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51580e79 | 1 | /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com |
969bf05e | 2 | * Copyright (c) 2016 Facebook |
51580e79 AS |
3 | * |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of version 2 of the GNU General Public | |
6 | * License as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but | |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | */ | |
13 | #include <linux/kernel.h> | |
14 | #include <linux/types.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/bpf.h> | |
58e2af8b | 17 | #include <linux/bpf_verifier.h> |
51580e79 AS |
18 | #include <linux/filter.h> |
19 | #include <net/netlink.h> | |
20 | #include <linux/file.h> | |
21 | #include <linux/vmalloc.h> | |
ebb676da | 22 | #include <linux/stringify.h> |
51580e79 AS |
23 | |
24 | /* bpf_check() is a static code analyzer that walks eBPF program | |
25 | * instruction by instruction and updates register/stack state. | |
26 | * All paths of conditional branches are analyzed until 'bpf_exit' insn. | |
27 | * | |
28 | * The first pass is depth-first-search to check that the program is a DAG. | |
29 | * It rejects the following programs: | |
30 | * - larger than BPF_MAXINSNS insns | |
31 | * - if loop is present (detected via back-edge) | |
32 | * - unreachable insns exist (shouldn't be a forest. program = one function) | |
33 | * - out of bounds or malformed jumps | |
34 | * The second pass is all possible path descent from the 1st insn. | |
35 | * Since it's analyzing all pathes through the program, the length of the | |
eba38a96 | 36 | * analysis is limited to 64k insn, which may be hit even if total number of |
51580e79 AS |
37 | * insn is less then 4K, but there are too many branches that change stack/regs. |
38 | * Number of 'branches to be analyzed' is limited to 1k | |
39 | * | |
40 | * On entry to each instruction, each register has a type, and the instruction | |
41 | * changes the types of the registers depending on instruction semantics. | |
42 | * If instruction is BPF_MOV64_REG(BPF_REG_1, BPF_REG_5), then type of R5 is | |
43 | * copied to R1. | |
44 | * | |
45 | * All registers are 64-bit. | |
46 | * R0 - return register | |
47 | * R1-R5 argument passing registers | |
48 | * R6-R9 callee saved registers | |
49 | * R10 - frame pointer read-only | |
50 | * | |
51 | * At the start of BPF program the register R1 contains a pointer to bpf_context | |
52 | * and has type PTR_TO_CTX. | |
53 | * | |
54 | * Verifier tracks arithmetic operations on pointers in case: | |
55 | * BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), | |
56 | * BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -20), | |
57 | * 1st insn copies R10 (which has FRAME_PTR) type into R1 | |
58 | * and 2nd arithmetic instruction is pattern matched to recognize | |
59 | * that it wants to construct a pointer to some element within stack. | |
60 | * So after 2nd insn, the register R1 has type PTR_TO_STACK | |
61 | * (and -20 constant is saved for further stack bounds checking). | |
62 | * Meaning that this reg is a pointer to stack plus known immediate constant. | |
63 | * | |
64 | * Most of the time the registers have UNKNOWN_VALUE type, which | |
65 | * means the register has some value, but it's not a valid pointer. | |
66 | * (like pointer plus pointer becomes UNKNOWN_VALUE type) | |
67 | * | |
68 | * When verifier sees load or store instructions the type of base register | |
69 | * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, FRAME_PTR. These are three pointer | |
70 | * types recognized by check_mem_access() function. | |
71 | * | |
72 | * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value' | |
73 | * and the range of [ptr, ptr + map's value_size) is accessible. | |
74 | * | |
75 | * registers used to pass values to function calls are checked against | |
76 | * function argument constraints. | |
77 | * | |
78 | * ARG_PTR_TO_MAP_KEY is one of such argument constraints. | |
79 | * It means that the register type passed to this function must be | |
80 | * PTR_TO_STACK and it will be used inside the function as | |
81 | * 'pointer to map element key' | |
82 | * | |
83 | * For example the argument constraints for bpf_map_lookup_elem(): | |
84 | * .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, | |
85 | * .arg1_type = ARG_CONST_MAP_PTR, | |
86 | * .arg2_type = ARG_PTR_TO_MAP_KEY, | |
87 | * | |
88 | * ret_type says that this function returns 'pointer to map elem value or null' | |
89 | * function expects 1st argument to be a const pointer to 'struct bpf_map' and | |
90 | * 2nd argument should be a pointer to stack, which will be used inside | |
91 | * the helper function as a pointer to map element key. | |
92 | * | |
93 | * On the kernel side the helper function looks like: | |
94 | * u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) | |
95 | * { | |
96 | * struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; | |
97 | * void *key = (void *) (unsigned long) r2; | |
98 | * void *value; | |
99 | * | |
100 | * here kernel can access 'key' and 'map' pointers safely, knowing that | |
101 | * [key, key + map->key_size) bytes are valid and were initialized on | |
102 | * the stack of eBPF program. | |
103 | * } | |
104 | * | |
105 | * Corresponding eBPF program may look like: | |
106 | * BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), // after this insn R2 type is FRAME_PTR | |
107 | * BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), // after this insn R2 type is PTR_TO_STACK | |
108 | * BPF_LD_MAP_FD(BPF_REG_1, map_fd), // after this insn R1 type is CONST_PTR_TO_MAP | |
109 | * BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem), | |
110 | * here verifier looks at prototype of map_lookup_elem() and sees: | |
111 | * .arg1_type == ARG_CONST_MAP_PTR and R1->type == CONST_PTR_TO_MAP, which is ok, | |
112 | * Now verifier knows that this map has key of R1->map_ptr->key_size bytes | |
113 | * | |
114 | * Then .arg2_type == ARG_PTR_TO_MAP_KEY and R2->type == PTR_TO_STACK, ok so far, | |
115 | * Now verifier checks that [R2, R2 + map's key_size) are within stack limits | |
116 | * and were initialized prior to this call. | |
117 | * If it's ok, then verifier allows this BPF_CALL insn and looks at | |
118 | * .ret_type which is RET_PTR_TO_MAP_VALUE_OR_NULL, so it sets | |
119 | * R0->type = PTR_TO_MAP_VALUE_OR_NULL which means bpf_map_lookup_elem() function | |
120 | * returns ether pointer to map value or NULL. | |
121 | * | |
122 | * When type PTR_TO_MAP_VALUE_OR_NULL passes through 'if (reg != 0) goto +off' | |
123 | * insn, the register holding that pointer in the true branch changes state to | |
124 | * PTR_TO_MAP_VALUE and the same register changes state to CONST_IMM in the false | |
125 | * branch. See check_cond_jmp_op(). | |
126 | * | |
127 | * After the call R0 is set to return type of the function and registers R1-R5 | |
128 | * are set to NOT_INIT to indicate that they are no longer readable. | |
129 | */ | |
130 | ||
17a52670 | 131 | /* verifier_state + insn_idx are pushed to stack when branch is encountered */ |
58e2af8b | 132 | struct bpf_verifier_stack_elem { |
17a52670 AS |
133 | /* verifer state is 'st' |
134 | * before processing instruction 'insn_idx' | |
135 | * and after processing instruction 'prev_insn_idx' | |
136 | */ | |
58e2af8b | 137 | struct bpf_verifier_state st; |
17a52670 AS |
138 | int insn_idx; |
139 | int prev_insn_idx; | |
58e2af8b | 140 | struct bpf_verifier_stack_elem *next; |
cbd35700 AS |
141 | }; |
142 | ||
3c2ce60b | 143 | #define BPF_COMPLEXITY_LIMIT_INSNS 98304 |
07016151 DB |
144 | #define BPF_COMPLEXITY_LIMIT_STACK 1024 |
145 | ||
fad73a1a MKL |
146 | #define BPF_MAP_PTR_POISON ((void *)0xeB9F + POISON_POINTER_DELTA) |
147 | ||
33ff9823 DB |
148 | struct bpf_call_arg_meta { |
149 | struct bpf_map *map_ptr; | |
435faee1 | 150 | bool raw_mode; |
36bbef52 | 151 | bool pkt_access; |
435faee1 DB |
152 | int regno; |
153 | int access_size; | |
33ff9823 DB |
154 | }; |
155 | ||
cbd35700 AS |
156 | /* verbose verifier prints what it's seeing |
157 | * bpf_check() is called under lock, so no race to access these global vars | |
158 | */ | |
159 | static u32 log_level, log_size, log_len; | |
160 | static char *log_buf; | |
161 | ||
162 | static DEFINE_MUTEX(bpf_verifier_lock); | |
163 | ||
164 | /* log_level controls verbosity level of eBPF verifier. | |
165 | * verbose() is used to dump the verification trace to the log, so the user | |
166 | * can figure out what's wrong with the program | |
167 | */ | |
1d056d9c | 168 | static __printf(1, 2) void verbose(const char *fmt, ...) |
cbd35700 AS |
169 | { |
170 | va_list args; | |
171 | ||
172 | if (log_level == 0 || log_len >= log_size - 1) | |
173 | return; | |
174 | ||
175 | va_start(args, fmt); | |
176 | log_len += vscnprintf(log_buf + log_len, log_size - log_len, fmt, args); | |
177 | va_end(args); | |
178 | } | |
179 | ||
17a52670 AS |
180 | /* string representation of 'enum bpf_reg_type' */ |
181 | static const char * const reg_type_str[] = { | |
182 | [NOT_INIT] = "?", | |
183 | [UNKNOWN_VALUE] = "inv", | |
184 | [PTR_TO_CTX] = "ctx", | |
185 | [CONST_PTR_TO_MAP] = "map_ptr", | |
186 | [PTR_TO_MAP_VALUE] = "map_value", | |
187 | [PTR_TO_MAP_VALUE_OR_NULL] = "map_value_or_null", | |
48461135 | 188 | [PTR_TO_MAP_VALUE_ADJ] = "map_value_adj", |
17a52670 AS |
189 | [FRAME_PTR] = "fp", |
190 | [PTR_TO_STACK] = "fp", | |
191 | [CONST_IMM] = "imm", | |
969bf05e AS |
192 | [PTR_TO_PACKET] = "pkt", |
193 | [PTR_TO_PACKET_END] = "pkt_end", | |
17a52670 AS |
194 | }; |
195 | ||
ebb676da TG |
196 | #define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x) |
197 | static const char * const func_id_str[] = { | |
198 | __BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN) | |
199 | }; | |
200 | #undef __BPF_FUNC_STR_FN | |
201 | ||
202 | static const char *func_id_name(int id) | |
203 | { | |
204 | BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID); | |
205 | ||
206 | if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id]) | |
207 | return func_id_str[id]; | |
208 | else | |
209 | return "unknown"; | |
210 | } | |
211 | ||
58e2af8b | 212 | static void print_verifier_state(struct bpf_verifier_state *state) |
17a52670 | 213 | { |
58e2af8b | 214 | struct bpf_reg_state *reg; |
17a52670 AS |
215 | enum bpf_reg_type t; |
216 | int i; | |
217 | ||
218 | for (i = 0; i < MAX_BPF_REG; i++) { | |
1a0dc1ac AS |
219 | reg = &state->regs[i]; |
220 | t = reg->type; | |
17a52670 AS |
221 | if (t == NOT_INIT) |
222 | continue; | |
223 | verbose(" R%d=%s", i, reg_type_str[t]); | |
224 | if (t == CONST_IMM || t == PTR_TO_STACK) | |
969bf05e AS |
225 | verbose("%lld", reg->imm); |
226 | else if (t == PTR_TO_PACKET) | |
227 | verbose("(id=%d,off=%d,r=%d)", | |
228 | reg->id, reg->off, reg->range); | |
229 | else if (t == UNKNOWN_VALUE && reg->imm) | |
230 | verbose("%lld", reg->imm); | |
17a52670 | 231 | else if (t == CONST_PTR_TO_MAP || t == PTR_TO_MAP_VALUE || |
48461135 JB |
232 | t == PTR_TO_MAP_VALUE_OR_NULL || |
233 | t == PTR_TO_MAP_VALUE_ADJ) | |
57a09bf0 | 234 | verbose("(ks=%d,vs=%d,id=%u)", |
1a0dc1ac | 235 | reg->map_ptr->key_size, |
57a09bf0 TG |
236 | reg->map_ptr->value_size, |
237 | reg->id); | |
48461135 | 238 | if (reg->min_value != BPF_REGISTER_MIN_RANGE) |
f23cc643 JB |
239 | verbose(",min_value=%lld", |
240 | (long long)reg->min_value); | |
48461135 JB |
241 | if (reg->max_value != BPF_REGISTER_MAX_RANGE) |
242 | verbose(",max_value=%llu", | |
243 | (unsigned long long)reg->max_value); | |
d1174416 DM |
244 | if (reg->min_align) |
245 | verbose(",min_align=%u", reg->min_align); | |
246 | if (reg->aux_off) | |
247 | verbose(",aux_off=%u", reg->aux_off); | |
248 | if (reg->aux_off_align) | |
249 | verbose(",aux_off_align=%u", reg->aux_off_align); | |
17a52670 | 250 | } |
9c399760 | 251 | for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) { |
1a0dc1ac | 252 | if (state->stack_slot_type[i] == STACK_SPILL) |
17a52670 | 253 | verbose(" fp%d=%s", -MAX_BPF_STACK + i, |
1a0dc1ac | 254 | reg_type_str[state->spilled_regs[i / BPF_REG_SIZE].type]); |
17a52670 AS |
255 | } |
256 | verbose("\n"); | |
257 | } | |
258 | ||
cbd35700 AS |
259 | static const char *const bpf_class_string[] = { |
260 | [BPF_LD] = "ld", | |
261 | [BPF_LDX] = "ldx", | |
262 | [BPF_ST] = "st", | |
263 | [BPF_STX] = "stx", | |
264 | [BPF_ALU] = "alu", | |
265 | [BPF_JMP] = "jmp", | |
266 | [BPF_RET] = "BUG", | |
267 | [BPF_ALU64] = "alu64", | |
268 | }; | |
269 | ||
687f0715 | 270 | static const char *const bpf_alu_string[16] = { |
cbd35700 AS |
271 | [BPF_ADD >> 4] = "+=", |
272 | [BPF_SUB >> 4] = "-=", | |
273 | [BPF_MUL >> 4] = "*=", | |
274 | [BPF_DIV >> 4] = "/=", | |
275 | [BPF_OR >> 4] = "|=", | |
276 | [BPF_AND >> 4] = "&=", | |
277 | [BPF_LSH >> 4] = "<<=", | |
278 | [BPF_RSH >> 4] = ">>=", | |
279 | [BPF_NEG >> 4] = "neg", | |
280 | [BPF_MOD >> 4] = "%=", | |
281 | [BPF_XOR >> 4] = "^=", | |
282 | [BPF_MOV >> 4] = "=", | |
283 | [BPF_ARSH >> 4] = "s>>=", | |
284 | [BPF_END >> 4] = "endian", | |
285 | }; | |
286 | ||
287 | static const char *const bpf_ldst_string[] = { | |
288 | [BPF_W >> 3] = "u32", | |
289 | [BPF_H >> 3] = "u16", | |
290 | [BPF_B >> 3] = "u8", | |
291 | [BPF_DW >> 3] = "u64", | |
292 | }; | |
293 | ||
687f0715 | 294 | static const char *const bpf_jmp_string[16] = { |
cbd35700 AS |
295 | [BPF_JA >> 4] = "jmp", |
296 | [BPF_JEQ >> 4] = "==", | |
297 | [BPF_JGT >> 4] = ">", | |
298 | [BPF_JGE >> 4] = ">=", | |
299 | [BPF_JSET >> 4] = "&", | |
300 | [BPF_JNE >> 4] = "!=", | |
301 | [BPF_JSGT >> 4] = "s>", | |
302 | [BPF_JSGE >> 4] = "s>=", | |
303 | [BPF_CALL >> 4] = "call", | |
304 | [BPF_EXIT >> 4] = "exit", | |
305 | }; | |
306 | ||
0d0e5769 DB |
307 | static void print_bpf_insn(const struct bpf_verifier_env *env, |
308 | const struct bpf_insn *insn) | |
cbd35700 AS |
309 | { |
310 | u8 class = BPF_CLASS(insn->code); | |
311 | ||
312 | if (class == BPF_ALU || class == BPF_ALU64) { | |
313 | if (BPF_SRC(insn->code) == BPF_X) | |
314 | verbose("(%02x) %sr%d %s %sr%d\n", | |
315 | insn->code, class == BPF_ALU ? "(u32) " : "", | |
316 | insn->dst_reg, | |
317 | bpf_alu_string[BPF_OP(insn->code) >> 4], | |
318 | class == BPF_ALU ? "(u32) " : "", | |
319 | insn->src_reg); | |
320 | else | |
321 | verbose("(%02x) %sr%d %s %s%d\n", | |
322 | insn->code, class == BPF_ALU ? "(u32) " : "", | |
323 | insn->dst_reg, | |
324 | bpf_alu_string[BPF_OP(insn->code) >> 4], | |
325 | class == BPF_ALU ? "(u32) " : "", | |
326 | insn->imm); | |
327 | } else if (class == BPF_STX) { | |
328 | if (BPF_MODE(insn->code) == BPF_MEM) | |
329 | verbose("(%02x) *(%s *)(r%d %+d) = r%d\n", | |
330 | insn->code, | |
331 | bpf_ldst_string[BPF_SIZE(insn->code) >> 3], | |
332 | insn->dst_reg, | |
333 | insn->off, insn->src_reg); | |
334 | else if (BPF_MODE(insn->code) == BPF_XADD) | |
335 | verbose("(%02x) lock *(%s *)(r%d %+d) += r%d\n", | |
336 | insn->code, | |
337 | bpf_ldst_string[BPF_SIZE(insn->code) >> 3], | |
338 | insn->dst_reg, insn->off, | |
339 | insn->src_reg); | |
340 | else | |
341 | verbose("BUG_%02x\n", insn->code); | |
342 | } else if (class == BPF_ST) { | |
343 | if (BPF_MODE(insn->code) != BPF_MEM) { | |
344 | verbose("BUG_st_%02x\n", insn->code); | |
345 | return; | |
346 | } | |
347 | verbose("(%02x) *(%s *)(r%d %+d) = %d\n", | |
348 | insn->code, | |
349 | bpf_ldst_string[BPF_SIZE(insn->code) >> 3], | |
350 | insn->dst_reg, | |
351 | insn->off, insn->imm); | |
352 | } else if (class == BPF_LDX) { | |
353 | if (BPF_MODE(insn->code) != BPF_MEM) { | |
354 | verbose("BUG_ldx_%02x\n", insn->code); | |
355 | return; | |
356 | } | |
357 | verbose("(%02x) r%d = *(%s *)(r%d %+d)\n", | |
358 | insn->code, insn->dst_reg, | |
359 | bpf_ldst_string[BPF_SIZE(insn->code) >> 3], | |
360 | insn->src_reg, insn->off); | |
361 | } else if (class == BPF_LD) { | |
362 | if (BPF_MODE(insn->code) == BPF_ABS) { | |
363 | verbose("(%02x) r0 = *(%s *)skb[%d]\n", | |
364 | insn->code, | |
365 | bpf_ldst_string[BPF_SIZE(insn->code) >> 3], | |
366 | insn->imm); | |
367 | } else if (BPF_MODE(insn->code) == BPF_IND) { | |
368 | verbose("(%02x) r0 = *(%s *)skb[r%d + %d]\n", | |
369 | insn->code, | |
370 | bpf_ldst_string[BPF_SIZE(insn->code) >> 3], | |
371 | insn->src_reg, insn->imm); | |
0d0e5769 DB |
372 | } else if (BPF_MODE(insn->code) == BPF_IMM && |
373 | BPF_SIZE(insn->code) == BPF_DW) { | |
374 | /* At this point, we already made sure that the second | |
375 | * part of the ldimm64 insn is accessible. | |
376 | */ | |
377 | u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; | |
378 | bool map_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD; | |
379 | ||
380 | if (map_ptr && !env->allow_ptr_leaks) | |
381 | imm = 0; | |
382 | ||
383 | verbose("(%02x) r%d = 0x%llx\n", insn->code, | |
384 | insn->dst_reg, (unsigned long long)imm); | |
cbd35700 AS |
385 | } else { |
386 | verbose("BUG_ld_%02x\n", insn->code); | |
387 | return; | |
388 | } | |
389 | } else if (class == BPF_JMP) { | |
390 | u8 opcode = BPF_OP(insn->code); | |
391 | ||
392 | if (opcode == BPF_CALL) { | |
ebb676da TG |
393 | verbose("(%02x) call %s#%d\n", insn->code, |
394 | func_id_name(insn->imm), insn->imm); | |
cbd35700 AS |
395 | } else if (insn->code == (BPF_JMP | BPF_JA)) { |
396 | verbose("(%02x) goto pc%+d\n", | |
397 | insn->code, insn->off); | |
398 | } else if (insn->code == (BPF_JMP | BPF_EXIT)) { | |
399 | verbose("(%02x) exit\n", insn->code); | |
400 | } else if (BPF_SRC(insn->code) == BPF_X) { | |
401 | verbose("(%02x) if r%d %s r%d goto pc%+d\n", | |
402 | insn->code, insn->dst_reg, | |
403 | bpf_jmp_string[BPF_OP(insn->code) >> 4], | |
404 | insn->src_reg, insn->off); | |
405 | } else { | |
406 | verbose("(%02x) if r%d %s 0x%x goto pc%+d\n", | |
407 | insn->code, insn->dst_reg, | |
408 | bpf_jmp_string[BPF_OP(insn->code) >> 4], | |
409 | insn->imm, insn->off); | |
410 | } | |
411 | } else { | |
412 | verbose("(%02x) %s\n", insn->code, bpf_class_string[class]); | |
413 | } | |
414 | } | |
415 | ||
58e2af8b | 416 | static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx) |
17a52670 | 417 | { |
58e2af8b | 418 | struct bpf_verifier_stack_elem *elem; |
17a52670 AS |
419 | int insn_idx; |
420 | ||
421 | if (env->head == NULL) | |
422 | return -1; | |
423 | ||
424 | memcpy(&env->cur_state, &env->head->st, sizeof(env->cur_state)); | |
425 | insn_idx = env->head->insn_idx; | |
426 | if (prev_insn_idx) | |
427 | *prev_insn_idx = env->head->prev_insn_idx; | |
428 | elem = env->head->next; | |
429 | kfree(env->head); | |
430 | env->head = elem; | |
431 | env->stack_size--; | |
432 | return insn_idx; | |
433 | } | |
434 | ||
58e2af8b JK |
435 | static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env, |
436 | int insn_idx, int prev_insn_idx) | |
17a52670 | 437 | { |
58e2af8b | 438 | struct bpf_verifier_stack_elem *elem; |
17a52670 | 439 | |
58e2af8b | 440 | elem = kmalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL); |
17a52670 AS |
441 | if (!elem) |
442 | goto err; | |
443 | ||
444 | memcpy(&elem->st, &env->cur_state, sizeof(env->cur_state)); | |
445 | elem->insn_idx = insn_idx; | |
446 | elem->prev_insn_idx = prev_insn_idx; | |
447 | elem->next = env->head; | |
448 | env->head = elem; | |
449 | env->stack_size++; | |
07016151 | 450 | if (env->stack_size > BPF_COMPLEXITY_LIMIT_STACK) { |
17a52670 AS |
451 | verbose("BPF program is too complex\n"); |
452 | goto err; | |
453 | } | |
454 | return &elem->st; | |
455 | err: | |
456 | /* pop all elements and return */ | |
457 | while (pop_stack(env, NULL) >= 0); | |
458 | return NULL; | |
459 | } | |
460 | ||
461 | #define CALLER_SAVED_REGS 6 | |
462 | static const int caller_saved[CALLER_SAVED_REGS] = { | |
463 | BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5 | |
464 | }; | |
465 | ||
a9789ef9 DB |
466 | static void mark_reg_not_init(struct bpf_reg_state *regs, u32 regno) |
467 | { | |
468 | BUG_ON(regno >= MAX_BPF_REG); | |
469 | ||
470 | memset(®s[regno], 0, sizeof(regs[regno])); | |
471 | regs[regno].type = NOT_INIT; | |
472 | regs[regno].min_value = BPF_REGISTER_MIN_RANGE; | |
473 | regs[regno].max_value = BPF_REGISTER_MAX_RANGE; | |
474 | } | |
475 | ||
58e2af8b | 476 | static void init_reg_state(struct bpf_reg_state *regs) |
17a52670 AS |
477 | { |
478 | int i; | |
479 | ||
a9789ef9 DB |
480 | for (i = 0; i < MAX_BPF_REG; i++) |
481 | mark_reg_not_init(regs, i); | |
17a52670 AS |
482 | |
483 | /* frame pointer */ | |
484 | regs[BPF_REG_FP].type = FRAME_PTR; | |
485 | ||
486 | /* 1st arg to a function */ | |
487 | regs[BPF_REG_1].type = PTR_TO_CTX; | |
488 | } | |
489 | ||
6760bf2d | 490 | static void __mark_reg_unknown_value(struct bpf_reg_state *regs, u32 regno) |
17a52670 | 491 | { |
17a52670 | 492 | regs[regno].type = UNKNOWN_VALUE; |
57a09bf0 | 493 | regs[regno].id = 0; |
17a52670 | 494 | regs[regno].imm = 0; |
17a52670 AS |
495 | } |
496 | ||
6760bf2d DB |
497 | static void mark_reg_unknown_value(struct bpf_reg_state *regs, u32 regno) |
498 | { | |
499 | BUG_ON(regno >= MAX_BPF_REG); | |
500 | __mark_reg_unknown_value(regs, regno); | |
501 | } | |
502 | ||
48461135 JB |
503 | static void reset_reg_range_values(struct bpf_reg_state *regs, u32 regno) |
504 | { | |
505 | regs[regno].min_value = BPF_REGISTER_MIN_RANGE; | |
506 | regs[regno].max_value = BPF_REGISTER_MAX_RANGE; | |
4cabc5b1 | 507 | regs[regno].value_from_signed = false; |
d1174416 | 508 | regs[regno].min_align = 0; |
48461135 JB |
509 | } |
510 | ||
f0318d01 GB |
511 | static void mark_reg_unknown_value_and_range(struct bpf_reg_state *regs, |
512 | u32 regno) | |
513 | { | |
514 | mark_reg_unknown_value(regs, regno); | |
515 | reset_reg_range_values(regs, regno); | |
516 | } | |
517 | ||
17a52670 AS |
518 | enum reg_arg_type { |
519 | SRC_OP, /* register is used as source operand */ | |
520 | DST_OP, /* register is used as destination operand */ | |
521 | DST_OP_NO_MARK /* same as above, check only, don't mark */ | |
522 | }; | |
523 | ||
58e2af8b | 524 | static int check_reg_arg(struct bpf_reg_state *regs, u32 regno, |
17a52670 AS |
525 | enum reg_arg_type t) |
526 | { | |
527 | if (regno >= MAX_BPF_REG) { | |
528 | verbose("R%d is invalid\n", regno); | |
529 | return -EINVAL; | |
530 | } | |
531 | ||
532 | if (t == SRC_OP) { | |
533 | /* check whether register used as source operand can be read */ | |
534 | if (regs[regno].type == NOT_INIT) { | |
535 | verbose("R%d !read_ok\n", regno); | |
536 | return -EACCES; | |
537 | } | |
538 | } else { | |
539 | /* check whether register used as dest operand can be written to */ | |
540 | if (regno == BPF_REG_FP) { | |
541 | verbose("frame pointer is read only\n"); | |
542 | return -EACCES; | |
543 | } | |
544 | if (t == DST_OP) | |
545 | mark_reg_unknown_value(regs, regno); | |
546 | } | |
547 | return 0; | |
548 | } | |
549 | ||
1be7f75d AS |
550 | static bool is_spillable_regtype(enum bpf_reg_type type) |
551 | { | |
552 | switch (type) { | |
553 | case PTR_TO_MAP_VALUE: | |
554 | case PTR_TO_MAP_VALUE_OR_NULL: | |
f0318d01 | 555 | case PTR_TO_MAP_VALUE_ADJ: |
1be7f75d AS |
556 | case PTR_TO_STACK: |
557 | case PTR_TO_CTX: | |
969bf05e AS |
558 | case PTR_TO_PACKET: |
559 | case PTR_TO_PACKET_END: | |
1be7f75d AS |
560 | case FRAME_PTR: |
561 | case CONST_PTR_TO_MAP: | |
562 | return true; | |
563 | default: | |
564 | return false; | |
565 | } | |
566 | } | |
567 | ||
17a52670 AS |
568 | /* check_stack_read/write functions track spill/fill of registers, |
569 | * stack boundary and alignment are checked in check_mem_access() | |
570 | */ | |
58e2af8b JK |
571 | static int check_stack_write(struct bpf_verifier_state *state, int off, |
572 | int size, int value_regno) | |
17a52670 | 573 | { |
17a52670 | 574 | int i; |
9c399760 AS |
575 | /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0, |
576 | * so it's aligned access and [off, off + size) are within stack limits | |
577 | */ | |
17a52670 AS |
578 | |
579 | if (value_regno >= 0 && | |
1be7f75d | 580 | is_spillable_regtype(state->regs[value_regno].type)) { |
17a52670 AS |
581 | |
582 | /* register containing pointer is being spilled into stack */ | |
9c399760 | 583 | if (size != BPF_REG_SIZE) { |
17a52670 AS |
584 | verbose("invalid size of register spill\n"); |
585 | return -EACCES; | |
586 | } | |
587 | ||
17a52670 | 588 | /* save register state */ |
9c399760 AS |
589 | state->spilled_regs[(MAX_BPF_STACK + off) / BPF_REG_SIZE] = |
590 | state->regs[value_regno]; | |
17a52670 | 591 | |
9c399760 AS |
592 | for (i = 0; i < BPF_REG_SIZE; i++) |
593 | state->stack_slot_type[MAX_BPF_STACK + off + i] = STACK_SPILL; | |
594 | } else { | |
17a52670 | 595 | /* regular write of data into stack */ |
9c399760 | 596 | state->spilled_regs[(MAX_BPF_STACK + off) / BPF_REG_SIZE] = |
58e2af8b | 597 | (struct bpf_reg_state) {}; |
9c399760 AS |
598 | |
599 | for (i = 0; i < size; i++) | |
600 | state->stack_slot_type[MAX_BPF_STACK + off + i] = STACK_MISC; | |
17a52670 AS |
601 | } |
602 | return 0; | |
603 | } | |
604 | ||
58e2af8b | 605 | static int check_stack_read(struct bpf_verifier_state *state, int off, int size, |
17a52670 AS |
606 | int value_regno) |
607 | { | |
9c399760 | 608 | u8 *slot_type; |
17a52670 | 609 | int i; |
17a52670 | 610 | |
9c399760 | 611 | slot_type = &state->stack_slot_type[MAX_BPF_STACK + off]; |
17a52670 | 612 | |
9c399760 AS |
613 | if (slot_type[0] == STACK_SPILL) { |
614 | if (size != BPF_REG_SIZE) { | |
17a52670 AS |
615 | verbose("invalid size of register spill\n"); |
616 | return -EACCES; | |
617 | } | |
9c399760 AS |
618 | for (i = 1; i < BPF_REG_SIZE; i++) { |
619 | if (slot_type[i] != STACK_SPILL) { | |
17a52670 AS |
620 | verbose("corrupted spill memory\n"); |
621 | return -EACCES; | |
622 | } | |
623 | } | |
624 | ||
625 | if (value_regno >= 0) | |
626 | /* restore register state from stack */ | |
9c399760 AS |
627 | state->regs[value_regno] = |
628 | state->spilled_regs[(MAX_BPF_STACK + off) / BPF_REG_SIZE]; | |
17a52670 AS |
629 | return 0; |
630 | } else { | |
631 | for (i = 0; i < size; i++) { | |
9c399760 | 632 | if (slot_type[i] != STACK_MISC) { |
17a52670 AS |
633 | verbose("invalid read from stack off %d+%d size %d\n", |
634 | off, i, size); | |
635 | return -EACCES; | |
636 | } | |
637 | } | |
638 | if (value_regno >= 0) | |
639 | /* have read misc data from the stack */ | |
f0318d01 GB |
640 | mark_reg_unknown_value_and_range(state->regs, |
641 | value_regno); | |
17a52670 AS |
642 | return 0; |
643 | } | |
644 | } | |
645 | ||
646 | /* check read/write into map element returned by bpf_map_lookup_elem() */ | |
58e2af8b | 647 | static int check_map_access(struct bpf_verifier_env *env, u32 regno, int off, |
17a52670 AS |
648 | int size) |
649 | { | |
650 | struct bpf_map *map = env->cur_state.regs[regno].map_ptr; | |
651 | ||
5722569b | 652 | if (off < 0 || size <= 0 || off + size > map->value_size) { |
17a52670 AS |
653 | verbose("invalid access to map value, value_size=%d off=%d size=%d\n", |
654 | map->value_size, off, size); | |
655 | return -EACCES; | |
656 | } | |
657 | return 0; | |
658 | } | |
659 | ||
dbcfe5f7 GB |
660 | /* check read/write into an adjusted map element */ |
661 | static int check_map_access_adj(struct bpf_verifier_env *env, u32 regno, | |
662 | int off, int size) | |
663 | { | |
664 | struct bpf_verifier_state *state = &env->cur_state; | |
665 | struct bpf_reg_state *reg = &state->regs[regno]; | |
666 | int err; | |
667 | ||
668 | /* We adjusted the register to this map value, so we | |
669 | * need to change off and size to min_value and max_value | |
670 | * respectively to make sure our theoretical access will be | |
671 | * safe. | |
672 | */ | |
673 | if (log_level) | |
674 | print_verifier_state(state); | |
675 | env->varlen_map_value_access = true; | |
676 | /* The minimum value is only important with signed | |
677 | * comparisons where we can't assume the floor of a | |
678 | * value is 0. If we are using signed variables for our | |
679 | * index'es we need to make sure that whatever we use | |
680 | * will have a set floor within our range. | |
681 | */ | |
682 | if (reg->min_value < 0) { | |
683 | verbose("R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n", | |
684 | regno); | |
685 | return -EACCES; | |
686 | } | |
687 | err = check_map_access(env, regno, reg->min_value + off, size); | |
688 | if (err) { | |
689 | verbose("R%d min value is outside of the array range\n", | |
690 | regno); | |
691 | return err; | |
692 | } | |
693 | ||
694 | /* If we haven't set a max value then we need to bail | |
695 | * since we can't be sure we won't do bad things. | |
696 | */ | |
697 | if (reg->max_value == BPF_REGISTER_MAX_RANGE) { | |
698 | verbose("R%d unbounded memory access, make sure to bounds check any array access into a map\n", | |
699 | regno); | |
700 | return -EACCES; | |
701 | } | |
702 | return check_map_access(env, regno, reg->max_value + off, size); | |
703 | } | |
704 | ||
969bf05e AS |
705 | #define MAX_PACKET_OFF 0xffff |
706 | ||
58e2af8b | 707 | static bool may_access_direct_pkt_data(struct bpf_verifier_env *env, |
3a0af8fd TG |
708 | const struct bpf_call_arg_meta *meta, |
709 | enum bpf_access_type t) | |
4acf6c0b | 710 | { |
36bbef52 | 711 | switch (env->prog->type) { |
3a0af8fd TG |
712 | case BPF_PROG_TYPE_LWT_IN: |
713 | case BPF_PROG_TYPE_LWT_OUT: | |
714 | /* dst_input() and dst_output() can't write for now */ | |
715 | if (t == BPF_WRITE) | |
716 | return false; | |
7e57fbb2 | 717 | /* fallthrough */ |
36bbef52 DB |
718 | case BPF_PROG_TYPE_SCHED_CLS: |
719 | case BPF_PROG_TYPE_SCHED_ACT: | |
4acf6c0b | 720 | case BPF_PROG_TYPE_XDP: |
3a0af8fd | 721 | case BPF_PROG_TYPE_LWT_XMIT: |
36bbef52 DB |
722 | if (meta) |
723 | return meta->pkt_access; | |
724 | ||
725 | env->seen_direct_write = true; | |
4acf6c0b BB |
726 | return true; |
727 | default: | |
728 | return false; | |
729 | } | |
730 | } | |
731 | ||
58e2af8b | 732 | static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, |
969bf05e AS |
733 | int size) |
734 | { | |
58e2af8b JK |
735 | struct bpf_reg_state *regs = env->cur_state.regs; |
736 | struct bpf_reg_state *reg = ®s[regno]; | |
969bf05e | 737 | |
d91b28ed | 738 | off += reg->off; |
b399cf64 | 739 | if (off < 0 || size <= 0 || off + size > reg->range) { |
d91b28ed AS |
740 | verbose("invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n", |
741 | off, size, regno, reg->id, reg->off, reg->range); | |
969bf05e AS |
742 | return -EACCES; |
743 | } | |
744 | return 0; | |
745 | } | |
746 | ||
17a52670 | 747 | /* check access to 'struct bpf_context' fields */ |
31fd8581 | 748 | static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size, |
19de99f7 | 749 | enum bpf_access_type t, enum bpf_reg_type *reg_type) |
17a52670 | 750 | { |
f96da094 DB |
751 | struct bpf_insn_access_aux info = { |
752 | .reg_type = *reg_type, | |
753 | }; | |
31fd8581 | 754 | |
13a27dfc JK |
755 | /* for analyzer ctx accesses are already validated and converted */ |
756 | if (env->analyzer_ops) | |
757 | return 0; | |
758 | ||
17a52670 | 759 | if (env->prog->aux->ops->is_valid_access && |
23994631 | 760 | env->prog->aux->ops->is_valid_access(off, size, t, &info)) { |
f96da094 DB |
761 | /* A non zero info.ctx_field_size indicates that this field is a |
762 | * candidate for later verifier transformation to load the whole | |
763 | * field and then apply a mask when accessed with a narrower | |
764 | * access than actual ctx access size. A zero info.ctx_field_size | |
765 | * will only allow for whole field access and rejects any other | |
766 | * type of narrower access. | |
31fd8581 | 767 | */ |
f96da094 | 768 | env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size; |
23994631 | 769 | *reg_type = info.reg_type; |
31fd8581 | 770 | |
32bbe007 AS |
771 | /* remember the offset of last byte accessed in ctx */ |
772 | if (env->prog->aux->max_ctx_offset < off + size) | |
773 | env->prog->aux->max_ctx_offset = off + size; | |
17a52670 | 774 | return 0; |
32bbe007 | 775 | } |
17a52670 AS |
776 | |
777 | verbose("invalid bpf_context access off=%d size=%d\n", off, size); | |
778 | return -EACCES; | |
779 | } | |
780 | ||
4cabc5b1 DB |
781 | static bool __is_pointer_value(bool allow_ptr_leaks, |
782 | const struct bpf_reg_state *reg) | |
1be7f75d | 783 | { |
4cabc5b1 | 784 | if (allow_ptr_leaks) |
1be7f75d AS |
785 | return false; |
786 | ||
4cabc5b1 | 787 | switch (reg->type) { |
1be7f75d AS |
788 | case UNKNOWN_VALUE: |
789 | case CONST_IMM: | |
790 | return false; | |
791 | default: | |
792 | return true; | |
793 | } | |
794 | } | |
795 | ||
4cabc5b1 DB |
796 | static bool is_pointer_value(struct bpf_verifier_env *env, int regno) |
797 | { | |
798 | return __is_pointer_value(env->allow_ptr_leaks, &env->cur_state.regs[regno]); | |
799 | } | |
800 | ||
79adffcd | 801 | static int check_pkt_ptr_alignment(const struct bpf_reg_state *reg, |
d1174416 | 802 | int off, int size, bool strict) |
969bf05e | 803 | { |
e07b98d9 | 804 | int ip_align; |
d1174416 DM |
805 | int reg_off; |
806 | ||
807 | /* Byte size accesses are always allowed. */ | |
808 | if (!strict || size == 1) | |
809 | return 0; | |
810 | ||
811 | reg_off = reg->off; | |
812 | if (reg->id) { | |
813 | if (reg->aux_off_align % size) { | |
814 | verbose("Packet access is only %u byte aligned, %d byte access not allowed\n", | |
815 | reg->aux_off_align, size); | |
816 | return -EACCES; | |
817 | } | |
818 | reg_off += reg->aux_off; | |
969bf05e AS |
819 | } |
820 | ||
e4eda884 DM |
821 | /* For platforms that do not have a Kconfig enabling |
822 | * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of | |
823 | * NET_IP_ALIGN is universally set to '2'. And on platforms | |
824 | * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get | |
825 | * to this code only in strict mode where we want to emulate | |
826 | * the NET_IP_ALIGN==2 checking. Therefore use an | |
827 | * unconditional IP align value of '2'. | |
e07b98d9 | 828 | */ |
e4eda884 | 829 | ip_align = 2; |
e07b98d9 | 830 | if ((ip_align + reg_off + off) % size != 0) { |
969bf05e | 831 | verbose("misaligned packet access off %d+%d+%d size %d\n", |
e07b98d9 | 832 | ip_align, reg_off, off, size); |
969bf05e AS |
833 | return -EACCES; |
834 | } | |
79adffcd | 835 | |
969bf05e AS |
836 | return 0; |
837 | } | |
838 | ||
79adffcd | 839 | static int check_val_ptr_alignment(const struct bpf_reg_state *reg, |
d1174416 | 840 | int size, bool strict) |
79adffcd | 841 | { |
d1174416 | 842 | if (strict && size != 1) { |
79adffcd DB |
843 | verbose("Unknown alignment. Only byte-sized access allowed in value access.\n"); |
844 | return -EACCES; | |
845 | } | |
846 | ||
969bf05e AS |
847 | return 0; |
848 | } | |
849 | ||
e07b98d9 DM |
850 | static int check_ptr_alignment(struct bpf_verifier_env *env, |
851 | const struct bpf_reg_state *reg, | |
79adffcd DB |
852 | int off, int size) |
853 | { | |
e07b98d9 | 854 | bool strict = env->strict_alignment; |
d1174416 | 855 | |
79adffcd DB |
856 | switch (reg->type) { |
857 | case PTR_TO_PACKET: | |
d1174416 | 858 | return check_pkt_ptr_alignment(reg, off, size, strict); |
79adffcd | 859 | case PTR_TO_MAP_VALUE_ADJ: |
d1174416 | 860 | return check_val_ptr_alignment(reg, size, strict); |
79adffcd DB |
861 | default: |
862 | if (off % size != 0) { | |
863 | verbose("misaligned access off %d size %d\n", | |
864 | off, size); | |
865 | return -EACCES; | |
866 | } | |
867 | ||
868 | return 0; | |
869 | } | |
870 | } | |
871 | ||
17a52670 AS |
872 | /* check whether memory at (regno + off) is accessible for t = (read | write) |
873 | * if t==write, value_regno is a register which value is stored into memory | |
874 | * if t==read, value_regno is a register which will receive the value from memory | |
875 | * if t==write && value_regno==-1, some unknown value is stored into memory | |
876 | * if t==read && value_regno==-1, don't care what we read from memory | |
877 | */ | |
31fd8581 | 878 | static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno, int off, |
17a52670 AS |
879 | int bpf_size, enum bpf_access_type t, |
880 | int value_regno) | |
881 | { | |
58e2af8b JK |
882 | struct bpf_verifier_state *state = &env->cur_state; |
883 | struct bpf_reg_state *reg = &state->regs[regno]; | |
17a52670 AS |
884 | int size, err = 0; |
885 | ||
1a0dc1ac AS |
886 | if (reg->type == PTR_TO_STACK) |
887 | off += reg->imm; | |
24b4d2ab | 888 | |
17a52670 AS |
889 | size = bpf_size_to_bytes(bpf_size); |
890 | if (size < 0) | |
891 | return size; | |
892 | ||
e07b98d9 | 893 | err = check_ptr_alignment(env, reg, off, size); |
969bf05e AS |
894 | if (err) |
895 | return err; | |
17a52670 | 896 | |
48461135 JB |
897 | if (reg->type == PTR_TO_MAP_VALUE || |
898 | reg->type == PTR_TO_MAP_VALUE_ADJ) { | |
1be7f75d AS |
899 | if (t == BPF_WRITE && value_regno >= 0 && |
900 | is_pointer_value(env, value_regno)) { | |
901 | verbose("R%d leaks addr into map\n", value_regno); | |
902 | return -EACCES; | |
903 | } | |
48461135 | 904 | |
dbcfe5f7 GB |
905 | if (reg->type == PTR_TO_MAP_VALUE_ADJ) |
906 | err = check_map_access_adj(env, regno, off, size); | |
907 | else | |
908 | err = check_map_access(env, regno, off, size); | |
17a52670 | 909 | if (!err && t == BPF_READ && value_regno >= 0) |
f0318d01 GB |
910 | mark_reg_unknown_value_and_range(state->regs, |
911 | value_regno); | |
17a52670 | 912 | |
1a0dc1ac | 913 | } else if (reg->type == PTR_TO_CTX) { |
19de99f7 AS |
914 | enum bpf_reg_type reg_type = UNKNOWN_VALUE; |
915 | ||
1be7f75d AS |
916 | if (t == BPF_WRITE && value_regno >= 0 && |
917 | is_pointer_value(env, value_regno)) { | |
918 | verbose("R%d leaks addr into ctx\n", value_regno); | |
919 | return -EACCES; | |
920 | } | |
31fd8581 | 921 | err = check_ctx_access(env, insn_idx, off, size, t, ®_type); |
969bf05e | 922 | if (!err && t == BPF_READ && value_regno >= 0) { |
f0318d01 GB |
923 | mark_reg_unknown_value_and_range(state->regs, |
924 | value_regno); | |
1955351d MS |
925 | /* note that reg.[id|off|range] == 0 */ |
926 | state->regs[value_regno].type = reg_type; | |
d1174416 DM |
927 | state->regs[value_regno].aux_off = 0; |
928 | state->regs[value_regno].aux_off_align = 0; | |
969bf05e | 929 | } |
17a52670 | 930 | |
1a0dc1ac | 931 | } else if (reg->type == FRAME_PTR || reg->type == PTR_TO_STACK) { |
17a52670 AS |
932 | if (off >= 0 || off < -MAX_BPF_STACK) { |
933 | verbose("invalid stack off=%d size=%d\n", off, size); | |
934 | return -EACCES; | |
935 | } | |
8726679a AS |
936 | |
937 | if (env->prog->aux->stack_depth < -off) | |
938 | env->prog->aux->stack_depth = -off; | |
939 | ||
1be7f75d AS |
940 | if (t == BPF_WRITE) { |
941 | if (!env->allow_ptr_leaks && | |
942 | state->stack_slot_type[MAX_BPF_STACK + off] == STACK_SPILL && | |
943 | size != BPF_REG_SIZE) { | |
944 | verbose("attempt to corrupt spilled pointer on stack\n"); | |
945 | return -EACCES; | |
946 | } | |
17a52670 | 947 | err = check_stack_write(state, off, size, value_regno); |
1be7f75d | 948 | } else { |
17a52670 | 949 | err = check_stack_read(state, off, size, value_regno); |
1be7f75d | 950 | } |
969bf05e | 951 | } else if (state->regs[regno].type == PTR_TO_PACKET) { |
3a0af8fd | 952 | if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) { |
969bf05e AS |
953 | verbose("cannot write into packet\n"); |
954 | return -EACCES; | |
955 | } | |
4acf6c0b BB |
956 | if (t == BPF_WRITE && value_regno >= 0 && |
957 | is_pointer_value(env, value_regno)) { | |
958 | verbose("R%d leaks addr into packet\n", value_regno); | |
959 | return -EACCES; | |
960 | } | |
969bf05e AS |
961 | err = check_packet_access(env, regno, off, size); |
962 | if (!err && t == BPF_READ && value_regno >= 0) | |
f0318d01 GB |
963 | mark_reg_unknown_value_and_range(state->regs, |
964 | value_regno); | |
17a52670 AS |
965 | } else { |
966 | verbose("R%d invalid mem access '%s'\n", | |
1a0dc1ac | 967 | regno, reg_type_str[reg->type]); |
17a52670 AS |
968 | return -EACCES; |
969 | } | |
969bf05e AS |
970 | |
971 | if (!err && size <= 2 && value_regno >= 0 && env->allow_ptr_leaks && | |
972 | state->regs[value_regno].type == UNKNOWN_VALUE) { | |
973 | /* 1 or 2 byte load zero-extends, determine the number of | |
974 | * zero upper bits. Not doing it fo 4 byte load, since | |
975 | * such values cannot be added to ptr_to_packet anyway. | |
976 | */ | |
977 | state->regs[value_regno].imm = 64 - size * 8; | |
978 | } | |
17a52670 AS |
979 | return err; |
980 | } | |
981 | ||
31fd8581 | 982 | static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_insn *insn) |
17a52670 | 983 | { |
58e2af8b | 984 | struct bpf_reg_state *regs = env->cur_state.regs; |
17a52670 AS |
985 | int err; |
986 | ||
987 | if ((BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) || | |
988 | insn->imm != 0) { | |
989 | verbose("BPF_XADD uses reserved fields\n"); | |
990 | return -EINVAL; | |
991 | } | |
992 | ||
993 | /* check src1 operand */ | |
994 | err = check_reg_arg(regs, insn->src_reg, SRC_OP); | |
995 | if (err) | |
996 | return err; | |
997 | ||
998 | /* check src2 operand */ | |
999 | err = check_reg_arg(regs, insn->dst_reg, SRC_OP); | |
1000 | if (err) | |
1001 | return err; | |
1002 | ||
6bdf6abc DB |
1003 | if (is_pointer_value(env, insn->src_reg)) { |
1004 | verbose("R%d leaks addr into mem\n", insn->src_reg); | |
1005 | return -EACCES; | |
1006 | } | |
1007 | ||
17a52670 | 1008 | /* check whether atomic_add can read the memory */ |
31fd8581 | 1009 | err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off, |
17a52670 AS |
1010 | BPF_SIZE(insn->code), BPF_READ, -1); |
1011 | if (err) | |
1012 | return err; | |
1013 | ||
1014 | /* check whether atomic_add can write into the same memory */ | |
31fd8581 | 1015 | return check_mem_access(env, insn_idx, insn->dst_reg, insn->off, |
17a52670 AS |
1016 | BPF_SIZE(insn->code), BPF_WRITE, -1); |
1017 | } | |
1018 | ||
1019 | /* when register 'regno' is passed into function that will read 'access_size' | |
1020 | * bytes from that pointer, make sure that it's within stack boundary | |
1021 | * and all elements of stack are initialized | |
1022 | */ | |
58e2af8b | 1023 | static int check_stack_boundary(struct bpf_verifier_env *env, int regno, |
435faee1 DB |
1024 | int access_size, bool zero_size_allowed, |
1025 | struct bpf_call_arg_meta *meta) | |
17a52670 | 1026 | { |
58e2af8b JK |
1027 | struct bpf_verifier_state *state = &env->cur_state; |
1028 | struct bpf_reg_state *regs = state->regs; | |
17a52670 AS |
1029 | int off, i; |
1030 | ||
8e2fe1d9 DB |
1031 | if (regs[regno].type != PTR_TO_STACK) { |
1032 | if (zero_size_allowed && access_size == 0 && | |
1033 | regs[regno].type == CONST_IMM && | |
1034 | regs[regno].imm == 0) | |
1035 | return 0; | |
1036 | ||
1037 | verbose("R%d type=%s expected=%s\n", regno, | |
1038 | reg_type_str[regs[regno].type], | |
1039 | reg_type_str[PTR_TO_STACK]); | |
17a52670 | 1040 | return -EACCES; |
8e2fe1d9 | 1041 | } |
17a52670 AS |
1042 | |
1043 | off = regs[regno].imm; | |
1044 | if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 || | |
1045 | access_size <= 0) { | |
1046 | verbose("invalid stack type R%d off=%d access_size=%d\n", | |
1047 | regno, off, access_size); | |
1048 | return -EACCES; | |
1049 | } | |
1050 | ||
8726679a AS |
1051 | if (env->prog->aux->stack_depth < -off) |
1052 | env->prog->aux->stack_depth = -off; | |
1053 | ||
435faee1 DB |
1054 | if (meta && meta->raw_mode) { |
1055 | meta->access_size = access_size; | |
1056 | meta->regno = regno; | |
1057 | return 0; | |
1058 | } | |
1059 | ||
17a52670 | 1060 | for (i = 0; i < access_size; i++) { |
9c399760 | 1061 | if (state->stack_slot_type[MAX_BPF_STACK + off + i] != STACK_MISC) { |
17a52670 AS |
1062 | verbose("invalid indirect read from stack off %d+%d size %d\n", |
1063 | off, i, access_size); | |
1064 | return -EACCES; | |
1065 | } | |
1066 | } | |
1067 | return 0; | |
1068 | } | |
1069 | ||
06c1c049 GB |
1070 | static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, |
1071 | int access_size, bool zero_size_allowed, | |
1072 | struct bpf_call_arg_meta *meta) | |
1073 | { | |
1074 | struct bpf_reg_state *regs = env->cur_state.regs; | |
1075 | ||
1076 | switch (regs[regno].type) { | |
1077 | case PTR_TO_PACKET: | |
1078 | return check_packet_access(env, regno, 0, access_size); | |
1079 | case PTR_TO_MAP_VALUE: | |
1080 | return check_map_access(env, regno, 0, access_size); | |
1081 | case PTR_TO_MAP_VALUE_ADJ: | |
1082 | return check_map_access_adj(env, regno, 0, access_size); | |
1083 | default: /* const_imm|ptr_to_stack or invalid ptr */ | |
1084 | return check_stack_boundary(env, regno, access_size, | |
1085 | zero_size_allowed, meta); | |
1086 | } | |
1087 | } | |
1088 | ||
58e2af8b | 1089 | static int check_func_arg(struct bpf_verifier_env *env, u32 regno, |
33ff9823 DB |
1090 | enum bpf_arg_type arg_type, |
1091 | struct bpf_call_arg_meta *meta) | |
17a52670 | 1092 | { |
58e2af8b | 1093 | struct bpf_reg_state *regs = env->cur_state.regs, *reg = ®s[regno]; |
6841de8b | 1094 | enum bpf_reg_type expected_type, type = reg->type; |
17a52670 AS |
1095 | int err = 0; |
1096 | ||
80f1d68c | 1097 | if (arg_type == ARG_DONTCARE) |
17a52670 AS |
1098 | return 0; |
1099 | ||
6841de8b | 1100 | if (type == NOT_INIT) { |
17a52670 AS |
1101 | verbose("R%d !read_ok\n", regno); |
1102 | return -EACCES; | |
1103 | } | |
1104 | ||
1be7f75d AS |
1105 | if (arg_type == ARG_ANYTHING) { |
1106 | if (is_pointer_value(env, regno)) { | |
1107 | verbose("R%d leaks addr into helper function\n", regno); | |
1108 | return -EACCES; | |
1109 | } | |
80f1d68c | 1110 | return 0; |
1be7f75d | 1111 | } |
80f1d68c | 1112 | |
3a0af8fd TG |
1113 | if (type == PTR_TO_PACKET && |
1114 | !may_access_direct_pkt_data(env, meta, BPF_READ)) { | |
36bbef52 | 1115 | verbose("helper access to the packet is not allowed\n"); |
6841de8b AS |
1116 | return -EACCES; |
1117 | } | |
1118 | ||
8e2fe1d9 | 1119 | if (arg_type == ARG_PTR_TO_MAP_KEY || |
17a52670 AS |
1120 | arg_type == ARG_PTR_TO_MAP_VALUE) { |
1121 | expected_type = PTR_TO_STACK; | |
6841de8b AS |
1122 | if (type != PTR_TO_PACKET && type != expected_type) |
1123 | goto err_type; | |
39f19ebb AS |
1124 | } else if (arg_type == ARG_CONST_SIZE || |
1125 | arg_type == ARG_CONST_SIZE_OR_ZERO) { | |
17a52670 | 1126 | expected_type = CONST_IMM; |
06c1c049 GB |
1127 | /* One exception. Allow UNKNOWN_VALUE registers when the |
1128 | * boundaries are known and don't cause unsafe memory accesses | |
1129 | */ | |
1130 | if (type != UNKNOWN_VALUE && type != expected_type) | |
6841de8b | 1131 | goto err_type; |
17a52670 AS |
1132 | } else if (arg_type == ARG_CONST_MAP_PTR) { |
1133 | expected_type = CONST_PTR_TO_MAP; | |
6841de8b AS |
1134 | if (type != expected_type) |
1135 | goto err_type; | |
608cd71a AS |
1136 | } else if (arg_type == ARG_PTR_TO_CTX) { |
1137 | expected_type = PTR_TO_CTX; | |
6841de8b AS |
1138 | if (type != expected_type) |
1139 | goto err_type; | |
39f19ebb AS |
1140 | } else if (arg_type == ARG_PTR_TO_MEM || |
1141 | arg_type == ARG_PTR_TO_UNINIT_MEM) { | |
8e2fe1d9 DB |
1142 | expected_type = PTR_TO_STACK; |
1143 | /* One exception here. In case function allows for NULL to be | |
1144 | * passed in as argument, it's a CONST_IMM type. Final test | |
1145 | * happens during stack boundary checking. | |
1146 | */ | |
6841de8b AS |
1147 | if (type == CONST_IMM && reg->imm == 0) |
1148 | /* final test in check_stack_boundary() */; | |
5722569b GB |
1149 | else if (type != PTR_TO_PACKET && type != PTR_TO_MAP_VALUE && |
1150 | type != PTR_TO_MAP_VALUE_ADJ && type != expected_type) | |
6841de8b | 1151 | goto err_type; |
39f19ebb | 1152 | meta->raw_mode = arg_type == ARG_PTR_TO_UNINIT_MEM; |
17a52670 AS |
1153 | } else { |
1154 | verbose("unsupported arg_type %d\n", arg_type); | |
1155 | return -EFAULT; | |
1156 | } | |
1157 | ||
17a52670 AS |
1158 | if (arg_type == ARG_CONST_MAP_PTR) { |
1159 | /* bpf_map_xxx(map_ptr) call: remember that map_ptr */ | |
33ff9823 | 1160 | meta->map_ptr = reg->map_ptr; |
17a52670 AS |
1161 | } else if (arg_type == ARG_PTR_TO_MAP_KEY) { |
1162 | /* bpf_map_xxx(..., map_ptr, ..., key) call: | |
1163 | * check that [key, key + map->key_size) are within | |
1164 | * stack limits and initialized | |
1165 | */ | |
33ff9823 | 1166 | if (!meta->map_ptr) { |
17a52670 AS |
1167 | /* in function declaration map_ptr must come before |
1168 | * map_key, so that it's verified and known before | |
1169 | * we have to check map_key here. Otherwise it means | |
1170 | * that kernel subsystem misconfigured verifier | |
1171 | */ | |
1172 | verbose("invalid map_ptr to access map->key\n"); | |
1173 | return -EACCES; | |
1174 | } | |
6841de8b AS |
1175 | if (type == PTR_TO_PACKET) |
1176 | err = check_packet_access(env, regno, 0, | |
1177 | meta->map_ptr->key_size); | |
1178 | else | |
1179 | err = check_stack_boundary(env, regno, | |
1180 | meta->map_ptr->key_size, | |
1181 | false, NULL); | |
17a52670 AS |
1182 | } else if (arg_type == ARG_PTR_TO_MAP_VALUE) { |
1183 | /* bpf_map_xxx(..., map_ptr, ..., value) call: | |
1184 | * check [value, value + map->value_size) validity | |
1185 | */ | |
33ff9823 | 1186 | if (!meta->map_ptr) { |
17a52670 AS |
1187 | /* kernel subsystem misconfigured verifier */ |
1188 | verbose("invalid map_ptr to access map->value\n"); | |
1189 | return -EACCES; | |
1190 | } | |
6841de8b AS |
1191 | if (type == PTR_TO_PACKET) |
1192 | err = check_packet_access(env, regno, 0, | |
1193 | meta->map_ptr->value_size); | |
1194 | else | |
1195 | err = check_stack_boundary(env, regno, | |
1196 | meta->map_ptr->value_size, | |
1197 | false, NULL); | |
39f19ebb AS |
1198 | } else if (arg_type == ARG_CONST_SIZE || |
1199 | arg_type == ARG_CONST_SIZE_OR_ZERO) { | |
1200 | bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO); | |
17a52670 | 1201 | |
17a52670 AS |
1202 | /* bpf_xxx(..., buf, len) call will access 'len' bytes |
1203 | * from stack pointer 'buf'. Check it | |
1204 | * note: regno == len, regno - 1 == buf | |
1205 | */ | |
1206 | if (regno == 0) { | |
1207 | /* kernel subsystem misconfigured verifier */ | |
39f19ebb | 1208 | verbose("ARG_CONST_SIZE cannot be first argument\n"); |
17a52670 AS |
1209 | return -EACCES; |
1210 | } | |
06c1c049 GB |
1211 | |
1212 | /* If the register is UNKNOWN_VALUE, the access check happens | |
1213 | * using its boundaries. Otherwise, just use its imm | |
1214 | */ | |
1215 | if (type == UNKNOWN_VALUE) { | |
1216 | /* For unprivileged variable accesses, disable raw | |
1217 | * mode so that the program is required to | |
1218 | * initialize all the memory that the helper could | |
1219 | * just partially fill up. | |
1220 | */ | |
1221 | meta = NULL; | |
1222 | ||
1223 | if (reg->min_value < 0) { | |
1224 | verbose("R%d min value is negative, either use unsigned or 'var &= const'\n", | |
1225 | regno); | |
1226 | return -EACCES; | |
1227 | } | |
1228 | ||
1229 | if (reg->min_value == 0) { | |
1230 | err = check_helper_mem_access(env, regno - 1, 0, | |
1231 | zero_size_allowed, | |
1232 | meta); | |
1233 | if (err) | |
1234 | return err; | |
1235 | } | |
1236 | ||
1237 | if (reg->max_value == BPF_REGISTER_MAX_RANGE) { | |
1238 | verbose("R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n", | |
1239 | regno); | |
1240 | return -EACCES; | |
1241 | } | |
1242 | err = check_helper_mem_access(env, regno - 1, | |
1243 | reg->max_value, | |
1244 | zero_size_allowed, meta); | |
1245 | if (err) | |
1246 | return err; | |
1247 | } else { | |
1248 | /* register is CONST_IMM */ | |
1249 | err = check_helper_mem_access(env, regno - 1, reg->imm, | |
1250 | zero_size_allowed, meta); | |
1251 | } | |
17a52670 AS |
1252 | } |
1253 | ||
1254 | return err; | |
6841de8b AS |
1255 | err_type: |
1256 | verbose("R%d type=%s expected=%s\n", regno, | |
1257 | reg_type_str[type], reg_type_str[expected_type]); | |
1258 | return -EACCES; | |
17a52670 AS |
1259 | } |
1260 | ||
35578d79 KX |
1261 | static int check_map_func_compatibility(struct bpf_map *map, int func_id) |
1262 | { | |
35578d79 KX |
1263 | if (!map) |
1264 | return 0; | |
1265 | ||
6aff67c8 AS |
1266 | /* We need a two way check, first is from map perspective ... */ |
1267 | switch (map->map_type) { | |
1268 | case BPF_MAP_TYPE_PROG_ARRAY: | |
1269 | if (func_id != BPF_FUNC_tail_call) | |
1270 | goto error; | |
1271 | break; | |
1272 | case BPF_MAP_TYPE_PERF_EVENT_ARRAY: | |
1273 | if (func_id != BPF_FUNC_perf_event_read && | |
1274 | func_id != BPF_FUNC_perf_event_output) | |
1275 | goto error; | |
1276 | break; | |
1277 | case BPF_MAP_TYPE_STACK_TRACE: | |
1278 | if (func_id != BPF_FUNC_get_stackid) | |
1279 | goto error; | |
1280 | break; | |
4ed8ec52 | 1281 | case BPF_MAP_TYPE_CGROUP_ARRAY: |
60747ef4 | 1282 | if (func_id != BPF_FUNC_skb_under_cgroup && |
60d20f91 | 1283 | func_id != BPF_FUNC_current_task_under_cgroup) |
4a482f34 MKL |
1284 | goto error; |
1285 | break; | |
56f668df | 1286 | case BPF_MAP_TYPE_ARRAY_OF_MAPS: |
bcc6b1b7 | 1287 | case BPF_MAP_TYPE_HASH_OF_MAPS: |
56f668df MKL |
1288 | if (func_id != BPF_FUNC_map_lookup_elem) |
1289 | goto error; | |
6aff67c8 AS |
1290 | default: |
1291 | break; | |
1292 | } | |
1293 | ||
1294 | /* ... and second from the function itself. */ | |
1295 | switch (func_id) { | |
1296 | case BPF_FUNC_tail_call: | |
1297 | if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) | |
1298 | goto error; | |
1299 | break; | |
1300 | case BPF_FUNC_perf_event_read: | |
1301 | case BPF_FUNC_perf_event_output: | |
1302 | if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) | |
1303 | goto error; | |
1304 | break; | |
1305 | case BPF_FUNC_get_stackid: | |
1306 | if (map->map_type != BPF_MAP_TYPE_STACK_TRACE) | |
1307 | goto error; | |
1308 | break; | |
60d20f91 | 1309 | case BPF_FUNC_current_task_under_cgroup: |
747ea55e | 1310 | case BPF_FUNC_skb_under_cgroup: |
4a482f34 MKL |
1311 | if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY) |
1312 | goto error; | |
1313 | break; | |
6aff67c8 AS |
1314 | default: |
1315 | break; | |
35578d79 KX |
1316 | } |
1317 | ||
1318 | return 0; | |
6aff67c8 | 1319 | error: |
ebb676da TG |
1320 | verbose("cannot pass map_type %d into func %s#%d\n", |
1321 | map->map_type, func_id_name(func_id), func_id); | |
6aff67c8 | 1322 | return -EINVAL; |
35578d79 KX |
1323 | } |
1324 | ||
435faee1 DB |
1325 | static int check_raw_mode(const struct bpf_func_proto *fn) |
1326 | { | |
1327 | int count = 0; | |
1328 | ||
39f19ebb | 1329 | if (fn->arg1_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 1330 | count++; |
39f19ebb | 1331 | if (fn->arg2_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 1332 | count++; |
39f19ebb | 1333 | if (fn->arg3_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 1334 | count++; |
39f19ebb | 1335 | if (fn->arg4_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 | 1336 | count++; |
39f19ebb | 1337 | if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM) |
435faee1 DB |
1338 | count++; |
1339 | ||
1340 | return count > 1 ? -EINVAL : 0; | |
1341 | } | |
1342 | ||
58e2af8b | 1343 | static void clear_all_pkt_pointers(struct bpf_verifier_env *env) |
969bf05e | 1344 | { |
58e2af8b JK |
1345 | struct bpf_verifier_state *state = &env->cur_state; |
1346 | struct bpf_reg_state *regs = state->regs, *reg; | |
969bf05e AS |
1347 | int i; |
1348 | ||
1349 | for (i = 0; i < MAX_BPF_REG; i++) | |
1350 | if (regs[i].type == PTR_TO_PACKET || | |
1351 | regs[i].type == PTR_TO_PACKET_END) | |
1352 | mark_reg_unknown_value(regs, i); | |
1353 | ||
1354 | for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) { | |
1355 | if (state->stack_slot_type[i] != STACK_SPILL) | |
1356 | continue; | |
1357 | reg = &state->spilled_regs[i / BPF_REG_SIZE]; | |
1358 | if (reg->type != PTR_TO_PACKET && | |
1359 | reg->type != PTR_TO_PACKET_END) | |
1360 | continue; | |
36e24c00 DB |
1361 | __mark_reg_unknown_value(state->spilled_regs, |
1362 | i / BPF_REG_SIZE); | |
969bf05e AS |
1363 | } |
1364 | } | |
1365 | ||
81ed18ab | 1366 | static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx) |
17a52670 | 1367 | { |
58e2af8b | 1368 | struct bpf_verifier_state *state = &env->cur_state; |
17a52670 | 1369 | const struct bpf_func_proto *fn = NULL; |
58e2af8b | 1370 | struct bpf_reg_state *regs = state->regs; |
33ff9823 | 1371 | struct bpf_call_arg_meta meta; |
969bf05e | 1372 | bool changes_data; |
17a52670 AS |
1373 | int i, err; |
1374 | ||
1375 | /* find function prototype */ | |
1376 | if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) { | |
ebb676da | 1377 | verbose("invalid func %s#%d\n", func_id_name(func_id), func_id); |
17a52670 AS |
1378 | return -EINVAL; |
1379 | } | |
1380 | ||
1381 | if (env->prog->aux->ops->get_func_proto) | |
1382 | fn = env->prog->aux->ops->get_func_proto(func_id); | |
1383 | ||
1384 | if (!fn) { | |
ebb676da | 1385 | verbose("unknown func %s#%d\n", func_id_name(func_id), func_id); |
17a52670 AS |
1386 | return -EINVAL; |
1387 | } | |
1388 | ||
1389 | /* eBPF programs must be GPL compatible to use GPL-ed functions */ | |
24701ece | 1390 | if (!env->prog->gpl_compatible && fn->gpl_only) { |
17a52670 AS |
1391 | verbose("cannot call GPL only function from proprietary program\n"); |
1392 | return -EINVAL; | |
1393 | } | |
1394 | ||
17bedab2 | 1395 | changes_data = bpf_helper_changes_pkt_data(fn->func); |
969bf05e | 1396 | |
33ff9823 | 1397 | memset(&meta, 0, sizeof(meta)); |
36bbef52 | 1398 | meta.pkt_access = fn->pkt_access; |
33ff9823 | 1399 | |
435faee1 DB |
1400 | /* We only support one arg being in raw mode at the moment, which |
1401 | * is sufficient for the helper functions we have right now. | |
1402 | */ | |
1403 | err = check_raw_mode(fn); | |
1404 | if (err) { | |
ebb676da TG |
1405 | verbose("kernel subsystem misconfigured func %s#%d\n", |
1406 | func_id_name(func_id), func_id); | |
435faee1 DB |
1407 | return err; |
1408 | } | |
1409 | ||
17a52670 | 1410 | /* check args */ |
33ff9823 | 1411 | err = check_func_arg(env, BPF_REG_1, fn->arg1_type, &meta); |
17a52670 AS |
1412 | if (err) |
1413 | return err; | |
33ff9823 | 1414 | err = check_func_arg(env, BPF_REG_2, fn->arg2_type, &meta); |
17a52670 AS |
1415 | if (err) |
1416 | return err; | |
33ff9823 | 1417 | err = check_func_arg(env, BPF_REG_3, fn->arg3_type, &meta); |
17a52670 AS |
1418 | if (err) |
1419 | return err; | |
33ff9823 | 1420 | err = check_func_arg(env, BPF_REG_4, fn->arg4_type, &meta); |
17a52670 AS |
1421 | if (err) |
1422 | return err; | |
33ff9823 | 1423 | err = check_func_arg(env, BPF_REG_5, fn->arg5_type, &meta); |
17a52670 AS |
1424 | if (err) |
1425 | return err; | |
1426 | ||
435faee1 DB |
1427 | /* Mark slots with STACK_MISC in case of raw mode, stack offset |
1428 | * is inferred from register state. | |
1429 | */ | |
1430 | for (i = 0; i < meta.access_size; i++) { | |
31fd8581 | 1431 | err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B, BPF_WRITE, -1); |
435faee1 DB |
1432 | if (err) |
1433 | return err; | |
1434 | } | |
1435 | ||
17a52670 | 1436 | /* reset caller saved regs */ |
a9789ef9 DB |
1437 | for (i = 0; i < CALLER_SAVED_REGS; i++) |
1438 | mark_reg_not_init(regs, caller_saved[i]); | |
17a52670 AS |
1439 | |
1440 | /* update return register */ | |
1441 | if (fn->ret_type == RET_INTEGER) { | |
1442 | regs[BPF_REG_0].type = UNKNOWN_VALUE; | |
1443 | } else if (fn->ret_type == RET_VOID) { | |
1444 | regs[BPF_REG_0].type = NOT_INIT; | |
1445 | } else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL) { | |
fad73a1a MKL |
1446 | struct bpf_insn_aux_data *insn_aux; |
1447 | ||
17a52670 | 1448 | regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL; |
48461135 | 1449 | regs[BPF_REG_0].max_value = regs[BPF_REG_0].min_value = 0; |
17a52670 AS |
1450 | /* remember map_ptr, so that check_map_access() |
1451 | * can check 'value_size' boundary of memory access | |
1452 | * to map element returned from bpf_map_lookup_elem() | |
1453 | */ | |
33ff9823 | 1454 | if (meta.map_ptr == NULL) { |
17a52670 AS |
1455 | verbose("kernel subsystem misconfigured verifier\n"); |
1456 | return -EINVAL; | |
1457 | } | |
33ff9823 | 1458 | regs[BPF_REG_0].map_ptr = meta.map_ptr; |
57a09bf0 | 1459 | regs[BPF_REG_0].id = ++env->id_gen; |
fad73a1a MKL |
1460 | insn_aux = &env->insn_aux_data[insn_idx]; |
1461 | if (!insn_aux->map_ptr) | |
1462 | insn_aux->map_ptr = meta.map_ptr; | |
1463 | else if (insn_aux->map_ptr != meta.map_ptr) | |
1464 | insn_aux->map_ptr = BPF_MAP_PTR_POISON; | |
17a52670 | 1465 | } else { |
ebb676da TG |
1466 | verbose("unknown return type %d of func %s#%d\n", |
1467 | fn->ret_type, func_id_name(func_id), func_id); | |
17a52670 AS |
1468 | return -EINVAL; |
1469 | } | |
04fd61ab | 1470 | |
33ff9823 | 1471 | err = check_map_func_compatibility(meta.map_ptr, func_id); |
35578d79 KX |
1472 | if (err) |
1473 | return err; | |
04fd61ab | 1474 | |
969bf05e AS |
1475 | if (changes_data) |
1476 | clear_all_pkt_pointers(env); | |
1477 | return 0; | |
1478 | } | |
1479 | ||
58e2af8b JK |
1480 | static int check_packet_ptr_add(struct bpf_verifier_env *env, |
1481 | struct bpf_insn *insn) | |
969bf05e | 1482 | { |
58e2af8b JK |
1483 | struct bpf_reg_state *regs = env->cur_state.regs; |
1484 | struct bpf_reg_state *dst_reg = ®s[insn->dst_reg]; | |
1485 | struct bpf_reg_state *src_reg = ®s[insn->src_reg]; | |
1486 | struct bpf_reg_state tmp_reg; | |
969bf05e AS |
1487 | s32 imm; |
1488 | ||
1489 | if (BPF_SRC(insn->code) == BPF_K) { | |
1490 | /* pkt_ptr += imm */ | |
1491 | imm = insn->imm; | |
1492 | ||
1493 | add_imm: | |
63dfef75 | 1494 | if (imm < 0) { |
969bf05e AS |
1495 | verbose("addition of negative constant to packet pointer is not allowed\n"); |
1496 | return -EACCES; | |
1497 | } | |
1498 | if (imm >= MAX_PACKET_OFF || | |
1499 | imm + dst_reg->off >= MAX_PACKET_OFF) { | |
1500 | verbose("constant %d is too large to add to packet pointer\n", | |
1501 | imm); | |
1502 | return -EACCES; | |
1503 | } | |
1504 | /* a constant was added to pkt_ptr. | |
1505 | * Remember it while keeping the same 'id' | |
1506 | */ | |
1507 | dst_reg->off += imm; | |
1508 | } else { | |
d1174416 DM |
1509 | bool had_id; |
1510 | ||
1b9b69ec AS |
1511 | if (src_reg->type == PTR_TO_PACKET) { |
1512 | /* R6=pkt(id=0,off=0,r=62) R7=imm22; r7 += r6 */ | |
1513 | tmp_reg = *dst_reg; /* save r7 state */ | |
1514 | *dst_reg = *src_reg; /* copy pkt_ptr state r6 into r7 */ | |
1515 | src_reg = &tmp_reg; /* pretend it's src_reg state */ | |
1516 | /* if the checks below reject it, the copy won't matter, | |
1517 | * since we're rejecting the whole program. If all ok, | |
1518 | * then imm22 state will be added to r7 | |
1519 | * and r7 will be pkt(id=0,off=22,r=62) while | |
1520 | * r6 will stay as pkt(id=0,off=0,r=62) | |
1521 | */ | |
1522 | } | |
1523 | ||
969bf05e AS |
1524 | if (src_reg->type == CONST_IMM) { |
1525 | /* pkt_ptr += reg where reg is known constant */ | |
1526 | imm = src_reg->imm; | |
1527 | goto add_imm; | |
1528 | } | |
1529 | /* disallow pkt_ptr += reg | |
1530 | * if reg is not uknown_value with guaranteed zero upper bits | |
1531 | * otherwise pkt_ptr may overflow and addition will become | |
1532 | * subtraction which is not allowed | |
1533 | */ | |
1534 | if (src_reg->type != UNKNOWN_VALUE) { | |
1535 | verbose("cannot add '%s' to ptr_to_packet\n", | |
1536 | reg_type_str[src_reg->type]); | |
1537 | return -EACCES; | |
1538 | } | |
1539 | if (src_reg->imm < 48) { | |
1540 | verbose("cannot add integer value with %lld upper zero bits to ptr_to_packet\n", | |
1541 | src_reg->imm); | |
1542 | return -EACCES; | |
1543 | } | |
d1174416 DM |
1544 | |
1545 | had_id = (dst_reg->id != 0); | |
1546 | ||
969bf05e AS |
1547 | /* dst_reg stays as pkt_ptr type and since some positive |
1548 | * integer value was added to the pointer, increment its 'id' | |
1549 | */ | |
1f415a74 | 1550 | dst_reg->id = ++env->id_gen; |
969bf05e | 1551 | |
d1174416 | 1552 | /* something was added to pkt_ptr, set range to zero */ |
6832a333 | 1553 | dst_reg->aux_off += dst_reg->off; |
969bf05e AS |
1554 | dst_reg->off = 0; |
1555 | dst_reg->range = 0; | |
d1174416 DM |
1556 | if (had_id) |
1557 | dst_reg->aux_off_align = min(dst_reg->aux_off_align, | |
1558 | src_reg->min_align); | |
1559 | else | |
1560 | dst_reg->aux_off_align = src_reg->min_align; | |
969bf05e AS |
1561 | } |
1562 | return 0; | |
1563 | } | |
1564 | ||
58e2af8b | 1565 | static int evaluate_reg_alu(struct bpf_verifier_env *env, struct bpf_insn *insn) |
969bf05e | 1566 | { |
58e2af8b JK |
1567 | struct bpf_reg_state *regs = env->cur_state.regs; |
1568 | struct bpf_reg_state *dst_reg = ®s[insn->dst_reg]; | |
969bf05e AS |
1569 | u8 opcode = BPF_OP(insn->code); |
1570 | s64 imm_log2; | |
1571 | ||
1572 | /* for type == UNKNOWN_VALUE: | |
1573 | * imm > 0 -> number of zero upper bits | |
1574 | * imm == 0 -> don't track which is the same as all bits can be non-zero | |
1575 | */ | |
1576 | ||
1577 | if (BPF_SRC(insn->code) == BPF_X) { | |
58e2af8b | 1578 | struct bpf_reg_state *src_reg = ®s[insn->src_reg]; |
969bf05e AS |
1579 | |
1580 | if (src_reg->type == UNKNOWN_VALUE && src_reg->imm > 0 && | |
1581 | dst_reg->imm && opcode == BPF_ADD) { | |
1582 | /* dreg += sreg | |
1583 | * where both have zero upper bits. Adding them | |
1584 | * can only result making one more bit non-zero | |
1585 | * in the larger value. | |
1586 | * Ex. 0xffff (imm=48) + 1 (imm=63) = 0x10000 (imm=47) | |
1587 | * 0xffff (imm=48) + 0xffff = 0x1fffe (imm=47) | |
1588 | */ | |
1589 | dst_reg->imm = min(dst_reg->imm, src_reg->imm); | |
1590 | dst_reg->imm--; | |
1591 | return 0; | |
1592 | } | |
1593 | if (src_reg->type == CONST_IMM && src_reg->imm > 0 && | |
1594 | dst_reg->imm && opcode == BPF_ADD) { | |
1595 | /* dreg += sreg | |
1596 | * where dreg has zero upper bits and sreg is const. | |
1597 | * Adding them can only result making one more bit | |
1598 | * non-zero in the larger value. | |
1599 | */ | |
1600 | imm_log2 = __ilog2_u64((long long)src_reg->imm); | |
1601 | dst_reg->imm = min(dst_reg->imm, 63 - imm_log2); | |
1602 | dst_reg->imm--; | |
1603 | return 0; | |
1604 | } | |
1605 | /* all other cases non supported yet, just mark dst_reg */ | |
1606 | dst_reg->imm = 0; | |
1607 | return 0; | |
1608 | } | |
1609 | ||
1610 | /* sign extend 32-bit imm into 64-bit to make sure that | |
1611 | * negative values occupy bit 63. Note ilog2() would have | |
1612 | * been incorrect, since sizeof(insn->imm) == 4 | |
1613 | */ | |
1614 | imm_log2 = __ilog2_u64((long long)insn->imm); | |
1615 | ||
1616 | if (dst_reg->imm && opcode == BPF_LSH) { | |
1617 | /* reg <<= imm | |
1618 | * if reg was a result of 2 byte load, then its imm == 48 | |
1619 | * which means that upper 48 bits are zero and shifting this reg | |
1620 | * left by 4 would mean that upper 44 bits are still zero | |
1621 | */ | |
1622 | dst_reg->imm -= insn->imm; | |
1623 | } else if (dst_reg->imm && opcode == BPF_MUL) { | |
1624 | /* reg *= imm | |
1625 | * if multiplying by 14 subtract 4 | |
1626 | * This is conservative calculation of upper zero bits. | |
1627 | * It's not trying to special case insn->imm == 1 or 0 cases | |
1628 | */ | |
1629 | dst_reg->imm -= imm_log2 + 1; | |
1630 | } else if (opcode == BPF_AND) { | |
1631 | /* reg &= imm */ | |
1632 | dst_reg->imm = 63 - imm_log2; | |
1633 | } else if (dst_reg->imm && opcode == BPF_ADD) { | |
1634 | /* reg += imm */ | |
1635 | dst_reg->imm = min(dst_reg->imm, 63 - imm_log2); | |
1636 | dst_reg->imm--; | |
1637 | } else if (opcode == BPF_RSH) { | |
1638 | /* reg >>= imm | |
1639 | * which means that after right shift, upper bits will be zero | |
1640 | * note that verifier already checked that | |
1641 | * 0 <= imm < 64 for shift insn | |
1642 | */ | |
1643 | dst_reg->imm += insn->imm; | |
1644 | if (unlikely(dst_reg->imm > 64)) | |
1645 | /* some dumb code did: | |
1646 | * r2 = *(u32 *)mem; | |
1647 | * r2 >>= 32; | |
1648 | * and all bits are zero now */ | |
1649 | dst_reg->imm = 64; | |
1650 | } else { | |
1651 | /* all other alu ops, means that we don't know what will | |
1652 | * happen to the value, mark it with unknown number of zero bits | |
1653 | */ | |
1654 | dst_reg->imm = 0; | |
1655 | } | |
1656 | ||
1657 | if (dst_reg->imm < 0) { | |
1658 | /* all 64 bits of the register can contain non-zero bits | |
1659 | * and such value cannot be added to ptr_to_packet, since it | |
1660 | * may overflow, mark it as unknown to avoid further eval | |
1661 | */ | |
1662 | dst_reg->imm = 0; | |
1663 | } | |
1664 | return 0; | |
1665 | } | |
1666 | ||
43188702 JF |
1667 | static int evaluate_reg_imm_alu_unknown(struct bpf_verifier_env *env, |
1668 | struct bpf_insn *insn) | |
1669 | { | |
1670 | struct bpf_reg_state *regs = env->cur_state.regs; | |
1671 | struct bpf_reg_state *dst_reg = ®s[insn->dst_reg]; | |
1672 | struct bpf_reg_state *src_reg = ®s[insn->src_reg]; | |
1673 | u8 opcode = BPF_OP(insn->code); | |
1674 | s64 imm_log2 = __ilog2_u64((long long)dst_reg->imm); | |
1675 | ||
1676 | /* BPF_X code with src_reg->type UNKNOWN_VALUE here. */ | |
1677 | if (src_reg->imm > 0 && dst_reg->imm) { | |
1678 | switch (opcode) { | |
1679 | case BPF_ADD: | |
1680 | /* dreg += sreg | |
1681 | * where both have zero upper bits. Adding them | |
1682 | * can only result making one more bit non-zero | |
1683 | * in the larger value. | |
1684 | * Ex. 0xffff (imm=48) + 1 (imm=63) = 0x10000 (imm=47) | |
1685 | * 0xffff (imm=48) + 0xffff = 0x1fffe (imm=47) | |
1686 | */ | |
1687 | dst_reg->imm = min(src_reg->imm, 63 - imm_log2); | |
1688 | dst_reg->imm--; | |
1689 | break; | |
1690 | case BPF_AND: | |
1691 | /* dreg &= sreg | |
1692 | * AND can not extend zero bits only shrink | |
1693 | * Ex. 0x00..00ffffff | |
1694 | * & 0x0f..ffffffff | |
1695 | * ---------------- | |
1696 | * 0x00..00ffffff | |
1697 | */ | |
1698 | dst_reg->imm = max(src_reg->imm, 63 - imm_log2); | |
1699 | break; | |
1700 | case BPF_OR: | |
1701 | /* dreg |= sreg | |
1702 | * OR can only extend zero bits | |
1703 | * Ex. 0x00..00ffffff | |
1704 | * | 0x0f..ffffffff | |
1705 | * ---------------- | |
1706 | * 0x0f..00ffffff | |
1707 | */ | |
1708 | dst_reg->imm = min(src_reg->imm, 63 - imm_log2); | |
1709 | break; | |
1710 | case BPF_SUB: | |
1711 | case BPF_MUL: | |
1712 | case BPF_RSH: | |
1713 | case BPF_LSH: | |
1714 | /* These may be flushed out later */ | |
1715 | default: | |
1716 | mark_reg_unknown_value(regs, insn->dst_reg); | |
1717 | } | |
1718 | } else { | |
1719 | mark_reg_unknown_value(regs, insn->dst_reg); | |
1720 | } | |
1721 | ||
1722 | dst_reg->type = UNKNOWN_VALUE; | |
1723 | return 0; | |
1724 | } | |
1725 | ||
58e2af8b JK |
1726 | static int evaluate_reg_imm_alu(struct bpf_verifier_env *env, |
1727 | struct bpf_insn *insn) | |
969bf05e | 1728 | { |
58e2af8b JK |
1729 | struct bpf_reg_state *regs = env->cur_state.regs; |
1730 | struct bpf_reg_state *dst_reg = ®s[insn->dst_reg]; | |
1731 | struct bpf_reg_state *src_reg = ®s[insn->src_reg]; | |
969bf05e | 1732 | u8 opcode = BPF_OP(insn->code); |
3fadc801 | 1733 | u64 dst_imm = dst_reg->imm; |
969bf05e | 1734 | |
43188702 JF |
1735 | if (BPF_SRC(insn->code) == BPF_X && src_reg->type == UNKNOWN_VALUE) |
1736 | return evaluate_reg_imm_alu_unknown(env, insn); | |
1737 | ||
3fadc801 DB |
1738 | /* dst_reg->type == CONST_IMM here. Simulate execution of insns |
1739 | * containing ALU ops. Don't care about overflow or negative | |
1740 | * values, just add/sub/... them; registers are in u64. | |
969bf05e | 1741 | */ |
3fadc801 DB |
1742 | if (opcode == BPF_ADD && BPF_SRC(insn->code) == BPF_K) { |
1743 | dst_imm += insn->imm; | |
1744 | } else if (opcode == BPF_ADD && BPF_SRC(insn->code) == BPF_X && | |
1745 | src_reg->type == CONST_IMM) { | |
1746 | dst_imm += src_reg->imm; | |
1747 | } else if (opcode == BPF_SUB && BPF_SRC(insn->code) == BPF_K) { | |
1748 | dst_imm -= insn->imm; | |
1749 | } else if (opcode == BPF_SUB && BPF_SRC(insn->code) == BPF_X && | |
1750 | src_reg->type == CONST_IMM) { | |
1751 | dst_imm -= src_reg->imm; | |
1752 | } else if (opcode == BPF_MUL && BPF_SRC(insn->code) == BPF_K) { | |
1753 | dst_imm *= insn->imm; | |
1754 | } else if (opcode == BPF_MUL && BPF_SRC(insn->code) == BPF_X && | |
1755 | src_reg->type == CONST_IMM) { | |
1756 | dst_imm *= src_reg->imm; | |
1757 | } else if (opcode == BPF_OR && BPF_SRC(insn->code) == BPF_K) { | |
1758 | dst_imm |= insn->imm; | |
1759 | } else if (opcode == BPF_OR && BPF_SRC(insn->code) == BPF_X && | |
1760 | src_reg->type == CONST_IMM) { | |
1761 | dst_imm |= src_reg->imm; | |
1762 | } else if (opcode == BPF_AND && BPF_SRC(insn->code) == BPF_K) { | |
1763 | dst_imm &= insn->imm; | |
1764 | } else if (opcode == BPF_AND && BPF_SRC(insn->code) == BPF_X && | |
1765 | src_reg->type == CONST_IMM) { | |
1766 | dst_imm &= src_reg->imm; | |
1767 | } else if (opcode == BPF_RSH && BPF_SRC(insn->code) == BPF_K) { | |
1768 | dst_imm >>= insn->imm; | |
1769 | } else if (opcode == BPF_RSH && BPF_SRC(insn->code) == BPF_X && | |
1770 | src_reg->type == CONST_IMM) { | |
1771 | dst_imm >>= src_reg->imm; | |
1772 | } else if (opcode == BPF_LSH && BPF_SRC(insn->code) == BPF_K) { | |
1773 | dst_imm <<= insn->imm; | |
1774 | } else if (opcode == BPF_LSH && BPF_SRC(insn->code) == BPF_X && | |
1775 | src_reg->type == CONST_IMM) { | |
1776 | dst_imm <<= src_reg->imm; | |
1777 | } else { | |
969bf05e | 1778 | mark_reg_unknown_value(regs, insn->dst_reg); |
3fadc801 DB |
1779 | goto out; |
1780 | } | |
1781 | ||
1782 | dst_reg->imm = dst_imm; | |
1783 | out: | |
17a52670 AS |
1784 | return 0; |
1785 | } | |
1786 | ||
48461135 JB |
1787 | static void check_reg_overflow(struct bpf_reg_state *reg) |
1788 | { | |
1789 | if (reg->max_value > BPF_REGISTER_MAX_RANGE) | |
1790 | reg->max_value = BPF_REGISTER_MAX_RANGE; | |
f23cc643 JB |
1791 | if (reg->min_value < BPF_REGISTER_MIN_RANGE || |
1792 | reg->min_value > BPF_REGISTER_MAX_RANGE) | |
48461135 JB |
1793 | reg->min_value = BPF_REGISTER_MIN_RANGE; |
1794 | } | |
1795 | ||
d1174416 DM |
1796 | static u32 calc_align(u32 imm) |
1797 | { | |
1798 | if (!imm) | |
1799 | return 1U << 31; | |
1800 | return imm - ((imm - 1) & imm); | |
1801 | } | |
1802 | ||
48461135 JB |
1803 | static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, |
1804 | struct bpf_insn *insn) | |
1805 | { | |
1806 | struct bpf_reg_state *regs = env->cur_state.regs, *dst_reg; | |
f23cc643 JB |
1807 | s64 min_val = BPF_REGISTER_MIN_RANGE; |
1808 | u64 max_val = BPF_REGISTER_MAX_RANGE; | |
48461135 | 1809 | u8 opcode = BPF_OP(insn->code); |
d1174416 | 1810 | u32 dst_align, src_align; |
48461135 JB |
1811 | |
1812 | dst_reg = ®s[insn->dst_reg]; | |
d1174416 | 1813 | src_align = 0; |
48461135 JB |
1814 | if (BPF_SRC(insn->code) == BPF_X) { |
1815 | check_reg_overflow(®s[insn->src_reg]); | |
1816 | min_val = regs[insn->src_reg].min_value; | |
1817 | max_val = regs[insn->src_reg].max_value; | |
1818 | ||
1819 | /* If the source register is a random pointer then the | |
1820 | * min_value/max_value values represent the range of the known | |
1821 | * accesses into that value, not the actual min/max value of the | |
1822 | * register itself. In this case we have to reset the reg range | |
1823 | * values so we know it is not safe to look at. | |
1824 | */ | |
1825 | if (regs[insn->src_reg].type != CONST_IMM && | |
1826 | regs[insn->src_reg].type != UNKNOWN_VALUE) { | |
1827 | min_val = BPF_REGISTER_MIN_RANGE; | |
1828 | max_val = BPF_REGISTER_MAX_RANGE; | |
d1174416 DM |
1829 | src_align = 0; |
1830 | } else { | |
1831 | src_align = regs[insn->src_reg].min_align; | |
48461135 JB |
1832 | } |
1833 | } else if (insn->imm < BPF_REGISTER_MAX_RANGE && | |
1834 | (s64)insn->imm > BPF_REGISTER_MIN_RANGE) { | |
1835 | min_val = max_val = insn->imm; | |
d1174416 | 1836 | src_align = calc_align(insn->imm); |
48461135 JB |
1837 | } |
1838 | ||
d1174416 DM |
1839 | dst_align = dst_reg->min_align; |
1840 | ||
48461135 | 1841 | /* We don't know anything about what was done to this register, mark it |
4cabc5b1 DB |
1842 | * as unknown. Also, if both derived bounds came from signed/unsigned |
1843 | * mixed compares and one side is unbounded, we cannot really do anything | |
1844 | * with them as boundaries cannot be trusted. Thus, arithmetic of two | |
1845 | * regs of such kind will get invalidated bounds on the dst side. | |
48461135 | 1846 | */ |
4cabc5b1 DB |
1847 | if ((min_val == BPF_REGISTER_MIN_RANGE && |
1848 | max_val == BPF_REGISTER_MAX_RANGE) || | |
1849 | (BPF_SRC(insn->code) == BPF_X && | |
1850 | ((min_val != BPF_REGISTER_MIN_RANGE && | |
1851 | max_val == BPF_REGISTER_MAX_RANGE) || | |
1852 | (min_val == BPF_REGISTER_MIN_RANGE && | |
1853 | max_val != BPF_REGISTER_MAX_RANGE) || | |
1854 | (dst_reg->min_value != BPF_REGISTER_MIN_RANGE && | |
1855 | dst_reg->max_value == BPF_REGISTER_MAX_RANGE) || | |
1856 | (dst_reg->min_value == BPF_REGISTER_MIN_RANGE && | |
1857 | dst_reg->max_value != BPF_REGISTER_MAX_RANGE)) && | |
1858 | regs[insn->dst_reg].value_from_signed != | |
1859 | regs[insn->src_reg].value_from_signed)) { | |
48461135 JB |
1860 | reset_reg_range_values(regs, insn->dst_reg); |
1861 | return; | |
1862 | } | |
1863 | ||
f23cc643 JB |
1864 | /* If one of our values was at the end of our ranges then we can't just |
1865 | * do our normal operations to the register, we need to set the values | |
1866 | * to the min/max since they are undefined. | |
1867 | */ | |
1868 | if (min_val == BPF_REGISTER_MIN_RANGE) | |
1869 | dst_reg->min_value = BPF_REGISTER_MIN_RANGE; | |
1870 | if (max_val == BPF_REGISTER_MAX_RANGE) | |
1871 | dst_reg->max_value = BPF_REGISTER_MAX_RANGE; | |
1872 | ||
48461135 JB |
1873 | switch (opcode) { |
1874 | case BPF_ADD: | |
f23cc643 JB |
1875 | if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) |
1876 | dst_reg->min_value += min_val; | |
1877 | if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) | |
1878 | dst_reg->max_value += max_val; | |
d1174416 | 1879 | dst_reg->min_align = min(src_align, dst_align); |
48461135 JB |
1880 | break; |
1881 | case BPF_SUB: | |
f23cc643 JB |
1882 | if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) |
1883 | dst_reg->min_value -= min_val; | |
1884 | if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) | |
1885 | dst_reg->max_value -= max_val; | |
d1174416 | 1886 | dst_reg->min_align = min(src_align, dst_align); |
48461135 JB |
1887 | break; |
1888 | case BPF_MUL: | |
f23cc643 JB |
1889 | if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) |
1890 | dst_reg->min_value *= min_val; | |
1891 | if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) | |
1892 | dst_reg->max_value *= max_val; | |
d1174416 | 1893 | dst_reg->min_align = max(src_align, dst_align); |
48461135 JB |
1894 | break; |
1895 | case BPF_AND: | |
f23cc643 JB |
1896 | /* Disallow AND'ing of negative numbers, ain't nobody got time |
1897 | * for that. Otherwise the minimum is 0 and the max is the max | |
1898 | * value we could AND against. | |
1899 | */ | |
1900 | if (min_val < 0) | |
1901 | dst_reg->min_value = BPF_REGISTER_MIN_RANGE; | |
1902 | else | |
1903 | dst_reg->min_value = 0; | |
48461135 | 1904 | dst_reg->max_value = max_val; |
d1174416 | 1905 | dst_reg->min_align = max(src_align, dst_align); |
48461135 JB |
1906 | break; |
1907 | case BPF_LSH: | |
1908 | /* Gotta have special overflow logic here, if we're shifting | |
1909 | * more than MAX_RANGE then just assume we have an invalid | |
1910 | * range. | |
1911 | */ | |
d1174416 | 1912 | if (min_val > ilog2(BPF_REGISTER_MAX_RANGE)) { |
48461135 | 1913 | dst_reg->min_value = BPF_REGISTER_MIN_RANGE; |
d1174416 DM |
1914 | dst_reg->min_align = 1; |
1915 | } else { | |
1916 | if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) | |
1917 | dst_reg->min_value <<= min_val; | |
1918 | if (!dst_reg->min_align) | |
1919 | dst_reg->min_align = 1; | |
1920 | dst_reg->min_align <<= min_val; | |
1921 | } | |
48461135 JB |
1922 | if (max_val > ilog2(BPF_REGISTER_MAX_RANGE)) |
1923 | dst_reg->max_value = BPF_REGISTER_MAX_RANGE; | |
f23cc643 | 1924 | else if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) |
48461135 JB |
1925 | dst_reg->max_value <<= max_val; |
1926 | break; | |
1927 | case BPF_RSH: | |
f23cc643 JB |
1928 | /* RSH by a negative number is undefined, and the BPF_RSH is an |
1929 | * unsigned shift, so make the appropriate casts. | |
48461135 | 1930 | */ |
d1174416 | 1931 | if (min_val < 0 || dst_reg->min_value < 0) { |
f23cc643 | 1932 | dst_reg->min_value = BPF_REGISTER_MIN_RANGE; |
d1174416 | 1933 | } else { |
f23cc643 JB |
1934 | dst_reg->min_value = |
1935 | (u64)(dst_reg->min_value) >> min_val; | |
d1174416 DM |
1936 | } |
1937 | if (min_val < 0) { | |
1938 | dst_reg->min_align = 1; | |
1939 | } else { | |
1940 | dst_reg->min_align >>= (u64) min_val; | |
1941 | if (!dst_reg->min_align) | |
1942 | dst_reg->min_align = 1; | |
1943 | } | |
f23cc643 JB |
1944 | if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) |
1945 | dst_reg->max_value >>= max_val; | |
48461135 JB |
1946 | break; |
1947 | default: | |
1948 | reset_reg_range_values(regs, insn->dst_reg); | |
1949 | break; | |
1950 | } | |
1951 | ||
1952 | check_reg_overflow(dst_reg); | |
1953 | } | |
1954 | ||
17a52670 | 1955 | /* check validity of 32-bit and 64-bit arithmetic operations */ |
58e2af8b | 1956 | static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) |
17a52670 | 1957 | { |
58e2af8b | 1958 | struct bpf_reg_state *regs = env->cur_state.regs, *dst_reg; |
17a52670 AS |
1959 | u8 opcode = BPF_OP(insn->code); |
1960 | int err; | |
1961 | ||
1962 | if (opcode == BPF_END || opcode == BPF_NEG) { | |
1963 | if (opcode == BPF_NEG) { | |
1964 | if (BPF_SRC(insn->code) != 0 || | |
1965 | insn->src_reg != BPF_REG_0 || | |
1966 | insn->off != 0 || insn->imm != 0) { | |
1967 | verbose("BPF_NEG uses reserved fields\n"); | |
1968 | return -EINVAL; | |
1969 | } | |
1970 | } else { | |
1971 | if (insn->src_reg != BPF_REG_0 || insn->off != 0 || | |
1972 | (insn->imm != 16 && insn->imm != 32 && insn->imm != 64)) { | |
1973 | verbose("BPF_END uses reserved fields\n"); | |
1974 | return -EINVAL; | |
1975 | } | |
1976 | } | |
1977 | ||
1978 | /* check src operand */ | |
1979 | err = check_reg_arg(regs, insn->dst_reg, SRC_OP); | |
1980 | if (err) | |
1981 | return err; | |
1982 | ||
1be7f75d AS |
1983 | if (is_pointer_value(env, insn->dst_reg)) { |
1984 | verbose("R%d pointer arithmetic prohibited\n", | |
1985 | insn->dst_reg); | |
1986 | return -EACCES; | |
1987 | } | |
1988 | ||
17a52670 AS |
1989 | /* check dest operand */ |
1990 | err = check_reg_arg(regs, insn->dst_reg, DST_OP); | |
1991 | if (err) | |
1992 | return err; | |
1993 | ||
1994 | } else if (opcode == BPF_MOV) { | |
1995 | ||
1996 | if (BPF_SRC(insn->code) == BPF_X) { | |
1997 | if (insn->imm != 0 || insn->off != 0) { | |
1998 | verbose("BPF_MOV uses reserved fields\n"); | |
1999 | return -EINVAL; | |
2000 | } | |
2001 | ||
2002 | /* check src operand */ | |
2003 | err = check_reg_arg(regs, insn->src_reg, SRC_OP); | |
2004 | if (err) | |
2005 | return err; | |
2006 | } else { | |
2007 | if (insn->src_reg != BPF_REG_0 || insn->off != 0) { | |
2008 | verbose("BPF_MOV uses reserved fields\n"); | |
2009 | return -EINVAL; | |
2010 | } | |
2011 | } | |
2012 | ||
2013 | /* check dest operand */ | |
2014 | err = check_reg_arg(regs, insn->dst_reg, DST_OP); | |
2015 | if (err) | |
2016 | return err; | |
2017 | ||
48461135 JB |
2018 | /* we are setting our register to something new, we need to |
2019 | * reset its range values. | |
2020 | */ | |
2021 | reset_reg_range_values(regs, insn->dst_reg); | |
2022 | ||
17a52670 AS |
2023 | if (BPF_SRC(insn->code) == BPF_X) { |
2024 | if (BPF_CLASS(insn->code) == BPF_ALU64) { | |
2025 | /* case: R1 = R2 | |
2026 | * copy register state to dest reg | |
2027 | */ | |
2028 | regs[insn->dst_reg] = regs[insn->src_reg]; | |
2029 | } else { | |
1be7f75d AS |
2030 | if (is_pointer_value(env, insn->src_reg)) { |
2031 | verbose("R%d partial copy of pointer\n", | |
2032 | insn->src_reg); | |
2033 | return -EACCES; | |
2034 | } | |
57a09bf0 | 2035 | mark_reg_unknown_value(regs, insn->dst_reg); |
17a52670 AS |
2036 | } |
2037 | } else { | |
2038 | /* case: R = imm | |
2039 | * remember the value we stored into this reg | |
2040 | */ | |
2041 | regs[insn->dst_reg].type = CONST_IMM; | |
2042 | regs[insn->dst_reg].imm = insn->imm; | |
4a2ff55a | 2043 | regs[insn->dst_reg].id = 0; |
48461135 JB |
2044 | regs[insn->dst_reg].max_value = insn->imm; |
2045 | regs[insn->dst_reg].min_value = insn->imm; | |
d1174416 | 2046 | regs[insn->dst_reg].min_align = calc_align(insn->imm); |
4cabc5b1 | 2047 | regs[insn->dst_reg].value_from_signed = false; |
17a52670 AS |
2048 | } |
2049 | ||
2050 | } else if (opcode > BPF_END) { | |
2051 | verbose("invalid BPF_ALU opcode %x\n", opcode); | |
2052 | return -EINVAL; | |
2053 | ||
2054 | } else { /* all other ALU ops: and, sub, xor, add, ... */ | |
2055 | ||
17a52670 AS |
2056 | if (BPF_SRC(insn->code) == BPF_X) { |
2057 | if (insn->imm != 0 || insn->off != 0) { | |
2058 | verbose("BPF_ALU uses reserved fields\n"); | |
2059 | return -EINVAL; | |
2060 | } | |
2061 | /* check src1 operand */ | |
2062 | err = check_reg_arg(regs, insn->src_reg, SRC_OP); | |
2063 | if (err) | |
2064 | return err; | |
2065 | } else { | |
2066 | if (insn->src_reg != BPF_REG_0 || insn->off != 0) { | |
2067 | verbose("BPF_ALU uses reserved fields\n"); | |
2068 | return -EINVAL; | |
2069 | } | |
2070 | } | |
2071 | ||
2072 | /* check src2 operand */ | |
2073 | err = check_reg_arg(regs, insn->dst_reg, SRC_OP); | |
2074 | if (err) | |
2075 | return err; | |
2076 | ||
2077 | if ((opcode == BPF_MOD || opcode == BPF_DIV) && | |
2078 | BPF_SRC(insn->code) == BPF_K && insn->imm == 0) { | |
2079 | verbose("div by zero\n"); | |
2080 | return -EINVAL; | |
2081 | } | |
2082 | ||
229394e8 RV |
2083 | if ((opcode == BPF_LSH || opcode == BPF_RSH || |
2084 | opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) { | |
2085 | int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32; | |
2086 | ||
2087 | if (insn->imm < 0 || insn->imm >= size) { | |
2088 | verbose("invalid shift %d\n", insn->imm); | |
2089 | return -EINVAL; | |
2090 | } | |
2091 | } | |
2092 | ||
1a0dc1ac AS |
2093 | /* check dest operand */ |
2094 | err = check_reg_arg(regs, insn->dst_reg, DST_OP_NO_MARK); | |
2095 | if (err) | |
2096 | return err; | |
2097 | ||
2098 | dst_reg = ®s[insn->dst_reg]; | |
2099 | ||
48461135 JB |
2100 | /* first we want to adjust our ranges. */ |
2101 | adjust_reg_min_max_vals(env, insn); | |
2102 | ||
17a52670 AS |
2103 | /* pattern match 'bpf_add Rx, imm' instruction */ |
2104 | if (opcode == BPF_ADD && BPF_CLASS(insn->code) == BPF_ALU64 && | |
1a0dc1ac AS |
2105 | dst_reg->type == FRAME_PTR && BPF_SRC(insn->code) == BPF_K) { |
2106 | dst_reg->type = PTR_TO_STACK; | |
2107 | dst_reg->imm = insn->imm; | |
2108 | return 0; | |
332270fd YS |
2109 | } else if (opcode == BPF_ADD && |
2110 | BPF_CLASS(insn->code) == BPF_ALU64 && | |
2111 | dst_reg->type == PTR_TO_STACK && | |
2112 | ((BPF_SRC(insn->code) == BPF_X && | |
2113 | regs[insn->src_reg].type == CONST_IMM) || | |
2114 | BPF_SRC(insn->code) == BPF_K)) { | |
2115 | if (BPF_SRC(insn->code) == BPF_X) | |
2116 | dst_reg->imm += regs[insn->src_reg].imm; | |
2117 | else | |
2118 | dst_reg->imm += insn->imm; | |
2119 | return 0; | |
969bf05e AS |
2120 | } else if (opcode == BPF_ADD && |
2121 | BPF_CLASS(insn->code) == BPF_ALU64 && | |
1b9b69ec AS |
2122 | (dst_reg->type == PTR_TO_PACKET || |
2123 | (BPF_SRC(insn->code) == BPF_X && | |
2124 | regs[insn->src_reg].type == PTR_TO_PACKET))) { | |
969bf05e AS |
2125 | /* ptr_to_packet += K|X */ |
2126 | return check_packet_ptr_add(env, insn); | |
2127 | } else if (BPF_CLASS(insn->code) == BPF_ALU64 && | |
2128 | dst_reg->type == UNKNOWN_VALUE && | |
2129 | env->allow_ptr_leaks) { | |
2130 | /* unknown += K|X */ | |
2131 | return evaluate_reg_alu(env, insn); | |
2132 | } else if (BPF_CLASS(insn->code) == BPF_ALU64 && | |
2133 | dst_reg->type == CONST_IMM && | |
2134 | env->allow_ptr_leaks) { | |
2135 | /* reg_imm += K|X */ | |
2136 | return evaluate_reg_imm_alu(env, insn); | |
1be7f75d AS |
2137 | } else if (is_pointer_value(env, insn->dst_reg)) { |
2138 | verbose("R%d pointer arithmetic prohibited\n", | |
2139 | insn->dst_reg); | |
2140 | return -EACCES; | |
2141 | } else if (BPF_SRC(insn->code) == BPF_X && | |
2142 | is_pointer_value(env, insn->src_reg)) { | |
2143 | verbose("R%d pointer arithmetic prohibited\n", | |
2144 | insn->src_reg); | |
2145 | return -EACCES; | |
2146 | } | |
17a52670 | 2147 | |
48461135 JB |
2148 | /* If we did pointer math on a map value then just set it to our |
2149 | * PTR_TO_MAP_VALUE_ADJ type so we can deal with any stores or | |
2150 | * loads to this register appropriately, otherwise just mark the | |
2151 | * register as unknown. | |
2152 | */ | |
2153 | if (env->allow_ptr_leaks && | |
fce366a9 | 2154 | BPF_CLASS(insn->code) == BPF_ALU64 && opcode == BPF_ADD && |
48461135 JB |
2155 | (dst_reg->type == PTR_TO_MAP_VALUE || |
2156 | dst_reg->type == PTR_TO_MAP_VALUE_ADJ)) | |
2157 | dst_reg->type = PTR_TO_MAP_VALUE_ADJ; | |
2158 | else | |
2159 | mark_reg_unknown_value(regs, insn->dst_reg); | |
17a52670 AS |
2160 | } |
2161 | ||
2162 | return 0; | |
2163 | } | |
2164 | ||
58e2af8b JK |
2165 | static void find_good_pkt_pointers(struct bpf_verifier_state *state, |
2166 | struct bpf_reg_state *dst_reg) | |
969bf05e | 2167 | { |
58e2af8b | 2168 | struct bpf_reg_state *regs = state->regs, *reg; |
969bf05e | 2169 | int i; |
2d2be8ca DB |
2170 | |
2171 | /* LLVM can generate two kind of checks: | |
2172 | * | |
2173 | * Type 1: | |
2174 | * | |
2175 | * r2 = r3; | |
2176 | * r2 += 8; | |
2177 | * if (r2 > pkt_end) goto <handle exception> | |
2178 | * <access okay> | |
2179 | * | |
2180 | * Where: | |
2181 | * r2 == dst_reg, pkt_end == src_reg | |
2182 | * r2=pkt(id=n,off=8,r=0) | |
2183 | * r3=pkt(id=n,off=0,r=0) | |
2184 | * | |
2185 | * Type 2: | |
2186 | * | |
2187 | * r2 = r3; | |
2188 | * r2 += 8; | |
2189 | * if (pkt_end >= r2) goto <access okay> | |
2190 | * <handle exception> | |
2191 | * | |
2192 | * Where: | |
2193 | * pkt_end == dst_reg, r2 == src_reg | |
2194 | * r2=pkt(id=n,off=8,r=0) | |
2195 | * r3=pkt(id=n,off=0,r=0) | |
2196 | * | |
2197 | * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8) | |
2198 | * so that range of bytes [r3, r3 + 8) is safe to access. | |
969bf05e | 2199 | */ |
2d2be8ca | 2200 | |
969bf05e AS |
2201 | for (i = 0; i < MAX_BPF_REG; i++) |
2202 | if (regs[i].type == PTR_TO_PACKET && regs[i].id == dst_reg->id) | |
b1977682 AS |
2203 | /* keep the maximum range already checked */ |
2204 | regs[i].range = max(regs[i].range, dst_reg->off); | |
969bf05e AS |
2205 | |
2206 | for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) { | |
2207 | if (state->stack_slot_type[i] != STACK_SPILL) | |
2208 | continue; | |
2209 | reg = &state->spilled_regs[i / BPF_REG_SIZE]; | |
2210 | if (reg->type == PTR_TO_PACKET && reg->id == dst_reg->id) | |
b1977682 | 2211 | reg->range = max(reg->range, dst_reg->off); |
969bf05e AS |
2212 | } |
2213 | } | |
2214 | ||
48461135 JB |
2215 | /* Adjusts the register min/max values in the case that the dst_reg is the |
2216 | * variable register that we are working on, and src_reg is a constant or we're | |
2217 | * simply doing a BPF_K check. | |
2218 | */ | |
2219 | static void reg_set_min_max(struct bpf_reg_state *true_reg, | |
2220 | struct bpf_reg_state *false_reg, u64 val, | |
2221 | u8 opcode) | |
2222 | { | |
4cabc5b1 DB |
2223 | bool value_from_signed = true; |
2224 | bool is_range = true; | |
2225 | ||
48461135 JB |
2226 | switch (opcode) { |
2227 | case BPF_JEQ: | |
2228 | /* If this is false then we know nothing Jon Snow, but if it is | |
2229 | * true then we know for sure. | |
2230 | */ | |
2231 | true_reg->max_value = true_reg->min_value = val; | |
4cabc5b1 | 2232 | is_range = false; |
48461135 JB |
2233 | break; |
2234 | case BPF_JNE: | |
2235 | /* If this is true we know nothing Jon Snow, but if it is false | |
2236 | * we know the value for sure; | |
2237 | */ | |
2238 | false_reg->max_value = false_reg->min_value = val; | |
4cabc5b1 | 2239 | is_range = false; |
48461135 JB |
2240 | break; |
2241 | case BPF_JGT: | |
4cabc5b1 | 2242 | value_from_signed = false; |
7e57fbb2 | 2243 | /* fallthrough */ |
48461135 | 2244 | case BPF_JSGT: |
4cabc5b1 DB |
2245 | if (true_reg->value_from_signed != value_from_signed) |
2246 | reset_reg_range_values(true_reg, 0); | |
2247 | if (false_reg->value_from_signed != value_from_signed) | |
2248 | reset_reg_range_values(false_reg, 0); | |
2249 | if (opcode == BPF_JGT) { | |
2250 | /* Unsigned comparison, the minimum value is 0. */ | |
2251 | false_reg->min_value = 0; | |
2252 | } | |
48461135 JB |
2253 | /* If this is false then we know the maximum val is val, |
2254 | * otherwise we know the min val is val+1. | |
2255 | */ | |
2256 | false_reg->max_value = val; | |
4cabc5b1 | 2257 | false_reg->value_from_signed = value_from_signed; |
48461135 | 2258 | true_reg->min_value = val + 1; |
4cabc5b1 | 2259 | true_reg->value_from_signed = value_from_signed; |
48461135 JB |
2260 | break; |
2261 | case BPF_JGE: | |
4cabc5b1 | 2262 | value_from_signed = false; |
7e57fbb2 | 2263 | /* fallthrough */ |
48461135 | 2264 | case BPF_JSGE: |
4cabc5b1 DB |
2265 | if (true_reg->value_from_signed != value_from_signed) |
2266 | reset_reg_range_values(true_reg, 0); | |
2267 | if (false_reg->value_from_signed != value_from_signed) | |
2268 | reset_reg_range_values(false_reg, 0); | |
2269 | if (opcode == BPF_JGE) { | |
2270 | /* Unsigned comparison, the minimum value is 0. */ | |
2271 | false_reg->min_value = 0; | |
2272 | } | |
48461135 JB |
2273 | /* If this is false then we know the maximum value is val - 1, |
2274 | * otherwise we know the mimimum value is val. | |
2275 | */ | |
2276 | false_reg->max_value = val - 1; | |
4cabc5b1 | 2277 | false_reg->value_from_signed = value_from_signed; |
48461135 | 2278 | true_reg->min_value = val; |
4cabc5b1 | 2279 | true_reg->value_from_signed = value_from_signed; |
48461135 JB |
2280 | break; |
2281 | default: | |
2282 | break; | |
2283 | } | |
2284 | ||
2285 | check_reg_overflow(false_reg); | |
2286 | check_reg_overflow(true_reg); | |
4cabc5b1 DB |
2287 | if (is_range) { |
2288 | if (__is_pointer_value(false, false_reg)) | |
2289 | reset_reg_range_values(false_reg, 0); | |
2290 | if (__is_pointer_value(false, true_reg)) | |
2291 | reset_reg_range_values(true_reg, 0); | |
2292 | } | |
48461135 JB |
2293 | } |
2294 | ||
2295 | /* Same as above, but for the case that dst_reg is a CONST_IMM reg and src_reg | |
2296 | * is the variable reg. | |
2297 | */ | |
2298 | static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, | |
2299 | struct bpf_reg_state *false_reg, u64 val, | |
2300 | u8 opcode) | |
2301 | { | |
4cabc5b1 DB |
2302 | bool value_from_signed = true; |
2303 | bool is_range = true; | |
2304 | ||
48461135 JB |
2305 | switch (opcode) { |
2306 | case BPF_JEQ: | |
2307 | /* If this is false then we know nothing Jon Snow, but if it is | |
2308 | * true then we know for sure. | |
2309 | */ | |
2310 | true_reg->max_value = true_reg->min_value = val; | |
4cabc5b1 | 2311 | is_range = false; |
48461135 JB |
2312 | break; |
2313 | case BPF_JNE: | |
2314 | /* If this is true we know nothing Jon Snow, but if it is false | |
2315 | * we know the value for sure; | |
2316 | */ | |
2317 | false_reg->max_value = false_reg->min_value = val; | |
4cabc5b1 | 2318 | is_range = false; |
48461135 JB |
2319 | break; |
2320 | case BPF_JGT: | |
4cabc5b1 | 2321 | value_from_signed = false; |
7e57fbb2 | 2322 | /* fallthrough */ |
48461135 | 2323 | case BPF_JSGT: |
4cabc5b1 DB |
2324 | if (true_reg->value_from_signed != value_from_signed) |
2325 | reset_reg_range_values(true_reg, 0); | |
2326 | if (false_reg->value_from_signed != value_from_signed) | |
2327 | reset_reg_range_values(false_reg, 0); | |
2328 | if (opcode == BPF_JGT) { | |
2329 | /* Unsigned comparison, the minimum value is 0. */ | |
2330 | true_reg->min_value = 0; | |
2331 | } | |
48461135 JB |
2332 | /* |
2333 | * If this is false, then the val is <= the register, if it is | |
2334 | * true the register <= to the val. | |
2335 | */ | |
2336 | false_reg->min_value = val; | |
4cabc5b1 | 2337 | false_reg->value_from_signed = value_from_signed; |
48461135 | 2338 | true_reg->max_value = val - 1; |
4cabc5b1 | 2339 | true_reg->value_from_signed = value_from_signed; |
48461135 JB |
2340 | break; |
2341 | case BPF_JGE: | |
4cabc5b1 | 2342 | value_from_signed = false; |
7e57fbb2 | 2343 | /* fallthrough */ |
48461135 | 2344 | case BPF_JSGE: |
4cabc5b1 DB |
2345 | if (true_reg->value_from_signed != value_from_signed) |
2346 | reset_reg_range_values(true_reg, 0); | |
2347 | if (false_reg->value_from_signed != value_from_signed) | |
2348 | reset_reg_range_values(false_reg, 0); | |
2349 | if (opcode == BPF_JGE) { | |
2350 | /* Unsigned comparison, the minimum value is 0. */ | |
2351 | true_reg->min_value = 0; | |
2352 | } | |
48461135 JB |
2353 | /* If this is false then constant < register, if it is true then |
2354 | * the register < constant. | |
2355 | */ | |
2356 | false_reg->min_value = val + 1; | |
4cabc5b1 | 2357 | false_reg->value_from_signed = value_from_signed; |
48461135 | 2358 | true_reg->max_value = val; |
4cabc5b1 | 2359 | true_reg->value_from_signed = value_from_signed; |
48461135 JB |
2360 | break; |
2361 | default: | |
2362 | break; | |
2363 | } | |
2364 | ||
2365 | check_reg_overflow(false_reg); | |
2366 | check_reg_overflow(true_reg); | |
4cabc5b1 DB |
2367 | if (is_range) { |
2368 | if (__is_pointer_value(false, false_reg)) | |
2369 | reset_reg_range_values(false_reg, 0); | |
2370 | if (__is_pointer_value(false, true_reg)) | |
2371 | reset_reg_range_values(true_reg, 0); | |
2372 | } | |
48461135 JB |
2373 | } |
2374 | ||
57a09bf0 TG |
2375 | static void mark_map_reg(struct bpf_reg_state *regs, u32 regno, u32 id, |
2376 | enum bpf_reg_type type) | |
2377 | { | |
2378 | struct bpf_reg_state *reg = ®s[regno]; | |
2379 | ||
2380 | if (reg->type == PTR_TO_MAP_VALUE_OR_NULL && reg->id == id) { | |
56f668df MKL |
2381 | if (type == UNKNOWN_VALUE) { |
2382 | __mark_reg_unknown_value(regs, regno); | |
2383 | } else if (reg->map_ptr->inner_map_meta) { | |
2384 | reg->type = CONST_PTR_TO_MAP; | |
2385 | reg->map_ptr = reg->map_ptr->inner_map_meta; | |
2386 | } else { | |
2387 | reg->type = type; | |
2388 | } | |
a08dd0da DB |
2389 | /* We don't need id from this point onwards anymore, thus we |
2390 | * should better reset it, so that state pruning has chances | |
2391 | * to take effect. | |
2392 | */ | |
2393 | reg->id = 0; | |
57a09bf0 TG |
2394 | } |
2395 | } | |
2396 | ||
2397 | /* The logic is similar to find_good_pkt_pointers(), both could eventually | |
2398 | * be folded together at some point. | |
2399 | */ | |
2400 | static void mark_map_regs(struct bpf_verifier_state *state, u32 regno, | |
2401 | enum bpf_reg_type type) | |
2402 | { | |
2403 | struct bpf_reg_state *regs = state->regs; | |
a08dd0da | 2404 | u32 id = regs[regno].id; |
57a09bf0 TG |
2405 | int i; |
2406 | ||
2407 | for (i = 0; i < MAX_BPF_REG; i++) | |
a08dd0da | 2408 | mark_map_reg(regs, i, id, type); |
57a09bf0 TG |
2409 | |
2410 | for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) { | |
2411 | if (state->stack_slot_type[i] != STACK_SPILL) | |
2412 | continue; | |
a08dd0da | 2413 | mark_map_reg(state->spilled_regs, i / BPF_REG_SIZE, id, type); |
57a09bf0 TG |
2414 | } |
2415 | } | |
2416 | ||
58e2af8b | 2417 | static int check_cond_jmp_op(struct bpf_verifier_env *env, |
17a52670 AS |
2418 | struct bpf_insn *insn, int *insn_idx) |
2419 | { | |
58e2af8b JK |
2420 | struct bpf_verifier_state *other_branch, *this_branch = &env->cur_state; |
2421 | struct bpf_reg_state *regs = this_branch->regs, *dst_reg; | |
17a52670 AS |
2422 | u8 opcode = BPF_OP(insn->code); |
2423 | int err; | |
2424 | ||
2425 | if (opcode > BPF_EXIT) { | |
2426 | verbose("invalid BPF_JMP opcode %x\n", opcode); | |
2427 | return -EINVAL; | |
2428 | } | |
2429 | ||
2430 | if (BPF_SRC(insn->code) == BPF_X) { | |
2431 | if (insn->imm != 0) { | |
2432 | verbose("BPF_JMP uses reserved fields\n"); | |
2433 | return -EINVAL; | |
2434 | } | |
2435 | ||
2436 | /* check src1 operand */ | |
2437 | err = check_reg_arg(regs, insn->src_reg, SRC_OP); | |
2438 | if (err) | |
2439 | return err; | |
1be7f75d AS |
2440 | |
2441 | if (is_pointer_value(env, insn->src_reg)) { | |
2442 | verbose("R%d pointer comparison prohibited\n", | |
2443 | insn->src_reg); | |
2444 | return -EACCES; | |
2445 | } | |
17a52670 AS |
2446 | } else { |
2447 | if (insn->src_reg != BPF_REG_0) { | |
2448 | verbose("BPF_JMP uses reserved fields\n"); | |
2449 | return -EINVAL; | |
2450 | } | |
2451 | } | |
2452 | ||
2453 | /* check src2 operand */ | |
2454 | err = check_reg_arg(regs, insn->dst_reg, SRC_OP); | |
2455 | if (err) | |
2456 | return err; | |
2457 | ||
1a0dc1ac AS |
2458 | dst_reg = ®s[insn->dst_reg]; |
2459 | ||
17a52670 AS |
2460 | /* detect if R == 0 where R was initialized to zero earlier */ |
2461 | if (BPF_SRC(insn->code) == BPF_K && | |
2462 | (opcode == BPF_JEQ || opcode == BPF_JNE) && | |
1a0dc1ac | 2463 | dst_reg->type == CONST_IMM && dst_reg->imm == insn->imm) { |
17a52670 AS |
2464 | if (opcode == BPF_JEQ) { |
2465 | /* if (imm == imm) goto pc+off; | |
2466 | * only follow the goto, ignore fall-through | |
2467 | */ | |
2468 | *insn_idx += insn->off; | |
2469 | return 0; | |
2470 | } else { | |
2471 | /* if (imm != imm) goto pc+off; | |
2472 | * only follow fall-through branch, since | |
2473 | * that's where the program will go | |
2474 | */ | |
2475 | return 0; | |
2476 | } | |
2477 | } | |
2478 | ||
2479 | other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx); | |
2480 | if (!other_branch) | |
2481 | return -EFAULT; | |
2482 | ||
48461135 JB |
2483 | /* detect if we are comparing against a constant value so we can adjust |
2484 | * our min/max values for our dst register. | |
2485 | */ | |
2486 | if (BPF_SRC(insn->code) == BPF_X) { | |
2487 | if (regs[insn->src_reg].type == CONST_IMM) | |
2488 | reg_set_min_max(&other_branch->regs[insn->dst_reg], | |
2489 | dst_reg, regs[insn->src_reg].imm, | |
2490 | opcode); | |
2491 | else if (dst_reg->type == CONST_IMM) | |
2492 | reg_set_min_max_inv(&other_branch->regs[insn->src_reg], | |
2493 | ®s[insn->src_reg], dst_reg->imm, | |
2494 | opcode); | |
2495 | } else { | |
2496 | reg_set_min_max(&other_branch->regs[insn->dst_reg], | |
2497 | dst_reg, insn->imm, opcode); | |
2498 | } | |
2499 | ||
58e2af8b | 2500 | /* detect if R == 0 where R is returned from bpf_map_lookup_elem() */ |
17a52670 | 2501 | if (BPF_SRC(insn->code) == BPF_K && |
1a0dc1ac AS |
2502 | insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) && |
2503 | dst_reg->type == PTR_TO_MAP_VALUE_OR_NULL) { | |
57a09bf0 TG |
2504 | /* Mark all identical map registers in each branch as either |
2505 | * safe or unknown depending R == 0 or R != 0 conditional. | |
2506 | */ | |
2507 | mark_map_regs(this_branch, insn->dst_reg, | |
2508 | opcode == BPF_JEQ ? PTR_TO_MAP_VALUE : UNKNOWN_VALUE); | |
2509 | mark_map_regs(other_branch, insn->dst_reg, | |
2510 | opcode == BPF_JEQ ? UNKNOWN_VALUE : PTR_TO_MAP_VALUE); | |
969bf05e AS |
2511 | } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGT && |
2512 | dst_reg->type == PTR_TO_PACKET && | |
2513 | regs[insn->src_reg].type == PTR_TO_PACKET_END) { | |
2d2be8ca DB |
2514 | find_good_pkt_pointers(this_branch, dst_reg); |
2515 | } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGE && | |
2516 | dst_reg->type == PTR_TO_PACKET_END && | |
2517 | regs[insn->src_reg].type == PTR_TO_PACKET) { | |
2518 | find_good_pkt_pointers(other_branch, ®s[insn->src_reg]); | |
1be7f75d AS |
2519 | } else if (is_pointer_value(env, insn->dst_reg)) { |
2520 | verbose("R%d pointer comparison prohibited\n", insn->dst_reg); | |
2521 | return -EACCES; | |
17a52670 AS |
2522 | } |
2523 | if (log_level) | |
2d2be8ca | 2524 | print_verifier_state(this_branch); |
17a52670 AS |
2525 | return 0; |
2526 | } | |
2527 | ||
0246e64d AS |
2528 | /* return the map pointer stored inside BPF_LD_IMM64 instruction */ |
2529 | static struct bpf_map *ld_imm64_to_map_ptr(struct bpf_insn *insn) | |
2530 | { | |
2531 | u64 imm64 = ((u64) (u32) insn[0].imm) | ((u64) (u32) insn[1].imm) << 32; | |
2532 | ||
2533 | return (struct bpf_map *) (unsigned long) imm64; | |
2534 | } | |
2535 | ||
17a52670 | 2536 | /* verify BPF_LD_IMM64 instruction */ |
58e2af8b | 2537 | static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) |
17a52670 | 2538 | { |
58e2af8b | 2539 | struct bpf_reg_state *regs = env->cur_state.regs; |
17a52670 AS |
2540 | int err; |
2541 | ||
2542 | if (BPF_SIZE(insn->code) != BPF_DW) { | |
2543 | verbose("invalid BPF_LD_IMM insn\n"); | |
2544 | return -EINVAL; | |
2545 | } | |
2546 | if (insn->off != 0) { | |
2547 | verbose("BPF_LD_IMM64 uses reserved fields\n"); | |
2548 | return -EINVAL; | |
2549 | } | |
2550 | ||
2551 | err = check_reg_arg(regs, insn->dst_reg, DST_OP); | |
2552 | if (err) | |
2553 | return err; | |
2554 | ||
6b173873 | 2555 | if (insn->src_reg == 0) { |
6b173873 JK |
2556 | u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; |
2557 | ||
6b173873 JK |
2558 | regs[insn->dst_reg].type = CONST_IMM; |
2559 | regs[insn->dst_reg].imm = imm; | |
4a2ff55a | 2560 | regs[insn->dst_reg].id = 0; |
17a52670 | 2561 | return 0; |
6b173873 | 2562 | } |
17a52670 AS |
2563 | |
2564 | /* replace_map_fd_with_map_ptr() should have caught bad ld_imm64 */ | |
2565 | BUG_ON(insn->src_reg != BPF_PSEUDO_MAP_FD); | |
2566 | ||
2567 | regs[insn->dst_reg].type = CONST_PTR_TO_MAP; | |
2568 | regs[insn->dst_reg].map_ptr = ld_imm64_to_map_ptr(insn); | |
2569 | return 0; | |
2570 | } | |
2571 | ||
96be4325 DB |
2572 | static bool may_access_skb(enum bpf_prog_type type) |
2573 | { | |
2574 | switch (type) { | |
2575 | case BPF_PROG_TYPE_SOCKET_FILTER: | |
2576 | case BPF_PROG_TYPE_SCHED_CLS: | |
94caee8c | 2577 | case BPF_PROG_TYPE_SCHED_ACT: |
96be4325 DB |
2578 | return true; |
2579 | default: | |
2580 | return false; | |
2581 | } | |
2582 | } | |
2583 | ||
ddd872bc AS |
2584 | /* verify safety of LD_ABS|LD_IND instructions: |
2585 | * - they can only appear in the programs where ctx == skb | |
2586 | * - since they are wrappers of function calls, they scratch R1-R5 registers, | |
2587 | * preserve R6-R9, and store return value into R0 | |
2588 | * | |
2589 | * Implicit input: | |
2590 | * ctx == skb == R6 == CTX | |
2591 | * | |
2592 | * Explicit input: | |
2593 | * SRC == any register | |
2594 | * IMM == 32-bit immediate | |
2595 | * | |
2596 | * Output: | |
2597 | * R0 - 8/16/32-bit skb data converted to cpu endianness | |
2598 | */ | |
58e2af8b | 2599 | static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) |
ddd872bc | 2600 | { |
58e2af8b | 2601 | struct bpf_reg_state *regs = env->cur_state.regs; |
ddd872bc | 2602 | u8 mode = BPF_MODE(insn->code); |
ddd872bc AS |
2603 | int i, err; |
2604 | ||
24701ece | 2605 | if (!may_access_skb(env->prog->type)) { |
1a0dc1ac | 2606 | verbose("BPF_LD_[ABS|IND] instructions not allowed for this program type\n"); |
ddd872bc AS |
2607 | return -EINVAL; |
2608 | } | |
2609 | ||
2610 | if (insn->dst_reg != BPF_REG_0 || insn->off != 0 || | |
d82bccc6 | 2611 | BPF_SIZE(insn->code) == BPF_DW || |
ddd872bc | 2612 | (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) { |
1a0dc1ac | 2613 | verbose("BPF_LD_[ABS|IND] uses reserved fields\n"); |
ddd872bc AS |
2614 | return -EINVAL; |
2615 | } | |
2616 | ||
2617 | /* check whether implicit source operand (register R6) is readable */ | |
2618 | err = check_reg_arg(regs, BPF_REG_6, SRC_OP); | |
2619 | if (err) | |
2620 | return err; | |
2621 | ||
2622 | if (regs[BPF_REG_6].type != PTR_TO_CTX) { | |
2623 | verbose("at the time of BPF_LD_ABS|IND R6 != pointer to skb\n"); | |
2624 | return -EINVAL; | |
2625 | } | |
2626 | ||
2627 | if (mode == BPF_IND) { | |
2628 | /* check explicit source operand */ | |
2629 | err = check_reg_arg(regs, insn->src_reg, SRC_OP); | |
2630 | if (err) | |
2631 | return err; | |
2632 | } | |
2633 | ||
2634 | /* reset caller saved regs to unreadable */ | |
a9789ef9 DB |
2635 | for (i = 0; i < CALLER_SAVED_REGS; i++) |
2636 | mark_reg_not_init(regs, caller_saved[i]); | |
ddd872bc AS |
2637 | |
2638 | /* mark destination R0 register as readable, since it contains | |
2639 | * the value fetched from the packet | |
2640 | */ | |
2641 | regs[BPF_REG_0].type = UNKNOWN_VALUE; | |
2642 | return 0; | |
2643 | } | |
2644 | ||
475fb78f AS |
2645 | /* non-recursive DFS pseudo code |
2646 | * 1 procedure DFS-iterative(G,v): | |
2647 | * 2 label v as discovered | |
2648 | * 3 let S be a stack | |
2649 | * 4 S.push(v) | |
2650 | * 5 while S is not empty | |
2651 | * 6 t <- S.pop() | |
2652 | * 7 if t is what we're looking for: | |
2653 | * 8 return t | |
2654 | * 9 for all edges e in G.adjacentEdges(t) do | |
2655 | * 10 if edge e is already labelled | |
2656 | * 11 continue with the next edge | |
2657 | * 12 w <- G.adjacentVertex(t,e) | |
2658 | * 13 if vertex w is not discovered and not explored | |
2659 | * 14 label e as tree-edge | |
2660 | * 15 label w as discovered | |
2661 | * 16 S.push(w) | |
2662 | * 17 continue at 5 | |
2663 | * 18 else if vertex w is discovered | |
2664 | * 19 label e as back-edge | |
2665 | * 20 else | |
2666 | * 21 // vertex w is explored | |
2667 | * 22 label e as forward- or cross-edge | |
2668 | * 23 label t as explored | |
2669 | * 24 S.pop() | |
2670 | * | |
2671 | * convention: | |
2672 | * 0x10 - discovered | |
2673 | * 0x11 - discovered and fall-through edge labelled | |
2674 | * 0x12 - discovered and fall-through and branch edges labelled | |
2675 | * 0x20 - explored | |
2676 | */ | |
2677 | ||
2678 | enum { | |
2679 | DISCOVERED = 0x10, | |
2680 | EXPLORED = 0x20, | |
2681 | FALLTHROUGH = 1, | |
2682 | BRANCH = 2, | |
2683 | }; | |
2684 | ||
58e2af8b | 2685 | #define STATE_LIST_MARK ((struct bpf_verifier_state_list *) -1L) |
f1bca824 | 2686 | |
475fb78f AS |
2687 | static int *insn_stack; /* stack of insns to process */ |
2688 | static int cur_stack; /* current stack index */ | |
2689 | static int *insn_state; | |
2690 | ||
2691 | /* t, w, e - match pseudo-code above: | |
2692 | * t - index of current instruction | |
2693 | * w - next instruction | |
2694 | * e - edge | |
2695 | */ | |
58e2af8b | 2696 | static int push_insn(int t, int w, int e, struct bpf_verifier_env *env) |
475fb78f AS |
2697 | { |
2698 | if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH)) | |
2699 | return 0; | |
2700 | ||
2701 | if (e == BRANCH && insn_state[t] >= (DISCOVERED | BRANCH)) | |
2702 | return 0; | |
2703 | ||
2704 | if (w < 0 || w >= env->prog->len) { | |
2705 | verbose("jump out of range from insn %d to %d\n", t, w); | |
2706 | return -EINVAL; | |
2707 | } | |
2708 | ||
f1bca824 AS |
2709 | if (e == BRANCH) |
2710 | /* mark branch target for state pruning */ | |
2711 | env->explored_states[w] = STATE_LIST_MARK; | |
2712 | ||
475fb78f AS |
2713 | if (insn_state[w] == 0) { |
2714 | /* tree-edge */ | |
2715 | insn_state[t] = DISCOVERED | e; | |
2716 | insn_state[w] = DISCOVERED; | |
2717 | if (cur_stack >= env->prog->len) | |
2718 | return -E2BIG; | |
2719 | insn_stack[cur_stack++] = w; | |
2720 | return 1; | |
2721 | } else if ((insn_state[w] & 0xF0) == DISCOVERED) { | |
2722 | verbose("back-edge from insn %d to %d\n", t, w); | |
2723 | return -EINVAL; | |
2724 | } else if (insn_state[w] == EXPLORED) { | |
2725 | /* forward- or cross-edge */ | |
2726 | insn_state[t] = DISCOVERED | e; | |
2727 | } else { | |
2728 | verbose("insn state internal bug\n"); | |
2729 | return -EFAULT; | |
2730 | } | |
2731 | return 0; | |
2732 | } | |
2733 | ||
2734 | /* non-recursive depth-first-search to detect loops in BPF program | |
2735 | * loop == back-edge in directed graph | |
2736 | */ | |
58e2af8b | 2737 | static int check_cfg(struct bpf_verifier_env *env) |
475fb78f AS |
2738 | { |
2739 | struct bpf_insn *insns = env->prog->insnsi; | |
2740 | int insn_cnt = env->prog->len; | |
2741 | int ret = 0; | |
2742 | int i, t; | |
2743 | ||
2744 | insn_state = kcalloc(insn_cnt, sizeof(int), GFP_KERNEL); | |
2745 | if (!insn_state) | |
2746 | return -ENOMEM; | |
2747 | ||
2748 | insn_stack = kcalloc(insn_cnt, sizeof(int), GFP_KERNEL); | |
2749 | if (!insn_stack) { | |
2750 | kfree(insn_state); | |
2751 | return -ENOMEM; | |
2752 | } | |
2753 | ||
2754 | insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */ | |
2755 | insn_stack[0] = 0; /* 0 is the first instruction */ | |
2756 | cur_stack = 1; | |
2757 | ||
2758 | peek_stack: | |
2759 | if (cur_stack == 0) | |
2760 | goto check_state; | |
2761 | t = insn_stack[cur_stack - 1]; | |
2762 | ||
2763 | if (BPF_CLASS(insns[t].code) == BPF_JMP) { | |
2764 | u8 opcode = BPF_OP(insns[t].code); | |
2765 | ||
2766 | if (opcode == BPF_EXIT) { | |
2767 | goto mark_explored; | |
2768 | } else if (opcode == BPF_CALL) { | |
2769 | ret = push_insn(t, t + 1, FALLTHROUGH, env); | |
2770 | if (ret == 1) | |
2771 | goto peek_stack; | |
2772 | else if (ret < 0) | |
2773 | goto err_free; | |
07016151 DB |
2774 | if (t + 1 < insn_cnt) |
2775 | env->explored_states[t + 1] = STATE_LIST_MARK; | |
475fb78f AS |
2776 | } else if (opcode == BPF_JA) { |
2777 | if (BPF_SRC(insns[t].code) != BPF_K) { | |
2778 | ret = -EINVAL; | |
2779 | goto err_free; | |
2780 | } | |
2781 | /* unconditional jump with single edge */ | |
2782 | ret = push_insn(t, t + insns[t].off + 1, | |
2783 | FALLTHROUGH, env); | |
2784 | if (ret == 1) | |
2785 | goto peek_stack; | |
2786 | else if (ret < 0) | |
2787 | goto err_free; | |
f1bca824 AS |
2788 | /* tell verifier to check for equivalent states |
2789 | * after every call and jump | |
2790 | */ | |
c3de6317 AS |
2791 | if (t + 1 < insn_cnt) |
2792 | env->explored_states[t + 1] = STATE_LIST_MARK; | |
475fb78f AS |
2793 | } else { |
2794 | /* conditional jump with two edges */ | |
3c2ce60b | 2795 | env->explored_states[t] = STATE_LIST_MARK; |
475fb78f AS |
2796 | ret = push_insn(t, t + 1, FALLTHROUGH, env); |
2797 | if (ret == 1) | |
2798 | goto peek_stack; | |
2799 | else if (ret < 0) | |
2800 | goto err_free; | |
2801 | ||
2802 | ret = push_insn(t, t + insns[t].off + 1, BRANCH, env); | |
2803 | if (ret == 1) | |
2804 | goto peek_stack; | |
2805 | else if (ret < 0) | |
2806 | goto err_free; | |
2807 | } | |
2808 | } else { | |
2809 | /* all other non-branch instructions with single | |
2810 | * fall-through edge | |
2811 | */ | |
2812 | ret = push_insn(t, t + 1, FALLTHROUGH, env); | |
2813 | if (ret == 1) | |
2814 | goto peek_stack; | |
2815 | else if (ret < 0) | |
2816 | goto err_free; | |
2817 | } | |
2818 | ||
2819 | mark_explored: | |
2820 | insn_state[t] = EXPLORED; | |
2821 | if (cur_stack-- <= 0) { | |
2822 | verbose("pop stack internal bug\n"); | |
2823 | ret = -EFAULT; | |
2824 | goto err_free; | |
2825 | } | |
2826 | goto peek_stack; | |
2827 | ||
2828 | check_state: | |
2829 | for (i = 0; i < insn_cnt; i++) { | |
2830 | if (insn_state[i] != EXPLORED) { | |
2831 | verbose("unreachable insn %d\n", i); | |
2832 | ret = -EINVAL; | |
2833 | goto err_free; | |
2834 | } | |
2835 | } | |
2836 | ret = 0; /* cfg looks good */ | |
2837 | ||
2838 | err_free: | |
2839 | kfree(insn_state); | |
2840 | kfree(insn_stack); | |
2841 | return ret; | |
2842 | } | |
2843 | ||
969bf05e AS |
2844 | /* the following conditions reduce the number of explored insns |
2845 | * from ~140k to ~80k for ultra large programs that use a lot of ptr_to_packet | |
2846 | */ | |
1ad2f583 DB |
2847 | static bool compare_ptrs_to_packet(struct bpf_verifier_env *env, |
2848 | struct bpf_reg_state *old, | |
58e2af8b | 2849 | struct bpf_reg_state *cur) |
969bf05e AS |
2850 | { |
2851 | if (old->id != cur->id) | |
2852 | return false; | |
2853 | ||
2854 | /* old ptr_to_packet is more conservative, since it allows smaller | |
2855 | * range. Ex: | |
2856 | * old(off=0,r=10) is equal to cur(off=0,r=20), because | |
2857 | * old(off=0,r=10) means that with range=10 the verifier proceeded | |
2858 | * further and found no issues with the program. Now we're in the same | |
2859 | * spot with cur(off=0,r=20), so we're safe too, since anything further | |
2860 | * will only be looking at most 10 bytes after this pointer. | |
2861 | */ | |
2862 | if (old->off == cur->off && old->range < cur->range) | |
2863 | return true; | |
2864 | ||
2865 | /* old(off=20,r=10) is equal to cur(off=22,re=22 or 5 or 0) | |
2866 | * since both cannot be used for packet access and safe(old) | |
2867 | * pointer has smaller off that could be used for further | |
2868 | * 'if (ptr > data_end)' check | |
2869 | * Ex: | |
2870 | * old(off=20,r=10) and cur(off=22,r=22) and cur(off=22,r=0) mean | |
2871 | * that we cannot access the packet. | |
2872 | * The safe range is: | |
2873 | * [ptr, ptr + range - off) | |
2874 | * so whenever off >=range, it means no safe bytes from this pointer. | |
2875 | * When comparing old->off <= cur->off, it means that older code | |
2876 | * went with smaller offset and that offset was later | |
2877 | * used to figure out the safe range after 'if (ptr > data_end)' check | |
2878 | * Say, 'old' state was explored like: | |
2879 | * ... R3(off=0, r=0) | |
2880 | * R4 = R3 + 20 | |
2881 | * ... now R4(off=20,r=0) <-- here | |
2882 | * if (R4 > data_end) | |
2883 | * ... R4(off=20,r=20), R3(off=0,r=20) and R3 can be used to access. | |
2884 | * ... the code further went all the way to bpf_exit. | |
2885 | * Now the 'cur' state at the mark 'here' has R4(off=30,r=0). | |
2886 | * old_R4(off=20,r=0) equal to cur_R4(off=30,r=0), since if the verifier | |
2887 | * goes further, such cur_R4 will give larger safe packet range after | |
2888 | * 'if (R4 > data_end)' and all further insn were already good with r=20, | |
2889 | * so they will be good with r=30 and we can prune the search. | |
2890 | */ | |
1ad2f583 | 2891 | if (!env->strict_alignment && old->off <= cur->off && |
969bf05e AS |
2892 | old->off >= old->range && cur->off >= cur->range) |
2893 | return true; | |
2894 | ||
2895 | return false; | |
2896 | } | |
2897 | ||
f1bca824 AS |
2898 | /* compare two verifier states |
2899 | * | |
2900 | * all states stored in state_list are known to be valid, since | |
2901 | * verifier reached 'bpf_exit' instruction through them | |
2902 | * | |
2903 | * this function is called when verifier exploring different branches of | |
2904 | * execution popped from the state stack. If it sees an old state that has | |
2905 | * more strict register state and more strict stack state then this execution | |
2906 | * branch doesn't need to be explored further, since verifier already | |
2907 | * concluded that more strict state leads to valid finish. | |
2908 | * | |
2909 | * Therefore two states are equivalent if register state is more conservative | |
2910 | * and explored stack state is more conservative than the current one. | |
2911 | * Example: | |
2912 | * explored current | |
2913 | * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC) | |
2914 | * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC) | |
2915 | * | |
2916 | * In other words if current stack state (one being explored) has more | |
2917 | * valid slots than old one that already passed validation, it means | |
2918 | * the verifier can stop exploring and conclude that current state is valid too | |
2919 | * | |
2920 | * Similarly with registers. If explored state has register type as invalid | |
2921 | * whereas register type in current state is meaningful, it means that | |
2922 | * the current state will reach 'bpf_exit' instruction safely | |
2923 | */ | |
48461135 JB |
2924 | static bool states_equal(struct bpf_verifier_env *env, |
2925 | struct bpf_verifier_state *old, | |
58e2af8b | 2926 | struct bpf_verifier_state *cur) |
f1bca824 | 2927 | { |
e2d2afe1 | 2928 | bool varlen_map_access = env->varlen_map_value_access; |
58e2af8b | 2929 | struct bpf_reg_state *rold, *rcur; |
f1bca824 AS |
2930 | int i; |
2931 | ||
2932 | for (i = 0; i < MAX_BPF_REG; i++) { | |
1a0dc1ac AS |
2933 | rold = &old->regs[i]; |
2934 | rcur = &cur->regs[i]; | |
2935 | ||
2936 | if (memcmp(rold, rcur, sizeof(*rold)) == 0) | |
2937 | continue; | |
2938 | ||
48461135 JB |
2939 | /* If the ranges were not the same, but everything else was and |
2940 | * we didn't do a variable access into a map then we are a-ok. | |
2941 | */ | |
e2d2afe1 | 2942 | if (!varlen_map_access && |
d2a4dd37 | 2943 | memcmp(rold, rcur, offsetofend(struct bpf_reg_state, id)) == 0) |
48461135 JB |
2944 | continue; |
2945 | ||
e2d2afe1 JB |
2946 | /* If we didn't map access then again we don't care about the |
2947 | * mismatched range values and it's ok if our old type was | |
2948 | * UNKNOWN and we didn't go to a NOT_INIT'ed reg. | |
2949 | */ | |
1a0dc1ac | 2950 | if (rold->type == NOT_INIT || |
e2d2afe1 JB |
2951 | (!varlen_map_access && rold->type == UNKNOWN_VALUE && |
2952 | rcur->type != NOT_INIT)) | |
1a0dc1ac AS |
2953 | continue; |
2954 | ||
3c2ce60b DB |
2955 | /* Don't care about the reg->id in this case. */ |
2956 | if (rold->type == PTR_TO_MAP_VALUE_OR_NULL && | |
2957 | rcur->type == PTR_TO_MAP_VALUE_OR_NULL && | |
2958 | rold->map_ptr == rcur->map_ptr) | |
2959 | continue; | |
2960 | ||
969bf05e | 2961 | if (rold->type == PTR_TO_PACKET && rcur->type == PTR_TO_PACKET && |
1ad2f583 | 2962 | compare_ptrs_to_packet(env, rold, rcur)) |
969bf05e AS |
2963 | continue; |
2964 | ||
1a0dc1ac | 2965 | return false; |
f1bca824 AS |
2966 | } |
2967 | ||
2968 | for (i = 0; i < MAX_BPF_STACK; i++) { | |
9c399760 AS |
2969 | if (old->stack_slot_type[i] == STACK_INVALID) |
2970 | continue; | |
2971 | if (old->stack_slot_type[i] != cur->stack_slot_type[i]) | |
2972 | /* Ex: old explored (safe) state has STACK_SPILL in | |
2973 | * this stack slot, but current has has STACK_MISC -> | |
2974 | * this verifier states are not equivalent, | |
2975 | * return false to continue verification of this path | |
2976 | */ | |
f1bca824 | 2977 | return false; |
9c399760 AS |
2978 | if (i % BPF_REG_SIZE) |
2979 | continue; | |
d25da6ca DB |
2980 | if (old->stack_slot_type[i] != STACK_SPILL) |
2981 | continue; | |
9c399760 AS |
2982 | if (memcmp(&old->spilled_regs[i / BPF_REG_SIZE], |
2983 | &cur->spilled_regs[i / BPF_REG_SIZE], | |
2984 | sizeof(old->spilled_regs[0]))) | |
2985 | /* when explored and current stack slot types are | |
2986 | * the same, check that stored pointers types | |
2987 | * are the same as well. | |
2988 | * Ex: explored safe path could have stored | |
58e2af8b | 2989 | * (bpf_reg_state) {.type = PTR_TO_STACK, .imm = -8} |
9c399760 | 2990 | * but current path has stored: |
58e2af8b | 2991 | * (bpf_reg_state) {.type = PTR_TO_STACK, .imm = -16} |
9c399760 AS |
2992 | * such verifier states are not equivalent. |
2993 | * return false to continue verification of this path | |
2994 | */ | |
2995 | return false; | |
2996 | else | |
2997 | continue; | |
f1bca824 AS |
2998 | } |
2999 | return true; | |
3000 | } | |
3001 | ||
58e2af8b | 3002 | static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) |
f1bca824 | 3003 | { |
58e2af8b JK |
3004 | struct bpf_verifier_state_list *new_sl; |
3005 | struct bpf_verifier_state_list *sl; | |
f1bca824 AS |
3006 | |
3007 | sl = env->explored_states[insn_idx]; | |
3008 | if (!sl) | |
3009 | /* this 'insn_idx' instruction wasn't marked, so we will not | |
3010 | * be doing state search here | |
3011 | */ | |
3012 | return 0; | |
3013 | ||
3014 | while (sl != STATE_LIST_MARK) { | |
48461135 | 3015 | if (states_equal(env, &sl->state, &env->cur_state)) |
f1bca824 AS |
3016 | /* reached equivalent register/stack state, |
3017 | * prune the search | |
3018 | */ | |
3019 | return 1; | |
3020 | sl = sl->next; | |
3021 | } | |
3022 | ||
3023 | /* there were no equivalent states, remember current one. | |
3024 | * technically the current state is not proven to be safe yet, | |
3025 | * but it will either reach bpf_exit (which means it's safe) or | |
3026 | * it will be rejected. Since there are no loops, we won't be | |
3027 | * seeing this 'insn_idx' instruction again on the way to bpf_exit | |
3028 | */ | |
58e2af8b | 3029 | new_sl = kmalloc(sizeof(struct bpf_verifier_state_list), GFP_USER); |
f1bca824 AS |
3030 | if (!new_sl) |
3031 | return -ENOMEM; | |
3032 | ||
3033 | /* add new state to the head of linked list */ | |
3034 | memcpy(&new_sl->state, &env->cur_state, sizeof(env->cur_state)); | |
3035 | new_sl->next = env->explored_states[insn_idx]; | |
3036 | env->explored_states[insn_idx] = new_sl; | |
3037 | return 0; | |
3038 | } | |
3039 | ||
13a27dfc JK |
3040 | static int ext_analyzer_insn_hook(struct bpf_verifier_env *env, |
3041 | int insn_idx, int prev_insn_idx) | |
3042 | { | |
3043 | if (!env->analyzer_ops || !env->analyzer_ops->insn_hook) | |
3044 | return 0; | |
3045 | ||
3046 | return env->analyzer_ops->insn_hook(env, insn_idx, prev_insn_idx); | |
3047 | } | |
3048 | ||
58e2af8b | 3049 | static int do_check(struct bpf_verifier_env *env) |
17a52670 | 3050 | { |
58e2af8b | 3051 | struct bpf_verifier_state *state = &env->cur_state; |
17a52670 | 3052 | struct bpf_insn *insns = env->prog->insnsi; |
58e2af8b | 3053 | struct bpf_reg_state *regs = state->regs; |
17a52670 AS |
3054 | int insn_cnt = env->prog->len; |
3055 | int insn_idx, prev_insn_idx = 0; | |
3056 | int insn_processed = 0; | |
3057 | bool do_print_state = false; | |
3058 | ||
3059 | init_reg_state(regs); | |
3060 | insn_idx = 0; | |
48461135 | 3061 | env->varlen_map_value_access = false; |
17a52670 AS |
3062 | for (;;) { |
3063 | struct bpf_insn *insn; | |
3064 | u8 class; | |
3065 | int err; | |
3066 | ||
3067 | if (insn_idx >= insn_cnt) { | |
3068 | verbose("invalid insn idx %d insn_cnt %d\n", | |
3069 | insn_idx, insn_cnt); | |
3070 | return -EFAULT; | |
3071 | } | |
3072 | ||
3073 | insn = &insns[insn_idx]; | |
3074 | class = BPF_CLASS(insn->code); | |
3075 | ||
07016151 | 3076 | if (++insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) { |
bc1750f3 | 3077 | verbose("BPF program is too large. Processed %d insn\n", |
17a52670 AS |
3078 | insn_processed); |
3079 | return -E2BIG; | |
3080 | } | |
3081 | ||
f1bca824 AS |
3082 | err = is_state_visited(env, insn_idx); |
3083 | if (err < 0) | |
3084 | return err; | |
3085 | if (err == 1) { | |
3086 | /* found equivalent state, can prune the search */ | |
3087 | if (log_level) { | |
3088 | if (do_print_state) | |
3089 | verbose("\nfrom %d to %d: safe\n", | |
3090 | prev_insn_idx, insn_idx); | |
3091 | else | |
3092 | verbose("%d: safe\n", insn_idx); | |
3093 | } | |
3094 | goto process_bpf_exit; | |
3095 | } | |
3096 | ||
3c2ce60b DB |
3097 | if (need_resched()) |
3098 | cond_resched(); | |
3099 | ||
c5fc9692 DM |
3100 | if (log_level > 1 || (log_level && do_print_state)) { |
3101 | if (log_level > 1) | |
3102 | verbose("%d:", insn_idx); | |
3103 | else | |
3104 | verbose("\nfrom %d to %d:", | |
3105 | prev_insn_idx, insn_idx); | |
1a0dc1ac | 3106 | print_verifier_state(&env->cur_state); |
17a52670 AS |
3107 | do_print_state = false; |
3108 | } | |
3109 | ||
3110 | if (log_level) { | |
3111 | verbose("%d: ", insn_idx); | |
0d0e5769 | 3112 | print_bpf_insn(env, insn); |
17a52670 AS |
3113 | } |
3114 | ||
13a27dfc JK |
3115 | err = ext_analyzer_insn_hook(env, insn_idx, prev_insn_idx); |
3116 | if (err) | |
3117 | return err; | |
3118 | ||
17a52670 | 3119 | if (class == BPF_ALU || class == BPF_ALU64) { |
1be7f75d | 3120 | err = check_alu_op(env, insn); |
17a52670 AS |
3121 | if (err) |
3122 | return err; | |
3123 | ||
3124 | } else if (class == BPF_LDX) { | |
3df126f3 | 3125 | enum bpf_reg_type *prev_src_type, src_reg_type; |
9bac3d6d AS |
3126 | |
3127 | /* check for reserved fields is already done */ | |
3128 | ||
17a52670 AS |
3129 | /* check src operand */ |
3130 | err = check_reg_arg(regs, insn->src_reg, SRC_OP); | |
3131 | if (err) | |
3132 | return err; | |
3133 | ||
3134 | err = check_reg_arg(regs, insn->dst_reg, DST_OP_NO_MARK); | |
3135 | if (err) | |
3136 | return err; | |
3137 | ||
725f9dcd AS |
3138 | src_reg_type = regs[insn->src_reg].type; |
3139 | ||
17a52670 AS |
3140 | /* check that memory (src_reg + off) is readable, |
3141 | * the state of dst_reg will be updated by this func | |
3142 | */ | |
31fd8581 | 3143 | err = check_mem_access(env, insn_idx, insn->src_reg, insn->off, |
17a52670 AS |
3144 | BPF_SIZE(insn->code), BPF_READ, |
3145 | insn->dst_reg); | |
3146 | if (err) | |
3147 | return err; | |
3148 | ||
3df126f3 JK |
3149 | prev_src_type = &env->insn_aux_data[insn_idx].ptr_type; |
3150 | ||
3151 | if (*prev_src_type == NOT_INIT) { | |
9bac3d6d AS |
3152 | /* saw a valid insn |
3153 | * dst_reg = *(u32 *)(src_reg + off) | |
3df126f3 | 3154 | * save type to validate intersecting paths |
9bac3d6d | 3155 | */ |
3df126f3 | 3156 | *prev_src_type = src_reg_type; |
9bac3d6d | 3157 | |
3df126f3 | 3158 | } else if (src_reg_type != *prev_src_type && |
9bac3d6d | 3159 | (src_reg_type == PTR_TO_CTX || |
3df126f3 | 3160 | *prev_src_type == PTR_TO_CTX)) { |
9bac3d6d AS |
3161 | /* ABuser program is trying to use the same insn |
3162 | * dst_reg = *(u32*) (src_reg + off) | |
3163 | * with different pointer types: | |
3164 | * src_reg == ctx in one branch and | |
3165 | * src_reg == stack|map in some other branch. | |
3166 | * Reject it. | |
3167 | */ | |
3168 | verbose("same insn cannot be used with different pointers\n"); | |
3169 | return -EINVAL; | |
3170 | } | |
3171 | ||
17a52670 | 3172 | } else if (class == BPF_STX) { |
3df126f3 | 3173 | enum bpf_reg_type *prev_dst_type, dst_reg_type; |
d691f9e8 | 3174 | |
17a52670 | 3175 | if (BPF_MODE(insn->code) == BPF_XADD) { |
31fd8581 | 3176 | err = check_xadd(env, insn_idx, insn); |
17a52670 AS |
3177 | if (err) |
3178 | return err; | |
3179 | insn_idx++; | |
3180 | continue; | |
3181 | } | |
3182 | ||
17a52670 AS |
3183 | /* check src1 operand */ |
3184 | err = check_reg_arg(regs, insn->src_reg, SRC_OP); | |
3185 | if (err) | |
3186 | return err; | |
3187 | /* check src2 operand */ | |
3188 | err = check_reg_arg(regs, insn->dst_reg, SRC_OP); | |
3189 | if (err) | |
3190 | return err; | |
3191 | ||
d691f9e8 AS |
3192 | dst_reg_type = regs[insn->dst_reg].type; |
3193 | ||
17a52670 | 3194 | /* check that memory (dst_reg + off) is writeable */ |
31fd8581 | 3195 | err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off, |
17a52670 AS |
3196 | BPF_SIZE(insn->code), BPF_WRITE, |
3197 | insn->src_reg); | |
3198 | if (err) | |
3199 | return err; | |
3200 | ||
3df126f3 JK |
3201 | prev_dst_type = &env->insn_aux_data[insn_idx].ptr_type; |
3202 | ||
3203 | if (*prev_dst_type == NOT_INIT) { | |
3204 | *prev_dst_type = dst_reg_type; | |
3205 | } else if (dst_reg_type != *prev_dst_type && | |
d691f9e8 | 3206 | (dst_reg_type == PTR_TO_CTX || |
3df126f3 | 3207 | *prev_dst_type == PTR_TO_CTX)) { |
d691f9e8 AS |
3208 | verbose("same insn cannot be used with different pointers\n"); |
3209 | return -EINVAL; | |
3210 | } | |
3211 | ||
17a52670 AS |
3212 | } else if (class == BPF_ST) { |
3213 | if (BPF_MODE(insn->code) != BPF_MEM || | |
3214 | insn->src_reg != BPF_REG_0) { | |
3215 | verbose("BPF_ST uses reserved fields\n"); | |
3216 | return -EINVAL; | |
3217 | } | |
3218 | /* check src operand */ | |
3219 | err = check_reg_arg(regs, insn->dst_reg, SRC_OP); | |
3220 | if (err) | |
3221 | return err; | |
3222 | ||
3223 | /* check that memory (dst_reg + off) is writeable */ | |
31fd8581 | 3224 | err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off, |
17a52670 AS |
3225 | BPF_SIZE(insn->code), BPF_WRITE, |
3226 | -1); | |
3227 | if (err) | |
3228 | return err; | |
3229 | ||
3230 | } else if (class == BPF_JMP) { | |
3231 | u8 opcode = BPF_OP(insn->code); | |
3232 | ||
3233 | if (opcode == BPF_CALL) { | |
3234 | if (BPF_SRC(insn->code) != BPF_K || | |
3235 | insn->off != 0 || | |
3236 | insn->src_reg != BPF_REG_0 || | |
3237 | insn->dst_reg != BPF_REG_0) { | |
3238 | verbose("BPF_CALL uses reserved fields\n"); | |
3239 | return -EINVAL; | |
3240 | } | |
3241 | ||
81ed18ab | 3242 | err = check_call(env, insn->imm, insn_idx); |
17a52670 AS |
3243 | if (err) |
3244 | return err; | |
3245 | ||
3246 | } else if (opcode == BPF_JA) { | |
3247 | if (BPF_SRC(insn->code) != BPF_K || | |
3248 | insn->imm != 0 || | |
3249 | insn->src_reg != BPF_REG_0 || | |
3250 | insn->dst_reg != BPF_REG_0) { | |
3251 | verbose("BPF_JA uses reserved fields\n"); | |
3252 | return -EINVAL; | |
3253 | } | |
3254 | ||
3255 | insn_idx += insn->off + 1; | |
3256 | continue; | |
3257 | ||
3258 | } else if (opcode == BPF_EXIT) { | |
3259 | if (BPF_SRC(insn->code) != BPF_K || | |
3260 | insn->imm != 0 || | |
3261 | insn->src_reg != BPF_REG_0 || | |
3262 | insn->dst_reg != BPF_REG_0) { | |
3263 | verbose("BPF_EXIT uses reserved fields\n"); | |
3264 | return -EINVAL; | |
3265 | } | |
3266 | ||
3267 | /* eBPF calling convetion is such that R0 is used | |
3268 | * to return the value from eBPF program. | |
3269 | * Make sure that it's readable at this time | |
3270 | * of bpf_exit, which means that program wrote | |
3271 | * something into it earlier | |
3272 | */ | |
3273 | err = check_reg_arg(regs, BPF_REG_0, SRC_OP); | |
3274 | if (err) | |
3275 | return err; | |
3276 | ||
1be7f75d AS |
3277 | if (is_pointer_value(env, BPF_REG_0)) { |
3278 | verbose("R0 leaks addr as return value\n"); | |
3279 | return -EACCES; | |
3280 | } | |
3281 | ||
f1bca824 | 3282 | process_bpf_exit: |
17a52670 AS |
3283 | insn_idx = pop_stack(env, &prev_insn_idx); |
3284 | if (insn_idx < 0) { | |
3285 | break; | |
3286 | } else { | |
3287 | do_print_state = true; | |
3288 | continue; | |
3289 | } | |
3290 | } else { | |
3291 | err = check_cond_jmp_op(env, insn, &insn_idx); | |
3292 | if (err) | |
3293 | return err; | |
3294 | } | |
3295 | } else if (class == BPF_LD) { | |
3296 | u8 mode = BPF_MODE(insn->code); | |
3297 | ||
3298 | if (mode == BPF_ABS || mode == BPF_IND) { | |
ddd872bc AS |
3299 | err = check_ld_abs(env, insn); |
3300 | if (err) | |
3301 | return err; | |
3302 | ||
17a52670 AS |
3303 | } else if (mode == BPF_IMM) { |
3304 | err = check_ld_imm(env, insn); | |
3305 | if (err) | |
3306 | return err; | |
3307 | ||
3308 | insn_idx++; | |
3309 | } else { | |
3310 | verbose("invalid BPF_LD mode\n"); | |
3311 | return -EINVAL; | |
3312 | } | |
48461135 | 3313 | reset_reg_range_values(regs, insn->dst_reg); |
17a52670 AS |
3314 | } else { |
3315 | verbose("unknown insn class %d\n", class); | |
3316 | return -EINVAL; | |
3317 | } | |
3318 | ||
3319 | insn_idx++; | |
3320 | } | |
3321 | ||
8726679a AS |
3322 | verbose("processed %d insns, stack depth %d\n", |
3323 | insn_processed, env->prog->aux->stack_depth); | |
17a52670 AS |
3324 | return 0; |
3325 | } | |
3326 | ||
56f668df MKL |
3327 | static int check_map_prealloc(struct bpf_map *map) |
3328 | { | |
3329 | return (map->map_type != BPF_MAP_TYPE_HASH && | |
bcc6b1b7 MKL |
3330 | map->map_type != BPF_MAP_TYPE_PERCPU_HASH && |
3331 | map->map_type != BPF_MAP_TYPE_HASH_OF_MAPS) || | |
56f668df MKL |
3332 | !(map->map_flags & BPF_F_NO_PREALLOC); |
3333 | } | |
3334 | ||
fdc15d38 AS |
3335 | static int check_map_prog_compatibility(struct bpf_map *map, |
3336 | struct bpf_prog *prog) | |
3337 | ||
3338 | { | |
56f668df MKL |
3339 | /* Make sure that BPF_PROG_TYPE_PERF_EVENT programs only use |
3340 | * preallocated hash maps, since doing memory allocation | |
3341 | * in overflow_handler can crash depending on where nmi got | |
3342 | * triggered. | |
3343 | */ | |
3344 | if (prog->type == BPF_PROG_TYPE_PERF_EVENT) { | |
3345 | if (!check_map_prealloc(map)) { | |
3346 | verbose("perf_event programs can only use preallocated hash map\n"); | |
3347 | return -EINVAL; | |
3348 | } | |
3349 | if (map->inner_map_meta && | |
3350 | !check_map_prealloc(map->inner_map_meta)) { | |
3351 | verbose("perf_event programs can only use preallocated inner hash map\n"); | |
3352 | return -EINVAL; | |
3353 | } | |
fdc15d38 AS |
3354 | } |
3355 | return 0; | |
3356 | } | |
3357 | ||
0246e64d AS |
3358 | /* look for pseudo eBPF instructions that access map FDs and |
3359 | * replace them with actual map pointers | |
3360 | */ | |
58e2af8b | 3361 | static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env) |
0246e64d AS |
3362 | { |
3363 | struct bpf_insn *insn = env->prog->insnsi; | |
3364 | int insn_cnt = env->prog->len; | |
fdc15d38 | 3365 | int i, j, err; |
0246e64d | 3366 | |
f1f7714e | 3367 | err = bpf_prog_calc_tag(env->prog); |
aafe6ae9 DB |
3368 | if (err) |
3369 | return err; | |
3370 | ||
0246e64d | 3371 | for (i = 0; i < insn_cnt; i++, insn++) { |
9bac3d6d | 3372 | if (BPF_CLASS(insn->code) == BPF_LDX && |
d691f9e8 | 3373 | (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0)) { |
9bac3d6d AS |
3374 | verbose("BPF_LDX uses reserved fields\n"); |
3375 | return -EINVAL; | |
3376 | } | |
3377 | ||
d691f9e8 AS |
3378 | if (BPF_CLASS(insn->code) == BPF_STX && |
3379 | ((BPF_MODE(insn->code) != BPF_MEM && | |
3380 | BPF_MODE(insn->code) != BPF_XADD) || insn->imm != 0)) { | |
3381 | verbose("BPF_STX uses reserved fields\n"); | |
3382 | return -EINVAL; | |
3383 | } | |
3384 | ||
0246e64d AS |
3385 | if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) { |
3386 | struct bpf_map *map; | |
3387 | struct fd f; | |
3388 | ||
3389 | if (i == insn_cnt - 1 || insn[1].code != 0 || | |
3390 | insn[1].dst_reg != 0 || insn[1].src_reg != 0 || | |
3391 | insn[1].off != 0) { | |
3392 | verbose("invalid bpf_ld_imm64 insn\n"); | |
3393 | return -EINVAL; | |
3394 | } | |
3395 | ||
3396 | if (insn->src_reg == 0) | |
3397 | /* valid generic load 64-bit imm */ | |
3398 | goto next_insn; | |
3399 | ||
3400 | if (insn->src_reg != BPF_PSEUDO_MAP_FD) { | |
3401 | verbose("unrecognized bpf_ld_imm64 insn\n"); | |
3402 | return -EINVAL; | |
3403 | } | |
3404 | ||
3405 | f = fdget(insn->imm); | |
c2101297 | 3406 | map = __bpf_map_get(f); |
0246e64d AS |
3407 | if (IS_ERR(map)) { |
3408 | verbose("fd %d is not pointing to valid bpf_map\n", | |
3409 | insn->imm); | |
0246e64d AS |
3410 | return PTR_ERR(map); |
3411 | } | |
3412 | ||
fdc15d38 AS |
3413 | err = check_map_prog_compatibility(map, env->prog); |
3414 | if (err) { | |
3415 | fdput(f); | |
3416 | return err; | |
3417 | } | |
3418 | ||
0246e64d AS |
3419 | /* store map pointer inside BPF_LD_IMM64 instruction */ |
3420 | insn[0].imm = (u32) (unsigned long) map; | |
3421 | insn[1].imm = ((u64) (unsigned long) map) >> 32; | |
3422 | ||
3423 | /* check whether we recorded this map already */ | |
3424 | for (j = 0; j < env->used_map_cnt; j++) | |
3425 | if (env->used_maps[j] == map) { | |
3426 | fdput(f); | |
3427 | goto next_insn; | |
3428 | } | |
3429 | ||
3430 | if (env->used_map_cnt >= MAX_USED_MAPS) { | |
3431 | fdput(f); | |
3432 | return -E2BIG; | |
3433 | } | |
3434 | ||
0246e64d AS |
3435 | /* hold the map. If the program is rejected by verifier, |
3436 | * the map will be released by release_maps() or it | |
3437 | * will be used by the valid program until it's unloaded | |
3438 | * and all maps are released in free_bpf_prog_info() | |
3439 | */ | |
92117d84 AS |
3440 | map = bpf_map_inc(map, false); |
3441 | if (IS_ERR(map)) { | |
3442 | fdput(f); | |
3443 | return PTR_ERR(map); | |
3444 | } | |
3445 | env->used_maps[env->used_map_cnt++] = map; | |
3446 | ||
0246e64d AS |
3447 | fdput(f); |
3448 | next_insn: | |
3449 | insn++; | |
3450 | i++; | |
3451 | } | |
3452 | } | |
3453 | ||
3454 | /* now all pseudo BPF_LD_IMM64 instructions load valid | |
3455 | * 'struct bpf_map *' into a register instead of user map_fd. | |
3456 | * These pointers will be used later by verifier to validate map access. | |
3457 | */ | |
3458 | return 0; | |
3459 | } | |
3460 | ||
3461 | /* drop refcnt of maps used by the rejected program */ | |
58e2af8b | 3462 | static void release_maps(struct bpf_verifier_env *env) |
0246e64d AS |
3463 | { |
3464 | int i; | |
3465 | ||
3466 | for (i = 0; i < env->used_map_cnt; i++) | |
3467 | bpf_map_put(env->used_maps[i]); | |
3468 | } | |
3469 | ||
3470 | /* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */ | |
58e2af8b | 3471 | static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env) |
0246e64d AS |
3472 | { |
3473 | struct bpf_insn *insn = env->prog->insnsi; | |
3474 | int insn_cnt = env->prog->len; | |
3475 | int i; | |
3476 | ||
3477 | for (i = 0; i < insn_cnt; i++, insn++) | |
3478 | if (insn->code == (BPF_LD | BPF_IMM | BPF_DW)) | |
3479 | insn->src_reg = 0; | |
3480 | } | |
3481 | ||
8041902d AS |
3482 | /* single env->prog->insni[off] instruction was replaced with the range |
3483 | * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying | |
3484 | * [0, off) and [off, end) to new locations, so the patched range stays zero | |
3485 | */ | |
3486 | static int adjust_insn_aux_data(struct bpf_verifier_env *env, u32 prog_len, | |
3487 | u32 off, u32 cnt) | |
3488 | { | |
3489 | struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data; | |
3490 | ||
3491 | if (cnt == 1) | |
3492 | return 0; | |
3493 | new_data = vzalloc(sizeof(struct bpf_insn_aux_data) * prog_len); | |
3494 | if (!new_data) | |
3495 | return -ENOMEM; | |
3496 | memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off); | |
3497 | memcpy(new_data + off + cnt - 1, old_data + off, | |
3498 | sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1)); | |
3499 | env->insn_aux_data = new_data; | |
3500 | vfree(old_data); | |
3501 | return 0; | |
3502 | } | |
3503 | ||
3504 | static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off, | |
3505 | const struct bpf_insn *patch, u32 len) | |
3506 | { | |
3507 | struct bpf_prog *new_prog; | |
3508 | ||
3509 | new_prog = bpf_patch_insn_single(env->prog, off, patch, len); | |
3510 | if (!new_prog) | |
3511 | return NULL; | |
3512 | if (adjust_insn_aux_data(env, new_prog->len, off, len)) | |
3513 | return NULL; | |
3514 | return new_prog; | |
3515 | } | |
3516 | ||
9bac3d6d AS |
3517 | /* convert load instructions that access fields of 'struct __sk_buff' |
3518 | * into sequence of instructions that access fields of 'struct sk_buff' | |
3519 | */ | |
58e2af8b | 3520 | static int convert_ctx_accesses(struct bpf_verifier_env *env) |
9bac3d6d | 3521 | { |
36bbef52 | 3522 | const struct bpf_verifier_ops *ops = env->prog->aux->ops; |
f96da094 | 3523 | int i, cnt, size, ctx_field_size, delta = 0; |
3df126f3 | 3524 | const int insn_cnt = env->prog->len; |
36bbef52 | 3525 | struct bpf_insn insn_buf[16], *insn; |
9bac3d6d | 3526 | struct bpf_prog *new_prog; |
d691f9e8 | 3527 | enum bpf_access_type type; |
f96da094 DB |
3528 | bool is_narrower_load; |
3529 | u32 target_size; | |
9bac3d6d | 3530 | |
36bbef52 DB |
3531 | if (ops->gen_prologue) { |
3532 | cnt = ops->gen_prologue(insn_buf, env->seen_direct_write, | |
3533 | env->prog); | |
3534 | if (cnt >= ARRAY_SIZE(insn_buf)) { | |
3535 | verbose("bpf verifier is misconfigured\n"); | |
3536 | return -EINVAL; | |
3537 | } else if (cnt) { | |
8041902d | 3538 | new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt); |
36bbef52 DB |
3539 | if (!new_prog) |
3540 | return -ENOMEM; | |
8041902d | 3541 | |
36bbef52 | 3542 | env->prog = new_prog; |
3df126f3 | 3543 | delta += cnt - 1; |
36bbef52 DB |
3544 | } |
3545 | } | |
3546 | ||
3547 | if (!ops->convert_ctx_access) | |
9bac3d6d AS |
3548 | return 0; |
3549 | ||
3df126f3 | 3550 | insn = env->prog->insnsi + delta; |
36bbef52 | 3551 | |
9bac3d6d | 3552 | for (i = 0; i < insn_cnt; i++, insn++) { |
62c7989b DB |
3553 | if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) || |
3554 | insn->code == (BPF_LDX | BPF_MEM | BPF_H) || | |
3555 | insn->code == (BPF_LDX | BPF_MEM | BPF_W) || | |
ea2e7ce5 | 3556 | insn->code == (BPF_LDX | BPF_MEM | BPF_DW)) |
d691f9e8 | 3557 | type = BPF_READ; |
62c7989b DB |
3558 | else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) || |
3559 | insn->code == (BPF_STX | BPF_MEM | BPF_H) || | |
3560 | insn->code == (BPF_STX | BPF_MEM | BPF_W) || | |
ea2e7ce5 | 3561 | insn->code == (BPF_STX | BPF_MEM | BPF_DW)) |
d691f9e8 AS |
3562 | type = BPF_WRITE; |
3563 | else | |
9bac3d6d AS |
3564 | continue; |
3565 | ||
8041902d | 3566 | if (env->insn_aux_data[i + delta].ptr_type != PTR_TO_CTX) |
9bac3d6d | 3567 | continue; |
9bac3d6d | 3568 | |
31fd8581 | 3569 | ctx_field_size = env->insn_aux_data[i + delta].ctx_field_size; |
f96da094 | 3570 | size = BPF_LDST_BYTES(insn); |
31fd8581 YS |
3571 | |
3572 | /* If the read access is a narrower load of the field, | |
3573 | * convert to a 4/8-byte load, to minimum program type specific | |
3574 | * convert_ctx_access changes. If conversion is successful, | |
3575 | * we will apply proper mask to the result. | |
3576 | */ | |
f96da094 | 3577 | is_narrower_load = size < ctx_field_size; |
31fd8581 | 3578 | if (is_narrower_load) { |
f96da094 DB |
3579 | u32 off = insn->off; |
3580 | u8 size_code; | |
3581 | ||
3582 | if (type == BPF_WRITE) { | |
3583 | verbose("bpf verifier narrow ctx access misconfigured\n"); | |
3584 | return -EINVAL; | |
3585 | } | |
31fd8581 | 3586 | |
f96da094 | 3587 | size_code = BPF_H; |
31fd8581 YS |
3588 | if (ctx_field_size == 4) |
3589 | size_code = BPF_W; | |
3590 | else if (ctx_field_size == 8) | |
3591 | size_code = BPF_DW; | |
f96da094 | 3592 | |
31fd8581 YS |
3593 | insn->off = off & ~(ctx_field_size - 1); |
3594 | insn->code = BPF_LDX | BPF_MEM | size_code; | |
3595 | } | |
f96da094 DB |
3596 | |
3597 | target_size = 0; | |
3598 | cnt = ops->convert_ctx_access(type, insn, insn_buf, env->prog, | |
3599 | &target_size); | |
3600 | if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) || | |
3601 | (ctx_field_size && !target_size)) { | |
9bac3d6d AS |
3602 | verbose("bpf verifier is misconfigured\n"); |
3603 | return -EINVAL; | |
3604 | } | |
f96da094 DB |
3605 | |
3606 | if (is_narrower_load && size < target_size) { | |
31fd8581 YS |
3607 | if (ctx_field_size <= 4) |
3608 | insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg, | |
f96da094 | 3609 | (1 << size * 8) - 1); |
31fd8581 YS |
3610 | else |
3611 | insn_buf[cnt++] = BPF_ALU64_IMM(BPF_AND, insn->dst_reg, | |
f96da094 | 3612 | (1 << size * 8) - 1); |
31fd8581 | 3613 | } |
9bac3d6d | 3614 | |
8041902d | 3615 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); |
9bac3d6d AS |
3616 | if (!new_prog) |
3617 | return -ENOMEM; | |
3618 | ||
3df126f3 | 3619 | delta += cnt - 1; |
9bac3d6d AS |
3620 | |
3621 | /* keep walking new program and skip insns we just inserted */ | |
3622 | env->prog = new_prog; | |
3df126f3 | 3623 | insn = new_prog->insnsi + i + delta; |
9bac3d6d AS |
3624 | } |
3625 | ||
3626 | return 0; | |
3627 | } | |
3628 | ||
79741b3b | 3629 | /* fixup insn->imm field of bpf_call instructions |
81ed18ab | 3630 | * and inline eligible helpers as explicit sequence of BPF instructions |
e245c5c6 AS |
3631 | * |
3632 | * this function is called after eBPF program passed verification | |
3633 | */ | |
79741b3b | 3634 | static int fixup_bpf_calls(struct bpf_verifier_env *env) |
e245c5c6 | 3635 | { |
79741b3b AS |
3636 | struct bpf_prog *prog = env->prog; |
3637 | struct bpf_insn *insn = prog->insnsi; | |
e245c5c6 | 3638 | const struct bpf_func_proto *fn; |
79741b3b | 3639 | const int insn_cnt = prog->len; |
81ed18ab AS |
3640 | struct bpf_insn insn_buf[16]; |
3641 | struct bpf_prog *new_prog; | |
3642 | struct bpf_map *map_ptr; | |
3643 | int i, cnt, delta = 0; | |
e245c5c6 | 3644 | |
79741b3b AS |
3645 | for (i = 0; i < insn_cnt; i++, insn++) { |
3646 | if (insn->code != (BPF_JMP | BPF_CALL)) | |
3647 | continue; | |
e245c5c6 | 3648 | |
79741b3b AS |
3649 | if (insn->imm == BPF_FUNC_get_route_realm) |
3650 | prog->dst_needed = 1; | |
3651 | if (insn->imm == BPF_FUNC_get_prandom_u32) | |
3652 | bpf_user_rnd_init_once(); | |
79741b3b | 3653 | if (insn->imm == BPF_FUNC_tail_call) { |
7b9f6da1 DM |
3654 | /* If we tail call into other programs, we |
3655 | * cannot make any assumptions since they can | |
3656 | * be replaced dynamically during runtime in | |
3657 | * the program array. | |
3658 | */ | |
3659 | prog->cb_access = 1; | |
80a58d02 | 3660 | env->prog->aux->stack_depth = MAX_BPF_STACK; |
7b9f6da1 | 3661 | |
79741b3b AS |
3662 | /* mark bpf_tail_call as different opcode to avoid |
3663 | * conditional branch in the interpeter for every normal | |
3664 | * call and to prevent accidental JITing by JIT compiler | |
3665 | * that doesn't support bpf_tail_call yet | |
e245c5c6 | 3666 | */ |
79741b3b | 3667 | insn->imm = 0; |
71189fa9 | 3668 | insn->code = BPF_JMP | BPF_TAIL_CALL; |
79741b3b AS |
3669 | continue; |
3670 | } | |
e245c5c6 | 3671 | |
81ed18ab AS |
3672 | if (ebpf_jit_enabled() && insn->imm == BPF_FUNC_map_lookup_elem) { |
3673 | map_ptr = env->insn_aux_data[i + delta].map_ptr; | |
fad73a1a MKL |
3674 | if (map_ptr == BPF_MAP_PTR_POISON || |
3675 | !map_ptr->ops->map_gen_lookup) | |
81ed18ab AS |
3676 | goto patch_call_imm; |
3677 | ||
3678 | cnt = map_ptr->ops->map_gen_lookup(map_ptr, insn_buf); | |
3679 | if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) { | |
3680 | verbose("bpf verifier is misconfigured\n"); | |
3681 | return -EINVAL; | |
3682 | } | |
3683 | ||
3684 | new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, | |
3685 | cnt); | |
3686 | if (!new_prog) | |
3687 | return -ENOMEM; | |
3688 | ||
3689 | delta += cnt - 1; | |
3690 | ||
3691 | /* keep walking new program and skip insns we just inserted */ | |
3692 | env->prog = prog = new_prog; | |
3693 | insn = new_prog->insnsi + i + delta; | |
3694 | continue; | |
3695 | } | |
3696 | ||
3697 | patch_call_imm: | |
79741b3b AS |
3698 | fn = prog->aux->ops->get_func_proto(insn->imm); |
3699 | /* all functions that have prototype and verifier allowed | |
3700 | * programs to call them, must be real in-kernel functions | |
3701 | */ | |
3702 | if (!fn->func) { | |
3703 | verbose("kernel subsystem misconfigured func %s#%d\n", | |
3704 | func_id_name(insn->imm), insn->imm); | |
3705 | return -EFAULT; | |
e245c5c6 | 3706 | } |
79741b3b | 3707 | insn->imm = fn->func - __bpf_call_base; |
e245c5c6 | 3708 | } |
e245c5c6 | 3709 | |
79741b3b AS |
3710 | return 0; |
3711 | } | |
e245c5c6 | 3712 | |
58e2af8b | 3713 | static void free_states(struct bpf_verifier_env *env) |
f1bca824 | 3714 | { |
58e2af8b | 3715 | struct bpf_verifier_state_list *sl, *sln; |
f1bca824 AS |
3716 | int i; |
3717 | ||
3718 | if (!env->explored_states) | |
3719 | return; | |
3720 | ||
3721 | for (i = 0; i < env->prog->len; i++) { | |
3722 | sl = env->explored_states[i]; | |
3723 | ||
3724 | if (sl) | |
3725 | while (sl != STATE_LIST_MARK) { | |
3726 | sln = sl->next; | |
3727 | kfree(sl); | |
3728 | sl = sln; | |
3729 | } | |
3730 | } | |
3731 | ||
3732 | kfree(env->explored_states); | |
3733 | } | |
3734 | ||
9bac3d6d | 3735 | int bpf_check(struct bpf_prog **prog, union bpf_attr *attr) |
51580e79 | 3736 | { |
cbd35700 | 3737 | char __user *log_ubuf = NULL; |
58e2af8b | 3738 | struct bpf_verifier_env *env; |
51580e79 AS |
3739 | int ret = -EINVAL; |
3740 | ||
58e2af8b | 3741 | /* 'struct bpf_verifier_env' can be global, but since it's not small, |
cbd35700 AS |
3742 | * allocate/free it every time bpf_check() is called |
3743 | */ | |
58e2af8b | 3744 | env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL); |
cbd35700 AS |
3745 | if (!env) |
3746 | return -ENOMEM; | |
3747 | ||
3df126f3 JK |
3748 | env->insn_aux_data = vzalloc(sizeof(struct bpf_insn_aux_data) * |
3749 | (*prog)->len); | |
3750 | ret = -ENOMEM; | |
3751 | if (!env->insn_aux_data) | |
3752 | goto err_free_env; | |
9bac3d6d | 3753 | env->prog = *prog; |
0246e64d | 3754 | |
cbd35700 AS |
3755 | /* grab the mutex to protect few globals used by verifier */ |
3756 | mutex_lock(&bpf_verifier_lock); | |
3757 | ||
3758 | if (attr->log_level || attr->log_buf || attr->log_size) { | |
3759 | /* user requested verbose verifier output | |
3760 | * and supplied buffer to store the verification trace | |
3761 | */ | |
3762 | log_level = attr->log_level; | |
3763 | log_ubuf = (char __user *) (unsigned long) attr->log_buf; | |
3764 | log_size = attr->log_size; | |
3765 | log_len = 0; | |
3766 | ||
3767 | ret = -EINVAL; | |
3768 | /* log_* values have to be sane */ | |
3769 | if (log_size < 128 || log_size > UINT_MAX >> 8 || | |
3770 | log_level == 0 || log_ubuf == NULL) | |
3df126f3 | 3771 | goto err_unlock; |
cbd35700 AS |
3772 | |
3773 | ret = -ENOMEM; | |
3774 | log_buf = vmalloc(log_size); | |
3775 | if (!log_buf) | |
3df126f3 | 3776 | goto err_unlock; |
cbd35700 AS |
3777 | } else { |
3778 | log_level = 0; | |
3779 | } | |
1ad2f583 DB |
3780 | |
3781 | env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT); | |
3782 | if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) | |
e07b98d9 | 3783 | env->strict_alignment = true; |
cbd35700 | 3784 | |
0246e64d AS |
3785 | ret = replace_map_fd_with_map_ptr(env); |
3786 | if (ret < 0) | |
3787 | goto skip_full_check; | |
3788 | ||
9bac3d6d | 3789 | env->explored_states = kcalloc(env->prog->len, |
58e2af8b | 3790 | sizeof(struct bpf_verifier_state_list *), |
f1bca824 AS |
3791 | GFP_USER); |
3792 | ret = -ENOMEM; | |
3793 | if (!env->explored_states) | |
3794 | goto skip_full_check; | |
3795 | ||
475fb78f AS |
3796 | ret = check_cfg(env); |
3797 | if (ret < 0) | |
3798 | goto skip_full_check; | |
3799 | ||
1be7f75d AS |
3800 | env->allow_ptr_leaks = capable(CAP_SYS_ADMIN); |
3801 | ||
17a52670 | 3802 | ret = do_check(env); |
cbd35700 | 3803 | |
0246e64d | 3804 | skip_full_check: |
17a52670 | 3805 | while (pop_stack(env, NULL) >= 0); |
f1bca824 | 3806 | free_states(env); |
0246e64d | 3807 | |
9bac3d6d AS |
3808 | if (ret == 0) |
3809 | /* program is valid, convert *(u32*)(ctx + off) accesses */ | |
3810 | ret = convert_ctx_accesses(env); | |
3811 | ||
e245c5c6 | 3812 | if (ret == 0) |
79741b3b | 3813 | ret = fixup_bpf_calls(env); |
e245c5c6 | 3814 | |
cbd35700 AS |
3815 | if (log_level && log_len >= log_size - 1) { |
3816 | BUG_ON(log_len >= log_size); | |
3817 | /* verifier log exceeded user supplied buffer */ | |
3818 | ret = -ENOSPC; | |
3819 | /* fall through to return what was recorded */ | |
3820 | } | |
3821 | ||
3822 | /* copy verifier log back to user space including trailing zero */ | |
3823 | if (log_level && copy_to_user(log_ubuf, log_buf, log_len + 1) != 0) { | |
3824 | ret = -EFAULT; | |
3825 | goto free_log_buf; | |
3826 | } | |
3827 | ||
0246e64d AS |
3828 | if (ret == 0 && env->used_map_cnt) { |
3829 | /* if program passed verifier, update used_maps in bpf_prog_info */ | |
9bac3d6d AS |
3830 | env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt, |
3831 | sizeof(env->used_maps[0]), | |
3832 | GFP_KERNEL); | |
0246e64d | 3833 | |
9bac3d6d | 3834 | if (!env->prog->aux->used_maps) { |
0246e64d AS |
3835 | ret = -ENOMEM; |
3836 | goto free_log_buf; | |
3837 | } | |
3838 | ||
9bac3d6d | 3839 | memcpy(env->prog->aux->used_maps, env->used_maps, |
0246e64d | 3840 | sizeof(env->used_maps[0]) * env->used_map_cnt); |
9bac3d6d | 3841 | env->prog->aux->used_map_cnt = env->used_map_cnt; |
0246e64d AS |
3842 | |
3843 | /* program is valid. Convert pseudo bpf_ld_imm64 into generic | |
3844 | * bpf_ld_imm64 instructions | |
3845 | */ | |
3846 | convert_pseudo_ld_imm64(env); | |
3847 | } | |
cbd35700 AS |
3848 | |
3849 | free_log_buf: | |
3850 | if (log_level) | |
3851 | vfree(log_buf); | |
9bac3d6d | 3852 | if (!env->prog->aux->used_maps) |
0246e64d AS |
3853 | /* if we didn't copy map pointers into bpf_prog_info, release |
3854 | * them now. Otherwise free_bpf_prog_info() will release them. | |
3855 | */ | |
3856 | release_maps(env); | |
9bac3d6d | 3857 | *prog = env->prog; |
3df126f3 | 3858 | err_unlock: |
cbd35700 | 3859 | mutex_unlock(&bpf_verifier_lock); |
3df126f3 JK |
3860 | vfree(env->insn_aux_data); |
3861 | err_free_env: | |
3862 | kfree(env); | |
51580e79 AS |
3863 | return ret; |
3864 | } | |
13a27dfc JK |
3865 | |
3866 | int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops, | |
3867 | void *priv) | |
3868 | { | |
3869 | struct bpf_verifier_env *env; | |
3870 | int ret; | |
3871 | ||
3872 | env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL); | |
3873 | if (!env) | |
3874 | return -ENOMEM; | |
3875 | ||
3876 | env->insn_aux_data = vzalloc(sizeof(struct bpf_insn_aux_data) * | |
3877 | prog->len); | |
3878 | ret = -ENOMEM; | |
3879 | if (!env->insn_aux_data) | |
3880 | goto err_free_env; | |
3881 | env->prog = prog; | |
3882 | env->analyzer_ops = ops; | |
3883 | env->analyzer_priv = priv; | |
3884 | ||
3885 | /* grab the mutex to protect few globals used by verifier */ | |
3886 | mutex_lock(&bpf_verifier_lock); | |
3887 | ||
3888 | log_level = 0; | |
1ad2f583 | 3889 | |
e07b98d9 | 3890 | env->strict_alignment = false; |
1ad2f583 DB |
3891 | if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) |
3892 | env->strict_alignment = true; | |
13a27dfc JK |
3893 | |
3894 | env->explored_states = kcalloc(env->prog->len, | |
3895 | sizeof(struct bpf_verifier_state_list *), | |
3896 | GFP_KERNEL); | |
3897 | ret = -ENOMEM; | |
3898 | if (!env->explored_states) | |
3899 | goto skip_full_check; | |
3900 | ||
3901 | ret = check_cfg(env); | |
3902 | if (ret < 0) | |
3903 | goto skip_full_check; | |
3904 | ||
3905 | env->allow_ptr_leaks = capable(CAP_SYS_ADMIN); | |
3906 | ||
3907 | ret = do_check(env); | |
3908 | ||
3909 | skip_full_check: | |
3910 | while (pop_stack(env, NULL) >= 0); | |
3911 | free_states(env); | |
3912 | ||
3913 | mutex_unlock(&bpf_verifier_lock); | |
3914 | vfree(env->insn_aux_data); | |
3915 | err_free_env: | |
3916 | kfree(env); | |
3917 | return ret; | |
3918 | } | |
3919 | EXPORT_SYMBOL_GPL(bpf_analyzer); |