struct bpf_reg_state, id))) | |
7034 | return false; | |
7035 | /* Check our ids match any regs they're supposed to */ | |
7036 | return check_ids(rold->id, rcur->id, idmap); | |
de8f3a83 | 7037 | case PTR_TO_PACKET_META: |
f1174f77 | 7038 | case PTR_TO_PACKET: |
de8f3a83 | 7039 | if (rcur->type != rold->type) |
f1174f77 EC |
7040 | return false; |
7041 | /* We must have at least as much range as the old ptr | |
7042 | * did, so that any accesses which were safe before are | |
7043 | * still safe. This is true even if old range < old off, | |
7044 | * since someone could have accessed through (ptr - k), or | |
7045 | * even done ptr -= k in a register, to get a safe access. | |
7046 | */ | |
7047 | if (rold->range > rcur->range) | |
7048 | return false; | |
7049 | /* If the offsets don't match, we can't trust our alignment; | |
7050 | * nor can we be sure that we won't fall out of range. | |
7051 | */ | |
7052 | if (rold->off != rcur->off) | |
7053 | return false; | |
7054 | /* id relations must be preserved */ | |
7055 | if (rold->id && !check_ids(rold->id, rcur->id, idmap)) | |
7056 | return false; | |
7057 | /* new val must satisfy old val knowledge */ | |
7058 | return range_within(rold, rcur) && | |
7059 | tnum_in(rold->var_off, rcur->var_off); | |
7060 | case PTR_TO_CTX: | |
7061 | case CONST_PTR_TO_MAP: | |
f1174f77 | 7062 | case PTR_TO_PACKET_END: |
d58e468b | 7063 | case PTR_TO_FLOW_KEYS: |
c64b7983 JS |
7064 | case PTR_TO_SOCKET: |
7065 | case PTR_TO_SOCKET_OR_NULL: | |
46f8bc92 MKL |
7066 | case PTR_TO_SOCK_COMMON: |
7067 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
655a51e5 MKL |
7068 | case PTR_TO_TCP_SOCK: |
7069 | case PTR_TO_TCP_SOCK_OR_NULL: | |
fada7fdc | 7070 | case PTR_TO_XDP_SOCK: |
f1174f77 EC |
7071 | /* Only valid matches are exact, which memcmp() above |
7072 | * would have accepted | |
7073 | */ | |
7074 | default: | |
7075 | /* Don't know what's going on, just say it's not safe */ | |
7076 | return false; | |
7077 | } | |
969bf05e | 7078 | |
f1174f77 EC |
7079 | /* Shouldn't get here; if we do, say it's not safe */ |
7080 | WARN_ON_ONCE(1); | |
969bf05e AS |
7081 | return false; |
7082 | } | |
7083 | ||
f4d7e40a AS |
7084 | static bool stacksafe(struct bpf_func_state *old, |
7085 | struct bpf_func_state *cur, | |
638f5b90 AS |
7086 | struct idpair *idmap) |
7087 | { | |
7088 | int i, spi; | |
7089 | ||
638f5b90 AS |
7090 | /* walk slots of the explored stack and ignore any additional |
7091 | * slots in the current stack, since explored(safe) state | |
7092 | * didn't use them | |
7093 | */ | |
7094 | for (i = 0; i < old->allocated_stack; i++) { | |
7095 | spi = i / BPF_REG_SIZE; | |
7096 | ||
b233920c AS |
7097 | if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ)) { |
7098 | i += BPF_REG_SIZE - 1; | |
cc2b14d5 | 7099 | /* explored state didn't use this */ |
fd05e57b | 7100 | continue; |
b233920c | 7101 | } |
cc2b14d5 | 7102 | |
638f5b90 AS |
7103 | if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_INVALID) |
7104 | continue; | |
19e2dbb7 AS |
7105 | |
7106 | /* explored stack has more populated slots than current stack | |
7107 | * and these slots were used | |
7108 | */ | |
7109 | if (i >= cur->allocated_stack) | |
7110 | return false; | |
7111 | ||
cc2b14d5 AS |
7112 | /* if old state was safe with misc data in the stack |
7113 | * it will be safe with zero-initialized stack. | |
7114 | * The opposite is not true | |
7115 | */ | |
7116 | if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC && | |
7117 | cur->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_ZERO) | |
7118 | continue; | |
638f5b90 AS |
7119 | if (old->stack[spi].slot_type[i % BPF_REG_SIZE] != |
7120 | cur->stack[spi].slot_type[i % BPF_REG_SIZE]) | |
7121 | /* Ex: old explored (safe) state has STACK_SPILL in | |
7122 | * this stack slot, but current has has STACK_MISC -> | |
7123 | * this verifier states are not equivalent, | |
7124 | * return false to continue verification of this path | |
7125 | */ | |
7126 | return false; | |
7127 | if (i % BPF_REG_SIZE) | |
7128 | continue; | |
7129 | if (old->stack[spi].slot_type[0] != STACK_SPILL) | |
7130 | continue; | |
7131 | if (!regsafe(&old->stack[spi].spilled_ptr, | |
7132 | &cur->stack[spi].spilled_ptr, | |
7133 | idmap)) | |
7134 | /* when explored and current stack slot are both storing | |
7135 | * spilled registers, check that stored pointers types | |
7136 | * are the same as well. | |
7137 | * Ex: explored safe path could have stored | |
7138 | * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8} | |
7139 | * but current path has stored: | |
7140 | * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16} | |
7141 | * such verifier states are not equivalent. | |
7142 | * return false to continue verification of this path | |
7143 | */ | |
7144 | return false; | |
7145 | } | |
7146 | return true; | |
7147 | } | |
7148 | ||
fd978bf7 JS |
7149 | static bool refsafe(struct bpf_func_state *old, struct bpf_func_state *cur) |
7150 | { | |
7151 | if (old->acquired_refs != cur->acquired_refs) | |
7152 | return false; | |
7153 | return !memcmp(old->refs, cur->refs, | |
7154 | sizeof(*old->refs) * old->acquired_refs); | |
7155 | } | |
7156 | ||
f1bca824 AS |
7157 | /* compare two verifier states |
7158 | * | |
7159 | * all states stored in state_list are known to be valid, since | |
7160 | * verifier reached 'bpf_exit' instruction through them | |
7161 | * | |
7162 | * this function is called when verifier exploring different branches of | |
7163 | * execution popped from the state stack. If it sees an old state that has | |
7164 | * more strict register state and more strict stack state then this execution | |
7165 | * branch doesn't need to be explored further, since verifier already | |
7166 | * concluded that more strict state leads to valid finish. | |
7167 | * | |
7168 | * Therefore two states are equivalent if register state is more conservative | |
7169 | * and explored stack state is more conservative than the current one. | |
7170 | * Example: | |
7171 | * explored current | |
7172 | * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC) | |
7173 | * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC) | |
7174 | * | |
7175 | * In other words if current stack state (one being explored) has more | |
7176 | * valid slots than old one that already passed validation, it means | |
7177 | * the verifier can stop exploring and conclude that current state is valid too | |
7178 | * | |
7179 | * Similarly with registers. If explored state has register type as invalid | |
7180 | * whereas register type in current state is meaningful, it means that | |
7181 | * the current state will reach 'bpf_exit' instruction safely | |
7182 | */ | |
f4d7e40a AS |
7183 | static bool func_states_equal(struct bpf_func_state *old, |
7184 | struct bpf_func_state *cur) | |
f1bca824 | 7185 | { |
f1174f77 EC |
7186 | struct idpair *idmap; |
7187 | bool ret = false; | |
f1bca824 AS |
7188 | int i; |
7189 | ||
f1174f77 EC |
7190 | idmap = kcalloc(ID_MAP_SIZE, sizeof(struct idpair), GFP_KERNEL); |
7191 | /* If we failed to allocate the idmap, just say it's not safe */ | |
7192 | if (!idmap) | |
1a0dc1ac | 7193 | return false; |
f1174f77 EC |
7194 | |
7195 | for (i = 0; i < MAX_BPF_REG; i++) { | |
1b688a19 | 7196 | if (!regsafe(&old->regs[i], &cur->regs[i], idmap)) |
f1174f77 | 7197 | goto out_free; |
f1bca824 AS |
7198 | } |
7199 | ||
638f5b90 AS |
7200 | if (!stacksafe(old, cur, idmap)) |
7201 | goto out_free; | |
fd978bf7 JS |
7202 | |
7203 | if (!refsafe(old, cur)) | |
7204 | goto out_free; | |
f1174f77 EC |
7205 | ret = true; |
7206 | out_free: | |
7207 | kfree(idmap); | |
7208 | return ret; | |
f1bca824 AS |
7209 | } |
7210 | ||
f4d7e40a AS |
7211 | static bool states_equal(struct bpf_verifier_env *env, |
7212 | struct bpf_verifier_state *old, | |
7213 | struct bpf_verifier_state *cur) | |
7214 | { | |
7215 | int i; | |
7216 | ||
7217 | if (old->curframe != cur->curframe) | |
7218 | return false; | |
7219 | ||
979d63d5 DB |
7220 | /* Verification state from speculative execution simulation |
7221 | * must never prune a non-speculative execution one. | |
7222 | */ | |
7223 | if (old->speculative && !cur->speculative) | |
7224 | return false; | |
7225 | ||
d83525ca AS |
7226 | if (old->active_spin_lock != cur->active_spin_lock) |
7227 | return false; | |
7228 | ||
f4d7e40a AS |
7229 | /* for states to be equal callsites have to be the same |
7230 | * and all frame states need to be equivalent | |
7231 | */ | |
7232 | for (i = 0; i <= old->curframe; i++) { | |
7233 | if (old->frame[i]->callsite != cur->frame[i]->callsite) | |
7234 | return false; | |
7235 | if (!func_states_equal(old->frame[i], cur->frame[i])) | |
7236 | return false; | |
7237 | } | |
7238 | return true; | |
7239 | } | |
7240 | ||
5327ed3d JW |
7241 | /* Return 0 if no propagation happened. Return negative error code if error |
7242 | * happened. Otherwise, return the propagated bit. | |
7243 | */ | |
55e7f3b5 JW |
7244 | static int propagate_liveness_reg(struct bpf_verifier_env *env, |
7245 | struct bpf_reg_state *reg, | |
7246 | struct bpf_reg_state *parent_reg) | |
7247 | { | |
5327ed3d JW |
7248 | u8 parent_flag = parent_reg->live & REG_LIVE_READ; |
7249 | u8 flag = reg->live & REG_LIVE_READ; | |
55e7f3b5 JW |
7250 | int err; |
7251 | ||
5327ed3d JW |
7252 | /* When comes here, read flags of PARENT_REG or REG could be any of |
7253 | * REG_LIVE_READ64, REG_LIVE_READ32, REG_LIVE_NONE. There is no need | |
7254 | * of propagation if PARENT_REG has strongest REG_LIVE_READ64. | |
7255 | */ | |
7256 | if (parent_flag == REG_LIVE_READ64 || | |
7257 | /* Or if there is no read flag from REG. */ | |
7258 | !flag || | |
7259 | /* Or if the read flag from REG is the same as PARENT_REG. */ | |
7260 | parent_flag == flag) | |
55e7f3b5 JW |
7261 | return 0; |
7262 | ||
5327ed3d | 7263 | err = mark_reg_read(env, reg, parent_reg, flag); |
55e7f3b5 JW |
7264 | if (err) |
7265 | return err; | |
7266 | ||
5327ed3d | 7267 | return flag; |
55e7f3b5 JW |
7268 | } |
7269 | ||
8e9cd9ce | 7270 | /* A write screens off any subsequent reads; but write marks come from the |
f4d7e40a AS |
7271 | * straight-line code between a state and its parent. When we arrive at an |
7272 | * equivalent state (jump target or such) we didn't arrive by the straight-line | |
7273 | * code, so read marks in the state must propagate to the parent regardless | |
7274 | * of the state's write marks. That's what 'parent == state->parent' comparison | |
679c782d | 7275 | * in mark_reg_read() is for. |
8e9cd9ce | 7276 | */ |
f4d7e40a AS |
7277 | static int propagate_liveness(struct bpf_verifier_env *env, |
7278 | const struct bpf_verifier_state *vstate, | |
7279 | struct bpf_verifier_state *vparent) | |
dc503a8a | 7280 | { |
3f8cafa4 | 7281 | struct bpf_reg_state *state_reg, *parent_reg; |
f4d7e40a | 7282 | struct bpf_func_state *state, *parent; |
3f8cafa4 | 7283 | int i, frame, err = 0; |
dc503a8a | 7284 | |
f4d7e40a AS |
7285 | if (vparent->curframe != vstate->curframe) { |
7286 | WARN(1, "propagate_live: parent frame %d current frame %d\n", | |
7287 | vparent->curframe, vstate->curframe); | |
7288 | return -EFAULT; | |
7289 | } | |
dc503a8a EC |
7290 | /* Propagate read liveness of registers... */ |
7291 | BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG); | |
83d16312 | 7292 | for (frame = 0; frame <= vstate->curframe; frame++) { |
3f8cafa4 JW |
7293 | parent = vparent->frame[frame]; |
7294 | state = vstate->frame[frame]; | |
7295 | parent_reg = parent->regs; | |
7296 | state_reg = state->regs; | |
83d16312 JK |
7297 | /* We don't need to worry about FP liveness, it's read-only */ |
7298 | for (i = frame < vstate->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) { | |
55e7f3b5 JW |
7299 | err = propagate_liveness_reg(env, &state_reg[i], |
7300 | &parent_reg[i]); | |
5327ed3d | 7301 | if (err < 0) |
3f8cafa4 | 7302 | return err; |
5327ed3d JW |
7303 | if (err == REG_LIVE_READ64) |
7304 | mark_insn_zext(env, &parent_reg[i]); | |
dc503a8a | 7305 | } |
f4d7e40a | 7306 | |
1b04aee7 | 7307 | /* Propagate stack slots. */ |
f4d7e40a AS |
7308 | for (i = 0; i < state->allocated_stack / BPF_REG_SIZE && |
7309 | i < parent->allocated_stack / BPF_REG_SIZE; i++) { | |
3f8cafa4 JW |
7310 | parent_reg = &parent->stack[i].spilled_ptr; |
7311 | state_reg = &state->stack[i].spilled_ptr; | |
55e7f3b5 JW |
7312 | err = propagate_liveness_reg(env, state_reg, |
7313 | parent_reg); | |
5327ed3d | 7314 | if (err < 0) |
3f8cafa4 | 7315 | return err; |
dc503a8a EC |
7316 | } |
7317 | } | |
5327ed3d | 7318 | return 0; |
dc503a8a EC |
7319 | } |
7320 | ||
a3ce685d AS |
7321 | /* find precise scalars in the previous equivalent state and |
7322 | * propagate them into the current state | |
7323 | */ | |
7324 | static int propagate_precision(struct bpf_verifier_env *env, | |
7325 | const struct bpf_verifier_state *old) | |
7326 | { | |
7327 | struct bpf_reg_state *state_reg; | |
7328 | struct bpf_func_state *state; | |
7329 | int i, err = 0; | |
7330 | ||
7331 | state = old->frame[old->curframe]; | |
7332 | state_reg = state->regs; | |
7333 | for (i = 0; i < BPF_REG_FP; i++, state_reg++) { | |
7334 | if (state_reg->type != SCALAR_VALUE || | |
7335 | !state_reg->precise) | |
7336 | continue; | |
7337 | if (env->log.level & BPF_LOG_LEVEL2) | |
7338 | verbose(env, "propagating r%d\n", i); | |
7339 | err = mark_chain_precision(env, i); | |
7340 | if (err < 0) | |
7341 | return err; | |
7342 | } | |
7343 | ||
7344 | for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) { | |
7345 | if (state->stack[i].slot_type[0] != STACK_SPILL) | |
7346 | continue; | |
7347 | state_reg = &state->stack[i].spilled_ptr; | |
7348 | if (state_reg->type != SCALAR_VALUE || | |
7349 | !state_reg->precise) | |
7350 | continue; | |
7351 | if (env->log.level & BPF_LOG_LEVEL2) | |
7352 | verbose(env, "propagating fp%d\n", | |
7353 | (-i - 1) * BPF_REG_SIZE); | |
7354 | err = mark_chain_precision_stack(env, i); | |
7355 | if (err < 0) | |
7356 | return err; | |
7357 | } | |
7358 | return 0; | |
7359 | } | |
7360 | ||
2589726d AS |
7361 | static bool states_maybe_looping(struct bpf_verifier_state *old, |
7362 | struct bpf_verifier_state *cur) | |
7363 | { | |
7364 | struct bpf_func_state *fold, *fcur; | |
7365 | int i, fr = cur->curframe; | |
7366 | ||
7367 | if (old->curframe != fr) | |
7368 | return false; | |
7369 | ||
7370 | fold = old->frame[fr]; | |
7371 | fcur = cur->frame[fr]; | |
7372 | for (i = 0; i < MAX_BPF_REG; i++) | |
7373 | if (memcmp(&fold->regs[i], &fcur->regs[i], | |
7374 | offsetof(struct bpf_reg_state, parent))) | |
7375 | return false; | |
7376 | return true; | |
7377 | } | |
7378 | ||
7379 | ||
58e2af8b | 7380 | static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) |
f1bca824 | 7381 | { |
58e2af8b | 7382 | struct bpf_verifier_state_list *new_sl; |
9f4686c4 | 7383 | struct bpf_verifier_state_list *sl, **pprev; |
679c782d | 7384 | struct bpf_verifier_state *cur = env->cur_state, *new; |
ceefbc96 | 7385 | int i, j, err, states_cnt = 0; |
10d274e8 | 7386 | bool add_new_state = env->test_state_freq ? true : false; |
f1bca824 | 7387 | |
b5dc0163 | 7388 | cur->last_insn_idx = env->prev_insn_idx; |
a8f500af | 7389 | if (!env->insn_aux_data[insn_idx].prune_point) |
f1bca824 AS |
7390 | /* this 'insn_idx' instruction wasn't marked, so we will not |
7391 | * be doing state search here | |
7392 | */ | |
7393 | return 0; | |
7394 | ||
2589726d AS |
7395 | /* bpf progs typically have pruning point every 4 instructions |
7396 | * http://vger.kernel.org/bpfconf2019.html#session-1 | |
7397 | * Do not add new state for future pruning if the verifier hasn't seen | |
7398 | * at least 2 jumps and at least 8 instructions. | |
7399 | * This heuristics helps decrease 'total_states' and 'peak_states' metric. | |
7400 | * In tests that amounts to up to 50% reduction into total verifier | |
7401 | * memory consumption and 20% verifier time speedup. | |
7402 | */ | |
7403 | if (env->jmps_processed - env->prev_jmps_processed >= 2 && | |
7404 | env->insn_processed - env->prev_insn_processed >= 8) | |
7405 | add_new_state = true; | |
7406 | ||
a8f500af AS |
7407 | pprev = explored_state(env, insn_idx); |
7408 | sl = *pprev; | |
7409 | ||
9242b5f5 AS |
7410 | clean_live_states(env, insn_idx, cur); |
7411 | ||
a8f500af | 7412 | while (sl) { |
dc2a4ebc AS |
7413 | states_cnt++; |
7414 | if (sl->state.insn_idx != insn_idx) | |
7415 | goto next; | |
2589726d AS |
7416 | if (sl->state.branches) { |
7417 | if (states_maybe_looping(&sl->state, cur) && | |
7418 | states_equal(env, &sl->state, cur)) { | |
7419 | verbose_linfo(env, insn_idx, "; "); | |
7420 | verbose(env, "infinite loop detected at insn %d\n", insn_idx); | |
7421 | return -EINVAL; | |
7422 | } | |
7423 | /* if the verifier is processing a loop, avoid adding new state | |
7424 | * too often, since different loop iterations have distinct | |
7425 | * states and may not help future pruning. | |
7426 | * This threshold shouldn't be too low to make sure that | |
7427 | * a loop with large bound will be rejected quickly. | |
7428 | * The most abusive loop will be: | |
7429 | * r1 += 1 | |
7430 | * if r1 < 1000000 goto pc-2 | |
7431 | * 1M insn_procssed limit / 100 == 10k peak states. | |
7432 | * This threshold shouldn't be too high either, since states | |
7433 | * at the end of the loop are likely to be useful in pruning. | |
7434 | */ | |
7435 | if (env->jmps_processed - env->prev_jmps_processed < 20 && | |
7436 | env->insn_processed - env->prev_insn_processed < 100) | |
7437 | add_new_state = false; | |
7438 | goto miss; | |
7439 | } | |
638f5b90 | 7440 | if (states_equal(env, &sl->state, cur)) { |
9f4686c4 | 7441 | sl->hit_cnt++; |
f1bca824 | 7442 | /* reached equivalent register/stack state, |
dc503a8a EC |
7443 | * prune the search. |
7444 | * Registers read by the continuation are read by us. | |
8e9cd9ce EC |
7445 | * If we have any write marks in env->cur_state, they |
7446 | * will prevent corresponding reads in the continuation | |
7447 | * from reaching our parent (an explored_state). Our | |
7448 | * own state will get the read marks recorded, but | |
7449 | * they'll be immediately forgotten as we're pruning | |
7450 | * this state and will pop a new one. | |
f1bca824 | 7451 | */ |
f4d7e40a | 7452 | err = propagate_liveness(env, &sl->state, cur); |
a3ce685d AS |
7453 | |
7454 | /* if previous state reached the exit with precision and | |
7455 | * current state is equivalent to it (except precsion marks) | |
7456 | * the precision needs to be propagated back in | |
7457 | * the current state. | |
7458 | */ | |
7459 | err = err ? : push_jmp_history(env, cur); | |
7460 | err = err ? : propagate_precision(env, &sl->state); | |
f4d7e40a AS |
7461 | if (err) |
7462 | return err; | |
f1bca824 | 7463 | return 1; |
dc503a8a | 7464 | } |
2589726d AS |
7465 | miss: |
7466 | /* when new state is not going to be added do not increase miss count. | |
7467 | * Otherwise several loop iterations will remove the state | |
7468 | * recorded earlier. The goal of these heuristics is to have | |
7469 | * states from some iterations of the loop (some in the beginning | |
7470 | * and some at the end) to help pruning. | |
7471 | */ | |
7472 | if (add_new_state) | |
7473 | sl->miss_cnt++; | |
9f4686c4 AS |
7474 | /* heuristic to determine whether this state is beneficial |
7475 | * to keep checking from state equivalence point of view. | |
7476 | * Higher numbers increase max_states_per_insn and verification time, | |
7477 | * but do not meaningfully decrease insn_processed. | |
7478 | */ | |
7479 | if (sl->miss_cnt > sl->hit_cnt * 3 + 3) { | |
7480 | /* the state is unlikely to be useful. Remove it to | |
7481 | * speed up verification | |
7482 | */ | |
7483 | *pprev = sl->next; | |
7484 | if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE) { | |
2589726d AS |
7485 | u32 br = sl->state.branches; |
7486 | ||
7487 | WARN_ONCE(br, | |
7488 | "BUG live_done but branches_to_explore %d\n", | |
7489 | br); | |
9f4686c4 AS |
7490 | free_verifier_state(&sl->state, false); |
7491 | kfree(sl); | |
7492 | env->peak_states--; | |
7493 | } else { | |
7494 | /* cannot free this state, since parentage chain may | |
7495 | * walk it later. Add it for free_list instead to | |
7496 | * be freed at the end of verification | |
7497 | */ | |
7498 | sl->next = env->free_list; | |
7499 | env->free_list = sl; | |
7500 | } | |
7501 | sl = *pprev; | |
7502 | continue; | |
7503 | } | |
dc2a4ebc | 7504 | next: |
9f4686c4 AS |
7505 | pprev = &sl->next; |
7506 | sl = *pprev; | |
f1bca824 AS |
7507 | } |
7508 | ||
06ee7115 AS |
7509 | if (env->max_states_per_insn < states_cnt) |
7510 | env->max_states_per_insn = states_cnt; | |
7511 | ||
ceefbc96 | 7512 | if (!env->allow_ptr_leaks && states_cnt > BPF_COMPLEXITY_LIMIT_STATES) |
b5dc0163 | 7513 | return push_jmp_history(env, cur); |
ceefbc96 | 7514 | |
2589726d | 7515 | if (!add_new_state) |
b5dc0163 | 7516 | return push_jmp_history(env, cur); |
ceefbc96 | 7517 | |
2589726d AS |
7518 | /* There were no equivalent states, remember the current one. |
7519 | * Technically the current state is not proven to be safe yet, | |
f4d7e40a | 7520 | * but it will either reach outer most bpf_exit (which means it's safe) |
2589726d | 7521 | * or it will be rejected. When there are no loops the verifier won't be |
f4d7e40a | 7522 | * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx) |
2589726d AS |
7523 | * again on the way to bpf_exit. |
7524 | * When looping the sl->state.branches will be > 0 and this state | |
7525 | * will not be considered for equivalence until branches == 0. | |
f1bca824 | 7526 | */ |
638f5b90 | 7527 | new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL); |
f1bca824 AS |
7528 | if (!new_sl) |
7529 | return -ENOMEM; | |
06ee7115 AS |
7530 | env->total_states++; |
7531 | env->peak_states++; | |
2589726d AS |
7532 | env->prev_jmps_processed = env->jmps_processed; |
7533 | env->prev_insn_processed = env->insn_processed; | |
f1bca824 AS |
7534 | |
7535 | /* add new state to the head of linked list */ | |
679c782d EC |
7536 | new = &new_sl->state; |
7537 | err = copy_verifier_state(new, cur); | |
1969db47 | 7538 | if (err) { |
679c782d | 7539 | free_verifier_state(new, false); |
1969db47 AS |
7540 | kfree(new_sl); |
7541 | return err; | |
7542 | } | |
dc2a4ebc | 7543 | new->insn_idx = insn_idx; |
2589726d AS |
7544 | WARN_ONCE(new->branches != 1, |
7545 | "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches, insn_idx); | |
b5dc0163 | 7546 | |
2589726d | 7547 | cur->parent = new; |
b5dc0163 AS |
7548 | cur->first_insn_idx = insn_idx; |
7549 | clear_jmp_history(cur); | |
5d839021 AS |
7550 | new_sl->next = *explored_state(env, insn_idx); |
7551 | *explored_state(env, insn_idx) = new_sl; | |
7640ead9 JK |
7552 | /* connect new state to parentage chain. Current frame needs all |
7553 | * registers connected. Only r6 - r9 of the callers are alive (pushed | |
7554 | * to the stack implicitly by JITs) so in callers' frames connect just | |
7555 | * r6 - r9 as an optimization. Callers will have r1 - r5 connected to | |
7556 | * the state of the call instruction (with WRITTEN set), and r0 comes | |
7557 | * from callee with its full parentage chain, anyway. | |
7558 | */ | |
8e9cd9ce EC |
7559 | /* clear write marks in current state: the writes we did are not writes |
7560 | * our child did, so they don't screen off its reads from us. | |
7561 | * (There are no read marks in current state, because reads always mark | |
7562 | * their parent and current state never has children yet. Only | |
7563 | * explored_states can get read marks.) | |
7564 | */ | |
eea1c227 AS |
7565 | for (j = 0; j <= cur->curframe; j++) { |
7566 | for (i = j < cur->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) | |
7567 | cur->frame[j]->regs[i].parent = &new->frame[j]->regs[i]; | |
7568 | for (i = 0; i < BPF_REG_FP; i++) | |
7569 | cur->frame[j]->regs[i].live = REG_LIVE_NONE; | |
7570 | } | |
f4d7e40a AS |
7571 | |
7572 | /* all stack frames are accessible from callee, clear them all */ | |
7573 | for (j = 0; j <= cur->curframe; j++) { | |
7574 | struct bpf_func_state *frame = cur->frame[j]; | |
679c782d | 7575 | struct bpf_func_state *newframe = new->frame[j]; |
f4d7e40a | 7576 | |
679c782d | 7577 | for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++) { |
cc2b14d5 | 7578 | frame->stack[i].spilled_ptr.live = REG_LIVE_NONE; |
679c782d EC |
7579 | frame->stack[i].spilled_ptr.parent = |
7580 | &newframe->stack[i].spilled_ptr; | |
7581 | } | |
f4d7e40a | 7582 | } |
f1bca824 AS |
7583 | return 0; |
7584 | } | |
7585 | ||
c64b7983 JS |
7586 | /* Return true if it's OK to have the same insn return a different type. */ |
7587 | static bool reg_type_mismatch_ok(enum bpf_reg_type type) | |
7588 | { | |
7589 | switch (type) { | |
7590 | case PTR_TO_CTX: | |
7591 | case PTR_TO_SOCKET: | |
7592 | case PTR_TO_SOCKET_OR_NULL: | |
46f8bc92 MKL |
7593 | case PTR_TO_SOCK_COMMON: |
7594 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
655a51e5 MKL |
7595 | case PTR_TO_TCP_SOCK: |
7596 | case PTR_TO_TCP_SOCK_OR_NULL: | |
fada7fdc | 7597 | case PTR_TO_XDP_SOCK: |
2a02759e | 7598 | case PTR_TO_BTF_ID: |
c64b7983 JS |
7599 | return false; |
7600 | default: | |
7601 | return true; | |
7602 | } | |
7603 | } | |
7604 | ||
7605 | /* If an instruction was previously used with particular pointer types, then we | |
7606 | * need to be careful to avoid cases such as the below, where it may be ok | |
7607 | * for one branch accessing the pointer, but not ok for the other branch: | |
7608 | * | |
7609 | * R1 = sock_ptr | |
7610 | * goto X; | |
7611 | * ... | |
7612 | * R1 = some_other_valid_ptr; | |
7613 | * goto X; | |
7614 | * ... | |
7615 | * R2 = *(u32 *)(R1 + 0); | |
7616 | */ | |
7617 | static bool reg_type_mismatch(enum bpf_reg_type src, enum bpf_reg_type prev) | |
7618 | { | |
7619 | return src != prev && (!reg_type_mismatch_ok(src) || | |
7620 | !reg_type_mismatch_ok(prev)); | |
7621 | } | |
7622 | ||
58e2af8b | 7623 | static int do_check(struct bpf_verifier_env *env) |
17a52670 | 7624 | { |
638f5b90 | 7625 | struct bpf_verifier_state *state; |
17a52670 | 7626 | struct bpf_insn *insns = env->prog->insnsi; |
638f5b90 | 7627 | struct bpf_reg_state *regs; |
06ee7115 | 7628 | int insn_cnt = env->prog->len; |
17a52670 | 7629 | bool do_print_state = false; |
b5dc0163 | 7630 | int prev_insn_idx = -1; |
17a52670 | 7631 | |
d9762e84 MKL |
7632 | env->prev_linfo = NULL; |
7633 | ||
638f5b90 AS |
7634 | state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL); |
7635 | if (!state) | |
7636 | return -ENOMEM; | |
f4d7e40a | 7637 | state->curframe = 0; |
979d63d5 | 7638 | state->speculative = false; |
2589726d | 7639 | state->branches = 1; |
f4d7e40a AS |
7640 | state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL); |
7641 | if (!state->frame[0]) { | |
7642 | kfree(state); | |
7643 | return -ENOMEM; | |
7644 | } | |
7645 | env->cur_state = state; | |
7646 | init_func_state(env, state->frame[0], | |
7647 | BPF_MAIN_FUNC /* callsite */, | |
7648 | 0 /* frameno */, | |
7649 | 0 /* subprogno, zero == main subprog */); | |
c08435ec | 7650 | |
17a52670 AS |
7651 | for (;;) { |
7652 | struct bpf_insn *insn; | |
7653 | u8 class; | |
7654 | int err; | |
7655 | ||
b5dc0163 | 7656 | env->prev_insn_idx = prev_insn_idx; |
c08435ec | 7657 | if (env->insn_idx >= insn_cnt) { |
61bd5218 | 7658 | verbose(env, "invalid insn idx %d insn_cnt %d\n", |
c08435ec | 7659 | env->insn_idx, insn_cnt); |
17a52670 AS |
7660 | return -EFAULT; |
7661 | } | |
7662 | ||
c08435ec | 7663 | insn = &insns[env->insn_idx]; |
17a52670 AS |
7664 | class = BPF_CLASS(insn->code); |
7665 | ||
06ee7115 | 7666 | if (++env->insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) { |
61bd5218 JK |
7667 | verbose(env, |
7668 | "BPF program is too large. Processed %d insn\n", | |
06ee7115 | 7669 | env->insn_processed); |
17a52670 AS |
7670 | return -E2BIG; |
7671 | } | |
7672 | ||
c08435ec | 7673 | err = is_state_visited(env, env->insn_idx); |
f1bca824 AS |
7674 | if (err < 0) |
7675 | return err; | |
7676 | if (err == 1) { | |
7677 | /* found equivalent state, can prune the search */ | |
06ee7115 | 7678 | if (env->log.level & BPF_LOG_LEVEL) { |
f1bca824 | 7679 | if (do_print_state) |
979d63d5 DB |
7680 | verbose(env, "\nfrom %d to %d%s: safe\n", |
7681 | env->prev_insn_idx, env->insn_idx, | |
7682 | env->cur_state->speculative ? | |
7683 | " (speculative execution)" : ""); | |
f1bca824 | 7684 | else |
c08435ec | 7685 | verbose(env, "%d: safe\n", env->insn_idx); |
f1bca824 AS |
7686 | } |
7687 | goto process_bpf_exit; | |
7688 | } | |
7689 | ||
c3494801 AS |
7690 | if (signal_pending(current)) |
7691 | return -EAGAIN; | |
7692 | ||
3c2ce60b DB |
7693 | if (need_resched()) |
7694 | cond_resched(); | |
7695 | ||
06ee7115 AS |
7696 | if (env->log.level & BPF_LOG_LEVEL2 || |
7697 | (env->log.level & BPF_LOG_LEVEL && do_print_state)) { | |
7698 | if (env->log.level & BPF_LOG_LEVEL2) | |
c08435ec | 7699 | verbose(env, "%d:", env->insn_idx); |
c5fc9692 | 7700 | else |
979d63d5 DB |
7701 | verbose(env, "\nfrom %d to %d%s:", |
7702 | env->prev_insn_idx, env->insn_idx, | |
7703 | env->cur_state->speculative ? | |
7704 | " (speculative execution)" : ""); | |
f4d7e40a | 7705 | print_verifier_state(env, state->frame[state->curframe]); |
17a52670 AS |
7706 | do_print_state = false; |
7707 | } | |
7708 | ||
06ee7115 | 7709 | if (env->log.level & BPF_LOG_LEVEL) { |
7105e828 DB |
7710 | const struct bpf_insn_cbs cbs = { |
7711 | .cb_print = verbose, | |
abe08840 | 7712 | .private_data = env, |
7105e828 DB |
7713 | }; |
7714 | ||
c08435ec DB |
7715 | verbose_linfo(env, env->insn_idx, "; "); |
7716 | verbose(env, "%d: ", env->insn_idx); | |
abe08840 | 7717 | print_bpf_insn(&cbs, insn, env->allow_ptr_leaks); |
17a52670 AS |
7718 | } |
7719 | ||
cae1927c | 7720 | if (bpf_prog_is_dev_bound(env->prog->aux)) { |
c08435ec DB |
7721 | err = bpf_prog_offload_verify_insn(env, env->insn_idx, |
7722 | env->prev_insn_idx); | |
cae1927c JK |
7723 | if (err) |
7724 | return err; | |
7725 | } | |
13a27dfc | 7726 | |
638f5b90 | 7727 | regs = cur_regs(env); |
c08435ec | 7728 | env->insn_aux_data[env->insn_idx].seen = true; |
b5dc0163 | 7729 | prev_insn_idx = env->insn_idx; |
fd978bf7 | 7730 | |
17a52670 | 7731 | if (class == BPF_ALU || class == BPF_ALU64) { |
1be7f75d | 7732 | err = check_alu_op(env, insn); |
17a52670 AS |
7733 | if (err) |
7734 | return err; | |
7735 | ||
7736 | } else if (class == BPF_LDX) { | |
3df126f3 | 7737 | enum bpf_reg_type *prev_src_type, src_reg_type; |
9bac3d6d AS |
7738 | |
7739 | /* check for reserved fields is already done */ | |
7740 | ||
17a52670 | 7741 | /* check src operand */ |
dc503a8a | 7742 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
7743 | if (err) |
7744 | return err; | |
7745 | ||
dc503a8a | 7746 | err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); |
17a52670 AS |
7747 | if (err) |
7748 | return err; | |
7749 | ||
725f9dcd AS |
7750 | src_reg_type = regs[insn->src_reg].type; |
7751 | ||
17a52670 AS |
7752 | /* check that memory (src_reg + off) is readable, |
7753 | * the state of dst_reg will be updated by this func | |
7754 | */ | |
c08435ec DB |
7755 | err = check_mem_access(env, env->insn_idx, insn->src_reg, |
7756 | insn->off, BPF_SIZE(insn->code), | |
7757 | BPF_READ, insn->dst_reg, false); | |
17a52670 AS |
7758 | if (err) |
7759 | return err; | |
7760 | ||
c08435ec | 7761 | prev_src_type = &env->insn_aux_data[env->insn_idx].ptr_type; |
3df126f3 JK |
7762 | |
7763 | if (*prev_src_type == NOT_INIT) { | |
9bac3d6d AS |
7764 | /* saw a valid insn |
7765 | * dst_reg = *(u32 *)(src_reg + off) | |
3df126f3 | 7766 | * save type to validate intersecting paths |
9bac3d6d | 7767 | */ |
3df126f3 | 7768 | *prev_src_type = src_reg_type; |
9bac3d6d | 7769 | |
c64b7983 | 7770 | } else if (reg_type_mismatch(src_reg_type, *prev_src_type)) { |
9bac3d6d AS |
7771 | /* ABuser program is trying to use the same insn |
7772 | * dst_reg = *(u32*) (src_reg + off) | |
7773 | * with different pointer types: | |
7774 | * src_reg == ctx in one branch and | |
7775 | * src_reg == stack|map in some other branch. | |
7776 | * Reject it. | |
7777 | */ | |
61bd5218 | 7778 | verbose(env, "same insn cannot be used with different pointers\n"); |
9bac3d6d AS |
7779 | return -EINVAL; |
7780 | } | |
7781 | ||
17a52670 | 7782 | } else if (class == BPF_STX) { |
3df126f3 | 7783 | enum bpf_reg_type *prev_dst_type, dst_reg_type; |
d691f9e8 | 7784 | |
17a52670 | 7785 | if (BPF_MODE(insn->code) == BPF_XADD) { |
c08435ec | 7786 | err = check_xadd(env, env->insn_idx, insn); |
17a52670 AS |
7787 | if (err) |
7788 | return err; | |
c08435ec | 7789 | env->insn_idx++; |
17a52670 AS |
7790 | continue; |
7791 | } | |
7792 | ||
17a52670 | 7793 | /* check src1 operand */ |
dc503a8a | 7794 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
7795 | if (err) |
7796 | return err; | |
7797 | /* check src2 operand */ | |
dc503a8a | 7798 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
7799 | if (err) |
7800 | return err; | |
7801 | ||
d691f9e8 AS |
7802 | dst_reg_type = regs[insn->dst_reg].type; |
7803 | ||
17a52670 | 7804 | /* check that memory (dst_reg + off) is writeable */ |
c08435ec DB |
7805 | err = check_mem_access(env, env->insn_idx, insn->dst_reg, |
7806 | insn->off, BPF_SIZE(insn->code), | |
7807 | BPF_WRITE, insn->src_reg, false); | |
17a52670 AS |
7808 | if (err) |
7809 | return err; | |
7810 | ||
c08435ec | 7811 | prev_dst_type = &env->insn_aux_data[env->insn_idx].ptr_type; |
3df126f3 JK |
7812 | |
7813 | if (*prev_dst_type == NOT_INIT) { | |
7814 | *prev_dst_type = dst_reg_type; | |
c64b7983 | 7815 | } else if (reg_type_mismatch(dst_reg_type, *prev_dst_type)) { |
61bd5218 | 7816 | verbose(env, "same insn cannot be used with different pointers\n"); |
d691f9e8 AS |
7817 | return -EINVAL; |
7818 | } | |
7819 | ||
17a52670 AS |
7820 | } else if (class == BPF_ST) { |
7821 | if (BPF_MODE(insn->code) != BPF_MEM || | |
7822 | insn->src_reg != BPF_REG_0) { | |
61bd5218 | 7823 | verbose(env, "BPF_ST uses reserved fields\n"); |
17a52670 AS |
7824 | return -EINVAL; |
7825 | } | |
7826 | /* check src operand */ | |
dc503a8a | 7827 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
7828 | if (err) |
7829 | return err; | |
7830 | ||
f37a8cb8 | 7831 | if (is_ctx_reg(env, insn->dst_reg)) { |
9d2be44a | 7832 | verbose(env, "BPF_ST stores into R%d %s is not allowed\n", |
2a159c6f DB |
7833 | insn->dst_reg, |
7834 | reg_type_str[reg_state(env, insn->dst_reg)->type]); | |
f37a8cb8 DB |
7835 | return -EACCES; |
7836 | } | |
7837 | ||
17a52670 | 7838 | /* check that memory (dst_reg + off) is writeable */ |
c08435ec DB |
7839 | err = check_mem_access(env, env->insn_idx, insn->dst_reg, |
7840 | insn->off, BPF_SIZE(insn->code), | |
7841 | BPF_WRITE, -1, false); | |
17a52670 AS |
7842 | if (err) |
7843 | return err; | |
7844 | ||
092ed096 | 7845 | } else if (class == BPF_JMP || class == BPF_JMP32) { |
17a52670 AS |
7846 | u8 opcode = BPF_OP(insn->code); |
7847 | ||
2589726d | 7848 | env->jmps_processed++; |
17a52670 AS |
7849 | if (opcode == BPF_CALL) { |
7850 | if (BPF_SRC(insn->code) != BPF_K || | |
7851 | insn->off != 0 || | |
f4d7e40a AS |
7852 | (insn->src_reg != BPF_REG_0 && |
7853 | insn->src_reg != BPF_PSEUDO_CALL) || | |
092ed096 JW |
7854 | insn->dst_reg != BPF_REG_0 || |
7855 | class == BPF_JMP32) { | |
61bd5218 | 7856 | verbose(env, "BPF_CALL uses reserved fields\n"); |
17a52670 AS |
7857 | return -EINVAL; |
7858 | } | |
7859 | ||
d83525ca AS |
7860 | if (env->cur_state->active_spin_lock && |
7861 | (insn->src_reg == BPF_PSEUDO_CALL || | |
7862 | insn->imm != BPF_FUNC_spin_unlock)) { | |
7863 | verbose(env, "function calls are not allowed while holding a lock\n"); | |
7864 | return -EINVAL; | |
7865 | } | |
f4d7e40a | 7866 | if (insn->src_reg == BPF_PSEUDO_CALL) |
c08435ec | 7867 | err = check_func_call(env, insn, &env->insn_idx); |
f4d7e40a | 7868 | else |
c08435ec | 7869 | err = check_helper_call(env, insn->imm, env->insn_idx); |
17a52670 AS |
7870 | if (err) |
7871 | return err; | |
7872 | ||
7873 | } else if (opcode == BPF_JA) { | |
7874 | if (BPF_SRC(insn->code) != BPF_K || | |
7875 | insn->imm != 0 || | |
7876 | insn->src_reg != BPF_REG_0 || | |
092ed096 JW |
7877 | insn->dst_reg != BPF_REG_0 || |
7878 | class == BPF_JMP32) { | |
61bd5218 | 7879 | verbose(env, "BPF_JA uses reserved fields\n"); |
17a52670 AS |
7880 | return -EINVAL; |
7881 | } | |
7882 | ||
c08435ec | 7883 | env->insn_idx += insn->off + 1; |
17a52670 AS |
7884 | continue; |
7885 | ||
7886 | } else if (opcode == BPF_EXIT) { | |
7887 | if (BPF_SRC(insn->code) != BPF_K || | |
7888 | insn->imm != 0 || | |
7889 | insn->src_reg != BPF_REG_0 || | |
092ed096 JW |
7890 | insn->dst_reg != BPF_REG_0 || |
7891 | class == BPF_JMP32) { | |
61bd5218 | 7892 | verbose(env, "BPF_EXIT uses reserved fields\n"); |
17a52670 AS |
7893 | return -EINVAL; |
7894 | } | |
7895 | ||
d83525ca AS |
7896 | if (env->cur_state->active_spin_lock) { |
7897 | verbose(env, "bpf_spin_unlock is missing\n"); | |
7898 | return -EINVAL; | |
7899 | } | |
7900 | ||
f4d7e40a AS |
7901 | if (state->curframe) { |
7902 | /* exit from nested function */ | |
c08435ec | 7903 | err = prepare_func_exit(env, &env->insn_idx); |
f4d7e40a AS |
7904 | if (err) |
7905 | return err; | |
7906 | do_print_state = true; | |
7907 | continue; | |
7908 | } | |
7909 | ||
fd978bf7 JS |
7910 | err = check_reference_leak(env); |
7911 | if (err) | |
7912 | return err; | |
7913 | ||
17a52670 AS |
7914 | /* eBPF calling convetion is such that R0 is used |
7915 | * to return the value from eBPF program. | |
7916 | * Make sure that it's readable at this time | |
7917 | * of bpf_exit, which means that program wrote | |
7918 | * something into it earlier | |
7919 | */ | |
dc503a8a | 7920 | err = check_reg_arg(env, BPF_REG_0, SRC_OP); |
17a52670 AS |
7921 | if (err) |
7922 | return err; | |
7923 | ||
1be7f75d | 7924 | if (is_pointer_value(env, BPF_REG_0)) { |
61bd5218 | 7925 | verbose(env, "R0 leaks addr as return value\n"); |
1be7f75d AS |
7926 | return -EACCES; |
7927 | } | |
7928 | ||
390ee7e2 AS |
7929 | err = check_return_code(env); |
7930 | if (err) | |
7931 | return err; | |
f1bca824 | 7932 | process_bpf_exit: |
2589726d | 7933 | update_branch_counts(env, env->cur_state); |
b5dc0163 | 7934 | err = pop_stack(env, &prev_insn_idx, |
c08435ec | 7935 | &env->insn_idx); |
638f5b90 AS |
7936 | if (err < 0) { |
7937 | if (err != -ENOENT) | |
7938 | return err; | |
17a52670 AS |
7939 | break; |
7940 | } else { | |
7941 | do_print_state = true; | |
7942 | continue; | |
7943 | } | |
7944 | } else { | |
c08435ec | 7945 | err = check_cond_jmp_op(env, insn, &env->insn_idx); |
17a52670 AS |
7946 | if (err) |
7947 | return err; | |
7948 | } | |
7949 | } else if (class == BPF_LD) { | |
7950 | u8 mode = BPF_MODE(insn->code); | |
7951 | ||
7952 | if (mode == BPF_ABS || mode == BPF_IND) { | |
ddd872bc AS |
7953 | err = check_ld_abs(env, insn); |
7954 | if (err) | |
7955 | return err; | |
7956 | ||
17a52670 AS |
7957 | } else if (mode == BPF_IMM) { |
7958 | err = check_ld_imm(env, insn); | |
7959 | if (err) | |
7960 | return err; | |
7961 | ||
c08435ec DB |
7962 | env->insn_idx++; |
7963 | env->insn_aux_data[env->insn_idx].seen = true; | |
17a52670 | 7964 | } else { |
61bd5218 | 7965 | verbose(env, "invalid BPF_LD mode\n"); |
17a52670 AS |
7966 | return -EINVAL; |
7967 | } | |
7968 | } else { | |
61bd5218 | 7969 | verbose(env, "unknown insn class %d\n", class); |
17a52670 AS |
7970 | return -EINVAL; |
7971 | } | |
7972 | ||
c08435ec | 7973 | env->insn_idx++; |
17a52670 AS |
7974 | } |
7975 | ||
9c8105bd | 7976 | env->prog->aux->stack_depth = env->subprog_info[0].stack_depth; |
17a52670 AS |
7977 | return 0; |
7978 | } | |
7979 | ||
56f668df MKL |
7980 | static int check_map_prealloc(struct bpf_map *map) |
7981 | { | |
7982 | return (map->map_type != BPF_MAP_TYPE_HASH && | |
bcc6b1b7 MKL |
7983 | map->map_type != BPF_MAP_TYPE_PERCPU_HASH && |
7984 | map->map_type != BPF_MAP_TYPE_HASH_OF_MAPS) || | |
56f668df MKL |
7985 | !(map->map_flags & BPF_F_NO_PREALLOC); |
7986 | } | |
7987 | ||
d83525ca AS |
7988 | static bool is_tracing_prog_type(enum bpf_prog_type type) |
7989 | { | |
7990 | switch (type) { | |
7991 | case BPF_PROG_TYPE_KPROBE: | |
7992 | case BPF_PROG_TYPE_TRACEPOINT: | |
7993 | case BPF_PROG_TYPE_PERF_EVENT: | |
7994 | case BPF_PROG_TYPE_RAW_TRACEPOINT: | |
7995 | return true; | |
7996 | default: | |
7997 | return false; | |
7998 | } | |
7999 | } | |
8000 | ||
61bd5218 JK |
8001 | static int check_map_prog_compatibility(struct bpf_verifier_env *env, |
8002 | struct bpf_map *map, | |
fdc15d38 AS |
8003 | struct bpf_prog *prog) |
8004 | ||
8005 | { | |
56f668df MKL |
8006 | /* Make sure that BPF_PROG_TYPE_PERF_EVENT programs only use |
8007 | * preallocated hash maps, since doing memory allocation | |
8008 | * in overflow_handler can crash depending on where nmi got | |
8009 | * triggered. | |
8010 | */ | |
8011 | if (prog->type == BPF_PROG_TYPE_PERF_EVENT) { | |
8012 | if (!check_map_prealloc(map)) { | |
61bd5218 | 8013 | verbose(env, "perf_event programs can only use preallocated hash map\n"); |
56f668df MKL |
8014 | return -EINVAL; |
8015 | } | |
8016 | if (map->inner_map_meta && | |
8017 | !check_map_prealloc(map->inner_map_meta)) { | |
61bd5218 | 8018 | verbose(env, "perf_event programs can only use preallocated inner hash map\n"); |
56f668df MKL |
8019 | return -EINVAL; |
8020 | } | |
fdc15d38 | 8021 | } |
a3884572 | 8022 | |
d83525ca AS |
8023 | if ((is_tracing_prog_type(prog->type) || |
8024 | prog->type == BPF_PROG_TYPE_SOCKET_FILTER) && | |
8025 | map_value_has_spin_lock(map)) { | |
8026 | verbose(env, "tracing progs cannot use bpf_spin_lock yet\n"); | |
8027 | return -EINVAL; | |
8028 | } | |
8029 | ||
a3884572 | 8030 | if ((bpf_prog_is_dev_bound(prog->aux) || bpf_map_is_dev_bound(map)) && |
09728266 | 8031 | !bpf_offload_prog_map_match(prog, map)) { |
a3884572 JK |
8032 | verbose(env, "offload device mismatch between prog and map\n"); |
8033 | return -EINVAL; | |
8034 | } | |
8035 | ||
fdc15d38 AS |
8036 | return 0; |
8037 | } | |
8038 | ||
b741f163 RG |
8039 | static bool bpf_map_is_cgroup_storage(struct bpf_map *map) |
8040 | { | |
8041 | return (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE || | |
8042 | map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE); | |
8043 | } | |
8044 | ||
0246e64d AS |
8045 | /* look for pseudo eBPF instructions that access map FDs and |
8046 | * replace them with actual map pointers | |
8047 | */ | |
58e2af8b | 8048 | static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env) |
0246e64d AS |
8049 | { |
8050 | struct bpf_insn *insn = env->prog->insnsi; | |
8051 | int insn_cnt = env->prog->len; | |
fdc15d38 | 8052 | int i, j, err; |
0246e64d | 8053 | |
f1f7714e | 8054 | err = bpf_prog_calc_tag(env->prog); |
aafe6ae9 DB |
8055 | if (err) |
8056 | return err; | |
8057 | ||
0246e64d | 8058 | for (i = 0; i < insn_cnt; i++, insn++) { |
9bac3d6d | 8059 | if (BPF_CLASS(insn->code) == BPF_LDX && |
d691f9e8 | 8060 | (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0)) { |
61bd5218 | 8061 | verbose(env, "BPF_LDX uses reserved fields\n"); |
9bac3d6d AS |
8062 | return -EINVAL; |
8063 | } | |
8064 | ||
d691f9e8 AS |
8065 | if (BPF_CLASS(insn->code) == BPF_STX && |
8066 | ((BPF_MODE(insn->code) != BPF_MEM && | |
8067 | BPF_MODE(insn->code) != BPF_XADD) || insn->imm != 0)) { | |
61bd5218 | 8068 | verbose(env, "BPF_STX uses reserved fields\n"); |
d691f9e8 AS |
8069 | return -EINVAL; |
8070 | } | |
8071 | ||
0246e64d | 8072 | if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) { |
d8eca5bb | 8073 | struct bpf_insn_aux_data *aux; |
0246e64d AS |
8074 | struct bpf_map *map; |
8075 | struct fd f; | |
d8eca5bb | 8076 | u64 addr; |
0246e64d AS |
8077 | |
8078 | if (i == insn_cnt - 1 || insn[1].code != 0 || | |
8079 | insn[1].dst_reg != 0 || insn[1].src_reg != 0 || | |
8080 | insn[1].off != 0) { | |
61bd5218 | 8081 | verbose(env, "invalid bpf_ld_imm64 insn\n"); |
0246e64d AS |
8082 | return -EINVAL; |
8083 | } | |
8084 | ||
d8eca5bb | 8085 | if (insn[0].src_reg == 0) |
0246e64d AS |
8086 | /* valid generic load 64-bit imm */ |
8087 | goto next_insn; | |
8088 | ||
d8eca5bb DB |
8089 | /* In final convert_pseudo_ld_imm64() step, this is |
8090 | * converted into regular 64-bit imm load insn. | |
8091 | */ | |
8092 | if ((insn[0].src_reg != BPF_PSEUDO_MAP_FD && | |
8093 | insn[0].src_reg != BPF_PSEUDO_MAP_VALUE) || | |
8094 | (insn[0].src_reg == BPF_PSEUDO_MAP_FD && | |
8095 | insn[1].imm != 0)) { | |
8096 | verbose(env, | |
8097 | "unrecognized bpf_ld_imm64 insn\n"); | |
0246e64d AS |
8098 | return -EINVAL; |
8099 | } | |
8100 | ||
20182390 | 8101 | f = fdget(insn[0].imm); |
c2101297 | 8102 | map = __bpf_map_get(f); |
0246e64d | 8103 | if (IS_ERR(map)) { |
61bd5218 | 8104 | verbose(env, "fd %d is not pointing to valid bpf_map\n", |
20182390 | 8105 | insn[0].imm); |
0246e64d AS |
8106 | return PTR_ERR(map); |
8107 | } | |
8108 | ||
61bd5218 | 8109 | err = check_map_prog_compatibility(env, map, env->prog); |
fdc15d38 AS |
8110 | if (err) { |
8111 | fdput(f); | |
8112 | return err; | |
8113 | } | |
8114 | ||
d8eca5bb DB |
8115 | aux = &env->insn_aux_data[i]; |
8116 | if (insn->src_reg == BPF_PSEUDO_MAP_FD) { | |
8117 | addr = (unsigned long)map; | |
8118 | } else { | |
8119 | u32 off = insn[1].imm; | |
8120 | ||
8121 | if (off >= BPF_MAX_VAR_OFF) { | |
8122 | verbose(env, "direct value offset of %u is not allowed\n", off); | |
8123 | fdput(f); | |
8124 | return -EINVAL; | |
8125 | } | |
8126 | ||
8127 | if (!map->ops->map_direct_value_addr) { | |
8128 | verbose(env, "no direct value access support for this map type\n"); | |
8129 | fdput(f); | |
8130 | return -EINVAL; | |
8131 | } | |
8132 | ||
8133 | err = map->ops->map_direct_value_addr(map, &addr, off); | |
8134 | if (err) { | |
8135 | verbose(env, "invalid access to map value pointer, value_size=%u off=%u\n", | |
8136 | map->value_size, off); | |
8137 | fdput(f); | |
8138 | return err; | |
8139 | } | |
8140 | ||
8141 | aux->map_off = off; | |
8142 | addr += off; | |
8143 | } | |
8144 | ||
8145 | insn[0].imm = (u32)addr; | |
8146 | insn[1].imm = addr >> 32; | |
0246e64d AS |
8147 | |
8148 | /* check whether we recorded this map already */ | |
d8eca5bb | 8149 | for (j = 0; j < env->used_map_cnt; j++) { |
0246e64d | 8150 | if (env->used_maps[j] == map) { |
d8eca5bb | 8151 | aux->map_index = j; |
0246e64d AS |
8152 | fdput(f); |
8153 | goto next_insn; | |
8154 | } | |
d8eca5bb | 8155 | } |
0246e64d AS |
8156 | |
8157 | if (env->used_map_cnt >= MAX_USED_MAPS) { | |
8158 | fdput(f); | |
8159 | return -E2BIG; | |
8160 | } | |
8161 | ||
0246e64d AS |
8162 | /* hold the map. If the program is rejected by verifier, |
8163 | * the map will be released by release_maps() or it | |
8164 | * will be used by the valid program until it's unloaded | |
ab7f5bf0 | 8165 | * and all maps are released in free_used_maps() |
0246e64d | 8166 | */ |
92117d84 AS |
8167 | map = bpf_map_inc(map, false); |
8168 | if (IS_ERR(map)) { | |
8169 | fdput(f); | |
8170 | return PTR_ERR(map); | |
8171 | } | |
d8eca5bb DB |
8172 | |
8173 | aux->map_index = env->used_map_cnt; | |
92117d84 AS |
8174 | env->used_maps[env->used_map_cnt++] = map; |
8175 | ||
b741f163 | 8176 | if (bpf_map_is_cgroup_storage(map) && |
de9cbbaa | 8177 | bpf_cgroup_storage_assign(env->prog, map)) { |
b741f163 | 8178 | verbose(env, "only one cgroup storage of each type is allowed\n"); |
de9cbbaa RG |
8179 | fdput(f); |
8180 | return -EBUSY; | |
8181 | } | |
8182 | ||
0246e64d AS |
8183 | fdput(f); |
8184 | next_insn: | |
8185 | insn++; | |
8186 | i++; | |
5e581dad DB |
8187 | continue; |
8188 | } | |
8189 | ||
8190 | /* Basic sanity check before we invest more work here. */ | |
8191 | if (!bpf_opcode_in_insntable(insn->code)) { | |
8192 | verbose(env, "unknown opcode %02x\n", insn->code); | |
8193 | return -EINVAL; | |
0246e64d AS |
8194 | } |
8195 | } | |
8196 | ||
8197 | /* now all pseudo BPF_LD_IMM64 instructions load valid | |
8198 | * 'struct bpf_map *' into a register instead of user map_fd. | |
8199 | * These pointers will be used later by verifier to validate map access. | |
8200 | */ | |
8201 | return 0; | |
8202 | } | |
8203 | ||
8204 | /* drop refcnt of maps used by the rejected program */ | |
58e2af8b | 8205 | static void release_maps(struct bpf_verifier_env *env) |
0246e64d | 8206 | { |
8bad74f9 | 8207 | enum bpf_cgroup_storage_type stype; |
0246e64d AS |
8208 | int i; |
8209 | ||
8bad74f9 RG |
8210 | for_each_cgroup_storage_type(stype) { |
8211 | if (!env->prog->aux->cgroup_storage[stype]) | |
8212 | continue; | |
de9cbbaa | 8213 | bpf_cgroup_storage_release(env->prog, |
8bad74f9 RG |
8214 | env->prog->aux->cgroup_storage[stype]); |
8215 | } | |
de9cbbaa | 8216 | |
0246e64d AS |
8217 | for (i = 0; i < env->used_map_cnt; i++) |
8218 | bpf_map_put(env->used_maps[i]); | |
8219 | } | |
8220 | ||
8221 | /* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */ | |
58e2af8b | 8222 | static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env) |
0246e64d AS |
8223 | { |
8224 | struct bpf_insn *insn = env->prog->insnsi; | |
8225 | int insn_cnt = env->prog->len; | |
8226 | int i; | |
8227 | ||
8228 | for (i = 0; i < insn_cnt; i++, insn++) | |
8229 | if (insn->code == (BPF_LD | BPF_IMM | BPF_DW)) | |
8230 | insn->src_reg = 0; | |
8231 | } | |
8232 | ||
8041902d AS |
8233 | /* single env->prog->insni[off] instruction was replaced with the range |
8234 | * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying | |
8235 | * [0, off) and [off, end) to new locations, so the patched range stays zero | |
8236 | */ | |
b325fbca JW |
8237 | static int adjust_insn_aux_data(struct bpf_verifier_env *env, |
8238 | struct bpf_prog *new_prog, u32 off, u32 cnt) | |
8041902d AS |
8239 | { |
8240 | struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data; | |
b325fbca JW |
8241 | struct bpf_insn *insn = new_prog->insnsi; |
8242 | u32 prog_len; | |
c131187d | 8243 | int i; |
8041902d | 8244 | |
b325fbca JW |
8245 | /* aux info at OFF always needs adjustment, no matter fast path |
8246 | * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the | |
8247 | * original insn at old prog. | |
8248 | */ | |
8249 | old_data[off].zext_dst = insn_has_def32(env, insn + off + cnt - 1); | |
8250 | ||
8041902d AS |
8251 | if (cnt == 1) |
8252 | return 0; | |
b325fbca | 8253 | prog_len = new_prog->len; |
fad953ce KC |
8254 | new_data = vzalloc(array_size(prog_len, |
8255 | sizeof(struct bpf_insn_aux_data))); | |
8041902d AS |
8256 | if (!new_data) |
8257 | return -ENOMEM; | |
8258 | memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off); | |
8259 | memcpy(new_data + off + cnt - 1, old_data + off, | |
8260 | sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1)); | |
b325fbca | 8261 | for (i = off; i < off + cnt - 1; i++) { |
c131187d | 8262 | new_data[i].seen = true; |
b325fbca JW |
8263 | new_data[i].zext_dst = insn_has_def32(env, insn + i); |
8264 | } | |
8041902d AS |
8265 | env->insn_aux_data = new_data; |
8266 | vfree(old_data); | |
8267 | return 0; | |
8268 | } | |
8269 | ||
cc8b0b92 AS |
8270 | static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len) |
8271 | { | |
8272 | int i; | |
8273 | ||
8274 | if (len == 1) | |
8275 | return; | |
4cb3d99c JW |
8276 | /* NOTE: fake 'exit' subprog should be updated as well. */ |
8277 | for (i = 0; i <= env->subprog_cnt; i++) { | |
afd59424 | 8278 | if (env->subprog_info[i].start <= off) |
cc8b0b92 | 8279 | continue; |
9c8105bd | 8280 | env->subprog_info[i].start += len - 1; |
cc8b0b92 AS |
8281 | } |
8282 | } | |
8283 | ||
8041902d AS |
8284 | static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off, |
8285 | const struct bpf_insn *patch, u32 len) | |
8286 | { | |
8287 | struct bpf_prog *new_prog; | |
8288 | ||
8289 | new_prog = bpf_patch_insn_single(env->prog, off, patch, len); | |
4f73379e AS |
8290 | if (IS_ERR(new_prog)) { |
8291 | if (PTR_ERR(new_prog) == -ERANGE) | |
8292 | verbose(env, | |
8293 | "insn %d cannot be patched due to 16-bit range\n", | |
8294 | env->insn_aux_data[off].orig_idx); | |
8041902d | 8295 | return NULL; |
4f73379e | 8296 | } |
b325fbca | 8297 | if (adjust_insn_aux_data(env, new_prog, off, len)) |
8041902d | 8298 | return NULL; |
cc8b0b92 | 8299 | adjust_subprog_starts(env, off, len); |
8041902d AS |
8300 | return new_prog; |
8301 | } | |
8302 | ||
52875a04 JK |
8303 | static int adjust_subprog_starts_after_remove(struct bpf_verifier_env *env, |
8304 | u32 off, u32 cnt) | |
8305 | { | |
8306 | int i, j; | |
8307 | ||
8308 | /* find first prog starting at or after off (first to remove) */ | |
8309 | for (i = 0; i < env->subprog_cnt; i++) | |
8310 | if (env->subprog_info[i].start >= off) | |
8311 | break; | |
8312 | /* find first prog starting at or after off + cnt (first to stay) */ | |
8313 | for (j = i; j < env->subprog_cnt; j++) | |
8314 | if (env->subprog_info[j].start >= off + cnt) | |
8315 | break; | |
8316 | /* if j doesn't start exactly at off + cnt, we are just removing | |
8317 | * the front of previous prog | |
8318 | */ | |
8319 | if (env->subprog_info[j].start != off + cnt) | |
8320 | j--; | |
8321 | ||
8322 | if (j > i) { | |
8323 | struct bpf_prog_aux *aux = env->prog->aux; | |
8324 | int move; | |
8325 | ||
8326 | /* move fake 'exit' subprog as well */ | |
8327 | move = env->subprog_cnt + 1 - j; | |
8328 | ||
8329 | memmove(env->subprog_info + i, | |
8330 | env->subprog_info + j, | |
8331 | sizeof(*env->subprog_info) * move); | |
8332 | env->subprog_cnt -= j - i; | |
8333 | ||
8334 | /* remove func_info */ | |
8335 | if (aux->func_info) { | |
8336 | move = aux->func_info_cnt - j; | |
8337 | ||
8338 | memmove(aux->func_info + i, | |
8339 | aux->func_info + j, | |
8340 | sizeof(*aux->func_info) * move); | |
8341 | aux->func_info_cnt -= j - i; | |
8342 | /* func_info->insn_off is set after all code rewrites, | |
8343 | * in adjust_btf_func() - no need to adjust | |
8344 | */ | |
8345 | } | |
8346 | } else { | |
8347 | /* convert i from "first prog to remove" to "first to adjust" */ | |
8348 | if (env->subprog_info[i].start == off) | |
8349 | i++; | |
8350 | } | |
8351 | ||
8352 | /* update fake 'exit' subprog as well */ | |
8353 | for (; i <= env->subprog_cnt; i++) | |
8354 | env->subprog_info[i].start -= cnt; | |
8355 | ||
8356 | return 0; | |
8357 | } | |
8358 | ||
8359 | static int bpf_adj_linfo_after_remove(struct bpf_verifier_env *env, u32 off, | |
8360 | u32 cnt) | |
8361 | { | |
8362 | struct bpf_prog *prog = env->prog; | |
8363 | u32 i, l_off, l_cnt, nr_linfo; | |
8364 | struct bpf_line_info *linfo; | |
8365 | ||
8366 | nr_linfo = prog->aux->nr_linfo; | |
8367 | if (!nr_linfo) | |
8368 | return 0; | |
8369 | ||
8370 | linfo = prog->aux->linfo; | |
8371 | ||
8372 | /* find first line info to remove, count lines to be removed */ | |
8373 | for (i = 0; i < nr_linfo; i++) | |
8374 | if (linfo[i].insn_off >= off) | |
8375 | break; | |
8376 | ||
8377 | l_off = i; | |
8378 | l_cnt = 0; | |
8379 | for (; i < nr_linfo; i++) | |
8380 | if (linfo[i].insn_off < off + cnt) | |
8381 | l_cnt++; | |
8382 | else | |
8383 | break; | |
8384 | ||
8385 | /* First live insn doesn't match first live linfo, it needs to "inherit" | |
8386 | * last removed linfo. prog is already modified, so prog->len == off | |
8387 | * means no live instructions after (tail of the program was removed). | |
8388 | */ | |
8389 | if (prog->len != off && l_cnt && | |
8390 | (i == nr_linfo || linfo[i].insn_off != off + cnt)) { | |
8391 | l_cnt--; | |
8392 | linfo[--i].insn_off = off + cnt; | |
8393 | } | |
8394 | ||
8395 | /* remove the line info which refer to the removed instructions */ | |
8396 | if (l_cnt) { | |
8397 | memmove(linfo + l_off, linfo + i, | |
8398 | sizeof(*linfo) * (nr_linfo - i)); | |
8399 | ||
8400 | prog->aux->nr_linfo -= l_cnt; | |
8401 | nr_linfo = prog->aux->nr_linfo; | |
8402 | } | |
8403 | ||
8404 | /* pull all linfo[i].insn_off >= off + cnt in by cnt */ | |
8405 | for (i = l_off; i < nr_linfo; i++) | |
8406 | linfo[i].insn_off -= cnt; | |
8407 | ||
8408 | /* fix up all subprogs (incl. 'exit') which start >= off */ | |
8409 | for (i = 0; i <= env->subprog_cnt; i++) | |
8410 | if (env->subprog_info[i].linfo_idx > l_off) { | |
8411 | /* program may have started in the removed region but | |
8412 | * may not be fully removed | |
8413 | */ | |
8414 | if (env->subprog_info[i].linfo_idx >= l_off + l_cnt) | |
8415 | env->subprog_info[i].linfo_idx -= l_cnt; | |
8416 | else | |
8417 | env->subprog_info[i].linfo_idx = l_off; | |
8418 | } | |
8419 | ||
8420 | return 0; | |
8421 | } | |
8422 | ||
8423 | static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt) | |
8424 | { | |
8425 | struct bpf_insn_aux_data *aux_data = env->insn_aux_data; | |
8426 | unsigned int orig_prog_len = env->prog->len; | |
8427 | int err; | |
8428 | ||
08ca90af JK |
8429 | if (bpf_prog_is_dev_bound(env->prog->aux)) |
8430 | bpf_prog_offload_remove_insns(env, off, cnt); | |
8431 | ||
52875a04 JK |
8432 | err = bpf_remove_insns(env->prog, off, cnt); |
8433 | if (err) | |
8434 | return err; | |
8435 | ||
8436 | err = adjust_subprog_starts_after_remove(env, off, cnt); | |
8437 | if (err) | |
8438 | return err; | |
8439 | ||
8440 | err = bpf_adj_linfo_after_remove(env, off, cnt); | |
8441 | if (err) | |
8442 | return err; | |
8443 | ||
8444 | memmove(aux_data + off, aux_data + off + cnt, | |
8445 | sizeof(*aux_data) * (orig_prog_len - off - cnt)); | |
8446 | ||
8447 | return 0; | |
8448 | } | |
8449 | ||
2a5418a1 DB |
8450 | /* The verifier does more data flow analysis than llvm and will not |
8451 | * explore branches that are dead at run time. Malicious programs can | |
8452 | * have dead code too. Therefore replace all dead at-run-time code | |
8453 | * with 'ja -1'. | |
8454 | * | |
8455 | * Just nops are not optimal, e.g. if they would sit at the end of the | |
8456 | * program and through another bug we would manage to jump there, then | |
8457 | * we'd execute beyond program memory otherwise. Returning exception | |
8458 | * code also wouldn't work since we can have subprogs where the dead | |
8459 | * code could be located. | |
c131187d AS |
8460 | */ |
8461 | static void sanitize_dead_code(struct bpf_verifier_env *env) | |
8462 | { | |
8463 | struct bpf_insn_aux_data *aux_data = env->insn_aux_data; | |
2a5418a1 | 8464 | struct bpf_insn trap = BPF_JMP_IMM(BPF_JA, 0, 0, -1); |
c131187d AS |
8465 | struct bpf_insn *insn = env->prog->insnsi; |
8466 | const int insn_cnt = env->prog->len; | |
8467 | int i; | |
8468 | ||
8469 | for (i = 0; i < insn_cnt; i++) { | |
8470 | if (aux_data[i].seen) | |
8471 | continue; | |
2a5418a1 | 8472 | memcpy(insn + i, &trap, sizeof(trap)); |
c131187d AS |
8473 | } |
8474 | } | |
8475 | ||
e2ae4ca2 JK |
8476 | static bool insn_is_cond_jump(u8 code) |
8477 | { | |
8478 | u8 op; | |
8479 | ||
092ed096 JW |
8480 | if (BPF_CLASS(code) == BPF_JMP32) |
8481 | return true; | |
8482 | ||
e2ae4ca2 JK |
8483 | if (BPF_CLASS(code) != BPF_JMP) |
8484 | return false; | |
8485 | ||
8486 | op = BPF_OP(code); | |
8487 | return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL; | |
8488 | } | |
8489 | ||
8490 | static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env) | |
8491 | { | |
8492 | struct bpf_insn_aux_data *aux_data = env->insn_aux_data; | |
8493 | struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0); | |
8494 | struct bpf_insn *insn = env->prog->insnsi; | |
8495 | const int insn_cnt = env->prog->len; | |
8496 | int i; | |
8497 | ||
8498 | for (i = 0; i < insn_cnt; i++, insn++) { | |
8499 | if (!insn_is_cond_jump(insn->code)) | |
8500 | continue; | |
8501 | ||
8502 | if (!aux_data[i + 1].seen) | |
8503 | ja.off = insn->off; | |
8504 | else if (!aux_data[i + 1 + insn->off].seen) | |
8505 | ja.off = 0; | |
8506 | else | |
8507 | continue; | |
8508 | ||
08ca90af JK |
8509 | if (bpf_prog_is_dev_bound(env->prog->aux)) |
8510 | bpf_prog_offload_replace_insn(env, i, &ja); | |
8511 | ||
e2ae4ca2 JK |
8512 | memcpy(insn, &ja, sizeof(ja)); |
8513 | } | |
8514 | } | |
8515 | ||
52875a04 JK |
8516 | static int opt_remove_dead_code(struct bpf_verifier_env *env) |
8517 | { | |
8518 | struct bpf_insn_aux_data *aux_data = env->insn_aux_data; | |
8519 | int insn_cnt = env->prog->len; | |
8520 | int i, err; | |
8521 | ||
8522 | for (i = 0; i < insn_cnt; i++) { | |
8523 | int j; | |
8524 | ||
8525 | j = 0; | |
8526 | while (i + j < insn_cnt && !aux_data[i + j].seen) | |
8527 | j++; | |
8528 | if (!j) | |
8529 | continue; | |
8530 | ||
8531 | err = verifier_remove_insns(env, i, j); | |
8532 | if (err) | |
8533 | return err; | |
8534 | insn_cnt = env->prog->len; | |
8535 | } | |
8536 | ||
8537 | return 0; | |
8538 | } | |
8539 | ||
a1b14abc JK |
8540 | static int opt_remove_nops(struct bpf_verifier_env *env) |
8541 | { | |
8542 | const struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0); | |
8543 | struct bpf_insn *insn = env->prog->insnsi; | |
8544 | int insn_cnt = env->prog->len; | |
8545 | int i, err; | |
8546 | ||
8547 | for (i = 0; i < insn_cnt; i++) { | |
8548 | if (memcmp(&insn[i], &ja, sizeof(ja))) | |
8549 | continue; | |
8550 | ||
8551 | err = verifier_remove_insns(env, i, 1); | |
8552 | if (err) | |
8553 | return err; | |
8554 | insn_cnt--; | |
8555 | i--; | |
8556 | } | |
8557 | ||
8558 | return 0; | |
8559 | } | |
8560 | ||
d6c2308c JW |
8561 | static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env, |
8562 | const union bpf_attr *attr) | |
a4b1d3c1 | 8563 | { |
d6c2308c | 8564 | struct bpf_insn *patch, zext_patch[2], rnd_hi32_patch[4]; |
a4b1d3c1 | 8565 | struct bpf_insn_aux_data *aux = env->insn_aux_data; |
d6c2308c | 8566 | int i, patch_len, delta = 0, len = env->prog->len; |
a4b1d3c1 | 8567 | struct bpf_insn *insns = env->prog->insnsi; |
a4b1d3c1 | 8568 | struct bpf_prog *new_prog; |
d6c2308c | 8569 | bool rnd_hi32; |
a4b1d3c1 | 8570 | |
d6c2308c | 8571 | rnd_hi32 = attr->prog_flags & BPF_F_TEST_RND_HI32; |
a4b1d3c1 | 8572 | zext_patch[1] = BPF_ZEXT_REG(0); |
d6c2308c JW |
8573 | rnd_hi32_patch[1] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, 0); |
8574 | rnd_hi32_patch[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); | |
8575 | rnd_hi32_patch[3] = BPF_ALU64_REG(BPF_OR, 0, BPF_REG_AX); | |
a4b1d3c1 JW |
8576 | for (i = 0; i < len; i++) { |
8577 | int adj_idx = i + delta; | |
8578 | struct bpf_insn insn; | |
8579 | ||
d6c2308c JW |
8580 | insn = insns[adj_idx]; |
8581 | if (!aux[adj_idx].zext_dst) { | |
8582 | u8 code, class; | |
8583 | u32 imm_rnd; | |
8584 | ||
8585 | if (!rnd_hi32) | |
8586 | continue; | |
8587 | ||
8588 | code = insn.code; | |
8589 | class = BPF_CLASS(code); | |
8590 | if (insn_no_def(&insn)) | |
8591 | continue; | |
8592 | ||
8593 | /* NOTE: arg "reg" (the fourth one) is only used for | |
8594 | * BPF_STX which has been ruled out in above | |
8595 | * check, it is safe to pass NULL here. | |
8596 | */ | |
8597 | if (is_reg64(env, &insn, insn.dst_reg, NULL, DST_OP)) { | |
8598 | if (class == BPF_LD && | |
8599 | BPF_MODE(code) == BPF_IMM) | |
8600 | i++; | |
8601 | continue; | |
8602 | } | |
8603 | ||
8604 | /* ctx load could be transformed into wider load. */ | |
8605 | if (class == BPF_LDX && | |
8606 | aux[adj_idx].ptr_type == PTR_TO_CTX) | |
8607 | continue; | |
8608 | ||
8609 | imm_rnd = get_random_int(); | |
8610 | rnd_hi32_patch[0] = insn; | |
8611 | rnd_hi32_patch[1].imm = imm_rnd; | |
8612 | rnd_hi32_patch[3].dst_reg = insn.dst_reg; | |
8613 | patch = rnd_hi32_patch; | |
8614 | patch_len = 4; | |
8615 | goto apply_patch_buffer; | |
8616 | } | |
8617 | ||
8618 | if (!bpf_jit_needs_zext()) | |
a4b1d3c1 JW |
8619 | continue; |
8620 | ||
a4b1d3c1 JW |
8621 | zext_patch[0] = insn; |
8622 | zext_patch[1].dst_reg = insn.dst_reg; | |
8623 | zext_patch[1].src_reg = insn.dst_reg; | |
d6c2308c JW |
8624 | patch = zext_patch; |
8625 | patch_len = 2; | |
8626 | apply_patch_buffer: | |
8627 | new_prog = bpf_patch_insn_data(env, adj_idx, patch, patch_len); | |
a4b1d3c1 JW |
8628 | if (!new_prog) |
8629 | return -ENOMEM; | |
8630 | env->prog = new_prog; | |
8631 | insns = new_prog->insnsi; | |
8632 | aux = env->insn_aux_data; | |
d6c2308c | 8633 | delta += patch_len - 1; |
a4b1d3c1 JW |
8634 | } |
8635 | ||
8636 | return 0; | |
8637 | } | |
8638 | ||
c64b7983 JS |
8639 | /* convert load instructions that access fields of a context type into a |
8640 | * sequence of instructions that access fields of the underlying structure: | |
8641 | * struct __sk_buff -> struct sk_buff | |
8642 | * struct bpf_sock_ops -> struct sock | |
9bac3d6d | 8643 | */ |
58e2af8b | 8644 | static int convert_ctx_accesses(struct bpf_verifier_env *env) |
9bac3d6d | 8645 | { |
00176a34 | 8646 | const struct bpf_verifier_ops *ops = env->ops; |
f96da094 | 8647 | int i, cnt, size, ctx_field_size, delta = 0; |
3df126f3 | 8648 | const int insn_cnt = env->prog->len; |
36bbef52 | 8649 | struct bpf_insn insn_buf[16], *insn; |
46f53a65 | 8650 | u32 target_size, size_default, off; |
9bac3d6d | 8651 | struct bpf_prog *new_prog; |
d691f9e8 | 8652 | enum bpf_access_type type; |
f96da094 | 8653 | bool is_narrower_load; |
9bac3d6d | 8654 | |
b09928b9 DB |
8655 | if (ops->gen_prologue || env->seen_direct_write) { |
8656 | if (!ops->gen_prologue) { | |
8657 | verbose(env, "bpf verifier is misconfigured\n"); | |
8658 | return -EINVAL; | |
8659 | } | |
36bbef52 DB |
8660 | cnt = ops->gen_prologue(insn_buf, env->seen_direct_write, |
8661 | env->prog); | |
8662 | if (cnt >= ARRAY_SIZE(insn_buf)) { | |
61bd5218 | 8663 | verbose(env, "bpf verifier is misconfigured\n"); |
36bbef52 DB |
8664 | return -EINVAL; |
8665 | } else if (cnt) { | |
8041902d | 8666 | new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt); |
36bbef52 DB |
8667 | if (!new_prog) |
8668 | return -ENOMEM; | |
8041902d | 8669 | |
36bbef52 | 8670 | env->prog = new_prog; |
3df126f3 | 8671 | delta += cnt - 1; |
36bbef52 DB |
8672 | } |
8673 | } | |
8674 | ||
c64b7983 | 8675 | if (bpf_prog_is_dev_bound(env->prog->aux)) |
9bac3d6d AS |
8676 | return 0; |
8677 | ||
3df126f3 | 8678 | insn = env->prog->insnsi + delta; |
36bbef52 | 8679 | |
9bac3d6d | 8680 | for (i = 0; i < insn_cnt; i++, insn++) { |
c64b7983 JS |
8681 | bpf_convert_ctx_access_t convert_ctx_access; |
8682 | ||
62c7989b DB |
8683 | if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) || |
8684 | insn->code == (BPF_LDX | BPF_MEM | BPF_H) || | |
8685 | insn->code == (BPF_LDX | BPF_MEM | BPF_W) || | |
ea2e7ce5 | 8686 | insn->code == (BPF_LDX | BPF_MEM | BPF_DW)) |
d691f9e8 | 8687 | type = BPF_READ; |
62c7989b DB |
8688 | else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) || |
8689 | insn->code == (BPF_STX | BPF_MEM | BPF_H) || | |
8690 | insn->code == (BPF_STX | BPF_MEM | BPF_W) || | |
ea2e7ce5 | 8691 | insn->code == (BPF_STX | BPF_MEM | BPF_DW)) |
d691f9e8 AS |
8692 | type = BPF_WRITE; |
8693 | else | |
9bac3d6d AS |
8694 | continue; |
8695 | ||
af86ca4e AS |
8696 | if (type == BPF_WRITE && |
8697 | env->insn_aux_data[i + delta].sanitize_stack_off) { | |
8698 | struct bpf_insn patch[] = { | |
8699 | /* Sanitize suspicious stack slot with zero. | |
8700 | * There are no memory dependencies for this store, | |
8701 | * since it's only using frame pointer and immediate | |
8702 | * constant of zero | |
8703 | */ | |
8704 | BPF_ST_MEM(BPF_DW, BPF_REG_FP, | |
8705 | env->insn_aux_data[i + delta].sanitize_stack_off, | |
8706 | 0), | |
8707 | /* the original STX instruction will immediately | |
8708 | * overwrite the same stack slot with appropriate value | |
8709 | */ | |
8710 | *insn, | |
8711 | }; | |
8712 | ||
8713 | cnt = ARRAY_SIZE(patch); | |
8714 | new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt); | |
8715 | if (!new_prog) | |
8716 | return -ENOMEM; | |
8717 | ||
8718 | delta += cnt - 1; | |
8719 | env->prog = new_prog; | |
8720 | insn = new_prog->insnsi + i + delta; | |
8721 | continue; | |
8722 | } | |
8723 | ||
c64b7983 JS |
8724 | switch (env->insn_aux_data[i + delta].ptr_type) { |
8725 | case PTR_TO_CTX: | |
8726 | if (!ops->convert_ctx_access) | |
8727 | continue; | |
8728 | convert_ctx_access = ops->convert_ctx_access; | |
8729 | break; | |
8730 | case PTR_TO_SOCKET: | |
46f8bc92 | 8731 | case PTR_TO_SOCK_COMMON: |
c64b7983 JS |
8732 | convert_ctx_access = bpf_sock_convert_ctx_access; |
8733 | break; | |
655a51e5 MKL |
8734 | case PTR_TO_TCP_SOCK: |
8735 | convert_ctx_access = bpf_tcp_sock_convert_ctx_access; | |
8736 | break; | |
fada7fdc JL |
8737 | case PTR_TO_XDP_SOCK: |
8738 | convert_ctx_access = bpf_xdp_sock_convert_ctx_access; | |
8739 | break; | |
2a02759e AS |
8740 | case PTR_TO_BTF_ID: |
8741 | if (type == BPF_WRITE) { | |
8742 | verbose(env, "Writes through BTF pointers are not allowed\n"); | |
8743 | return -EINVAL; | |
8744 | } | |
8745 | insn->code = BPF_LDX | BPF_PROBE_MEM | BPF_SIZE((insn)->code); | |
3dec541b | 8746 | env->prog->aux->num_exentries++; |
2a02759e | 8747 | continue; |
c64b7983 | 8748 | default: |
9bac3d6d | 8749 | continue; |
c64b7983 | 8750 | } |
9bac3d6d | 8751 | |
31fd8581 | 8752 | ctx_field_size = env->insn_aux_data[i + delta].ctx_field_size; |
f96da094 | 8753 | size = BPF_LDST_BYTES(insn); |
31fd8581 YS |
8754 | |
8755 | /* If the read access is a narrower load of the field, | |
8756 | * convert to a 4/8-byte load, to minimum program type specific | |
8757 | * convert_ctx_access changes. If conversion is successful, | |
8758 | * we will apply proper mask to the result. | |
8759 | */ | |
f96da094 | 8760 | is_narrower_load = size < ctx_field_size; |
46f53a65 AI |
8761 | size_default = bpf_ctx_off_adjust_machine(ctx_field_size); |
8762 | off = insn->off; | |
31fd8581 | 8763 | if (is_narrower_load) { |
f96da094 DB |
8764 | u8 size_code; |
8765 | ||
8766 | if (type == BPF_WRITE) { | |
61bd5218 | 8767 | verbose(env, "bpf verifier narrow ctx access misconfigured\n"); |
f96da094 DB |
8768 | return -EINVAL; |
8769 | } | |
31fd8581 | 8770 | |
f96da094 | 8771 | size_code = BPF_H; |
31fd8581 YS |
8772 | if (ctx_field_size == 4) |
8773 | size_code = BPF_W; | |
8774 | else if (ctx_field_size == 8) | |
8775 | size_code = BPF_DW; | |
f96da094 | 8776 | |
bc23105c | 8777 | insn->off = off & ~(size_default - 1); |
31fd8581 YS |
8778 | insn->code = BPF_LDX | BPF_MEM | size_code; |
8779 | } | |
f96da094 DB |
8780 | |
8781 | target_size = 0; | |
c64b7983 JS |
8782 | cnt = convert_ctx_access(type, insn, insn_buf, env->prog, |
8783 | &target_size); | |
f96da094 DB |
8784 | if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) || |
8785 | (ctx_field_size && !target_size)) { | |
61bd5218 | 8786 | verbose(env, "bpf verifier is misconfigured\n"); |
9bac3d6d AS |
8787 | return -EINVAL; |
8788 | } | |
f96da094 DB |
8789 | |
8790 | if (is_narrower_load && size < target_size) { | |
d895a0f1 IL |
8791 | u8 shift = bpf_ctx_narrow_access_offset( |
8792 | off, size, size_default) * 8; | |
46f53a65 AI |
8793 | if (ctx_field_size <= 4) { |
8794 | if (shift) | |
8795 | insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH, | |
8796 | insn->dst_reg, | |
8797 | shift); | |
31fd8581 | 8798 | insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg, |
f96da094 | 8799 | (1 << size * 8) - 1); |
46f53a65 AI |
8800 | } else { |
8801 | if (shift) | |
8802 | insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH, | |
8803 | insn->dst_reg, | |
8804 | shift); | |
31fd8581 | 8805 | insn_buf[cnt++] = BPF_ALU64_IMM(BPF_AND, insn->dst_reg, |
e2f7fc0a | 8806 | (1ULL << size * 8) - 1); |
46f53a65 | 8807 | } |
31fd8581 | 8808 | } |
9bac3d6d | 8809 | |
8041902d | 8810 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); |
9bac3d6d AS |
8811 | if (!new_prog) |
8812 | return -ENOMEM; | |
8813 | ||
3df126f3 | 8814 | delta += cnt - 1; |
9bac3d6d AS |
8815 | |
8816 | /* keep walking new program and skip insns we just inserted */ | |
8817 | env->prog = new_prog; | |
3df126f3 | 8818 | insn = new_prog->insnsi + i + delta; |
9bac3d6d AS |
8819 | } |
8820 | ||
8821 | return 0; | |
8822 | } | |
8823 | ||
1c2a088a AS |
8824 | static int jit_subprogs(struct bpf_verifier_env *env) |
8825 | { | |
8826 | struct bpf_prog *prog = env->prog, **func, *tmp; | |
8827 | int i, j, subprog_start, subprog_end = 0, len, subprog; | |
7105e828 | 8828 | struct bpf_insn *insn; |
1c2a088a | 8829 | void *old_bpf_func; |
c454a46b | 8830 | int err; |
1c2a088a | 8831 | |
f910cefa | 8832 | if (env->subprog_cnt <= 1) |
1c2a088a AS |
8833 | return 0; |
8834 | ||
7105e828 | 8835 | for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { |
1c2a088a AS |
8836 | if (insn->code != (BPF_JMP | BPF_CALL) || |
8837 | insn->src_reg != BPF_PSEUDO_CALL) | |
8838 | continue; | |
c7a89784 DB |
8839 | /* Upon error here we cannot fall back to interpreter but |
8840 | * need a hard reject of the program. Thus -EFAULT is | |
8841 | * propagated in any case. | |
8842 | */ | |
1c2a088a AS |
8843 | subprog = find_subprog(env, i + insn->imm + 1); |
8844 | if (subprog < 0) { | |
8845 | WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", | |
8846 | i + insn->imm + 1); | |
8847 | return -EFAULT; | |
8848 | } | |
8849 | /* temporarily remember subprog id inside insn instead of | |
8850 | * aux_data, since next loop will split up all insns into funcs | |
8851 | */ | |
f910cefa | 8852 | insn->off = subprog; |
1c2a088a AS |
8853 | /* remember original imm in case JIT fails and fallback |
8854 | * to interpreter will be needed | |
8855 | */ | |
8856 | env->insn_aux_data[i].call_imm = insn->imm; | |
8857 | /* point imm to __bpf_call_base+1 from JITs point of view */ | |
8858 | insn->imm = 1; | |
8859 | } | |
8860 | ||
c454a46b MKL |
8861 | err = bpf_prog_alloc_jited_linfo(prog); |
8862 | if (err) | |
8863 | goto out_undo_insn; | |
8864 | ||
8865 | err = -ENOMEM; | |
6396bb22 | 8866 | func = kcalloc(env->subprog_cnt, sizeof(prog), GFP_KERNEL); |
1c2a088a | 8867 | if (!func) |
c7a89784 | 8868 | goto out_undo_insn; |
1c2a088a | 8869 | |
f910cefa | 8870 | for (i = 0; i < env->subprog_cnt; i++) { |
1c2a088a | 8871 | subprog_start = subprog_end; |
4cb3d99c | 8872 | subprog_end = env->subprog_info[i + 1].start; |
1c2a088a AS |
8873 | |
8874 | len = subprog_end - subprog_start; | |
492ecee8 AS |
8875 | /* BPF_PROG_RUN doesn't call subprogs directly, |
8876 | * hence main prog stats include the runtime of subprogs. | |
8877 | * subprogs don't have IDs and not reachable via prog_get_next_id | |
8878 | * func[i]->aux->stats will never be accessed and stays NULL | |
8879 | */ | |
8880 | func[i] = bpf_prog_alloc_no_stats(bpf_prog_size(len), GFP_USER); | |
1c2a088a AS |
8881 | if (!func[i]) |
8882 | goto out_free; | |
8883 | memcpy(func[i]->insnsi, &prog->insnsi[subprog_start], | |
8884 | len * sizeof(struct bpf_insn)); | |
4f74d809 | 8885 | func[i]->type = prog->type; |
1c2a088a | 8886 | func[i]->len = len; |
4f74d809 DB |
8887 | if (bpf_prog_calc_tag(func[i])) |
8888 | goto out_free; | |
1c2a088a | 8889 | func[i]->is_func = 1; |
ba64e7d8 YS |
8890 | func[i]->aux->func_idx = i; |
8891 | /* the btf and func_info will be freed only at prog->aux */ | |
8892 | func[i]->aux->btf = prog->aux->btf; | |
8893 | func[i]->aux->func_info = prog->aux->func_info; | |
8894 | ||
1c2a088a AS |
8895 | /* Use bpf_prog_F_tag to indicate functions in stack traces. |
8896 | * Long term would need debug info to populate names | |
8897 | */ | |
8898 | func[i]->aux->name[0] = 'F'; | |
9c8105bd | 8899 | func[i]->aux->stack_depth = env->subprog_info[i].stack_depth; |
1c2a088a | 8900 | func[i]->jit_requested = 1; |
c454a46b MKL |
8901 | func[i]->aux->linfo = prog->aux->linfo; |
8902 | func[i]->aux->nr_linfo = prog->aux->nr_linfo; | |
8903 | func[i]->aux->jited_linfo = prog->aux->jited_linfo; | |
8904 | func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx; | |
1c2a088a AS |
8905 | func[i] = bpf_int_jit_compile(func[i]); |
8906 | if (!func[i]->jited) { | |
8907 | err = -ENOTSUPP; | |
8908 | goto out_free; | |
8909 | } | |
8910 | cond_resched(); | |
8911 | } | |
8912 | /* at this point all bpf functions were successfully JITed | |
8913 | * now populate all bpf_calls with correct addresses and | |
8914 | * run last pass of JIT | |
8915 | */ | |
f910cefa | 8916 | for (i = 0; i < env->subprog_cnt; i++) { |
1c2a088a AS |
8917 | insn = func[i]->insnsi; |
8918 | for (j = 0; j < func[i]->len; j++, insn++) { | |
8919 | if (insn->code != (BPF_JMP | BPF_CALL) || | |
8920 | insn->src_reg != BPF_PSEUDO_CALL) | |
8921 | continue; | |
8922 | subprog = insn->off; | |
0d306c31 PB |
8923 | insn->imm = BPF_CAST_CALL(func[subprog]->bpf_func) - |
8924 | __bpf_call_base; | |
1c2a088a | 8925 | } |
2162fed4 SD |
8926 | |
8927 | /* we use the aux data to keep a list of the start addresses | |
8928 | * of the JITed images for each function in the program | |
8929 | * | |
8930 | * for some architectures, such as powerpc64, the imm field | |
8931 | * might not be large enough to hold the offset of the start | |
8932 | * address of the callee's JITed image from __bpf_call_base | |
8933 | * | |
8934 | * in such cases, we can lookup the start address of a callee | |
8935 | * by using its subprog id, available from the off field of | |
8936 | * the call instruction, as an index for this list | |
8937 | */ | |
8938 | func[i]->aux->func = func; | |
8939 | func[i]->aux->func_cnt = env->subprog_cnt; | |
1c2a088a | 8940 | } |
f910cefa | 8941 | for (i = 0; i < env->subprog_cnt; i++) { |
1c2a088a AS |
8942 | old_bpf_func = func[i]->bpf_func; |
8943 | tmp = bpf_int_jit_compile(func[i]); | |
8944 | if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) { | |
8945 | verbose(env, "JIT doesn't support bpf-to-bpf calls\n"); | |
c7a89784 | 8946 | err = -ENOTSUPP; |
1c2a088a AS |
8947 | goto out_free; |
8948 | } | |
8949 | cond_resched(); | |
8950 | } | |
8951 | ||
8952 | /* finally lock prog and jit images for all functions and | |
8953 | * populate kallsysm | |
8954 | */ | |
f910cefa | 8955 | for (i = 0; i < env->subprog_cnt; i++) { |
1c2a088a AS |
8956 | bpf_prog_lock_ro(func[i]); |
8957 | bpf_prog_kallsyms_add(func[i]); | |
8958 | } | |
7105e828 DB |
8959 | |
8960 | /* Last step: make now unused interpreter insns from main | |
8961 | * prog consistent for later dump requests, so they can | |
8962 | * later look the same as if they were interpreted only. | |
8963 | */ | |
8964 | for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { | |
7105e828 DB |
8965 | if (insn->code != (BPF_JMP | BPF_CALL) || |
8966 | insn->src_reg != BPF_PSEUDO_CALL) | |
8967 | continue; | |
8968 | insn->off = env->insn_aux_data[i].call_imm; | |
8969 | subprog = find_subprog(env, i + insn->off + 1); | |
dbecd738 | 8970 | insn->imm = subprog; |
7105e828 DB |
8971 | } |
8972 | ||
1c2a088a AS |
8973 | prog->jited = 1; |
8974 | prog->bpf_func = func[0]->bpf_func; | |
8975 | prog->aux->func = func; | |
f910cefa | 8976 | prog->aux->func_cnt = env->subprog_cnt; |
c454a46b | 8977 | bpf_prog_free_unused_jited_linfo(prog); |
1c2a088a AS |
8978 | return 0; |
8979 | out_free: | |
f910cefa | 8980 | for (i = 0; i < env->subprog_cnt; i++) |
1c2a088a AS |
8981 | if (func[i]) |
8982 | bpf_jit_free(func[i]); | |
8983 | kfree(func); | |
c7a89784 | 8984 | out_undo_insn: |
1c2a088a AS |
8985 | /* cleanup main prog to be interpreted */ |
8986 | prog->jit_requested = 0; | |
8987 | for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { | |
8988 | if (insn->code != (BPF_JMP | BPF_CALL) || | |
8989 | insn->src_reg != BPF_PSEUDO_CALL) | |
8990 | continue; | |
8991 | insn->off = 0; | |
8992 | insn->imm = env->insn_aux_data[i].call_imm; | |
8993 | } | |
c454a46b | 8994 | bpf_prog_free_jited_linfo(prog); |
1c2a088a AS |
8995 | return err; |
8996 | } | |
8997 | ||
1ea47e01 AS |
8998 | static int fixup_call_args(struct bpf_verifier_env *env) |
8999 | { | |
19d28fbd | 9000 | #ifndef CONFIG_BPF_JIT_ALWAYS_ON |
1ea47e01 AS |
9001 | struct bpf_prog *prog = env->prog; |
9002 | struct bpf_insn *insn = prog->insnsi; | |
9003 | int i, depth; | |
19d28fbd | 9004 | #endif |
e4052d06 | 9005 | int err = 0; |
1ea47e01 | 9006 | |
e4052d06 QM |
9007 | if (env->prog->jit_requested && |
9008 | !bpf_prog_is_dev_bound(env->prog->aux)) { | |
19d28fbd DM |
9009 | err = jit_subprogs(env); |
9010 | if (err == 0) | |
1c2a088a | 9011 | return 0; |
c7a89784 DB |
9012 | if (err == -EFAULT) |
9013 | return err; | |
19d28fbd DM |
9014 | } |
9015 | #ifndef CONFIG_BPF_JIT_ALWAYS_ON | |
1ea47e01 AS |
9016 | for (i = 0; i < prog->len; i++, insn++) { |
9017 | if (insn->code != (BPF_JMP | BPF_CALL) || | |
9018 | insn->src_reg != BPF_PSEUDO_CALL) | |
9019 | continue; | |
9020 | depth = get_callee_stack_depth(env, insn, i); | |
9021 | if (depth < 0) | |
9022 | return depth; | |
9023 | bpf_patch_call_args(insn, depth); | |
9024 | } | |
19d28fbd DM |
9025 | err = 0; |
9026 | #endif | |
9027 | return err; | |
1ea47e01 AS |
9028 | } |
9029 | ||
79741b3b | 9030 | /* fixup insn->imm field of bpf_call instructions |
81ed18ab | 9031 | * and inline eligible helpers as explicit sequence of BPF instructions |
e245c5c6 AS |
9032 | * |
9033 | * this function is called after eBPF program passed verification | |
9034 | */ | |
79741b3b | 9035 | static int fixup_bpf_calls(struct bpf_verifier_env *env) |
e245c5c6 | 9036 | { |
79741b3b AS |
9037 | struct bpf_prog *prog = env->prog; |
9038 | struct bpf_insn *insn = prog->insnsi; | |
e245c5c6 | 9039 | const struct bpf_func_proto *fn; |
79741b3b | 9040 | const int insn_cnt = prog->len; |
09772d92 | 9041 | const struct bpf_map_ops *ops; |
c93552c4 | 9042 | struct bpf_insn_aux_data *aux; |
81ed18ab AS |
9043 | struct bpf_insn insn_buf[16]; |
9044 | struct bpf_prog *new_prog; | |
9045 | struct bpf_map *map_ptr; | |
9046 | int i, cnt, delta = 0; | |
e245c5c6 | 9047 | |
79741b3b | 9048 | for (i = 0; i < insn_cnt; i++, insn++) { |
f6b1b3bf DB |
9049 | if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) || |
9050 | insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) || | |
9051 | insn->code == (BPF_ALU | BPF_MOD | BPF_X) || | |
68fda450 | 9052 | insn->code == (BPF_ALU | BPF_DIV | BPF_X)) { |
f6b1b3bf DB |
9053 | bool is64 = BPF_CLASS(insn->code) == BPF_ALU64; |
9054 | struct bpf_insn mask_and_div[] = { | |
9055 | BPF_MOV32_REG(insn->src_reg, insn->src_reg), | |
9056 | /* Rx div 0 -> 0 */ | |
9057 | BPF_JMP_IMM(BPF_JNE, insn->src_reg, 0, 2), | |
9058 | BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg), | |
9059 | BPF_JMP_IMM(BPF_JA, 0, 0, 1), | |
9060 | *insn, | |
9061 | }; | |
9062 | struct bpf_insn mask_and_mod[] = { | |
9063 | BPF_MOV32_REG(insn->src_reg, insn->src_reg), | |
9064 | /* Rx mod 0 -> Rx */ | |
9065 | BPF_JMP_IMM(BPF_JEQ, insn->src_reg, 0, 1), | |
9066 | *insn, | |
9067 | }; | |
9068 | struct bpf_insn *patchlet; | |
9069 | ||
9070 | if (insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) || | |
9071 | insn->code == (BPF_ALU | BPF_DIV | BPF_X)) { | |
9072 | patchlet = mask_and_div + (is64 ? 1 : 0); | |
9073 | cnt = ARRAY_SIZE(mask_and_div) - (is64 ? 1 : 0); | |
9074 | } else { | |
9075 | patchlet = mask_and_mod + (is64 ? 1 : 0); | |
9076 | cnt = ARRAY_SIZE(mask_and_mod) - (is64 ? 1 : 0); | |
9077 | } | |
9078 | ||
9079 | new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt); | |
68fda450 AS |
9080 | if (!new_prog) |
9081 | return -ENOMEM; | |
9082 | ||
9083 | delta += cnt - 1; | |
9084 | env->prog = prog = new_prog; | |
9085 | insn = new_prog->insnsi + i + delta; | |
9086 | continue; | |
9087 | } | |
9088 | ||
e0cea7ce DB |
9089 | if (BPF_CLASS(insn->code) == BPF_LD && |
9090 | (BPF_MODE(insn->code) == BPF_ABS || | |
9091 | BPF_MODE(insn->code) == BPF_IND)) { | |
9092 | cnt = env->ops->gen_ld_abs(insn, insn_buf); | |
9093 | if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) { | |
9094 | verbose(env, "bpf verifier is misconfigured\n"); | |
9095 | return -EINVAL; | |
9096 | } | |
9097 | ||
9098 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); | |
9099 | if (!new_prog) | |
9100 | return -ENOMEM; | |
9101 | ||
9102 | delta += cnt - 1; | |
9103 | env->prog = prog = new_prog; | |
9104 | insn = new_prog->insnsi + i + delta; | |
9105 | continue; | |
9106 | } | |
9107 | ||
979d63d5 DB |
9108 | if (insn->code == (BPF_ALU64 | BPF_ADD | BPF_X) || |
9109 | insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) { | |
9110 | const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X; | |
9111 | const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X; | |
9112 | struct bpf_insn insn_buf[16]; | |
9113 | struct bpf_insn *patch = &insn_buf[0]; | |
9114 | bool issrc, isneg; | |
9115 | u32 off_reg; | |
9116 | ||
9117 | aux = &env->insn_aux_data[i + delta]; | |
3612af78 DB |
9118 | if (!aux->alu_state || |
9119 | aux->alu_state == BPF_ALU_NON_POINTER) | |
979d63d5 DB |
9120 | continue; |
9121 | ||
9122 | isneg = aux->alu_state & BPF_ALU_NEG_VALUE; | |
9123 | issrc = (aux->alu_state & BPF_ALU_SANITIZE) == | |
9124 | BPF_ALU_SANITIZE_SRC; | |
9125 | ||
9126 | off_reg = issrc ? insn->src_reg : insn->dst_reg; | |
9127 | if (isneg) | |
9128 | *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1); | |
9129 | *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit - 1); | |
9130 | *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg); | |
9131 | *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg); | |
9132 | *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0); | |
9133 | *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63); | |
9134 | if (issrc) { | |
9135 | *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX, | |
9136 | off_reg); | |
9137 | insn->src_reg = BPF_REG_AX; | |
9138 | } else { | |
9139 | *patch++ = BPF_ALU64_REG(BPF_AND, off_reg, | |
9140 | BPF_REG_AX); | |
9141 | } | |
9142 | if (isneg) | |
9143 | insn->code = insn->code == code_add ? | |
9144 | code_sub : code_add; | |
9145 | *patch++ = *insn; | |
9146 | if (issrc && isneg) | |
9147 | *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1); | |
9148 | cnt = patch - insn_buf; | |
9149 | ||
9150 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); | |
9151 | if (!new_prog) | |
9152 | return -ENOMEM; | |
9153 | ||
9154 | delta += cnt - 1; | |
9155 | env->prog = prog = new_prog; | |
9156 | insn = new_prog->insnsi + i + delta; | |
9157 | continue; | |
9158 | } | |
9159 | ||
79741b3b AS |
9160 | if (insn->code != (BPF_JMP | BPF_CALL)) |
9161 | continue; | |
cc8b0b92 AS |
9162 | if (insn->src_reg == BPF_PSEUDO_CALL) |
9163 | continue; | |
e245c5c6 | 9164 | |
79741b3b AS |
9165 | if (insn->imm == BPF_FUNC_get_route_realm) |
9166 | prog->dst_needed = 1; | |
9167 | if (insn->imm == BPF_FUNC_get_prandom_u32) | |
9168 | bpf_user_rnd_init_once(); | |
9802d865 JB |
9169 | if (insn->imm == BPF_FUNC_override_return) |
9170 | prog->kprobe_override = 1; | |
79741b3b | 9171 | if (insn->imm == BPF_FUNC_tail_call) { |
7b9f6da1 DM |
9172 | /* If we tail call into other programs, we |
9173 | * cannot make any assumptions since they can | |
9174 | * be replaced dynamically during runtime in | |
9175 | * the program array. | |
9176 | */ | |
9177 | prog->cb_access = 1; | |
80a58d02 | 9178 | env->prog->aux->stack_depth = MAX_BPF_STACK; |
e647815a | 9179 | env->prog->aux->max_pkt_offset = MAX_PACKET_OFF; |
7b9f6da1 | 9180 | |
79741b3b AS |
9181 | /* mark bpf_tail_call as different opcode to avoid |
9182 | * conditional branch in the interpeter for every normal | |
9183 | * call and to prevent accidental JITing by JIT compiler | |
9184 | * that doesn't support bpf_tail_call yet | |
e245c5c6 | 9185 | */ |
79741b3b | 9186 | insn->imm = 0; |
71189fa9 | 9187 | insn->code = BPF_JMP | BPF_TAIL_CALL; |
b2157399 | 9188 | |
c93552c4 DB |
9189 | aux = &env->insn_aux_data[i + delta]; |
9190 | if (!bpf_map_ptr_unpriv(aux)) | |
9191 | continue; | |
9192 | ||
b2157399 AS |
9193 | /* instead of changing every JIT dealing with tail_call |
9194 | * emit two extra insns: | |
9195 | * if (index >= max_entries) goto out; | |
9196 | * index &= array->index_mask; | |
9197 | * to avoid out-of-bounds cpu speculation | |
9198 | */ | |
c93552c4 | 9199 | if (bpf_map_ptr_poisoned(aux)) { |
40950343 | 9200 | verbose(env, "tail_call abusing map_ptr\n"); |
b2157399 AS |
9201 | return -EINVAL; |
9202 | } | |
c93552c4 DB |
9203 | |
9204 | map_ptr = BPF_MAP_PTR(aux->map_state); | |
b2157399 AS |
9205 | insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3, |
9206 | map_ptr->max_entries, 2); | |
9207 | insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3, | |
9208 | container_of(map_ptr, | |
9209 | struct bpf_array, | |
9210 | map)->index_mask); | |
9211 | insn_buf[2] = *insn; | |
9212 | cnt = 3; | |
9213 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); | |
9214 | if (!new_prog) | |
9215 | return -ENOMEM; | |
9216 | ||
9217 | delta += cnt - 1; | |
9218 | env->prog = prog = new_prog; | |
9219 | insn = new_prog->insnsi + i + delta; | |
79741b3b AS |
9220 | continue; |
9221 | } | |
e245c5c6 | 9222 | |
89c63074 | 9223 | /* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup |
09772d92 DB |
9224 | * and other inlining handlers are currently limited to 64 bit |
9225 | * only. | |
89c63074 | 9226 | */ |
60b58afc | 9227 | if (prog->jit_requested && BITS_PER_LONG == 64 && |
09772d92 DB |
9228 | (insn->imm == BPF_FUNC_map_lookup_elem || |
9229 | insn->imm == BPF_FUNC_map_update_elem || | |
84430d42 DB |
9230 | insn->imm == BPF_FUNC_map_delete_elem || |
9231 | insn->imm == BPF_FUNC_map_push_elem || | |
9232 | insn->imm == BPF_FUNC_map_pop_elem || | |
9233 | insn->imm == BPF_FUNC_map_peek_elem)) { | |
c93552c4 DB |
9234 | aux = &env->insn_aux_data[i + delta]; |
9235 | if (bpf_map_ptr_poisoned(aux)) | |
9236 | goto patch_call_imm; | |
9237 | ||
9238 | map_ptr = BPF_MAP_PTR(aux->map_state); | |
09772d92 DB |
9239 | ops = map_ptr->ops; |
9240 | if (insn->imm == BPF_FUNC_map_lookup_elem && | |
9241 | ops->map_gen_lookup) { | |
9242 | cnt = ops->map_gen_lookup(map_ptr, insn_buf); | |
9243 | if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) { | |
9244 | verbose(env, "bpf verifier is misconfigured\n"); | |
9245 | return -EINVAL; | |
9246 | } | |
81ed18ab | 9247 | |
09772d92 DB |
9248 | new_prog = bpf_patch_insn_data(env, i + delta, |
9249 | insn_buf, cnt); | |
9250 | if (!new_prog) | |
9251 | return -ENOMEM; | |
81ed18ab | 9252 | |
09772d92 DB |
9253 | delta += cnt - 1; |
9254 | env->prog = prog = new_prog; | |
9255 | insn = new_prog->insnsi + i + delta; | |
9256 | continue; | |
9257 | } | |
81ed18ab | 9258 | |
09772d92 DB |
9259 | BUILD_BUG_ON(!__same_type(ops->map_lookup_elem, |
9260 | (void *(*)(struct bpf_map *map, void *key))NULL)); | |
9261 | BUILD_BUG_ON(!__same_type(ops->map_delete_elem, | |
9262 | (int (*)(struct bpf_map *map, void *key))NULL)); | |
9263 | BUILD_BUG_ON(!__same_type(ops->map_update_elem, | |
9264 | (int (*)(struct bpf_map *map, void *key, void *value, | |
9265 | u64 flags))NULL)); | |
84430d42 DB |
9266 | BUILD_BUG_ON(!__same_type(ops->map_push_elem, |
9267 | (int (*)(struct bpf_map *map, void *value, | |
9268 | u64 flags))NULL)); | |
9269 | BUILD_BUG_ON(!__same_type(ops->map_pop_elem, | |
9270 | (int (*)(struct bpf_map *map, void *value))NULL)); | |
9271 | BUILD_BUG_ON(!__same_type(ops->map_peek_elem, | |
9272 | (int (*)(struct bpf_map *map, void *value))NULL)); | |
9273 | ||
09772d92 DB |
9274 | switch (insn->imm) { |
9275 | case BPF_FUNC_map_lookup_elem: | |
9276 | insn->imm = BPF_CAST_CALL(ops->map_lookup_elem) - | |
9277 | __bpf_call_base; | |
9278 | continue; | |
9279 | case BPF_FUNC_map_update_elem: | |
9280 | insn->imm = BPF_CAST_CALL(ops->map_update_elem) - | |
9281 | __bpf_call_base; | |
9282 | continue; | |
9283 | case BPF_FUNC_map_delete_elem: | |
9284 | insn->imm = BPF_CAST_CALL(ops->map_delete_elem) - | |
9285 | __bpf_call_base; | |
9286 | continue; | |
84430d42 DB |
9287 | case BPF_FUNC_map_push_elem: |
9288 | insn->imm = BPF_CAST_CALL(ops->map_push_elem) - | |
9289 | __bpf_call_base; | |
9290 | continue; | |
9291 | case BPF_FUNC_map_pop_elem: | |
9292 | insn->imm = BPF_CAST_CALL(ops->map_pop_elem) - | |
9293 | __bpf_call_base; | |
9294 | continue; | |
9295 | case BPF_FUNC_map_peek_elem: | |
9296 | insn->imm = BPF_CAST_CALL(ops->map_peek_elem) - | |
9297 | __bpf_call_base; | |
9298 | continue; | |
09772d92 | 9299 | } |
81ed18ab | 9300 | |
09772d92 | 9301 | goto patch_call_imm; |
81ed18ab AS |
9302 | } |
9303 | ||
9304 | patch_call_imm: | |
5e43f899 | 9305 | fn = env->ops->get_func_proto(insn->imm, env->prog); |
79741b3b AS |
9306 | /* all functions that have prototype and verifier allowed |
9307 | * programs to call them, must be real in-kernel functions | |
9308 | */ | |
9309 | if (!fn->func) { | |
61bd5218 JK |
9310 | verbose(env, |
9311 | "kernel subsystem misconfigured func %s#%d\n", | |
79741b3b AS |
9312 | func_id_name(insn->imm), insn->imm); |
9313 | return -EFAULT; | |
e245c5c6 | 9314 | } |
79741b3b | 9315 | insn->imm = fn->func - __bpf_call_base; |
e245c5c6 | 9316 | } |
e245c5c6 | 9317 | |
79741b3b AS |
9318 | return 0; |
9319 | } | |
e245c5c6 | 9320 | |
58e2af8b | 9321 | static void free_states(struct bpf_verifier_env *env) |
f1bca824 | 9322 | { |
58e2af8b | 9323 | struct bpf_verifier_state_list *sl, *sln; |
f1bca824 AS |
9324 | int i; |
9325 | ||
9f4686c4 AS |
9326 | sl = env->free_list; |
9327 | while (sl) { | |
9328 | sln = sl->next; | |
9329 | free_verifier_state(&sl->state, false); | |
9330 | kfree(sl); | |
9331 | sl = sln; | |
9332 | } | |
9333 | ||
f1bca824 AS |
9334 | if (!env->explored_states) |
9335 | return; | |
9336 | ||
dc2a4ebc | 9337 | for (i = 0; i < state_htab_size(env); i++) { |
f1bca824 AS |
9338 | sl = env->explored_states[i]; |
9339 | ||
a8f500af AS |
9340 | while (sl) { |
9341 | sln = sl->next; | |
9342 | free_verifier_state(&sl->state, false); | |
9343 | kfree(sl); | |
9344 | sl = sln; | |
9345 | } | |
f1bca824 AS |
9346 | } |
9347 | ||
71dde681 | 9348 | kvfree(env->explored_states); |
f1bca824 AS |
9349 | } |
9350 | ||
06ee7115 AS |
9351 | static void print_verification_stats(struct bpf_verifier_env *env) |
9352 | { | |
9353 | int i; | |
9354 | ||
9355 | if (env->log.level & BPF_LOG_STATS) { | |
9356 | verbose(env, "verification time %lld usec\n", | |
9357 | div_u64(env->verification_time, 1000)); | |
9358 | verbose(env, "stack depth "); | |
9359 | for (i = 0; i < env->subprog_cnt; i++) { | |
9360 | u32 depth = env->subprog_info[i].stack_depth; | |
9361 | ||
9362 | verbose(env, "%d", depth); | |
9363 | if (i + 1 < env->subprog_cnt) | |
9364 | verbose(env, "+"); | |
9365 | } | |
9366 | verbose(env, "\n"); | |
9367 | } | |
9368 | verbose(env, "processed %d insns (limit %d) max_states_per_insn %d " | |
9369 | "total_states %d peak_states %d mark_read %d\n", | |
9370 | env->insn_processed, BPF_COMPLEXITY_LIMIT_INSNS, | |
9371 | env->max_states_per_insn, env->total_states, | |
9372 | env->peak_states, env->longest_mark_read_walk); | |
f1bca824 AS |
9373 | } |
9374 | ||
38207291 MKL |
9375 | static int check_attach_btf_id(struct bpf_verifier_env *env) |
9376 | { | |
9377 | struct bpf_prog *prog = env->prog; | |
9378 | u32 btf_id = prog->aux->attach_btf_id; | |
9379 | const struct btf_type *t; | |
9380 | const char *tname; | |
9381 | ||
9382 | if (prog->type == BPF_PROG_TYPE_RAW_TRACEPOINT && btf_id) { | |
9383 | const char prefix[] = "btf_trace_"; | |
9384 | ||
9385 | t = btf_type_by_id(btf_vmlinux, btf_id); | |
9386 | if (!t) { | |
9387 | verbose(env, "attach_btf_id %u is invalid\n", btf_id); | |
9388 | return -EINVAL; | |
9389 | } | |
9390 | if (!btf_type_is_typedef(t)) { | |
9391 | verbose(env, "attach_btf_id %u is not a typedef\n", | |
9392 | btf_id); | |
9393 | return -EINVAL; | |
9394 | } | |
9395 | tname = btf_name_by_offset(btf_vmlinux, t->name_off); | |
9396 | if (!tname || strncmp(prefix, tname, sizeof(prefix) - 1)) { | |
9397 | verbose(env, "attach_btf_id %u points to wrong type name %s\n", | |
9398 | btf_id, tname); | |
9399 | return -EINVAL; | |
9400 | } | |
9401 | tname += sizeof(prefix) - 1; | |
9402 | t = btf_type_by_id(btf_vmlinux, t->type); | |
9403 | if (!btf_type_is_ptr(t)) | |
9404 | /* should never happen in valid vmlinux build */ | |
9405 | return -EINVAL; | |
9406 | t = btf_type_by_id(btf_vmlinux, t->type); | |
9407 | if (!btf_type_is_func_proto(t)) | |
9408 | /* should never happen in valid vmlinux build */ | |
9409 | return -EINVAL; | |
9410 | ||
9411 | /* remember two read only pointers that are valid for | |
9412 | * the life time of the kernel | |
9413 | */ | |
9414 | prog->aux->attach_func_name = tname; | |
9415 | prog->aux->attach_func_proto = t; | |
9416 | prog->aux->attach_btf_trace = true; | |
9417 | } | |
9418 | return 0; | |
9419 | } | |
9420 | ||
838e9690 YS |
9421 | int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, |
9422 | union bpf_attr __user *uattr) | |
51580e79 | 9423 | { |
06ee7115 | 9424 | u64 start_time = ktime_get_ns(); |
58e2af8b | 9425 | struct bpf_verifier_env *env; |
b9193c1b | 9426 | struct bpf_verifier_log *log; |
9e4c24e7 | 9427 | int i, len, ret = -EINVAL; |
e2ae4ca2 | 9428 | bool is_priv; |
51580e79 | 9429 | |
eba0c929 AB |
9430 | /* no program is valid */ |
9431 | if (ARRAY_SIZE(bpf_verifier_ops) == 0) | |
9432 | return -EINVAL; | |
9433 | ||
58e2af8b | 9434 | /* 'struct bpf_verifier_env' can be global, but since it's not small, |
cbd35700 AS |
9435 | * allocate/free it every time bpf_check() is called |
9436 | */ | |
58e2af8b | 9437 | env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL); |
cbd35700 AS |
9438 | if (!env) |
9439 | return -ENOMEM; | |
61bd5218 | 9440 | log = &env->log; |
cbd35700 | 9441 | |
9e4c24e7 | 9442 | len = (*prog)->len; |
fad953ce | 9443 | env->insn_aux_data = |
9e4c24e7 | 9444 | vzalloc(array_size(sizeof(struct bpf_insn_aux_data), len)); |
3df126f3 JK |
9445 | ret = -ENOMEM; |
9446 | if (!env->insn_aux_data) | |
9447 | goto err_free_env; | |
9e4c24e7 JK |
9448 | for (i = 0; i < len; i++) |
9449 | env->insn_aux_data[i].orig_idx = i; | |
9bac3d6d | 9450 | env->prog = *prog; |
00176a34 | 9451 | env->ops = bpf_verifier_ops[env->prog->type]; |
45a73c17 | 9452 | is_priv = capable(CAP_SYS_ADMIN); |
0246e64d | 9453 | |
8580ac94 AS |
9454 | if (!btf_vmlinux && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) { |
9455 | mutex_lock(&bpf_verifier_lock); | |
9456 | if (!btf_vmlinux) | |
9457 | btf_vmlinux = btf_parse_vmlinux(); | |
9458 | mutex_unlock(&bpf_verifier_lock); | |
9459 | } | |
9460 | ||
cbd35700 | 9461 | /* grab the mutex to protect few globals used by verifier */ |
45a73c17 AS |
9462 | if (!is_priv) |
9463 | mutex_lock(&bpf_verifier_lock); | |
cbd35700 AS |
9464 | |
9465 | if (attr->log_level || attr->log_buf || attr->log_size) { | |
9466 | /* user requested verbose verifier output | |
9467 | * and supplied buffer to store the verification trace | |
9468 | */ | |
e7bf8249 JK |
9469 | log->level = attr->log_level; |
9470 | log->ubuf = (char __user *) (unsigned long) attr->log_buf; | |
9471 | log->len_total = attr->log_size; | |
cbd35700 AS |
9472 | |
9473 | ret = -EINVAL; | |
e7bf8249 | 9474 | /* log attributes have to be sane */ |
7a9f5c65 | 9475 | if (log->len_total < 128 || log->len_total > UINT_MAX >> 2 || |
06ee7115 | 9476 | !log->level || !log->ubuf || log->level & ~BPF_LOG_MASK) |
3df126f3 | 9477 | goto err_unlock; |
cbd35700 | 9478 | } |
1ad2f583 | 9479 | |
8580ac94 AS |
9480 | if (IS_ERR(btf_vmlinux)) { |
9481 | /* Either gcc or pahole or kernel are broken. */ | |
9482 | verbose(env, "in-kernel BTF is malformed\n"); | |
9483 | ret = PTR_ERR(btf_vmlinux); | |
38207291 | 9484 | goto skip_full_check; |
8580ac94 AS |
9485 | } |
9486 | ||
38207291 MKL |
9487 | ret = check_attach_btf_id(env); |
9488 | if (ret) | |
9489 | goto skip_full_check; | |
9490 | ||
1ad2f583 DB |
9491 | env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT); |
9492 | if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) | |
e07b98d9 | 9493 | env->strict_alignment = true; |
e9ee9efc DM |
9494 | if (attr->prog_flags & BPF_F_ANY_ALIGNMENT) |
9495 | env->strict_alignment = false; | |
cbd35700 | 9496 | |
e2ae4ca2 JK |
9497 | env->allow_ptr_leaks = is_priv; |
9498 | ||
10d274e8 AS |
9499 | if (is_priv) |
9500 | env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ; | |
9501 | ||
f4e3ec0d JK |
9502 | ret = replace_map_fd_with_map_ptr(env); |
9503 | if (ret < 0) | |
9504 | goto skip_full_check; | |
9505 | ||
cae1927c | 9506 | if (bpf_prog_is_dev_bound(env->prog->aux)) { |
a40a2632 | 9507 | ret = bpf_prog_offload_verifier_prep(env->prog); |
ab3f0063 | 9508 | if (ret) |
f4e3ec0d | 9509 | goto skip_full_check; |
ab3f0063 JK |
9510 | } |
9511 | ||
dc2a4ebc | 9512 | env->explored_states = kvcalloc(state_htab_size(env), |
58e2af8b | 9513 | sizeof(struct bpf_verifier_state_list *), |
f1bca824 AS |
9514 | GFP_USER); |
9515 | ret = -ENOMEM; | |
9516 | if (!env->explored_states) | |
9517 | goto skip_full_check; | |
9518 | ||
d9762e84 | 9519 | ret = check_subprogs(env); |
475fb78f AS |
9520 | if (ret < 0) |
9521 | goto skip_full_check; | |
9522 | ||
c454a46b | 9523 | ret = check_btf_info(env, attr, uattr); |
838e9690 YS |
9524 | if (ret < 0) |
9525 | goto skip_full_check; | |
9526 | ||
d9762e84 MKL |
9527 | ret = check_cfg(env); |
9528 | if (ret < 0) | |
9529 | goto skip_full_check; | |
9530 | ||
17a52670 | 9531 | ret = do_check(env); |
8c01c4f8 CG |
9532 | if (env->cur_state) { |
9533 | free_verifier_state(env->cur_state, true); | |
9534 | env->cur_state = NULL; | |
9535 | } | |
cbd35700 | 9536 | |
c941ce9c QM |
9537 | if (ret == 0 && bpf_prog_is_dev_bound(env->prog->aux)) |
9538 | ret = bpf_prog_offload_finalize(env); | |
9539 | ||
0246e64d | 9540 | skip_full_check: |
638f5b90 | 9541 | while (!pop_stack(env, NULL, NULL)); |
f1bca824 | 9542 | free_states(env); |
0246e64d | 9543 | |
c131187d | 9544 | if (ret == 0) |
9b38c405 | 9545 | ret = check_max_stack_depth(env); |
c131187d | 9546 | |
9b38c405 | 9547 | /* instruction rewrites happen after this point */ |
e2ae4ca2 JK |
9548 | if (is_priv) { |
9549 | if (ret == 0) | |
9550 | opt_hard_wire_dead_code_branches(env); | |
52875a04 JK |
9551 | if (ret == 0) |
9552 | ret = opt_remove_dead_code(env); | |
a1b14abc JK |
9553 | if (ret == 0) |
9554 | ret = opt_remove_nops(env); | |
52875a04 JK |
9555 | } else { |
9556 | if (ret == 0) | |
9557 | sanitize_dead_code(env); | |
e2ae4ca2 JK |
9558 | } |
9559 | ||
9bac3d6d AS |
9560 | if (ret == 0) |
9561 | /* program is valid, convert *(u32*)(ctx + off) accesses */ | |
9562 | ret = convert_ctx_accesses(env); | |
9563 | ||
e245c5c6 | 9564 | if (ret == 0) |
79741b3b | 9565 | ret = fixup_bpf_calls(env); |
e245c5c6 | 9566 | |
a4b1d3c1 JW |
9567 | /* do 32-bit optimization after insn patching has done so those patched |
9568 | * insns could be handled correctly. | |
9569 | */ | |
d6c2308c JW |
9570 | if (ret == 0 && !bpf_prog_is_dev_bound(env->prog->aux)) { |
9571 | ret = opt_subreg_zext_lo32_rnd_hi32(env, attr); | |
9572 | env->prog->aux->verifier_zext = bpf_jit_needs_zext() ? !ret | |
9573 | : false; | |
a4b1d3c1 JW |
9574 | } |
9575 | ||
1ea47e01 AS |
9576 | if (ret == 0) |
9577 | ret = fixup_call_args(env); | |
9578 | ||
06ee7115 AS |
9579 | env->verification_time = ktime_get_ns() - start_time; |
9580 | print_verification_stats(env); | |
9581 | ||
a2a7d570 | 9582 | if (log->level && bpf_verifier_log_full(log)) |
cbd35700 | 9583 | ret = -ENOSPC; |
a2a7d570 | 9584 | if (log->level && !log->ubuf) { |
cbd35700 | 9585 | ret = -EFAULT; |
a2a7d570 | 9586 | goto err_release_maps; |
cbd35700 AS |
9587 | } |
9588 | ||
0246e64d AS |
9589 | if (ret == 0 && env->used_map_cnt) { |
9590 | /* if program passed verifier, update used_maps in bpf_prog_info */ | |
9bac3d6d AS |
9591 | env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt, |
9592 | sizeof(env->used_maps[0]), | |
9593 | GFP_KERNEL); | |
0246e64d | 9594 | |
9bac3d6d | 9595 | if (!env->prog->aux->used_maps) { |
0246e64d | 9596 | ret = -ENOMEM; |
a2a7d570 | 9597 | goto err_release_maps; |
0246e64d AS |
9598 | } |
9599 | ||
9bac3d6d | 9600 | memcpy(env->prog->aux->used_maps, env->used_maps, |
0246e64d | 9601 | sizeof(env->used_maps[0]) * env->used_map_cnt); |
9bac3d6d | 9602 | env->prog->aux->used_map_cnt = env->used_map_cnt; |
0246e64d AS |
9603 | |
9604 | /* program is valid. Convert pseudo bpf_ld_imm64 into generic | |
9605 | * bpf_ld_imm64 instructions | |
9606 | */ | |
9607 | convert_pseudo_ld_imm64(env); | |
9608 | } | |
cbd35700 | 9609 | |
ba64e7d8 YS |
9610 | if (ret == 0) |
9611 | adjust_btf_func(env); | |
9612 | ||
a2a7d570 | 9613 | err_release_maps: |
9bac3d6d | 9614 | if (!env->prog->aux->used_maps) |
0246e64d | 9615 | /* if we didn't copy map pointers into bpf_prog_info, release |
ab7f5bf0 | 9616 | * them now. Otherwise free_used_maps() will release them. |
0246e64d AS |
9617 | */ |
9618 | release_maps(env); | |
9bac3d6d | 9619 | *prog = env->prog; |
3df126f3 | 9620 | err_unlock: |
45a73c17 AS |
9621 | if (!is_priv) |
9622 | mutex_unlock(&bpf_verifier_lock); | |
3df126f3 JK |
9623 | vfree(env->insn_aux_data); |
9624 | err_free_env: | |
9625 | kfree(env); | |
51580e79 AS |
9626 | return ret; |
9627 | } |