1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Linux Socket Filter - Kernel level socket filtering 4 * 5 * Based on the design of the Berkeley Packet Filter. The new 6 * internal format has been designed by PLUMgrid: 7 * 8 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com 9 * 10 * Authors: 11 * 12 * Jay Schulist <jschlst@samba.org> 13 * Alexei Starovoitov <ast@plumgrid.com> 14 * Daniel Borkmann <dborkman@redhat.com> 15 * 16 * Andi Kleen - Fix a few bad bugs and races. 17 * Kris Katterjohn - Added many additional checks in bpf_check_classic() 18 */ 19 20 #include <uapi/linux/btf.h> 21 #include <linux/filter.h> 22 #include <linux/skbuff.h> 23 #include <linux/vmalloc.h> 24 #include <linux/random.h> 25 #include <linux/moduleloader.h> 26 #include <linux/bpf.h> 27 #include <linux/btf.h> 28 #include <linux/objtool.h> 29 #include <linux/rbtree_latch.h> 30 #include <linux/kallsyms.h> 31 #include <linux/rcupdate.h> 32 #include <linux/perf_event.h> 33 #include <linux/extable.h> 34 #include <linux/log2.h> 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 AX regs[BPF_REG_AX] 55 #define ARG1 regs[BPF_REG_ARG1] 56 #define CTX regs[BPF_REG_CTX] 57 #define IMM insn->imm 58 59 /* No hurry in this branch 60 * 61 * Exported for the bpf jit load helper. 62 */ 63 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 64 { 65 u8 *ptr = NULL; 66 67 if (k >= SKF_NET_OFF) 68 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 69 else if (k >= SKF_LL_OFF) 70 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 71 72 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 73 return ptr; 74 75 return NULL; 76 } 77 78 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags) 79 { 80 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | 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); 86 if (fp == NULL) 87 return NULL; 88 89 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags); 90 if (aux == NULL) { 91 vfree(fp); 92 return NULL; 93 } 94 95 fp->pages = size / PAGE_SIZE; 96 fp->aux = aux; 97 fp->aux->prog = fp; 98 fp->jit_requested = ebpf_jit_enabled(); 99 100 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); 101 mutex_init(&fp->aux->used_maps_mutex); 102 mutex_init(&fp->aux->dst_mutex); 103 104 return fp; 105 } 106 107 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 108 { 109 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 110 struct bpf_prog *prog; 111 int cpu; 112 113 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); 114 if (!prog) 115 return NULL; 116 117 prog->aux->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); 118 if (!prog->aux->stats) { 119 kfree(prog->aux); 120 vfree(prog); 121 return NULL; 122 } 123 124 for_each_possible_cpu(cpu) { 125 struct bpf_prog_stats *pstats; 126 127 pstats = per_cpu_ptr(prog->aux->stats, cpu); 128 u64_stats_init(&pstats->syncp); 129 } 130 return prog; 131 } 132 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 133 134 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 135 { 136 if (!prog->aux->nr_linfo || !prog->jit_requested) 137 return 0; 138 139 prog->aux->jited_linfo = kcalloc(prog->aux->nr_linfo, 140 sizeof(*prog->aux->jited_linfo), 141 GFP_KERNEL | __GFP_NOWARN); 142 if (!prog->aux->jited_linfo) 143 return -ENOMEM; 144 145 return 0; 146 } 147 148 void bpf_prog_free_jited_linfo(struct bpf_prog *prog) 149 { 150 kfree(prog->aux->jited_linfo); 151 prog->aux->jited_linfo = NULL; 152 } 153 154 void bpf_prog_free_unused_jited_linfo(struct bpf_prog *prog) 155 { 156 if (prog->aux->jited_linfo && !prog->aux->jited_linfo[0]) 157 bpf_prog_free_jited_linfo(prog); 158 } 159 160 /* The jit engine is responsible to provide an array 161 * for insn_off to the jited_off mapping (insn_to_jit_off). 162 * 163 * The idx to this array is the insn_off. Hence, the insn_off 164 * here is relative to the prog itself instead of the main prog. 165 * This array has one entry for each xlated bpf insn. 166 * 167 * jited_off is the byte off to the last byte of the jited insn. 168 * 169 * Hence, with 170 * insn_start: 171 * The first bpf insn off of the prog. The insn off 172 * here is relative to the main prog. 173 * e.g. if prog is a subprog, insn_start > 0 174 * linfo_idx: 175 * The prog's idx to prog->aux->linfo and jited_linfo 176 * 177 * jited_linfo[linfo_idx] = prog->bpf_func 178 * 179 * For i > linfo_idx, 180 * 181 * jited_linfo[i] = prog->bpf_func + 182 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 183 */ 184 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 185 const u32 *insn_to_jit_off) 186 { 187 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 188 const struct bpf_line_info *linfo; 189 void **jited_linfo; 190 191 if (!prog->aux->jited_linfo) 192 /* Userspace did not provide linfo */ 193 return; 194 195 linfo_idx = prog->aux->linfo_idx; 196 linfo = &prog->aux->linfo[linfo_idx]; 197 insn_start = linfo[0].insn_off; 198 insn_end = insn_start + prog->len; 199 200 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 201 jited_linfo[0] = prog->bpf_func; 202 203 nr_linfo = prog->aux->nr_linfo - linfo_idx; 204 205 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 206 /* The verifier ensures that linfo[i].insn_off is 207 * strictly increasing 208 */ 209 jited_linfo[i] = prog->bpf_func + 210 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 211 } 212 213 void bpf_prog_free_linfo(struct bpf_prog *prog) 214 { 215 bpf_prog_free_jited_linfo(prog); 216 kvfree(prog->aux->linfo); 217 } 218 219 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 220 gfp_t gfp_extra_flags) 221 { 222 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 223 struct bpf_prog *fp; 224 u32 pages, delta; 225 int ret; 226 227 size = round_up(size, PAGE_SIZE); 228 pages = size / PAGE_SIZE; 229 if (pages <= fp_old->pages) 230 return fp_old; 231 232 delta = pages - fp_old->pages; 233 ret = __bpf_prog_charge(fp_old->aux->user, delta); 234 if (ret) 235 return NULL; 236 237 fp = __vmalloc(size, gfp_flags); 238 if (fp == NULL) { 239 __bpf_prog_uncharge(fp_old->aux->user, delta); 240 } else { 241 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 242 fp->pages = pages; 243 fp->aux->prog = fp; 244 245 /* We keep fp->aux from fp_old around in the new 246 * reallocated structure. 247 */ 248 fp_old->aux = NULL; 249 __bpf_prog_free(fp_old); 250 } 251 252 return fp; 253 } 254 255 void __bpf_prog_free(struct bpf_prog *fp) 256 { 257 if (fp->aux) { 258 mutex_destroy(&fp->aux->used_maps_mutex); 259 mutex_destroy(&fp->aux->dst_mutex); 260 free_percpu(fp->aux->stats); 261 kfree(fp->aux->poke_tab); 262 kfree(fp->aux); 263 } 264 vfree(fp); 265 } 266 267 int bpf_prog_calc_tag(struct bpf_prog *fp) 268 { 269 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64); 270 u32 raw_size = bpf_prog_tag_scratch_size(fp); 271 u32 digest[SHA1_DIGEST_WORDS]; 272 u32 ws[SHA1_WORKSPACE_WORDS]; 273 u32 i, bsize, psize, blocks; 274 struct bpf_insn *dst; 275 bool was_ld_map; 276 u8 *raw, *todo; 277 __be32 *result; 278 __be64 *bits; 279 280 raw = vmalloc(raw_size); 281 if (!raw) 282 return -ENOMEM; 283 284 sha1_init(digest); 285 memset(ws, 0, sizeof(ws)); 286 287 /* We need to take out the map fd for the digest calculation 288 * since they are unstable from user space side. 289 */ 290 dst = (void *)raw; 291 for (i = 0, was_ld_map = false; i < fp->len; i++) { 292 dst[i] = fp->insnsi[i]; 293 if (!was_ld_map && 294 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 295 (dst[i].src_reg == BPF_PSEUDO_MAP_FD || 296 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { 297 was_ld_map = true; 298 dst[i].imm = 0; 299 } else if (was_ld_map && 300 dst[i].code == 0 && 301 dst[i].dst_reg == 0 && 302 dst[i].src_reg == 0 && 303 dst[i].off == 0) { 304 was_ld_map = false; 305 dst[i].imm = 0; 306 } else { 307 was_ld_map = false; 308 } 309 } 310 311 psize = bpf_prog_insn_size(fp); 312 memset(&raw[psize], 0, raw_size - psize); 313 raw[psize++] = 0x80; 314 315 bsize = round_up(psize, SHA1_BLOCK_SIZE); 316 blocks = bsize / SHA1_BLOCK_SIZE; 317 todo = raw; 318 if (bsize - psize >= sizeof(__be64)) { 319 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 320 } else { 321 bits = (__be64 *)(todo + bsize + bits_offset); 322 blocks++; 323 } 324 *bits = cpu_to_be64((psize - 1) << 3); 325 326 while (blocks--) { 327 sha1_transform(digest, todo, ws); 328 todo += SHA1_BLOCK_SIZE; 329 } 330 331 result = (__force __be32 *)digest; 332 for (i = 0; i < SHA1_DIGEST_WORDS; i++) 333 result[i] = cpu_to_be32(digest[i]); 334 memcpy(fp->tag, result, sizeof(fp->tag)); 335 336 vfree(raw); 337 return 0; 338 } 339 340 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, 341 s32 end_new, s32 curr, const bool probe_pass) 342 { 343 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 344 s32 delta = end_new - end_old; 345 s64 imm = insn->imm; 346 347 if (curr < pos && curr + imm + 1 >= end_old) 348 imm += delta; 349 else if (curr >= end_new && curr + imm + 1 < end_new) 350 imm -= delta; 351 if (imm < imm_min || imm > imm_max) 352 return -ERANGE; 353 if (!probe_pass) 354 insn->imm = imm; 355 return 0; 356 } 357 358 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, 359 s32 end_new, s32 curr, const bool probe_pass) 360 { 361 const s32 off_min = S16_MIN, off_max = S16_MAX; 362 s32 delta = end_new - end_old; 363 s32 off = insn->off; 364 365 if (curr < pos && curr + off + 1 >= end_old) 366 off += delta; 367 else if (curr >= end_new && curr + off + 1 < end_new) 368 off -= delta; 369 if (off < off_min || off > off_max) 370 return -ERANGE; 371 if (!probe_pass) 372 insn->off = off; 373 return 0; 374 } 375 376 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 377 s32 end_new, const bool probe_pass) 378 { 379 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); 380 struct bpf_insn *insn = prog->insnsi; 381 int ret = 0; 382 383 for (i = 0; i < insn_cnt; i++, insn++) { 384 u8 code; 385 386 /* In the probing pass we still operate on the original, 387 * unpatched image in order to check overflows before we 388 * do any other adjustments. Therefore skip the patchlet. 389 */ 390 if (probe_pass && i == pos) { 391 i = end_new; 392 insn = prog->insnsi + end_old; 393 } 394 code = insn->code; 395 if ((BPF_CLASS(code) != BPF_JMP && 396 BPF_CLASS(code) != BPF_JMP32) || 397 BPF_OP(code) == BPF_EXIT) 398 continue; 399 /* Adjust offset of jmps if we cross patch boundaries. */ 400 if (BPF_OP(code) == BPF_CALL) { 401 if (insn->src_reg != BPF_PSEUDO_CALL) 402 continue; 403 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 404 end_new, i, probe_pass); 405 } else { 406 ret = bpf_adj_delta_to_off(insn, pos, end_old, 407 end_new, i, probe_pass); 408 } 409 if (ret) 410 break; 411 } 412 413 return ret; 414 } 415 416 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 417 { 418 struct bpf_line_info *linfo; 419 u32 i, nr_linfo; 420 421 nr_linfo = prog->aux->nr_linfo; 422 if (!nr_linfo || !delta) 423 return; 424 425 linfo = prog->aux->linfo; 426 427 for (i = 0; i < nr_linfo; i++) 428 if (off < linfo[i].insn_off) 429 break; 430 431 /* Push all off < linfo[i].insn_off by delta */ 432 for (; i < nr_linfo; i++) 433 linfo[i].insn_off += delta; 434 } 435 436 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 437 const struct bpf_insn *patch, u32 len) 438 { 439 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 440 const u32 cnt_max = S16_MAX; 441 struct bpf_prog *prog_adj; 442 int err; 443 444 /* Since our patchlet doesn't expand the image, we're done. */ 445 if (insn_delta == 0) { 446 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 447 return prog; 448 } 449 450 insn_adj_cnt = prog->len + insn_delta; 451 452 /* Reject anything that would potentially let the insn->off 453 * target overflow when we have excessive program expansions. 454 * We need to probe here before we do any reallocation where 455 * we afterwards may not fail anymore. 456 */ 457 if (insn_adj_cnt > cnt_max && 458 (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) 459 return ERR_PTR(err); 460 461 /* Several new instructions need to be inserted. Make room 462 * for them. Likely, there's no need for a new allocation as 463 * last page could have large enough tailroom. 464 */ 465 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 466 GFP_USER); 467 if (!prog_adj) 468 return ERR_PTR(-ENOMEM); 469 470 prog_adj->len = insn_adj_cnt; 471 472 /* Patching happens in 3 steps: 473 * 474 * 1) Move over tail of insnsi from next instruction onwards, 475 * so we can patch the single target insn with one or more 476 * new ones (patching is always from 1 to n insns, n > 0). 477 * 2) Inject new instructions at the target location. 478 * 3) Adjust branch offsets if necessary. 479 */ 480 insn_rest = insn_adj_cnt - off - len; 481 482 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 483 sizeof(*patch) * insn_rest); 484 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 485 486 /* We are guaranteed to not fail at this point, otherwise 487 * the ship has sailed to reverse to the original state. An 488 * overflow cannot happen at this point. 489 */ 490 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); 491 492 bpf_adj_linfo(prog_adj, off, insn_delta); 493 494 return prog_adj; 495 } 496 497 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) 498 { 499 /* Branch offsets can't overflow when program is shrinking, no need 500 * to call bpf_adj_branches(..., true) here 501 */ 502 memmove(prog->insnsi + off, prog->insnsi + off + cnt, 503 sizeof(struct bpf_insn) * (prog->len - off - cnt)); 504 prog->len -= cnt; 505 506 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); 507 } 508 509 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 510 { 511 int i; 512 513 for (i = 0; i < fp->aux->func_cnt; i++) 514 bpf_prog_kallsyms_del(fp->aux->func[i]); 515 } 516 517 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 518 { 519 bpf_prog_kallsyms_del_subprogs(fp); 520 bpf_prog_kallsyms_del(fp); 521 } 522 523 #ifdef CONFIG_BPF_JIT 524 /* All BPF JIT sysctl knobs here. */ 525 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 526 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 527 int bpf_jit_harden __read_mostly; 528 long bpf_jit_limit __read_mostly; 529 530 static void 531 bpf_prog_ksym_set_addr(struct bpf_prog *prog) 532 { 533 const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog); 534 unsigned long addr = (unsigned long)hdr; 535 536 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 537 538 prog->aux->ksym.start = (unsigned long) prog->bpf_func; 539 prog->aux->ksym.end = addr + hdr->pages * PAGE_SIZE; 540 } 541 542 static void 543 bpf_prog_ksym_set_name(struct bpf_prog *prog) 544 { 545 char *sym = prog->aux->ksym.name; 546 const char *end = sym + KSYM_NAME_LEN; 547 const struct btf_type *type; 548 const char *func_name; 549 550 BUILD_BUG_ON(sizeof("bpf_prog_") + 551 sizeof(prog->tag) * 2 + 552 /* name has been null terminated. 553 * We should need +1 for the '_' preceding 554 * the name. However, the null character 555 * is double counted between the name and the 556 * sizeof("bpf_prog_") above, so we omit 557 * the +1 here. 558 */ 559 sizeof(prog->aux->name) > KSYM_NAME_LEN); 560 561 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 562 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 563 564 /* prog->aux->name will be ignored if full btf name is available */ 565 if (prog->aux->func_info_cnt) { 566 type = btf_type_by_id(prog->aux->btf, 567 prog->aux->func_info[prog->aux->func_idx].type_id); 568 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 569 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 570 return; 571 } 572 573 if (prog->aux->name[0]) 574 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 575 else 576 *sym = 0; 577 } 578 579 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) 580 { 581 return container_of(n, struct bpf_ksym, tnode)->start; 582 } 583 584 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 585 struct latch_tree_node *b) 586 { 587 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); 588 } 589 590 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 591 { 592 unsigned long val = (unsigned long)key; 593 const struct bpf_ksym *ksym; 594 595 ksym = container_of(n, struct bpf_ksym, tnode); 596 597 if (val < ksym->start) 598 return -1; 599 if (val >= ksym->end) 600 return 1; 601 602 return 0; 603 } 604 605 static const struct latch_tree_ops bpf_tree_ops = { 606 .less = bpf_tree_less, 607 .comp = bpf_tree_comp, 608 }; 609 610 static DEFINE_SPINLOCK(bpf_lock); 611 static LIST_HEAD(bpf_kallsyms); 612 static struct latch_tree_root bpf_tree __cacheline_aligned; 613 614 void bpf_ksym_add(struct bpf_ksym *ksym) 615 { 616 spin_lock_bh(&bpf_lock); 617 WARN_ON_ONCE(!list_empty(&ksym->lnode)); 618 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); 619 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 620 spin_unlock_bh(&bpf_lock); 621 } 622 623 static void __bpf_ksym_del(struct bpf_ksym *ksym) 624 { 625 if (list_empty(&ksym->lnode)) 626 return; 627 628 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 629 list_del_rcu(&ksym->lnode); 630 } 631 632 void bpf_ksym_del(struct bpf_ksym *ksym) 633 { 634 spin_lock_bh(&bpf_lock); 635 __bpf_ksym_del(ksym); 636 spin_unlock_bh(&bpf_lock); 637 } 638 639 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 640 { 641 return fp->jited && !bpf_prog_was_classic(fp); 642 } 643 644 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp) 645 { 646 return list_empty(&fp->aux->ksym.lnode) || 647 fp->aux->ksym.lnode.prev == LIST_POISON2; 648 } 649 650 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 651 { 652 if (!bpf_prog_kallsyms_candidate(fp) || 653 !bpf_capable()) 654 return; 655 656 bpf_prog_ksym_set_addr(fp); 657 bpf_prog_ksym_set_name(fp); 658 fp->aux->ksym.prog = true; 659 660 bpf_ksym_add(&fp->aux->ksym); 661 } 662 663 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 664 { 665 if (!bpf_prog_kallsyms_candidate(fp)) 666 return; 667 668 bpf_ksym_del(&fp->aux->ksym); 669 } 670 671 static struct bpf_ksym *bpf_ksym_find(unsigned long addr) 672 { 673 struct latch_tree_node *n; 674 675 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 676 return n ? container_of(n, struct bpf_ksym, tnode) : NULL; 677 } 678 679 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, 680 unsigned long *off, char *sym) 681 { 682 struct bpf_ksym *ksym; 683 char *ret = NULL; 684 685 rcu_read_lock(); 686 ksym = bpf_ksym_find(addr); 687 if (ksym) { 688 unsigned long symbol_start = ksym->start; 689 unsigned long symbol_end = ksym->end; 690 691 strncpy(sym, ksym->name, KSYM_NAME_LEN); 692 693 ret = sym; 694 if (size) 695 *size = symbol_end - symbol_start; 696 if (off) 697 *off = addr - symbol_start; 698 } 699 rcu_read_unlock(); 700 701 return ret; 702 } 703 704 bool is_bpf_text_address(unsigned long addr) 705 { 706 bool ret; 707 708 rcu_read_lock(); 709 ret = bpf_ksym_find(addr) != NULL; 710 rcu_read_unlock(); 711 712 return ret; 713 } 714 715 static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) 716 { 717 struct bpf_ksym *ksym = bpf_ksym_find(addr); 718 719 return ksym && ksym->prog ? 720 container_of(ksym, struct bpf_prog_aux, ksym)->prog : 721 NULL; 722 } 723 724 const struct exception_table_entry *search_bpf_extables(unsigned long addr) 725 { 726 const struct exception_table_entry *e = NULL; 727 struct bpf_prog *prog; 728 729 rcu_read_lock(); 730 prog = bpf_prog_ksym_find(addr); 731 if (!prog) 732 goto out; 733 if (!prog->aux->num_exentries) 734 goto out; 735 736 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); 737 out: 738 rcu_read_unlock(); 739 return e; 740 } 741 742 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 743 char *sym) 744 { 745 struct bpf_ksym *ksym; 746 unsigned int it = 0; 747 int ret = -ERANGE; 748 749 if (!bpf_jit_kallsyms_enabled()) 750 return ret; 751 752 rcu_read_lock(); 753 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { 754 if (it++ != symnum) 755 continue; 756 757 strncpy(sym, ksym->name, KSYM_NAME_LEN); 758 759 *value = ksym->start; 760 *type = BPF_SYM_ELF_TYPE; 761 762 ret = 0; 763 break; 764 } 765 rcu_read_unlock(); 766 767 return ret; 768 } 769 770 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, 771 struct bpf_jit_poke_descriptor *poke) 772 { 773 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; 774 static const u32 poke_tab_max = 1024; 775 u32 slot = prog->aux->size_poke_tab; 776 u32 size = slot + 1; 777 778 if (size > poke_tab_max) 779 return -ENOSPC; 780 if (poke->tailcall_target || poke->tailcall_target_stable || 781 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) 782 return -EINVAL; 783 784 switch (poke->reason) { 785 case BPF_POKE_REASON_TAIL_CALL: 786 if (!poke->tail_call.map) 787 return -EINVAL; 788 break; 789 default: 790 return -EINVAL; 791 } 792 793 tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL); 794 if (!tab) 795 return -ENOMEM; 796 797 memcpy(&tab[slot], poke, sizeof(*poke)); 798 prog->aux->size_poke_tab = size; 799 prog->aux->poke_tab = tab; 800 801 return slot; 802 } 803 804 static atomic_long_t bpf_jit_current; 805 806 /* Can be overridden by an arch's JIT compiler if it has a custom, 807 * dedicated BPF backend memory area, or if neither of the two 808 * below apply. 809 */ 810 u64 __weak bpf_jit_alloc_exec_limit(void) 811 { 812 #if defined(MODULES_VADDR) 813 return MODULES_END - MODULES_VADDR; 814 #else 815 return VMALLOC_END - VMALLOC_START; 816 #endif 817 } 818 819 static int __init bpf_jit_charge_init(void) 820 { 821 /* Only used as heuristic here to derive limit. */ 822 bpf_jit_limit = min_t(u64, round_up(bpf_jit_alloc_exec_limit() >> 2, 823 PAGE_SIZE), LONG_MAX); 824 return 0; 825 } 826 pure_initcall(bpf_jit_charge_init); 827 828 static int bpf_jit_charge_modmem(u32 pages) 829 { 830 if (atomic_long_add_return(pages, &bpf_jit_current) > 831 (bpf_jit_limit >> PAGE_SHIFT)) { 832 if (!capable(CAP_SYS_ADMIN)) { 833 atomic_long_sub(pages, &bpf_jit_current); 834 return -EPERM; 835 } 836 } 837 838 return 0; 839 } 840 841 static void bpf_jit_uncharge_modmem(u32 pages) 842 { 843 atomic_long_sub(pages, &bpf_jit_current); 844 } 845 846 void *__weak bpf_jit_alloc_exec(unsigned long size) 847 { 848 return module_alloc(size); 849 } 850 851 void __weak bpf_jit_free_exec(void *addr) 852 { 853 module_memfree(addr); 854 } 855 856 struct bpf_binary_header * 857 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 858 unsigned int alignment, 859 bpf_jit_fill_hole_t bpf_fill_ill_insns) 860 { 861 struct bpf_binary_header *hdr; 862 u32 size, hole, start, pages; 863 864 WARN_ON_ONCE(!is_power_of_2(alignment) || 865 alignment > BPF_IMAGE_ALIGNMENT); 866 867 /* Most of BPF filters are really small, but if some of them 868 * fill a page, allow at least 128 extra bytes to insert a 869 * random section of illegal instructions. 870 */ 871 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 872 pages = size / PAGE_SIZE; 873 874 if (bpf_jit_charge_modmem(pages)) 875 return NULL; 876 hdr = bpf_jit_alloc_exec(size); 877 if (!hdr) { 878 bpf_jit_uncharge_modmem(pages); 879 return NULL; 880 } 881 882 /* Fill space with illegal/arch-dep instructions. */ 883 bpf_fill_ill_insns(hdr, size); 884 885 hdr->pages = pages; 886 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 887 PAGE_SIZE - sizeof(*hdr)); 888 start = (get_random_int() % hole) & ~(alignment - 1); 889 890 /* Leave a random number of instructions before BPF code. */ 891 *image_ptr = &hdr->image[start]; 892 893 return hdr; 894 } 895 896 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 897 { 898 u32 pages = hdr->pages; 899 900 bpf_jit_free_exec(hdr); 901 bpf_jit_uncharge_modmem(pages); 902 } 903 904 /* This symbol is only overridden by archs that have different 905 * requirements than the usual eBPF JITs, f.e. when they only 906 * implement cBPF JIT, do not set images read-only, etc. 907 */ 908 void __weak bpf_jit_free(struct bpf_prog *fp) 909 { 910 if (fp->jited) { 911 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 912 913 bpf_jit_binary_free(hdr); 914 915 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 916 } 917 918 bpf_prog_unlock_free(fp); 919 } 920 921 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 922 const struct bpf_insn *insn, bool extra_pass, 923 u64 *func_addr, bool *func_addr_fixed) 924 { 925 s16 off = insn->off; 926 s32 imm = insn->imm; 927 u8 *addr; 928 929 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 930 if (!*func_addr_fixed) { 931 /* Place-holder address till the last pass has collected 932 * all addresses for JITed subprograms in which case we 933 * can pick them up from prog->aux. 934 */ 935 if (!extra_pass) 936 addr = NULL; 937 else if (prog->aux->func && 938 off >= 0 && off < prog->aux->func_cnt) 939 addr = (u8 *)prog->aux->func[off]->bpf_func; 940 else 941 return -EINVAL; 942 } else { 943 /* Address of a BPF helper call. Since part of the core 944 * kernel, it's always at a fixed location. __bpf_call_base 945 * and the helper with imm relative to it are both in core 946 * kernel. 947 */ 948 addr = (u8 *)__bpf_call_base + imm; 949 } 950 951 *func_addr = (unsigned long)addr; 952 return 0; 953 } 954 955 static int bpf_jit_blind_insn(const struct bpf_insn *from, 956 const struct bpf_insn *aux, 957 struct bpf_insn *to_buff, 958 bool emit_zext) 959 { 960 struct bpf_insn *to = to_buff; 961 u32 imm_rnd = get_random_int(); 962 s16 off; 963 964 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 965 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 966 967 /* Constraints on AX register: 968 * 969 * AX register is inaccessible from user space. It is mapped in 970 * all JITs, and used here for constant blinding rewrites. It is 971 * typically "stateless" meaning its contents are only valid within 972 * the executed instruction, but not across several instructions. 973 * There are a few exceptions however which are further detailed 974 * below. 975 * 976 * Constant blinding is only used by JITs, not in the interpreter. 977 * The interpreter uses AX in some occasions as a local temporary 978 * register e.g. in DIV or MOD instructions. 979 * 980 * In restricted circumstances, the verifier can also use the AX 981 * register for rewrites as long as they do not interfere with 982 * the above cases! 983 */ 984 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 985 goto out; 986 987 if (from->imm == 0 && 988 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 989 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 990 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 991 goto out; 992 } 993 994 switch (from->code) { 995 case BPF_ALU | BPF_ADD | BPF_K: 996 case BPF_ALU | BPF_SUB | BPF_K: 997 case BPF_ALU | BPF_AND | BPF_K: 998 case BPF_ALU | BPF_OR | BPF_K: 999 case BPF_ALU | BPF_XOR | BPF_K: 1000 case BPF_ALU | BPF_MUL | BPF_K: 1001 case BPF_ALU | BPF_MOV | BPF_K: 1002 case BPF_ALU | BPF_DIV | BPF_K: 1003 case BPF_ALU | BPF_MOD | BPF_K: 1004 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1005 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1006 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 1007 break; 1008 1009 case BPF_ALU64 | BPF_ADD | BPF_K: 1010 case BPF_ALU64 | BPF_SUB | BPF_K: 1011 case BPF_ALU64 | BPF_AND | BPF_K: 1012 case BPF_ALU64 | BPF_OR | BPF_K: 1013 case BPF_ALU64 | BPF_XOR | BPF_K: 1014 case BPF_ALU64 | BPF_MUL | BPF_K: 1015 case BPF_ALU64 | BPF_MOV | BPF_K: 1016 case BPF_ALU64 | BPF_DIV | BPF_K: 1017 case BPF_ALU64 | BPF_MOD | BPF_K: 1018 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1019 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1020 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 1021 break; 1022 1023 case BPF_JMP | BPF_JEQ | BPF_K: 1024 case BPF_JMP | BPF_JNE | BPF_K: 1025 case BPF_JMP | BPF_JGT | BPF_K: 1026 case BPF_JMP | BPF_JLT | BPF_K: 1027 case BPF_JMP | BPF_JGE | BPF_K: 1028 case BPF_JMP | BPF_JLE | BPF_K: 1029 case BPF_JMP | BPF_JSGT | BPF_K: 1030 case BPF_JMP | BPF_JSLT | BPF_K: 1031 case BPF_JMP | BPF_JSGE | BPF_K: 1032 case BPF_JMP | BPF_JSLE | BPF_K: 1033 case BPF_JMP | BPF_JSET | BPF_K: 1034 /* Accommodate for extra offset in case of a backjump. */ 1035 off = from->off; 1036 if (off < 0) 1037 off -= 2; 1038 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1039 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1040 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1041 break; 1042 1043 case BPF_JMP32 | BPF_JEQ | BPF_K: 1044 case BPF_JMP32 | BPF_JNE | BPF_K: 1045 case BPF_JMP32 | BPF_JGT | BPF_K: 1046 case BPF_JMP32 | BPF_JLT | BPF_K: 1047 case BPF_JMP32 | BPF_JGE | BPF_K: 1048 case BPF_JMP32 | BPF_JLE | BPF_K: 1049 case BPF_JMP32 | BPF_JSGT | BPF_K: 1050 case BPF_JMP32 | BPF_JSLT | BPF_K: 1051 case BPF_JMP32 | BPF_JSGE | BPF_K: 1052 case BPF_JMP32 | BPF_JSLE | BPF_K: 1053 case BPF_JMP32 | BPF_JSET | BPF_K: 1054 /* Accommodate for extra offset in case of a backjump. */ 1055 off = from->off; 1056 if (off < 0) 1057 off -= 2; 1058 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1059 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1060 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1061 off); 1062 break; 1063 1064 case BPF_LD | BPF_IMM | BPF_DW: 1065 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1066 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1067 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1068 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1069 break; 1070 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1071 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1072 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1073 if (emit_zext) 1074 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1075 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1076 break; 1077 1078 case BPF_ST | BPF_MEM | BPF_DW: 1079 case BPF_ST | BPF_MEM | BPF_W: 1080 case BPF_ST | BPF_MEM | BPF_H: 1081 case BPF_ST | BPF_MEM | BPF_B: 1082 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1083 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1084 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1085 break; 1086 } 1087 out: 1088 return to - to_buff; 1089 } 1090 1091 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1092 gfp_t gfp_extra_flags) 1093 { 1094 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1095 struct bpf_prog *fp; 1096 1097 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1098 if (fp != NULL) { 1099 /* aux->prog still points to the fp_other one, so 1100 * when promoting the clone to the real program, 1101 * this still needs to be adapted. 1102 */ 1103 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1104 } 1105 1106 return fp; 1107 } 1108 1109 static void bpf_prog_clone_free(struct bpf_prog *fp) 1110 { 1111 /* aux was stolen by the other clone, so we cannot free 1112 * it from this path! It will be freed eventually by the 1113 * other program on release. 1114 * 1115 * At this point, we don't need a deferred release since 1116 * clone is guaranteed to not be locked. 1117 */ 1118 fp->aux = NULL; 1119 __bpf_prog_free(fp); 1120 } 1121 1122 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1123 { 1124 /* We have to repoint aux->prog to self, as we don't 1125 * know whether fp here is the clone or the original. 1126 */ 1127 fp->aux->prog = fp; 1128 bpf_prog_clone_free(fp_other); 1129 } 1130 1131 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1132 { 1133 struct bpf_insn insn_buff[16], aux[2]; 1134 struct bpf_prog *clone, *tmp; 1135 int insn_delta, insn_cnt; 1136 struct bpf_insn *insn; 1137 int i, rewritten; 1138 1139 if (!bpf_jit_blinding_enabled(prog) || prog->blinded) 1140 return prog; 1141 1142 clone = bpf_prog_clone_create(prog, GFP_USER); 1143 if (!clone) 1144 return ERR_PTR(-ENOMEM); 1145 1146 insn_cnt = clone->len; 1147 insn = clone->insnsi; 1148 1149 for (i = 0; i < insn_cnt; i++, insn++) { 1150 /* We temporarily need to hold the original ld64 insn 1151 * so that we can still access the first part in the 1152 * second blinding run. 1153 */ 1154 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1155 insn[1].code == 0) 1156 memcpy(aux, insn, sizeof(aux)); 1157 1158 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1159 clone->aux->verifier_zext); 1160 if (!rewritten) 1161 continue; 1162 1163 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1164 if (IS_ERR(tmp)) { 1165 /* Patching may have repointed aux->prog during 1166 * realloc from the original one, so we need to 1167 * fix it up here on error. 1168 */ 1169 bpf_jit_prog_release_other(prog, clone); 1170 return tmp; 1171 } 1172 1173 clone = tmp; 1174 insn_delta = rewritten - 1; 1175 1176 /* Walk new program and skip insns we just inserted. */ 1177 insn = clone->insnsi + i + insn_delta; 1178 insn_cnt += insn_delta; 1179 i += insn_delta; 1180 } 1181 1182 clone->blinded = 1; 1183 return clone; 1184 } 1185 #endif /* CONFIG_BPF_JIT */ 1186 1187 /* Base function for offset calculation. Needs to go into .text section, 1188 * therefore keeping it non-static as well; will also be used by JITs 1189 * anyway later on, so do not let the compiler omit it. This also needs 1190 * to go into kallsyms for correlation from e.g. bpftool, so naming 1191 * must not change. 1192 */ 1193 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1194 { 1195 return 0; 1196 } 1197 EXPORT_SYMBOL_GPL(__bpf_call_base); 1198 1199 /* All UAPI available opcodes. */ 1200 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1201 /* 32 bit ALU operations. */ \ 1202 /* Register based. */ \ 1203 INSN_3(ALU, ADD, X), \ 1204 INSN_3(ALU, SUB, X), \ 1205 INSN_3(ALU, AND, X), \ 1206 INSN_3(ALU, OR, X), \ 1207 INSN_3(ALU, LSH, X), \ 1208 INSN_3(ALU, RSH, X), \ 1209 INSN_3(ALU, XOR, X), \ 1210 INSN_3(ALU, MUL, X), \ 1211 INSN_3(ALU, MOV, X), \ 1212 INSN_3(ALU, ARSH, X), \ 1213 INSN_3(ALU, DIV, X), \ 1214 INSN_3(ALU, MOD, X), \ 1215 INSN_2(ALU, NEG), \ 1216 INSN_3(ALU, END, TO_BE), \ 1217 INSN_3(ALU, END, TO_LE), \ 1218 /* Immediate based. */ \ 1219 INSN_3(ALU, ADD, K), \ 1220 INSN_3(ALU, SUB, K), \ 1221 INSN_3(ALU, AND, K), \ 1222 INSN_3(ALU, OR, K), \ 1223 INSN_3(ALU, LSH, K), \ 1224 INSN_3(ALU, RSH, K), \ 1225 INSN_3(ALU, XOR, K), \ 1226 INSN_3(ALU, MUL, K), \ 1227 INSN_3(ALU, MOV, K), \ 1228 INSN_3(ALU, ARSH, K), \ 1229 INSN_3(ALU, DIV, K), \ 1230 INSN_3(ALU, MOD, K), \ 1231 /* 64 bit ALU operations. */ \ 1232 /* Register based. */ \ 1233 INSN_3(ALU64, ADD, X), \ 1234 INSN_3(ALU64, SUB, X), \ 1235 INSN_3(ALU64, AND, X), \ 1236 INSN_3(ALU64, OR, X), \ 1237 INSN_3(ALU64, LSH, X), \ 1238 INSN_3(ALU64, RSH, X), \ 1239 INSN_3(ALU64, XOR, X), \ 1240 INSN_3(ALU64, MUL, X), \ 1241 INSN_3(ALU64, MOV, X), \ 1242 INSN_3(ALU64, ARSH, X), \ 1243 INSN_3(ALU64, DIV, X), \ 1244 INSN_3(ALU64, MOD, X), \ 1245 INSN_2(ALU64, NEG), \ 1246 /* Immediate based. */ \ 1247 INSN_3(ALU64, ADD, K), \ 1248 INSN_3(ALU64, SUB, K), \ 1249 INSN_3(ALU64, AND, K), \ 1250 INSN_3(ALU64, OR, K), \ 1251 INSN_3(ALU64, LSH, K), \ 1252 INSN_3(ALU64, RSH, K), \ 1253 INSN_3(ALU64, XOR, K), \ 1254 INSN_3(ALU64, MUL, K), \ 1255 INSN_3(ALU64, MOV, K), \ 1256 INSN_3(ALU64, ARSH, K), \ 1257 INSN_3(ALU64, DIV, K), \ 1258 INSN_3(ALU64, MOD, K), \ 1259 /* Call instruction. */ \ 1260 INSN_2(JMP, CALL), \ 1261 /* Exit instruction. */ \ 1262 INSN_2(JMP, EXIT), \ 1263 /* 32-bit Jump instructions. */ \ 1264 /* Register based. */ \ 1265 INSN_3(JMP32, JEQ, X), \ 1266 INSN_3(JMP32, JNE, X), \ 1267 INSN_3(JMP32, JGT, X), \ 1268 INSN_3(JMP32, JLT, X), \ 1269 INSN_3(JMP32, JGE, X), \ 1270 INSN_3(JMP32, JLE, X), \ 1271 INSN_3(JMP32, JSGT, X), \ 1272 INSN_3(JMP32, JSLT, X), \ 1273 INSN_3(JMP32, JSGE, X), \ 1274 INSN_3(JMP32, JSLE, X), \ 1275 INSN_3(JMP32, JSET, X), \ 1276 /* Immediate based. */ \ 1277 INSN_3(JMP32, JEQ, K), \ 1278 INSN_3(JMP32, JNE, K), \ 1279 INSN_3(JMP32, JGT, K), \ 1280 INSN_3(JMP32, JLT, K), \ 1281 INSN_3(JMP32, JGE, K), \ 1282 INSN_3(JMP32, JLE, K), \ 1283 INSN_3(JMP32, JSGT, K), \ 1284 INSN_3(JMP32, JSLT, K), \ 1285 INSN_3(JMP32, JSGE, K), \ 1286 INSN_3(JMP32, JSLE, K), \ 1287 INSN_3(JMP32, JSET, K), \ 1288 /* Jump instructions. */ \ 1289 /* Register based. */ \ 1290 INSN_3(JMP, JEQ, X), \ 1291 INSN_3(JMP, JNE, X), \ 1292 INSN_3(JMP, JGT, X), \ 1293 INSN_3(JMP, JLT, X), \ 1294 INSN_3(JMP, JGE, X), \ 1295 INSN_3(JMP, JLE, X), \ 1296 INSN_3(JMP, JSGT, X), \ 1297 INSN_3(JMP, JSLT, X), \ 1298 INSN_3(JMP, JSGE, X), \ 1299 INSN_3(JMP, JSLE, X), \ 1300 INSN_3(JMP, JSET, X), \ 1301 /* Immediate based. */ \ 1302 INSN_3(JMP, JEQ, K), \ 1303 INSN_3(JMP, JNE, K), \ 1304 INSN_3(JMP, JGT, K), \ 1305 INSN_3(JMP, JLT, K), \ 1306 INSN_3(JMP, JGE, K), \ 1307 INSN_3(JMP, JLE, K), \ 1308 INSN_3(JMP, JSGT, K), \ 1309 INSN_3(JMP, JSLT, K), \ 1310 INSN_3(JMP, JSGE, K), \ 1311 INSN_3(JMP, JSLE, K), \ 1312 INSN_3(JMP, JSET, K), \ 1313 INSN_2(JMP, JA), \ 1314 /* Store instructions. */ \ 1315 /* Register based. */ \ 1316 INSN_3(STX, MEM, B), \ 1317 INSN_3(STX, MEM, H), \ 1318 INSN_3(STX, MEM, W), \ 1319 INSN_3(STX, MEM, DW), \ 1320 INSN_3(STX, XADD, W), \ 1321 INSN_3(STX, XADD, DW), \ 1322 /* Immediate based. */ \ 1323 INSN_3(ST, MEM, B), \ 1324 INSN_3(ST, MEM, H), \ 1325 INSN_3(ST, MEM, W), \ 1326 INSN_3(ST, MEM, DW), \ 1327 /* Load instructions. */ \ 1328 /* Register based. */ \ 1329 INSN_3(LDX, MEM, B), \ 1330 INSN_3(LDX, MEM, H), \ 1331 INSN_3(LDX, MEM, W), \ 1332 INSN_3(LDX, MEM, DW), \ 1333 /* Immediate based. */ \ 1334 INSN_3(LD, IMM, DW) 1335 1336 bool bpf_opcode_in_insntable(u8 code) 1337 { 1338 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1339 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1340 static const bool public_insntable[256] = { 1341 [0 ... 255] = false, 1342 /* Now overwrite non-defaults ... */ 1343 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1344 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1345 [BPF_LD | BPF_ABS | BPF_B] = true, 1346 [BPF_LD | BPF_ABS | BPF_H] = true, 1347 [BPF_LD | BPF_ABS | BPF_W] = true, 1348 [BPF_LD | BPF_IND | BPF_B] = true, 1349 [BPF_LD | BPF_IND | BPF_H] = true, 1350 [BPF_LD | BPF_IND | BPF_W] = true, 1351 }; 1352 #undef BPF_INSN_3_TBL 1353 #undef BPF_INSN_2_TBL 1354 return public_insntable[code]; 1355 } 1356 1357 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1358 u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) 1359 { 1360 memset(dst, 0, size); 1361 return -EFAULT; 1362 } 1363 1364 /** 1365 * __bpf_prog_run - run eBPF program on a given context 1366 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1367 * @insn: is the array of eBPF instructions 1368 * @stack: is the eBPF storage stack 1369 * 1370 * Decode and execute eBPF instructions. 1371 */ 1372 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack) 1373 { 1374 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1375 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1376 static const void * const jumptable[256] __annotate_jump_table = { 1377 [0 ... 255] = &&default_label, 1378 /* Now overwrite non-defaults ... */ 1379 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1380 /* Non-UAPI available opcodes. */ 1381 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1382 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1383 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1384 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1385 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1386 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1387 }; 1388 #undef BPF_INSN_3_LBL 1389 #undef BPF_INSN_2_LBL 1390 u32 tail_call_cnt = 0; 1391 1392 #define CONT ({ insn++; goto select_insn; }) 1393 #define CONT_JMP ({ insn++; goto select_insn; }) 1394 1395 select_insn: 1396 goto *jumptable[insn->code]; 1397 1398 /* ALU */ 1399 #define ALU(OPCODE, OP) \ 1400 ALU64_##OPCODE##_X: \ 1401 DST = DST OP SRC; \ 1402 CONT; \ 1403 ALU_##OPCODE##_X: \ 1404 DST = (u32) DST OP (u32) SRC; \ 1405 CONT; \ 1406 ALU64_##OPCODE##_K: \ 1407 DST = DST OP IMM; \ 1408 CONT; \ 1409 ALU_##OPCODE##_K: \ 1410 DST = (u32) DST OP (u32) IMM; \ 1411 CONT; 1412 1413 ALU(ADD, +) 1414 ALU(SUB, -) 1415 ALU(AND, &) 1416 ALU(OR, |) 1417 ALU(LSH, <<) 1418 ALU(RSH, >>) 1419 ALU(XOR, ^) 1420 ALU(MUL, *) 1421 #undef ALU 1422 ALU_NEG: 1423 DST = (u32) -DST; 1424 CONT; 1425 ALU64_NEG: 1426 DST = -DST; 1427 CONT; 1428 ALU_MOV_X: 1429 DST = (u32) SRC; 1430 CONT; 1431 ALU_MOV_K: 1432 DST = (u32) IMM; 1433 CONT; 1434 ALU64_MOV_X: 1435 DST = SRC; 1436 CONT; 1437 ALU64_MOV_K: 1438 DST = IMM; 1439 CONT; 1440 LD_IMM_DW: 1441 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1442 insn++; 1443 CONT; 1444 ALU_ARSH_X: 1445 DST = (u64) (u32) (((s32) DST) >> SRC); 1446 CONT; 1447 ALU_ARSH_K: 1448 DST = (u64) (u32) (((s32) DST) >> IMM); 1449 CONT; 1450 ALU64_ARSH_X: 1451 (*(s64 *) &DST) >>= SRC; 1452 CONT; 1453 ALU64_ARSH_K: 1454 (*(s64 *) &DST) >>= IMM; 1455 CONT; 1456 ALU64_MOD_X: 1457 div64_u64_rem(DST, SRC, &AX); 1458 DST = AX; 1459 CONT; 1460 ALU_MOD_X: 1461 AX = (u32) DST; 1462 DST = do_div(AX, (u32) SRC); 1463 CONT; 1464 ALU64_MOD_K: 1465 div64_u64_rem(DST, IMM, &AX); 1466 DST = AX; 1467 CONT; 1468 ALU_MOD_K: 1469 AX = (u32) DST; 1470 DST = do_div(AX, (u32) IMM); 1471 CONT; 1472 ALU64_DIV_X: 1473 DST = div64_u64(DST, SRC); 1474 CONT; 1475 ALU_DIV_X: 1476 AX = (u32) DST; 1477 do_div(AX, (u32) SRC); 1478 DST = (u32) AX; 1479 CONT; 1480 ALU64_DIV_K: 1481 DST = div64_u64(DST, IMM); 1482 CONT; 1483 ALU_DIV_K: 1484 AX = (u32) DST; 1485 do_div(AX, (u32) IMM); 1486 DST = (u32) AX; 1487 CONT; 1488 ALU_END_TO_BE: 1489 switch (IMM) { 1490 case 16: 1491 DST = (__force u16) cpu_to_be16(DST); 1492 break; 1493 case 32: 1494 DST = (__force u32) cpu_to_be32(DST); 1495 break; 1496 case 64: 1497 DST = (__force u64) cpu_to_be64(DST); 1498 break; 1499 } 1500 CONT; 1501 ALU_END_TO_LE: 1502 switch (IMM) { 1503 case 16: 1504 DST = (__force u16) cpu_to_le16(DST); 1505 break; 1506 case 32: 1507 DST = (__force u32) cpu_to_le32(DST); 1508 break; 1509 case 64: 1510 DST = (__force u64) cpu_to_le64(DST); 1511 break; 1512 } 1513 CONT; 1514 1515 /* CALL */ 1516 JMP_CALL: 1517 /* Function call scratches BPF_R1-BPF_R5 registers, 1518 * preserves BPF_R6-BPF_R9, and stores return value 1519 * into BPF_R0. 1520 */ 1521 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1522 BPF_R4, BPF_R5); 1523 CONT; 1524 1525 JMP_CALL_ARGS: 1526 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 1527 BPF_R3, BPF_R4, 1528 BPF_R5, 1529 insn + insn->off + 1); 1530 CONT; 1531 1532 JMP_TAIL_CALL: { 1533 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1534 struct bpf_array *array = container_of(map, struct bpf_array, map); 1535 struct bpf_prog *prog; 1536 u32 index = BPF_R3; 1537 1538 if (unlikely(index >= array->map.max_entries)) 1539 goto out; 1540 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) 1541 goto out; 1542 1543 tail_call_cnt++; 1544 1545 prog = READ_ONCE(array->ptrs[index]); 1546 if (!prog) 1547 goto out; 1548 1549 /* ARG1 at this point is guaranteed to point to CTX from 1550 * the verifier side due to the fact that the tail call is 1551 * handled like a helper, that is, bpf_tail_call_proto, 1552 * where arg1_type is ARG_PTR_TO_CTX. 1553 */ 1554 insn = prog->insnsi; 1555 goto select_insn; 1556 out: 1557 CONT; 1558 } 1559 JMP_JA: 1560 insn += insn->off; 1561 CONT; 1562 JMP_EXIT: 1563 return BPF_R0; 1564 /* JMP */ 1565 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 1566 JMP_##OPCODE##_X: \ 1567 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 1568 insn += insn->off; \ 1569 CONT_JMP; \ 1570 } \ 1571 CONT; \ 1572 JMP32_##OPCODE##_X: \ 1573 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 1574 insn += insn->off; \ 1575 CONT_JMP; \ 1576 } \ 1577 CONT; \ 1578 JMP_##OPCODE##_K: \ 1579 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 1580 insn += insn->off; \ 1581 CONT_JMP; \ 1582 } \ 1583 CONT; \ 1584 JMP32_##OPCODE##_K: \ 1585 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 1586 insn += insn->off; \ 1587 CONT_JMP; \ 1588 } \ 1589 CONT; 1590 COND_JMP(u, JEQ, ==) 1591 COND_JMP(u, JNE, !=) 1592 COND_JMP(u, JGT, >) 1593 COND_JMP(u, JLT, <) 1594 COND_JMP(u, JGE, >=) 1595 COND_JMP(u, JLE, <=) 1596 COND_JMP(u, JSET, &) 1597 COND_JMP(s, JSGT, >) 1598 COND_JMP(s, JSLT, <) 1599 COND_JMP(s, JSGE, >=) 1600 COND_JMP(s, JSLE, <=) 1601 #undef COND_JMP 1602 /* STX and ST and LDX*/ 1603 #define LDST(SIZEOP, SIZE) \ 1604 STX_MEM_##SIZEOP: \ 1605 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 1606 CONT; \ 1607 ST_MEM_##SIZEOP: \ 1608 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 1609 CONT; \ 1610 LDX_MEM_##SIZEOP: \ 1611 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 1612 CONT; 1613 1614 LDST(B, u8) 1615 LDST(H, u16) 1616 LDST(W, u32) 1617 LDST(DW, u64) 1618 #undef LDST 1619 #define LDX_PROBE(SIZEOP, SIZE) \ 1620 LDX_PROBE_MEM_##SIZEOP: \ 1621 bpf_probe_read_kernel(&DST, SIZE, (const void *)(long) (SRC + insn->off)); \ 1622 CONT; 1623 LDX_PROBE(B, 1) 1624 LDX_PROBE(H, 2) 1625 LDX_PROBE(W, 4) 1626 LDX_PROBE(DW, 8) 1627 #undef LDX_PROBE 1628 1629 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */ 1630 atomic_add((u32) SRC, (atomic_t *)(unsigned long) 1631 (DST + insn->off)); 1632 CONT; 1633 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */ 1634 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long) 1635 (DST + insn->off)); 1636 CONT; 1637 1638 default_label: 1639 /* If we ever reach this, we have a bug somewhere. Die hard here 1640 * instead of just returning 0; we could be somewhere in a subprog, 1641 * so execution could continue otherwise which we do /not/ want. 1642 * 1643 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 1644 */ 1645 pr_warn("BPF interpreter: unknown opcode %02x\n", insn->code); 1646 BUG_ON(1); 1647 return 0; 1648 } 1649 1650 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 1651 #define DEFINE_BPF_PROG_RUN(stack_size) \ 1652 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 1653 { \ 1654 u64 stack[stack_size / sizeof(u64)]; \ 1655 u64 regs[MAX_BPF_EXT_REG]; \ 1656 \ 1657 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 1658 ARG1 = (u64) (unsigned long) ctx; \ 1659 return ___bpf_prog_run(regs, insn, stack); \ 1660 } 1661 1662 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 1663 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 1664 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 1665 const struct bpf_insn *insn) \ 1666 { \ 1667 u64 stack[stack_size / sizeof(u64)]; \ 1668 u64 regs[MAX_BPF_EXT_REG]; \ 1669 \ 1670 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 1671 BPF_R1 = r1; \ 1672 BPF_R2 = r2; \ 1673 BPF_R3 = r3; \ 1674 BPF_R4 = r4; \ 1675 BPF_R5 = r5; \ 1676 return ___bpf_prog_run(regs, insn, stack); \ 1677 } 1678 1679 #define EVAL1(FN, X) FN(X) 1680 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 1681 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 1682 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 1683 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 1684 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 1685 1686 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 1687 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 1688 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 1689 1690 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 1691 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 1692 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 1693 1694 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 1695 1696 static unsigned int (*interpreters[])(const void *ctx, 1697 const struct bpf_insn *insn) = { 1698 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 1699 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 1700 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 1701 }; 1702 #undef PROG_NAME_LIST 1703 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 1704 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 1705 const struct bpf_insn *insn) = { 1706 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 1707 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 1708 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 1709 }; 1710 #undef PROG_NAME_LIST 1711 1712 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 1713 { 1714 stack_depth = max_t(u32, stack_depth, 1); 1715 insn->off = (s16) insn->imm; 1716 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 1717 __bpf_call_base_args; 1718 insn->code = BPF_JMP | BPF_CALL_ARGS; 1719 } 1720 1721 #else 1722 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 1723 const struct bpf_insn *insn) 1724 { 1725 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 1726 * is not working properly, so warn about it! 1727 */ 1728 WARN_ON_ONCE(1); 1729 return 0; 1730 } 1731 #endif 1732 1733 bool bpf_prog_array_compatible(struct bpf_array *array, 1734 const struct bpf_prog *fp) 1735 { 1736 if (fp->kprobe_override) 1737 return false; 1738 1739 if (!array->aux->type) { 1740 /* There's no owner yet where we could check for 1741 * compatibility. 1742 */ 1743 array->aux->type = fp->type; 1744 array->aux->jited = fp->jited; 1745 return true; 1746 } 1747 1748 return array->aux->type == fp->type && 1749 array->aux->jited == fp->jited; 1750 } 1751 1752 static int bpf_check_tail_call(const struct bpf_prog *fp) 1753 { 1754 struct bpf_prog_aux *aux = fp->aux; 1755 int i, ret = 0; 1756 1757 mutex_lock(&aux->used_maps_mutex); 1758 for (i = 0; i < aux->used_map_cnt; i++) { 1759 struct bpf_map *map = aux->used_maps[i]; 1760 struct bpf_array *array; 1761 1762 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) 1763 continue; 1764 1765 array = container_of(map, struct bpf_array, map); 1766 if (!bpf_prog_array_compatible(array, fp)) { 1767 ret = -EINVAL; 1768 goto out; 1769 } 1770 } 1771 1772 out: 1773 mutex_unlock(&aux->used_maps_mutex); 1774 return ret; 1775 } 1776 1777 static void bpf_prog_select_func(struct bpf_prog *fp) 1778 { 1779 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1780 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 1781 1782 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 1783 #else 1784 fp->bpf_func = __bpf_prog_ret0_warn; 1785 #endif 1786 } 1787 1788 /** 1789 * bpf_prog_select_runtime - select exec runtime for BPF program 1790 * @fp: bpf_prog populated with internal BPF program 1791 * @err: pointer to error variable 1792 * 1793 * Try to JIT eBPF program, if JIT is not available, use interpreter. 1794 * The BPF program will be executed via BPF_PROG_RUN() macro. 1795 */ 1796 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 1797 { 1798 /* In case of BPF to BPF calls, verifier did all the prep 1799 * work with regards to JITing, etc. 1800 */ 1801 if (fp->bpf_func) 1802 goto finalize; 1803 1804 bpf_prog_select_func(fp); 1805 1806 /* eBPF JITs can rewrite the program in case constant 1807 * blinding is active. However, in case of error during 1808 * blinding, bpf_int_jit_compile() must always return a 1809 * valid program, which in this case would simply not 1810 * be JITed, but falls back to the interpreter. 1811 */ 1812 if (!bpf_prog_is_dev_bound(fp->aux)) { 1813 *err = bpf_prog_alloc_jited_linfo(fp); 1814 if (*err) 1815 return fp; 1816 1817 fp = bpf_int_jit_compile(fp); 1818 if (!fp->jited) { 1819 bpf_prog_free_jited_linfo(fp); 1820 #ifdef CONFIG_BPF_JIT_ALWAYS_ON 1821 *err = -ENOTSUPP; 1822 return fp; 1823 #endif 1824 } else { 1825 bpf_prog_free_unused_jited_linfo(fp); 1826 } 1827 } else { 1828 *err = bpf_prog_offload_compile(fp); 1829 if (*err) 1830 return fp; 1831 } 1832 1833 finalize: 1834 bpf_prog_lock_ro(fp); 1835 1836 /* The tail call compatibility check can only be done at 1837 * this late stage as we need to determine, if we deal 1838 * with JITed or non JITed program concatenations and not 1839 * all eBPF JITs might immediately support all features. 1840 */ 1841 *err = bpf_check_tail_call(fp); 1842 1843 return fp; 1844 } 1845 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 1846 1847 static unsigned int __bpf_prog_ret1(const void *ctx, 1848 const struct bpf_insn *insn) 1849 { 1850 return 1; 1851 } 1852 1853 static struct bpf_prog_dummy { 1854 struct bpf_prog prog; 1855 } dummy_bpf_prog = { 1856 .prog = { 1857 .bpf_func = __bpf_prog_ret1, 1858 }, 1859 }; 1860 1861 /* to avoid allocating empty bpf_prog_array for cgroups that 1862 * don't have bpf program attached use one global 'empty_prog_array' 1863 * It will not be modified the caller of bpf_prog_array_alloc() 1864 * (since caller requested prog_cnt == 0) 1865 * that pointer should be 'freed' by bpf_prog_array_free() 1866 */ 1867 static struct { 1868 struct bpf_prog_array hdr; 1869 struct bpf_prog *null_prog; 1870 } empty_prog_array = { 1871 .null_prog = NULL, 1872 }; 1873 1874 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 1875 { 1876 if (prog_cnt) 1877 return kzalloc(sizeof(struct bpf_prog_array) + 1878 sizeof(struct bpf_prog_array_item) * 1879 (prog_cnt + 1), 1880 flags); 1881 1882 return &empty_prog_array.hdr; 1883 } 1884 1885 void bpf_prog_array_free(struct bpf_prog_array *progs) 1886 { 1887 if (!progs || progs == &empty_prog_array.hdr) 1888 return; 1889 kfree_rcu(progs, rcu); 1890 } 1891 1892 int bpf_prog_array_length(struct bpf_prog_array *array) 1893 { 1894 struct bpf_prog_array_item *item; 1895 u32 cnt = 0; 1896 1897 for (item = array->items; item->prog; item++) 1898 if (item->prog != &dummy_bpf_prog.prog) 1899 cnt++; 1900 return cnt; 1901 } 1902 1903 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 1904 { 1905 struct bpf_prog_array_item *item; 1906 1907 for (item = array->items; item->prog; item++) 1908 if (item->prog != &dummy_bpf_prog.prog) 1909 return false; 1910 return true; 1911 } 1912 1913 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 1914 u32 *prog_ids, 1915 u32 request_cnt) 1916 { 1917 struct bpf_prog_array_item *item; 1918 int i = 0; 1919 1920 for (item = array->items; item->prog; item++) { 1921 if (item->prog == &dummy_bpf_prog.prog) 1922 continue; 1923 prog_ids[i] = item->prog->aux->id; 1924 if (++i == request_cnt) { 1925 item++; 1926 break; 1927 } 1928 } 1929 1930 return !!(item->prog); 1931 } 1932 1933 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 1934 __u32 __user *prog_ids, u32 cnt) 1935 { 1936 unsigned long err = 0; 1937 bool nospc; 1938 u32 *ids; 1939 1940 /* users of this function are doing: 1941 * cnt = bpf_prog_array_length(); 1942 * if (cnt > 0) 1943 * bpf_prog_array_copy_to_user(..., cnt); 1944 * so below kcalloc doesn't need extra cnt > 0 check. 1945 */ 1946 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 1947 if (!ids) 1948 return -ENOMEM; 1949 nospc = bpf_prog_array_copy_core(array, ids, cnt); 1950 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 1951 kfree(ids); 1952 if (err) 1953 return -EFAULT; 1954 if (nospc) 1955 return -ENOSPC; 1956 return 0; 1957 } 1958 1959 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 1960 struct bpf_prog *old_prog) 1961 { 1962 struct bpf_prog_array_item *item; 1963 1964 for (item = array->items; item->prog; item++) 1965 if (item->prog == old_prog) { 1966 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 1967 break; 1968 } 1969 } 1970 1971 /** 1972 * bpf_prog_array_delete_safe_at() - Replaces the program at the given 1973 * index into the program array with 1974 * a dummy no-op program. 1975 * @array: a bpf_prog_array 1976 * @index: the index of the program to replace 1977 * 1978 * Skips over dummy programs, by not counting them, when calculating 1979 * the position of the program to replace. 1980 * 1981 * Return: 1982 * * 0 - Success 1983 * * -EINVAL - Invalid index value. Must be a non-negative integer. 1984 * * -ENOENT - Index out of range 1985 */ 1986 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) 1987 { 1988 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); 1989 } 1990 1991 /** 1992 * bpf_prog_array_update_at() - Updates the program at the given index 1993 * into the program array. 1994 * @array: a bpf_prog_array 1995 * @index: the index of the program to update 1996 * @prog: the program to insert into the array 1997 * 1998 * Skips over dummy programs, by not counting them, when calculating 1999 * the position of the program to update. 2000 * 2001 * Return: 2002 * * 0 - Success 2003 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2004 * * -ENOENT - Index out of range 2005 */ 2006 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, 2007 struct bpf_prog *prog) 2008 { 2009 struct bpf_prog_array_item *item; 2010 2011 if (unlikely(index < 0)) 2012 return -EINVAL; 2013 2014 for (item = array->items; item->prog; item++) { 2015 if (item->prog == &dummy_bpf_prog.prog) 2016 continue; 2017 if (!index) { 2018 WRITE_ONCE(item->prog, prog); 2019 return 0; 2020 } 2021 index--; 2022 } 2023 return -ENOENT; 2024 } 2025 2026 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 2027 struct bpf_prog *exclude_prog, 2028 struct bpf_prog *include_prog, 2029 struct bpf_prog_array **new_array) 2030 { 2031 int new_prog_cnt, carry_prog_cnt = 0; 2032 struct bpf_prog_array_item *existing; 2033 struct bpf_prog_array *array; 2034 bool found_exclude = false; 2035 int new_prog_idx = 0; 2036 2037 /* Figure out how many existing progs we need to carry over to 2038 * the new array. 2039 */ 2040 if (old_array) { 2041 existing = old_array->items; 2042 for (; existing->prog; existing++) { 2043 if (existing->prog == exclude_prog) { 2044 found_exclude = true; 2045 continue; 2046 } 2047 if (existing->prog != &dummy_bpf_prog.prog) 2048 carry_prog_cnt++; 2049 if (existing->prog == include_prog) 2050 return -EEXIST; 2051 } 2052 } 2053 2054 if (exclude_prog && !found_exclude) 2055 return -ENOENT; 2056 2057 /* How many progs (not NULL) will be in the new array? */ 2058 new_prog_cnt = carry_prog_cnt; 2059 if (include_prog) 2060 new_prog_cnt += 1; 2061 2062 /* Do we have any prog (not NULL) in the new array? */ 2063 if (!new_prog_cnt) { 2064 *new_array = NULL; 2065 return 0; 2066 } 2067 2068 /* +1 as the end of prog_array is marked with NULL */ 2069 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2070 if (!array) 2071 return -ENOMEM; 2072 2073 /* Fill in the new prog array */ 2074 if (carry_prog_cnt) { 2075 existing = old_array->items; 2076 for (; existing->prog; existing++) 2077 if (existing->prog != exclude_prog && 2078 existing->prog != &dummy_bpf_prog.prog) { 2079 array->items[new_prog_idx++].prog = 2080 existing->prog; 2081 } 2082 } 2083 if (include_prog) 2084 array->items[new_prog_idx++].prog = include_prog; 2085 array->items[new_prog_idx].prog = NULL; 2086 *new_array = array; 2087 return 0; 2088 } 2089 2090 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2091 u32 *prog_ids, u32 request_cnt, 2092 u32 *prog_cnt) 2093 { 2094 u32 cnt = 0; 2095 2096 if (array) 2097 cnt = bpf_prog_array_length(array); 2098 2099 *prog_cnt = cnt; 2100 2101 /* return early if user requested only program count or nothing to copy */ 2102 if (!request_cnt || !cnt) 2103 return 0; 2104 2105 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2106 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2107 : 0; 2108 } 2109 2110 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2111 struct bpf_map **used_maps, u32 len) 2112 { 2113 struct bpf_map *map; 2114 u32 i; 2115 2116 for (i = 0; i < len; i++) { 2117 map = used_maps[i]; 2118 if (map->ops->map_poke_untrack) 2119 map->ops->map_poke_untrack(map, aux); 2120 bpf_map_put(map); 2121 } 2122 } 2123 2124 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2125 { 2126 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2127 kfree(aux->used_maps); 2128 } 2129 2130 static void bpf_prog_free_deferred(struct work_struct *work) 2131 { 2132 struct bpf_prog_aux *aux; 2133 int i; 2134 2135 aux = container_of(work, struct bpf_prog_aux, work); 2136 bpf_free_used_maps(aux); 2137 if (bpf_prog_is_dev_bound(aux)) 2138 bpf_prog_offload_destroy(aux->prog); 2139 #ifdef CONFIG_PERF_EVENTS 2140 if (aux->prog->has_callchain_buf) 2141 put_callchain_buffers(); 2142 #endif 2143 if (aux->dst_trampoline) 2144 bpf_trampoline_put(aux->dst_trampoline); 2145 for (i = 0; i < aux->func_cnt; i++) 2146 bpf_jit_free(aux->func[i]); 2147 if (aux->func_cnt) { 2148 kfree(aux->func); 2149 bpf_prog_unlock_free(aux->prog); 2150 } else { 2151 bpf_jit_free(aux->prog); 2152 } 2153 } 2154 2155 /* Free internal BPF program */ 2156 void bpf_prog_free(struct bpf_prog *fp) 2157 { 2158 struct bpf_prog_aux *aux = fp->aux; 2159 2160 if (aux->dst_prog) 2161 bpf_prog_put(aux->dst_prog); 2162 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2163 schedule_work(&aux->work); 2164 } 2165 EXPORT_SYMBOL_GPL(bpf_prog_free); 2166 2167 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 2168 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2169 2170 void bpf_user_rnd_init_once(void) 2171 { 2172 prandom_init_once(&bpf_user_rnd_state); 2173 } 2174 2175 BPF_CALL_0(bpf_user_rnd_u32) 2176 { 2177 /* Should someone ever have the rather unwise idea to use some 2178 * of the registers passed into this function, then note that 2179 * this function is called from native eBPF and classic-to-eBPF 2180 * transformations. Register assignments from both sides are 2181 * different, f.e. classic always sets fn(ctx, A, X) here. 2182 */ 2183 struct rnd_state *state; 2184 u32 res; 2185 2186 state = &get_cpu_var(bpf_user_rnd_state); 2187 res = prandom_u32_state(state); 2188 put_cpu_var(bpf_user_rnd_state); 2189 2190 return res; 2191 } 2192 2193 BPF_CALL_0(bpf_get_raw_cpu_id) 2194 { 2195 return raw_smp_processor_id(); 2196 } 2197 2198 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2199 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2200 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2201 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2202 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2203 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2204 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2205 const struct bpf_func_proto bpf_spin_lock_proto __weak; 2206 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 2207 const struct bpf_func_proto bpf_jiffies64_proto __weak; 2208 2209 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2210 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2211 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2212 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2213 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 2214 2215 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2216 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2217 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2218 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2219 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 2220 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2221 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 2222 const struct bpf_func_proto bpf_snprintf_btf_proto __weak; 2223 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; 2224 2225 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2226 { 2227 return NULL; 2228 } 2229 2230 u64 __weak 2231 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2232 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2233 { 2234 return -ENOTSUPP; 2235 } 2236 EXPORT_SYMBOL_GPL(bpf_event_output); 2237 2238 /* Always built-in helper functions. */ 2239 const struct bpf_func_proto bpf_tail_call_proto = { 2240 .func = NULL, 2241 .gpl_only = false, 2242 .ret_type = RET_VOID, 2243 .arg1_type = ARG_PTR_TO_CTX, 2244 .arg2_type = ARG_CONST_MAP_PTR, 2245 .arg3_type = ARG_ANYTHING, 2246 }; 2247 2248 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 2249 * It is encouraged to implement bpf_int_jit_compile() instead, so that 2250 * eBPF and implicitly also cBPF can get JITed! 2251 */ 2252 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 2253 { 2254 return prog; 2255 } 2256 2257 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 2258 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 2259 */ 2260 void __weak bpf_jit_compile(struct bpf_prog *prog) 2261 { 2262 } 2263 2264 bool __weak bpf_helper_changes_pkt_data(void *func) 2265 { 2266 return false; 2267 } 2268 2269 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 2270 * analysis code and wants explicit zero extension inserted by verifier. 2271 * Otherwise, return FALSE. 2272 */ 2273 bool __weak bpf_jit_needs_zext(void) 2274 { 2275 return false; 2276 } 2277 2278 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 2279 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 2280 */ 2281 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 2282 int len) 2283 { 2284 return -EFAULT; 2285 } 2286 2287 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, 2288 void *addr1, void *addr2) 2289 { 2290 return -ENOTSUPP; 2291 } 2292 2293 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 2294 EXPORT_SYMBOL(bpf_stats_enabled_key); 2295 2296 /* All definitions of tracepoints related to BPF. */ 2297 #define CREATE_TRACE_POINTS 2298 #include <linux/bpf_trace.h> 2299 2300 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 2301 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 2302