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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 132struct 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
07016151
DB		 143#define BPF_COMPLEXITY_LIMIT_INSNS 65536
144#define BPF_COMPLEXITY_LIMIT_STACK 1024
145
33ff9823
DB		 146struct bpf_call_arg_meta {
147 struct bpf_map *map_ptr;
435faee1 148 bool raw_mode;
36bbef52 149 bool pkt_access;
435faee1
DB		 150 int regno;
151 int access_size;
33ff9823
DB		 152};
153
cbd35700
AS		 154/* verbose verifier prints what it's seeing
155 * bpf_check() is called under lock, so no race to access these global vars
156 */
157static u32 log_level, log_size, log_len;
158static char *log_buf;
159
160static DEFINE_MUTEX(bpf_verifier_lock);
161
162/* log_level controls verbosity level of eBPF verifier.
163 * verbose() is used to dump the verification trace to the log, so the user
164 * can figure out what's wrong with the program
165 */
1d056d9c 166static __printf(1, 2) void verbose(const char *fmt, ...)
cbd35700
AS		 167{
168 va_list args;
169
170 if (log_level == 0 || log_len >= log_size - 1)
171 return;
172
173 va_start(args, fmt);
174 log_len += vscnprintf(log_buf + log_len, log_size - log_len, fmt, args);
175 va_end(args);
176}
177
17a52670
AS		 178/* string representation of 'enum bpf_reg_type' */
179static const char * const reg_type_str[] = {
180 [NOT_INIT] = "?",
181 [UNKNOWN_VALUE] = "inv",
182 [PTR_TO_CTX] = "ctx",
183 [CONST_PTR_TO_MAP] = "map_ptr",
184 [PTR_TO_MAP_VALUE] = "map_value",
185 [PTR_TO_MAP_VALUE_OR_NULL] = "map_value_or_null",
48461135 186 [PTR_TO_MAP_VALUE_ADJ] = "map_value_adj",
17a52670
AS		 187 [FRAME_PTR] = "fp",
188 [PTR_TO_STACK] = "fp",
189 [CONST_IMM] = "imm",
969bf05e
AS		 190 [PTR_TO_PACKET] = "pkt",
191 [PTR_TO_PACKET_END] = "pkt_end",
17a52670
AS		 192};
193
ebb676da
TG		 194#define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x)
195static const char * const func_id_str[] = {
196 __BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN)
197};
198#undef __BPF_FUNC_STR_FN
199
200static const char *func_id_name(int id)
201{
202 BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID);
203
204 if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id])
205 return func_id_str[id];
206 else
207 return "unknown";
208}
209
58e2af8b 210static void print_verifier_state(struct bpf_verifier_state *state)
17a52670 211{
58e2af8b 212 struct bpf_reg_state *reg;
17a52670
AS		 213 enum bpf_reg_type t;
214 int i;
215
216 for (i = 0; i < MAX_BPF_REG; i++) {
1a0dc1ac
AS		 217 reg = &state->regs[i];
218 t = reg->type;
17a52670
AS		 219 if (t == NOT_INIT)
220 continue;
221 verbose(" R%d=%s", i, reg_type_str[t]);
222 if (t == CONST_IMM || t == PTR_TO_STACK)
969bf05e
AS		 223 verbose("%lld", reg->imm);
224 else if (t == PTR_TO_PACKET)
225 verbose("(id=%d,off=%d,r=%d)",
226 reg->id, reg->off, reg->range);
227 else if (t == UNKNOWN_VALUE && reg->imm)
228 verbose("%lld", reg->imm);
17a52670 229 else if (t == CONST_PTR_TO_MAP || t == PTR_TO_MAP_VALUE ||
48461135
JB		 230 t == PTR_TO_MAP_VALUE_OR_NULL ||
231 t == PTR_TO_MAP_VALUE_ADJ)
57a09bf0 232 verbose("(ks=%d,vs=%d,id=%u)",
1a0dc1ac 233 reg->map_ptr->key_size,
57a09bf0
TG		 234 reg->map_ptr->value_size,
235 reg->id);
48461135 236 if (reg->min_value != BPF_REGISTER_MIN_RANGE)
f23cc643
JB		 237 verbose(",min_value=%lld",
238 (long long)reg->min_value);
48461135
JB		 239 if (reg->max_value != BPF_REGISTER_MAX_RANGE)
240 verbose(",max_value=%llu",
241 (unsigned long long)reg->max_value);
17a52670 242 }
9c399760 243 for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) {
1a0dc1ac 244 if (state->stack_slot_type[i] == STACK_SPILL)
17a52670 245 verbose(" fp%d=%s", -MAX_BPF_STACK + i,
1a0dc1ac 246 reg_type_str[state->spilled_regs[i / BPF_REG_SIZE].type]);
17a52670
AS		 247 }
248 verbose("\n");
249}
250
cbd35700
AS		 251static const char *const bpf_class_string[] = {
252 [BPF_LD] = "ld",
253 [BPF_LDX] = "ldx",
254 [BPF_ST] = "st",
255 [BPF_STX] = "stx",
256 [BPF_ALU] = "alu",
257 [BPF_JMP] = "jmp",
258 [BPF_RET] = "BUG",
259 [BPF_ALU64] = "alu64",
260};
261
687f0715 262static const char *const bpf_alu_string[16] = {
cbd35700
AS		 263 [BPF_ADD >> 4] = "+=",
264 [BPF_SUB >> 4] = "-=",
265 [BPF_MUL >> 4] = "*=",
266 [BPF_DIV >> 4] = "/=",
267 [BPF_OR >> 4] = "|=",
268 [BPF_AND >> 4] = "&=",
269 [BPF_LSH >> 4] = "<<=",
270 [BPF_RSH >> 4] = ">>=",
271 [BPF_NEG >> 4] = "neg",
272 [BPF_MOD >> 4] = "%=",
273 [BPF_XOR >> 4] = "^=",
274 [BPF_MOV >> 4] = "=",
275 [BPF_ARSH >> 4] = "s>>=",
276 [BPF_END >> 4] = "endian",
277};
278
279static const char *const bpf_ldst_string[] = {
280 [BPF_W >> 3] = "u32",
281 [BPF_H >> 3] = "u16",
282 [BPF_B >> 3] = "u8",
283 [BPF_DW >> 3] = "u64",
284};
285
687f0715 286static const char *const bpf_jmp_string[16] = {
cbd35700
AS		 287 [BPF_JA >> 4] = "jmp",
288 [BPF_JEQ >> 4] = "==",
289 [BPF_JGT >> 4] = ">",
290 [BPF_JGE >> 4] = ">=",
291 [BPF_JSET >> 4] = "&",
292 [BPF_JNE >> 4] = "!=",
293 [BPF_JSGT >> 4] = "s>",
294 [BPF_JSGE >> 4] = "s>=",
295 [BPF_CALL >> 4] = "call",
296 [BPF_EXIT >> 4] = "exit",
297};
298
299static void print_bpf_insn(struct bpf_insn *insn)
300{
301 u8 class = BPF_CLASS(insn->code);
302
303 if (class == BPF_ALU || class == BPF_ALU64) {
304 if (BPF_SRC(insn->code) == BPF_X)
305 verbose("(%02x) %sr%d %s %sr%d\n",
306 insn->code, class == BPF_ALU ? "(u32) " : "",
307 insn->dst_reg,
308 bpf_alu_string[BPF_OP(insn->code) >> 4],
309 class == BPF_ALU ? "(u32) " : "",
310 insn->src_reg);
311 else
312 verbose("(%02x) %sr%d %s %s%d\n",
313 insn->code, class == BPF_ALU ? "(u32) " : "",
314 insn->dst_reg,
315 bpf_alu_string[BPF_OP(insn->code) >> 4],
316 class == BPF_ALU ? "(u32) " : "",
317 insn->imm);
318 } else if (class == BPF_STX) {
319 if (BPF_MODE(insn->code) == BPF_MEM)
320 verbose("(%02x) *(%s *)(r%d %+d) = r%d\n",
321 insn->code,
322 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
323 insn->dst_reg,
324 insn->off, insn->src_reg);
325 else if (BPF_MODE(insn->code) == BPF_XADD)
326 verbose("(%02x) lock *(%s *)(r%d %+d) += r%d\n",
327 insn->code,
328 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
329 insn->dst_reg, insn->off,
330 insn->src_reg);
331 else
332 verbose("BUG_%02x\n", insn->code);
333 } else if (class == BPF_ST) {
334 if (BPF_MODE(insn->code) != BPF_MEM) {
335 verbose("BUG_st_%02x\n", insn->code);
336 return;
337 }
338 verbose("(%02x) *(%s *)(r%d %+d) = %d\n",
339 insn->code,
340 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
341 insn->dst_reg,
342 insn->off, insn->imm);
343 } else if (class == BPF_LDX) {
344 if (BPF_MODE(insn->code) != BPF_MEM) {
345 verbose("BUG_ldx_%02x\n", insn->code);
346 return;
347 }
348 verbose("(%02x) r%d = *(%s *)(r%d %+d)\n",
349 insn->code, insn->dst_reg,
350 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
351 insn->src_reg, insn->off);
352 } else if (class == BPF_LD) {
353 if (BPF_MODE(insn->code) == BPF_ABS) {
354 verbose("(%02x) r0 = *(%s *)skb[%d]\n",
355 insn->code,
356 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
357 insn->imm);
358 } else if (BPF_MODE(insn->code) == BPF_IND) {
359 verbose("(%02x) r0 = *(%s *)skb[r%d + %d]\n",
360 insn->code,
361 bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
362 insn->src_reg, insn->imm);
363 } else if (BPF_MODE(insn->code) == BPF_IMM) {
364 verbose("(%02x) r%d = 0x%x\n",
365 insn->code, insn->dst_reg, insn->imm);
366 } else {
367 verbose("BUG_ld_%02x\n", insn->code);
368 return;
369 }
370 } else if (class == BPF_JMP) {
371 u8 opcode = BPF_OP(insn->code);
372
373 if (opcode == BPF_CALL) {
ebb676da
TG		 374 verbose("(%02x) call %s#%d\n", insn->code,
375 func_id_name(insn->imm), insn->imm);
cbd35700
AS		 376 } else if (insn->code == (BPF_JMP | BPF_JA)) {
377 verbose("(%02x) goto pc%+d\n",
378 insn->code, insn->off);
379 } else if (insn->code == (BPF_JMP | BPF_EXIT)) {
380 verbose("(%02x) exit\n", insn->code);
381 } else if (BPF_SRC(insn->code) == BPF_X) {
382 verbose("(%02x) if r%d %s r%d goto pc%+d\n",
383 insn->code, insn->dst_reg,
384 bpf_jmp_string[BPF_OP(insn->code) >> 4],
385 insn->src_reg, insn->off);
386 } else {
387 verbose("(%02x) if r%d %s 0x%x goto pc%+d\n",
388 insn->code, insn->dst_reg,
389 bpf_jmp_string[BPF_OP(insn->code) >> 4],
390 insn->imm, insn->off);
391 }
392 } else {
393 verbose("(%02x) %s\n", insn->code, bpf_class_string[class]);
394 }
395}
396
58e2af8b 397static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx)
17a52670 398{
58e2af8b 399 struct bpf_verifier_stack_elem *elem;
17a52670
AS		 400 int insn_idx;
401
402 if (env->head == NULL)
403 return -1;
404
405 memcpy(&env->cur_state, &env->head->st, sizeof(env->cur_state));
406 insn_idx = env->head->insn_idx;
407 if (prev_insn_idx)
408 *prev_insn_idx = env->head->prev_insn_idx;
409 elem = env->head->next;
410 kfree(env->head);
411 env->head = elem;
412 env->stack_size--;
413 return insn_idx;
414}
415
58e2af8b
JK		 416static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env,
417 int insn_idx, int prev_insn_idx)
17a52670 418{
58e2af8b 419 struct bpf_verifier_stack_elem *elem;
17a52670 420
58e2af8b 421 elem = kmalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL);
17a52670
AS		 422 if (!elem)
423 goto err;
424
425 memcpy(&elem->st, &env->cur_state, sizeof(env->cur_state));
426 elem->insn_idx = insn_idx;
427 elem->prev_insn_idx = prev_insn_idx;
428 elem->next = env->head;
429 env->head = elem;
430 env->stack_size++;
07016151 431 if (env->stack_size > BPF_COMPLEXITY_LIMIT_STACK) {
17a52670
AS		 432 verbose("BPF program is too complex\n");
433 goto err;
434 }
435 return &elem->st;
436err:
437 /* pop all elements and return */
438 while (pop_stack(env, NULL) >= 0);
439 return NULL;
440}
441
442#define CALLER_SAVED_REGS 6
443static const int caller_saved[CALLER_SAVED_REGS] = {
444 BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5
445};
446
58e2af8b 447static void init_reg_state(struct bpf_reg_state *regs)
17a52670
AS		 448{
449 int i;
450
451 for (i = 0; i < MAX_BPF_REG; i++) {
452 regs[i].type = NOT_INIT;
453 regs[i].imm = 0;
48461135
JB		 454 regs[i].min_value = BPF_REGISTER_MIN_RANGE;
455 regs[i].max_value = BPF_REGISTER_MAX_RANGE;
17a52670
AS		 456 }
457
458 /* frame pointer */
459 regs[BPF_REG_FP].type = FRAME_PTR;
460
461 /* 1st arg to a function */
462 regs[BPF_REG_1].type = PTR_TO_CTX;
463}
464
6760bf2d 465static void __mark_reg_unknown_value(struct bpf_reg_state *regs, u32 regno)
17a52670 466{
17a52670 467 regs[regno].type = UNKNOWN_VALUE;
57a09bf0 468 regs[regno].id = 0;
17a52670 469 regs[regno].imm = 0;
17a52670
AS		 470}
471
6760bf2d
DB		 472static void mark_reg_unknown_value(struct bpf_reg_state *regs, u32 regno)
473{
474 BUG_ON(regno >= MAX_BPF_REG);
475 __mark_reg_unknown_value(regs, regno);
476}
477
48461135
JB		 478static void reset_reg_range_values(struct bpf_reg_state *regs, u32 regno)
479{
480 regs[regno].min_value = BPF_REGISTER_MIN_RANGE;
481 regs[regno].max_value = BPF_REGISTER_MAX_RANGE;
482}
483
f0318d01
GB		 484static void mark_reg_unknown_value_and_range(struct bpf_reg_state *regs,
485 u32 regno)
486{
487 mark_reg_unknown_value(regs, regno);
488 reset_reg_range_values(regs, regno);
489}
490
17a52670
AS		 491enum reg_arg_type {
492 SRC_OP, /* register is used as source operand */
493 DST_OP, /* register is used as destination operand */
494 DST_OP_NO_MARK /* same as above, check only, don't mark */
495};
496
58e2af8b 497static int check_reg_arg(struct bpf_reg_state *regs, u32 regno,
17a52670
AS		 498 enum reg_arg_type t)
499{
500 if (regno >= MAX_BPF_REG) {
501 verbose("R%d is invalid\n", regno);
502 return -EINVAL;
503 }
504
505 if (t == SRC_OP) {
506 /* check whether register used as source operand can be read */
507 if (regs[regno].type == NOT_INIT) {
508 verbose("R%d !read_ok\n", regno);
509 return -EACCES;
510 }
511 } else {
512 /* check whether register used as dest operand can be written to */
513 if (regno == BPF_REG_FP) {
514 verbose("frame pointer is read only\n");
515 return -EACCES;
516 }
517 if (t == DST_OP)
518 mark_reg_unknown_value(regs, regno);
519 }
520 return 0;
521}
522
523static int bpf_size_to_bytes(int bpf_size)
524{
525 if (bpf_size == BPF_W)
526 return 4;
527 else if (bpf_size == BPF_H)
528 return 2;
529 else if (bpf_size == BPF_B)
530 return 1;
531 else if (bpf_size == BPF_DW)
532 return 8;
533 else
534 return -EINVAL;
535}
536
1be7f75d
AS		 537static bool is_spillable_regtype(enum bpf_reg_type type)
538{
539 switch (type) {
540 case PTR_TO_MAP_VALUE:
541 case PTR_TO_MAP_VALUE_OR_NULL:
f0318d01 542 case PTR_TO_MAP_VALUE_ADJ:
1be7f75d
AS		 543 case PTR_TO_STACK:
544 case PTR_TO_CTX:
969bf05e
AS		 545 case PTR_TO_PACKET:
546 case PTR_TO_PACKET_END:
1be7f75d
AS		 547 case FRAME_PTR:
548 case CONST_PTR_TO_MAP:
549 return true;
550 default:
551 return false;
552 }
553}
554
17a52670
AS		 555/* check_stack_read/write functions track spill/fill of registers,
556 * stack boundary and alignment are checked in check_mem_access()
557 */
58e2af8b
JK		 558static int check_stack_write(struct bpf_verifier_state *state, int off,
559 int size, int value_regno)
17a52670 560{
17a52670 561 int i;
9c399760
AS		 562 /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
563 * so it's aligned access and [off, off + size) are within stack limits
564 */
17a52670
AS		 565
566 if (value_regno >= 0 &&
1be7f75d 567 is_spillable_regtype(state->regs[value_regno].type)) {
17a52670
AS		 568
569 /* register containing pointer is being spilled into stack */
9c399760 570 if (size != BPF_REG_SIZE) {
17a52670
AS		 571 verbose("invalid size of register spill\n");
572 return -EACCES;
573 }
574
17a52670 575 /* save register state */
9c399760
AS		 576 state->spilled_regs[(MAX_BPF_STACK + off) / BPF_REG_SIZE] =
577 state->regs[value_regno];
17a52670 578
9c399760
AS		 579 for (i = 0; i < BPF_REG_SIZE; i++)
580 state->stack_slot_type[MAX_BPF_STACK + off + i] = STACK_SPILL;
581 } else {
17a52670 582 /* regular write of data into stack */
9c399760 583 state->spilled_regs[(MAX_BPF_STACK + off) / BPF_REG_SIZE] =
58e2af8b 584 (struct bpf_reg_state) {};
9c399760
AS		 585
586 for (i = 0; i < size; i++)
587 state->stack_slot_type[MAX_BPF_STACK + off + i] = STACK_MISC;
17a52670
AS		 588 }
589 return 0;
590}
591
58e2af8b 592static int check_stack_read(struct bpf_verifier_state *state, int off, int size,
17a52670
AS		 593 int value_regno)
594{
9c399760 595 u8 *slot_type;
17a52670 596 int i;
17a52670 597
9c399760 598 slot_type = &state->stack_slot_type[MAX_BPF_STACK + off];
17a52670 599
9c399760
AS		 600 if (slot_type[0] == STACK_SPILL) {
601 if (size != BPF_REG_SIZE) {
17a52670
AS		 602 verbose("invalid size of register spill\n");
603 return -EACCES;
604 }
9c399760
AS		 605 for (i = 1; i < BPF_REG_SIZE; i++) {
606 if (slot_type[i] != STACK_SPILL) {
17a52670
AS		 607 verbose("corrupted spill memory\n");
608 return -EACCES;
609 }
610 }
611
612 if (value_regno >= 0)
613 /* restore register state from stack */
9c399760
AS		 614 state->regs[value_regno] =
615 state->spilled_regs[(MAX_BPF_STACK + off) / BPF_REG_SIZE];
17a52670
AS		 616 return 0;
617 } else {
618 for (i = 0; i < size; i++) {
9c399760 619 if (slot_type[i] != STACK_MISC) {
17a52670
AS		 620 verbose("invalid read from stack off %d+%d size %d\n",
621 off, i, size);
622 return -EACCES;
623 }
624 }
625 if (value_regno >= 0)
626 /* have read misc data from the stack */
f0318d01
GB		 627 mark_reg_unknown_value_and_range(state->regs,
628 value_regno);
17a52670
AS		 629 return 0;
630 }
631}
632
633/* check read/write into map element returned by bpf_map_lookup_elem() */
58e2af8b 634static int check_map_access(struct bpf_verifier_env *env, u32 regno, int off,
17a52670
AS		 635 int size)
636{
637 struct bpf_map *map = env->cur_state.regs[regno].map_ptr;
638
5722569b 639 if (off < 0 || size <= 0 || off + size > map->value_size) {
17a52670
AS		 640 verbose("invalid access to map value, value_size=%d off=%d size=%d\n",
641 map->value_size, off, size);
642 return -EACCES;
643 }
644 return 0;
645}
646
dbcfe5f7
GB		 647/* check read/write into an adjusted map element */
648static int check_map_access_adj(struct bpf_verifier_env *env, u32 regno,
649 int off, int size)
650{
651 struct bpf_verifier_state *state = &env->cur_state;
652 struct bpf_reg_state *reg = &state->regs[regno];
653 int err;
654
655 /* We adjusted the register to this map value, so we
656 * need to change off and size to min_value and max_value
657 * respectively to make sure our theoretical access will be
658 * safe.
659 */
660 if (log_level)
661 print_verifier_state(state);
662 env->varlen_map_value_access = true;
663 /* The minimum value is only important with signed
664 * comparisons where we can't assume the floor of a
665 * value is 0. If we are using signed variables for our
666 * index'es we need to make sure that whatever we use
667 * will have a set floor within our range.
668 */
669 if (reg->min_value < 0) {
670 verbose("R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
671 regno);
672 return -EACCES;
673 }
674 err = check_map_access(env, regno, reg->min_value + off, size);
675 if (err) {
676 verbose("R%d min value is outside of the array range\n",
677 regno);
678 return err;
679 }
680
681 /* If we haven't set a max value then we need to bail
682 * since we can't be sure we won't do bad things.
683 */
684 if (reg->max_value == BPF_REGISTER_MAX_RANGE) {
685 verbose("R%d unbounded memory access, make sure to bounds check any array access into a map\n",
686 regno);
687 return -EACCES;
688 }
689 return check_map_access(env, regno, reg->max_value + off, size);
690}
691
969bf05e
AS		 692#define MAX_PACKET_OFF 0xffff
693
58e2af8b 694static bool may_access_direct_pkt_data(struct bpf_verifier_env *env,
3a0af8fd
TG		 695 const struct bpf_call_arg_meta *meta,
696 enum bpf_access_type t)
4acf6c0b 697{
36bbef52 698 switch (env->prog->type) {
3a0af8fd
TG		 699 case BPF_PROG_TYPE_LWT_IN:
700 case BPF_PROG_TYPE_LWT_OUT:
701 /* dst_input() and dst_output() can't write for now */
702 if (t == BPF_WRITE)
703 return false;
7e57fbb2 704 /* fallthrough */
36bbef52
DB		 705 case BPF_PROG_TYPE_SCHED_CLS:
706 case BPF_PROG_TYPE_SCHED_ACT:
4acf6c0b 707 case BPF_PROG_TYPE_XDP:
3a0af8fd 708 case BPF_PROG_TYPE_LWT_XMIT:
36bbef52
DB		 709 if (meta)
710 return meta->pkt_access;
711
712 env->seen_direct_write = true;
4acf6c0b
BB		 713 return true;
714 default:
715 return false;
716 }
717}
718
58e2af8b 719static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
969bf05e
AS		 720 int size)
721{
58e2af8b
JK		 722 struct bpf_reg_state *regs = env->cur_state.regs;
723 struct bpf_reg_state *reg = &regs[regno];
969bf05e 724
d91b28ed 725 off += reg->off;
b399cf64 726 if (off < 0 || size <= 0 || off + size > reg->range) {
d91b28ed
AS		 727 verbose("invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
728 off, size, regno, reg->id, reg->off, reg->range);
969bf05e
AS		 729 return -EACCES;
730 }
731 return 0;
732}
733
17a52670 734/* check access to 'struct bpf_context' fields */
58e2af8b 735static int check_ctx_access(struct bpf_verifier_env *env, int off, int size,
19de99f7 736 enum bpf_access_type t, enum bpf_reg_type *reg_type)
17a52670 737{
13a27dfc
JK		 738 /* for analyzer ctx accesses are already validated and converted */
739 if (env->analyzer_ops)
740 return 0;
741
17a52670 742 if (env->prog->aux->ops->is_valid_access &&
19de99f7 743 env->prog->aux->ops->is_valid_access(off, size, t, reg_type)) {
32bbe007
AS		 744 /* remember the offset of last byte accessed in ctx */
745 if (env->prog->aux->max_ctx_offset < off + size)
746 env->prog->aux->max_ctx_offset = off + size;
17a52670 747 return 0;
32bbe007 748 }
17a52670
AS		 749
750 verbose("invalid bpf_context access off=%d size=%d\n", off, size);
751 return -EACCES;
752}
753
58e2af8b 754static bool is_pointer_value(struct bpf_verifier_env *env, int regno)
1be7f75d
AS		 755{
756 if (env->allow_ptr_leaks)
757 return false;
758
759 switch (env->cur_state.regs[regno].type) {
760 case UNKNOWN_VALUE:
761 case CONST_IMM:
762 return false;
763 default:
764 return true;
765 }
766}
767
58e2af8b
JK		 768static int check_ptr_alignment(struct bpf_verifier_env *env,
769 struct bpf_reg_state *reg, int off, int size)
969bf05e 770{
48461135 771 if (reg->type != PTR_TO_PACKET && reg->type != PTR_TO_MAP_VALUE_ADJ) {
969bf05e 772 if (off % size != 0) {
58e2af8b
JK		 773 verbose("misaligned access off %d size %d\n",
774 off, size);
969bf05e
AS		 775 return -EACCES;
776 } else {
777 return 0;
778 }
779 }
780
969bf05e
AS		 781 if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
782 /* misaligned access to packet is ok on x86,arm,arm64 */
783 return 0;
784
785 if (reg->id && size != 1) {
786 verbose("Unknown packet alignment. Only byte-sized access allowed\n");
787 return -EACCES;
788 }
789
790 /* skb->data is NET_IP_ALIGN-ed */
48461135
JB		 791 if (reg->type == PTR_TO_PACKET &&
792 (NET_IP_ALIGN + reg->off + off) % size != 0) {
969bf05e
AS		 793 verbose("misaligned packet access off %d+%d+%d size %d\n",
794 NET_IP_ALIGN, reg->off, off, size);
795 return -EACCES;
796 }
797 return 0;
798}
799
17a52670
AS		 800/* check whether memory at (regno + off) is accessible for t = (read | write)
801 * if t==write, value_regno is a register which value is stored into memory
802 * if t==read, value_regno is a register which will receive the value from memory
803 * if t==write && value_regno==-1, some unknown value is stored into memory
804 * if t==read && value_regno==-1, don't care what we read from memory
805 */
58e2af8b 806static int check_mem_access(struct bpf_verifier_env *env, u32 regno, int off,
17a52670
AS		 807 int bpf_size, enum bpf_access_type t,
808 int value_regno)
809{
58e2af8b
JK		 810 struct bpf_verifier_state *state = &env->cur_state;
811 struct bpf_reg_state *reg = &state->regs[regno];
17a52670
AS		 812 int size, err = 0;
813
1a0dc1ac
AS		 814 if (reg->type == PTR_TO_STACK)
815 off += reg->imm;
24b4d2ab 816
17a52670
AS		 817 size = bpf_size_to_bytes(bpf_size);
818 if (size < 0)
819 return size;
820
969bf05e
AS		 821 err = check_ptr_alignment(env, reg, off, size);
822 if (err)
823 return err;
17a52670 824
48461135
JB		 825 if (reg->type == PTR_TO_MAP_VALUE ||
826 reg->type == PTR_TO_MAP_VALUE_ADJ) {
1be7f75d
AS		 827 if (t == BPF_WRITE && value_regno >= 0 &&
828 is_pointer_value(env, value_regno)) {
829 verbose("R%d leaks addr into map\n", value_regno);
830 return -EACCES;
831 }
48461135 832
dbcfe5f7
GB		 833 if (reg->type == PTR_TO_MAP_VALUE_ADJ)
834 err = check_map_access_adj(env, regno, off, size);
835 else
836 err = check_map_access(env, regno, off, size);
17a52670 837 if (!err && t == BPF_READ && value_regno >= 0)
f0318d01
GB		 838 mark_reg_unknown_value_and_range(state->regs,
839 value_regno);
17a52670 840
1a0dc1ac 841 } else if (reg->type == PTR_TO_CTX) {
19de99f7
AS		 842 enum bpf_reg_type reg_type = UNKNOWN_VALUE;
843
1be7f75d
AS		 844 if (t == BPF_WRITE && value_regno >= 0 &&
845 is_pointer_value(env, value_regno)) {
846 verbose("R%d leaks addr into ctx\n", value_regno);
847 return -EACCES;
848 }
19de99f7 849 err = check_ctx_access(env, off, size, t, &reg_type);
969bf05e 850 if (!err && t == BPF_READ && value_regno >= 0) {
f0318d01
GB		 851 mark_reg_unknown_value_and_range(state->regs,
852 value_regno);
1955351d
MS		 853 /* note that reg.[id|off|range] == 0 */
854 state->regs[value_regno].type = reg_type;
969bf05e 855 }
17a52670 856
1a0dc1ac 857 } else if (reg->type == FRAME_PTR || reg->type == PTR_TO_STACK) {
17a52670
AS		 858 if (off >= 0 || off < -MAX_BPF_STACK) {
859 verbose("invalid stack off=%d size=%d\n", off, size);
860 return -EACCES;
861 }
1be7f75d
AS		 862 if (t == BPF_WRITE) {
863 if (!env->allow_ptr_leaks &&
864 state->stack_slot_type[MAX_BPF_STACK + off] == STACK_SPILL &&
865 size != BPF_REG_SIZE) {
866 verbose("attempt to corrupt spilled pointer on stack\n");
867 return -EACCES;
868 }
17a52670 869 err = check_stack_write(state, off, size, value_regno);
1be7f75d 870 } else {
17a52670 871 err = check_stack_read(state, off, size, value_regno);
1be7f75d 872 }
969bf05e 873 } else if (state->regs[regno].type == PTR_TO_PACKET) {
3a0af8fd 874 if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) {
969bf05e
AS		 875 verbose("cannot write into packet\n");
876 return -EACCES;
877 }
4acf6c0b
BB		 878 if (t == BPF_WRITE && value_regno >= 0 &&
879 is_pointer_value(env, value_regno)) {
880 verbose("R%d leaks addr into packet\n", value_regno);
881 return -EACCES;
882 }
969bf05e
AS		 883 err = check_packet_access(env, regno, off, size);
884 if (!err && t == BPF_READ && value_regno >= 0)
f0318d01
GB		 885 mark_reg_unknown_value_and_range(state->regs,
886 value_regno);
17a52670
AS		 887 } else {
888 verbose("R%d invalid mem access '%s'\n",
1a0dc1ac 889 regno, reg_type_str[reg->type]);
17a52670
AS		 890 return -EACCES;
891 }
969bf05e
AS		 892
893 if (!err && size <= 2 && value_regno >= 0 && env->allow_ptr_leaks &&
894 state->regs[value_regno].type == UNKNOWN_VALUE) {
895 /* 1 or 2 byte load zero-extends, determine the number of
896 * zero upper bits. Not doing it fo 4 byte load, since
897 * such values cannot be added to ptr_to_packet anyway.
898 */
899 state->regs[value_regno].imm = 64 - size * 8;
900 }
17a52670
AS		 901 return err;
902}
903
58e2af8b 904static int check_xadd(struct bpf_verifier_env *env, struct bpf_insn *insn)
17a52670 905{
58e2af8b 906 struct bpf_reg_state *regs = env->cur_state.regs;
17a52670
AS		 907 int err;
908
909 if ((BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) ||
910 insn->imm != 0) {
911 verbose("BPF_XADD uses reserved fields\n");
912 return -EINVAL;
913 }
914
915 /* check src1 operand */
916 err = check_reg_arg(regs, insn->src_reg, SRC_OP);
917 if (err)
918 return err;
919
920 /* check src2 operand */
921 err = check_reg_arg(regs, insn->dst_reg, SRC_OP);
922 if (err)
923 return err;
924
925 /* check whether atomic_add can read the memory */
926 err = check_mem_access(env, insn->dst_reg, insn->off,
927 BPF_SIZE(insn->code), BPF_READ, -1);
928 if (err)
929 return err;
930
931 /* check whether atomic_add can write into the same memory */
932 return check_mem_access(env, insn->dst_reg, insn->off,
933 BPF_SIZE(insn->code), BPF_WRITE, -1);
934}
935
936/* when register 'regno' is passed into function that will read 'access_size'
937 * bytes from that pointer, make sure that it's within stack boundary
938 * and all elements of stack are initialized
939 */
58e2af8b 940static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
435faee1
DB		 941 int access_size, bool zero_size_allowed,
942 struct bpf_call_arg_meta *meta)
17a52670 943{
58e2af8b
JK		 944 struct bpf_verifier_state *state = &env->cur_state;
945 struct bpf_reg_state *regs = state->regs;
17a52670
AS		 946 int off, i;
947
8e2fe1d9
DB		 948 if (regs[regno].type != PTR_TO_STACK) {
949 if (zero_size_allowed && access_size == 0 &&
950 regs[regno].type == CONST_IMM &&
951 regs[regno].imm == 0)
952 return 0;
953
954 verbose("R%d type=%s expected=%s\n", regno,
955 reg_type_str[regs[regno].type],
956 reg_type_str[PTR_TO_STACK]);
17a52670 957 return -EACCES;
8e2fe1d9 958 }
17a52670
AS		 959
960 off = regs[regno].imm;
961 if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 ||
962 access_size <= 0) {
963 verbose("invalid stack type R%d off=%d access_size=%d\n",
964 regno, off, access_size);
965 return -EACCES;
966 }
967
435faee1
DB		 968 if (meta && meta->raw_mode) {
969 meta->access_size = access_size;
970 meta->regno = regno;
971 return 0;
972 }
973
17a52670 974 for (i = 0; i < access_size; i++) {
9c399760 975 if (state->stack_slot_type[MAX_BPF_STACK + off + i] != STACK_MISC) {
17a52670
AS		 976 verbose("invalid indirect read from stack off %d+%d size %d\n",
977 off, i, access_size);
978 return -EACCES;
979 }
980 }
981 return 0;
982}
983
06c1c049
GB		 984static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
985 int access_size, bool zero_size_allowed,
986 struct bpf_call_arg_meta *meta)
987{
988 struct bpf_reg_state *regs = env->cur_state.regs;
989
990 switch (regs[regno].type) {
991 case PTR_TO_PACKET:
992 return check_packet_access(env, regno, 0, access_size);
993 case PTR_TO_MAP_VALUE:
994 return check_map_access(env, regno, 0, access_size);
995 case PTR_TO_MAP_VALUE_ADJ:
996 return check_map_access_adj(env, regno, 0, access_size);
997 default: /* const_imm|ptr_to_stack or invalid ptr */
998 return check_stack_boundary(env, regno, access_size,
999 zero_size_allowed, meta);
1000 }
1001}
1002
58e2af8b 1003static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
33ff9823
DB		 1004 enum bpf_arg_type arg_type,
1005 struct bpf_call_arg_meta *meta)
17a52670 1006{
58e2af8b 1007 struct bpf_reg_state *regs = env->cur_state.regs, *reg = &regs[regno];
6841de8b 1008 enum bpf_reg_type expected_type, type = reg->type;
17a52670
AS		 1009 int err = 0;
1010
80f1d68c 1011 if (arg_type == ARG_DONTCARE)
17a52670
AS		 1012 return 0;
1013
6841de8b 1014 if (type == NOT_INIT) {
17a52670
AS		 1015 verbose("R%d !read_ok\n", regno);
1016 return -EACCES;
1017 }
1018
1be7f75d
AS		 1019 if (arg_type == ARG_ANYTHING) {
1020 if (is_pointer_value(env, regno)) {
1021 verbose("R%d leaks addr into helper function\n", regno);
1022 return -EACCES;
1023 }
80f1d68c 1024 return 0;
1be7f75d 1025 }
80f1d68c 1026
3a0af8fd
TG		 1027 if (type == PTR_TO_PACKET &&
1028 !may_access_direct_pkt_data(env, meta, BPF_READ)) {
36bbef52 1029 verbose("helper access to the packet is not allowed\n");
6841de8b
AS		 1030 return -EACCES;
1031 }
1032
8e2fe1d9 1033 if (arg_type == ARG_PTR_TO_MAP_KEY ||
17a52670
AS		 1034 arg_type == ARG_PTR_TO_MAP_VALUE) {
1035 expected_type = PTR_TO_STACK;
6841de8b
AS		 1036 if (type != PTR_TO_PACKET && type != expected_type)
1037 goto err_type;
39f19ebb
AS		 1038 } else if (arg_type == ARG_CONST_SIZE ||
1039 arg_type == ARG_CONST_SIZE_OR_ZERO) {
17a52670 1040 expected_type = CONST_IMM;
06c1c049
GB		 1041 /* One exception. Allow UNKNOWN_VALUE registers when the
1042 * boundaries are known and don't cause unsafe memory accesses
1043 */
1044 if (type != UNKNOWN_VALUE && type != expected_type)
6841de8b 1045 goto err_type;
17a52670
AS		 1046 } else if (arg_type == ARG_CONST_MAP_PTR) {
1047 expected_type = CONST_PTR_TO_MAP;
6841de8b
AS		 1048 if (type != expected_type)
1049 goto err_type;
608cd71a
AS		 1050 } else if (arg_type == ARG_PTR_TO_CTX) {
1051 expected_type = PTR_TO_CTX;
6841de8b
AS		 1052 if (type != expected_type)
1053 goto err_type;
39f19ebb
AS		 1054 } else if (arg_type == ARG_PTR_TO_MEM ||
1055 arg_type == ARG_PTR_TO_UNINIT_MEM) {
8e2fe1d9
DB		 1056 expected_type = PTR_TO_STACK;
1057 /* One exception here. In case function allows for NULL to be
1058 * passed in as argument, it's a CONST_IMM type. Final test
1059 * happens during stack boundary checking.
1060 */
6841de8b
AS		 1061 if (type == CONST_IMM && reg->imm == 0)
1062 /* final test in check_stack_boundary() */;
5722569b
GB		 1063 else if (type != PTR_TO_PACKET && type != PTR_TO_MAP_VALUE &&
1064 type != PTR_TO_MAP_VALUE_ADJ && type != expected_type)
6841de8b 1065 goto err_type;
39f19ebb 1066 meta->raw_mode = arg_type == ARG_PTR_TO_UNINIT_MEM;
17a52670
AS		 1067 } else {
1068 verbose("unsupported arg_type %d\n", arg_type);
1069 return -EFAULT;
1070 }
1071
17a52670
AS		 1072 if (arg_type == ARG_CONST_MAP_PTR) {
1073 /* bpf_map_xxx(map_ptr) call: remember that map_ptr */
33ff9823 1074 meta->map_ptr = reg->map_ptr;
17a52670
AS		 1075 } else if (arg_type == ARG_PTR_TO_MAP_KEY) {
1076 /* bpf_map_xxx(..., map_ptr, ..., key) call:
1077 * check that [key, key + map->key_size) are within
1078 * stack limits and initialized
1079 */
33ff9823 1080 if (!meta->map_ptr) {
17a52670
AS		 1081 /* in function declaration map_ptr must come before
1082 * map_key, so that it's verified and known before
1083 * we have to check map_key here. Otherwise it means
1084 * that kernel subsystem misconfigured verifier
1085 */
1086 verbose("invalid map_ptr to access map->key\n");
1087 return -EACCES;
1088 }
6841de8b
AS		 1089 if (type == PTR_TO_PACKET)
1090 err = check_packet_access(env, regno, 0,
1091 meta->map_ptr->key_size);
1092 else
1093 err = check_stack_boundary(env, regno,
1094 meta->map_ptr->key_size,
1095 false, NULL);
17a52670
AS		 1096 } else if (arg_type == ARG_PTR_TO_MAP_VALUE) {
1097 /* bpf_map_xxx(..., map_ptr, ..., value) call:
1098 * check [value, value + map->value_size) validity
1099 */
33ff9823 1100 if (!meta->map_ptr) {
17a52670
AS		 1101 /* kernel subsystem misconfigured verifier */
1102 verbose("invalid map_ptr to access map->value\n");
1103 return -EACCES;
1104 }
6841de8b
AS		 1105 if (type == PTR_TO_PACKET)
1106 err = check_packet_access(env, regno, 0,
1107 meta->map_ptr->value_size);
1108 else
1109 err = check_stack_boundary(env, regno,
1110 meta->map_ptr->value_size,
1111 false, NULL);
39f19ebb
AS		 1112 } else if (arg_type == ARG_CONST_SIZE ||
1113 arg_type == ARG_CONST_SIZE_OR_ZERO) {
1114 bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO);
17a52670 1115
17a52670
AS		 1116 /* bpf_xxx(..., buf, len) call will access 'len' bytes
1117 * from stack pointer 'buf'. Check it
1118 * note: regno == len, regno - 1 == buf
1119 */
1120 if (regno == 0) {
1121 /* kernel subsystem misconfigured verifier */
39f19ebb 1122 verbose("ARG_CONST_SIZE cannot be first argument\n");
17a52670
AS		 1123 return -EACCES;
1124 }
06c1c049
GB		 1125
1126 /* If the register is UNKNOWN_VALUE, the access check happens
1127 * using its boundaries. Otherwise, just use its imm
1128 */
1129 if (type == UNKNOWN_VALUE) {
1130 /* For unprivileged variable accesses, disable raw
1131 * mode so that the program is required to
1132 * initialize all the memory that the helper could
1133 * just partially fill up.
1134 */
1135 meta = NULL;
1136
1137 if (reg->min_value < 0) {
1138 verbose("R%d min value is negative, either use unsigned or 'var &= const'\n",
1139 regno);
1140 return -EACCES;
1141 }
1142
1143 if (reg->min_value == 0) {
1144 err = check_helper_mem_access(env, regno - 1, 0,
1145 zero_size_allowed,
1146 meta);
1147 if (err)
1148 return err;
1149 }
1150
1151 if (reg->max_value == BPF_REGISTER_MAX_RANGE) {
1152 verbose("R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n",
1153 regno);
1154 return -EACCES;
1155 }
1156 err = check_helper_mem_access(env, regno - 1,
1157 reg->max_value,
1158 zero_size_allowed, meta);
1159 if (err)
1160 return err;
1161 } else {
1162 /* register is CONST_IMM */
1163 err = check_helper_mem_access(env, regno - 1, reg->imm,
1164 zero_size_allowed, meta);
1165 }
17a52670
AS		 1166 }
1167
1168 return err;
6841de8b
AS		 1169err_type:
1170 verbose("R%d type=%s expected=%s\n", regno,
1171 reg_type_str[type], reg_type_str[expected_type]);
1172 return -EACCES;
17a52670
AS		 1173}
1174
35578d79
KX		 1175static int check_map_func_compatibility(struct bpf_map *map, int func_id)
1176{
35578d79
KX		 1177 if (!map)
1178 return 0;
1179
6aff67c8
AS		 1180 /* We need a two way check, first is from map perspective ... */
1181 switch (map->map_type) {
1182 case BPF_MAP_TYPE_PROG_ARRAY:
1183 if (func_id != BPF_FUNC_tail_call)
1184 goto error;
1185 break;
1186 case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
1187 if (func_id != BPF_FUNC_perf_event_read &&
1188 func_id != BPF_FUNC_perf_event_output)
1189 goto error;
1190 break;
1191 case BPF_MAP_TYPE_STACK_TRACE:
1192 if (func_id != BPF_FUNC_get_stackid)
1193 goto error;
1194 break;
4ed8ec52 1195 case BPF_MAP_TYPE_CGROUP_ARRAY:
60747ef4 1196 if (func_id != BPF_FUNC_skb_under_cgroup &&
60d20f91 1197 func_id != BPF_FUNC_current_task_under_cgroup)
4a482f34
MKL		 1198 goto error;
1199 break;
6aff67c8
AS		 1200 default:
1201 break;
1202 }
1203
1204 /* ... and second from the function itself. */
1205 switch (func_id) {
1206 case BPF_FUNC_tail_call:
1207 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
1208 goto error;
1209 break;
1210 case BPF_FUNC_perf_event_read:
1211 case BPF_FUNC_perf_event_output:
1212 if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
1213 goto error;
1214 break;
1215 case BPF_FUNC_get_stackid:
1216 if (map->map_type != BPF_MAP_TYPE_STACK_TRACE)
1217 goto error;
1218 break;
60d20f91 1219 case BPF_FUNC_current_task_under_cgroup:
747ea55e 1220 case BPF_FUNC_skb_under_cgroup:
4a482f34
MKL		 1221 if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY)
1222 goto error;
1223 break;
6aff67c8
AS		 1224 default:
1225 break;
35578d79
KX		 1226 }
1227
1228 return 0;
6aff67c8 1229error:
ebb676da
TG		 1230 verbose("cannot pass map_type %d into func %s#%d\n",
1231 map->map_type, func_id_name(func_id), func_id);
6aff67c8 1232 return -EINVAL;
35578d79
KX		 1233}
1234
435faee1
DB		 1235static int check_raw_mode(const struct bpf_func_proto *fn)
1236{
1237 int count = 0;
1238
39f19ebb 1239 if (fn->arg1_type == ARG_PTR_TO_UNINIT_MEM)
435faee1 1240 count++;
39f19ebb 1241 if (fn->arg2_type == ARG_PTR_TO_UNINIT_MEM)
435faee1 1242 count++;
39f19ebb 1243 if (fn->arg3_type == ARG_PTR_TO_UNINIT_MEM)
435faee1 1244 count++;
39f19ebb 1245 if (fn->arg4_type == ARG_PTR_TO_UNINIT_MEM)
435faee1 1246 count++;
39f19ebb 1247 if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM)
435faee1
DB		 1248 count++;
1249
1250 return count > 1 ? -EINVAL : 0;
1251}
1252
58e2af8b 1253static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
969bf05e 1254{
58e2af8b
JK		 1255 struct bpf_verifier_state *state = &env->cur_state;
1256 struct bpf_reg_state *regs = state->regs, *reg;
969bf05e
AS		 1257 int i;
1258
1259 for (i = 0; i < MAX_BPF_REG; i++)
1260 if (regs[i].type == PTR_TO_PACKET ||
1261 regs[i].type == PTR_TO_PACKET_END)
1262 mark_reg_unknown_value(regs, i);
1263
1264 for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) {
1265 if (state->stack_slot_type[i] != STACK_SPILL)
1266 continue;
1267 reg = &state->spilled_regs[i / BPF_REG_SIZE];
1268 if (reg->type != PTR_TO_PACKET &&
1269 reg->type != PTR_TO_PACKET_END)
1270 continue;
1271 reg->type = UNKNOWN_VALUE;
1272 reg->imm = 0;
1273 }
1274}
1275
58e2af8b 1276static int check_call(struct bpf_verifier_env *env, int func_id)
17a52670 1277{
58e2af8b 1278 struct bpf_verifier_state *state = &env->cur_state;
17a52670 1279 const struct bpf_func_proto *fn = NULL;
58e2af8b
JK		 1280 struct bpf_reg_state *regs = state->regs;
1281 struct bpf_reg_state *reg;
33ff9823 1282 struct bpf_call_arg_meta meta;
969bf05e 1283 bool changes_data;
17a52670
AS		 1284 int i, err;
1285
1286 /* find function prototype */
1287 if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) {
ebb676da 1288 verbose("invalid func %s#%d\n", func_id_name(func_id), func_id);
17a52670
AS		 1289 return -EINVAL;
1290 }
1291
1292 if (env->prog->aux->ops->get_func_proto)
1293 fn = env->prog->aux->ops->get_func_proto(func_id);
1294
1295 if (!fn) {
ebb676da 1296 verbose("unknown func %s#%d\n", func_id_name(func_id), func_id);
17a52670
AS		 1297 return -EINVAL;
1298 }
1299
1300 /* eBPF programs must be GPL compatible to use GPL-ed functions */
24701ece 1301 if (!env->prog->gpl_compatible && fn->gpl_only) {
17a52670
AS		 1302 verbose("cannot call GPL only function from proprietary program\n");
1303 return -EINVAL;
1304 }
1305
17bedab2 1306 changes_data = bpf_helper_changes_pkt_data(fn->func);
969bf05e 1307
33ff9823 1308 memset(&meta, 0, sizeof(meta));
36bbef52 1309 meta.pkt_access = fn->pkt_access;
33ff9823 1310
435faee1
DB		 1311 /* We only support one arg being in raw mode at the moment, which
1312 * is sufficient for the helper functions we have right now.
1313 */
1314 err = check_raw_mode(fn);
1315 if (err) {
ebb676da
TG		 1316 verbose("kernel subsystem misconfigured func %s#%d\n",
1317 func_id_name(func_id), func_id);
435faee1
DB		 1318 return err;
1319 }
1320
17a52670 1321 /* check args */
33ff9823 1322 err = check_func_arg(env, BPF_REG_1, fn->arg1_type, &meta);
17a52670
AS		 1323 if (err)
1324 return err;
33ff9823 1325 err = check_func_arg(env, BPF_REG_2, fn->arg2_type, &meta);
17a52670
AS		 1326 if (err)
1327 return err;
33ff9823 1328 err = check_func_arg(env, BPF_REG_3, fn->arg3_type, &meta);
17a52670
AS		 1329 if (err)
1330 return err;
33ff9823 1331 err = check_func_arg(env, BPF_REG_4, fn->arg4_type, &meta);
17a52670
AS		 1332 if (err)
1333 return err;
33ff9823 1334 err = check_func_arg(env, BPF_REG_5, fn->arg5_type, &meta);
17a52670
AS		 1335 if (err)
1336 return err;
1337
435faee1
DB		 1338 /* Mark slots with STACK_MISC in case of raw mode, stack offset
1339 * is inferred from register state.
1340 */
1341 for (i = 0; i < meta.access_size; i++) {
1342 err = check_mem_access(env, meta.regno, i, BPF_B, BPF_WRITE, -1);
1343 if (err)
1344 return err;
1345 }
1346
17a52670
AS		 1347 /* reset caller saved regs */
1348 for (i = 0; i < CALLER_SAVED_REGS; i++) {
1349 reg = regs + caller_saved[i];
1350 reg->type = NOT_INIT;
1351 reg->imm = 0;
1352 }
1353
1354 /* update return register */
1355 if (fn->ret_type == RET_INTEGER) {
1356 regs[BPF_REG_0].type = UNKNOWN_VALUE;
1357 } else if (fn->ret_type == RET_VOID) {
1358 regs[BPF_REG_0].type = NOT_INIT;
1359 } else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL) {
1360 regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
48461135 1361 regs[BPF_REG_0].max_value = regs[BPF_REG_0].min_value = 0;
17a52670
AS		 1362 /* remember map_ptr, so that check_map_access()
1363 * can check 'value_size' boundary of memory access
1364 * to map element returned from bpf_map_lookup_elem()
1365 */
33ff9823 1366 if (meta.map_ptr == NULL) {
17a52670
AS		 1367 verbose("kernel subsystem misconfigured verifier\n");
1368 return -EINVAL;
1369 }
33ff9823 1370 regs[BPF_REG_0].map_ptr = meta.map_ptr;
57a09bf0 1371 regs[BPF_REG_0].id = ++env->id_gen;
17a52670 1372 } else {
ebb676da
TG		 1373 verbose("unknown return type %d of func %s#%d\n",
1374 fn->ret_type, func_id_name(func_id), func_id);
17a52670
AS		 1375 return -EINVAL;
1376 }
04fd61ab 1377
33ff9823 1378 err = check_map_func_compatibility(meta.map_ptr, func_id);
35578d79
KX		 1379 if (err)
1380 return err;
04fd61ab 1381
969bf05e
AS		 1382 if (changes_data)
1383 clear_all_pkt_pointers(env);
1384 return 0;
1385}
1386
58e2af8b
JK		 1387static int check_packet_ptr_add(struct bpf_verifier_env *env,
1388 struct bpf_insn *insn)
969bf05e 1389{
58e2af8b
JK		 1390 struct bpf_reg_state *regs = env->cur_state.regs;
1391 struct bpf_reg_state *dst_reg = &regs[insn->dst_reg];
1392 struct bpf_reg_state *src_reg = &regs[insn->src_reg];
1393 struct bpf_reg_state tmp_reg;
969bf05e
AS		 1394 s32 imm;
1395
1396 if (BPF_SRC(insn->code) == BPF_K) {
1397 /* pkt_ptr += imm */
1398 imm = insn->imm;
1399
1400add_imm:
63dfef75 1401 if (imm < 0) {
969bf05e
AS		 1402 verbose("addition of negative constant to packet pointer is not allowed\n");
1403 return -EACCES;
1404 }
1405 if (imm >= MAX_PACKET_OFF ||
1406 imm + dst_reg->off >= MAX_PACKET_OFF) {
1407 verbose("constant %d is too large to add to packet pointer\n",
1408 imm);
1409 return -EACCES;
1410 }
1411 /* a constant was added to pkt_ptr.
1412 * Remember it while keeping the same 'id'
1413 */
1414 dst_reg->off += imm;
1415 } else {
1b9b69ec
AS		 1416 if (src_reg->type == PTR_TO_PACKET) {
1417 /* R6=pkt(id=0,off=0,r=62) R7=imm22; r7 += r6 */
1418 tmp_reg = *dst_reg; /* save r7 state */
1419 *dst_reg = *src_reg; /* copy pkt_ptr state r6 into r7 */
1420 src_reg = &tmp_reg; /* pretend it's src_reg state */
1421 /* if the checks below reject it, the copy won't matter,
1422 * since we're rejecting the whole program. If all ok,
1423 * then imm22 state will be added to r7
1424 * and r7 will be pkt(id=0,off=22,r=62) while
1425 * r6 will stay as pkt(id=0,off=0,r=62)
1426 */
1427 }
1428
969bf05e
AS		 1429 if (src_reg->type == CONST_IMM) {
1430 /* pkt_ptr += reg where reg is known constant */
1431 imm = src_reg->imm;
1432 goto add_imm;
1433 }
1434 /* disallow pkt_ptr += reg
1435 * if reg is not uknown_value with guaranteed zero upper bits
1436 * otherwise pkt_ptr may overflow and addition will become
1437 * subtraction which is not allowed
1438 */
1439 if (src_reg->type != UNKNOWN_VALUE) {
1440 verbose("cannot add '%s' to ptr_to_packet\n",
1441 reg_type_str[src_reg->type]);
1442 return -EACCES;
1443 }
1444 if (src_reg->imm < 48) {
1445 verbose("cannot add integer value with %lld upper zero bits to ptr_to_packet\n",
1446 src_reg->imm);
1447 return -EACCES;
1448 }
1449 /* dst_reg stays as pkt_ptr type and since some positive
1450 * integer value was added to the pointer, increment its 'id'
1451 */
1f415a74 1452 dst_reg->id = ++env->id_gen;
969bf05e
AS		 1453
1454 /* something was added to pkt_ptr, set range and off to zero */
1455 dst_reg->off = 0;
1456 dst_reg->range = 0;
1457 }
1458 return 0;
1459}
1460
58e2af8b 1461static int evaluate_reg_alu(struct bpf_verifier_env *env, struct bpf_insn *insn)
969bf05e 1462{
58e2af8b
JK		 1463 struct bpf_reg_state *regs = env->cur_state.regs;
1464 struct bpf_reg_state *dst_reg = &regs[insn->dst_reg];
969bf05e
AS		 1465 u8 opcode = BPF_OP(insn->code);
1466 s64 imm_log2;
1467
1468 /* for type == UNKNOWN_VALUE:
1469 * imm > 0 -> number of zero upper bits
1470 * imm == 0 -> don't track which is the same as all bits can be non-zero
1471 */
1472
1473 if (BPF_SRC(insn->code) == BPF_X) {
58e2af8b 1474 struct bpf_reg_state *src_reg = &regs[insn->src_reg];
969bf05e
AS		 1475
1476 if (src_reg->type == UNKNOWN_VALUE && src_reg->imm > 0 &&
1477 dst_reg->imm && opcode == BPF_ADD) {
1478 /* dreg += sreg
1479 * where both have zero upper bits. Adding them
1480 * can only result making one more bit non-zero
1481 * in the larger value.
1482 * Ex. 0xffff (imm=48) + 1 (imm=63) = 0x10000 (imm=47)
1483 * 0xffff (imm=48) + 0xffff = 0x1fffe (imm=47)
1484 */
1485 dst_reg->imm = min(dst_reg->imm, src_reg->imm);
1486 dst_reg->imm--;
1487 return 0;
1488 }
1489 if (src_reg->type == CONST_IMM && src_reg->imm > 0 &&
1490 dst_reg->imm && opcode == BPF_ADD) {
1491 /* dreg += sreg
1492 * where dreg has zero upper bits and sreg is const.
1493 * Adding them can only result making one more bit
1494 * non-zero in the larger value.
1495 */
1496 imm_log2 = __ilog2_u64((long long)src_reg->imm);
1497 dst_reg->imm = min(dst_reg->imm, 63 - imm_log2);
1498 dst_reg->imm--;
1499 return 0;
1500 }
1501 /* all other cases non supported yet, just mark dst_reg */
1502 dst_reg->imm = 0;
1503 return 0;
1504 }
1505
1506 /* sign extend 32-bit imm into 64-bit to make sure that
1507 * negative values occupy bit 63. Note ilog2() would have
1508 * been incorrect, since sizeof(insn->imm) == 4
1509 */
1510 imm_log2 = __ilog2_u64((long long)insn->imm);
1511
1512 if (dst_reg->imm && opcode == BPF_LSH) {
1513 /* reg <<= imm
1514 * if reg was a result of 2 byte load, then its imm == 48
1515 * which means that upper 48 bits are zero and shifting this reg
1516 * left by 4 would mean that upper 44 bits are still zero
1517 */
1518 dst_reg->imm -= insn->imm;
1519 } else if (dst_reg->imm && opcode == BPF_MUL) {
1520 /* reg *= imm
1521 * if multiplying by 14 subtract 4
1522 * This is conservative calculation of upper zero bits.
1523 * It's not trying to special case insn->imm == 1 or 0 cases
1524 */
1525 dst_reg->imm -= imm_log2 + 1;
1526 } else if (opcode == BPF_AND) {
1527 /* reg &= imm */
1528 dst_reg->imm = 63 - imm_log2;
1529 } else if (dst_reg->imm && opcode == BPF_ADD) {
1530 /* reg += imm */
1531 dst_reg->imm = min(dst_reg->imm, 63 - imm_log2);
1532 dst_reg->imm--;
1533 } else if (opcode == BPF_RSH) {
1534 /* reg >>= imm
1535 * which means that after right shift, upper bits will be zero
1536 * note that verifier already checked that
1537 * 0 <= imm < 64 for shift insn
1538 */
1539 dst_reg->imm += insn->imm;
1540 if (unlikely(dst_reg->imm > 64))
1541 /* some dumb code did:
1542 * r2 = *(u32 *)mem;
1543 * r2 >>= 32;
1544 * and all bits are zero now */
1545 dst_reg->imm = 64;
1546 } else {
1547 /* all other alu ops, means that we don't know what will
1548 * happen to the value, mark it with unknown number of zero bits
1549 */
1550 dst_reg->imm = 0;
1551 }
1552
1553 if (dst_reg->imm < 0) {
1554 /* all 64 bits of the register can contain non-zero bits
1555 * and such value cannot be added to ptr_to_packet, since it
1556 * may overflow, mark it as unknown to avoid further eval
1557 */
1558 dst_reg->imm = 0;
1559 }
1560 return 0;
1561}
1562
58e2af8b
JK		 1563static int evaluate_reg_imm_alu(struct bpf_verifier_env *env,
1564 struct bpf_insn *insn)
969bf05e 1565{
58e2af8b
JK		 1566 struct bpf_reg_state *regs = env->cur_state.regs;
1567 struct bpf_reg_state *dst_reg = &regs[insn->dst_reg];
1568 struct bpf_reg_state *src_reg = &regs[insn->src_reg];
969bf05e 1569 u8 opcode = BPF_OP(insn->code);
3fadc801 1570 u64 dst_imm = dst_reg->imm;
969bf05e 1571
3fadc801
DB		 1572 /* dst_reg->type == CONST_IMM here. Simulate execution of insns
1573 * containing ALU ops. Don't care about overflow or negative
1574 * values, just add/sub/... them; registers are in u64.
969bf05e 1575 */
3fadc801
DB		 1576 if (opcode == BPF_ADD && BPF_SRC(insn->code) == BPF_K) {
1577 dst_imm += insn->imm;
1578 } else if (opcode == BPF_ADD && BPF_SRC(insn->code) == BPF_X &&
1579 src_reg->type == CONST_IMM) {
1580 dst_imm += src_reg->imm;
1581 } else if (opcode == BPF_SUB && BPF_SRC(insn->code) == BPF_K) {
1582 dst_imm -= insn->imm;
1583 } else if (opcode == BPF_SUB && BPF_SRC(insn->code) == BPF_X &&
1584 src_reg->type == CONST_IMM) {
1585 dst_imm -= src_reg->imm;
1586 } else if (opcode == BPF_MUL && BPF_SRC(insn->code) == BPF_K) {
1587 dst_imm *= insn->imm;
1588 } else if (opcode == BPF_MUL && BPF_SRC(insn->code) == BPF_X &&
1589 src_reg->type == CONST_IMM) {
1590 dst_imm *= src_reg->imm;
1591 } else if (opcode == BPF_OR && BPF_SRC(insn->code) == BPF_K) {
1592 dst_imm |= insn->imm;
1593 } else if (opcode == BPF_OR && BPF_SRC(insn->code) == BPF_X &&
1594 src_reg->type == CONST_IMM) {
1595 dst_imm |= src_reg->imm;
1596 } else if (opcode == BPF_AND && BPF_SRC(insn->code) == BPF_K) {
1597 dst_imm &= insn->imm;
1598 } else if (opcode == BPF_AND && BPF_SRC(insn->code) == BPF_X &&
1599 src_reg->type == CONST_IMM) {
1600 dst_imm &= src_reg->imm;
1601 } else if (opcode == BPF_RSH && BPF_SRC(insn->code) == BPF_K) {
1602 dst_imm >>= insn->imm;
1603 } else if (opcode == BPF_RSH && BPF_SRC(insn->code) == BPF_X &&
1604 src_reg->type == CONST_IMM) {
1605 dst_imm >>= src_reg->imm;
1606 } else if (opcode == BPF_LSH && BPF_SRC(insn->code) == BPF_K) {
1607 dst_imm <<= insn->imm;
1608 } else if (opcode == BPF_LSH && BPF_SRC(insn->code) == BPF_X &&
1609 src_reg->type == CONST_IMM) {
1610 dst_imm <<= src_reg->imm;
1611 } else {
969bf05e 1612 mark_reg_unknown_value(regs, insn->dst_reg);
3fadc801
DB		 1613 goto out;
1614 }
1615
1616 dst_reg->imm = dst_imm;
1617out:
17a52670
AS		 1618 return 0;
1619}
1620
48461135
JB		 1621static void check_reg_overflow(struct bpf_reg_state *reg)
1622{
1623 if (reg->max_value > BPF_REGISTER_MAX_RANGE)
1624 reg->max_value = BPF_REGISTER_MAX_RANGE;
f23cc643
JB		 1625 if (reg->min_value < BPF_REGISTER_MIN_RANGE ||
1626 reg->min_value > BPF_REGISTER_MAX_RANGE)
48461135
JB		 1627 reg->min_value = BPF_REGISTER_MIN_RANGE;
1628}
1629
1630static void adjust_reg_min_max_vals(struct bpf_verifier_env *env,
1631 struct bpf_insn *insn)
1632{
1633 struct bpf_reg_state *regs = env->cur_state.regs, *dst_reg;
f23cc643
JB		 1634 s64 min_val = BPF_REGISTER_MIN_RANGE;
1635 u64 max_val = BPF_REGISTER_MAX_RANGE;
48461135
JB		 1636 u8 opcode = BPF_OP(insn->code);
1637
1638 dst_reg = &regs[insn->dst_reg];
1639 if (BPF_SRC(insn->code) == BPF_X) {
1640 check_reg_overflow(&regs[insn->src_reg]);
1641 min_val = regs[insn->src_reg].min_value;
1642 max_val = regs[insn->src_reg].max_value;
1643
1644 /* If the source register is a random pointer then the
1645 * min_value/max_value values represent the range of the known
1646 * accesses into that value, not the actual min/max value of the
1647 * register itself. In this case we have to reset the reg range
1648 * values so we know it is not safe to look at.
1649 */
1650 if (regs[insn->src_reg].type != CONST_IMM &&
1651 regs[insn->src_reg].type != UNKNOWN_VALUE) {
1652 min_val = BPF_REGISTER_MIN_RANGE;
1653 max_val = BPF_REGISTER_MAX_RANGE;
1654 }
1655 } else if (insn->imm < BPF_REGISTER_MAX_RANGE &&
1656 (s64)insn->imm > BPF_REGISTER_MIN_RANGE) {
1657 min_val = max_val = insn->imm;
48461135
JB		 1658 }
1659
1660 /* We don't know anything about what was done to this register, mark it
1661 * as unknown.
1662 */
1663 if (min_val == BPF_REGISTER_MIN_RANGE &&
1664 max_val == BPF_REGISTER_MAX_RANGE) {
1665 reset_reg_range_values(regs, insn->dst_reg);
1666 return;
1667 }
1668
f23cc643
JB		 1669 /* If one of our values was at the end of our ranges then we can't just
1670 * do our normal operations to the register, we need to set the values
1671 * to the min/max since they are undefined.
1672 */
1673 if (min_val == BPF_REGISTER_MIN_RANGE)
1674 dst_reg->min_value = BPF_REGISTER_MIN_RANGE;
1675 if (max_val == BPF_REGISTER_MAX_RANGE)
1676 dst_reg->max_value = BPF_REGISTER_MAX_RANGE;
1677
48461135
JB		 1678 switch (opcode) {
1679 case BPF_ADD:
f23cc643
JB		 1680 if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE)
1681 dst_reg->min_value += min_val;
1682 if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE)
1683 dst_reg->max_value += max_val;
48461135
JB		 1684 break;
1685 case BPF_SUB:
f23cc643
JB		 1686 if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE)
1687 dst_reg->min_value -= min_val;
1688 if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE)
1689 dst_reg->max_value -= max_val;
48461135
JB		 1690 break;
1691 case BPF_MUL:
f23cc643
JB		 1692 if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE)
1693 dst_reg->min_value *= min_val;
1694 if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE)
1695 dst_reg->max_value *= max_val;
48461135
JB		 1696 break;
1697 case BPF_AND:
f23cc643
JB		 1698 /* Disallow AND'ing of negative numbers, ain't nobody got time
1699 * for that. Otherwise the minimum is 0 and the max is the max
1700 * value we could AND against.
1701 */
1702 if (min_val < 0)
1703 dst_reg->min_value = BPF_REGISTER_MIN_RANGE;
1704 else
1705 dst_reg->min_value = 0;
48461135
JB		 1706 dst_reg->max_value = max_val;
1707 break;
1708 case BPF_LSH:
1709 /* Gotta have special overflow logic here, if we're shifting
1710 * more than MAX_RANGE then just assume we have an invalid
1711 * range.
1712 */
1713 if (min_val > ilog2(BPF_REGISTER_MAX_RANGE))
1714 dst_reg->min_value = BPF_REGISTER_MIN_RANGE;
f23cc643 1715 else if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE)
48461135
JB		 1716 dst_reg->min_value <<= min_val;
1717
1718 if (max_val > ilog2(BPF_REGISTER_MAX_RANGE))
1719 dst_reg->max_value = BPF_REGISTER_MAX_RANGE;
f23cc643 1720 else if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE)
48461135
JB		 1721 dst_reg->max_value <<= max_val;
1722 break;
1723 case BPF_RSH:
f23cc643
JB		 1724 /* RSH by a negative number is undefined, and the BPF_RSH is an
1725 * unsigned shift, so make the appropriate casts.
48461135 1726 */
f23cc643
JB		 1727 if (min_val < 0 || dst_reg->min_value < 0)
1728 dst_reg->min_value = BPF_REGISTER_MIN_RANGE;
1729 else
1730 dst_reg->min_value =
1731 (u64)(dst_reg->min_value) >> min_val;
1732 if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE)
1733 dst_reg->max_value >>= max_val;
48461135
JB		 1734 break;
1735 default:
1736 reset_reg_range_values(regs, insn->dst_reg);
1737 break;
1738 }
1739
1740 check_reg_overflow(dst_reg);
1741}
1742
17a52670 1743/* check validity of 32-bit and 64-bit arithmetic operations */
58e2af8b 1744static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
17a52670 1745{
58e2af8b 1746 struct bpf_reg_state *regs = env->cur_state.regs, *dst_reg;
17a52670
AS		 1747 u8 opcode = BPF_OP(insn->code);
1748 int err;
1749
1750 if (opcode == BPF_END || opcode == BPF_NEG) {
1751 if (opcode == BPF_NEG) {
1752 if (BPF_SRC(insn->code) != 0 ||
1753 insn->src_reg != BPF_REG_0 ||
1754 insn->off != 0 || insn->imm != 0) {
1755 verbose("BPF_NEG uses reserved fields\n");
1756 return -EINVAL;
1757 }
1758 } else {
1759 if (insn->src_reg != BPF_REG_0 || insn->off != 0 ||
1760 (insn->imm != 16 && insn->imm != 32 && insn->imm != 64)) {
1761 verbose("BPF_END uses reserved fields\n");
1762 return -EINVAL;
1763 }
1764 }
1765
1766 /* check src operand */
1767 err = check_reg_arg(regs, insn->dst_reg, SRC_OP);
1768 if (err)
1769 return err;
1770
1be7f75d
AS		 1771 if (is_pointer_value(env, insn->dst_reg)) {
1772 verbose("R%d pointer arithmetic prohibited\n",
1773 insn->dst_reg);
1774 return -EACCES;
1775 }
1776
17a52670
AS		 1777 /* check dest operand */
1778 err = check_reg_arg(regs, insn->dst_reg, DST_OP);
1779 if (err)
1780 return err;
1781
1782 } else if (opcode == BPF_MOV) {
1783
1784 if (BPF_SRC(insn->code) == BPF_X) {
1785 if (insn->imm != 0 || insn->off != 0) {
1786 verbose("BPF_MOV uses reserved fields\n");
1787 return -EINVAL;
1788 }
1789
1790 /* check src operand */
1791 err = check_reg_arg(regs, insn->src_reg, SRC_OP);
1792 if (err)
1793 return err;
1794 } else {
1795 if (insn->src_reg != BPF_REG_0 || insn->off != 0) {
1796 verbose("BPF_MOV uses reserved fields\n");
1797 return -EINVAL;
1798 }
1799 }
1800
1801 /* check dest operand */
1802 err = check_reg_arg(regs, insn->dst_reg, DST_OP);
1803 if (err)
1804 return err;
1805
48461135
JB		 1806 /* we are setting our register to something new, we need to
1807 * reset its range values.
1808 */
1809 reset_reg_range_values(regs, insn->dst_reg);
1810
17a52670
AS		 1811 if (BPF_SRC(insn->code) == BPF_X) {
1812 if (BPF_CLASS(insn->code) == BPF_ALU64) {
1813 /* case: R1 = R2
1814 * copy register state to dest reg
1815 */
1816 regs[insn->dst_reg] = regs[insn->src_reg];
1817 } else {
1be7f75d
AS		 1818 if (is_pointer_value(env, insn->src_reg)) {
1819 verbose("R%d partial copy of pointer\n",
1820 insn->src_reg);
1821 return -EACCES;
1822 }
57a09bf0 1823 mark_reg_unknown_value(regs, insn->dst_reg);
17a52670
AS		 1824 }
1825 } else {
1826 /* case: R = imm
1827 * remember the value we stored into this reg
1828 */
1829 regs[insn->dst_reg].type = CONST_IMM;
1830 regs[insn->dst_reg].imm = insn->imm;
48461135
JB		 1831 regs[insn->dst_reg].max_value = insn->imm;
1832 regs[insn->dst_reg].min_value = insn->imm;
17a52670
AS		 1833 }
1834
1835 } else if (opcode > BPF_END) {
1836 verbose("invalid BPF_ALU opcode %x\n", opcode);
1837 return -EINVAL;
1838
1839 } else { /* all other ALU ops: and, sub, xor, add, ... */
1840
17a52670
AS		 1841 if (BPF_SRC(insn->code) == BPF_X) {
1842 if (insn->imm != 0 || insn->off != 0) {
1843 verbose("BPF_ALU uses reserved fields\n");
1844 return -EINVAL;
1845 }
1846 /* check src1 operand */
1847 err = check_reg_arg(regs, insn->src_reg, SRC_OP);
1848 if (err)
1849 return err;
1850 } else {
1851 if (insn->src_reg != BPF_REG_0 || insn->off != 0) {
1852 verbose("BPF_ALU uses reserved fields\n");
1853 return -EINVAL;
1854 }
1855 }
1856
1857 /* check src2 operand */
1858 err = check_reg_arg(regs, insn->dst_reg, SRC_OP);
1859 if (err)
1860 return err;
1861
1862 if ((opcode == BPF_MOD || opcode == BPF_DIV) &&
1863 BPF_SRC(insn->code) == BPF_K && insn->imm == 0) {
1864 verbose("div by zero\n");
1865 return -EINVAL;
1866 }
1867
229394e8
RV		 1868 if ((opcode == BPF_LSH || opcode == BPF_RSH ||
1869 opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) {
1870 int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32;
1871
1872 if (insn->imm < 0 || insn->imm >= size) {
1873 verbose("invalid shift %d\n", insn->imm);
1874 return -EINVAL;
1875 }
1876 }
1877
1a0dc1ac
AS		 1878 /* check dest operand */
1879 err = check_reg_arg(regs, insn->dst_reg, DST_OP_NO_MARK);
1880 if (err)
1881 return err;
1882
1883 dst_reg = &regs[insn->dst_reg];
1884
48461135
JB		 1885 /* first we want to adjust our ranges. */
1886 adjust_reg_min_max_vals(env, insn);
1887
17a52670
AS		 1888 /* pattern match 'bpf_add Rx, imm' instruction */
1889 if (opcode == BPF_ADD && BPF_CLASS(insn->code) == BPF_ALU64 &&
1a0dc1ac
AS		 1890 dst_reg->type == FRAME_PTR && BPF_SRC(insn->code) == BPF_K) {
1891 dst_reg->type = PTR_TO_STACK;
1892 dst_reg->imm = insn->imm;
1893 return 0;
969bf05e
AS		 1894 } else if (opcode == BPF_ADD &&
1895 BPF_CLASS(insn->code) == BPF_ALU64 &&
1b9b69ec
AS		 1896 (dst_reg->type == PTR_TO_PACKET ||
1897 (BPF_SRC(insn->code) == BPF_X &&
1898 regs[insn->src_reg].type == PTR_TO_PACKET))) {
969bf05e
AS		 1899 /* ptr_to_packet += K|X */
1900 return check_packet_ptr_add(env, insn);
1901 } else if (BPF_CLASS(insn->code) == BPF_ALU64 &&
1902 dst_reg->type == UNKNOWN_VALUE &&
1903 env->allow_ptr_leaks) {
1904 /* unknown += K|X */
1905 return evaluate_reg_alu(env, insn);
1906 } else if (BPF_CLASS(insn->code) == BPF_ALU64 &&
1907 dst_reg->type == CONST_IMM &&
1908 env->allow_ptr_leaks) {
1909 /* reg_imm += K|X */
1910 return evaluate_reg_imm_alu(env, insn);
1be7f75d
AS		 1911 } else if (is_pointer_value(env, insn->dst_reg)) {
1912 verbose("R%d pointer arithmetic prohibited\n",
1913 insn->dst_reg);
1914 return -EACCES;
1915 } else if (BPF_SRC(insn->code) == BPF_X &&
1916 is_pointer_value(env, insn->src_reg)) {
1917 verbose("R%d pointer arithmetic prohibited\n",
1918 insn->src_reg);
1919 return -EACCES;
1920 }
17a52670 1921
48461135
JB		 1922 /* If we did pointer math on a map value then just set it to our
1923 * PTR_TO_MAP_VALUE_ADJ type so we can deal with any stores or
1924 * loads to this register appropriately, otherwise just mark the
1925 * register as unknown.
1926 */
1927 if (env->allow_ptr_leaks &&
1928 (dst_reg->type == PTR_TO_MAP_VALUE ||
1929 dst_reg->type == PTR_TO_MAP_VALUE_ADJ))
1930 dst_reg->type = PTR_TO_MAP_VALUE_ADJ;
1931 else
1932 mark_reg_unknown_value(regs, insn->dst_reg);
17a52670
AS		 1933 }
1934
1935 return 0;
1936}
1937
58e2af8b
JK		 1938static void find_good_pkt_pointers(struct bpf_verifier_state *state,
1939 struct bpf_reg_state *dst_reg)
969bf05e 1940{
58e2af8b 1941 struct bpf_reg_state *regs = state->regs, *reg;
969bf05e 1942 int i;
2d2be8ca
DB		 1943
1944 /* LLVM can generate two kind of checks:
1945 *
1946 * Type 1:
1947 *
1948 * r2 = r3;
1949 * r2 += 8;
1950 * if (r2 > pkt_end) goto <handle exception>
1951 * <access okay>
1952 *
1953 * Where:
1954 * r2 == dst_reg, pkt_end == src_reg
1955 * r2=pkt(id=n,off=8,r=0)
1956 * r3=pkt(id=n,off=0,r=0)
1957 *
1958 * Type 2:
1959 *
1960 * r2 = r3;
1961 * r2 += 8;
1962 * if (pkt_end >= r2) goto <access okay>
1963 * <handle exception>
1964 *
1965 * Where:
1966 * pkt_end == dst_reg, r2 == src_reg
1967 * r2=pkt(id=n,off=8,r=0)
1968 * r3=pkt(id=n,off=0,r=0)
1969 *
1970 * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8)
1971 * so that range of bytes [r3, r3 + 8) is safe to access.
969bf05e 1972 */
2d2be8ca 1973
969bf05e
AS		 1974 for (i = 0; i < MAX_BPF_REG; i++)
1975 if (regs[i].type == PTR_TO_PACKET && regs[i].id == dst_reg->id)
1976 regs[i].range = dst_reg->off;
1977
1978 for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) {
1979 if (state->stack_slot_type[i] != STACK_SPILL)
1980 continue;
1981 reg = &state->spilled_regs[i / BPF_REG_SIZE];
1982 if (reg->type == PTR_TO_PACKET && reg->id == dst_reg->id)
1983 reg->range = dst_reg->off;
1984 }
1985}
1986
48461135
JB		 1987/* Adjusts the register min/max values in the case that the dst_reg is the
1988 * variable register that we are working on, and src_reg is a constant or we're
1989 * simply doing a BPF_K check.
1990 */
1991static void reg_set_min_max(struct bpf_reg_state *true_reg,
1992 struct bpf_reg_state *false_reg, u64 val,
1993 u8 opcode)
1994{
1995 switch (opcode) {
1996 case BPF_JEQ:
1997 /* If this is false then we know nothing Jon Snow, but if it is
1998 * true then we know for sure.
1999 */
2000 true_reg->max_value = true_reg->min_value = val;
2001 break;
2002 case BPF_JNE:
2003 /* If this is true we know nothing Jon Snow, but if it is false
2004 * we know the value for sure;
2005 */
2006 false_reg->max_value = false_reg->min_value = val;
2007 break;
2008 case BPF_JGT:
2009 /* Unsigned comparison, the minimum value is 0. */
2010 false_reg->min_value = 0;
7e57fbb2 2011 /* fallthrough */
48461135
JB		 2012 case BPF_JSGT:
2013 /* If this is false then we know the maximum val is val,
2014 * otherwise we know the min val is val+1.
2015 */
2016 false_reg->max_value = val;
2017 true_reg->min_value = val + 1;
2018 break;
2019 case BPF_JGE:
2020 /* Unsigned comparison, the minimum value is 0. */
2021 false_reg->min_value = 0;
7e57fbb2 2022 /* fallthrough */
48461135
JB		 2023 case BPF_JSGE:
2024 /* If this is false then we know the maximum value is val - 1,
2025 * otherwise we know the mimimum value is val.
2026 */
2027 false_reg->max_value = val - 1;
2028 true_reg->min_value = val;
2029 break;
2030 default:
2031 break;
2032 }
2033
2034 check_reg_overflow(false_reg);
2035 check_reg_overflow(true_reg);
2036}
2037
2038/* Same as above, but for the case that dst_reg is a CONST_IMM reg and src_reg
2039 * is the variable reg.
2040 */
2041static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
2042 struct bpf_reg_state *false_reg, u64 val,
2043 u8 opcode)
2044{
2045 switch (opcode) {
2046 case BPF_JEQ:
2047 /* If this is false then we know nothing Jon Snow, but if it is
2048 * true then we know for sure.
2049 */
2050 true_reg->max_value = true_reg->min_value = val;
2051 break;
2052 case BPF_JNE:
2053 /* If this is true we know nothing Jon Snow, but if it is false
2054 * we know the value for sure;
2055 */
2056 false_reg->max_value = false_reg->min_value = val;
2057 break;
2058 case BPF_JGT:
2059 /* Unsigned comparison, the minimum value is 0. */
2060 true_reg->min_value = 0;
7e57fbb2 2061 /* fallthrough */
48461135
JB		 2062 case BPF_JSGT:
2063 /*
2064 * If this is false, then the val is <= the register, if it is
2065 * true the register <= to the val.
2066 */
2067 false_reg->min_value = val;
2068 true_reg->max_value = val - 1;
2069 break;
2070 case BPF_JGE:
2071 /* Unsigned comparison, the minimum value is 0. */
2072 true_reg->min_value = 0;
7e57fbb2 2073 /* fallthrough */
48461135
JB		 2074 case BPF_JSGE:
2075 /* If this is false then constant < register, if it is true then
2076 * the register < constant.
2077 */
2078 false_reg->min_value = val + 1;
2079 true_reg->max_value = val;
2080 break;
2081 default:
2082 break;
2083 }
2084
2085 check_reg_overflow(false_reg);
2086 check_reg_overflow(true_reg);
2087}
2088
57a09bf0
TG		 2089static void mark_map_reg(struct bpf_reg_state *regs, u32 regno, u32 id,
2090 enum bpf_reg_type type)
2091{
2092 struct bpf_reg_state *reg = &regs[regno];
2093
2094 if (reg->type == PTR_TO_MAP_VALUE_OR_NULL && reg->id == id) {
2095 reg->type = type;
a08dd0da
DB		 2096 /* We don't need id from this point onwards anymore, thus we
2097 * should better reset it, so that state pruning has chances
2098 * to take effect.
2099 */
2100 reg->id = 0;
57a09bf0 2101 if (type == UNKNOWN_VALUE)
6760bf2d 2102 __mark_reg_unknown_value(regs, regno);
57a09bf0
TG		 2103 }
2104}
2105
2106/* The logic is similar to find_good_pkt_pointers(), both could eventually
2107 * be folded together at some point.
2108 */
2109static void mark_map_regs(struct bpf_verifier_state *state, u32 regno,
2110 enum bpf_reg_type type)
2111{
2112 struct bpf_reg_state *regs = state->regs;
a08dd0da 2113 u32 id = regs[regno].id;
57a09bf0
TG		 2114 int i;
2115
2116 for (i = 0; i < MAX_BPF_REG; i++)
a08dd0da 2117 mark_map_reg(regs, i, id, type);
57a09bf0
TG		 2118
2119 for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) {
2120 if (state->stack_slot_type[i] != STACK_SPILL)
2121 continue;
a08dd0da 2122 mark_map_reg(state->spilled_regs, i / BPF_REG_SIZE, id, type);
57a09bf0
TG		 2123 }
2124}
2125
58e2af8b 2126static int check_cond_jmp_op(struct bpf_verifier_env *env,
17a52670
AS		 2127 struct bpf_insn *insn, int *insn_idx)
2128{
58e2af8b
JK		 2129 struct bpf_verifier_state *other_branch, *this_branch = &env->cur_state;
2130 struct bpf_reg_state *regs = this_branch->regs, *dst_reg;
17a52670
AS		 2131 u8 opcode = BPF_OP(insn->code);
2132 int err;
2133
2134 if (opcode > BPF_EXIT) {
2135 verbose("invalid BPF_JMP opcode %x\n", opcode);
2136 return -EINVAL;
2137 }
2138
2139 if (BPF_SRC(insn->code) == BPF_X) {
2140 if (insn->imm != 0) {
2141 verbose("BPF_JMP uses reserved fields\n");
2142 return -EINVAL;
2143 }
2144
2145 /* check src1 operand */
2146 err = check_reg_arg(regs, insn->src_reg, SRC_OP);
2147 if (err)
2148 return err;
1be7f75d
AS		 2149
2150 if (is_pointer_value(env, insn->src_reg)) {
2151 verbose("R%d pointer comparison prohibited\n",
2152 insn->src_reg);
2153 return -EACCES;
2154 }
17a52670
AS		 2155 } else {
2156 if (insn->src_reg != BPF_REG_0) {
2157 verbose("BPF_JMP uses reserved fields\n");
2158 return -EINVAL;
2159 }
2160 }
2161
2162 /* check src2 operand */
2163 err = check_reg_arg(regs, insn->dst_reg, SRC_OP);
2164 if (err)
2165 return err;
2166
1a0dc1ac
AS		 2167 dst_reg = &regs[insn->dst_reg];
2168
17a52670
AS		 2169 /* detect if R == 0 where R was initialized to zero earlier */
2170 if (BPF_SRC(insn->code) == BPF_K &&
2171 (opcode == BPF_JEQ || opcode == BPF_JNE) &&
1a0dc1ac 2172 dst_reg->type == CONST_IMM && dst_reg->imm == insn->imm) {
17a52670
AS		 2173 if (opcode == BPF_JEQ) {
2174 /* if (imm == imm) goto pc+off;
2175 * only follow the goto, ignore fall-through
2176 */
2177 *insn_idx += insn->off;
2178 return 0;
2179 } else {
2180 /* if (imm != imm) goto pc+off;
2181 * only follow fall-through branch, since
2182 * that's where the program will go
2183 */
2184 return 0;
2185 }
2186 }
2187
2188 other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx);
2189 if (!other_branch)
2190 return -EFAULT;
2191
48461135
JB		 2192 /* detect if we are comparing against a constant value so we can adjust
2193 * our min/max values for our dst register.
2194 */
2195 if (BPF_SRC(insn->code) == BPF_X) {
2196 if (regs[insn->src_reg].type == CONST_IMM)
2197 reg_set_min_max(&other_branch->regs[insn->dst_reg],
2198 dst_reg, regs[insn->src_reg].imm,
2199 opcode);
2200 else if (dst_reg->type == CONST_IMM)
2201 reg_set_min_max_inv(&other_branch->regs[insn->src_reg],
2202 &regs[insn->src_reg], dst_reg->imm,
2203 opcode);
2204 } else {
2205 reg_set_min_max(&other_branch->regs[insn->dst_reg],
2206 dst_reg, insn->imm, opcode);
2207 }
2208
58e2af8b 2209 /* detect if R == 0 where R is returned from bpf_map_lookup_elem() */
17a52670 2210 if (BPF_SRC(insn->code) == BPF_K &&
1a0dc1ac
AS		 2211 insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) &&
2212 dst_reg->type == PTR_TO_MAP_VALUE_OR_NULL) {
57a09bf0
TG		 2213 /* Mark all identical map registers in each branch as either
2214 * safe or unknown depending R == 0 or R != 0 conditional.
2215 */
2216 mark_map_regs(this_branch, insn->dst_reg,
2217 opcode == BPF_JEQ ? PTR_TO_MAP_VALUE : UNKNOWN_VALUE);
2218 mark_map_regs(other_branch, insn->dst_reg,
2219 opcode == BPF_JEQ ? UNKNOWN_VALUE : PTR_TO_MAP_VALUE);
969bf05e
AS		 2220 } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGT &&
2221 dst_reg->type == PTR_TO_PACKET &&
2222 regs[insn->src_reg].type == PTR_TO_PACKET_END) {
2d2be8ca
DB		 2223 find_good_pkt_pointers(this_branch, dst_reg);
2224 } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGE &&
2225 dst_reg->type == PTR_TO_PACKET_END &&
2226 regs[insn->src_reg].type == PTR_TO_PACKET) {
2227 find_good_pkt_pointers(other_branch, &regs[insn->src_reg]);
1be7f75d
AS		 2228 } else if (is_pointer_value(env, insn->dst_reg)) {
2229 verbose("R%d pointer comparison prohibited\n", insn->dst_reg);
2230 return -EACCES;
17a52670
AS		 2231 }
2232 if (log_level)
2d2be8ca 2233 print_verifier_state(this_branch);
17a52670
AS		 2234 return 0;
2235}
2236
0246e64d
AS		 2237/* return the map pointer stored inside BPF_LD_IMM64 instruction */
2238static struct bpf_map *ld_imm64_to_map_ptr(struct bpf_insn *insn)
2239{
2240 u64 imm64 = ((u64) (u32) insn[0].imm) | ((u64) (u32) insn[1].imm) << 32;
2241
2242 return (struct bpf_map *) (unsigned long) imm64;
2243}
2244
17a52670 2245/* verify BPF_LD_IMM64 instruction */
58e2af8b 2246static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
17a52670 2247{
58e2af8b 2248 struct bpf_reg_state *regs = env->cur_state.regs;
17a52670
AS		 2249 int err;
2250
2251 if (BPF_SIZE(insn->code) != BPF_DW) {
2252 verbose("invalid BPF_LD_IMM insn\n");
2253 return -EINVAL;
2254 }
2255 if (insn->off != 0) {
2256 verbose("BPF_LD_IMM64 uses reserved fields\n");
2257 return -EINVAL;
2258 }
2259
2260 err = check_reg_arg(regs, insn->dst_reg, DST_OP);
2261 if (err)
2262 return err;
2263
6b173873 2264 if (insn->src_reg == 0) {
6b173873
JK		 2265 u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
2266
6b173873
JK		 2267 regs[insn->dst_reg].type = CONST_IMM;
2268 regs[insn->dst_reg].imm = imm;
17a52670 2269 return 0;
6b173873 2270 }
17a52670
AS		 2271
2272 /* replace_map_fd_with_map_ptr() should have caught bad ld_imm64 */
2273 BUG_ON(insn->src_reg != BPF_PSEUDO_MAP_FD);
2274
2275 regs[insn->dst_reg].type = CONST_PTR_TO_MAP;
2276 regs[insn->dst_reg].map_ptr = ld_imm64_to_map_ptr(insn);
2277 return 0;
2278}
2279
96be4325
DB		 2280static bool may_access_skb(enum bpf_prog_type type)
2281{
2282 switch (type) {
2283 case BPF_PROG_TYPE_SOCKET_FILTER:
2284 case BPF_PROG_TYPE_SCHED_CLS:
94caee8c 2285 case BPF_PROG_TYPE_SCHED_ACT:
96be4325
DB		 2286 return true;
2287 default:
2288 return false;
2289 }
2290}
2291
ddd872bc
AS		 2292/* verify safety of LD_ABS|LD_IND instructions:
2293 * - they can only appear in the programs where ctx == skb
2294 * - since they are wrappers of function calls, they scratch R1-R5 registers,
2295 * preserve R6-R9, and store return value into R0
2296 *
2297 * Implicit input:
2298 * ctx == skb == R6 == CTX
2299 *
2300 * Explicit input:
2301 * SRC == any register
2302 * IMM == 32-bit immediate
2303 *
2304 * Output:
2305 * R0 - 8/16/32-bit skb data converted to cpu endianness
2306 */
58e2af8b 2307static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn)
ddd872bc 2308{
58e2af8b 2309 struct bpf_reg_state *regs = env->cur_state.regs;
ddd872bc 2310 u8 mode = BPF_MODE(insn->code);
58e2af8b 2311 struct bpf_reg_state *reg;
ddd872bc
AS		 2312 int i, err;
2313
24701ece 2314 if (!may_access_skb(env->prog->type)) {
1a0dc1ac 2315 verbose("BPF_LD_[ABS|IND] instructions not allowed for this program type\n");
ddd872bc
AS		 2316 return -EINVAL;
2317 }
2318
2319 if (insn->dst_reg != BPF_REG_0 || insn->off != 0 ||
d82bccc6 2320 BPF_SIZE(insn->code) == BPF_DW ||
ddd872bc 2321 (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) {
1a0dc1ac 2322 verbose("BPF_LD_[ABS|IND] uses reserved fields\n");
ddd872bc
AS		 2323 return -EINVAL;
2324 }
2325
2326 /* check whether implicit source operand (register R6) is readable */
2327 err = check_reg_arg(regs, BPF_REG_6, SRC_OP);
2328 if (err)
2329 return err;
2330
2331 if (regs[BPF_REG_6].type != PTR_TO_CTX) {
2332 verbose("at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
2333 return -EINVAL;
2334 }
2335
2336 if (mode == BPF_IND) {
2337 /* check explicit source operand */
2338 err = check_reg_arg(regs, insn->src_reg, SRC_OP);
2339 if (err)
2340 return err;
2341 }
2342
2343 /* reset caller saved regs to unreadable */
2344 for (i = 0; i < CALLER_SAVED_REGS; i++) {
2345 reg = regs + caller_saved[i];
2346 reg->type = NOT_INIT;
2347 reg->imm = 0;
2348 }
2349
2350 /* mark destination R0 register as readable, since it contains
2351 * the value fetched from the packet
2352 */
2353 regs[BPF_REG_0].type = UNKNOWN_VALUE;
2354 return 0;
2355}
2356
475fb78f
AS		 2357/* non-recursive DFS pseudo code
2358 * 1 procedure DFS-iterative(G,v):
2359 * 2 label v as discovered
2360 * 3 let S be a stack
2361 * 4 S.push(v)
2362 * 5 while S is not empty
2363 * 6 t <- S.pop()
2364 * 7 if t is what we're looking for:
2365 * 8 return t
2366 * 9 for all edges e in G.adjacentEdges(t) do
2367 * 10 if edge e is already labelled
2368 * 11 continue with the next edge
2369 * 12 w <- G.adjacentVertex(t,e)
2370 * 13 if vertex w is not discovered and not explored
2371 * 14 label e as tree-edge
2372 * 15 label w as discovered
2373 * 16 S.push(w)
2374 * 17 continue at 5
2375 * 18 else if vertex w is discovered
2376 * 19 label e as back-edge
2377 * 20 else
2378 * 21 // vertex w is explored
2379 * 22 label e as forward- or cross-edge
2380 * 23 label t as explored
2381 * 24 S.pop()
2382 *
2383 * convention:
2384 * 0x10 - discovered
2385 * 0x11 - discovered and fall-through edge labelled
2386 * 0x12 - discovered and fall-through and branch edges labelled
2387 * 0x20 - explored
2388 */
2389
2390enum {
2391 DISCOVERED = 0x10,
2392 EXPLORED = 0x20,
2393 FALLTHROUGH = 1,
2394 BRANCH = 2,
2395};
2396
58e2af8b 2397#define STATE_LIST_MARK ((struct bpf_verifier_state_list *) -1L)
f1bca824 2398
475fb78f
AS		 2399static int *insn_stack; /* stack of insns to process */
2400static int cur_stack; /* current stack index */
2401static int *insn_state;
2402
2403/* t, w, e - match pseudo-code above:
2404 * t - index of current instruction
2405 * w - next instruction
2406 * e - edge
2407 */
58e2af8b 2408static int push_insn(int t, int w, int e, struct bpf_verifier_env *env)
475fb78f
AS		 2409{
2410 if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH))
2411 return 0;
2412
2413 if (e == BRANCH && insn_state[t] >= (DISCOVERED | BRANCH))
2414 return 0;
2415
2416 if (w < 0 || w >= env->prog->len) {
2417 verbose("jump out of range from insn %d to %d\n", t, w);
2418 return -EINVAL;
2419 }
2420
f1bca824
AS		 2421 if (e == BRANCH)
2422 /* mark branch target for state pruning */
2423 env->explored_states[w] = STATE_LIST_MARK;
2424
475fb78f
AS		 2425 if (insn_state[w] == 0) {
2426 /* tree-edge */
2427 insn_state[t] = DISCOVERED | e;
2428 insn_state[w] = DISCOVERED;
2429 if (cur_stack >= env->prog->len)
2430 return -E2BIG;
2431 insn_stack[cur_stack++] = w;
2432 return 1;
2433 } else if ((insn_state[w] & 0xF0) == DISCOVERED) {
2434 verbose("back-edge from insn %d to %d\n", t, w);
2435 return -EINVAL;
2436 } else if (insn_state[w] == EXPLORED) {
2437 /* forward- or cross-edge */
2438 insn_state[t] = DISCOVERED | e;
2439 } else {
2440 verbose("insn state internal bug\n");
2441 return -EFAULT;
2442 }
2443 return 0;
2444}
2445
2446/* non-recursive depth-first-search to detect loops in BPF program
2447 * loop == back-edge in directed graph
2448 */
58e2af8b 2449static int check_cfg(struct bpf_verifier_env *env)
475fb78f
AS		 2450{
2451 struct bpf_insn *insns = env->prog->insnsi;
2452 int insn_cnt = env->prog->len;
2453 int ret = 0;
2454 int i, t;
2455
2456 insn_state = kcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
2457 if (!insn_state)
2458 return -ENOMEM;
2459
2460 insn_stack = kcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
2461 if (!insn_stack) {
2462 kfree(insn_state);
2463 return -ENOMEM;
2464 }
2465
2466 insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */
2467 insn_stack[0] = 0; /* 0 is the first instruction */
2468 cur_stack = 1;
2469
2470peek_stack:
2471 if (cur_stack == 0)
2472 goto check_state;
2473 t = insn_stack[cur_stack - 1];
2474
2475 if (BPF_CLASS(insns[t].code) == BPF_JMP) {
2476 u8 opcode = BPF_OP(insns[t].code);
2477
2478 if (opcode == BPF_EXIT) {
2479 goto mark_explored;
2480 } else if (opcode == BPF_CALL) {
2481 ret = push_insn(t, t + 1, FALLTHROUGH, env);
2482 if (ret == 1)
2483 goto peek_stack;
2484 else if (ret < 0)
2485 goto err_free;
07016151
DB		 2486 if (t + 1 < insn_cnt)
2487 env->explored_states[t + 1] = STATE_LIST_MARK;
475fb78f
AS		 2488 } else if (opcode == BPF_JA) {
2489 if (BPF_SRC(insns[t].code) != BPF_K) {
2490 ret = -EINVAL;
2491 goto err_free;
2492 }
2493 /* unconditional jump with single edge */
2494 ret = push_insn(t, t + insns[t].off + 1,
2495 FALLTHROUGH, env);
2496 if (ret == 1)
2497 goto peek_stack;
2498 else if (ret < 0)
2499 goto err_free;
f1bca824
AS		 2500 /* tell verifier to check for equivalent states
2501 * after every call and jump
2502 */
c3de6317
AS		 2503 if (t + 1 < insn_cnt)
2504 env->explored_states[t + 1] = STATE_LIST_MARK;
475fb78f
AS		 2505 } else {
2506 /* conditional jump with two edges */
2507 ret = push_insn(t, t + 1, FALLTHROUGH, env);
2508 if (ret == 1)
2509 goto peek_stack;
2510 else if (ret < 0)
2511 goto err_free;
2512
2513 ret = push_insn(t, t + insns[t].off + 1, BRANCH, env);
2514 if (ret == 1)
2515 goto peek_stack;
2516 else if (ret < 0)
2517 goto err_free;
2518 }
2519 } else {
2520 /* all other non-branch instructions with single
2521 * fall-through edge
2522 */
2523 ret = push_insn(t, t + 1, FALLTHROUGH, env);
2524 if (ret == 1)
2525 goto peek_stack;
2526 else if (ret < 0)
2527 goto err_free;
2528 }
2529
2530mark_explored:
2531 insn_state[t] = EXPLORED;
2532 if (cur_stack-- <= 0) {
2533 verbose("pop stack internal bug\n");
2534 ret = -EFAULT;
2535 goto err_free;
2536 }
2537 goto peek_stack;
2538
2539check_state:
2540 for (i = 0; i < insn_cnt; i++) {
2541 if (insn_state[i] != EXPLORED) {
2542 verbose("unreachable insn %d\n", i);
2543 ret = -EINVAL;
2544 goto err_free;
2545 }
2546 }
2547 ret = 0; /* cfg looks good */
2548
2549err_free:
2550 kfree(insn_state);
2551 kfree(insn_stack);
2552 return ret;
2553}
2554
969bf05e
AS		 2555/* the following conditions reduce the number of explored insns
2556 * from ~140k to ~80k for ultra large programs that use a lot of ptr_to_packet
2557 */
58e2af8b
JK		 2558static bool compare_ptrs_to_packet(struct bpf_reg_state *old,
2559 struct bpf_reg_state *cur)
969bf05e
AS		 2560{
2561 if (old->id != cur->id)
2562 return false;
2563
2564 /* old ptr_to_packet is more conservative, since it allows smaller
2565 * range. Ex:
2566 * old(off=0,r=10) is equal to cur(off=0,r=20), because
2567 * old(off=0,r=10) means that with range=10 the verifier proceeded
2568 * further and found no issues with the program. Now we're in the same
2569 * spot with cur(off=0,r=20), so we're safe too, since anything further
2570 * will only be looking at most 10 bytes after this pointer.
2571 */
2572 if (old->off == cur->off && old->range < cur->range)
2573 return true;
2574
2575 /* old(off=20,r=10) is equal to cur(off=22,re=22 or 5 or 0)
2576 * since both cannot be used for packet access and safe(old)
2577 * pointer has smaller off that could be used for further
2578 * 'if (ptr > data_end)' check
2579 * Ex:
2580 * old(off=20,r=10) and cur(off=22,r=22) and cur(off=22,r=0) mean
2581 * that we cannot access the packet.
2582 * The safe range is:
2583 * [ptr, ptr + range - off)
2584 * so whenever off >=range, it means no safe bytes from this pointer.
2585 * When comparing old->off <= cur->off, it means that older code
2586 * went with smaller offset and that offset was later
2587 * used to figure out the safe range after 'if (ptr > data_end)' check
2588 * Say, 'old' state was explored like:
2589 * ... R3(off=0, r=0)
2590 * R4 = R3 + 20
2591 * ... now R4(off=20,r=0) <-- here
2592 * if (R4 > data_end)
2593 * ... R4(off=20,r=20), R3(off=0,r=20) and R3 can be used to access.
2594 * ... the code further went all the way to bpf_exit.
2595 * Now the 'cur' state at the mark 'here' has R4(off=30,r=0).
2596 * old_R4(off=20,r=0) equal to cur_R4(off=30,r=0), since if the verifier
2597 * goes further, such cur_R4 will give larger safe packet range after
2598 * 'if (R4 > data_end)' and all further insn were already good with r=20,
2599 * so they will be good with r=30 and we can prune the search.
2600 */
2601 if (old->off <= cur->off &&
2602 old->off >= old->range && cur->off >= cur->range)
2603 return true;
2604
2605 return false;
2606}
2607
f1bca824
AS		 2608/* compare two verifier states
2609 *
2610 * all states stored in state_list are known to be valid, since
2611 * verifier reached 'bpf_exit' instruction through them
2612 *
2613 * this function is called when verifier exploring different branches of
2614 * execution popped from the state stack. If it sees an old state that has
2615 * more strict register state and more strict stack state then this execution
2616 * branch doesn't need to be explored further, since verifier already
2617 * concluded that more strict state leads to valid finish.
2618 *
2619 * Therefore two states are equivalent if register state is more conservative
2620 * and explored stack state is more conservative than the current one.
2621 * Example:
2622 * explored current
2623 * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC)
2624 * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC)
2625 *
2626 * In other words if current stack state (one being explored) has more
2627 * valid slots than old one that already passed validation, it means
2628 * the verifier can stop exploring and conclude that current state is valid too
2629 *
2630 * Similarly with registers. If explored state has register type as invalid
2631 * whereas register type in current state is meaningful, it means that
2632 * the current state will reach 'bpf_exit' instruction safely
2633 */
48461135
JB		 2634static bool states_equal(struct bpf_verifier_env *env,
2635 struct bpf_verifier_state *old,
58e2af8b 2636 struct bpf_verifier_state *cur)
f1bca824 2637{
e2d2afe1 2638 bool varlen_map_access = env->varlen_map_value_access;
58e2af8b 2639 struct bpf_reg_state *rold, *rcur;
f1bca824
AS		 2640 int i;
2641
2642 for (i = 0; i < MAX_BPF_REG; i++) {
1a0dc1ac
AS		 2643 rold = &old->regs[i];
2644 rcur = &cur->regs[i];
2645
2646 if (memcmp(rold, rcur, sizeof(*rold)) == 0)
2647 continue;
2648
48461135
JB		 2649 /* If the ranges were not the same, but everything else was and
2650 * we didn't do a variable access into a map then we are a-ok.
2651 */
e2d2afe1 2652 if (!varlen_map_access &&
d2a4dd37 2653 memcmp(rold, rcur, offsetofend(struct bpf_reg_state, id)) == 0)
48461135
JB		 2654 continue;
2655
e2d2afe1
JB		 2656 /* If we didn't map access then again we don't care about the
2657 * mismatched range values and it's ok if our old type was
2658 * UNKNOWN and we didn't go to a NOT_INIT'ed reg.
2659 */
1a0dc1ac 2660 if (rold->type == NOT_INIT ||
e2d2afe1
JB		 2661 (!varlen_map_access && rold->type == UNKNOWN_VALUE &&
2662 rcur->type != NOT_INIT))
1a0dc1ac
AS		 2663 continue;
2664
969bf05e
AS		 2665 if (rold->type == PTR_TO_PACKET && rcur->type == PTR_TO_PACKET &&
2666 compare_ptrs_to_packet(rold, rcur))
2667 continue;
2668
1a0dc1ac 2669 return false;
f1bca824
AS		 2670 }
2671
2672 for (i = 0; i < MAX_BPF_STACK; i++) {
9c399760
AS		 2673 if (old->stack_slot_type[i] == STACK_INVALID)
2674 continue;
2675 if (old->stack_slot_type[i] != cur->stack_slot_type[i])
2676 /* Ex: old explored (safe) state has STACK_SPILL in
2677 * this stack slot, but current has has STACK_MISC ->
2678 * this verifier states are not equivalent,
2679 * return false to continue verification of this path
2680 */
f1bca824 2681 return false;
9c399760
AS		 2682 if (i % BPF_REG_SIZE)
2683 continue;
2684 if (memcmp(&old->spilled_regs[i / BPF_REG_SIZE],
2685 &cur->spilled_regs[i / BPF_REG_SIZE],
2686 sizeof(old->spilled_regs[0])))
2687 /* when explored and current stack slot types are
2688 * the same, check that stored pointers types
2689 * are the same as well.
2690 * Ex: explored safe path could have stored
58e2af8b 2691 * (bpf_reg_state) {.type = PTR_TO_STACK, .imm = -8}
9c399760 2692 * but current path has stored:
58e2af8b 2693 * (bpf_reg_state) {.type = PTR_TO_STACK, .imm = -16}
9c399760
AS		 2694 * such verifier states are not equivalent.
2695 * return false to continue verification of this path
2696 */
2697 return false;
2698 else
2699 continue;
f1bca824
AS		 2700 }
2701 return true;
2702}
2703
58e2af8b 2704static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
f1bca824 2705{
58e2af8b
JK		 2706 struct bpf_verifier_state_list *new_sl;
2707 struct bpf_verifier_state_list *sl;
f1bca824
AS		 2708
2709 sl = env->explored_states[insn_idx];
2710 if (!sl)
2711 /* this 'insn_idx' instruction wasn't marked, so we will not
2712 * be doing state search here
2713 */
2714 return 0;
2715
2716 while (sl != STATE_LIST_MARK) {
48461135 2717 if (states_equal(env, &sl->state, &env->cur_state))
f1bca824
AS		 2718 /* reached equivalent register/stack state,
2719 * prune the search
2720 */
2721 return 1;
2722 sl = sl->next;
2723 }
2724
2725 /* there were no equivalent states, remember current one.
2726 * technically the current state is not proven to be safe yet,
2727 * but it will either reach bpf_exit (which means it's safe) or
2728 * it will be rejected. Since there are no loops, we won't be
2729 * seeing this 'insn_idx' instruction again on the way to bpf_exit
2730 */
58e2af8b 2731 new_sl = kmalloc(sizeof(struct bpf_verifier_state_list), GFP_USER);
f1bca824
AS		 2732 if (!new_sl)
2733 return -ENOMEM;
2734
2735 /* add new state to the head of linked list */
2736 memcpy(&new_sl->state, &env->cur_state, sizeof(env->cur_state));
2737 new_sl->next = env->explored_states[insn_idx];
2738 env->explored_states[insn_idx] = new_sl;
2739 return 0;
2740}
2741
13a27dfc
JK		 2742static int ext_analyzer_insn_hook(struct bpf_verifier_env *env,
2743 int insn_idx, int prev_insn_idx)
2744{
2745 if (!env->analyzer_ops || !env->analyzer_ops->insn_hook)
2746 return 0;
2747
2748 return env->analyzer_ops->insn_hook(env, insn_idx, prev_insn_idx);
2749}
2750
58e2af8b 2751static int do_check(struct bpf_verifier_env *env)
17a52670 2752{
58e2af8b 2753 struct bpf_verifier_state *state = &env->cur_state;
17a52670 2754 struct bpf_insn *insns = env->prog->insnsi;
58e2af8b 2755 struct bpf_reg_state *regs = state->regs;
17a52670
AS		 2756 int insn_cnt = env->prog->len;
2757 int insn_idx, prev_insn_idx = 0;
2758 int insn_processed = 0;
2759 bool do_print_state = false;
2760
2761 init_reg_state(regs);
2762 insn_idx = 0;
48461135 2763 env->varlen_map_value_access = false;
17a52670
AS		 2764 for (;;) {
2765 struct bpf_insn *insn;
2766 u8 class;
2767 int err;
2768
2769 if (insn_idx >= insn_cnt) {
2770 verbose("invalid insn idx %d insn_cnt %d\n",
2771 insn_idx, insn_cnt);
2772 return -EFAULT;
2773 }
2774
2775 insn = &insns[insn_idx];
2776 class = BPF_CLASS(insn->code);
2777
07016151 2778 if (++insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) {
bc1750f3 2779 verbose("BPF program is too large. Processed %d insn\n",
17a52670
AS		 2780 insn_processed);
2781 return -E2BIG;
2782 }
2783
f1bca824
AS		 2784 err = is_state_visited(env, insn_idx);
2785 if (err < 0)
2786 return err;
2787 if (err == 1) {
2788 /* found equivalent state, can prune the search */
2789 if (log_level) {
2790 if (do_print_state)
2791 verbose("\nfrom %d to %d: safe\n",
2792 prev_insn_idx, insn_idx);
2793 else
2794 verbose("%d: safe\n", insn_idx);
2795 }
2796 goto process_bpf_exit;
2797 }
2798
17a52670
AS		 2799 if (log_level && do_print_state) {
2800 verbose("\nfrom %d to %d:", prev_insn_idx, insn_idx);
1a0dc1ac 2801 print_verifier_state(&env->cur_state);
17a52670
AS		 2802 do_print_state = false;
2803 }
2804
2805 if (log_level) {
2806 verbose("%d: ", insn_idx);
2807 print_bpf_insn(insn);
2808 }
2809
13a27dfc
JK		 2810 err = ext_analyzer_insn_hook(env, insn_idx, prev_insn_idx);
2811 if (err)
2812 return err;
2813
17a52670 2814 if (class == BPF_ALU || class == BPF_ALU64) {
1be7f75d 2815 err = check_alu_op(env, insn);
17a52670
AS		 2816 if (err)
2817 return err;
2818
2819 } else if (class == BPF_LDX) {
3df126f3 2820 enum bpf_reg_type *prev_src_type, src_reg_type;
9bac3d6d
AS		 2821
2822 /* check for reserved fields is already done */
2823
17a52670
AS		 2824 /* check src operand */
2825 err = check_reg_arg(regs, insn->src_reg, SRC_OP);
2826 if (err)
2827 return err;
2828
2829 err = check_reg_arg(regs, insn->dst_reg, DST_OP_NO_MARK);
2830 if (err)
2831 return err;
2832
725f9dcd
AS		 2833 src_reg_type = regs[insn->src_reg].type;
2834
17a52670
AS		 2835 /* check that memory (src_reg + off) is readable,
2836 * the state of dst_reg will be updated by this func
2837 */
2838 err = check_mem_access(env, insn->src_reg, insn->off,
2839 BPF_SIZE(insn->code), BPF_READ,
2840 insn->dst_reg);
2841 if (err)
2842 return err;
2843
ea2e7ce5
AS		 2844 if (BPF_SIZE(insn->code) != BPF_W &&
2845 BPF_SIZE(insn->code) != BPF_DW) {
725f9dcd
AS		 2846 insn_idx++;
2847 continue;
2848 }
9bac3d6d 2849
3df126f3
JK		 2850 prev_src_type = &env->insn_aux_data[insn_idx].ptr_type;
2851
2852 if (*prev_src_type == NOT_INIT) {
9bac3d6d
AS		 2853 /* saw a valid insn
2854 * dst_reg = *(u32 *)(src_reg + off)
3df126f3 2855 * save type to validate intersecting paths
9bac3d6d 2856 */
3df126f3 2857 *prev_src_type = src_reg_type;
9bac3d6d 2858
3df126f3 2859 } else if (src_reg_type != *prev_src_type &&
9bac3d6d 2860 (src_reg_type == PTR_TO_CTX ||
3df126f3 2861 *prev_src_type == PTR_TO_CTX)) {
9bac3d6d
AS		 2862 /* ABuser program is trying to use the same insn
2863 * dst_reg = *(u32*) (src_reg + off)
2864 * with different pointer types:
2865 * src_reg == ctx in one branch and
2866 * src_reg == stack|map in some other branch.
2867 * Reject it.
2868 */
2869 verbose("same insn cannot be used with different pointers\n");
2870 return -EINVAL;
2871 }
2872
17a52670 2873 } else if (class == BPF_STX) {
3df126f3 2874 enum bpf_reg_type *prev_dst_type, dst_reg_type;
d691f9e8 2875
17a52670
AS		 2876 if (BPF_MODE(insn->code) == BPF_XADD) {
2877 err = check_xadd(env, insn);
2878 if (err)
2879 return err;
2880 insn_idx++;
2881 continue;
2882 }
2883
17a52670
AS		 2884 /* check src1 operand */
2885 err = check_reg_arg(regs, insn->src_reg, SRC_OP);
2886 if (err)
2887 return err;
2888 /* check src2 operand */
2889 err = check_reg_arg(regs, insn->dst_reg, SRC_OP);
2890 if (err)
2891 return err;
2892
d691f9e8
AS		 2893 dst_reg_type = regs[insn->dst_reg].type;
2894
17a52670
AS		 2895 /* check that memory (dst_reg + off) is writeable */
2896 err = check_mem_access(env, insn->dst_reg, insn->off,
2897 BPF_SIZE(insn->code), BPF_WRITE,
2898 insn->src_reg);
2899 if (err)
2900 return err;
2901
3df126f3
JK		 2902 prev_dst_type = &env->insn_aux_data[insn_idx].ptr_type;
2903
2904 if (*prev_dst_type == NOT_INIT) {
2905 *prev_dst_type = dst_reg_type;
2906 } else if (dst_reg_type != *prev_dst_type &&
d691f9e8 2907 (dst_reg_type == PTR_TO_CTX ||
3df126f3 2908 *prev_dst_type == PTR_TO_CTX)) {
d691f9e8
AS		 2909 verbose("same insn cannot be used with different pointers\n");
2910 return -EINVAL;
2911 }
2912
17a52670
AS		 2913 } else if (class == BPF_ST) {
2914 if (BPF_MODE(insn->code) != BPF_MEM ||
2915 insn->src_reg != BPF_REG_0) {
2916 verbose("BPF_ST uses reserved fields\n");
2917 return -EINVAL;
2918 }
2919 /* check src operand */
2920 err = check_reg_arg(regs, insn->dst_reg, SRC_OP);
2921 if (err)
2922 return err;
2923
2924 /* check that memory (dst_reg + off) is writeable */
2925 err = check_mem_access(env, insn->dst_reg, insn->off,
2926 BPF_SIZE(insn->code), BPF_WRITE,
2927 -1);
2928 if (err)
2929 return err;
2930
2931 } else if (class == BPF_JMP) {
2932 u8 opcode = BPF_OP(insn->code);
2933
2934 if (opcode == BPF_CALL) {
2935 if (BPF_SRC(insn->code) != BPF_K ||
2936 insn->off != 0 ||
2937 insn->src_reg != BPF_REG_0 ||
2938 insn->dst_reg != BPF_REG_0) {
2939 verbose("BPF_CALL uses reserved fields\n");
2940 return -EINVAL;
2941 }
2942
2943 err = check_call(env, insn->imm);
2944 if (err)
2945 return err;
2946
2947 } else if (opcode == BPF_JA) {
2948 if (BPF_SRC(insn->code) != BPF_K ||
2949 insn->imm != 0 ||
2950 insn->src_reg != BPF_REG_0 ||
2951 insn->dst_reg != BPF_REG_0) {
2952 verbose("BPF_JA uses reserved fields\n");
2953 return -EINVAL;
2954 }
2955
2956 insn_idx += insn->off + 1;
2957 continue;
2958
2959 } else if (opcode == BPF_EXIT) {
2960 if (BPF_SRC(insn->code) != BPF_K ||
2961 insn->imm != 0 ||
2962 insn->src_reg != BPF_REG_0 ||
2963 insn->dst_reg != BPF_REG_0) {
2964 verbose("BPF_EXIT uses reserved fields\n");
2965 return -EINVAL;
2966 }
2967
2968 /* eBPF calling convetion is such that R0 is used
2969 * to return the value from eBPF program.
2970 * Make sure that it's readable at this time
2971 * of bpf_exit, which means that program wrote
2972 * something into it earlier
2973 */
2974 err = check_reg_arg(regs, BPF_REG_0, SRC_OP);
2975 if (err)
2976 return err;
2977
1be7f75d
AS		 2978 if (is_pointer_value(env, BPF_REG_0)) {
2979 verbose("R0 leaks addr as return value\n");
2980 return -EACCES;
2981 }
2982
f1bca824 2983process_bpf_exit:
17a52670
AS		 2984 insn_idx = pop_stack(env, &prev_insn_idx);
2985 if (insn_idx < 0) {
2986 break;
2987 } else {
2988 do_print_state = true;
2989 continue;
2990 }
2991 } else {
2992 err = check_cond_jmp_op(env, insn, &insn_idx);
2993 if (err)
2994 return err;
2995 }
2996 } else if (class == BPF_LD) {
2997 u8 mode = BPF_MODE(insn->code);
2998
2999 if (mode == BPF_ABS || mode == BPF_IND) {
ddd872bc
AS		 3000 err = check_ld_abs(env, insn);
3001 if (err)
3002 return err;
3003
17a52670
AS		 3004 } else if (mode == BPF_IMM) {
3005 err = check_ld_imm(env, insn);
3006 if (err)
3007 return err;
3008
3009 insn_idx++;
3010 } else {
3011 verbose("invalid BPF_LD mode\n");
3012 return -EINVAL;
3013 }
48461135 3014 reset_reg_range_values(regs, insn->dst_reg);
17a52670
AS		 3015 } else {
3016 verbose("unknown insn class %d\n", class);
3017 return -EINVAL;
3018 }
3019
3020 insn_idx++;
3021 }
3022
1a0dc1ac 3023 verbose("processed %d insns\n", insn_processed);
17a52670
AS		 3024 return 0;
3025}
3026
fdc15d38
AS		 3027static int check_map_prog_compatibility(struct bpf_map *map,
3028 struct bpf_prog *prog)
3029
3030{
3031 if (prog->type == BPF_PROG_TYPE_PERF_EVENT &&
3032 (map->map_type == BPF_MAP_TYPE_HASH ||
3033 map->map_type == BPF_MAP_TYPE_PERCPU_HASH) &&
3034 (map->map_flags & BPF_F_NO_PREALLOC)) {
3035 verbose("perf_event programs can only use preallocated hash map\n");
3036 return -EINVAL;
3037 }
3038 return 0;
3039}
3040
0246e64d
AS		 3041/* look for pseudo eBPF instructions that access map FDs and
3042 * replace them with actual map pointers
3043 */
58e2af8b 3044static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env)
0246e64d
AS		 3045{
3046 struct bpf_insn *insn = env->prog->insnsi;
3047 int insn_cnt = env->prog->len;
fdc15d38 3048 int i, j, err;
0246e64d 3049
f1f7714e 3050 err = bpf_prog_calc_tag(env->prog);
aafe6ae9
DB		 3051 if (err)
3052 return err;
3053
0246e64d 3054 for (i = 0; i < insn_cnt; i++, insn++) {
9bac3d6d 3055 if (BPF_CLASS(insn->code) == BPF_LDX &&
d691f9e8 3056 (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0)) {
9bac3d6d
AS		 3057 verbose("BPF_LDX uses reserved fields\n");
3058 return -EINVAL;
3059 }
3060
d691f9e8
AS		 3061 if (BPF_CLASS(insn->code) == BPF_STX &&
3062 ((BPF_MODE(insn->code) != BPF_MEM &&
3063 BPF_MODE(insn->code) != BPF_XADD) || insn->imm != 0)) {
3064 verbose("BPF_STX uses reserved fields\n");
3065 return -EINVAL;
3066 }
3067
0246e64d
AS		 3068 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) {
3069 struct bpf_map *map;
3070 struct fd f;
3071
3072 if (i == insn_cnt - 1 || insn[1].code != 0 ||
3073 insn[1].dst_reg != 0 || insn[1].src_reg != 0 ||
3074 insn[1].off != 0) {
3075 verbose("invalid bpf_ld_imm64 insn\n");
3076 return -EINVAL;
3077 }
3078
3079 if (insn->src_reg == 0)
3080 /* valid generic load 64-bit imm */
3081 goto next_insn;
3082
3083 if (insn->src_reg != BPF_PSEUDO_MAP_FD) {
3084 verbose("unrecognized bpf_ld_imm64 insn\n");
3085 return -EINVAL;
3086 }
3087
3088 f = fdget(insn->imm);
c2101297 3089 map = __bpf_map_get(f);
0246e64d
AS		 3090 if (IS_ERR(map)) {
3091 verbose("fd %d is not pointing to valid bpf_map\n",
3092 insn->imm);
0246e64d
AS		 3093 return PTR_ERR(map);
3094 }
3095
fdc15d38
AS		 3096 err = check_map_prog_compatibility(map, env->prog);
3097 if (err) {
3098 fdput(f);
3099 return err;
3100 }
3101
0246e64d
AS		 3102 /* store map pointer inside BPF_LD_IMM64 instruction */
3103 insn[0].imm = (u32) (unsigned long) map;
3104 insn[1].imm = ((u64) (unsigned long) map) >> 32;
3105
3106 /* check whether we recorded this map already */
3107 for (j = 0; j < env->used_map_cnt; j++)
3108 if (env->used_maps[j] == map) {
3109 fdput(f);
3110 goto next_insn;
3111 }
3112
3113 if (env->used_map_cnt >= MAX_USED_MAPS) {
3114 fdput(f);
3115 return -E2BIG;
3116 }
3117
0246e64d
AS		 3118 /* hold the map. If the program is rejected by verifier,
3119 * the map will be released by release_maps() or it
3120 * will be used by the valid program until it's unloaded
3121 * and all maps are released in free_bpf_prog_info()
3122 */
92117d84
AS		 3123 map = bpf_map_inc(map, false);
3124 if (IS_ERR(map)) {
3125 fdput(f);
3126 return PTR_ERR(map);
3127 }
3128 env->used_maps[env->used_map_cnt++] = map;
3129
0246e64d
AS		 3130 fdput(f);
3131next_insn:
3132 insn++;
3133 i++;
3134 }
3135 }
3136
3137 /* now all pseudo BPF_LD_IMM64 instructions load valid
3138 * 'struct bpf_map *' into a register instead of user map_fd.
3139 * These pointers will be used later by verifier to validate map access.
3140 */
3141 return 0;
3142}
3143
3144/* drop refcnt of maps used by the rejected program */
58e2af8b 3145static void release_maps(struct bpf_verifier_env *env)
0246e64d
AS		 3146{
3147 int i;
3148
3149 for (i = 0; i < env->used_map_cnt; i++)
3150 bpf_map_put(env->used_maps[i]);
3151}
3152
3153/* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */
58e2af8b 3154static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env)
0246e64d
AS		 3155{
3156 struct bpf_insn *insn = env->prog->insnsi;
3157 int insn_cnt = env->prog->len;
3158 int i;
3159
3160 for (i = 0; i < insn_cnt; i++, insn++)
3161 if (insn->code == (BPF_LD | BPF_IMM | BPF_DW))
3162 insn->src_reg = 0;
3163}
3164
9bac3d6d
AS		 3165/* convert load instructions that access fields of 'struct __sk_buff'
3166 * into sequence of instructions that access fields of 'struct sk_buff'
3167 */
58e2af8b 3168static int convert_ctx_accesses(struct bpf_verifier_env *env)
9bac3d6d 3169{
36bbef52 3170 const struct bpf_verifier_ops *ops = env->prog->aux->ops;
3df126f3 3171 const int insn_cnt = env->prog->len;
36bbef52 3172 struct bpf_insn insn_buf[16], *insn;
9bac3d6d 3173 struct bpf_prog *new_prog;
d691f9e8 3174 enum bpf_access_type type;
3df126f3 3175 int i, cnt, delta = 0;
9bac3d6d 3176
36bbef52
DB		 3177 if (ops->gen_prologue) {
3178 cnt = ops->gen_prologue(insn_buf, env->seen_direct_write,
3179 env->prog);
3180 if (cnt >= ARRAY_SIZE(insn_buf)) {
3181 verbose("bpf verifier is misconfigured\n");
3182 return -EINVAL;
3183 } else if (cnt) {
3184 new_prog = bpf_patch_insn_single(env->prog, 0,
3185 insn_buf, cnt);
3186 if (!new_prog)
3187 return -ENOMEM;
3188 env->prog = new_prog;
3df126f3 3189 delta += cnt - 1;
36bbef52
DB		 3190 }
3191 }
3192
3193 if (!ops->convert_ctx_access)
9bac3d6d
AS		 3194 return 0;
3195
3df126f3 3196 insn = env->prog->insnsi + delta;
36bbef52 3197
9bac3d6d 3198 for (i = 0; i < insn_cnt; i++, insn++) {
62c7989b
DB		 3199 if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) ||
3200 insn->code == (BPF_LDX | BPF_MEM | BPF_H) ||
3201 insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
ea2e7ce5 3202 insn->code == (BPF_LDX | BPF_MEM | BPF_DW))
d691f9e8 3203 type = BPF_READ;
62c7989b
DB		 3204 else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) ||
3205 insn->code == (BPF_STX | BPF_MEM | BPF_H) ||
3206 insn->code == (BPF_STX | BPF_MEM | BPF_W) ||
ea2e7ce5 3207 insn->code == (BPF_STX | BPF_MEM | BPF_DW))
d691f9e8
AS		 3208 type = BPF_WRITE;
3209 else
9bac3d6d
AS		 3210 continue;
3211
3df126f3 3212 if (env->insn_aux_data[i].ptr_type != PTR_TO_CTX)
9bac3d6d 3213 continue;
9bac3d6d 3214
6b8cc1d1 3215 cnt = ops->convert_ctx_access(type, insn, insn_buf, env->prog);
9bac3d6d
AS		 3216 if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) {
3217 verbose("bpf verifier is misconfigured\n");
3218 return -EINVAL;
3219 }
3220
3df126f3
JK		 3221 new_prog = bpf_patch_insn_single(env->prog, i + delta, insn_buf,
3222 cnt);
9bac3d6d
AS		 3223 if (!new_prog)
3224 return -ENOMEM;
3225
3df126f3 3226 delta += cnt - 1;
9bac3d6d
AS		 3227
3228 /* keep walking new program and skip insns we just inserted */
3229 env->prog = new_prog;
3df126f3 3230 insn = new_prog->insnsi + i + delta;
9bac3d6d
AS		 3231 }
3232
3233 return 0;
3234}
3235
58e2af8b 3236static void free_states(struct bpf_verifier_env *env)
f1bca824 3237{
58e2af8b 3238 struct bpf_verifier_state_list *sl, *sln;
f1bca824
AS		 3239 int i;
3240
3241 if (!env->explored_states)
3242 return;
3243
3244 for (i = 0; i < env->prog->len; i++) {
3245 sl = env->explored_states[i];
3246
3247 if (sl)
3248 while (sl != STATE_LIST_MARK) {
3249 sln = sl->next;
3250 kfree(sl);
3251 sl = sln;
3252 }
3253 }
3254
3255 kfree(env->explored_states);
3256}
3257
9bac3d6d 3258int bpf_check(struct bpf_prog **prog, union bpf_attr *attr)
51580e79 3259{
cbd35700 3260 char __user *log_ubuf = NULL;
58e2af8b 3261 struct bpf_verifier_env *env;
51580e79
AS		 3262 int ret = -EINVAL;
3263
58e2af8b 3264 /* 'struct bpf_verifier_env' can be global, but since it's not small,
cbd35700
AS		 3265 * allocate/free it every time bpf_check() is called
3266 */
58e2af8b 3267 env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL);
cbd35700
AS		 3268 if (!env)
3269 return -ENOMEM;
3270
3df126f3
JK		 3271 env->insn_aux_data = vzalloc(sizeof(struct bpf_insn_aux_data) *
3272 (*prog)->len);
3273 ret = -ENOMEM;
3274 if (!env->insn_aux_data)
3275 goto err_free_env;
9bac3d6d 3276 env->prog = *prog;
0246e64d 3277
cbd35700
AS		 3278 /* grab the mutex to protect few globals used by verifier */
3279 mutex_lock(&bpf_verifier_lock);
3280
3281 if (attr->log_level || attr->log_buf || attr->log_size) {
3282 /* user requested verbose verifier output
3283 * and supplied buffer to store the verification trace
3284 */
3285 log_level = attr->log_level;
3286 log_ubuf = (char __user *) (unsigned long) attr->log_buf;
3287 log_size = attr->log_size;
3288 log_len = 0;
3289
3290 ret = -EINVAL;
3291 /* log_* values have to be sane */
3292 if (log_size < 128 || log_size > UINT_MAX >> 8 ||
3293 log_level == 0 || log_ubuf == NULL)
3df126f3 3294 goto err_unlock;
cbd35700
AS		 3295
3296 ret = -ENOMEM;
3297 log_buf = vmalloc(log_size);
3298 if (!log_buf)
3df126f3 3299 goto err_unlock;
cbd35700
AS		 3300 } else {
3301 log_level = 0;
3302 }
3303
0246e64d
AS		 3304 ret = replace_map_fd_with_map_ptr(env);
3305 if (ret < 0)
3306 goto skip_full_check;
3307
9bac3d6d 3308 env->explored_states = kcalloc(env->prog->len,
58e2af8b 3309 sizeof(struct bpf_verifier_state_list *),
f1bca824
AS		 3310 GFP_USER);
3311 ret = -ENOMEM;
3312 if (!env->explored_states)
3313 goto skip_full_check;
3314
475fb78f
AS		 3315 ret = check_cfg(env);
3316 if (ret < 0)
3317 goto skip_full_check;
3318
1be7f75d
AS		 3319 env->allow_ptr_leaks = capable(CAP_SYS_ADMIN);
3320
17a52670 3321 ret = do_check(env);
cbd35700 3322
0246e64d 3323skip_full_check:
17a52670 3324 while (pop_stack(env, NULL) >= 0);
f1bca824 3325 free_states(env);
0246e64d 3326
9bac3d6d
AS		 3327 if (ret == 0)
3328 /* program is valid, convert *(u32*)(ctx + off) accesses */
3329 ret = convert_ctx_accesses(env);
3330
cbd35700
AS		 3331 if (log_level && log_len >= log_size - 1) {
3332 BUG_ON(log_len >= log_size);
3333 /* verifier log exceeded user supplied buffer */
3334 ret = -ENOSPC;
3335 /* fall through to return what was recorded */
3336 }
3337
3338 /* copy verifier log back to user space including trailing zero */
3339 if (log_level && copy_to_user(log_ubuf, log_buf, log_len + 1) != 0) {
3340 ret = -EFAULT;
3341 goto free_log_buf;
3342 }
3343
0246e64d
AS		 3344 if (ret == 0 && env->used_map_cnt) {
3345 /* if program passed verifier, update used_maps in bpf_prog_info */
9bac3d6d
AS		 3346 env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt,
3347 sizeof(env->used_maps[0]),
3348 GFP_KERNEL);
0246e64d 3349
9bac3d6d 3350 if (!env->prog->aux->used_maps) {
0246e64d
AS		 3351 ret = -ENOMEM;
3352 goto free_log_buf;
3353 }
3354
9bac3d6d 3355 memcpy(env->prog->aux->used_maps, env->used_maps,
0246e64d 3356 sizeof(env->used_maps[0]) * env->used_map_cnt);
9bac3d6d 3357 env->prog->aux->used_map_cnt = env->used_map_cnt;
0246e64d
AS		 3358
3359 /* program is valid. Convert pseudo bpf_ld_imm64 into generic
3360 * bpf_ld_imm64 instructions
3361 */
3362 convert_pseudo_ld_imm64(env);
3363 }
cbd35700
AS		 3364
3365free_log_buf:
3366 if (log_level)
3367 vfree(log_buf);
9bac3d6d 3368 if (!env->prog->aux->used_maps)
0246e64d
AS		 3369 /* if we didn't copy map pointers into bpf_prog_info, release
3370 * them now. Otherwise free_bpf_prog_info() will release them.
3371 */
3372 release_maps(env);
9bac3d6d 3373 *prog = env->prog;
3df126f3 3374err_unlock:
cbd35700 3375 mutex_unlock(&bpf_verifier_lock);
3df126f3
JK		 3376 vfree(env->insn_aux_data);
3377err_free_env:
3378 kfree(env);
51580e79
AS		 3379 return ret;
3380}
13a27dfc
JK		 3381
3382int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops,
3383 void *priv)
3384{
3385 struct bpf_verifier_env *env;
3386 int ret;
3387
3388 env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL);
3389 if (!env)
3390 return -ENOMEM;
3391
3392 env->insn_aux_data = vzalloc(sizeof(struct bpf_insn_aux_data) *
3393 prog->len);
3394 ret = -ENOMEM;
3395 if (!env->insn_aux_data)
3396 goto err_free_env;
3397 env->prog = prog;
3398 env->analyzer_ops = ops;
3399 env->analyzer_priv = priv;
3400
3401 /* grab the mutex to protect few globals used by verifier */
3402 mutex_lock(&bpf_verifier_lock);
3403
3404 log_level = 0;
3405
3406 env->explored_states = kcalloc(env->prog->len,
3407 sizeof(struct bpf_verifier_state_list *),
3408 GFP_KERNEL);
3409 ret = -ENOMEM;
3410 if (!env->explored_states)
3411 goto skip_full_check;
3412
3413 ret = check_cfg(env);
3414 if (ret < 0)
3415 goto skip_full_check;
3416
3417 env->allow_ptr_leaks = capable(CAP_SYS_ADMIN);
3418
3419 ret = do_check(env);
3420
3421skip_full_check:
3422 while (pop_stack(env, NULL) >= 0);
3423 free_states(env);
3424
3425 mutex_unlock(&bpf_verifier_lock);
3426 vfree(env->insn_aux_data);
3427err_free_env:
3428 kfree(env);
3429 return ret;
3430}
3431EXPORT_SYMBOL_GPL(bpf_analyzer);
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