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 #include <linux/bpf_mem_alloc.h> 38 39 #include <asm/barrier.h> 40 #include <asm/unaligned.h> 41 42 /* Registers */ 43 #define BPF_R0 regs[BPF_REG_0] 44 #define BPF_R1 regs[BPF_REG_1] 45 #define BPF_R2 regs[BPF_REG_2] 46 #define BPF_R3 regs[BPF_REG_3] 47 #define BPF_R4 regs[BPF_REG_4] 48 #define BPF_R5 regs[BPF_REG_5] 49 #define BPF_R6 regs[BPF_REG_6] 50 #define BPF_R7 regs[BPF_REG_7] 51 #define BPF_R8 regs[BPF_REG_8] 52 #define BPF_R9 regs[BPF_REG_9] 53 #define BPF_R10 regs[BPF_REG_10] 54 55 /* Named registers */ 56 #define DST regs[insn->dst_reg] 57 #define SRC regs[insn->src_reg] 58 #define FP regs[BPF_REG_FP] 59 #define AX regs[BPF_REG_AX] 60 #define ARG1 regs[BPF_REG_ARG1] 61 #define CTX regs[BPF_REG_CTX] 62 #define IMM insn->imm 63 64 struct bpf_mem_alloc bpf_global_ma; 65 bool bpf_global_ma_set; 66 67 /* No hurry in this branch 68 * 69 * Exported for the bpf jit load helper. 70 */ 71 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 72 { 73 u8 *ptr = NULL; 74 75 if (k >= SKF_NET_OFF) { 76 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 77 } else if (k >= SKF_LL_OFF) { 78 if (unlikely(!skb_mac_header_was_set(skb))) 79 return NULL; 80 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 81 } 82 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 83 return ptr; 84 85 return NULL; 86 } 87 88 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags) 89 { 90 gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; 91 struct bpf_prog_aux *aux; 92 struct bpf_prog *fp; 93 94 size = round_up(size, PAGE_SIZE); 95 fp = __vmalloc(size, gfp_flags); 96 if (fp == NULL) 97 return NULL; 98 99 aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT | gfp_extra_flags); 100 if (aux == NULL) { 101 vfree(fp); 102 return NULL; 103 } 104 fp->active = alloc_percpu_gfp(int, GFP_KERNEL_ACCOUNT | gfp_extra_flags); 105 if (!fp->active) { 106 vfree(fp); 107 kfree(aux); 108 return NULL; 109 } 110 111 fp->pages = size / PAGE_SIZE; 112 fp->aux = aux; 113 fp->aux->prog = fp; 114 fp->jit_requested = ebpf_jit_enabled(); 115 fp->blinding_requested = bpf_jit_blinding_enabled(fp); 116 #ifdef CONFIG_CGROUP_BPF 117 aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID; 118 #endif 119 120 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); 121 mutex_init(&fp->aux->used_maps_mutex); 122 mutex_init(&fp->aux->dst_mutex); 123 124 return fp; 125 } 126 127 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 128 { 129 gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; 130 struct bpf_prog *prog; 131 int cpu; 132 133 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); 134 if (!prog) 135 return NULL; 136 137 prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); 138 if (!prog->stats) { 139 free_percpu(prog->active); 140 kfree(prog->aux); 141 vfree(prog); 142 return NULL; 143 } 144 145 for_each_possible_cpu(cpu) { 146 struct bpf_prog_stats *pstats; 147 148 pstats = per_cpu_ptr(prog->stats, cpu); 149 u64_stats_init(&pstats->syncp); 150 } 151 return prog; 152 } 153 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 154 155 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 156 { 157 if (!prog->aux->nr_linfo || !prog->jit_requested) 158 return 0; 159 160 prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo, 161 sizeof(*prog->aux->jited_linfo), 162 GFP_KERNEL_ACCOUNT | __GFP_NOWARN); 163 if (!prog->aux->jited_linfo) 164 return -ENOMEM; 165 166 return 0; 167 } 168 169 void bpf_prog_jit_attempt_done(struct bpf_prog *prog) 170 { 171 if (prog->aux->jited_linfo && 172 (!prog->jited || !prog->aux->jited_linfo[0])) { 173 kvfree(prog->aux->jited_linfo); 174 prog->aux->jited_linfo = NULL; 175 } 176 177 kfree(prog->aux->kfunc_tab); 178 prog->aux->kfunc_tab = NULL; 179 } 180 181 /* The jit engine is responsible to provide an array 182 * for insn_off to the jited_off mapping (insn_to_jit_off). 183 * 184 * The idx to this array is the insn_off. Hence, the insn_off 185 * here is relative to the prog itself instead of the main prog. 186 * This array has one entry for each xlated bpf insn. 187 * 188 * jited_off is the byte off to the end of the jited insn. 189 * 190 * Hence, with 191 * insn_start: 192 * The first bpf insn off of the prog. The insn off 193 * here is relative to the main prog. 194 * e.g. if prog is a subprog, insn_start > 0 195 * linfo_idx: 196 * The prog's idx to prog->aux->linfo and jited_linfo 197 * 198 * jited_linfo[linfo_idx] = prog->bpf_func 199 * 200 * For i > linfo_idx, 201 * 202 * jited_linfo[i] = prog->bpf_func + 203 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 204 */ 205 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 206 const u32 *insn_to_jit_off) 207 { 208 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 209 const struct bpf_line_info *linfo; 210 void **jited_linfo; 211 212 if (!prog->aux->jited_linfo) 213 /* Userspace did not provide linfo */ 214 return; 215 216 linfo_idx = prog->aux->linfo_idx; 217 linfo = &prog->aux->linfo[linfo_idx]; 218 insn_start = linfo[0].insn_off; 219 insn_end = insn_start + prog->len; 220 221 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 222 jited_linfo[0] = prog->bpf_func; 223 224 nr_linfo = prog->aux->nr_linfo - linfo_idx; 225 226 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 227 /* The verifier ensures that linfo[i].insn_off is 228 * strictly increasing 229 */ 230 jited_linfo[i] = prog->bpf_func + 231 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 232 } 233 234 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 235 gfp_t gfp_extra_flags) 236 { 237 gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags; 238 struct bpf_prog *fp; 239 u32 pages; 240 241 size = round_up(size, PAGE_SIZE); 242 pages = size / PAGE_SIZE; 243 if (pages <= fp_old->pages) 244 return fp_old; 245 246 fp = __vmalloc(size, gfp_flags); 247 if (fp) { 248 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 249 fp->pages = pages; 250 fp->aux->prog = fp; 251 252 /* We keep fp->aux from fp_old around in the new 253 * reallocated structure. 254 */ 255 fp_old->aux = NULL; 256 fp_old->stats = NULL; 257 fp_old->active = NULL; 258 __bpf_prog_free(fp_old); 259 } 260 261 return fp; 262 } 263 264 void __bpf_prog_free(struct bpf_prog *fp) 265 { 266 if (fp->aux) { 267 mutex_destroy(&fp->aux->used_maps_mutex); 268 mutex_destroy(&fp->aux->dst_mutex); 269 kfree(fp->aux->poke_tab); 270 kfree(fp->aux); 271 } 272 free_percpu(fp->stats); 273 free_percpu(fp->active); 274 vfree(fp); 275 } 276 277 int bpf_prog_calc_tag(struct bpf_prog *fp) 278 { 279 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64); 280 u32 raw_size = bpf_prog_tag_scratch_size(fp); 281 u32 digest[SHA1_DIGEST_WORDS]; 282 u32 ws[SHA1_WORKSPACE_WORDS]; 283 u32 i, bsize, psize, blocks; 284 struct bpf_insn *dst; 285 bool was_ld_map; 286 u8 *raw, *todo; 287 __be32 *result; 288 __be64 *bits; 289 290 raw = vmalloc(raw_size); 291 if (!raw) 292 return -ENOMEM; 293 294 sha1_init(digest); 295 memset(ws, 0, sizeof(ws)); 296 297 /* We need to take out the map fd for the digest calculation 298 * since they are unstable from user space side. 299 */ 300 dst = (void *)raw; 301 for (i = 0, was_ld_map = false; i < fp->len; i++) { 302 dst[i] = fp->insnsi[i]; 303 if (!was_ld_map && 304 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 305 (dst[i].src_reg == BPF_PSEUDO_MAP_FD || 306 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { 307 was_ld_map = true; 308 dst[i].imm = 0; 309 } else if (was_ld_map && 310 dst[i].code == 0 && 311 dst[i].dst_reg == 0 && 312 dst[i].src_reg == 0 && 313 dst[i].off == 0) { 314 was_ld_map = false; 315 dst[i].imm = 0; 316 } else { 317 was_ld_map = false; 318 } 319 } 320 321 psize = bpf_prog_insn_size(fp); 322 memset(&raw[psize], 0, raw_size - psize); 323 raw[psize++] = 0x80; 324 325 bsize = round_up(psize, SHA1_BLOCK_SIZE); 326 blocks = bsize / SHA1_BLOCK_SIZE; 327 todo = raw; 328 if (bsize - psize >= sizeof(__be64)) { 329 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 330 } else { 331 bits = (__be64 *)(todo + bsize + bits_offset); 332 blocks++; 333 } 334 *bits = cpu_to_be64((psize - 1) << 3); 335 336 while (blocks--) { 337 sha1_transform(digest, todo, ws); 338 todo += SHA1_BLOCK_SIZE; 339 } 340 341 result = (__force __be32 *)digest; 342 for (i = 0; i < SHA1_DIGEST_WORDS; i++) 343 result[i] = cpu_to_be32(digest[i]); 344 memcpy(fp->tag, result, sizeof(fp->tag)); 345 346 vfree(raw); 347 return 0; 348 } 349 350 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, 351 s32 end_new, s32 curr, const bool probe_pass) 352 { 353 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 354 s32 delta = end_new - end_old; 355 s64 imm = insn->imm; 356 357 if (curr < pos && curr + imm + 1 >= end_old) 358 imm += delta; 359 else if (curr >= end_new && curr + imm + 1 < end_new) 360 imm -= delta; 361 if (imm < imm_min || imm > imm_max) 362 return -ERANGE; 363 if (!probe_pass) 364 insn->imm = imm; 365 return 0; 366 } 367 368 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, 369 s32 end_new, s32 curr, const bool probe_pass) 370 { 371 const s32 off_min = S16_MIN, off_max = S16_MAX; 372 s32 delta = end_new - end_old; 373 s32 off = insn->off; 374 375 if (curr < pos && curr + off + 1 >= end_old) 376 off += delta; 377 else if (curr >= end_new && curr + off + 1 < end_new) 378 off -= delta; 379 if (off < off_min || off > off_max) 380 return -ERANGE; 381 if (!probe_pass) 382 insn->off = off; 383 return 0; 384 } 385 386 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 387 s32 end_new, const bool probe_pass) 388 { 389 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); 390 struct bpf_insn *insn = prog->insnsi; 391 int ret = 0; 392 393 for (i = 0; i < insn_cnt; i++, insn++) { 394 u8 code; 395 396 /* In the probing pass we still operate on the original, 397 * unpatched image in order to check overflows before we 398 * do any other adjustments. Therefore skip the patchlet. 399 */ 400 if (probe_pass && i == pos) { 401 i = end_new; 402 insn = prog->insnsi + end_old; 403 } 404 if (bpf_pseudo_func(insn)) { 405 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 406 end_new, i, probe_pass); 407 if (ret) 408 return ret; 409 continue; 410 } 411 code = insn->code; 412 if ((BPF_CLASS(code) != BPF_JMP && 413 BPF_CLASS(code) != BPF_JMP32) || 414 BPF_OP(code) == BPF_EXIT) 415 continue; 416 /* Adjust offset of jmps if we cross patch boundaries. */ 417 if (BPF_OP(code) == BPF_CALL) { 418 if (insn->src_reg != BPF_PSEUDO_CALL) 419 continue; 420 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 421 end_new, i, probe_pass); 422 } else { 423 ret = bpf_adj_delta_to_off(insn, pos, end_old, 424 end_new, i, probe_pass); 425 } 426 if (ret) 427 break; 428 } 429 430 return ret; 431 } 432 433 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 434 { 435 struct bpf_line_info *linfo; 436 u32 i, nr_linfo; 437 438 nr_linfo = prog->aux->nr_linfo; 439 if (!nr_linfo || !delta) 440 return; 441 442 linfo = prog->aux->linfo; 443 444 for (i = 0; i < nr_linfo; i++) 445 if (off < linfo[i].insn_off) 446 break; 447 448 /* Push all off < linfo[i].insn_off by delta */ 449 for (; i < nr_linfo; i++) 450 linfo[i].insn_off += delta; 451 } 452 453 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 454 const struct bpf_insn *patch, u32 len) 455 { 456 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 457 const u32 cnt_max = S16_MAX; 458 struct bpf_prog *prog_adj; 459 int err; 460 461 /* Since our patchlet doesn't expand the image, we're done. */ 462 if (insn_delta == 0) { 463 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 464 return prog; 465 } 466 467 insn_adj_cnt = prog->len + insn_delta; 468 469 /* Reject anything that would potentially let the insn->off 470 * target overflow when we have excessive program expansions. 471 * We need to probe here before we do any reallocation where 472 * we afterwards may not fail anymore. 473 */ 474 if (insn_adj_cnt > cnt_max && 475 (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) 476 return ERR_PTR(err); 477 478 /* Several new instructions need to be inserted. Make room 479 * for them. Likely, there's no need for a new allocation as 480 * last page could have large enough tailroom. 481 */ 482 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 483 GFP_USER); 484 if (!prog_adj) 485 return ERR_PTR(-ENOMEM); 486 487 prog_adj->len = insn_adj_cnt; 488 489 /* Patching happens in 3 steps: 490 * 491 * 1) Move over tail of insnsi from next instruction onwards, 492 * so we can patch the single target insn with one or more 493 * new ones (patching is always from 1 to n insns, n > 0). 494 * 2) Inject new instructions at the target location. 495 * 3) Adjust branch offsets if necessary. 496 */ 497 insn_rest = insn_adj_cnt - off - len; 498 499 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 500 sizeof(*patch) * insn_rest); 501 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 502 503 /* We are guaranteed to not fail at this point, otherwise 504 * the ship has sailed to reverse to the original state. An 505 * overflow cannot happen at this point. 506 */ 507 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); 508 509 bpf_adj_linfo(prog_adj, off, insn_delta); 510 511 return prog_adj; 512 } 513 514 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) 515 { 516 /* Branch offsets can't overflow when program is shrinking, no need 517 * to call bpf_adj_branches(..., true) here 518 */ 519 memmove(prog->insnsi + off, prog->insnsi + off + cnt, 520 sizeof(struct bpf_insn) * (prog->len - off - cnt)); 521 prog->len -= cnt; 522 523 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); 524 } 525 526 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 527 { 528 int i; 529 530 for (i = 0; i < fp->aux->func_cnt; i++) 531 bpf_prog_kallsyms_del(fp->aux->func[i]); 532 } 533 534 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 535 { 536 bpf_prog_kallsyms_del_subprogs(fp); 537 bpf_prog_kallsyms_del(fp); 538 } 539 540 #ifdef CONFIG_BPF_JIT 541 /* All BPF JIT sysctl knobs here. */ 542 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 543 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 544 int bpf_jit_harden __read_mostly; 545 long bpf_jit_limit __read_mostly; 546 long bpf_jit_limit_max __read_mostly; 547 548 static void 549 bpf_prog_ksym_set_addr(struct bpf_prog *prog) 550 { 551 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 552 553 prog->aux->ksym.start = (unsigned long) prog->bpf_func; 554 prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len; 555 } 556 557 static void 558 bpf_prog_ksym_set_name(struct bpf_prog *prog) 559 { 560 char *sym = prog->aux->ksym.name; 561 const char *end = sym + KSYM_NAME_LEN; 562 const struct btf_type *type; 563 const char *func_name; 564 565 BUILD_BUG_ON(sizeof("bpf_prog_") + 566 sizeof(prog->tag) * 2 + 567 /* name has been null terminated. 568 * We should need +1 for the '_' preceding 569 * the name. However, the null character 570 * is double counted between the name and the 571 * sizeof("bpf_prog_") above, so we omit 572 * the +1 here. 573 */ 574 sizeof(prog->aux->name) > KSYM_NAME_LEN); 575 576 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 577 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 578 579 /* prog->aux->name will be ignored if full btf name is available */ 580 if (prog->aux->func_info_cnt) { 581 type = btf_type_by_id(prog->aux->btf, 582 prog->aux->func_info[prog->aux->func_idx].type_id); 583 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 584 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 585 return; 586 } 587 588 if (prog->aux->name[0]) 589 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 590 else 591 *sym = 0; 592 } 593 594 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) 595 { 596 return container_of(n, struct bpf_ksym, tnode)->start; 597 } 598 599 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 600 struct latch_tree_node *b) 601 { 602 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); 603 } 604 605 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 606 { 607 unsigned long val = (unsigned long)key; 608 const struct bpf_ksym *ksym; 609 610 ksym = container_of(n, struct bpf_ksym, tnode); 611 612 if (val < ksym->start) 613 return -1; 614 if (val >= ksym->end) 615 return 1; 616 617 return 0; 618 } 619 620 static const struct latch_tree_ops bpf_tree_ops = { 621 .less = bpf_tree_less, 622 .comp = bpf_tree_comp, 623 }; 624 625 static DEFINE_SPINLOCK(bpf_lock); 626 static LIST_HEAD(bpf_kallsyms); 627 static struct latch_tree_root bpf_tree __cacheline_aligned; 628 629 void bpf_ksym_add(struct bpf_ksym *ksym) 630 { 631 spin_lock_bh(&bpf_lock); 632 WARN_ON_ONCE(!list_empty(&ksym->lnode)); 633 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); 634 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 635 spin_unlock_bh(&bpf_lock); 636 } 637 638 static void __bpf_ksym_del(struct bpf_ksym *ksym) 639 { 640 if (list_empty(&ksym->lnode)) 641 return; 642 643 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 644 list_del_rcu(&ksym->lnode); 645 } 646 647 void bpf_ksym_del(struct bpf_ksym *ksym) 648 { 649 spin_lock_bh(&bpf_lock); 650 __bpf_ksym_del(ksym); 651 spin_unlock_bh(&bpf_lock); 652 } 653 654 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 655 { 656 return fp->jited && !bpf_prog_was_classic(fp); 657 } 658 659 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 660 { 661 if (!bpf_prog_kallsyms_candidate(fp) || 662 !bpf_capable()) 663 return; 664 665 bpf_prog_ksym_set_addr(fp); 666 bpf_prog_ksym_set_name(fp); 667 fp->aux->ksym.prog = true; 668 669 bpf_ksym_add(&fp->aux->ksym); 670 } 671 672 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 673 { 674 if (!bpf_prog_kallsyms_candidate(fp)) 675 return; 676 677 bpf_ksym_del(&fp->aux->ksym); 678 } 679 680 static struct bpf_ksym *bpf_ksym_find(unsigned long addr) 681 { 682 struct latch_tree_node *n; 683 684 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 685 return n ? container_of(n, struct bpf_ksym, tnode) : NULL; 686 } 687 688 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, 689 unsigned long *off, char *sym) 690 { 691 struct bpf_ksym *ksym; 692 char *ret = NULL; 693 694 rcu_read_lock(); 695 ksym = bpf_ksym_find(addr); 696 if (ksym) { 697 unsigned long symbol_start = ksym->start; 698 unsigned long symbol_end = ksym->end; 699 700 strncpy(sym, ksym->name, KSYM_NAME_LEN); 701 702 ret = sym; 703 if (size) 704 *size = symbol_end - symbol_start; 705 if (off) 706 *off = addr - symbol_start; 707 } 708 rcu_read_unlock(); 709 710 return ret; 711 } 712 713 bool is_bpf_text_address(unsigned long addr) 714 { 715 bool ret; 716 717 rcu_read_lock(); 718 ret = bpf_ksym_find(addr) != NULL; 719 rcu_read_unlock(); 720 721 return ret; 722 } 723 724 static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) 725 { 726 struct bpf_ksym *ksym = bpf_ksym_find(addr); 727 728 return ksym && ksym->prog ? 729 container_of(ksym, struct bpf_prog_aux, ksym)->prog : 730 NULL; 731 } 732 733 const struct exception_table_entry *search_bpf_extables(unsigned long addr) 734 { 735 const struct exception_table_entry *e = NULL; 736 struct bpf_prog *prog; 737 738 rcu_read_lock(); 739 prog = bpf_prog_ksym_find(addr); 740 if (!prog) 741 goto out; 742 if (!prog->aux->num_exentries) 743 goto out; 744 745 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); 746 out: 747 rcu_read_unlock(); 748 return e; 749 } 750 751 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 752 char *sym) 753 { 754 struct bpf_ksym *ksym; 755 unsigned int it = 0; 756 int ret = -ERANGE; 757 758 if (!bpf_jit_kallsyms_enabled()) 759 return ret; 760 761 rcu_read_lock(); 762 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { 763 if (it++ != symnum) 764 continue; 765 766 strncpy(sym, ksym->name, KSYM_NAME_LEN); 767 768 *value = ksym->start; 769 *type = BPF_SYM_ELF_TYPE; 770 771 ret = 0; 772 break; 773 } 774 rcu_read_unlock(); 775 776 return ret; 777 } 778 779 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, 780 struct bpf_jit_poke_descriptor *poke) 781 { 782 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; 783 static const u32 poke_tab_max = 1024; 784 u32 slot = prog->aux->size_poke_tab; 785 u32 size = slot + 1; 786 787 if (size > poke_tab_max) 788 return -ENOSPC; 789 if (poke->tailcall_target || poke->tailcall_target_stable || 790 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) 791 return -EINVAL; 792 793 switch (poke->reason) { 794 case BPF_POKE_REASON_TAIL_CALL: 795 if (!poke->tail_call.map) 796 return -EINVAL; 797 break; 798 default: 799 return -EINVAL; 800 } 801 802 tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL); 803 if (!tab) 804 return -ENOMEM; 805 806 memcpy(&tab[slot], poke, sizeof(*poke)); 807 prog->aux->size_poke_tab = size; 808 prog->aux->poke_tab = tab; 809 810 return slot; 811 } 812 813 /* 814 * BPF program pack allocator. 815 * 816 * Most BPF programs are pretty small. Allocating a hole page for each 817 * program is sometime a waste. Many small bpf program also adds pressure 818 * to instruction TLB. To solve this issue, we introduce a BPF program pack 819 * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86) 820 * to host BPF programs. 821 */ 822 #define BPF_PROG_CHUNK_SHIFT 6 823 #define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT) 824 #define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1)) 825 826 struct bpf_prog_pack { 827 struct list_head list; 828 void *ptr; 829 unsigned long bitmap[]; 830 }; 831 832 void bpf_jit_fill_hole_with_zero(void *area, unsigned int size) 833 { 834 memset(area, 0, size); 835 } 836 837 #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) 838 839 static DEFINE_MUTEX(pack_mutex); 840 static LIST_HEAD(pack_list); 841 842 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with 843 * CONFIG_MMU=n. Use PAGE_SIZE in these cases. 844 */ 845 #ifdef PMD_SIZE 846 #define BPF_PROG_PACK_SIZE (PMD_SIZE * num_possible_nodes()) 847 #else 848 #define BPF_PROG_PACK_SIZE PAGE_SIZE 849 #endif 850 851 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE) 852 853 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) 854 { 855 struct bpf_prog_pack *pack; 856 857 pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)), 858 GFP_KERNEL); 859 if (!pack) 860 return NULL; 861 pack->ptr = module_alloc(BPF_PROG_PACK_SIZE); 862 if (!pack->ptr) { 863 kfree(pack); 864 return NULL; 865 } 866 bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE); 867 bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE); 868 list_add_tail(&pack->list, &pack_list); 869 870 set_vm_flush_reset_perms(pack->ptr); 871 set_memory_ro((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); 872 set_memory_x((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); 873 return pack; 874 } 875 876 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) 877 { 878 unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); 879 struct bpf_prog_pack *pack; 880 unsigned long pos; 881 void *ptr = NULL; 882 883 mutex_lock(&pack_mutex); 884 if (size > BPF_PROG_PACK_SIZE) { 885 size = round_up(size, PAGE_SIZE); 886 ptr = module_alloc(size); 887 if (ptr) { 888 bpf_fill_ill_insns(ptr, size); 889 set_vm_flush_reset_perms(ptr); 890 set_memory_ro((unsigned long)ptr, size / PAGE_SIZE); 891 set_memory_x((unsigned long)ptr, size / PAGE_SIZE); 892 } 893 goto out; 894 } 895 list_for_each_entry(pack, &pack_list, list) { 896 pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 897 nbits, 0); 898 if (pos < BPF_PROG_CHUNK_COUNT) 899 goto found_free_area; 900 } 901 902 pack = alloc_new_pack(bpf_fill_ill_insns); 903 if (!pack) 904 goto out; 905 906 pos = 0; 907 908 found_free_area: 909 bitmap_set(pack->bitmap, pos, nbits); 910 ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT); 911 912 out: 913 mutex_unlock(&pack_mutex); 914 return ptr; 915 } 916 917 void bpf_prog_pack_free(struct bpf_binary_header *hdr) 918 { 919 struct bpf_prog_pack *pack = NULL, *tmp; 920 unsigned int nbits; 921 unsigned long pos; 922 923 mutex_lock(&pack_mutex); 924 if (hdr->size > BPF_PROG_PACK_SIZE) { 925 module_memfree(hdr); 926 goto out; 927 } 928 929 list_for_each_entry(tmp, &pack_list, list) { 930 if ((void *)hdr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > (void *)hdr) { 931 pack = tmp; 932 break; 933 } 934 } 935 936 if (WARN_ONCE(!pack, "bpf_prog_pack bug\n")) 937 goto out; 938 939 nbits = BPF_PROG_SIZE_TO_NBITS(hdr->size); 940 pos = ((unsigned long)hdr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT; 941 942 WARN_ONCE(bpf_arch_text_invalidate(hdr, hdr->size), 943 "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n"); 944 945 bitmap_clear(pack->bitmap, pos, nbits); 946 if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 947 BPF_PROG_CHUNK_COUNT, 0) == 0) { 948 list_del(&pack->list); 949 module_memfree(pack->ptr); 950 kfree(pack); 951 } 952 out: 953 mutex_unlock(&pack_mutex); 954 } 955 956 static atomic_long_t bpf_jit_current; 957 958 /* Can be overridden by an arch's JIT compiler if it has a custom, 959 * dedicated BPF backend memory area, or if neither of the two 960 * below apply. 961 */ 962 u64 __weak bpf_jit_alloc_exec_limit(void) 963 { 964 #if defined(MODULES_VADDR) 965 return MODULES_END - MODULES_VADDR; 966 #else 967 return VMALLOC_END - VMALLOC_START; 968 #endif 969 } 970 971 static int __init bpf_jit_charge_init(void) 972 { 973 /* Only used as heuristic here to derive limit. */ 974 bpf_jit_limit_max = bpf_jit_alloc_exec_limit(); 975 bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 2, 976 PAGE_SIZE), LONG_MAX); 977 return 0; 978 } 979 pure_initcall(bpf_jit_charge_init); 980 981 int bpf_jit_charge_modmem(u32 size) 982 { 983 if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) { 984 if (!bpf_capable()) { 985 atomic_long_sub(size, &bpf_jit_current); 986 return -EPERM; 987 } 988 } 989 990 return 0; 991 } 992 993 void bpf_jit_uncharge_modmem(u32 size) 994 { 995 atomic_long_sub(size, &bpf_jit_current); 996 } 997 998 void *__weak bpf_jit_alloc_exec(unsigned long size) 999 { 1000 return module_alloc(size); 1001 } 1002 1003 void __weak bpf_jit_free_exec(void *addr) 1004 { 1005 module_memfree(addr); 1006 } 1007 1008 struct bpf_binary_header * 1009 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 1010 unsigned int alignment, 1011 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1012 { 1013 struct bpf_binary_header *hdr; 1014 u32 size, hole, start; 1015 1016 WARN_ON_ONCE(!is_power_of_2(alignment) || 1017 alignment > BPF_IMAGE_ALIGNMENT); 1018 1019 /* Most of BPF filters are really small, but if some of them 1020 * fill a page, allow at least 128 extra bytes to insert a 1021 * random section of illegal instructions. 1022 */ 1023 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 1024 1025 if (bpf_jit_charge_modmem(size)) 1026 return NULL; 1027 hdr = bpf_jit_alloc_exec(size); 1028 if (!hdr) { 1029 bpf_jit_uncharge_modmem(size); 1030 return NULL; 1031 } 1032 1033 /* Fill space with illegal/arch-dep instructions. */ 1034 bpf_fill_ill_insns(hdr, size); 1035 1036 hdr->size = size; 1037 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 1038 PAGE_SIZE - sizeof(*hdr)); 1039 start = prandom_u32_max(hole) & ~(alignment - 1); 1040 1041 /* Leave a random number of instructions before BPF code. */ 1042 *image_ptr = &hdr->image[start]; 1043 1044 return hdr; 1045 } 1046 1047 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 1048 { 1049 u32 size = hdr->size; 1050 1051 bpf_jit_free_exec(hdr); 1052 bpf_jit_uncharge_modmem(size); 1053 } 1054 1055 /* Allocate jit binary from bpf_prog_pack allocator. 1056 * Since the allocated memory is RO+X, the JIT engine cannot write directly 1057 * to the memory. To solve this problem, a RW buffer is also allocated at 1058 * as the same time. The JIT engine should calculate offsets based on the 1059 * RO memory address, but write JITed program to the RW buffer. Once the 1060 * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies 1061 * the JITed program to the RO memory. 1062 */ 1063 struct bpf_binary_header * 1064 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr, 1065 unsigned int alignment, 1066 struct bpf_binary_header **rw_header, 1067 u8 **rw_image, 1068 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1069 { 1070 struct bpf_binary_header *ro_header; 1071 u32 size, hole, start; 1072 1073 WARN_ON_ONCE(!is_power_of_2(alignment) || 1074 alignment > BPF_IMAGE_ALIGNMENT); 1075 1076 /* add 16 bytes for a random section of illegal instructions */ 1077 size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE); 1078 1079 if (bpf_jit_charge_modmem(size)) 1080 return NULL; 1081 ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns); 1082 if (!ro_header) { 1083 bpf_jit_uncharge_modmem(size); 1084 return NULL; 1085 } 1086 1087 *rw_header = kvmalloc(size, GFP_KERNEL); 1088 if (!*rw_header) { 1089 bpf_arch_text_copy(&ro_header->size, &size, sizeof(size)); 1090 bpf_prog_pack_free(ro_header); 1091 bpf_jit_uncharge_modmem(size); 1092 return NULL; 1093 } 1094 1095 /* Fill space with illegal/arch-dep instructions. */ 1096 bpf_fill_ill_insns(*rw_header, size); 1097 (*rw_header)->size = size; 1098 1099 hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)), 1100 BPF_PROG_CHUNK_SIZE - sizeof(*ro_header)); 1101 start = prandom_u32_max(hole) & ~(alignment - 1); 1102 1103 *image_ptr = &ro_header->image[start]; 1104 *rw_image = &(*rw_header)->image[start]; 1105 1106 return ro_header; 1107 } 1108 1109 /* Copy JITed text from rw_header to its final location, the ro_header. */ 1110 int bpf_jit_binary_pack_finalize(struct bpf_prog *prog, 1111 struct bpf_binary_header *ro_header, 1112 struct bpf_binary_header *rw_header) 1113 { 1114 void *ptr; 1115 1116 ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size); 1117 1118 kvfree(rw_header); 1119 1120 if (IS_ERR(ptr)) { 1121 bpf_prog_pack_free(ro_header); 1122 return PTR_ERR(ptr); 1123 } 1124 return 0; 1125 } 1126 1127 /* bpf_jit_binary_pack_free is called in two different scenarios: 1128 * 1) when the program is freed after; 1129 * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize). 1130 * For case 2), we need to free both the RO memory and the RW buffer. 1131 * 1132 * bpf_jit_binary_pack_free requires proper ro_header->size. However, 1133 * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size 1134 * must be set with either bpf_jit_binary_pack_finalize (normal path) or 1135 * bpf_arch_text_copy (when jit fails). 1136 */ 1137 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header, 1138 struct bpf_binary_header *rw_header) 1139 { 1140 u32 size = ro_header->size; 1141 1142 bpf_prog_pack_free(ro_header); 1143 kvfree(rw_header); 1144 bpf_jit_uncharge_modmem(size); 1145 } 1146 1147 struct bpf_binary_header * 1148 bpf_jit_binary_pack_hdr(const struct bpf_prog *fp) 1149 { 1150 unsigned long real_start = (unsigned long)fp->bpf_func; 1151 unsigned long addr; 1152 1153 addr = real_start & BPF_PROG_CHUNK_MASK; 1154 return (void *)addr; 1155 } 1156 1157 static inline struct bpf_binary_header * 1158 bpf_jit_binary_hdr(const struct bpf_prog *fp) 1159 { 1160 unsigned long real_start = (unsigned long)fp->bpf_func; 1161 unsigned long addr; 1162 1163 addr = real_start & PAGE_MASK; 1164 return (void *)addr; 1165 } 1166 1167 /* This symbol is only overridden by archs that have different 1168 * requirements than the usual eBPF JITs, f.e. when they only 1169 * implement cBPF JIT, do not set images read-only, etc. 1170 */ 1171 void __weak bpf_jit_free(struct bpf_prog *fp) 1172 { 1173 if (fp->jited) { 1174 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 1175 1176 bpf_jit_binary_free(hdr); 1177 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 1178 } 1179 1180 bpf_prog_unlock_free(fp); 1181 } 1182 1183 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 1184 const struct bpf_insn *insn, bool extra_pass, 1185 u64 *func_addr, bool *func_addr_fixed) 1186 { 1187 s16 off = insn->off; 1188 s32 imm = insn->imm; 1189 u8 *addr; 1190 1191 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 1192 if (!*func_addr_fixed) { 1193 /* Place-holder address till the last pass has collected 1194 * all addresses for JITed subprograms in which case we 1195 * can pick them up from prog->aux. 1196 */ 1197 if (!extra_pass) 1198 addr = NULL; 1199 else if (prog->aux->func && 1200 off >= 0 && off < prog->aux->func_cnt) 1201 addr = (u8 *)prog->aux->func[off]->bpf_func; 1202 else 1203 return -EINVAL; 1204 } else { 1205 /* Address of a BPF helper call. Since part of the core 1206 * kernel, it's always at a fixed location. __bpf_call_base 1207 * and the helper with imm relative to it are both in core 1208 * kernel. 1209 */ 1210 addr = (u8 *)__bpf_call_base + imm; 1211 } 1212 1213 *func_addr = (unsigned long)addr; 1214 return 0; 1215 } 1216 1217 static int bpf_jit_blind_insn(const struct bpf_insn *from, 1218 const struct bpf_insn *aux, 1219 struct bpf_insn *to_buff, 1220 bool emit_zext) 1221 { 1222 struct bpf_insn *to = to_buff; 1223 u32 imm_rnd = get_random_u32(); 1224 s16 off; 1225 1226 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 1227 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 1228 1229 /* Constraints on AX register: 1230 * 1231 * AX register is inaccessible from user space. It is mapped in 1232 * all JITs, and used here for constant blinding rewrites. It is 1233 * typically "stateless" meaning its contents are only valid within 1234 * the executed instruction, but not across several instructions. 1235 * There are a few exceptions however which are further detailed 1236 * below. 1237 * 1238 * Constant blinding is only used by JITs, not in the interpreter. 1239 * The interpreter uses AX in some occasions as a local temporary 1240 * register e.g. in DIV or MOD instructions. 1241 * 1242 * In restricted circumstances, the verifier can also use the AX 1243 * register for rewrites as long as they do not interfere with 1244 * the above cases! 1245 */ 1246 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 1247 goto out; 1248 1249 if (from->imm == 0 && 1250 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 1251 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 1252 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 1253 goto out; 1254 } 1255 1256 switch (from->code) { 1257 case BPF_ALU | BPF_ADD | BPF_K: 1258 case BPF_ALU | BPF_SUB | BPF_K: 1259 case BPF_ALU | BPF_AND | BPF_K: 1260 case BPF_ALU | BPF_OR | BPF_K: 1261 case BPF_ALU | BPF_XOR | BPF_K: 1262 case BPF_ALU | BPF_MUL | BPF_K: 1263 case BPF_ALU | BPF_MOV | BPF_K: 1264 case BPF_ALU | BPF_DIV | BPF_K: 1265 case BPF_ALU | BPF_MOD | BPF_K: 1266 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1267 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1268 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 1269 break; 1270 1271 case BPF_ALU64 | BPF_ADD | BPF_K: 1272 case BPF_ALU64 | BPF_SUB | BPF_K: 1273 case BPF_ALU64 | BPF_AND | BPF_K: 1274 case BPF_ALU64 | BPF_OR | BPF_K: 1275 case BPF_ALU64 | BPF_XOR | BPF_K: 1276 case BPF_ALU64 | BPF_MUL | BPF_K: 1277 case BPF_ALU64 | BPF_MOV | BPF_K: 1278 case BPF_ALU64 | BPF_DIV | BPF_K: 1279 case BPF_ALU64 | BPF_MOD | BPF_K: 1280 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1281 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1282 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 1283 break; 1284 1285 case BPF_JMP | BPF_JEQ | BPF_K: 1286 case BPF_JMP | BPF_JNE | BPF_K: 1287 case BPF_JMP | BPF_JGT | BPF_K: 1288 case BPF_JMP | BPF_JLT | BPF_K: 1289 case BPF_JMP | BPF_JGE | BPF_K: 1290 case BPF_JMP | BPF_JLE | BPF_K: 1291 case BPF_JMP | BPF_JSGT | BPF_K: 1292 case BPF_JMP | BPF_JSLT | BPF_K: 1293 case BPF_JMP | BPF_JSGE | BPF_K: 1294 case BPF_JMP | BPF_JSLE | BPF_K: 1295 case BPF_JMP | BPF_JSET | BPF_K: 1296 /* Accommodate for extra offset in case of a backjump. */ 1297 off = from->off; 1298 if (off < 0) 1299 off -= 2; 1300 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1301 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1302 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1303 break; 1304 1305 case BPF_JMP32 | BPF_JEQ | BPF_K: 1306 case BPF_JMP32 | BPF_JNE | BPF_K: 1307 case BPF_JMP32 | BPF_JGT | BPF_K: 1308 case BPF_JMP32 | BPF_JLT | BPF_K: 1309 case BPF_JMP32 | BPF_JGE | BPF_K: 1310 case BPF_JMP32 | BPF_JLE | BPF_K: 1311 case BPF_JMP32 | BPF_JSGT | BPF_K: 1312 case BPF_JMP32 | BPF_JSLT | BPF_K: 1313 case BPF_JMP32 | BPF_JSGE | BPF_K: 1314 case BPF_JMP32 | BPF_JSLE | BPF_K: 1315 case BPF_JMP32 | BPF_JSET | BPF_K: 1316 /* Accommodate for extra offset in case of a backjump. */ 1317 off = from->off; 1318 if (off < 0) 1319 off -= 2; 1320 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1321 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1322 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1323 off); 1324 break; 1325 1326 case BPF_LD | BPF_IMM | BPF_DW: 1327 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1328 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1329 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1330 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1331 break; 1332 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1333 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1334 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1335 if (emit_zext) 1336 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1337 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1338 break; 1339 1340 case BPF_ST | BPF_MEM | BPF_DW: 1341 case BPF_ST | BPF_MEM | BPF_W: 1342 case BPF_ST | BPF_MEM | BPF_H: 1343 case BPF_ST | BPF_MEM | BPF_B: 1344 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1345 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1346 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1347 break; 1348 } 1349 out: 1350 return to - to_buff; 1351 } 1352 1353 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1354 gfp_t gfp_extra_flags) 1355 { 1356 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1357 struct bpf_prog *fp; 1358 1359 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1360 if (fp != NULL) { 1361 /* aux->prog still points to the fp_other one, so 1362 * when promoting the clone to the real program, 1363 * this still needs to be adapted. 1364 */ 1365 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1366 } 1367 1368 return fp; 1369 } 1370 1371 static void bpf_prog_clone_free(struct bpf_prog *fp) 1372 { 1373 /* aux was stolen by the other clone, so we cannot free 1374 * it from this path! It will be freed eventually by the 1375 * other program on release. 1376 * 1377 * At this point, we don't need a deferred release since 1378 * clone is guaranteed to not be locked. 1379 */ 1380 fp->aux = NULL; 1381 fp->stats = NULL; 1382 fp->active = NULL; 1383 __bpf_prog_free(fp); 1384 } 1385 1386 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1387 { 1388 /* We have to repoint aux->prog to self, as we don't 1389 * know whether fp here is the clone or the original. 1390 */ 1391 fp->aux->prog = fp; 1392 bpf_prog_clone_free(fp_other); 1393 } 1394 1395 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1396 { 1397 struct bpf_insn insn_buff[16], aux[2]; 1398 struct bpf_prog *clone, *tmp; 1399 int insn_delta, insn_cnt; 1400 struct bpf_insn *insn; 1401 int i, rewritten; 1402 1403 if (!prog->blinding_requested || prog->blinded) 1404 return prog; 1405 1406 clone = bpf_prog_clone_create(prog, GFP_USER); 1407 if (!clone) 1408 return ERR_PTR(-ENOMEM); 1409 1410 insn_cnt = clone->len; 1411 insn = clone->insnsi; 1412 1413 for (i = 0; i < insn_cnt; i++, insn++) { 1414 if (bpf_pseudo_func(insn)) { 1415 /* ld_imm64 with an address of bpf subprog is not 1416 * a user controlled constant. Don't randomize it, 1417 * since it will conflict with jit_subprogs() logic. 1418 */ 1419 insn++; 1420 i++; 1421 continue; 1422 } 1423 1424 /* We temporarily need to hold the original ld64 insn 1425 * so that we can still access the first part in the 1426 * second blinding run. 1427 */ 1428 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1429 insn[1].code == 0) 1430 memcpy(aux, insn, sizeof(aux)); 1431 1432 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1433 clone->aux->verifier_zext); 1434 if (!rewritten) 1435 continue; 1436 1437 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1438 if (IS_ERR(tmp)) { 1439 /* Patching may have repointed aux->prog during 1440 * realloc from the original one, so we need to 1441 * fix it up here on error. 1442 */ 1443 bpf_jit_prog_release_other(prog, clone); 1444 return tmp; 1445 } 1446 1447 clone = tmp; 1448 insn_delta = rewritten - 1; 1449 1450 /* Walk new program and skip insns we just inserted. */ 1451 insn = clone->insnsi + i + insn_delta; 1452 insn_cnt += insn_delta; 1453 i += insn_delta; 1454 } 1455 1456 clone->blinded = 1; 1457 return clone; 1458 } 1459 #endif /* CONFIG_BPF_JIT */ 1460 1461 /* Base function for offset calculation. Needs to go into .text section, 1462 * therefore keeping it non-static as well; will also be used by JITs 1463 * anyway later on, so do not let the compiler omit it. This also needs 1464 * to go into kallsyms for correlation from e.g. bpftool, so naming 1465 * must not change. 1466 */ 1467 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1468 { 1469 return 0; 1470 } 1471 EXPORT_SYMBOL_GPL(__bpf_call_base); 1472 1473 /* All UAPI available opcodes. */ 1474 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1475 /* 32 bit ALU operations. */ \ 1476 /* Register based. */ \ 1477 INSN_3(ALU, ADD, X), \ 1478 INSN_3(ALU, SUB, X), \ 1479 INSN_3(ALU, AND, X), \ 1480 INSN_3(ALU, OR, X), \ 1481 INSN_3(ALU, LSH, X), \ 1482 INSN_3(ALU, RSH, X), \ 1483 INSN_3(ALU, XOR, X), \ 1484 INSN_3(ALU, MUL, X), \ 1485 INSN_3(ALU, MOV, X), \ 1486 INSN_3(ALU, ARSH, X), \ 1487 INSN_3(ALU, DIV, X), \ 1488 INSN_3(ALU, MOD, X), \ 1489 INSN_2(ALU, NEG), \ 1490 INSN_3(ALU, END, TO_BE), \ 1491 INSN_3(ALU, END, TO_LE), \ 1492 /* Immediate based. */ \ 1493 INSN_3(ALU, ADD, K), \ 1494 INSN_3(ALU, SUB, K), \ 1495 INSN_3(ALU, AND, K), \ 1496 INSN_3(ALU, OR, K), \ 1497 INSN_3(ALU, LSH, K), \ 1498 INSN_3(ALU, RSH, K), \ 1499 INSN_3(ALU, XOR, K), \ 1500 INSN_3(ALU, MUL, K), \ 1501 INSN_3(ALU, MOV, K), \ 1502 INSN_3(ALU, ARSH, K), \ 1503 INSN_3(ALU, DIV, K), \ 1504 INSN_3(ALU, MOD, K), \ 1505 /* 64 bit ALU operations. */ \ 1506 /* Register based. */ \ 1507 INSN_3(ALU64, ADD, X), \ 1508 INSN_3(ALU64, SUB, X), \ 1509 INSN_3(ALU64, AND, X), \ 1510 INSN_3(ALU64, OR, X), \ 1511 INSN_3(ALU64, LSH, X), \ 1512 INSN_3(ALU64, RSH, X), \ 1513 INSN_3(ALU64, XOR, X), \ 1514 INSN_3(ALU64, MUL, X), \ 1515 INSN_3(ALU64, MOV, X), \ 1516 INSN_3(ALU64, ARSH, X), \ 1517 INSN_3(ALU64, DIV, X), \ 1518 INSN_3(ALU64, MOD, X), \ 1519 INSN_2(ALU64, NEG), \ 1520 /* Immediate based. */ \ 1521 INSN_3(ALU64, ADD, K), \ 1522 INSN_3(ALU64, SUB, K), \ 1523 INSN_3(ALU64, AND, K), \ 1524 INSN_3(ALU64, OR, K), \ 1525 INSN_3(ALU64, LSH, K), \ 1526 INSN_3(ALU64, RSH, K), \ 1527 INSN_3(ALU64, XOR, K), \ 1528 INSN_3(ALU64, MUL, K), \ 1529 INSN_3(ALU64, MOV, K), \ 1530 INSN_3(ALU64, ARSH, K), \ 1531 INSN_3(ALU64, DIV, K), \ 1532 INSN_3(ALU64, MOD, K), \ 1533 /* Call instruction. */ \ 1534 INSN_2(JMP, CALL), \ 1535 /* Exit instruction. */ \ 1536 INSN_2(JMP, EXIT), \ 1537 /* 32-bit Jump instructions. */ \ 1538 /* Register based. */ \ 1539 INSN_3(JMP32, JEQ, X), \ 1540 INSN_3(JMP32, JNE, X), \ 1541 INSN_3(JMP32, JGT, X), \ 1542 INSN_3(JMP32, JLT, X), \ 1543 INSN_3(JMP32, JGE, X), \ 1544 INSN_3(JMP32, JLE, X), \ 1545 INSN_3(JMP32, JSGT, X), \ 1546 INSN_3(JMP32, JSLT, X), \ 1547 INSN_3(JMP32, JSGE, X), \ 1548 INSN_3(JMP32, JSLE, X), \ 1549 INSN_3(JMP32, JSET, X), \ 1550 /* Immediate based. */ \ 1551 INSN_3(JMP32, JEQ, K), \ 1552 INSN_3(JMP32, JNE, K), \ 1553 INSN_3(JMP32, JGT, K), \ 1554 INSN_3(JMP32, JLT, K), \ 1555 INSN_3(JMP32, JGE, K), \ 1556 INSN_3(JMP32, JLE, K), \ 1557 INSN_3(JMP32, JSGT, K), \ 1558 INSN_3(JMP32, JSLT, K), \ 1559 INSN_3(JMP32, JSGE, K), \ 1560 INSN_3(JMP32, JSLE, K), \ 1561 INSN_3(JMP32, JSET, K), \ 1562 /* Jump instructions. */ \ 1563 /* Register based. */ \ 1564 INSN_3(JMP, JEQ, X), \ 1565 INSN_3(JMP, JNE, X), \ 1566 INSN_3(JMP, JGT, X), \ 1567 INSN_3(JMP, JLT, X), \ 1568 INSN_3(JMP, JGE, X), \ 1569 INSN_3(JMP, JLE, X), \ 1570 INSN_3(JMP, JSGT, X), \ 1571 INSN_3(JMP, JSLT, X), \ 1572 INSN_3(JMP, JSGE, X), \ 1573 INSN_3(JMP, JSLE, X), \ 1574 INSN_3(JMP, JSET, X), \ 1575 /* Immediate based. */ \ 1576 INSN_3(JMP, JEQ, K), \ 1577 INSN_3(JMP, JNE, K), \ 1578 INSN_3(JMP, JGT, K), \ 1579 INSN_3(JMP, JLT, K), \ 1580 INSN_3(JMP, JGE, K), \ 1581 INSN_3(JMP, JLE, K), \ 1582 INSN_3(JMP, JSGT, K), \ 1583 INSN_3(JMP, JSLT, K), \ 1584 INSN_3(JMP, JSGE, K), \ 1585 INSN_3(JMP, JSLE, K), \ 1586 INSN_3(JMP, JSET, K), \ 1587 INSN_2(JMP, JA), \ 1588 /* Store instructions. */ \ 1589 /* Register based. */ \ 1590 INSN_3(STX, MEM, B), \ 1591 INSN_3(STX, MEM, H), \ 1592 INSN_3(STX, MEM, W), \ 1593 INSN_3(STX, MEM, DW), \ 1594 INSN_3(STX, ATOMIC, W), \ 1595 INSN_3(STX, ATOMIC, DW), \ 1596 /* Immediate based. */ \ 1597 INSN_3(ST, MEM, B), \ 1598 INSN_3(ST, MEM, H), \ 1599 INSN_3(ST, MEM, W), \ 1600 INSN_3(ST, MEM, DW), \ 1601 /* Load instructions. */ \ 1602 /* Register based. */ \ 1603 INSN_3(LDX, MEM, B), \ 1604 INSN_3(LDX, MEM, H), \ 1605 INSN_3(LDX, MEM, W), \ 1606 INSN_3(LDX, MEM, DW), \ 1607 /* Immediate based. */ \ 1608 INSN_3(LD, IMM, DW) 1609 1610 bool bpf_opcode_in_insntable(u8 code) 1611 { 1612 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1613 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1614 static const bool public_insntable[256] = { 1615 [0 ... 255] = false, 1616 /* Now overwrite non-defaults ... */ 1617 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1618 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1619 [BPF_LD | BPF_ABS | BPF_B] = true, 1620 [BPF_LD | BPF_ABS | BPF_H] = true, 1621 [BPF_LD | BPF_ABS | BPF_W] = true, 1622 [BPF_LD | BPF_IND | BPF_B] = true, 1623 [BPF_LD | BPF_IND | BPF_H] = true, 1624 [BPF_LD | BPF_IND | BPF_W] = true, 1625 }; 1626 #undef BPF_INSN_3_TBL 1627 #undef BPF_INSN_2_TBL 1628 return public_insntable[code]; 1629 } 1630 1631 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1632 u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) 1633 { 1634 memset(dst, 0, size); 1635 return -EFAULT; 1636 } 1637 1638 /** 1639 * ___bpf_prog_run - run eBPF program on a given context 1640 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1641 * @insn: is the array of eBPF instructions 1642 * 1643 * Decode and execute eBPF instructions. 1644 * 1645 * Return: whatever value is in %BPF_R0 at program exit 1646 */ 1647 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) 1648 { 1649 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1650 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1651 static const void * const jumptable[256] __annotate_jump_table = { 1652 [0 ... 255] = &&default_label, 1653 /* Now overwrite non-defaults ... */ 1654 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1655 /* Non-UAPI available opcodes. */ 1656 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1657 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1658 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC, 1659 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1660 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1661 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1662 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1663 }; 1664 #undef BPF_INSN_3_LBL 1665 #undef BPF_INSN_2_LBL 1666 u32 tail_call_cnt = 0; 1667 1668 #define CONT ({ insn++; goto select_insn; }) 1669 #define CONT_JMP ({ insn++; goto select_insn; }) 1670 1671 select_insn: 1672 goto *jumptable[insn->code]; 1673 1674 /* Explicitly mask the register-based shift amounts with 63 or 31 1675 * to avoid undefined behavior. Normally this won't affect the 1676 * generated code, for example, in case of native 64 bit archs such 1677 * as x86-64 or arm64, the compiler is optimizing the AND away for 1678 * the interpreter. In case of JITs, each of the JIT backends compiles 1679 * the BPF shift operations to machine instructions which produce 1680 * implementation-defined results in such a case; the resulting 1681 * contents of the register may be arbitrary, but program behaviour 1682 * as a whole remains defined. In other words, in case of JIT backends, 1683 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation. 1684 */ 1685 /* ALU (shifts) */ 1686 #define SHT(OPCODE, OP) \ 1687 ALU64_##OPCODE##_X: \ 1688 DST = DST OP (SRC & 63); \ 1689 CONT; \ 1690 ALU_##OPCODE##_X: \ 1691 DST = (u32) DST OP ((u32) SRC & 31); \ 1692 CONT; \ 1693 ALU64_##OPCODE##_K: \ 1694 DST = DST OP IMM; \ 1695 CONT; \ 1696 ALU_##OPCODE##_K: \ 1697 DST = (u32) DST OP (u32) IMM; \ 1698 CONT; 1699 /* ALU (rest) */ 1700 #define ALU(OPCODE, OP) \ 1701 ALU64_##OPCODE##_X: \ 1702 DST = DST OP SRC; \ 1703 CONT; \ 1704 ALU_##OPCODE##_X: \ 1705 DST = (u32) DST OP (u32) SRC; \ 1706 CONT; \ 1707 ALU64_##OPCODE##_K: \ 1708 DST = DST OP IMM; \ 1709 CONT; \ 1710 ALU_##OPCODE##_K: \ 1711 DST = (u32) DST OP (u32) IMM; \ 1712 CONT; 1713 ALU(ADD, +) 1714 ALU(SUB, -) 1715 ALU(AND, &) 1716 ALU(OR, |) 1717 ALU(XOR, ^) 1718 ALU(MUL, *) 1719 SHT(LSH, <<) 1720 SHT(RSH, >>) 1721 #undef SHT 1722 #undef ALU 1723 ALU_NEG: 1724 DST = (u32) -DST; 1725 CONT; 1726 ALU64_NEG: 1727 DST = -DST; 1728 CONT; 1729 ALU_MOV_X: 1730 DST = (u32) SRC; 1731 CONT; 1732 ALU_MOV_K: 1733 DST = (u32) IMM; 1734 CONT; 1735 ALU64_MOV_X: 1736 DST = SRC; 1737 CONT; 1738 ALU64_MOV_K: 1739 DST = IMM; 1740 CONT; 1741 LD_IMM_DW: 1742 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1743 insn++; 1744 CONT; 1745 ALU_ARSH_X: 1746 DST = (u64) (u32) (((s32) DST) >> (SRC & 31)); 1747 CONT; 1748 ALU_ARSH_K: 1749 DST = (u64) (u32) (((s32) DST) >> IMM); 1750 CONT; 1751 ALU64_ARSH_X: 1752 (*(s64 *) &DST) >>= (SRC & 63); 1753 CONT; 1754 ALU64_ARSH_K: 1755 (*(s64 *) &DST) >>= IMM; 1756 CONT; 1757 ALU64_MOD_X: 1758 div64_u64_rem(DST, SRC, &AX); 1759 DST = AX; 1760 CONT; 1761 ALU_MOD_X: 1762 AX = (u32) DST; 1763 DST = do_div(AX, (u32) SRC); 1764 CONT; 1765 ALU64_MOD_K: 1766 div64_u64_rem(DST, IMM, &AX); 1767 DST = AX; 1768 CONT; 1769 ALU_MOD_K: 1770 AX = (u32) DST; 1771 DST = do_div(AX, (u32) IMM); 1772 CONT; 1773 ALU64_DIV_X: 1774 DST = div64_u64(DST, SRC); 1775 CONT; 1776 ALU_DIV_X: 1777 AX = (u32) DST; 1778 do_div(AX, (u32) SRC); 1779 DST = (u32) AX; 1780 CONT; 1781 ALU64_DIV_K: 1782 DST = div64_u64(DST, IMM); 1783 CONT; 1784 ALU_DIV_K: 1785 AX = (u32) DST; 1786 do_div(AX, (u32) IMM); 1787 DST = (u32) AX; 1788 CONT; 1789 ALU_END_TO_BE: 1790 switch (IMM) { 1791 case 16: 1792 DST = (__force u16) cpu_to_be16(DST); 1793 break; 1794 case 32: 1795 DST = (__force u32) cpu_to_be32(DST); 1796 break; 1797 case 64: 1798 DST = (__force u64) cpu_to_be64(DST); 1799 break; 1800 } 1801 CONT; 1802 ALU_END_TO_LE: 1803 switch (IMM) { 1804 case 16: 1805 DST = (__force u16) cpu_to_le16(DST); 1806 break; 1807 case 32: 1808 DST = (__force u32) cpu_to_le32(DST); 1809 break; 1810 case 64: 1811 DST = (__force u64) cpu_to_le64(DST); 1812 break; 1813 } 1814 CONT; 1815 1816 /* CALL */ 1817 JMP_CALL: 1818 /* Function call scratches BPF_R1-BPF_R5 registers, 1819 * preserves BPF_R6-BPF_R9, and stores return value 1820 * into BPF_R0. 1821 */ 1822 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1823 BPF_R4, BPF_R5); 1824 CONT; 1825 1826 JMP_CALL_ARGS: 1827 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 1828 BPF_R3, BPF_R4, 1829 BPF_R5, 1830 insn + insn->off + 1); 1831 CONT; 1832 1833 JMP_TAIL_CALL: { 1834 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1835 struct bpf_array *array = container_of(map, struct bpf_array, map); 1836 struct bpf_prog *prog; 1837 u32 index = BPF_R3; 1838 1839 if (unlikely(index >= array->map.max_entries)) 1840 goto out; 1841 1842 if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT)) 1843 goto out; 1844 1845 tail_call_cnt++; 1846 1847 prog = READ_ONCE(array->ptrs[index]); 1848 if (!prog) 1849 goto out; 1850 1851 /* ARG1 at this point is guaranteed to point to CTX from 1852 * the verifier side due to the fact that the tail call is 1853 * handled like a helper, that is, bpf_tail_call_proto, 1854 * where arg1_type is ARG_PTR_TO_CTX. 1855 */ 1856 insn = prog->insnsi; 1857 goto select_insn; 1858 out: 1859 CONT; 1860 } 1861 JMP_JA: 1862 insn += insn->off; 1863 CONT; 1864 JMP_EXIT: 1865 return BPF_R0; 1866 /* JMP */ 1867 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 1868 JMP_##OPCODE##_X: \ 1869 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 1870 insn += insn->off; \ 1871 CONT_JMP; \ 1872 } \ 1873 CONT; \ 1874 JMP32_##OPCODE##_X: \ 1875 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 1876 insn += insn->off; \ 1877 CONT_JMP; \ 1878 } \ 1879 CONT; \ 1880 JMP_##OPCODE##_K: \ 1881 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 1882 insn += insn->off; \ 1883 CONT_JMP; \ 1884 } \ 1885 CONT; \ 1886 JMP32_##OPCODE##_K: \ 1887 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 1888 insn += insn->off; \ 1889 CONT_JMP; \ 1890 } \ 1891 CONT; 1892 COND_JMP(u, JEQ, ==) 1893 COND_JMP(u, JNE, !=) 1894 COND_JMP(u, JGT, >) 1895 COND_JMP(u, JLT, <) 1896 COND_JMP(u, JGE, >=) 1897 COND_JMP(u, JLE, <=) 1898 COND_JMP(u, JSET, &) 1899 COND_JMP(s, JSGT, >) 1900 COND_JMP(s, JSLT, <) 1901 COND_JMP(s, JSGE, >=) 1902 COND_JMP(s, JSLE, <=) 1903 #undef COND_JMP 1904 /* ST, STX and LDX*/ 1905 ST_NOSPEC: 1906 /* Speculation barrier for mitigating Speculative Store Bypass. 1907 * In case of arm64, we rely on the firmware mitigation as 1908 * controlled via the ssbd kernel parameter. Whenever the 1909 * mitigation is enabled, it works for all of the kernel code 1910 * with no need to provide any additional instructions here. 1911 * In case of x86, we use 'lfence' insn for mitigation. We 1912 * reuse preexisting logic from Spectre v1 mitigation that 1913 * happens to produce the required code on x86 for v4 as well. 1914 */ 1915 #ifdef CONFIG_X86 1916 barrier_nospec(); 1917 #endif 1918 CONT; 1919 #define LDST(SIZEOP, SIZE) \ 1920 STX_MEM_##SIZEOP: \ 1921 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 1922 CONT; \ 1923 ST_MEM_##SIZEOP: \ 1924 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 1925 CONT; \ 1926 LDX_MEM_##SIZEOP: \ 1927 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 1928 CONT; \ 1929 LDX_PROBE_MEM_##SIZEOP: \ 1930 bpf_probe_read_kernel(&DST, sizeof(SIZE), \ 1931 (const void *)(long) (SRC + insn->off)); \ 1932 DST = *((SIZE *)&DST); \ 1933 CONT; 1934 1935 LDST(B, u8) 1936 LDST(H, u16) 1937 LDST(W, u32) 1938 LDST(DW, u64) 1939 #undef LDST 1940 1941 #define ATOMIC_ALU_OP(BOP, KOP) \ 1942 case BOP: \ 1943 if (BPF_SIZE(insn->code) == BPF_W) \ 1944 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \ 1945 (DST + insn->off)); \ 1946 else \ 1947 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \ 1948 (DST + insn->off)); \ 1949 break; \ 1950 case BOP | BPF_FETCH: \ 1951 if (BPF_SIZE(insn->code) == BPF_W) \ 1952 SRC = (u32) atomic_fetch_##KOP( \ 1953 (u32) SRC, \ 1954 (atomic_t *)(unsigned long) (DST + insn->off)); \ 1955 else \ 1956 SRC = (u64) atomic64_fetch_##KOP( \ 1957 (u64) SRC, \ 1958 (atomic64_t *)(unsigned long) (DST + insn->off)); \ 1959 break; 1960 1961 STX_ATOMIC_DW: 1962 STX_ATOMIC_W: 1963 switch (IMM) { 1964 ATOMIC_ALU_OP(BPF_ADD, add) 1965 ATOMIC_ALU_OP(BPF_AND, and) 1966 ATOMIC_ALU_OP(BPF_OR, or) 1967 ATOMIC_ALU_OP(BPF_XOR, xor) 1968 #undef ATOMIC_ALU_OP 1969 1970 case BPF_XCHG: 1971 if (BPF_SIZE(insn->code) == BPF_W) 1972 SRC = (u32) atomic_xchg( 1973 (atomic_t *)(unsigned long) (DST + insn->off), 1974 (u32) SRC); 1975 else 1976 SRC = (u64) atomic64_xchg( 1977 (atomic64_t *)(unsigned long) (DST + insn->off), 1978 (u64) SRC); 1979 break; 1980 case BPF_CMPXCHG: 1981 if (BPF_SIZE(insn->code) == BPF_W) 1982 BPF_R0 = (u32) atomic_cmpxchg( 1983 (atomic_t *)(unsigned long) (DST + insn->off), 1984 (u32) BPF_R0, (u32) SRC); 1985 else 1986 BPF_R0 = (u64) atomic64_cmpxchg( 1987 (atomic64_t *)(unsigned long) (DST + insn->off), 1988 (u64) BPF_R0, (u64) SRC); 1989 break; 1990 1991 default: 1992 goto default_label; 1993 } 1994 CONT; 1995 1996 default_label: 1997 /* If we ever reach this, we have a bug somewhere. Die hard here 1998 * instead of just returning 0; we could be somewhere in a subprog, 1999 * so execution could continue otherwise which we do /not/ want. 2000 * 2001 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 2002 */ 2003 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n", 2004 insn->code, insn->imm); 2005 BUG_ON(1); 2006 return 0; 2007 } 2008 2009 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 2010 #define DEFINE_BPF_PROG_RUN(stack_size) \ 2011 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 2012 { \ 2013 u64 stack[stack_size / sizeof(u64)]; \ 2014 u64 regs[MAX_BPF_EXT_REG] = {}; \ 2015 \ 2016 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2017 ARG1 = (u64) (unsigned long) ctx; \ 2018 return ___bpf_prog_run(regs, insn); \ 2019 } 2020 2021 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 2022 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 2023 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 2024 const struct bpf_insn *insn) \ 2025 { \ 2026 u64 stack[stack_size / sizeof(u64)]; \ 2027 u64 regs[MAX_BPF_EXT_REG]; \ 2028 \ 2029 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2030 BPF_R1 = r1; \ 2031 BPF_R2 = r2; \ 2032 BPF_R3 = r3; \ 2033 BPF_R4 = r4; \ 2034 BPF_R5 = r5; \ 2035 return ___bpf_prog_run(regs, insn); \ 2036 } 2037 2038 #define EVAL1(FN, X) FN(X) 2039 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 2040 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 2041 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 2042 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 2043 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 2044 2045 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 2046 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 2047 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 2048 2049 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 2050 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 2051 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 2052 2053 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 2054 2055 static unsigned int (*interpreters[])(const void *ctx, 2056 const struct bpf_insn *insn) = { 2057 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2058 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2059 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2060 }; 2061 #undef PROG_NAME_LIST 2062 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 2063 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 2064 const struct bpf_insn *insn) = { 2065 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2066 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2067 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2068 }; 2069 #undef PROG_NAME_LIST 2070 2071 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 2072 { 2073 stack_depth = max_t(u32, stack_depth, 1); 2074 insn->off = (s16) insn->imm; 2075 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 2076 __bpf_call_base_args; 2077 insn->code = BPF_JMP | BPF_CALL_ARGS; 2078 } 2079 2080 #else 2081 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 2082 const struct bpf_insn *insn) 2083 { 2084 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 2085 * is not working properly, so warn about it! 2086 */ 2087 WARN_ON_ONCE(1); 2088 return 0; 2089 } 2090 #endif 2091 2092 bool bpf_prog_map_compatible(struct bpf_map *map, 2093 const struct bpf_prog *fp) 2094 { 2095 bool ret; 2096 2097 if (fp->kprobe_override) 2098 return false; 2099 2100 spin_lock(&map->owner.lock); 2101 if (!map->owner.type) { 2102 /* There's no owner yet where we could check for 2103 * compatibility. 2104 */ 2105 map->owner.type = fp->type; 2106 map->owner.jited = fp->jited; 2107 map->owner.xdp_has_frags = fp->aux->xdp_has_frags; 2108 ret = true; 2109 } else { 2110 ret = map->owner.type == fp->type && 2111 map->owner.jited == fp->jited && 2112 map->owner.xdp_has_frags == fp->aux->xdp_has_frags; 2113 } 2114 spin_unlock(&map->owner.lock); 2115 2116 return ret; 2117 } 2118 2119 static int bpf_check_tail_call(const struct bpf_prog *fp) 2120 { 2121 struct bpf_prog_aux *aux = fp->aux; 2122 int i, ret = 0; 2123 2124 mutex_lock(&aux->used_maps_mutex); 2125 for (i = 0; i < aux->used_map_cnt; i++) { 2126 struct bpf_map *map = aux->used_maps[i]; 2127 2128 if (!map_type_contains_progs(map)) 2129 continue; 2130 2131 if (!bpf_prog_map_compatible(map, fp)) { 2132 ret = -EINVAL; 2133 goto out; 2134 } 2135 } 2136 2137 out: 2138 mutex_unlock(&aux->used_maps_mutex); 2139 return ret; 2140 } 2141 2142 static void bpf_prog_select_func(struct bpf_prog *fp) 2143 { 2144 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 2145 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 2146 2147 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 2148 #else 2149 fp->bpf_func = __bpf_prog_ret0_warn; 2150 #endif 2151 } 2152 2153 /** 2154 * bpf_prog_select_runtime - select exec runtime for BPF program 2155 * @fp: bpf_prog populated with BPF program 2156 * @err: pointer to error variable 2157 * 2158 * Try to JIT eBPF program, if JIT is not available, use interpreter. 2159 * The BPF program will be executed via bpf_prog_run() function. 2160 * 2161 * Return: the &fp argument along with &err set to 0 for success or 2162 * a negative errno code on failure 2163 */ 2164 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 2165 { 2166 /* In case of BPF to BPF calls, verifier did all the prep 2167 * work with regards to JITing, etc. 2168 */ 2169 bool jit_needed = false; 2170 2171 if (fp->bpf_func) 2172 goto finalize; 2173 2174 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || 2175 bpf_prog_has_kfunc_call(fp)) 2176 jit_needed = true; 2177 2178 bpf_prog_select_func(fp); 2179 2180 /* eBPF JITs can rewrite the program in case constant 2181 * blinding is active. However, in case of error during 2182 * blinding, bpf_int_jit_compile() must always return a 2183 * valid program, which in this case would simply not 2184 * be JITed, but falls back to the interpreter. 2185 */ 2186 if (!bpf_prog_is_dev_bound(fp->aux)) { 2187 *err = bpf_prog_alloc_jited_linfo(fp); 2188 if (*err) 2189 return fp; 2190 2191 fp = bpf_int_jit_compile(fp); 2192 bpf_prog_jit_attempt_done(fp); 2193 if (!fp->jited && jit_needed) { 2194 *err = -ENOTSUPP; 2195 return fp; 2196 } 2197 } else { 2198 *err = bpf_prog_offload_compile(fp); 2199 if (*err) 2200 return fp; 2201 } 2202 2203 finalize: 2204 bpf_prog_lock_ro(fp); 2205 2206 /* The tail call compatibility check can only be done at 2207 * this late stage as we need to determine, if we deal 2208 * with JITed or non JITed program concatenations and not 2209 * all eBPF JITs might immediately support all features. 2210 */ 2211 *err = bpf_check_tail_call(fp); 2212 2213 return fp; 2214 } 2215 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 2216 2217 static unsigned int __bpf_prog_ret1(const void *ctx, 2218 const struct bpf_insn *insn) 2219 { 2220 return 1; 2221 } 2222 2223 static struct bpf_prog_dummy { 2224 struct bpf_prog prog; 2225 } dummy_bpf_prog = { 2226 .prog = { 2227 .bpf_func = __bpf_prog_ret1, 2228 }, 2229 }; 2230 2231 struct bpf_empty_prog_array bpf_empty_prog_array = { 2232 .null_prog = NULL, 2233 }; 2234 EXPORT_SYMBOL(bpf_empty_prog_array); 2235 2236 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 2237 { 2238 if (prog_cnt) 2239 return kzalloc(sizeof(struct bpf_prog_array) + 2240 sizeof(struct bpf_prog_array_item) * 2241 (prog_cnt + 1), 2242 flags); 2243 2244 return &bpf_empty_prog_array.hdr; 2245 } 2246 2247 void bpf_prog_array_free(struct bpf_prog_array *progs) 2248 { 2249 if (!progs || progs == &bpf_empty_prog_array.hdr) 2250 return; 2251 kfree_rcu(progs, rcu); 2252 } 2253 2254 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu) 2255 { 2256 struct bpf_prog_array *progs; 2257 2258 /* If RCU Tasks Trace grace period implies RCU grace period, there is 2259 * no need to call kfree_rcu(), just call kfree() directly. 2260 */ 2261 progs = container_of(rcu, struct bpf_prog_array, rcu); 2262 if (rcu_trace_implies_rcu_gp()) 2263 kfree(progs); 2264 else 2265 kfree_rcu(progs, rcu); 2266 } 2267 2268 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs) 2269 { 2270 if (!progs || progs == &bpf_empty_prog_array.hdr) 2271 return; 2272 call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb); 2273 } 2274 2275 int bpf_prog_array_length(struct bpf_prog_array *array) 2276 { 2277 struct bpf_prog_array_item *item; 2278 u32 cnt = 0; 2279 2280 for (item = array->items; item->prog; item++) 2281 if (item->prog != &dummy_bpf_prog.prog) 2282 cnt++; 2283 return cnt; 2284 } 2285 2286 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 2287 { 2288 struct bpf_prog_array_item *item; 2289 2290 for (item = array->items; item->prog; item++) 2291 if (item->prog != &dummy_bpf_prog.prog) 2292 return false; 2293 return true; 2294 } 2295 2296 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 2297 u32 *prog_ids, 2298 u32 request_cnt) 2299 { 2300 struct bpf_prog_array_item *item; 2301 int i = 0; 2302 2303 for (item = array->items; item->prog; item++) { 2304 if (item->prog == &dummy_bpf_prog.prog) 2305 continue; 2306 prog_ids[i] = item->prog->aux->id; 2307 if (++i == request_cnt) { 2308 item++; 2309 break; 2310 } 2311 } 2312 2313 return !!(item->prog); 2314 } 2315 2316 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 2317 __u32 __user *prog_ids, u32 cnt) 2318 { 2319 unsigned long err = 0; 2320 bool nospc; 2321 u32 *ids; 2322 2323 /* users of this function are doing: 2324 * cnt = bpf_prog_array_length(); 2325 * if (cnt > 0) 2326 * bpf_prog_array_copy_to_user(..., cnt); 2327 * so below kcalloc doesn't need extra cnt > 0 check. 2328 */ 2329 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 2330 if (!ids) 2331 return -ENOMEM; 2332 nospc = bpf_prog_array_copy_core(array, ids, cnt); 2333 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 2334 kfree(ids); 2335 if (err) 2336 return -EFAULT; 2337 if (nospc) 2338 return -ENOSPC; 2339 return 0; 2340 } 2341 2342 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 2343 struct bpf_prog *old_prog) 2344 { 2345 struct bpf_prog_array_item *item; 2346 2347 for (item = array->items; item->prog; item++) 2348 if (item->prog == old_prog) { 2349 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 2350 break; 2351 } 2352 } 2353 2354 /** 2355 * bpf_prog_array_delete_safe_at() - Replaces the program at the given 2356 * index into the program array with 2357 * a dummy no-op program. 2358 * @array: a bpf_prog_array 2359 * @index: the index of the program to replace 2360 * 2361 * Skips over dummy programs, by not counting them, when calculating 2362 * the position of the program to replace. 2363 * 2364 * Return: 2365 * * 0 - Success 2366 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2367 * * -ENOENT - Index out of range 2368 */ 2369 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) 2370 { 2371 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); 2372 } 2373 2374 /** 2375 * bpf_prog_array_update_at() - Updates the program at the given index 2376 * into the program array. 2377 * @array: a bpf_prog_array 2378 * @index: the index of the program to update 2379 * @prog: the program to insert into the array 2380 * 2381 * Skips over dummy programs, by not counting them, when calculating 2382 * the position of the program to update. 2383 * 2384 * Return: 2385 * * 0 - Success 2386 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2387 * * -ENOENT - Index out of range 2388 */ 2389 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, 2390 struct bpf_prog *prog) 2391 { 2392 struct bpf_prog_array_item *item; 2393 2394 if (unlikely(index < 0)) 2395 return -EINVAL; 2396 2397 for (item = array->items; item->prog; item++) { 2398 if (item->prog == &dummy_bpf_prog.prog) 2399 continue; 2400 if (!index) { 2401 WRITE_ONCE(item->prog, prog); 2402 return 0; 2403 } 2404 index--; 2405 } 2406 return -ENOENT; 2407 } 2408 2409 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 2410 struct bpf_prog *exclude_prog, 2411 struct bpf_prog *include_prog, 2412 u64 bpf_cookie, 2413 struct bpf_prog_array **new_array) 2414 { 2415 int new_prog_cnt, carry_prog_cnt = 0; 2416 struct bpf_prog_array_item *existing, *new; 2417 struct bpf_prog_array *array; 2418 bool found_exclude = false; 2419 2420 /* Figure out how many existing progs we need to carry over to 2421 * the new array. 2422 */ 2423 if (old_array) { 2424 existing = old_array->items; 2425 for (; existing->prog; existing++) { 2426 if (existing->prog == exclude_prog) { 2427 found_exclude = true; 2428 continue; 2429 } 2430 if (existing->prog != &dummy_bpf_prog.prog) 2431 carry_prog_cnt++; 2432 if (existing->prog == include_prog) 2433 return -EEXIST; 2434 } 2435 } 2436 2437 if (exclude_prog && !found_exclude) 2438 return -ENOENT; 2439 2440 /* How many progs (not NULL) will be in the new array? */ 2441 new_prog_cnt = carry_prog_cnt; 2442 if (include_prog) 2443 new_prog_cnt += 1; 2444 2445 /* Do we have any prog (not NULL) in the new array? */ 2446 if (!new_prog_cnt) { 2447 *new_array = NULL; 2448 return 0; 2449 } 2450 2451 /* +1 as the end of prog_array is marked with NULL */ 2452 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2453 if (!array) 2454 return -ENOMEM; 2455 new = array->items; 2456 2457 /* Fill in the new prog array */ 2458 if (carry_prog_cnt) { 2459 existing = old_array->items; 2460 for (; existing->prog; existing++) { 2461 if (existing->prog == exclude_prog || 2462 existing->prog == &dummy_bpf_prog.prog) 2463 continue; 2464 2465 new->prog = existing->prog; 2466 new->bpf_cookie = existing->bpf_cookie; 2467 new++; 2468 } 2469 } 2470 if (include_prog) { 2471 new->prog = include_prog; 2472 new->bpf_cookie = bpf_cookie; 2473 new++; 2474 } 2475 new->prog = NULL; 2476 *new_array = array; 2477 return 0; 2478 } 2479 2480 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2481 u32 *prog_ids, u32 request_cnt, 2482 u32 *prog_cnt) 2483 { 2484 u32 cnt = 0; 2485 2486 if (array) 2487 cnt = bpf_prog_array_length(array); 2488 2489 *prog_cnt = cnt; 2490 2491 /* return early if user requested only program count or nothing to copy */ 2492 if (!request_cnt || !cnt) 2493 return 0; 2494 2495 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2496 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2497 : 0; 2498 } 2499 2500 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2501 struct bpf_map **used_maps, u32 len) 2502 { 2503 struct bpf_map *map; 2504 u32 i; 2505 2506 for (i = 0; i < len; i++) { 2507 map = used_maps[i]; 2508 if (map->ops->map_poke_untrack) 2509 map->ops->map_poke_untrack(map, aux); 2510 bpf_map_put(map); 2511 } 2512 } 2513 2514 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2515 { 2516 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2517 kfree(aux->used_maps); 2518 } 2519 2520 void __bpf_free_used_btfs(struct bpf_prog_aux *aux, 2521 struct btf_mod_pair *used_btfs, u32 len) 2522 { 2523 #ifdef CONFIG_BPF_SYSCALL 2524 struct btf_mod_pair *btf_mod; 2525 u32 i; 2526 2527 for (i = 0; i < len; i++) { 2528 btf_mod = &used_btfs[i]; 2529 if (btf_mod->module) 2530 module_put(btf_mod->module); 2531 btf_put(btf_mod->btf); 2532 } 2533 #endif 2534 } 2535 2536 static void bpf_free_used_btfs(struct bpf_prog_aux *aux) 2537 { 2538 __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt); 2539 kfree(aux->used_btfs); 2540 } 2541 2542 static void bpf_prog_free_deferred(struct work_struct *work) 2543 { 2544 struct bpf_prog_aux *aux; 2545 int i; 2546 2547 aux = container_of(work, struct bpf_prog_aux, work); 2548 #ifdef CONFIG_BPF_SYSCALL 2549 bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab); 2550 #endif 2551 #ifdef CONFIG_CGROUP_BPF 2552 if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID) 2553 bpf_cgroup_atype_put(aux->cgroup_atype); 2554 #endif 2555 bpf_free_used_maps(aux); 2556 bpf_free_used_btfs(aux); 2557 if (bpf_prog_is_dev_bound(aux)) 2558 bpf_prog_offload_destroy(aux->prog); 2559 #ifdef CONFIG_PERF_EVENTS 2560 if (aux->prog->has_callchain_buf) 2561 put_callchain_buffers(); 2562 #endif 2563 if (aux->dst_trampoline) 2564 bpf_trampoline_put(aux->dst_trampoline); 2565 for (i = 0; i < aux->func_cnt; i++) { 2566 /* We can just unlink the subprog poke descriptor table as 2567 * it was originally linked to the main program and is also 2568 * released along with it. 2569 */ 2570 aux->func[i]->aux->poke_tab = NULL; 2571 bpf_jit_free(aux->func[i]); 2572 } 2573 if (aux->func_cnt) { 2574 kfree(aux->func); 2575 bpf_prog_unlock_free(aux->prog); 2576 } else { 2577 bpf_jit_free(aux->prog); 2578 } 2579 } 2580 2581 void bpf_prog_free(struct bpf_prog *fp) 2582 { 2583 struct bpf_prog_aux *aux = fp->aux; 2584 2585 if (aux->dst_prog) 2586 bpf_prog_put(aux->dst_prog); 2587 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2588 schedule_work(&aux->work); 2589 } 2590 EXPORT_SYMBOL_GPL(bpf_prog_free); 2591 2592 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 2593 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2594 2595 void bpf_user_rnd_init_once(void) 2596 { 2597 prandom_init_once(&bpf_user_rnd_state); 2598 } 2599 2600 BPF_CALL_0(bpf_user_rnd_u32) 2601 { 2602 /* Should someone ever have the rather unwise idea to use some 2603 * of the registers passed into this function, then note that 2604 * this function is called from native eBPF and classic-to-eBPF 2605 * transformations. Register assignments from both sides are 2606 * different, f.e. classic always sets fn(ctx, A, X) here. 2607 */ 2608 struct rnd_state *state; 2609 u32 res; 2610 2611 state = &get_cpu_var(bpf_user_rnd_state); 2612 res = prandom_u32_state(state); 2613 put_cpu_var(bpf_user_rnd_state); 2614 2615 return res; 2616 } 2617 2618 BPF_CALL_0(bpf_get_raw_cpu_id) 2619 { 2620 return raw_smp_processor_id(); 2621 } 2622 2623 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2624 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2625 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2626 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2627 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2628 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2629 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2630 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak; 2631 const struct bpf_func_proto bpf_spin_lock_proto __weak; 2632 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 2633 const struct bpf_func_proto bpf_jiffies64_proto __weak; 2634 2635 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2636 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2637 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2638 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2639 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 2640 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak; 2641 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak; 2642 2643 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2644 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2645 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2646 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2647 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 2648 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2649 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 2650 const struct bpf_func_proto bpf_snprintf_btf_proto __weak; 2651 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; 2652 const struct bpf_func_proto bpf_set_retval_proto __weak; 2653 const struct bpf_func_proto bpf_get_retval_proto __weak; 2654 2655 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2656 { 2657 return NULL; 2658 } 2659 2660 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void) 2661 { 2662 return NULL; 2663 } 2664 2665 u64 __weak 2666 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2667 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2668 { 2669 return -ENOTSUPP; 2670 } 2671 EXPORT_SYMBOL_GPL(bpf_event_output); 2672 2673 /* Always built-in helper functions. */ 2674 const struct bpf_func_proto bpf_tail_call_proto = { 2675 .func = NULL, 2676 .gpl_only = false, 2677 .ret_type = RET_VOID, 2678 .arg1_type = ARG_PTR_TO_CTX, 2679 .arg2_type = ARG_CONST_MAP_PTR, 2680 .arg3_type = ARG_ANYTHING, 2681 }; 2682 2683 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 2684 * It is encouraged to implement bpf_int_jit_compile() instead, so that 2685 * eBPF and implicitly also cBPF can get JITed! 2686 */ 2687 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 2688 { 2689 return prog; 2690 } 2691 2692 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 2693 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 2694 */ 2695 void __weak bpf_jit_compile(struct bpf_prog *prog) 2696 { 2697 } 2698 2699 bool __weak bpf_helper_changes_pkt_data(void *func) 2700 { 2701 return false; 2702 } 2703 2704 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 2705 * analysis code and wants explicit zero extension inserted by verifier. 2706 * Otherwise, return FALSE. 2707 * 2708 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if 2709 * you don't override this. JITs that don't want these extra insns can detect 2710 * them using insn_is_zext. 2711 */ 2712 bool __weak bpf_jit_needs_zext(void) 2713 { 2714 return false; 2715 } 2716 2717 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ 2718 bool __weak bpf_jit_supports_subprog_tailcalls(void) 2719 { 2720 return false; 2721 } 2722 2723 bool __weak bpf_jit_supports_kfunc_call(void) 2724 { 2725 return false; 2726 } 2727 2728 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 2729 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 2730 */ 2731 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 2732 int len) 2733 { 2734 return -EFAULT; 2735 } 2736 2737 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, 2738 void *addr1, void *addr2) 2739 { 2740 return -ENOTSUPP; 2741 } 2742 2743 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len) 2744 { 2745 return ERR_PTR(-ENOTSUPP); 2746 } 2747 2748 int __weak bpf_arch_text_invalidate(void *dst, size_t len) 2749 { 2750 return -ENOTSUPP; 2751 } 2752 2753 #ifdef CONFIG_BPF_SYSCALL 2754 static int __init bpf_global_ma_init(void) 2755 { 2756 int ret; 2757 2758 ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false); 2759 bpf_global_ma_set = !ret; 2760 return ret; 2761 } 2762 late_initcall(bpf_global_ma_init); 2763 #endif 2764 2765 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 2766 EXPORT_SYMBOL(bpf_stats_enabled_key); 2767 2768 /* All definitions of tracepoints related to BPF. */ 2769 #define CREATE_TRACE_POINTS 2770 #include <linux/bpf_trace.h> 2771 2772 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 2773 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 2774