1 /* 2 * Linux Socket Filter - Kernel level socket filtering 3 * 4 * Based on the design of the Berkeley Packet Filter. The new 5 * internal format has been designed by PLUMgrid: 6 * 7 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com 8 * 9 * Authors: 10 * 11 * Jay Schulist <jschlst@samba.org> 12 * Alexei Starovoitov <ast@plumgrid.com> 13 * Daniel Borkmann <dborkman@redhat.com> 14 * 15 * This program is free software; you can redistribute it and/or 16 * modify it under the terms of the GNU General Public License 17 * as published by the Free Software Foundation; either version 18 * 2 of the License, or (at your option) any later version. 19 * 20 * Andi Kleen - Fix a few bad bugs and races. 21 * Kris Katterjohn - Added many additional checks in bpf_check_classic() 22 */ 23 24 #include <linux/filter.h> 25 #include <linux/skbuff.h> 26 #include <linux/vmalloc.h> 27 #include <linux/random.h> 28 #include <linux/moduleloader.h> 29 #include <linux/bpf.h> 30 #include <linux/frame.h> 31 32 #include <asm/unaligned.h> 33 34 /* Registers */ 35 #define BPF_R0 regs[BPF_REG_0] 36 #define BPF_R1 regs[BPF_REG_1] 37 #define BPF_R2 regs[BPF_REG_2] 38 #define BPF_R3 regs[BPF_REG_3] 39 #define BPF_R4 regs[BPF_REG_4] 40 #define BPF_R5 regs[BPF_REG_5] 41 #define BPF_R6 regs[BPF_REG_6] 42 #define BPF_R7 regs[BPF_REG_7] 43 #define BPF_R8 regs[BPF_REG_8] 44 #define BPF_R9 regs[BPF_REG_9] 45 #define BPF_R10 regs[BPF_REG_10] 46 47 /* Named registers */ 48 #define DST regs[insn->dst_reg] 49 #define SRC regs[insn->src_reg] 50 #define FP regs[BPF_REG_FP] 51 #define ARG1 regs[BPF_REG_ARG1] 52 #define CTX regs[BPF_REG_CTX] 53 #define IMM insn->imm 54 55 /* No hurry in this branch 56 * 57 * Exported for the bpf jit load helper. 58 */ 59 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 60 { 61 u8 *ptr = NULL; 62 63 if (k >= SKF_NET_OFF) 64 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 65 else if (k >= SKF_LL_OFF) 66 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 67 68 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 69 return ptr; 70 71 return NULL; 72 } 73 74 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 75 { 76 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO | 77 gfp_extra_flags; 78 struct bpf_prog_aux *aux; 79 struct bpf_prog *fp; 80 81 size = round_up(size, PAGE_SIZE); 82 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL); 83 if (fp == NULL) 84 return NULL; 85 86 kmemcheck_annotate_bitfield(fp, meta); 87 88 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags); 89 if (aux == NULL) { 90 vfree(fp); 91 return NULL; 92 } 93 94 fp->pages = size / PAGE_SIZE; 95 fp->aux = aux; 96 fp->aux->prog = fp; 97 98 return fp; 99 } 100 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 101 102 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 103 gfp_t gfp_extra_flags) 104 { 105 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO | 106 gfp_extra_flags; 107 struct bpf_prog *fp; 108 u32 pages, delta; 109 int ret; 110 111 BUG_ON(fp_old == NULL); 112 113 size = round_up(size, PAGE_SIZE); 114 pages = size / PAGE_SIZE; 115 if (pages <= fp_old->pages) 116 return fp_old; 117 118 delta = pages - fp_old->pages; 119 ret = __bpf_prog_charge(fp_old->aux->user, delta); 120 if (ret) 121 return NULL; 122 123 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL); 124 if (fp == NULL) { 125 __bpf_prog_uncharge(fp_old->aux->user, delta); 126 } else { 127 kmemcheck_annotate_bitfield(fp, meta); 128 129 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 130 fp->pages = pages; 131 fp->aux->prog = fp; 132 133 /* We keep fp->aux from fp_old around in the new 134 * reallocated structure. 135 */ 136 fp_old->aux = NULL; 137 __bpf_prog_free(fp_old); 138 } 139 140 return fp; 141 } 142 143 void __bpf_prog_free(struct bpf_prog *fp) 144 { 145 kfree(fp->aux); 146 vfree(fp); 147 } 148 149 int bpf_prog_calc_tag(struct bpf_prog *fp) 150 { 151 const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64); 152 u32 raw_size = bpf_prog_tag_scratch_size(fp); 153 u32 digest[SHA_DIGEST_WORDS]; 154 u32 ws[SHA_WORKSPACE_WORDS]; 155 u32 i, bsize, psize, blocks; 156 struct bpf_insn *dst; 157 bool was_ld_map; 158 u8 *raw, *todo; 159 __be32 *result; 160 __be64 *bits; 161 162 raw = vmalloc(raw_size); 163 if (!raw) 164 return -ENOMEM; 165 166 sha_init(digest); 167 memset(ws, 0, sizeof(ws)); 168 169 /* We need to take out the map fd for the digest calculation 170 * since they are unstable from user space side. 171 */ 172 dst = (void *)raw; 173 for (i = 0, was_ld_map = false; i < fp->len; i++) { 174 dst[i] = fp->insnsi[i]; 175 if (!was_ld_map && 176 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 177 dst[i].src_reg == BPF_PSEUDO_MAP_FD) { 178 was_ld_map = true; 179 dst[i].imm = 0; 180 } else if (was_ld_map && 181 dst[i].code == 0 && 182 dst[i].dst_reg == 0 && 183 dst[i].src_reg == 0 && 184 dst[i].off == 0) { 185 was_ld_map = false; 186 dst[i].imm = 0; 187 } else { 188 was_ld_map = false; 189 } 190 } 191 192 psize = bpf_prog_insn_size(fp); 193 memset(&raw[psize], 0, raw_size - psize); 194 raw[psize++] = 0x80; 195 196 bsize = round_up(psize, SHA_MESSAGE_BYTES); 197 blocks = bsize / SHA_MESSAGE_BYTES; 198 todo = raw; 199 if (bsize - psize >= sizeof(__be64)) { 200 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 201 } else { 202 bits = (__be64 *)(todo + bsize + bits_offset); 203 blocks++; 204 } 205 *bits = cpu_to_be64((psize - 1) << 3); 206 207 while (blocks--) { 208 sha_transform(digest, todo, ws); 209 todo += SHA_MESSAGE_BYTES; 210 } 211 212 result = (__force __be32 *)digest; 213 for (i = 0; i < SHA_DIGEST_WORDS; i++) 214 result[i] = cpu_to_be32(digest[i]); 215 memcpy(fp->tag, result, sizeof(fp->tag)); 216 217 vfree(raw); 218 return 0; 219 } 220 221 static bool bpf_is_jmp_and_has_target(const struct bpf_insn *insn) 222 { 223 return BPF_CLASS(insn->code) == BPF_JMP && 224 /* Call and Exit are both special jumps with no 225 * target inside the BPF instruction image. 226 */ 227 BPF_OP(insn->code) != BPF_CALL && 228 BPF_OP(insn->code) != BPF_EXIT; 229 } 230 231 static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta) 232 { 233 struct bpf_insn *insn = prog->insnsi; 234 u32 i, insn_cnt = prog->len; 235 236 for (i = 0; i < insn_cnt; i++, insn++) { 237 if (!bpf_is_jmp_and_has_target(insn)) 238 continue; 239 240 /* Adjust offset of jmps if we cross boundaries. */ 241 if (i < pos && i + insn->off + 1 > pos) 242 insn->off += delta; 243 else if (i > pos + delta && i + insn->off + 1 <= pos + delta) 244 insn->off -= delta; 245 } 246 } 247 248 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 249 const struct bpf_insn *patch, u32 len) 250 { 251 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 252 struct bpf_prog *prog_adj; 253 254 /* Since our patchlet doesn't expand the image, we're done. */ 255 if (insn_delta == 0) { 256 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 257 return prog; 258 } 259 260 insn_adj_cnt = prog->len + insn_delta; 261 262 /* Several new instructions need to be inserted. Make room 263 * for them. Likely, there's no need for a new allocation as 264 * last page could have large enough tailroom. 265 */ 266 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 267 GFP_USER); 268 if (!prog_adj) 269 return NULL; 270 271 prog_adj->len = insn_adj_cnt; 272 273 /* Patching happens in 3 steps: 274 * 275 * 1) Move over tail of insnsi from next instruction onwards, 276 * so we can patch the single target insn with one or more 277 * new ones (patching is always from 1 to n insns, n > 0). 278 * 2) Inject new instructions at the target location. 279 * 3) Adjust branch offsets if necessary. 280 */ 281 insn_rest = insn_adj_cnt - off - len; 282 283 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 284 sizeof(*patch) * insn_rest); 285 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 286 287 bpf_adj_branches(prog_adj, off, insn_delta); 288 289 return prog_adj; 290 } 291 292 #ifdef CONFIG_BPF_JIT 293 struct bpf_binary_header * 294 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 295 unsigned int alignment, 296 bpf_jit_fill_hole_t bpf_fill_ill_insns) 297 { 298 struct bpf_binary_header *hdr; 299 unsigned int size, hole, start; 300 301 /* Most of BPF filters are really small, but if some of them 302 * fill a page, allow at least 128 extra bytes to insert a 303 * random section of illegal instructions. 304 */ 305 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 306 hdr = module_alloc(size); 307 if (hdr == NULL) 308 return NULL; 309 310 /* Fill space with illegal/arch-dep instructions. */ 311 bpf_fill_ill_insns(hdr, size); 312 313 hdr->pages = size / PAGE_SIZE; 314 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 315 PAGE_SIZE - sizeof(*hdr)); 316 start = (get_random_int() % hole) & ~(alignment - 1); 317 318 /* Leave a random number of instructions before BPF code. */ 319 *image_ptr = &hdr->image[start]; 320 321 return hdr; 322 } 323 324 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 325 { 326 module_memfree(hdr); 327 } 328 329 int bpf_jit_harden __read_mostly; 330 331 static int bpf_jit_blind_insn(const struct bpf_insn *from, 332 const struct bpf_insn *aux, 333 struct bpf_insn *to_buff) 334 { 335 struct bpf_insn *to = to_buff; 336 u32 imm_rnd = get_random_int(); 337 s16 off; 338 339 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 340 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 341 342 if (from->imm == 0 && 343 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 344 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 345 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 346 goto out; 347 } 348 349 switch (from->code) { 350 case BPF_ALU | BPF_ADD | BPF_K: 351 case BPF_ALU | BPF_SUB | BPF_K: 352 case BPF_ALU | BPF_AND | BPF_K: 353 case BPF_ALU | BPF_OR | BPF_K: 354 case BPF_ALU | BPF_XOR | BPF_K: 355 case BPF_ALU | BPF_MUL | BPF_K: 356 case BPF_ALU | BPF_MOV | BPF_K: 357 case BPF_ALU | BPF_DIV | BPF_K: 358 case BPF_ALU | BPF_MOD | BPF_K: 359 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 360 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 361 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 362 break; 363 364 case BPF_ALU64 | BPF_ADD | BPF_K: 365 case BPF_ALU64 | BPF_SUB | BPF_K: 366 case BPF_ALU64 | BPF_AND | BPF_K: 367 case BPF_ALU64 | BPF_OR | BPF_K: 368 case BPF_ALU64 | BPF_XOR | BPF_K: 369 case BPF_ALU64 | BPF_MUL | BPF_K: 370 case BPF_ALU64 | BPF_MOV | BPF_K: 371 case BPF_ALU64 | BPF_DIV | BPF_K: 372 case BPF_ALU64 | BPF_MOD | BPF_K: 373 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 374 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 375 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 376 break; 377 378 case BPF_JMP | BPF_JEQ | BPF_K: 379 case BPF_JMP | BPF_JNE | BPF_K: 380 case BPF_JMP | BPF_JGT | BPF_K: 381 case BPF_JMP | BPF_JGE | BPF_K: 382 case BPF_JMP | BPF_JSGT | BPF_K: 383 case BPF_JMP | BPF_JSGE | BPF_K: 384 case BPF_JMP | BPF_JSET | BPF_K: 385 /* Accommodate for extra offset in case of a backjump. */ 386 off = from->off; 387 if (off < 0) 388 off -= 2; 389 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 390 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 391 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 392 break; 393 394 case BPF_LD | BPF_ABS | BPF_W: 395 case BPF_LD | BPF_ABS | BPF_H: 396 case BPF_LD | BPF_ABS | BPF_B: 397 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 398 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 399 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0); 400 break; 401 402 case BPF_LD | BPF_IND | BPF_W: 403 case BPF_LD | BPF_IND | BPF_H: 404 case BPF_LD | BPF_IND | BPF_B: 405 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 406 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 407 *to++ = BPF_ALU32_REG(BPF_ADD, BPF_REG_AX, from->src_reg); 408 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0); 409 break; 410 411 case BPF_LD | BPF_IMM | BPF_DW: 412 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 413 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 414 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 415 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 416 break; 417 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 418 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 419 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 420 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 421 break; 422 423 case BPF_ST | BPF_MEM | BPF_DW: 424 case BPF_ST | BPF_MEM | BPF_W: 425 case BPF_ST | BPF_MEM | BPF_H: 426 case BPF_ST | BPF_MEM | BPF_B: 427 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 428 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 429 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 430 break; 431 } 432 out: 433 return to - to_buff; 434 } 435 436 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 437 gfp_t gfp_extra_flags) 438 { 439 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO | 440 gfp_extra_flags; 441 struct bpf_prog *fp; 442 443 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL); 444 if (fp != NULL) { 445 kmemcheck_annotate_bitfield(fp, meta); 446 447 /* aux->prog still points to the fp_other one, so 448 * when promoting the clone to the real program, 449 * this still needs to be adapted. 450 */ 451 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 452 } 453 454 return fp; 455 } 456 457 static void bpf_prog_clone_free(struct bpf_prog *fp) 458 { 459 /* aux was stolen by the other clone, so we cannot free 460 * it from this path! It will be freed eventually by the 461 * other program on release. 462 * 463 * At this point, we don't need a deferred release since 464 * clone is guaranteed to not be locked. 465 */ 466 fp->aux = NULL; 467 __bpf_prog_free(fp); 468 } 469 470 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 471 { 472 /* We have to repoint aux->prog to self, as we don't 473 * know whether fp here is the clone or the original. 474 */ 475 fp->aux->prog = fp; 476 bpf_prog_clone_free(fp_other); 477 } 478 479 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 480 { 481 struct bpf_insn insn_buff[16], aux[2]; 482 struct bpf_prog *clone, *tmp; 483 int insn_delta, insn_cnt; 484 struct bpf_insn *insn; 485 int i, rewritten; 486 487 if (!bpf_jit_blinding_enabled()) 488 return prog; 489 490 clone = bpf_prog_clone_create(prog, GFP_USER); 491 if (!clone) 492 return ERR_PTR(-ENOMEM); 493 494 insn_cnt = clone->len; 495 insn = clone->insnsi; 496 497 for (i = 0; i < insn_cnt; i++, insn++) { 498 /* We temporarily need to hold the original ld64 insn 499 * so that we can still access the first part in the 500 * second blinding run. 501 */ 502 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 503 insn[1].code == 0) 504 memcpy(aux, insn, sizeof(aux)); 505 506 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff); 507 if (!rewritten) 508 continue; 509 510 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 511 if (!tmp) { 512 /* Patching may have repointed aux->prog during 513 * realloc from the original one, so we need to 514 * fix it up here on error. 515 */ 516 bpf_jit_prog_release_other(prog, clone); 517 return ERR_PTR(-ENOMEM); 518 } 519 520 clone = tmp; 521 insn_delta = rewritten - 1; 522 523 /* Walk new program and skip insns we just inserted. */ 524 insn = clone->insnsi + i + insn_delta; 525 insn_cnt += insn_delta; 526 i += insn_delta; 527 } 528 529 return clone; 530 } 531 #endif /* CONFIG_BPF_JIT */ 532 533 /* Base function for offset calculation. Needs to go into .text section, 534 * therefore keeping it non-static as well; will also be used by JITs 535 * anyway later on, so do not let the compiler omit it. 536 */ 537 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 538 { 539 return 0; 540 } 541 EXPORT_SYMBOL_GPL(__bpf_call_base); 542 543 /** 544 * __bpf_prog_run - run eBPF program on a given context 545 * @ctx: is the data we are operating on 546 * @insn: is the array of eBPF instructions 547 * 548 * Decode and execute eBPF instructions. 549 */ 550 static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn) 551 { 552 u64 stack[MAX_BPF_STACK / sizeof(u64)]; 553 u64 regs[MAX_BPF_REG], tmp; 554 static const void *jumptable[256] = { 555 [0 ... 255] = &&default_label, 556 /* Now overwrite non-defaults ... */ 557 /* 32 bit ALU operations */ 558 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X, 559 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K, 560 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X, 561 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K, 562 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X, 563 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K, 564 [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X, 565 [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K, 566 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X, 567 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K, 568 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X, 569 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K, 570 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X, 571 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K, 572 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X, 573 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K, 574 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X, 575 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K, 576 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X, 577 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K, 578 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X, 579 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K, 580 [BPF_ALU | BPF_NEG] = &&ALU_NEG, 581 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE, 582 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE, 583 /* 64 bit ALU operations */ 584 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X, 585 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K, 586 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X, 587 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K, 588 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X, 589 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K, 590 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X, 591 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K, 592 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X, 593 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K, 594 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X, 595 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K, 596 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X, 597 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K, 598 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X, 599 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K, 600 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X, 601 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K, 602 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X, 603 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K, 604 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X, 605 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K, 606 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X, 607 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K, 608 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG, 609 /* Call instruction */ 610 [BPF_JMP | BPF_CALL] = &&JMP_CALL, 611 [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL, 612 /* Jumps */ 613 [BPF_JMP | BPF_JA] = &&JMP_JA, 614 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X, 615 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K, 616 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X, 617 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K, 618 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X, 619 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K, 620 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X, 621 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K, 622 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X, 623 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K, 624 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X, 625 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K, 626 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X, 627 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K, 628 /* Program return */ 629 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT, 630 /* Store instructions */ 631 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B, 632 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H, 633 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W, 634 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW, 635 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W, 636 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW, 637 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B, 638 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H, 639 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W, 640 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW, 641 /* Load instructions */ 642 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B, 643 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H, 644 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W, 645 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW, 646 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W, 647 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H, 648 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B, 649 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W, 650 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H, 651 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B, 652 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW, 653 }; 654 u32 tail_call_cnt = 0; 655 void *ptr; 656 int off; 657 658 #define CONT ({ insn++; goto select_insn; }) 659 #define CONT_JMP ({ insn++; goto select_insn; }) 660 661 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; 662 ARG1 = (u64) (unsigned long) ctx; 663 664 select_insn: 665 goto *jumptable[insn->code]; 666 667 /* ALU */ 668 #define ALU(OPCODE, OP) \ 669 ALU64_##OPCODE##_X: \ 670 DST = DST OP SRC; \ 671 CONT; \ 672 ALU_##OPCODE##_X: \ 673 DST = (u32) DST OP (u32) SRC; \ 674 CONT; \ 675 ALU64_##OPCODE##_K: \ 676 DST = DST OP IMM; \ 677 CONT; \ 678 ALU_##OPCODE##_K: \ 679 DST = (u32) DST OP (u32) IMM; \ 680 CONT; 681 682 ALU(ADD, +) 683 ALU(SUB, -) 684 ALU(AND, &) 685 ALU(OR, |) 686 ALU(LSH, <<) 687 ALU(RSH, >>) 688 ALU(XOR, ^) 689 ALU(MUL, *) 690 #undef ALU 691 ALU_NEG: 692 DST = (u32) -DST; 693 CONT; 694 ALU64_NEG: 695 DST = -DST; 696 CONT; 697 ALU_MOV_X: 698 DST = (u32) SRC; 699 CONT; 700 ALU_MOV_K: 701 DST = (u32) IMM; 702 CONT; 703 ALU64_MOV_X: 704 DST = SRC; 705 CONT; 706 ALU64_MOV_K: 707 DST = IMM; 708 CONT; 709 LD_IMM_DW: 710 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 711 insn++; 712 CONT; 713 ALU64_ARSH_X: 714 (*(s64 *) &DST) >>= SRC; 715 CONT; 716 ALU64_ARSH_K: 717 (*(s64 *) &DST) >>= IMM; 718 CONT; 719 ALU64_MOD_X: 720 if (unlikely(SRC == 0)) 721 return 0; 722 div64_u64_rem(DST, SRC, &tmp); 723 DST = tmp; 724 CONT; 725 ALU_MOD_X: 726 if (unlikely(SRC == 0)) 727 return 0; 728 tmp = (u32) DST; 729 DST = do_div(tmp, (u32) SRC); 730 CONT; 731 ALU64_MOD_K: 732 div64_u64_rem(DST, IMM, &tmp); 733 DST = tmp; 734 CONT; 735 ALU_MOD_K: 736 tmp = (u32) DST; 737 DST = do_div(tmp, (u32) IMM); 738 CONT; 739 ALU64_DIV_X: 740 if (unlikely(SRC == 0)) 741 return 0; 742 DST = div64_u64(DST, SRC); 743 CONT; 744 ALU_DIV_X: 745 if (unlikely(SRC == 0)) 746 return 0; 747 tmp = (u32) DST; 748 do_div(tmp, (u32) SRC); 749 DST = (u32) tmp; 750 CONT; 751 ALU64_DIV_K: 752 DST = div64_u64(DST, IMM); 753 CONT; 754 ALU_DIV_K: 755 tmp = (u32) DST; 756 do_div(tmp, (u32) IMM); 757 DST = (u32) tmp; 758 CONT; 759 ALU_END_TO_BE: 760 switch (IMM) { 761 case 16: 762 DST = (__force u16) cpu_to_be16(DST); 763 break; 764 case 32: 765 DST = (__force u32) cpu_to_be32(DST); 766 break; 767 case 64: 768 DST = (__force u64) cpu_to_be64(DST); 769 break; 770 } 771 CONT; 772 ALU_END_TO_LE: 773 switch (IMM) { 774 case 16: 775 DST = (__force u16) cpu_to_le16(DST); 776 break; 777 case 32: 778 DST = (__force u32) cpu_to_le32(DST); 779 break; 780 case 64: 781 DST = (__force u64) cpu_to_le64(DST); 782 break; 783 } 784 CONT; 785 786 /* CALL */ 787 JMP_CALL: 788 /* Function call scratches BPF_R1-BPF_R5 registers, 789 * preserves BPF_R6-BPF_R9, and stores return value 790 * into BPF_R0. 791 */ 792 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 793 BPF_R4, BPF_R5); 794 CONT; 795 796 JMP_TAIL_CALL: { 797 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 798 struct bpf_array *array = container_of(map, struct bpf_array, map); 799 struct bpf_prog *prog; 800 u64 index = BPF_R3; 801 802 if (unlikely(index >= array->map.max_entries)) 803 goto out; 804 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) 805 goto out; 806 807 tail_call_cnt++; 808 809 prog = READ_ONCE(array->ptrs[index]); 810 if (!prog) 811 goto out; 812 813 /* ARG1 at this point is guaranteed to point to CTX from 814 * the verifier side due to the fact that the tail call is 815 * handeled like a helper, that is, bpf_tail_call_proto, 816 * where arg1_type is ARG_PTR_TO_CTX. 817 */ 818 insn = prog->insnsi; 819 goto select_insn; 820 out: 821 CONT; 822 } 823 /* JMP */ 824 JMP_JA: 825 insn += insn->off; 826 CONT; 827 JMP_JEQ_X: 828 if (DST == SRC) { 829 insn += insn->off; 830 CONT_JMP; 831 } 832 CONT; 833 JMP_JEQ_K: 834 if (DST == IMM) { 835 insn += insn->off; 836 CONT_JMP; 837 } 838 CONT; 839 JMP_JNE_X: 840 if (DST != SRC) { 841 insn += insn->off; 842 CONT_JMP; 843 } 844 CONT; 845 JMP_JNE_K: 846 if (DST != IMM) { 847 insn += insn->off; 848 CONT_JMP; 849 } 850 CONT; 851 JMP_JGT_X: 852 if (DST > SRC) { 853 insn += insn->off; 854 CONT_JMP; 855 } 856 CONT; 857 JMP_JGT_K: 858 if (DST > IMM) { 859 insn += insn->off; 860 CONT_JMP; 861 } 862 CONT; 863 JMP_JGE_X: 864 if (DST >= SRC) { 865 insn += insn->off; 866 CONT_JMP; 867 } 868 CONT; 869 JMP_JGE_K: 870 if (DST >= IMM) { 871 insn += insn->off; 872 CONT_JMP; 873 } 874 CONT; 875 JMP_JSGT_X: 876 if (((s64) DST) > ((s64) SRC)) { 877 insn += insn->off; 878 CONT_JMP; 879 } 880 CONT; 881 JMP_JSGT_K: 882 if (((s64) DST) > ((s64) IMM)) { 883 insn += insn->off; 884 CONT_JMP; 885 } 886 CONT; 887 JMP_JSGE_X: 888 if (((s64) DST) >= ((s64) SRC)) { 889 insn += insn->off; 890 CONT_JMP; 891 } 892 CONT; 893 JMP_JSGE_K: 894 if (((s64) DST) >= ((s64) IMM)) { 895 insn += insn->off; 896 CONT_JMP; 897 } 898 CONT; 899 JMP_JSET_X: 900 if (DST & SRC) { 901 insn += insn->off; 902 CONT_JMP; 903 } 904 CONT; 905 JMP_JSET_K: 906 if (DST & IMM) { 907 insn += insn->off; 908 CONT_JMP; 909 } 910 CONT; 911 JMP_EXIT: 912 return BPF_R0; 913 914 /* STX and ST and LDX*/ 915 #define LDST(SIZEOP, SIZE) \ 916 STX_MEM_##SIZEOP: \ 917 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 918 CONT; \ 919 ST_MEM_##SIZEOP: \ 920 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 921 CONT; \ 922 LDX_MEM_##SIZEOP: \ 923 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 924 CONT; 925 926 LDST(B, u8) 927 LDST(H, u16) 928 LDST(W, u32) 929 LDST(DW, u64) 930 #undef LDST 931 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */ 932 atomic_add((u32) SRC, (atomic_t *)(unsigned long) 933 (DST + insn->off)); 934 CONT; 935 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */ 936 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long) 937 (DST + insn->off)); 938 CONT; 939 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */ 940 off = IMM; 941 load_word: 942 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are 943 * only appearing in the programs where ctx == 944 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX] 945 * == BPF_R6, bpf_convert_filter() saves it in BPF_R6, 946 * internal BPF verifier will check that BPF_R6 == 947 * ctx. 948 * 949 * BPF_ABS and BPF_IND are wrappers of function calls, 950 * so they scratch BPF_R1-BPF_R5 registers, preserve 951 * BPF_R6-BPF_R9, and store return value into BPF_R0. 952 * 953 * Implicit input: 954 * ctx == skb == BPF_R6 == CTX 955 * 956 * Explicit input: 957 * SRC == any register 958 * IMM == 32-bit immediate 959 * 960 * Output: 961 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness 962 */ 963 964 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp); 965 if (likely(ptr != NULL)) { 966 BPF_R0 = get_unaligned_be32(ptr); 967 CONT; 968 } 969 970 return 0; 971 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */ 972 off = IMM; 973 load_half: 974 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp); 975 if (likely(ptr != NULL)) { 976 BPF_R0 = get_unaligned_be16(ptr); 977 CONT; 978 } 979 980 return 0; 981 LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */ 982 off = IMM; 983 load_byte: 984 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp); 985 if (likely(ptr != NULL)) { 986 BPF_R0 = *(u8 *)ptr; 987 CONT; 988 } 989 990 return 0; 991 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */ 992 off = IMM + SRC; 993 goto load_word; 994 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */ 995 off = IMM + SRC; 996 goto load_half; 997 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */ 998 off = IMM + SRC; 999 goto load_byte; 1000 1001 default_label: 1002 /* If we ever reach this, we have a bug somewhere. */ 1003 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code); 1004 return 0; 1005 } 1006 STACK_FRAME_NON_STANDARD(__bpf_prog_run); /* jump table */ 1007 1008 bool bpf_prog_array_compatible(struct bpf_array *array, 1009 const struct bpf_prog *fp) 1010 { 1011 if (!array->owner_prog_type) { 1012 /* There's no owner yet where we could check for 1013 * compatibility. 1014 */ 1015 array->owner_prog_type = fp->type; 1016 array->owner_jited = fp->jited; 1017 1018 return true; 1019 } 1020 1021 return array->owner_prog_type == fp->type && 1022 array->owner_jited == fp->jited; 1023 } 1024 1025 static int bpf_check_tail_call(const struct bpf_prog *fp) 1026 { 1027 struct bpf_prog_aux *aux = fp->aux; 1028 int i; 1029 1030 for (i = 0; i < aux->used_map_cnt; i++) { 1031 struct bpf_map *map = aux->used_maps[i]; 1032 struct bpf_array *array; 1033 1034 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) 1035 continue; 1036 1037 array = container_of(map, struct bpf_array, map); 1038 if (!bpf_prog_array_compatible(array, fp)) 1039 return -EINVAL; 1040 } 1041 1042 return 0; 1043 } 1044 1045 /** 1046 * bpf_prog_select_runtime - select exec runtime for BPF program 1047 * @fp: bpf_prog populated with internal BPF program 1048 * @err: pointer to error variable 1049 * 1050 * Try to JIT eBPF program, if JIT is not available, use interpreter. 1051 * The BPF program will be executed via BPF_PROG_RUN() macro. 1052 */ 1053 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 1054 { 1055 fp->bpf_func = (void *) __bpf_prog_run; 1056 1057 /* eBPF JITs can rewrite the program in case constant 1058 * blinding is active. However, in case of error during 1059 * blinding, bpf_int_jit_compile() must always return a 1060 * valid program, which in this case would simply not 1061 * be JITed, but falls back to the interpreter. 1062 */ 1063 fp = bpf_int_jit_compile(fp); 1064 bpf_prog_lock_ro(fp); 1065 1066 /* The tail call compatibility check can only be done at 1067 * this late stage as we need to determine, if we deal 1068 * with JITed or non JITed program concatenations and not 1069 * all eBPF JITs might immediately support all features. 1070 */ 1071 *err = bpf_check_tail_call(fp); 1072 1073 return fp; 1074 } 1075 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 1076 1077 static void bpf_prog_free_deferred(struct work_struct *work) 1078 { 1079 struct bpf_prog_aux *aux; 1080 1081 aux = container_of(work, struct bpf_prog_aux, work); 1082 bpf_jit_free(aux->prog); 1083 } 1084 1085 /* Free internal BPF program */ 1086 void bpf_prog_free(struct bpf_prog *fp) 1087 { 1088 struct bpf_prog_aux *aux = fp->aux; 1089 1090 INIT_WORK(&aux->work, bpf_prog_free_deferred); 1091 schedule_work(&aux->work); 1092 } 1093 EXPORT_SYMBOL_GPL(bpf_prog_free); 1094 1095 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 1096 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 1097 1098 void bpf_user_rnd_init_once(void) 1099 { 1100 prandom_init_once(&bpf_user_rnd_state); 1101 } 1102 1103 BPF_CALL_0(bpf_user_rnd_u32) 1104 { 1105 /* Should someone ever have the rather unwise idea to use some 1106 * of the registers passed into this function, then note that 1107 * this function is called from native eBPF and classic-to-eBPF 1108 * transformations. Register assignments from both sides are 1109 * different, f.e. classic always sets fn(ctx, A, X) here. 1110 */ 1111 struct rnd_state *state; 1112 u32 res; 1113 1114 state = &get_cpu_var(bpf_user_rnd_state); 1115 res = prandom_u32_state(state); 1116 put_cpu_var(bpf_user_rnd_state); 1117 1118 return res; 1119 } 1120 1121 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 1122 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 1123 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 1124 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 1125 1126 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 1127 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 1128 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 1129 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 1130 1131 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 1132 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 1133 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 1134 1135 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 1136 { 1137 return NULL; 1138 } 1139 1140 u64 __weak 1141 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 1142 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 1143 { 1144 return -ENOTSUPP; 1145 } 1146 1147 /* Always built-in helper functions. */ 1148 const struct bpf_func_proto bpf_tail_call_proto = { 1149 .func = NULL, 1150 .gpl_only = false, 1151 .ret_type = RET_VOID, 1152 .arg1_type = ARG_PTR_TO_CTX, 1153 .arg2_type = ARG_CONST_MAP_PTR, 1154 .arg3_type = ARG_ANYTHING, 1155 }; 1156 1157 /* For classic BPF JITs that don't implement bpf_int_jit_compile(). */ 1158 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 1159 { 1160 return prog; 1161 } 1162 1163 bool __weak bpf_helper_changes_pkt_data(void *func) 1164 { 1165 return false; 1166 } 1167 1168 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 1169 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 1170 */ 1171 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 1172 int len) 1173 { 1174 return -EFAULT; 1175 } 1176