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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; |
33ff9823 DB |
208 | }; |
209 | ||
cbd35700 AS |
210 | static DEFINE_MUTEX(bpf_verifier_lock); |
211 | ||
d9762e84 MKL |
212 | static const struct bpf_line_info * |
213 | find_linfo(const struct bpf_verifier_env *env, u32 insn_off) | |
214 | { | |
215 | const struct bpf_line_info *linfo; | |
216 | const struct bpf_prog *prog; | |
217 | u32 i, nr_linfo; | |
218 | ||
219 | prog = env->prog; | |
220 | nr_linfo = prog->aux->nr_linfo; | |
221 | ||
222 | if (!nr_linfo || insn_off >= prog->len) | |
223 | return NULL; | |
224 | ||
225 | linfo = prog->aux->linfo; | |
226 | for (i = 1; i < nr_linfo; i++) | |
227 | if (insn_off < linfo[i].insn_off) | |
228 | break; | |
229 | ||
230 | return &linfo[i - 1]; | |
231 | } | |
232 | ||
77d2e05a MKL |
233 | void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt, |
234 | va_list args) | |
cbd35700 | 235 | { |
a2a7d570 | 236 | unsigned int n; |
cbd35700 | 237 | |
a2a7d570 | 238 | n = vscnprintf(log->kbuf, BPF_VERIFIER_TMP_LOG_SIZE, fmt, args); |
a2a7d570 JK |
239 | |
240 | WARN_ONCE(n >= BPF_VERIFIER_TMP_LOG_SIZE - 1, | |
241 | "verifier log line truncated - local buffer too short\n"); | |
242 | ||
243 | n = min(log->len_total - log->len_used - 1, n); | |
244 | log->kbuf[n] = '\0'; | |
245 | ||
246 | if (!copy_to_user(log->ubuf + log->len_used, log->kbuf, n + 1)) | |
247 | log->len_used += n; | |
248 | else | |
249 | log->ubuf = NULL; | |
cbd35700 | 250 | } |
abe08840 JO |
251 | |
252 | /* log_level controls verbosity level of eBPF verifier. | |
253 | * bpf_verifier_log_write() is used to dump the verification trace to the log, | |
254 | * so the user can figure out what's wrong with the program | |
430e68d1 | 255 | */ |
abe08840 JO |
256 | __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env, |
257 | const char *fmt, ...) | |
258 | { | |
259 | va_list args; | |
260 | ||
77d2e05a MKL |
261 | if (!bpf_verifier_log_needed(&env->log)) |
262 | return; | |
263 | ||
abe08840 | 264 | va_start(args, fmt); |
77d2e05a | 265 | bpf_verifier_vlog(&env->log, fmt, args); |
abe08840 JO |
266 | va_end(args); |
267 | } | |
268 | EXPORT_SYMBOL_GPL(bpf_verifier_log_write); | |
269 | ||
270 | __printf(2, 3) static void verbose(void *private_data, const char *fmt, ...) | |
271 | { | |
77d2e05a | 272 | struct bpf_verifier_env *env = private_data; |
abe08840 JO |
273 | va_list args; |
274 | ||
77d2e05a MKL |
275 | if (!bpf_verifier_log_needed(&env->log)) |
276 | return; | |
277 | ||
abe08840 | 278 | va_start(args, fmt); |
77d2e05a | 279 | bpf_verifier_vlog(&env->log, fmt, args); |
abe08840 JO |
280 | va_end(args); |
281 | } | |
cbd35700 | 282 | |
d9762e84 MKL |
283 | static const char *ltrim(const char *s) |
284 | { | |
285 | while (isspace(*s)) | |
286 | s++; | |
287 | ||
288 | return s; | |
289 | } | |
290 | ||
291 | __printf(3, 4) static void verbose_linfo(struct bpf_verifier_env *env, | |
292 | u32 insn_off, | |
293 | const char *prefix_fmt, ...) | |
294 | { | |
295 | const struct bpf_line_info *linfo; | |
296 | ||
297 | if (!bpf_verifier_log_needed(&env->log)) | |
298 | return; | |
299 | ||
300 | linfo = find_linfo(env, insn_off); | |
301 | if (!linfo || linfo == env->prev_linfo) | |
302 | return; | |
303 | ||
304 | if (prefix_fmt) { | |
305 | va_list args; | |
306 | ||
307 | va_start(args, prefix_fmt); | |
308 | bpf_verifier_vlog(&env->log, prefix_fmt, args); | |
309 | va_end(args); | |
310 | } | |
311 | ||
312 | verbose(env, "%s\n", | |
313 | ltrim(btf_name_by_offset(env->prog->aux->btf, | |
314 | linfo->line_off))); | |
315 | ||
316 | env->prev_linfo = linfo; | |
317 | } | |
318 | ||
de8f3a83 DB |
319 | static bool type_is_pkt_pointer(enum bpf_reg_type type) |
320 | { | |
321 | return type == PTR_TO_PACKET || | |
322 | type == PTR_TO_PACKET_META; | |
323 | } | |
324 | ||
46f8bc92 MKL |
325 | static bool type_is_sk_pointer(enum bpf_reg_type type) |
326 | { | |
327 | return type == PTR_TO_SOCKET || | |
655a51e5 | 328 | type == PTR_TO_SOCK_COMMON || |
fada7fdc JL |
329 | type == PTR_TO_TCP_SOCK || |
330 | type == PTR_TO_XDP_SOCK; | |
46f8bc92 MKL |
331 | } |
332 | ||
840b9615 JS |
333 | static bool reg_type_may_be_null(enum bpf_reg_type type) |
334 | { | |
fd978bf7 | 335 | return type == PTR_TO_MAP_VALUE_OR_NULL || |
46f8bc92 | 336 | type == PTR_TO_SOCKET_OR_NULL || |
655a51e5 MKL |
337 | type == PTR_TO_SOCK_COMMON_OR_NULL || |
338 | type == PTR_TO_TCP_SOCK_OR_NULL; | |
fd978bf7 JS |
339 | } |
340 | ||
d83525ca AS |
341 | static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg) |
342 | { | |
343 | return reg->type == PTR_TO_MAP_VALUE && | |
344 | map_value_has_spin_lock(reg->map_ptr); | |
345 | } | |
346 | ||
cba368c1 MKL |
347 | static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type) |
348 | { | |
349 | return type == PTR_TO_SOCKET || | |
350 | type == PTR_TO_SOCKET_OR_NULL || | |
351 | type == PTR_TO_TCP_SOCK || | |
352 | type == PTR_TO_TCP_SOCK_OR_NULL; | |
353 | } | |
354 | ||
1b986589 | 355 | static bool arg_type_may_be_refcounted(enum bpf_arg_type type) |
fd978bf7 | 356 | { |
1b986589 | 357 | return type == ARG_PTR_TO_SOCK_COMMON; |
fd978bf7 JS |
358 | } |
359 | ||
360 | /* Determine whether the function releases some resources allocated by another | |
361 | * function call. The first reference type argument will be assumed to be | |
362 | * released by release_reference(). | |
363 | */ | |
364 | static bool is_release_function(enum bpf_func_id func_id) | |
365 | { | |
6acc9b43 | 366 | return func_id == BPF_FUNC_sk_release; |
840b9615 JS |
367 | } |
368 | ||
46f8bc92 MKL |
369 | static bool is_acquire_function(enum bpf_func_id func_id) |
370 | { | |
371 | return func_id == BPF_FUNC_sk_lookup_tcp || | |
edbf8c01 LB |
372 | func_id == BPF_FUNC_sk_lookup_udp || |
373 | func_id == BPF_FUNC_skc_lookup_tcp; | |
46f8bc92 MKL |
374 | } |
375 | ||
1b986589 MKL |
376 | static bool is_ptr_cast_function(enum bpf_func_id func_id) |
377 | { | |
378 | return func_id == BPF_FUNC_tcp_sock || | |
379 | func_id == BPF_FUNC_sk_fullsock; | |
380 | } | |
381 | ||
17a52670 AS |
382 | /* string representation of 'enum bpf_reg_type' */ |
383 | static const char * const reg_type_str[] = { | |
384 | [NOT_INIT] = "?", | |
f1174f77 | 385 | [SCALAR_VALUE] = "inv", |
17a52670 AS |
386 | [PTR_TO_CTX] = "ctx", |
387 | [CONST_PTR_TO_MAP] = "map_ptr", | |
388 | [PTR_TO_MAP_VALUE] = "map_value", | |
389 | [PTR_TO_MAP_VALUE_OR_NULL] = "map_value_or_null", | |
17a52670 | 390 | [PTR_TO_STACK] = "fp", |
969bf05e | 391 | [PTR_TO_PACKET] = "pkt", |
de8f3a83 | 392 | [PTR_TO_PACKET_META] = "pkt_meta", |
969bf05e | 393 | [PTR_TO_PACKET_END] = "pkt_end", |
d58e468b | 394 | [PTR_TO_FLOW_KEYS] = "flow_keys", |
c64b7983 JS |
395 | [PTR_TO_SOCKET] = "sock", |
396 | [PTR_TO_SOCKET_OR_NULL] = "sock_or_null", | |
46f8bc92 MKL |
397 | [PTR_TO_SOCK_COMMON] = "sock_common", |
398 | [PTR_TO_SOCK_COMMON_OR_NULL] = "sock_common_or_null", | |
655a51e5 MKL |
399 | [PTR_TO_TCP_SOCK] = "tcp_sock", |
400 | [PTR_TO_TCP_SOCK_OR_NULL] = "tcp_sock_or_null", | |
9df1c28b | 401 | [PTR_TO_TP_BUFFER] = "tp_buffer", |
fada7fdc | 402 | [PTR_TO_XDP_SOCK] = "xdp_sock", |
17a52670 AS |
403 | }; |
404 | ||
8efea21d EC |
405 | static char slot_type_char[] = { |
406 | [STACK_INVALID] = '?', | |
407 | [STACK_SPILL] = 'r', | |
408 | [STACK_MISC] = 'm', | |
409 | [STACK_ZERO] = '0', | |
410 | }; | |
411 | ||
4e92024a AS |
412 | static void print_liveness(struct bpf_verifier_env *env, |
413 | enum bpf_reg_liveness live) | |
414 | { | |
9242b5f5 | 415 | if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN | REG_LIVE_DONE)) |
4e92024a AS |
416 | verbose(env, "_"); |
417 | if (live & REG_LIVE_READ) | |
418 | verbose(env, "r"); | |
419 | if (live & REG_LIVE_WRITTEN) | |
420 | verbose(env, "w"); | |
9242b5f5 AS |
421 | if (live & REG_LIVE_DONE) |
422 | verbose(env, "D"); | |
4e92024a AS |
423 | } |
424 | ||
f4d7e40a AS |
425 | static struct bpf_func_state *func(struct bpf_verifier_env *env, |
426 | const struct bpf_reg_state *reg) | |
427 | { | |
428 | struct bpf_verifier_state *cur = env->cur_state; | |
429 | ||
430 | return cur->frame[reg->frameno]; | |
431 | } | |
432 | ||
61bd5218 | 433 | static void print_verifier_state(struct bpf_verifier_env *env, |
f4d7e40a | 434 | const struct bpf_func_state *state) |
17a52670 | 435 | { |
f4d7e40a | 436 | const struct bpf_reg_state *reg; |
17a52670 AS |
437 | enum bpf_reg_type t; |
438 | int i; | |
439 | ||
f4d7e40a AS |
440 | if (state->frameno) |
441 | verbose(env, " frame%d:", state->frameno); | |
17a52670 | 442 | for (i = 0; i < MAX_BPF_REG; i++) { |
1a0dc1ac AS |
443 | reg = &state->regs[i]; |
444 | t = reg->type; | |
17a52670 AS |
445 | if (t == NOT_INIT) |
446 | continue; | |
4e92024a AS |
447 | verbose(env, " R%d", i); |
448 | print_liveness(env, reg->live); | |
449 | verbose(env, "=%s", reg_type_str[t]); | |
b5dc0163 AS |
450 | if (t == SCALAR_VALUE && reg->precise) |
451 | verbose(env, "P"); | |
f1174f77 EC |
452 | if ((t == SCALAR_VALUE || t == PTR_TO_STACK) && |
453 | tnum_is_const(reg->var_off)) { | |
454 | /* reg->off should be 0 for SCALAR_VALUE */ | |
61bd5218 | 455 | verbose(env, "%lld", reg->var_off.value + reg->off); |
f1174f77 | 456 | } else { |
cba368c1 MKL |
457 | verbose(env, "(id=%d", reg->id); |
458 | if (reg_type_may_be_refcounted_or_null(t)) | |
459 | verbose(env, ",ref_obj_id=%d", reg->ref_obj_id); | |
f1174f77 | 460 | if (t != SCALAR_VALUE) |
61bd5218 | 461 | verbose(env, ",off=%d", reg->off); |
de8f3a83 | 462 | if (type_is_pkt_pointer(t)) |
61bd5218 | 463 | verbose(env, ",r=%d", reg->range); |
f1174f77 EC |
464 | else if (t == CONST_PTR_TO_MAP || |
465 | t == PTR_TO_MAP_VALUE || | |
466 | t == PTR_TO_MAP_VALUE_OR_NULL) | |
61bd5218 | 467 | verbose(env, ",ks=%d,vs=%d", |
f1174f77 EC |
468 | reg->map_ptr->key_size, |
469 | reg->map_ptr->value_size); | |
7d1238f2 EC |
470 | if (tnum_is_const(reg->var_off)) { |
471 | /* Typically an immediate SCALAR_VALUE, but | |
472 | * could be a pointer whose offset is too big | |
473 | * for reg->off | |
474 | */ | |
61bd5218 | 475 | verbose(env, ",imm=%llx", reg->var_off.value); |
7d1238f2 EC |
476 | } else { |
477 | if (reg->smin_value != reg->umin_value && | |
478 | reg->smin_value != S64_MIN) | |
61bd5218 | 479 | verbose(env, ",smin_value=%lld", |
7d1238f2 EC |
480 | (long long)reg->smin_value); |
481 | if (reg->smax_value != reg->umax_value && | |
482 | reg->smax_value != S64_MAX) | |
61bd5218 | 483 | verbose(env, ",smax_value=%lld", |
7d1238f2 EC |
484 | (long long)reg->smax_value); |
485 | if (reg->umin_value != 0) | |
61bd5218 | 486 | verbose(env, ",umin_value=%llu", |
7d1238f2 EC |
487 | (unsigned long long)reg->umin_value); |
488 | if (reg->umax_value != U64_MAX) | |
61bd5218 | 489 | verbose(env, ",umax_value=%llu", |
7d1238f2 EC |
490 | (unsigned long long)reg->umax_value); |
491 | if (!tnum_is_unknown(reg->var_off)) { | |
492 | char tn_buf[48]; | |
f1174f77 | 493 | |
7d1238f2 | 494 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); |
61bd5218 | 495 | verbose(env, ",var_off=%s", tn_buf); |
7d1238f2 | 496 | } |
f1174f77 | 497 | } |
61bd5218 | 498 | verbose(env, ")"); |
f1174f77 | 499 | } |
17a52670 | 500 | } |
638f5b90 | 501 | for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) { |
8efea21d EC |
502 | char types_buf[BPF_REG_SIZE + 1]; |
503 | bool valid = false; | |
504 | int j; | |
505 | ||
506 | for (j = 0; j < BPF_REG_SIZE; j++) { | |
507 | if (state->stack[i].slot_type[j] != STACK_INVALID) | |
508 | valid = true; | |
509 | types_buf[j] = slot_type_char[ | |
510 | state->stack[i].slot_type[j]]; | |
511 | } | |
512 | types_buf[BPF_REG_SIZE] = 0; | |
513 | if (!valid) | |
514 | continue; | |
515 | verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE); | |
516 | print_liveness(env, state->stack[i].spilled_ptr.live); | |
b5dc0163 AS |
517 | if (state->stack[i].slot_type[0] == STACK_SPILL) { |
518 | reg = &state->stack[i].spilled_ptr; | |
519 | t = reg->type; | |
520 | verbose(env, "=%s", reg_type_str[t]); | |
521 | if (t == SCALAR_VALUE && reg->precise) | |
522 | verbose(env, "P"); | |
523 | if (t == SCALAR_VALUE && tnum_is_const(reg->var_off)) | |
524 | verbose(env, "%lld", reg->var_off.value + reg->off); | |
525 | } else { | |
8efea21d | 526 | verbose(env, "=%s", types_buf); |
b5dc0163 | 527 | } |
17a52670 | 528 | } |
fd978bf7 JS |
529 | if (state->acquired_refs && state->refs[0].id) { |
530 | verbose(env, " refs=%d", state->refs[0].id); | |
531 | for (i = 1; i < state->acquired_refs; i++) | |
532 | if (state->refs[i].id) | |
533 | verbose(env, ",%d", state->refs[i].id); | |
534 | } | |
61bd5218 | 535 | verbose(env, "\n"); |
17a52670 AS |
536 | } |
537 | ||
84dbf350 JS |
538 | #define COPY_STATE_FN(NAME, COUNT, FIELD, SIZE) \ |
539 | static int copy_##NAME##_state(struct bpf_func_state *dst, \ | |
540 | const struct bpf_func_state *src) \ | |
541 | { \ | |
542 | if (!src->FIELD) \ | |
543 | return 0; \ | |
544 | if (WARN_ON_ONCE(dst->COUNT < src->COUNT)) { \ | |
545 | /* internal bug, make state invalid to reject the program */ \ | |
546 | memset(dst, 0, sizeof(*dst)); \ | |
547 | return -EFAULT; \ | |
548 | } \ | |
549 | memcpy(dst->FIELD, src->FIELD, \ | |
550 | sizeof(*src->FIELD) * (src->COUNT / SIZE)); \ | |
551 | return 0; \ | |
638f5b90 | 552 | } |
fd978bf7 JS |
553 | /* copy_reference_state() */ |
554 | COPY_STATE_FN(reference, acquired_refs, refs, 1) | |
84dbf350 JS |
555 | /* copy_stack_state() */ |
556 | COPY_STATE_FN(stack, allocated_stack, stack, BPF_REG_SIZE) | |
557 | #undef COPY_STATE_FN | |
558 | ||
559 | #define REALLOC_STATE_FN(NAME, COUNT, FIELD, SIZE) \ | |
560 | static int realloc_##NAME##_state(struct bpf_func_state *state, int size, \ | |
561 | bool copy_old) \ | |
562 | { \ | |
563 | u32 old_size = state->COUNT; \ | |
564 | struct bpf_##NAME##_state *new_##FIELD; \ | |
565 | int slot = size / SIZE; \ | |
566 | \ | |
567 | if (size <= old_size || !size) { \ | |
568 | if (copy_old) \ | |
569 | return 0; \ | |
570 | state->COUNT = slot * SIZE; \ | |
571 | if (!size && old_size) { \ | |
572 | kfree(state->FIELD); \ | |
573 | state->FIELD = NULL; \ | |
574 | } \ | |
575 | return 0; \ | |
576 | } \ | |
577 | new_##FIELD = kmalloc_array(slot, sizeof(struct bpf_##NAME##_state), \ | |
578 | GFP_KERNEL); \ | |
579 | if (!new_##FIELD) \ | |
580 | return -ENOMEM; \ | |
581 | if (copy_old) { \ | |
582 | if (state->FIELD) \ | |
583 | memcpy(new_##FIELD, state->FIELD, \ | |
584 | sizeof(*new_##FIELD) * (old_size / SIZE)); \ | |
585 | memset(new_##FIELD + old_size / SIZE, 0, \ | |
586 | sizeof(*new_##FIELD) * (size - old_size) / SIZE); \ | |
587 | } \ | |
588 | state->COUNT = slot * SIZE; \ | |
589 | kfree(state->FIELD); \ | |
590 | state->FIELD = new_##FIELD; \ | |
591 | return 0; \ | |
592 | } | |
fd978bf7 JS |
593 | /* realloc_reference_state() */ |
594 | REALLOC_STATE_FN(reference, acquired_refs, refs, 1) | |
84dbf350 JS |
595 | /* realloc_stack_state() */ |
596 | REALLOC_STATE_FN(stack, allocated_stack, stack, BPF_REG_SIZE) | |
597 | #undef REALLOC_STATE_FN | |
638f5b90 AS |
598 | |
599 | /* do_check() starts with zero-sized stack in struct bpf_verifier_state to | |
600 | * make it consume minimal amount of memory. check_stack_write() access from | |
f4d7e40a | 601 | * the program calls into realloc_func_state() to grow the stack size. |
84dbf350 JS |
602 | * Note there is a non-zero 'parent' pointer inside bpf_verifier_state |
603 | * which realloc_stack_state() copies over. It points to previous | |
604 | * bpf_verifier_state which is never reallocated. | |
638f5b90 | 605 | */ |
fd978bf7 JS |
606 | static int realloc_func_state(struct bpf_func_state *state, int stack_size, |
607 | int refs_size, bool copy_old) | |
638f5b90 | 608 | { |
fd978bf7 JS |
609 | int err = realloc_reference_state(state, refs_size, copy_old); |
610 | if (err) | |
611 | return err; | |
612 | return realloc_stack_state(state, stack_size, copy_old); | |
613 | } | |
614 | ||
615 | /* Acquire a pointer id from the env and update the state->refs to include | |
616 | * this new pointer reference. | |
617 | * On success, returns a valid pointer id to associate with the register | |
618 | * On failure, returns a negative errno. | |
638f5b90 | 619 | */ |
fd978bf7 | 620 | static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx) |
638f5b90 | 621 | { |
fd978bf7 JS |
622 | struct bpf_func_state *state = cur_func(env); |
623 | int new_ofs = state->acquired_refs; | |
624 | int id, err; | |
625 | ||
626 | err = realloc_reference_state(state, state->acquired_refs + 1, true); | |
627 | if (err) | |
628 | return err; | |
629 | id = ++env->id_gen; | |
630 | state->refs[new_ofs].id = id; | |
631 | state->refs[new_ofs].insn_idx = insn_idx; | |
638f5b90 | 632 | |
fd978bf7 JS |
633 | return id; |
634 | } | |
635 | ||
636 | /* release function corresponding to acquire_reference_state(). Idempotent. */ | |
46f8bc92 | 637 | static int release_reference_state(struct bpf_func_state *state, int ptr_id) |
fd978bf7 JS |
638 | { |
639 | int i, last_idx; | |
640 | ||
fd978bf7 JS |
641 | last_idx = state->acquired_refs - 1; |
642 | for (i = 0; i < state->acquired_refs; i++) { | |
643 | if (state->refs[i].id == ptr_id) { | |
644 | if (last_idx && i != last_idx) | |
645 | memcpy(&state->refs[i], &state->refs[last_idx], | |
646 | sizeof(*state->refs)); | |
647 | memset(&state->refs[last_idx], 0, sizeof(*state->refs)); | |
648 | state->acquired_refs--; | |
638f5b90 | 649 | return 0; |
638f5b90 | 650 | } |
638f5b90 | 651 | } |
46f8bc92 | 652 | return -EINVAL; |
fd978bf7 JS |
653 | } |
654 | ||
655 | static int transfer_reference_state(struct bpf_func_state *dst, | |
656 | struct bpf_func_state *src) | |
657 | { | |
658 | int err = realloc_reference_state(dst, src->acquired_refs, false); | |
659 | if (err) | |
660 | return err; | |
661 | err = copy_reference_state(dst, src); | |
662 | if (err) | |
663 | return err; | |
638f5b90 AS |
664 | return 0; |
665 | } | |
666 | ||
f4d7e40a AS |
667 | static void free_func_state(struct bpf_func_state *state) |
668 | { | |
5896351e AS |
669 | if (!state) |
670 | return; | |
fd978bf7 | 671 | kfree(state->refs); |
f4d7e40a AS |
672 | kfree(state->stack); |
673 | kfree(state); | |
674 | } | |
675 | ||
b5dc0163 AS |
676 | static void clear_jmp_history(struct bpf_verifier_state *state) |
677 | { | |
678 | kfree(state->jmp_history); | |
679 | state->jmp_history = NULL; | |
680 | state->jmp_history_cnt = 0; | |
681 | } | |
682 | ||
1969db47 AS |
683 | static void free_verifier_state(struct bpf_verifier_state *state, |
684 | bool free_self) | |
638f5b90 | 685 | { |
f4d7e40a AS |
686 | int i; |
687 | ||
688 | for (i = 0; i <= state->curframe; i++) { | |
689 | free_func_state(state->frame[i]); | |
690 | state->frame[i] = NULL; | |
691 | } | |
b5dc0163 | 692 | clear_jmp_history(state); |
1969db47 AS |
693 | if (free_self) |
694 | kfree(state); | |
638f5b90 AS |
695 | } |
696 | ||
697 | /* copy verifier state from src to dst growing dst stack space | |
698 | * when necessary to accommodate larger src stack | |
699 | */ | |
f4d7e40a AS |
700 | static int copy_func_state(struct bpf_func_state *dst, |
701 | const struct bpf_func_state *src) | |
638f5b90 AS |
702 | { |
703 | int err; | |
704 | ||
fd978bf7 JS |
705 | err = realloc_func_state(dst, src->allocated_stack, src->acquired_refs, |
706 | false); | |
707 | if (err) | |
708 | return err; | |
709 | memcpy(dst, src, offsetof(struct bpf_func_state, acquired_refs)); | |
710 | err = copy_reference_state(dst, src); | |
638f5b90 AS |
711 | if (err) |
712 | return err; | |
638f5b90 AS |
713 | return copy_stack_state(dst, src); |
714 | } | |
715 | ||
f4d7e40a AS |
716 | static int copy_verifier_state(struct bpf_verifier_state *dst_state, |
717 | const struct bpf_verifier_state *src) | |
718 | { | |
719 | struct bpf_func_state *dst; | |
b5dc0163 | 720 | u32 jmp_sz = sizeof(struct bpf_idx_pair) * src->jmp_history_cnt; |
f4d7e40a AS |
721 | int i, err; |
722 | ||
b5dc0163 AS |
723 | if (dst_state->jmp_history_cnt < src->jmp_history_cnt) { |
724 | kfree(dst_state->jmp_history); | |
725 | dst_state->jmp_history = kmalloc(jmp_sz, GFP_USER); | |
726 | if (!dst_state->jmp_history) | |
727 | return -ENOMEM; | |
728 | } | |
729 | memcpy(dst_state->jmp_history, src->jmp_history, jmp_sz); | |
730 | dst_state->jmp_history_cnt = src->jmp_history_cnt; | |
731 | ||
f4d7e40a AS |
732 | /* if dst has more stack frames then src frame, free them */ |
733 | for (i = src->curframe + 1; i <= dst_state->curframe; i++) { | |
734 | free_func_state(dst_state->frame[i]); | |
735 | dst_state->frame[i] = NULL; | |
736 | } | |
979d63d5 | 737 | dst_state->speculative = src->speculative; |
f4d7e40a | 738 | dst_state->curframe = src->curframe; |
d83525ca | 739 | dst_state->active_spin_lock = src->active_spin_lock; |
2589726d AS |
740 | dst_state->branches = src->branches; |
741 | dst_state->parent = src->parent; | |
b5dc0163 AS |
742 | dst_state->first_insn_idx = src->first_insn_idx; |
743 | dst_state->last_insn_idx = src->last_insn_idx; | |
f4d7e40a AS |
744 | for (i = 0; i <= src->curframe; i++) { |
745 | dst = dst_state->frame[i]; | |
746 | if (!dst) { | |
747 | dst = kzalloc(sizeof(*dst), GFP_KERNEL); | |
748 | if (!dst) | |
749 | return -ENOMEM; | |
750 | dst_state->frame[i] = dst; | |
751 | } | |
752 | err = copy_func_state(dst, src->frame[i]); | |
753 | if (err) | |
754 | return err; | |
755 | } | |
756 | return 0; | |
757 | } | |
758 | ||
2589726d AS |
759 | static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st) |
760 | { | |
761 | while (st) { | |
762 | u32 br = --st->branches; | |
763 | ||
764 | /* WARN_ON(br > 1) technically makes sense here, | |
765 | * but see comment in push_stack(), hence: | |
766 | */ | |
767 | WARN_ONCE((int)br < 0, | |
768 | "BUG update_branch_counts:branches_to_explore=%d\n", | |
769 | br); | |
770 | if (br) | |
771 | break; | |
772 | st = st->parent; | |
773 | } | |
774 | } | |
775 | ||
638f5b90 AS |
776 | static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx, |
777 | int *insn_idx) | |
778 | { | |
779 | struct bpf_verifier_state *cur = env->cur_state; | |
780 | struct bpf_verifier_stack_elem *elem, *head = env->head; | |
781 | int err; | |
17a52670 AS |
782 | |
783 | if (env->head == NULL) | |
638f5b90 | 784 | return -ENOENT; |
17a52670 | 785 | |
638f5b90 AS |
786 | if (cur) { |
787 | err = copy_verifier_state(cur, &head->st); | |
788 | if (err) | |
789 | return err; | |
790 | } | |
791 | if (insn_idx) | |
792 | *insn_idx = head->insn_idx; | |
17a52670 | 793 | if (prev_insn_idx) |
638f5b90 AS |
794 | *prev_insn_idx = head->prev_insn_idx; |
795 | elem = head->next; | |
1969db47 | 796 | free_verifier_state(&head->st, false); |
638f5b90 | 797 | kfree(head); |
17a52670 AS |
798 | env->head = elem; |
799 | env->stack_size--; | |
638f5b90 | 800 | return 0; |
17a52670 AS |
801 | } |
802 | ||
58e2af8b | 803 | static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env, |
979d63d5 DB |
804 | int insn_idx, int prev_insn_idx, |
805 | bool speculative) | |
17a52670 | 806 | { |
638f5b90 | 807 | struct bpf_verifier_state *cur = env->cur_state; |
58e2af8b | 808 | struct bpf_verifier_stack_elem *elem; |
638f5b90 | 809 | int err; |
17a52670 | 810 | |
638f5b90 | 811 | elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL); |
17a52670 AS |
812 | if (!elem) |
813 | goto err; | |
814 | ||
17a52670 AS |
815 | elem->insn_idx = insn_idx; |
816 | elem->prev_insn_idx = prev_insn_idx; | |
817 | elem->next = env->head; | |
818 | env->head = elem; | |
819 | env->stack_size++; | |
1969db47 AS |
820 | err = copy_verifier_state(&elem->st, cur); |
821 | if (err) | |
822 | goto err; | |
979d63d5 | 823 | elem->st.speculative |= speculative; |
b285fcb7 AS |
824 | if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) { |
825 | verbose(env, "The sequence of %d jumps is too complex.\n", | |
826 | env->stack_size); | |
17a52670 AS |
827 | goto err; |
828 | } | |
2589726d AS |
829 | if (elem->st.parent) { |
830 | ++elem->st.parent->branches; | |
831 | /* WARN_ON(branches > 2) technically makes sense here, | |
832 | * but | |
833 | * 1. speculative states will bump 'branches' for non-branch | |
834 | * instructions | |
835 | * 2. is_state_visited() heuristics may decide not to create | |
836 | * a new state for a sequence of branches and all such current | |
837 | * and cloned states will be pointing to a single parent state | |
838 | * which might have large 'branches' count. | |
839 | */ | |
840 | } | |
17a52670 AS |
841 | return &elem->st; |
842 | err: | |
5896351e AS |
843 | free_verifier_state(env->cur_state, true); |
844 | env->cur_state = NULL; | |
17a52670 | 845 | /* pop all elements and return */ |
638f5b90 | 846 | while (!pop_stack(env, NULL, NULL)); |
17a52670 AS |
847 | return NULL; |
848 | } | |
849 | ||
850 | #define CALLER_SAVED_REGS 6 | |
851 | static const int caller_saved[CALLER_SAVED_REGS] = { | |
852 | BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5 | |
853 | }; | |
854 | ||
f1174f77 EC |
855 | static void __mark_reg_not_init(struct bpf_reg_state *reg); |
856 | ||
b03c9f9f EC |
857 | /* Mark the unknown part of a register (variable offset or scalar value) as |
858 | * known to have the value @imm. | |
859 | */ | |
860 | static void __mark_reg_known(struct bpf_reg_state *reg, u64 imm) | |
861 | { | |
a9c676bc AS |
862 | /* Clear id, off, and union(map_ptr, range) */ |
863 | memset(((u8 *)reg) + sizeof(reg->type), 0, | |
864 | offsetof(struct bpf_reg_state, var_off) - sizeof(reg->type)); | |
b03c9f9f EC |
865 | reg->var_off = tnum_const(imm); |
866 | reg->smin_value = (s64)imm; | |
867 | reg->smax_value = (s64)imm; | |
868 | reg->umin_value = imm; | |
869 | reg->umax_value = imm; | |
870 | } | |
871 | ||
f1174f77 EC |
872 | /* Mark the 'variable offset' part of a register as zero. This should be |
873 | * used only on registers holding a pointer type. | |
874 | */ | |
875 | static void __mark_reg_known_zero(struct bpf_reg_state *reg) | |
a9789ef9 | 876 | { |
b03c9f9f | 877 | __mark_reg_known(reg, 0); |
f1174f77 | 878 | } |
a9789ef9 | 879 | |
cc2b14d5 AS |
880 | static void __mark_reg_const_zero(struct bpf_reg_state *reg) |
881 | { | |
882 | __mark_reg_known(reg, 0); | |
cc2b14d5 AS |
883 | reg->type = SCALAR_VALUE; |
884 | } | |
885 | ||
61bd5218 JK |
886 | static void mark_reg_known_zero(struct bpf_verifier_env *env, |
887 | struct bpf_reg_state *regs, u32 regno) | |
f1174f77 EC |
888 | { |
889 | if (WARN_ON(regno >= MAX_BPF_REG)) { | |
61bd5218 | 890 | verbose(env, "mark_reg_known_zero(regs, %u)\n", regno); |
f1174f77 EC |
891 | /* Something bad happened, let's kill all regs */ |
892 | for (regno = 0; regno < MAX_BPF_REG; regno++) | |
893 | __mark_reg_not_init(regs + regno); | |
894 | return; | |
895 | } | |
896 | __mark_reg_known_zero(regs + regno); | |
897 | } | |
898 | ||
de8f3a83 DB |
899 | static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg) |
900 | { | |
901 | return type_is_pkt_pointer(reg->type); | |
902 | } | |
903 | ||
904 | static bool reg_is_pkt_pointer_any(const struct bpf_reg_state *reg) | |
905 | { | |
906 | return reg_is_pkt_pointer(reg) || | |
907 | reg->type == PTR_TO_PACKET_END; | |
908 | } | |
909 | ||
910 | /* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */ | |
911 | static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg, | |
912 | enum bpf_reg_type which) | |
913 | { | |
914 | /* The register can already have a range from prior markings. | |
915 | * This is fine as long as it hasn't been advanced from its | |
916 | * origin. | |
917 | */ | |
918 | return reg->type == which && | |
919 | reg->id == 0 && | |
920 | reg->off == 0 && | |
921 | tnum_equals_const(reg->var_off, 0); | |
922 | } | |
923 | ||
b03c9f9f EC |
924 | /* Attempts to improve min/max values based on var_off information */ |
925 | static void __update_reg_bounds(struct bpf_reg_state *reg) | |
926 | { | |
927 | /* min signed is max(sign bit) | min(other bits) */ | |
928 | reg->smin_value = max_t(s64, reg->smin_value, | |
929 | reg->var_off.value | (reg->var_off.mask & S64_MIN)); | |
930 | /* max signed is min(sign bit) | max(other bits) */ | |
931 | reg->smax_value = min_t(s64, reg->smax_value, | |
932 | reg->var_off.value | (reg->var_off.mask & S64_MAX)); | |
933 | reg->umin_value = max(reg->umin_value, reg->var_off.value); | |
934 | reg->umax_value = min(reg->umax_value, | |
935 | reg->var_off.value | reg->var_off.mask); | |
936 | } | |
937 | ||
938 | /* Uses signed min/max values to inform unsigned, and vice-versa */ | |
939 | static void __reg_deduce_bounds(struct bpf_reg_state *reg) | |
940 | { | |
941 | /* Learn sign from signed bounds. | |
942 | * If we cannot cross the sign boundary, then signed and unsigned bounds | |
943 | * are the same, so combine. This works even in the negative case, e.g. | |
944 | * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff. | |
945 | */ | |
946 | if (reg->smin_value >= 0 || reg->smax_value < 0) { | |
947 | reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value, | |
948 | reg->umin_value); | |
949 | reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value, | |
950 | reg->umax_value); | |
951 | return; | |
952 | } | |
953 | /* Learn sign from unsigned bounds. Signed bounds cross the sign | |
954 | * boundary, so we must be careful. | |
955 | */ | |
956 | if ((s64)reg->umax_value >= 0) { | |
957 | /* Positive. We can't learn anything from the smin, but smax | |
958 | * is positive, hence safe. | |
959 | */ | |
960 | reg->smin_value = reg->umin_value; | |
961 | reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value, | |
962 | reg->umax_value); | |
963 | } else if ((s64)reg->umin_value < 0) { | |
964 | /* Negative. We can't learn anything from the smax, but smin | |
965 | * is negative, hence safe. | |
966 | */ | |
967 | reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value, | |
968 | reg->umin_value); | |
969 | reg->smax_value = reg->umax_value; | |
970 | } | |
971 | } | |
972 | ||
973 | /* Attempts to improve var_off based on unsigned min/max information */ | |
974 | static void __reg_bound_offset(struct bpf_reg_state *reg) | |
975 | { | |
976 | reg->var_off = tnum_intersect(reg->var_off, | |
977 | tnum_range(reg->umin_value, | |
978 | reg->umax_value)); | |
979 | } | |
980 | ||
981 | /* Reset the min/max bounds of a register */ | |
982 | static void __mark_reg_unbounded(struct bpf_reg_state *reg) | |
983 | { | |
984 | reg->smin_value = S64_MIN; | |
985 | reg->smax_value = S64_MAX; | |
986 | reg->umin_value = 0; | |
987 | reg->umax_value = U64_MAX; | |
988 | } | |
989 | ||
f1174f77 EC |
990 | /* Mark a register as having a completely unknown (scalar) value. */ |
991 | static void __mark_reg_unknown(struct bpf_reg_state *reg) | |
992 | { | |
a9c676bc AS |
993 | /* |
994 | * Clear type, id, off, and union(map_ptr, range) and | |
995 | * padding between 'type' and union | |
996 | */ | |
997 | memset(reg, 0, offsetof(struct bpf_reg_state, var_off)); | |
f1174f77 | 998 | reg->type = SCALAR_VALUE; |
f1174f77 | 999 | reg->var_off = tnum_unknown; |
f4d7e40a | 1000 | reg->frameno = 0; |
b03c9f9f | 1001 | __mark_reg_unbounded(reg); |
f1174f77 EC |
1002 | } |
1003 | ||
61bd5218 JK |
1004 | static void mark_reg_unknown(struct bpf_verifier_env *env, |
1005 | struct bpf_reg_state *regs, u32 regno) | |
f1174f77 EC |
1006 | { |
1007 | if (WARN_ON(regno >= MAX_BPF_REG)) { | |
61bd5218 | 1008 | verbose(env, "mark_reg_unknown(regs, %u)\n", regno); |
19ceb417 AS |
1009 | /* Something bad happened, let's kill all regs except FP */ |
1010 | for (regno = 0; regno < BPF_REG_FP; regno++) | |
f1174f77 EC |
1011 | __mark_reg_not_init(regs + regno); |
1012 | return; | |
1013 | } | |
6754172c AS |
1014 | regs += regno; |
1015 | __mark_reg_unknown(regs); | |
1016 | /* constant backtracking is enabled for root without bpf2bpf calls */ | |
1017 | regs->precise = env->subprog_cnt > 1 || !env->allow_ptr_leaks ? | |
1018 | true : false; | |
f1174f77 EC |
1019 | } |
1020 | ||
1021 | static void __mark_reg_not_init(struct bpf_reg_state *reg) | |
1022 | { | |
1023 | __mark_reg_unknown(reg); | |
1024 | reg->type = NOT_INIT; | |
1025 | } | |
1026 | ||
61bd5218 JK |
1027 | static void mark_reg_not_init(struct bpf_verifier_env *env, |
1028 | struct bpf_reg_state *regs, u32 regno) | |
f1174f77 EC |
1029 | { |
1030 | if (WARN_ON(regno >= MAX_BPF_REG)) { | |
61bd5218 | 1031 | verbose(env, "mark_reg_not_init(regs, %u)\n", regno); |
19ceb417 AS |
1032 | /* Something bad happened, let's kill all regs except FP */ |
1033 | for (regno = 0; regno < BPF_REG_FP; regno++) | |
f1174f77 EC |
1034 | __mark_reg_not_init(regs + regno); |
1035 | return; | |
1036 | } | |
1037 | __mark_reg_not_init(regs + regno); | |
a9789ef9 DB |
1038 | } |
1039 | ||
5327ed3d | 1040 | #define DEF_NOT_SUBREG (0) |
61bd5218 | 1041 | static void init_reg_state(struct bpf_verifier_env *env, |
f4d7e40a | 1042 | struct bpf_func_state *state) |
17a52670 | 1043 | { |
f4d7e40a | 1044 | struct bpf_reg_state *regs = state->regs; |
17a52670 AS |
1045 | int i; |
1046 | ||
dc503a8a | 1047 | for (i = 0; i < MAX_BPF_REG; i++) { |
61bd5218 | 1048 | mark_reg_not_init(env, regs, i); |
dc503a8a | 1049 | regs[i].live = REG_LIVE_NONE; |
679c782d | 1050 | regs[i].parent = NULL; |
5327ed3d | 1051 | regs[i].subreg_def = DEF_NOT_SUBREG; |
dc503a8a | 1052 | } |
17a52670 AS |
1053 | |
1054 | /* frame pointer */ | |
f1174f77 | 1055 | regs[BPF_REG_FP].type = PTR_TO_STACK; |
61bd5218 | 1056 | mark_reg_known_zero(env, regs, BPF_REG_FP); |
f4d7e40a | 1057 | regs[BPF_REG_FP].frameno = state->frameno; |
17a52670 AS |
1058 | |
1059 | /* 1st arg to a function */ | |
1060 | regs[BPF_REG_1].type = PTR_TO_CTX; | |
61bd5218 | 1061 | mark_reg_known_zero(env, regs, BPF_REG_1); |
6760bf2d DB |
1062 | } |
1063 | ||
f4d7e40a AS |
1064 | #define BPF_MAIN_FUNC (-1) |
1065 | static void init_func_state(struct bpf_verifier_env *env, | |
1066 | struct bpf_func_state *state, | |
1067 | int callsite, int frameno, int subprogno) | |
1068 | { | |
1069 | state->callsite = callsite; | |
1070 | state->frameno = frameno; | |
1071 | state->subprogno = subprogno; | |
1072 | init_reg_state(env, state); | |
1073 | } | |
1074 | ||
17a52670 AS |
1075 | enum reg_arg_type { |
1076 | SRC_OP, /* register is used as source operand */ | |
1077 | DST_OP, /* register is used as destination operand */ | |
1078 | DST_OP_NO_MARK /* same as above, check only, don't mark */ | |
1079 | }; | |
1080 | ||
cc8b0b92 AS |
1081 | static int cmp_subprogs(const void *a, const void *b) |
1082 | { | |
9c8105bd JW |
1083 | return ((struct bpf_subprog_info *)a)->start - |
1084 | ((struct bpf_subprog_info *)b)->start; | |
cc8b0b92 AS |
1085 | } |
1086 | ||
1087 | static int find_subprog(struct bpf_verifier_env *env, int off) | |
1088 | { | |
9c8105bd | 1089 | struct bpf_subprog_info *p; |
cc8b0b92 | 1090 | |
9c8105bd JW |
1091 | p = bsearch(&off, env->subprog_info, env->subprog_cnt, |
1092 | sizeof(env->subprog_info[0]), cmp_subprogs); | |
cc8b0b92 AS |
1093 | if (!p) |
1094 | return -ENOENT; | |
9c8105bd | 1095 | return p - env->subprog_info; |
cc8b0b92 AS |
1096 | |
1097 | } | |
1098 | ||
1099 | static int add_subprog(struct bpf_verifier_env *env, int off) | |
1100 | { | |
1101 | int insn_cnt = env->prog->len; | |
1102 | int ret; | |
1103 | ||
1104 | if (off >= insn_cnt || off < 0) { | |
1105 | verbose(env, "call to invalid destination\n"); | |
1106 | return -EINVAL; | |
1107 | } | |
1108 | ret = find_subprog(env, off); | |
1109 | if (ret >= 0) | |
1110 | return 0; | |
4cb3d99c | 1111 | if (env->subprog_cnt >= BPF_MAX_SUBPROGS) { |
cc8b0b92 AS |
1112 | verbose(env, "too many subprograms\n"); |
1113 | return -E2BIG; | |
1114 | } | |
9c8105bd JW |
1115 | env->subprog_info[env->subprog_cnt++].start = off; |
1116 | sort(env->subprog_info, env->subprog_cnt, | |
1117 | sizeof(env->subprog_info[0]), cmp_subprogs, NULL); | |
cc8b0b92 AS |
1118 | return 0; |
1119 | } | |
1120 | ||
1121 | static int check_subprogs(struct bpf_verifier_env *env) | |
1122 | { | |
1123 | int i, ret, subprog_start, subprog_end, off, cur_subprog = 0; | |
9c8105bd | 1124 | struct bpf_subprog_info *subprog = env->subprog_info; |
cc8b0b92 AS |
1125 | struct bpf_insn *insn = env->prog->insnsi; |
1126 | int insn_cnt = env->prog->len; | |
1127 | ||
f910cefa JW |
1128 | /* Add entry function. */ |
1129 | ret = add_subprog(env, 0); | |
1130 | if (ret < 0) | |
1131 | return ret; | |
1132 | ||
cc8b0b92 AS |
1133 | /* determine subprog starts. The end is one before the next starts */ |
1134 | for (i = 0; i < insn_cnt; i++) { | |
1135 | if (insn[i].code != (BPF_JMP | BPF_CALL)) | |
1136 | continue; | |
1137 | if (insn[i].src_reg != BPF_PSEUDO_CALL) | |
1138 | continue; | |
1139 | if (!env->allow_ptr_leaks) { | |
1140 | verbose(env, "function calls to other bpf functions are allowed for root only\n"); | |
1141 | return -EPERM; | |
1142 | } | |
cc8b0b92 AS |
1143 | ret = add_subprog(env, i + insn[i].imm + 1); |
1144 | if (ret < 0) | |
1145 | return ret; | |
1146 | } | |
1147 | ||
4cb3d99c JW |
1148 | /* Add a fake 'exit' subprog which could simplify subprog iteration |
1149 | * logic. 'subprog_cnt' should not be increased. | |
1150 | */ | |
1151 | subprog[env->subprog_cnt].start = insn_cnt; | |
1152 | ||
06ee7115 | 1153 | if (env->log.level & BPF_LOG_LEVEL2) |
cc8b0b92 | 1154 | for (i = 0; i < env->subprog_cnt; i++) |
9c8105bd | 1155 | verbose(env, "func#%d @%d\n", i, subprog[i].start); |
cc8b0b92 AS |
1156 | |
1157 | /* now check that all jumps are within the same subprog */ | |
4cb3d99c JW |
1158 | subprog_start = subprog[cur_subprog].start; |
1159 | subprog_end = subprog[cur_subprog + 1].start; | |
cc8b0b92 AS |
1160 | for (i = 0; i < insn_cnt; i++) { |
1161 | u8 code = insn[i].code; | |
1162 | ||
092ed096 | 1163 | if (BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32) |
cc8b0b92 AS |
1164 | goto next; |
1165 | if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL) | |
1166 | goto next; | |
1167 | off = i + insn[i].off + 1; | |
1168 | if (off < subprog_start || off >= subprog_end) { | |
1169 | verbose(env, "jump out of range from insn %d to %d\n", i, off); | |
1170 | return -EINVAL; | |
1171 | } | |
1172 | next: | |
1173 | if (i == subprog_end - 1) { | |
1174 | /* to avoid fall-through from one subprog into another | |
1175 | * the last insn of the subprog should be either exit | |
1176 | * or unconditional jump back | |
1177 | */ | |
1178 | if (code != (BPF_JMP | BPF_EXIT) && | |
1179 | code != (BPF_JMP | BPF_JA)) { | |
1180 | verbose(env, "last insn is not an exit or jmp\n"); | |
1181 | return -EINVAL; | |
1182 | } | |
1183 | subprog_start = subprog_end; | |
4cb3d99c JW |
1184 | cur_subprog++; |
1185 | if (cur_subprog < env->subprog_cnt) | |
9c8105bd | 1186 | subprog_end = subprog[cur_subprog + 1].start; |
cc8b0b92 AS |
1187 | } |
1188 | } | |
1189 | return 0; | |
1190 | } | |
1191 | ||
679c782d EC |
1192 | /* Parentage chain of this register (or stack slot) should take care of all |
1193 | * issues like callee-saved registers, stack slot allocation time, etc. | |
1194 | */ | |
f4d7e40a | 1195 | static int mark_reg_read(struct bpf_verifier_env *env, |
679c782d | 1196 | const struct bpf_reg_state *state, |
5327ed3d | 1197 | struct bpf_reg_state *parent, u8 flag) |
f4d7e40a AS |
1198 | { |
1199 | bool writes = parent == state->parent; /* Observe write marks */ | |
06ee7115 | 1200 | int cnt = 0; |
dc503a8a EC |
1201 | |
1202 | while (parent) { | |
1203 | /* if read wasn't screened by an earlier write ... */ | |
679c782d | 1204 | if (writes && state->live & REG_LIVE_WRITTEN) |
dc503a8a | 1205 | break; |
9242b5f5 AS |
1206 | if (parent->live & REG_LIVE_DONE) { |
1207 | verbose(env, "verifier BUG type %s var_off %lld off %d\n", | |
1208 | reg_type_str[parent->type], | |
1209 | parent->var_off.value, parent->off); | |
1210 | return -EFAULT; | |
1211 | } | |
5327ed3d JW |
1212 | /* The first condition is more likely to be true than the |
1213 | * second, checked it first. | |
1214 | */ | |
1215 | if ((parent->live & REG_LIVE_READ) == flag || | |
1216 | parent->live & REG_LIVE_READ64) | |
25af32da AS |
1217 | /* The parentage chain never changes and |
1218 | * this parent was already marked as LIVE_READ. | |
1219 | * There is no need to keep walking the chain again and | |
1220 | * keep re-marking all parents as LIVE_READ. | |
1221 | * This case happens when the same register is read | |
1222 | * multiple times without writes into it in-between. | |
5327ed3d JW |
1223 | * Also, if parent has the stronger REG_LIVE_READ64 set, |
1224 | * then no need to set the weak REG_LIVE_READ32. | |
25af32da AS |
1225 | */ |
1226 | break; | |
dc503a8a | 1227 | /* ... then we depend on parent's value */ |
5327ed3d JW |
1228 | parent->live |= flag; |
1229 | /* REG_LIVE_READ64 overrides REG_LIVE_READ32. */ | |
1230 | if (flag == REG_LIVE_READ64) | |
1231 | parent->live &= ~REG_LIVE_READ32; | |
dc503a8a EC |
1232 | state = parent; |
1233 | parent = state->parent; | |
f4d7e40a | 1234 | writes = true; |
06ee7115 | 1235 | cnt++; |
dc503a8a | 1236 | } |
06ee7115 AS |
1237 | |
1238 | if (env->longest_mark_read_walk < cnt) | |
1239 | env->longest_mark_read_walk = cnt; | |
f4d7e40a | 1240 | return 0; |
dc503a8a EC |
1241 | } |
1242 | ||
5327ed3d JW |
1243 | /* This function is supposed to be used by the following 32-bit optimization |
1244 | * code only. It returns TRUE if the source or destination register operates | |
1245 | * on 64-bit, otherwise return FALSE. | |
1246 | */ | |
1247 | static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn, | |
1248 | u32 regno, struct bpf_reg_state *reg, enum reg_arg_type t) | |
1249 | { | |
1250 | u8 code, class, op; | |
1251 | ||
1252 | code = insn->code; | |
1253 | class = BPF_CLASS(code); | |
1254 | op = BPF_OP(code); | |
1255 | if (class == BPF_JMP) { | |
1256 | /* BPF_EXIT for "main" will reach here. Return TRUE | |
1257 | * conservatively. | |
1258 | */ | |
1259 | if (op == BPF_EXIT) | |
1260 | return true; | |
1261 | if (op == BPF_CALL) { | |
1262 | /* BPF to BPF call will reach here because of marking | |
1263 | * caller saved clobber with DST_OP_NO_MARK for which we | |
1264 | * don't care the register def because they are anyway | |
1265 | * marked as NOT_INIT already. | |
1266 | */ | |
1267 | if (insn->src_reg == BPF_PSEUDO_CALL) | |
1268 | return false; | |
1269 | /* Helper call will reach here because of arg type | |
1270 | * check, conservatively return TRUE. | |
1271 | */ | |
1272 | if (t == SRC_OP) | |
1273 | return true; | |
1274 | ||
1275 | return false; | |
1276 | } | |
1277 | } | |
1278 | ||
1279 | if (class == BPF_ALU64 || class == BPF_JMP || | |
1280 | /* BPF_END always use BPF_ALU class. */ | |
1281 | (class == BPF_ALU && op == BPF_END && insn->imm == 64)) | |
1282 | return true; | |
1283 | ||
1284 | if (class == BPF_ALU || class == BPF_JMP32) | |
1285 | return false; | |
1286 | ||
1287 | if (class == BPF_LDX) { | |
1288 | if (t != SRC_OP) | |
1289 | return BPF_SIZE(code) == BPF_DW; | |
1290 | /* LDX source must be ptr. */ | |
1291 | return true; | |
1292 | } | |
1293 | ||
1294 | if (class == BPF_STX) { | |
1295 | if (reg->type != SCALAR_VALUE) | |
1296 | return true; | |
1297 | return BPF_SIZE(code) == BPF_DW; | |
1298 | } | |
1299 | ||
1300 | if (class == BPF_LD) { | |
1301 | u8 mode = BPF_MODE(code); | |
1302 | ||
1303 | /* LD_IMM64 */ | |
1304 | if (mode == BPF_IMM) | |
1305 | return true; | |
1306 | ||
1307 | /* Both LD_IND and LD_ABS return 32-bit data. */ | |
1308 | if (t != SRC_OP) | |
1309 | return false; | |
1310 | ||
1311 | /* Implicit ctx ptr. */ | |
1312 | if (regno == BPF_REG_6) | |
1313 | return true; | |
1314 | ||
1315 | /* Explicit source could be any width. */ | |
1316 | return true; | |
1317 | } | |
1318 | ||
1319 | if (class == BPF_ST) | |
1320 | /* The only source register for BPF_ST is a ptr. */ | |
1321 | return true; | |
1322 | ||
1323 | /* Conservatively return true at default. */ | |
1324 | return true; | |
1325 | } | |
1326 | ||
b325fbca JW |
1327 | /* Return TRUE if INSN doesn't have explicit value define. */ |
1328 | static bool insn_no_def(struct bpf_insn *insn) | |
1329 | { | |
1330 | u8 class = BPF_CLASS(insn->code); | |
1331 | ||
1332 | return (class == BPF_JMP || class == BPF_JMP32 || | |
1333 | class == BPF_STX || class == BPF_ST); | |
1334 | } | |
1335 | ||
1336 | /* Return TRUE if INSN has defined any 32-bit value explicitly. */ | |
1337 | static bool insn_has_def32(struct bpf_verifier_env *env, struct bpf_insn *insn) | |
1338 | { | |
1339 | if (insn_no_def(insn)) | |
1340 | return false; | |
1341 | ||
1342 | return !is_reg64(env, insn, insn->dst_reg, NULL, DST_OP); | |
1343 | } | |
1344 | ||
5327ed3d JW |
1345 | static void mark_insn_zext(struct bpf_verifier_env *env, |
1346 | struct bpf_reg_state *reg) | |
1347 | { | |
1348 | s32 def_idx = reg->subreg_def; | |
1349 | ||
1350 | if (def_idx == DEF_NOT_SUBREG) | |
1351 | return; | |
1352 | ||
1353 | env->insn_aux_data[def_idx - 1].zext_dst = true; | |
1354 | /* The dst will be zero extended, so won't be sub-register anymore. */ | |
1355 | reg->subreg_def = DEF_NOT_SUBREG; | |
1356 | } | |
1357 | ||
dc503a8a | 1358 | static int check_reg_arg(struct bpf_verifier_env *env, u32 regno, |
17a52670 AS |
1359 | enum reg_arg_type t) |
1360 | { | |
f4d7e40a AS |
1361 | struct bpf_verifier_state *vstate = env->cur_state; |
1362 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
5327ed3d | 1363 | struct bpf_insn *insn = env->prog->insnsi + env->insn_idx; |
c342dc10 | 1364 | struct bpf_reg_state *reg, *regs = state->regs; |
5327ed3d | 1365 | bool rw64; |
dc503a8a | 1366 | |
17a52670 | 1367 | if (regno >= MAX_BPF_REG) { |
61bd5218 | 1368 | verbose(env, "R%d is invalid\n", regno); |
17a52670 AS |
1369 | return -EINVAL; |
1370 | } | |
1371 | ||
c342dc10 | 1372 | reg = ®s[regno]; |
5327ed3d | 1373 | rw64 = is_reg64(env, insn, regno, reg, t); |
17a52670 AS |
1374 | if (t == SRC_OP) { |
1375 | /* check whether register used as source operand can be read */ | |
c342dc10 | 1376 | if (reg->type == NOT_INIT) { |
61bd5218 | 1377 | verbose(env, "R%d !read_ok\n", regno); |
17a52670 AS |
1378 | return -EACCES; |
1379 | } | |
679c782d | 1380 | /* We don't need to worry about FP liveness because it's read-only */ |
c342dc10 JW |
1381 | if (regno == BPF_REG_FP) |
1382 | return 0; | |
1383 | ||
5327ed3d JW |
1384 | if (rw64) |
1385 | mark_insn_zext(env, reg); | |
1386 | ||
1387 | return mark_reg_read(env, reg, reg->parent, | |
1388 | rw64 ? REG_LIVE_READ64 : REG_LIVE_READ32); | |
17a52670 AS |
1389 | } else { |
1390 | /* check whether register used as dest operand can be written to */ | |
1391 | if (regno == BPF_REG_FP) { | |
61bd5218 | 1392 | verbose(env, "frame pointer is read only\n"); |
17a52670 AS |
1393 | return -EACCES; |
1394 | } | |
c342dc10 | 1395 | reg->live |= REG_LIVE_WRITTEN; |
5327ed3d | 1396 | reg->subreg_def = rw64 ? DEF_NOT_SUBREG : env->insn_idx + 1; |
17a52670 | 1397 | if (t == DST_OP) |
61bd5218 | 1398 | mark_reg_unknown(env, regs, regno); |
17a52670 AS |
1399 | } |
1400 | return 0; | |
1401 | } | |
1402 | ||
b5dc0163 AS |
1403 | /* for any branch, call, exit record the history of jmps in the given state */ |
1404 | static int push_jmp_history(struct bpf_verifier_env *env, | |
1405 | struct bpf_verifier_state *cur) | |
1406 | { | |
1407 | u32 cnt = cur->jmp_history_cnt; | |
1408 | struct bpf_idx_pair *p; | |
1409 | ||
1410 | cnt++; | |
1411 | p = krealloc(cur->jmp_history, cnt * sizeof(*p), GFP_USER); | |
1412 | if (!p) | |
1413 | return -ENOMEM; | |
1414 | p[cnt - 1].idx = env->insn_idx; | |
1415 | p[cnt - 1].prev_idx = env->prev_insn_idx; | |
1416 | cur->jmp_history = p; | |
1417 | cur->jmp_history_cnt = cnt; | |
1418 | return 0; | |
1419 | } | |
1420 | ||
1421 | /* Backtrack one insn at a time. If idx is not at the top of recorded | |
1422 | * history then previous instruction came from straight line execution. | |
1423 | */ | |
1424 | static int get_prev_insn_idx(struct bpf_verifier_state *st, int i, | |
1425 | u32 *history) | |
1426 | { | |
1427 | u32 cnt = *history; | |
1428 | ||
1429 | if (cnt && st->jmp_history[cnt - 1].idx == i) { | |
1430 | i = st->jmp_history[cnt - 1].prev_idx; | |
1431 | (*history)--; | |
1432 | } else { | |
1433 | i--; | |
1434 | } | |
1435 | return i; | |
1436 | } | |
1437 | ||
1438 | /* For given verifier state backtrack_insn() is called from the last insn to | |
1439 | * the first insn. Its purpose is to compute a bitmask of registers and | |
1440 | * stack slots that needs precision in the parent verifier state. | |
1441 | */ | |
1442 | static int backtrack_insn(struct bpf_verifier_env *env, int idx, | |
1443 | u32 *reg_mask, u64 *stack_mask) | |
1444 | { | |
1445 | const struct bpf_insn_cbs cbs = { | |
1446 | .cb_print = verbose, | |
1447 | .private_data = env, | |
1448 | }; | |
1449 | struct bpf_insn *insn = env->prog->insnsi + idx; | |
1450 | u8 class = BPF_CLASS(insn->code); | |
1451 | u8 opcode = BPF_OP(insn->code); | |
1452 | u8 mode = BPF_MODE(insn->code); | |
1453 | u32 dreg = 1u << insn->dst_reg; | |
1454 | u32 sreg = 1u << insn->src_reg; | |
1455 | u32 spi; | |
1456 | ||
1457 | if (insn->code == 0) | |
1458 | return 0; | |
1459 | if (env->log.level & BPF_LOG_LEVEL) { | |
1460 | verbose(env, "regs=%x stack=%llx before ", *reg_mask, *stack_mask); | |
1461 | verbose(env, "%d: ", idx); | |
1462 | print_bpf_insn(&cbs, insn, env->allow_ptr_leaks); | |
1463 | } | |
1464 | ||
1465 | if (class == BPF_ALU || class == BPF_ALU64) { | |
1466 | if (!(*reg_mask & dreg)) | |
1467 | return 0; | |
1468 | if (opcode == BPF_MOV) { | |
1469 | if (BPF_SRC(insn->code) == BPF_X) { | |
1470 | /* dreg = sreg | |
1471 | * dreg needs precision after this insn | |
1472 | * sreg needs precision before this insn | |
1473 | */ | |
1474 | *reg_mask &= ~dreg; | |
1475 | *reg_mask |= sreg; | |
1476 | } else { | |
1477 | /* dreg = K | |
1478 | * dreg needs precision after this insn. | |
1479 | * Corresponding register is already marked | |
1480 | * as precise=true in this verifier state. | |
1481 | * No further markings in parent are necessary | |
1482 | */ | |
1483 | *reg_mask &= ~dreg; | |
1484 | } | |
1485 | } else { | |
1486 | if (BPF_SRC(insn->code) == BPF_X) { | |
1487 | /* dreg += sreg | |
1488 | * both dreg and sreg need precision | |
1489 | * before this insn | |
1490 | */ | |
1491 | *reg_mask |= sreg; | |
1492 | } /* else dreg += K | |
1493 | * dreg still needs precision before this insn | |
1494 | */ | |
1495 | } | |
1496 | } else if (class == BPF_LDX) { | |
1497 | if (!(*reg_mask & dreg)) | |
1498 | return 0; | |
1499 | *reg_mask &= ~dreg; | |
1500 | ||
1501 | /* scalars can only be spilled into stack w/o losing precision. | |
1502 | * Load from any other memory can be zero extended. | |
1503 | * The desire to keep that precision is already indicated | |
1504 | * by 'precise' mark in corresponding register of this state. | |
1505 | * No further tracking necessary. | |
1506 | */ | |
1507 | if (insn->src_reg != BPF_REG_FP) | |
1508 | return 0; | |
1509 | if (BPF_SIZE(insn->code) != BPF_DW) | |
1510 | return 0; | |
1511 | ||
1512 | /* dreg = *(u64 *)[fp - off] was a fill from the stack. | |
1513 | * that [fp - off] slot contains scalar that needs to be | |
1514 | * tracked with precision | |
1515 | */ | |
1516 | spi = (-insn->off - 1) / BPF_REG_SIZE; | |
1517 | if (spi >= 64) { | |
1518 | verbose(env, "BUG spi %d\n", spi); | |
1519 | WARN_ONCE(1, "verifier backtracking bug"); | |
1520 | return -EFAULT; | |
1521 | } | |
1522 | *stack_mask |= 1ull << spi; | |
b3b50f05 | 1523 | } else if (class == BPF_STX || class == BPF_ST) { |
b5dc0163 | 1524 | if (*reg_mask & dreg) |
b3b50f05 | 1525 | /* stx & st shouldn't be using _scalar_ dst_reg |
b5dc0163 AS |
1526 | * to access memory. It means backtracking |
1527 | * encountered a case of pointer subtraction. | |
1528 | */ | |
1529 | return -ENOTSUPP; | |
1530 | /* scalars can only be spilled into stack */ | |
1531 | if (insn->dst_reg != BPF_REG_FP) | |
1532 | return 0; | |
1533 | if (BPF_SIZE(insn->code) != BPF_DW) | |
1534 | return 0; | |
1535 | spi = (-insn->off - 1) / BPF_REG_SIZE; | |
1536 | if (spi >= 64) { | |
1537 | verbose(env, "BUG spi %d\n", spi); | |
1538 | WARN_ONCE(1, "verifier backtracking bug"); | |
1539 | return -EFAULT; | |
1540 | } | |
1541 | if (!(*stack_mask & (1ull << spi))) | |
1542 | return 0; | |
1543 | *stack_mask &= ~(1ull << spi); | |
b3b50f05 AN |
1544 | if (class == BPF_STX) |
1545 | *reg_mask |= sreg; | |
b5dc0163 AS |
1546 | } else if (class == BPF_JMP || class == BPF_JMP32) { |
1547 | if (opcode == BPF_CALL) { | |
1548 | if (insn->src_reg == BPF_PSEUDO_CALL) | |
1549 | return -ENOTSUPP; | |
1550 | /* regular helper call sets R0 */ | |
1551 | *reg_mask &= ~1; | |
1552 | if (*reg_mask & 0x3f) { | |
1553 | /* if backtracing was looking for registers R1-R5 | |
1554 | * they should have been found already. | |
1555 | */ | |
1556 | verbose(env, "BUG regs %x\n", *reg_mask); | |
1557 | WARN_ONCE(1, "verifier backtracking bug"); | |
1558 | return -EFAULT; | |
1559 | } | |
1560 | } else if (opcode == BPF_EXIT) { | |
1561 | return -ENOTSUPP; | |
1562 | } | |
1563 | } else if (class == BPF_LD) { | |
1564 | if (!(*reg_mask & dreg)) | |
1565 | return 0; | |
1566 | *reg_mask &= ~dreg; | |
1567 | /* It's ld_imm64 or ld_abs or ld_ind. | |
1568 | * For ld_imm64 no further tracking of precision | |
1569 | * into parent is necessary | |
1570 | */ | |
1571 | if (mode == BPF_IND || mode == BPF_ABS) | |
1572 | /* to be analyzed */ | |
1573 | return -ENOTSUPP; | |
b5dc0163 AS |
1574 | } |
1575 | return 0; | |
1576 | } | |
1577 | ||
1578 | /* the scalar precision tracking algorithm: | |
1579 | * . at the start all registers have precise=false. | |
1580 | * . scalar ranges are tracked as normal through alu and jmp insns. | |
1581 | * . once precise value of the scalar register is used in: | |
1582 | * . ptr + scalar alu | |
1583 | * . if (scalar cond K|scalar) | |
1584 | * . helper_call(.., scalar, ...) where ARG_CONST is expected | |
1585 | * backtrack through the verifier states and mark all registers and | |
1586 | * stack slots with spilled constants that these scalar regisers | |
1587 | * should be precise. | |
1588 | * . during state pruning two registers (or spilled stack slots) | |
1589 | * are equivalent if both are not precise. | |
1590 | * | |
1591 | * Note the verifier cannot simply walk register parentage chain, | |
1592 | * since many different registers and stack slots could have been | |
1593 | * used to compute single precise scalar. | |
1594 | * | |
1595 | * The approach of starting with precise=true for all registers and then | |
1596 | * backtrack to mark a register as not precise when the verifier detects | |
1597 | * that program doesn't care about specific value (e.g., when helper | |
1598 | * takes register as ARG_ANYTHING parameter) is not safe. | |
1599 | * | |
1600 | * It's ok to walk single parentage chain of the verifier states. | |
1601 | * It's possible that this backtracking will go all the way till 1st insn. | |
1602 | * All other branches will be explored for needing precision later. | |
1603 | * | |
1604 | * The backtracking needs to deal with cases like: | |
1605 | * 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) | |
1606 | * r9 -= r8 | |
1607 | * r5 = r9 | |
1608 | * if r5 > 0x79f goto pc+7 | |
1609 | * R5_w=inv(id=0,umax_value=1951,var_off=(0x0; 0x7ff)) | |
1610 | * r5 += 1 | |
1611 | * ... | |
1612 | * call bpf_perf_event_output#25 | |
1613 | * where .arg5_type = ARG_CONST_SIZE_OR_ZERO | |
1614 | * | |
1615 | * and this case: | |
1616 | * r6 = 1 | |
1617 | * call foo // uses callee's r6 inside to compute r0 | |
1618 | * r0 += r6 | |
1619 | * if r0 == 0 goto | |
1620 | * | |
1621 | * to track above reg_mask/stack_mask needs to be independent for each frame. | |
1622 | * | |
1623 | * Also if parent's curframe > frame where backtracking started, | |
1624 | * the verifier need to mark registers in both frames, otherwise callees | |
1625 | * may incorrectly prune callers. This is similar to | |
1626 | * commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences") | |
1627 | * | |
1628 | * For now backtracking falls back into conservative marking. | |
1629 | */ | |
1630 | static void mark_all_scalars_precise(struct bpf_verifier_env *env, | |
1631 | struct bpf_verifier_state *st) | |
1632 | { | |
1633 | struct bpf_func_state *func; | |
1634 | struct bpf_reg_state *reg; | |
1635 | int i, j; | |
1636 | ||
1637 | /* big hammer: mark all scalars precise in this path. | |
1638 | * pop_stack may still get !precise scalars. | |
1639 | */ | |
1640 | for (; st; st = st->parent) | |
1641 | for (i = 0; i <= st->curframe; i++) { | |
1642 | func = st->frame[i]; | |
1643 | for (j = 0; j < BPF_REG_FP; j++) { | |
1644 | reg = &func->regs[j]; | |
1645 | if (reg->type != SCALAR_VALUE) | |
1646 | continue; | |
1647 | reg->precise = true; | |
1648 | } | |
1649 | for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) { | |
1650 | if (func->stack[j].slot_type[0] != STACK_SPILL) | |
1651 | continue; | |
1652 | reg = &func->stack[j].spilled_ptr; | |
1653 | if (reg->type != SCALAR_VALUE) | |
1654 | continue; | |
1655 | reg->precise = true; | |
1656 | } | |
1657 | } | |
1658 | } | |
1659 | ||
a3ce685d AS |
1660 | static int __mark_chain_precision(struct bpf_verifier_env *env, int regno, |
1661 | int spi) | |
b5dc0163 AS |
1662 | { |
1663 | struct bpf_verifier_state *st = env->cur_state; | |
1664 | int first_idx = st->first_insn_idx; | |
1665 | int last_idx = env->insn_idx; | |
1666 | struct bpf_func_state *func; | |
1667 | struct bpf_reg_state *reg; | |
a3ce685d AS |
1668 | u32 reg_mask = regno >= 0 ? 1u << regno : 0; |
1669 | u64 stack_mask = spi >= 0 ? 1ull << spi : 0; | |
b5dc0163 | 1670 | bool skip_first = true; |
a3ce685d | 1671 | bool new_marks = false; |
b5dc0163 AS |
1672 | int i, err; |
1673 | ||
1674 | if (!env->allow_ptr_leaks) | |
1675 | /* backtracking is root only for now */ | |
1676 | return 0; | |
1677 | ||
1678 | func = st->frame[st->curframe]; | |
a3ce685d AS |
1679 | if (regno >= 0) { |
1680 | reg = &func->regs[regno]; | |
1681 | if (reg->type != SCALAR_VALUE) { | |
1682 | WARN_ONCE(1, "backtracing misuse"); | |
1683 | return -EFAULT; | |
1684 | } | |
1685 | if (!reg->precise) | |
1686 | new_marks = true; | |
1687 | else | |
1688 | reg_mask = 0; | |
1689 | reg->precise = true; | |
b5dc0163 | 1690 | } |
b5dc0163 | 1691 | |
a3ce685d AS |
1692 | while (spi >= 0) { |
1693 | if (func->stack[spi].slot_type[0] != STACK_SPILL) { | |
1694 | stack_mask = 0; | |
1695 | break; | |
1696 | } | |
1697 | reg = &func->stack[spi].spilled_ptr; | |
1698 | if (reg->type != SCALAR_VALUE) { | |
1699 | stack_mask = 0; | |
1700 | break; | |
1701 | } | |
1702 | if (!reg->precise) | |
1703 | new_marks = true; | |
1704 | else | |
1705 | stack_mask = 0; | |
1706 | reg->precise = true; | |
1707 | break; | |
1708 | } | |
1709 | ||
1710 | if (!new_marks) | |
1711 | return 0; | |
1712 | if (!reg_mask && !stack_mask) | |
1713 | return 0; | |
b5dc0163 AS |
1714 | for (;;) { |
1715 | DECLARE_BITMAP(mask, 64); | |
b5dc0163 AS |
1716 | u32 history = st->jmp_history_cnt; |
1717 | ||
1718 | if (env->log.level & BPF_LOG_LEVEL) | |
1719 | verbose(env, "last_idx %d first_idx %d\n", last_idx, first_idx); | |
1720 | for (i = last_idx;;) { | |
1721 | if (skip_first) { | |
1722 | err = 0; | |
1723 | skip_first = false; | |
1724 | } else { | |
1725 | err = backtrack_insn(env, i, ®_mask, &stack_mask); | |
1726 | } | |
1727 | if (err == -ENOTSUPP) { | |
1728 | mark_all_scalars_precise(env, st); | |
1729 | return 0; | |
1730 | } else if (err) { | |
1731 | return err; | |
1732 | } | |
1733 | if (!reg_mask && !stack_mask) | |
1734 | /* Found assignment(s) into tracked register in this state. | |
1735 | * Since this state is already marked, just return. | |
1736 | * Nothing to be tracked further in the parent state. | |
1737 | */ | |
1738 | return 0; | |
1739 | if (i == first_idx) | |
1740 | break; | |
1741 | i = get_prev_insn_idx(st, i, &history); | |
1742 | if (i >= env->prog->len) { | |
1743 | /* This can happen if backtracking reached insn 0 | |
1744 | * and there are still reg_mask or stack_mask | |
1745 | * to backtrack. | |
1746 | * It means the backtracking missed the spot where | |
1747 | * particular register was initialized with a constant. | |
1748 | */ | |
1749 | verbose(env, "BUG backtracking idx %d\n", i); | |
1750 | WARN_ONCE(1, "verifier backtracking bug"); | |
1751 | return -EFAULT; | |
1752 | } | |
1753 | } | |
1754 | st = st->parent; | |
1755 | if (!st) | |
1756 | break; | |
1757 | ||
a3ce685d | 1758 | new_marks = false; |
b5dc0163 AS |
1759 | func = st->frame[st->curframe]; |
1760 | bitmap_from_u64(mask, reg_mask); | |
1761 | for_each_set_bit(i, mask, 32) { | |
1762 | reg = &func->regs[i]; | |
a3ce685d AS |
1763 | if (reg->type != SCALAR_VALUE) { |
1764 | reg_mask &= ~(1u << i); | |
b5dc0163 | 1765 | continue; |
a3ce685d | 1766 | } |
b5dc0163 AS |
1767 | if (!reg->precise) |
1768 | new_marks = true; | |
1769 | reg->precise = true; | |
1770 | } | |
1771 | ||
1772 | bitmap_from_u64(mask, stack_mask); | |
1773 | for_each_set_bit(i, mask, 64) { | |
1774 | if (i >= func->allocated_stack / BPF_REG_SIZE) { | |
2339cd6c AS |
1775 | /* the sequence of instructions: |
1776 | * 2: (bf) r3 = r10 | |
1777 | * 3: (7b) *(u64 *)(r3 -8) = r0 | |
1778 | * 4: (79) r4 = *(u64 *)(r10 -8) | |
1779 | * doesn't contain jmps. It's backtracked | |
1780 | * as a single block. | |
1781 | * During backtracking insn 3 is not recognized as | |
1782 | * stack access, so at the end of backtracking | |
1783 | * stack slot fp-8 is still marked in stack_mask. | |
1784 | * However the parent state may not have accessed | |
1785 | * fp-8 and it's "unallocated" stack space. | |
1786 | * In such case fallback to conservative. | |
b5dc0163 | 1787 | */ |
2339cd6c AS |
1788 | mark_all_scalars_precise(env, st); |
1789 | return 0; | |
b5dc0163 AS |
1790 | } |
1791 | ||
a3ce685d AS |
1792 | if (func->stack[i].slot_type[0] != STACK_SPILL) { |
1793 | stack_mask &= ~(1ull << i); | |
b5dc0163 | 1794 | continue; |
a3ce685d | 1795 | } |
b5dc0163 | 1796 | reg = &func->stack[i].spilled_ptr; |
a3ce685d AS |
1797 | if (reg->type != SCALAR_VALUE) { |
1798 | stack_mask &= ~(1ull << i); | |
b5dc0163 | 1799 | continue; |
a3ce685d | 1800 | } |
b5dc0163 AS |
1801 | if (!reg->precise) |
1802 | new_marks = true; | |
1803 | reg->precise = true; | |
1804 | } | |
1805 | if (env->log.level & BPF_LOG_LEVEL) { | |
1806 | print_verifier_state(env, func); | |
1807 | verbose(env, "parent %s regs=%x stack=%llx marks\n", | |
1808 | new_marks ? "didn't have" : "already had", | |
1809 | reg_mask, stack_mask); | |
1810 | } | |
1811 | ||
a3ce685d AS |
1812 | if (!reg_mask && !stack_mask) |
1813 | break; | |
b5dc0163 AS |
1814 | if (!new_marks) |
1815 | break; | |
1816 | ||
1817 | last_idx = st->last_insn_idx; | |
1818 | first_idx = st->first_insn_idx; | |
1819 | } | |
1820 | return 0; | |
1821 | } | |
1822 | ||
a3ce685d AS |
1823 | static int mark_chain_precision(struct bpf_verifier_env *env, int regno) |
1824 | { | |
1825 | return __mark_chain_precision(env, regno, -1); | |
1826 | } | |
1827 | ||
1828 | static int mark_chain_precision_stack(struct bpf_verifier_env *env, int spi) | |
1829 | { | |
1830 | return __mark_chain_precision(env, -1, spi); | |
1831 | } | |
b5dc0163 | 1832 | |
1be7f75d AS |
1833 | static bool is_spillable_regtype(enum bpf_reg_type type) |
1834 | { | |
1835 | switch (type) { | |
1836 | case PTR_TO_MAP_VALUE: | |
1837 | case PTR_TO_MAP_VALUE_OR_NULL: | |
1838 | case PTR_TO_STACK: | |
1839 | case PTR_TO_CTX: | |
969bf05e | 1840 | case PTR_TO_PACKET: |
de8f3a83 | 1841 | case PTR_TO_PACKET_META: |
969bf05e | 1842 | case PTR_TO_PACKET_END: |
d58e468b | 1843 | case PTR_TO_FLOW_KEYS: |
1be7f75d | 1844 | case CONST_PTR_TO_MAP: |
c64b7983 JS |
1845 | case PTR_TO_SOCKET: |
1846 | case PTR_TO_SOCKET_OR_NULL: | |
46f8bc92 MKL |
1847 | case PTR_TO_SOCK_COMMON: |
1848 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
655a51e5 MKL |
1849 | case PTR_TO_TCP_SOCK: |
1850 | case PTR_TO_TCP_SOCK_OR_NULL: | |
fada7fdc | 1851 | case PTR_TO_XDP_SOCK: |
1be7f75d AS |
1852 | return true; |
1853 | default: | |
1854 | return false; | |
1855 | } | |
1856 | } | |
1857 | ||
cc2b14d5 AS |
1858 | /* Does this register contain a constant zero? */ |
1859 | static bool register_is_null(struct bpf_reg_state *reg) | |
1860 | { | |
1861 | return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0); | |
1862 | } | |
1863 | ||
f7cf25b2 AS |
1864 | static bool register_is_const(struct bpf_reg_state *reg) |
1865 | { | |
1866 | return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off); | |
1867 | } | |
1868 | ||
1869 | static void save_register_state(struct bpf_func_state *state, | |
1870 | int spi, struct bpf_reg_state *reg) | |
1871 | { | |
1872 | int i; | |
1873 | ||
1874 | state->stack[spi].spilled_ptr = *reg; | |
1875 | state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN; | |
1876 | ||
1877 | for (i = 0; i < BPF_REG_SIZE; i++) | |
1878 | state->stack[spi].slot_type[i] = STACK_SPILL; | |
1879 | } | |
1880 | ||
17a52670 AS |
1881 | /* check_stack_read/write functions track spill/fill of registers, |
1882 | * stack boundary and alignment are checked in check_mem_access() | |
1883 | */ | |
61bd5218 | 1884 | static int check_stack_write(struct bpf_verifier_env *env, |
f4d7e40a | 1885 | struct bpf_func_state *state, /* func where register points to */ |
af86ca4e | 1886 | int off, int size, int value_regno, int insn_idx) |
17a52670 | 1887 | { |
f4d7e40a | 1888 | struct bpf_func_state *cur; /* state of the current function */ |
638f5b90 | 1889 | int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err; |
b5dc0163 | 1890 | u32 dst_reg = env->prog->insnsi[insn_idx].dst_reg; |
f7cf25b2 | 1891 | struct bpf_reg_state *reg = NULL; |
638f5b90 | 1892 | |
f4d7e40a | 1893 | err = realloc_func_state(state, round_up(slot + 1, BPF_REG_SIZE), |
fd978bf7 | 1894 | state->acquired_refs, true); |
638f5b90 AS |
1895 | if (err) |
1896 | return err; | |
9c399760 AS |
1897 | /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0, |
1898 | * so it's aligned access and [off, off + size) are within stack limits | |
1899 | */ | |
638f5b90 AS |
1900 | if (!env->allow_ptr_leaks && |
1901 | state->stack[spi].slot_type[0] == STACK_SPILL && | |
1902 | size != BPF_REG_SIZE) { | |
1903 | verbose(env, "attempt to corrupt spilled pointer on stack\n"); | |
1904 | return -EACCES; | |
1905 | } | |
17a52670 | 1906 | |
f4d7e40a | 1907 | cur = env->cur_state->frame[env->cur_state->curframe]; |
f7cf25b2 AS |
1908 | if (value_regno >= 0) |
1909 | reg = &cur->regs[value_regno]; | |
17a52670 | 1910 | |
f7cf25b2 AS |
1911 | if (reg && size == BPF_REG_SIZE && register_is_const(reg) && |
1912 | !register_is_null(reg) && env->allow_ptr_leaks) { | |
b5dc0163 AS |
1913 | if (dst_reg != BPF_REG_FP) { |
1914 | /* The backtracking logic can only recognize explicit | |
1915 | * stack slot address like [fp - 8]. Other spill of | |
1916 | * scalar via different register has to be conervative. | |
1917 | * Backtrack from here and mark all registers as precise | |
1918 | * that contributed into 'reg' being a constant. | |
1919 | */ | |
1920 | err = mark_chain_precision(env, value_regno); | |
1921 | if (err) | |
1922 | return err; | |
1923 | } | |
f7cf25b2 AS |
1924 | save_register_state(state, spi, reg); |
1925 | } else if (reg && is_spillable_regtype(reg->type)) { | |
17a52670 | 1926 | /* register containing pointer is being spilled into stack */ |
9c399760 | 1927 | if (size != BPF_REG_SIZE) { |
f7cf25b2 | 1928 | verbose_linfo(env, insn_idx, "; "); |
61bd5218 | 1929 | verbose(env, "invalid size of register spill\n"); |
17a52670 AS |
1930 | return -EACCES; |
1931 | } | |
1932 | ||
f7cf25b2 | 1933 | if (state != cur && reg->type == PTR_TO_STACK) { |
f4d7e40a AS |
1934 | verbose(env, "cannot spill pointers to stack into stack frame of the caller\n"); |
1935 | return -EINVAL; | |
1936 | } | |
1937 | ||
f7cf25b2 AS |
1938 | if (!env->allow_ptr_leaks) { |
1939 | bool sanitize = false; | |
17a52670 | 1940 | |
f7cf25b2 AS |
1941 | if (state->stack[spi].slot_type[0] == STACK_SPILL && |
1942 | register_is_const(&state->stack[spi].spilled_ptr)) | |
1943 | sanitize = true; | |
1944 | for (i = 0; i < BPF_REG_SIZE; i++) | |
1945 | if (state->stack[spi].slot_type[i] == STACK_MISC) { | |
1946 | sanitize = true; | |
1947 | break; | |
1948 | } | |
1949 | if (sanitize) { | |
af86ca4e AS |
1950 | int *poff = &env->insn_aux_data[insn_idx].sanitize_stack_off; |
1951 | int soff = (-spi - 1) * BPF_REG_SIZE; | |
1952 | ||
1953 | /* detected reuse of integer stack slot with a pointer | |
1954 | * which means either llvm is reusing stack slot or | |
1955 | * an attacker is trying to exploit CVE-2018-3639 | |
1956 | * (speculative store bypass) | |
1957 | * Have to sanitize that slot with preemptive | |
1958 | * store of zero. | |
1959 | */ | |
1960 | if (*poff && *poff != soff) { | |
1961 | /* disallow programs where single insn stores | |
1962 | * into two different stack slots, since verifier | |
1963 | * cannot sanitize them | |
1964 | */ | |
1965 | verbose(env, | |
1966 | "insn %d cannot access two stack slots fp%d and fp%d", | |
1967 | insn_idx, *poff, soff); | |
1968 | return -EINVAL; | |
1969 | } | |
1970 | *poff = soff; | |
1971 | } | |
af86ca4e | 1972 | } |
f7cf25b2 | 1973 | save_register_state(state, spi, reg); |
9c399760 | 1974 | } else { |
cc2b14d5 AS |
1975 | u8 type = STACK_MISC; |
1976 | ||
679c782d EC |
1977 | /* regular write of data into stack destroys any spilled ptr */ |
1978 | state->stack[spi].spilled_ptr.type = NOT_INIT; | |
0bae2d4d JW |
1979 | /* Mark slots as STACK_MISC if they belonged to spilled ptr. */ |
1980 | if (state->stack[spi].slot_type[0] == STACK_SPILL) | |
1981 | for (i = 0; i < BPF_REG_SIZE; i++) | |
1982 | state->stack[spi].slot_type[i] = STACK_MISC; | |
9c399760 | 1983 | |
cc2b14d5 AS |
1984 | /* only mark the slot as written if all 8 bytes were written |
1985 | * otherwise read propagation may incorrectly stop too soon | |
1986 | * when stack slots are partially written. | |
1987 | * This heuristic means that read propagation will be | |
1988 | * conservative, since it will add reg_live_read marks | |
1989 | * to stack slots all the way to first state when programs | |
1990 | * writes+reads less than 8 bytes | |
1991 | */ | |
1992 | if (size == BPF_REG_SIZE) | |
1993 | state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN; | |
1994 | ||
1995 | /* when we zero initialize stack slots mark them as such */ | |
b5dc0163 AS |
1996 | if (reg && register_is_null(reg)) { |
1997 | /* backtracking doesn't work for STACK_ZERO yet. */ | |
1998 | err = mark_chain_precision(env, value_regno); | |
1999 | if (err) | |
2000 | return err; | |
cc2b14d5 | 2001 | type = STACK_ZERO; |
b5dc0163 | 2002 | } |
cc2b14d5 | 2003 | |
0bae2d4d | 2004 | /* Mark slots affected by this stack write. */ |
9c399760 | 2005 | for (i = 0; i < size; i++) |
638f5b90 | 2006 | state->stack[spi].slot_type[(slot - i) % BPF_REG_SIZE] = |
cc2b14d5 | 2007 | type; |
17a52670 AS |
2008 | } |
2009 | return 0; | |
2010 | } | |
2011 | ||
61bd5218 | 2012 | static int check_stack_read(struct bpf_verifier_env *env, |
f4d7e40a AS |
2013 | struct bpf_func_state *reg_state /* func where register points to */, |
2014 | int off, int size, int value_regno) | |
17a52670 | 2015 | { |
f4d7e40a AS |
2016 | struct bpf_verifier_state *vstate = env->cur_state; |
2017 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
638f5b90 | 2018 | int i, slot = -off - 1, spi = slot / BPF_REG_SIZE; |
f7cf25b2 | 2019 | struct bpf_reg_state *reg; |
638f5b90 | 2020 | u8 *stype; |
17a52670 | 2021 | |
f4d7e40a | 2022 | if (reg_state->allocated_stack <= slot) { |
638f5b90 AS |
2023 | verbose(env, "invalid read from stack off %d+0 size %d\n", |
2024 | off, size); | |
2025 | return -EACCES; | |
2026 | } | |
f4d7e40a | 2027 | stype = reg_state->stack[spi].slot_type; |
f7cf25b2 | 2028 | reg = ®_state->stack[spi].spilled_ptr; |
17a52670 | 2029 | |
638f5b90 | 2030 | if (stype[0] == STACK_SPILL) { |
9c399760 | 2031 | if (size != BPF_REG_SIZE) { |
f7cf25b2 AS |
2032 | if (reg->type != SCALAR_VALUE) { |
2033 | verbose_linfo(env, env->insn_idx, "; "); | |
2034 | verbose(env, "invalid size of register fill\n"); | |
2035 | return -EACCES; | |
2036 | } | |
2037 | if (value_regno >= 0) { | |
2038 | mark_reg_unknown(env, state->regs, value_regno); | |
2039 | state->regs[value_regno].live |= REG_LIVE_WRITTEN; | |
2040 | } | |
2041 | mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64); | |
2042 | return 0; | |
17a52670 | 2043 | } |
9c399760 | 2044 | for (i = 1; i < BPF_REG_SIZE; i++) { |
638f5b90 | 2045 | if (stype[(slot - i) % BPF_REG_SIZE] != STACK_SPILL) { |
61bd5218 | 2046 | verbose(env, "corrupted spill memory\n"); |
17a52670 AS |
2047 | return -EACCES; |
2048 | } | |
2049 | } | |
2050 | ||
dc503a8a | 2051 | if (value_regno >= 0) { |
17a52670 | 2052 | /* restore register state from stack */ |
f7cf25b2 | 2053 | state->regs[value_regno] = *reg; |
2f18f62e AS |
2054 | /* mark reg as written since spilled pointer state likely |
2055 | * has its liveness marks cleared by is_state_visited() | |
2056 | * which resets stack/reg liveness for state transitions | |
2057 | */ | |
2058 | state->regs[value_regno].live |= REG_LIVE_WRITTEN; | |
dc503a8a | 2059 | } |
f7cf25b2 | 2060 | mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64); |
17a52670 | 2061 | } else { |
cc2b14d5 AS |
2062 | int zeros = 0; |
2063 | ||
17a52670 | 2064 | for (i = 0; i < size; i++) { |
cc2b14d5 AS |
2065 | if (stype[(slot - i) % BPF_REG_SIZE] == STACK_MISC) |
2066 | continue; | |
2067 | if (stype[(slot - i) % BPF_REG_SIZE] == STACK_ZERO) { | |
2068 | zeros++; | |
2069 | continue; | |
17a52670 | 2070 | } |
cc2b14d5 AS |
2071 | verbose(env, "invalid read from stack off %d+%d size %d\n", |
2072 | off, i, size); | |
2073 | return -EACCES; | |
2074 | } | |
f7cf25b2 | 2075 | mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64); |
cc2b14d5 AS |
2076 | if (value_regno >= 0) { |
2077 | if (zeros == size) { | |
2078 | /* any size read into register is zero extended, | |
2079 | * so the whole register == const_zero | |
2080 | */ | |
2081 | __mark_reg_const_zero(&state->regs[value_regno]); | |
b5dc0163 AS |
2082 | /* backtracking doesn't support STACK_ZERO yet, |
2083 | * so mark it precise here, so that later | |
2084 | * backtracking can stop here. | |
2085 | * Backtracking may not need this if this register | |
2086 | * doesn't participate in pointer adjustment. | |
2087 | * Forward propagation of precise flag is not | |
2088 | * necessary either. This mark is only to stop | |
2089 | * backtracking. Any register that contributed | |
2090 | * to const 0 was marked precise before spill. | |
2091 | */ | |
2092 | state->regs[value_regno].precise = true; | |
cc2b14d5 AS |
2093 | } else { |
2094 | /* have read misc data from the stack */ | |
2095 | mark_reg_unknown(env, state->regs, value_regno); | |
2096 | } | |
2097 | state->regs[value_regno].live |= REG_LIVE_WRITTEN; | |
17a52670 | 2098 | } |
17a52670 | 2099 | } |
f7cf25b2 | 2100 | return 0; |
17a52670 AS |
2101 | } |
2102 | ||
e4298d25 DB |
2103 | static int check_stack_access(struct bpf_verifier_env *env, |
2104 | const struct bpf_reg_state *reg, | |
2105 | int off, int size) | |
2106 | { | |
2107 | /* Stack accesses must be at a fixed offset, so that we | |
2108 | * can determine what type of data were returned. See | |
2109 | * check_stack_read(). | |
2110 | */ | |
2111 | if (!tnum_is_const(reg->var_off)) { | |
2112 | char tn_buf[48]; | |
2113 | ||
2114 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
1fbd20f8 | 2115 | verbose(env, "variable stack access var_off=%s off=%d size=%d\n", |
e4298d25 DB |
2116 | tn_buf, off, size); |
2117 | return -EACCES; | |
2118 | } | |
2119 | ||
2120 | if (off >= 0 || off < -MAX_BPF_STACK) { | |
2121 | verbose(env, "invalid stack off=%d size=%d\n", off, size); | |
2122 | return -EACCES; | |
2123 | } | |
2124 | ||
2125 | return 0; | |
2126 | } | |
2127 | ||
591fe988 DB |
2128 | static int check_map_access_type(struct bpf_verifier_env *env, u32 regno, |
2129 | int off, int size, enum bpf_access_type type) | |
2130 | { | |
2131 | struct bpf_reg_state *regs = cur_regs(env); | |
2132 | struct bpf_map *map = regs[regno].map_ptr; | |
2133 | u32 cap = bpf_map_flags_to_cap(map); | |
2134 | ||
2135 | if (type == BPF_WRITE && !(cap & BPF_MAP_CAN_WRITE)) { | |
2136 | verbose(env, "write into map forbidden, value_size=%d off=%d size=%d\n", | |
2137 | map->value_size, off, size); | |
2138 | return -EACCES; | |
2139 | } | |
2140 | ||
2141 | if (type == BPF_READ && !(cap & BPF_MAP_CAN_READ)) { | |
2142 | verbose(env, "read from map forbidden, value_size=%d off=%d size=%d\n", | |
2143 | map->value_size, off, size); | |
2144 | return -EACCES; | |
2145 | } | |
2146 | ||
2147 | return 0; | |
2148 | } | |
2149 | ||
17a52670 | 2150 | /* check read/write into map element returned by bpf_map_lookup_elem() */ |
f1174f77 | 2151 | static int __check_map_access(struct bpf_verifier_env *env, u32 regno, int off, |
9fd29c08 | 2152 | int size, bool zero_size_allowed) |
17a52670 | 2153 | { |
638f5b90 AS |
2154 | struct bpf_reg_state *regs = cur_regs(env); |
2155 | struct bpf_map *map = regs[regno].map_ptr; | |
17a52670 | 2156 | |
9fd29c08 YS |
2157 | if (off < 0 || size < 0 || (size == 0 && !zero_size_allowed) || |
2158 | off + size > map->value_size) { | |
61bd5218 | 2159 | verbose(env, "invalid access to map value, value_size=%d off=%d size=%d\n", |
17a52670 AS |
2160 | map->value_size, off, size); |
2161 | return -EACCES; | |
2162 | } | |
2163 | return 0; | |
2164 | } | |
2165 | ||
f1174f77 EC |
2166 | /* check read/write into a map element with possible variable offset */ |
2167 | static int check_map_access(struct bpf_verifier_env *env, u32 regno, | |
9fd29c08 | 2168 | int off, int size, bool zero_size_allowed) |
dbcfe5f7 | 2169 | { |
f4d7e40a AS |
2170 | struct bpf_verifier_state *vstate = env->cur_state; |
2171 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
dbcfe5f7 GB |
2172 | struct bpf_reg_state *reg = &state->regs[regno]; |
2173 | int err; | |
2174 | ||
f1174f77 EC |
2175 | /* We may have adjusted the register to this map value, so we |
2176 | * need to try adding each of min_value and max_value to off | |
2177 | * to make sure our theoretical access will be safe. | |
dbcfe5f7 | 2178 | */ |
06ee7115 | 2179 | if (env->log.level & BPF_LOG_LEVEL) |
61bd5218 | 2180 | print_verifier_state(env, state); |
b7137c4e | 2181 | |
dbcfe5f7 GB |
2182 | /* The minimum value is only important with signed |
2183 | * comparisons where we can't assume the floor of a | |
2184 | * value is 0. If we are using signed variables for our | |
2185 | * index'es we need to make sure that whatever we use | |
2186 | * will have a set floor within our range. | |
2187 | */ | |
b7137c4e DB |
2188 | if (reg->smin_value < 0 && |
2189 | (reg->smin_value == S64_MIN || | |
2190 | (off + reg->smin_value != (s64)(s32)(off + reg->smin_value)) || | |
2191 | reg->smin_value + off < 0)) { | |
61bd5218 | 2192 | verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", |
dbcfe5f7 GB |
2193 | regno); |
2194 | return -EACCES; | |
2195 | } | |
9fd29c08 YS |
2196 | err = __check_map_access(env, regno, reg->smin_value + off, size, |
2197 | zero_size_allowed); | |
dbcfe5f7 | 2198 | if (err) { |
61bd5218 JK |
2199 | verbose(env, "R%d min value is outside of the array range\n", |
2200 | regno); | |
dbcfe5f7 GB |
2201 | return err; |
2202 | } | |
2203 | ||
b03c9f9f EC |
2204 | /* If we haven't set a max value then we need to bail since we can't be |
2205 | * sure we won't do bad things. | |
2206 | * If reg->umax_value + off could overflow, treat that as unbounded too. | |
dbcfe5f7 | 2207 | */ |
b03c9f9f | 2208 | if (reg->umax_value >= BPF_MAX_VAR_OFF) { |
61bd5218 | 2209 | verbose(env, "R%d unbounded memory access, make sure to bounds check any array access into a map\n", |
dbcfe5f7 GB |
2210 | regno); |
2211 | return -EACCES; | |
2212 | } | |
9fd29c08 YS |
2213 | err = __check_map_access(env, regno, reg->umax_value + off, size, |
2214 | zero_size_allowed); | |
f1174f77 | 2215 | if (err) |
61bd5218 JK |
2216 | verbose(env, "R%d max value is outside of the array range\n", |
2217 | regno); | |
d83525ca AS |
2218 | |
2219 | if (map_value_has_spin_lock(reg->map_ptr)) { | |
2220 | u32 lock = reg->map_ptr->spin_lock_off; | |
2221 | ||
2222 | /* if any part of struct bpf_spin_lock can be touched by | |
2223 | * load/store reject this program. | |
2224 | * To check that [x1, x2) overlaps with [y1, y2) | |
2225 | * it is sufficient to check x1 < y2 && y1 < x2. | |
2226 | */ | |
2227 | if (reg->smin_value + off < lock + sizeof(struct bpf_spin_lock) && | |
2228 | lock < reg->umax_value + off + size) { | |
2229 | verbose(env, "bpf_spin_lock cannot be accessed directly by load/store\n"); | |
2230 | return -EACCES; | |
2231 | } | |
2232 | } | |
f1174f77 | 2233 | return err; |
dbcfe5f7 GB |
2234 | } |
2235 | ||
969bf05e AS |
2236 | #define MAX_PACKET_OFF 0xffff |
2237 | ||
58e2af8b | 2238 | static bool may_access_direct_pkt_data(struct bpf_verifier_env *env, |
3a0af8fd TG |
2239 | const struct bpf_call_arg_meta *meta, |
2240 | enum bpf_access_type t) | |
4acf6c0b | 2241 | { |
36bbef52 | 2242 | switch (env->prog->type) { |
5d66fa7d | 2243 | /* Program types only with direct read access go here! */ |
3a0af8fd TG |
2244 | case BPF_PROG_TYPE_LWT_IN: |
2245 | case BPF_PROG_TYPE_LWT_OUT: | |
004d4b27 | 2246 | case BPF_PROG_TYPE_LWT_SEG6LOCAL: |
2dbb9b9e | 2247 | case BPF_PROG_TYPE_SK_REUSEPORT: |
5d66fa7d | 2248 | case BPF_PROG_TYPE_FLOW_DISSECTOR: |
d5563d36 | 2249 | case BPF_PROG_TYPE_CGROUP_SKB: |
3a0af8fd TG |
2250 | if (t == BPF_WRITE) |
2251 | return false; | |
7e57fbb2 | 2252 | /* fallthrough */ |
5d66fa7d DB |
2253 | |
2254 | /* Program types with direct read + write access go here! */ | |
36bbef52 DB |
2255 | case BPF_PROG_TYPE_SCHED_CLS: |
2256 | case BPF_PROG_TYPE_SCHED_ACT: | |
4acf6c0b | 2257 | case BPF_PROG_TYPE_XDP: |
3a0af8fd | 2258 | case BPF_PROG_TYPE_LWT_XMIT: |
8a31db56 | 2259 | case BPF_PROG_TYPE_SK_SKB: |
4f738adb | 2260 | case BPF_PROG_TYPE_SK_MSG: |
36bbef52 DB |
2261 | if (meta) |
2262 | return meta->pkt_access; | |
2263 | ||
2264 | env->seen_direct_write = true; | |
4acf6c0b | 2265 | return true; |
0d01da6a SF |
2266 | |
2267 | case BPF_PROG_TYPE_CGROUP_SOCKOPT: | |
2268 | if (t == BPF_WRITE) | |
2269 | env->seen_direct_write = true; | |
2270 | ||
2271 | return true; | |
2272 | ||
4acf6c0b BB |
2273 | default: |
2274 | return false; | |
2275 | } | |
2276 | } | |
2277 | ||
f1174f77 | 2278 | static int __check_packet_access(struct bpf_verifier_env *env, u32 regno, |
9fd29c08 | 2279 | int off, int size, bool zero_size_allowed) |
969bf05e | 2280 | { |
638f5b90 | 2281 | struct bpf_reg_state *regs = cur_regs(env); |
58e2af8b | 2282 | struct bpf_reg_state *reg = ®s[regno]; |
969bf05e | 2283 | |
9fd29c08 YS |
2284 | if (off < 0 || size < 0 || (size == 0 && !zero_size_allowed) || |
2285 | (u64)off + size > reg->range) { | |
61bd5218 | 2286 | verbose(env, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n", |
d91b28ed | 2287 | off, size, regno, reg->id, reg->off, reg->range); |
969bf05e AS |
2288 | return -EACCES; |
2289 | } | |
2290 | return 0; | |
2291 | } | |
2292 | ||
f1174f77 | 2293 | static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, |
9fd29c08 | 2294 | int size, bool zero_size_allowed) |
f1174f77 | 2295 | { |
638f5b90 | 2296 | struct bpf_reg_state *regs = cur_regs(env); |
f1174f77 EC |
2297 | struct bpf_reg_state *reg = ®s[regno]; |
2298 | int err; | |
2299 | ||
2300 | /* We may have added a variable offset to the packet pointer; but any | |
2301 | * reg->range we have comes after that. We are only checking the fixed | |
2302 | * offset. | |
2303 | */ | |
2304 | ||
2305 | /* We don't allow negative numbers, because we aren't tracking enough | |
2306 | * detail to prove they're safe. | |
2307 | */ | |
b03c9f9f | 2308 | if (reg->smin_value < 0) { |
61bd5218 | 2309 | verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", |
f1174f77 EC |
2310 | regno); |
2311 | return -EACCES; | |
2312 | } | |
9fd29c08 | 2313 | err = __check_packet_access(env, regno, off, size, zero_size_allowed); |
f1174f77 | 2314 | if (err) { |
61bd5218 | 2315 | verbose(env, "R%d offset is outside of the packet\n", regno); |
f1174f77 EC |
2316 | return err; |
2317 | } | |
e647815a JW |
2318 | |
2319 | /* __check_packet_access has made sure "off + size - 1" is within u16. | |
2320 | * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff, | |
2321 | * otherwise find_good_pkt_pointers would have refused to set range info | |
2322 | * that __check_packet_access would have rejected this pkt access. | |
2323 | * Therefore, "off + reg->umax_value + size - 1" won't overflow u32. | |
2324 | */ | |
2325 | env->prog->aux->max_pkt_offset = | |
2326 | max_t(u32, env->prog->aux->max_pkt_offset, | |
2327 | off + reg->umax_value + size - 1); | |
2328 | ||
f1174f77 EC |
2329 | return err; |
2330 | } | |
2331 | ||
2332 | /* check access to 'struct bpf_context' fields. Supports fixed offsets only */ | |
31fd8581 | 2333 | static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size, |
19de99f7 | 2334 | enum bpf_access_type t, enum bpf_reg_type *reg_type) |
17a52670 | 2335 | { |
f96da094 DB |
2336 | struct bpf_insn_access_aux info = { |
2337 | .reg_type = *reg_type, | |
2338 | }; | |
31fd8581 | 2339 | |
4f9218aa | 2340 | if (env->ops->is_valid_access && |
5e43f899 | 2341 | env->ops->is_valid_access(off, size, t, env->prog, &info)) { |
f96da094 DB |
2342 | /* A non zero info.ctx_field_size indicates that this field is a |
2343 | * candidate for later verifier transformation to load the whole | |
2344 | * field and then apply a mask when accessed with a narrower | |
2345 | * access than actual ctx access size. A zero info.ctx_field_size | |
2346 | * will only allow for whole field access and rejects any other | |
2347 | * type of narrower access. | |
31fd8581 | 2348 | */ |
23994631 | 2349 | *reg_type = info.reg_type; |
31fd8581 | 2350 | |
4f9218aa | 2351 | env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size; |
32bbe007 AS |
2352 | /* remember the offset of last byte accessed in ctx */ |
2353 | if (env->prog->aux->max_ctx_offset < off + size) | |
2354 | env->prog->aux->max_ctx_offset = off + size; | |
17a52670 | 2355 | return 0; |
32bbe007 | 2356 | } |
17a52670 | 2357 | |
61bd5218 | 2358 | verbose(env, "invalid bpf_context access off=%d size=%d\n", off, size); |
17a52670 AS |
2359 | return -EACCES; |
2360 | } | |
2361 | ||
d58e468b PP |
2362 | static int check_flow_keys_access(struct bpf_verifier_env *env, int off, |
2363 | int size) | |
2364 | { | |
2365 | if (size < 0 || off < 0 || | |
2366 | (u64)off + size > sizeof(struct bpf_flow_keys)) { | |
2367 | verbose(env, "invalid access to flow keys off=%d size=%d\n", | |
2368 | off, size); | |
2369 | return -EACCES; | |
2370 | } | |
2371 | return 0; | |
2372 | } | |
2373 | ||
5f456649 MKL |
2374 | static int check_sock_access(struct bpf_verifier_env *env, int insn_idx, |
2375 | u32 regno, int off, int size, | |
2376 | enum bpf_access_type t) | |
c64b7983 JS |
2377 | { |
2378 | struct bpf_reg_state *regs = cur_regs(env); | |
2379 | struct bpf_reg_state *reg = ®s[regno]; | |
5f456649 | 2380 | struct bpf_insn_access_aux info = {}; |
46f8bc92 | 2381 | bool valid; |
c64b7983 JS |
2382 | |
2383 | if (reg->smin_value < 0) { | |
2384 | verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", | |
2385 | regno); | |
2386 | return -EACCES; | |
2387 | } | |
2388 | ||
46f8bc92 MKL |
2389 | switch (reg->type) { |
2390 | case PTR_TO_SOCK_COMMON: | |
2391 | valid = bpf_sock_common_is_valid_access(off, size, t, &info); | |
2392 | break; | |
2393 | case PTR_TO_SOCKET: | |
2394 | valid = bpf_sock_is_valid_access(off, size, t, &info); | |
2395 | break; | |
655a51e5 MKL |
2396 | case PTR_TO_TCP_SOCK: |
2397 | valid = bpf_tcp_sock_is_valid_access(off, size, t, &info); | |
2398 | break; | |
fada7fdc JL |
2399 | case PTR_TO_XDP_SOCK: |
2400 | valid = bpf_xdp_sock_is_valid_access(off, size, t, &info); | |
2401 | break; | |
46f8bc92 MKL |
2402 | default: |
2403 | valid = false; | |
c64b7983 JS |
2404 | } |
2405 | ||
5f456649 | 2406 | |
46f8bc92 MKL |
2407 | if (valid) { |
2408 | env->insn_aux_data[insn_idx].ctx_field_size = | |
2409 | info.ctx_field_size; | |
2410 | return 0; | |
2411 | } | |
2412 | ||
2413 | verbose(env, "R%d invalid %s access off=%d size=%d\n", | |
2414 | regno, reg_type_str[reg->type], off, size); | |
2415 | ||
2416 | return -EACCES; | |
c64b7983 JS |
2417 | } |
2418 | ||
4cabc5b1 DB |
2419 | static bool __is_pointer_value(bool allow_ptr_leaks, |
2420 | const struct bpf_reg_state *reg) | |
1be7f75d | 2421 | { |
4cabc5b1 | 2422 | if (allow_ptr_leaks) |
1be7f75d AS |
2423 | return false; |
2424 | ||
f1174f77 | 2425 | return reg->type != SCALAR_VALUE; |
1be7f75d AS |
2426 | } |
2427 | ||
2a159c6f DB |
2428 | static struct bpf_reg_state *reg_state(struct bpf_verifier_env *env, int regno) |
2429 | { | |
2430 | return cur_regs(env) + regno; | |
2431 | } | |
2432 | ||
4cabc5b1 DB |
2433 | static bool is_pointer_value(struct bpf_verifier_env *env, int regno) |
2434 | { | |
2a159c6f | 2435 | return __is_pointer_value(env->allow_ptr_leaks, reg_state(env, regno)); |
4cabc5b1 DB |
2436 | } |
2437 | ||
f37a8cb8 DB |
2438 | static bool is_ctx_reg(struct bpf_verifier_env *env, int regno) |
2439 | { | |
2a159c6f | 2440 | const struct bpf_reg_state *reg = reg_state(env, regno); |
f37a8cb8 | 2441 | |
46f8bc92 MKL |
2442 | return reg->type == PTR_TO_CTX; |
2443 | } | |
2444 | ||
2445 | static bool is_sk_reg(struct bpf_verifier_env *env, int regno) | |
2446 | { | |
2447 | const struct bpf_reg_state *reg = reg_state(env, regno); | |
2448 | ||
2449 | return type_is_sk_pointer(reg->type); | |
f37a8cb8 DB |
2450 | } |
2451 | ||
ca369602 DB |
2452 | static bool is_pkt_reg(struct bpf_verifier_env *env, int regno) |
2453 | { | |
2a159c6f | 2454 | const struct bpf_reg_state *reg = reg_state(env, regno); |
ca369602 DB |
2455 | |
2456 | return type_is_pkt_pointer(reg->type); | |
2457 | } | |
2458 | ||
4b5defde DB |
2459 | static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno) |
2460 | { | |
2461 | const struct bpf_reg_state *reg = reg_state(env, regno); | |
2462 | ||
2463 | /* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */ | |
2464 | return reg->type == PTR_TO_FLOW_KEYS; | |
2465 | } | |
2466 | ||
61bd5218 JK |
2467 | static int check_pkt_ptr_alignment(struct bpf_verifier_env *env, |
2468 | const struct bpf_reg_state *reg, | |
d1174416 | 2469 | int off, int size, bool strict) |
969bf05e | 2470 | { |
f1174f77 | 2471 | struct tnum reg_off; |
e07b98d9 | 2472 | int ip_align; |
d1174416 DM |
2473 | |
2474 | /* Byte size accesses are always allowed. */ | |
2475 | if (!strict || size == 1) | |
2476 | return 0; | |
2477 | ||
e4eda884 DM |
2478 | /* For platforms that do not have a Kconfig enabling |
2479 | * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of | |
2480 | * NET_IP_ALIGN is universally set to '2'. And on platforms | |
2481 | * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get | |
2482 | * to this code only in strict mode where we want to emulate | |
2483 | * the NET_IP_ALIGN==2 checking. Therefore use an | |
2484 | * unconditional IP align value of '2'. | |
e07b98d9 | 2485 | */ |
e4eda884 | 2486 | ip_align = 2; |
f1174f77 EC |
2487 | |
2488 | reg_off = tnum_add(reg->var_off, tnum_const(ip_align + reg->off + off)); | |
2489 | if (!tnum_is_aligned(reg_off, size)) { | |
2490 | char tn_buf[48]; | |
2491 | ||
2492 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
61bd5218 JK |
2493 | verbose(env, |
2494 | "misaligned packet access off %d+%s+%d+%d size %d\n", | |
f1174f77 | 2495 | ip_align, tn_buf, reg->off, off, size); |
969bf05e AS |
2496 | return -EACCES; |
2497 | } | |
79adffcd | 2498 | |
969bf05e AS |
2499 | return 0; |
2500 | } | |
2501 | ||
61bd5218 JK |
2502 | static int check_generic_ptr_alignment(struct bpf_verifier_env *env, |
2503 | const struct bpf_reg_state *reg, | |
f1174f77 EC |
2504 | const char *pointer_desc, |
2505 | int off, int size, bool strict) | |
79adffcd | 2506 | { |
f1174f77 EC |
2507 | struct tnum reg_off; |
2508 | ||
2509 | /* Byte size accesses are always allowed. */ | |
2510 | if (!strict || size == 1) | |
2511 | return 0; | |
2512 | ||
2513 | reg_off = tnum_add(reg->var_off, tnum_const(reg->off + off)); | |
2514 | if (!tnum_is_aligned(reg_off, size)) { | |
2515 | char tn_buf[48]; | |
2516 | ||
2517 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
61bd5218 | 2518 | verbose(env, "misaligned %saccess off %s+%d+%d size %d\n", |
f1174f77 | 2519 | pointer_desc, tn_buf, reg->off, off, size); |
79adffcd DB |
2520 | return -EACCES; |
2521 | } | |
2522 | ||
969bf05e AS |
2523 | return 0; |
2524 | } | |
2525 | ||
e07b98d9 | 2526 | static int check_ptr_alignment(struct bpf_verifier_env *env, |
ca369602 DB |
2527 | const struct bpf_reg_state *reg, int off, |
2528 | int size, bool strict_alignment_once) | |
79adffcd | 2529 | { |
ca369602 | 2530 | bool strict = env->strict_alignment || strict_alignment_once; |
f1174f77 | 2531 | const char *pointer_desc = ""; |
d1174416 | 2532 | |
79adffcd DB |
2533 | switch (reg->type) { |
2534 | case PTR_TO_PACKET: | |
de8f3a83 DB |
2535 | case PTR_TO_PACKET_META: |
2536 | /* Special case, because of NET_IP_ALIGN. Given metadata sits | |
2537 | * right in front, treat it the very same way. | |
2538 | */ | |
61bd5218 | 2539 | return check_pkt_ptr_alignment(env, reg, off, size, strict); |
d58e468b PP |
2540 | case PTR_TO_FLOW_KEYS: |
2541 | pointer_desc = "flow keys "; | |
2542 | break; | |
f1174f77 EC |
2543 | case PTR_TO_MAP_VALUE: |
2544 | pointer_desc = "value "; | |
2545 | break; | |
2546 | case PTR_TO_CTX: | |
2547 | pointer_desc = "context "; | |
2548 | break; | |
2549 | case PTR_TO_STACK: | |
2550 | pointer_desc = "stack "; | |
a5ec6ae1 JH |
2551 | /* The stack spill tracking logic in check_stack_write() |
2552 | * and check_stack_read() relies on stack accesses being | |
2553 | * aligned. | |
2554 | */ | |
2555 | strict = true; | |
f1174f77 | 2556 | break; |
c64b7983 JS |
2557 | case PTR_TO_SOCKET: |
2558 | pointer_desc = "sock "; | |
2559 | break; | |
46f8bc92 MKL |
2560 | case PTR_TO_SOCK_COMMON: |
2561 | pointer_desc = "sock_common "; | |
2562 | break; | |
655a51e5 MKL |
2563 | case PTR_TO_TCP_SOCK: |
2564 | pointer_desc = "tcp_sock "; | |
2565 | break; | |
fada7fdc JL |
2566 | case PTR_TO_XDP_SOCK: |
2567 | pointer_desc = "xdp_sock "; | |
2568 | break; | |
79adffcd | 2569 | default: |
f1174f77 | 2570 | break; |
79adffcd | 2571 | } |
61bd5218 JK |
2572 | return check_generic_ptr_alignment(env, reg, pointer_desc, off, size, |
2573 | strict); | |
79adffcd DB |
2574 | } |
2575 | ||
f4d7e40a AS |
2576 | static int update_stack_depth(struct bpf_verifier_env *env, |
2577 | const struct bpf_func_state *func, | |
2578 | int off) | |
2579 | { | |
9c8105bd | 2580 | u16 stack = env->subprog_info[func->subprogno].stack_depth; |
f4d7e40a AS |
2581 | |
2582 | if (stack >= -off) | |
2583 | return 0; | |
2584 | ||
2585 | /* update known max for given subprogram */ | |
9c8105bd | 2586 | env->subprog_info[func->subprogno].stack_depth = -off; |
70a87ffe AS |
2587 | return 0; |
2588 | } | |
f4d7e40a | 2589 | |
70a87ffe AS |
2590 | /* starting from main bpf function walk all instructions of the function |
2591 | * and recursively walk all callees that given function can call. | |
2592 | * Ignore jump and exit insns. | |
2593 | * Since recursion is prevented by check_cfg() this algorithm | |
2594 | * only needs a local stack of MAX_CALL_FRAMES to remember callsites | |
2595 | */ | |
2596 | static int check_max_stack_depth(struct bpf_verifier_env *env) | |
2597 | { | |
9c8105bd JW |
2598 | int depth = 0, frame = 0, idx = 0, i = 0, subprog_end; |
2599 | struct bpf_subprog_info *subprog = env->subprog_info; | |
70a87ffe | 2600 | struct bpf_insn *insn = env->prog->insnsi; |
70a87ffe AS |
2601 | int ret_insn[MAX_CALL_FRAMES]; |
2602 | int ret_prog[MAX_CALL_FRAMES]; | |
f4d7e40a | 2603 | |
70a87ffe AS |
2604 | process_func: |
2605 | /* round up to 32-bytes, since this is granularity | |
2606 | * of interpreter stack size | |
2607 | */ | |
9c8105bd | 2608 | depth += round_up(max_t(u32, subprog[idx].stack_depth, 1), 32); |
70a87ffe | 2609 | if (depth > MAX_BPF_STACK) { |
f4d7e40a | 2610 | verbose(env, "combined stack size of %d calls is %d. Too large\n", |
70a87ffe | 2611 | frame + 1, depth); |
f4d7e40a AS |
2612 | return -EACCES; |
2613 | } | |
70a87ffe | 2614 | continue_func: |
4cb3d99c | 2615 | subprog_end = subprog[idx + 1].start; |
70a87ffe AS |
2616 | for (; i < subprog_end; i++) { |
2617 | if (insn[i].code != (BPF_JMP | BPF_CALL)) | |
2618 | continue; | |
2619 | if (insn[i].src_reg != BPF_PSEUDO_CALL) | |
2620 | continue; | |
2621 | /* remember insn and function to return to */ | |
2622 | ret_insn[frame] = i + 1; | |
9c8105bd | 2623 | ret_prog[frame] = idx; |
70a87ffe AS |
2624 | |
2625 | /* find the callee */ | |
2626 | i = i + insn[i].imm + 1; | |
9c8105bd JW |
2627 | idx = find_subprog(env, i); |
2628 | if (idx < 0) { | |
70a87ffe AS |
2629 | WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", |
2630 | i); | |
2631 | return -EFAULT; | |
2632 | } | |
70a87ffe AS |
2633 | frame++; |
2634 | if (frame >= MAX_CALL_FRAMES) { | |
927cb781 PC |
2635 | verbose(env, "the call stack of %d frames is too deep !\n", |
2636 | frame); | |
2637 | return -E2BIG; | |
70a87ffe AS |
2638 | } |
2639 | goto process_func; | |
2640 | } | |
2641 | /* end of for() loop means the last insn of the 'subprog' | |
2642 | * was reached. Doesn't matter whether it was JA or EXIT | |
2643 | */ | |
2644 | if (frame == 0) | |
2645 | return 0; | |
9c8105bd | 2646 | depth -= round_up(max_t(u32, subprog[idx].stack_depth, 1), 32); |
70a87ffe AS |
2647 | frame--; |
2648 | i = ret_insn[frame]; | |
9c8105bd | 2649 | idx = ret_prog[frame]; |
70a87ffe | 2650 | goto continue_func; |
f4d7e40a AS |
2651 | } |
2652 | ||
19d28fbd | 2653 | #ifndef CONFIG_BPF_JIT_ALWAYS_ON |
1ea47e01 AS |
2654 | static int get_callee_stack_depth(struct bpf_verifier_env *env, |
2655 | const struct bpf_insn *insn, int idx) | |
2656 | { | |
2657 | int start = idx + insn->imm + 1, subprog; | |
2658 | ||
2659 | subprog = find_subprog(env, start); | |
2660 | if (subprog < 0) { | |
2661 | WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", | |
2662 | start); | |
2663 | return -EFAULT; | |
2664 | } | |
9c8105bd | 2665 | return env->subprog_info[subprog].stack_depth; |
1ea47e01 | 2666 | } |
19d28fbd | 2667 | #endif |
1ea47e01 | 2668 | |
58990d1f DB |
2669 | static int check_ctx_reg(struct bpf_verifier_env *env, |
2670 | const struct bpf_reg_state *reg, int regno) | |
2671 | { | |
2672 | /* Access to ctx or passing it to a helper is only allowed in | |
2673 | * its original, unmodified form. | |
2674 | */ | |
2675 | ||
2676 | if (reg->off) { | |
2677 | verbose(env, "dereference of modified ctx ptr R%d off=%d disallowed\n", | |
2678 | regno, reg->off); | |
2679 | return -EACCES; | |
2680 | } | |
2681 | ||
2682 | if (!tnum_is_const(reg->var_off) || reg->var_off.value) { | |
2683 | char tn_buf[48]; | |
2684 | ||
2685 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
2686 | verbose(env, "variable ctx access var_off=%s disallowed\n", tn_buf); | |
2687 | return -EACCES; | |
2688 | } | |
2689 | ||
2690 | return 0; | |
2691 | } | |
2692 | ||
9df1c28b MM |
2693 | static int check_tp_buffer_access(struct bpf_verifier_env *env, |
2694 | const struct bpf_reg_state *reg, | |
2695 | int regno, int off, int size) | |
2696 | { | |
2697 | if (off < 0) { | |
2698 | verbose(env, | |
2699 | "R%d invalid tracepoint buffer access: off=%d, size=%d", | |
2700 | regno, off, size); | |
2701 | return -EACCES; | |
2702 | } | |
2703 | if (!tnum_is_const(reg->var_off) || reg->var_off.value) { | |
2704 | char tn_buf[48]; | |
2705 | ||
2706 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
2707 | verbose(env, | |
2708 | "R%d invalid variable buffer offset: off=%d, var_off=%s", | |
2709 | regno, off, tn_buf); | |
2710 | return -EACCES; | |
2711 | } | |
2712 | if (off + size > env->prog->aux->max_tp_access) | |
2713 | env->prog->aux->max_tp_access = off + size; | |
2714 | ||
2715 | return 0; | |
2716 | } | |
2717 | ||
2718 | ||
0c17d1d2 JH |
2719 | /* truncate register to smaller size (in bytes) |
2720 | * must be called with size < BPF_REG_SIZE | |
2721 | */ | |
2722 | static void coerce_reg_to_size(struct bpf_reg_state *reg, int size) | |
2723 | { | |
2724 | u64 mask; | |
2725 | ||
2726 | /* clear high bits in bit representation */ | |
2727 | reg->var_off = tnum_cast(reg->var_off, size); | |
2728 | ||
2729 | /* fix arithmetic bounds */ | |
2730 | mask = ((u64)1 << (size * 8)) - 1; | |
2731 | if ((reg->umin_value & ~mask) == (reg->umax_value & ~mask)) { | |
2732 | reg->umin_value &= mask; | |
2733 | reg->umax_value &= mask; | |
2734 | } else { | |
2735 | reg->umin_value = 0; | |
2736 | reg->umax_value = mask; | |
2737 | } | |
2738 | reg->smin_value = reg->umin_value; | |
2739 | reg->smax_value = reg->umax_value; | |
2740 | } | |
2741 | ||
17a52670 AS |
2742 | /* check whether memory at (regno + off) is accessible for t = (read | write) |
2743 | * if t==write, value_regno is a register which value is stored into memory | |
2744 | * if t==read, value_regno is a register which will receive the value from memory | |
2745 | * if t==write && value_regno==-1, some unknown value is stored into memory | |
2746 | * if t==read && value_regno==-1, don't care what we read from memory | |
2747 | */ | |
ca369602 DB |
2748 | static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno, |
2749 | int off, int bpf_size, enum bpf_access_type t, | |
2750 | int value_regno, bool strict_alignment_once) | |
17a52670 | 2751 | { |
638f5b90 AS |
2752 | struct bpf_reg_state *regs = cur_regs(env); |
2753 | struct bpf_reg_state *reg = regs + regno; | |
f4d7e40a | 2754 | struct bpf_func_state *state; |
17a52670 AS |
2755 | int size, err = 0; |
2756 | ||
2757 | size = bpf_size_to_bytes(bpf_size); | |
2758 | if (size < 0) | |
2759 | return size; | |
2760 | ||
f1174f77 | 2761 | /* alignment checks will add in reg->off themselves */ |
ca369602 | 2762 | err = check_ptr_alignment(env, reg, off, size, strict_alignment_once); |
969bf05e AS |
2763 | if (err) |
2764 | return err; | |
17a52670 | 2765 | |
f1174f77 EC |
2766 | /* for access checks, reg->off is just part of off */ |
2767 | off += reg->off; | |
2768 | ||
2769 | if (reg->type == PTR_TO_MAP_VALUE) { | |
1be7f75d AS |
2770 | if (t == BPF_WRITE && value_regno >= 0 && |
2771 | is_pointer_value(env, value_regno)) { | |
61bd5218 | 2772 | verbose(env, "R%d leaks addr into map\n", value_regno); |
1be7f75d AS |
2773 | return -EACCES; |
2774 | } | |
591fe988 DB |
2775 | err = check_map_access_type(env, regno, off, size, t); |
2776 | if (err) | |
2777 | return err; | |
9fd29c08 | 2778 | err = check_map_access(env, regno, off, size, false); |
17a52670 | 2779 | if (!err && t == BPF_READ && value_regno >= 0) |
638f5b90 | 2780 | mark_reg_unknown(env, regs, value_regno); |
17a52670 | 2781 | |
1a0dc1ac | 2782 | } else if (reg->type == PTR_TO_CTX) { |
f1174f77 | 2783 | enum bpf_reg_type reg_type = SCALAR_VALUE; |
19de99f7 | 2784 | |
1be7f75d AS |
2785 | if (t == BPF_WRITE && value_regno >= 0 && |
2786 | is_pointer_value(env, value_regno)) { | |
61bd5218 | 2787 | verbose(env, "R%d leaks addr into ctx\n", value_regno); |
1be7f75d AS |
2788 | return -EACCES; |
2789 | } | |
f1174f77 | 2790 | |
58990d1f DB |
2791 | err = check_ctx_reg(env, reg, regno); |
2792 | if (err < 0) | |
2793 | return err; | |
2794 | ||
31fd8581 | 2795 | err = check_ctx_access(env, insn_idx, off, size, t, ®_type); |
969bf05e | 2796 | if (!err && t == BPF_READ && value_regno >= 0) { |
f1174f77 | 2797 | /* ctx access returns either a scalar, or a |
de8f3a83 DB |
2798 | * PTR_TO_PACKET[_META,_END]. In the latter |
2799 | * case, we know the offset is zero. | |
f1174f77 | 2800 | */ |
46f8bc92 | 2801 | if (reg_type == SCALAR_VALUE) { |
638f5b90 | 2802 | mark_reg_unknown(env, regs, value_regno); |
46f8bc92 | 2803 | } else { |
638f5b90 | 2804 | mark_reg_known_zero(env, regs, |
61bd5218 | 2805 | value_regno); |
46f8bc92 MKL |
2806 | if (reg_type_may_be_null(reg_type)) |
2807 | regs[value_regno].id = ++env->id_gen; | |
5327ed3d JW |
2808 | /* A load of ctx field could have different |
2809 | * actual load size with the one encoded in the | |
2810 | * insn. When the dst is PTR, it is for sure not | |
2811 | * a sub-register. | |
2812 | */ | |
2813 | regs[value_regno].subreg_def = DEF_NOT_SUBREG; | |
46f8bc92 | 2814 | } |
638f5b90 | 2815 | regs[value_regno].type = reg_type; |
969bf05e | 2816 | } |
17a52670 | 2817 | |
f1174f77 | 2818 | } else if (reg->type == PTR_TO_STACK) { |
f1174f77 | 2819 | off += reg->var_off.value; |
e4298d25 DB |
2820 | err = check_stack_access(env, reg, off, size); |
2821 | if (err) | |
2822 | return err; | |
8726679a | 2823 | |
f4d7e40a AS |
2824 | state = func(env, reg); |
2825 | err = update_stack_depth(env, state, off); | |
2826 | if (err) | |
2827 | return err; | |
8726679a | 2828 | |
638f5b90 | 2829 | if (t == BPF_WRITE) |
61bd5218 | 2830 | err = check_stack_write(env, state, off, size, |
af86ca4e | 2831 | value_regno, insn_idx); |
638f5b90 | 2832 | else |
61bd5218 JK |
2833 | err = check_stack_read(env, state, off, size, |
2834 | value_regno); | |
de8f3a83 | 2835 | } else if (reg_is_pkt_pointer(reg)) { |
3a0af8fd | 2836 | if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) { |
61bd5218 | 2837 | verbose(env, "cannot write into packet\n"); |
969bf05e AS |
2838 | return -EACCES; |
2839 | } | |
4acf6c0b BB |
2840 | if (t == BPF_WRITE && value_regno >= 0 && |
2841 | is_pointer_value(env, value_regno)) { | |
61bd5218 JK |
2842 | verbose(env, "R%d leaks addr into packet\n", |
2843 | value_regno); | |
4acf6c0b BB |
2844 | return -EACCES; |
2845 | } | |
9fd29c08 | 2846 | err = check_packet_access(env, regno, off, size, false); |
969bf05e | 2847 | if (!err && t == BPF_READ && value_regno >= 0) |
638f5b90 | 2848 | mark_reg_unknown(env, regs, value_regno); |
d58e468b PP |
2849 | } else if (reg->type == PTR_TO_FLOW_KEYS) { |
2850 | if (t == BPF_WRITE && value_regno >= 0 && | |
2851 | is_pointer_value(env, value_regno)) { | |
2852 | verbose(env, "R%d leaks addr into flow keys\n", | |
2853 | value_regno); | |
2854 | return -EACCES; | |
2855 | } | |
2856 | ||
2857 | err = check_flow_keys_access(env, off, size); | |
2858 | if (!err && t == BPF_READ && value_regno >= 0) | |
2859 | mark_reg_unknown(env, regs, value_regno); | |
46f8bc92 | 2860 | } else if (type_is_sk_pointer(reg->type)) { |
c64b7983 | 2861 | if (t == BPF_WRITE) { |
46f8bc92 MKL |
2862 | verbose(env, "R%d cannot write into %s\n", |
2863 | regno, reg_type_str[reg->type]); | |
c64b7983 JS |
2864 | return -EACCES; |
2865 | } | |
5f456649 | 2866 | err = check_sock_access(env, insn_idx, regno, off, size, t); |
c64b7983 JS |
2867 | if (!err && value_regno >= 0) |
2868 | mark_reg_unknown(env, regs, value_regno); | |
9df1c28b MM |
2869 | } else if (reg->type == PTR_TO_TP_BUFFER) { |
2870 | err = check_tp_buffer_access(env, reg, regno, off, size); | |
2871 | if (!err && t == BPF_READ && value_regno >= 0) | |
2872 | mark_reg_unknown(env, regs, value_regno); | |
17a52670 | 2873 | } else { |
61bd5218 JK |
2874 | verbose(env, "R%d invalid mem access '%s'\n", regno, |
2875 | reg_type_str[reg->type]); | |
17a52670 AS |
2876 | return -EACCES; |
2877 | } | |
969bf05e | 2878 | |
f1174f77 | 2879 | if (!err && size < BPF_REG_SIZE && value_regno >= 0 && t == BPF_READ && |
638f5b90 | 2880 | regs[value_regno].type == SCALAR_VALUE) { |
f1174f77 | 2881 | /* b/h/w load zero-extends, mark upper bits as known 0 */ |
0c17d1d2 | 2882 | coerce_reg_to_size(®s[value_regno], size); |
969bf05e | 2883 | } |
17a52670 AS |
2884 | return err; |
2885 | } | |
2886 | ||
31fd8581 | 2887 | static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_insn *insn) |
17a52670 | 2888 | { |
17a52670 AS |
2889 | int err; |
2890 | ||
2891 | if ((BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) || | |
2892 | insn->imm != 0) { | |
61bd5218 | 2893 | verbose(env, "BPF_XADD uses reserved fields\n"); |
17a52670 AS |
2894 | return -EINVAL; |
2895 | } | |
2896 | ||
2897 | /* check src1 operand */ | |
dc503a8a | 2898 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
2899 | if (err) |
2900 | return err; | |
2901 | ||
2902 | /* check src2 operand */ | |
dc503a8a | 2903 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
2904 | if (err) |
2905 | return err; | |
2906 | ||
6bdf6abc | 2907 | if (is_pointer_value(env, insn->src_reg)) { |
61bd5218 | 2908 | verbose(env, "R%d leaks addr into mem\n", insn->src_reg); |
6bdf6abc DB |
2909 | return -EACCES; |
2910 | } | |
2911 | ||
ca369602 | 2912 | if (is_ctx_reg(env, insn->dst_reg) || |
4b5defde | 2913 | is_pkt_reg(env, insn->dst_reg) || |
46f8bc92 MKL |
2914 | is_flow_key_reg(env, insn->dst_reg) || |
2915 | is_sk_reg(env, insn->dst_reg)) { | |
ca369602 | 2916 | verbose(env, "BPF_XADD stores into R%d %s is not allowed\n", |
2a159c6f DB |
2917 | insn->dst_reg, |
2918 | reg_type_str[reg_state(env, insn->dst_reg)->type]); | |
f37a8cb8 DB |
2919 | return -EACCES; |
2920 | } | |
2921 | ||
17a52670 | 2922 | /* check whether atomic_add can read the memory */ |
31fd8581 | 2923 | err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off, |
ca369602 | 2924 | BPF_SIZE(insn->code), BPF_READ, -1, true); |
17a52670 AS |
2925 | if (err) |
2926 | return err; | |
2927 | ||
2928 | /* check whether atomic_add can write into the same memory */ | |
31fd8581 | 2929 | return check_mem_access(env, insn_idx, insn->dst_reg, insn->off, |
ca369602 | 2930 | BPF_SIZE(insn->code), BPF_WRITE, -1, true); |
17a52670 AS |
2931 | } |
2932 | ||
2011fccf AI |
2933 | static int __check_stack_boundary(struct bpf_verifier_env *env, u32 regno, |
2934 | int off, int access_size, | |
2935 | bool zero_size_allowed) | |
2936 | { | |
2937 | struct bpf_reg_state *reg = reg_state(env, regno); | |
2938 | ||
2939 | if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 || | |
2940 | access_size < 0 || (access_size == 0 && !zero_size_allowed)) { | |
2941 | if (tnum_is_const(reg->var_off)) { | |
2942 | verbose(env, "invalid stack type R%d off=%d access_size=%d\n", | |
2943 | regno, off, access_size); | |
2944 | } else { | |
2945 | char tn_buf[48]; | |
2946 | ||
2947 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
2948 | verbose(env, "invalid stack type R%d var_off=%s access_size=%d\n", | |
2949 | regno, tn_buf, access_size); | |
2950 | } | |
2951 | return -EACCES; | |
2952 | } | |
2953 | return 0; | |
2954 | } | |
2955 | ||
17a52670 AS |
2956 | /* when register 'regno' is passed into function that will read 'access_size' |
2957 | * bytes from that pointer, make sure that it's within stack boundary | |
f1174f77 EC |
2958 | * and all elements of stack are initialized. |
2959 | * Unlike most pointer bounds-checking functions, this one doesn't take an | |
2960 | * 'off' argument, so it has to add in reg->off itself. | |
17a52670 | 2961 | */ |
58e2af8b | 2962 | static int check_stack_boundary(struct bpf_verifier_env *env, int regno, |
435faee1 DB |
2963 | int access_size, bool zero_size_allowed, |
2964 | struct bpf_call_arg_meta *meta) | |
17a52670 | 2965 | { |
2a159c6f | 2966 | struct bpf_reg_state *reg = reg_state(env, regno); |
f4d7e40a | 2967 | struct bpf_func_state *state = func(env, reg); |
f7cf25b2 | 2968 | int err, min_off, max_off, i, j, slot, spi; |
17a52670 | 2969 | |
914cb781 | 2970 | if (reg->type != PTR_TO_STACK) { |
f1174f77 | 2971 | /* Allow zero-byte read from NULL, regardless of pointer type */ |
8e2fe1d9 | 2972 | if (zero_size_allowed && access_size == 0 && |
914cb781 | 2973 | register_is_null(reg)) |
8e2fe1d9 DB |
2974 | return 0; |
2975 | ||
61bd5218 | 2976 | verbose(env, "R%d type=%s expected=%s\n", regno, |
914cb781 | 2977 | reg_type_str[reg->type], |
8e2fe1d9 | 2978 | reg_type_str[PTR_TO_STACK]); |
17a52670 | 2979 | return -EACCES; |
8e2fe1d9 | 2980 | } |
17a52670 | 2981 | |
2011fccf AI |
2982 | if (tnum_is_const(reg->var_off)) { |
2983 | min_off = max_off = reg->var_off.value + reg->off; | |
2984 | err = __check_stack_boundary(env, regno, min_off, access_size, | |
2985 | zero_size_allowed); | |
2986 | if (err) | |
2987 | return err; | |
2988 | } else { | |
088ec26d AI |
2989 | /* Variable offset is prohibited for unprivileged mode for |
2990 | * simplicity since it requires corresponding support in | |
2991 | * Spectre masking for stack ALU. | |
2992 | * See also retrieve_ptr_limit(). | |
2993 | */ | |
2994 | if (!env->allow_ptr_leaks) { | |
2995 | char tn_buf[48]; | |
f1174f77 | 2996 | |
088ec26d AI |
2997 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); |
2998 | verbose(env, "R%d indirect variable offset stack access prohibited for !root, var_off=%s\n", | |
2999 | regno, tn_buf); | |
3000 | return -EACCES; | |
3001 | } | |
f2bcd05e AI |
3002 | /* Only initialized buffer on stack is allowed to be accessed |
3003 | * with variable offset. With uninitialized buffer it's hard to | |
3004 | * guarantee that whole memory is marked as initialized on | |
3005 | * helper return since specific bounds are unknown what may | |
3006 | * cause uninitialized stack leaking. | |
3007 | */ | |
3008 | if (meta && meta->raw_mode) | |
3009 | meta = NULL; | |
3010 | ||
107c26a7 AI |
3011 | if (reg->smax_value >= BPF_MAX_VAR_OFF || |
3012 | reg->smax_value <= -BPF_MAX_VAR_OFF) { | |
3013 | verbose(env, "R%d unbounded indirect variable offset stack access\n", | |
3014 | regno); | |
3015 | return -EACCES; | |
3016 | } | |
2011fccf | 3017 | min_off = reg->smin_value + reg->off; |
107c26a7 | 3018 | max_off = reg->smax_value + reg->off; |
2011fccf AI |
3019 | err = __check_stack_boundary(env, regno, min_off, access_size, |
3020 | zero_size_allowed); | |
107c26a7 AI |
3021 | if (err) { |
3022 | verbose(env, "R%d min value is outside of stack bound\n", | |
3023 | regno); | |
2011fccf | 3024 | return err; |
107c26a7 | 3025 | } |
2011fccf AI |
3026 | err = __check_stack_boundary(env, regno, max_off, access_size, |
3027 | zero_size_allowed); | |
107c26a7 AI |
3028 | if (err) { |
3029 | verbose(env, "R%d max value is outside of stack bound\n", | |
3030 | regno); | |
2011fccf | 3031 | return err; |
107c26a7 | 3032 | } |
17a52670 AS |
3033 | } |
3034 | ||
435faee1 DB |
3035 | if (meta && meta->raw_mode) { |
3036 | meta->access_size = access_size; | |
3037 | meta->regno = regno; | |
3038 | return 0; | |
3039 | } | |
3040 | ||
2011fccf | 3041 | for (i = min_off; i < max_off + access_size; i++) { |
cc2b14d5 AS |
3042 | u8 *stype; |
3043 | ||
2011fccf | 3044 | slot = -i - 1; |
638f5b90 | 3045 | spi = slot / BPF_REG_SIZE; |
cc2b14d5 AS |
3046 | if (state->allocated_stack <= slot) |
3047 | goto err; | |
3048 | stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE]; | |
3049 | if (*stype == STACK_MISC) | |
3050 | goto mark; | |
3051 | if (*stype == STACK_ZERO) { | |
3052 | /* helper can write anything into the stack */ | |
3053 | *stype = STACK_MISC; | |
3054 | goto mark; | |
17a52670 | 3055 | } |
f7cf25b2 AS |
3056 | if (state->stack[spi].slot_type[0] == STACK_SPILL && |
3057 | state->stack[spi].spilled_ptr.type == SCALAR_VALUE) { | |
3058 | __mark_reg_unknown(&state->stack[spi].spilled_ptr); | |
3059 | for (j = 0; j < BPF_REG_SIZE; j++) | |
3060 | state->stack[spi].slot_type[j] = STACK_MISC; | |
3061 | goto mark; | |
3062 | } | |
3063 | ||
cc2b14d5 | 3064 | err: |
2011fccf AI |
3065 | if (tnum_is_const(reg->var_off)) { |
3066 | verbose(env, "invalid indirect read from stack off %d+%d size %d\n", | |
3067 | min_off, i - min_off, access_size); | |
3068 | } else { | |
3069 | char tn_buf[48]; | |
3070 | ||
3071 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); | |
3072 | verbose(env, "invalid indirect read from stack var_off %s+%d size %d\n", | |
3073 | tn_buf, i - min_off, access_size); | |
3074 | } | |
cc2b14d5 AS |
3075 | return -EACCES; |
3076 | mark: | |
3077 | /* reading any byte out of 8-byte 'spill_slot' will cause | |
3078 | * the whole slot to be marked as 'read' | |
3079 | */ | |
679c782d | 3080 | mark_reg_read(env, &state->stack[spi].spilled_ptr, |
5327ed3d JW |
3081 | state->stack[spi].spilled_ptr.parent, |
3082 | REG_LIVE_READ64); | |
17a52670 | 3083 | } |
2011fccf | 3084 | return update_stack_depth(env, state, min_off); |
17a52670 AS |
3085 | } |
3086 | ||
06c1c049 GB |
3087 | static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, |
3088 | int access_size, bool zero_size_allowed, | |
3089 | struct bpf_call_arg_meta *meta) | |
3090 | { | |
638f5b90 | 3091 | struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; |
06c1c049 | 3092 | |
f1174f77 | 3093 | switch (reg->type) { |
06c1c049 | 3094 | case PTR_TO_PACKET: |
de8f3a83 | 3095 | case PTR_TO_PACKET_META: |
9fd29c08 YS |
3096 | return check_packet_access(env, regno, reg->off, access_size, |
3097 | zero_size_allowed); | |
06c1c049 | 3098 | case PTR_TO_MAP_VALUE: |
591fe988 DB |
3099 | if (check_map_access_type(env, regno, reg->off, access_size, |
3100 | meta && meta->raw_mode ? BPF_WRITE : | |
3101 | BPF_READ)) | |
3102 | return -EACCES; | |
9fd29c08 YS |
3103 | return check_map_access(env, regno, reg->off, access_size, |
3104 | zero_size_allowed); | |
f1174f77 | 3105 | default: /* scalar_value|ptr_to_stack or invalid ptr */ |
06c1c049 GB |
3106 | return check_stack_boundary(env, regno, access_size, |
3107 | zero_size_allowed, meta); | |
3108 | } | |
3109 | } | |
3110 | ||
d83525ca AS |
3111 | /* Implementation details: |
3112 | * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL | |
3113 | * Two bpf_map_lookups (even with the same key) will have different reg->id. | |
3114 | * For traditional PTR_TO_MAP_VALUE the verifier clears reg->id after | |
3115 | * value_or_null->value transition, since the verifier only cares about | |
3116 | * the range of access to valid map value pointer and doesn't care about actual | |
3117 | * address of the map element. | |
3118 | * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps | |
3119 | * reg->id > 0 after value_or_null->value transition. By doing so | |
3120 | * two bpf_map_lookups will be considered two different pointers that | |
3121 | * point to different bpf_spin_locks. | |
3122 | * The verifier allows taking only one bpf_spin_lock at a time to avoid | |
3123 | * dead-locks. | |
3124 | * Since only one bpf_spin_lock is allowed the checks are simpler than | |
3125 | * reg_is_refcounted() logic. The verifier needs to remember only | |
3126 | * one spin_lock instead of array of acquired_refs. | |
3127 | * cur_state->active_spin_lock remembers which map value element got locked | |
3128 | * and clears it after bpf_spin_unlock. | |
3129 | */ | |
3130 | static int process_spin_lock(struct bpf_verifier_env *env, int regno, | |
3131 | bool is_lock) | |
3132 | { | |
3133 | struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; | |
3134 | struct bpf_verifier_state *cur = env->cur_state; | |
3135 | bool is_const = tnum_is_const(reg->var_off); | |
3136 | struct bpf_map *map = reg->map_ptr; | |
3137 | u64 val = reg->var_off.value; | |
3138 | ||
3139 | if (reg->type != PTR_TO_MAP_VALUE) { | |
3140 | verbose(env, "R%d is not a pointer to map_value\n", regno); | |
3141 | return -EINVAL; | |
3142 | } | |
3143 | if (!is_const) { | |
3144 | verbose(env, | |
3145 | "R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n", | |
3146 | regno); | |
3147 | return -EINVAL; | |
3148 | } | |
3149 | if (!map->btf) { | |
3150 | verbose(env, | |
3151 | "map '%s' has to have BTF in order to use bpf_spin_lock\n", | |
3152 | map->name); | |
3153 | return -EINVAL; | |
3154 | } | |
3155 | if (!map_value_has_spin_lock(map)) { | |
3156 | if (map->spin_lock_off == -E2BIG) | |
3157 | verbose(env, | |
3158 | "map '%s' has more than one 'struct bpf_spin_lock'\n", | |
3159 | map->name); | |
3160 | else if (map->spin_lock_off == -ENOENT) | |
3161 | verbose(env, | |
3162 | "map '%s' doesn't have 'struct bpf_spin_lock'\n", | |
3163 | map->name); | |
3164 | else | |
3165 | verbose(env, | |
3166 | "map '%s' is not a struct type or bpf_spin_lock is mangled\n", | |
3167 | map->name); | |
3168 | return -EINVAL; | |
3169 | } | |
3170 | if (map->spin_lock_off != val + reg->off) { | |
3171 | verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock'\n", | |
3172 | val + reg->off); | |
3173 | return -EINVAL; | |
3174 | } | |
3175 | if (is_lock) { | |
3176 | if (cur->active_spin_lock) { | |
3177 | verbose(env, | |
3178 | "Locking two bpf_spin_locks are not allowed\n"); | |
3179 | return -EINVAL; | |
3180 | } | |
3181 | cur->active_spin_lock = reg->id; | |
3182 | } else { | |
3183 | if (!cur->active_spin_lock) { | |
3184 | verbose(env, "bpf_spin_unlock without taking a lock\n"); | |
3185 | return -EINVAL; | |
3186 | } | |
3187 | if (cur->active_spin_lock != reg->id) { | |
3188 | verbose(env, "bpf_spin_unlock of different lock\n"); | |
3189 | return -EINVAL; | |
3190 | } | |
3191 | cur->active_spin_lock = 0; | |
3192 | } | |
3193 | return 0; | |
3194 | } | |
3195 | ||
90133415 DB |
3196 | static bool arg_type_is_mem_ptr(enum bpf_arg_type type) |
3197 | { | |
3198 | return type == ARG_PTR_TO_MEM || | |
3199 | type == ARG_PTR_TO_MEM_OR_NULL || | |
3200 | type == ARG_PTR_TO_UNINIT_MEM; | |
3201 | } | |
3202 | ||
3203 | static bool arg_type_is_mem_size(enum bpf_arg_type type) | |
3204 | { | |
3205 | return type == ARG_CONST_SIZE || | |
3206 | type == ARG_CONST_SIZE_OR_ZERO; | |
3207 | } | |
3208 | ||
57c3bb72 AI |
3209 | static bool arg_type_is_int_ptr(enum bpf_arg_type type) |
3210 | { | |
3211 | return type == ARG_PTR_TO_INT || | |
3212 | type == ARG_PTR_TO_LONG; | |
3213 | } | |
3214 | ||
3215 | static int int_ptr_type_to_size(enum bpf_arg_type type) | |
3216 | { | |
3217 | if (type == ARG_PTR_TO_INT) | |
3218 | return sizeof(u32); | |
3219 | else if (type == ARG_PTR_TO_LONG) | |
3220 | return sizeof(u64); | |
3221 | ||
3222 | return -EINVAL; | |
3223 | } | |
3224 | ||
58e2af8b | 3225 | static int check_func_arg(struct bpf_verifier_env *env, u32 regno, |
33ff9823 DB |
3226 | enum bpf_arg_type arg_type, |
3227 | struct bpf_call_arg_meta *meta) | |
17a52670 | 3228 | { |
638f5b90 | 3229 | struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; |
6841de8b | 3230 | enum bpf_reg_type expected_type, type = reg->type; |
17a52670 AS |
3231 | int err = 0; |
3232 | ||
80f1d68c | 3233 | if (arg_type == ARG_DONTCARE) |
17a52670 AS |
3234 | return 0; |
3235 | ||
dc503a8a EC |
3236 | err = check_reg_arg(env, regno, SRC_OP); |
3237 | if (err) | |
3238 | return err; | |
17a52670 | 3239 | |
1be7f75d AS |
3240 | if (arg_type == ARG_ANYTHING) { |
3241 | if (is_pointer_value(env, regno)) { | |
61bd5218 JK |
3242 | verbose(env, "R%d leaks addr into helper function\n", |
3243 | regno); | |
1be7f75d AS |
3244 | return -EACCES; |
3245 | } | |
80f1d68c | 3246 | return 0; |
1be7f75d | 3247 | } |
80f1d68c | 3248 | |
de8f3a83 | 3249 | if (type_is_pkt_pointer(type) && |
3a0af8fd | 3250 | !may_access_direct_pkt_data(env, meta, BPF_READ)) { |
61bd5218 | 3251 | verbose(env, "helper access to the packet is not allowed\n"); |
6841de8b AS |
3252 | return -EACCES; |
3253 | } | |
3254 | ||
8e2fe1d9 | 3255 | if (arg_type == ARG_PTR_TO_MAP_KEY || |
2ea864c5 | 3256 | arg_type == ARG_PTR_TO_MAP_VALUE || |
6ac99e8f MKL |
3257 | arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE || |
3258 | arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL) { | |
17a52670 | 3259 | expected_type = PTR_TO_STACK; |
6ac99e8f MKL |
3260 | if (register_is_null(reg) && |
3261 | arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL) | |
3262 | /* final test in check_stack_boundary() */; | |
3263 | else if (!type_is_pkt_pointer(type) && | |
3264 | type != PTR_TO_MAP_VALUE && | |
3265 | type != expected_type) | |
6841de8b | 3266 | goto err_type; |
39f19ebb AS |
3267 | } else if (arg_type == ARG_CONST_SIZE || |
3268 | arg_type == ARG_CONST_SIZE_OR_ZERO) { | |
f1174f77 EC |
3269 | expected_type = SCALAR_VALUE; |
3270 | if (type != expected_type) | |
6841de8b | 3271 | goto err_type; |
17a52670 AS |
3272 | } else if (arg_type == ARG_CONST_MAP_PTR) { |
3273 | expected_type = CONST_PTR_TO_MAP; | |
6841de8b AS |
3274 | if (type != expected_type) |
3275 | goto err_type; | |
608cd71a AS |
3276 | } else if (arg_type == ARG_PTR_TO_CTX) { |
3277 | expected_type = PTR_TO_CTX; | |
6841de8b AS |
3278 | if (type != expected_type) |
3279 | goto err_type; | |
58990d1f DB |
3280 | err = check_ctx_reg(env, reg, regno); |
3281 | if (err < 0) | |
3282 | return err; | |
46f8bc92 MKL |
3283 | } else if (arg_type == ARG_PTR_TO_SOCK_COMMON) { |
3284 | expected_type = PTR_TO_SOCK_COMMON; | |
3285 | /* Any sk pointer can be ARG_PTR_TO_SOCK_COMMON */ | |
3286 | if (!type_is_sk_pointer(type)) | |
3287 | goto err_type; | |
1b986589 MKL |
3288 | if (reg->ref_obj_id) { |
3289 | if (meta->ref_obj_id) { | |
3290 | verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n", | |
3291 | regno, reg->ref_obj_id, | |
3292 | meta->ref_obj_id); | |
3293 | return -EFAULT; | |
3294 | } | |
3295 | meta->ref_obj_id = reg->ref_obj_id; | |
fd978bf7 | 3296 | } |
6ac99e8f MKL |
3297 | } else if (arg_type == ARG_PTR_TO_SOCKET) { |
3298 | expected_type = PTR_TO_SOCKET; | |
3299 | if (type != expected_type) | |
3300 | goto err_type; | |
d83525ca AS |
3301 | } else if (arg_type == ARG_PTR_TO_SPIN_LOCK) { |
3302 | if (meta->func_id == BPF_FUNC_spin_lock) { | |
3303 | if (process_spin_lock(env, regno, true)) | |
3304 | return -EACCES; | |
3305 | } else if (meta->func_id == BPF_FUNC_spin_unlock) { | |
3306 | if (process_spin_lock(env, regno, false)) | |
3307 | return -EACCES; | |
3308 | } else { | |
3309 | verbose(env, "verifier internal error\n"); | |
3310 | return -EFAULT; | |
3311 | } | |
90133415 | 3312 | } else if (arg_type_is_mem_ptr(arg_type)) { |
8e2fe1d9 DB |
3313 | expected_type = PTR_TO_STACK; |
3314 | /* One exception here. In case function allows for NULL to be | |
f1174f77 | 3315 | * passed in as argument, it's a SCALAR_VALUE type. Final test |
8e2fe1d9 DB |
3316 | * happens during stack boundary checking. |
3317 | */ | |
914cb781 | 3318 | if (register_is_null(reg) && |
db1ac496 | 3319 | arg_type == ARG_PTR_TO_MEM_OR_NULL) |
6841de8b | 3320 | /* final test in check_stack_boundary() */; |
de8f3a83 DB |
3321 | else if (!type_is_pkt_pointer(type) && |
3322 | type != PTR_TO_MAP_VALUE && | |
f1174f77 | 3323 | type != expected_type) |
6841de8b | 3324 | goto err_type; |
39f19ebb | 3325 | meta->raw_mode = arg_type == ARG_PTR_TO_UNINIT_MEM; |
57c3bb72 AI |
3326 | } else if (arg_type_is_int_ptr(arg_type)) { |
3327 | expected_type = PTR_TO_STACK; | |
3328 | if (!type_is_pkt_pointer(type) && | |
3329 | type != PTR_TO_MAP_VALUE && | |
3330 | type != expected_type) | |
3331 | goto err_type; | |
17a52670 | 3332 | } else { |
61bd5218 | 3333 | verbose(env, "unsupported arg_type %d\n", arg_type); |
17a52670 AS |
3334 | return -EFAULT; |
3335 | } | |
3336 | ||
17a52670 AS |
3337 | if (arg_type == ARG_CONST_MAP_PTR) { |
3338 | /* bpf_map_xxx(map_ptr) call: remember that map_ptr */ | |
33ff9823 | 3339 | meta->map_ptr = reg->map_ptr; |
17a52670 AS |
3340 | } else if (arg_type == ARG_PTR_TO_MAP_KEY) { |
3341 | /* bpf_map_xxx(..., map_ptr, ..., key) call: | |
3342 | * check that [key, key + map->key_size) are within | |
3343 | * stack limits and initialized | |
3344 | */ | |
33ff9823 | 3345 | if (!meta->map_ptr) { |
17a52670 AS |
3346 | /* in function declaration map_ptr must come before |
3347 | * map_key, so that it's verified and known before | |
3348 | * we have to check map_key here. Otherwise it means | |
3349 | * that kernel subsystem misconfigured verifier | |
3350 | */ | |
61bd5218 | 3351 | verbose(env, "invalid map_ptr to access map->key\n"); |
17a52670 AS |
3352 | return -EACCES; |
3353 | } | |
d71962f3 PC |
3354 | err = check_helper_mem_access(env, regno, |
3355 | meta->map_ptr->key_size, false, | |
3356 | NULL); | |
2ea864c5 | 3357 | } else if (arg_type == ARG_PTR_TO_MAP_VALUE || |
6ac99e8f MKL |
3358 | (arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL && |
3359 | !register_is_null(reg)) || | |
2ea864c5 | 3360 | arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE) { |
17a52670 AS |
3361 | /* bpf_map_xxx(..., map_ptr, ..., value) call: |
3362 | * check [value, value + map->value_size) validity | |
3363 | */ | |
33ff9823 | 3364 | if (!meta->map_ptr) { |
17a52670 | 3365 | /* kernel subsystem misconfigured verifier */ |
61bd5218 | 3366 | verbose(env, "invalid map_ptr to access map->value\n"); |
17a52670 AS |
3367 | return -EACCES; |
3368 | } | |
2ea864c5 | 3369 | meta->raw_mode = (arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE); |
d71962f3 PC |
3370 | err = check_helper_mem_access(env, regno, |
3371 | meta->map_ptr->value_size, false, | |
2ea864c5 | 3372 | meta); |
90133415 | 3373 | } else if (arg_type_is_mem_size(arg_type)) { |
39f19ebb | 3374 | bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO); |
17a52670 | 3375 | |
849fa506 YS |
3376 | /* remember the mem_size which may be used later |
3377 | * to refine return values. | |
3378 | */ | |
3379 | meta->msize_smax_value = reg->smax_value; | |
3380 | meta->msize_umax_value = reg->umax_value; | |
3381 | ||
f1174f77 EC |
3382 | /* The register is SCALAR_VALUE; the access check |
3383 | * happens using its boundaries. | |
06c1c049 | 3384 | */ |
f1174f77 | 3385 | if (!tnum_is_const(reg->var_off)) |
06c1c049 GB |
3386 | /* For unprivileged variable accesses, disable raw |
3387 | * mode so that the program is required to | |
3388 | * initialize all the memory that the helper could | |
3389 | * just partially fill up. | |
3390 | */ | |
3391 | meta = NULL; | |
3392 | ||
b03c9f9f | 3393 | if (reg->smin_value < 0) { |
61bd5218 | 3394 | verbose(env, "R%d min value is negative, either use unsigned or 'var &= const'\n", |
f1174f77 EC |
3395 | regno); |
3396 | return -EACCES; | |
3397 | } | |
06c1c049 | 3398 | |
b03c9f9f | 3399 | if (reg->umin_value == 0) { |
f1174f77 EC |
3400 | err = check_helper_mem_access(env, regno - 1, 0, |
3401 | zero_size_allowed, | |
3402 | meta); | |
06c1c049 GB |
3403 | if (err) |
3404 | return err; | |
06c1c049 | 3405 | } |
f1174f77 | 3406 | |
b03c9f9f | 3407 | if (reg->umax_value >= BPF_MAX_VAR_SIZ) { |
61bd5218 | 3408 | verbose(env, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n", |
f1174f77 EC |
3409 | regno); |
3410 | return -EACCES; | |
3411 | } | |
3412 | err = check_helper_mem_access(env, regno - 1, | |
b03c9f9f | 3413 | reg->umax_value, |
f1174f77 | 3414 | zero_size_allowed, meta); |
b5dc0163 AS |
3415 | if (!err) |
3416 | err = mark_chain_precision(env, regno); | |
57c3bb72 AI |
3417 | } else if (arg_type_is_int_ptr(arg_type)) { |
3418 | int size = int_ptr_type_to_size(arg_type); | |
3419 | ||
3420 | err = check_helper_mem_access(env, regno, size, false, meta); | |
3421 | if (err) | |
3422 | return err; | |
3423 | err = check_ptr_alignment(env, reg, 0, size, true); | |
17a52670 AS |
3424 | } |
3425 | ||
3426 | return err; | |
6841de8b | 3427 | err_type: |
61bd5218 | 3428 | verbose(env, "R%d type=%s expected=%s\n", regno, |
6841de8b AS |
3429 | reg_type_str[type], reg_type_str[expected_type]); |
3430 | return -EACCES; | |
17a52670 AS |
3431 | } |
3432 | ||
61bd5218 JK |
3433 | static int check_map_func_compatibility(struct bpf_verifier_env *env, |
3434 | struct bpf_map *map, int func_id) | |
35578d79 | 3435 | { |
35578d79 KX |
3436 | if (!map) |
3437 | return 0; | |
3438 | ||
6aff67c8 AS |
3439 | /* We need a two way check, first is from map perspective ... */ |
3440 | switch (map->map_type) { | |
3441 | case BPF_MAP_TYPE_PROG_ARRAY: | |
3442 | if (func_id != BPF_FUNC_tail_call) | |
3443 | goto error; | |
3444 | break; | |
3445 | case BPF_MAP_TYPE_PERF_EVENT_ARRAY: | |
3446 | if (func_id != BPF_FUNC_perf_event_read && | |
908432ca YS |
3447 | func_id != BPF_FUNC_perf_event_output && |
3448 | func_id != BPF_FUNC_perf_event_read_value) | |
6aff67c8 AS |
3449 | goto error; |
3450 | break; | |
3451 | case BPF_MAP_TYPE_STACK_TRACE: | |
3452 | if (func_id != BPF_FUNC_get_stackid) | |
3453 | goto error; | |
3454 | break; | |
4ed8ec52 | 3455 | case BPF_MAP_TYPE_CGROUP_ARRAY: |
60747ef4 | 3456 | if (func_id != BPF_FUNC_skb_under_cgroup && |
60d20f91 | 3457 | func_id != BPF_FUNC_current_task_under_cgroup) |
4a482f34 MKL |
3458 | goto error; |
3459 | break; | |
cd339431 | 3460 | case BPF_MAP_TYPE_CGROUP_STORAGE: |
b741f163 | 3461 | case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE: |
cd339431 RG |
3462 | if (func_id != BPF_FUNC_get_local_storage) |
3463 | goto error; | |
3464 | break; | |
546ac1ff | 3465 | case BPF_MAP_TYPE_DEVMAP: |
6f9d451a | 3466 | case BPF_MAP_TYPE_DEVMAP_HASH: |
0cdbb4b0 THJ |
3467 | if (func_id != BPF_FUNC_redirect_map && |
3468 | func_id != BPF_FUNC_map_lookup_elem) | |
546ac1ff JF |
3469 | goto error; |
3470 | break; | |
fbfc504a BT |
3471 | /* Restrict bpf side of cpumap and xskmap, open when use-cases |
3472 | * appear. | |
3473 | */ | |
6710e112 JDB |
3474 | case BPF_MAP_TYPE_CPUMAP: |
3475 | if (func_id != BPF_FUNC_redirect_map) | |
3476 | goto error; | |
3477 | break; | |
fada7fdc JL |
3478 | case BPF_MAP_TYPE_XSKMAP: |
3479 | if (func_id != BPF_FUNC_redirect_map && | |
3480 | func_id != BPF_FUNC_map_lookup_elem) | |
3481 | goto error; | |
3482 | break; | |
56f668df | 3483 | case BPF_MAP_TYPE_ARRAY_OF_MAPS: |
bcc6b1b7 | 3484 | case BPF_MAP_TYPE_HASH_OF_MAPS: |
56f668df MKL |
3485 | if (func_id != BPF_FUNC_map_lookup_elem) |
3486 | goto error; | |
16a43625 | 3487 | break; |
174a79ff JF |
3488 | case BPF_MAP_TYPE_SOCKMAP: |
3489 | if (func_id != BPF_FUNC_sk_redirect_map && | |
3490 | func_id != BPF_FUNC_sock_map_update && | |
4f738adb JF |
3491 | func_id != BPF_FUNC_map_delete_elem && |
3492 | func_id != BPF_FUNC_msg_redirect_map) | |
174a79ff JF |
3493 | goto error; |
3494 | break; | |
81110384 JF |
3495 | case BPF_MAP_TYPE_SOCKHASH: |
3496 | if (func_id != BPF_FUNC_sk_redirect_hash && | |
3497 | func_id != BPF_FUNC_sock_hash_update && | |
3498 | func_id != BPF_FUNC_map_delete_elem && | |
3499 | func_id != BPF_FUNC_msg_redirect_hash) | |
3500 | goto error; | |
3501 | break; | |
2dbb9b9e MKL |
3502 | case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY: |
3503 | if (func_id != BPF_FUNC_sk_select_reuseport) | |
3504 | goto error; | |
3505 | break; | |
f1a2e44a MV |
3506 | case BPF_MAP_TYPE_QUEUE: |
3507 | case BPF_MAP_TYPE_STACK: | |
3508 | if (func_id != BPF_FUNC_map_peek_elem && | |
3509 | func_id != BPF_FUNC_map_pop_elem && | |
3510 | func_id != BPF_FUNC_map_push_elem) | |
3511 | goto error; | |
3512 | break; | |
6ac99e8f MKL |
3513 | case BPF_MAP_TYPE_SK_STORAGE: |
3514 | if (func_id != BPF_FUNC_sk_storage_get && | |
3515 | func_id != BPF_FUNC_sk_storage_delete) | |
3516 | goto error; | |
3517 | break; | |
6aff67c8 AS |
3518 | default: |
3519 | break; | |
3520 | } | |
3521 | ||
3522 | /* ... and second from the function itself. */ | |
3523 | switch (func_id) { | |
3524 | case BPF_FUNC_tail_call: | |
3525 | if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) | |
3526 | goto error; | |
f910cefa | 3527 | if (env->subprog_cnt > 1) { |
f4d7e40a AS |
3528 | verbose(env, "tail_calls are not allowed in programs with bpf-to-bpf calls\n"); |
3529 | return -EINVAL; | |
3530 | } | |
6aff67c8 AS |
3531 | break; |
3532 | case BPF_FUNC_perf_event_read: | |
3533 | case BPF_FUNC_perf_event_output: | |
908432ca | 3534 | case BPF_FUNC_perf_event_read_value: |
6aff67c8 AS |
3535 | if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) |
3536 | goto error; | |
3537 | break; | |
3538 | case BPF_FUNC_get_stackid: | |
3539 | if (map->map_type != BPF_MAP_TYPE_STACK_TRACE) | |
3540 | goto error; | |
3541 | break; | |
60d20f91 | 3542 | case BPF_FUNC_current_task_under_cgroup: |
747ea55e | 3543 | case BPF_FUNC_skb_under_cgroup: |
4a482f34 MKL |
3544 | if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY) |
3545 | goto error; | |
3546 | break; | |
97f91a7c | 3547 | case BPF_FUNC_redirect_map: |
9c270af3 | 3548 | if (map->map_type != BPF_MAP_TYPE_DEVMAP && |
6f9d451a | 3549 | map->map_type != BPF_MAP_TYPE_DEVMAP_HASH && |
fbfc504a BT |
3550 | map->map_type != BPF_MAP_TYPE_CPUMAP && |
3551 | map->map_type != BPF_MAP_TYPE_XSKMAP) | |
97f91a7c JF |
3552 | goto error; |
3553 | break; | |
174a79ff | 3554 | case BPF_FUNC_sk_redirect_map: |
4f738adb | 3555 | case BPF_FUNC_msg_redirect_map: |
81110384 | 3556 | case BPF_FUNC_sock_map_update: |
174a79ff JF |
3557 | if (map->map_type != BPF_MAP_TYPE_SOCKMAP) |
3558 | goto error; | |
3559 | break; | |
81110384 JF |
3560 | case BPF_FUNC_sk_redirect_hash: |
3561 | case BPF_FUNC_msg_redirect_hash: | |
3562 | case BPF_FUNC_sock_hash_update: | |
3563 | if (map->map_type != BPF_MAP_TYPE_SOCKHASH) | |
174a79ff JF |
3564 | goto error; |
3565 | break; | |
cd339431 | 3566 | case BPF_FUNC_get_local_storage: |
b741f163 RG |
3567 | if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE && |
3568 | map->map_type != BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) | |
cd339431 RG |
3569 | goto error; |
3570 | break; | |
2dbb9b9e MKL |
3571 | case BPF_FUNC_sk_select_reuseport: |
3572 | if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) | |
3573 | goto error; | |
3574 | break; | |
f1a2e44a MV |
3575 | case BPF_FUNC_map_peek_elem: |
3576 | case BPF_FUNC_map_pop_elem: | |
3577 | case BPF_FUNC_map_push_elem: | |
3578 | if (map->map_type != BPF_MAP_TYPE_QUEUE && | |
3579 | map->map_type != BPF_MAP_TYPE_STACK) | |
3580 | goto error; | |
3581 | break; | |
6ac99e8f MKL |
3582 | case BPF_FUNC_sk_storage_get: |
3583 | case BPF_FUNC_sk_storage_delete: | |
3584 | if (map->map_type != BPF_MAP_TYPE_SK_STORAGE) | |
3585 | goto error; | |
3586 | break; | |
6aff67c8 AS |
3587 | default: |
3588 | break; | |
35578d79 KX |
3589 | } |
3590 | ||
3591 | return 0; | |
6aff67c8 | 3592 | error: |
61bd5218 | 3593 | verbose(env, "cannot pass map_type %d into func %s#%d\n", |
ebb676da | 3594 | map->map_type, func_id_name(func_id), func_id); |
6aff67c8 | 3595 | return -EINVAL; |
35578d79 KX |
3596 | } |
3597 | ||
90133415 | 3598 | static bool check_raw_mode_ok(const struct bpf_func_proto *fn) |
435faee1 DB |
3599 | { |
3600 | int count = 0; | |
3601 | ||
39f19ebb | 3602 | if (fn->arg1_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 3603 | count++; |
39f19ebb | 3604 | if (fn->arg2_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 3605 | count++; |
39f19ebb | 3606 | if (fn->arg3_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 3607 | count++; |
39f19ebb | 3608 | if (fn->arg4_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 3609 | count++; |
39f19ebb | 3610 | if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 DB |
3611 | count++; |
3612 | ||
90133415 DB |
3613 | /* We only support one arg being in raw mode at the moment, |
3614 | * which is sufficient for the helper functions we have | |
3615 | * right now. | |
3616 | */ | |
3617 | return count <= 1; | |
3618 | } | |
3619 | ||
3620 | static bool check_args_pair_invalid(enum bpf_arg_type arg_curr, | |
3621 | enum bpf_arg_type arg_next) | |
3622 | { | |
3623 | return (arg_type_is_mem_ptr(arg_curr) && | |
3624 | !arg_type_is_mem_size(arg_next)) || | |
3625 | (!arg_type_is_mem_ptr(arg_curr) && | |
3626 | arg_type_is_mem_size(arg_next)); | |
3627 | } | |
3628 | ||
3629 | static bool check_arg_pair_ok(const struct bpf_func_proto *fn) | |
3630 | { | |
3631 | /* bpf_xxx(..., buf, len) call will access 'len' | |
3632 | * bytes from memory 'buf'. Both arg types need | |
3633 | * to be paired, so make sure there's no buggy | |
3634 | * helper function specification. | |
3635 | */ | |
3636 | if (arg_type_is_mem_size(fn->arg1_type) || | |
3637 | arg_type_is_mem_ptr(fn->arg5_type) || | |
3638 | check_args_pair_invalid(fn->arg1_type, fn->arg2_type) || | |
3639 | check_args_pair_invalid(fn->arg2_type, fn->arg3_type) || | |
3640 | check_args_pair_invalid(fn->arg3_type, fn->arg4_type) || | |
3641 | check_args_pair_invalid(fn->arg4_type, fn->arg5_type)) | |
3642 | return false; | |
3643 | ||
3644 | return true; | |
3645 | } | |
3646 | ||
1b986589 | 3647 | static bool check_refcount_ok(const struct bpf_func_proto *fn, int func_id) |
fd978bf7 JS |
3648 | { |
3649 | int count = 0; | |
3650 | ||
1b986589 | 3651 | if (arg_type_may_be_refcounted(fn->arg1_type)) |
fd978bf7 | 3652 | count++; |
1b986589 | 3653 | if (arg_type_may_be_refcounted(fn->arg2_type)) |
fd978bf7 | 3654 | count++; |
1b986589 | 3655 | if (arg_type_may_be_refcounted(fn->arg3_type)) |
fd978bf7 | 3656 | count++; |
1b986589 | 3657 | if (arg_type_may_be_refcounted(fn->arg4_type)) |
fd978bf7 | 3658 | count++; |
1b986589 | 3659 | if (arg_type_may_be_refcounted(fn->arg5_type)) |
fd978bf7 JS |
3660 | count++; |
3661 | ||
1b986589 MKL |
3662 | /* A reference acquiring function cannot acquire |
3663 | * another refcounted ptr. | |
3664 | */ | |
3665 | if (is_acquire_function(func_id) && count) | |
3666 | return false; | |
3667 | ||
fd978bf7 JS |
3668 | /* We only support one arg being unreferenced at the moment, |
3669 | * which is sufficient for the helper functions we have right now. | |
3670 | */ | |
3671 | return count <= 1; | |
3672 | } | |
3673 | ||
1b986589 | 3674 | static int check_func_proto(const struct bpf_func_proto *fn, int func_id) |
90133415 DB |
3675 | { |
3676 | return check_raw_mode_ok(fn) && | |
fd978bf7 | 3677 | check_arg_pair_ok(fn) && |
1b986589 | 3678 | check_refcount_ok(fn, func_id) ? 0 : -EINVAL; |
435faee1 DB |
3679 | } |
3680 | ||
de8f3a83 DB |
3681 | /* Packet data might have moved, any old PTR_TO_PACKET[_META,_END] |
3682 | * are now invalid, so turn them into unknown SCALAR_VALUE. | |
f1174f77 | 3683 | */ |
f4d7e40a AS |
3684 | static void __clear_all_pkt_pointers(struct bpf_verifier_env *env, |
3685 | struct bpf_func_state *state) | |
969bf05e | 3686 | { |
58e2af8b | 3687 | struct bpf_reg_state *regs = state->regs, *reg; |
969bf05e AS |
3688 | int i; |
3689 | ||
3690 | for (i = 0; i < MAX_BPF_REG; i++) | |
de8f3a83 | 3691 | if (reg_is_pkt_pointer_any(®s[i])) |
61bd5218 | 3692 | mark_reg_unknown(env, regs, i); |
969bf05e | 3693 | |
f3709f69 JS |
3694 | bpf_for_each_spilled_reg(i, state, reg) { |
3695 | if (!reg) | |
969bf05e | 3696 | continue; |
de8f3a83 DB |
3697 | if (reg_is_pkt_pointer_any(reg)) |
3698 | __mark_reg_unknown(reg); | |
969bf05e AS |
3699 | } |
3700 | } | |
3701 | ||
f4d7e40a AS |
3702 | static void clear_all_pkt_pointers(struct bpf_verifier_env *env) |
3703 | { | |
3704 | struct bpf_verifier_state *vstate = env->cur_state; | |
3705 | int i; | |
3706 | ||
3707 | for (i = 0; i <= vstate->curframe; i++) | |
3708 | __clear_all_pkt_pointers(env, vstate->frame[i]); | |
3709 | } | |
3710 | ||
fd978bf7 | 3711 | static void release_reg_references(struct bpf_verifier_env *env, |
1b986589 MKL |
3712 | struct bpf_func_state *state, |
3713 | int ref_obj_id) | |
fd978bf7 JS |
3714 | { |
3715 | struct bpf_reg_state *regs = state->regs, *reg; | |
3716 | int i; | |
3717 | ||
3718 | for (i = 0; i < MAX_BPF_REG; i++) | |
1b986589 | 3719 | if (regs[i].ref_obj_id == ref_obj_id) |
fd978bf7 JS |
3720 | mark_reg_unknown(env, regs, i); |
3721 | ||
3722 | bpf_for_each_spilled_reg(i, state, reg) { | |
3723 | if (!reg) | |
3724 | continue; | |
1b986589 | 3725 | if (reg->ref_obj_id == ref_obj_id) |
fd978bf7 JS |
3726 | __mark_reg_unknown(reg); |
3727 | } | |
3728 | } | |
3729 | ||
3730 | /* The pointer with the specified id has released its reference to kernel | |
3731 | * resources. Identify all copies of the same pointer and clear the reference. | |
3732 | */ | |
3733 | static int release_reference(struct bpf_verifier_env *env, | |
1b986589 | 3734 | int ref_obj_id) |
fd978bf7 JS |
3735 | { |
3736 | struct bpf_verifier_state *vstate = env->cur_state; | |
1b986589 | 3737 | int err; |
fd978bf7 JS |
3738 | int i; |
3739 | ||
1b986589 MKL |
3740 | err = release_reference_state(cur_func(env), ref_obj_id); |
3741 | if (err) | |
3742 | return err; | |
3743 | ||
fd978bf7 | 3744 | for (i = 0; i <= vstate->curframe; i++) |
1b986589 | 3745 | release_reg_references(env, vstate->frame[i], ref_obj_id); |
fd978bf7 | 3746 | |
1b986589 | 3747 | return 0; |
fd978bf7 JS |
3748 | } |
3749 | ||
f4d7e40a AS |
3750 | static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, |
3751 | int *insn_idx) | |
3752 | { | |
3753 | struct bpf_verifier_state *state = env->cur_state; | |
3754 | struct bpf_func_state *caller, *callee; | |
fd978bf7 | 3755 | int i, err, subprog, target_insn; |
f4d7e40a | 3756 | |
aada9ce6 | 3757 | if (state->curframe + 1 >= MAX_CALL_FRAMES) { |
f4d7e40a | 3758 | verbose(env, "the call stack of %d frames is too deep\n", |
aada9ce6 | 3759 | state->curframe + 2); |
f4d7e40a AS |
3760 | return -E2BIG; |
3761 | } | |
3762 | ||
3763 | target_insn = *insn_idx + insn->imm; | |
3764 | subprog = find_subprog(env, target_insn + 1); | |
3765 | if (subprog < 0) { | |
3766 | verbose(env, "verifier bug. No program starts at insn %d\n", | |
3767 | target_insn + 1); | |
3768 | return -EFAULT; | |
3769 | } | |
3770 | ||
3771 | caller = state->frame[state->curframe]; | |
3772 | if (state->frame[state->curframe + 1]) { | |
3773 | verbose(env, "verifier bug. Frame %d already allocated\n", | |
3774 | state->curframe + 1); | |
3775 | return -EFAULT; | |
3776 | } | |
3777 | ||
3778 | callee = kzalloc(sizeof(*callee), GFP_KERNEL); | |
3779 | if (!callee) | |
3780 | return -ENOMEM; | |
3781 | state->frame[state->curframe + 1] = callee; | |
3782 | ||
3783 | /* callee cannot access r0, r6 - r9 for reading and has to write | |
3784 | * into its own stack before reading from it. | |
3785 | * callee can read/write into caller's stack | |
3786 | */ | |
3787 | init_func_state(env, callee, | |
3788 | /* remember the callsite, it will be used by bpf_exit */ | |
3789 | *insn_idx /* callsite */, | |
3790 | state->curframe + 1 /* frameno within this callchain */, | |
f910cefa | 3791 | subprog /* subprog number within this prog */); |
f4d7e40a | 3792 | |
fd978bf7 JS |
3793 | /* Transfer references to the callee */ |
3794 | err = transfer_reference_state(callee, caller); | |
3795 | if (err) | |
3796 | return err; | |
3797 | ||
679c782d EC |
3798 | /* copy r1 - r5 args that callee can access. The copy includes parent |
3799 | * pointers, which connects us up to the liveness chain | |
3800 | */ | |
f4d7e40a AS |
3801 | for (i = BPF_REG_1; i <= BPF_REG_5; i++) |
3802 | callee->regs[i] = caller->regs[i]; | |
3803 | ||
679c782d | 3804 | /* after the call registers r0 - r5 were scratched */ |
f4d7e40a AS |
3805 | for (i = 0; i < CALLER_SAVED_REGS; i++) { |
3806 | mark_reg_not_init(env, caller->regs, caller_saved[i]); | |
3807 | check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK); | |
3808 | } | |
3809 | ||
3810 | /* only increment it after check_reg_arg() finished */ | |
3811 | state->curframe++; | |
3812 | ||
3813 | /* and go analyze first insn of the callee */ | |
3814 | *insn_idx = target_insn; | |
3815 | ||
06ee7115 | 3816 | if (env->log.level & BPF_LOG_LEVEL) { |
f4d7e40a AS |
3817 | verbose(env, "caller:\n"); |
3818 | print_verifier_state(env, caller); | |
3819 | verbose(env, "callee:\n"); | |
3820 | print_verifier_state(env, callee); | |
3821 | } | |
3822 | return 0; | |
3823 | } | |
3824 | ||
3825 | static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) | |
3826 | { | |
3827 | struct bpf_verifier_state *state = env->cur_state; | |
3828 | struct bpf_func_state *caller, *callee; | |
3829 | struct bpf_reg_state *r0; | |
fd978bf7 | 3830 | int err; |
f4d7e40a AS |
3831 | |
3832 | callee = state->frame[state->curframe]; | |
3833 | r0 = &callee->regs[BPF_REG_0]; | |
3834 | if (r0->type == PTR_TO_STACK) { | |
3835 | /* technically it's ok to return caller's stack pointer | |
3836 | * (or caller's caller's pointer) back to the caller, | |
3837 | * since these pointers are valid. Only current stack | |
3838 | * pointer will be invalid as soon as function exits, | |
3839 | * but let's be conservative | |
3840 | */ | |
3841 | verbose(env, "cannot return stack pointer to the caller\n"); | |
3842 | return -EINVAL; | |
3843 | } | |
3844 | ||
3845 | state->curframe--; | |
3846 | caller = state->frame[state->curframe]; | |
3847 | /* return to the caller whatever r0 had in the callee */ | |
3848 | caller->regs[BPF_REG_0] = *r0; | |
3849 | ||
fd978bf7 JS |
3850 | /* Transfer references to the caller */ |
3851 | err = transfer_reference_state(caller, callee); | |
3852 | if (err) | |
3853 | return err; | |
3854 | ||
f4d7e40a | 3855 | *insn_idx = callee->callsite + 1; |
06ee7115 | 3856 | if (env->log.level & BPF_LOG_LEVEL) { |
f4d7e40a AS |
3857 | verbose(env, "returning from callee:\n"); |
3858 | print_verifier_state(env, callee); | |
3859 | verbose(env, "to caller at %d:\n", *insn_idx); | |
3860 | print_verifier_state(env, caller); | |
3861 | } | |
3862 | /* clear everything in the callee */ | |
3863 | free_func_state(callee); | |
3864 | state->frame[state->curframe + 1] = NULL; | |
3865 | return 0; | |
3866 | } | |
3867 | ||
849fa506 YS |
3868 | static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type, |
3869 | int func_id, | |
3870 | struct bpf_call_arg_meta *meta) | |
3871 | { | |
3872 | struct bpf_reg_state *ret_reg = ®s[BPF_REG_0]; | |
3873 | ||
3874 | if (ret_type != RET_INTEGER || | |
3875 | (func_id != BPF_FUNC_get_stack && | |
3876 | func_id != BPF_FUNC_probe_read_str)) | |
3877 | return; | |
3878 | ||
3879 | ret_reg->smax_value = meta->msize_smax_value; | |
3880 | ret_reg->umax_value = meta->msize_umax_value; | |
3881 | __reg_deduce_bounds(ret_reg); | |
3882 | __reg_bound_offset(ret_reg); | |
3883 | } | |
3884 | ||
c93552c4 DB |
3885 | static int |
3886 | record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, | |
3887 | int func_id, int insn_idx) | |
3888 | { | |
3889 | struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx]; | |
591fe988 | 3890 | struct bpf_map *map = meta->map_ptr; |
c93552c4 DB |
3891 | |
3892 | if (func_id != BPF_FUNC_tail_call && | |
09772d92 DB |
3893 | func_id != BPF_FUNC_map_lookup_elem && |
3894 | func_id != BPF_FUNC_map_update_elem && | |
f1a2e44a MV |
3895 | func_id != BPF_FUNC_map_delete_elem && |
3896 | func_id != BPF_FUNC_map_push_elem && | |
3897 | func_id != BPF_FUNC_map_pop_elem && | |
3898 | func_id != BPF_FUNC_map_peek_elem) | |
c93552c4 | 3899 | return 0; |
09772d92 | 3900 | |
591fe988 | 3901 | if (map == NULL) { |
c93552c4 DB |
3902 | verbose(env, "kernel subsystem misconfigured verifier\n"); |
3903 | return -EINVAL; | |
3904 | } | |
3905 | ||
591fe988 DB |
3906 | /* In case of read-only, some additional restrictions |
3907 | * need to be applied in order to prevent altering the | |
3908 | * state of the map from program side. | |
3909 | */ | |
3910 | if ((map->map_flags & BPF_F_RDONLY_PROG) && | |
3911 | (func_id == BPF_FUNC_map_delete_elem || | |
3912 | func_id == BPF_FUNC_map_update_elem || | |
3913 | func_id == BPF_FUNC_map_push_elem || | |
3914 | func_id == BPF_FUNC_map_pop_elem)) { | |
3915 | verbose(env, "write into map forbidden\n"); | |
3916 | return -EACCES; | |
3917 | } | |
3918 | ||
c93552c4 DB |
3919 | if (!BPF_MAP_PTR(aux->map_state)) |
3920 | bpf_map_ptr_store(aux, meta->map_ptr, | |
3921 | meta->map_ptr->unpriv_array); | |
3922 | else if (BPF_MAP_PTR(aux->map_state) != meta->map_ptr) | |
3923 | bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON, | |
3924 | meta->map_ptr->unpriv_array); | |
3925 | return 0; | |
3926 | } | |
3927 | ||
fd978bf7 JS |
3928 | static int check_reference_leak(struct bpf_verifier_env *env) |
3929 | { | |
3930 | struct bpf_func_state *state = cur_func(env); | |
3931 | int i; | |
3932 | ||
3933 | for (i = 0; i < state->acquired_refs; i++) { | |
3934 | verbose(env, "Unreleased reference id=%d alloc_insn=%d\n", | |
3935 | state->refs[i].id, state->refs[i].insn_idx); | |
3936 | } | |
3937 | return state->acquired_refs ? -EINVAL : 0; | |
3938 | } | |
3939 | ||
f4d7e40a | 3940 | static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn_idx) |
17a52670 | 3941 | { |
17a52670 | 3942 | const struct bpf_func_proto *fn = NULL; |
638f5b90 | 3943 | struct bpf_reg_state *regs; |
33ff9823 | 3944 | struct bpf_call_arg_meta meta; |
969bf05e | 3945 | bool changes_data; |
17a52670 AS |
3946 | int i, err; |
3947 | ||
3948 | /* find function prototype */ | |
3949 | if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) { | |
61bd5218 JK |
3950 | verbose(env, "invalid func %s#%d\n", func_id_name(func_id), |
3951 | func_id); | |
17a52670 AS |
3952 | return -EINVAL; |
3953 | } | |
3954 | ||
00176a34 | 3955 | if (env->ops->get_func_proto) |
5e43f899 | 3956 | fn = env->ops->get_func_proto(func_id, env->prog); |
17a52670 | 3957 | if (!fn) { |
61bd5218 JK |
3958 | verbose(env, "unknown func %s#%d\n", func_id_name(func_id), |
3959 | func_id); | |
17a52670 AS |
3960 | return -EINVAL; |
3961 | } | |
3962 | ||
3963 | /* eBPF programs must be GPL compatible to use GPL-ed functions */ | |
24701ece | 3964 | if (!env->prog->gpl_compatible && fn->gpl_only) { |
3fe2867c | 3965 | verbose(env, "cannot call GPL-restricted function from non-GPL compatible program\n"); |
17a52670 AS |
3966 | return -EINVAL; |
3967 | } | |
3968 | ||
04514d13 | 3969 | /* With LD_ABS/IND some JITs save/restore skb from r1. */ |
17bedab2 | 3970 | changes_data = bpf_helper_changes_pkt_data(fn->func); |
04514d13 DB |
3971 | if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) { |
3972 | verbose(env, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n", | |
3973 | func_id_name(func_id), func_id); | |
3974 | return -EINVAL; | |
3975 | } | |
969bf05e | 3976 | |
33ff9823 | 3977 | memset(&meta, 0, sizeof(meta)); |
36bbef52 | 3978 | meta.pkt_access = fn->pkt_access; |
33ff9823 | 3979 | |
1b986589 | 3980 | err = check_func_proto(fn, func_id); |
435faee1 | 3981 | if (err) { |
61bd5218 | 3982 | verbose(env, "kernel subsystem misconfigured func %s#%d\n", |
ebb676da | 3983 | func_id_name(func_id), func_id); |
435faee1 DB |
3984 | return err; |
3985 | } | |
3986 | ||
d83525ca | 3987 | meta.func_id = func_id; |
17a52670 | 3988 | /* check args */ |
33ff9823 | 3989 | err = check_func_arg(env, BPF_REG_1, fn->arg1_type, &meta); |
17a52670 AS |
3990 | if (err) |
3991 | return err; | |
33ff9823 | 3992 | err = check_func_arg(env, BPF_REG_2, fn->arg2_type, &meta); |
17a52670 AS |
3993 | if (err) |
3994 | return err; | |
33ff9823 | 3995 | err = check_func_arg(env, BPF_REG_3, fn->arg3_type, &meta); |
17a52670 AS |
3996 | if (err) |
3997 | return err; | |
33ff9823 | 3998 | err = check_func_arg(env, BPF_REG_4, fn->arg4_type, &meta); |
17a52670 AS |
3999 | if (err) |
4000 | return err; | |
33ff9823 | 4001 | err = check_func_arg(env, BPF_REG_5, fn->arg5_type, &meta); |
17a52670 AS |
4002 | if (err) |
4003 | return err; | |
4004 | ||
c93552c4 DB |
4005 | err = record_func_map(env, &meta, func_id, insn_idx); |
4006 | if (err) | |
4007 | return err; | |
4008 | ||
435faee1 DB |
4009 | /* Mark slots with STACK_MISC in case of raw mode, stack offset |
4010 | * is inferred from register state. | |
4011 | */ | |
4012 | for (i = 0; i < meta.access_size; i++) { | |
ca369602 DB |
4013 | err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B, |
4014 | BPF_WRITE, -1, false); | |
435faee1 DB |
4015 | if (err) |
4016 | return err; | |
4017 | } | |
4018 | ||
fd978bf7 JS |
4019 | if (func_id == BPF_FUNC_tail_call) { |
4020 | err = check_reference_leak(env); | |
4021 | if (err) { | |
4022 | verbose(env, "tail_call would lead to reference leak\n"); | |
4023 | return err; | |
4024 | } | |
4025 | } else if (is_release_function(func_id)) { | |
1b986589 | 4026 | err = release_reference(env, meta.ref_obj_id); |
46f8bc92 MKL |
4027 | if (err) { |
4028 | verbose(env, "func %s#%d reference has not been acquired before\n", | |
4029 | func_id_name(func_id), func_id); | |
fd978bf7 | 4030 | return err; |
46f8bc92 | 4031 | } |
fd978bf7 JS |
4032 | } |
4033 | ||
638f5b90 | 4034 | regs = cur_regs(env); |
cd339431 RG |
4035 | |
4036 | /* check that flags argument in get_local_storage(map, flags) is 0, | |
4037 | * this is required because get_local_storage() can't return an error. | |
4038 | */ | |
4039 | if (func_id == BPF_FUNC_get_local_storage && | |
4040 | !register_is_null(®s[BPF_REG_2])) { | |
4041 | verbose(env, "get_local_storage() doesn't support non-zero flags\n"); | |
4042 | return -EINVAL; | |
4043 | } | |
4044 | ||
17a52670 | 4045 | /* reset caller saved regs */ |
dc503a8a | 4046 | for (i = 0; i < CALLER_SAVED_REGS; i++) { |
61bd5218 | 4047 | mark_reg_not_init(env, regs, caller_saved[i]); |
dc503a8a EC |
4048 | check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK); |
4049 | } | |
17a52670 | 4050 | |
5327ed3d JW |
4051 | /* helper call returns 64-bit value. */ |
4052 | regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG; | |
4053 | ||
dc503a8a | 4054 | /* update return register (already marked as written above) */ |
17a52670 | 4055 | if (fn->ret_type == RET_INTEGER) { |
f1174f77 | 4056 | /* sets type to SCALAR_VALUE */ |
61bd5218 | 4057 | mark_reg_unknown(env, regs, BPF_REG_0); |
17a52670 AS |
4058 | } else if (fn->ret_type == RET_VOID) { |
4059 | regs[BPF_REG_0].type = NOT_INIT; | |
3e6a4b3e RG |
4060 | } else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL || |
4061 | fn->ret_type == RET_PTR_TO_MAP_VALUE) { | |
f1174f77 | 4062 | /* There is no offset yet applied, variable or fixed */ |
61bd5218 | 4063 | mark_reg_known_zero(env, regs, BPF_REG_0); |
17a52670 AS |
4064 | /* remember map_ptr, so that check_map_access() |
4065 | * can check 'value_size' boundary of memory access | |
4066 | * to map element returned from bpf_map_lookup_elem() | |
4067 | */ | |
33ff9823 | 4068 | if (meta.map_ptr == NULL) { |
61bd5218 JK |
4069 | verbose(env, |
4070 | "kernel subsystem misconfigured verifier\n"); | |
17a52670 AS |
4071 | return -EINVAL; |
4072 | } | |
33ff9823 | 4073 | regs[BPF_REG_0].map_ptr = meta.map_ptr; |
4d31f301 DB |
4074 | if (fn->ret_type == RET_PTR_TO_MAP_VALUE) { |
4075 | regs[BPF_REG_0].type = PTR_TO_MAP_VALUE; | |
e16d2f1a AS |
4076 | if (map_value_has_spin_lock(meta.map_ptr)) |
4077 | regs[BPF_REG_0].id = ++env->id_gen; | |
4d31f301 DB |
4078 | } else { |
4079 | regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL; | |
4080 | regs[BPF_REG_0].id = ++env->id_gen; | |
4081 | } | |
c64b7983 JS |
4082 | } else if (fn->ret_type == RET_PTR_TO_SOCKET_OR_NULL) { |
4083 | mark_reg_known_zero(env, regs, BPF_REG_0); | |
4084 | regs[BPF_REG_0].type = PTR_TO_SOCKET_OR_NULL; | |
0f3adc28 | 4085 | regs[BPF_REG_0].id = ++env->id_gen; |
85a51f8c LB |
4086 | } else if (fn->ret_type == RET_PTR_TO_SOCK_COMMON_OR_NULL) { |
4087 | mark_reg_known_zero(env, regs, BPF_REG_0); | |
4088 | regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON_OR_NULL; | |
4089 | regs[BPF_REG_0].id = ++env->id_gen; | |
655a51e5 MKL |
4090 | } else if (fn->ret_type == RET_PTR_TO_TCP_SOCK_OR_NULL) { |
4091 | mark_reg_known_zero(env, regs, BPF_REG_0); | |
4092 | regs[BPF_REG_0].type = PTR_TO_TCP_SOCK_OR_NULL; | |
4093 | regs[BPF_REG_0].id = ++env->id_gen; | |
17a52670 | 4094 | } else { |
61bd5218 | 4095 | verbose(env, "unknown return type %d of func %s#%d\n", |
ebb676da | 4096 | fn->ret_type, func_id_name(func_id), func_id); |
17a52670 AS |
4097 | return -EINVAL; |
4098 | } | |
04fd61ab | 4099 | |
0f3adc28 | 4100 | if (is_ptr_cast_function(func_id)) { |
1b986589 MKL |
4101 | /* For release_reference() */ |
4102 | regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id; | |
0f3adc28 LB |
4103 | } else if (is_acquire_function(func_id)) { |
4104 | int id = acquire_reference_state(env, insn_idx); | |
4105 | ||
4106 | if (id < 0) | |
4107 | return id; | |
4108 | /* For mark_ptr_or_null_reg() */ | |
4109 | regs[BPF_REG_0].id = id; | |
4110 | /* For release_reference() */ | |
4111 | regs[BPF_REG_0].ref_obj_id = id; | |
4112 | } | |
1b986589 | 4113 | |
849fa506 YS |
4114 | do_refine_retval_range(regs, fn->ret_type, func_id, &meta); |
4115 | ||
61bd5218 | 4116 | err = check_map_func_compatibility(env, meta.map_ptr, func_id); |
35578d79 KX |
4117 | if (err) |
4118 | return err; | |
04fd61ab | 4119 | |
c195651e YS |
4120 | if (func_id == BPF_FUNC_get_stack && !env->prog->has_callchain_buf) { |
4121 | const char *err_str; | |
4122 | ||
4123 | #ifdef CONFIG_PERF_EVENTS | |
4124 | err = get_callchain_buffers(sysctl_perf_event_max_stack); | |
4125 | err_str = "cannot get callchain buffer for func %s#%d\n"; | |
4126 | #else | |
4127 | err = -ENOTSUPP; | |
4128 | err_str = "func %s#%d not supported without CONFIG_PERF_EVENTS\n"; | |
4129 | #endif | |
4130 | if (err) { | |
4131 | verbose(env, err_str, func_id_name(func_id), func_id); | |
4132 | return err; | |
4133 | } | |
4134 | ||
4135 | env->prog->has_callchain_buf = true; | |
4136 | } | |
4137 | ||
969bf05e AS |
4138 | if (changes_data) |
4139 | clear_all_pkt_pointers(env); | |
4140 | return 0; | |
4141 | } | |
4142 | ||
b03c9f9f EC |
4143 | static bool signed_add_overflows(s64 a, s64 b) |
4144 | { | |
4145 | /* Do the add in u64, where overflow is well-defined */ | |
4146 | s64 res = (s64)((u64)a + (u64)b); | |
4147 | ||
4148 | if (b < 0) | |
4149 | return res > a; | |
4150 | return res < a; | |
4151 | } | |
4152 | ||
4153 | static bool signed_sub_overflows(s64 a, s64 b) | |
4154 | { | |
4155 | /* Do the sub in u64, where overflow is well-defined */ | |
4156 | s64 res = (s64)((u64)a - (u64)b); | |
4157 | ||
4158 | if (b < 0) | |
4159 | return res < a; | |
4160 | return res > a; | |
969bf05e AS |
4161 | } |
4162 | ||
bb7f0f98 AS |
4163 | static bool check_reg_sane_offset(struct bpf_verifier_env *env, |
4164 | const struct bpf_reg_state *reg, | |
4165 | enum bpf_reg_type type) | |
4166 | { | |
4167 | bool known = tnum_is_const(reg->var_off); | |
4168 | s64 val = reg->var_off.value; | |
4169 | s64 smin = reg->smin_value; | |
4170 | ||
4171 | if (known && (val >= BPF_MAX_VAR_OFF || val <= -BPF_MAX_VAR_OFF)) { | |
4172 | verbose(env, "math between %s pointer and %lld is not allowed\n", | |
4173 | reg_type_str[type], val); | |
4174 | return false; | |
4175 | } | |
4176 | ||
4177 | if (reg->off >= BPF_MAX_VAR_OFF || reg->off <= -BPF_MAX_VAR_OFF) { | |
4178 | verbose(env, "%s pointer offset %d is not allowed\n", | |
4179 | reg_type_str[type], reg->off); | |
4180 | return false; | |
4181 | } | |
4182 | ||
4183 | if (smin == S64_MIN) { | |
4184 | verbose(env, "math between %s pointer and register with unbounded min value is not allowed\n", | |
4185 | reg_type_str[type]); | |
4186 | return false; | |
4187 | } | |
4188 | ||
4189 | if (smin >= BPF_MAX_VAR_OFF || smin <= -BPF_MAX_VAR_OFF) { | |
4190 | verbose(env, "value %lld makes %s pointer be out of bounds\n", | |
4191 | smin, reg_type_str[type]); | |
4192 | return false; | |
4193 | } | |
4194 | ||
4195 | return true; | |
4196 | } | |
4197 | ||
979d63d5 DB |
4198 | static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env) |
4199 | { | |
4200 | return &env->insn_aux_data[env->insn_idx]; | |
4201 | } | |
4202 | ||
4203 | static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, | |
4204 | u32 *ptr_limit, u8 opcode, bool off_is_neg) | |
4205 | { | |
4206 | bool mask_to_left = (opcode == BPF_ADD && off_is_neg) || | |
4207 | (opcode == BPF_SUB && !off_is_neg); | |
4208 | u32 off; | |
4209 | ||
4210 | switch (ptr_reg->type) { | |
4211 | case PTR_TO_STACK: | |
088ec26d AI |
4212 | /* Indirect variable offset stack access is prohibited in |
4213 | * unprivileged mode so it's not handled here. | |
4214 | */ | |
979d63d5 DB |
4215 | off = ptr_reg->off + ptr_reg->var_off.value; |
4216 | if (mask_to_left) | |
4217 | *ptr_limit = MAX_BPF_STACK + off; | |
4218 | else | |
4219 | *ptr_limit = -off; | |
4220 | return 0; | |
4221 | case PTR_TO_MAP_VALUE: | |
4222 | if (mask_to_left) { | |
4223 | *ptr_limit = ptr_reg->umax_value + ptr_reg->off; | |
4224 | } else { | |
4225 | off = ptr_reg->smin_value + ptr_reg->off; | |
4226 | *ptr_limit = ptr_reg->map_ptr->value_size - off; | |
4227 | } | |
4228 | return 0; | |
4229 | default: | |
4230 | return -EINVAL; | |
4231 | } | |
4232 | } | |
4233 | ||
d3bd7413 DB |
4234 | static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env, |
4235 | const struct bpf_insn *insn) | |
4236 | { | |
4237 | return env->allow_ptr_leaks || BPF_SRC(insn->code) == BPF_K; | |
4238 | } | |
4239 | ||
4240 | static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux, | |
4241 | u32 alu_state, u32 alu_limit) | |
4242 | { | |
4243 | /* If we arrived here from different branches with different | |
4244 | * state or limits to sanitize, then this won't work. | |
4245 | */ | |
4246 | if (aux->alu_state && | |
4247 | (aux->alu_state != alu_state || | |
4248 | aux->alu_limit != alu_limit)) | |
4249 | return -EACCES; | |
4250 | ||
4251 | /* Corresponding fixup done in fixup_bpf_calls(). */ | |
4252 | aux->alu_state = alu_state; | |
4253 | aux->alu_limit = alu_limit; | |
4254 | return 0; | |
4255 | } | |
4256 | ||
4257 | static int sanitize_val_alu(struct bpf_verifier_env *env, | |
4258 | struct bpf_insn *insn) | |
4259 | { | |
4260 | struct bpf_insn_aux_data *aux = cur_aux(env); | |
4261 | ||
4262 | if (can_skip_alu_sanitation(env, insn)) | |
4263 | return 0; | |
4264 | ||
4265 | return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0); | |
4266 | } | |
4267 | ||
979d63d5 DB |
4268 | static int sanitize_ptr_alu(struct bpf_verifier_env *env, |
4269 | struct bpf_insn *insn, | |
4270 | const struct bpf_reg_state *ptr_reg, | |
4271 | struct bpf_reg_state *dst_reg, | |
4272 | bool off_is_neg) | |
4273 | { | |
4274 | struct bpf_verifier_state *vstate = env->cur_state; | |
4275 | struct bpf_insn_aux_data *aux = cur_aux(env); | |
4276 | bool ptr_is_dst_reg = ptr_reg == dst_reg; | |
4277 | u8 opcode = BPF_OP(insn->code); | |
4278 | u32 alu_state, alu_limit; | |
4279 | struct bpf_reg_state tmp; | |
4280 | bool ret; | |
4281 | ||
d3bd7413 | 4282 | if (can_skip_alu_sanitation(env, insn)) |
979d63d5 DB |
4283 | return 0; |
4284 | ||
4285 | /* We already marked aux for masking from non-speculative | |
4286 | * paths, thus we got here in the first place. We only care | |
4287 | * to explore bad access from here. | |
4288 | */ | |
4289 | if (vstate->speculative) | |
4290 | goto do_sim; | |
4291 | ||
4292 | alu_state = off_is_neg ? BPF_ALU_NEG_VALUE : 0; | |
4293 | alu_state |= ptr_is_dst_reg ? | |
4294 | BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST; | |
4295 | ||
4296 | if (retrieve_ptr_limit(ptr_reg, &alu_limit, opcode, off_is_neg)) | |
4297 | return 0; | |
d3bd7413 | 4298 | if (update_alu_sanitation_state(aux, alu_state, alu_limit)) |
979d63d5 | 4299 | return -EACCES; |
979d63d5 DB |
4300 | do_sim: |
4301 | /* Simulate and find potential out-of-bounds access under | |
4302 | * speculative execution from truncation as a result of | |
4303 | * masking when off was not within expected range. If off | |
4304 | * sits in dst, then we temporarily need to move ptr there | |
4305 | * to simulate dst (== 0) +/-= ptr. Needed, for example, | |
4306 | * for cases where we use K-based arithmetic in one direction | |
4307 | * and truncated reg-based in the other in order to explore | |
4308 | * bad access. | |
4309 | */ | |
4310 | if (!ptr_is_dst_reg) { | |
4311 | tmp = *dst_reg; | |
4312 | *dst_reg = *ptr_reg; | |
4313 | } | |
4314 | ret = push_stack(env, env->insn_idx + 1, env->insn_idx, true); | |
0803278b | 4315 | if (!ptr_is_dst_reg && ret) |
979d63d5 DB |
4316 | *dst_reg = tmp; |
4317 | return !ret ? -EFAULT : 0; | |
4318 | } | |
4319 | ||
f1174f77 | 4320 | /* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off. |
f1174f77 EC |
4321 | * Caller should also handle BPF_MOV case separately. |
4322 | * If we return -EACCES, caller may want to try again treating pointer as a | |
4323 | * scalar. So we only emit a diagnostic if !env->allow_ptr_leaks. | |
4324 | */ | |
4325 | static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, | |
4326 | struct bpf_insn *insn, | |
4327 | const struct bpf_reg_state *ptr_reg, | |
4328 | const struct bpf_reg_state *off_reg) | |
969bf05e | 4329 | { |
f4d7e40a AS |
4330 | struct bpf_verifier_state *vstate = env->cur_state; |
4331 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
4332 | struct bpf_reg_state *regs = state->regs, *dst_reg; | |
f1174f77 | 4333 | bool known = tnum_is_const(off_reg->var_off); |
b03c9f9f EC |
4334 | s64 smin_val = off_reg->smin_value, smax_val = off_reg->smax_value, |
4335 | smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value; | |
4336 | u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value, | |
4337 | umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value; | |
9d7eceed | 4338 | u32 dst = insn->dst_reg, src = insn->src_reg; |
969bf05e | 4339 | u8 opcode = BPF_OP(insn->code); |
979d63d5 | 4340 | int ret; |
969bf05e | 4341 | |
f1174f77 | 4342 | dst_reg = ®s[dst]; |
969bf05e | 4343 | |
6f16101e DB |
4344 | if ((known && (smin_val != smax_val || umin_val != umax_val)) || |
4345 | smin_val > smax_val || umin_val > umax_val) { | |
4346 | /* Taint dst register if offset had invalid bounds derived from | |
4347 | * e.g. dead branches. | |
4348 | */ | |
4349 | __mark_reg_unknown(dst_reg); | |
4350 | return 0; | |
f1174f77 EC |
4351 | } |
4352 | ||
4353 | if (BPF_CLASS(insn->code) != BPF_ALU64) { | |
4354 | /* 32-bit ALU ops on pointers produce (meaningless) scalars */ | |
82abbf8d AS |
4355 | verbose(env, |
4356 | "R%d 32-bit pointer arithmetic prohibited\n", | |
4357 | dst); | |
f1174f77 | 4358 | return -EACCES; |
969bf05e AS |
4359 | } |
4360 | ||
aad2eeaf JS |
4361 | switch (ptr_reg->type) { |
4362 | case PTR_TO_MAP_VALUE_OR_NULL: | |
4363 | verbose(env, "R%d pointer arithmetic on %s prohibited, null-check it first\n", | |
4364 | dst, reg_type_str[ptr_reg->type]); | |
f1174f77 | 4365 | return -EACCES; |
aad2eeaf JS |
4366 | case CONST_PTR_TO_MAP: |
4367 | case PTR_TO_PACKET_END: | |
c64b7983 JS |
4368 | case PTR_TO_SOCKET: |
4369 | case PTR_TO_SOCKET_OR_NULL: | |
46f8bc92 MKL |
4370 | case PTR_TO_SOCK_COMMON: |
4371 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
655a51e5 MKL |
4372 | case PTR_TO_TCP_SOCK: |
4373 | case PTR_TO_TCP_SOCK_OR_NULL: | |
fada7fdc | 4374 | case PTR_TO_XDP_SOCK: |
aad2eeaf JS |
4375 | verbose(env, "R%d pointer arithmetic on %s prohibited\n", |
4376 | dst, reg_type_str[ptr_reg->type]); | |
f1174f77 | 4377 | return -EACCES; |
9d7eceed DB |
4378 | case PTR_TO_MAP_VALUE: |
4379 | if (!env->allow_ptr_leaks && !known && (smin_val < 0) != (smax_val < 0)) { | |
4380 | verbose(env, "R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n", | |
4381 | off_reg == dst_reg ? dst : src); | |
4382 | return -EACCES; | |
4383 | } | |
4384 | /* fall-through */ | |
aad2eeaf JS |
4385 | default: |
4386 | break; | |
f1174f77 EC |
4387 | } |
4388 | ||
4389 | /* In case of 'scalar += pointer', dst_reg inherits pointer type and id. | |
4390 | * The id may be overwritten later if we create a new variable offset. | |
969bf05e | 4391 | */ |
f1174f77 EC |
4392 | dst_reg->type = ptr_reg->type; |
4393 | dst_reg->id = ptr_reg->id; | |
969bf05e | 4394 | |
bb7f0f98 AS |
4395 | if (!check_reg_sane_offset(env, off_reg, ptr_reg->type) || |
4396 | !check_reg_sane_offset(env, ptr_reg, ptr_reg->type)) | |
4397 | return -EINVAL; | |
4398 | ||
f1174f77 EC |
4399 | switch (opcode) { |
4400 | case BPF_ADD: | |
979d63d5 DB |
4401 | ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0); |
4402 | if (ret < 0) { | |
4403 | verbose(env, "R%d tried to add from different maps or paths\n", dst); | |
4404 | return ret; | |
4405 | } | |
f1174f77 EC |
4406 | /* We can take a fixed offset as long as it doesn't overflow |
4407 | * the s32 'off' field | |
969bf05e | 4408 | */ |
b03c9f9f EC |
4409 | if (known && (ptr_reg->off + smin_val == |
4410 | (s64)(s32)(ptr_reg->off + smin_val))) { | |
f1174f77 | 4411 | /* pointer += K. Accumulate it into fixed offset */ |
b03c9f9f EC |
4412 | dst_reg->smin_value = smin_ptr; |
4413 | dst_reg->smax_value = smax_ptr; | |
4414 | dst_reg->umin_value = umin_ptr; | |
4415 | dst_reg->umax_value = umax_ptr; | |
f1174f77 | 4416 | dst_reg->var_off = ptr_reg->var_off; |
b03c9f9f | 4417 | dst_reg->off = ptr_reg->off + smin_val; |
0962590e | 4418 | dst_reg->raw = ptr_reg->raw; |
f1174f77 EC |
4419 | break; |
4420 | } | |
f1174f77 EC |
4421 | /* A new variable offset is created. Note that off_reg->off |
4422 | * == 0, since it's a scalar. | |
4423 | * dst_reg gets the pointer type and since some positive | |
4424 | * integer value was added to the pointer, give it a new 'id' | |
4425 | * if it's a PTR_TO_PACKET. | |
4426 | * this creates a new 'base' pointer, off_reg (variable) gets | |
4427 | * added into the variable offset, and we copy the fixed offset | |
4428 | * from ptr_reg. | |
969bf05e | 4429 | */ |
b03c9f9f EC |
4430 | if (signed_add_overflows(smin_ptr, smin_val) || |
4431 | signed_add_overflows(smax_ptr, smax_val)) { | |
4432 | dst_reg->smin_value = S64_MIN; | |
4433 | dst_reg->smax_value = S64_MAX; | |
4434 | } else { | |
4435 | dst_reg->smin_value = smin_ptr + smin_val; | |
4436 | dst_reg->smax_value = smax_ptr + smax_val; | |
4437 | } | |
4438 | if (umin_ptr + umin_val < umin_ptr || | |
4439 | umax_ptr + umax_val < umax_ptr) { | |
4440 | dst_reg->umin_value = 0; | |
4441 | dst_reg->umax_value = U64_MAX; | |
4442 | } else { | |
4443 | dst_reg->umin_value = umin_ptr + umin_val; | |
4444 | dst_reg->umax_value = umax_ptr + umax_val; | |
4445 | } | |
f1174f77 EC |
4446 | dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off); |
4447 | dst_reg->off = ptr_reg->off; | |
0962590e | 4448 | dst_reg->raw = ptr_reg->raw; |
de8f3a83 | 4449 | if (reg_is_pkt_pointer(ptr_reg)) { |
f1174f77 EC |
4450 | dst_reg->id = ++env->id_gen; |
4451 | /* something was added to pkt_ptr, set range to zero */ | |
0962590e | 4452 | dst_reg->raw = 0; |
f1174f77 EC |
4453 | } |
4454 | break; | |
4455 | case BPF_SUB: | |
979d63d5 DB |
4456 | ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0); |
4457 | if (ret < 0) { | |
4458 | verbose(env, "R%d tried to sub from different maps or paths\n", dst); | |
4459 | return ret; | |
4460 | } | |
f1174f77 EC |
4461 | if (dst_reg == off_reg) { |
4462 | /* scalar -= pointer. Creates an unknown scalar */ | |
82abbf8d AS |
4463 | verbose(env, "R%d tried to subtract pointer from scalar\n", |
4464 | dst); | |
f1174f77 EC |
4465 | return -EACCES; |
4466 | } | |
4467 | /* We don't allow subtraction from FP, because (according to | |
4468 | * test_verifier.c test "invalid fp arithmetic", JITs might not | |
4469 | * be able to deal with it. | |
969bf05e | 4470 | */ |
f1174f77 | 4471 | if (ptr_reg->type == PTR_TO_STACK) { |
82abbf8d AS |
4472 | verbose(env, "R%d subtraction from stack pointer prohibited\n", |
4473 | dst); | |
f1174f77 EC |
4474 | return -EACCES; |
4475 | } | |
b03c9f9f EC |
4476 | if (known && (ptr_reg->off - smin_val == |
4477 | (s64)(s32)(ptr_reg->off - smin_val))) { | |
f1174f77 | 4478 | /* pointer -= K. Subtract it from fixed offset */ |
b03c9f9f EC |
4479 | dst_reg->smin_value = smin_ptr; |
4480 | dst_reg->smax_value = smax_ptr; | |
4481 | dst_reg->umin_value = umin_ptr; | |
4482 | dst_reg->umax_value = umax_ptr; | |
f1174f77 EC |
4483 | dst_reg->var_off = ptr_reg->var_off; |
4484 | dst_reg->id = ptr_reg->id; | |
b03c9f9f | 4485 | dst_reg->off = ptr_reg->off - smin_val; |
0962590e | 4486 | dst_reg->raw = ptr_reg->raw; |
f1174f77 EC |
4487 | break; |
4488 | } | |
f1174f77 EC |
4489 | /* A new variable offset is created. If the subtrahend is known |
4490 | * nonnegative, then any reg->range we had before is still good. | |
969bf05e | 4491 | */ |
b03c9f9f EC |
4492 | if (signed_sub_overflows(smin_ptr, smax_val) || |
4493 | signed_sub_overflows(smax_ptr, smin_val)) { | |
4494 | /* Overflow possible, we know nothing */ | |
4495 | dst_reg->smin_value = S64_MIN; | |
4496 | dst_reg->smax_value = S64_MAX; | |
4497 | } else { | |
4498 | dst_reg->smin_value = smin_ptr - smax_val; | |
4499 | dst_reg->smax_value = smax_ptr - smin_val; | |
4500 | } | |
4501 | if (umin_ptr < umax_val) { | |
4502 | /* Overflow possible, we know nothing */ | |
4503 | dst_reg->umin_value = 0; | |
4504 | dst_reg->umax_value = U64_MAX; | |
4505 | } else { | |
4506 | /* Cannot overflow (as long as bounds are consistent) */ | |
4507 | dst_reg->umin_value = umin_ptr - umax_val; | |
4508 | dst_reg->umax_value = umax_ptr - umin_val; | |
4509 | } | |
f1174f77 EC |
4510 | dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off); |
4511 | dst_reg->off = ptr_reg->off; | |
0962590e | 4512 | dst_reg->raw = ptr_reg->raw; |
de8f3a83 | 4513 | if (reg_is_pkt_pointer(ptr_reg)) { |
f1174f77 EC |
4514 | dst_reg->id = ++env->id_gen; |
4515 | /* something was added to pkt_ptr, set range to zero */ | |
b03c9f9f | 4516 | if (smin_val < 0) |
0962590e | 4517 | dst_reg->raw = 0; |
43188702 | 4518 | } |
f1174f77 EC |
4519 | break; |
4520 | case BPF_AND: | |
4521 | case BPF_OR: | |
4522 | case BPF_XOR: | |
82abbf8d AS |
4523 | /* bitwise ops on pointers are troublesome, prohibit. */ |
4524 | verbose(env, "R%d bitwise operator %s on pointer prohibited\n", | |
4525 | dst, bpf_alu_string[opcode >> 4]); | |
f1174f77 EC |
4526 | return -EACCES; |
4527 | default: | |
4528 | /* other operators (e.g. MUL,LSH) produce non-pointer results */ | |
82abbf8d AS |
4529 | verbose(env, "R%d pointer arithmetic with %s operator prohibited\n", |
4530 | dst, bpf_alu_string[opcode >> 4]); | |
f1174f77 | 4531 | return -EACCES; |
43188702 JF |
4532 | } |
4533 | ||
bb7f0f98 AS |
4534 | if (!check_reg_sane_offset(env, dst_reg, ptr_reg->type)) |
4535 | return -EINVAL; | |
4536 | ||
b03c9f9f EC |
4537 | __update_reg_bounds(dst_reg); |
4538 | __reg_deduce_bounds(dst_reg); | |
4539 | __reg_bound_offset(dst_reg); | |
0d6303db DB |
4540 | |
4541 | /* For unprivileged we require that resulting offset must be in bounds | |
4542 | * in order to be able to sanitize access later on. | |
4543 | */ | |
e4298d25 DB |
4544 | if (!env->allow_ptr_leaks) { |
4545 | if (dst_reg->type == PTR_TO_MAP_VALUE && | |
4546 | check_map_access(env, dst, dst_reg->off, 1, false)) { | |
4547 | verbose(env, "R%d pointer arithmetic of map value goes out of range, " | |
4548 | "prohibited for !root\n", dst); | |
4549 | return -EACCES; | |
4550 | } else if (dst_reg->type == PTR_TO_STACK && | |
4551 | check_stack_access(env, dst_reg, dst_reg->off + | |
4552 | dst_reg->var_off.value, 1)) { | |
4553 | verbose(env, "R%d stack pointer arithmetic goes out of range, " | |
4554 | "prohibited for !root\n", dst); | |
4555 | return -EACCES; | |
4556 | } | |
0d6303db DB |
4557 | } |
4558 | ||
43188702 JF |
4559 | return 0; |
4560 | } | |
4561 | ||
468f6eaf JH |
4562 | /* WARNING: This function does calculations on 64-bit values, but the actual |
4563 | * execution may occur on 32-bit values. Therefore, things like bitshifts | |
4564 | * need extra checks in the 32-bit case. | |
4565 | */ | |
f1174f77 EC |
4566 | static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, |
4567 | struct bpf_insn *insn, | |
4568 | struct bpf_reg_state *dst_reg, | |
4569 | struct bpf_reg_state src_reg) | |
969bf05e | 4570 | { |
638f5b90 | 4571 | struct bpf_reg_state *regs = cur_regs(env); |
48461135 | 4572 | u8 opcode = BPF_OP(insn->code); |
f1174f77 | 4573 | bool src_known, dst_known; |
b03c9f9f EC |
4574 | s64 smin_val, smax_val; |
4575 | u64 umin_val, umax_val; | |
468f6eaf | 4576 | u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32; |
d3bd7413 DB |
4577 | u32 dst = insn->dst_reg; |
4578 | int ret; | |
48461135 | 4579 | |
b799207e JH |
4580 | if (insn_bitness == 32) { |
4581 | /* Relevant for 32-bit RSH: Information can propagate towards | |
4582 | * LSB, so it isn't sufficient to only truncate the output to | |
4583 | * 32 bits. | |
4584 | */ | |
4585 | coerce_reg_to_size(dst_reg, 4); | |
4586 | coerce_reg_to_size(&src_reg, 4); | |
4587 | } | |
4588 | ||
b03c9f9f EC |
4589 | smin_val = src_reg.smin_value; |
4590 | smax_val = src_reg.smax_value; | |
4591 | umin_val = src_reg.umin_value; | |
4592 | umax_val = src_reg.umax_value; | |
f1174f77 EC |
4593 | src_known = tnum_is_const(src_reg.var_off); |
4594 | dst_known = tnum_is_const(dst_reg->var_off); | |
f23cc643 | 4595 | |
6f16101e DB |
4596 | if ((src_known && (smin_val != smax_val || umin_val != umax_val)) || |
4597 | smin_val > smax_val || umin_val > umax_val) { | |
4598 | /* Taint dst register if offset had invalid bounds derived from | |
4599 | * e.g. dead branches. | |
4600 | */ | |
4601 | __mark_reg_unknown(dst_reg); | |
4602 | return 0; | |
4603 | } | |
4604 | ||
bb7f0f98 AS |
4605 | if (!src_known && |
4606 | opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) { | |
4607 | __mark_reg_unknown(dst_reg); | |
4608 | return 0; | |
4609 | } | |
4610 | ||
48461135 JB |
4611 | switch (opcode) { |
4612 | case BPF_ADD: | |
d3bd7413 DB |
4613 | ret = sanitize_val_alu(env, insn); |
4614 | if (ret < 0) { | |
4615 | verbose(env, "R%d tried to add from different pointers or scalars\n", dst); | |
4616 | return ret; | |
4617 | } | |
b03c9f9f EC |
4618 | if (signed_add_overflows(dst_reg->smin_value, smin_val) || |
4619 | signed_add_overflows(dst_reg->smax_value, smax_val)) { | |
4620 | dst_reg->smin_value = S64_MIN; | |
4621 | dst_reg->smax_value = S64_MAX; | |
4622 | } else { | |
4623 | dst_reg->smin_value += smin_val; | |
4624 | dst_reg->smax_value += smax_val; | |
4625 | } | |
4626 | if (dst_reg->umin_value + umin_val < umin_val || | |
4627 | dst_reg->umax_value + umax_val < umax_val) { | |
4628 | dst_reg->umin_value = 0; | |
4629 | dst_reg->umax_value = U64_MAX; | |
4630 | } else { | |
4631 | dst_reg->umin_value += umin_val; | |
4632 | dst_reg->umax_value += umax_val; | |
4633 | } | |
f1174f77 | 4634 | dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off); |
48461135 JB |
4635 | break; |
4636 | case BPF_SUB: | |
d3bd7413 DB |
4637 | ret = sanitize_val_alu(env, insn); |
4638 | if (ret < 0) { | |
4639 | verbose(env, "R%d tried to sub from different pointers or scalars\n", dst); | |
4640 | return ret; | |
4641 | } | |
b03c9f9f EC |
4642 | if (signed_sub_overflows(dst_reg->smin_value, smax_val) || |
4643 | signed_sub_overflows(dst_reg->smax_value, smin_val)) { | |
4644 | /* Overflow possible, we know nothing */ | |
4645 | dst_reg->smin_value = S64_MIN; | |
4646 | dst_reg->smax_value = S64_MAX; | |
4647 | } else { | |
4648 | dst_reg->smin_value -= smax_val; | |
4649 | dst_reg->smax_value -= smin_val; | |
4650 | } | |
4651 | if (dst_reg->umin_value < umax_val) { | |
4652 | /* Overflow possible, we know nothing */ | |
4653 | dst_reg->umin_value = 0; | |
4654 | dst_reg->umax_value = U64_MAX; | |
4655 | } else { | |
4656 | /* Cannot overflow (as long as bounds are consistent) */ | |
4657 | dst_reg->umin_value -= umax_val; | |
4658 | dst_reg->umax_value -= umin_val; | |
4659 | } | |
f1174f77 | 4660 | dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off); |
48461135 JB |
4661 | break; |
4662 | case BPF_MUL: | |
b03c9f9f EC |
4663 | dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off); |
4664 | if (smin_val < 0 || dst_reg->smin_value < 0) { | |
f1174f77 | 4665 | /* Ain't nobody got time to multiply that sign */ |
b03c9f9f EC |
4666 | __mark_reg_unbounded(dst_reg); |
4667 | __update_reg_bounds(dst_reg); | |
f1174f77 EC |
4668 | break; |
4669 | } | |
b03c9f9f EC |
4670 | /* Both values are positive, so we can work with unsigned and |
4671 | * copy the result to signed (unless it exceeds S64_MAX). | |
f1174f77 | 4672 | */ |
b03c9f9f EC |
4673 | if (umax_val > U32_MAX || dst_reg->umax_value > U32_MAX) { |
4674 | /* Potential overflow, we know nothing */ | |
4675 | __mark_reg_unbounded(dst_reg); | |
4676 | /* (except what we can learn from the var_off) */ | |
4677 | __update_reg_bounds(dst_reg); | |
4678 | break; | |
4679 | } | |
4680 | dst_reg->umin_value *= umin_val; | |
4681 | dst_reg->umax_value *= umax_val; | |
4682 | if (dst_reg->umax_value > S64_MAX) { | |
4683 | /* Overflow possible, we know nothing */ | |
4684 | dst_reg->smin_value = S64_MIN; | |
4685 | dst_reg->smax_value = S64_MAX; | |
4686 | } else { | |
4687 | dst_reg->smin_value = dst_reg->umin_value; | |
4688 | dst_reg->smax_value = dst_reg->umax_value; | |
4689 | } | |
48461135 JB |
4690 | break; |
4691 | case BPF_AND: | |
f1174f77 | 4692 | if (src_known && dst_known) { |
b03c9f9f EC |
4693 | __mark_reg_known(dst_reg, dst_reg->var_off.value & |
4694 | src_reg.var_off.value); | |
f1174f77 EC |
4695 | break; |
4696 | } | |
b03c9f9f EC |
4697 | /* We get our minimum from the var_off, since that's inherently |
4698 | * bitwise. Our maximum is the minimum of the operands' maxima. | |
f23cc643 | 4699 | */ |
f1174f77 | 4700 | dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg.var_off); |
b03c9f9f EC |
4701 | dst_reg->umin_value = dst_reg->var_off.value; |
4702 | dst_reg->umax_value = min(dst_reg->umax_value, umax_val); | |
4703 | if (dst_reg->smin_value < 0 || smin_val < 0) { | |
4704 | /* Lose signed bounds when ANDing negative numbers, | |
4705 | * ain't nobody got time for that. | |
4706 | */ | |
4707 | dst_reg->smin_value = S64_MIN; | |
4708 | dst_reg->smax_value = S64_MAX; | |
4709 | } else { | |
4710 | /* ANDing two positives gives a positive, so safe to | |
4711 | * cast result into s64. | |
4712 | */ | |
4713 | dst_reg->smin_value = dst_reg->umin_value; | |
4714 | dst_reg->smax_value = dst_reg->umax_value; | |
4715 | } | |
4716 | /* We may learn something more from the var_off */ | |
4717 | __update_reg_bounds(dst_reg); | |
f1174f77 EC |
4718 | break; |
4719 | case BPF_OR: | |
4720 | if (src_known && dst_known) { | |
b03c9f9f EC |
4721 | __mark_reg_known(dst_reg, dst_reg->var_off.value | |
4722 | src_reg.var_off.value); | |
f1174f77 EC |
4723 | break; |
4724 | } | |
b03c9f9f EC |
4725 | /* We get our maximum from the var_off, and our minimum is the |
4726 | * maximum of the operands' minima | |
f1174f77 EC |
4727 | */ |
4728 | dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg.var_off); | |
b03c9f9f EC |
4729 | dst_reg->umin_value = max(dst_reg->umin_value, umin_val); |
4730 | dst_reg->umax_value = dst_reg->var_off.value | | |
4731 | dst_reg->var_off.mask; | |
4732 | if (dst_reg->smin_value < 0 || smin_val < 0) { | |
4733 | /* Lose signed bounds when ORing negative numbers, | |
4734 | * ain't nobody got time for that. | |
4735 | */ | |
4736 | dst_reg->smin_value = S64_MIN; | |
4737 | dst_reg->smax_value = S64_MAX; | |
f1174f77 | 4738 | } else { |
b03c9f9f EC |
4739 | /* ORing two positives gives a positive, so safe to |
4740 | * cast result into s64. | |
4741 | */ | |
4742 | dst_reg->smin_value = dst_reg->umin_value; | |
4743 | dst_reg->smax_value = dst_reg->umax_value; | |
f1174f77 | 4744 | } |
b03c9f9f EC |
4745 | /* We may learn something more from the var_off */ |
4746 | __update_reg_bounds(dst_reg); | |
48461135 JB |
4747 | break; |
4748 | case BPF_LSH: | |
468f6eaf JH |
4749 | if (umax_val >= insn_bitness) { |
4750 | /* Shifts greater than 31 or 63 are undefined. | |
4751 | * This includes shifts by a negative number. | |
b03c9f9f | 4752 | */ |
61bd5218 | 4753 | mark_reg_unknown(env, regs, insn->dst_reg); |
f1174f77 EC |
4754 | break; |
4755 | } | |
b03c9f9f EC |
4756 | /* We lose all sign bit information (except what we can pick |
4757 | * up from var_off) | |
48461135 | 4758 | */ |
b03c9f9f EC |
4759 | dst_reg->smin_value = S64_MIN; |
4760 | dst_reg->smax_value = S64_MAX; | |
4761 | /* If we might shift our top bit out, then we know nothing */ | |
4762 | if (dst_reg->umax_value > 1ULL << (63 - umax_val)) { | |
4763 | dst_reg->umin_value = 0; | |
4764 | dst_reg->umax_value = U64_MAX; | |
d1174416 | 4765 | } else { |
b03c9f9f EC |
4766 | dst_reg->umin_value <<= umin_val; |
4767 | dst_reg->umax_value <<= umax_val; | |
d1174416 | 4768 | } |
afbe1a5b | 4769 | dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val); |
b03c9f9f EC |
4770 | /* We may learn something more from the var_off */ |
4771 | __update_reg_bounds(dst_reg); | |
48461135 JB |
4772 | break; |
4773 | case BPF_RSH: | |
468f6eaf JH |
4774 | if (umax_val >= insn_bitness) { |
4775 | /* Shifts greater than 31 or 63 are undefined. | |
4776 | * This includes shifts by a negative number. | |
b03c9f9f | 4777 | */ |
61bd5218 | 4778 | mark_reg_unknown(env, regs, insn->dst_reg); |
f1174f77 EC |
4779 | break; |
4780 | } | |
4374f256 EC |
4781 | /* BPF_RSH is an unsigned shift. If the value in dst_reg might |
4782 | * be negative, then either: | |
4783 | * 1) src_reg might be zero, so the sign bit of the result is | |
4784 | * unknown, so we lose our signed bounds | |
4785 | * 2) it's known negative, thus the unsigned bounds capture the | |
4786 | * signed bounds | |
4787 | * 3) the signed bounds cross zero, so they tell us nothing | |
4788 | * about the result | |
4789 | * If the value in dst_reg is known nonnegative, then again the | |
4790 | * unsigned bounts capture the signed bounds. | |
4791 | * Thus, in all cases it suffices to blow away our signed bounds | |
4792 | * and rely on inferring new ones from the unsigned bounds and | |
4793 | * var_off of the result. | |
4794 | */ | |
4795 | dst_reg->smin_value = S64_MIN; | |
4796 | dst_reg->smax_value = S64_MAX; | |
afbe1a5b | 4797 | dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val); |
b03c9f9f EC |
4798 | dst_reg->umin_value >>= umax_val; |
4799 | dst_reg->umax_value >>= umin_val; | |
4800 | /* We may learn something more from the var_off */ | |
4801 | __update_reg_bounds(dst_reg); | |
48461135 | 4802 | break; |
9cbe1f5a YS |
4803 | case BPF_ARSH: |
4804 | if (umax_val >= insn_bitness) { | |
4805 | /* Shifts greater than 31 or 63 are undefined. | |
4806 | * This includes shifts by a negative number. | |
4807 | */ | |
4808 | mark_reg_unknown(env, regs, insn->dst_reg); | |
4809 | break; | |
4810 | } | |
4811 | ||
4812 | /* Upon reaching here, src_known is true and | |
4813 | * umax_val is equal to umin_val. | |
4814 | */ | |
4815 | dst_reg->smin_value >>= umin_val; | |
4816 | dst_reg->smax_value >>= umin_val; | |
4817 | dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val); | |
4818 | ||
4819 | /* blow away the dst_reg umin_value/umax_value and rely on | |
4820 | * dst_reg var_off to refine the result. | |
4821 | */ | |
4822 | dst_reg->umin_value = 0; | |
4823 | dst_reg->umax_value = U64_MAX; | |
4824 | __update_reg_bounds(dst_reg); | |
4825 | break; | |
48461135 | 4826 | default: |
61bd5218 | 4827 | mark_reg_unknown(env, regs, insn->dst_reg); |
48461135 JB |
4828 | break; |
4829 | } | |
4830 | ||
468f6eaf JH |
4831 | if (BPF_CLASS(insn->code) != BPF_ALU64) { |
4832 | /* 32-bit ALU ops are (32,32)->32 */ | |
4833 | coerce_reg_to_size(dst_reg, 4); | |
468f6eaf JH |
4834 | } |
4835 | ||
b03c9f9f EC |
4836 | __reg_deduce_bounds(dst_reg); |
4837 | __reg_bound_offset(dst_reg); | |
f1174f77 EC |
4838 | return 0; |
4839 | } | |
4840 | ||
4841 | /* Handles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max | |
4842 | * and var_off. | |
4843 | */ | |
4844 | static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, | |
4845 | struct bpf_insn *insn) | |
4846 | { | |
f4d7e40a AS |
4847 | struct bpf_verifier_state *vstate = env->cur_state; |
4848 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; | |
4849 | struct bpf_reg_state *regs = state->regs, *dst_reg, *src_reg; | |
f1174f77 EC |
4850 | struct bpf_reg_state *ptr_reg = NULL, off_reg = {0}; |
4851 | u8 opcode = BPF_OP(insn->code); | |
b5dc0163 | 4852 | int err; |
f1174f77 EC |
4853 | |
4854 | dst_reg = ®s[insn->dst_reg]; | |
f1174f77 EC |
4855 | src_reg = NULL; |
4856 | if (dst_reg->type != SCALAR_VALUE) | |
4857 | ptr_reg = dst_reg; | |
4858 | if (BPF_SRC(insn->code) == BPF_X) { | |
4859 | src_reg = ®s[insn->src_reg]; | |
f1174f77 EC |
4860 | if (src_reg->type != SCALAR_VALUE) { |
4861 | if (dst_reg->type != SCALAR_VALUE) { | |
4862 | /* Combining two pointers by any ALU op yields | |
82abbf8d AS |
4863 | * an arbitrary scalar. Disallow all math except |
4864 | * pointer subtraction | |
f1174f77 | 4865 | */ |
dd066823 | 4866 | if (opcode == BPF_SUB && env->allow_ptr_leaks) { |
82abbf8d AS |
4867 | mark_reg_unknown(env, regs, insn->dst_reg); |
4868 | return 0; | |
f1174f77 | 4869 | } |
82abbf8d AS |
4870 | verbose(env, "R%d pointer %s pointer prohibited\n", |
4871 | insn->dst_reg, | |
4872 | bpf_alu_string[opcode >> 4]); | |
4873 | return -EACCES; | |
f1174f77 EC |
4874 | } else { |
4875 | /* scalar += pointer | |
4876 | * This is legal, but we have to reverse our | |
4877 | * src/dest handling in computing the range | |
4878 | */ | |
b5dc0163 AS |
4879 | err = mark_chain_precision(env, insn->dst_reg); |
4880 | if (err) | |
4881 | return err; | |
82abbf8d AS |
4882 | return adjust_ptr_min_max_vals(env, insn, |
4883 | src_reg, dst_reg); | |
f1174f77 EC |
4884 | } |
4885 | } else if (ptr_reg) { | |
4886 | /* pointer += scalar */ | |
b5dc0163 AS |
4887 | err = mark_chain_precision(env, insn->src_reg); |
4888 | if (err) | |
4889 | return err; | |
82abbf8d AS |
4890 | return adjust_ptr_min_max_vals(env, insn, |
4891 | dst_reg, src_reg); | |
f1174f77 EC |
4892 | } |
4893 | } else { | |
4894 | /* Pretend the src is a reg with a known value, since we only | |
4895 | * need to be able to read from this state. | |
4896 | */ | |
4897 | off_reg.type = SCALAR_VALUE; | |
b03c9f9f | 4898 | __mark_reg_known(&off_reg, insn->imm); |
f1174f77 | 4899 | src_reg = &off_reg; |
82abbf8d AS |
4900 | if (ptr_reg) /* pointer += K */ |
4901 | return adjust_ptr_min_max_vals(env, insn, | |
4902 | ptr_reg, src_reg); | |
f1174f77 EC |
4903 | } |
4904 | ||
4905 | /* Got here implies adding two SCALAR_VALUEs */ | |
4906 | if (WARN_ON_ONCE(ptr_reg)) { | |
f4d7e40a | 4907 | print_verifier_state(env, state); |
61bd5218 | 4908 | verbose(env, "verifier internal error: unexpected ptr_reg\n"); |
f1174f77 EC |
4909 | return -EINVAL; |
4910 | } | |
4911 | if (WARN_ON(!src_reg)) { | |
f4d7e40a | 4912 | print_verifier_state(env, state); |
61bd5218 | 4913 | verbose(env, "verifier internal error: no src_reg\n"); |
f1174f77 EC |
4914 | return -EINVAL; |
4915 | } | |
4916 | return adjust_scalar_min_max_vals(env, insn, dst_reg, *src_reg); | |
48461135 JB |
4917 | } |
4918 | ||
17a52670 | 4919 | /* check validity of 32-bit and 64-bit arithmetic operations */ |
58e2af8b | 4920 | static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) |
17a52670 | 4921 | { |
638f5b90 | 4922 | struct bpf_reg_state *regs = cur_regs(env); |
17a52670 AS |
4923 | u8 opcode = BPF_OP(insn->code); |
4924 | int err; | |
4925 | ||
4926 | if (opcode == BPF_END || opcode == BPF_NEG) { | |
4927 | if (opcode == BPF_NEG) { | |
4928 | if (BPF_SRC(insn->code) != 0 || | |
4929 | insn->src_reg != BPF_REG_0 || | |
4930 | insn->off != 0 || insn->imm != 0) { | |
61bd5218 | 4931 | verbose(env, "BPF_NEG uses reserved fields\n"); |
17a52670 AS |
4932 | return -EINVAL; |
4933 | } | |
4934 | } else { | |
4935 | if (insn->src_reg != BPF_REG_0 || insn->off != 0 || | |
e67b8a68 EC |
4936 | (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) || |
4937 | BPF_CLASS(insn->code) == BPF_ALU64) { | |
61bd5218 | 4938 | verbose(env, "BPF_END uses reserved fields\n"); |
17a52670 AS |
4939 | return -EINVAL; |
4940 | } | |
4941 | } | |
4942 | ||
4943 | /* check src operand */ | |
dc503a8a | 4944 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
4945 | if (err) |
4946 | return err; | |
4947 | ||
1be7f75d | 4948 | if (is_pointer_value(env, insn->dst_reg)) { |
61bd5218 | 4949 | verbose(env, "R%d pointer arithmetic prohibited\n", |
1be7f75d AS |
4950 | insn->dst_reg); |
4951 | return -EACCES; | |
4952 | } | |
4953 | ||
17a52670 | 4954 | /* check dest operand */ |
dc503a8a | 4955 | err = check_reg_arg(env, insn->dst_reg, DST_OP); |
17a52670 AS |
4956 | if (err) |
4957 | return err; | |
4958 | ||
4959 | } else if (opcode == BPF_MOV) { | |
4960 | ||
4961 | if (BPF_SRC(insn->code) == BPF_X) { | |
4962 | if (insn->imm != 0 || insn->off != 0) { | |
61bd5218 | 4963 | verbose(env, "BPF_MOV uses reserved fields\n"); |
17a52670 AS |
4964 | return -EINVAL; |
4965 | } | |
4966 | ||
4967 | /* check src operand */ | |
dc503a8a | 4968 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
4969 | if (err) |
4970 | return err; | |
4971 | } else { | |
4972 | if (insn->src_reg != BPF_REG_0 || insn->off != 0) { | |
61bd5218 | 4973 | verbose(env, "BPF_MOV uses reserved fields\n"); |
17a52670 AS |
4974 | return -EINVAL; |
4975 | } | |
4976 | } | |
4977 | ||
fbeb1603 AF |
4978 | /* check dest operand, mark as required later */ |
4979 | err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); | |
17a52670 AS |
4980 | if (err) |
4981 | return err; | |
4982 | ||
4983 | if (BPF_SRC(insn->code) == BPF_X) { | |
e434b8cd JW |
4984 | struct bpf_reg_state *src_reg = regs + insn->src_reg; |
4985 | struct bpf_reg_state *dst_reg = regs + insn->dst_reg; | |
4986 | ||
17a52670 AS |
4987 | if (BPF_CLASS(insn->code) == BPF_ALU64) { |
4988 | /* case: R1 = R2 | |
4989 | * copy register state to dest reg | |
4990 | */ | |
e434b8cd JW |
4991 | *dst_reg = *src_reg; |
4992 | dst_reg->live |= REG_LIVE_WRITTEN; | |
5327ed3d | 4993 | dst_reg->subreg_def = DEF_NOT_SUBREG; |
17a52670 | 4994 | } else { |
f1174f77 | 4995 | /* R1 = (u32) R2 */ |
1be7f75d | 4996 | if (is_pointer_value(env, insn->src_reg)) { |
61bd5218 JK |
4997 | verbose(env, |
4998 | "R%d partial copy of pointer\n", | |
1be7f75d AS |
4999 | insn->src_reg); |
5000 | return -EACCES; | |
e434b8cd JW |
5001 | } else if (src_reg->type == SCALAR_VALUE) { |
5002 | *dst_reg = *src_reg; | |
5003 | dst_reg->live |= REG_LIVE_WRITTEN; | |
5327ed3d | 5004 | dst_reg->subreg_def = env->insn_idx + 1; |
e434b8cd JW |
5005 | } else { |
5006 | mark_reg_unknown(env, regs, | |
5007 | insn->dst_reg); | |
1be7f75d | 5008 | } |
e434b8cd | 5009 | coerce_reg_to_size(dst_reg, 4); |
17a52670 AS |
5010 | } |
5011 | } else { | |
5012 | /* case: R = imm | |
5013 | * remember the value we stored into this reg | |
5014 | */ | |
fbeb1603 AF |
5015 | /* clear any state __mark_reg_known doesn't set */ |
5016 | mark_reg_unknown(env, regs, insn->dst_reg); | |
f1174f77 | 5017 | regs[insn->dst_reg].type = SCALAR_VALUE; |
95a762e2 JH |
5018 | if (BPF_CLASS(insn->code) == BPF_ALU64) { |
5019 | __mark_reg_known(regs + insn->dst_reg, | |
5020 | insn->imm); | |
5021 | } else { | |
5022 | __mark_reg_known(regs + insn->dst_reg, | |
5023 | (u32)insn->imm); | |
5024 | } | |
17a52670 AS |
5025 | } |
5026 | ||
5027 | } else if (opcode > BPF_END) { | |
61bd5218 | 5028 | verbose(env, "invalid BPF_ALU opcode %x\n", opcode); |
17a52670 AS |
5029 | return -EINVAL; |
5030 | ||
5031 | } else { /* all other ALU ops: and, sub, xor, add, ... */ | |
5032 | ||
17a52670 AS |
5033 | if (BPF_SRC(insn->code) == BPF_X) { |
5034 | if (insn->imm != 0 || insn->off != 0) { | |
61bd5218 | 5035 | verbose(env, "BPF_ALU uses reserved fields\n"); |
17a52670 AS |
5036 | return -EINVAL; |
5037 | } | |
5038 | /* check src1 operand */ | |
dc503a8a | 5039 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
5040 | if (err) |
5041 | return err; | |
5042 | } else { | |
5043 | if (insn->src_reg != BPF_REG_0 || insn->off != 0) { | |
61bd5218 | 5044 | verbose(env, "BPF_ALU uses reserved fields\n"); |
17a52670 AS |
5045 | return -EINVAL; |
5046 | } | |
5047 | } | |
5048 | ||
5049 | /* check src2 operand */ | |
dc503a8a | 5050 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
5051 | if (err) |
5052 | return err; | |
5053 | ||
5054 | if ((opcode == BPF_MOD || opcode == BPF_DIV) && | |
5055 | BPF_SRC(insn->code) == BPF_K && insn->imm == 0) { | |
61bd5218 | 5056 | verbose(env, "div by zero\n"); |
17a52670 AS |
5057 | return -EINVAL; |
5058 | } | |
5059 | ||
229394e8 RV |
5060 | if ((opcode == BPF_LSH || opcode == BPF_RSH || |
5061 | opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) { | |
5062 | int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32; | |
5063 | ||
5064 | if (insn->imm < 0 || insn->imm >= size) { | |
61bd5218 | 5065 | verbose(env, "invalid shift %d\n", insn->imm); |
229394e8 RV |
5066 | return -EINVAL; |
5067 | } | |
5068 | } | |
5069 | ||
1a0dc1ac | 5070 | /* check dest operand */ |
dc503a8a | 5071 | err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); |
1a0dc1ac AS |
5072 | if (err) |
5073 | return err; | |
5074 | ||
f1174f77 | 5075 | return adjust_reg_min_max_vals(env, insn); |
17a52670 AS |
5076 | } |
5077 | ||
5078 | return 0; | |
5079 | } | |
5080 | ||
c6a9efa1 PC |
5081 | static void __find_good_pkt_pointers(struct bpf_func_state *state, |
5082 | struct bpf_reg_state *dst_reg, | |
5083 | enum bpf_reg_type type, u16 new_range) | |
5084 | { | |
5085 | struct bpf_reg_state *reg; | |
5086 | int i; | |
5087 | ||
5088 | for (i = 0; i < MAX_BPF_REG; i++) { | |
5089 | reg = &state->regs[i]; | |
5090 | if (reg->type == type && reg->id == dst_reg->id) | |
5091 | /* keep the maximum range already checked */ | |
5092 | reg->range = max(reg->range, new_range); | |
5093 | } | |
5094 | ||
5095 | bpf_for_each_spilled_reg(i, state, reg) { | |
5096 | if (!reg) | |
5097 | continue; | |
5098 | if (reg->type == type && reg->id == dst_reg->id) | |
5099 | reg->range = max(reg->range, new_range); | |
5100 | } | |
5101 | } | |
5102 | ||
f4d7e40a | 5103 | static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, |
de8f3a83 | 5104 | struct bpf_reg_state *dst_reg, |
f8ddadc4 | 5105 | enum bpf_reg_type type, |
fb2a311a | 5106 | bool range_right_open) |
969bf05e | 5107 | { |
fb2a311a | 5108 | u16 new_range; |
c6a9efa1 | 5109 | int i; |
2d2be8ca | 5110 | |
fb2a311a DB |
5111 | if (dst_reg->off < 0 || |
5112 | (dst_reg->off == 0 && range_right_open)) | |
f1174f77 EC |
5113 | /* This doesn't give us any range */ |
5114 | return; | |
5115 | ||
b03c9f9f EC |
5116 | if (dst_reg->umax_value > MAX_PACKET_OFF || |
5117 | dst_reg->umax_value + dst_reg->off > MAX_PACKET_OFF) | |
f1174f77 EC |
5118 | /* Risk of overflow. For instance, ptr + (1<<63) may be less |
5119 | * than pkt_end, but that's because it's also less than pkt. | |
5120 | */ | |
5121 | return; | |
5122 | ||
fb2a311a DB |
5123 | new_range = dst_reg->off; |
5124 | if (range_right_open) | |
5125 | new_range--; | |
5126 | ||
5127 | /* Examples for register markings: | |
2d2be8ca | 5128 | * |
fb2a311a | 5129 | * pkt_data in dst register: |
2d2be8ca DB |
5130 | * |
5131 | * r2 = r3; | |
5132 | * r2 += 8; | |
5133 | * if (r2 > pkt_end) goto <handle exception> | |
5134 | * <access okay> | |
5135 | * | |
b4e432f1 DB |
5136 | * r2 = r3; |
5137 | * r2 += 8; | |
5138 | * if (r2 < pkt_end) goto <access okay> | |
5139 | * <handle exception> | |
5140 | * | |
2d2be8ca DB |
5141 | * Where: |
5142 | * r2 == dst_reg, pkt_end == src_reg | |
5143 | * r2=pkt(id=n,off=8,r=0) | |
5144 | * r3=pkt(id=n,off=0,r=0) | |
5145 | * | |
fb2a311a | 5146 | * pkt_data in src register: |
2d2be8ca DB |
5147 | * |
5148 | * r2 = r3; | |
5149 | * r2 += 8; | |
5150 | * if (pkt_end >= r2) goto <access okay> | |
5151 | * <handle exception> | |
5152 | * | |
b4e432f1 DB |
5153 | * r2 = r3; |
5154 | * r2 += 8; | |
5155 | * if (pkt_end <= r2) goto <handle exception> | |
5156 | * <access okay> | |
5157 | * | |
2d2be8ca DB |
5158 | * Where: |
5159 | * pkt_end == dst_reg, r2 == src_reg | |
5160 | * r2=pkt(id=n,off=8,r=0) | |
5161 | * r3=pkt(id=n,off=0,r=0) | |
5162 | * | |
5163 | * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8) | |
fb2a311a DB |
5164 | * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8) |
5165 | * and [r3, r3 + 8-1) respectively is safe to access depending on | |
5166 | * the check. | |
969bf05e | 5167 | */ |
2d2be8ca | 5168 | |
f1174f77 EC |
5169 | /* If our ids match, then we must have the same max_value. And we |
5170 | * don't care about the other reg's fixed offset, since if it's too big | |
5171 | * the range won't allow anything. | |
5172 | * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16. | |
5173 | */ | |
c6a9efa1 PC |
5174 | for (i = 0; i <= vstate->curframe; i++) |
5175 | __find_good_pkt_pointers(vstate->frame[i], dst_reg, type, | |
5176 | new_range); | |
969bf05e AS |
5177 | } |
5178 | ||
4f7b3e82 AS |
5179 | /* compute branch direction of the expression "if (reg opcode val) goto target;" |
5180 | * and return: | |
5181 | * 1 - branch will be taken and "goto target" will be executed | |
5182 | * 0 - branch will not be taken and fall-through to next insn | |
5183 | * -1 - unknown. Example: "if (reg < 5)" is unknown when register value range [0,10] | |
5184 | */ | |
092ed096 JW |
5185 | static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode, |
5186 | bool is_jmp32) | |
4f7b3e82 | 5187 | { |
092ed096 | 5188 | struct bpf_reg_state reg_lo; |
a72dafaf JW |
5189 | s64 sval; |
5190 | ||
4f7b3e82 AS |
5191 | if (__is_pointer_value(false, reg)) |
5192 | return -1; | |
5193 | ||
092ed096 JW |
5194 | if (is_jmp32) { |
5195 | reg_lo = *reg; | |
5196 | reg = ®_lo; | |
5197 | /* For JMP32, only low 32 bits are compared, coerce_reg_to_size | |
5198 | * could truncate high bits and update umin/umax according to | |
5199 | * information of low bits. | |
5200 | */ | |
5201 | coerce_reg_to_size(reg, 4); | |
5202 | /* smin/smax need special handling. For example, after coerce, | |
5203 | * if smin_value is 0x00000000ffffffffLL, the value is -1 when | |
5204 | * used as operand to JMP32. It is a negative number from s32's | |
5205 | * point of view, while it is a positive number when seen as | |
5206 | * s64. The smin/smax are kept as s64, therefore, when used with | |
5207 | * JMP32, they need to be transformed into s32, then sign | |
5208 | * extended back to s64. | |
5209 | * | |
5210 | * Also, smin/smax were copied from umin/umax. If umin/umax has | |
5211 | * different sign bit, then min/max relationship doesn't | |
5212 | * maintain after casting into s32, for this case, set smin/smax | |
5213 | * to safest range. | |
5214 | */ | |
5215 | if ((reg->umax_value ^ reg->umin_value) & | |
5216 | (1ULL << 31)) { | |
5217 | reg->smin_value = S32_MIN; | |
5218 | reg->smax_value = S32_MAX; | |
5219 | } | |
5220 | reg->smin_value = (s64)(s32)reg->smin_value; | |
5221 | reg->smax_value = (s64)(s32)reg->smax_value; | |
5222 | ||
5223 | val = (u32)val; | |
5224 | sval = (s64)(s32)val; | |
5225 | } else { | |
5226 | sval = (s64)val; | |
5227 | } | |
a72dafaf | 5228 | |
4f7b3e82 AS |
5229 | switch (opcode) { |
5230 | case BPF_JEQ: | |
5231 | if (tnum_is_const(reg->var_off)) | |
5232 | return !!tnum_equals_const(reg->var_off, val); | |
5233 | break; | |
5234 | case BPF_JNE: | |
5235 | if (tnum_is_const(reg->var_off)) | |
5236 | return !tnum_equals_const(reg->var_off, val); | |
5237 | break; | |
960ea056 JK |
5238 | case BPF_JSET: |
5239 | if ((~reg->var_off.mask & reg->var_off.value) & val) | |
5240 | return 1; | |
5241 | if (!((reg->var_off.mask | reg->var_off.value) & val)) | |
5242 | return 0; | |
5243 | break; | |
4f7b3e82 AS |
5244 | case BPF_JGT: |
5245 | if (reg->umin_value > val) | |
5246 | return 1; | |
5247 | else if (reg->umax_value <= val) | |
5248 | return 0; | |
5249 | break; | |
5250 | case BPF_JSGT: | |
a72dafaf | 5251 | if (reg->smin_value > sval) |
4f7b3e82 | 5252 | return 1; |
a72dafaf | 5253 | else if (reg->smax_value < sval) |
4f7b3e82 AS |
5254 | return 0; |
5255 | break; | |
5256 | case BPF_JLT: | |
5257 | if (reg->umax_value < val) | |
5258 | return 1; | |
5259 | else if (reg->umin_value >= val) | |
5260 | return 0; | |
5261 | break; | |
5262 | case BPF_JSLT: | |
a72dafaf | 5263 | if (reg->smax_value < sval) |
4f7b3e82 | 5264 | return 1; |
a72dafaf | 5265 | else if (reg->smin_value >= sval) |
4f7b3e82 AS |
5266 | return 0; |
5267 | break; | |
5268 | case BPF_JGE: | |
5269 | if (reg->umin_value >= val) | |
5270 | return 1; | |
5271 | else if (reg->umax_value < val) | |
5272 | return 0; | |
5273 | break; | |
5274 | case BPF_JSGE: | |
a72dafaf | 5275 | if (reg->smin_value >= sval) |
4f7b3e82 | 5276 | return 1; |
a72dafaf | 5277 | else if (reg->smax_value < sval) |
4f7b3e82 AS |
5278 | return 0; |
5279 | break; | |
5280 | case BPF_JLE: | |
5281 | if (reg->umax_value <= val) | |
5282 | return 1; | |
5283 | else if (reg->umin_value > val) | |
5284 | return 0; | |
5285 | break; | |
5286 | case BPF_JSLE: | |
a72dafaf | 5287 | if (reg->smax_value <= sval) |
4f7b3e82 | 5288 | return 1; |
a72dafaf | 5289 | else if (reg->smin_value > sval) |
4f7b3e82 AS |
5290 | return 0; |
5291 | break; | |
5292 | } | |
5293 | ||
5294 | return -1; | |
5295 | } | |
5296 | ||
092ed096 JW |
5297 | /* Generate min value of the high 32-bit from TNUM info. */ |
5298 | static u64 gen_hi_min(struct tnum var) | |
5299 | { | |
5300 | return var.value & ~0xffffffffULL; | |
5301 | } | |
5302 | ||
5303 | /* Generate max value of the high 32-bit from TNUM info. */ | |
5304 | static u64 gen_hi_max(struct tnum var) | |
5305 | { | |
5306 | return (var.value | var.mask) & ~0xffffffffULL; | |
5307 | } | |
5308 | ||
5309 | /* Return true if VAL is compared with a s64 sign extended from s32, and they | |
5310 | * are with the same signedness. | |
5311 | */ | |
5312 | static bool cmp_val_with_extended_s64(s64 sval, struct bpf_reg_state *reg) | |
5313 | { | |
5314 | return ((s32)sval >= 0 && | |
5315 | reg->smin_value >= 0 && reg->smax_value <= S32_MAX) || | |
5316 | ((s32)sval < 0 && | |
5317 | reg->smax_value <= 0 && reg->smin_value >= S32_MIN); | |
5318 | } | |
5319 | ||
48461135 JB |
5320 | /* Adjusts the register min/max values in the case that the dst_reg is the |
5321 | * variable register that we are working on, and src_reg is a constant or we're | |
5322 | * simply doing a BPF_K check. | |
f1174f77 | 5323 | * In JEQ/JNE cases we also adjust the var_off values. |
48461135 JB |
5324 | */ |
5325 | static void reg_set_min_max(struct bpf_reg_state *true_reg, | |
5326 | struct bpf_reg_state *false_reg, u64 val, | |
092ed096 | 5327 | u8 opcode, bool is_jmp32) |
48461135 | 5328 | { |
a72dafaf JW |
5329 | s64 sval; |
5330 | ||
f1174f77 EC |
5331 | /* If the dst_reg is a pointer, we can't learn anything about its |
5332 | * variable offset from the compare (unless src_reg were a pointer into | |
5333 | * the same object, but we don't bother with that. | |
5334 | * Since false_reg and true_reg have the same type by construction, we | |
5335 | * only need to check one of them for pointerness. | |
5336 | */ | |
5337 | if (__is_pointer_value(false, false_reg)) | |
5338 | return; | |
4cabc5b1 | 5339 | |
092ed096 JW |
5340 | val = is_jmp32 ? (u32)val : val; |
5341 | sval = is_jmp32 ? (s64)(s32)val : (s64)val; | |
a72dafaf | 5342 | |
48461135 JB |
5343 | switch (opcode) { |
5344 | case BPF_JEQ: | |
48461135 | 5345 | case BPF_JNE: |
a72dafaf JW |
5346 | { |
5347 | struct bpf_reg_state *reg = | |
5348 | opcode == BPF_JEQ ? true_reg : false_reg; | |
5349 | ||
5350 | /* For BPF_JEQ, if this is false we know nothing Jon Snow, but | |
5351 | * if it is true we know the value for sure. Likewise for | |
5352 | * BPF_JNE. | |
48461135 | 5353 | */ |
092ed096 JW |
5354 | if (is_jmp32) { |
5355 | u64 old_v = reg->var_off.value; | |
5356 | u64 hi_mask = ~0xffffffffULL; | |
5357 | ||
5358 | reg->var_off.value = (old_v & hi_mask) | val; | |
5359 | reg->var_off.mask &= hi_mask; | |
5360 | } else { | |
5361 | __mark_reg_known(reg, val); | |
5362 | } | |
48461135 | 5363 | break; |
a72dafaf | 5364 | } |
960ea056 JK |
5365 | case BPF_JSET: |
5366 | false_reg->var_off = tnum_and(false_reg->var_off, | |
5367 | tnum_const(~val)); | |
5368 | if (is_power_of_2(val)) | |
5369 | true_reg->var_off = tnum_or(true_reg->var_off, | |
5370 | tnum_const(val)); | |
5371 | break; | |
48461135 | 5372 | case BPF_JGE: |
a72dafaf JW |
5373 | case BPF_JGT: |
5374 | { | |
5375 | u64 false_umax = opcode == BPF_JGT ? val : val - 1; | |
5376 | u64 true_umin = opcode == BPF_JGT ? val + 1 : val; | |
5377 | ||
092ed096 JW |
5378 | if (is_jmp32) { |
5379 | false_umax += gen_hi_max(false_reg->var_off); | |
5380 | true_umin += gen_hi_min(true_reg->var_off); | |
5381 | } | |
a72dafaf JW |
5382 | false_reg->umax_value = min(false_reg->umax_value, false_umax); |
5383 | true_reg->umin_value = max(true_reg->umin_value, true_umin); | |
b03c9f9f | 5384 | break; |
a72dafaf | 5385 | } |
48461135 | 5386 | case BPF_JSGE: |
a72dafaf JW |
5387 | case BPF_JSGT: |
5388 | { | |
5389 | s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1; | |
5390 | s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval; | |
5391 | ||
092ed096 JW |
5392 | /* If the full s64 was not sign-extended from s32 then don't |
5393 | * deduct further info. | |
5394 | */ | |
5395 | if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) | |
5396 | break; | |
a72dafaf JW |
5397 | false_reg->smax_value = min(false_reg->smax_value, false_smax); |
5398 | true_reg->smin_value = max(true_reg->smin_value, true_smin); | |
48461135 | 5399 | break; |
a72dafaf | 5400 | } |
b4e432f1 | 5401 | case BPF_JLE: |
a72dafaf JW |
5402 | case BPF_JLT: |
5403 | { | |
5404 | u64 false_umin = opcode == BPF_JLT ? val : val + 1; | |
5405 | u64 true_umax = opcode == BPF_JLT ? val - 1 : val; | |
5406 | ||
092ed096 JW |
5407 | if (is_jmp32) { |
5408 | false_umin += gen_hi_min(false_reg->var_off); | |
5409 | true_umax += gen_hi_max(true_reg->var_off); | |
5410 | } | |
a72dafaf JW |
5411 | false_reg->umin_value = max(false_reg->umin_value, false_umin); |
5412 | true_reg->umax_value = min(true_reg->umax_value, true_umax); | |
b4e432f1 | 5413 | break; |
a72dafaf | 5414 | } |
b4e432f1 | 5415 | case BPF_JSLE: |
a72dafaf JW |
5416 | case BPF_JSLT: |
5417 | { | |
5418 | s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1; | |
5419 | s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval; | |
5420 | ||
092ed096 JW |
5421 | if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) |
5422 | break; | |
a72dafaf JW |
5423 | false_reg->smin_value = max(false_reg->smin_value, false_smin); |
5424 | true_reg->smax_value = min(true_reg->smax_value, true_smax); | |
b4e432f1 | 5425 | break; |
a72dafaf | 5426 | } |
48461135 JB |
5427 | default: |
5428 | break; | |
5429 | } | |
5430 | ||
b03c9f9f EC |
5431 | __reg_deduce_bounds(false_reg); |
5432 | __reg_deduce_bounds(true_reg); | |
5433 | /* We might have learned some bits from the bounds. */ | |
5434 | __reg_bound_offset(false_reg); | |
5435 | __reg_bound_offset(true_reg); | |
5436 | /* Intersecting with the old var_off might have improved our bounds | |
5437 | * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), | |
5438 | * then new var_off is (0; 0x7f...fc) which improves our umax. | |
5439 | */ | |
5440 | __update_reg_bounds(false_reg); | |
5441 | __update_reg_bounds(true_reg); | |
48461135 JB |
5442 | } |
5443 | ||
f1174f77 EC |
5444 | /* Same as above, but for the case that dst_reg holds a constant and src_reg is |
5445 | * the variable reg. | |
48461135 JB |
5446 | */ |
5447 | static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, | |
5448 | struct bpf_reg_state *false_reg, u64 val, | |
092ed096 | 5449 | u8 opcode, bool is_jmp32) |
48461135 | 5450 | { |
a72dafaf JW |
5451 | s64 sval; |
5452 | ||
f1174f77 EC |
5453 | if (__is_pointer_value(false, false_reg)) |
5454 | return; | |
4cabc5b1 | 5455 | |
092ed096 JW |
5456 | val = is_jmp32 ? (u32)val : val; |
5457 | sval = is_jmp32 ? (s64)(s32)val : (s64)val; | |
a72dafaf | 5458 | |
48461135 JB |
5459 | switch (opcode) { |
5460 | case BPF_JEQ: | |
48461135 | 5461 | case BPF_JNE: |
a72dafaf JW |
5462 | { |
5463 | struct bpf_reg_state *reg = | |
5464 | opcode == BPF_JEQ ? true_reg : false_reg; | |
5465 | ||
092ed096 JW |
5466 | if (is_jmp32) { |
5467 | u64 old_v = reg->var_off.value; | |
5468 | u64 hi_mask = ~0xffffffffULL; | |
5469 | ||
5470 | reg->var_off.value = (old_v & hi_mask) | val; | |
5471 | reg->var_off.mask &= hi_mask; | |
5472 | } else { | |
5473 | __mark_reg_known(reg, val); | |
5474 | } | |
48461135 | 5475 | break; |
a72dafaf | 5476 | } |
960ea056 JK |
5477 | case BPF_JSET: |
5478 | false_reg->var_off = tnum_and(false_reg->var_off, | |
5479 | tnum_const(~val)); | |
5480 | if (is_power_of_2(val)) | |
5481 | true_reg->var_off = tnum_or(true_reg->var_off, | |
5482 | tnum_const(val)); | |
5483 | break; | |
48461135 | 5484 | case BPF_JGE: |
a72dafaf JW |
5485 | case BPF_JGT: |
5486 | { | |
5487 | u64 false_umin = opcode == BPF_JGT ? val : val + 1; | |
5488 | u64 true_umax = opcode == BPF_JGT ? val - 1 : val; | |
5489 | ||
092ed096 JW |
5490 | if (is_jmp32) { |
5491 | false_umin += gen_hi_min(false_reg->var_off); | |
5492 | true_umax += gen_hi_max(true_reg->var_off); | |
5493 | } | |
a72dafaf JW |
5494 | false_reg->umin_value = max(false_reg->umin_value, false_umin); |
5495 | true_reg->umax_value = min(true_reg->umax_value, true_umax); | |
b03c9f9f | 5496 | break; |
a72dafaf | 5497 | } |
48461135 | 5498 | case BPF_JSGE: |
a72dafaf JW |
5499 | case BPF_JSGT: |
5500 | { | |
5501 | s64 false_smin = opcode == BPF_JSGT ? sval : sval + 1; | |
5502 | s64 true_smax = opcode == BPF_JSGT ? sval - 1 : sval; | |
5503 | ||
092ed096 JW |
5504 | if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) |
5505 | break; | |
a72dafaf JW |
5506 | false_reg->smin_value = max(false_reg->smin_value, false_smin); |
5507 | true_reg->smax_value = min(true_reg->smax_value, true_smax); | |
48461135 | 5508 | break; |
a72dafaf | 5509 | } |
b4e432f1 | 5510 | case BPF_JLE: |
a72dafaf JW |
5511 | case BPF_JLT: |
5512 | { | |
5513 | u64 false_umax = opcode == BPF_JLT ? val : val - 1; | |
5514 | u64 true_umin = opcode == BPF_JLT ? val + 1 : val; | |
5515 | ||
092ed096 JW |
5516 | if (is_jmp32) { |
5517 | false_umax += gen_hi_max(false_reg->var_off); | |
5518 | true_umin += gen_hi_min(true_reg->var_off); | |
5519 | } | |
a72dafaf JW |
5520 | false_reg->umax_value = min(false_reg->umax_value, false_umax); |
5521 | true_reg->umin_value = max(true_reg->umin_value, true_umin); | |
b4e432f1 | 5522 | break; |
a72dafaf | 5523 | } |
b4e432f1 | 5524 | case BPF_JSLE: |
a72dafaf JW |
5525 | case BPF_JSLT: |
5526 | { | |
5527 | s64 false_smax = opcode == BPF_JSLT ? sval : sval - 1; | |
5528 | s64 true_smin = opcode == BPF_JSLT ? sval + 1 : sval; | |
5529 | ||
092ed096 JW |
5530 | if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg)) |
5531 | break; | |
a72dafaf JW |
5532 | false_reg->smax_value = min(false_reg->smax_value, false_smax); |
5533 | true_reg->smin_value = max(true_reg->smin_value, true_smin); | |
b4e432f1 | 5534 | break; |
a72dafaf | 5535 | } |
48461135 JB |
5536 | default: |
5537 | break; | |
5538 | } | |
5539 | ||
b03c9f9f EC |
5540 | __reg_deduce_bounds(false_reg); |
5541 | __reg_deduce_bounds(true_reg); | |
5542 | /* We might have learned some bits from the bounds. */ | |
5543 | __reg_bound_offset(false_reg); | |
5544 | __reg_bound_offset(true_reg); | |
5545 | /* Intersecting with the old var_off might have improved our bounds | |
5546 | * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), | |
5547 | * then new var_off is (0; 0x7f...fc) which improves our umax. | |
5548 | */ | |
5549 | __update_reg_bounds(false_reg); | |
5550 | __update_reg_bounds(true_reg); | |
f1174f77 EC |
5551 | } |
5552 | ||
5553 | /* Regs are known to be equal, so intersect their min/max/var_off */ | |
5554 | static void __reg_combine_min_max(struct bpf_reg_state *src_reg, | |
5555 | struct bpf_reg_state *dst_reg) | |
5556 | { | |
b03c9f9f EC |
5557 | src_reg->umin_value = dst_reg->umin_value = max(src_reg->umin_value, |
5558 | dst_reg->umin_value); | |
5559 | src_reg->umax_value = dst_reg->umax_value = min(src_reg->umax_value, | |
5560 | dst_reg->umax_value); | |
5561 | src_reg->smin_value = dst_reg->smin_value = max(src_reg->smin_value, | |
5562 | dst_reg->smin_value); | |
5563 | src_reg->smax_value = dst_reg->smax_value = min(src_reg->smax_value, | |
5564 | dst_reg->smax_value); | |
f1174f77 EC |
5565 | src_reg->var_off = dst_reg->var_off = tnum_intersect(src_reg->var_off, |
5566 | dst_reg->var_off); | |
b03c9f9f EC |
5567 | /* We might have learned new bounds from the var_off. */ |
5568 | __update_reg_bounds(src_reg); | |
5569 | __update_reg_bounds(dst_reg); | |
5570 | /* We might have learned something about the sign bit. */ | |
5571 | __reg_deduce_bounds(src_reg); | |
5572 | __reg_deduce_bounds(dst_reg); | |
5573 | /* We might have learned some bits from the bounds. */ | |
5574 | __reg_bound_offset(src_reg); | |
5575 | __reg_bound_offset(dst_reg); | |
5576 | /* Intersecting with the old var_off might have improved our bounds | |
5577 | * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), | |
5578 | * then new var_off is (0; 0x7f...fc) which improves our umax. | |
5579 | */ | |
5580 | __update_reg_bounds(src_reg); | |
5581 | __update_reg_bounds(dst_reg); | |
f1174f77 EC |
5582 | } |
5583 | ||
5584 | static void reg_combine_min_max(struct bpf_reg_state *true_src, | |
5585 | struct bpf_reg_state *true_dst, | |
5586 | struct bpf_reg_state *false_src, | |
5587 | struct bpf_reg_state *false_dst, | |
5588 | u8 opcode) | |
5589 | { | |
5590 | switch (opcode) { | |
5591 | case BPF_JEQ: | |
5592 | __reg_combine_min_max(true_src, true_dst); | |
5593 | break; | |
5594 | case BPF_JNE: | |
5595 | __reg_combine_min_max(false_src, false_dst); | |
b03c9f9f | 5596 | break; |
4cabc5b1 | 5597 | } |
48461135 JB |
5598 | } |
5599 | ||
fd978bf7 JS |
5600 | static void mark_ptr_or_null_reg(struct bpf_func_state *state, |
5601 | struct bpf_reg_state *reg, u32 id, | |
840b9615 | 5602 | bool is_null) |
57a09bf0 | 5603 | { |
840b9615 | 5604 | if (reg_type_may_be_null(reg->type) && reg->id == id) { |
f1174f77 EC |
5605 | /* Old offset (both fixed and variable parts) should |
5606 | * have been known-zero, because we don't allow pointer | |
5607 | * arithmetic on pointers that might be NULL. | |
5608 | */ | |
b03c9f9f EC |
5609 | if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || |
5610 | !tnum_equals_const(reg->var_off, 0) || | |
f1174f77 | 5611 | reg->off)) { |
b03c9f9f EC |
5612 | __mark_reg_known_zero(reg); |
5613 | reg->off = 0; | |
f1174f77 EC |
5614 | } |
5615 | if (is_null) { | |
5616 | reg->type = SCALAR_VALUE; | |
840b9615 JS |
5617 | } else if (reg->type == PTR_TO_MAP_VALUE_OR_NULL) { |
5618 | if (reg->map_ptr->inner_map_meta) { | |
5619 | reg->type = CONST_PTR_TO_MAP; | |
5620 | reg->map_ptr = reg->map_ptr->inner_map_meta; | |
fada7fdc JL |
5621 | } else if (reg->map_ptr->map_type == |
5622 | BPF_MAP_TYPE_XSKMAP) { | |
5623 | reg->type = PTR_TO_XDP_SOCK; | |
840b9615 JS |
5624 | } else { |
5625 | reg->type = PTR_TO_MAP_VALUE; | |
5626 | } | |
c64b7983 JS |
5627 | } else if (reg->type == PTR_TO_SOCKET_OR_NULL) { |
5628 | reg->type = PTR_TO_SOCKET; | |
46f8bc92 MKL |
5629 | } else if (reg->type == PTR_TO_SOCK_COMMON_OR_NULL) { |
5630 | reg->type = PTR_TO_SOCK_COMMON; | |
655a51e5 MKL |
5631 | } else if (reg->type == PTR_TO_TCP_SOCK_OR_NULL) { |
5632 | reg->type = PTR_TO_TCP_SOCK; | |
56f668df | 5633 | } |
1b986589 MKL |
5634 | if (is_null) { |
5635 | /* We don't need id and ref_obj_id from this point | |
5636 | * onwards anymore, thus we should better reset it, | |
5637 | * so that state pruning has chances to take effect. | |
5638 | */ | |
5639 | reg->id = 0; | |
5640 | reg->ref_obj_id = 0; | |
5641 | } else if (!reg_may_point_to_spin_lock(reg)) { | |
5642 | /* For not-NULL ptr, reg->ref_obj_id will be reset | |
5643 | * in release_reg_references(). | |
5644 | * | |
5645 | * reg->id is still used by spin_lock ptr. Other | |
5646 | * than spin_lock ptr type, reg->id can be reset. | |
fd978bf7 JS |
5647 | */ |
5648 | reg->id = 0; | |
56f668df | 5649 | } |
57a09bf0 TG |
5650 | } |
5651 | } | |
5652 | ||
c6a9efa1 PC |
5653 | static void __mark_ptr_or_null_regs(struct bpf_func_state *state, u32 id, |
5654 | bool is_null) | |
5655 | { | |
5656 | struct bpf_reg_state *reg; | |
5657 | int i; | |
5658 | ||
5659 | for (i = 0; i < MAX_BPF_REG; i++) | |
5660 | mark_ptr_or_null_reg(state, &state->regs[i], id, is_null); | |
5661 | ||
5662 | bpf_for_each_spilled_reg(i, state, reg) { | |
5663 | if (!reg) | |
5664 | continue; | |
5665 | mark_ptr_or_null_reg(state, reg, id, is_null); | |
5666 | } | |
5667 | } | |
5668 | ||
57a09bf0 TG |
5669 | /* The logic is similar to find_good_pkt_pointers(), both could eventually |
5670 | * be folded together at some point. | |
5671 | */ | |
840b9615 JS |
5672 | static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno, |
5673 | bool is_null) | |
57a09bf0 | 5674 | { |
f4d7e40a | 5675 | struct bpf_func_state *state = vstate->frame[vstate->curframe]; |
c6a9efa1 | 5676 | struct bpf_reg_state *regs = state->regs; |
1b986589 | 5677 | u32 ref_obj_id = regs[regno].ref_obj_id; |
a08dd0da | 5678 | u32 id = regs[regno].id; |
c6a9efa1 | 5679 | int i; |
57a09bf0 | 5680 | |
1b986589 MKL |
5681 | if (ref_obj_id && ref_obj_id == id && is_null) |
5682 | /* regs[regno] is in the " == NULL" branch. | |
5683 | * No one could have freed the reference state before | |
5684 | * doing the NULL check. | |
5685 | */ | |
5686 | WARN_ON_ONCE(release_reference_state(state, id)); | |
fd978bf7 | 5687 | |
c6a9efa1 PC |
5688 | for (i = 0; i <= vstate->curframe; i++) |
5689 | __mark_ptr_or_null_regs(vstate->frame[i], id, is_null); | |
57a09bf0 TG |
5690 | } |
5691 | ||
5beca081 DB |
5692 | static bool try_match_pkt_pointers(const struct bpf_insn *insn, |
5693 | struct bpf_reg_state *dst_reg, | |
5694 | struct bpf_reg_state *src_reg, | |
5695 | struct bpf_verifier_state *this_branch, | |
5696 | struct bpf_verifier_state *other_branch) | |
5697 | { | |
5698 | if (BPF_SRC(insn->code) != BPF_X) | |
5699 | return false; | |
5700 | ||
092ed096 JW |
5701 | /* Pointers are always 64-bit. */ |
5702 | if (BPF_CLASS(insn->code) == BPF_JMP32) | |
5703 | return false; | |
5704 | ||
5beca081 DB |
5705 | switch (BPF_OP(insn->code)) { |
5706 | case BPF_JGT: | |
5707 | if ((dst_reg->type == PTR_TO_PACKET && | |
5708 | src_reg->type == PTR_TO_PACKET_END) || | |
5709 | (dst_reg->type == PTR_TO_PACKET_META && | |
5710 | reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) { | |
5711 | /* pkt_data' > pkt_end, pkt_meta' > pkt_data */ | |
5712 | find_good_pkt_pointers(this_branch, dst_reg, | |
5713 | dst_reg->type, false); | |
5714 | } else if ((dst_reg->type == PTR_TO_PACKET_END && | |
5715 | src_reg->type == PTR_TO_PACKET) || | |
5716 | (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && | |
5717 | src_reg->type == PTR_TO_PACKET_META)) { | |
5718 | /* pkt_end > pkt_data', pkt_data > pkt_meta' */ | |
5719 | find_good_pkt_pointers(other_branch, src_reg, | |
5720 | src_reg->type, true); | |
5721 | } else { | |
5722 | return false; | |
5723 | } | |
5724 | break; | |
5725 | case BPF_JLT: | |
5726 | if ((dst_reg->type == PTR_TO_PACKET && | |
5727 | src_reg->type == PTR_TO_PACKET_END) || | |
5728 | (dst_reg->type == PTR_TO_PACKET_META && | |
5729 | reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) { | |
5730 | /* pkt_data' < pkt_end, pkt_meta' < pkt_data */ | |
5731 | find_good_pkt_pointers(other_branch, dst_reg, | |
5732 | dst_reg->type, true); | |
5733 | } else if ((dst_reg->type == PTR_TO_PACKET_END && | |
5734 | src_reg->type == PTR_TO_PACKET) || | |
5735 | (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && | |
5736 | src_reg->type == PTR_TO_PACKET_META)) { | |
5737 | /* pkt_end < pkt_data', pkt_data > pkt_meta' */ | |
5738 | find_good_pkt_pointers(this_branch, src_reg, | |
5739 | src_reg->type, false); | |
5740 | } else { | |
5741 | return false; | |
5742 | } | |
5743 | break; | |
5744 | case BPF_JGE: | |
5745 | if ((dst_reg->type == PTR_TO_PACKET && | |
5746 | src_reg->type == PTR_TO_PACKET_END) || | |
5747 | (dst_reg->type == PTR_TO_PACKET_META && | |
5748 | reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) { | |
5749 | /* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */ | |
5750 | find_good_pkt_pointers(this_branch, dst_reg, | |
5751 | dst_reg->type, true); | |
5752 | } else if ((dst_reg->type == PTR_TO_PACKET_END && | |
5753 | src_reg->type == PTR_TO_PACKET) || | |
5754 | (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && | |
5755 | src_reg->type == PTR_TO_PACKET_META)) { | |
5756 | /* pkt_end >= pkt_data', pkt_data >= pkt_meta' */ | |
5757 | find_good_pkt_pointers(other_branch, src_reg, | |
5758 | src_reg->type, false); | |
5759 | } else { | |
5760 | return false; | |
5761 | } | |
5762 | break; | |
5763 | case BPF_JLE: | |
5764 | if ((dst_reg->type == PTR_TO_PACKET && | |
5765 | src_reg->type == PTR_TO_PACKET_END) || | |
5766 | (dst_reg->type == PTR_TO_PACKET_META && | |
5767 | reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) { | |
5768 | /* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */ | |
5769 | find_good_pkt_pointers(other_branch, dst_reg, | |
5770 | dst_reg->type, false); | |
5771 | } else if ((dst_reg->type == PTR_TO_PACKET_END && | |
5772 | src_reg->type == PTR_TO_PACKET) || | |
5773 | (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) && | |
5774 | src_reg->type == PTR_TO_PACKET_META)) { | |
5775 | /* pkt_end <= pkt_data', pkt_data <= pkt_meta' */ | |
5776 | find_good_pkt_pointers(this_branch, src_reg, | |
5777 | src_reg->type, true); | |
5778 | } else { | |
5779 | return false; | |
5780 | } | |
5781 | break; | |
5782 | default: | |
5783 | return false; | |
5784 | } | |
5785 | ||
5786 | return true; | |
5787 | } | |
5788 | ||
58e2af8b | 5789 | static int check_cond_jmp_op(struct bpf_verifier_env *env, |
17a52670 AS |
5790 | struct bpf_insn *insn, int *insn_idx) |
5791 | { | |
f4d7e40a AS |
5792 | struct bpf_verifier_state *this_branch = env->cur_state; |
5793 | struct bpf_verifier_state *other_branch; | |
5794 | struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs; | |
fb8d251e | 5795 | struct bpf_reg_state *dst_reg, *other_branch_regs, *src_reg = NULL; |
17a52670 | 5796 | u8 opcode = BPF_OP(insn->code); |
092ed096 | 5797 | bool is_jmp32; |
fb8d251e | 5798 | int pred = -1; |
17a52670 AS |
5799 | int err; |
5800 | ||
092ed096 JW |
5801 | /* Only conditional jumps are expected to reach here. */ |
5802 | if (opcode == BPF_JA || opcode > BPF_JSLE) { | |
5803 | verbose(env, "invalid BPF_JMP/JMP32 opcode %x\n", opcode); | |
17a52670 AS |
5804 | return -EINVAL; |
5805 | } | |
5806 | ||
5807 | if (BPF_SRC(insn->code) == BPF_X) { | |
5808 | if (insn->imm != 0) { | |
092ed096 | 5809 | verbose(env, "BPF_JMP/JMP32 uses reserved fields\n"); |
17a52670 AS |
5810 | return -EINVAL; |
5811 | } | |
5812 | ||
5813 | /* check src1 operand */ | |
dc503a8a | 5814 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
5815 | if (err) |
5816 | return err; | |
1be7f75d AS |
5817 | |
5818 | if (is_pointer_value(env, insn->src_reg)) { | |
61bd5218 | 5819 | verbose(env, "R%d pointer comparison prohibited\n", |
1be7f75d AS |
5820 | insn->src_reg); |
5821 | return -EACCES; | |
5822 | } | |
fb8d251e | 5823 | src_reg = ®s[insn->src_reg]; |
17a52670 AS |
5824 | } else { |
5825 | if (insn->src_reg != BPF_REG_0) { | |
092ed096 | 5826 | verbose(env, "BPF_JMP/JMP32 uses reserved fields\n"); |
17a52670 AS |
5827 | return -EINVAL; |
5828 | } | |
5829 | } | |
5830 | ||
5831 | /* check src2 operand */ | |
dc503a8a | 5832 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
5833 | if (err) |
5834 | return err; | |
5835 | ||
1a0dc1ac | 5836 | dst_reg = ®s[insn->dst_reg]; |
092ed096 | 5837 | is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32; |
1a0dc1ac | 5838 | |
fb8d251e AS |
5839 | if (BPF_SRC(insn->code) == BPF_K) |
5840 | pred = is_branch_taken(dst_reg, insn->imm, | |
5841 | opcode, is_jmp32); | |
5842 | else if (src_reg->type == SCALAR_VALUE && | |
5843 | tnum_is_const(src_reg->var_off)) | |
5844 | pred = is_branch_taken(dst_reg, src_reg->var_off.value, | |
5845 | opcode, is_jmp32); | |
b5dc0163 AS |
5846 | if (pred >= 0) { |
5847 | err = mark_chain_precision(env, insn->dst_reg); | |
5848 | if (BPF_SRC(insn->code) == BPF_X && !err) | |
5849 | err = mark_chain_precision(env, insn->src_reg); | |
5850 | if (err) | |
5851 | return err; | |
5852 | } | |
fb8d251e AS |
5853 | if (pred == 1) { |
5854 | /* only follow the goto, ignore fall-through */ | |
5855 | *insn_idx += insn->off; | |
5856 | return 0; | |
5857 | } else if (pred == 0) { | |
5858 | /* only follow fall-through branch, since | |
5859 | * that's where the program will go | |
5860 | */ | |
5861 | return 0; | |
17a52670 AS |
5862 | } |
5863 | ||
979d63d5 DB |
5864 | other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx, |
5865 | false); | |
17a52670 AS |
5866 | if (!other_branch) |
5867 | return -EFAULT; | |
f4d7e40a | 5868 | other_branch_regs = other_branch->frame[other_branch->curframe]->regs; |
17a52670 | 5869 | |
48461135 JB |
5870 | /* detect if we are comparing against a constant value so we can adjust |
5871 | * our min/max values for our dst register. | |
f1174f77 EC |
5872 | * this is only legit if both are scalars (or pointers to the same |
5873 | * object, I suppose, but we don't support that right now), because | |
5874 | * otherwise the different base pointers mean the offsets aren't | |
5875 | * comparable. | |
48461135 JB |
5876 | */ |
5877 | if (BPF_SRC(insn->code) == BPF_X) { | |
092ed096 JW |
5878 | struct bpf_reg_state *src_reg = ®s[insn->src_reg]; |
5879 | struct bpf_reg_state lo_reg0 = *dst_reg; | |
5880 | struct bpf_reg_state lo_reg1 = *src_reg; | |
5881 | struct bpf_reg_state *src_lo, *dst_lo; | |
5882 | ||
5883 | dst_lo = &lo_reg0; | |
5884 | src_lo = &lo_reg1; | |
5885 | coerce_reg_to_size(dst_lo, 4); | |
5886 | coerce_reg_to_size(src_lo, 4); | |
5887 | ||
f1174f77 | 5888 | if (dst_reg->type == SCALAR_VALUE && |
092ed096 JW |
5889 | src_reg->type == SCALAR_VALUE) { |
5890 | if (tnum_is_const(src_reg->var_off) || | |
5891 | (is_jmp32 && tnum_is_const(src_lo->var_off))) | |
f4d7e40a | 5892 | reg_set_min_max(&other_branch_regs[insn->dst_reg], |
092ed096 JW |
5893 | dst_reg, |
5894 | is_jmp32 | |
5895 | ? src_lo->var_off.value | |
5896 | : src_reg->var_off.value, | |
5897 | opcode, is_jmp32); | |
5898 | else if (tnum_is_const(dst_reg->var_off) || | |
5899 | (is_jmp32 && tnum_is_const(dst_lo->var_off))) | |
f4d7e40a | 5900 | reg_set_min_max_inv(&other_branch_regs[insn->src_reg], |
092ed096 JW |
5901 | src_reg, |
5902 | is_jmp32 | |
5903 | ? dst_lo->var_off.value | |
5904 | : dst_reg->var_off.value, | |
5905 | opcode, is_jmp32); | |
5906 | else if (!is_jmp32 && | |
5907 | (opcode == BPF_JEQ || opcode == BPF_JNE)) | |
f1174f77 | 5908 | /* Comparing for equality, we can combine knowledge */ |
f4d7e40a AS |
5909 | reg_combine_min_max(&other_branch_regs[insn->src_reg], |
5910 | &other_branch_regs[insn->dst_reg], | |
092ed096 | 5911 | src_reg, dst_reg, opcode); |
f1174f77 EC |
5912 | } |
5913 | } else if (dst_reg->type == SCALAR_VALUE) { | |
f4d7e40a | 5914 | reg_set_min_max(&other_branch_regs[insn->dst_reg], |
092ed096 | 5915 | dst_reg, insn->imm, opcode, is_jmp32); |
48461135 JB |
5916 | } |
5917 | ||
092ed096 JW |
5918 | /* detect if R == 0 where R is returned from bpf_map_lookup_elem(). |
5919 | * NOTE: these optimizations below are related with pointer comparison | |
5920 | * which will never be JMP32. | |
5921 | */ | |
5922 | if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K && | |
1a0dc1ac | 5923 | insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) && |
840b9615 JS |
5924 | reg_type_may_be_null(dst_reg->type)) { |
5925 | /* Mark all identical registers in each branch as either | |
57a09bf0 TG |
5926 | * safe or unknown depending R == 0 or R != 0 conditional. |
5927 | */ | |
840b9615 JS |
5928 | mark_ptr_or_null_regs(this_branch, insn->dst_reg, |
5929 | opcode == BPF_JNE); | |
5930 | mark_ptr_or_null_regs(other_branch, insn->dst_reg, | |
5931 | opcode == BPF_JEQ); | |
5beca081 DB |
5932 | } else if (!try_match_pkt_pointers(insn, dst_reg, ®s[insn->src_reg], |
5933 | this_branch, other_branch) && | |
5934 | is_pointer_value(env, insn->dst_reg)) { | |
61bd5218 JK |
5935 | verbose(env, "R%d pointer comparison prohibited\n", |
5936 | insn->dst_reg); | |
1be7f75d | 5937 | return -EACCES; |
17a52670 | 5938 | } |
06ee7115 | 5939 | if (env->log.level & BPF_LOG_LEVEL) |
f4d7e40a | 5940 | print_verifier_state(env, this_branch->frame[this_branch->curframe]); |
17a52670 AS |
5941 | return 0; |
5942 | } | |
5943 | ||
17a52670 | 5944 | /* verify BPF_LD_IMM64 instruction */ |
58e2af8b | 5945 | static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) |
17a52670 | 5946 | { |
d8eca5bb | 5947 | struct bpf_insn_aux_data *aux = cur_aux(env); |
638f5b90 | 5948 | struct bpf_reg_state *regs = cur_regs(env); |
d8eca5bb | 5949 | struct bpf_map *map; |
17a52670 AS |
5950 | int err; |
5951 | ||
5952 | if (BPF_SIZE(insn->code) != BPF_DW) { | |
61bd5218 | 5953 | verbose(env, "invalid BPF_LD_IMM insn\n"); |
17a52670 AS |
5954 | return -EINVAL; |
5955 | } | |
5956 | if (insn->off != 0) { | |
61bd5218 | 5957 | verbose(env, "BPF_LD_IMM64 uses reserved fields\n"); |
17a52670 AS |
5958 | return -EINVAL; |
5959 | } | |
5960 | ||
dc503a8a | 5961 | err = check_reg_arg(env, insn->dst_reg, DST_OP); |
17a52670 AS |
5962 | if (err) |
5963 | return err; | |
5964 | ||
6b173873 | 5965 | if (insn->src_reg == 0) { |
6b173873 JK |
5966 | u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; |
5967 | ||
f1174f77 | 5968 | regs[insn->dst_reg].type = SCALAR_VALUE; |
b03c9f9f | 5969 | __mark_reg_known(®s[insn->dst_reg], imm); |
17a52670 | 5970 | return 0; |
6b173873 | 5971 | } |
17a52670 | 5972 | |
d8eca5bb DB |
5973 | map = env->used_maps[aux->map_index]; |
5974 | mark_reg_known_zero(env, regs, insn->dst_reg); | |
5975 | regs[insn->dst_reg].map_ptr = map; | |
5976 | ||
5977 | if (insn->src_reg == BPF_PSEUDO_MAP_VALUE) { | |
5978 | regs[insn->dst_reg].type = PTR_TO_MAP_VALUE; | |
5979 | regs[insn->dst_reg].off = aux->map_off; | |
5980 | if (map_value_has_spin_lock(map)) | |
5981 | regs[insn->dst_reg].id = ++env->id_gen; | |
5982 | } else if (insn->src_reg == BPF_PSEUDO_MAP_FD) { | |
5983 | regs[insn->dst_reg].type = CONST_PTR_TO_MAP; | |
5984 | } else { | |
5985 | verbose(env, "bpf verifier is misconfigured\n"); | |
5986 | return -EINVAL; | |
5987 | } | |
17a52670 | 5988 | |
17a52670 AS |
5989 | return 0; |
5990 | } | |
5991 | ||
96be4325 DB |
5992 | static bool may_access_skb(enum bpf_prog_type type) |
5993 | { | |
5994 | switch (type) { | |
5995 | case BPF_PROG_TYPE_SOCKET_FILTER: | |
5996 | case BPF_PROG_TYPE_SCHED_CLS: | |
94caee8c | 5997 | case BPF_PROG_TYPE_SCHED_ACT: |
96be4325 DB |
5998 | return true; |
5999 | default: | |
6000 | return false; | |
6001 | } | |
6002 | } | |
6003 | ||
ddd872bc AS |
6004 | /* verify safety of LD_ABS|LD_IND instructions: |
6005 | * - they can only appear in the programs where ctx == skb | |
6006 | * - since they are wrappers of function calls, they scratch R1-R5 registers, | |
6007 | * preserve R6-R9, and store return value into R0 | |
6008 | * | |
6009 | * Implicit input: | |
6010 | * ctx == skb == R6 == CTX | |
6011 | * | |
6012 | * Explicit input: | |
6013 | * SRC == any register | |
6014 | * IMM == 32-bit immediate | |
6015 | * | |
6016 | * Output: | |
6017 | * R0 - 8/16/32-bit skb data converted to cpu endianness | |
6018 | */ | |
58e2af8b | 6019 | static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) |
ddd872bc | 6020 | { |
638f5b90 | 6021 | struct bpf_reg_state *regs = cur_regs(env); |
ddd872bc | 6022 | u8 mode = BPF_MODE(insn->code); |
ddd872bc AS |
6023 | int i, err; |
6024 | ||
24701ece | 6025 | if (!may_access_skb(env->prog->type)) { |
61bd5218 | 6026 | verbose(env, "BPF_LD_[ABS|IND] instructions not allowed for this program type\n"); |
ddd872bc AS |
6027 | return -EINVAL; |
6028 | } | |
6029 | ||
e0cea7ce DB |
6030 | if (!env->ops->gen_ld_abs) { |
6031 | verbose(env, "bpf verifier is misconfigured\n"); | |
6032 | return -EINVAL; | |
6033 | } | |
6034 | ||
f910cefa | 6035 | if (env->subprog_cnt > 1) { |
f4d7e40a AS |
6036 | /* when program has LD_ABS insn JITs and interpreter assume |
6037 | * that r1 == ctx == skb which is not the case for callees | |
6038 | * that can have arbitrary arguments. It's problematic | |
6039 | * for main prog as well since JITs would need to analyze | |
6040 | * all functions in order to make proper register save/restore | |
6041 | * decisions in the main prog. Hence disallow LD_ABS with calls | |
6042 | */ | |
6043 | verbose(env, "BPF_LD_[ABS|IND] instructions cannot be mixed with bpf-to-bpf calls\n"); | |
6044 | return -EINVAL; | |
6045 | } | |
6046 | ||
ddd872bc | 6047 | if (insn->dst_reg != BPF_REG_0 || insn->off != 0 || |
d82bccc6 | 6048 | BPF_SIZE(insn->code) == BPF_DW || |
ddd872bc | 6049 | (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) { |
61bd5218 | 6050 | verbose(env, "BPF_LD_[ABS|IND] uses reserved fields\n"); |
ddd872bc AS |
6051 | return -EINVAL; |
6052 | } | |
6053 | ||
6054 | /* check whether implicit source operand (register R6) is readable */ | |
dc503a8a | 6055 | err = check_reg_arg(env, BPF_REG_6, SRC_OP); |
ddd872bc AS |
6056 | if (err) |
6057 | return err; | |
6058 | ||
fd978bf7 JS |
6059 | /* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as |
6060 | * gen_ld_abs() may terminate the program at runtime, leading to | |
6061 | * reference leak. | |
6062 | */ | |
6063 | err = check_reference_leak(env); | |
6064 | if (err) { | |
6065 | verbose(env, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n"); | |
6066 | return err; | |
6067 | } | |
6068 | ||
d83525ca AS |
6069 | if (env->cur_state->active_spin_lock) { |
6070 | verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n"); | |
6071 | return -EINVAL; | |
6072 | } | |
6073 | ||
ddd872bc | 6074 | if (regs[BPF_REG_6].type != PTR_TO_CTX) { |
61bd5218 JK |
6075 | verbose(env, |
6076 | "at the time of BPF_LD_ABS|IND R6 != pointer to skb\n"); | |
ddd872bc AS |
6077 | return -EINVAL; |
6078 | } | |
6079 | ||
6080 | if (mode == BPF_IND) { | |
6081 | /* check explicit source operand */ | |
dc503a8a | 6082 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
ddd872bc AS |
6083 | if (err) |
6084 | return err; | |
6085 | } | |
6086 | ||
6087 | /* reset caller saved regs to unreadable */ | |
dc503a8a | 6088 | for (i = 0; i < CALLER_SAVED_REGS; i++) { |
61bd5218 | 6089 | mark_reg_not_init(env, regs, caller_saved[i]); |
dc503a8a EC |
6090 | check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK); |
6091 | } | |
ddd872bc AS |
6092 | |
6093 | /* mark destination R0 register as readable, since it contains | |
dc503a8a EC |
6094 | * the value fetched from the packet. |
6095 | * Already marked as written above. | |
ddd872bc | 6096 | */ |
61bd5218 | 6097 | mark_reg_unknown(env, regs, BPF_REG_0); |
5327ed3d JW |
6098 | /* ld_abs load up to 32-bit skb data. */ |
6099 | regs[BPF_REG_0].subreg_def = env->insn_idx + 1; | |
ddd872bc AS |
6100 | return 0; |
6101 | } | |
6102 | ||
390ee7e2 AS |
6103 | static int check_return_code(struct bpf_verifier_env *env) |
6104 | { | |
5cf1e914 | 6105 | struct tnum enforce_attach_type_range = tnum_unknown; |
390ee7e2 AS |
6106 | struct bpf_reg_state *reg; |
6107 | struct tnum range = tnum_range(0, 1); | |
6108 | ||
6109 | switch (env->prog->type) { | |
983695fa DB |
6110 | case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: |
6111 | if (env->prog->expected_attach_type == BPF_CGROUP_UDP4_RECVMSG || | |
6112 | env->prog->expected_attach_type == BPF_CGROUP_UDP6_RECVMSG) | |
6113 | range = tnum_range(1, 1); | |
ed4ed404 | 6114 | break; |
390ee7e2 | 6115 | case BPF_PROG_TYPE_CGROUP_SKB: |
5cf1e914 | 6116 | if (env->prog->expected_attach_type == BPF_CGROUP_INET_EGRESS) { |
6117 | range = tnum_range(0, 3); | |
6118 | enforce_attach_type_range = tnum_range(2, 3); | |
6119 | } | |
ed4ed404 | 6120 | break; |
390ee7e2 AS |
6121 | case BPF_PROG_TYPE_CGROUP_SOCK: |
6122 | case BPF_PROG_TYPE_SOCK_OPS: | |
ebc614f6 | 6123 | case BPF_PROG_TYPE_CGROUP_DEVICE: |
7b146ceb | 6124 | case BPF_PROG_TYPE_CGROUP_SYSCTL: |
0d01da6a | 6125 | case BPF_PROG_TYPE_CGROUP_SOCKOPT: |
390ee7e2 AS |
6126 | break; |
6127 | default: | |
6128 | return 0; | |
6129 | } | |
6130 | ||
638f5b90 | 6131 | reg = cur_regs(env) + BPF_REG_0; |
390ee7e2 | 6132 | if (reg->type != SCALAR_VALUE) { |
61bd5218 | 6133 | verbose(env, "At program exit the register R0 is not a known value (%s)\n", |
390ee7e2 AS |
6134 | reg_type_str[reg->type]); |
6135 | return -EINVAL; | |
6136 | } | |
6137 | ||
6138 | if (!tnum_in(range, reg->var_off)) { | |
5cf1e914 | 6139 | char tn_buf[48]; |
6140 | ||
61bd5218 | 6141 | verbose(env, "At program exit the register R0 "); |
390ee7e2 | 6142 | if (!tnum_is_unknown(reg->var_off)) { |
390ee7e2 | 6143 | tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); |
61bd5218 | 6144 | verbose(env, "has value %s", tn_buf); |
390ee7e2 | 6145 | } else { |
61bd5218 | 6146 | verbose(env, "has unknown scalar value"); |
390ee7e2 | 6147 | } |
5cf1e914 | 6148 | tnum_strn(tn_buf, sizeof(tn_buf), range); |
983695fa | 6149 | verbose(env, " should have been in %s\n", tn_buf); |
390ee7e2 AS |
6150 | return -EINVAL; |
6151 | } | |
5cf1e914 | 6152 | |
6153 | if (!tnum_is_unknown(enforce_attach_type_range) && | |
6154 | tnum_in(enforce_attach_type_range, reg->var_off)) | |
6155 | env->prog->enforce_expected_attach_type = 1; | |
390ee7e2 AS |
6156 | return 0; |
6157 | } | |
6158 | ||
475fb78f AS |
6159 | /* non-recursive DFS pseudo code |
6160 | * 1 procedure DFS-iterative(G,v): | |
6161 | * 2 label v as discovered | |
6162 | * 3 let S be a stack | |
6163 | * 4 S.push(v) | |
6164 | * 5 while S is not empty | |
6165 | * 6 t <- S.pop() | |
6166 | * 7 if t is what we're looking for: | |
6167 | * 8 return t | |
6168 | * 9 for all edges e in G.adjacentEdges(t) do | |
6169 | * 10 if edge e is already labelled | |
6170 | * 11 continue with the next edge | |
6171 | * 12 w <- G.adjacentVertex(t,e) | |
6172 | * 13 if vertex w is not discovered and not explored | |
6173 | * 14 label e as tree-edge | |
6174 | * 15 label w as discovered | |
6175 | * 16 S.push(w) | |
6176 | * 17 continue at 5 | |
6177 | * 18 else if vertex w is discovered | |
6178 | * 19 label e as back-edge | |
6179 | * 20 else | |
6180 | * 21 // vertex w is explored | |
6181 | * 22 label e as forward- or cross-edge | |
6182 | * 23 label t as explored | |
6183 | * 24 S.pop() | |
6184 | * | |
6185 | * convention: | |
6186 | * 0x10 - discovered | |
6187 | * 0x11 - discovered and fall-through edge labelled | |
6188 | * 0x12 - discovered and fall-through and branch edges labelled | |
6189 | * 0x20 - explored | |
6190 | */ | |
6191 | ||
6192 | enum { | |
6193 | DISCOVERED = 0x10, | |
6194 | EXPLORED = 0x20, | |
6195 | FALLTHROUGH = 1, | |
6196 | BRANCH = 2, | |
6197 | }; | |
6198 | ||
dc2a4ebc AS |
6199 | static u32 state_htab_size(struct bpf_verifier_env *env) |
6200 | { | |
6201 | return env->prog->len; | |
6202 | } | |
6203 | ||
5d839021 AS |
6204 | static struct bpf_verifier_state_list **explored_state( |
6205 | struct bpf_verifier_env *env, | |
6206 | int idx) | |
6207 | { | |
dc2a4ebc AS |
6208 | struct bpf_verifier_state *cur = env->cur_state; |
6209 | struct bpf_func_state *state = cur->frame[cur->curframe]; | |
6210 | ||
6211 | return &env->explored_states[(idx ^ state->callsite) % state_htab_size(env)]; | |
5d839021 AS |
6212 | } |
6213 | ||
6214 | static void init_explored_state(struct bpf_verifier_env *env, int idx) | |
6215 | { | |
a8f500af | 6216 | env->insn_aux_data[idx].prune_point = true; |
5d839021 | 6217 | } |
f1bca824 | 6218 | |
475fb78f AS |
6219 | /* t, w, e - match pseudo-code above: |
6220 | * t - index of current instruction | |
6221 | * w - next instruction | |
6222 | * e - edge | |
6223 | */ | |
2589726d AS |
6224 | static int push_insn(int t, int w, int e, struct bpf_verifier_env *env, |
6225 | bool loop_ok) | |
475fb78f | 6226 | { |
7df737e9 AS |
6227 | int *insn_stack = env->cfg.insn_stack; |
6228 | int *insn_state = env->cfg.insn_state; | |
6229 | ||
475fb78f AS |
6230 | if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH)) |
6231 | return 0; | |
6232 | ||
6233 | if (e == BRANCH && insn_state[t] >= (DISCOVERED | BRANCH)) | |
6234 | return 0; | |
6235 | ||
6236 | if (w < 0 || w >= env->prog->len) { | |
d9762e84 | 6237 | verbose_linfo(env, t, "%d: ", t); |
61bd5218 | 6238 | verbose(env, "jump out of range from insn %d to %d\n", t, w); |
475fb78f AS |
6239 | return -EINVAL; |
6240 | } | |
6241 | ||
f1bca824 AS |
6242 | if (e == BRANCH) |
6243 | /* mark branch target for state pruning */ | |
5d839021 | 6244 | init_explored_state(env, w); |
f1bca824 | 6245 | |
475fb78f AS |
6246 | if (insn_state[w] == 0) { |
6247 | /* tree-edge */ | |
6248 | insn_state[t] = DISCOVERED | e; | |
6249 | insn_state[w] = DISCOVERED; | |
7df737e9 | 6250 | if (env->cfg.cur_stack >= env->prog->len) |
475fb78f | 6251 | return -E2BIG; |
7df737e9 | 6252 | insn_stack[env->cfg.cur_stack++] = w; |
475fb78f AS |
6253 | return 1; |
6254 | } else if ((insn_state[w] & 0xF0) == DISCOVERED) { | |
2589726d AS |
6255 | if (loop_ok && env->allow_ptr_leaks) |
6256 | return 0; | |
d9762e84 MKL |
6257 | verbose_linfo(env, t, "%d: ", t); |
6258 | verbose_linfo(env, w, "%d: ", w); | |
61bd5218 | 6259 | verbose(env, "back-edge from insn %d to %d\n", t, w); |
475fb78f AS |
6260 | return -EINVAL; |
6261 | } else if (insn_state[w] == EXPLORED) { | |
6262 | /* forward- or cross-edge */ | |
6263 | insn_state[t] = DISCOVERED | e; | |
6264 | } else { | |
61bd5218 | 6265 | verbose(env, "insn state internal bug\n"); |
475fb78f AS |
6266 | return -EFAULT; |
6267 | } | |
6268 | return 0; | |
6269 | } | |
6270 | ||
6271 | /* non-recursive depth-first-search to detect loops in BPF program | |
6272 | * loop == back-edge in directed graph | |
6273 | */ | |
58e2af8b | 6274 | static int check_cfg(struct bpf_verifier_env *env) |
475fb78f AS |
6275 | { |
6276 | struct bpf_insn *insns = env->prog->insnsi; | |
6277 | int insn_cnt = env->prog->len; | |
7df737e9 | 6278 | int *insn_stack, *insn_state; |
475fb78f AS |
6279 | int ret = 0; |
6280 | int i, t; | |
6281 | ||
7df737e9 | 6282 | insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL); |
475fb78f AS |
6283 | if (!insn_state) |
6284 | return -ENOMEM; | |
6285 | ||
7df737e9 | 6286 | insn_stack = env->cfg.insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL); |
475fb78f | 6287 | if (!insn_stack) { |
71dde681 | 6288 | kvfree(insn_state); |
475fb78f AS |
6289 | return -ENOMEM; |
6290 | } | |
6291 | ||
6292 | insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */ | |
6293 | insn_stack[0] = 0; /* 0 is the first instruction */ | |
7df737e9 | 6294 | env->cfg.cur_stack = 1; |
475fb78f AS |
6295 | |
6296 | peek_stack: | |
7df737e9 | 6297 | if (env->cfg.cur_stack == 0) |
475fb78f | 6298 | goto check_state; |
7df737e9 | 6299 | t = insn_stack[env->cfg.cur_stack - 1]; |
475fb78f | 6300 | |
092ed096 JW |
6301 | if (BPF_CLASS(insns[t].code) == BPF_JMP || |
6302 | BPF_CLASS(insns[t].code) == BPF_JMP32) { | |
475fb78f AS |
6303 | u8 opcode = BPF_OP(insns[t].code); |
6304 | ||
6305 | if (opcode == BPF_EXIT) { | |
6306 | goto mark_explored; | |
6307 | } else if (opcode == BPF_CALL) { | |
2589726d | 6308 | ret = push_insn(t, t + 1, FALLTHROUGH, env, false); |
475fb78f AS |
6309 | if (ret == 1) |
6310 | goto peek_stack; | |
6311 | else if (ret < 0) | |
6312 | goto err_free; | |
07016151 | 6313 | if (t + 1 < insn_cnt) |
5d839021 | 6314 | init_explored_state(env, t + 1); |
cc8b0b92 | 6315 | if (insns[t].src_reg == BPF_PSEUDO_CALL) { |
5d839021 | 6316 | init_explored_state(env, t); |
2589726d AS |
6317 | ret = push_insn(t, t + insns[t].imm + 1, BRANCH, |
6318 | env, false); | |
cc8b0b92 AS |
6319 | if (ret == 1) |
6320 | goto peek_stack; | |
6321 | else if (ret < 0) | |
6322 | goto err_free; | |
6323 | } | |
475fb78f AS |
6324 | } else if (opcode == BPF_JA) { |
6325 | if (BPF_SRC(insns[t].code) != BPF_K) { | |
6326 | ret = -EINVAL; | |
6327 | goto err_free; | |
6328 | } | |
6329 | /* unconditional jump with single edge */ | |
6330 | ret = push_insn(t, t + insns[t].off + 1, | |
2589726d | 6331 | FALLTHROUGH, env, true); |
475fb78f AS |
6332 | if (ret == 1) |
6333 | goto peek_stack; | |
6334 | else if (ret < 0) | |
6335 | goto err_free; | |
b5dc0163 AS |
6336 | /* unconditional jmp is not a good pruning point, |
6337 | * but it's marked, since backtracking needs | |
6338 | * to record jmp history in is_state_visited(). | |
6339 | */ | |
6340 | init_explored_state(env, t + insns[t].off + 1); | |
f1bca824 AS |
6341 | /* tell verifier to check for equivalent states |
6342 | * after every call and jump | |
6343 | */ | |
c3de6317 | 6344 | if (t + 1 < insn_cnt) |
5d839021 | 6345 | init_explored_state(env, t + 1); |
475fb78f AS |
6346 | } else { |
6347 | /* conditional jump with two edges */ | |
5d839021 | 6348 | init_explored_state(env, t); |
2589726d | 6349 | ret = push_insn(t, t + 1, FALLTHROUGH, env, true); |
475fb78f AS |
6350 | if (ret == 1) |
6351 | goto peek_stack; | |
6352 | else if (ret < 0) | |
6353 | goto err_free; | |
6354 | ||
2589726d | 6355 | ret = push_insn(t, t + insns[t].off + 1, BRANCH, env, true); |
475fb78f AS |
6356 | if (ret == 1) |
6357 | goto peek_stack; | |
6358 | else if (ret < 0) | |
6359 | goto err_free; | |
6360 | } | |
6361 | } else { | |
6362 | /* all other non-branch instructions with single | |
6363 | * fall-through edge | |
6364 | */ | |
2589726d | 6365 | ret = push_insn(t, t + 1, FALLTHROUGH, env, false); |
475fb78f AS |
6366 | if (ret == 1) |
6367 | goto peek_stack; | |
6368 | else if (ret < 0) | |
6369 | goto err_free; | |
6370 | } | |
6371 | ||
6372 | mark_explored: | |
6373 | insn_state[t] = EXPLORED; | |
7df737e9 | 6374 | if (env->cfg.cur_stack-- <= 0) { |
61bd5218 | 6375 | verbose(env, "pop stack internal bug\n"); |
475fb78f AS |
6376 | ret = -EFAULT; |
6377 | goto err_free; | |
6378 | } | |
6379 | goto peek_stack; | |
6380 | ||
6381 | check_state: | |
6382 | for (i = 0; i < insn_cnt; i++) { | |
6383 | if (insn_state[i] != EXPLORED) { | |
61bd5218 | 6384 | verbose(env, "unreachable insn %d\n", i); |
475fb78f AS |
6385 | ret = -EINVAL; |
6386 | goto err_free; | |
6387 | } | |
6388 | } | |
6389 | ret = 0; /* cfg looks good */ | |
6390 | ||
6391 | err_free: | |
71dde681 AS |
6392 | kvfree(insn_state); |
6393 | kvfree(insn_stack); | |
7df737e9 | 6394 | env->cfg.insn_state = env->cfg.insn_stack = NULL; |
475fb78f AS |
6395 | return ret; |
6396 | } | |
6397 | ||
838e9690 YS |
6398 | /* The minimum supported BTF func info size */ |
6399 | #define MIN_BPF_FUNCINFO_SIZE 8 | |
6400 | #define MAX_FUNCINFO_REC_SIZE 252 | |
6401 | ||
c454a46b MKL |
6402 | static int check_btf_func(struct bpf_verifier_env *env, |
6403 | const union bpf_attr *attr, | |
6404 | union bpf_attr __user *uattr) | |
838e9690 | 6405 | { |
d0b2818e | 6406 | u32 i, nfuncs, urec_size, min_size; |
838e9690 | 6407 | u32 krec_size = sizeof(struct bpf_func_info); |
c454a46b | 6408 | struct bpf_func_info *krecord; |
838e9690 | 6409 | const struct btf_type *type; |
c454a46b MKL |
6410 | struct bpf_prog *prog; |
6411 | const struct btf *btf; | |
838e9690 | 6412 | void __user *urecord; |
d0b2818e | 6413 | u32 prev_offset = 0; |
838e9690 YS |
6414 | int ret = 0; |
6415 | ||
6416 | nfuncs = attr->func_info_cnt; | |
6417 | if (!nfuncs) | |
6418 | return 0; | |
6419 | ||
6420 | if (nfuncs != env->subprog_cnt) { | |
6421 | verbose(env, "number of funcs in func_info doesn't match number of subprogs\n"); | |
6422 | return -EINVAL; | |
6423 | } | |
6424 | ||
6425 | urec_size = attr->func_info_rec_size; | |
6426 | if (urec_size < MIN_BPF_FUNCINFO_SIZE || | |
6427 | urec_size > MAX_FUNCINFO_REC_SIZE || | |
6428 | urec_size % sizeof(u32)) { | |
6429 | verbose(env, "invalid func info rec size %u\n", urec_size); | |
6430 | return -EINVAL; | |
6431 | } | |
6432 | ||
c454a46b MKL |
6433 | prog = env->prog; |
6434 | btf = prog->aux->btf; | |
838e9690 YS |
6435 | |
6436 | urecord = u64_to_user_ptr(attr->func_info); | |
6437 | min_size = min_t(u32, krec_size, urec_size); | |
6438 | ||
ba64e7d8 | 6439 | krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN); |
c454a46b MKL |
6440 | if (!krecord) |
6441 | return -ENOMEM; | |
ba64e7d8 | 6442 | |
838e9690 YS |
6443 | for (i = 0; i < nfuncs; i++) { |
6444 | ret = bpf_check_uarg_tail_zero(urecord, krec_size, urec_size); | |
6445 | if (ret) { | |
6446 | if (ret == -E2BIG) { | |
6447 | verbose(env, "nonzero tailing record in func info"); | |
6448 | /* set the size kernel expects so loader can zero | |
6449 | * out the rest of the record. | |
6450 | */ | |
6451 | if (put_user(min_size, &uattr->func_info_rec_size)) | |
6452 | ret = -EFAULT; | |
6453 | } | |
c454a46b | 6454 | goto err_free; |
838e9690 YS |
6455 | } |
6456 | ||
ba64e7d8 | 6457 | if (copy_from_user(&krecord[i], urecord, min_size)) { |
838e9690 | 6458 | ret = -EFAULT; |
c454a46b | 6459 | goto err_free; |
838e9690 YS |
6460 | } |
6461 | ||
d30d42e0 | 6462 | /* check insn_off */ |
838e9690 | 6463 | if (i == 0) { |
d30d42e0 | 6464 | if (krecord[i].insn_off) { |
838e9690 | 6465 | verbose(env, |
d30d42e0 MKL |
6466 | "nonzero insn_off %u for the first func info record", |
6467 | krecord[i].insn_off); | |
838e9690 | 6468 | ret = -EINVAL; |
c454a46b | 6469 | goto err_free; |
838e9690 | 6470 | } |
d30d42e0 | 6471 | } else if (krecord[i].insn_off <= prev_offset) { |
838e9690 YS |
6472 | verbose(env, |
6473 | "same or smaller insn offset (%u) than previous func info record (%u)", | |
d30d42e0 | 6474 | krecord[i].insn_off, prev_offset); |
838e9690 | 6475 | ret = -EINVAL; |
c454a46b | 6476 | goto err_free; |
838e9690 YS |
6477 | } |
6478 | ||
d30d42e0 | 6479 | if (env->subprog_info[i].start != krecord[i].insn_off) { |
838e9690 YS |
6480 | verbose(env, "func_info BTF section doesn't match subprog layout in BPF program\n"); |
6481 | ret = -EINVAL; | |
c454a46b | 6482 | goto err_free; |
838e9690 YS |
6483 | } |
6484 | ||
6485 | /* check type_id */ | |
ba64e7d8 | 6486 | type = btf_type_by_id(btf, krecord[i].type_id); |
838e9690 YS |
6487 | if (!type || BTF_INFO_KIND(type->info) != BTF_KIND_FUNC) { |
6488 | verbose(env, "invalid type id %d in func info", | |
ba64e7d8 | 6489 | krecord[i].type_id); |
838e9690 | 6490 | ret = -EINVAL; |
c454a46b | 6491 | goto err_free; |
838e9690 YS |
6492 | } |
6493 | ||
d30d42e0 | 6494 | prev_offset = krecord[i].insn_off; |
838e9690 YS |
6495 | urecord += urec_size; |
6496 | } | |
6497 | ||
ba64e7d8 YS |
6498 | prog->aux->func_info = krecord; |
6499 | prog->aux->func_info_cnt = nfuncs; | |
838e9690 YS |
6500 | return 0; |
6501 | ||
c454a46b | 6502 | err_free: |
ba64e7d8 | 6503 | kvfree(krecord); |
838e9690 YS |
6504 | return ret; |
6505 | } | |
6506 | ||
ba64e7d8 YS |
6507 | static void adjust_btf_func(struct bpf_verifier_env *env) |
6508 | { | |
6509 | int i; | |
6510 | ||
6511 | if (!env->prog->aux->func_info) | |
6512 | return; | |
6513 | ||
6514 | for (i = 0; i < env->subprog_cnt; i++) | |
d30d42e0 | 6515 | env->prog->aux->func_info[i].insn_off = env->subprog_info[i].start; |
ba64e7d8 YS |
6516 | } |
6517 | ||
c454a46b MKL |
6518 | #define MIN_BPF_LINEINFO_SIZE (offsetof(struct bpf_line_info, line_col) + \ |
6519 | sizeof(((struct bpf_line_info *)(0))->line_col)) | |
6520 | #define MAX_LINEINFO_REC_SIZE MAX_FUNCINFO_REC_SIZE | |
6521 | ||
6522 | static int check_btf_line(struct bpf_verifier_env *env, | |
6523 | const union bpf_attr *attr, | |
6524 | union bpf_attr __user *uattr) | |
6525 | { | |
6526 | u32 i, s, nr_linfo, ncopy, expected_size, rec_size, prev_offset = 0; | |
6527 | struct bpf_subprog_info *sub; | |
6528 | struct bpf_line_info *linfo; | |
6529 | struct bpf_prog *prog; | |
6530 | const struct btf *btf; | |
6531 | void __user *ulinfo; | |
6532 | int err; | |
6533 | ||
6534 | nr_linfo = attr->line_info_cnt; | |
6535 | if (!nr_linfo) | |
6536 | return 0; | |
6537 | ||
6538 | rec_size = attr->line_info_rec_size; | |
6539 | if (rec_size < MIN_BPF_LINEINFO_SIZE || | |
6540 | rec_size > MAX_LINEINFO_REC_SIZE || | |
6541 | rec_size & (sizeof(u32) - 1)) | |
6542 | return -EINVAL; | |
6543 | ||
6544 | /* Need to zero it in case the userspace may | |
6545 | * pass in a smaller bpf_line_info object. | |
6546 | */ | |
6547 | linfo = kvcalloc(nr_linfo, sizeof(struct bpf_line_info), | |
6548 | GFP_KERNEL | __GFP_NOWARN); | |
6549 | if (!linfo) | |
6550 | return -ENOMEM; | |
6551 | ||
6552 | prog = env->prog; | |
6553 | btf = prog->aux->btf; | |
6554 | ||
6555 | s = 0; | |
6556 | sub = env->subprog_info; | |
6557 | ulinfo = u64_to_user_ptr(attr->line_info); | |
6558 | expected_size = sizeof(struct bpf_line_info); | |
6559 | ncopy = min_t(u32, expected_size, rec_size); | |
6560 | for (i = 0; i < nr_linfo; i++) { | |
6561 | err = bpf_check_uarg_tail_zero(ulinfo, expected_size, rec_size); | |
6562 | if (err) { | |
6563 | if (err == -E2BIG) { | |
6564 | verbose(env, "nonzero tailing record in line_info"); | |
6565 | if (put_user(expected_size, | |
6566 | &uattr->line_info_rec_size)) | |
6567 | err = -EFAULT; | |
6568 | } | |
6569 | goto err_free; | |
6570 | } | |
6571 | ||
6572 | if (copy_from_user(&linfo[i], ulinfo, ncopy)) { | |
6573 | err = -EFAULT; | |
6574 | goto err_free; | |
6575 | } | |
6576 | ||
6577 | /* | |
6578 | * Check insn_off to ensure | |
6579 | * 1) strictly increasing AND | |
6580 | * 2) bounded by prog->len | |
6581 | * | |
6582 | * The linfo[0].insn_off == 0 check logically falls into | |
6583 | * the later "missing bpf_line_info for func..." case | |
6584 | * because the first linfo[0].insn_off must be the | |
6585 | * first sub also and the first sub must have | |
6586 | * subprog_info[0].start == 0. | |
6587 | */ | |
6588 | if ((i && linfo[i].insn_off <= prev_offset) || | |
6589 | linfo[i].insn_off >= prog->len) { | |
6590 | verbose(env, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n", | |
6591 | i, linfo[i].insn_off, prev_offset, | |
6592 | prog->len); | |
6593 | err = -EINVAL; | |
6594 | goto err_free; | |
6595 | } | |
6596 | ||
fdbaa0be MKL |
6597 | if (!prog->insnsi[linfo[i].insn_off].code) { |
6598 | verbose(env, | |
6599 | "Invalid insn code at line_info[%u].insn_off\n", | |
6600 | i); | |
6601 | err = -EINVAL; | |
6602 | goto err_free; | |
6603 | } | |
6604 | ||
23127b33 MKL |
6605 | if (!btf_name_by_offset(btf, linfo[i].line_off) || |
6606 | !btf_name_by_offset(btf, linfo[i].file_name_off)) { | |
c454a46b MKL |
6607 | verbose(env, "Invalid line_info[%u].line_off or .file_name_off\n", i); |
6608 | err = -EINVAL; | |
6609 | goto err_free; | |
6610 | } | |
6611 | ||
6612 | if (s != env->subprog_cnt) { | |
6613 | if (linfo[i].insn_off == sub[s].start) { | |
6614 | sub[s].linfo_idx = i; | |
6615 | s++; | |
6616 | } else if (sub[s].start < linfo[i].insn_off) { | |
6617 | verbose(env, "missing bpf_line_info for func#%u\n", s); | |
6618 | err = -EINVAL; | |
6619 | goto err_free; | |
6620 | } | |
6621 | } | |
6622 | ||
6623 | prev_offset = linfo[i].insn_off; | |
6624 | ulinfo += rec_size; | |
6625 | } | |
6626 | ||
6627 | if (s != env->subprog_cnt) { | |
6628 | verbose(env, "missing bpf_line_info for %u funcs starting from func#%u\n", | |
6629 | env->subprog_cnt - s, s); | |
6630 | err = -EINVAL; | |
6631 | goto err_free; | |
6632 | } | |
6633 | ||
6634 | prog->aux->linfo = linfo; | |
6635 | prog->aux->nr_linfo = nr_linfo; | |
6636 | ||
6637 | return 0; | |
6638 | ||
6639 | err_free: | |
6640 | kvfree(linfo); | |
6641 | return err; | |
6642 | } | |
6643 | ||
6644 | static int check_btf_info(struct bpf_verifier_env *env, | |
6645 | const union bpf_attr *attr, | |
6646 | union bpf_attr __user *uattr) | |
6647 | { | |
6648 | struct btf *btf; | |
6649 | int err; | |
6650 | ||
6651 | if (!attr->func_info_cnt && !attr->line_info_cnt) | |
6652 | return 0; | |
6653 | ||
6654 | btf = btf_get_by_fd(attr->prog_btf_fd); | |
6655 | if (IS_ERR(btf)) | |
6656 | return PTR_ERR(btf); | |
6657 | env->prog->aux->btf = btf; | |
6658 | ||
6659 | err = check_btf_func(env, attr, uattr); | |
6660 | if (err) | |
6661 | return err; | |
6662 | ||
6663 | err = check_btf_line(env, attr, uattr); | |
6664 | if (err) | |
6665 | return err; | |
6666 | ||
6667 | return 0; | |
ba64e7d8 YS |
6668 | } |
6669 | ||
f1174f77 EC |
6670 | /* check %cur's range satisfies %old's */ |
6671 | static bool range_within(struct bpf_reg_state *old, | |
6672 | struct bpf_reg_state *cur) | |
6673 | { | |
b03c9f9f EC |
6674 | return old->umin_value <= cur->umin_value && |
6675 | old->umax_value >= cur->umax_value && | |
6676 | old->smin_value <= cur->smin_value && | |
6677 | old->smax_value >= cur->smax_value; | |
f1174f77 EC |
6678 | } |
6679 | ||
6680 | /* Maximum number of register states that can exist at once */ | |
6681 | #define ID_MAP_SIZE (MAX_BPF_REG + MAX_BPF_STACK / BPF_REG_SIZE) | |
6682 | struct idpair { | |
6683 | u32 old; | |
6684 | u32 cur; | |
6685 | }; | |
6686 | ||
6687 | /* If in the old state two registers had the same id, then they need to have | |
6688 | * the same id in the new state as well. But that id could be different from | |
6689 | * the old state, so we need to track the mapping from old to new ids. | |
6690 | * Once we have seen that, say, a reg with old id 5 had new id 9, any subsequent | |
6691 | * regs with old id 5 must also have new id 9 for the new state to be safe. But | |
6692 | * regs with a different old id could still have new id 9, we don't care about | |
6693 | * that. | |
6694 | * So we look through our idmap to see if this old id has been seen before. If | |
6695 | * so, we require the new id to match; otherwise, we add the id pair to the map. | |
969bf05e | 6696 | */ |
f1174f77 | 6697 | static bool check_ids(u32 old_id, u32 cur_id, struct idpair *idmap) |
969bf05e | 6698 | { |
f1174f77 | 6699 | unsigned int i; |
969bf05e | 6700 | |
f1174f77 EC |
6701 | for (i = 0; i < ID_MAP_SIZE; i++) { |
6702 | if (!idmap[i].old) { | |
6703 | /* Reached an empty slot; haven't seen this id before */ | |
6704 | idmap[i].old = old_id; | |
6705 | idmap[i].cur = cur_id; | |
6706 | return true; | |
6707 | } | |
6708 | if (idmap[i].old == old_id) | |
6709 | return idmap[i].cur == cur_id; | |
6710 | } | |
6711 | /* We ran out of idmap slots, which should be impossible */ | |
6712 | WARN_ON_ONCE(1); | |
6713 | return false; | |
6714 | } | |
6715 | ||
9242b5f5 AS |
6716 | static void clean_func_state(struct bpf_verifier_env *env, |
6717 | struct bpf_func_state *st) | |
6718 | { | |
6719 | enum bpf_reg_liveness live; | |
6720 | int i, j; | |
6721 | ||
6722 | for (i = 0; i < BPF_REG_FP; i++) { | |
6723 | live = st->regs[i].live; | |
6724 | /* liveness must not touch this register anymore */ | |
6725 | st->regs[i].live |= REG_LIVE_DONE; | |
6726 | if (!(live & REG_LIVE_READ)) | |
6727 | /* since the register is unused, clear its state | |
6728 | * to make further comparison simpler | |
6729 | */ | |
6730 | __mark_reg_not_init(&st->regs[i]); | |
6731 | } | |
6732 | ||
6733 | for (i = 0; i < st->allocated_stack / BPF_REG_SIZE; i++) { | |
6734 | live = st->stack[i].spilled_ptr.live; | |
6735 | /* liveness must not touch this stack slot anymore */ | |
6736 | st->stack[i].spilled_ptr.live |= REG_LIVE_DONE; | |
6737 | if (!(live & REG_LIVE_READ)) { | |
6738 | __mark_reg_not_init(&st->stack[i].spilled_ptr); | |
6739 | for (j = 0; j < BPF_REG_SIZE; j++) | |
6740 | st->stack[i].slot_type[j] = STACK_INVALID; | |
6741 | } | |
6742 | } | |
6743 | } | |
6744 | ||
6745 | static void clean_verifier_state(struct bpf_verifier_env *env, | |
6746 | struct bpf_verifier_state *st) | |
6747 | { | |
6748 | int i; | |
6749 | ||
6750 | if (st->frame[0]->regs[0].live & REG_LIVE_DONE) | |
6751 | /* all regs in this state in all frames were already marked */ | |
6752 | return; | |
6753 | ||
6754 | for (i = 0; i <= st->curframe; i++) | |
6755 | clean_func_state(env, st->frame[i]); | |
6756 | } | |
6757 | ||
6758 | /* the parentage chains form a tree. | |
6759 | * the verifier states are added to state lists at given insn and | |
6760 | * pushed into state stack for future exploration. | |
6761 | * when the verifier reaches bpf_exit insn some of the verifer states | |
6762 | * stored in the state lists have their final liveness state already, | |
6763 | * but a lot of states will get revised from liveness point of view when | |
6764 | * the verifier explores other branches. | |
6765 | * Example: | |
6766 | * 1: r0 = 1 | |
6767 | * 2: if r1 == 100 goto pc+1 | |
6768 | * 3: r0 = 2 | |
6769 | * 4: exit | |
6770 | * when the verifier reaches exit insn the register r0 in the state list of | |
6771 | * insn 2 will be seen as !REG_LIVE_READ. Then the verifier pops the other_branch | |
6772 | * of insn 2 and goes exploring further. At the insn 4 it will walk the | |
6773 | * parentage chain from insn 4 into insn 2 and will mark r0 as REG_LIVE_READ. | |
6774 | * | |
6775 | * Since the verifier pushes the branch states as it sees them while exploring | |
6776 | * the program the condition of walking the branch instruction for the second | |
6777 | * time means that all states below this branch were already explored and | |
6778 | * their final liveness markes are already propagated. | |
6779 | * Hence when the verifier completes the search of state list in is_state_visited() | |
6780 | * we can call this clean_live_states() function to mark all liveness states | |
6781 | * as REG_LIVE_DONE to indicate that 'parent' pointers of 'struct bpf_reg_state' | |
6782 | * will not be used. | |
6783 | * This function also clears the registers and stack for states that !READ | |
6784 | * to simplify state merging. | |
6785 | * | |
6786 | * Important note here that walking the same branch instruction in the callee | |
6787 | * doesn't meant that the states are DONE. The verifier has to compare | |
6788 | * the callsites | |
6789 | */ | |
6790 | static void clean_live_states(struct bpf_verifier_env *env, int insn, | |
6791 | struct bpf_verifier_state *cur) | |
6792 | { | |
6793 | struct bpf_verifier_state_list *sl; | |
6794 | int i; | |
6795 | ||
5d839021 | 6796 | sl = *explored_state(env, insn); |
a8f500af | 6797 | while (sl) { |
2589726d AS |
6798 | if (sl->state.branches) |
6799 | goto next; | |
dc2a4ebc AS |
6800 | if (sl->state.insn_idx != insn || |
6801 | sl->state.curframe != cur->curframe) | |
9242b5f5 AS |
6802 | goto next; |
6803 | for (i = 0; i <= cur->curframe; i++) | |
6804 | if (sl->state.frame[i]->callsite != cur->frame[i]->callsite) | |
6805 | goto next; | |
6806 | clean_verifier_state(env, &sl->state); | |
6807 | next: | |
6808 | sl = sl->next; | |
6809 | } | |
6810 | } | |
6811 | ||
f1174f77 | 6812 | /* Returns true if (rold safe implies rcur safe) */ |
1b688a19 EC |
6813 | static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur, |
6814 | struct idpair *idmap) | |
f1174f77 | 6815 | { |
f4d7e40a AS |
6816 | bool equal; |
6817 | ||
dc503a8a EC |
6818 | if (!(rold->live & REG_LIVE_READ)) |
6819 | /* explored state didn't use this */ | |
6820 | return true; | |
6821 | ||
679c782d | 6822 | equal = memcmp(rold, rcur, offsetof(struct bpf_reg_state, parent)) == 0; |
f4d7e40a AS |
6823 | |
6824 | if (rold->type == PTR_TO_STACK) | |
6825 | /* two stack pointers are equal only if they're pointing to | |
6826 | * the same stack frame, since fp-8 in foo != fp-8 in bar | |
6827 | */ | |
6828 | return equal && rold->frameno == rcur->frameno; | |
6829 | ||
6830 | if (equal) | |
969bf05e AS |
6831 | return true; |
6832 | ||
f1174f77 EC |
6833 | if (rold->type == NOT_INIT) |
6834 | /* explored state can't have used this */ | |
969bf05e | 6835 | return true; |
f1174f77 EC |
6836 | if (rcur->type == NOT_INIT) |
6837 | return false; | |
6838 | switch (rold->type) { | |
6839 | case SCALAR_VALUE: | |
6840 | if (rcur->type == SCALAR_VALUE) { | |
b5dc0163 AS |
6841 | if (!rold->precise && !rcur->precise) |
6842 | return true; | |
f1174f77 EC |
6843 | /* new val must satisfy old val knowledge */ |
6844 | return range_within(rold, rcur) && | |
6845 | tnum_in(rold->var_off, rcur->var_off); | |
6846 | } else { | |
179d1c56 JH |
6847 | /* We're trying to use a pointer in place of a scalar. |
6848 | * Even if the scalar was unbounded, this could lead to | |
6849 | * pointer leaks because scalars are allowed to leak | |
6850 | * while pointers are not. We could make this safe in | |
6851 | * special cases if root is calling us, but it's | |
6852 | * probably not worth the hassle. | |
f1174f77 | 6853 | */ |
179d1c56 | 6854 | return false; |
f1174f77 EC |
6855 | } |
6856 | case PTR_TO_MAP_VALUE: | |
1b688a19 EC |
6857 | /* If the new min/max/var_off satisfy the old ones and |
6858 | * everything else matches, we are OK. | |
d83525ca AS |
6859 | * 'id' is not compared, since it's only used for maps with |
6860 | * bpf_spin_lock inside map element and in such cases if | |
6861 | * the rest of the prog is valid for one map element then | |
6862 | * it's valid for all map elements regardless of the key | |
6863 | * used in bpf_map_lookup() | |
1b688a19 EC |
6864 | */ |
6865 | return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 && | |
6866 | range_within(rold, rcur) && | |
6867 | tnum_in(rold->var_off, rcur->var_off); | |
f1174f77 EC |
6868 | case PTR_TO_MAP_VALUE_OR_NULL: |
6869 | /* a PTR_TO_MAP_VALUE could be safe to use as a | |
6870 | * PTR_TO_MAP_VALUE_OR_NULL into the same map. | |
6871 | * However, if the old PTR_TO_MAP_VALUE_OR_NULL then got NULL- | |
6872 | * checked, doing so could have affected others with the same | |
6873 | * id, and we can't check for that because we lost the id when | |
6874 | * we converted to a PTR_TO_MAP_VALUE. | |
6875 | */ | |
6876 | if (rcur->type != PTR_TO_MAP_VALUE_OR_NULL) | |
6877 | return false; | |
6878 | if (memcmp(rold, rcur, offsetof(struct bpf_reg_state, id))) | |
6879 | return false; | |
6880 | /* Check our ids match any regs they're supposed to */ | |
6881 | return check_ids(rold->id, rcur->id, idmap); | |
de8f3a83 | 6882 | case PTR_TO_PACKET_META: |
f1174f77 | 6883 | case PTR_TO_PACKET: |
de8f3a83 | 6884 | if (rcur->type != rold->type) |
f1174f77 EC |
6885 | return false; |
6886 | /* We must have at least as much range as the old ptr | |
6887 | * did, so that any accesses which were safe before are | |
6888 | * still safe. This is true even if old range < old off, | |
6889 | * since someone could have accessed through (ptr - k), or | |
6890 | * even done ptr -= k in a register, to get a safe access. | |
6891 | */ | |
6892 | if (rold->range > rcur->range) | |
6893 | return false; | |
6894 | /* If the offsets don't match, we can't trust our alignment; | |
6895 | * nor can we be sure that we won't fall out of range. | |
6896 | */ | |
6897 | if (rold->off != rcur->off) | |
6898 | return false; | |
6899 | /* id relations must be preserved */ | |
6900 | if (rold->id && !check_ids(rold->id, rcur->id, idmap)) | |
6901 | return false; | |
6902 | /* new val must satisfy old val knowledge */ | |
6903 | return range_within(rold, rcur) && | |
6904 | tnum_in(rold->var_off, rcur->var_off); | |
6905 | case PTR_TO_CTX: | |
6906 | case CONST_PTR_TO_MAP: | |
f1174f77 | 6907 | case PTR_TO_PACKET_END: |
d58e468b | 6908 | case PTR_TO_FLOW_KEYS: |
c64b7983 JS |
6909 | case PTR_TO_SOCKET: |
6910 | case PTR_TO_SOCKET_OR_NULL: | |
46f8bc92 MKL |
6911 | case PTR_TO_SOCK_COMMON: |
6912 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
655a51e5 MKL |
6913 | case PTR_TO_TCP_SOCK: |
6914 | case PTR_TO_TCP_SOCK_OR_NULL: | |
fada7fdc | 6915 | case PTR_TO_XDP_SOCK: |
f1174f77 EC |
6916 | /* Only valid matches are exact, which memcmp() above |
6917 | * would have accepted | |
6918 | */ | |
6919 | default: | |
6920 | /* Don't know what's going on, just say it's not safe */ | |
6921 | return false; | |
6922 | } | |
969bf05e | 6923 | |
f1174f77 EC |
6924 | /* Shouldn't get here; if we do, say it's not safe */ |
6925 | WARN_ON_ONCE(1); | |
969bf05e AS |
6926 | return false; |
6927 | } | |
6928 | ||
f4d7e40a AS |
6929 | static bool stacksafe(struct bpf_func_state *old, |
6930 | struct bpf_func_state *cur, | |
638f5b90 AS |
6931 | struct idpair *idmap) |
6932 | { | |
6933 | int i, spi; | |
6934 | ||
638f5b90 AS |
6935 | /* walk slots of the explored stack and ignore any additional |
6936 | * slots in the current stack, since explored(safe) state | |
6937 | * didn't use them | |
6938 | */ | |
6939 | for (i = 0; i < old->allocated_stack; i++) { | |
6940 | spi = i / BPF_REG_SIZE; | |
6941 | ||
b233920c AS |
6942 | if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ)) { |
6943 | i += BPF_REG_SIZE - 1; | |
cc2b14d5 | 6944 | /* explored state didn't use this */ |
fd05e57b | 6945 | continue; |
b233920c | 6946 | } |
cc2b14d5 | 6947 | |
638f5b90 AS |
6948 | if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_INVALID) |
6949 | continue; | |
19e2dbb7 AS |
6950 | |
6951 | /* explored stack has more populated slots than current stack | |
6952 | * and these slots were used | |
6953 | */ | |
6954 | if (i >= cur->allocated_stack) | |
6955 | return false; | |
6956 | ||
cc2b14d5 AS |
6957 | /* if old state was safe with misc data in the stack |
6958 | * it will be safe with zero-initialized stack. | |
6959 | * The opposite is not true | |
6960 | */ | |
6961 | if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC && | |
6962 | cur->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_ZERO) | |
6963 | continue; | |
638f5b90 AS |
6964 | if (old->stack[spi].slot_type[i % BPF_REG_SIZE] != |
6965 | cur->stack[spi].slot_type[i % BPF_REG_SIZE]) | |
6966 | /* Ex: old explored (safe) state has STACK_SPILL in | |
6967 | * this stack slot, but current has has STACK_MISC -> | |
6968 | * this verifier states are not equivalent, | |
6969 | * return false to continue verification of this path | |
6970 | */ | |
6971 | return false; | |
6972 | if (i % BPF_REG_SIZE) | |
6973 | continue; | |
6974 | if (old->stack[spi].slot_type[0] != STACK_SPILL) | |
6975 | continue; | |
6976 | if (!regsafe(&old->stack[spi].spilled_ptr, | |
6977 | &cur->stack[spi].spilled_ptr, | |
6978 | idmap)) | |
6979 | /* when explored and current stack slot are both storing | |
6980 | * spilled registers, check that stored pointers types | |
6981 | * are the same as well. | |
6982 | * Ex: explored safe path could have stored | |
6983 | * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8} | |
6984 | * but current path has stored: | |
6985 | * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16} | |
6986 | * such verifier states are not equivalent. | |
6987 | * return false to continue verification of this path | |
6988 | */ | |
6989 | return false; | |
6990 | } | |
6991 | return true; | |
6992 | } | |
6993 | ||
fd978bf7 JS |
6994 | static bool refsafe(struct bpf_func_state *old, struct bpf_func_state *cur) |
6995 | { | |
6996 | if (old->acquired_refs != cur->acquired_refs) | |
6997 | return false; | |
6998 | return !memcmp(old->refs, cur->refs, | |
6999 | sizeof(*old->refs) * old->acquired_refs); | |
7000 | } | |
7001 | ||
f1bca824 AS |
7002 | /* compare two verifier states |
7003 | * | |
7004 | * all states stored in state_list are known to be valid, since | |
7005 | * verifier reached 'bpf_exit' instruction through them | |
7006 | * | |
7007 | * this function is called when verifier exploring different branches of | |
7008 | * execution popped from the state stack. If it sees an old state that has | |
7009 | * more strict register state and more strict stack state then this execution | |
7010 | * branch doesn't need to be explored further, since verifier already | |
7011 | * concluded that more strict state leads to valid finish. | |
7012 | * | |
7013 | * Therefore two states are equivalent if register state is more conservative | |
7014 | * and explored stack state is more conservative than the current one. | |
7015 | * Example: | |
7016 | * explored current | |
7017 | * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC) | |
7018 | * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC) | |
7019 | * | |
7020 | * In other words if current stack state (one being explored) has more | |
7021 | * valid slots than old one that already passed validation, it means | |
7022 | * the verifier can stop exploring and conclude that current state is valid too | |
7023 | * | |
7024 | * Similarly with registers. If explored state has register type as invalid | |
7025 | * whereas register type in current state is meaningful, it means that | |
7026 | * the current state will reach 'bpf_exit' instruction safely | |
7027 | */ | |
f4d7e40a AS |
7028 | static bool func_states_equal(struct bpf_func_state *old, |
7029 | struct bpf_func_state *cur) | |
f1bca824 | 7030 | { |
f1174f77 EC |
7031 | struct idpair *idmap; |
7032 | bool ret = false; | |
f1bca824 AS |
7033 | int i; |
7034 | ||
f1174f77 EC |
7035 | idmap = kcalloc(ID_MAP_SIZE, sizeof(struct idpair), GFP_KERNEL); |
7036 | /* If we failed to allocate the idmap, just say it's not safe */ | |
7037 | if (!idmap) | |
1a0dc1ac | 7038 | return false; |
f1174f77 EC |
7039 | |
7040 | for (i = 0; i < MAX_BPF_REG; i++) { | |
1b688a19 | 7041 | if (!regsafe(&old->regs[i], &cur->regs[i], idmap)) |
f1174f77 | 7042 | goto out_free; |
f1bca824 AS |
7043 | } |
7044 | ||
638f5b90 AS |
7045 | if (!stacksafe(old, cur, idmap)) |
7046 | goto out_free; | |
fd978bf7 JS |
7047 | |
7048 | if (!refsafe(old, cur)) | |
7049 | goto out_free; | |
f1174f77 EC |
7050 | ret = true; |
7051 | out_free: | |
7052 | kfree(idmap); | |
7053 | return ret; | |
f1bca824 AS |
7054 | } |
7055 | ||
f4d7e40a AS |
7056 | static bool states_equal(struct bpf_verifier_env *env, |
7057 | struct bpf_verifier_state *old, | |
7058 | struct bpf_verifier_state *cur) | |
7059 | { | |
7060 | int i; | |
7061 | ||
7062 | if (old->curframe != cur->curframe) | |
7063 | return false; | |
7064 | ||
979d63d5 DB |
7065 | /* Verification state from speculative execution simulation |
7066 | * must never prune a non-speculative execution one. | |
7067 | */ | |
7068 | if (old->speculative && !cur->speculative) | |
7069 | return false; | |
7070 | ||
d83525ca AS |
7071 | if (old->active_spin_lock != cur->active_spin_lock) |
7072 | return false; | |
7073 | ||
f4d7e40a AS |
7074 | /* for states to be equal callsites have to be the same |
7075 | * and all frame states need to be equivalent | |
7076 | */ | |
7077 | for (i = 0; i <= old->curframe; i++) { | |
7078 | if (old->frame[i]->callsite != cur->frame[i]->callsite) | |
7079 | return false; | |
7080 | if (!func_states_equal(old->frame[i], cur->frame[i])) | |
7081 | return false; | |
7082 | } | |
7083 | return true; | |
7084 | } | |
7085 | ||
5327ed3d JW |
7086 | /* Return 0 if no propagation happened. Return negative error code if error |
7087 | * happened. Otherwise, return the propagated bit. | |
7088 | */ | |
55e7f3b5 JW |
7089 | static int propagate_liveness_reg(struct bpf_verifier_env *env, |
7090 | struct bpf_reg_state *reg, | |
7091 | struct bpf_reg_state *parent_reg) | |
7092 | { | |
5327ed3d JW |
7093 | u8 parent_flag = parent_reg->live & REG_LIVE_READ; |
7094 | u8 flag = reg->live & REG_LIVE_READ; | |
55e7f3b5 JW |
7095 | int err; |
7096 | ||
5327ed3d JW |
7097 | /* When comes here, read flags of PARENT_REG or REG could be any of |
7098 | * REG_LIVE_READ64, REG_LIVE_READ32, REG_LIVE_NONE. There is no need | |
7099 | * of propagation if PARENT_REG has strongest REG_LIVE_READ64. | |
7100 | */ | |
7101 | if (parent_flag == REG_LIVE_READ64 || | |
7102 | /* Or if there is no read flag from REG. */ | |
7103 | !flag || | |
7104 | /* Or if the read flag from REG is the same as PARENT_REG. */ | |
7105 | parent_flag == flag) | |
55e7f3b5 JW |
7106 | return 0; |
7107 | ||
5327ed3d | 7108 | err = mark_reg_read(env, reg, parent_reg, flag); |
55e7f3b5 JW |
7109 | if (err) |
7110 | return err; | |
7111 | ||
5327ed3d | 7112 | return flag; |
55e7f3b5 JW |
7113 | } |
7114 | ||
8e9cd9ce | 7115 | /* A write screens off any subsequent reads; but write marks come from the |
f4d7e40a AS |
7116 | * straight-line code between a state and its parent. When we arrive at an |
7117 | * equivalent state (jump target or such) we didn't arrive by the straight-line | |
7118 | * code, so read marks in the state must propagate to the parent regardless | |
7119 | * of the state's write marks. That's what 'parent == state->parent' comparison | |
679c782d | 7120 | * in mark_reg_read() is for. |
8e9cd9ce | 7121 | */ |
f4d7e40a AS |
7122 | static int propagate_liveness(struct bpf_verifier_env *env, |
7123 | const struct bpf_verifier_state *vstate, | |
7124 | struct bpf_verifier_state *vparent) | |
dc503a8a | 7125 | { |
3f8cafa4 | 7126 | struct bpf_reg_state *state_reg, *parent_reg; |
f4d7e40a | 7127 | struct bpf_func_state *state, *parent; |
3f8cafa4 | 7128 | int i, frame, err = 0; |
dc503a8a | 7129 | |
f4d7e40a AS |
7130 | if (vparent->curframe != vstate->curframe) { |
7131 | WARN(1, "propagate_live: parent frame %d current frame %d\n", | |
7132 | vparent->curframe, vstate->curframe); | |
7133 | return -EFAULT; | |
7134 | } | |
dc503a8a EC |
7135 | /* Propagate read liveness of registers... */ |
7136 | BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG); | |
83d16312 | 7137 | for (frame = 0; frame <= vstate->curframe; frame++) { |
3f8cafa4 JW |
7138 | parent = vparent->frame[frame]; |
7139 | state = vstate->frame[frame]; | |
7140 | parent_reg = parent->regs; | |
7141 | state_reg = state->regs; | |
83d16312 JK |
7142 | /* We don't need to worry about FP liveness, it's read-only */ |
7143 | for (i = frame < vstate->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) { | |
55e7f3b5 JW |
7144 | err = propagate_liveness_reg(env, &state_reg[i], |
7145 | &parent_reg[i]); | |
5327ed3d | 7146 | if (err < 0) |
3f8cafa4 | 7147 | return err; |
5327ed3d JW |
7148 | if (err == REG_LIVE_READ64) |
7149 | mark_insn_zext(env, &parent_reg[i]); | |
dc503a8a | 7150 | } |
f4d7e40a | 7151 | |
1b04aee7 | 7152 | /* Propagate stack slots. */ |
f4d7e40a AS |
7153 | for (i = 0; i < state->allocated_stack / BPF_REG_SIZE && |
7154 | i < parent->allocated_stack / BPF_REG_SIZE; i++) { | |
3f8cafa4 JW |
7155 | parent_reg = &parent->stack[i].spilled_ptr; |
7156 | state_reg = &state->stack[i].spilled_ptr; | |
55e7f3b5 JW |
7157 | err = propagate_liveness_reg(env, state_reg, |
7158 | parent_reg); | |
5327ed3d | 7159 | if (err < 0) |
3f8cafa4 | 7160 | return err; |
dc503a8a EC |
7161 | } |
7162 | } | |
5327ed3d | 7163 | return 0; |
dc503a8a EC |
7164 | } |
7165 | ||
a3ce685d AS |
7166 | /* find precise scalars in the previous equivalent state and |
7167 | * propagate them into the current state | |
7168 | */ | |
7169 | static int propagate_precision(struct bpf_verifier_env *env, | |
7170 | const struct bpf_verifier_state *old) | |
7171 | { | |
7172 | struct bpf_reg_state *state_reg; | |
7173 | struct bpf_func_state *state; | |
7174 | int i, err = 0; | |
7175 | ||
7176 | state = old->frame[old->curframe]; | |
7177 | state_reg = state->regs; | |
7178 | for (i = 0; i < BPF_REG_FP; i++, state_reg++) { | |
7179 | if (state_reg->type != SCALAR_VALUE || | |
7180 | !state_reg->precise) | |
7181 | continue; | |
7182 | if (env->log.level & BPF_LOG_LEVEL2) | |
7183 | verbose(env, "propagating r%d\n", i); | |
7184 | err = mark_chain_precision(env, i); | |
7185 | if (err < 0) | |
7186 | return err; | |
7187 | } | |
7188 | ||
7189 | for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) { | |
7190 | if (state->stack[i].slot_type[0] != STACK_SPILL) | |
7191 | continue; | |
7192 | state_reg = &state->stack[i].spilled_ptr; | |
7193 | if (state_reg->type != SCALAR_VALUE || | |
7194 | !state_reg->precise) | |
7195 | continue; | |
7196 | if (env->log.level & BPF_LOG_LEVEL2) | |
7197 | verbose(env, "propagating fp%d\n", | |
7198 | (-i - 1) * BPF_REG_SIZE); | |
7199 | err = mark_chain_precision_stack(env, i); | |
7200 | if (err < 0) | |
7201 | return err; | |
7202 | } | |
7203 | return 0; | |
7204 | } | |
7205 | ||
2589726d AS |
7206 | static bool states_maybe_looping(struct bpf_verifier_state *old, |
7207 | struct bpf_verifier_state *cur) | |
7208 | { | |
7209 | struct bpf_func_state *fold, *fcur; | |
7210 | int i, fr = cur->curframe; | |
7211 | ||
7212 | if (old->curframe != fr) | |
7213 | return false; | |
7214 | ||
7215 | fold = old->frame[fr]; | |
7216 | fcur = cur->frame[fr]; | |
7217 | for (i = 0; i < MAX_BPF_REG; i++) | |
7218 | if (memcmp(&fold->regs[i], &fcur->regs[i], | |
7219 | offsetof(struct bpf_reg_state, parent))) | |
7220 | return false; | |
7221 | return true; | |
7222 | } | |
7223 | ||
7224 | ||
58e2af8b | 7225 | static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) |
f1bca824 | 7226 | { |
58e2af8b | 7227 | struct bpf_verifier_state_list *new_sl; |
9f4686c4 | 7228 | struct bpf_verifier_state_list *sl, **pprev; |
679c782d | 7229 | struct bpf_verifier_state *cur = env->cur_state, *new; |
ceefbc96 | 7230 | int i, j, err, states_cnt = 0; |
10d274e8 | 7231 | bool add_new_state = env->test_state_freq ? true : false; |
f1bca824 | 7232 | |
b5dc0163 | 7233 | cur->last_insn_idx = env->prev_insn_idx; |
a8f500af | 7234 | if (!env->insn_aux_data[insn_idx].prune_point) |
f1bca824 AS |
7235 | /* this 'insn_idx' instruction wasn't marked, so we will not |
7236 | * be doing state search here | |
7237 | */ | |
7238 | return 0; | |
7239 | ||
2589726d AS |
7240 | /* bpf progs typically have pruning point every 4 instructions |
7241 | * http://vger.kernel.org/bpfconf2019.html#session-1 | |
7242 | * Do not add new state for future pruning if the verifier hasn't seen | |
7243 | * at least 2 jumps and at least 8 instructions. | |
7244 | * This heuristics helps decrease 'total_states' and 'peak_states' metric. | |
7245 | * In tests that amounts to up to 50% reduction into total verifier | |
7246 | * memory consumption and 20% verifier time speedup. | |
7247 | */ | |
7248 | if (env->jmps_processed - env->prev_jmps_processed >= 2 && | |
7249 | env->insn_processed - env->prev_insn_processed >= 8) | |
7250 | add_new_state = true; | |
7251 | ||
a8f500af AS |
7252 | pprev = explored_state(env, insn_idx); |
7253 | sl = *pprev; | |
7254 | ||
9242b5f5 AS |
7255 | clean_live_states(env, insn_idx, cur); |
7256 | ||
a8f500af | 7257 | while (sl) { |
dc2a4ebc AS |
7258 | states_cnt++; |
7259 | if (sl->state.insn_idx != insn_idx) | |
7260 | goto next; | |
2589726d AS |
7261 | if (sl->state.branches) { |
7262 | if (states_maybe_looping(&sl->state, cur) && | |
7263 | states_equal(env, &sl->state, cur)) { | |
7264 | verbose_linfo(env, insn_idx, "; "); | |
7265 | verbose(env, "infinite loop detected at insn %d\n", insn_idx); | |
7266 | return -EINVAL; | |
7267 | } | |
7268 | /* if the verifier is processing a loop, avoid adding new state | |
7269 | * too often, since different loop iterations have distinct | |
7270 | * states and may not help future pruning. | |
7271 | * This threshold shouldn't be too low to make sure that | |
7272 | * a loop with large bound will be rejected quickly. | |
7273 | * The most abusive loop will be: | |
7274 | * r1 += 1 | |
7275 | * if r1 < 1000000 goto pc-2 | |
7276 | * 1M insn_procssed limit / 100 == 10k peak states. | |
7277 | * This threshold shouldn't be too high either, since states | |
7278 | * at the end of the loop are likely to be useful in pruning. | |
7279 | */ | |
7280 | if (env->jmps_processed - env->prev_jmps_processed < 20 && | |
7281 | env->insn_processed - env->prev_insn_processed < 100) | |
7282 | add_new_state = false; | |
7283 | goto miss; | |
7284 | } | |
638f5b90 | 7285 | if (states_equal(env, &sl->state, cur)) { |
9f4686c4 | 7286 | sl->hit_cnt++; |
f1bca824 | 7287 | /* reached equivalent register/stack state, |
dc503a8a EC |
7288 | * prune the search. |
7289 | * Registers read by the continuation are read by us. | |
8e9cd9ce EC |
7290 | * If we have any write marks in env->cur_state, they |
7291 | * will prevent corresponding reads in the continuation | |
7292 | * from reaching our parent (an explored_state). Our | |
7293 | * own state will get the read marks recorded, but | |
7294 | * they'll be immediately forgotten as we're pruning | |
7295 | * this state and will pop a new one. | |
f1bca824 | 7296 | */ |
f4d7e40a | 7297 | err = propagate_liveness(env, &sl->state, cur); |
a3ce685d AS |
7298 | |
7299 | /* if previous state reached the exit with precision and | |
7300 | * current state is equivalent to it (except precsion marks) | |
7301 | * the precision needs to be propagated back in | |
7302 | * the current state. | |
7303 | */ | |
7304 | err = err ? : push_jmp_history(env, cur); | |
7305 | err = err ? : propagate_precision(env, &sl->state); | |
f4d7e40a AS |
7306 | if (err) |
7307 | return err; | |
f1bca824 | 7308 | return 1; |
dc503a8a | 7309 | } |
2589726d AS |
7310 | miss: |
7311 | /* when new state is not going to be added do not increase miss count. | |
7312 | * Otherwise several loop iterations will remove the state | |
7313 | * recorded earlier. The goal of these heuristics is to have | |
7314 | * states from some iterations of the loop (some in the beginning | |
7315 | * and some at the end) to help pruning. | |
7316 | */ | |
7317 | if (add_new_state) | |
7318 | sl->miss_cnt++; | |
9f4686c4 AS |
7319 | /* heuristic to determine whether this state is beneficial |
7320 | * to keep checking from state equivalence point of view. | |
7321 | * Higher numbers increase max_states_per_insn and verification time, | |
7322 | * but do not meaningfully decrease insn_processed. | |
7323 | */ | |
7324 | if (sl->miss_cnt > sl->hit_cnt * 3 + 3) { | |
7325 | /* the state is unlikely to be useful. Remove it to | |
7326 | * speed up verification | |
7327 | */ | |
7328 | *pprev = sl->next; | |
7329 | if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE) { | |
2589726d AS |
7330 | u32 br = sl->state.branches; |
7331 | ||
7332 | WARN_ONCE(br, | |
7333 | "BUG live_done but branches_to_explore %d\n", | |
7334 | br); | |
9f4686c4 AS |
7335 | free_verifier_state(&sl->state, false); |
7336 | kfree(sl); | |
7337 | env->peak_states--; | |
7338 | } else { | |
7339 | /* cannot free this state, since parentage chain may | |
7340 | * walk it later. Add it for free_list instead to | |
7341 | * be freed at the end of verification | |
7342 | */ | |
7343 | sl->next = env->free_list; | |
7344 | env->free_list = sl; | |
7345 | } | |
7346 | sl = *pprev; | |
7347 | continue; | |
7348 | } | |
dc2a4ebc | 7349 | next: |
9f4686c4 AS |
7350 | pprev = &sl->next; |
7351 | sl = *pprev; | |
f1bca824 AS |
7352 | } |
7353 | ||
06ee7115 AS |
7354 | if (env->max_states_per_insn < states_cnt) |
7355 | env->max_states_per_insn = states_cnt; | |
7356 | ||
ceefbc96 | 7357 | if (!env->allow_ptr_leaks && states_cnt > BPF_COMPLEXITY_LIMIT_STATES) |
b5dc0163 | 7358 | return push_jmp_history(env, cur); |
ceefbc96 | 7359 | |
2589726d | 7360 | if (!add_new_state) |
b5dc0163 | 7361 | return push_jmp_history(env, cur); |
ceefbc96 | 7362 | |
2589726d AS |
7363 | /* There were no equivalent states, remember the current one. |
7364 | * Technically the current state is not proven to be safe yet, | |
f4d7e40a | 7365 | * but it will either reach outer most bpf_exit (which means it's safe) |
2589726d | 7366 | * or it will be rejected. When there are no loops the verifier won't be |
f4d7e40a | 7367 | * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx) |
2589726d AS |
7368 | * again on the way to bpf_exit. |
7369 | * When looping the sl->state.branches will be > 0 and this state | |
7370 | * will not be considered for equivalence until branches == 0. | |
f1bca824 | 7371 | */ |
638f5b90 | 7372 | new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL); |
f1bca824 AS |
7373 | if (!new_sl) |
7374 | return -ENOMEM; | |
06ee7115 AS |
7375 | env->total_states++; |
7376 | env->peak_states++; | |
2589726d AS |
7377 | env->prev_jmps_processed = env->jmps_processed; |
7378 | env->prev_insn_processed = env->insn_processed; | |
f1bca824 AS |
7379 | |
7380 | /* add new state to the head of linked list */ | |
679c782d EC |
7381 | new = &new_sl->state; |
7382 | err = copy_verifier_state(new, cur); | |
1969db47 | 7383 | if (err) { |
679c782d | 7384 | free_verifier_state(new, false); |
1969db47 AS |
7385 | kfree(new_sl); |
7386 | return err; | |
7387 | } | |
dc2a4ebc | 7388 | new->insn_idx = insn_idx; |
2589726d AS |
7389 | WARN_ONCE(new->branches != 1, |
7390 | "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches, insn_idx); | |
b5dc0163 | 7391 | |
2589726d | 7392 | cur->parent = new; |
b5dc0163 AS |
7393 | cur->first_insn_idx = insn_idx; |
7394 | clear_jmp_history(cur); | |
5d839021 AS |
7395 | new_sl->next = *explored_state(env, insn_idx); |
7396 | *explored_state(env, insn_idx) = new_sl; | |
7640ead9 JK |
7397 | /* connect new state to parentage chain. Current frame needs all |
7398 | * registers connected. Only r6 - r9 of the callers are alive (pushed | |
7399 | * to the stack implicitly by JITs) so in callers' frames connect just | |
7400 | * r6 - r9 as an optimization. Callers will have r1 - r5 connected to | |
7401 | * the state of the call instruction (with WRITTEN set), and r0 comes | |
7402 | * from callee with its full parentage chain, anyway. | |
7403 | */ | |
8e9cd9ce EC |
7404 | /* clear write marks in current state: the writes we did are not writes |
7405 | * our child did, so they don't screen off its reads from us. | |
7406 | * (There are no read marks in current state, because reads always mark | |
7407 | * their parent and current state never has children yet. Only | |
7408 | * explored_states can get read marks.) | |
7409 | */ | |
eea1c227 AS |
7410 | for (j = 0; j <= cur->curframe; j++) { |
7411 | for (i = j < cur->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) | |
7412 | cur->frame[j]->regs[i].parent = &new->frame[j]->regs[i]; | |
7413 | for (i = 0; i < BPF_REG_FP; i++) | |
7414 | cur->frame[j]->regs[i].live = REG_LIVE_NONE; | |
7415 | } | |
f4d7e40a AS |
7416 | |
7417 | /* all stack frames are accessible from callee, clear them all */ | |
7418 | for (j = 0; j <= cur->curframe; j++) { | |
7419 | struct bpf_func_state *frame = cur->frame[j]; | |
679c782d | 7420 | struct bpf_func_state *newframe = new->frame[j]; |
f4d7e40a | 7421 | |
679c782d | 7422 | for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++) { |
cc2b14d5 | 7423 | frame->stack[i].spilled_ptr.live = REG_LIVE_NONE; |
679c782d EC |
7424 | frame->stack[i].spilled_ptr.parent = |
7425 | &newframe->stack[i].spilled_ptr; | |
7426 | } | |
f4d7e40a | 7427 | } |
f1bca824 AS |
7428 | return 0; |
7429 | } | |
7430 | ||
c64b7983 JS |
7431 | /* Return true if it's OK to have the same insn return a different type. */ |
7432 | static bool reg_type_mismatch_ok(enum bpf_reg_type type) | |
7433 | { | |
7434 | switch (type) { | |
7435 | case PTR_TO_CTX: | |
7436 | case PTR_TO_SOCKET: | |
7437 | case PTR_TO_SOCKET_OR_NULL: | |
46f8bc92 MKL |
7438 | case PTR_TO_SOCK_COMMON: |
7439 | case PTR_TO_SOCK_COMMON_OR_NULL: | |
655a51e5 MKL |
7440 | case PTR_TO_TCP_SOCK: |
7441 | case PTR_TO_TCP_SOCK_OR_NULL: | |
fada7fdc | 7442 | case PTR_TO_XDP_SOCK: |
c64b7983 JS |
7443 | return false; |
7444 | default: | |
7445 | return true; | |
7446 | } | |
7447 | } | |
7448 | ||
7449 | /* If an instruction was previously used with particular pointer types, then we | |
7450 | * need to be careful to avoid cases such as the below, where it may be ok | |
7451 | * for one branch accessing the pointer, but not ok for the other branch: | |
7452 | * | |
7453 | * R1 = sock_ptr | |
7454 | * goto X; | |
7455 | * ... | |
7456 | * R1 = some_other_valid_ptr; | |
7457 | * goto X; | |
7458 | * ... | |
7459 | * R2 = *(u32 *)(R1 + 0); | |
7460 | */ | |
7461 | static bool reg_type_mismatch(enum bpf_reg_type src, enum bpf_reg_type prev) | |
7462 | { | |
7463 | return src != prev && (!reg_type_mismatch_ok(src) || | |
7464 | !reg_type_mismatch_ok(prev)); | |
7465 | } | |
7466 | ||
58e2af8b | 7467 | static int do_check(struct bpf_verifier_env *env) |
17a52670 | 7468 | { |
638f5b90 | 7469 | struct bpf_verifier_state *state; |
17a52670 | 7470 | struct bpf_insn *insns = env->prog->insnsi; |
638f5b90 | 7471 | struct bpf_reg_state *regs; |
06ee7115 | 7472 | int insn_cnt = env->prog->len; |
17a52670 | 7473 | bool do_print_state = false; |
b5dc0163 | 7474 | int prev_insn_idx = -1; |
17a52670 | 7475 | |
d9762e84 MKL |
7476 | env->prev_linfo = NULL; |
7477 | ||
638f5b90 AS |
7478 | state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL); |
7479 | if (!state) | |
7480 | return -ENOMEM; | |
f4d7e40a | 7481 | state->curframe = 0; |
979d63d5 | 7482 | state->speculative = false; |
2589726d | 7483 | state->branches = 1; |
f4d7e40a AS |
7484 | state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL); |
7485 | if (!state->frame[0]) { | |
7486 | kfree(state); | |
7487 | return -ENOMEM; | |
7488 | } | |
7489 | env->cur_state = state; | |
7490 | init_func_state(env, state->frame[0], | |
7491 | BPF_MAIN_FUNC /* callsite */, | |
7492 | 0 /* frameno */, | |
7493 | 0 /* subprogno, zero == main subprog */); | |
c08435ec | 7494 | |
17a52670 AS |
7495 | for (;;) { |
7496 | struct bpf_insn *insn; | |
7497 | u8 class; | |
7498 | int err; | |
7499 | ||
b5dc0163 | 7500 | env->prev_insn_idx = prev_insn_idx; |
c08435ec | 7501 | if (env->insn_idx >= insn_cnt) { |
61bd5218 | 7502 | verbose(env, "invalid insn idx %d insn_cnt %d\n", |
c08435ec | 7503 | env->insn_idx, insn_cnt); |
17a52670 AS |
7504 | return -EFAULT; |
7505 | } | |
7506 | ||
c08435ec | 7507 | insn = &insns[env->insn_idx]; |
17a52670 AS |
7508 | class = BPF_CLASS(insn->code); |
7509 | ||
06ee7115 | 7510 | if (++env->insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) { |
61bd5218 JK |
7511 | verbose(env, |
7512 | "BPF program is too large. Processed %d insn\n", | |
06ee7115 | 7513 | env->insn_processed); |
17a52670 AS |
7514 | return -E2BIG; |
7515 | } | |
7516 | ||
c08435ec | 7517 | err = is_state_visited(env, env->insn_idx); |
f1bca824 AS |
7518 | if (err < 0) |
7519 | return err; | |
7520 | if (err == 1) { | |
7521 | /* found equivalent state, can prune the search */ | |
06ee7115 | 7522 | if (env->log.level & BPF_LOG_LEVEL) { |
f1bca824 | 7523 | if (do_print_state) |
979d63d5 DB |
7524 | verbose(env, "\nfrom %d to %d%s: safe\n", |
7525 | env->prev_insn_idx, env->insn_idx, | |
7526 | env->cur_state->speculative ? | |
7527 | " (speculative execution)" : ""); | |
f1bca824 | 7528 | else |
c08435ec | 7529 | verbose(env, "%d: safe\n", env->insn_idx); |
f1bca824 AS |
7530 | } |
7531 | goto process_bpf_exit; | |
7532 | } | |
7533 | ||
c3494801 AS |
7534 | if (signal_pending(current)) |
7535 | return -EAGAIN; | |
7536 | ||
3c2ce60b DB |
7537 | if (need_resched()) |
7538 | cond_resched(); | |
7539 | ||
06ee7115 AS |
7540 | if (env->log.level & BPF_LOG_LEVEL2 || |
7541 | (env->log.level & BPF_LOG_LEVEL && do_print_state)) { | |
7542 | if (env->log.level & BPF_LOG_LEVEL2) | |
c08435ec | 7543 | verbose(env, "%d:", env->insn_idx); |
c5fc9692 | 7544 | else |
979d63d5 DB |
7545 | verbose(env, "\nfrom %d to %d%s:", |
7546 | env->prev_insn_idx, env->insn_idx, | |
7547 | env->cur_state->speculative ? | |
7548 | " (speculative execution)" : ""); | |
f4d7e40a | 7549 | print_verifier_state(env, state->frame[state->curframe]); |
17a52670 AS |
7550 | do_print_state = false; |
7551 | } | |
7552 | ||
06ee7115 | 7553 | if (env->log.level & BPF_LOG_LEVEL) { |
7105e828 DB |
7554 | const struct bpf_insn_cbs cbs = { |
7555 | .cb_print = verbose, | |
abe08840 | 7556 | .private_data = env, |
7105e828 DB |
7557 | }; |
7558 | ||
c08435ec DB |
7559 | verbose_linfo(env, env->insn_idx, "; "); |
7560 | verbose(env, "%d: ", env->insn_idx); | |
abe08840 | 7561 | print_bpf_insn(&cbs, insn, env->allow_ptr_leaks); |
17a52670 AS |
7562 | } |
7563 | ||
cae1927c | 7564 | if (bpf_prog_is_dev_bound(env->prog->aux)) { |
c08435ec DB |
7565 | err = bpf_prog_offload_verify_insn(env, env->insn_idx, |
7566 | env->prev_insn_idx); | |
cae1927c JK |
7567 | if (err) |
7568 | return err; | |
7569 | } | |
13a27dfc | 7570 | |
638f5b90 | 7571 | regs = cur_regs(env); |
c08435ec | 7572 | env->insn_aux_data[env->insn_idx].seen = true; |
b5dc0163 | 7573 | prev_insn_idx = env->insn_idx; |
fd978bf7 | 7574 | |
17a52670 | 7575 | if (class == BPF_ALU || class == BPF_ALU64) { |
1be7f75d | 7576 | err = check_alu_op(env, insn); |
17a52670 AS |
7577 | if (err) |
7578 | return err; | |
7579 | ||
7580 | } else if (class == BPF_LDX) { | |
3df126f3 | 7581 | enum bpf_reg_type *prev_src_type, src_reg_type; |
9bac3d6d AS |
7582 | |
7583 | /* check for reserved fields is already done */ | |
7584 | ||
17a52670 | 7585 | /* check src operand */ |
dc503a8a | 7586 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
7587 | if (err) |
7588 | return err; | |
7589 | ||
dc503a8a | 7590 | err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); |
17a52670 AS |
7591 | if (err) |
7592 | return err; | |
7593 | ||
725f9dcd AS |
7594 | src_reg_type = regs[insn->src_reg].type; |
7595 | ||
17a52670 AS |
7596 | /* check that memory (src_reg + off) is readable, |
7597 | * the state of dst_reg will be updated by this func | |
7598 | */ | |
c08435ec DB |
7599 | err = check_mem_access(env, env->insn_idx, insn->src_reg, |
7600 | insn->off, BPF_SIZE(insn->code), | |
7601 | BPF_READ, insn->dst_reg, false); | |
17a52670 AS |
7602 | if (err) |
7603 | return err; | |
7604 | ||
c08435ec | 7605 | prev_src_type = &env->insn_aux_data[env->insn_idx].ptr_type; |
3df126f3 JK |
7606 | |
7607 | if (*prev_src_type == NOT_INIT) { | |
9bac3d6d AS |
7608 | /* saw a valid insn |
7609 | * dst_reg = *(u32 *)(src_reg + off) | |
3df126f3 | 7610 | * save type to validate intersecting paths |
9bac3d6d | 7611 | */ |
3df126f3 | 7612 | *prev_src_type = src_reg_type; |
9bac3d6d | 7613 | |
c64b7983 | 7614 | } else if (reg_type_mismatch(src_reg_type, *prev_src_type)) { |
9bac3d6d AS |
7615 | /* ABuser program is trying to use the same insn |
7616 | * dst_reg = *(u32*) (src_reg + off) | |
7617 | * with different pointer types: | |
7618 | * src_reg == ctx in one branch and | |
7619 | * src_reg == stack|map in some other branch. | |
7620 | * Reject it. | |
7621 | */ | |
61bd5218 | 7622 | verbose(env, "same insn cannot be used with different pointers\n"); |
9bac3d6d AS |
7623 | return -EINVAL; |
7624 | } | |
7625 | ||
17a52670 | 7626 | } else if (class == BPF_STX) { |
3df126f3 | 7627 | enum bpf_reg_type *prev_dst_type, dst_reg_type; |
d691f9e8 | 7628 | |
17a52670 | 7629 | if (BPF_MODE(insn->code) == BPF_XADD) { |
c08435ec | 7630 | err = check_xadd(env, env->insn_idx, insn); |
17a52670 AS |
7631 | if (err) |
7632 | return err; | |
c08435ec | 7633 | env->insn_idx++; |
17a52670 AS |
7634 | continue; |
7635 | } | |
7636 | ||
17a52670 | 7637 | /* check src1 operand */ |
dc503a8a | 7638 | err = check_reg_arg(env, insn->src_reg, SRC_OP); |
17a52670 AS |
7639 | if (err) |
7640 | return err; | |
7641 | /* check src2 operand */ | |
dc503a8a | 7642 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
7643 | if (err) |
7644 | return err; | |
7645 | ||
d691f9e8 AS |
7646 | dst_reg_type = regs[insn->dst_reg].type; |
7647 | ||
17a52670 | 7648 | /* check that memory (dst_reg + off) is writeable */ |
c08435ec DB |
7649 | err = check_mem_access(env, env->insn_idx, insn->dst_reg, |
7650 | insn->off, BPF_SIZE(insn->code), | |
7651 | BPF_WRITE, insn->src_reg, false); | |
17a52670 AS |
7652 | if (err) |
7653 | return err; | |
7654 | ||
c08435ec | 7655 | prev_dst_type = &env->insn_aux_data[env->insn_idx].ptr_type; |
3df126f3 JK |
7656 | |
7657 | if (*prev_dst_type == NOT_INIT) { | |
7658 | *prev_dst_type = dst_reg_type; | |
c64b7983 | 7659 | } else if (reg_type_mismatch(dst_reg_type, *prev_dst_type)) { |
61bd5218 | 7660 | verbose(env, "same insn cannot be used with different pointers\n"); |
d691f9e8 AS |
7661 | return -EINVAL; |
7662 | } | |
7663 | ||
17a52670 AS |
7664 | } else if (class == BPF_ST) { |
7665 | if (BPF_MODE(insn->code) != BPF_MEM || | |
7666 | insn->src_reg != BPF_REG_0) { | |
61bd5218 | 7667 | verbose(env, "BPF_ST uses reserved fields\n"); |
17a52670 AS |
7668 | return -EINVAL; |
7669 | } | |
7670 | /* check src operand */ | |
dc503a8a | 7671 | err = check_reg_arg(env, insn->dst_reg, SRC_OP); |
17a52670 AS |
7672 | if (err) |
7673 | return err; | |
7674 | ||
f37a8cb8 | 7675 | if (is_ctx_reg(env, insn->dst_reg)) { |
9d2be44a | 7676 | verbose(env, "BPF_ST stores into R%d %s is not allowed\n", |
2a159c6f DB |
7677 | insn->dst_reg, |
7678 | reg_type_str[reg_state(env, insn->dst_reg)->type]); | |
f37a8cb8 DB |
7679 | return -EACCES; |
7680 | } | |
7681 | ||
17a52670 | 7682 | /* check that memory (dst_reg + off) is writeable */ |
c08435ec DB |
7683 | err = check_mem_access(env, env->insn_idx, insn->dst_reg, |
7684 | insn->off, BPF_SIZE(insn->code), | |
7685 | BPF_WRITE, -1, false); | |
17a52670 AS |
7686 | if (err) |
7687 | return err; | |
7688 | ||
092ed096 | 7689 | } else if (class == BPF_JMP || class == BPF_JMP32) { |
17a52670 AS |
7690 | u8 opcode = BPF_OP(insn->code); |
7691 | ||
2589726d | 7692 | env->jmps_processed++; |
17a52670 AS |
7693 | if (opcode == BPF_CALL) { |
7694 | if (BPF_SRC(insn->code) != BPF_K || | |
7695 | insn->off != 0 || | |
f4d7e40a AS |
7696 | (insn->src_reg != BPF_REG_0 && |
7697 | insn->src_reg != BPF_PSEUDO_CALL) || | |
092ed096 JW |
7698 | insn->dst_reg != BPF_REG_0 || |
7699 | class == BPF_JMP32) { | |
61bd5218 | 7700 | verbose(env, "BPF_CALL uses reserved fields\n"); |
17a52670 AS |
7701 | return -EINVAL; |
7702 | } | |
7703 | ||
d83525ca AS |
7704 | if (env->cur_state->active_spin_lock && |
7705 | (insn->src_reg == BPF_PSEUDO_CALL || | |
7706 | insn->imm != BPF_FUNC_spin_unlock)) { | |
7707 | verbose(env, "function calls are not allowed while holding a lock\n"); | |
7708 | return -EINVAL; | |
7709 | } | |
f4d7e40a | 7710 | if (insn->src_reg == BPF_PSEUDO_CALL) |
c08435ec | 7711 | err = check_func_call(env, insn, &env->insn_idx); |
f4d7e40a | 7712 | else |
c08435ec | 7713 | err = check_helper_call(env, insn->imm, env->insn_idx); |
17a52670 AS |
7714 | if (err) |
7715 | return err; | |
7716 | ||
7717 | } else if (opcode == BPF_JA) { | |
7718 | if (BPF_SRC(insn->code) != BPF_K || | |
7719 | insn->imm != 0 || | |
7720 | insn->src_reg != BPF_REG_0 || | |
092ed096 JW |
7721 | insn->dst_reg != BPF_REG_0 || |
7722 | class == BPF_JMP32) { | |
61bd5218 | 7723 | verbose(env, "BPF_JA uses reserved fields\n"); |
17a52670 AS |
7724 | return -EINVAL; |
7725 | } | |
7726 | ||
c08435ec | 7727 | env->insn_idx += insn->off + 1; |
17a52670 AS |
7728 | continue; |
7729 | ||
7730 | } else if (opcode == BPF_EXIT) { | |
7731 | if (BPF_SRC(insn->code) != BPF_K || | |
7732 | insn->imm != 0 || | |
7733 | insn->src_reg != BPF_REG_0 || | |
092ed096 JW |
7734 | insn->dst_reg != BPF_REG_0 || |
7735 | class == BPF_JMP32) { | |
61bd5218 | 7736 | verbose(env, "BPF_EXIT uses reserved fields\n"); |
17a52670 AS |
7737 | return -EINVAL; |
7738 | } | |
7739 | ||
d83525ca AS |
7740 | if (env->cur_state->active_spin_lock) { |
7741 | verbose(env, "bpf_spin_unlock is missing\n"); | |
7742 | return -EINVAL; | |
7743 | } | |
7744 | ||
f4d7e40a AS |
7745 | if (state->curframe) { |
7746 | /* exit from nested function */ | |
c08435ec | 7747 | err = prepare_func_exit(env, &env->insn_idx); |
f4d7e40a AS |
7748 | if (err) |
7749 | return err; | |
7750 | do_print_state = true; | |
7751 | continue; | |
7752 | } | |
7753 | ||
fd978bf7 JS |
7754 | err = check_reference_leak(env); |
7755 | if (err) | |
7756 | return err; | |
7757 | ||
17a52670 AS |
7758 | /* eBPF calling convetion is such that R0 is used |
7759 | * to return the value from eBPF program. | |
7760 | * Make sure that it's readable at this time | |
7761 | * of bpf_exit, which means that program wrote | |
7762 | * something into it earlier | |
7763 | */ | |
dc503a8a | 7764 | err = check_reg_arg(env, BPF_REG_0, SRC_OP); |
17a52670 AS |
7765 | if (err) |
7766 | return err; | |
7767 | ||
1be7f75d | 7768 | if (is_pointer_value(env, BPF_REG_0)) { |
61bd5218 | 7769 | verbose(env, "R0 leaks addr as return value\n"); |
1be7f75d AS |
7770 | return -EACCES; |
7771 | } | |
7772 | ||
390ee7e2 AS |
7773 | err = check_return_code(env); |
7774 | if (err) | |
7775 | return err; | |
f1bca824 | 7776 | process_bpf_exit: |
2589726d | 7777 | update_branch_counts(env, env->cur_state); |
b5dc0163 | 7778 | err = pop_stack(env, &prev_insn_idx, |
c08435ec | 7779 | &env->insn_idx); |
638f5b90 AS |
7780 | if (err < 0) { |
7781 | if (err != -ENOENT) | |
7782 | return err; | |
17a52670 AS |
7783 | break; |
7784 | } else { | |
7785 | do_print_state = true; | |
7786 | continue; | |
7787 | } | |
7788 | } else { | |
c08435ec | 7789 | err = check_cond_jmp_op(env, insn, &env->insn_idx); |
17a52670 AS |
7790 | if (err) |
7791 | return err; | |
7792 | } | |
7793 | } else if (class == BPF_LD) { | |
7794 | u8 mode = BPF_MODE(insn->code); | |
7795 | ||
7796 | if (mode == BPF_ABS || mode == BPF_IND) { | |
ddd872bc AS |
7797 | err = check_ld_abs(env, insn); |
7798 | if (err) | |
7799 | return err; | |
7800 | ||
17a52670 AS |
7801 | } else if (mode == BPF_IMM) { |
7802 | err = check_ld_imm(env, insn); | |
7803 | if (err) | |
7804 | return err; | |
7805 | ||
c08435ec DB |
7806 | env->insn_idx++; |
7807 | env->insn_aux_data[env->insn_idx].seen = true; | |
17a52670 | 7808 | } else { |
61bd5218 | 7809 | verbose(env, "invalid BPF_LD mode\n"); |
17a52670 AS |
7810 | return -EINVAL; |
7811 | } | |
7812 | } else { | |
61bd5218 | 7813 | verbose(env, "unknown insn class %d\n", class); |
17a52670 AS |
7814 | return -EINVAL; |
7815 | } | |
7816 | ||
c08435ec | 7817 | env->insn_idx++; |
17a52670 AS |
7818 | } |
7819 | ||
9c8105bd | 7820 | env->prog->aux->stack_depth = env->subprog_info[0].stack_depth; |
17a52670 AS |
7821 | return 0; |
7822 | } | |
7823 | ||
56f668df MKL |
7824 | static int check_map_prealloc(struct bpf_map *map) |
7825 | { | |
7826 | return (map->map_type != BPF_MAP_TYPE_HASH && | |
bcc6b1b7 MKL |
7827 | map->map_type != BPF_MAP_TYPE_PERCPU_HASH && |
7828 | map->map_type != BPF_MAP_TYPE_HASH_OF_MAPS) || | |
56f668df MKL |
7829 | !(map->map_flags & BPF_F_NO_PREALLOC); |
7830 | } | |
7831 | ||
d83525ca AS |
7832 | static bool is_tracing_prog_type(enum bpf_prog_type type) |
7833 | { | |
7834 | switch (type) { | |
7835 | case BPF_PROG_TYPE_KPROBE: | |
7836 | case BPF_PROG_TYPE_TRACEPOINT: | |
7837 | case BPF_PROG_TYPE_PERF_EVENT: | |
7838 | case BPF_PROG_TYPE_RAW_TRACEPOINT: | |
7839 | return true; | |
7840 | default: | |
7841 | return false; | |
7842 | } | |
7843 | } | |
7844 | ||
61bd5218 JK |
7845 | static int check_map_prog_compatibility(struct bpf_verifier_env *env, |
7846 | struct bpf_map *map, | |
fdc15d38 AS |
7847 | struct bpf_prog *prog) |
7848 | ||
7849 | { | |
56f668df MKL |
7850 | /* Make sure that BPF_PROG_TYPE_PERF_EVENT programs only use |
7851 | * preallocated hash maps, since doing memory allocation | |
7852 | * in overflow_handler can crash depending on where nmi got | |
7853 | * triggered. | |
7854 | */ | |
7855 | if (prog->type == BPF_PROG_TYPE_PERF_EVENT) { | |
7856 | if (!check_map_prealloc(map)) { | |
61bd5218 | 7857 | verbose(env, "perf_event programs can only use preallocated hash map\n"); |
56f668df MKL |
7858 | return -EINVAL; |
7859 | } | |
7860 | if (map->inner_map_meta && | |
7861 | !check_map_prealloc(map->inner_map_meta)) { | |
61bd5218 | 7862 | verbose(env, "perf_event programs can only use preallocated inner hash map\n"); |
56f668df MKL |
7863 | return -EINVAL; |
7864 | } | |
fdc15d38 | 7865 | } |
a3884572 | 7866 | |
d83525ca AS |
7867 | if ((is_tracing_prog_type(prog->type) || |
7868 | prog->type == BPF_PROG_TYPE_SOCKET_FILTER) && | |
7869 | map_value_has_spin_lock(map)) { | |
7870 | verbose(env, "tracing progs cannot use bpf_spin_lock yet\n"); | |
7871 | return -EINVAL; | |
7872 | } | |
7873 | ||
a3884572 | 7874 | if ((bpf_prog_is_dev_bound(prog->aux) || bpf_map_is_dev_bound(map)) && |
09728266 | 7875 | !bpf_offload_prog_map_match(prog, map)) { |
a3884572 JK |
7876 | verbose(env, "offload device mismatch between prog and map\n"); |
7877 | return -EINVAL; | |
7878 | } | |
7879 | ||
fdc15d38 AS |
7880 | return 0; |
7881 | } | |
7882 | ||
b741f163 RG |
7883 | static bool bpf_map_is_cgroup_storage(struct bpf_map *map) |
7884 | { | |
7885 | return (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE || | |
7886 | map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE); | |
7887 | } | |
7888 | ||
0246e64d AS |
7889 | /* look for pseudo eBPF instructions that access map FDs and |
7890 | * replace them with actual map pointers | |
7891 | */ | |
58e2af8b | 7892 | static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env) |
0246e64d AS |
7893 | { |
7894 | struct bpf_insn *insn = env->prog->insnsi; | |
7895 | int insn_cnt = env->prog->len; | |
fdc15d38 | 7896 | int i, j, err; |
0246e64d | 7897 | |
f1f7714e | 7898 | err = bpf_prog_calc_tag(env->prog); |
aafe6ae9 DB |
7899 | if (err) |
7900 | return err; | |
7901 | ||
0246e64d | 7902 | for (i = 0; i < insn_cnt; i++, insn++) { |
9bac3d6d | 7903 | if (BPF_CLASS(insn->code) == BPF_LDX && |
d691f9e8 | 7904 | (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0)) { |
61bd5218 | 7905 | verbose(env, "BPF_LDX uses reserved fields\n"); |
9bac3d6d AS |
7906 | return -EINVAL; |
7907 | } | |
7908 | ||
d691f9e8 AS |
7909 | if (BPF_CLASS(insn->code) == BPF_STX && |
7910 | ((BPF_MODE(insn->code) != BPF_MEM && | |
7911 | BPF_MODE(insn->code) != BPF_XADD) || insn->imm != 0)) { | |
61bd5218 | 7912 | verbose(env, "BPF_STX uses reserved fields\n"); |
d691f9e8 AS |
7913 | return -EINVAL; |
7914 | } | |
7915 | ||
0246e64d | 7916 | if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) { |
d8eca5bb | 7917 | struct bpf_insn_aux_data *aux; |
0246e64d AS |
7918 | struct bpf_map *map; |
7919 | struct fd f; | |
d8eca5bb | 7920 | u64 addr; |
0246e64d AS |
7921 | |
7922 | if (i == insn_cnt - 1 || insn[1].code != 0 || | |
7923 | insn[1].dst_reg != 0 || insn[1].src_reg != 0 || | |
7924 | insn[1].off != 0) { | |
61bd5218 | 7925 | verbose(env, "invalid bpf_ld_imm64 insn\n"); |
0246e64d AS |
7926 | return -EINVAL; |
7927 | } | |
7928 | ||
d8eca5bb | 7929 | if (insn[0].src_reg == 0) |
0246e64d AS |
7930 | /* valid generic load 64-bit imm */ |
7931 | goto next_insn; | |
7932 | ||
d8eca5bb DB |
7933 | /* In final convert_pseudo_ld_imm64() step, this is |
7934 | * converted into regular 64-bit imm load insn. | |
7935 | */ | |
7936 | if ((insn[0].src_reg != BPF_PSEUDO_MAP_FD && | |
7937 | insn[0].src_reg != BPF_PSEUDO_MAP_VALUE) || | |
7938 | (insn[0].src_reg == BPF_PSEUDO_MAP_FD && | |
7939 | insn[1].imm != 0)) { | |
7940 | verbose(env, | |
7941 | "unrecognized bpf_ld_imm64 insn\n"); | |
0246e64d AS |
7942 | return -EINVAL; |
7943 | } | |
7944 | ||
20182390 | 7945 | f = fdget(insn[0].imm); |
c2101297 | 7946 | map = __bpf_map_get(f); |
0246e64d | 7947 | if (IS_ERR(map)) { |
61bd5218 | 7948 | verbose(env, "fd %d is not pointing to valid bpf_map\n", |
20182390 | 7949 | insn[0].imm); |
0246e64d AS |
7950 | return PTR_ERR(map); |
7951 | } | |
7952 | ||
61bd5218 | 7953 | err = check_map_prog_compatibility(env, map, env->prog); |
fdc15d38 AS |
7954 | if (err) { |
7955 | fdput(f); | |
7956 | return err; | |
7957 | } | |
7958 | ||
d8eca5bb DB |
7959 | aux = &env->insn_aux_data[i]; |
7960 | if (insn->src_reg == BPF_PSEUDO_MAP_FD) { | |
7961 | addr = (unsigned long)map; | |
7962 | } else { | |
7963 | u32 off = insn[1].imm; | |
7964 | ||
7965 | if (off >= BPF_MAX_VAR_OFF) { | |
7966 | verbose(env, "direct value offset of %u is not allowed\n", off); | |
7967 | fdput(f); | |
7968 | return -EINVAL; | |
7969 | } | |
7970 | ||
7971 | if (!map->ops->map_direct_value_addr) { | |
7972 | verbose(env, "no direct value access support for this map type\n"); | |
7973 | fdput(f); | |
7974 | return -EINVAL; | |
7975 | } | |
7976 | ||
7977 | err = map->ops->map_direct_value_addr(map, &addr, off); | |
7978 | if (err) { | |
7979 | verbose(env, "invalid access to map value pointer, value_size=%u off=%u\n", | |
7980 | map->value_size, off); | |
7981 | fdput(f); | |
7982 | return err; | |
7983 | } | |
7984 | ||
7985 | aux->map_off = off; | |
7986 | addr += off; | |
7987 | } | |
7988 | ||
7989 | insn[0].imm = (u32)addr; | |
7990 | insn[1].imm = addr >> 32; | |
0246e64d AS |
7991 | |
7992 | /* check whether we recorded this map already */ | |
d8eca5bb | 7993 | for (j = 0; j < env->used_map_cnt; j++) { |
0246e64d | 7994 | if (env->used_maps[j] == map) { |
d8eca5bb | 7995 | aux->map_index = j; |
0246e64d AS |
7996 | fdput(f); |
7997 | goto next_insn; | |
7998 | } | |
d8eca5bb | 7999 | } |
0246e64d AS |
8000 | |
8001 | if (env->used_map_cnt >= MAX_USED_MAPS) { | |
8002 | fdput(f); | |
8003 | return -E2BIG; | |
8004 | } | |
8005 | ||
0246e64d AS |
8006 | /* hold the map. If the program is rejected by verifier, |
8007 | * the map will be released by release_maps() or it | |
8008 | * will be used by the valid program until it's unloaded | |
ab7f5bf0 | 8009 | * and all maps are released in free_used_maps() |
0246e64d | 8010 | */ |
92117d84 AS |
8011 | map = bpf_map_inc(map, false); |
8012 | if (IS_ERR(map)) { | |
8013 | fdput(f); | |
8014 | return PTR_ERR(map); | |
8015 | } | |
d8eca5bb DB |
8016 | |
8017 | aux->map_index = env->used_map_cnt; | |
92117d84 AS |
8018 | env->used_maps[env->used_map_cnt++] = map; |
8019 | ||
b741f163 | 8020 | if (bpf_map_is_cgroup_storage(map) && |
de9cbbaa | 8021 | bpf_cgroup_storage_assign(env->prog, map)) { |
b741f163 | 8022 | verbose(env, "only one cgroup storage of each type is allowed\n"); |
de9cbbaa RG |
8023 | fdput(f); |
8024 | return -EBUSY; | |
8025 | } | |
8026 | ||
0246e64d AS |
8027 | fdput(f); |
8028 | next_insn: | |
8029 | insn++; | |
8030 | i++; | |
5e581dad DB |
8031 | continue; |
8032 | } | |
8033 | ||
8034 | /* Basic sanity check before we invest more work here. */ | |
8035 | if (!bpf_opcode_in_insntable(insn->code)) { | |
8036 | verbose(env, "unknown opcode %02x\n", insn->code); | |
8037 | return -EINVAL; | |
0246e64d AS |
8038 | } |
8039 | } | |
8040 | ||
8041 | /* now all pseudo BPF_LD_IMM64 instructions load valid | |
8042 | * 'struct bpf_map *' into a register instead of user map_fd. | |
8043 | * These pointers will be used later by verifier to validate map access. | |
8044 | */ | |
8045 | return 0; | |
8046 | } | |
8047 | ||
8048 | /* drop refcnt of maps used by the rejected program */ | |
58e2af8b | 8049 | static void release_maps(struct bpf_verifier_env *env) |
0246e64d | 8050 | { |
8bad74f9 | 8051 | enum bpf_cgroup_storage_type stype; |
0246e64d AS |
8052 | int i; |
8053 | ||
8bad74f9 RG |
8054 | for_each_cgroup_storage_type(stype) { |
8055 | if (!env->prog->aux->cgroup_storage[stype]) | |
8056 | continue; | |
de9cbbaa | 8057 | bpf_cgroup_storage_release(env->prog, |
8bad74f9 RG |
8058 | env->prog->aux->cgroup_storage[stype]); |
8059 | } | |
de9cbbaa | 8060 | |
0246e64d AS |
8061 | for (i = 0; i < env->used_map_cnt; i++) |
8062 | bpf_map_put(env->used_maps[i]); | |
8063 | } | |
8064 | ||
8065 | /* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */ | |
58e2af8b | 8066 | static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env) |
0246e64d AS |
8067 | { |
8068 | struct bpf_insn *insn = env->prog->insnsi; | |
8069 | int insn_cnt = env->prog->len; | |
8070 | int i; | |
8071 | ||
8072 | for (i = 0; i < insn_cnt; i++, insn++) | |
8073 | if (insn->code == (BPF_LD | BPF_IMM | BPF_DW)) | |
8074 | insn->src_reg = 0; | |
8075 | } | |
8076 | ||
8041902d AS |
8077 | /* single env->prog->insni[off] instruction was replaced with the range |
8078 | * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying | |
8079 | * [0, off) and [off, end) to new locations, so the patched range stays zero | |
8080 | */ | |
b325fbca JW |
8081 | static int adjust_insn_aux_data(struct bpf_verifier_env *env, |
8082 | struct bpf_prog *new_prog, u32 off, u32 cnt) | |
8041902d AS |
8083 | { |
8084 | struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data; | |
b325fbca JW |
8085 | struct bpf_insn *insn = new_prog->insnsi; |
8086 | u32 prog_len; | |
c131187d | 8087 | int i; |
8041902d | 8088 | |
b325fbca JW |
8089 | /* aux info at OFF always needs adjustment, no matter fast path |
8090 | * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the | |
8091 | * original insn at old prog. | |
8092 | */ | |
8093 | old_data[off].zext_dst = insn_has_def32(env, insn + off + cnt - 1); | |
8094 | ||
8041902d AS |
8095 | if (cnt == 1) |
8096 | return 0; | |
b325fbca | 8097 | prog_len = new_prog->len; |
fad953ce KC |
8098 | new_data = vzalloc(array_size(prog_len, |
8099 | sizeof(struct bpf_insn_aux_data))); | |
8041902d AS |
8100 | if (!new_data) |
8101 | return -ENOMEM; | |
8102 | memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off); | |
8103 | memcpy(new_data + off + cnt - 1, old_data + off, | |
8104 | sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1)); | |
b325fbca | 8105 | for (i = off; i < off + cnt - 1; i++) { |
c131187d | 8106 | new_data[i].seen = true; |
b325fbca JW |
8107 | new_data[i].zext_dst = insn_has_def32(env, insn + i); |
8108 | } | |
8041902d AS |
8109 | env->insn_aux_data = new_data; |
8110 | vfree(old_data); | |
8111 | return 0; | |
8112 | } | |
8113 | ||
cc8b0b92 AS |
8114 | static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len) |
8115 | { | |
8116 | int i; | |
8117 | ||
8118 | if (len == 1) | |
8119 | return; | |
4cb3d99c JW |
8120 | /* NOTE: fake 'exit' subprog should be updated as well. */ |
8121 | for (i = 0; i <= env->subprog_cnt; i++) { | |
afd59424 | 8122 | if (env->subprog_info[i].start <= off) |
cc8b0b92 | 8123 | continue; |
9c8105bd | 8124 | env->subprog_info[i].start += len - 1; |
cc8b0b92 AS |
8125 | } |
8126 | } | |
8127 | ||
8041902d AS |
8128 | static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off, |
8129 | const struct bpf_insn *patch, u32 len) | |
8130 | { | |
8131 | struct bpf_prog *new_prog; | |
8132 | ||
8133 | new_prog = bpf_patch_insn_single(env->prog, off, patch, len); | |
4f73379e AS |
8134 | if (IS_ERR(new_prog)) { |
8135 | if (PTR_ERR(new_prog) == -ERANGE) | |
8136 | verbose(env, | |
8137 | "insn %d cannot be patched due to 16-bit range\n", | |
8138 | env->insn_aux_data[off].orig_idx); | |
8041902d | 8139 | return NULL; |
4f73379e | 8140 | } |
b325fbca | 8141 | if (adjust_insn_aux_data(env, new_prog, off, len)) |
8041902d | 8142 | return NULL; |
cc8b0b92 | 8143 | adjust_subprog_starts(env, off, len); |
8041902d AS |
8144 | return new_prog; |
8145 | } | |
8146 | ||
52875a04 JK |
8147 | static int adjust_subprog_starts_after_remove(struct bpf_verifier_env *env, |
8148 | u32 off, u32 cnt) | |
8149 | { | |
8150 | int i, j; | |
8151 | ||
8152 | /* find first prog starting at or after off (first to remove) */ | |
8153 | for (i = 0; i < env->subprog_cnt; i++) | |
8154 | if (env->subprog_info[i].start >= off) | |
8155 | break; | |
8156 | /* find first prog starting at or after off + cnt (first to stay) */ | |
8157 | for (j = i; j < env->subprog_cnt; j++) | |
8158 | if (env->subprog_info[j].start >= off + cnt) | |
8159 | break; | |
8160 | /* if j doesn't start exactly at off + cnt, we are just removing | |
8161 | * the front of previous prog | |
8162 | */ | |
8163 | if (env->subprog_info[j].start != off + cnt) | |
8164 | j--; | |
8165 | ||
8166 | if (j > i) { | |
8167 | struct bpf_prog_aux *aux = env->prog->aux; | |
8168 | int move; | |
8169 | ||
8170 | /* move fake 'exit' subprog as well */ | |
8171 | move = env->subprog_cnt + 1 - j; | |
8172 | ||
8173 | memmove(env->subprog_info + i, | |
8174 | env->subprog_info + j, | |
8175 | sizeof(*env->subprog_info) * move); | |
8176 | env->subprog_cnt -= j - i; | |
8177 | ||
8178 | /* remove func_info */ | |
8179 | if (aux->func_info) { | |
8180 | move = aux->func_info_cnt - j; | |
8181 | ||
8182 | memmove(aux->func_info + i, | |
8183 | aux->func_info + j, | |
8184 | sizeof(*aux->func_info) * move); | |
8185 | aux->func_info_cnt -= j - i; | |
8186 | /* func_info->insn_off is set after all code rewrites, | |
8187 | * in adjust_btf_func() - no need to adjust | |
8188 | */ | |
8189 | } | |
8190 | } else { | |
8191 | /* convert i from "first prog to remove" to "first to adjust" */ | |
8192 | if (env->subprog_info[i].start == off) | |
8193 | i++; | |
8194 | } | |
8195 | ||
8196 | /* update fake 'exit' subprog as well */ | |
8197 | for (; i <= env->subprog_cnt; i++) | |
8198 | env->subprog_info[i].start -= cnt; | |
8199 | ||
8200 | return 0; | |
8201 | } | |
8202 | ||
8203 | static int bpf_adj_linfo_after_remove(struct bpf_verifier_env *env, u32 off, | |
8204 | u32 cnt) | |
8205 | { | |
8206 | struct bpf_prog *prog = env->prog; | |
8207 | u32 i, l_off, l_cnt, nr_linfo; | |
8208 | struct bpf_line_info *linfo; | |
8209 | ||
8210 | nr_linfo = prog->aux->nr_linfo; | |
8211 | if (!nr_linfo) | |
8212 | return 0; | |
8213 | ||
8214 | linfo = prog->aux->linfo; | |
8215 | ||
8216 | /* find first line info to remove, count lines to be removed */ | |
8217 | for (i = 0; i < nr_linfo; i++) | |
8218 | if (linfo[i].insn_off >= off) | |
8219 | break; | |
8220 | ||
8221 | l_off = i; | |
8222 | l_cnt = 0; | |
8223 | for (; i < nr_linfo; i++) | |
8224 | if (linfo[i].insn_off < off + cnt) | |
8225 | l_cnt++; | |
8226 | else | |
8227 | break; | |
8228 | ||
8229 | /* First live insn doesn't match first live linfo, it needs to "inherit" | |
8230 | * last removed linfo. prog is already modified, so prog->len == off | |
8231 | * means no live instructions after (tail of the program was removed). | |
8232 | */ | |
8233 | if (prog->len != off && l_cnt && | |
8234 | (i == nr_linfo || linfo[i].insn_off != off + cnt)) { | |
8235 | l_cnt--; | |
8236 | linfo[--i].insn_off = off + cnt; | |
8237 | } | |
8238 | ||
8239 | /* remove the line info which refer to the removed instructions */ | |
8240 | if (l_cnt) { | |
8241 | memmove(linfo + l_off, linfo + i, | |
8242 | sizeof(*linfo) * (nr_linfo - i)); | |
8243 | ||
8244 | prog->aux->nr_linfo -= l_cnt; | |
8245 | nr_linfo = prog->aux->nr_linfo; | |
8246 | } | |
8247 | ||
8248 | /* pull all linfo[i].insn_off >= off + cnt in by cnt */ | |
8249 | for (i = l_off; i < nr_linfo; i++) | |
8250 | linfo[i].insn_off -= cnt; | |
8251 | ||
8252 | /* fix up all subprogs (incl. 'exit') which start >= off */ | |
8253 | for (i = 0; i <= env->subprog_cnt; i++) | |
8254 | if (env->subprog_info[i].linfo_idx > l_off) { | |
8255 | /* program may have started in the removed region but | |
8256 | * may not be fully removed | |
8257 | */ | |
8258 | if (env->subprog_info[i].linfo_idx >= l_off + l_cnt) | |
8259 | env->subprog_info[i].linfo_idx -= l_cnt; | |
8260 | else | |
8261 | env->subprog_info[i].linfo_idx = l_off; | |
8262 | } | |
8263 | ||
8264 | return 0; | |
8265 | } | |
8266 | ||
8267 | static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt) | |
8268 | { | |
8269 | struct bpf_insn_aux_data *aux_data = env->insn_aux_data; | |
8270 | unsigned int orig_prog_len = env->prog->len; | |
8271 | int err; | |
8272 | ||
08ca90af JK |
8273 | if (bpf_prog_is_dev_bound(env->prog->aux)) |
8274 | bpf_prog_offload_remove_insns(env, off, cnt); | |
8275 | ||
52875a04 JK |
8276 | err = bpf_remove_insns(env->prog, off, cnt); |
8277 | if (err) | |
8278 | return err; | |
8279 | ||
8280 | err = adjust_subprog_starts_after_remove(env, off, cnt); | |
8281 | if (err) | |
8282 | return err; | |
8283 | ||
8284 | err = bpf_adj_linfo_after_remove(env, off, cnt); | |
8285 | if (err) | |
8286 | return err; | |
8287 | ||
8288 | memmove(aux_data + off, aux_data + off + cnt, | |
8289 | sizeof(*aux_data) * (orig_prog_len - off - cnt)); | |
8290 | ||
8291 | return 0; | |
8292 | } | |
8293 | ||
2a5418a1 DB |
8294 | /* The verifier does more data flow analysis than llvm and will not |
8295 | * explore branches that are dead at run time. Malicious programs can | |
8296 | * have dead code too. Therefore replace all dead at-run-time code | |
8297 | * with 'ja -1'. | |
8298 | * | |
8299 | * Just nops are not optimal, e.g. if they would sit at the end of the | |
8300 | * program and through another bug we would manage to jump there, then | |
8301 | * we'd execute beyond program memory otherwise. Returning exception | |
8302 | * code also wouldn't work since we can have subprogs where the dead | |
8303 | * code could be located. | |
c131187d AS |
8304 | */ |
8305 | static void sanitize_dead_code(struct bpf_verifier_env *env) | |
8306 | { | |
8307 | struct bpf_insn_aux_data *aux_data = env->insn_aux_data; | |
2a5418a1 | 8308 | struct bpf_insn trap = BPF_JMP_IMM(BPF_JA, 0, 0, -1); |
c131187d AS |
8309 | struct bpf_insn *insn = env->prog->insnsi; |
8310 | const int insn_cnt = env->prog->len; | |
8311 | int i; | |
8312 | ||
8313 | for (i = 0; i < insn_cnt; i++) { | |
8314 | if (aux_data[i].seen) | |
8315 | continue; | |
2a5418a1 | 8316 | memcpy(insn + i, &trap, sizeof(trap)); |
c131187d AS |
8317 | } |
8318 | } | |
8319 | ||
e2ae4ca2 JK |
8320 | static bool insn_is_cond_jump(u8 code) |
8321 | { | |
8322 | u8 op; | |
8323 | ||
092ed096 JW |
8324 | if (BPF_CLASS(code) == BPF_JMP32) |
8325 | return true; | |
8326 | ||
e2ae4ca2 JK |
8327 | if (BPF_CLASS(code) != BPF_JMP) |
8328 | return false; | |
8329 | ||
8330 | op = BPF_OP(code); | |
8331 | return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL; | |
8332 | } | |
8333 | ||
8334 | static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env) | |
8335 | { | |
8336 | struct bpf_insn_aux_data *aux_data = env->insn_aux_data; | |
8337 | struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0); | |
8338 | struct bpf_insn *insn = env->prog->insnsi; | |
8339 | const int insn_cnt = env->prog->len; | |
8340 | int i; | |
8341 | ||
8342 | for (i = 0; i < insn_cnt; i++, insn++) { | |
8343 | if (!insn_is_cond_jump(insn->code)) | |
8344 | continue; | |
8345 | ||
8346 | if (!aux_data[i + 1].seen) | |
8347 | ja.off = insn->off; | |
8348 | else if (!aux_data[i + 1 + insn->off].seen) | |
8349 | ja.off = 0; | |
8350 | else | |
8351 | continue; | |
8352 | ||
08ca90af JK |
8353 | if (bpf_prog_is_dev_bound(env->prog->aux)) |
8354 | bpf_prog_offload_replace_insn(env, i, &ja); | |
8355 | ||
e2ae4ca2 JK |
8356 | memcpy(insn, &ja, sizeof(ja)); |
8357 | } | |
8358 | } | |
8359 | ||
52875a04 JK |
8360 | static int opt_remove_dead_code(struct bpf_verifier_env *env) |
8361 | { | |
8362 | struct bpf_insn_aux_data *aux_data = env->insn_aux_data; | |
8363 | int insn_cnt = env->prog->len; | |
8364 | int i, err; | |
8365 | ||
8366 | for (i = 0; i < insn_cnt; i++) { | |
8367 | int j; | |
8368 | ||
8369 | j = 0; | |
8370 | while (i + j < insn_cnt && !aux_data[i + j].seen) | |
8371 | j++; | |
8372 | if (!j) | |
8373 | continue; | |
8374 | ||
8375 | err = verifier_remove_insns(env, i, j); | |
8376 | if (err) | |
8377 | return err; | |
8378 | insn_cnt = env->prog->len; | |
8379 | } | |
8380 | ||
8381 | return 0; | |
8382 | } | |
8383 | ||
a1b14abc JK |
8384 | static int opt_remove_nops(struct bpf_verifier_env *env) |
8385 | { | |
8386 | const struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0); | |
8387 | struct bpf_insn *insn = env->prog->insnsi; | |
8388 | int insn_cnt = env->prog->len; | |
8389 | int i, err; | |
8390 | ||
8391 | for (i = 0; i < insn_cnt; i++) { | |
8392 | if (memcmp(&insn[i], &ja, sizeof(ja))) | |
8393 | continue; | |
8394 | ||
8395 | err = verifier_remove_insns(env, i, 1); | |
8396 | if (err) | |
8397 | return err; | |
8398 | insn_cnt--; | |
8399 | i--; | |
8400 | } | |
8401 | ||
8402 | return 0; | |
8403 | } | |
8404 | ||
d6c2308c JW |
8405 | static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env, |
8406 | const union bpf_attr *attr) | |
a4b1d3c1 | 8407 | { |
d6c2308c | 8408 | struct bpf_insn *patch, zext_patch[2], rnd_hi32_patch[4]; |
a4b1d3c1 | 8409 | struct bpf_insn_aux_data *aux = env->insn_aux_data; |
d6c2308c | 8410 | int i, patch_len, delta = 0, len = env->prog->len; |
a4b1d3c1 | 8411 | struct bpf_insn *insns = env->prog->insnsi; |
a4b1d3c1 | 8412 | struct bpf_prog *new_prog; |
d6c2308c | 8413 | bool rnd_hi32; |
a4b1d3c1 | 8414 | |
d6c2308c | 8415 | rnd_hi32 = attr->prog_flags & BPF_F_TEST_RND_HI32; |
a4b1d3c1 | 8416 | zext_patch[1] = BPF_ZEXT_REG(0); |
d6c2308c JW |
8417 | rnd_hi32_patch[1] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, 0); |
8418 | rnd_hi32_patch[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); | |
8419 | rnd_hi32_patch[3] = BPF_ALU64_REG(BPF_OR, 0, BPF_REG_AX); | |
a4b1d3c1 JW |
8420 | for (i = 0; i < len; i++) { |
8421 | int adj_idx = i + delta; | |
8422 | struct bpf_insn insn; | |
8423 | ||
d6c2308c JW |
8424 | insn = insns[adj_idx]; |
8425 | if (!aux[adj_idx].zext_dst) { | |
8426 | u8 code, class; | |
8427 | u32 imm_rnd; | |
8428 | ||
8429 | if (!rnd_hi32) | |
8430 | continue; | |
8431 | ||
8432 | code = insn.code; | |
8433 | class = BPF_CLASS(code); | |
8434 | if (insn_no_def(&insn)) | |
8435 | continue; | |
8436 | ||
8437 | /* NOTE: arg "reg" (the fourth one) is only used for | |
8438 | * BPF_STX which has been ruled out in above | |
8439 | * check, it is safe to pass NULL here. | |
8440 | */ | |
8441 | if (is_reg64(env, &insn, insn.dst_reg, NULL, DST_OP)) { | |
8442 | if (class == BPF_LD && | |
8443 | BPF_MODE(code) == BPF_IMM) | |
8444 | i++; | |
8445 | continue; | |
8446 | } | |
8447 | ||
8448 | /* ctx load could be transformed into wider load. */ | |
8449 | if (class == BPF_LDX && | |
8450 | aux[adj_idx].ptr_type == PTR_TO_CTX) | |
8451 | continue; | |
8452 | ||
8453 | imm_rnd = get_random_int(); | |
8454 | rnd_hi32_patch[0] = insn; | |
8455 | rnd_hi32_patch[1].imm = imm_rnd; | |
8456 | rnd_hi32_patch[3].dst_reg = insn.dst_reg; | |
8457 | patch = rnd_hi32_patch; | |
8458 | patch_len = 4; | |
8459 | goto apply_patch_buffer; | |
8460 | } | |
8461 | ||
8462 | if (!bpf_jit_needs_zext()) | |
a4b1d3c1 JW |
8463 | continue; |
8464 | ||
a4b1d3c1 JW |
8465 | zext_patch[0] = insn; |
8466 | zext_patch[1].dst_reg = insn.dst_reg; | |
8467 | zext_patch[1].src_reg = insn.dst_reg; | |
d6c2308c JW |
8468 | patch = zext_patch; |
8469 | patch_len = 2; | |
8470 | apply_patch_buffer: | |
8471 | new_prog = bpf_patch_insn_data(env, adj_idx, patch, patch_len); | |
a4b1d3c1 JW |
8472 | if (!new_prog) |
8473 | return -ENOMEM; | |
8474 | env->prog = new_prog; | |
8475 | insns = new_prog->insnsi; | |
8476 | aux = env->insn_aux_data; | |
d6c2308c | 8477 | delta += patch_len - 1; |
a4b1d3c1 JW |
8478 | } |
8479 | ||
8480 | return 0; | |
8481 | } | |
8482 | ||
c64b7983 JS |
8483 | /* convert load instructions that access fields of a context type into a |
8484 | * sequence of instructions that access fields of the underlying structure: | |
8485 | * struct __sk_buff -> struct sk_buff | |
8486 | * struct bpf_sock_ops -> struct sock | |
9bac3d6d | 8487 | */ |
58e2af8b | 8488 | static int convert_ctx_accesses(struct bpf_verifier_env *env) |
9bac3d6d | 8489 | { |
00176a34 | 8490 | const struct bpf_verifier_ops *ops = env->ops; |
f96da094 | 8491 | int i, cnt, size, ctx_field_size, delta = 0; |
3df126f3 | 8492 | const int insn_cnt = env->prog->len; |
36bbef52 | 8493 | struct bpf_insn insn_buf[16], *insn; |
46f53a65 | 8494 | u32 target_size, size_default, off; |
9bac3d6d | 8495 | struct bpf_prog *new_prog; |
d691f9e8 | 8496 | enum bpf_access_type type; |
f96da094 | 8497 | bool is_narrower_load; |
9bac3d6d | 8498 | |
b09928b9 DB |
8499 | if (ops->gen_prologue || env->seen_direct_write) { |
8500 | if (!ops->gen_prologue) { | |
8501 | verbose(env, "bpf verifier is misconfigured\n"); | |
8502 | return -EINVAL; | |
8503 | } | |
36bbef52 DB |
8504 | cnt = ops->gen_prologue(insn_buf, env->seen_direct_write, |
8505 | env->prog); | |
8506 | if (cnt >= ARRAY_SIZE(insn_buf)) { | |
61bd5218 | 8507 | verbose(env, "bpf verifier is misconfigured\n"); |
36bbef52 DB |
8508 | return -EINVAL; |
8509 | } else if (cnt) { | |
8041902d | 8510 | new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt); |
36bbef52 DB |
8511 | if (!new_prog) |
8512 | return -ENOMEM; | |
8041902d | 8513 | |
36bbef52 | 8514 | env->prog = new_prog; |
3df126f3 | 8515 | delta += cnt - 1; |
36bbef52 DB |
8516 | } |
8517 | } | |
8518 | ||
c64b7983 | 8519 | if (bpf_prog_is_dev_bound(env->prog->aux)) |
9bac3d6d AS |
8520 | return 0; |
8521 | ||
3df126f3 | 8522 | insn = env->prog->insnsi + delta; |
36bbef52 | 8523 | |
9bac3d6d | 8524 | for (i = 0; i < insn_cnt; i++, insn++) { |
c64b7983 JS |
8525 | bpf_convert_ctx_access_t convert_ctx_access; |
8526 | ||
62c7989b DB |
8527 | if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) || |
8528 | insn->code == (BPF_LDX | BPF_MEM | BPF_H) || | |
8529 | insn->code == (BPF_LDX | BPF_MEM | BPF_W) || | |
ea2e7ce5 | 8530 | insn->code == (BPF_LDX | BPF_MEM | BPF_DW)) |
d691f9e8 | 8531 | type = BPF_READ; |
62c7989b DB |
8532 | else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) || |
8533 | insn->code == (BPF_STX | BPF_MEM | BPF_H) || | |
8534 | insn->code == (BPF_STX | BPF_MEM | BPF_W) || | |
ea2e7ce5 | 8535 | insn->code == (BPF_STX | BPF_MEM | BPF_DW)) |
d691f9e8 AS |
8536 | type = BPF_WRITE; |
8537 | else | |
9bac3d6d AS |
8538 | continue; |
8539 | ||
af86ca4e AS |
8540 | if (type == BPF_WRITE && |
8541 | env->insn_aux_data[i + delta].sanitize_stack_off) { | |
8542 | struct bpf_insn patch[] = { | |
8543 | /* Sanitize suspicious stack slot with zero. | |
8544 | * There are no memory dependencies for this store, | |
8545 | * since it's only using frame pointer and immediate | |
8546 | * constant of zero | |
8547 | */ | |
8548 | BPF_ST_MEM(BPF_DW, BPF_REG_FP, | |
8549 | env->insn_aux_data[i + delta].sanitize_stack_off, | |
8550 | 0), | |
8551 | /* the original STX instruction will immediately | |
8552 | * overwrite the same stack slot with appropriate value | |
8553 | */ | |
8554 | *insn, | |
8555 | }; | |
8556 | ||
8557 | cnt = ARRAY_SIZE(patch); | |
8558 | new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt); | |
8559 | if (!new_prog) | |
8560 | return -ENOMEM; | |
8561 | ||
8562 | delta += cnt - 1; | |
8563 | env->prog = new_prog; | |
8564 | insn = new_prog->insnsi + i + delta; | |
8565 | continue; | |
8566 | } | |
8567 | ||
c64b7983 JS |
8568 | switch (env->insn_aux_data[i + delta].ptr_type) { |
8569 | case PTR_TO_CTX: | |
8570 | if (!ops->convert_ctx_access) | |
8571 | continue; | |
8572 | convert_ctx_access = ops->convert_ctx_access; | |
8573 | break; | |
8574 | case PTR_TO_SOCKET: | |
46f8bc92 | 8575 | case PTR_TO_SOCK_COMMON: |
c64b7983 JS |
8576 | convert_ctx_access = bpf_sock_convert_ctx_access; |
8577 | break; | |
655a51e5 MKL |
8578 | case PTR_TO_TCP_SOCK: |
8579 | convert_ctx_access = bpf_tcp_sock_convert_ctx_access; | |
8580 | break; | |
fada7fdc JL |
8581 | case PTR_TO_XDP_SOCK: |
8582 | convert_ctx_access = bpf_xdp_sock_convert_ctx_access; | |
8583 | break; | |
c64b7983 | 8584 | default: |
9bac3d6d | 8585 | continue; |
c64b7983 | 8586 | } |
9bac3d6d | 8587 | |
31fd8581 | 8588 | ctx_field_size = env->insn_aux_data[i + delta].ctx_field_size; |
f96da094 | 8589 | size = BPF_LDST_BYTES(insn); |
31fd8581 YS |
8590 | |
8591 | /* If the read access is a narrower load of the field, | |
8592 | * convert to a 4/8-byte load, to minimum program type specific | |
8593 | * convert_ctx_access changes. If conversion is successful, | |
8594 | * we will apply proper mask to the result. | |
8595 | */ | |
f96da094 | 8596 | is_narrower_load = size < ctx_field_size; |
46f53a65 AI |
8597 | size_default = bpf_ctx_off_adjust_machine(ctx_field_size); |
8598 | off = insn->off; | |
31fd8581 | 8599 | if (is_narrower_load) { |
f96da094 DB |
8600 | u8 size_code; |
8601 | ||
8602 | if (type == BPF_WRITE) { | |
61bd5218 | 8603 | verbose(env, "bpf verifier narrow ctx access misconfigured\n"); |
f96da094 DB |
8604 | return -EINVAL; |
8605 | } | |
31fd8581 | 8606 | |
f96da094 | 8607 | size_code = BPF_H; |
31fd8581 YS |
8608 | if (ctx_field_size == 4) |
8609 | size_code = BPF_W; | |
8610 | else if (ctx_field_size == 8) | |
8611 | size_code = BPF_DW; | |
f96da094 | 8612 | |
bc23105c | 8613 | insn->off = off & ~(size_default - 1); |
31fd8581 YS |
8614 | insn->code = BPF_LDX | BPF_MEM | size_code; |
8615 | } | |
f96da094 DB |
8616 | |
8617 | target_size = 0; | |
c64b7983 JS |
8618 | cnt = convert_ctx_access(type, insn, insn_buf, env->prog, |
8619 | &target_size); | |
f96da094 DB |
8620 | if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) || |
8621 | (ctx_field_size && !target_size)) { | |
61bd5218 | 8622 | verbose(env, "bpf verifier is misconfigured\n"); |
9bac3d6d AS |
8623 | return -EINVAL; |
8624 | } | |
f96da094 DB |
8625 | |
8626 | if (is_narrower_load && size < target_size) { | |
d895a0f1 IL |
8627 | u8 shift = bpf_ctx_narrow_access_offset( |
8628 | off, size, size_default) * 8; | |
46f53a65 AI |
8629 | if (ctx_field_size <= 4) { |
8630 | if (shift) | |
8631 | insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH, | |
8632 | insn->dst_reg, | |
8633 | shift); | |
31fd8581 | 8634 | insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg, |
f96da094 | 8635 | (1 << size * 8) - 1); |
46f53a65 AI |
8636 | } else { |
8637 | if (shift) | |
8638 | insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH, | |
8639 | insn->dst_reg, | |
8640 | shift); | |
31fd8581 | 8641 | insn_buf[cnt++] = BPF_ALU64_IMM(BPF_AND, insn->dst_reg, |
e2f7fc0a | 8642 | (1ULL << size * 8) - 1); |
46f53a65 | 8643 | } |
31fd8581 | 8644 | } |
9bac3d6d | 8645 | |
8041902d | 8646 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); |
9bac3d6d AS |
8647 | if (!new_prog) |
8648 | return -ENOMEM; | |
8649 | ||
3df126f3 | 8650 | delta += cnt - 1; |
9bac3d6d AS |
8651 | |
8652 | /* keep walking new program and skip insns we just inserted */ | |
8653 | env->prog = new_prog; | |
3df126f3 | 8654 | insn = new_prog->insnsi + i + delta; |
9bac3d6d AS |
8655 | } |
8656 | ||
8657 | return 0; | |
8658 | } | |
8659 | ||
1c2a088a AS |
8660 | static int jit_subprogs(struct bpf_verifier_env *env) |
8661 | { | |
8662 | struct bpf_prog *prog = env->prog, **func, *tmp; | |
8663 | int i, j, subprog_start, subprog_end = 0, len, subprog; | |
7105e828 | 8664 | struct bpf_insn *insn; |
1c2a088a | 8665 | void *old_bpf_func; |
c454a46b | 8666 | int err; |
1c2a088a | 8667 | |
f910cefa | 8668 | if (env->subprog_cnt <= 1) |
1c2a088a AS |
8669 | return 0; |
8670 | ||
7105e828 | 8671 | for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { |
1c2a088a AS |
8672 | if (insn->code != (BPF_JMP | BPF_CALL) || |
8673 | insn->src_reg != BPF_PSEUDO_CALL) | |
8674 | continue; | |
c7a89784 DB |
8675 | /* Upon error here we cannot fall back to interpreter but |
8676 | * need a hard reject of the program. Thus -EFAULT is | |
8677 | * propagated in any case. | |
8678 | */ | |
1c2a088a AS |
8679 | subprog = find_subprog(env, i + insn->imm + 1); |
8680 | if (subprog < 0) { | |
8681 | WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", | |
8682 | i + insn->imm + 1); | |
8683 | return -EFAULT; | |
8684 | } | |
8685 | /* temporarily remember subprog id inside insn instead of | |
8686 | * aux_data, since next loop will split up all insns into funcs | |
8687 | */ | |
f910cefa | 8688 | insn->off = subprog; |
1c2a088a AS |
8689 | /* remember original imm in case JIT fails and fallback |
8690 | * to interpreter will be needed | |
8691 | */ | |
8692 | env->insn_aux_data[i].call_imm = insn->imm; | |
8693 | /* point imm to __bpf_call_base+1 from JITs point of view */ | |
8694 | insn->imm = 1; | |
8695 | } | |
8696 | ||
c454a46b MKL |
8697 | err = bpf_prog_alloc_jited_linfo(prog); |
8698 | if (err) | |
8699 | goto out_undo_insn; | |
8700 | ||
8701 | err = -ENOMEM; | |
6396bb22 | 8702 | func = kcalloc(env->subprog_cnt, sizeof(prog), GFP_KERNEL); |
1c2a088a | 8703 | if (!func) |
c7a89784 | 8704 | goto out_undo_insn; |
1c2a088a | 8705 | |
f910cefa | 8706 | for (i = 0; i < env->subprog_cnt; i++) { |
1c2a088a | 8707 | subprog_start = subprog_end; |
4cb3d99c | 8708 | subprog_end = env->subprog_info[i + 1].start; |
1c2a088a AS |
8709 | |
8710 | len = subprog_end - subprog_start; | |
492ecee8 AS |
8711 | /* BPF_PROG_RUN doesn't call subprogs directly, |
8712 | * hence main prog stats include the runtime of subprogs. | |
8713 | * subprogs don't have IDs and not reachable via prog_get_next_id | |
8714 | * func[i]->aux->stats will never be accessed and stays NULL | |
8715 | */ | |
8716 | func[i] = bpf_prog_alloc_no_stats(bpf_prog_size(len), GFP_USER); | |
1c2a088a AS |
8717 | if (!func[i]) |
8718 | goto out_free; | |
8719 | memcpy(func[i]->insnsi, &prog->insnsi[subprog_start], | |
8720 | len * sizeof(struct bpf_insn)); | |
4f74d809 | 8721 | func[i]->type = prog->type; |
1c2a088a | 8722 | func[i]->len = len; |
4f74d809 DB |
8723 | if (bpf_prog_calc_tag(func[i])) |
8724 | goto out_free; | |
1c2a088a | 8725 | func[i]->is_func = 1; |
ba64e7d8 YS |
8726 | func[i]->aux->func_idx = i; |
8727 | /* the btf and func_info will be freed only at prog->aux */ | |
8728 | func[i]->aux->btf = prog->aux->btf; | |
8729 | func[i]->aux->func_info = prog->aux->func_info; | |
8730 | ||
1c2a088a AS |
8731 | /* Use bpf_prog_F_tag to indicate functions in stack traces. |
8732 | * Long term would need debug info to populate names | |
8733 | */ | |
8734 | func[i]->aux->name[0] = 'F'; | |
9c8105bd | 8735 | func[i]->aux->stack_depth = env->subprog_info[i].stack_depth; |
1c2a088a | 8736 | func[i]->jit_requested = 1; |
c454a46b MKL |
8737 | func[i]->aux->linfo = prog->aux->linfo; |
8738 | func[i]->aux->nr_linfo = prog->aux->nr_linfo; | |
8739 | func[i]->aux->jited_linfo = prog->aux->jited_linfo; | |
8740 | func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx; | |
1c2a088a AS |
8741 | func[i] = bpf_int_jit_compile(func[i]); |
8742 | if (!func[i]->jited) { | |
8743 | err = -ENOTSUPP; | |
8744 | goto out_free; | |
8745 | } | |
8746 | cond_resched(); | |
8747 | } | |
8748 | /* at this point all bpf functions were successfully JITed | |
8749 | * now populate all bpf_calls with correct addresses and | |
8750 | * run last pass of JIT | |
8751 | */ | |
f910cefa | 8752 | for (i = 0; i < env->subprog_cnt; i++) { |
1c2a088a AS |
8753 | insn = func[i]->insnsi; |
8754 | for (j = 0; j < func[i]->len; j++, insn++) { | |
8755 | if (insn->code != (BPF_JMP | BPF_CALL) || | |
8756 | insn->src_reg != BPF_PSEUDO_CALL) | |
8757 | continue; | |
8758 | subprog = insn->off; | |
0d306c31 PB |
8759 | insn->imm = BPF_CAST_CALL(func[subprog]->bpf_func) - |
8760 | __bpf_call_base; | |
1c2a088a | 8761 | } |
2162fed4 SD |
8762 | |
8763 | /* we use the aux data to keep a list of the start addresses | |
8764 | * of the JITed images for each function in the program | |
8765 | * | |
8766 | * for some architectures, such as powerpc64, the imm field | |
8767 | * might not be large enough to hold the offset of the start | |
8768 | * address of the callee's JITed image from __bpf_call_base | |
8769 | * | |
8770 | * in such cases, we can lookup the start address of a callee | |
8771 | * by using its subprog id, available from the off field of | |
8772 | * the call instruction, as an index for this list | |
8773 | */ | |
8774 | func[i]->aux->func = func; | |
8775 | func[i]->aux->func_cnt = env->subprog_cnt; | |
1c2a088a | 8776 | } |
f910cefa | 8777 | for (i = 0; i < env->subprog_cnt; i++) { |
1c2a088a AS |
8778 | old_bpf_func = func[i]->bpf_func; |
8779 | tmp = bpf_int_jit_compile(func[i]); | |
8780 | if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) { | |
8781 | verbose(env, "JIT doesn't support bpf-to-bpf calls\n"); | |
c7a89784 | 8782 | err = -ENOTSUPP; |
1c2a088a AS |
8783 | goto out_free; |
8784 | } | |
8785 | cond_resched(); | |
8786 | } | |
8787 | ||
8788 | /* finally lock prog and jit images for all functions and | |
8789 | * populate kallsysm | |
8790 | */ | |
f910cefa | 8791 | for (i = 0; i < env->subprog_cnt; i++) { |
1c2a088a AS |
8792 | bpf_prog_lock_ro(func[i]); |
8793 | bpf_prog_kallsyms_add(func[i]); | |
8794 | } | |
7105e828 DB |
8795 | |
8796 | /* Last step: make now unused interpreter insns from main | |
8797 | * prog consistent for later dump requests, so they can | |
8798 | * later look the same as if they were interpreted only. | |
8799 | */ | |
8800 | for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { | |
7105e828 DB |
8801 | if (insn->code != (BPF_JMP | BPF_CALL) || |
8802 | insn->src_reg != BPF_PSEUDO_CALL) | |
8803 | continue; | |
8804 | insn->off = env->insn_aux_data[i].call_imm; | |
8805 | subprog = find_subprog(env, i + insn->off + 1); | |
dbecd738 | 8806 | insn->imm = subprog; |
7105e828 DB |
8807 | } |
8808 | ||
1c2a088a AS |
8809 | prog->jited = 1; |
8810 | prog->bpf_func = func[0]->bpf_func; | |
8811 | prog->aux->func = func; | |
f910cefa | 8812 | prog->aux->func_cnt = env->subprog_cnt; |
c454a46b | 8813 | bpf_prog_free_unused_jited_linfo(prog); |
1c2a088a AS |
8814 | return 0; |
8815 | out_free: | |
f910cefa | 8816 | for (i = 0; i < env->subprog_cnt; i++) |
1c2a088a AS |
8817 | if (func[i]) |
8818 | bpf_jit_free(func[i]); | |
8819 | kfree(func); | |
c7a89784 | 8820 | out_undo_insn: |
1c2a088a AS |
8821 | /* cleanup main prog to be interpreted */ |
8822 | prog->jit_requested = 0; | |
8823 | for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { | |
8824 | if (insn->code != (BPF_JMP | BPF_CALL) || | |
8825 | insn->src_reg != BPF_PSEUDO_CALL) | |
8826 | continue; | |
8827 | insn->off = 0; | |
8828 | insn->imm = env->insn_aux_data[i].call_imm; | |
8829 | } | |
c454a46b | 8830 | bpf_prog_free_jited_linfo(prog); |
1c2a088a AS |
8831 | return err; |
8832 | } | |
8833 | ||
1ea47e01 AS |
8834 | static int fixup_call_args(struct bpf_verifier_env *env) |
8835 | { | |
19d28fbd | 8836 | #ifndef CONFIG_BPF_JIT_ALWAYS_ON |
1ea47e01 AS |
8837 | struct bpf_prog *prog = env->prog; |
8838 | struct bpf_insn *insn = prog->insnsi; | |
8839 | int i, depth; | |
19d28fbd | 8840 | #endif |
e4052d06 | 8841 | int err = 0; |
1ea47e01 | 8842 | |
e4052d06 QM |
8843 | if (env->prog->jit_requested && |
8844 | !bpf_prog_is_dev_bound(env->prog->aux)) { | |
19d28fbd DM |
8845 | err = jit_subprogs(env); |
8846 | if (err == 0) | |
1c2a088a | 8847 | return 0; |
c7a89784 DB |
8848 | if (err == -EFAULT) |
8849 | return err; | |
19d28fbd DM |
8850 | } |
8851 | #ifndef CONFIG_BPF_JIT_ALWAYS_ON | |
1ea47e01 AS |
8852 | for (i = 0; i < prog->len; i++, insn++) { |
8853 | if (insn->code != (BPF_JMP | BPF_CALL) || | |
8854 | insn->src_reg != BPF_PSEUDO_CALL) | |
8855 | continue; | |
8856 | depth = get_callee_stack_depth(env, insn, i); | |
8857 | if (depth < 0) | |
8858 | return depth; | |
8859 | bpf_patch_call_args(insn, depth); | |
8860 | } | |
19d28fbd DM |
8861 | err = 0; |
8862 | #endif | |
8863 | return err; | |
1ea47e01 AS |
8864 | } |
8865 | ||
79741b3b | 8866 | /* fixup insn->imm field of bpf_call instructions |
81ed18ab | 8867 | * and inline eligible helpers as explicit sequence of BPF instructions |
e245c5c6 AS |
8868 | * |
8869 | * this function is called after eBPF program passed verification | |
8870 | */ | |
79741b3b | 8871 | static int fixup_bpf_calls(struct bpf_verifier_env *env) |
e245c5c6 | 8872 | { |
79741b3b AS |
8873 | struct bpf_prog *prog = env->prog; |
8874 | struct bpf_insn *insn = prog->insnsi; | |
e245c5c6 | 8875 | const struct bpf_func_proto *fn; |
79741b3b | 8876 | const int insn_cnt = prog->len; |
09772d92 | 8877 | const struct bpf_map_ops *ops; |
c93552c4 | 8878 | struct bpf_insn_aux_data *aux; |
81ed18ab AS |
8879 | struct bpf_insn insn_buf[16]; |
8880 | struct bpf_prog *new_prog; | |
8881 | struct bpf_map *map_ptr; | |
8882 | int i, cnt, delta = 0; | |
e245c5c6 | 8883 | |
79741b3b | 8884 | for (i = 0; i < insn_cnt; i++, insn++) { |
f6b1b3bf DB |
8885 | if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) || |
8886 | insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) || | |
8887 | insn->code == (BPF_ALU | BPF_MOD | BPF_X) || | |
68fda450 | 8888 | insn->code == (BPF_ALU | BPF_DIV | BPF_X)) { |
f6b1b3bf DB |
8889 | bool is64 = BPF_CLASS(insn->code) == BPF_ALU64; |
8890 | struct bpf_insn mask_and_div[] = { | |
8891 | BPF_MOV32_REG(insn->src_reg, insn->src_reg), | |
8892 | /* Rx div 0 -> 0 */ | |
8893 | BPF_JMP_IMM(BPF_JNE, insn->src_reg, 0, 2), | |
8894 | BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg), | |
8895 | BPF_JMP_IMM(BPF_JA, 0, 0, 1), | |
8896 | *insn, | |
8897 | }; | |
8898 | struct bpf_insn mask_and_mod[] = { | |
8899 | BPF_MOV32_REG(insn->src_reg, insn->src_reg), | |
8900 | /* Rx mod 0 -> Rx */ | |
8901 | BPF_JMP_IMM(BPF_JEQ, insn->src_reg, 0, 1), | |
8902 | *insn, | |
8903 | }; | |
8904 | struct bpf_insn *patchlet; | |
8905 | ||
8906 | if (insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) || | |
8907 | insn->code == (BPF_ALU | BPF_DIV | BPF_X)) { | |
8908 | patchlet = mask_and_div + (is64 ? 1 : 0); | |
8909 | cnt = ARRAY_SIZE(mask_and_div) - (is64 ? 1 : 0); | |
8910 | } else { | |
8911 | patchlet = mask_and_mod + (is64 ? 1 : 0); | |
8912 | cnt = ARRAY_SIZE(mask_and_mod) - (is64 ? 1 : 0); | |
8913 | } | |
8914 | ||
8915 | new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt); | |
68fda450 AS |
8916 | if (!new_prog) |
8917 | return -ENOMEM; | |
8918 | ||
8919 | delta += cnt - 1; | |
8920 | env->prog = prog = new_prog; | |
8921 | insn = new_prog->insnsi + i + delta; | |
8922 | continue; | |
8923 | } | |
8924 | ||
e0cea7ce DB |
8925 | if (BPF_CLASS(insn->code) == BPF_LD && |
8926 | (BPF_MODE(insn->code) == BPF_ABS || | |
8927 | BPF_MODE(insn->code) == BPF_IND)) { | |
8928 | cnt = env->ops->gen_ld_abs(insn, insn_buf); | |
8929 | if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) { | |
8930 | verbose(env, "bpf verifier is misconfigured\n"); | |
8931 | return -EINVAL; | |
8932 | } | |
8933 | ||
8934 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); | |
8935 | if (!new_prog) | |
8936 | return -ENOMEM; | |
8937 | ||
8938 | delta += cnt - 1; | |
8939 | env->prog = prog = new_prog; | |
8940 | insn = new_prog->insnsi + i + delta; | |
8941 | continue; | |
8942 | } | |
8943 | ||
979d63d5 DB |
8944 | if (insn->code == (BPF_ALU64 | BPF_ADD | BPF_X) || |
8945 | insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) { | |
8946 | const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X; | |
8947 | const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X; | |
8948 | struct bpf_insn insn_buf[16]; | |
8949 | struct bpf_insn *patch = &insn_buf[0]; | |
8950 | bool issrc, isneg; | |
8951 | u32 off_reg; | |
8952 | ||
8953 | aux = &env->insn_aux_data[i + delta]; | |
3612af78 DB |
8954 | if (!aux->alu_state || |
8955 | aux->alu_state == BPF_ALU_NON_POINTER) | |
979d63d5 DB |
8956 | continue; |
8957 | ||
8958 | isneg = aux->alu_state & BPF_ALU_NEG_VALUE; | |
8959 | issrc = (aux->alu_state & BPF_ALU_SANITIZE) == | |
8960 | BPF_ALU_SANITIZE_SRC; | |
8961 | ||
8962 | off_reg = issrc ? insn->src_reg : insn->dst_reg; | |
8963 | if (isneg) | |
8964 | *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1); | |
8965 | *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit - 1); | |
8966 | *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg); | |
8967 | *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg); | |
8968 | *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0); | |
8969 | *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63); | |
8970 | if (issrc) { | |
8971 | *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX, | |
8972 | off_reg); | |
8973 | insn->src_reg = BPF_REG_AX; | |
8974 | } else { | |
8975 | *patch++ = BPF_ALU64_REG(BPF_AND, off_reg, | |
8976 | BPF_REG_AX); | |
8977 | } | |
8978 | if (isneg) | |
8979 | insn->code = insn->code == code_add ? | |
8980 | code_sub : code_add; | |
8981 | *patch++ = *insn; | |
8982 | if (issrc && isneg) | |
8983 | *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1); | |
8984 | cnt = patch - insn_buf; | |
8985 | ||
8986 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); | |
8987 | if (!new_prog) | |
8988 | return -ENOMEM; | |
8989 | ||
8990 | delta += cnt - 1; | |
8991 | env->prog = prog = new_prog; | |
8992 | insn = new_prog->insnsi + i + delta; | |
8993 | continue; | |
8994 | } | |
8995 | ||
79741b3b AS |
8996 | if (insn->code != (BPF_JMP | BPF_CALL)) |
8997 | continue; | |
cc8b0b92 AS |
8998 | if (insn->src_reg == BPF_PSEUDO_CALL) |
8999 | continue; | |
e245c5c6 | 9000 | |
79741b3b AS |
9001 | if (insn->imm == BPF_FUNC_get_route_realm) |
9002 | prog->dst_needed = 1; | |
9003 | if (insn->imm == BPF_FUNC_get_prandom_u32) | |
9004 | bpf_user_rnd_init_once(); | |
9802d865 JB |
9005 | if (insn->imm == BPF_FUNC_override_return) |
9006 | prog->kprobe_override = 1; | |
79741b3b | 9007 | if (insn->imm == BPF_FUNC_tail_call) { |
7b9f6da1 DM |
9008 | /* If we tail call into other programs, we |
9009 | * cannot make any assumptions since they can | |
9010 | * be replaced dynamically during runtime in | |
9011 | * the program array. | |
9012 | */ | |
9013 | prog->cb_access = 1; | |
80a58d02 | 9014 | env->prog->aux->stack_depth = MAX_BPF_STACK; |
e647815a | 9015 | env->prog->aux->max_pkt_offset = MAX_PACKET_OFF; |
7b9f6da1 | 9016 | |
79741b3b AS |
9017 | /* mark bpf_tail_call as different opcode to avoid |
9018 | * conditional branch in the interpeter for every normal | |
9019 | * call and to prevent accidental JITing by JIT compiler | |
9020 | * that doesn't support bpf_tail_call yet | |
e245c5c6 | 9021 | */ |
79741b3b | 9022 | insn->imm = 0; |
71189fa9 | 9023 | insn->code = BPF_JMP | BPF_TAIL_CALL; |
b2157399 | 9024 | |
c93552c4 DB |
9025 | aux = &env->insn_aux_data[i + delta]; |
9026 | if (!bpf_map_ptr_unpriv(aux)) | |
9027 | continue; | |
9028 | ||
b2157399 AS |
9029 | /* instead of changing every JIT dealing with tail_call |
9030 | * emit two extra insns: | |
9031 | * if (index >= max_entries) goto out; | |
9032 | * index &= array->index_mask; | |
9033 | * to avoid out-of-bounds cpu speculation | |
9034 | */ | |
c93552c4 | 9035 | if (bpf_map_ptr_poisoned(aux)) { |
40950343 | 9036 | verbose(env, "tail_call abusing map_ptr\n"); |
b2157399 AS |
9037 | return -EINVAL; |
9038 | } | |
c93552c4 DB |
9039 | |
9040 | map_ptr = BPF_MAP_PTR(aux->map_state); | |
b2157399 AS |
9041 | insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3, |
9042 | map_ptr->max_entries, 2); | |
9043 | insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3, | |
9044 | container_of(map_ptr, | |
9045 | struct bpf_array, | |
9046 | map)->index_mask); | |
9047 | insn_buf[2] = *insn; | |
9048 | cnt = 3; | |
9049 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); | |
9050 | if (!new_prog) | |
9051 | return -ENOMEM; | |
9052 | ||
9053 | delta += cnt - 1; | |
9054 | env->prog = prog = new_prog; | |
9055 | insn = new_prog->insnsi + i + delta; | |
79741b3b AS |
9056 | continue; |
9057 | } | |
e245c5c6 | 9058 | |
89c63074 | 9059 | /* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup |
09772d92 DB |
9060 | * and other inlining handlers are currently limited to 64 bit |
9061 | * only. | |
89c63074 | 9062 | */ |
60b58afc | 9063 | if (prog->jit_requested && BITS_PER_LONG == 64 && |
09772d92 DB |
9064 | (insn->imm == BPF_FUNC_map_lookup_elem || |
9065 | insn->imm == BPF_FUNC_map_update_elem || | |
84430d42 DB |
9066 | insn->imm == BPF_FUNC_map_delete_elem || |
9067 | insn->imm == BPF_FUNC_map_push_elem || | |
9068 | insn->imm == BPF_FUNC_map_pop_elem || | |
9069 | insn->imm == BPF_FUNC_map_peek_elem)) { | |
c93552c4 DB |
9070 | aux = &env->insn_aux_data[i + delta]; |
9071 | if (bpf_map_ptr_poisoned(aux)) | |
9072 | goto patch_call_imm; | |
9073 | ||
9074 | map_ptr = BPF_MAP_PTR(aux->map_state); | |
09772d92 DB |
9075 | ops = map_ptr->ops; |
9076 | if (insn->imm == BPF_FUNC_map_lookup_elem && | |
9077 | ops->map_gen_lookup) { | |
9078 | cnt = ops->map_gen_lookup(map_ptr, insn_buf); | |
9079 | if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) { | |
9080 | verbose(env, "bpf verifier is misconfigured\n"); | |
9081 | return -EINVAL; | |
9082 | } | |
81ed18ab | 9083 | |
09772d92 DB |
9084 | new_prog = bpf_patch_insn_data(env, i + delta, |
9085 | insn_buf, cnt); | |
9086 | if (!new_prog) | |
9087 | return -ENOMEM; | |
81ed18ab | 9088 | |
09772d92 DB |
9089 | delta += cnt - 1; |
9090 | env->prog = prog = new_prog; | |
9091 | insn = new_prog->insnsi + i + delta; | |
9092 | continue; | |
9093 | } | |
81ed18ab | 9094 | |
09772d92 DB |
9095 | BUILD_BUG_ON(!__same_type(ops->map_lookup_elem, |
9096 | (void *(*)(struct bpf_map *map, void *key))NULL)); | |
9097 | BUILD_BUG_ON(!__same_type(ops->map_delete_elem, | |
9098 | (int (*)(struct bpf_map *map, void *key))NULL)); | |
9099 | BUILD_BUG_ON(!__same_type(ops->map_update_elem, | |
9100 | (int (*)(struct bpf_map *map, void *key, void *value, | |
9101 | u64 flags))NULL)); | |
84430d42 DB |
9102 | BUILD_BUG_ON(!__same_type(ops->map_push_elem, |
9103 | (int (*)(struct bpf_map *map, void *value, | |
9104 | u64 flags))NULL)); | |
9105 | BUILD_BUG_ON(!__same_type(ops->map_pop_elem, | |
9106 | (int (*)(struct bpf_map *map, void *value))NULL)); | |
9107 | BUILD_BUG_ON(!__same_type(ops->map_peek_elem, | |
9108 | (int (*)(struct bpf_map *map, void *value))NULL)); | |
9109 | ||
09772d92 DB |
9110 | switch (insn->imm) { |
9111 | case BPF_FUNC_map_lookup_elem: | |
9112 | insn->imm = BPF_CAST_CALL(ops->map_lookup_elem) - | |
9113 | __bpf_call_base; | |
9114 | continue; | |
9115 | case BPF_FUNC_map_update_elem: | |
9116 | insn->imm = BPF_CAST_CALL(ops->map_update_elem) - | |
9117 | __bpf_call_base; | |
9118 | continue; | |
9119 | case BPF_FUNC_map_delete_elem: | |
9120 | insn->imm = BPF_CAST_CALL(ops->map_delete_elem) - | |
9121 | __bpf_call_base; | |
9122 | continue; | |
84430d42 DB |
9123 | case BPF_FUNC_map_push_elem: |
9124 | insn->imm = BPF_CAST_CALL(ops->map_push_elem) - | |
9125 | __bpf_call_base; | |
9126 | continue; | |
9127 | case BPF_FUNC_map_pop_elem: | |
9128 | insn->imm = BPF_CAST_CALL(ops->map_pop_elem) - | |
9129 | __bpf_call_base; | |
9130 | continue; | |
9131 | case BPF_FUNC_map_peek_elem: | |
9132 | insn->imm = BPF_CAST_CALL(ops->map_peek_elem) - | |
9133 | __bpf_call_base; | |
9134 | continue; | |
09772d92 | 9135 | } |
81ed18ab | 9136 | |
09772d92 | 9137 | goto patch_call_imm; |
81ed18ab AS |
9138 | } |
9139 | ||
9140 | patch_call_imm: | |
5e43f899 | 9141 | fn = env->ops->get_func_proto(insn->imm, env->prog); |
79741b3b AS |
9142 | /* all functions that have prototype and verifier allowed |
9143 | * programs to call them, must be real in-kernel functions | |
9144 | */ | |
9145 | if (!fn->func) { | |
61bd5218 JK |
9146 | verbose(env, |
9147 | "kernel subsystem misconfigured func %s#%d\n", | |
79741b3b AS |
9148 | func_id_name(insn->imm), insn->imm); |
9149 | return -EFAULT; | |
e245c5c6 | 9150 | } |
79741b3b | 9151 | insn->imm = fn->func - __bpf_call_base; |
e245c5c6 | 9152 | } |
e245c5c6 | 9153 | |
79741b3b AS |
9154 | return 0; |
9155 | } | |
e245c5c6 | 9156 | |
58e2af8b | 9157 | static void free_states(struct bpf_verifier_env *env) |
f1bca824 | 9158 | { |
58e2af8b | 9159 | struct bpf_verifier_state_list *sl, *sln; |
f1bca824 AS |
9160 | int i; |
9161 | ||
9f4686c4 AS |
9162 | sl = env->free_list; |
9163 | while (sl) { | |
9164 | sln = sl->next; | |
9165 | free_verifier_state(&sl->state, false); | |
9166 | kfree(sl); | |
9167 | sl = sln; | |
9168 | } | |
9169 | ||
f1bca824 AS |
9170 | if (!env->explored_states) |
9171 | return; | |
9172 | ||
dc2a4ebc | 9173 | for (i = 0; i < state_htab_size(env); i++) { |
f1bca824 AS |
9174 | sl = env->explored_states[i]; |
9175 | ||
a8f500af AS |
9176 | while (sl) { |
9177 | sln = sl->next; | |
9178 | free_verifier_state(&sl->state, false); | |
9179 | kfree(sl); | |
9180 | sl = sln; | |
9181 | } | |
f1bca824 AS |
9182 | } |
9183 | ||
71dde681 | 9184 | kvfree(env->explored_states); |
f1bca824 AS |
9185 | } |
9186 | ||
06ee7115 AS |
9187 | static void print_verification_stats(struct bpf_verifier_env *env) |
9188 | { | |
9189 | int i; | |
9190 | ||
9191 | if (env->log.level & BPF_LOG_STATS) { | |
9192 | verbose(env, "verification time %lld usec\n", | |
9193 | div_u64(env->verification_time, 1000)); | |
9194 | verbose(env, "stack depth "); | |
9195 | for (i = 0; i < env->subprog_cnt; i++) { | |
9196 | u32 depth = env->subprog_info[i].stack_depth; | |
9197 | ||
9198 | verbose(env, "%d", depth); | |
9199 | if (i + 1 < env->subprog_cnt) | |
9200 | verbose(env, "+"); | |
9201 | } | |
9202 | verbose(env, "\n"); | |
9203 | } | |
9204 | verbose(env, "processed %d insns (limit %d) max_states_per_insn %d " | |
9205 | "total_states %d peak_states %d mark_read %d\n", | |
9206 | env->insn_processed, BPF_COMPLEXITY_LIMIT_INSNS, | |
9207 | env->max_states_per_insn, env->total_states, | |
9208 | env->peak_states, env->longest_mark_read_walk); | |
f1bca824 AS |
9209 | } |
9210 | ||
838e9690 YS |
9211 | int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, |
9212 | union bpf_attr __user *uattr) | |
51580e79 | 9213 | { |
06ee7115 | 9214 | u64 start_time = ktime_get_ns(); |
58e2af8b | 9215 | struct bpf_verifier_env *env; |
b9193c1b | 9216 | struct bpf_verifier_log *log; |
9e4c24e7 | 9217 | int i, len, ret = -EINVAL; |
e2ae4ca2 | 9218 | bool is_priv; |
51580e79 | 9219 | |
eba0c929 AB |
9220 | /* no program is valid */ |
9221 | if (ARRAY_SIZE(bpf_verifier_ops) == 0) | |
9222 | return -EINVAL; | |
9223 | ||
58e2af8b | 9224 | /* 'struct bpf_verifier_env' can be global, but since it's not small, |
cbd35700 AS |
9225 | * allocate/free it every time bpf_check() is called |
9226 | */ | |
58e2af8b | 9227 | env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL); |
cbd35700 AS |
9228 | if (!env) |
9229 | return -ENOMEM; | |
61bd5218 | 9230 | log = &env->log; |
cbd35700 | 9231 | |
9e4c24e7 | 9232 | len = (*prog)->len; |
fad953ce | 9233 | env->insn_aux_data = |
9e4c24e7 | 9234 | vzalloc(array_size(sizeof(struct bpf_insn_aux_data), len)); |
3df126f3 JK |
9235 | ret = -ENOMEM; |
9236 | if (!env->insn_aux_data) | |
9237 | goto err_free_env; | |
9e4c24e7 JK |
9238 | for (i = 0; i < len; i++) |
9239 | env->insn_aux_data[i].orig_idx = i; | |
9bac3d6d | 9240 | env->prog = *prog; |
00176a34 | 9241 | env->ops = bpf_verifier_ops[env->prog->type]; |
45a73c17 | 9242 | is_priv = capable(CAP_SYS_ADMIN); |
0246e64d | 9243 | |
cbd35700 | 9244 | /* grab the mutex to protect few globals used by verifier */ |
45a73c17 AS |
9245 | if (!is_priv) |
9246 | mutex_lock(&bpf_verifier_lock); | |
cbd35700 AS |
9247 | |
9248 | if (attr->log_level || attr->log_buf || attr->log_size) { | |
9249 | /* user requested verbose verifier output | |
9250 | * and supplied buffer to store the verification trace | |
9251 | */ | |
e7bf8249 JK |
9252 | log->level = attr->log_level; |
9253 | log->ubuf = (char __user *) (unsigned long) attr->log_buf; | |
9254 | log->len_total = attr->log_size; | |
cbd35700 AS |
9255 | |
9256 | ret = -EINVAL; | |
e7bf8249 | 9257 | /* log attributes have to be sane */ |
7a9f5c65 | 9258 | if (log->len_total < 128 || log->len_total > UINT_MAX >> 2 || |
06ee7115 | 9259 | !log->level || !log->ubuf || log->level & ~BPF_LOG_MASK) |
3df126f3 | 9260 | goto err_unlock; |
cbd35700 | 9261 | } |
1ad2f583 DB |
9262 | |
9263 | env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT); | |
9264 | if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) | |
e07b98d9 | 9265 | env->strict_alignment = true; |
e9ee9efc DM |
9266 | if (attr->prog_flags & BPF_F_ANY_ALIGNMENT) |
9267 | env->strict_alignment = false; | |
cbd35700 | 9268 | |
e2ae4ca2 JK |
9269 | env->allow_ptr_leaks = is_priv; |
9270 | ||
10d274e8 AS |
9271 | if (is_priv) |
9272 | env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ; | |
9273 | ||
f4e3ec0d JK |
9274 | ret = replace_map_fd_with_map_ptr(env); |
9275 | if (ret < 0) | |
9276 | goto skip_full_check; | |
9277 | ||
cae1927c | 9278 | if (bpf_prog_is_dev_bound(env->prog->aux)) { |
a40a2632 | 9279 | ret = bpf_prog_offload_verifier_prep(env->prog); |
ab3f0063 | 9280 | if (ret) |
f4e3ec0d | 9281 | goto skip_full_check; |
ab3f0063 JK |
9282 | } |
9283 | ||
dc2a4ebc | 9284 | env->explored_states = kvcalloc(state_htab_size(env), |
58e2af8b | 9285 | sizeof(struct bpf_verifier_state_list *), |
f1bca824 AS |
9286 | GFP_USER); |
9287 | ret = -ENOMEM; | |
9288 | if (!env->explored_states) | |
9289 | goto skip_full_check; | |
9290 | ||
d9762e84 | 9291 | ret = check_subprogs(env); |
475fb78f AS |
9292 | if (ret < 0) |
9293 | goto skip_full_check; | |
9294 | ||
c454a46b | 9295 | ret = check_btf_info(env, attr, uattr); |
838e9690 YS |
9296 | if (ret < 0) |
9297 | goto skip_full_check; | |
9298 | ||
d9762e84 MKL |
9299 | ret = check_cfg(env); |
9300 | if (ret < 0) | |
9301 | goto skip_full_check; | |
9302 | ||
17a52670 | 9303 | ret = do_check(env); |
8c01c4f8 CG |
9304 | if (env->cur_state) { |
9305 | free_verifier_state(env->cur_state, true); | |
9306 | env->cur_state = NULL; | |
9307 | } | |
cbd35700 | 9308 | |
c941ce9c QM |
9309 | if (ret == 0 && bpf_prog_is_dev_bound(env->prog->aux)) |
9310 | ret = bpf_prog_offload_finalize(env); | |
9311 | ||
0246e64d | 9312 | skip_full_check: |
638f5b90 | 9313 | while (!pop_stack(env, NULL, NULL)); |
f1bca824 | 9314 | free_states(env); |
0246e64d | 9315 | |
c131187d | 9316 | if (ret == 0) |
9b38c405 | 9317 | ret = check_max_stack_depth(env); |
c131187d | 9318 | |
9b38c405 | 9319 | /* instruction rewrites happen after this point */ |
e2ae4ca2 JK |
9320 | if (is_priv) { |
9321 | if (ret == 0) | |
9322 | opt_hard_wire_dead_code_branches(env); | |
52875a04 JK |
9323 | if (ret == 0) |
9324 | ret = opt_remove_dead_code(env); | |
a1b14abc JK |
9325 | if (ret == 0) |
9326 | ret = opt_remove_nops(env); | |
52875a04 JK |
9327 | } else { |
9328 | if (ret == 0) | |
9329 | sanitize_dead_code(env); | |
e2ae4ca2 JK |
9330 | } |
9331 | ||
9bac3d6d AS |
9332 | if (ret == 0) |
9333 | /* program is valid, convert *(u32*)(ctx + off) accesses */ | |
9334 | ret = convert_ctx_accesses(env); | |
9335 | ||
e245c5c6 | 9336 | if (ret == 0) |
79741b3b | 9337 | ret = fixup_bpf_calls(env); |
e245c5c6 | 9338 | |
a4b1d3c1 JW |
9339 | /* do 32-bit optimization after insn patching has done so those patched |
9340 | * insns could be handled correctly. | |
9341 | */ | |
d6c2308c JW |
9342 | if (ret == 0 && !bpf_prog_is_dev_bound(env->prog->aux)) { |
9343 | ret = opt_subreg_zext_lo32_rnd_hi32(env, attr); | |
9344 | env->prog->aux->verifier_zext = bpf_jit_needs_zext() ? !ret | |
9345 | : false; | |
a4b1d3c1 JW |
9346 | } |
9347 | ||
1ea47e01 AS |
9348 | if (ret == 0) |
9349 | ret = fixup_call_args(env); | |
9350 | ||
06ee7115 AS |
9351 | env->verification_time = ktime_get_ns() - start_time; |
9352 | print_verification_stats(env); | |
9353 | ||
a2a7d570 | 9354 | if (log->level && bpf_verifier_log_full(log)) |
cbd35700 | 9355 | ret = -ENOSPC; |
a2a7d570 | 9356 | if (log->level && !log->ubuf) { |
cbd35700 | 9357 | ret = -EFAULT; |
a2a7d570 | 9358 | goto err_release_maps; |
cbd35700 AS |
9359 | } |
9360 | ||
0246e64d AS |
9361 | if (ret == 0 && env->used_map_cnt) { |
9362 | /* if program passed verifier, update used_maps in bpf_prog_info */ | |
9bac3d6d AS |
9363 | env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt, |
9364 | sizeof(env->used_maps[0]), | |
9365 | GFP_KERNEL); | |
0246e64d | 9366 | |
9bac3d6d | 9367 | if (!env->prog->aux->used_maps) { |
0246e64d | 9368 | ret = -ENOMEM; |
a2a7d570 | 9369 | goto err_release_maps; |
0246e64d AS |
9370 | } |
9371 | ||
9bac3d6d | 9372 | memcpy(env->prog->aux->used_maps, env->used_maps, |
0246e64d | 9373 | sizeof(env->used_maps[0]) * env->used_map_cnt); |
9bac3d6d | 9374 | env->prog->aux->used_map_cnt = env->used_map_cnt; |
0246e64d AS |
9375 | |
9376 | /* program is valid. Convert pseudo bpf_ld_imm64 into generic | |
9377 | * bpf_ld_imm64 instructions | |
9378 | */ | |
9379 | convert_pseudo_ld_imm64(env); | |
9380 | } | |
cbd35700 | 9381 | |
ba64e7d8 YS |
9382 | if (ret == 0) |
9383 | adjust_btf_func(env); | |
9384 | ||
a2a7d570 | 9385 | err_release_maps: |
9bac3d6d | 9386 | if (!env->prog->aux->used_maps) |
0246e64d | 9387 | /* if we didn't copy map pointers into bpf_prog_info, release |
ab7f5bf0 | 9388 | * them now. Otherwise free_used_maps() will release them. |
0246e64d AS |
9389 | */ |
9390 | release_maps(env); | |
9bac3d6d | 9391 | *prog = env->prog; |
3df126f3 | 9392 | err_unlock: |
45a73c17 AS |
9393 | if (!is_priv) |
9394 | mutex_unlock(&bpf_verifier_lock); | |
3df126f3 JK |
9395 | vfree(env->insn_aux_data); |
9396 | err_free_env: | |
9397 | kfree(env); | |
51580e79 AS |
9398 | return ret; |
9399 | } |