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 #include <linux/rbtree_latch.h> 32 #include <linux/kallsyms.h> 33 #include <linux/rcupdate.h> 34 35 #include <asm/unaligned.h> 36 37 /* Registers */ 38 #define BPF_R0 regs[BPF_REG_0] 39 #define BPF_R1 regs[BPF_REG_1] 40 #define BPF_R2 regs[BPF_REG_2] 41 #define BPF_R3 regs[BPF_REG_3] 42 #define BPF_R4 regs[BPF_REG_4] 43 #define BPF_R5 regs[BPF_REG_5] 44 #define BPF_R6 regs[BPF_REG_6] 45 #define BPF_R7 regs[BPF_REG_7] 46 #define BPF_R8 regs[BPF_REG_8] 47 #define BPF_R9 regs[BPF_REG_9] 48 #define BPF_R10 regs[BPF_REG_10] 49 50 /* Named registers */ 51 #define DST regs[insn->dst_reg] 52 #define SRC regs[insn->src_reg] 53 #define FP regs[BPF_REG_FP] 54 #define ARG1 regs[BPF_REG_ARG1] 55 #define CTX regs[BPF_REG_CTX] 56 #define IMM insn->imm 57 58 /* No hurry in this branch 59 * 60 * Exported for the bpf jit load helper. 61 */ 62 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 63 { 64 u8 *ptr = NULL; 65 66 if (k >= SKF_NET_OFF) 67 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 68 else if (k >= SKF_LL_OFF) 69 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 70 71 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 72 return ptr; 73 74 return NULL; 75 } 76 77 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 78 { 79 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO | 80 gfp_extra_flags; 81 struct bpf_prog_aux *aux; 82 struct bpf_prog *fp; 83 84 size = round_up(size, PAGE_SIZE); 85 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL); 86 if (fp == NULL) 87 return NULL; 88 89 kmemcheck_annotate_bitfield(fp, meta); 90 91 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags); 92 if (aux == NULL) { 93 vfree(fp); 94 return NULL; 95 } 96 97 fp->pages = size / PAGE_SIZE; 98 fp->aux = aux; 99 fp->aux->prog = fp; 100 101 INIT_LIST_HEAD_RCU(&fp->aux->ksym_lnode); 102 103 return fp; 104 } 105 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 106 107 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 108 gfp_t gfp_extra_flags) 109 { 110 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO | 111 gfp_extra_flags; 112 struct bpf_prog *fp; 113 u32 pages, delta; 114 int ret; 115 116 BUG_ON(fp_old == NULL); 117 118 size = round_up(size, PAGE_SIZE); 119 pages = size / PAGE_SIZE; 120 if (pages <= fp_old->pages) 121 return fp_old; 122 123 delta = pages - fp_old->pages; 124 ret = __bpf_prog_charge(fp_old->aux->user, delta); 125 if (ret) 126 return NULL; 127 128 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL); 129 if (fp == NULL) { 130 __bpf_prog_uncharge(fp_old->aux->user, delta); 131 } else { 132 kmemcheck_annotate_bitfield(fp, meta); 133 134 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 135 fp->pages = pages; 136 fp->aux->prog = fp; 137 138 /* We keep fp->aux from fp_old around in the new 139 * reallocated structure. 140 */ 141 fp_old->aux = NULL; 142 __bpf_prog_free(fp_old); 143 } 144 145 return fp; 146 } 147 148 void __bpf_prog_free(struct bpf_prog *fp) 149 { 150 kfree(fp->aux); 151 vfree(fp); 152 } 153 154 int bpf_prog_calc_tag(struct bpf_prog *fp) 155 { 156 const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64); 157 u32 raw_size = bpf_prog_tag_scratch_size(fp); 158 u32 digest[SHA_DIGEST_WORDS]; 159 u32 ws[SHA_WORKSPACE_WORDS]; 160 u32 i, bsize, psize, blocks; 161 struct bpf_insn *dst; 162 bool was_ld_map; 163 u8 *raw, *todo; 164 __be32 *result; 165 __be64 *bits; 166 167 raw = vmalloc(raw_size); 168 if (!raw) 169 return -ENOMEM; 170 171 sha_init(digest); 172 memset(ws, 0, sizeof(ws)); 173 174 /* We need to take out the map fd for the digest calculation 175 * since they are unstable from user space side. 176 */ 177 dst = (void *)raw; 178 for (i = 0, was_ld_map = false; i < fp->len; i++) { 179 dst[i] = fp->insnsi[i]; 180 if (!was_ld_map && 181 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 182 dst[i].src_reg == BPF_PSEUDO_MAP_FD) { 183 was_ld_map = true; 184 dst[i].imm = 0; 185 } else if (was_ld_map && 186 dst[i].code == 0 && 187 dst[i].dst_reg == 0 && 188 dst[i].src_reg == 0 && 189 dst[i].off == 0) { 190 was_ld_map = false; 191 dst[i].imm = 0; 192 } else { 193 was_ld_map = false; 194 } 195 } 196 197 psize = bpf_prog_insn_size(fp); 198 memset(&raw[psize], 0, raw_size - psize); 199 raw[psize++] = 0x80; 200 201 bsize = round_up(psize, SHA_MESSAGE_BYTES); 202 blocks = bsize / SHA_MESSAGE_BYTES; 203 todo = raw; 204 if (bsize - psize >= sizeof(__be64)) { 205 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 206 } else { 207 bits = (__be64 *)(todo + bsize + bits_offset); 208 blocks++; 209 } 210 *bits = cpu_to_be64((psize - 1) << 3); 211 212 while (blocks--) { 213 sha_transform(digest, todo, ws); 214 todo += SHA_MESSAGE_BYTES; 215 } 216 217 result = (__force __be32 *)digest; 218 for (i = 0; i < SHA_DIGEST_WORDS; i++) 219 result[i] = cpu_to_be32(digest[i]); 220 memcpy(fp->tag, result, sizeof(fp->tag)); 221 222 vfree(raw); 223 return 0; 224 } 225 226 static bool bpf_is_jmp_and_has_target(const struct bpf_insn *insn) 227 { 228 return BPF_CLASS(insn->code) == BPF_JMP && 229 /* Call and Exit are both special jumps with no 230 * target inside the BPF instruction image. 231 */ 232 BPF_OP(insn->code) != BPF_CALL && 233 BPF_OP(insn->code) != BPF_EXIT; 234 } 235 236 static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta) 237 { 238 struct bpf_insn *insn = prog->insnsi; 239 u32 i, insn_cnt = prog->len; 240 241 for (i = 0; i < insn_cnt; i++, insn++) { 242 if (!bpf_is_jmp_and_has_target(insn)) 243 continue; 244 245 /* Adjust offset of jmps if we cross boundaries. */ 246 if (i < pos && i + insn->off + 1 > pos) 247 insn->off += delta; 248 else if (i > pos + delta && i + insn->off + 1 <= pos + delta) 249 insn->off -= delta; 250 } 251 } 252 253 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 254 const struct bpf_insn *patch, u32 len) 255 { 256 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 257 struct bpf_prog *prog_adj; 258 259 /* Since our patchlet doesn't expand the image, we're done. */ 260 if (insn_delta == 0) { 261 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 262 return prog; 263 } 264 265 insn_adj_cnt = prog->len + insn_delta; 266 267 /* Several new instructions need to be inserted. Make room 268 * for them. Likely, there's no need for a new allocation as 269 * last page could have large enough tailroom. 270 */ 271 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 272 GFP_USER); 273 if (!prog_adj) 274 return NULL; 275 276 prog_adj->len = insn_adj_cnt; 277 278 /* Patching happens in 3 steps: 279 * 280 * 1) Move over tail of insnsi from next instruction onwards, 281 * so we can patch the single target insn with one or more 282 * new ones (patching is always from 1 to n insns, n > 0). 283 * 2) Inject new instructions at the target location. 284 * 3) Adjust branch offsets if necessary. 285 */ 286 insn_rest = insn_adj_cnt - off - len; 287 288 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 289 sizeof(*patch) * insn_rest); 290 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 291 292 bpf_adj_branches(prog_adj, off, insn_delta); 293 294 return prog_adj; 295 } 296 297 #ifdef CONFIG_BPF_JIT 298 static __always_inline void 299 bpf_get_prog_addr_region(const struct bpf_prog *prog, 300 unsigned long *symbol_start, 301 unsigned long *symbol_end) 302 { 303 const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog); 304 unsigned long addr = (unsigned long)hdr; 305 306 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 307 308 *symbol_start = addr; 309 *symbol_end = addr + hdr->pages * PAGE_SIZE; 310 } 311 312 static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym) 313 { 314 BUILD_BUG_ON(sizeof("bpf_prog_") + 315 sizeof(prog->tag) * 2 + 1 > KSYM_NAME_LEN); 316 317 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 318 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 319 *sym = 0; 320 } 321 322 static __always_inline unsigned long 323 bpf_get_prog_addr_start(struct latch_tree_node *n) 324 { 325 unsigned long symbol_start, symbol_end; 326 const struct bpf_prog_aux *aux; 327 328 aux = container_of(n, struct bpf_prog_aux, ksym_tnode); 329 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end); 330 331 return symbol_start; 332 } 333 334 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 335 struct latch_tree_node *b) 336 { 337 return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b); 338 } 339 340 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 341 { 342 unsigned long val = (unsigned long)key; 343 unsigned long symbol_start, symbol_end; 344 const struct bpf_prog_aux *aux; 345 346 aux = container_of(n, struct bpf_prog_aux, ksym_tnode); 347 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end); 348 349 if (val < symbol_start) 350 return -1; 351 if (val >= symbol_end) 352 return 1; 353 354 return 0; 355 } 356 357 static const struct latch_tree_ops bpf_tree_ops = { 358 .less = bpf_tree_less, 359 .comp = bpf_tree_comp, 360 }; 361 362 static DEFINE_SPINLOCK(bpf_lock); 363 static LIST_HEAD(bpf_kallsyms); 364 static struct latch_tree_root bpf_tree __cacheline_aligned; 365 366 int bpf_jit_kallsyms __read_mostly; 367 368 static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux) 369 { 370 WARN_ON_ONCE(!list_empty(&aux->ksym_lnode)); 371 list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms); 372 latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); 373 } 374 375 static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux) 376 { 377 if (list_empty(&aux->ksym_lnode)) 378 return; 379 380 latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); 381 list_del_rcu(&aux->ksym_lnode); 382 } 383 384 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 385 { 386 return fp->jited && !bpf_prog_was_classic(fp); 387 } 388 389 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp) 390 { 391 return list_empty(&fp->aux->ksym_lnode) || 392 fp->aux->ksym_lnode.prev == LIST_POISON2; 393 } 394 395 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 396 { 397 unsigned long flags; 398 399 if (!bpf_prog_kallsyms_candidate(fp) || 400 !capable(CAP_SYS_ADMIN)) 401 return; 402 403 spin_lock_irqsave(&bpf_lock, flags); 404 bpf_prog_ksym_node_add(fp->aux); 405 spin_unlock_irqrestore(&bpf_lock, flags); 406 } 407 408 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 409 { 410 unsigned long flags; 411 412 if (!bpf_prog_kallsyms_candidate(fp)) 413 return; 414 415 spin_lock_irqsave(&bpf_lock, flags); 416 bpf_prog_ksym_node_del(fp->aux); 417 spin_unlock_irqrestore(&bpf_lock, flags); 418 } 419 420 static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr) 421 { 422 struct latch_tree_node *n; 423 424 if (!bpf_jit_kallsyms_enabled()) 425 return NULL; 426 427 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 428 return n ? 429 container_of(n, struct bpf_prog_aux, ksym_tnode)->prog : 430 NULL; 431 } 432 433 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, 434 unsigned long *off, char *sym) 435 { 436 unsigned long symbol_start, symbol_end; 437 struct bpf_prog *prog; 438 char *ret = NULL; 439 440 rcu_read_lock(); 441 prog = bpf_prog_kallsyms_find(addr); 442 if (prog) { 443 bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end); 444 bpf_get_prog_name(prog, sym); 445 446 ret = sym; 447 if (size) 448 *size = symbol_end - symbol_start; 449 if (off) 450 *off = addr - symbol_start; 451 } 452 rcu_read_unlock(); 453 454 return ret; 455 } 456 457 bool is_bpf_text_address(unsigned long addr) 458 { 459 bool ret; 460 461 rcu_read_lock(); 462 ret = bpf_prog_kallsyms_find(addr) != NULL; 463 rcu_read_unlock(); 464 465 return ret; 466 } 467 468 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 469 char *sym) 470 { 471 unsigned long symbol_start, symbol_end; 472 struct bpf_prog_aux *aux; 473 unsigned int it = 0; 474 int ret = -ERANGE; 475 476 if (!bpf_jit_kallsyms_enabled()) 477 return ret; 478 479 rcu_read_lock(); 480 list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) { 481 if (it++ != symnum) 482 continue; 483 484 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end); 485 bpf_get_prog_name(aux->prog, sym); 486 487 *value = symbol_start; 488 *type = BPF_SYM_ELF_TYPE; 489 490 ret = 0; 491 break; 492 } 493 rcu_read_unlock(); 494 495 return ret; 496 } 497 498 struct bpf_binary_header * 499 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 500 unsigned int alignment, 501 bpf_jit_fill_hole_t bpf_fill_ill_insns) 502 { 503 struct bpf_binary_header *hdr; 504 unsigned int size, hole, start; 505 506 /* Most of BPF filters are really small, but if some of them 507 * fill a page, allow at least 128 extra bytes to insert a 508 * random section of illegal instructions. 509 */ 510 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 511 hdr = module_alloc(size); 512 if (hdr == NULL) 513 return NULL; 514 515 /* Fill space with illegal/arch-dep instructions. */ 516 bpf_fill_ill_insns(hdr, size); 517 518 hdr->pages = size / PAGE_SIZE; 519 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 520 PAGE_SIZE - sizeof(*hdr)); 521 start = (get_random_int() % hole) & ~(alignment - 1); 522 523 /* Leave a random number of instructions before BPF code. */ 524 *image_ptr = &hdr->image[start]; 525 526 return hdr; 527 } 528 529 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 530 { 531 module_memfree(hdr); 532 } 533 534 /* This symbol is only overridden by archs that have different 535 * requirements than the usual eBPF JITs, f.e. when they only 536 * implement cBPF JIT, do not set images read-only, etc. 537 */ 538 void __weak bpf_jit_free(struct bpf_prog *fp) 539 { 540 if (fp->jited) { 541 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 542 543 bpf_jit_binary_unlock_ro(hdr); 544 bpf_jit_binary_free(hdr); 545 546 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 547 } 548 549 bpf_prog_unlock_free(fp); 550 } 551 552 int bpf_jit_harden __read_mostly; 553 554 static int bpf_jit_blind_insn(const struct bpf_insn *from, 555 const struct bpf_insn *aux, 556 struct bpf_insn *to_buff) 557 { 558 struct bpf_insn *to = to_buff; 559 u32 imm_rnd = get_random_int(); 560 s16 off; 561 562 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 563 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 564 565 if (from->imm == 0 && 566 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 567 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 568 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 569 goto out; 570 } 571 572 switch (from->code) { 573 case BPF_ALU | BPF_ADD | BPF_K: 574 case BPF_ALU | BPF_SUB | BPF_K: 575 case BPF_ALU | BPF_AND | BPF_K: 576 case BPF_ALU | BPF_OR | BPF_K: 577 case BPF_ALU | BPF_XOR | BPF_K: 578 case BPF_ALU | BPF_MUL | BPF_K: 579 case BPF_ALU | BPF_MOV | BPF_K: 580 case BPF_ALU | BPF_DIV | BPF_K: 581 case BPF_ALU | BPF_MOD | BPF_K: 582 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 583 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 584 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 585 break; 586 587 case BPF_ALU64 | BPF_ADD | BPF_K: 588 case BPF_ALU64 | BPF_SUB | BPF_K: 589 case BPF_ALU64 | BPF_AND | BPF_K: 590 case BPF_ALU64 | BPF_OR | BPF_K: 591 case BPF_ALU64 | BPF_XOR | BPF_K: 592 case BPF_ALU64 | BPF_MUL | BPF_K: 593 case BPF_ALU64 | BPF_MOV | BPF_K: 594 case BPF_ALU64 | BPF_DIV | BPF_K: 595 case BPF_ALU64 | BPF_MOD | BPF_K: 596 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 597 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 598 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 599 break; 600 601 case BPF_JMP | BPF_JEQ | BPF_K: 602 case BPF_JMP | BPF_JNE | BPF_K: 603 case BPF_JMP | BPF_JGT | BPF_K: 604 case BPF_JMP | BPF_JGE | BPF_K: 605 case BPF_JMP | BPF_JSGT | BPF_K: 606 case BPF_JMP | BPF_JSGE | BPF_K: 607 case BPF_JMP | BPF_JSET | BPF_K: 608 /* Accommodate for extra offset in case of a backjump. */ 609 off = from->off; 610 if (off < 0) 611 off -= 2; 612 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 613 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 614 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 615 break; 616 617 case BPF_LD | BPF_ABS | BPF_W: 618 case BPF_LD | BPF_ABS | BPF_H: 619 case BPF_LD | BPF_ABS | BPF_B: 620 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 621 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 622 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0); 623 break; 624 625 case BPF_LD | BPF_IND | BPF_W: 626 case BPF_LD | BPF_IND | BPF_H: 627 case BPF_LD | BPF_IND | BPF_B: 628 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 629 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 630 *to++ = BPF_ALU32_REG(BPF_ADD, BPF_REG_AX, from->src_reg); 631 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0); 632 break; 633 634 case BPF_LD | BPF_IMM | BPF_DW: 635 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 636 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 637 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 638 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 639 break; 640 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 641 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 642 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 643 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 644 break; 645 646 case BPF_ST | BPF_MEM | BPF_DW: 647 case BPF_ST | BPF_MEM | BPF_W: 648 case BPF_ST | BPF_MEM | BPF_H: 649 case BPF_ST | BPF_MEM | BPF_B: 650 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 651 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 652 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 653 break; 654 } 655 out: 656 return to - to_buff; 657 } 658 659 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 660 gfp_t gfp_extra_flags) 661 { 662 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO | 663 gfp_extra_flags; 664 struct bpf_prog *fp; 665 666 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL); 667 if (fp != NULL) { 668 kmemcheck_annotate_bitfield(fp, meta); 669 670 /* aux->prog still points to the fp_other one, so 671 * when promoting the clone to the real program, 672 * this still needs to be adapted. 673 */ 674 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 675 } 676 677 return fp; 678 } 679 680 static void bpf_prog_clone_free(struct bpf_prog *fp) 681 { 682 /* aux was stolen by the other clone, so we cannot free 683 * it from this path! It will be freed eventually by the 684 * other program on release. 685 * 686 * At this point, we don't need a deferred release since 687 * clone is guaranteed to not be locked. 688 */ 689 fp->aux = NULL; 690 __bpf_prog_free(fp); 691 } 692 693 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 694 { 695 /* We have to repoint aux->prog to self, as we don't 696 * know whether fp here is the clone or the original. 697 */ 698 fp->aux->prog = fp; 699 bpf_prog_clone_free(fp_other); 700 } 701 702 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 703 { 704 struct bpf_insn insn_buff[16], aux[2]; 705 struct bpf_prog *clone, *tmp; 706 int insn_delta, insn_cnt; 707 struct bpf_insn *insn; 708 int i, rewritten; 709 710 if (!bpf_jit_blinding_enabled()) 711 return prog; 712 713 clone = bpf_prog_clone_create(prog, GFP_USER); 714 if (!clone) 715 return ERR_PTR(-ENOMEM); 716 717 insn_cnt = clone->len; 718 insn = clone->insnsi; 719 720 for (i = 0; i < insn_cnt; i++, insn++) { 721 /* We temporarily need to hold the original ld64 insn 722 * so that we can still access the first part in the 723 * second blinding run. 724 */ 725 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 726 insn[1].code == 0) 727 memcpy(aux, insn, sizeof(aux)); 728 729 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff); 730 if (!rewritten) 731 continue; 732 733 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 734 if (!tmp) { 735 /* Patching may have repointed aux->prog during 736 * realloc from the original one, so we need to 737 * fix it up here on error. 738 */ 739 bpf_jit_prog_release_other(prog, clone); 740 return ERR_PTR(-ENOMEM); 741 } 742 743 clone = tmp; 744 insn_delta = rewritten - 1; 745 746 /* Walk new program and skip insns we just inserted. */ 747 insn = clone->insnsi + i + insn_delta; 748 insn_cnt += insn_delta; 749 i += insn_delta; 750 } 751 752 return clone; 753 } 754 #endif /* CONFIG_BPF_JIT */ 755 756 /* Base function for offset calculation. Needs to go into .text section, 757 * therefore keeping it non-static as well; will also be used by JITs 758 * anyway later on, so do not let the compiler omit it. 759 */ 760 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 761 { 762 return 0; 763 } 764 EXPORT_SYMBOL_GPL(__bpf_call_base); 765 766 /** 767 * __bpf_prog_run - run eBPF program on a given context 768 * @ctx: is the data we are operating on 769 * @insn: is the array of eBPF instructions 770 * 771 * Decode and execute eBPF instructions. 772 */ 773 static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn) 774 { 775 u64 stack[MAX_BPF_STACK / sizeof(u64)]; 776 u64 regs[MAX_BPF_REG], tmp; 777 static const void *jumptable[256] = { 778 [0 ... 255] = &&default_label, 779 /* Now overwrite non-defaults ... */ 780 /* 32 bit ALU operations */ 781 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X, 782 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K, 783 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X, 784 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K, 785 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X, 786 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K, 787 [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X, 788 [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K, 789 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X, 790 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K, 791 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X, 792 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K, 793 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X, 794 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K, 795 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X, 796 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K, 797 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X, 798 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K, 799 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X, 800 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K, 801 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X, 802 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K, 803 [BPF_ALU | BPF_NEG] = &&ALU_NEG, 804 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE, 805 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE, 806 /* 64 bit ALU operations */ 807 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X, 808 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K, 809 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X, 810 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K, 811 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X, 812 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K, 813 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X, 814 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K, 815 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X, 816 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K, 817 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X, 818 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K, 819 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X, 820 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K, 821 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X, 822 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K, 823 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X, 824 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K, 825 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X, 826 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K, 827 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X, 828 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K, 829 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X, 830 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K, 831 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG, 832 /* Call instruction */ 833 [BPF_JMP | BPF_CALL] = &&JMP_CALL, 834 [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL, 835 /* Jumps */ 836 [BPF_JMP | BPF_JA] = &&JMP_JA, 837 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X, 838 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K, 839 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X, 840 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K, 841 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X, 842 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K, 843 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X, 844 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K, 845 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X, 846 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K, 847 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X, 848 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K, 849 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X, 850 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K, 851 /* Program return */ 852 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT, 853 /* Store instructions */ 854 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B, 855 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H, 856 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W, 857 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW, 858 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W, 859 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW, 860 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B, 861 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H, 862 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W, 863 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW, 864 /* Load instructions */ 865 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B, 866 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H, 867 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W, 868 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW, 869 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W, 870 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H, 871 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B, 872 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W, 873 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H, 874 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B, 875 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW, 876 }; 877 u32 tail_call_cnt = 0; 878 void *ptr; 879 int off; 880 881 #define CONT ({ insn++; goto select_insn; }) 882 #define CONT_JMP ({ insn++; goto select_insn; }) 883 884 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; 885 ARG1 = (u64) (unsigned long) ctx; 886 887 select_insn: 888 goto *jumptable[insn->code]; 889 890 /* ALU */ 891 #define ALU(OPCODE, OP) \ 892 ALU64_##OPCODE##_X: \ 893 DST = DST OP SRC; \ 894 CONT; \ 895 ALU_##OPCODE##_X: \ 896 DST = (u32) DST OP (u32) SRC; \ 897 CONT; \ 898 ALU64_##OPCODE##_K: \ 899 DST = DST OP IMM; \ 900 CONT; \ 901 ALU_##OPCODE##_K: \ 902 DST = (u32) DST OP (u32) IMM; \ 903 CONT; 904 905 ALU(ADD, +) 906 ALU(SUB, -) 907 ALU(AND, &) 908 ALU(OR, |) 909 ALU(LSH, <<) 910 ALU(RSH, >>) 911 ALU(XOR, ^) 912 ALU(MUL, *) 913 #undef ALU 914 ALU_NEG: 915 DST = (u32) -DST; 916 CONT; 917 ALU64_NEG: 918 DST = -DST; 919 CONT; 920 ALU_MOV_X: 921 DST = (u32) SRC; 922 CONT; 923 ALU_MOV_K: 924 DST = (u32) IMM; 925 CONT; 926 ALU64_MOV_X: 927 DST = SRC; 928 CONT; 929 ALU64_MOV_K: 930 DST = IMM; 931 CONT; 932 LD_IMM_DW: 933 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 934 insn++; 935 CONT; 936 ALU64_ARSH_X: 937 (*(s64 *) &DST) >>= SRC; 938 CONT; 939 ALU64_ARSH_K: 940 (*(s64 *) &DST) >>= IMM; 941 CONT; 942 ALU64_MOD_X: 943 if (unlikely(SRC == 0)) 944 return 0; 945 div64_u64_rem(DST, SRC, &tmp); 946 DST = tmp; 947 CONT; 948 ALU_MOD_X: 949 if (unlikely(SRC == 0)) 950 return 0; 951 tmp = (u32) DST; 952 DST = do_div(tmp, (u32) SRC); 953 CONT; 954 ALU64_MOD_K: 955 div64_u64_rem(DST, IMM, &tmp); 956 DST = tmp; 957 CONT; 958 ALU_MOD_K: 959 tmp = (u32) DST; 960 DST = do_div(tmp, (u32) IMM); 961 CONT; 962 ALU64_DIV_X: 963 if (unlikely(SRC == 0)) 964 return 0; 965 DST = div64_u64(DST, SRC); 966 CONT; 967 ALU_DIV_X: 968 if (unlikely(SRC == 0)) 969 return 0; 970 tmp = (u32) DST; 971 do_div(tmp, (u32) SRC); 972 DST = (u32) tmp; 973 CONT; 974 ALU64_DIV_K: 975 DST = div64_u64(DST, IMM); 976 CONT; 977 ALU_DIV_K: 978 tmp = (u32) DST; 979 do_div(tmp, (u32) IMM); 980 DST = (u32) tmp; 981 CONT; 982 ALU_END_TO_BE: 983 switch (IMM) { 984 case 16: 985 DST = (__force u16) cpu_to_be16(DST); 986 break; 987 case 32: 988 DST = (__force u32) cpu_to_be32(DST); 989 break; 990 case 64: 991 DST = (__force u64) cpu_to_be64(DST); 992 break; 993 } 994 CONT; 995 ALU_END_TO_LE: 996 switch (IMM) { 997 case 16: 998 DST = (__force u16) cpu_to_le16(DST); 999 break; 1000 case 32: 1001 DST = (__force u32) cpu_to_le32(DST); 1002 break; 1003 case 64: 1004 DST = (__force u64) cpu_to_le64(DST); 1005 break; 1006 } 1007 CONT; 1008 1009 /* CALL */ 1010 JMP_CALL: 1011 /* Function call scratches BPF_R1-BPF_R5 registers, 1012 * preserves BPF_R6-BPF_R9, and stores return value 1013 * into BPF_R0. 1014 */ 1015 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1016 BPF_R4, BPF_R5); 1017 CONT; 1018 1019 JMP_TAIL_CALL: { 1020 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1021 struct bpf_array *array = container_of(map, struct bpf_array, map); 1022 struct bpf_prog *prog; 1023 u64 index = BPF_R3; 1024 1025 if (unlikely(index >= array->map.max_entries)) 1026 goto out; 1027 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) 1028 goto out; 1029 1030 tail_call_cnt++; 1031 1032 prog = READ_ONCE(array->ptrs[index]); 1033 if (!prog) 1034 goto out; 1035 1036 /* ARG1 at this point is guaranteed to point to CTX from 1037 * the verifier side due to the fact that the tail call is 1038 * handeled like a helper, that is, bpf_tail_call_proto, 1039 * where arg1_type is ARG_PTR_TO_CTX. 1040 */ 1041 insn = prog->insnsi; 1042 goto select_insn; 1043 out: 1044 CONT; 1045 } 1046 /* JMP */ 1047 JMP_JA: 1048 insn += insn->off; 1049 CONT; 1050 JMP_JEQ_X: 1051 if (DST == SRC) { 1052 insn += insn->off; 1053 CONT_JMP; 1054 } 1055 CONT; 1056 JMP_JEQ_K: 1057 if (DST == IMM) { 1058 insn += insn->off; 1059 CONT_JMP; 1060 } 1061 CONT; 1062 JMP_JNE_X: 1063 if (DST != SRC) { 1064 insn += insn->off; 1065 CONT_JMP; 1066 } 1067 CONT; 1068 JMP_JNE_K: 1069 if (DST != IMM) { 1070 insn += insn->off; 1071 CONT_JMP; 1072 } 1073 CONT; 1074 JMP_JGT_X: 1075 if (DST > SRC) { 1076 insn += insn->off; 1077 CONT_JMP; 1078 } 1079 CONT; 1080 JMP_JGT_K: 1081 if (DST > IMM) { 1082 insn += insn->off; 1083 CONT_JMP; 1084 } 1085 CONT; 1086 JMP_JGE_X: 1087 if (DST >= SRC) { 1088 insn += insn->off; 1089 CONT_JMP; 1090 } 1091 CONT; 1092 JMP_JGE_K: 1093 if (DST >= IMM) { 1094 insn += insn->off; 1095 CONT_JMP; 1096 } 1097 CONT; 1098 JMP_JSGT_X: 1099 if (((s64) DST) > ((s64) SRC)) { 1100 insn += insn->off; 1101 CONT_JMP; 1102 } 1103 CONT; 1104 JMP_JSGT_K: 1105 if (((s64) DST) > ((s64) IMM)) { 1106 insn += insn->off; 1107 CONT_JMP; 1108 } 1109 CONT; 1110 JMP_JSGE_X: 1111 if (((s64) DST) >= ((s64) SRC)) { 1112 insn += insn->off; 1113 CONT_JMP; 1114 } 1115 CONT; 1116 JMP_JSGE_K: 1117 if (((s64) DST) >= ((s64) IMM)) { 1118 insn += insn->off; 1119 CONT_JMP; 1120 } 1121 CONT; 1122 JMP_JSET_X: 1123 if (DST & SRC) { 1124 insn += insn->off; 1125 CONT_JMP; 1126 } 1127 CONT; 1128 JMP_JSET_K: 1129 if (DST & IMM) { 1130 insn += insn->off; 1131 CONT_JMP; 1132 } 1133 CONT; 1134 JMP_EXIT: 1135 return BPF_R0; 1136 1137 /* STX and ST and LDX*/ 1138 #define LDST(SIZEOP, SIZE) \ 1139 STX_MEM_##SIZEOP: \ 1140 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 1141 CONT; \ 1142 ST_MEM_##SIZEOP: \ 1143 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 1144 CONT; \ 1145 LDX_MEM_##SIZEOP: \ 1146 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 1147 CONT; 1148 1149 LDST(B, u8) 1150 LDST(H, u16) 1151 LDST(W, u32) 1152 LDST(DW, u64) 1153 #undef LDST 1154 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */ 1155 atomic_add((u32) SRC, (atomic_t *)(unsigned long) 1156 (DST + insn->off)); 1157 CONT; 1158 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */ 1159 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long) 1160 (DST + insn->off)); 1161 CONT; 1162 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */ 1163 off = IMM; 1164 load_word: 1165 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are 1166 * only appearing in the programs where ctx == 1167 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX] 1168 * == BPF_R6, bpf_convert_filter() saves it in BPF_R6, 1169 * internal BPF verifier will check that BPF_R6 == 1170 * ctx. 1171 * 1172 * BPF_ABS and BPF_IND are wrappers of function calls, 1173 * so they scratch BPF_R1-BPF_R5 registers, preserve 1174 * BPF_R6-BPF_R9, and store return value into BPF_R0. 1175 * 1176 * Implicit input: 1177 * ctx == skb == BPF_R6 == CTX 1178 * 1179 * Explicit input: 1180 * SRC == any register 1181 * IMM == 32-bit immediate 1182 * 1183 * Output: 1184 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness 1185 */ 1186 1187 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp); 1188 if (likely(ptr != NULL)) { 1189 BPF_R0 = get_unaligned_be32(ptr); 1190 CONT; 1191 } 1192 1193 return 0; 1194 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */ 1195 off = IMM; 1196 load_half: 1197 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp); 1198 if (likely(ptr != NULL)) { 1199 BPF_R0 = get_unaligned_be16(ptr); 1200 CONT; 1201 } 1202 1203 return 0; 1204 LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */ 1205 off = IMM; 1206 load_byte: 1207 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp); 1208 if (likely(ptr != NULL)) { 1209 BPF_R0 = *(u8 *)ptr; 1210 CONT; 1211 } 1212 1213 return 0; 1214 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */ 1215 off = IMM + SRC; 1216 goto load_word; 1217 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */ 1218 off = IMM + SRC; 1219 goto load_half; 1220 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */ 1221 off = IMM + SRC; 1222 goto load_byte; 1223 1224 default_label: 1225 /* If we ever reach this, we have a bug somewhere. */ 1226 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code); 1227 return 0; 1228 } 1229 STACK_FRAME_NON_STANDARD(__bpf_prog_run); /* jump table */ 1230 1231 bool bpf_prog_array_compatible(struct bpf_array *array, 1232 const struct bpf_prog *fp) 1233 { 1234 if (!array->owner_prog_type) { 1235 /* There's no owner yet where we could check for 1236 * compatibility. 1237 */ 1238 array->owner_prog_type = fp->type; 1239 array->owner_jited = fp->jited; 1240 1241 return true; 1242 } 1243 1244 return array->owner_prog_type == fp->type && 1245 array->owner_jited == fp->jited; 1246 } 1247 1248 static int bpf_check_tail_call(const struct bpf_prog *fp) 1249 { 1250 struct bpf_prog_aux *aux = fp->aux; 1251 int i; 1252 1253 for (i = 0; i < aux->used_map_cnt; i++) { 1254 struct bpf_map *map = aux->used_maps[i]; 1255 struct bpf_array *array; 1256 1257 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) 1258 continue; 1259 1260 array = container_of(map, struct bpf_array, map); 1261 if (!bpf_prog_array_compatible(array, fp)) 1262 return -EINVAL; 1263 } 1264 1265 return 0; 1266 } 1267 1268 /** 1269 * bpf_prog_select_runtime - select exec runtime for BPF program 1270 * @fp: bpf_prog populated with internal BPF program 1271 * @err: pointer to error variable 1272 * 1273 * Try to JIT eBPF program, if JIT is not available, use interpreter. 1274 * The BPF program will be executed via BPF_PROG_RUN() macro. 1275 */ 1276 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 1277 { 1278 fp->bpf_func = (void *) __bpf_prog_run; 1279 1280 /* eBPF JITs can rewrite the program in case constant 1281 * blinding is active. However, in case of error during 1282 * blinding, bpf_int_jit_compile() must always return a 1283 * valid program, which in this case would simply not 1284 * be JITed, but falls back to the interpreter. 1285 */ 1286 fp = bpf_int_jit_compile(fp); 1287 bpf_prog_lock_ro(fp); 1288 1289 /* The tail call compatibility check can only be done at 1290 * this late stage as we need to determine, if we deal 1291 * with JITed or non JITed program concatenations and not 1292 * all eBPF JITs might immediately support all features. 1293 */ 1294 *err = bpf_check_tail_call(fp); 1295 1296 return fp; 1297 } 1298 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 1299 1300 static void bpf_prog_free_deferred(struct work_struct *work) 1301 { 1302 struct bpf_prog_aux *aux; 1303 1304 aux = container_of(work, struct bpf_prog_aux, work); 1305 bpf_jit_free(aux->prog); 1306 } 1307 1308 /* Free internal BPF program */ 1309 void bpf_prog_free(struct bpf_prog *fp) 1310 { 1311 struct bpf_prog_aux *aux = fp->aux; 1312 1313 INIT_WORK(&aux->work, bpf_prog_free_deferred); 1314 schedule_work(&aux->work); 1315 } 1316 EXPORT_SYMBOL_GPL(bpf_prog_free); 1317 1318 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 1319 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 1320 1321 void bpf_user_rnd_init_once(void) 1322 { 1323 prandom_init_once(&bpf_user_rnd_state); 1324 } 1325 1326 BPF_CALL_0(bpf_user_rnd_u32) 1327 { 1328 /* Should someone ever have the rather unwise idea to use some 1329 * of the registers passed into this function, then note that 1330 * this function is called from native eBPF and classic-to-eBPF 1331 * transformations. Register assignments from both sides are 1332 * different, f.e. classic always sets fn(ctx, A, X) here. 1333 */ 1334 struct rnd_state *state; 1335 u32 res; 1336 1337 state = &get_cpu_var(bpf_user_rnd_state); 1338 res = prandom_u32_state(state); 1339 put_cpu_var(bpf_user_rnd_state); 1340 1341 return res; 1342 } 1343 1344 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 1345 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 1346 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 1347 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 1348 1349 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 1350 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 1351 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 1352 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 1353 1354 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 1355 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 1356 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 1357 1358 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 1359 { 1360 return NULL; 1361 } 1362 1363 u64 __weak 1364 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 1365 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 1366 { 1367 return -ENOTSUPP; 1368 } 1369 1370 /* Always built-in helper functions. */ 1371 const struct bpf_func_proto bpf_tail_call_proto = { 1372 .func = NULL, 1373 .gpl_only = false, 1374 .ret_type = RET_VOID, 1375 .arg1_type = ARG_PTR_TO_CTX, 1376 .arg2_type = ARG_CONST_MAP_PTR, 1377 .arg3_type = ARG_ANYTHING, 1378 }; 1379 1380 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 1381 * It is encouraged to implement bpf_int_jit_compile() instead, so that 1382 * eBPF and implicitly also cBPF can get JITed! 1383 */ 1384 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 1385 { 1386 return prog; 1387 } 1388 1389 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 1390 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 1391 */ 1392 void __weak bpf_jit_compile(struct bpf_prog *prog) 1393 { 1394 } 1395 1396 bool __weak bpf_helper_changes_pkt_data(void *func) 1397 { 1398 return false; 1399 } 1400 1401 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 1402 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 1403 */ 1404 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 1405 int len) 1406 { 1407 return -EFAULT; 1408 } 1409 1410 /* All definitions of tracepoints related to BPF. */ 1411 #define CREATE_TRACE_POINTS 1412 #include <linux/bpf_trace.h> 1413 1414 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 1415 1416 EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_get_type); 1417 EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_put_rcu); 1418