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 <linux/bpf_verifier.h> 36 #include <linux/nodemask.h> 37 38 #include <asm/barrier.h> 39 #include <asm/unaligned.h> 40 41 /* Registers */ 42 #define BPF_R0 regs[BPF_REG_0] 43 #define BPF_R1 regs[BPF_REG_1] 44 #define BPF_R2 regs[BPF_REG_2] 45 #define BPF_R3 regs[BPF_REG_3] 46 #define BPF_R4 regs[BPF_REG_4] 47 #define BPF_R5 regs[BPF_REG_5] 48 #define BPF_R6 regs[BPF_REG_6] 49 #define BPF_R7 regs[BPF_REG_7] 50 #define BPF_R8 regs[BPF_REG_8] 51 #define BPF_R9 regs[BPF_REG_9] 52 #define BPF_R10 regs[BPF_REG_10] 53 54 /* Named registers */ 55 #define DST regs[insn->dst_reg] 56 #define SRC regs[insn->src_reg] 57 #define FP regs[BPF_REG_FP] 58 #define AX regs[BPF_REG_AX] 59 #define ARG1 regs[BPF_REG_ARG1] 60 #define CTX regs[BPF_REG_CTX] 61 #define IMM insn->imm 62 63 /* No hurry in this branch 64 * 65 * Exported for the bpf jit load helper. 66 */ 67 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 68 { 69 u8 *ptr = NULL; 70 71 if (k >= SKF_NET_OFF) { 72 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 73 } else if (k >= SKF_LL_OFF) { 74 if (unlikely(!skb_mac_header_was_set(skb))) 75 return NULL; 76 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 77 } 78 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 79 return ptr; 80 81 return NULL; 82 } 83 84 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags) 85 { 86 gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; 87 struct bpf_prog_aux *aux; 88 struct bpf_prog *fp; 89 90 size = round_up(size, PAGE_SIZE); 91 fp = __vmalloc(size, gfp_flags); 92 if (fp == NULL) 93 return NULL; 94 95 aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT | gfp_extra_flags); 96 if (aux == NULL) { 97 vfree(fp); 98 return NULL; 99 } 100 fp->active = alloc_percpu_gfp(int, GFP_KERNEL_ACCOUNT | gfp_extra_flags); 101 if (!fp->active) { 102 vfree(fp); 103 kfree(aux); 104 return NULL; 105 } 106 107 fp->pages = size / PAGE_SIZE; 108 fp->aux = aux; 109 fp->aux->prog = fp; 110 fp->jit_requested = ebpf_jit_enabled(); 111 fp->blinding_requested = bpf_jit_blinding_enabled(fp); 112 #ifdef CONFIG_CGROUP_BPF 113 aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID; 114 #endif 115 116 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); 117 mutex_init(&fp->aux->used_maps_mutex); 118 mutex_init(&fp->aux->dst_mutex); 119 120 return fp; 121 } 122 123 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 124 { 125 gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; 126 struct bpf_prog *prog; 127 int cpu; 128 129 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); 130 if (!prog) 131 return NULL; 132 133 prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); 134 if (!prog->stats) { 135 free_percpu(prog->active); 136 kfree(prog->aux); 137 vfree(prog); 138 return NULL; 139 } 140 141 for_each_possible_cpu(cpu) { 142 struct bpf_prog_stats *pstats; 143 144 pstats = per_cpu_ptr(prog->stats, cpu); 145 u64_stats_init(&pstats->syncp); 146 } 147 return prog; 148 } 149 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 150 151 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 152 { 153 if (!prog->aux->nr_linfo || !prog->jit_requested) 154 return 0; 155 156 prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo, 157 sizeof(*prog->aux->jited_linfo), 158 GFP_KERNEL_ACCOUNT | __GFP_NOWARN); 159 if (!prog->aux->jited_linfo) 160 return -ENOMEM; 161 162 return 0; 163 } 164 165 void bpf_prog_jit_attempt_done(struct bpf_prog *prog) 166 { 167 if (prog->aux->jited_linfo && 168 (!prog->jited || !prog->aux->jited_linfo[0])) { 169 kvfree(prog->aux->jited_linfo); 170 prog->aux->jited_linfo = NULL; 171 } 172 173 kfree(prog->aux->kfunc_tab); 174 prog->aux->kfunc_tab = NULL; 175 } 176 177 /* The jit engine is responsible to provide an array 178 * for insn_off to the jited_off mapping (insn_to_jit_off). 179 * 180 * The idx to this array is the insn_off. Hence, the insn_off 181 * here is relative to the prog itself instead of the main prog. 182 * This array has one entry for each xlated bpf insn. 183 * 184 * jited_off is the byte off to the end of the jited insn. 185 * 186 * Hence, with 187 * insn_start: 188 * The first bpf insn off of the prog. The insn off 189 * here is relative to the main prog. 190 * e.g. if prog is a subprog, insn_start > 0 191 * linfo_idx: 192 * The prog's idx to prog->aux->linfo and jited_linfo 193 * 194 * jited_linfo[linfo_idx] = prog->bpf_func 195 * 196 * For i > linfo_idx, 197 * 198 * jited_linfo[i] = prog->bpf_func + 199 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 200 */ 201 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 202 const u32 *insn_to_jit_off) 203 { 204 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 205 const struct bpf_line_info *linfo; 206 void **jited_linfo; 207 208 if (!prog->aux->jited_linfo) 209 /* Userspace did not provide linfo */ 210 return; 211 212 linfo_idx = prog->aux->linfo_idx; 213 linfo = &prog->aux->linfo[linfo_idx]; 214 insn_start = linfo[0].insn_off; 215 insn_end = insn_start + prog->len; 216 217 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 218 jited_linfo[0] = prog->bpf_func; 219 220 nr_linfo = prog->aux->nr_linfo - linfo_idx; 221 222 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 223 /* The verifier ensures that linfo[i].insn_off is 224 * strictly increasing 225 */ 226 jited_linfo[i] = prog->bpf_func + 227 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 228 } 229 230 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 231 gfp_t gfp_extra_flags) 232 { 233 gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; 234 struct bpf_prog *fp; 235 u32 pages; 236 237 size = round_up(size, PAGE_SIZE); 238 pages = size / PAGE_SIZE; 239 if (pages <= fp_old->pages) 240 return fp_old; 241 242 fp = __vmalloc(size, gfp_flags); 243 if (fp) { 244 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 245 fp->pages = pages; 246 fp->aux->prog = fp; 247 248 /* We keep fp->aux from fp_old around in the new 249 * reallocated structure. 250 */ 251 fp_old->aux = NULL; 252 fp_old->stats = NULL; 253 fp_old->active = NULL; 254 __bpf_prog_free(fp_old); 255 } 256 257 return fp; 258 } 259 260 void __bpf_prog_free(struct bpf_prog *fp) 261 { 262 if (fp->aux) { 263 mutex_destroy(&fp->aux->used_maps_mutex); 264 mutex_destroy(&fp->aux->dst_mutex); 265 kfree(fp->aux->poke_tab); 266 kfree(fp->aux); 267 } 268 free_percpu(fp->stats); 269 free_percpu(fp->active); 270 vfree(fp); 271 } 272 273 int bpf_prog_calc_tag(struct bpf_prog *fp) 274 { 275 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64); 276 u32 raw_size = bpf_prog_tag_scratch_size(fp); 277 u32 digest[SHA1_DIGEST_WORDS]; 278 u32 ws[SHA1_WORKSPACE_WORDS]; 279 u32 i, bsize, psize, blocks; 280 struct bpf_insn *dst; 281 bool was_ld_map; 282 u8 *raw, *todo; 283 __be32 *result; 284 __be64 *bits; 285 286 raw = vmalloc(raw_size); 287 if (!raw) 288 return -ENOMEM; 289 290 sha1_init(digest); 291 memset(ws, 0, sizeof(ws)); 292 293 /* We need to take out the map fd for the digest calculation 294 * since they are unstable from user space side. 295 */ 296 dst = (void *)raw; 297 for (i = 0, was_ld_map = false; i < fp->len; i++) { 298 dst[i] = fp->insnsi[i]; 299 if (!was_ld_map && 300 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 301 (dst[i].src_reg == BPF_PSEUDO_MAP_FD || 302 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { 303 was_ld_map = true; 304 dst[i].imm = 0; 305 } else if (was_ld_map && 306 dst[i].code == 0 && 307 dst[i].dst_reg == 0 && 308 dst[i].src_reg == 0 && 309 dst[i].off == 0) { 310 was_ld_map = false; 311 dst[i].imm = 0; 312 } else { 313 was_ld_map = false; 314 } 315 } 316 317 psize = bpf_prog_insn_size(fp); 318 memset(&raw[psize], 0, raw_size - psize); 319 raw[psize++] = 0x80; 320 321 bsize = round_up(psize, SHA1_BLOCK_SIZE); 322 blocks = bsize / SHA1_BLOCK_SIZE; 323 todo = raw; 324 if (bsize - psize >= sizeof(__be64)) { 325 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 326 } else { 327 bits = (__be64 *)(todo + bsize + bits_offset); 328 blocks++; 329 } 330 *bits = cpu_to_be64((psize - 1) << 3); 331 332 while (blocks--) { 333 sha1_transform(digest, todo, ws); 334 todo += SHA1_BLOCK_SIZE; 335 } 336 337 result = (__force __be32 *)digest; 338 for (i = 0; i < SHA1_DIGEST_WORDS; i++) 339 result[i] = cpu_to_be32(digest[i]); 340 memcpy(fp->tag, result, sizeof(fp->tag)); 341 342 vfree(raw); 343 return 0; 344 } 345 346 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, 347 s32 end_new, s32 curr, const bool probe_pass) 348 { 349 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 350 s32 delta = end_new - end_old; 351 s64 imm = insn->imm; 352 353 if (curr < pos && curr + imm + 1 >= end_old) 354 imm += delta; 355 else if (curr >= end_new && curr + imm + 1 < end_new) 356 imm -= delta; 357 if (imm < imm_min || imm > imm_max) 358 return -ERANGE; 359 if (!probe_pass) 360 insn->imm = imm; 361 return 0; 362 } 363 364 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, 365 s32 end_new, s32 curr, const bool probe_pass) 366 { 367 const s32 off_min = S16_MIN, off_max = S16_MAX; 368 s32 delta = end_new - end_old; 369 s32 off = insn->off; 370 371 if (curr < pos && curr + off + 1 >= end_old) 372 off += delta; 373 else if (curr >= end_new && curr + off + 1 < end_new) 374 off -= delta; 375 if (off < off_min || off > off_max) 376 return -ERANGE; 377 if (!probe_pass) 378 insn->off = off; 379 return 0; 380 } 381 382 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 383 s32 end_new, const bool probe_pass) 384 { 385 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); 386 struct bpf_insn *insn = prog->insnsi; 387 int ret = 0; 388 389 for (i = 0; i < insn_cnt; i++, insn++) { 390 u8 code; 391 392 /* In the probing pass we still operate on the original, 393 * unpatched image in order to check overflows before we 394 * do any other adjustments. Therefore skip the patchlet. 395 */ 396 if (probe_pass && i == pos) { 397 i = end_new; 398 insn = prog->insnsi + end_old; 399 } 400 if (bpf_pseudo_func(insn)) { 401 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 402 end_new, i, probe_pass); 403 if (ret) 404 return ret; 405 continue; 406 } 407 code = insn->code; 408 if ((BPF_CLASS(code) != BPF_JMP && 409 BPF_CLASS(code) != BPF_JMP32) || 410 BPF_OP(code) == BPF_EXIT) 411 continue; 412 /* Adjust offset of jmps if we cross patch boundaries. */ 413 if (BPF_OP(code) == BPF_CALL) { 414 if (insn->src_reg != BPF_PSEUDO_CALL) 415 continue; 416 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 417 end_new, i, probe_pass); 418 } else { 419 ret = bpf_adj_delta_to_off(insn, pos, end_old, 420 end_new, i, probe_pass); 421 } 422 if (ret) 423 break; 424 } 425 426 return ret; 427 } 428 429 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 430 { 431 struct bpf_line_info *linfo; 432 u32 i, nr_linfo; 433 434 nr_linfo = prog->aux->nr_linfo; 435 if (!nr_linfo || !delta) 436 return; 437 438 linfo = prog->aux->linfo; 439 440 for (i = 0; i < nr_linfo; i++) 441 if (off < linfo[i].insn_off) 442 break; 443 444 /* Push all off < linfo[i].insn_off by delta */ 445 for (; i < nr_linfo; i++) 446 linfo[i].insn_off += delta; 447 } 448 449 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 450 const struct bpf_insn *patch, u32 len) 451 { 452 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 453 const u32 cnt_max = S16_MAX; 454 struct bpf_prog *prog_adj; 455 int err; 456 457 /* Since our patchlet doesn't expand the image, we're done. */ 458 if (insn_delta == 0) { 459 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 460 return prog; 461 } 462 463 insn_adj_cnt = prog->len + insn_delta; 464 465 /* Reject anything that would potentially let the insn->off 466 * target overflow when we have excessive program expansions. 467 * We need to probe here before we do any reallocation where 468 * we afterwards may not fail anymore. 469 */ 470 if (insn_adj_cnt > cnt_max && 471 (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) 472 return ERR_PTR(err); 473 474 /* Several new instructions need to be inserted. Make room 475 * for them. Likely, there's no need for a new allocation as 476 * last page could have large enough tailroom. 477 */ 478 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 479 GFP_USER); 480 if (!prog_adj) 481 return ERR_PTR(-ENOMEM); 482 483 prog_adj->len = insn_adj_cnt; 484 485 /* Patching happens in 3 steps: 486 * 487 * 1) Move over tail of insnsi from next instruction onwards, 488 * so we can patch the single target insn with one or more 489 * new ones (patching is always from 1 to n insns, n > 0). 490 * 2) Inject new instructions at the target location. 491 * 3) Adjust branch offsets if necessary. 492 */ 493 insn_rest = insn_adj_cnt - off - len; 494 495 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 496 sizeof(*patch) * insn_rest); 497 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 498 499 /* We are guaranteed to not fail at this point, otherwise 500 * the ship has sailed to reverse to the original state. An 501 * overflow cannot happen at this point. 502 */ 503 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); 504 505 bpf_adj_linfo(prog_adj, off, insn_delta); 506 507 return prog_adj; 508 } 509 510 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) 511 { 512 /* Branch offsets can't overflow when program is shrinking, no need 513 * to call bpf_adj_branches(..., true) here 514 */ 515 memmove(prog->insnsi + off, prog->insnsi + off + cnt, 516 sizeof(struct bpf_insn) * (prog->len - off - cnt)); 517 prog->len -= cnt; 518 519 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); 520 } 521 522 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 523 { 524 int i; 525 526 for (i = 0; i < fp->aux->func_cnt; i++) 527 bpf_prog_kallsyms_del(fp->aux->func[i]); 528 } 529 530 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 531 { 532 bpf_prog_kallsyms_del_subprogs(fp); 533 bpf_prog_kallsyms_del(fp); 534 } 535 536 #ifdef CONFIG_BPF_JIT 537 /* All BPF JIT sysctl knobs here. */ 538 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 539 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 540 int bpf_jit_harden __read_mostly; 541 long bpf_jit_limit __read_mostly; 542 long bpf_jit_limit_max __read_mostly; 543 544 static void 545 bpf_prog_ksym_set_addr(struct bpf_prog *prog) 546 { 547 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 548 549 prog->aux->ksym.start = (unsigned long) prog->bpf_func; 550 prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len; 551 } 552 553 static void 554 bpf_prog_ksym_set_name(struct bpf_prog *prog) 555 { 556 char *sym = prog->aux->ksym.name; 557 const char *end = sym + KSYM_NAME_LEN; 558 const struct btf_type *type; 559 const char *func_name; 560 561 BUILD_BUG_ON(sizeof("bpf_prog_") + 562 sizeof(prog->tag) * 2 + 563 /* name has been null terminated. 564 * We should need +1 for the '_' preceding 565 * the name. However, the null character 566 * is double counted between the name and the 567 * sizeof("bpf_prog_") above, so we omit 568 * the +1 here. 569 */ 570 sizeof(prog->aux->name) > KSYM_NAME_LEN); 571 572 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 573 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 574 575 /* prog->aux->name will be ignored if full btf name is available */ 576 if (prog->aux->func_info_cnt) { 577 type = btf_type_by_id(prog->aux->btf, 578 prog->aux->func_info[prog->aux->func_idx].type_id); 579 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 580 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 581 return; 582 } 583 584 if (prog->aux->name[0]) 585 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 586 else 587 *sym = 0; 588 } 589 590 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) 591 { 592 return container_of(n, struct bpf_ksym, tnode)->start; 593 } 594 595 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 596 struct latch_tree_node *b) 597 { 598 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); 599 } 600 601 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 602 { 603 unsigned long val = (unsigned long)key; 604 const struct bpf_ksym *ksym; 605 606 ksym = container_of(n, struct bpf_ksym, tnode); 607 608 if (val < ksym->start) 609 return -1; 610 if (val >= ksym->end) 611 return 1; 612 613 return 0; 614 } 615 616 static const struct latch_tree_ops bpf_tree_ops = { 617 .less = bpf_tree_less, 618 .comp = bpf_tree_comp, 619 }; 620 621 static DEFINE_SPINLOCK(bpf_lock); 622 static LIST_HEAD(bpf_kallsyms); 623 static struct latch_tree_root bpf_tree __cacheline_aligned; 624 625 void bpf_ksym_add(struct bpf_ksym *ksym) 626 { 627 spin_lock_bh(&bpf_lock); 628 WARN_ON_ONCE(!list_empty(&ksym->lnode)); 629 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); 630 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 631 spin_unlock_bh(&bpf_lock); 632 } 633 634 static void __bpf_ksym_del(struct bpf_ksym *ksym) 635 { 636 if (list_empty(&ksym->lnode)) 637 return; 638 639 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 640 list_del_rcu(&ksym->lnode); 641 } 642 643 void bpf_ksym_del(struct bpf_ksym *ksym) 644 { 645 spin_lock_bh(&bpf_lock); 646 __bpf_ksym_del(ksym); 647 spin_unlock_bh(&bpf_lock); 648 } 649 650 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 651 { 652 return fp->jited && !bpf_prog_was_classic(fp); 653 } 654 655 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp) 656 { 657 return list_empty(&fp->aux->ksym.lnode) || 658 fp->aux->ksym.lnode.prev == LIST_POISON2; 659 } 660 661 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 662 { 663 if (!bpf_prog_kallsyms_candidate(fp) || 664 !bpf_capable()) 665 return; 666 667 bpf_prog_ksym_set_addr(fp); 668 bpf_prog_ksym_set_name(fp); 669 fp->aux->ksym.prog = true; 670 671 bpf_ksym_add(&fp->aux->ksym); 672 } 673 674 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 675 { 676 if (!bpf_prog_kallsyms_candidate(fp)) 677 return; 678 679 bpf_ksym_del(&fp->aux->ksym); 680 } 681 682 static struct bpf_ksym *bpf_ksym_find(unsigned long addr) 683 { 684 struct latch_tree_node *n; 685 686 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 687 return n ? container_of(n, struct bpf_ksym, tnode) : NULL; 688 } 689 690 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, 691 unsigned long *off, char *sym) 692 { 693 struct bpf_ksym *ksym; 694 char *ret = NULL; 695 696 rcu_read_lock(); 697 ksym = bpf_ksym_find(addr); 698 if (ksym) { 699 unsigned long symbol_start = ksym->start; 700 unsigned long symbol_end = ksym->end; 701 702 strncpy(sym, ksym->name, KSYM_NAME_LEN); 703 704 ret = sym; 705 if (size) 706 *size = symbol_end - symbol_start; 707 if (off) 708 *off = addr - symbol_start; 709 } 710 rcu_read_unlock(); 711 712 return ret; 713 } 714 715 bool is_bpf_text_address(unsigned long addr) 716 { 717 bool ret; 718 719 rcu_read_lock(); 720 ret = bpf_ksym_find(addr) != NULL; 721 rcu_read_unlock(); 722 723 return ret; 724 } 725 726 static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) 727 { 728 struct bpf_ksym *ksym = bpf_ksym_find(addr); 729 730 return ksym && ksym->prog ? 731 container_of(ksym, struct bpf_prog_aux, ksym)->prog : 732 NULL; 733 } 734 735 const struct exception_table_entry *search_bpf_extables(unsigned long addr) 736 { 737 const struct exception_table_entry *e = NULL; 738 struct bpf_prog *prog; 739 740 rcu_read_lock(); 741 prog = bpf_prog_ksym_find(addr); 742 if (!prog) 743 goto out; 744 if (!prog->aux->num_exentries) 745 goto out; 746 747 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); 748 out: 749 rcu_read_unlock(); 750 return e; 751 } 752 753 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 754 char *sym) 755 { 756 struct bpf_ksym *ksym; 757 unsigned int it = 0; 758 int ret = -ERANGE; 759 760 if (!bpf_jit_kallsyms_enabled()) 761 return ret; 762 763 rcu_read_lock(); 764 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { 765 if (it++ != symnum) 766 continue; 767 768 strncpy(sym, ksym->name, KSYM_NAME_LEN); 769 770 *value = ksym->start; 771 *type = BPF_SYM_ELF_TYPE; 772 773 ret = 0; 774 break; 775 } 776 rcu_read_unlock(); 777 778 return ret; 779 } 780 781 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, 782 struct bpf_jit_poke_descriptor *poke) 783 { 784 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; 785 static const u32 poke_tab_max = 1024; 786 u32 slot = prog->aux->size_poke_tab; 787 u32 size = slot + 1; 788 789 if (size > poke_tab_max) 790 return -ENOSPC; 791 if (poke->tailcall_target || poke->tailcall_target_stable || 792 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) 793 return -EINVAL; 794 795 switch (poke->reason) { 796 case BPF_POKE_REASON_TAIL_CALL: 797 if (!poke->tail_call.map) 798 return -EINVAL; 799 break; 800 default: 801 return -EINVAL; 802 } 803 804 tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL); 805 if (!tab) 806 return -ENOMEM; 807 808 memcpy(&tab[slot], poke, sizeof(*poke)); 809 prog->aux->size_poke_tab = size; 810 prog->aux->poke_tab = tab; 811 812 return slot; 813 } 814 815 /* 816 * BPF program pack allocator. 817 * 818 * Most BPF programs are pretty small. Allocating a hole page for each 819 * program is sometime a waste. Many small bpf program also adds pressure 820 * to instruction TLB. To solve this issue, we introduce a BPF program pack 821 * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86) 822 * to host BPF programs. 823 */ 824 #define BPF_PROG_CHUNK_SHIFT 6 825 #define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT) 826 #define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1)) 827 828 struct bpf_prog_pack { 829 struct list_head list; 830 void *ptr; 831 unsigned long bitmap[]; 832 }; 833 834 #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) 835 836 static size_t bpf_prog_pack_size = -1; 837 static size_t bpf_prog_pack_mask = -1; 838 839 static int bpf_prog_chunk_count(void) 840 { 841 WARN_ON_ONCE(bpf_prog_pack_size == -1); 842 return bpf_prog_pack_size / BPF_PROG_CHUNK_SIZE; 843 } 844 845 static DEFINE_MUTEX(pack_mutex); 846 static LIST_HEAD(pack_list); 847 848 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with 849 * CONFIG_MMU=n. Use PAGE_SIZE in these cases. 850 */ 851 #ifdef PMD_SIZE 852 #define BPF_HPAGE_SIZE PMD_SIZE 853 #define BPF_HPAGE_MASK PMD_MASK 854 #else 855 #define BPF_HPAGE_SIZE PAGE_SIZE 856 #define BPF_HPAGE_MASK PAGE_MASK 857 #endif 858 859 static size_t select_bpf_prog_pack_size(void) 860 { 861 size_t size; 862 void *ptr; 863 864 size = BPF_HPAGE_SIZE * num_online_nodes(); 865 ptr = module_alloc(size); 866 867 /* Test whether we can get huge pages. If not just use PAGE_SIZE 868 * packs. 869 */ 870 if (!ptr || !is_vm_area_hugepages(ptr)) { 871 size = PAGE_SIZE; 872 bpf_prog_pack_mask = PAGE_MASK; 873 } else { 874 bpf_prog_pack_mask = BPF_HPAGE_MASK; 875 } 876 877 vfree(ptr); 878 return size; 879 } 880 881 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) 882 { 883 struct bpf_prog_pack *pack; 884 885 pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(bpf_prog_chunk_count())), 886 GFP_KERNEL); 887 if (!pack) 888 return NULL; 889 pack->ptr = module_alloc(bpf_prog_pack_size); 890 if (!pack->ptr) { 891 kfree(pack); 892 return NULL; 893 } 894 bpf_fill_ill_insns(pack->ptr, bpf_prog_pack_size); 895 bitmap_zero(pack->bitmap, bpf_prog_pack_size / BPF_PROG_CHUNK_SIZE); 896 list_add_tail(&pack->list, &pack_list); 897 898 set_vm_flush_reset_perms(pack->ptr); 899 set_memory_ro((unsigned long)pack->ptr, bpf_prog_pack_size / PAGE_SIZE); 900 set_memory_x((unsigned long)pack->ptr, bpf_prog_pack_size / PAGE_SIZE); 901 return pack; 902 } 903 904 static void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) 905 { 906 unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); 907 struct bpf_prog_pack *pack; 908 unsigned long pos; 909 void *ptr = NULL; 910 911 mutex_lock(&pack_mutex); 912 if (bpf_prog_pack_size == -1) 913 bpf_prog_pack_size = select_bpf_prog_pack_size(); 914 915 if (size > bpf_prog_pack_size) { 916 size = round_up(size, PAGE_SIZE); 917 ptr = module_alloc(size); 918 if (ptr) { 919 bpf_fill_ill_insns(ptr, size); 920 set_vm_flush_reset_perms(ptr); 921 set_memory_ro((unsigned long)ptr, size / PAGE_SIZE); 922 set_memory_x((unsigned long)ptr, size / PAGE_SIZE); 923 } 924 goto out; 925 } 926 list_for_each_entry(pack, &pack_list, list) { 927 pos = bitmap_find_next_zero_area(pack->bitmap, bpf_prog_chunk_count(), 0, 928 nbits, 0); 929 if (pos < bpf_prog_chunk_count()) 930 goto found_free_area; 931 } 932 933 pack = alloc_new_pack(bpf_fill_ill_insns); 934 if (!pack) 935 goto out; 936 937 pos = 0; 938 939 found_free_area: 940 bitmap_set(pack->bitmap, pos, nbits); 941 ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT); 942 943 out: 944 mutex_unlock(&pack_mutex); 945 return ptr; 946 } 947 948 static void bpf_prog_pack_free(struct bpf_binary_header *hdr) 949 { 950 struct bpf_prog_pack *pack = NULL, *tmp; 951 unsigned int nbits; 952 unsigned long pos; 953 void *pack_ptr; 954 955 mutex_lock(&pack_mutex); 956 if (hdr->size > bpf_prog_pack_size) { 957 module_memfree(hdr); 958 goto out; 959 } 960 961 pack_ptr = (void *)((unsigned long)hdr & bpf_prog_pack_mask); 962 963 list_for_each_entry(tmp, &pack_list, list) { 964 if (tmp->ptr == pack_ptr) { 965 pack = tmp; 966 break; 967 } 968 } 969 970 if (WARN_ONCE(!pack, "bpf_prog_pack bug\n")) 971 goto out; 972 973 nbits = BPF_PROG_SIZE_TO_NBITS(hdr->size); 974 pos = ((unsigned long)hdr - (unsigned long)pack_ptr) >> BPF_PROG_CHUNK_SHIFT; 975 976 WARN_ONCE(bpf_arch_text_invalidate(hdr, hdr->size), 977 "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n"); 978 979 bitmap_clear(pack->bitmap, pos, nbits); 980 if (bitmap_find_next_zero_area(pack->bitmap, bpf_prog_chunk_count(), 0, 981 bpf_prog_chunk_count(), 0) == 0) { 982 list_del(&pack->list); 983 module_memfree(pack->ptr); 984 kfree(pack); 985 } 986 out: 987 mutex_unlock(&pack_mutex); 988 } 989 990 static atomic_long_t bpf_jit_current; 991 992 /* Can be overridden by an arch's JIT compiler if it has a custom, 993 * dedicated BPF backend memory area, or if neither of the two 994 * below apply. 995 */ 996 u64 __weak bpf_jit_alloc_exec_limit(void) 997 { 998 #if defined(MODULES_VADDR) 999 return MODULES_END - MODULES_VADDR; 1000 #else 1001 return VMALLOC_END - VMALLOC_START; 1002 #endif 1003 } 1004 1005 static int __init bpf_jit_charge_init(void) 1006 { 1007 /* Only used as heuristic here to derive limit. */ 1008 bpf_jit_limit_max = bpf_jit_alloc_exec_limit(); 1009 bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 2, 1010 PAGE_SIZE), LONG_MAX); 1011 return 0; 1012 } 1013 pure_initcall(bpf_jit_charge_init); 1014 1015 int bpf_jit_charge_modmem(u32 size) 1016 { 1017 if (atomic_long_add_return(size, &bpf_jit_current) > bpf_jit_limit) { 1018 if (!bpf_capable()) { 1019 atomic_long_sub(size, &bpf_jit_current); 1020 return -EPERM; 1021 } 1022 } 1023 1024 return 0; 1025 } 1026 1027 void bpf_jit_uncharge_modmem(u32 size) 1028 { 1029 atomic_long_sub(size, &bpf_jit_current); 1030 } 1031 1032 void *__weak bpf_jit_alloc_exec(unsigned long size) 1033 { 1034 return module_alloc(size); 1035 } 1036 1037 void __weak bpf_jit_free_exec(void *addr) 1038 { 1039 module_memfree(addr); 1040 } 1041 1042 struct bpf_binary_header * 1043 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 1044 unsigned int alignment, 1045 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1046 { 1047 struct bpf_binary_header *hdr; 1048 u32 size, hole, start; 1049 1050 WARN_ON_ONCE(!is_power_of_2(alignment) || 1051 alignment > BPF_IMAGE_ALIGNMENT); 1052 1053 /* Most of BPF filters are really small, but if some of them 1054 * fill a page, allow at least 128 extra bytes to insert a 1055 * random section of illegal instructions. 1056 */ 1057 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 1058 1059 if (bpf_jit_charge_modmem(size)) 1060 return NULL; 1061 hdr = bpf_jit_alloc_exec(size); 1062 if (!hdr) { 1063 bpf_jit_uncharge_modmem(size); 1064 return NULL; 1065 } 1066 1067 /* Fill space with illegal/arch-dep instructions. */ 1068 bpf_fill_ill_insns(hdr, size); 1069 1070 hdr->size = size; 1071 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 1072 PAGE_SIZE - sizeof(*hdr)); 1073 start = (get_random_int() % hole) & ~(alignment - 1); 1074 1075 /* Leave a random number of instructions before BPF code. */ 1076 *image_ptr = &hdr->image[start]; 1077 1078 return hdr; 1079 } 1080 1081 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 1082 { 1083 u32 size = hdr->size; 1084 1085 bpf_jit_free_exec(hdr); 1086 bpf_jit_uncharge_modmem(size); 1087 } 1088 1089 /* Allocate jit binary from bpf_prog_pack allocator. 1090 * Since the allocated memory is RO+X, the JIT engine cannot write directly 1091 * to the memory. To solve this problem, a RW buffer is also allocated at 1092 * as the same time. The JIT engine should calculate offsets based on the 1093 * RO memory address, but write JITed program to the RW buffer. Once the 1094 * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies 1095 * the JITed program to the RO memory. 1096 */ 1097 struct bpf_binary_header * 1098 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr, 1099 unsigned int alignment, 1100 struct bpf_binary_header **rw_header, 1101 u8 **rw_image, 1102 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1103 { 1104 struct bpf_binary_header *ro_header; 1105 u32 size, hole, start; 1106 1107 WARN_ON_ONCE(!is_power_of_2(alignment) || 1108 alignment > BPF_IMAGE_ALIGNMENT); 1109 1110 /* add 16 bytes for a random section of illegal instructions */ 1111 size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE); 1112 1113 if (bpf_jit_charge_modmem(size)) 1114 return NULL; 1115 ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns); 1116 if (!ro_header) { 1117 bpf_jit_uncharge_modmem(size); 1118 return NULL; 1119 } 1120 1121 *rw_header = kvmalloc(size, GFP_KERNEL); 1122 if (!*rw_header) { 1123 bpf_arch_text_copy(&ro_header->size, &size, sizeof(size)); 1124 bpf_prog_pack_free(ro_header); 1125 bpf_jit_uncharge_modmem(size); 1126 return NULL; 1127 } 1128 1129 /* Fill space with illegal/arch-dep instructions. */ 1130 bpf_fill_ill_insns(*rw_header, size); 1131 (*rw_header)->size = size; 1132 1133 hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)), 1134 BPF_PROG_CHUNK_SIZE - sizeof(*ro_header)); 1135 start = (get_random_int() % hole) & ~(alignment - 1); 1136 1137 *image_ptr = &ro_header->image[start]; 1138 *rw_image = &(*rw_header)->image[start]; 1139 1140 return ro_header; 1141 } 1142 1143 /* Copy JITed text from rw_header to its final location, the ro_header. */ 1144 int bpf_jit_binary_pack_finalize(struct bpf_prog *prog, 1145 struct bpf_binary_header *ro_header, 1146 struct bpf_binary_header *rw_header) 1147 { 1148 void *ptr; 1149 1150 ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size); 1151 1152 kvfree(rw_header); 1153 1154 if (IS_ERR(ptr)) { 1155 bpf_prog_pack_free(ro_header); 1156 return PTR_ERR(ptr); 1157 } 1158 prog->aux->use_bpf_prog_pack = true; 1159 return 0; 1160 } 1161 1162 /* bpf_jit_binary_pack_free is called in two different scenarios: 1163 * 1) when the program is freed after; 1164 * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize). 1165 * For case 2), we need to free both the RO memory and the RW buffer. 1166 * 1167 * bpf_jit_binary_pack_free requires proper ro_header->size. However, 1168 * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size 1169 * must be set with either bpf_jit_binary_pack_finalize (normal path) or 1170 * bpf_arch_text_copy (when jit fails). 1171 */ 1172 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header, 1173 struct bpf_binary_header *rw_header) 1174 { 1175 u32 size = ro_header->size; 1176 1177 bpf_prog_pack_free(ro_header); 1178 kvfree(rw_header); 1179 bpf_jit_uncharge_modmem(size); 1180 } 1181 1182 static inline struct bpf_binary_header * 1183 bpf_jit_binary_hdr(const struct bpf_prog *fp) 1184 { 1185 unsigned long real_start = (unsigned long)fp->bpf_func; 1186 unsigned long addr; 1187 1188 if (fp->aux->use_bpf_prog_pack) 1189 addr = real_start & BPF_PROG_CHUNK_MASK; 1190 else 1191 addr = real_start & PAGE_MASK; 1192 1193 return (void *)addr; 1194 } 1195 1196 /* This symbol is only overridden by archs that have different 1197 * requirements than the usual eBPF JITs, f.e. when they only 1198 * implement cBPF JIT, do not set images read-only, etc. 1199 */ 1200 void __weak bpf_jit_free(struct bpf_prog *fp) 1201 { 1202 if (fp->jited) { 1203 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 1204 1205 if (fp->aux->use_bpf_prog_pack) 1206 bpf_jit_binary_pack_free(hdr, NULL /* rw_buffer */); 1207 else 1208 bpf_jit_binary_free(hdr); 1209 1210 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 1211 } 1212 1213 bpf_prog_unlock_free(fp); 1214 } 1215 1216 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 1217 const struct bpf_insn *insn, bool extra_pass, 1218 u64 *func_addr, bool *func_addr_fixed) 1219 { 1220 s16 off = insn->off; 1221 s32 imm = insn->imm; 1222 u8 *addr; 1223 1224 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 1225 if (!*func_addr_fixed) { 1226 /* Place-holder address till the last pass has collected 1227 * all addresses for JITed subprograms in which case we 1228 * can pick them up from prog->aux. 1229 */ 1230 if (!extra_pass) 1231 addr = NULL; 1232 else if (prog->aux->func && 1233 off >= 0 && off < prog->aux->func_cnt) 1234 addr = (u8 *)prog->aux->func[off]->bpf_func; 1235 else 1236 return -EINVAL; 1237 } else { 1238 /* Address of a BPF helper call. Since part of the core 1239 * kernel, it's always at a fixed location. __bpf_call_base 1240 * and the helper with imm relative to it are both in core 1241 * kernel. 1242 */ 1243 addr = (u8 *)__bpf_call_base + imm; 1244 } 1245 1246 *func_addr = (unsigned long)addr; 1247 return 0; 1248 } 1249 1250 static int bpf_jit_blind_insn(const struct bpf_insn *from, 1251 const struct bpf_insn *aux, 1252 struct bpf_insn *to_buff, 1253 bool emit_zext) 1254 { 1255 struct bpf_insn *to = to_buff; 1256 u32 imm_rnd = get_random_int(); 1257 s16 off; 1258 1259 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 1260 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 1261 1262 /* Constraints on AX register: 1263 * 1264 * AX register is inaccessible from user space. It is mapped in 1265 * all JITs, and used here for constant blinding rewrites. It is 1266 * typically "stateless" meaning its contents are only valid within 1267 * the executed instruction, but not across several instructions. 1268 * There are a few exceptions however which are further detailed 1269 * below. 1270 * 1271 * Constant blinding is only used by JITs, not in the interpreter. 1272 * The interpreter uses AX in some occasions as a local temporary 1273 * register e.g. in DIV or MOD instructions. 1274 * 1275 * In restricted circumstances, the verifier can also use the AX 1276 * register for rewrites as long as they do not interfere with 1277 * the above cases! 1278 */ 1279 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 1280 goto out; 1281 1282 if (from->imm == 0 && 1283 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 1284 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 1285 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 1286 goto out; 1287 } 1288 1289 switch (from->code) { 1290 case BPF_ALU | BPF_ADD | BPF_K: 1291 case BPF_ALU | BPF_SUB | BPF_K: 1292 case BPF_ALU | BPF_AND | BPF_K: 1293 case BPF_ALU | BPF_OR | BPF_K: 1294 case BPF_ALU | BPF_XOR | BPF_K: 1295 case BPF_ALU | BPF_MUL | BPF_K: 1296 case BPF_ALU | BPF_MOV | BPF_K: 1297 case BPF_ALU | BPF_DIV | BPF_K: 1298 case BPF_ALU | BPF_MOD | BPF_K: 1299 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1300 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1301 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 1302 break; 1303 1304 case BPF_ALU64 | BPF_ADD | BPF_K: 1305 case BPF_ALU64 | BPF_SUB | BPF_K: 1306 case BPF_ALU64 | BPF_AND | BPF_K: 1307 case BPF_ALU64 | BPF_OR | BPF_K: 1308 case BPF_ALU64 | BPF_XOR | BPF_K: 1309 case BPF_ALU64 | BPF_MUL | BPF_K: 1310 case BPF_ALU64 | BPF_MOV | BPF_K: 1311 case BPF_ALU64 | BPF_DIV | BPF_K: 1312 case BPF_ALU64 | BPF_MOD | BPF_K: 1313 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1314 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1315 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 1316 break; 1317 1318 case BPF_JMP | BPF_JEQ | BPF_K: 1319 case BPF_JMP | BPF_JNE | BPF_K: 1320 case BPF_JMP | BPF_JGT | BPF_K: 1321 case BPF_JMP | BPF_JLT | BPF_K: 1322 case BPF_JMP | BPF_JGE | BPF_K: 1323 case BPF_JMP | BPF_JLE | BPF_K: 1324 case BPF_JMP | BPF_JSGT | BPF_K: 1325 case BPF_JMP | BPF_JSLT | BPF_K: 1326 case BPF_JMP | BPF_JSGE | BPF_K: 1327 case BPF_JMP | BPF_JSLE | BPF_K: 1328 case BPF_JMP | BPF_JSET | BPF_K: 1329 /* Accommodate for extra offset in case of a backjump. */ 1330 off = from->off; 1331 if (off < 0) 1332 off -= 2; 1333 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1334 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1335 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1336 break; 1337 1338 case BPF_JMP32 | BPF_JEQ | BPF_K: 1339 case BPF_JMP32 | BPF_JNE | BPF_K: 1340 case BPF_JMP32 | BPF_JGT | BPF_K: 1341 case BPF_JMP32 | BPF_JLT | BPF_K: 1342 case BPF_JMP32 | BPF_JGE | BPF_K: 1343 case BPF_JMP32 | BPF_JLE | BPF_K: 1344 case BPF_JMP32 | BPF_JSGT | BPF_K: 1345 case BPF_JMP32 | BPF_JSLT | BPF_K: 1346 case BPF_JMP32 | BPF_JSGE | BPF_K: 1347 case BPF_JMP32 | BPF_JSLE | BPF_K: 1348 case BPF_JMP32 | BPF_JSET | BPF_K: 1349 /* Accommodate for extra offset in case of a backjump. */ 1350 off = from->off; 1351 if (off < 0) 1352 off -= 2; 1353 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1354 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1355 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1356 off); 1357 break; 1358 1359 case BPF_LD | BPF_IMM | BPF_DW: 1360 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1361 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1362 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1363 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1364 break; 1365 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1366 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1367 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1368 if (emit_zext) 1369 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1370 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1371 break; 1372 1373 case BPF_ST | BPF_MEM | BPF_DW: 1374 case BPF_ST | BPF_MEM | BPF_W: 1375 case BPF_ST | BPF_MEM | BPF_H: 1376 case BPF_ST | BPF_MEM | BPF_B: 1377 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1378 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1379 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1380 break; 1381 } 1382 out: 1383 return to - to_buff; 1384 } 1385 1386 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1387 gfp_t gfp_extra_flags) 1388 { 1389 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1390 struct bpf_prog *fp; 1391 1392 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1393 if (fp != NULL) { 1394 /* aux->prog still points to the fp_other one, so 1395 * when promoting the clone to the real program, 1396 * this still needs to be adapted. 1397 */ 1398 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1399 } 1400 1401 return fp; 1402 } 1403 1404 static void bpf_prog_clone_free(struct bpf_prog *fp) 1405 { 1406 /* aux was stolen by the other clone, so we cannot free 1407 * it from this path! It will be freed eventually by the 1408 * other program on release. 1409 * 1410 * At this point, we don't need a deferred release since 1411 * clone is guaranteed to not be locked. 1412 */ 1413 fp->aux = NULL; 1414 fp->stats = NULL; 1415 fp->active = NULL; 1416 __bpf_prog_free(fp); 1417 } 1418 1419 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1420 { 1421 /* We have to repoint aux->prog to self, as we don't 1422 * know whether fp here is the clone or the original. 1423 */ 1424 fp->aux->prog = fp; 1425 bpf_prog_clone_free(fp_other); 1426 } 1427 1428 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1429 { 1430 struct bpf_insn insn_buff[16], aux[2]; 1431 struct bpf_prog *clone, *tmp; 1432 int insn_delta, insn_cnt; 1433 struct bpf_insn *insn; 1434 int i, rewritten; 1435 1436 if (!prog->blinding_requested || prog->blinded) 1437 return prog; 1438 1439 clone = bpf_prog_clone_create(prog, GFP_USER); 1440 if (!clone) 1441 return ERR_PTR(-ENOMEM); 1442 1443 insn_cnt = clone->len; 1444 insn = clone->insnsi; 1445 1446 for (i = 0; i < insn_cnt; i++, insn++) { 1447 if (bpf_pseudo_func(insn)) { 1448 /* ld_imm64 with an address of bpf subprog is not 1449 * a user controlled constant. Don't randomize it, 1450 * since it will conflict with jit_subprogs() logic. 1451 */ 1452 insn++; 1453 i++; 1454 continue; 1455 } 1456 1457 /* We temporarily need to hold the original ld64 insn 1458 * so that we can still access the first part in the 1459 * second blinding run. 1460 */ 1461 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1462 insn[1].code == 0) 1463 memcpy(aux, insn, sizeof(aux)); 1464 1465 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1466 clone->aux->verifier_zext); 1467 if (!rewritten) 1468 continue; 1469 1470 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1471 if (IS_ERR(tmp)) { 1472 /* Patching may have repointed aux->prog during 1473 * realloc from the original one, so we need to 1474 * fix it up here on error. 1475 */ 1476 bpf_jit_prog_release_other(prog, clone); 1477 return tmp; 1478 } 1479 1480 clone = tmp; 1481 insn_delta = rewritten - 1; 1482 1483 /* Walk new program and skip insns we just inserted. */ 1484 insn = clone->insnsi + i + insn_delta; 1485 insn_cnt += insn_delta; 1486 i += insn_delta; 1487 } 1488 1489 clone->blinded = 1; 1490 return clone; 1491 } 1492 #endif /* CONFIG_BPF_JIT */ 1493 1494 /* Base function for offset calculation. Needs to go into .text section, 1495 * therefore keeping it non-static as well; will also be used by JITs 1496 * anyway later on, so do not let the compiler omit it. This also needs 1497 * to go into kallsyms for correlation from e.g. bpftool, so naming 1498 * must not change. 1499 */ 1500 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1501 { 1502 return 0; 1503 } 1504 EXPORT_SYMBOL_GPL(__bpf_call_base); 1505 1506 /* All UAPI available opcodes. */ 1507 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1508 /* 32 bit ALU operations. */ \ 1509 /* Register based. */ \ 1510 INSN_3(ALU, ADD, X), \ 1511 INSN_3(ALU, SUB, X), \ 1512 INSN_3(ALU, AND, X), \ 1513 INSN_3(ALU, OR, X), \ 1514 INSN_3(ALU, LSH, X), \ 1515 INSN_3(ALU, RSH, X), \ 1516 INSN_3(ALU, XOR, X), \ 1517 INSN_3(ALU, MUL, X), \ 1518 INSN_3(ALU, MOV, X), \ 1519 INSN_3(ALU, ARSH, X), \ 1520 INSN_3(ALU, DIV, X), \ 1521 INSN_3(ALU, MOD, X), \ 1522 INSN_2(ALU, NEG), \ 1523 INSN_3(ALU, END, TO_BE), \ 1524 INSN_3(ALU, END, TO_LE), \ 1525 /* Immediate based. */ \ 1526 INSN_3(ALU, ADD, K), \ 1527 INSN_3(ALU, SUB, K), \ 1528 INSN_3(ALU, AND, K), \ 1529 INSN_3(ALU, OR, K), \ 1530 INSN_3(ALU, LSH, K), \ 1531 INSN_3(ALU, RSH, K), \ 1532 INSN_3(ALU, XOR, K), \ 1533 INSN_3(ALU, MUL, K), \ 1534 INSN_3(ALU, MOV, K), \ 1535 INSN_3(ALU, ARSH, K), \ 1536 INSN_3(ALU, DIV, K), \ 1537 INSN_3(ALU, MOD, K), \ 1538 /* 64 bit ALU operations. */ \ 1539 /* Register based. */ \ 1540 INSN_3(ALU64, ADD, X), \ 1541 INSN_3(ALU64, SUB, X), \ 1542 INSN_3(ALU64, AND, X), \ 1543 INSN_3(ALU64, OR, X), \ 1544 INSN_3(ALU64, LSH, X), \ 1545 INSN_3(ALU64, RSH, X), \ 1546 INSN_3(ALU64, XOR, X), \ 1547 INSN_3(ALU64, MUL, X), \ 1548 INSN_3(ALU64, MOV, X), \ 1549 INSN_3(ALU64, ARSH, X), \ 1550 INSN_3(ALU64, DIV, X), \ 1551 INSN_3(ALU64, MOD, X), \ 1552 INSN_2(ALU64, NEG), \ 1553 /* Immediate based. */ \ 1554 INSN_3(ALU64, ADD, K), \ 1555 INSN_3(ALU64, SUB, K), \ 1556 INSN_3(ALU64, AND, K), \ 1557 INSN_3(ALU64, OR, K), \ 1558 INSN_3(ALU64, LSH, K), \ 1559 INSN_3(ALU64, RSH, K), \ 1560 INSN_3(ALU64, XOR, K), \ 1561 INSN_3(ALU64, MUL, K), \ 1562 INSN_3(ALU64, MOV, K), \ 1563 INSN_3(ALU64, ARSH, K), \ 1564 INSN_3(ALU64, DIV, K), \ 1565 INSN_3(ALU64, MOD, K), \ 1566 /* Call instruction. */ \ 1567 INSN_2(JMP, CALL), \ 1568 /* Exit instruction. */ \ 1569 INSN_2(JMP, EXIT), \ 1570 /* 32-bit Jump instructions. */ \ 1571 /* Register based. */ \ 1572 INSN_3(JMP32, JEQ, X), \ 1573 INSN_3(JMP32, JNE, X), \ 1574 INSN_3(JMP32, JGT, X), \ 1575 INSN_3(JMP32, JLT, X), \ 1576 INSN_3(JMP32, JGE, X), \ 1577 INSN_3(JMP32, JLE, X), \ 1578 INSN_3(JMP32, JSGT, X), \ 1579 INSN_3(JMP32, JSLT, X), \ 1580 INSN_3(JMP32, JSGE, X), \ 1581 INSN_3(JMP32, JSLE, X), \ 1582 INSN_3(JMP32, JSET, X), \ 1583 /* Immediate based. */ \ 1584 INSN_3(JMP32, JEQ, K), \ 1585 INSN_3(JMP32, JNE, K), \ 1586 INSN_3(JMP32, JGT, K), \ 1587 INSN_3(JMP32, JLT, K), \ 1588 INSN_3(JMP32, JGE, K), \ 1589 INSN_3(JMP32, JLE, K), \ 1590 INSN_3(JMP32, JSGT, K), \ 1591 INSN_3(JMP32, JSLT, K), \ 1592 INSN_3(JMP32, JSGE, K), \ 1593 INSN_3(JMP32, JSLE, K), \ 1594 INSN_3(JMP32, JSET, K), \ 1595 /* Jump instructions. */ \ 1596 /* Register based. */ \ 1597 INSN_3(JMP, JEQ, X), \ 1598 INSN_3(JMP, JNE, X), \ 1599 INSN_3(JMP, JGT, X), \ 1600 INSN_3(JMP, JLT, X), \ 1601 INSN_3(JMP, JGE, X), \ 1602 INSN_3(JMP, JLE, X), \ 1603 INSN_3(JMP, JSGT, X), \ 1604 INSN_3(JMP, JSLT, X), \ 1605 INSN_3(JMP, JSGE, X), \ 1606 INSN_3(JMP, JSLE, X), \ 1607 INSN_3(JMP, JSET, X), \ 1608 /* Immediate based. */ \ 1609 INSN_3(JMP, JEQ, K), \ 1610 INSN_3(JMP, JNE, K), \ 1611 INSN_3(JMP, JGT, K), \ 1612 INSN_3(JMP, JLT, K), \ 1613 INSN_3(JMP, JGE, K), \ 1614 INSN_3(JMP, JLE, K), \ 1615 INSN_3(JMP, JSGT, K), \ 1616 INSN_3(JMP, JSLT, K), \ 1617 INSN_3(JMP, JSGE, K), \ 1618 INSN_3(JMP, JSLE, K), \ 1619 INSN_3(JMP, JSET, K), \ 1620 INSN_2(JMP, JA), \ 1621 /* Store instructions. */ \ 1622 /* Register based. */ \ 1623 INSN_3(STX, MEM, B), \ 1624 INSN_3(STX, MEM, H), \ 1625 INSN_3(STX, MEM, W), \ 1626 INSN_3(STX, MEM, DW), \ 1627 INSN_3(STX, ATOMIC, W), \ 1628 INSN_3(STX, ATOMIC, DW), \ 1629 /* Immediate based. */ \ 1630 INSN_3(ST, MEM, B), \ 1631 INSN_3(ST, MEM, H), \ 1632 INSN_3(ST, MEM, W), \ 1633 INSN_3(ST, MEM, DW), \ 1634 /* Load instructions. */ \ 1635 /* Register based. */ \ 1636 INSN_3(LDX, MEM, B), \ 1637 INSN_3(LDX, MEM, H), \ 1638 INSN_3(LDX, MEM, W), \ 1639 INSN_3(LDX, MEM, DW), \ 1640 /* Immediate based. */ \ 1641 INSN_3(LD, IMM, DW) 1642 1643 bool bpf_opcode_in_insntable(u8 code) 1644 { 1645 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1646 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1647 static const bool public_insntable[256] = { 1648 [0 ... 255] = false, 1649 /* Now overwrite non-defaults ... */ 1650 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1651 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1652 [BPF_LD | BPF_ABS | BPF_B] = true, 1653 [BPF_LD | BPF_ABS | BPF_H] = true, 1654 [BPF_LD | BPF_ABS | BPF_W] = true, 1655 [BPF_LD | BPF_IND | BPF_B] = true, 1656 [BPF_LD | BPF_IND | BPF_H] = true, 1657 [BPF_LD | BPF_IND | BPF_W] = true, 1658 }; 1659 #undef BPF_INSN_3_TBL 1660 #undef BPF_INSN_2_TBL 1661 return public_insntable[code]; 1662 } 1663 1664 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1665 u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) 1666 { 1667 memset(dst, 0, size); 1668 return -EFAULT; 1669 } 1670 1671 /** 1672 * ___bpf_prog_run - run eBPF program on a given context 1673 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1674 * @insn: is the array of eBPF instructions 1675 * 1676 * Decode and execute eBPF instructions. 1677 * 1678 * Return: whatever value is in %BPF_R0 at program exit 1679 */ 1680 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) 1681 { 1682 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1683 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1684 static const void * const jumptable[256] __annotate_jump_table = { 1685 [0 ... 255] = &&default_label, 1686 /* Now overwrite non-defaults ... */ 1687 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1688 /* Non-UAPI available opcodes. */ 1689 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1690 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1691 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC, 1692 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1693 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1694 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1695 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1696 }; 1697 #undef BPF_INSN_3_LBL 1698 #undef BPF_INSN_2_LBL 1699 u32 tail_call_cnt = 0; 1700 1701 #define CONT ({ insn++; goto select_insn; }) 1702 #define CONT_JMP ({ insn++; goto select_insn; }) 1703 1704 select_insn: 1705 goto *jumptable[insn->code]; 1706 1707 /* Explicitly mask the register-based shift amounts with 63 or 31 1708 * to avoid undefined behavior. Normally this won't affect the 1709 * generated code, for example, in case of native 64 bit archs such 1710 * as x86-64 or arm64, the compiler is optimizing the AND away for 1711 * the interpreter. In case of JITs, each of the JIT backends compiles 1712 * the BPF shift operations to machine instructions which produce 1713 * implementation-defined results in such a case; the resulting 1714 * contents of the register may be arbitrary, but program behaviour 1715 * as a whole remains defined. In other words, in case of JIT backends, 1716 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation. 1717 */ 1718 /* ALU (shifts) */ 1719 #define SHT(OPCODE, OP) \ 1720 ALU64_##OPCODE##_X: \ 1721 DST = DST OP (SRC & 63); \ 1722 CONT; \ 1723 ALU_##OPCODE##_X: \ 1724 DST = (u32) DST OP ((u32) SRC & 31); \ 1725 CONT; \ 1726 ALU64_##OPCODE##_K: \ 1727 DST = DST OP IMM; \ 1728 CONT; \ 1729 ALU_##OPCODE##_K: \ 1730 DST = (u32) DST OP (u32) IMM; \ 1731 CONT; 1732 /* ALU (rest) */ 1733 #define ALU(OPCODE, OP) \ 1734 ALU64_##OPCODE##_X: \ 1735 DST = DST OP SRC; \ 1736 CONT; \ 1737 ALU_##OPCODE##_X: \ 1738 DST = (u32) DST OP (u32) SRC; \ 1739 CONT; \ 1740 ALU64_##OPCODE##_K: \ 1741 DST = DST OP IMM; \ 1742 CONT; \ 1743 ALU_##OPCODE##_K: \ 1744 DST = (u32) DST OP (u32) IMM; \ 1745 CONT; 1746 ALU(ADD, +) 1747 ALU(SUB, -) 1748 ALU(AND, &) 1749 ALU(OR, |) 1750 ALU(XOR, ^) 1751 ALU(MUL, *) 1752 SHT(LSH, <<) 1753 SHT(RSH, >>) 1754 #undef SHT 1755 #undef ALU 1756 ALU_NEG: 1757 DST = (u32) -DST; 1758 CONT; 1759 ALU64_NEG: 1760 DST = -DST; 1761 CONT; 1762 ALU_MOV_X: 1763 DST = (u32) SRC; 1764 CONT; 1765 ALU_MOV_K: 1766 DST = (u32) IMM; 1767 CONT; 1768 ALU64_MOV_X: 1769 DST = SRC; 1770 CONT; 1771 ALU64_MOV_K: 1772 DST = IMM; 1773 CONT; 1774 LD_IMM_DW: 1775 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1776 insn++; 1777 CONT; 1778 ALU_ARSH_X: 1779 DST = (u64) (u32) (((s32) DST) >> (SRC & 31)); 1780 CONT; 1781 ALU_ARSH_K: 1782 DST = (u64) (u32) (((s32) DST) >> IMM); 1783 CONT; 1784 ALU64_ARSH_X: 1785 (*(s64 *) &DST) >>= (SRC & 63); 1786 CONT; 1787 ALU64_ARSH_K: 1788 (*(s64 *) &DST) >>= IMM; 1789 CONT; 1790 ALU64_MOD_X: 1791 div64_u64_rem(DST, SRC, &AX); 1792 DST = AX; 1793 CONT; 1794 ALU_MOD_X: 1795 AX = (u32) DST; 1796 DST = do_div(AX, (u32) SRC); 1797 CONT; 1798 ALU64_MOD_K: 1799 div64_u64_rem(DST, IMM, &AX); 1800 DST = AX; 1801 CONT; 1802 ALU_MOD_K: 1803 AX = (u32) DST; 1804 DST = do_div(AX, (u32) IMM); 1805 CONT; 1806 ALU64_DIV_X: 1807 DST = div64_u64(DST, SRC); 1808 CONT; 1809 ALU_DIV_X: 1810 AX = (u32) DST; 1811 do_div(AX, (u32) SRC); 1812 DST = (u32) AX; 1813 CONT; 1814 ALU64_DIV_K: 1815 DST = div64_u64(DST, IMM); 1816 CONT; 1817 ALU_DIV_K: 1818 AX = (u32) DST; 1819 do_div(AX, (u32) IMM); 1820 DST = (u32) AX; 1821 CONT; 1822 ALU_END_TO_BE: 1823 switch (IMM) { 1824 case 16: 1825 DST = (__force u16) cpu_to_be16(DST); 1826 break; 1827 case 32: 1828 DST = (__force u32) cpu_to_be32(DST); 1829 break; 1830 case 64: 1831 DST = (__force u64) cpu_to_be64(DST); 1832 break; 1833 } 1834 CONT; 1835 ALU_END_TO_LE: 1836 switch (IMM) { 1837 case 16: 1838 DST = (__force u16) cpu_to_le16(DST); 1839 break; 1840 case 32: 1841 DST = (__force u32) cpu_to_le32(DST); 1842 break; 1843 case 64: 1844 DST = (__force u64) cpu_to_le64(DST); 1845 break; 1846 } 1847 CONT; 1848 1849 /* CALL */ 1850 JMP_CALL: 1851 /* Function call scratches BPF_R1-BPF_R5 registers, 1852 * preserves BPF_R6-BPF_R9, and stores return value 1853 * into BPF_R0. 1854 */ 1855 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1856 BPF_R4, BPF_R5); 1857 CONT; 1858 1859 JMP_CALL_ARGS: 1860 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 1861 BPF_R3, BPF_R4, 1862 BPF_R5, 1863 insn + insn->off + 1); 1864 CONT; 1865 1866 JMP_TAIL_CALL: { 1867 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1868 struct bpf_array *array = container_of(map, struct bpf_array, map); 1869 struct bpf_prog *prog; 1870 u32 index = BPF_R3; 1871 1872 if (unlikely(index >= array->map.max_entries)) 1873 goto out; 1874 1875 if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT)) 1876 goto out; 1877 1878 tail_call_cnt++; 1879 1880 prog = READ_ONCE(array->ptrs[index]); 1881 if (!prog) 1882 goto out; 1883 1884 /* ARG1 at this point is guaranteed to point to CTX from 1885 * the verifier side due to the fact that the tail call is 1886 * handled like a helper, that is, bpf_tail_call_proto, 1887 * where arg1_type is ARG_PTR_TO_CTX. 1888 */ 1889 insn = prog->insnsi; 1890 goto select_insn; 1891 out: 1892 CONT; 1893 } 1894 JMP_JA: 1895 insn += insn->off; 1896 CONT; 1897 JMP_EXIT: 1898 return BPF_R0; 1899 /* JMP */ 1900 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 1901 JMP_##OPCODE##_X: \ 1902 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 1903 insn += insn->off; \ 1904 CONT_JMP; \ 1905 } \ 1906 CONT; \ 1907 JMP32_##OPCODE##_X: \ 1908 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 1909 insn += insn->off; \ 1910 CONT_JMP; \ 1911 } \ 1912 CONT; \ 1913 JMP_##OPCODE##_K: \ 1914 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 1915 insn += insn->off; \ 1916 CONT_JMP; \ 1917 } \ 1918 CONT; \ 1919 JMP32_##OPCODE##_K: \ 1920 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 1921 insn += insn->off; \ 1922 CONT_JMP; \ 1923 } \ 1924 CONT; 1925 COND_JMP(u, JEQ, ==) 1926 COND_JMP(u, JNE, !=) 1927 COND_JMP(u, JGT, >) 1928 COND_JMP(u, JLT, <) 1929 COND_JMP(u, JGE, >=) 1930 COND_JMP(u, JLE, <=) 1931 COND_JMP(u, JSET, &) 1932 COND_JMP(s, JSGT, >) 1933 COND_JMP(s, JSLT, <) 1934 COND_JMP(s, JSGE, >=) 1935 COND_JMP(s, JSLE, <=) 1936 #undef COND_JMP 1937 /* ST, STX and LDX*/ 1938 ST_NOSPEC: 1939 /* Speculation barrier for mitigating Speculative Store Bypass. 1940 * In case of arm64, we rely on the firmware mitigation as 1941 * controlled via the ssbd kernel parameter. Whenever the 1942 * mitigation is enabled, it works for all of the kernel code 1943 * with no need to provide any additional instructions here. 1944 * In case of x86, we use 'lfence' insn for mitigation. We 1945 * reuse preexisting logic from Spectre v1 mitigation that 1946 * happens to produce the required code on x86 for v4 as well. 1947 */ 1948 #ifdef CONFIG_X86 1949 barrier_nospec(); 1950 #endif 1951 CONT; 1952 #define LDST(SIZEOP, SIZE) \ 1953 STX_MEM_##SIZEOP: \ 1954 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 1955 CONT; \ 1956 ST_MEM_##SIZEOP: \ 1957 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 1958 CONT; \ 1959 LDX_MEM_##SIZEOP: \ 1960 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 1961 CONT; \ 1962 LDX_PROBE_MEM_##SIZEOP: \ 1963 bpf_probe_read_kernel(&DST, sizeof(SIZE), \ 1964 (const void *)(long) (SRC + insn->off)); \ 1965 DST = *((SIZE *)&DST); \ 1966 CONT; 1967 1968 LDST(B, u8) 1969 LDST(H, u16) 1970 LDST(W, u32) 1971 LDST(DW, u64) 1972 #undef LDST 1973 1974 #define ATOMIC_ALU_OP(BOP, KOP) \ 1975 case BOP: \ 1976 if (BPF_SIZE(insn->code) == BPF_W) \ 1977 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \ 1978 (DST + insn->off)); \ 1979 else \ 1980 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \ 1981 (DST + insn->off)); \ 1982 break; \ 1983 case BOP | BPF_FETCH: \ 1984 if (BPF_SIZE(insn->code) == BPF_W) \ 1985 SRC = (u32) atomic_fetch_##KOP( \ 1986 (u32) SRC, \ 1987 (atomic_t *)(unsigned long) (DST + insn->off)); \ 1988 else \ 1989 SRC = (u64) atomic64_fetch_##KOP( \ 1990 (u64) SRC, \ 1991 (atomic64_t *)(unsigned long) (DST + insn->off)); \ 1992 break; 1993 1994 STX_ATOMIC_DW: 1995 STX_ATOMIC_W: 1996 switch (IMM) { 1997 ATOMIC_ALU_OP(BPF_ADD, add) 1998 ATOMIC_ALU_OP(BPF_AND, and) 1999 ATOMIC_ALU_OP(BPF_OR, or) 2000 ATOMIC_ALU_OP(BPF_XOR, xor) 2001 #undef ATOMIC_ALU_OP 2002 2003 case BPF_XCHG: 2004 if (BPF_SIZE(insn->code) == BPF_W) 2005 SRC = (u32) atomic_xchg( 2006 (atomic_t *)(unsigned long) (DST + insn->off), 2007 (u32) SRC); 2008 else 2009 SRC = (u64) atomic64_xchg( 2010 (atomic64_t *)(unsigned long) (DST + insn->off), 2011 (u64) SRC); 2012 break; 2013 case BPF_CMPXCHG: 2014 if (BPF_SIZE(insn->code) == BPF_W) 2015 BPF_R0 = (u32) atomic_cmpxchg( 2016 (atomic_t *)(unsigned long) (DST + insn->off), 2017 (u32) BPF_R0, (u32) SRC); 2018 else 2019 BPF_R0 = (u64) atomic64_cmpxchg( 2020 (atomic64_t *)(unsigned long) (DST + insn->off), 2021 (u64) BPF_R0, (u64) SRC); 2022 break; 2023 2024 default: 2025 goto default_label; 2026 } 2027 CONT; 2028 2029 default_label: 2030 /* If we ever reach this, we have a bug somewhere. Die hard here 2031 * instead of just returning 0; we could be somewhere in a subprog, 2032 * so execution could continue otherwise which we do /not/ want. 2033 * 2034 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 2035 */ 2036 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n", 2037 insn->code, insn->imm); 2038 BUG_ON(1); 2039 return 0; 2040 } 2041 2042 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 2043 #define DEFINE_BPF_PROG_RUN(stack_size) \ 2044 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 2045 { \ 2046 u64 stack[stack_size / sizeof(u64)]; \ 2047 u64 regs[MAX_BPF_EXT_REG]; \ 2048 \ 2049 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2050 ARG1 = (u64) (unsigned long) ctx; \ 2051 return ___bpf_prog_run(regs, insn); \ 2052 } 2053 2054 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 2055 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 2056 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 2057 const struct bpf_insn *insn) \ 2058 { \ 2059 u64 stack[stack_size / sizeof(u64)]; \ 2060 u64 regs[MAX_BPF_EXT_REG]; \ 2061 \ 2062 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2063 BPF_R1 = r1; \ 2064 BPF_R2 = r2; \ 2065 BPF_R3 = r3; \ 2066 BPF_R4 = r4; \ 2067 BPF_R5 = r5; \ 2068 return ___bpf_prog_run(regs, insn); \ 2069 } 2070 2071 #define EVAL1(FN, X) FN(X) 2072 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 2073 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 2074 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 2075 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 2076 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 2077 2078 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 2079 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 2080 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 2081 2082 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 2083 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 2084 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 2085 2086 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 2087 2088 static unsigned int (*interpreters[])(const void *ctx, 2089 const struct bpf_insn *insn) = { 2090 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2091 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2092 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2093 }; 2094 #undef PROG_NAME_LIST 2095 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 2096 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 2097 const struct bpf_insn *insn) = { 2098 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2099 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2100 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2101 }; 2102 #undef PROG_NAME_LIST 2103 2104 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 2105 { 2106 stack_depth = max_t(u32, stack_depth, 1); 2107 insn->off = (s16) insn->imm; 2108 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 2109 __bpf_call_base_args; 2110 insn->code = BPF_JMP | BPF_CALL_ARGS; 2111 } 2112 2113 #else 2114 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 2115 const struct bpf_insn *insn) 2116 { 2117 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 2118 * is not working properly, so warn about it! 2119 */ 2120 WARN_ON_ONCE(1); 2121 return 0; 2122 } 2123 #endif 2124 2125 bool bpf_prog_map_compatible(struct bpf_map *map, 2126 const struct bpf_prog *fp) 2127 { 2128 bool ret; 2129 2130 if (fp->kprobe_override) 2131 return false; 2132 2133 spin_lock(&map->owner.lock); 2134 if (!map->owner.type) { 2135 /* There's no owner yet where we could check for 2136 * compatibility. 2137 */ 2138 map->owner.type = fp->type; 2139 map->owner.jited = fp->jited; 2140 map->owner.xdp_has_frags = fp->aux->xdp_has_frags; 2141 ret = true; 2142 } else { 2143 ret = map->owner.type == fp->type && 2144 map->owner.jited == fp->jited && 2145 map->owner.xdp_has_frags == fp->aux->xdp_has_frags; 2146 } 2147 spin_unlock(&map->owner.lock); 2148 2149 return ret; 2150 } 2151 2152 static int bpf_check_tail_call(const struct bpf_prog *fp) 2153 { 2154 struct bpf_prog_aux *aux = fp->aux; 2155 int i, ret = 0; 2156 2157 mutex_lock(&aux->used_maps_mutex); 2158 for (i = 0; i < aux->used_map_cnt; i++) { 2159 struct bpf_map *map = aux->used_maps[i]; 2160 2161 if (!map_type_contains_progs(map)) 2162 continue; 2163 2164 if (!bpf_prog_map_compatible(map, fp)) { 2165 ret = -EINVAL; 2166 goto out; 2167 } 2168 } 2169 2170 out: 2171 mutex_unlock(&aux->used_maps_mutex); 2172 return ret; 2173 } 2174 2175 static void bpf_prog_select_func(struct bpf_prog *fp) 2176 { 2177 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 2178 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 2179 2180 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 2181 #else 2182 fp->bpf_func = __bpf_prog_ret0_warn; 2183 #endif 2184 } 2185 2186 /** 2187 * bpf_prog_select_runtime - select exec runtime for BPF program 2188 * @fp: bpf_prog populated with BPF program 2189 * @err: pointer to error variable 2190 * 2191 * Try to JIT eBPF program, if JIT is not available, use interpreter. 2192 * The BPF program will be executed via bpf_prog_run() function. 2193 * 2194 * Return: the &fp argument along with &err set to 0 for success or 2195 * a negative errno code on failure 2196 */ 2197 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 2198 { 2199 /* In case of BPF to BPF calls, verifier did all the prep 2200 * work with regards to JITing, etc. 2201 */ 2202 bool jit_needed = false; 2203 2204 if (fp->bpf_func) 2205 goto finalize; 2206 2207 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || 2208 bpf_prog_has_kfunc_call(fp)) 2209 jit_needed = true; 2210 2211 bpf_prog_select_func(fp); 2212 2213 /* eBPF JITs can rewrite the program in case constant 2214 * blinding is active. However, in case of error during 2215 * blinding, bpf_int_jit_compile() must always return a 2216 * valid program, which in this case would simply not 2217 * be JITed, but falls back to the interpreter. 2218 */ 2219 if (!bpf_prog_is_dev_bound(fp->aux)) { 2220 *err = bpf_prog_alloc_jited_linfo(fp); 2221 if (*err) 2222 return fp; 2223 2224 fp = bpf_int_jit_compile(fp); 2225 bpf_prog_jit_attempt_done(fp); 2226 if (!fp->jited && jit_needed) { 2227 *err = -ENOTSUPP; 2228 return fp; 2229 } 2230 } else { 2231 *err = bpf_prog_offload_compile(fp); 2232 if (*err) 2233 return fp; 2234 } 2235 2236 finalize: 2237 bpf_prog_lock_ro(fp); 2238 2239 /* The tail call compatibility check can only be done at 2240 * this late stage as we need to determine, if we deal 2241 * with JITed or non JITed program concatenations and not 2242 * all eBPF JITs might immediately support all features. 2243 */ 2244 *err = bpf_check_tail_call(fp); 2245 2246 return fp; 2247 } 2248 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 2249 2250 static unsigned int __bpf_prog_ret1(const void *ctx, 2251 const struct bpf_insn *insn) 2252 { 2253 return 1; 2254 } 2255 2256 static struct bpf_prog_dummy { 2257 struct bpf_prog prog; 2258 } dummy_bpf_prog = { 2259 .prog = { 2260 .bpf_func = __bpf_prog_ret1, 2261 }, 2262 }; 2263 2264 struct bpf_empty_prog_array bpf_empty_prog_array = { 2265 .null_prog = NULL, 2266 }; 2267 EXPORT_SYMBOL(bpf_empty_prog_array); 2268 2269 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 2270 { 2271 if (prog_cnt) 2272 return kzalloc(sizeof(struct bpf_prog_array) + 2273 sizeof(struct bpf_prog_array_item) * 2274 (prog_cnt + 1), 2275 flags); 2276 2277 return &bpf_empty_prog_array.hdr; 2278 } 2279 2280 void bpf_prog_array_free(struct bpf_prog_array *progs) 2281 { 2282 if (!progs || progs == &bpf_empty_prog_array.hdr) 2283 return; 2284 kfree_rcu(progs, rcu); 2285 } 2286 2287 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu) 2288 { 2289 struct bpf_prog_array *progs; 2290 2291 progs = container_of(rcu, struct bpf_prog_array, rcu); 2292 kfree_rcu(progs, rcu); 2293 } 2294 2295 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs) 2296 { 2297 if (!progs || progs == &bpf_empty_prog_array.hdr) 2298 return; 2299 call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb); 2300 } 2301 2302 int bpf_prog_array_length(struct bpf_prog_array *array) 2303 { 2304 struct bpf_prog_array_item *item; 2305 u32 cnt = 0; 2306 2307 for (item = array->items; item->prog; item++) 2308 if (item->prog != &dummy_bpf_prog.prog) 2309 cnt++; 2310 return cnt; 2311 } 2312 2313 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 2314 { 2315 struct bpf_prog_array_item *item; 2316 2317 for (item = array->items; item->prog; item++) 2318 if (item->prog != &dummy_bpf_prog.prog) 2319 return false; 2320 return true; 2321 } 2322 2323 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 2324 u32 *prog_ids, 2325 u32 request_cnt) 2326 { 2327 struct bpf_prog_array_item *item; 2328 int i = 0; 2329 2330 for (item = array->items; item->prog; item++) { 2331 if (item->prog == &dummy_bpf_prog.prog) 2332 continue; 2333 prog_ids[i] = item->prog->aux->id; 2334 if (++i == request_cnt) { 2335 item++; 2336 break; 2337 } 2338 } 2339 2340 return !!(item->prog); 2341 } 2342 2343 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 2344 __u32 __user *prog_ids, u32 cnt) 2345 { 2346 unsigned long err = 0; 2347 bool nospc; 2348 u32 *ids; 2349 2350 /* users of this function are doing: 2351 * cnt = bpf_prog_array_length(); 2352 * if (cnt > 0) 2353 * bpf_prog_array_copy_to_user(..., cnt); 2354 * so below kcalloc doesn't need extra cnt > 0 check. 2355 */ 2356 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 2357 if (!ids) 2358 return -ENOMEM; 2359 nospc = bpf_prog_array_copy_core(array, ids, cnt); 2360 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 2361 kfree(ids); 2362 if (err) 2363 return -EFAULT; 2364 if (nospc) 2365 return -ENOSPC; 2366 return 0; 2367 } 2368 2369 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 2370 struct bpf_prog *old_prog) 2371 { 2372 struct bpf_prog_array_item *item; 2373 2374 for (item = array->items; item->prog; item++) 2375 if (item->prog == old_prog) { 2376 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 2377 break; 2378 } 2379 } 2380 2381 /** 2382 * bpf_prog_array_delete_safe_at() - Replaces the program at the given 2383 * index into the program array with 2384 * a dummy no-op program. 2385 * @array: a bpf_prog_array 2386 * @index: the index of the program to replace 2387 * 2388 * Skips over dummy programs, by not counting them, when calculating 2389 * the position of the program to replace. 2390 * 2391 * Return: 2392 * * 0 - Success 2393 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2394 * * -ENOENT - Index out of range 2395 */ 2396 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) 2397 { 2398 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); 2399 } 2400 2401 /** 2402 * bpf_prog_array_update_at() - Updates the program at the given index 2403 * into the program array. 2404 * @array: a bpf_prog_array 2405 * @index: the index of the program to update 2406 * @prog: the program to insert into the array 2407 * 2408 * Skips over dummy programs, by not counting them, when calculating 2409 * the position of the program to update. 2410 * 2411 * Return: 2412 * * 0 - Success 2413 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2414 * * -ENOENT - Index out of range 2415 */ 2416 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, 2417 struct bpf_prog *prog) 2418 { 2419 struct bpf_prog_array_item *item; 2420 2421 if (unlikely(index < 0)) 2422 return -EINVAL; 2423 2424 for (item = array->items; item->prog; item++) { 2425 if (item->prog == &dummy_bpf_prog.prog) 2426 continue; 2427 if (!index) { 2428 WRITE_ONCE(item->prog, prog); 2429 return 0; 2430 } 2431 index--; 2432 } 2433 return -ENOENT; 2434 } 2435 2436 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 2437 struct bpf_prog *exclude_prog, 2438 struct bpf_prog *include_prog, 2439 u64 bpf_cookie, 2440 struct bpf_prog_array **new_array) 2441 { 2442 int new_prog_cnt, carry_prog_cnt = 0; 2443 struct bpf_prog_array_item *existing, *new; 2444 struct bpf_prog_array *array; 2445 bool found_exclude = false; 2446 2447 /* Figure out how many existing progs we need to carry over to 2448 * the new array. 2449 */ 2450 if (old_array) { 2451 existing = old_array->items; 2452 for (; existing->prog; existing++) { 2453 if (existing->prog == exclude_prog) { 2454 found_exclude = true; 2455 continue; 2456 } 2457 if (existing->prog != &dummy_bpf_prog.prog) 2458 carry_prog_cnt++; 2459 if (existing->prog == include_prog) 2460 return -EEXIST; 2461 } 2462 } 2463 2464 if (exclude_prog && !found_exclude) 2465 return -ENOENT; 2466 2467 /* How many progs (not NULL) will be in the new array? */ 2468 new_prog_cnt = carry_prog_cnt; 2469 if (include_prog) 2470 new_prog_cnt += 1; 2471 2472 /* Do we have any prog (not NULL) in the new array? */ 2473 if (!new_prog_cnt) { 2474 *new_array = NULL; 2475 return 0; 2476 } 2477 2478 /* +1 as the end of prog_array is marked with NULL */ 2479 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2480 if (!array) 2481 return -ENOMEM; 2482 new = array->items; 2483 2484 /* Fill in the new prog array */ 2485 if (carry_prog_cnt) { 2486 existing = old_array->items; 2487 for (; existing->prog; existing++) { 2488 if (existing->prog == exclude_prog || 2489 existing->prog == &dummy_bpf_prog.prog) 2490 continue; 2491 2492 new->prog = existing->prog; 2493 new->bpf_cookie = existing->bpf_cookie; 2494 new++; 2495 } 2496 } 2497 if (include_prog) { 2498 new->prog = include_prog; 2499 new->bpf_cookie = bpf_cookie; 2500 new++; 2501 } 2502 new->prog = NULL; 2503 *new_array = array; 2504 return 0; 2505 } 2506 2507 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2508 u32 *prog_ids, u32 request_cnt, 2509 u32 *prog_cnt) 2510 { 2511 u32 cnt = 0; 2512 2513 if (array) 2514 cnt = bpf_prog_array_length(array); 2515 2516 *prog_cnt = cnt; 2517 2518 /* return early if user requested only program count or nothing to copy */ 2519 if (!request_cnt || !cnt) 2520 return 0; 2521 2522 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2523 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2524 : 0; 2525 } 2526 2527 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2528 struct bpf_map **used_maps, u32 len) 2529 { 2530 struct bpf_map *map; 2531 u32 i; 2532 2533 for (i = 0; i < len; i++) { 2534 map = used_maps[i]; 2535 if (map->ops->map_poke_untrack) 2536 map->ops->map_poke_untrack(map, aux); 2537 bpf_map_put(map); 2538 } 2539 } 2540 2541 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2542 { 2543 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2544 kfree(aux->used_maps); 2545 } 2546 2547 void __bpf_free_used_btfs(struct bpf_prog_aux *aux, 2548 struct btf_mod_pair *used_btfs, u32 len) 2549 { 2550 #ifdef CONFIG_BPF_SYSCALL 2551 struct btf_mod_pair *btf_mod; 2552 u32 i; 2553 2554 for (i = 0; i < len; i++) { 2555 btf_mod = &used_btfs[i]; 2556 if (btf_mod->module) 2557 module_put(btf_mod->module); 2558 btf_put(btf_mod->btf); 2559 } 2560 #endif 2561 } 2562 2563 static void bpf_free_used_btfs(struct bpf_prog_aux *aux) 2564 { 2565 __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt); 2566 kfree(aux->used_btfs); 2567 } 2568 2569 static void bpf_prog_free_deferred(struct work_struct *work) 2570 { 2571 struct bpf_prog_aux *aux; 2572 int i; 2573 2574 aux = container_of(work, struct bpf_prog_aux, work); 2575 #ifdef CONFIG_BPF_SYSCALL 2576 bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab); 2577 #endif 2578 #ifdef CONFIG_CGROUP_BPF 2579 if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID) 2580 bpf_cgroup_atype_put(aux->cgroup_atype); 2581 #endif 2582 bpf_free_used_maps(aux); 2583 bpf_free_used_btfs(aux); 2584 if (bpf_prog_is_dev_bound(aux)) 2585 bpf_prog_offload_destroy(aux->prog); 2586 #ifdef CONFIG_PERF_EVENTS 2587 if (aux->prog->has_callchain_buf) 2588 put_callchain_buffers(); 2589 #endif 2590 if (aux->dst_trampoline) 2591 bpf_trampoline_put(aux->dst_trampoline); 2592 for (i = 0; i < aux->func_cnt; i++) { 2593 /* We can just unlink the subprog poke descriptor table as 2594 * it was originally linked to the main program and is also 2595 * released along with it. 2596 */ 2597 aux->func[i]->aux->poke_tab = NULL; 2598 bpf_jit_free(aux->func[i]); 2599 } 2600 if (aux->func_cnt) { 2601 kfree(aux->func); 2602 bpf_prog_unlock_free(aux->prog); 2603 } else { 2604 bpf_jit_free(aux->prog); 2605 } 2606 } 2607 2608 void bpf_prog_free(struct bpf_prog *fp) 2609 { 2610 struct bpf_prog_aux *aux = fp->aux; 2611 2612 if (aux->dst_prog) 2613 bpf_prog_put(aux->dst_prog); 2614 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2615 schedule_work(&aux->work); 2616 } 2617 EXPORT_SYMBOL_GPL(bpf_prog_free); 2618 2619 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 2620 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2621 2622 void bpf_user_rnd_init_once(void) 2623 { 2624 prandom_init_once(&bpf_user_rnd_state); 2625 } 2626 2627 BPF_CALL_0(bpf_user_rnd_u32) 2628 { 2629 /* Should someone ever have the rather unwise idea to use some 2630 * of the registers passed into this function, then note that 2631 * this function is called from native eBPF and classic-to-eBPF 2632 * transformations. Register assignments from both sides are 2633 * different, f.e. classic always sets fn(ctx, A, X) here. 2634 */ 2635 struct rnd_state *state; 2636 u32 res; 2637 2638 state = &get_cpu_var(bpf_user_rnd_state); 2639 res = prandom_u32_state(state); 2640 put_cpu_var(bpf_user_rnd_state); 2641 2642 return res; 2643 } 2644 2645 BPF_CALL_0(bpf_get_raw_cpu_id) 2646 { 2647 return raw_smp_processor_id(); 2648 } 2649 2650 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2651 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2652 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2653 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2654 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2655 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2656 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2657 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak; 2658 const struct bpf_func_proto bpf_spin_lock_proto __weak; 2659 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 2660 const struct bpf_func_proto bpf_jiffies64_proto __weak; 2661 2662 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2663 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2664 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2665 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2666 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 2667 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak; 2668 2669 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2670 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2671 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2672 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2673 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 2674 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2675 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 2676 const struct bpf_func_proto bpf_snprintf_btf_proto __weak; 2677 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; 2678 const struct bpf_func_proto bpf_set_retval_proto __weak; 2679 const struct bpf_func_proto bpf_get_retval_proto __weak; 2680 2681 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2682 { 2683 return NULL; 2684 } 2685 2686 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void) 2687 { 2688 return NULL; 2689 } 2690 2691 u64 __weak 2692 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2693 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2694 { 2695 return -ENOTSUPP; 2696 } 2697 EXPORT_SYMBOL_GPL(bpf_event_output); 2698 2699 /* Always built-in helper functions. */ 2700 const struct bpf_func_proto bpf_tail_call_proto = { 2701 .func = NULL, 2702 .gpl_only = false, 2703 .ret_type = RET_VOID, 2704 .arg1_type = ARG_PTR_TO_CTX, 2705 .arg2_type = ARG_CONST_MAP_PTR, 2706 .arg3_type = ARG_ANYTHING, 2707 }; 2708 2709 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 2710 * It is encouraged to implement bpf_int_jit_compile() instead, so that 2711 * eBPF and implicitly also cBPF can get JITed! 2712 */ 2713 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 2714 { 2715 return prog; 2716 } 2717 2718 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 2719 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 2720 */ 2721 void __weak bpf_jit_compile(struct bpf_prog *prog) 2722 { 2723 } 2724 2725 bool __weak bpf_helper_changes_pkt_data(void *func) 2726 { 2727 return false; 2728 } 2729 2730 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 2731 * analysis code and wants explicit zero extension inserted by verifier. 2732 * Otherwise, return FALSE. 2733 * 2734 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if 2735 * you don't override this. JITs that don't want these extra insns can detect 2736 * them using insn_is_zext. 2737 */ 2738 bool __weak bpf_jit_needs_zext(void) 2739 { 2740 return false; 2741 } 2742 2743 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ 2744 bool __weak bpf_jit_supports_subprog_tailcalls(void) 2745 { 2746 return false; 2747 } 2748 2749 bool __weak bpf_jit_supports_kfunc_call(void) 2750 { 2751 return false; 2752 } 2753 2754 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 2755 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 2756 */ 2757 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 2758 int len) 2759 { 2760 return -EFAULT; 2761 } 2762 2763 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, 2764 void *addr1, void *addr2) 2765 { 2766 return -ENOTSUPP; 2767 } 2768 2769 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len) 2770 { 2771 return ERR_PTR(-ENOTSUPP); 2772 } 2773 2774 int __weak bpf_arch_text_invalidate(void *dst, size_t len) 2775 { 2776 return -ENOTSUPP; 2777 } 2778 2779 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 2780 EXPORT_SYMBOL(bpf_stats_enabled_key); 2781 2782 /* All definitions of tracepoints related to BPF. */ 2783 #define CREATE_TRACE_POINTS 2784 #include <linux/bpf_trace.h> 2785 2786 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 2787 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 2788