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/nospec.h> 38 #include <linux/bpf_mem_alloc.h> 39 #include <linux/memcontrol.h> 40 41 #include <asm/barrier.h> 42 #include <asm/unaligned.h> 43 44 /* Registers */ 45 #define BPF_R0 regs[BPF_REG_0] 46 #define BPF_R1 regs[BPF_REG_1] 47 #define BPF_R2 regs[BPF_REG_2] 48 #define BPF_R3 regs[BPF_REG_3] 49 #define BPF_R4 regs[BPF_REG_4] 50 #define BPF_R5 regs[BPF_REG_5] 51 #define BPF_R6 regs[BPF_REG_6] 52 #define BPF_R7 regs[BPF_REG_7] 53 #define BPF_R8 regs[BPF_REG_8] 54 #define BPF_R9 regs[BPF_REG_9] 55 #define BPF_R10 regs[BPF_REG_10] 56 57 /* Named registers */ 58 #define DST regs[insn->dst_reg] 59 #define SRC regs[insn->src_reg] 60 #define FP regs[BPF_REG_FP] 61 #define AX regs[BPF_REG_AX] 62 #define ARG1 regs[BPF_REG_ARG1] 63 #define CTX regs[BPF_REG_CTX] 64 #define OFF insn->off 65 #define IMM insn->imm 66 67 struct bpf_mem_alloc bpf_global_ma; 68 bool bpf_global_ma_set; 69 70 /* No hurry in this branch 71 * 72 * Exported for the bpf jit load helper. 73 */ 74 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 75 { 76 u8 *ptr = NULL; 77 78 if (k >= SKF_NET_OFF) { 79 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 80 } else if (k >= SKF_LL_OFF) { 81 if (unlikely(!skb_mac_header_was_set(skb))) 82 return NULL; 83 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 84 } 85 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 86 return ptr; 87 88 return NULL; 89 } 90 91 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags) 92 { 93 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 94 struct bpf_prog_aux *aux; 95 struct bpf_prog *fp; 96 97 size = round_up(size, PAGE_SIZE); 98 fp = __vmalloc(size, gfp_flags); 99 if (fp == NULL) 100 return NULL; 101 102 aux = kzalloc(sizeof(*aux), bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags)); 103 if (aux == NULL) { 104 vfree(fp); 105 return NULL; 106 } 107 fp->active = alloc_percpu_gfp(int, bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags)); 108 if (!fp->active) { 109 vfree(fp); 110 kfree(aux); 111 return NULL; 112 } 113 114 fp->pages = size / PAGE_SIZE; 115 fp->aux = aux; 116 fp->aux->prog = fp; 117 fp->jit_requested = ebpf_jit_enabled(); 118 fp->blinding_requested = bpf_jit_blinding_enabled(fp); 119 #ifdef CONFIG_CGROUP_BPF 120 aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID; 121 #endif 122 123 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); 124 mutex_init(&fp->aux->used_maps_mutex); 125 mutex_init(&fp->aux->dst_mutex); 126 127 return fp; 128 } 129 130 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 131 { 132 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 133 struct bpf_prog *prog; 134 int cpu; 135 136 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); 137 if (!prog) 138 return NULL; 139 140 prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); 141 if (!prog->stats) { 142 free_percpu(prog->active); 143 kfree(prog->aux); 144 vfree(prog); 145 return NULL; 146 } 147 148 for_each_possible_cpu(cpu) { 149 struct bpf_prog_stats *pstats; 150 151 pstats = per_cpu_ptr(prog->stats, cpu); 152 u64_stats_init(&pstats->syncp); 153 } 154 return prog; 155 } 156 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 157 158 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 159 { 160 if (!prog->aux->nr_linfo || !prog->jit_requested) 161 return 0; 162 163 prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo, 164 sizeof(*prog->aux->jited_linfo), 165 bpf_memcg_flags(GFP_KERNEL | __GFP_NOWARN)); 166 if (!prog->aux->jited_linfo) 167 return -ENOMEM; 168 169 return 0; 170 } 171 172 void bpf_prog_jit_attempt_done(struct bpf_prog *prog) 173 { 174 if (prog->aux->jited_linfo && 175 (!prog->jited || !prog->aux->jited_linfo[0])) { 176 kvfree(prog->aux->jited_linfo); 177 prog->aux->jited_linfo = NULL; 178 } 179 180 kfree(prog->aux->kfunc_tab); 181 prog->aux->kfunc_tab = NULL; 182 } 183 184 /* The jit engine is responsible to provide an array 185 * for insn_off to the jited_off mapping (insn_to_jit_off). 186 * 187 * The idx to this array is the insn_off. Hence, the insn_off 188 * here is relative to the prog itself instead of the main prog. 189 * This array has one entry for each xlated bpf insn. 190 * 191 * jited_off is the byte off to the end of the jited insn. 192 * 193 * Hence, with 194 * insn_start: 195 * The first bpf insn off of the prog. The insn off 196 * here is relative to the main prog. 197 * e.g. if prog is a subprog, insn_start > 0 198 * linfo_idx: 199 * The prog's idx to prog->aux->linfo and jited_linfo 200 * 201 * jited_linfo[linfo_idx] = prog->bpf_func 202 * 203 * For i > linfo_idx, 204 * 205 * jited_linfo[i] = prog->bpf_func + 206 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 207 */ 208 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 209 const u32 *insn_to_jit_off) 210 { 211 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 212 const struct bpf_line_info *linfo; 213 void **jited_linfo; 214 215 if (!prog->aux->jited_linfo) 216 /* Userspace did not provide linfo */ 217 return; 218 219 linfo_idx = prog->aux->linfo_idx; 220 linfo = &prog->aux->linfo[linfo_idx]; 221 insn_start = linfo[0].insn_off; 222 insn_end = insn_start + prog->len; 223 224 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 225 jited_linfo[0] = prog->bpf_func; 226 227 nr_linfo = prog->aux->nr_linfo - linfo_idx; 228 229 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 230 /* The verifier ensures that linfo[i].insn_off is 231 * strictly increasing 232 */ 233 jited_linfo[i] = prog->bpf_func + 234 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 235 } 236 237 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 238 gfp_t gfp_extra_flags) 239 { 240 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 241 struct bpf_prog *fp; 242 u32 pages; 243 244 size = round_up(size, PAGE_SIZE); 245 pages = size / PAGE_SIZE; 246 if (pages <= fp_old->pages) 247 return fp_old; 248 249 fp = __vmalloc(size, gfp_flags); 250 if (fp) { 251 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 252 fp->pages = pages; 253 fp->aux->prog = fp; 254 255 /* We keep fp->aux from fp_old around in the new 256 * reallocated structure. 257 */ 258 fp_old->aux = NULL; 259 fp_old->stats = NULL; 260 fp_old->active = NULL; 261 __bpf_prog_free(fp_old); 262 } 263 264 return fp; 265 } 266 267 void __bpf_prog_free(struct bpf_prog *fp) 268 { 269 if (fp->aux) { 270 mutex_destroy(&fp->aux->used_maps_mutex); 271 mutex_destroy(&fp->aux->dst_mutex); 272 kfree(fp->aux->poke_tab); 273 kfree(fp->aux); 274 } 275 free_percpu(fp->stats); 276 free_percpu(fp->active); 277 vfree(fp); 278 } 279 280 int bpf_prog_calc_tag(struct bpf_prog *fp) 281 { 282 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64); 283 u32 raw_size = bpf_prog_tag_scratch_size(fp); 284 u32 digest[SHA1_DIGEST_WORDS]; 285 u32 ws[SHA1_WORKSPACE_WORDS]; 286 u32 i, bsize, psize, blocks; 287 struct bpf_insn *dst; 288 bool was_ld_map; 289 u8 *raw, *todo; 290 __be32 *result; 291 __be64 *bits; 292 293 raw = vmalloc(raw_size); 294 if (!raw) 295 return -ENOMEM; 296 297 sha1_init(digest); 298 memset(ws, 0, sizeof(ws)); 299 300 /* We need to take out the map fd for the digest calculation 301 * since they are unstable from user space side. 302 */ 303 dst = (void *)raw; 304 for (i = 0, was_ld_map = false; i < fp->len; i++) { 305 dst[i] = fp->insnsi[i]; 306 if (!was_ld_map && 307 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 308 (dst[i].src_reg == BPF_PSEUDO_MAP_FD || 309 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { 310 was_ld_map = true; 311 dst[i].imm = 0; 312 } else if (was_ld_map && 313 dst[i].code == 0 && 314 dst[i].dst_reg == 0 && 315 dst[i].src_reg == 0 && 316 dst[i].off == 0) { 317 was_ld_map = false; 318 dst[i].imm = 0; 319 } else { 320 was_ld_map = false; 321 } 322 } 323 324 psize = bpf_prog_insn_size(fp); 325 memset(&raw[psize], 0, raw_size - psize); 326 raw[psize++] = 0x80; 327 328 bsize = round_up(psize, SHA1_BLOCK_SIZE); 329 blocks = bsize / SHA1_BLOCK_SIZE; 330 todo = raw; 331 if (bsize - psize >= sizeof(__be64)) { 332 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 333 } else { 334 bits = (__be64 *)(todo + bsize + bits_offset); 335 blocks++; 336 } 337 *bits = cpu_to_be64((psize - 1) << 3); 338 339 while (blocks--) { 340 sha1_transform(digest, todo, ws); 341 todo += SHA1_BLOCK_SIZE; 342 } 343 344 result = (__force __be32 *)digest; 345 for (i = 0; i < SHA1_DIGEST_WORDS; i++) 346 result[i] = cpu_to_be32(digest[i]); 347 memcpy(fp->tag, result, sizeof(fp->tag)); 348 349 vfree(raw); 350 return 0; 351 } 352 353 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, 354 s32 end_new, s32 curr, const bool probe_pass) 355 { 356 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 357 s32 delta = end_new - end_old; 358 s64 imm = insn->imm; 359 360 if (curr < pos && curr + imm + 1 >= end_old) 361 imm += delta; 362 else if (curr >= end_new && curr + imm + 1 < end_new) 363 imm -= delta; 364 if (imm < imm_min || imm > imm_max) 365 return -ERANGE; 366 if (!probe_pass) 367 insn->imm = imm; 368 return 0; 369 } 370 371 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, 372 s32 end_new, s32 curr, const bool probe_pass) 373 { 374 const s32 off_min = S16_MIN, off_max = S16_MAX; 375 s32 delta = end_new - end_old; 376 s32 off; 377 378 if (insn->code == (BPF_JMP32 | BPF_JA)) 379 off = insn->imm; 380 else 381 off = insn->off; 382 383 if (curr < pos && curr + off + 1 >= end_old) 384 off += delta; 385 else if (curr >= end_new && curr + off + 1 < end_new) 386 off -= delta; 387 if (off < off_min || off > off_max) 388 return -ERANGE; 389 if (!probe_pass) { 390 if (insn->code == (BPF_JMP32 | BPF_JA)) 391 insn->imm = off; 392 else 393 insn->off = off; 394 } 395 return 0; 396 } 397 398 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 399 s32 end_new, const bool probe_pass) 400 { 401 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); 402 struct bpf_insn *insn = prog->insnsi; 403 int ret = 0; 404 405 for (i = 0; i < insn_cnt; i++, insn++) { 406 u8 code; 407 408 /* In the probing pass we still operate on the original, 409 * unpatched image in order to check overflows before we 410 * do any other adjustments. Therefore skip the patchlet. 411 */ 412 if (probe_pass && i == pos) { 413 i = end_new; 414 insn = prog->insnsi + end_old; 415 } 416 if (bpf_pseudo_func(insn)) { 417 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 418 end_new, i, probe_pass); 419 if (ret) 420 return ret; 421 continue; 422 } 423 code = insn->code; 424 if ((BPF_CLASS(code) != BPF_JMP && 425 BPF_CLASS(code) != BPF_JMP32) || 426 BPF_OP(code) == BPF_EXIT) 427 continue; 428 /* Adjust offset of jmps if we cross patch boundaries. */ 429 if (BPF_OP(code) == BPF_CALL) { 430 if (insn->src_reg != BPF_PSEUDO_CALL) 431 continue; 432 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 433 end_new, i, probe_pass); 434 } else { 435 ret = bpf_adj_delta_to_off(insn, pos, end_old, 436 end_new, i, probe_pass); 437 } 438 if (ret) 439 break; 440 } 441 442 return ret; 443 } 444 445 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 446 { 447 struct bpf_line_info *linfo; 448 u32 i, nr_linfo; 449 450 nr_linfo = prog->aux->nr_linfo; 451 if (!nr_linfo || !delta) 452 return; 453 454 linfo = prog->aux->linfo; 455 456 for (i = 0; i < nr_linfo; i++) 457 if (off < linfo[i].insn_off) 458 break; 459 460 /* Push all off < linfo[i].insn_off by delta */ 461 for (; i < nr_linfo; i++) 462 linfo[i].insn_off += delta; 463 } 464 465 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 466 const struct bpf_insn *patch, u32 len) 467 { 468 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 469 const u32 cnt_max = S16_MAX; 470 struct bpf_prog *prog_adj; 471 int err; 472 473 /* Since our patchlet doesn't expand the image, we're done. */ 474 if (insn_delta == 0) { 475 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 476 return prog; 477 } 478 479 insn_adj_cnt = prog->len + insn_delta; 480 481 /* Reject anything that would potentially let the insn->off 482 * target overflow when we have excessive program expansions. 483 * We need to probe here before we do any reallocation where 484 * we afterwards may not fail anymore. 485 */ 486 if (insn_adj_cnt > cnt_max && 487 (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) 488 return ERR_PTR(err); 489 490 /* Several new instructions need to be inserted. Make room 491 * for them. Likely, there's no need for a new allocation as 492 * last page could have large enough tailroom. 493 */ 494 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 495 GFP_USER); 496 if (!prog_adj) 497 return ERR_PTR(-ENOMEM); 498 499 prog_adj->len = insn_adj_cnt; 500 501 /* Patching happens in 3 steps: 502 * 503 * 1) Move over tail of insnsi from next instruction onwards, 504 * so we can patch the single target insn with one or more 505 * new ones (patching is always from 1 to n insns, n > 0). 506 * 2) Inject new instructions at the target location. 507 * 3) Adjust branch offsets if necessary. 508 */ 509 insn_rest = insn_adj_cnt - off - len; 510 511 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 512 sizeof(*patch) * insn_rest); 513 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 514 515 /* We are guaranteed to not fail at this point, otherwise 516 * the ship has sailed to reverse to the original state. An 517 * overflow cannot happen at this point. 518 */ 519 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); 520 521 bpf_adj_linfo(prog_adj, off, insn_delta); 522 523 return prog_adj; 524 } 525 526 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) 527 { 528 /* Branch offsets can't overflow when program is shrinking, no need 529 * to call bpf_adj_branches(..., true) here 530 */ 531 memmove(prog->insnsi + off, prog->insnsi + off + cnt, 532 sizeof(struct bpf_insn) * (prog->len - off - cnt)); 533 prog->len -= cnt; 534 535 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); 536 } 537 538 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 539 { 540 int i; 541 542 for (i = 0; i < fp->aux->func_cnt; i++) 543 bpf_prog_kallsyms_del(fp->aux->func[i]); 544 } 545 546 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 547 { 548 bpf_prog_kallsyms_del_subprogs(fp); 549 bpf_prog_kallsyms_del(fp); 550 } 551 552 #ifdef CONFIG_BPF_JIT 553 /* All BPF JIT sysctl knobs here. */ 554 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 555 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 556 int bpf_jit_harden __read_mostly; 557 long bpf_jit_limit __read_mostly; 558 long bpf_jit_limit_max __read_mostly; 559 560 static void 561 bpf_prog_ksym_set_addr(struct bpf_prog *prog) 562 { 563 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 564 565 prog->aux->ksym.start = (unsigned long) prog->bpf_func; 566 prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len; 567 } 568 569 static void 570 bpf_prog_ksym_set_name(struct bpf_prog *prog) 571 { 572 char *sym = prog->aux->ksym.name; 573 const char *end = sym + KSYM_NAME_LEN; 574 const struct btf_type *type; 575 const char *func_name; 576 577 BUILD_BUG_ON(sizeof("bpf_prog_") + 578 sizeof(prog->tag) * 2 + 579 /* name has been null terminated. 580 * We should need +1 for the '_' preceding 581 * the name. However, the null character 582 * is double counted between the name and the 583 * sizeof("bpf_prog_") above, so we omit 584 * the +1 here. 585 */ 586 sizeof(prog->aux->name) > KSYM_NAME_LEN); 587 588 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 589 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 590 591 /* prog->aux->name will be ignored if full btf name is available */ 592 if (prog->aux->func_info_cnt) { 593 type = btf_type_by_id(prog->aux->btf, 594 prog->aux->func_info[prog->aux->func_idx].type_id); 595 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 596 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 597 return; 598 } 599 600 if (prog->aux->name[0]) 601 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 602 else 603 *sym = 0; 604 } 605 606 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) 607 { 608 return container_of(n, struct bpf_ksym, tnode)->start; 609 } 610 611 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 612 struct latch_tree_node *b) 613 { 614 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); 615 } 616 617 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 618 { 619 unsigned long val = (unsigned long)key; 620 const struct bpf_ksym *ksym; 621 622 ksym = container_of(n, struct bpf_ksym, tnode); 623 624 if (val < ksym->start) 625 return -1; 626 if (val >= ksym->end) 627 return 1; 628 629 return 0; 630 } 631 632 static const struct latch_tree_ops bpf_tree_ops = { 633 .less = bpf_tree_less, 634 .comp = bpf_tree_comp, 635 }; 636 637 static DEFINE_SPINLOCK(bpf_lock); 638 static LIST_HEAD(bpf_kallsyms); 639 static struct latch_tree_root bpf_tree __cacheline_aligned; 640 641 void bpf_ksym_add(struct bpf_ksym *ksym) 642 { 643 spin_lock_bh(&bpf_lock); 644 WARN_ON_ONCE(!list_empty(&ksym->lnode)); 645 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); 646 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 647 spin_unlock_bh(&bpf_lock); 648 } 649 650 static void __bpf_ksym_del(struct bpf_ksym *ksym) 651 { 652 if (list_empty(&ksym->lnode)) 653 return; 654 655 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 656 list_del_rcu(&ksym->lnode); 657 } 658 659 void bpf_ksym_del(struct bpf_ksym *ksym) 660 { 661 spin_lock_bh(&bpf_lock); 662 __bpf_ksym_del(ksym); 663 spin_unlock_bh(&bpf_lock); 664 } 665 666 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 667 { 668 return fp->jited && !bpf_prog_was_classic(fp); 669 } 670 671 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 672 { 673 if (!bpf_prog_kallsyms_candidate(fp) || 674 !bpf_capable()) 675 return; 676 677 bpf_prog_ksym_set_addr(fp); 678 bpf_prog_ksym_set_name(fp); 679 fp->aux->ksym.prog = true; 680 681 bpf_ksym_add(&fp->aux->ksym); 682 } 683 684 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 685 { 686 if (!bpf_prog_kallsyms_candidate(fp)) 687 return; 688 689 bpf_ksym_del(&fp->aux->ksym); 690 } 691 692 static struct bpf_ksym *bpf_ksym_find(unsigned long addr) 693 { 694 struct latch_tree_node *n; 695 696 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 697 return n ? container_of(n, struct bpf_ksym, tnode) : NULL; 698 } 699 700 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, 701 unsigned long *off, char *sym) 702 { 703 struct bpf_ksym *ksym; 704 char *ret = NULL; 705 706 rcu_read_lock(); 707 ksym = bpf_ksym_find(addr); 708 if (ksym) { 709 unsigned long symbol_start = ksym->start; 710 unsigned long symbol_end = ksym->end; 711 712 strncpy(sym, ksym->name, KSYM_NAME_LEN); 713 714 ret = sym; 715 if (size) 716 *size = symbol_end - symbol_start; 717 if (off) 718 *off = addr - symbol_start; 719 } 720 rcu_read_unlock(); 721 722 return ret; 723 } 724 725 bool is_bpf_text_address(unsigned long addr) 726 { 727 bool ret; 728 729 rcu_read_lock(); 730 ret = bpf_ksym_find(addr) != NULL; 731 rcu_read_unlock(); 732 733 return ret; 734 } 735 736 static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) 737 { 738 struct bpf_ksym *ksym = bpf_ksym_find(addr); 739 740 return ksym && ksym->prog ? 741 container_of(ksym, struct bpf_prog_aux, ksym)->prog : 742 NULL; 743 } 744 745 const struct exception_table_entry *search_bpf_extables(unsigned long addr) 746 { 747 const struct exception_table_entry *e = NULL; 748 struct bpf_prog *prog; 749 750 rcu_read_lock(); 751 prog = bpf_prog_ksym_find(addr); 752 if (!prog) 753 goto out; 754 if (!prog->aux->num_exentries) 755 goto out; 756 757 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); 758 out: 759 rcu_read_unlock(); 760 return e; 761 } 762 763 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 764 char *sym) 765 { 766 struct bpf_ksym *ksym; 767 unsigned int it = 0; 768 int ret = -ERANGE; 769 770 if (!bpf_jit_kallsyms_enabled()) 771 return ret; 772 773 rcu_read_lock(); 774 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { 775 if (it++ != symnum) 776 continue; 777 778 strncpy(sym, ksym->name, KSYM_NAME_LEN); 779 780 *value = ksym->start; 781 *type = BPF_SYM_ELF_TYPE; 782 783 ret = 0; 784 break; 785 } 786 rcu_read_unlock(); 787 788 return ret; 789 } 790 791 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, 792 struct bpf_jit_poke_descriptor *poke) 793 { 794 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; 795 static const u32 poke_tab_max = 1024; 796 u32 slot = prog->aux->size_poke_tab; 797 u32 size = slot + 1; 798 799 if (size > poke_tab_max) 800 return -ENOSPC; 801 if (poke->tailcall_target || poke->tailcall_target_stable || 802 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) 803 return -EINVAL; 804 805 switch (poke->reason) { 806 case BPF_POKE_REASON_TAIL_CALL: 807 if (!poke->tail_call.map) 808 return -EINVAL; 809 break; 810 default: 811 return -EINVAL; 812 } 813 814 tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL); 815 if (!tab) 816 return -ENOMEM; 817 818 memcpy(&tab[slot], poke, sizeof(*poke)); 819 prog->aux->size_poke_tab = size; 820 prog->aux->poke_tab = tab; 821 822 return slot; 823 } 824 825 /* 826 * BPF program pack allocator. 827 * 828 * Most BPF programs are pretty small. Allocating a hole page for each 829 * program is sometime a waste. Many small bpf program also adds pressure 830 * to instruction TLB. To solve this issue, we introduce a BPF program pack 831 * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86) 832 * to host BPF programs. 833 */ 834 #define BPF_PROG_CHUNK_SHIFT 6 835 #define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT) 836 #define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1)) 837 838 struct bpf_prog_pack { 839 struct list_head list; 840 void *ptr; 841 unsigned long bitmap[]; 842 }; 843 844 void bpf_jit_fill_hole_with_zero(void *area, unsigned int size) 845 { 846 memset(area, 0, size); 847 } 848 849 #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) 850 851 static DEFINE_MUTEX(pack_mutex); 852 static LIST_HEAD(pack_list); 853 854 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with 855 * CONFIG_MMU=n. Use PAGE_SIZE in these cases. 856 */ 857 #ifdef PMD_SIZE 858 #define BPF_PROG_PACK_SIZE (PMD_SIZE * num_possible_nodes()) 859 #else 860 #define BPF_PROG_PACK_SIZE PAGE_SIZE 861 #endif 862 863 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE) 864 865 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) 866 { 867 struct bpf_prog_pack *pack; 868 869 pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)), 870 GFP_KERNEL); 871 if (!pack) 872 return NULL; 873 pack->ptr = bpf_jit_alloc_exec(BPF_PROG_PACK_SIZE); 874 if (!pack->ptr) { 875 kfree(pack); 876 return NULL; 877 } 878 bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE); 879 bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE); 880 list_add_tail(&pack->list, &pack_list); 881 882 set_vm_flush_reset_perms(pack->ptr); 883 set_memory_rox((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); 884 return pack; 885 } 886 887 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) 888 { 889 unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); 890 struct bpf_prog_pack *pack; 891 unsigned long pos; 892 void *ptr = NULL; 893 894 mutex_lock(&pack_mutex); 895 if (size > BPF_PROG_PACK_SIZE) { 896 size = round_up(size, PAGE_SIZE); 897 ptr = bpf_jit_alloc_exec(size); 898 if (ptr) { 899 bpf_fill_ill_insns(ptr, size); 900 set_vm_flush_reset_perms(ptr); 901 set_memory_rox((unsigned long)ptr, size / PAGE_SIZE); 902 } 903 goto out; 904 } 905 list_for_each_entry(pack, &pack_list, list) { 906 pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 907 nbits, 0); 908 if (pos < BPF_PROG_CHUNK_COUNT) 909 goto found_free_area; 910 } 911 912 pack = alloc_new_pack(bpf_fill_ill_insns); 913 if (!pack) 914 goto out; 915 916 pos = 0; 917 918 found_free_area: 919 bitmap_set(pack->bitmap, pos, nbits); 920 ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT); 921 922 out: 923 mutex_unlock(&pack_mutex); 924 return ptr; 925 } 926 927 void bpf_prog_pack_free(struct bpf_binary_header *hdr) 928 { 929 struct bpf_prog_pack *pack = NULL, *tmp; 930 unsigned int nbits; 931 unsigned long pos; 932 933 mutex_lock(&pack_mutex); 934 if (hdr->size > BPF_PROG_PACK_SIZE) { 935 bpf_jit_free_exec(hdr); 936 goto out; 937 } 938 939 list_for_each_entry(tmp, &pack_list, list) { 940 if ((void *)hdr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > (void *)hdr) { 941 pack = tmp; 942 break; 943 } 944 } 945 946 if (WARN_ONCE(!pack, "bpf_prog_pack bug\n")) 947 goto out; 948 949 nbits = BPF_PROG_SIZE_TO_NBITS(hdr->size); 950 pos = ((unsigned long)hdr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT; 951 952 WARN_ONCE(bpf_arch_text_invalidate(hdr, hdr->size), 953 "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n"); 954 955 bitmap_clear(pack->bitmap, pos, nbits); 956 if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 957 BPF_PROG_CHUNK_COUNT, 0) == 0) { 958 list_del(&pack->list); 959 bpf_jit_free_exec(pack->ptr); 960 kfree(pack); 961 } 962 out: 963 mutex_unlock(&pack_mutex); 964 } 965 966 static atomic_long_t bpf_jit_current; 967 968 /* Can be overridden by an arch's JIT compiler if it has a custom, 969 * dedicated BPF backend memory area, or if neither of the two 970 * below apply. 971 */ 972 u64 __weak bpf_jit_alloc_exec_limit(void) 973 { 974 #if defined(MODULES_VADDR) 975 return MODULES_END - MODULES_VADDR; 976 #else 977 return VMALLOC_END - VMALLOC_START; 978 #endif 979 } 980 981 static int __init bpf_jit_charge_init(void) 982 { 983 /* Only used as heuristic here to derive limit. */ 984 bpf_jit_limit_max = bpf_jit_alloc_exec_limit(); 985 bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 1, 986 PAGE_SIZE), LONG_MAX); 987 return 0; 988 } 989 pure_initcall(bpf_jit_charge_init); 990 991 int bpf_jit_charge_modmem(u32 size) 992 { 993 if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) { 994 if (!bpf_capable()) { 995 atomic_long_sub(size, &bpf_jit_current); 996 return -EPERM; 997 } 998 } 999 1000 return 0; 1001 } 1002 1003 void bpf_jit_uncharge_modmem(u32 size) 1004 { 1005 atomic_long_sub(size, &bpf_jit_current); 1006 } 1007 1008 void *__weak bpf_jit_alloc_exec(unsigned long size) 1009 { 1010 return module_alloc(size); 1011 } 1012 1013 void __weak bpf_jit_free_exec(void *addr) 1014 { 1015 module_memfree(addr); 1016 } 1017 1018 struct bpf_binary_header * 1019 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 1020 unsigned int alignment, 1021 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1022 { 1023 struct bpf_binary_header *hdr; 1024 u32 size, hole, start; 1025 1026 WARN_ON_ONCE(!is_power_of_2(alignment) || 1027 alignment > BPF_IMAGE_ALIGNMENT); 1028 1029 /* Most of BPF filters are really small, but if some of them 1030 * fill a page, allow at least 128 extra bytes to insert a 1031 * random section of illegal instructions. 1032 */ 1033 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 1034 1035 if (bpf_jit_charge_modmem(size)) 1036 return NULL; 1037 hdr = bpf_jit_alloc_exec(size); 1038 if (!hdr) { 1039 bpf_jit_uncharge_modmem(size); 1040 return NULL; 1041 } 1042 1043 /* Fill space with illegal/arch-dep instructions. */ 1044 bpf_fill_ill_insns(hdr, size); 1045 1046 hdr->size = size; 1047 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 1048 PAGE_SIZE - sizeof(*hdr)); 1049 start = get_random_u32_below(hole) & ~(alignment - 1); 1050 1051 /* Leave a random number of instructions before BPF code. */ 1052 *image_ptr = &hdr->image[start]; 1053 1054 return hdr; 1055 } 1056 1057 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 1058 { 1059 u32 size = hdr->size; 1060 1061 bpf_jit_free_exec(hdr); 1062 bpf_jit_uncharge_modmem(size); 1063 } 1064 1065 /* Allocate jit binary from bpf_prog_pack allocator. 1066 * Since the allocated memory is RO+X, the JIT engine cannot write directly 1067 * to the memory. To solve this problem, a RW buffer is also allocated at 1068 * as the same time. The JIT engine should calculate offsets based on the 1069 * RO memory address, but write JITed program to the RW buffer. Once the 1070 * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies 1071 * the JITed program to the RO memory. 1072 */ 1073 struct bpf_binary_header * 1074 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr, 1075 unsigned int alignment, 1076 struct bpf_binary_header **rw_header, 1077 u8 **rw_image, 1078 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1079 { 1080 struct bpf_binary_header *ro_header; 1081 u32 size, hole, start; 1082 1083 WARN_ON_ONCE(!is_power_of_2(alignment) || 1084 alignment > BPF_IMAGE_ALIGNMENT); 1085 1086 /* add 16 bytes for a random section of illegal instructions */ 1087 size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE); 1088 1089 if (bpf_jit_charge_modmem(size)) 1090 return NULL; 1091 ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns); 1092 if (!ro_header) { 1093 bpf_jit_uncharge_modmem(size); 1094 return NULL; 1095 } 1096 1097 *rw_header = kvmalloc(size, GFP_KERNEL); 1098 if (!*rw_header) { 1099 bpf_arch_text_copy(&ro_header->size, &size, sizeof(size)); 1100 bpf_prog_pack_free(ro_header); 1101 bpf_jit_uncharge_modmem(size); 1102 return NULL; 1103 } 1104 1105 /* Fill space with illegal/arch-dep instructions. */ 1106 bpf_fill_ill_insns(*rw_header, size); 1107 (*rw_header)->size = size; 1108 1109 hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)), 1110 BPF_PROG_CHUNK_SIZE - sizeof(*ro_header)); 1111 start = get_random_u32_below(hole) & ~(alignment - 1); 1112 1113 *image_ptr = &ro_header->image[start]; 1114 *rw_image = &(*rw_header)->image[start]; 1115 1116 return ro_header; 1117 } 1118 1119 /* Copy JITed text from rw_header to its final location, the ro_header. */ 1120 int bpf_jit_binary_pack_finalize(struct bpf_prog *prog, 1121 struct bpf_binary_header *ro_header, 1122 struct bpf_binary_header *rw_header) 1123 { 1124 void *ptr; 1125 1126 ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size); 1127 1128 kvfree(rw_header); 1129 1130 if (IS_ERR(ptr)) { 1131 bpf_prog_pack_free(ro_header); 1132 return PTR_ERR(ptr); 1133 } 1134 return 0; 1135 } 1136 1137 /* bpf_jit_binary_pack_free is called in two different scenarios: 1138 * 1) when the program is freed after; 1139 * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize). 1140 * For case 2), we need to free both the RO memory and the RW buffer. 1141 * 1142 * bpf_jit_binary_pack_free requires proper ro_header->size. However, 1143 * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size 1144 * must be set with either bpf_jit_binary_pack_finalize (normal path) or 1145 * bpf_arch_text_copy (when jit fails). 1146 */ 1147 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header, 1148 struct bpf_binary_header *rw_header) 1149 { 1150 u32 size = ro_header->size; 1151 1152 bpf_prog_pack_free(ro_header); 1153 kvfree(rw_header); 1154 bpf_jit_uncharge_modmem(size); 1155 } 1156 1157 struct bpf_binary_header * 1158 bpf_jit_binary_pack_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 & BPF_PROG_CHUNK_MASK; 1164 return (void *)addr; 1165 } 1166 1167 static inline struct bpf_binary_header * 1168 bpf_jit_binary_hdr(const struct bpf_prog *fp) 1169 { 1170 unsigned long real_start = (unsigned long)fp->bpf_func; 1171 unsigned long addr; 1172 1173 addr = real_start & PAGE_MASK; 1174 return (void *)addr; 1175 } 1176 1177 /* This symbol is only overridden by archs that have different 1178 * requirements than the usual eBPF JITs, f.e. when they only 1179 * implement cBPF JIT, do not set images read-only, etc. 1180 */ 1181 void __weak bpf_jit_free(struct bpf_prog *fp) 1182 { 1183 if (fp->jited) { 1184 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 1185 1186 bpf_jit_binary_free(hdr); 1187 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 1188 } 1189 1190 bpf_prog_unlock_free(fp); 1191 } 1192 1193 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 1194 const struct bpf_insn *insn, bool extra_pass, 1195 u64 *func_addr, bool *func_addr_fixed) 1196 { 1197 s16 off = insn->off; 1198 s32 imm = insn->imm; 1199 u8 *addr; 1200 int err; 1201 1202 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 1203 if (!*func_addr_fixed) { 1204 /* Place-holder address till the last pass has collected 1205 * all addresses for JITed subprograms in which case we 1206 * can pick them up from prog->aux. 1207 */ 1208 if (!extra_pass) 1209 addr = NULL; 1210 else if (prog->aux->func && 1211 off >= 0 && off < prog->aux->func_cnt) 1212 addr = (u8 *)prog->aux->func[off]->bpf_func; 1213 else 1214 return -EINVAL; 1215 } else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && 1216 bpf_jit_supports_far_kfunc_call()) { 1217 err = bpf_get_kfunc_addr(prog, insn->imm, insn->off, &addr); 1218 if (err) 1219 return err; 1220 } else { 1221 /* Address of a BPF helper call. Since part of the core 1222 * kernel, it's always at a fixed location. __bpf_call_base 1223 * and the helper with imm relative to it are both in core 1224 * kernel. 1225 */ 1226 addr = (u8 *)__bpf_call_base + imm; 1227 } 1228 1229 *func_addr = (unsigned long)addr; 1230 return 0; 1231 } 1232 1233 static int bpf_jit_blind_insn(const struct bpf_insn *from, 1234 const struct bpf_insn *aux, 1235 struct bpf_insn *to_buff, 1236 bool emit_zext) 1237 { 1238 struct bpf_insn *to = to_buff; 1239 u32 imm_rnd = get_random_u32(); 1240 s16 off; 1241 1242 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 1243 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 1244 1245 /* Constraints on AX register: 1246 * 1247 * AX register is inaccessible from user space. It is mapped in 1248 * all JITs, and used here for constant blinding rewrites. It is 1249 * typically "stateless" meaning its contents are only valid within 1250 * the executed instruction, but not across several instructions. 1251 * There are a few exceptions however which are further detailed 1252 * below. 1253 * 1254 * Constant blinding is only used by JITs, not in the interpreter. 1255 * The interpreter uses AX in some occasions as a local temporary 1256 * register e.g. in DIV or MOD instructions. 1257 * 1258 * In restricted circumstances, the verifier can also use the AX 1259 * register for rewrites as long as they do not interfere with 1260 * the above cases! 1261 */ 1262 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 1263 goto out; 1264 1265 if (from->imm == 0 && 1266 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 1267 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 1268 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 1269 goto out; 1270 } 1271 1272 switch (from->code) { 1273 case BPF_ALU | BPF_ADD | BPF_K: 1274 case BPF_ALU | BPF_SUB | BPF_K: 1275 case BPF_ALU | BPF_AND | BPF_K: 1276 case BPF_ALU | BPF_OR | BPF_K: 1277 case BPF_ALU | BPF_XOR | BPF_K: 1278 case BPF_ALU | BPF_MUL | BPF_K: 1279 case BPF_ALU | BPF_MOV | BPF_K: 1280 case BPF_ALU | BPF_DIV | BPF_K: 1281 case BPF_ALU | BPF_MOD | BPF_K: 1282 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1283 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1284 *to++ = BPF_ALU32_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off); 1285 break; 1286 1287 case BPF_ALU64 | BPF_ADD | BPF_K: 1288 case BPF_ALU64 | BPF_SUB | BPF_K: 1289 case BPF_ALU64 | BPF_AND | BPF_K: 1290 case BPF_ALU64 | BPF_OR | BPF_K: 1291 case BPF_ALU64 | BPF_XOR | BPF_K: 1292 case BPF_ALU64 | BPF_MUL | BPF_K: 1293 case BPF_ALU64 | BPF_MOV | BPF_K: 1294 case BPF_ALU64 | BPF_DIV | BPF_K: 1295 case BPF_ALU64 | BPF_MOD | BPF_K: 1296 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1297 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1298 *to++ = BPF_ALU64_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off); 1299 break; 1300 1301 case BPF_JMP | BPF_JEQ | BPF_K: 1302 case BPF_JMP | BPF_JNE | BPF_K: 1303 case BPF_JMP | BPF_JGT | BPF_K: 1304 case BPF_JMP | BPF_JLT | BPF_K: 1305 case BPF_JMP | BPF_JGE | BPF_K: 1306 case BPF_JMP | BPF_JLE | BPF_K: 1307 case BPF_JMP | BPF_JSGT | BPF_K: 1308 case BPF_JMP | BPF_JSLT | BPF_K: 1309 case BPF_JMP | BPF_JSGE | BPF_K: 1310 case BPF_JMP | BPF_JSLE | BPF_K: 1311 case BPF_JMP | BPF_JSET | BPF_K: 1312 /* Accommodate for extra offset in case of a backjump. */ 1313 off = from->off; 1314 if (off < 0) 1315 off -= 2; 1316 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1317 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1318 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1319 break; 1320 1321 case BPF_JMP32 | BPF_JEQ | BPF_K: 1322 case BPF_JMP32 | BPF_JNE | BPF_K: 1323 case BPF_JMP32 | BPF_JGT | BPF_K: 1324 case BPF_JMP32 | BPF_JLT | BPF_K: 1325 case BPF_JMP32 | BPF_JGE | BPF_K: 1326 case BPF_JMP32 | BPF_JLE | BPF_K: 1327 case BPF_JMP32 | BPF_JSGT | BPF_K: 1328 case BPF_JMP32 | BPF_JSLT | BPF_K: 1329 case BPF_JMP32 | BPF_JSGE | BPF_K: 1330 case BPF_JMP32 | BPF_JSLE | BPF_K: 1331 case BPF_JMP32 | BPF_JSET | BPF_K: 1332 /* Accommodate for extra offset in case of a backjump. */ 1333 off = from->off; 1334 if (off < 0) 1335 off -= 2; 1336 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1337 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1338 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1339 off); 1340 break; 1341 1342 case BPF_LD | BPF_IMM | BPF_DW: 1343 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1344 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1345 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1346 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1347 break; 1348 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1349 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1350 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1351 if (emit_zext) 1352 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1353 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1354 break; 1355 1356 case BPF_ST | BPF_MEM | BPF_DW: 1357 case BPF_ST | BPF_MEM | BPF_W: 1358 case BPF_ST | BPF_MEM | BPF_H: 1359 case BPF_ST | BPF_MEM | BPF_B: 1360 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1361 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1362 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1363 break; 1364 } 1365 out: 1366 return to - to_buff; 1367 } 1368 1369 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1370 gfp_t gfp_extra_flags) 1371 { 1372 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1373 struct bpf_prog *fp; 1374 1375 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1376 if (fp != NULL) { 1377 /* aux->prog still points to the fp_other one, so 1378 * when promoting the clone to the real program, 1379 * this still needs to be adapted. 1380 */ 1381 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1382 } 1383 1384 return fp; 1385 } 1386 1387 static void bpf_prog_clone_free(struct bpf_prog *fp) 1388 { 1389 /* aux was stolen by the other clone, so we cannot free 1390 * it from this path! It will be freed eventually by the 1391 * other program on release. 1392 * 1393 * At this point, we don't need a deferred release since 1394 * clone is guaranteed to not be locked. 1395 */ 1396 fp->aux = NULL; 1397 fp->stats = NULL; 1398 fp->active = NULL; 1399 __bpf_prog_free(fp); 1400 } 1401 1402 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1403 { 1404 /* We have to repoint aux->prog to self, as we don't 1405 * know whether fp here is the clone or the original. 1406 */ 1407 fp->aux->prog = fp; 1408 bpf_prog_clone_free(fp_other); 1409 } 1410 1411 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1412 { 1413 struct bpf_insn insn_buff[16], aux[2]; 1414 struct bpf_prog *clone, *tmp; 1415 int insn_delta, insn_cnt; 1416 struct bpf_insn *insn; 1417 int i, rewritten; 1418 1419 if (!prog->blinding_requested || prog->blinded) 1420 return prog; 1421 1422 clone = bpf_prog_clone_create(prog, GFP_USER); 1423 if (!clone) 1424 return ERR_PTR(-ENOMEM); 1425 1426 insn_cnt = clone->len; 1427 insn = clone->insnsi; 1428 1429 for (i = 0; i < insn_cnt; i++, insn++) { 1430 if (bpf_pseudo_func(insn)) { 1431 /* ld_imm64 with an address of bpf subprog is not 1432 * a user controlled constant. Don't randomize it, 1433 * since it will conflict with jit_subprogs() logic. 1434 */ 1435 insn++; 1436 i++; 1437 continue; 1438 } 1439 1440 /* We temporarily need to hold the original ld64 insn 1441 * so that we can still access the first part in the 1442 * second blinding run. 1443 */ 1444 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1445 insn[1].code == 0) 1446 memcpy(aux, insn, sizeof(aux)); 1447 1448 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1449 clone->aux->verifier_zext); 1450 if (!rewritten) 1451 continue; 1452 1453 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1454 if (IS_ERR(tmp)) { 1455 /* Patching may have repointed aux->prog during 1456 * realloc from the original one, so we need to 1457 * fix it up here on error. 1458 */ 1459 bpf_jit_prog_release_other(prog, clone); 1460 return tmp; 1461 } 1462 1463 clone = tmp; 1464 insn_delta = rewritten - 1; 1465 1466 /* Walk new program and skip insns we just inserted. */ 1467 insn = clone->insnsi + i + insn_delta; 1468 insn_cnt += insn_delta; 1469 i += insn_delta; 1470 } 1471 1472 clone->blinded = 1; 1473 return clone; 1474 } 1475 #endif /* CONFIG_BPF_JIT */ 1476 1477 /* Base function for offset calculation. Needs to go into .text section, 1478 * therefore keeping it non-static as well; will also be used by JITs 1479 * anyway later on, so do not let the compiler omit it. This also needs 1480 * to go into kallsyms for correlation from e.g. bpftool, so naming 1481 * must not change. 1482 */ 1483 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1484 { 1485 return 0; 1486 } 1487 EXPORT_SYMBOL_GPL(__bpf_call_base); 1488 1489 /* All UAPI available opcodes. */ 1490 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1491 /* 32 bit ALU operations. */ \ 1492 /* Register based. */ \ 1493 INSN_3(ALU, ADD, X), \ 1494 INSN_3(ALU, SUB, X), \ 1495 INSN_3(ALU, AND, X), \ 1496 INSN_3(ALU, OR, X), \ 1497 INSN_3(ALU, LSH, X), \ 1498 INSN_3(ALU, RSH, X), \ 1499 INSN_3(ALU, XOR, X), \ 1500 INSN_3(ALU, MUL, X), \ 1501 INSN_3(ALU, MOV, X), \ 1502 INSN_3(ALU, ARSH, X), \ 1503 INSN_3(ALU, DIV, X), \ 1504 INSN_3(ALU, MOD, X), \ 1505 INSN_2(ALU, NEG), \ 1506 INSN_3(ALU, END, TO_BE), \ 1507 INSN_3(ALU, END, TO_LE), \ 1508 /* Immediate based. */ \ 1509 INSN_3(ALU, ADD, K), \ 1510 INSN_3(ALU, SUB, K), \ 1511 INSN_3(ALU, AND, K), \ 1512 INSN_3(ALU, OR, K), \ 1513 INSN_3(ALU, LSH, K), \ 1514 INSN_3(ALU, RSH, K), \ 1515 INSN_3(ALU, XOR, K), \ 1516 INSN_3(ALU, MUL, K), \ 1517 INSN_3(ALU, MOV, K), \ 1518 INSN_3(ALU, ARSH, K), \ 1519 INSN_3(ALU, DIV, K), \ 1520 INSN_3(ALU, MOD, K), \ 1521 /* 64 bit ALU operations. */ \ 1522 /* Register based. */ \ 1523 INSN_3(ALU64, ADD, X), \ 1524 INSN_3(ALU64, SUB, X), \ 1525 INSN_3(ALU64, AND, X), \ 1526 INSN_3(ALU64, OR, X), \ 1527 INSN_3(ALU64, LSH, X), \ 1528 INSN_3(ALU64, RSH, X), \ 1529 INSN_3(ALU64, XOR, X), \ 1530 INSN_3(ALU64, MUL, X), \ 1531 INSN_3(ALU64, MOV, X), \ 1532 INSN_3(ALU64, ARSH, X), \ 1533 INSN_3(ALU64, DIV, X), \ 1534 INSN_3(ALU64, MOD, X), \ 1535 INSN_2(ALU64, NEG), \ 1536 INSN_3(ALU64, END, TO_LE), \ 1537 /* Immediate based. */ \ 1538 INSN_3(ALU64, ADD, K), \ 1539 INSN_3(ALU64, SUB, K), \ 1540 INSN_3(ALU64, AND, K), \ 1541 INSN_3(ALU64, OR, K), \ 1542 INSN_3(ALU64, LSH, K), \ 1543 INSN_3(ALU64, RSH, K), \ 1544 INSN_3(ALU64, XOR, K), \ 1545 INSN_3(ALU64, MUL, K), \ 1546 INSN_3(ALU64, MOV, K), \ 1547 INSN_3(ALU64, ARSH, K), \ 1548 INSN_3(ALU64, DIV, K), \ 1549 INSN_3(ALU64, MOD, K), \ 1550 /* Call instruction. */ \ 1551 INSN_2(JMP, CALL), \ 1552 /* Exit instruction. */ \ 1553 INSN_2(JMP, EXIT), \ 1554 /* 32-bit Jump instructions. */ \ 1555 /* Register based. */ \ 1556 INSN_3(JMP32, JEQ, X), \ 1557 INSN_3(JMP32, JNE, X), \ 1558 INSN_3(JMP32, JGT, X), \ 1559 INSN_3(JMP32, JLT, X), \ 1560 INSN_3(JMP32, JGE, X), \ 1561 INSN_3(JMP32, JLE, X), \ 1562 INSN_3(JMP32, JSGT, X), \ 1563 INSN_3(JMP32, JSLT, X), \ 1564 INSN_3(JMP32, JSGE, X), \ 1565 INSN_3(JMP32, JSLE, X), \ 1566 INSN_3(JMP32, JSET, X), \ 1567 /* Immediate based. */ \ 1568 INSN_3(JMP32, JEQ, K), \ 1569 INSN_3(JMP32, JNE, K), \ 1570 INSN_3(JMP32, JGT, K), \ 1571 INSN_3(JMP32, JLT, K), \ 1572 INSN_3(JMP32, JGE, K), \ 1573 INSN_3(JMP32, JLE, K), \ 1574 INSN_3(JMP32, JSGT, K), \ 1575 INSN_3(JMP32, JSLT, K), \ 1576 INSN_3(JMP32, JSGE, K), \ 1577 INSN_3(JMP32, JSLE, K), \ 1578 INSN_3(JMP32, JSET, K), \ 1579 /* Jump instructions. */ \ 1580 /* Register based. */ \ 1581 INSN_3(JMP, JEQ, X), \ 1582 INSN_3(JMP, JNE, X), \ 1583 INSN_3(JMP, JGT, X), \ 1584 INSN_3(JMP, JLT, X), \ 1585 INSN_3(JMP, JGE, X), \ 1586 INSN_3(JMP, JLE, X), \ 1587 INSN_3(JMP, JSGT, X), \ 1588 INSN_3(JMP, JSLT, X), \ 1589 INSN_3(JMP, JSGE, X), \ 1590 INSN_3(JMP, JSLE, X), \ 1591 INSN_3(JMP, JSET, X), \ 1592 /* Immediate based. */ \ 1593 INSN_3(JMP, JEQ, K), \ 1594 INSN_3(JMP, JNE, K), \ 1595 INSN_3(JMP, JGT, K), \ 1596 INSN_3(JMP, JLT, K), \ 1597 INSN_3(JMP, JGE, K), \ 1598 INSN_3(JMP, JLE, K), \ 1599 INSN_3(JMP, JSGT, K), \ 1600 INSN_3(JMP, JSLT, K), \ 1601 INSN_3(JMP, JSGE, K), \ 1602 INSN_3(JMP, JSLE, K), \ 1603 INSN_3(JMP, JSET, K), \ 1604 INSN_2(JMP, JA), \ 1605 INSN_2(JMP32, JA), \ 1606 /* Store instructions. */ \ 1607 /* Register based. */ \ 1608 INSN_3(STX, MEM, B), \ 1609 INSN_3(STX, MEM, H), \ 1610 INSN_3(STX, MEM, W), \ 1611 INSN_3(STX, MEM, DW), \ 1612 INSN_3(STX, ATOMIC, W), \ 1613 INSN_3(STX, ATOMIC, DW), \ 1614 /* Immediate based. */ \ 1615 INSN_3(ST, MEM, B), \ 1616 INSN_3(ST, MEM, H), \ 1617 INSN_3(ST, MEM, W), \ 1618 INSN_3(ST, MEM, DW), \ 1619 /* Load instructions. */ \ 1620 /* Register based. */ \ 1621 INSN_3(LDX, MEM, B), \ 1622 INSN_3(LDX, MEM, H), \ 1623 INSN_3(LDX, MEM, W), \ 1624 INSN_3(LDX, MEM, DW), \ 1625 INSN_3(LDX, MEMSX, B), \ 1626 INSN_3(LDX, MEMSX, H), \ 1627 INSN_3(LDX, MEMSX, W), \ 1628 /* Immediate based. */ \ 1629 INSN_3(LD, IMM, DW) 1630 1631 bool bpf_opcode_in_insntable(u8 code) 1632 { 1633 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1634 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1635 static const bool public_insntable[256] = { 1636 [0 ... 255] = false, 1637 /* Now overwrite non-defaults ... */ 1638 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1639 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1640 [BPF_LD | BPF_ABS | BPF_B] = true, 1641 [BPF_LD | BPF_ABS | BPF_H] = true, 1642 [BPF_LD | BPF_ABS | BPF_W] = true, 1643 [BPF_LD | BPF_IND | BPF_B] = true, 1644 [BPF_LD | BPF_IND | BPF_H] = true, 1645 [BPF_LD | BPF_IND | BPF_W] = true, 1646 }; 1647 #undef BPF_INSN_3_TBL 1648 #undef BPF_INSN_2_TBL 1649 return public_insntable[code]; 1650 } 1651 1652 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1653 /** 1654 * ___bpf_prog_run - run eBPF program on a given context 1655 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1656 * @insn: is the array of eBPF instructions 1657 * 1658 * Decode and execute eBPF instructions. 1659 * 1660 * Return: whatever value is in %BPF_R0 at program exit 1661 */ 1662 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) 1663 { 1664 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1665 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1666 static const void * const jumptable[256] __annotate_jump_table = { 1667 [0 ... 255] = &&default_label, 1668 /* Now overwrite non-defaults ... */ 1669 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1670 /* Non-UAPI available opcodes. */ 1671 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1672 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1673 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC, 1674 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1675 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1676 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1677 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1678 [BPF_LDX | BPF_PROBE_MEMSX | BPF_B] = &&LDX_PROBE_MEMSX_B, 1679 [BPF_LDX | BPF_PROBE_MEMSX | BPF_H] = &&LDX_PROBE_MEMSX_H, 1680 [BPF_LDX | BPF_PROBE_MEMSX | BPF_W] = &&LDX_PROBE_MEMSX_W, 1681 }; 1682 #undef BPF_INSN_3_LBL 1683 #undef BPF_INSN_2_LBL 1684 u32 tail_call_cnt = 0; 1685 1686 #define CONT ({ insn++; goto select_insn; }) 1687 #define CONT_JMP ({ insn++; goto select_insn; }) 1688 1689 select_insn: 1690 goto *jumptable[insn->code]; 1691 1692 /* Explicitly mask the register-based shift amounts with 63 or 31 1693 * to avoid undefined behavior. Normally this won't affect the 1694 * generated code, for example, in case of native 64 bit archs such 1695 * as x86-64 or arm64, the compiler is optimizing the AND away for 1696 * the interpreter. In case of JITs, each of the JIT backends compiles 1697 * the BPF shift operations to machine instructions which produce 1698 * implementation-defined results in such a case; the resulting 1699 * contents of the register may be arbitrary, but program behaviour 1700 * as a whole remains defined. In other words, in case of JIT backends, 1701 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation. 1702 */ 1703 /* ALU (shifts) */ 1704 #define SHT(OPCODE, OP) \ 1705 ALU64_##OPCODE##_X: \ 1706 DST = DST OP (SRC & 63); \ 1707 CONT; \ 1708 ALU_##OPCODE##_X: \ 1709 DST = (u32) DST OP ((u32) SRC & 31); \ 1710 CONT; \ 1711 ALU64_##OPCODE##_K: \ 1712 DST = DST OP IMM; \ 1713 CONT; \ 1714 ALU_##OPCODE##_K: \ 1715 DST = (u32) DST OP (u32) IMM; \ 1716 CONT; 1717 /* ALU (rest) */ 1718 #define ALU(OPCODE, OP) \ 1719 ALU64_##OPCODE##_X: \ 1720 DST = DST OP SRC; \ 1721 CONT; \ 1722 ALU_##OPCODE##_X: \ 1723 DST = (u32) DST OP (u32) SRC; \ 1724 CONT; \ 1725 ALU64_##OPCODE##_K: \ 1726 DST = DST OP IMM; \ 1727 CONT; \ 1728 ALU_##OPCODE##_K: \ 1729 DST = (u32) DST OP (u32) IMM; \ 1730 CONT; 1731 ALU(ADD, +) 1732 ALU(SUB, -) 1733 ALU(AND, &) 1734 ALU(OR, |) 1735 ALU(XOR, ^) 1736 ALU(MUL, *) 1737 SHT(LSH, <<) 1738 SHT(RSH, >>) 1739 #undef SHT 1740 #undef ALU 1741 ALU_NEG: 1742 DST = (u32) -DST; 1743 CONT; 1744 ALU64_NEG: 1745 DST = -DST; 1746 CONT; 1747 ALU_MOV_X: 1748 switch (OFF) { 1749 case 0: 1750 DST = (u32) SRC; 1751 break; 1752 case 8: 1753 DST = (u32)(s8) SRC; 1754 break; 1755 case 16: 1756 DST = (u32)(s16) SRC; 1757 break; 1758 } 1759 CONT; 1760 ALU_MOV_K: 1761 DST = (u32) IMM; 1762 CONT; 1763 ALU64_MOV_X: 1764 switch (OFF) { 1765 case 0: 1766 DST = SRC; 1767 break; 1768 case 8: 1769 DST = (s8) SRC; 1770 break; 1771 case 16: 1772 DST = (s16) SRC; 1773 break; 1774 case 32: 1775 DST = (s32) SRC; 1776 break; 1777 } 1778 CONT; 1779 ALU64_MOV_K: 1780 DST = IMM; 1781 CONT; 1782 LD_IMM_DW: 1783 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1784 insn++; 1785 CONT; 1786 ALU_ARSH_X: 1787 DST = (u64) (u32) (((s32) DST) >> (SRC & 31)); 1788 CONT; 1789 ALU_ARSH_K: 1790 DST = (u64) (u32) (((s32) DST) >> IMM); 1791 CONT; 1792 ALU64_ARSH_X: 1793 (*(s64 *) &DST) >>= (SRC & 63); 1794 CONT; 1795 ALU64_ARSH_K: 1796 (*(s64 *) &DST) >>= IMM; 1797 CONT; 1798 ALU64_MOD_X: 1799 switch (OFF) { 1800 case 0: 1801 div64_u64_rem(DST, SRC, &AX); 1802 DST = AX; 1803 break; 1804 case 1: 1805 AX = div64_s64(DST, SRC); 1806 DST = DST - AX * SRC; 1807 break; 1808 } 1809 CONT; 1810 ALU_MOD_X: 1811 switch (OFF) { 1812 case 0: 1813 AX = (u32) DST; 1814 DST = do_div(AX, (u32) SRC); 1815 break; 1816 case 1: 1817 AX = abs((s32)DST); 1818 AX = do_div(AX, abs((s32)SRC)); 1819 if ((s32)DST < 0) 1820 DST = (u32)-AX; 1821 else 1822 DST = (u32)AX; 1823 break; 1824 } 1825 CONT; 1826 ALU64_MOD_K: 1827 switch (OFF) { 1828 case 0: 1829 div64_u64_rem(DST, IMM, &AX); 1830 DST = AX; 1831 break; 1832 case 1: 1833 AX = div64_s64(DST, IMM); 1834 DST = DST - AX * IMM; 1835 break; 1836 } 1837 CONT; 1838 ALU_MOD_K: 1839 switch (OFF) { 1840 case 0: 1841 AX = (u32) DST; 1842 DST = do_div(AX, (u32) IMM); 1843 break; 1844 case 1: 1845 AX = abs((s32)DST); 1846 AX = do_div(AX, abs((s32)IMM)); 1847 if ((s32)DST < 0) 1848 DST = (u32)-AX; 1849 else 1850 DST = (u32)AX; 1851 break; 1852 } 1853 CONT; 1854 ALU64_DIV_X: 1855 switch (OFF) { 1856 case 0: 1857 DST = div64_u64(DST, SRC); 1858 break; 1859 case 1: 1860 DST = div64_s64(DST, SRC); 1861 break; 1862 } 1863 CONT; 1864 ALU_DIV_X: 1865 switch (OFF) { 1866 case 0: 1867 AX = (u32) DST; 1868 do_div(AX, (u32) SRC); 1869 DST = (u32) AX; 1870 break; 1871 case 1: 1872 AX = abs((s32)DST); 1873 do_div(AX, abs((s32)SRC)); 1874 if (((s32)DST < 0) == ((s32)SRC < 0)) 1875 DST = (u32)AX; 1876 else 1877 DST = (u32)-AX; 1878 break; 1879 } 1880 CONT; 1881 ALU64_DIV_K: 1882 switch (OFF) { 1883 case 0: 1884 DST = div64_u64(DST, IMM); 1885 break; 1886 case 1: 1887 DST = div64_s64(DST, IMM); 1888 break; 1889 } 1890 CONT; 1891 ALU_DIV_K: 1892 switch (OFF) { 1893 case 0: 1894 AX = (u32) DST; 1895 do_div(AX, (u32) IMM); 1896 DST = (u32) AX; 1897 break; 1898 case 1: 1899 AX = abs((s32)DST); 1900 do_div(AX, abs((s32)IMM)); 1901 if (((s32)DST < 0) == ((s32)IMM < 0)) 1902 DST = (u32)AX; 1903 else 1904 DST = (u32)-AX; 1905 break; 1906 } 1907 CONT; 1908 ALU_END_TO_BE: 1909 switch (IMM) { 1910 case 16: 1911 DST = (__force u16) cpu_to_be16(DST); 1912 break; 1913 case 32: 1914 DST = (__force u32) cpu_to_be32(DST); 1915 break; 1916 case 64: 1917 DST = (__force u64) cpu_to_be64(DST); 1918 break; 1919 } 1920 CONT; 1921 ALU_END_TO_LE: 1922 switch (IMM) { 1923 case 16: 1924 DST = (__force u16) cpu_to_le16(DST); 1925 break; 1926 case 32: 1927 DST = (__force u32) cpu_to_le32(DST); 1928 break; 1929 case 64: 1930 DST = (__force u64) cpu_to_le64(DST); 1931 break; 1932 } 1933 CONT; 1934 ALU64_END_TO_LE: 1935 switch (IMM) { 1936 case 16: 1937 DST = (__force u16) __swab16(DST); 1938 break; 1939 case 32: 1940 DST = (__force u32) __swab32(DST); 1941 break; 1942 case 64: 1943 DST = (__force u64) __swab64(DST); 1944 break; 1945 } 1946 CONT; 1947 1948 /* CALL */ 1949 JMP_CALL: 1950 /* Function call scratches BPF_R1-BPF_R5 registers, 1951 * preserves BPF_R6-BPF_R9, and stores return value 1952 * into BPF_R0. 1953 */ 1954 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1955 BPF_R4, BPF_R5); 1956 CONT; 1957 1958 JMP_CALL_ARGS: 1959 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 1960 BPF_R3, BPF_R4, 1961 BPF_R5, 1962 insn + insn->off + 1); 1963 CONT; 1964 1965 JMP_TAIL_CALL: { 1966 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1967 struct bpf_array *array = container_of(map, struct bpf_array, map); 1968 struct bpf_prog *prog; 1969 u32 index = BPF_R3; 1970 1971 if (unlikely(index >= array->map.max_entries)) 1972 goto out; 1973 1974 if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT)) 1975 goto out; 1976 1977 tail_call_cnt++; 1978 1979 prog = READ_ONCE(array->ptrs[index]); 1980 if (!prog) 1981 goto out; 1982 1983 /* ARG1 at this point is guaranteed to point to CTX from 1984 * the verifier side due to the fact that the tail call is 1985 * handled like a helper, that is, bpf_tail_call_proto, 1986 * where arg1_type is ARG_PTR_TO_CTX. 1987 */ 1988 insn = prog->insnsi; 1989 goto select_insn; 1990 out: 1991 CONT; 1992 } 1993 JMP_JA: 1994 insn += insn->off; 1995 CONT; 1996 JMP32_JA: 1997 insn += insn->imm; 1998 CONT; 1999 JMP_EXIT: 2000 return BPF_R0; 2001 /* JMP */ 2002 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 2003 JMP_##OPCODE##_X: \ 2004 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 2005 insn += insn->off; \ 2006 CONT_JMP; \ 2007 } \ 2008 CONT; \ 2009 JMP32_##OPCODE##_X: \ 2010 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 2011 insn += insn->off; \ 2012 CONT_JMP; \ 2013 } \ 2014 CONT; \ 2015 JMP_##OPCODE##_K: \ 2016 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 2017 insn += insn->off; \ 2018 CONT_JMP; \ 2019 } \ 2020 CONT; \ 2021 JMP32_##OPCODE##_K: \ 2022 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 2023 insn += insn->off; \ 2024 CONT_JMP; \ 2025 } \ 2026 CONT; 2027 COND_JMP(u, JEQ, ==) 2028 COND_JMP(u, JNE, !=) 2029 COND_JMP(u, JGT, >) 2030 COND_JMP(u, JLT, <) 2031 COND_JMP(u, JGE, >=) 2032 COND_JMP(u, JLE, <=) 2033 COND_JMP(u, JSET, &) 2034 COND_JMP(s, JSGT, >) 2035 COND_JMP(s, JSLT, <) 2036 COND_JMP(s, JSGE, >=) 2037 COND_JMP(s, JSLE, <=) 2038 #undef COND_JMP 2039 /* ST, STX and LDX*/ 2040 ST_NOSPEC: 2041 /* Speculation barrier for mitigating Speculative Store Bypass. 2042 * In case of arm64, we rely on the firmware mitigation as 2043 * controlled via the ssbd kernel parameter. Whenever the 2044 * mitigation is enabled, it works for all of the kernel code 2045 * with no need to provide any additional instructions here. 2046 * In case of x86, we use 'lfence' insn for mitigation. We 2047 * reuse preexisting logic from Spectre v1 mitigation that 2048 * happens to produce the required code on x86 for v4 as well. 2049 */ 2050 barrier_nospec(); 2051 CONT; 2052 #define LDST(SIZEOP, SIZE) \ 2053 STX_MEM_##SIZEOP: \ 2054 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 2055 CONT; \ 2056 ST_MEM_##SIZEOP: \ 2057 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 2058 CONT; \ 2059 LDX_MEM_##SIZEOP: \ 2060 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 2061 CONT; \ 2062 LDX_PROBE_MEM_##SIZEOP: \ 2063 bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ 2064 (const void *)(long) (SRC + insn->off)); \ 2065 DST = *((SIZE *)&DST); \ 2066 CONT; 2067 2068 LDST(B, u8) 2069 LDST(H, u16) 2070 LDST(W, u32) 2071 LDST(DW, u64) 2072 #undef LDST 2073 2074 #define LDSX(SIZEOP, SIZE) \ 2075 LDX_MEMSX_##SIZEOP: \ 2076 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 2077 CONT; \ 2078 LDX_PROBE_MEMSX_##SIZEOP: \ 2079 bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ 2080 (const void *)(long) (SRC + insn->off)); \ 2081 DST = *((SIZE *)&DST); \ 2082 CONT; 2083 2084 LDSX(B, s8) 2085 LDSX(H, s16) 2086 LDSX(W, s32) 2087 #undef LDSX 2088 2089 #define ATOMIC_ALU_OP(BOP, KOP) \ 2090 case BOP: \ 2091 if (BPF_SIZE(insn->code) == BPF_W) \ 2092 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \ 2093 (DST + insn->off)); \ 2094 else \ 2095 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \ 2096 (DST + insn->off)); \ 2097 break; \ 2098 case BOP | BPF_FETCH: \ 2099 if (BPF_SIZE(insn->code) == BPF_W) \ 2100 SRC = (u32) atomic_fetch_##KOP( \ 2101 (u32) SRC, \ 2102 (atomic_t *)(unsigned long) (DST + insn->off)); \ 2103 else \ 2104 SRC = (u64) atomic64_fetch_##KOP( \ 2105 (u64) SRC, \ 2106 (atomic64_t *)(unsigned long) (DST + insn->off)); \ 2107 break; 2108 2109 STX_ATOMIC_DW: 2110 STX_ATOMIC_W: 2111 switch (IMM) { 2112 ATOMIC_ALU_OP(BPF_ADD, add) 2113 ATOMIC_ALU_OP(BPF_AND, and) 2114 ATOMIC_ALU_OP(BPF_OR, or) 2115 ATOMIC_ALU_OP(BPF_XOR, xor) 2116 #undef ATOMIC_ALU_OP 2117 2118 case BPF_XCHG: 2119 if (BPF_SIZE(insn->code) == BPF_W) 2120 SRC = (u32) atomic_xchg( 2121 (atomic_t *)(unsigned long) (DST + insn->off), 2122 (u32) SRC); 2123 else 2124 SRC = (u64) atomic64_xchg( 2125 (atomic64_t *)(unsigned long) (DST + insn->off), 2126 (u64) SRC); 2127 break; 2128 case BPF_CMPXCHG: 2129 if (BPF_SIZE(insn->code) == BPF_W) 2130 BPF_R0 = (u32) atomic_cmpxchg( 2131 (atomic_t *)(unsigned long) (DST + insn->off), 2132 (u32) BPF_R0, (u32) SRC); 2133 else 2134 BPF_R0 = (u64) atomic64_cmpxchg( 2135 (atomic64_t *)(unsigned long) (DST + insn->off), 2136 (u64) BPF_R0, (u64) SRC); 2137 break; 2138 2139 default: 2140 goto default_label; 2141 } 2142 CONT; 2143 2144 default_label: 2145 /* If we ever reach this, we have a bug somewhere. Die hard here 2146 * instead of just returning 0; we could be somewhere in a subprog, 2147 * so execution could continue otherwise which we do /not/ want. 2148 * 2149 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 2150 */ 2151 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n", 2152 insn->code, insn->imm); 2153 BUG_ON(1); 2154 return 0; 2155 } 2156 2157 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 2158 #define DEFINE_BPF_PROG_RUN(stack_size) \ 2159 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 2160 { \ 2161 u64 stack[stack_size / sizeof(u64)]; \ 2162 u64 regs[MAX_BPF_EXT_REG] = {}; \ 2163 \ 2164 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2165 ARG1 = (u64) (unsigned long) ctx; \ 2166 return ___bpf_prog_run(regs, insn); \ 2167 } 2168 2169 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 2170 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 2171 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 2172 const struct bpf_insn *insn) \ 2173 { \ 2174 u64 stack[stack_size / sizeof(u64)]; \ 2175 u64 regs[MAX_BPF_EXT_REG]; \ 2176 \ 2177 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2178 BPF_R1 = r1; \ 2179 BPF_R2 = r2; \ 2180 BPF_R3 = r3; \ 2181 BPF_R4 = r4; \ 2182 BPF_R5 = r5; \ 2183 return ___bpf_prog_run(regs, insn); \ 2184 } 2185 2186 #define EVAL1(FN, X) FN(X) 2187 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 2188 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 2189 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 2190 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 2191 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 2192 2193 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 2194 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 2195 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 2196 2197 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 2198 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 2199 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 2200 2201 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 2202 2203 static unsigned int (*interpreters[])(const void *ctx, 2204 const struct bpf_insn *insn) = { 2205 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2206 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2207 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2208 }; 2209 #undef PROG_NAME_LIST 2210 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 2211 static __maybe_unused 2212 u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 2213 const struct bpf_insn *insn) = { 2214 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2215 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2216 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2217 }; 2218 #undef PROG_NAME_LIST 2219 2220 #ifdef CONFIG_BPF_SYSCALL 2221 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 2222 { 2223 stack_depth = max_t(u32, stack_depth, 1); 2224 insn->off = (s16) insn->imm; 2225 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 2226 __bpf_call_base_args; 2227 insn->code = BPF_JMP | BPF_CALL_ARGS; 2228 } 2229 #endif 2230 #else 2231 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 2232 const struct bpf_insn *insn) 2233 { 2234 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 2235 * is not working properly, so warn about it! 2236 */ 2237 WARN_ON_ONCE(1); 2238 return 0; 2239 } 2240 #endif 2241 2242 bool bpf_prog_map_compatible(struct bpf_map *map, 2243 const struct bpf_prog *fp) 2244 { 2245 enum bpf_prog_type prog_type = resolve_prog_type(fp); 2246 bool ret; 2247 2248 if (fp->kprobe_override) 2249 return false; 2250 2251 /* XDP programs inserted into maps are not guaranteed to run on 2252 * a particular netdev (and can run outside driver context entirely 2253 * in the case of devmap and cpumap). Until device checks 2254 * are implemented, prohibit adding dev-bound programs to program maps. 2255 */ 2256 if (bpf_prog_is_dev_bound(fp->aux)) 2257 return false; 2258 2259 spin_lock(&map->owner.lock); 2260 if (!map->owner.type) { 2261 /* There's no owner yet where we could check for 2262 * compatibility. 2263 */ 2264 map->owner.type = prog_type; 2265 map->owner.jited = fp->jited; 2266 map->owner.xdp_has_frags = fp->aux->xdp_has_frags; 2267 ret = true; 2268 } else { 2269 ret = map->owner.type == prog_type && 2270 map->owner.jited == fp->jited && 2271 map->owner.xdp_has_frags == fp->aux->xdp_has_frags; 2272 } 2273 spin_unlock(&map->owner.lock); 2274 2275 return ret; 2276 } 2277 2278 static int bpf_check_tail_call(const struct bpf_prog *fp) 2279 { 2280 struct bpf_prog_aux *aux = fp->aux; 2281 int i, ret = 0; 2282 2283 mutex_lock(&aux->used_maps_mutex); 2284 for (i = 0; i < aux->used_map_cnt; i++) { 2285 struct bpf_map *map = aux->used_maps[i]; 2286 2287 if (!map_type_contains_progs(map)) 2288 continue; 2289 2290 if (!bpf_prog_map_compatible(map, fp)) { 2291 ret = -EINVAL; 2292 goto out; 2293 } 2294 } 2295 2296 out: 2297 mutex_unlock(&aux->used_maps_mutex); 2298 return ret; 2299 } 2300 2301 static void bpf_prog_select_func(struct bpf_prog *fp) 2302 { 2303 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 2304 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 2305 2306 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 2307 #else 2308 fp->bpf_func = __bpf_prog_ret0_warn; 2309 #endif 2310 } 2311 2312 /** 2313 * bpf_prog_select_runtime - select exec runtime for BPF program 2314 * @fp: bpf_prog populated with BPF program 2315 * @err: pointer to error variable 2316 * 2317 * Try to JIT eBPF program, if JIT is not available, use interpreter. 2318 * The BPF program will be executed via bpf_prog_run() function. 2319 * 2320 * Return: the &fp argument along with &err set to 0 for success or 2321 * a negative errno code on failure 2322 */ 2323 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 2324 { 2325 /* In case of BPF to BPF calls, verifier did all the prep 2326 * work with regards to JITing, etc. 2327 */ 2328 bool jit_needed = false; 2329 2330 if (fp->bpf_func) 2331 goto finalize; 2332 2333 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || 2334 bpf_prog_has_kfunc_call(fp)) 2335 jit_needed = true; 2336 2337 bpf_prog_select_func(fp); 2338 2339 /* eBPF JITs can rewrite the program in case constant 2340 * blinding is active. However, in case of error during 2341 * blinding, bpf_int_jit_compile() must always return a 2342 * valid program, which in this case would simply not 2343 * be JITed, but falls back to the interpreter. 2344 */ 2345 if (!bpf_prog_is_offloaded(fp->aux)) { 2346 *err = bpf_prog_alloc_jited_linfo(fp); 2347 if (*err) 2348 return fp; 2349 2350 fp = bpf_int_jit_compile(fp); 2351 bpf_prog_jit_attempt_done(fp); 2352 if (!fp->jited && jit_needed) { 2353 *err = -ENOTSUPP; 2354 return fp; 2355 } 2356 } else { 2357 *err = bpf_prog_offload_compile(fp); 2358 if (*err) 2359 return fp; 2360 } 2361 2362 finalize: 2363 bpf_prog_lock_ro(fp); 2364 2365 /* The tail call compatibility check can only be done at 2366 * this late stage as we need to determine, if we deal 2367 * with JITed or non JITed program concatenations and not 2368 * all eBPF JITs might immediately support all features. 2369 */ 2370 *err = bpf_check_tail_call(fp); 2371 2372 return fp; 2373 } 2374 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 2375 2376 static unsigned int __bpf_prog_ret1(const void *ctx, 2377 const struct bpf_insn *insn) 2378 { 2379 return 1; 2380 } 2381 2382 static struct bpf_prog_dummy { 2383 struct bpf_prog prog; 2384 } dummy_bpf_prog = { 2385 .prog = { 2386 .bpf_func = __bpf_prog_ret1, 2387 }, 2388 }; 2389 2390 struct bpf_empty_prog_array bpf_empty_prog_array = { 2391 .null_prog = NULL, 2392 }; 2393 EXPORT_SYMBOL(bpf_empty_prog_array); 2394 2395 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 2396 { 2397 if (prog_cnt) 2398 return kzalloc(sizeof(struct bpf_prog_array) + 2399 sizeof(struct bpf_prog_array_item) * 2400 (prog_cnt + 1), 2401 flags); 2402 2403 return &bpf_empty_prog_array.hdr; 2404 } 2405 2406 void bpf_prog_array_free(struct bpf_prog_array *progs) 2407 { 2408 if (!progs || progs == &bpf_empty_prog_array.hdr) 2409 return; 2410 kfree_rcu(progs, rcu); 2411 } 2412 2413 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu) 2414 { 2415 struct bpf_prog_array *progs; 2416 2417 /* If RCU Tasks Trace grace period implies RCU grace period, there is 2418 * no need to call kfree_rcu(), just call kfree() directly. 2419 */ 2420 progs = container_of(rcu, struct bpf_prog_array, rcu); 2421 if (rcu_trace_implies_rcu_gp()) 2422 kfree(progs); 2423 else 2424 kfree_rcu(progs, rcu); 2425 } 2426 2427 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs) 2428 { 2429 if (!progs || progs == &bpf_empty_prog_array.hdr) 2430 return; 2431 call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb); 2432 } 2433 2434 int bpf_prog_array_length(struct bpf_prog_array *array) 2435 { 2436 struct bpf_prog_array_item *item; 2437 u32 cnt = 0; 2438 2439 for (item = array->items; item->prog; item++) 2440 if (item->prog != &dummy_bpf_prog.prog) 2441 cnt++; 2442 return cnt; 2443 } 2444 2445 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 2446 { 2447 struct bpf_prog_array_item *item; 2448 2449 for (item = array->items; item->prog; item++) 2450 if (item->prog != &dummy_bpf_prog.prog) 2451 return false; 2452 return true; 2453 } 2454 2455 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 2456 u32 *prog_ids, 2457 u32 request_cnt) 2458 { 2459 struct bpf_prog_array_item *item; 2460 int i = 0; 2461 2462 for (item = array->items; item->prog; item++) { 2463 if (item->prog == &dummy_bpf_prog.prog) 2464 continue; 2465 prog_ids[i] = item->prog->aux->id; 2466 if (++i == request_cnt) { 2467 item++; 2468 break; 2469 } 2470 } 2471 2472 return !!(item->prog); 2473 } 2474 2475 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 2476 __u32 __user *prog_ids, u32 cnt) 2477 { 2478 unsigned long err = 0; 2479 bool nospc; 2480 u32 *ids; 2481 2482 /* users of this function are doing: 2483 * cnt = bpf_prog_array_length(); 2484 * if (cnt > 0) 2485 * bpf_prog_array_copy_to_user(..., cnt); 2486 * so below kcalloc doesn't need extra cnt > 0 check. 2487 */ 2488 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 2489 if (!ids) 2490 return -ENOMEM; 2491 nospc = bpf_prog_array_copy_core(array, ids, cnt); 2492 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 2493 kfree(ids); 2494 if (err) 2495 return -EFAULT; 2496 if (nospc) 2497 return -ENOSPC; 2498 return 0; 2499 } 2500 2501 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 2502 struct bpf_prog *old_prog) 2503 { 2504 struct bpf_prog_array_item *item; 2505 2506 for (item = array->items; item->prog; item++) 2507 if (item->prog == old_prog) { 2508 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 2509 break; 2510 } 2511 } 2512 2513 /** 2514 * bpf_prog_array_delete_safe_at() - Replaces the program at the given 2515 * index into the program array with 2516 * a dummy no-op program. 2517 * @array: a bpf_prog_array 2518 * @index: the index of the program to replace 2519 * 2520 * Skips over dummy programs, by not counting them, when calculating 2521 * the position of the program to replace. 2522 * 2523 * Return: 2524 * * 0 - Success 2525 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2526 * * -ENOENT - Index out of range 2527 */ 2528 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) 2529 { 2530 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); 2531 } 2532 2533 /** 2534 * bpf_prog_array_update_at() - Updates the program at the given index 2535 * into the program array. 2536 * @array: a bpf_prog_array 2537 * @index: the index of the program to update 2538 * @prog: the program to insert into the array 2539 * 2540 * Skips over dummy programs, by not counting them, when calculating 2541 * the position of the program to update. 2542 * 2543 * Return: 2544 * * 0 - Success 2545 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2546 * * -ENOENT - Index out of range 2547 */ 2548 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, 2549 struct bpf_prog *prog) 2550 { 2551 struct bpf_prog_array_item *item; 2552 2553 if (unlikely(index < 0)) 2554 return -EINVAL; 2555 2556 for (item = array->items; item->prog; item++) { 2557 if (item->prog == &dummy_bpf_prog.prog) 2558 continue; 2559 if (!index) { 2560 WRITE_ONCE(item->prog, prog); 2561 return 0; 2562 } 2563 index--; 2564 } 2565 return -ENOENT; 2566 } 2567 2568 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 2569 struct bpf_prog *exclude_prog, 2570 struct bpf_prog *include_prog, 2571 u64 bpf_cookie, 2572 struct bpf_prog_array **new_array) 2573 { 2574 int new_prog_cnt, carry_prog_cnt = 0; 2575 struct bpf_prog_array_item *existing, *new; 2576 struct bpf_prog_array *array; 2577 bool found_exclude = false; 2578 2579 /* Figure out how many existing progs we need to carry over to 2580 * the new array. 2581 */ 2582 if (old_array) { 2583 existing = old_array->items; 2584 for (; existing->prog; existing++) { 2585 if (existing->prog == exclude_prog) { 2586 found_exclude = true; 2587 continue; 2588 } 2589 if (existing->prog != &dummy_bpf_prog.prog) 2590 carry_prog_cnt++; 2591 if (existing->prog == include_prog) 2592 return -EEXIST; 2593 } 2594 } 2595 2596 if (exclude_prog && !found_exclude) 2597 return -ENOENT; 2598 2599 /* How many progs (not NULL) will be in the new array? */ 2600 new_prog_cnt = carry_prog_cnt; 2601 if (include_prog) 2602 new_prog_cnt += 1; 2603 2604 /* Do we have any prog (not NULL) in the new array? */ 2605 if (!new_prog_cnt) { 2606 *new_array = NULL; 2607 return 0; 2608 } 2609 2610 /* +1 as the end of prog_array is marked with NULL */ 2611 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2612 if (!array) 2613 return -ENOMEM; 2614 new = array->items; 2615 2616 /* Fill in the new prog array */ 2617 if (carry_prog_cnt) { 2618 existing = old_array->items; 2619 for (; existing->prog; existing++) { 2620 if (existing->prog == exclude_prog || 2621 existing->prog == &dummy_bpf_prog.prog) 2622 continue; 2623 2624 new->prog = existing->prog; 2625 new->bpf_cookie = existing->bpf_cookie; 2626 new++; 2627 } 2628 } 2629 if (include_prog) { 2630 new->prog = include_prog; 2631 new->bpf_cookie = bpf_cookie; 2632 new++; 2633 } 2634 new->prog = NULL; 2635 *new_array = array; 2636 return 0; 2637 } 2638 2639 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2640 u32 *prog_ids, u32 request_cnt, 2641 u32 *prog_cnt) 2642 { 2643 u32 cnt = 0; 2644 2645 if (array) 2646 cnt = bpf_prog_array_length(array); 2647 2648 *prog_cnt = cnt; 2649 2650 /* return early if user requested only program count or nothing to copy */ 2651 if (!request_cnt || !cnt) 2652 return 0; 2653 2654 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2655 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2656 : 0; 2657 } 2658 2659 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2660 struct bpf_map **used_maps, u32 len) 2661 { 2662 struct bpf_map *map; 2663 u32 i; 2664 2665 for (i = 0; i < len; i++) { 2666 map = used_maps[i]; 2667 if (map->ops->map_poke_untrack) 2668 map->ops->map_poke_untrack(map, aux); 2669 bpf_map_put(map); 2670 } 2671 } 2672 2673 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2674 { 2675 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2676 kfree(aux->used_maps); 2677 } 2678 2679 void __bpf_free_used_btfs(struct bpf_prog_aux *aux, 2680 struct btf_mod_pair *used_btfs, u32 len) 2681 { 2682 #ifdef CONFIG_BPF_SYSCALL 2683 struct btf_mod_pair *btf_mod; 2684 u32 i; 2685 2686 for (i = 0; i < len; i++) { 2687 btf_mod = &used_btfs[i]; 2688 if (btf_mod->module) 2689 module_put(btf_mod->module); 2690 btf_put(btf_mod->btf); 2691 } 2692 #endif 2693 } 2694 2695 static void bpf_free_used_btfs(struct bpf_prog_aux *aux) 2696 { 2697 __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt); 2698 kfree(aux->used_btfs); 2699 } 2700 2701 static void bpf_prog_free_deferred(struct work_struct *work) 2702 { 2703 struct bpf_prog_aux *aux; 2704 int i; 2705 2706 aux = container_of(work, struct bpf_prog_aux, work); 2707 #ifdef CONFIG_BPF_SYSCALL 2708 bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab); 2709 #endif 2710 #ifdef CONFIG_CGROUP_BPF 2711 if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID) 2712 bpf_cgroup_atype_put(aux->cgroup_atype); 2713 #endif 2714 bpf_free_used_maps(aux); 2715 bpf_free_used_btfs(aux); 2716 if (bpf_prog_is_dev_bound(aux)) 2717 bpf_prog_dev_bound_destroy(aux->prog); 2718 #ifdef CONFIG_PERF_EVENTS 2719 if (aux->prog->has_callchain_buf) 2720 put_callchain_buffers(); 2721 #endif 2722 if (aux->dst_trampoline) 2723 bpf_trampoline_put(aux->dst_trampoline); 2724 for (i = 0; i < aux->func_cnt; i++) { 2725 /* We can just unlink the subprog poke descriptor table as 2726 * it was originally linked to the main program and is also 2727 * released along with it. 2728 */ 2729 aux->func[i]->aux->poke_tab = NULL; 2730 bpf_jit_free(aux->func[i]); 2731 } 2732 if (aux->func_cnt) { 2733 kfree(aux->func); 2734 bpf_prog_unlock_free(aux->prog); 2735 } else { 2736 bpf_jit_free(aux->prog); 2737 } 2738 } 2739 2740 void bpf_prog_free(struct bpf_prog *fp) 2741 { 2742 struct bpf_prog_aux *aux = fp->aux; 2743 2744 if (aux->dst_prog) 2745 bpf_prog_put(aux->dst_prog); 2746 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2747 schedule_work(&aux->work); 2748 } 2749 EXPORT_SYMBOL_GPL(bpf_prog_free); 2750 2751 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 2752 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2753 2754 void bpf_user_rnd_init_once(void) 2755 { 2756 prandom_init_once(&bpf_user_rnd_state); 2757 } 2758 2759 BPF_CALL_0(bpf_user_rnd_u32) 2760 { 2761 /* Should someone ever have the rather unwise idea to use some 2762 * of the registers passed into this function, then note that 2763 * this function is called from native eBPF and classic-to-eBPF 2764 * transformations. Register assignments from both sides are 2765 * different, f.e. classic always sets fn(ctx, A, X) here. 2766 */ 2767 struct rnd_state *state; 2768 u32 res; 2769 2770 state = &get_cpu_var(bpf_user_rnd_state); 2771 res = prandom_u32_state(state); 2772 put_cpu_var(bpf_user_rnd_state); 2773 2774 return res; 2775 } 2776 2777 BPF_CALL_0(bpf_get_raw_cpu_id) 2778 { 2779 return raw_smp_processor_id(); 2780 } 2781 2782 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2783 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2784 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2785 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2786 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2787 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2788 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2789 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak; 2790 const struct bpf_func_proto bpf_spin_lock_proto __weak; 2791 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 2792 const struct bpf_func_proto bpf_jiffies64_proto __weak; 2793 2794 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2795 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2796 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2797 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2798 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 2799 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak; 2800 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak; 2801 2802 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2803 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2804 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2805 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2806 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 2807 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2808 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 2809 const struct bpf_func_proto bpf_snprintf_btf_proto __weak; 2810 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; 2811 const struct bpf_func_proto bpf_set_retval_proto __weak; 2812 const struct bpf_func_proto bpf_get_retval_proto __weak; 2813 2814 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2815 { 2816 return NULL; 2817 } 2818 2819 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void) 2820 { 2821 return NULL; 2822 } 2823 2824 u64 __weak 2825 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2826 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2827 { 2828 return -ENOTSUPP; 2829 } 2830 EXPORT_SYMBOL_GPL(bpf_event_output); 2831 2832 /* Always built-in helper functions. */ 2833 const struct bpf_func_proto bpf_tail_call_proto = { 2834 .func = NULL, 2835 .gpl_only = false, 2836 .ret_type = RET_VOID, 2837 .arg1_type = ARG_PTR_TO_CTX, 2838 .arg2_type = ARG_CONST_MAP_PTR, 2839 .arg3_type = ARG_ANYTHING, 2840 }; 2841 2842 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 2843 * It is encouraged to implement bpf_int_jit_compile() instead, so that 2844 * eBPF and implicitly also cBPF can get JITed! 2845 */ 2846 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 2847 { 2848 return prog; 2849 } 2850 2851 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 2852 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 2853 */ 2854 void __weak bpf_jit_compile(struct bpf_prog *prog) 2855 { 2856 } 2857 2858 bool __weak bpf_helper_changes_pkt_data(void *func) 2859 { 2860 return false; 2861 } 2862 2863 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 2864 * analysis code and wants explicit zero extension inserted by verifier. 2865 * Otherwise, return FALSE. 2866 * 2867 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if 2868 * you don't override this. JITs that don't want these extra insns can detect 2869 * them using insn_is_zext. 2870 */ 2871 bool __weak bpf_jit_needs_zext(void) 2872 { 2873 return false; 2874 } 2875 2876 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ 2877 bool __weak bpf_jit_supports_subprog_tailcalls(void) 2878 { 2879 return false; 2880 } 2881 2882 bool __weak bpf_jit_supports_kfunc_call(void) 2883 { 2884 return false; 2885 } 2886 2887 bool __weak bpf_jit_supports_far_kfunc_call(void) 2888 { 2889 return false; 2890 } 2891 2892 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 2893 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 2894 */ 2895 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 2896 int len) 2897 { 2898 return -EFAULT; 2899 } 2900 2901 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, 2902 void *addr1, void *addr2) 2903 { 2904 return -ENOTSUPP; 2905 } 2906 2907 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len) 2908 { 2909 return ERR_PTR(-ENOTSUPP); 2910 } 2911 2912 int __weak bpf_arch_text_invalidate(void *dst, size_t len) 2913 { 2914 return -ENOTSUPP; 2915 } 2916 2917 #ifdef CONFIG_BPF_SYSCALL 2918 static int __init bpf_global_ma_init(void) 2919 { 2920 int ret; 2921 2922 ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false); 2923 bpf_global_ma_set = !ret; 2924 return ret; 2925 } 2926 late_initcall(bpf_global_ma_init); 2927 #endif 2928 2929 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 2930 EXPORT_SYMBOL(bpf_stats_enabled_key); 2931 2932 /* All definitions of tracepoints related to BPF. */ 2933 #define CREATE_TRACE_POINTS 2934 #include <linux/bpf_trace.h> 2935 2936 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 2937 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 2938