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