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 IMM insn->imm 65 66 struct bpf_mem_alloc bpf_global_ma; 67 bool bpf_global_ma_set; 68 69 /* No hurry in this branch 70 * 71 * Exported for the bpf jit load helper. 72 */ 73 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 74 { 75 u8 *ptr = NULL; 76 77 if (k >= SKF_NET_OFF) { 78 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 79 } else if (k >= SKF_LL_OFF) { 80 if (unlikely(!skb_mac_header_was_set(skb))) 81 return NULL; 82 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 83 } 84 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 85 return ptr; 86 87 return NULL; 88 } 89 90 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags) 91 { 92 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 93 struct bpf_prog_aux *aux; 94 struct bpf_prog *fp; 95 96 size = round_up(size, PAGE_SIZE); 97 fp = __vmalloc(size, gfp_flags); 98 if (fp == NULL) 99 return NULL; 100 101 aux = kzalloc(sizeof(*aux), bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags)); 102 if (aux == NULL) { 103 vfree(fp); 104 return NULL; 105 } 106 fp->active = alloc_percpu_gfp(int, bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags)); 107 if (!fp->active) { 108 vfree(fp); 109 kfree(aux); 110 return NULL; 111 } 112 113 fp->pages = size / PAGE_SIZE; 114 fp->aux = aux; 115 fp->aux->prog = fp; 116 fp->jit_requested = ebpf_jit_enabled(); 117 fp->blinding_requested = bpf_jit_blinding_enabled(fp); 118 #ifdef CONFIG_CGROUP_BPF 119 aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID; 120 #endif 121 122 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); 123 mutex_init(&fp->aux->used_maps_mutex); 124 mutex_init(&fp->aux->dst_mutex); 125 126 return fp; 127 } 128 129 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 130 { 131 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 132 struct bpf_prog *prog; 133 int cpu; 134 135 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); 136 if (!prog) 137 return NULL; 138 139 prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); 140 if (!prog->stats) { 141 free_percpu(prog->active); 142 kfree(prog->aux); 143 vfree(prog); 144 return NULL; 145 } 146 147 for_each_possible_cpu(cpu) { 148 struct bpf_prog_stats *pstats; 149 150 pstats = per_cpu_ptr(prog->stats, cpu); 151 u64_stats_init(&pstats->syncp); 152 } 153 return prog; 154 } 155 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 156 157 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 158 { 159 if (!prog->aux->nr_linfo || !prog->jit_requested) 160 return 0; 161 162 prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo, 163 sizeof(*prog->aux->jited_linfo), 164 bpf_memcg_flags(GFP_KERNEL | __GFP_NOWARN)); 165 if (!prog->aux->jited_linfo) 166 return -ENOMEM; 167 168 return 0; 169 } 170 171 void bpf_prog_jit_attempt_done(struct bpf_prog *prog) 172 { 173 if (prog->aux->jited_linfo && 174 (!prog->jited || !prog->aux->jited_linfo[0])) { 175 kvfree(prog->aux->jited_linfo); 176 prog->aux->jited_linfo = NULL; 177 } 178 179 kfree(prog->aux->kfunc_tab); 180 prog->aux->kfunc_tab = NULL; 181 } 182 183 /* The jit engine is responsible to provide an array 184 * for insn_off to the jited_off mapping (insn_to_jit_off). 185 * 186 * The idx to this array is the insn_off. Hence, the insn_off 187 * here is relative to the prog itself instead of the main prog. 188 * This array has one entry for each xlated bpf insn. 189 * 190 * jited_off is the byte off to the end of the jited insn. 191 * 192 * Hence, with 193 * insn_start: 194 * The first bpf insn off of the prog. The insn off 195 * here is relative to the main prog. 196 * e.g. if prog is a subprog, insn_start > 0 197 * linfo_idx: 198 * The prog's idx to prog->aux->linfo and jited_linfo 199 * 200 * jited_linfo[linfo_idx] = prog->bpf_func 201 * 202 * For i > linfo_idx, 203 * 204 * jited_linfo[i] = prog->bpf_func + 205 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 206 */ 207 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 208 const u32 *insn_to_jit_off) 209 { 210 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 211 const struct bpf_line_info *linfo; 212 void **jited_linfo; 213 214 if (!prog->aux->jited_linfo) 215 /* Userspace did not provide linfo */ 216 return; 217 218 linfo_idx = prog->aux->linfo_idx; 219 linfo = &prog->aux->linfo[linfo_idx]; 220 insn_start = linfo[0].insn_off; 221 insn_end = insn_start + prog->len; 222 223 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 224 jited_linfo[0] = prog->bpf_func; 225 226 nr_linfo = prog->aux->nr_linfo - linfo_idx; 227 228 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 229 /* The verifier ensures that linfo[i].insn_off is 230 * strictly increasing 231 */ 232 jited_linfo[i] = prog->bpf_func + 233 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 234 } 235 236 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 237 gfp_t gfp_extra_flags) 238 { 239 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 240 struct bpf_prog *fp; 241 u32 pages; 242 243 size = round_up(size, PAGE_SIZE); 244 pages = size / PAGE_SIZE; 245 if (pages <= fp_old->pages) 246 return fp_old; 247 248 fp = __vmalloc(size, gfp_flags); 249 if (fp) { 250 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 251 fp->pages = pages; 252 fp->aux->prog = fp; 253 254 /* We keep fp->aux from fp_old around in the new 255 * reallocated structure. 256 */ 257 fp_old->aux = NULL; 258 fp_old->stats = NULL; 259 fp_old->active = NULL; 260 __bpf_prog_free(fp_old); 261 } 262 263 return fp; 264 } 265 266 void __bpf_prog_free(struct bpf_prog *fp) 267 { 268 if (fp->aux) { 269 mutex_destroy(&fp->aux->used_maps_mutex); 270 mutex_destroy(&fp->aux->dst_mutex); 271 kfree(fp->aux->poke_tab); 272 kfree(fp->aux); 273 } 274 free_percpu(fp->stats); 275 free_percpu(fp->active); 276 vfree(fp); 277 } 278 279 int bpf_prog_calc_tag(struct bpf_prog *fp) 280 { 281 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64); 282 u32 raw_size = bpf_prog_tag_scratch_size(fp); 283 u32 digest[SHA1_DIGEST_WORDS]; 284 u32 ws[SHA1_WORKSPACE_WORDS]; 285 u32 i, bsize, psize, blocks; 286 struct bpf_insn *dst; 287 bool was_ld_map; 288 u8 *raw, *todo; 289 __be32 *result; 290 __be64 *bits; 291 292 raw = vmalloc(raw_size); 293 if (!raw) 294 return -ENOMEM; 295 296 sha1_init(digest); 297 memset(ws, 0, sizeof(ws)); 298 299 /* We need to take out the map fd for the digest calculation 300 * since they are unstable from user space side. 301 */ 302 dst = (void *)raw; 303 for (i = 0, was_ld_map = false; i < fp->len; i++) { 304 dst[i] = fp->insnsi[i]; 305 if (!was_ld_map && 306 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 307 (dst[i].src_reg == BPF_PSEUDO_MAP_FD || 308 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { 309 was_ld_map = true; 310 dst[i].imm = 0; 311 } else if (was_ld_map && 312 dst[i].code == 0 && 313 dst[i].dst_reg == 0 && 314 dst[i].src_reg == 0 && 315 dst[i].off == 0) { 316 was_ld_map = false; 317 dst[i].imm = 0; 318 } else { 319 was_ld_map = false; 320 } 321 } 322 323 psize = bpf_prog_insn_size(fp); 324 memset(&raw[psize], 0, raw_size - psize); 325 raw[psize++] = 0x80; 326 327 bsize = round_up(psize, SHA1_BLOCK_SIZE); 328 blocks = bsize / SHA1_BLOCK_SIZE; 329 todo = raw; 330 if (bsize - psize >= sizeof(__be64)) { 331 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 332 } else { 333 bits = (__be64 *)(todo + bsize + bits_offset); 334 blocks++; 335 } 336 *bits = cpu_to_be64((psize - 1) << 3); 337 338 while (blocks--) { 339 sha1_transform(digest, todo, ws); 340 todo += SHA1_BLOCK_SIZE; 341 } 342 343 result = (__force __be32 *)digest; 344 for (i = 0; i < SHA1_DIGEST_WORDS; i++) 345 result[i] = cpu_to_be32(digest[i]); 346 memcpy(fp->tag, result, sizeof(fp->tag)); 347 348 vfree(raw); 349 return 0; 350 } 351 352 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, 353 s32 end_new, s32 curr, const bool probe_pass) 354 { 355 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 356 s32 delta = end_new - end_old; 357 s64 imm = insn->imm; 358 359 if (curr < pos && curr + imm + 1 >= end_old) 360 imm += delta; 361 else if (curr >= end_new && curr + imm + 1 < end_new) 362 imm -= delta; 363 if (imm < imm_min || imm > imm_max) 364 return -ERANGE; 365 if (!probe_pass) 366 insn->imm = imm; 367 return 0; 368 } 369 370 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, 371 s32 end_new, s32 curr, const bool probe_pass) 372 { 373 const s32 off_min = S16_MIN, off_max = S16_MAX; 374 s32 delta = end_new - end_old; 375 s32 off = insn->off; 376 377 if (curr < pos && curr + off + 1 >= end_old) 378 off += delta; 379 else if (curr >= end_new && curr + off + 1 < end_new) 380 off -= delta; 381 if (off < off_min || off > off_max) 382 return -ERANGE; 383 if (!probe_pass) 384 insn->off = off; 385 return 0; 386 } 387 388 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 389 s32 end_new, const bool probe_pass) 390 { 391 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); 392 struct bpf_insn *insn = prog->insnsi; 393 int ret = 0; 394 395 for (i = 0; i < insn_cnt; i++, insn++) { 396 u8 code; 397 398 /* In the probing pass we still operate on the original, 399 * unpatched image in order to check overflows before we 400 * do any other adjustments. Therefore skip the patchlet. 401 */ 402 if (probe_pass && i == pos) { 403 i = end_new; 404 insn = prog->insnsi + end_old; 405 } 406 if (bpf_pseudo_func(insn)) { 407 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 408 end_new, i, probe_pass); 409 if (ret) 410 return ret; 411 continue; 412 } 413 code = insn->code; 414 if ((BPF_CLASS(code) != BPF_JMP && 415 BPF_CLASS(code) != BPF_JMP32) || 416 BPF_OP(code) == BPF_EXIT) 417 continue; 418 /* Adjust offset of jmps if we cross patch boundaries. */ 419 if (BPF_OP(code) == BPF_CALL) { 420 if (insn->src_reg != BPF_PSEUDO_CALL) 421 continue; 422 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 423 end_new, i, probe_pass); 424 } else { 425 ret = bpf_adj_delta_to_off(insn, pos, end_old, 426 end_new, i, probe_pass); 427 } 428 if (ret) 429 break; 430 } 431 432 return ret; 433 } 434 435 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 436 { 437 struct bpf_line_info *linfo; 438 u32 i, nr_linfo; 439 440 nr_linfo = prog->aux->nr_linfo; 441 if (!nr_linfo || !delta) 442 return; 443 444 linfo = prog->aux->linfo; 445 446 for (i = 0; i < nr_linfo; i++) 447 if (off < linfo[i].insn_off) 448 break; 449 450 /* Push all off < linfo[i].insn_off by delta */ 451 for (; i < nr_linfo; i++) 452 linfo[i].insn_off += delta; 453 } 454 455 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 456 const struct bpf_insn *patch, u32 len) 457 { 458 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 459 const u32 cnt_max = S16_MAX; 460 struct bpf_prog *prog_adj; 461 int err; 462 463 /* Since our patchlet doesn't expand the image, we're done. */ 464 if (insn_delta == 0) { 465 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 466 return prog; 467 } 468 469 insn_adj_cnt = prog->len + insn_delta; 470 471 /* Reject anything that would potentially let the insn->off 472 * target overflow when we have excessive program expansions. 473 * We need to probe here before we do any reallocation where 474 * we afterwards may not fail anymore. 475 */ 476 if (insn_adj_cnt > cnt_max && 477 (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) 478 return ERR_PTR(err); 479 480 /* Several new instructions need to be inserted. Make room 481 * for them. Likely, there's no need for a new allocation as 482 * last page could have large enough tailroom. 483 */ 484 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 485 GFP_USER); 486 if (!prog_adj) 487 return ERR_PTR(-ENOMEM); 488 489 prog_adj->len = insn_adj_cnt; 490 491 /* Patching happens in 3 steps: 492 * 493 * 1) Move over tail of insnsi from next instruction onwards, 494 * so we can patch the single target insn with one or more 495 * new ones (patching is always from 1 to n insns, n > 0). 496 * 2) Inject new instructions at the target location. 497 * 3) Adjust branch offsets if necessary. 498 */ 499 insn_rest = insn_adj_cnt - off - len; 500 501 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 502 sizeof(*patch) * insn_rest); 503 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 504 505 /* We are guaranteed to not fail at this point, otherwise 506 * the ship has sailed to reverse to the original state. An 507 * overflow cannot happen at this point. 508 */ 509 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); 510 511 bpf_adj_linfo(prog_adj, off, insn_delta); 512 513 return prog_adj; 514 } 515 516 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) 517 { 518 /* Branch offsets can't overflow when program is shrinking, no need 519 * to call bpf_adj_branches(..., true) here 520 */ 521 memmove(prog->insnsi + off, prog->insnsi + off + cnt, 522 sizeof(struct bpf_insn) * (prog->len - off - cnt)); 523 prog->len -= cnt; 524 525 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); 526 } 527 528 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 529 { 530 int i; 531 532 for (i = 0; i < fp->aux->func_cnt; i++) 533 bpf_prog_kallsyms_del(fp->aux->func[i]); 534 } 535 536 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 537 { 538 bpf_prog_kallsyms_del_subprogs(fp); 539 bpf_prog_kallsyms_del(fp); 540 } 541 542 #ifdef CONFIG_BPF_JIT 543 /* All BPF JIT sysctl knobs here. */ 544 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 545 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 546 int bpf_jit_harden __read_mostly; 547 long bpf_jit_limit __read_mostly; 548 long bpf_jit_limit_max __read_mostly; 549 550 static void 551 bpf_prog_ksym_set_addr(struct bpf_prog *prog) 552 { 553 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 554 555 prog->aux->ksym.start = (unsigned long) prog->bpf_func; 556 prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len; 557 } 558 559 static void 560 bpf_prog_ksym_set_name(struct bpf_prog *prog) 561 { 562 char *sym = prog->aux->ksym.name; 563 const char *end = sym + KSYM_NAME_LEN; 564 const struct btf_type *type; 565 const char *func_name; 566 567 BUILD_BUG_ON(sizeof("bpf_prog_") + 568 sizeof(prog->tag) * 2 + 569 /* name has been null terminated. 570 * We should need +1 for the '_' preceding 571 * the name. However, the null character 572 * is double counted between the name and the 573 * sizeof("bpf_prog_") above, so we omit 574 * the +1 here. 575 */ 576 sizeof(prog->aux->name) > KSYM_NAME_LEN); 577 578 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 579 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 580 581 /* prog->aux->name will be ignored if full btf name is available */ 582 if (prog->aux->func_info_cnt) { 583 type = btf_type_by_id(prog->aux->btf, 584 prog->aux->func_info[prog->aux->func_idx].type_id); 585 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 586 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 587 return; 588 } 589 590 if (prog->aux->name[0]) 591 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 592 else 593 *sym = 0; 594 } 595 596 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) 597 { 598 return container_of(n, struct bpf_ksym, tnode)->start; 599 } 600 601 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 602 struct latch_tree_node *b) 603 { 604 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); 605 } 606 607 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 608 { 609 unsigned long val = (unsigned long)key; 610 const struct bpf_ksym *ksym; 611 612 ksym = container_of(n, struct bpf_ksym, tnode); 613 614 if (val < ksym->start) 615 return -1; 616 if (val >= ksym->end) 617 return 1; 618 619 return 0; 620 } 621 622 static const struct latch_tree_ops bpf_tree_ops = { 623 .less = bpf_tree_less, 624 .comp = bpf_tree_comp, 625 }; 626 627 static DEFINE_SPINLOCK(bpf_lock); 628 static LIST_HEAD(bpf_kallsyms); 629 static struct latch_tree_root bpf_tree __cacheline_aligned; 630 631 void bpf_ksym_add(struct bpf_ksym *ksym) 632 { 633 spin_lock_bh(&bpf_lock); 634 WARN_ON_ONCE(!list_empty(&ksym->lnode)); 635 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); 636 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 637 spin_unlock_bh(&bpf_lock); 638 } 639 640 static void __bpf_ksym_del(struct bpf_ksym *ksym) 641 { 642 if (list_empty(&ksym->lnode)) 643 return; 644 645 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 646 list_del_rcu(&ksym->lnode); 647 } 648 649 void bpf_ksym_del(struct bpf_ksym *ksym) 650 { 651 spin_lock_bh(&bpf_lock); 652 __bpf_ksym_del(ksym); 653 spin_unlock_bh(&bpf_lock); 654 } 655 656 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 657 { 658 return fp->jited && !bpf_prog_was_classic(fp); 659 } 660 661 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 662 { 663 if (!bpf_prog_kallsyms_candidate(fp) || 664 !bpf_capable()) 665 return; 666 667 bpf_prog_ksym_set_addr(fp); 668 bpf_prog_ksym_set_name(fp); 669 fp->aux->ksym.prog = true; 670 671 bpf_ksym_add(&fp->aux->ksym); 672 } 673 674 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 675 { 676 if (!bpf_prog_kallsyms_candidate(fp)) 677 return; 678 679 bpf_ksym_del(&fp->aux->ksym); 680 } 681 682 static struct bpf_ksym *bpf_ksym_find(unsigned long addr) 683 { 684 struct latch_tree_node *n; 685 686 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 687 return n ? container_of(n, struct bpf_ksym, tnode) : NULL; 688 } 689 690 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, 691 unsigned long *off, char *sym) 692 { 693 struct bpf_ksym *ksym; 694 char *ret = NULL; 695 696 rcu_read_lock(); 697 ksym = bpf_ksym_find(addr); 698 if (ksym) { 699 unsigned long symbol_start = ksym->start; 700 unsigned long symbol_end = ksym->end; 701 702 strncpy(sym, ksym->name, KSYM_NAME_LEN); 703 704 ret = sym; 705 if (size) 706 *size = symbol_end - symbol_start; 707 if (off) 708 *off = addr - symbol_start; 709 } 710 rcu_read_unlock(); 711 712 return ret; 713 } 714 715 bool is_bpf_text_address(unsigned long addr) 716 { 717 bool ret; 718 719 rcu_read_lock(); 720 ret = bpf_ksym_find(addr) != NULL; 721 rcu_read_unlock(); 722 723 return ret; 724 } 725 726 static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) 727 { 728 struct bpf_ksym *ksym = bpf_ksym_find(addr); 729 730 return ksym && ksym->prog ? 731 container_of(ksym, struct bpf_prog_aux, ksym)->prog : 732 NULL; 733 } 734 735 const struct exception_table_entry *search_bpf_extables(unsigned long addr) 736 { 737 const struct exception_table_entry *e = NULL; 738 struct bpf_prog *prog; 739 740 rcu_read_lock(); 741 prog = bpf_prog_ksym_find(addr); 742 if (!prog) 743 goto out; 744 if (!prog->aux->num_exentries) 745 goto out; 746 747 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); 748 out: 749 rcu_read_unlock(); 750 return e; 751 } 752 753 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 754 char *sym) 755 { 756 struct bpf_ksym *ksym; 757 unsigned int it = 0; 758 int ret = -ERANGE; 759 760 if (!bpf_jit_kallsyms_enabled()) 761 return ret; 762 763 rcu_read_lock(); 764 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { 765 if (it++ != symnum) 766 continue; 767 768 strncpy(sym, ksym->name, KSYM_NAME_LEN); 769 770 *value = ksym->start; 771 *type = BPF_SYM_ELF_TYPE; 772 773 ret = 0; 774 break; 775 } 776 rcu_read_unlock(); 777 778 return ret; 779 } 780 781 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, 782 struct bpf_jit_poke_descriptor *poke) 783 { 784 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; 785 static const u32 poke_tab_max = 1024; 786 u32 slot = prog->aux->size_poke_tab; 787 u32 size = slot + 1; 788 789 if (size > poke_tab_max) 790 return -ENOSPC; 791 if (poke->tailcall_target || poke->tailcall_target_stable || 792 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) 793 return -EINVAL; 794 795 switch (poke->reason) { 796 case BPF_POKE_REASON_TAIL_CALL: 797 if (!poke->tail_call.map) 798 return -EINVAL; 799 break; 800 default: 801 return -EINVAL; 802 } 803 804 tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL); 805 if (!tab) 806 return -ENOMEM; 807 808 memcpy(&tab[slot], poke, sizeof(*poke)); 809 prog->aux->size_poke_tab = size; 810 prog->aux->poke_tab = tab; 811 812 return slot; 813 } 814 815 /* 816 * BPF program pack allocator. 817 * 818 * Most BPF programs are pretty small. Allocating a hole page for each 819 * program is sometime a waste. Many small bpf program also adds pressure 820 * to instruction TLB. To solve this issue, we introduce a BPF program pack 821 * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86) 822 * to host BPF programs. 823 */ 824 #define BPF_PROG_CHUNK_SHIFT 6 825 #define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT) 826 #define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1)) 827 828 struct bpf_prog_pack { 829 struct list_head list; 830 void *ptr; 831 unsigned long bitmap[]; 832 }; 833 834 void bpf_jit_fill_hole_with_zero(void *area, unsigned int size) 835 { 836 memset(area, 0, size); 837 } 838 839 #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) 840 841 static DEFINE_MUTEX(pack_mutex); 842 static LIST_HEAD(pack_list); 843 844 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with 845 * CONFIG_MMU=n. Use PAGE_SIZE in these cases. 846 */ 847 #ifdef PMD_SIZE 848 #define BPF_PROG_PACK_SIZE (PMD_SIZE * num_possible_nodes()) 849 #else 850 #define BPF_PROG_PACK_SIZE PAGE_SIZE 851 #endif 852 853 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE) 854 855 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) 856 { 857 struct bpf_prog_pack *pack; 858 859 pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)), 860 GFP_KERNEL); 861 if (!pack) 862 return NULL; 863 pack->ptr = module_alloc(BPF_PROG_PACK_SIZE); 864 if (!pack->ptr) { 865 kfree(pack); 866 return NULL; 867 } 868 bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE); 869 bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE); 870 list_add_tail(&pack->list, &pack_list); 871 872 set_vm_flush_reset_perms(pack->ptr); 873 set_memory_rox((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); 874 return pack; 875 } 876 877 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) 878 { 879 unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); 880 struct bpf_prog_pack *pack; 881 unsigned long pos; 882 void *ptr = NULL; 883 884 mutex_lock(&pack_mutex); 885 if (size > BPF_PROG_PACK_SIZE) { 886 size = round_up(size, PAGE_SIZE); 887 ptr = module_alloc(size); 888 if (ptr) { 889 bpf_fill_ill_insns(ptr, size); 890 set_vm_flush_reset_perms(ptr); 891 set_memory_rox((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 >> 1, 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 = get_random_u32_below(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 = get_random_u32_below(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 int err; 1191 1192 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 1193 if (!*func_addr_fixed) { 1194 /* Place-holder address till the last pass has collected 1195 * all addresses for JITed subprograms in which case we 1196 * can pick them up from prog->aux. 1197 */ 1198 if (!extra_pass) 1199 addr = NULL; 1200 else if (prog->aux->func && 1201 off >= 0 && off < prog->aux->func_cnt) 1202 addr = (u8 *)prog->aux->func[off]->bpf_func; 1203 else 1204 return -EINVAL; 1205 } else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && 1206 bpf_jit_supports_far_kfunc_call()) { 1207 err = bpf_get_kfunc_addr(prog, insn->imm, insn->off, &addr); 1208 if (err) 1209 return err; 1210 } else { 1211 /* Address of a BPF helper call. Since part of the core 1212 * kernel, it's always at a fixed location. __bpf_call_base 1213 * and the helper with imm relative to it are both in core 1214 * kernel. 1215 */ 1216 addr = (u8 *)__bpf_call_base + imm; 1217 } 1218 1219 *func_addr = (unsigned long)addr; 1220 return 0; 1221 } 1222 1223 static int bpf_jit_blind_insn(const struct bpf_insn *from, 1224 const struct bpf_insn *aux, 1225 struct bpf_insn *to_buff, 1226 bool emit_zext) 1227 { 1228 struct bpf_insn *to = to_buff; 1229 u32 imm_rnd = get_random_u32(); 1230 s16 off; 1231 1232 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 1233 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 1234 1235 /* Constraints on AX register: 1236 * 1237 * AX register is inaccessible from user space. It is mapped in 1238 * all JITs, and used here for constant blinding rewrites. It is 1239 * typically "stateless" meaning its contents are only valid within 1240 * the executed instruction, but not across several instructions. 1241 * There are a few exceptions however which are further detailed 1242 * below. 1243 * 1244 * Constant blinding is only used by JITs, not in the interpreter. 1245 * The interpreter uses AX in some occasions as a local temporary 1246 * register e.g. in DIV or MOD instructions. 1247 * 1248 * In restricted circumstances, the verifier can also use the AX 1249 * register for rewrites as long as they do not interfere with 1250 * the above cases! 1251 */ 1252 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 1253 goto out; 1254 1255 if (from->imm == 0 && 1256 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 1257 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 1258 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 1259 goto out; 1260 } 1261 1262 switch (from->code) { 1263 case BPF_ALU | BPF_ADD | BPF_K: 1264 case BPF_ALU | BPF_SUB | BPF_K: 1265 case BPF_ALU | BPF_AND | BPF_K: 1266 case BPF_ALU | BPF_OR | BPF_K: 1267 case BPF_ALU | BPF_XOR | BPF_K: 1268 case BPF_ALU | BPF_MUL | BPF_K: 1269 case BPF_ALU | BPF_MOV | BPF_K: 1270 case BPF_ALU | BPF_DIV | BPF_K: 1271 case BPF_ALU | BPF_MOD | BPF_K: 1272 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1273 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1274 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 1275 break; 1276 1277 case BPF_ALU64 | BPF_ADD | BPF_K: 1278 case BPF_ALU64 | BPF_SUB | BPF_K: 1279 case BPF_ALU64 | BPF_AND | BPF_K: 1280 case BPF_ALU64 | BPF_OR | BPF_K: 1281 case BPF_ALU64 | BPF_XOR | BPF_K: 1282 case BPF_ALU64 | BPF_MUL | BPF_K: 1283 case BPF_ALU64 | BPF_MOV | BPF_K: 1284 case BPF_ALU64 | BPF_DIV | BPF_K: 1285 case BPF_ALU64 | BPF_MOD | BPF_K: 1286 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1287 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1288 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 1289 break; 1290 1291 case BPF_JMP | BPF_JEQ | BPF_K: 1292 case BPF_JMP | BPF_JNE | BPF_K: 1293 case BPF_JMP | BPF_JGT | BPF_K: 1294 case BPF_JMP | BPF_JLT | BPF_K: 1295 case BPF_JMP | BPF_JGE | BPF_K: 1296 case BPF_JMP | BPF_JLE | BPF_K: 1297 case BPF_JMP | BPF_JSGT | BPF_K: 1298 case BPF_JMP | BPF_JSLT | BPF_K: 1299 case BPF_JMP | BPF_JSGE | BPF_K: 1300 case BPF_JMP | BPF_JSLE | BPF_K: 1301 case BPF_JMP | BPF_JSET | BPF_K: 1302 /* Accommodate for extra offset in case of a backjump. */ 1303 off = from->off; 1304 if (off < 0) 1305 off -= 2; 1306 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1307 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1308 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1309 break; 1310 1311 case BPF_JMP32 | BPF_JEQ | BPF_K: 1312 case BPF_JMP32 | BPF_JNE | BPF_K: 1313 case BPF_JMP32 | BPF_JGT | BPF_K: 1314 case BPF_JMP32 | BPF_JLT | BPF_K: 1315 case BPF_JMP32 | BPF_JGE | BPF_K: 1316 case BPF_JMP32 | BPF_JLE | BPF_K: 1317 case BPF_JMP32 | BPF_JSGT | BPF_K: 1318 case BPF_JMP32 | BPF_JSLT | BPF_K: 1319 case BPF_JMP32 | BPF_JSGE | BPF_K: 1320 case BPF_JMP32 | BPF_JSLE | BPF_K: 1321 case BPF_JMP32 | BPF_JSET | BPF_K: 1322 /* Accommodate for extra offset in case of a backjump. */ 1323 off = from->off; 1324 if (off < 0) 1325 off -= 2; 1326 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1327 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1328 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1329 off); 1330 break; 1331 1332 case BPF_LD | BPF_IMM | BPF_DW: 1333 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1334 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1335 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1336 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1337 break; 1338 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1339 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1340 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1341 if (emit_zext) 1342 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1343 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1344 break; 1345 1346 case BPF_ST | BPF_MEM | BPF_DW: 1347 case BPF_ST | BPF_MEM | BPF_W: 1348 case BPF_ST | BPF_MEM | BPF_H: 1349 case BPF_ST | BPF_MEM | BPF_B: 1350 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1351 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1352 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1353 break; 1354 } 1355 out: 1356 return to - to_buff; 1357 } 1358 1359 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1360 gfp_t gfp_extra_flags) 1361 { 1362 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1363 struct bpf_prog *fp; 1364 1365 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1366 if (fp != NULL) { 1367 /* aux->prog still points to the fp_other one, so 1368 * when promoting the clone to the real program, 1369 * this still needs to be adapted. 1370 */ 1371 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1372 } 1373 1374 return fp; 1375 } 1376 1377 static void bpf_prog_clone_free(struct bpf_prog *fp) 1378 { 1379 /* aux was stolen by the other clone, so we cannot free 1380 * it from this path! It will be freed eventually by the 1381 * other program on release. 1382 * 1383 * At this point, we don't need a deferred release since 1384 * clone is guaranteed to not be locked. 1385 */ 1386 fp->aux = NULL; 1387 fp->stats = NULL; 1388 fp->active = NULL; 1389 __bpf_prog_free(fp); 1390 } 1391 1392 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1393 { 1394 /* We have to repoint aux->prog to self, as we don't 1395 * know whether fp here is the clone or the original. 1396 */ 1397 fp->aux->prog = fp; 1398 bpf_prog_clone_free(fp_other); 1399 } 1400 1401 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1402 { 1403 struct bpf_insn insn_buff[16], aux[2]; 1404 struct bpf_prog *clone, *tmp; 1405 int insn_delta, insn_cnt; 1406 struct bpf_insn *insn; 1407 int i, rewritten; 1408 1409 if (!prog->blinding_requested || prog->blinded) 1410 return prog; 1411 1412 clone = bpf_prog_clone_create(prog, GFP_USER); 1413 if (!clone) 1414 return ERR_PTR(-ENOMEM); 1415 1416 insn_cnt = clone->len; 1417 insn = clone->insnsi; 1418 1419 for (i = 0; i < insn_cnt; i++, insn++) { 1420 if (bpf_pseudo_func(insn)) { 1421 /* ld_imm64 with an address of bpf subprog is not 1422 * a user controlled constant. Don't randomize it, 1423 * since it will conflict with jit_subprogs() logic. 1424 */ 1425 insn++; 1426 i++; 1427 continue; 1428 } 1429 1430 /* We temporarily need to hold the original ld64 insn 1431 * so that we can still access the first part in the 1432 * second blinding run. 1433 */ 1434 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1435 insn[1].code == 0) 1436 memcpy(aux, insn, sizeof(aux)); 1437 1438 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1439 clone->aux->verifier_zext); 1440 if (!rewritten) 1441 continue; 1442 1443 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1444 if (IS_ERR(tmp)) { 1445 /* Patching may have repointed aux->prog during 1446 * realloc from the original one, so we need to 1447 * fix it up here on error. 1448 */ 1449 bpf_jit_prog_release_other(prog, clone); 1450 return tmp; 1451 } 1452 1453 clone = tmp; 1454 insn_delta = rewritten - 1; 1455 1456 /* Walk new program and skip insns we just inserted. */ 1457 insn = clone->insnsi + i + insn_delta; 1458 insn_cnt += insn_delta; 1459 i += insn_delta; 1460 } 1461 1462 clone->blinded = 1; 1463 return clone; 1464 } 1465 #endif /* CONFIG_BPF_JIT */ 1466 1467 /* Base function for offset calculation. Needs to go into .text section, 1468 * therefore keeping it non-static as well; will also be used by JITs 1469 * anyway later on, so do not let the compiler omit it. This also needs 1470 * to go into kallsyms for correlation from e.g. bpftool, so naming 1471 * must not change. 1472 */ 1473 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1474 { 1475 return 0; 1476 } 1477 EXPORT_SYMBOL_GPL(__bpf_call_base); 1478 1479 /* All UAPI available opcodes. */ 1480 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1481 /* 32 bit ALU operations. */ \ 1482 /* Register based. */ \ 1483 INSN_3(ALU, ADD, X), \ 1484 INSN_3(ALU, SUB, X), \ 1485 INSN_3(ALU, AND, X), \ 1486 INSN_3(ALU, OR, X), \ 1487 INSN_3(ALU, LSH, X), \ 1488 INSN_3(ALU, RSH, X), \ 1489 INSN_3(ALU, XOR, X), \ 1490 INSN_3(ALU, MUL, X), \ 1491 INSN_3(ALU, MOV, X), \ 1492 INSN_3(ALU, ARSH, X), \ 1493 INSN_3(ALU, DIV, X), \ 1494 INSN_3(ALU, MOD, X), \ 1495 INSN_2(ALU, NEG), \ 1496 INSN_3(ALU, END, TO_BE), \ 1497 INSN_3(ALU, END, TO_LE), \ 1498 /* Immediate based. */ \ 1499 INSN_3(ALU, ADD, K), \ 1500 INSN_3(ALU, SUB, K), \ 1501 INSN_3(ALU, AND, K), \ 1502 INSN_3(ALU, OR, K), \ 1503 INSN_3(ALU, LSH, K), \ 1504 INSN_3(ALU, RSH, K), \ 1505 INSN_3(ALU, XOR, K), \ 1506 INSN_3(ALU, MUL, K), \ 1507 INSN_3(ALU, MOV, K), \ 1508 INSN_3(ALU, ARSH, K), \ 1509 INSN_3(ALU, DIV, K), \ 1510 INSN_3(ALU, MOD, K), \ 1511 /* 64 bit ALU operations. */ \ 1512 /* Register based. */ \ 1513 INSN_3(ALU64, ADD, X), \ 1514 INSN_3(ALU64, SUB, X), \ 1515 INSN_3(ALU64, AND, X), \ 1516 INSN_3(ALU64, OR, X), \ 1517 INSN_3(ALU64, LSH, X), \ 1518 INSN_3(ALU64, RSH, X), \ 1519 INSN_3(ALU64, XOR, X), \ 1520 INSN_3(ALU64, MUL, X), \ 1521 INSN_3(ALU64, MOV, X), \ 1522 INSN_3(ALU64, ARSH, X), \ 1523 INSN_3(ALU64, DIV, X), \ 1524 INSN_3(ALU64, MOD, X), \ 1525 INSN_2(ALU64, NEG), \ 1526 /* Immediate based. */ \ 1527 INSN_3(ALU64, ADD, K), \ 1528 INSN_3(ALU64, SUB, K), \ 1529 INSN_3(ALU64, AND, K), \ 1530 INSN_3(ALU64, OR, K), \ 1531 INSN_3(ALU64, LSH, K), \ 1532 INSN_3(ALU64, RSH, K), \ 1533 INSN_3(ALU64, XOR, K), \ 1534 INSN_3(ALU64, MUL, K), \ 1535 INSN_3(ALU64, MOV, K), \ 1536 INSN_3(ALU64, ARSH, K), \ 1537 INSN_3(ALU64, DIV, K), \ 1538 INSN_3(ALU64, MOD, K), \ 1539 /* Call instruction. */ \ 1540 INSN_2(JMP, CALL), \ 1541 /* Exit instruction. */ \ 1542 INSN_2(JMP, EXIT), \ 1543 /* 32-bit Jump instructions. */ \ 1544 /* Register based. */ \ 1545 INSN_3(JMP32, JEQ, X), \ 1546 INSN_3(JMP32, JNE, X), \ 1547 INSN_3(JMP32, JGT, X), \ 1548 INSN_3(JMP32, JLT, X), \ 1549 INSN_3(JMP32, JGE, X), \ 1550 INSN_3(JMP32, JLE, X), \ 1551 INSN_3(JMP32, JSGT, X), \ 1552 INSN_3(JMP32, JSLT, X), \ 1553 INSN_3(JMP32, JSGE, X), \ 1554 INSN_3(JMP32, JSLE, X), \ 1555 INSN_3(JMP32, JSET, X), \ 1556 /* Immediate based. */ \ 1557 INSN_3(JMP32, JEQ, K), \ 1558 INSN_3(JMP32, JNE, K), \ 1559 INSN_3(JMP32, JGT, K), \ 1560 INSN_3(JMP32, JLT, K), \ 1561 INSN_3(JMP32, JGE, K), \ 1562 INSN_3(JMP32, JLE, K), \ 1563 INSN_3(JMP32, JSGT, K), \ 1564 INSN_3(JMP32, JSLT, K), \ 1565 INSN_3(JMP32, JSGE, K), \ 1566 INSN_3(JMP32, JSLE, K), \ 1567 INSN_3(JMP32, JSET, K), \ 1568 /* Jump instructions. */ \ 1569 /* Register based. */ \ 1570 INSN_3(JMP, JEQ, X), \ 1571 INSN_3(JMP, JNE, X), \ 1572 INSN_3(JMP, JGT, X), \ 1573 INSN_3(JMP, JLT, X), \ 1574 INSN_3(JMP, JGE, X), \ 1575 INSN_3(JMP, JLE, X), \ 1576 INSN_3(JMP, JSGT, X), \ 1577 INSN_3(JMP, JSLT, X), \ 1578 INSN_3(JMP, JSGE, X), \ 1579 INSN_3(JMP, JSLE, X), \ 1580 INSN_3(JMP, JSET, X), \ 1581 /* Immediate based. */ \ 1582 INSN_3(JMP, JEQ, K), \ 1583 INSN_3(JMP, JNE, K), \ 1584 INSN_3(JMP, JGT, K), \ 1585 INSN_3(JMP, JLT, K), \ 1586 INSN_3(JMP, JGE, K), \ 1587 INSN_3(JMP, JLE, K), \ 1588 INSN_3(JMP, JSGT, K), \ 1589 INSN_3(JMP, JSLT, K), \ 1590 INSN_3(JMP, JSGE, K), \ 1591 INSN_3(JMP, JSLE, K), \ 1592 INSN_3(JMP, JSET, K), \ 1593 INSN_2(JMP, JA), \ 1594 /* Store instructions. */ \ 1595 /* Register based. */ \ 1596 INSN_3(STX, MEM, B), \ 1597 INSN_3(STX, MEM, H), \ 1598 INSN_3(STX, MEM, W), \ 1599 INSN_3(STX, MEM, DW), \ 1600 INSN_3(STX, ATOMIC, W), \ 1601 INSN_3(STX, ATOMIC, DW), \ 1602 /* Immediate based. */ \ 1603 INSN_3(ST, MEM, B), \ 1604 INSN_3(ST, MEM, H), \ 1605 INSN_3(ST, MEM, W), \ 1606 INSN_3(ST, MEM, DW), \ 1607 /* Load instructions. */ \ 1608 /* Register based. */ \ 1609 INSN_3(LDX, MEM, B), \ 1610 INSN_3(LDX, MEM, H), \ 1611 INSN_3(LDX, MEM, W), \ 1612 INSN_3(LDX, MEM, DW), \ 1613 /* Immediate based. */ \ 1614 INSN_3(LD, IMM, DW) 1615 1616 bool bpf_opcode_in_insntable(u8 code) 1617 { 1618 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1619 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1620 static const bool public_insntable[256] = { 1621 [0 ... 255] = false, 1622 /* Now overwrite non-defaults ... */ 1623 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1624 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1625 [BPF_LD | BPF_ABS | BPF_B] = true, 1626 [BPF_LD | BPF_ABS | BPF_H] = true, 1627 [BPF_LD | BPF_ABS | BPF_W] = true, 1628 [BPF_LD | BPF_IND | BPF_B] = true, 1629 [BPF_LD | BPF_IND | BPF_H] = true, 1630 [BPF_LD | BPF_IND | BPF_W] = true, 1631 }; 1632 #undef BPF_INSN_3_TBL 1633 #undef BPF_INSN_2_TBL 1634 return public_insntable[code]; 1635 } 1636 1637 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1638 u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) 1639 { 1640 memset(dst, 0, size); 1641 return -EFAULT; 1642 } 1643 1644 /** 1645 * ___bpf_prog_run - run eBPF program on a given context 1646 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1647 * @insn: is the array of eBPF instructions 1648 * 1649 * Decode and execute eBPF instructions. 1650 * 1651 * Return: whatever value is in %BPF_R0 at program exit 1652 */ 1653 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) 1654 { 1655 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1656 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1657 static const void * const jumptable[256] __annotate_jump_table = { 1658 [0 ... 255] = &&default_label, 1659 /* Now overwrite non-defaults ... */ 1660 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1661 /* Non-UAPI available opcodes. */ 1662 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1663 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1664 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC, 1665 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1666 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1667 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1668 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1669 }; 1670 #undef BPF_INSN_3_LBL 1671 #undef BPF_INSN_2_LBL 1672 u32 tail_call_cnt = 0; 1673 1674 #define CONT ({ insn++; goto select_insn; }) 1675 #define CONT_JMP ({ insn++; goto select_insn; }) 1676 1677 select_insn: 1678 goto *jumptable[insn->code]; 1679 1680 /* Explicitly mask the register-based shift amounts with 63 or 31 1681 * to avoid undefined behavior. Normally this won't affect the 1682 * generated code, for example, in case of native 64 bit archs such 1683 * as x86-64 or arm64, the compiler is optimizing the AND away for 1684 * the interpreter. In case of JITs, each of the JIT backends compiles 1685 * the BPF shift operations to machine instructions which produce 1686 * implementation-defined results in such a case; the resulting 1687 * contents of the register may be arbitrary, but program behaviour 1688 * as a whole remains defined. In other words, in case of JIT backends, 1689 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation. 1690 */ 1691 /* ALU (shifts) */ 1692 #define SHT(OPCODE, OP) \ 1693 ALU64_##OPCODE##_X: \ 1694 DST = DST OP (SRC & 63); \ 1695 CONT; \ 1696 ALU_##OPCODE##_X: \ 1697 DST = (u32) DST OP ((u32) SRC & 31); \ 1698 CONT; \ 1699 ALU64_##OPCODE##_K: \ 1700 DST = DST OP IMM; \ 1701 CONT; \ 1702 ALU_##OPCODE##_K: \ 1703 DST = (u32) DST OP (u32) IMM; \ 1704 CONT; 1705 /* ALU (rest) */ 1706 #define ALU(OPCODE, OP) \ 1707 ALU64_##OPCODE##_X: \ 1708 DST = DST OP SRC; \ 1709 CONT; \ 1710 ALU_##OPCODE##_X: \ 1711 DST = (u32) DST OP (u32) SRC; \ 1712 CONT; \ 1713 ALU64_##OPCODE##_K: \ 1714 DST = DST OP IMM; \ 1715 CONT; \ 1716 ALU_##OPCODE##_K: \ 1717 DST = (u32) DST OP (u32) IMM; \ 1718 CONT; 1719 ALU(ADD, +) 1720 ALU(SUB, -) 1721 ALU(AND, &) 1722 ALU(OR, |) 1723 ALU(XOR, ^) 1724 ALU(MUL, *) 1725 SHT(LSH, <<) 1726 SHT(RSH, >>) 1727 #undef SHT 1728 #undef ALU 1729 ALU_NEG: 1730 DST = (u32) -DST; 1731 CONT; 1732 ALU64_NEG: 1733 DST = -DST; 1734 CONT; 1735 ALU_MOV_X: 1736 DST = (u32) SRC; 1737 CONT; 1738 ALU_MOV_K: 1739 DST = (u32) IMM; 1740 CONT; 1741 ALU64_MOV_X: 1742 DST = SRC; 1743 CONT; 1744 ALU64_MOV_K: 1745 DST = IMM; 1746 CONT; 1747 LD_IMM_DW: 1748 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1749 insn++; 1750 CONT; 1751 ALU_ARSH_X: 1752 DST = (u64) (u32) (((s32) DST) >> (SRC & 31)); 1753 CONT; 1754 ALU_ARSH_K: 1755 DST = (u64) (u32) (((s32) DST) >> IMM); 1756 CONT; 1757 ALU64_ARSH_X: 1758 (*(s64 *) &DST) >>= (SRC & 63); 1759 CONT; 1760 ALU64_ARSH_K: 1761 (*(s64 *) &DST) >>= IMM; 1762 CONT; 1763 ALU64_MOD_X: 1764 div64_u64_rem(DST, SRC, &AX); 1765 DST = AX; 1766 CONT; 1767 ALU_MOD_X: 1768 AX = (u32) DST; 1769 DST = do_div(AX, (u32) SRC); 1770 CONT; 1771 ALU64_MOD_K: 1772 div64_u64_rem(DST, IMM, &AX); 1773 DST = AX; 1774 CONT; 1775 ALU_MOD_K: 1776 AX = (u32) DST; 1777 DST = do_div(AX, (u32) IMM); 1778 CONT; 1779 ALU64_DIV_X: 1780 DST = div64_u64(DST, SRC); 1781 CONT; 1782 ALU_DIV_X: 1783 AX = (u32) DST; 1784 do_div(AX, (u32) SRC); 1785 DST = (u32) AX; 1786 CONT; 1787 ALU64_DIV_K: 1788 DST = div64_u64(DST, IMM); 1789 CONT; 1790 ALU_DIV_K: 1791 AX = (u32) DST; 1792 do_div(AX, (u32) IMM); 1793 DST = (u32) AX; 1794 CONT; 1795 ALU_END_TO_BE: 1796 switch (IMM) { 1797 case 16: 1798 DST = (__force u16) cpu_to_be16(DST); 1799 break; 1800 case 32: 1801 DST = (__force u32) cpu_to_be32(DST); 1802 break; 1803 case 64: 1804 DST = (__force u64) cpu_to_be64(DST); 1805 break; 1806 } 1807 CONT; 1808 ALU_END_TO_LE: 1809 switch (IMM) { 1810 case 16: 1811 DST = (__force u16) cpu_to_le16(DST); 1812 break; 1813 case 32: 1814 DST = (__force u32) cpu_to_le32(DST); 1815 break; 1816 case 64: 1817 DST = (__force u64) cpu_to_le64(DST); 1818 break; 1819 } 1820 CONT; 1821 1822 /* CALL */ 1823 JMP_CALL: 1824 /* Function call scratches BPF_R1-BPF_R5 registers, 1825 * preserves BPF_R6-BPF_R9, and stores return value 1826 * into BPF_R0. 1827 */ 1828 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1829 BPF_R4, BPF_R5); 1830 CONT; 1831 1832 JMP_CALL_ARGS: 1833 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 1834 BPF_R3, BPF_R4, 1835 BPF_R5, 1836 insn + insn->off + 1); 1837 CONT; 1838 1839 JMP_TAIL_CALL: { 1840 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1841 struct bpf_array *array = container_of(map, struct bpf_array, map); 1842 struct bpf_prog *prog; 1843 u32 index = BPF_R3; 1844 1845 if (unlikely(index >= array->map.max_entries)) 1846 goto out; 1847 1848 if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT)) 1849 goto out; 1850 1851 tail_call_cnt++; 1852 1853 prog = READ_ONCE(array->ptrs[index]); 1854 if (!prog) 1855 goto out; 1856 1857 /* ARG1 at this point is guaranteed to point to CTX from 1858 * the verifier side due to the fact that the tail call is 1859 * handled like a helper, that is, bpf_tail_call_proto, 1860 * where arg1_type is ARG_PTR_TO_CTX. 1861 */ 1862 insn = prog->insnsi; 1863 goto select_insn; 1864 out: 1865 CONT; 1866 } 1867 JMP_JA: 1868 insn += insn->off; 1869 CONT; 1870 JMP_EXIT: 1871 return BPF_R0; 1872 /* JMP */ 1873 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 1874 JMP_##OPCODE##_X: \ 1875 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 1876 insn += insn->off; \ 1877 CONT_JMP; \ 1878 } \ 1879 CONT; \ 1880 JMP32_##OPCODE##_X: \ 1881 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 1882 insn += insn->off; \ 1883 CONT_JMP; \ 1884 } \ 1885 CONT; \ 1886 JMP_##OPCODE##_K: \ 1887 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 1888 insn += insn->off; \ 1889 CONT_JMP; \ 1890 } \ 1891 CONT; \ 1892 JMP32_##OPCODE##_K: \ 1893 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 1894 insn += insn->off; \ 1895 CONT_JMP; \ 1896 } \ 1897 CONT; 1898 COND_JMP(u, JEQ, ==) 1899 COND_JMP(u, JNE, !=) 1900 COND_JMP(u, JGT, >) 1901 COND_JMP(u, JLT, <) 1902 COND_JMP(u, JGE, >=) 1903 COND_JMP(u, JLE, <=) 1904 COND_JMP(u, JSET, &) 1905 COND_JMP(s, JSGT, >) 1906 COND_JMP(s, JSLT, <) 1907 COND_JMP(s, JSGE, >=) 1908 COND_JMP(s, JSLE, <=) 1909 #undef COND_JMP 1910 /* ST, STX and LDX*/ 1911 ST_NOSPEC: 1912 /* Speculation barrier for mitigating Speculative Store Bypass. 1913 * In case of arm64, we rely on the firmware mitigation as 1914 * controlled via the ssbd kernel parameter. Whenever the 1915 * mitigation is enabled, it works for all of the kernel code 1916 * with no need to provide any additional instructions here. 1917 * In case of x86, we use 'lfence' insn for mitigation. We 1918 * reuse preexisting logic from Spectre v1 mitigation that 1919 * happens to produce the required code on x86 for v4 as well. 1920 */ 1921 barrier_nospec(); 1922 CONT; 1923 #define LDST(SIZEOP, SIZE) \ 1924 STX_MEM_##SIZEOP: \ 1925 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 1926 CONT; \ 1927 ST_MEM_##SIZEOP: \ 1928 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 1929 CONT; \ 1930 LDX_MEM_##SIZEOP: \ 1931 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 1932 CONT; \ 1933 LDX_PROBE_MEM_##SIZEOP: \ 1934 bpf_probe_read_kernel(&DST, sizeof(SIZE), \ 1935 (const void *)(long) (SRC + insn->off)); \ 1936 DST = *((SIZE *)&DST); \ 1937 CONT; 1938 1939 LDST(B, u8) 1940 LDST(H, u16) 1941 LDST(W, u32) 1942 LDST(DW, u64) 1943 #undef LDST 1944 1945 #define ATOMIC_ALU_OP(BOP, KOP) \ 1946 case BOP: \ 1947 if (BPF_SIZE(insn->code) == BPF_W) \ 1948 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \ 1949 (DST + insn->off)); \ 1950 else \ 1951 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \ 1952 (DST + insn->off)); \ 1953 break; \ 1954 case BOP | BPF_FETCH: \ 1955 if (BPF_SIZE(insn->code) == BPF_W) \ 1956 SRC = (u32) atomic_fetch_##KOP( \ 1957 (u32) SRC, \ 1958 (atomic_t *)(unsigned long) (DST + insn->off)); \ 1959 else \ 1960 SRC = (u64) atomic64_fetch_##KOP( \ 1961 (u64) SRC, \ 1962 (atomic64_t *)(unsigned long) (DST + insn->off)); \ 1963 break; 1964 1965 STX_ATOMIC_DW: 1966 STX_ATOMIC_W: 1967 switch (IMM) { 1968 ATOMIC_ALU_OP(BPF_ADD, add) 1969 ATOMIC_ALU_OP(BPF_AND, and) 1970 ATOMIC_ALU_OP(BPF_OR, or) 1971 ATOMIC_ALU_OP(BPF_XOR, xor) 1972 #undef ATOMIC_ALU_OP 1973 1974 case BPF_XCHG: 1975 if (BPF_SIZE(insn->code) == BPF_W) 1976 SRC = (u32) atomic_xchg( 1977 (atomic_t *)(unsigned long) (DST + insn->off), 1978 (u32) SRC); 1979 else 1980 SRC = (u64) atomic64_xchg( 1981 (atomic64_t *)(unsigned long) (DST + insn->off), 1982 (u64) SRC); 1983 break; 1984 case BPF_CMPXCHG: 1985 if (BPF_SIZE(insn->code) == BPF_W) 1986 BPF_R0 = (u32) atomic_cmpxchg( 1987 (atomic_t *)(unsigned long) (DST + insn->off), 1988 (u32) BPF_R0, (u32) SRC); 1989 else 1990 BPF_R0 = (u64) atomic64_cmpxchg( 1991 (atomic64_t *)(unsigned long) (DST + insn->off), 1992 (u64) BPF_R0, (u64) SRC); 1993 break; 1994 1995 default: 1996 goto default_label; 1997 } 1998 CONT; 1999 2000 default_label: 2001 /* If we ever reach this, we have a bug somewhere. Die hard here 2002 * instead of just returning 0; we could be somewhere in a subprog, 2003 * so execution could continue otherwise which we do /not/ want. 2004 * 2005 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 2006 */ 2007 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n", 2008 insn->code, insn->imm); 2009 BUG_ON(1); 2010 return 0; 2011 } 2012 2013 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 2014 #define DEFINE_BPF_PROG_RUN(stack_size) \ 2015 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 2016 { \ 2017 u64 stack[stack_size / sizeof(u64)]; \ 2018 u64 regs[MAX_BPF_EXT_REG] = {}; \ 2019 \ 2020 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2021 ARG1 = (u64) (unsigned long) ctx; \ 2022 return ___bpf_prog_run(regs, insn); \ 2023 } 2024 2025 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 2026 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 2027 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 2028 const struct bpf_insn *insn) \ 2029 { \ 2030 u64 stack[stack_size / sizeof(u64)]; \ 2031 u64 regs[MAX_BPF_EXT_REG]; \ 2032 \ 2033 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2034 BPF_R1 = r1; \ 2035 BPF_R2 = r2; \ 2036 BPF_R3 = r3; \ 2037 BPF_R4 = r4; \ 2038 BPF_R5 = r5; \ 2039 return ___bpf_prog_run(regs, insn); \ 2040 } 2041 2042 #define EVAL1(FN, X) FN(X) 2043 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 2044 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 2045 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 2046 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 2047 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 2048 2049 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 2050 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 2051 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 2052 2053 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 2054 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 2055 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 2056 2057 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 2058 2059 static unsigned int (*interpreters[])(const void *ctx, 2060 const struct bpf_insn *insn) = { 2061 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2062 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2063 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2064 }; 2065 #undef PROG_NAME_LIST 2066 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 2067 static __maybe_unused 2068 u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 2069 const struct bpf_insn *insn) = { 2070 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2071 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2072 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2073 }; 2074 #undef PROG_NAME_LIST 2075 2076 #ifdef CONFIG_BPF_SYSCALL 2077 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 2078 { 2079 stack_depth = max_t(u32, stack_depth, 1); 2080 insn->off = (s16) insn->imm; 2081 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 2082 __bpf_call_base_args; 2083 insn->code = BPF_JMP | BPF_CALL_ARGS; 2084 } 2085 #endif 2086 #else 2087 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 2088 const struct bpf_insn *insn) 2089 { 2090 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 2091 * is not working properly, so warn about it! 2092 */ 2093 WARN_ON_ONCE(1); 2094 return 0; 2095 } 2096 #endif 2097 2098 bool bpf_prog_map_compatible(struct bpf_map *map, 2099 const struct bpf_prog *fp) 2100 { 2101 enum bpf_prog_type prog_type = resolve_prog_type(fp); 2102 bool ret; 2103 2104 if (fp->kprobe_override) 2105 return false; 2106 2107 /* XDP programs inserted into maps are not guaranteed to run on 2108 * a particular netdev (and can run outside driver context entirely 2109 * in the case of devmap and cpumap). Until device checks 2110 * are implemented, prohibit adding dev-bound programs to program maps. 2111 */ 2112 if (bpf_prog_is_dev_bound(fp->aux)) 2113 return false; 2114 2115 spin_lock(&map->owner.lock); 2116 if (!map->owner.type) { 2117 /* There's no owner yet where we could check for 2118 * compatibility. 2119 */ 2120 map->owner.type = prog_type; 2121 map->owner.jited = fp->jited; 2122 map->owner.xdp_has_frags = fp->aux->xdp_has_frags; 2123 ret = true; 2124 } else { 2125 ret = map->owner.type == prog_type && 2126 map->owner.jited == fp->jited && 2127 map->owner.xdp_has_frags == fp->aux->xdp_has_frags; 2128 } 2129 spin_unlock(&map->owner.lock); 2130 2131 return ret; 2132 } 2133 2134 static int bpf_check_tail_call(const struct bpf_prog *fp) 2135 { 2136 struct bpf_prog_aux *aux = fp->aux; 2137 int i, ret = 0; 2138 2139 mutex_lock(&aux->used_maps_mutex); 2140 for (i = 0; i < aux->used_map_cnt; i++) { 2141 struct bpf_map *map = aux->used_maps[i]; 2142 2143 if (!map_type_contains_progs(map)) 2144 continue; 2145 2146 if (!bpf_prog_map_compatible(map, fp)) { 2147 ret = -EINVAL; 2148 goto out; 2149 } 2150 } 2151 2152 out: 2153 mutex_unlock(&aux->used_maps_mutex); 2154 return ret; 2155 } 2156 2157 static void bpf_prog_select_func(struct bpf_prog *fp) 2158 { 2159 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 2160 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 2161 2162 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 2163 #else 2164 fp->bpf_func = __bpf_prog_ret0_warn; 2165 #endif 2166 } 2167 2168 /** 2169 * bpf_prog_select_runtime - select exec runtime for BPF program 2170 * @fp: bpf_prog populated with BPF program 2171 * @err: pointer to error variable 2172 * 2173 * Try to JIT eBPF program, if JIT is not available, use interpreter. 2174 * The BPF program will be executed via bpf_prog_run() function. 2175 * 2176 * Return: the &fp argument along with &err set to 0 for success or 2177 * a negative errno code on failure 2178 */ 2179 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 2180 { 2181 /* In case of BPF to BPF calls, verifier did all the prep 2182 * work with regards to JITing, etc. 2183 */ 2184 bool jit_needed = false; 2185 2186 if (fp->bpf_func) 2187 goto finalize; 2188 2189 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || 2190 bpf_prog_has_kfunc_call(fp)) 2191 jit_needed = true; 2192 2193 bpf_prog_select_func(fp); 2194 2195 /* eBPF JITs can rewrite the program in case constant 2196 * blinding is active. However, in case of error during 2197 * blinding, bpf_int_jit_compile() must always return a 2198 * valid program, which in this case would simply not 2199 * be JITed, but falls back to the interpreter. 2200 */ 2201 if (!bpf_prog_is_offloaded(fp->aux)) { 2202 *err = bpf_prog_alloc_jited_linfo(fp); 2203 if (*err) 2204 return fp; 2205 2206 fp = bpf_int_jit_compile(fp); 2207 bpf_prog_jit_attempt_done(fp); 2208 if (!fp->jited && jit_needed) { 2209 *err = -ENOTSUPP; 2210 return fp; 2211 } 2212 } else { 2213 *err = bpf_prog_offload_compile(fp); 2214 if (*err) 2215 return fp; 2216 } 2217 2218 finalize: 2219 bpf_prog_lock_ro(fp); 2220 2221 /* The tail call compatibility check can only be done at 2222 * this late stage as we need to determine, if we deal 2223 * with JITed or non JITed program concatenations and not 2224 * all eBPF JITs might immediately support all features. 2225 */ 2226 *err = bpf_check_tail_call(fp); 2227 2228 return fp; 2229 } 2230 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 2231 2232 static unsigned int __bpf_prog_ret1(const void *ctx, 2233 const struct bpf_insn *insn) 2234 { 2235 return 1; 2236 } 2237 2238 static struct bpf_prog_dummy { 2239 struct bpf_prog prog; 2240 } dummy_bpf_prog = { 2241 .prog = { 2242 .bpf_func = __bpf_prog_ret1, 2243 }, 2244 }; 2245 2246 struct bpf_empty_prog_array bpf_empty_prog_array = { 2247 .null_prog = NULL, 2248 }; 2249 EXPORT_SYMBOL(bpf_empty_prog_array); 2250 2251 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 2252 { 2253 if (prog_cnt) 2254 return kzalloc(sizeof(struct bpf_prog_array) + 2255 sizeof(struct bpf_prog_array_item) * 2256 (prog_cnt + 1), 2257 flags); 2258 2259 return &bpf_empty_prog_array.hdr; 2260 } 2261 2262 void bpf_prog_array_free(struct bpf_prog_array *progs) 2263 { 2264 if (!progs || progs == &bpf_empty_prog_array.hdr) 2265 return; 2266 kfree_rcu(progs, rcu); 2267 } 2268 2269 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu) 2270 { 2271 struct bpf_prog_array *progs; 2272 2273 /* If RCU Tasks Trace grace period implies RCU grace period, there is 2274 * no need to call kfree_rcu(), just call kfree() directly. 2275 */ 2276 progs = container_of(rcu, struct bpf_prog_array, rcu); 2277 if (rcu_trace_implies_rcu_gp()) 2278 kfree(progs); 2279 else 2280 kfree_rcu(progs, rcu); 2281 } 2282 2283 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs) 2284 { 2285 if (!progs || progs == &bpf_empty_prog_array.hdr) 2286 return; 2287 call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb); 2288 } 2289 2290 int bpf_prog_array_length(struct bpf_prog_array *array) 2291 { 2292 struct bpf_prog_array_item *item; 2293 u32 cnt = 0; 2294 2295 for (item = array->items; item->prog; item++) 2296 if (item->prog != &dummy_bpf_prog.prog) 2297 cnt++; 2298 return cnt; 2299 } 2300 2301 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 2302 { 2303 struct bpf_prog_array_item *item; 2304 2305 for (item = array->items; item->prog; item++) 2306 if (item->prog != &dummy_bpf_prog.prog) 2307 return false; 2308 return true; 2309 } 2310 2311 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 2312 u32 *prog_ids, 2313 u32 request_cnt) 2314 { 2315 struct bpf_prog_array_item *item; 2316 int i = 0; 2317 2318 for (item = array->items; item->prog; item++) { 2319 if (item->prog == &dummy_bpf_prog.prog) 2320 continue; 2321 prog_ids[i] = item->prog->aux->id; 2322 if (++i == request_cnt) { 2323 item++; 2324 break; 2325 } 2326 } 2327 2328 return !!(item->prog); 2329 } 2330 2331 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 2332 __u32 __user *prog_ids, u32 cnt) 2333 { 2334 unsigned long err = 0; 2335 bool nospc; 2336 u32 *ids; 2337 2338 /* users of this function are doing: 2339 * cnt = bpf_prog_array_length(); 2340 * if (cnt > 0) 2341 * bpf_prog_array_copy_to_user(..., cnt); 2342 * so below kcalloc doesn't need extra cnt > 0 check. 2343 */ 2344 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 2345 if (!ids) 2346 return -ENOMEM; 2347 nospc = bpf_prog_array_copy_core(array, ids, cnt); 2348 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 2349 kfree(ids); 2350 if (err) 2351 return -EFAULT; 2352 if (nospc) 2353 return -ENOSPC; 2354 return 0; 2355 } 2356 2357 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 2358 struct bpf_prog *old_prog) 2359 { 2360 struct bpf_prog_array_item *item; 2361 2362 for (item = array->items; item->prog; item++) 2363 if (item->prog == old_prog) { 2364 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 2365 break; 2366 } 2367 } 2368 2369 /** 2370 * bpf_prog_array_delete_safe_at() - Replaces the program at the given 2371 * index into the program array with 2372 * a dummy no-op program. 2373 * @array: a bpf_prog_array 2374 * @index: the index of the program to replace 2375 * 2376 * Skips over dummy programs, by not counting them, when calculating 2377 * the position of the program to replace. 2378 * 2379 * Return: 2380 * * 0 - Success 2381 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2382 * * -ENOENT - Index out of range 2383 */ 2384 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) 2385 { 2386 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); 2387 } 2388 2389 /** 2390 * bpf_prog_array_update_at() - Updates the program at the given index 2391 * into the program array. 2392 * @array: a bpf_prog_array 2393 * @index: the index of the program to update 2394 * @prog: the program to insert into the array 2395 * 2396 * Skips over dummy programs, by not counting them, when calculating 2397 * the position of the program to update. 2398 * 2399 * Return: 2400 * * 0 - Success 2401 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2402 * * -ENOENT - Index out of range 2403 */ 2404 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, 2405 struct bpf_prog *prog) 2406 { 2407 struct bpf_prog_array_item *item; 2408 2409 if (unlikely(index < 0)) 2410 return -EINVAL; 2411 2412 for (item = array->items; item->prog; item++) { 2413 if (item->prog == &dummy_bpf_prog.prog) 2414 continue; 2415 if (!index) { 2416 WRITE_ONCE(item->prog, prog); 2417 return 0; 2418 } 2419 index--; 2420 } 2421 return -ENOENT; 2422 } 2423 2424 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 2425 struct bpf_prog *exclude_prog, 2426 struct bpf_prog *include_prog, 2427 u64 bpf_cookie, 2428 struct bpf_prog_array **new_array) 2429 { 2430 int new_prog_cnt, carry_prog_cnt = 0; 2431 struct bpf_prog_array_item *existing, *new; 2432 struct bpf_prog_array *array; 2433 bool found_exclude = false; 2434 2435 /* Figure out how many existing progs we need to carry over to 2436 * the new array. 2437 */ 2438 if (old_array) { 2439 existing = old_array->items; 2440 for (; existing->prog; existing++) { 2441 if (existing->prog == exclude_prog) { 2442 found_exclude = true; 2443 continue; 2444 } 2445 if (existing->prog != &dummy_bpf_prog.prog) 2446 carry_prog_cnt++; 2447 if (existing->prog == include_prog) 2448 return -EEXIST; 2449 } 2450 } 2451 2452 if (exclude_prog && !found_exclude) 2453 return -ENOENT; 2454 2455 /* How many progs (not NULL) will be in the new array? */ 2456 new_prog_cnt = carry_prog_cnt; 2457 if (include_prog) 2458 new_prog_cnt += 1; 2459 2460 /* Do we have any prog (not NULL) in the new array? */ 2461 if (!new_prog_cnt) { 2462 *new_array = NULL; 2463 return 0; 2464 } 2465 2466 /* +1 as the end of prog_array is marked with NULL */ 2467 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2468 if (!array) 2469 return -ENOMEM; 2470 new = array->items; 2471 2472 /* Fill in the new prog array */ 2473 if (carry_prog_cnt) { 2474 existing = old_array->items; 2475 for (; existing->prog; existing++) { 2476 if (existing->prog == exclude_prog || 2477 existing->prog == &dummy_bpf_prog.prog) 2478 continue; 2479 2480 new->prog = existing->prog; 2481 new->bpf_cookie = existing->bpf_cookie; 2482 new++; 2483 } 2484 } 2485 if (include_prog) { 2486 new->prog = include_prog; 2487 new->bpf_cookie = bpf_cookie; 2488 new++; 2489 } 2490 new->prog = NULL; 2491 *new_array = array; 2492 return 0; 2493 } 2494 2495 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2496 u32 *prog_ids, u32 request_cnt, 2497 u32 *prog_cnt) 2498 { 2499 u32 cnt = 0; 2500 2501 if (array) 2502 cnt = bpf_prog_array_length(array); 2503 2504 *prog_cnt = cnt; 2505 2506 /* return early if user requested only program count or nothing to copy */ 2507 if (!request_cnt || !cnt) 2508 return 0; 2509 2510 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2511 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2512 : 0; 2513 } 2514 2515 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2516 struct bpf_map **used_maps, u32 len) 2517 { 2518 struct bpf_map *map; 2519 u32 i; 2520 2521 for (i = 0; i < len; i++) { 2522 map = used_maps[i]; 2523 if (map->ops->map_poke_untrack) 2524 map->ops->map_poke_untrack(map, aux); 2525 bpf_map_put(map); 2526 } 2527 } 2528 2529 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2530 { 2531 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2532 kfree(aux->used_maps); 2533 } 2534 2535 void __bpf_free_used_btfs(struct bpf_prog_aux *aux, 2536 struct btf_mod_pair *used_btfs, u32 len) 2537 { 2538 #ifdef CONFIG_BPF_SYSCALL 2539 struct btf_mod_pair *btf_mod; 2540 u32 i; 2541 2542 for (i = 0; i < len; i++) { 2543 btf_mod = &used_btfs[i]; 2544 if (btf_mod->module) 2545 module_put(btf_mod->module); 2546 btf_put(btf_mod->btf); 2547 } 2548 #endif 2549 } 2550 2551 static void bpf_free_used_btfs(struct bpf_prog_aux *aux) 2552 { 2553 __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt); 2554 kfree(aux->used_btfs); 2555 } 2556 2557 static void bpf_prog_free_deferred(struct work_struct *work) 2558 { 2559 struct bpf_prog_aux *aux; 2560 int i; 2561 2562 aux = container_of(work, struct bpf_prog_aux, work); 2563 #ifdef CONFIG_BPF_SYSCALL 2564 bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab); 2565 #endif 2566 #ifdef CONFIG_CGROUP_BPF 2567 if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID) 2568 bpf_cgroup_atype_put(aux->cgroup_atype); 2569 #endif 2570 bpf_free_used_maps(aux); 2571 bpf_free_used_btfs(aux); 2572 if (bpf_prog_is_dev_bound(aux)) 2573 bpf_prog_dev_bound_destroy(aux->prog); 2574 #ifdef CONFIG_PERF_EVENTS 2575 if (aux->prog->has_callchain_buf) 2576 put_callchain_buffers(); 2577 #endif 2578 if (aux->dst_trampoline) 2579 bpf_trampoline_put(aux->dst_trampoline); 2580 for (i = 0; i < aux->func_cnt; i++) { 2581 /* We can just unlink the subprog poke descriptor table as 2582 * it was originally linked to the main program and is also 2583 * released along with it. 2584 */ 2585 aux->func[i]->aux->poke_tab = NULL; 2586 bpf_jit_free(aux->func[i]); 2587 } 2588 if (aux->func_cnt) { 2589 kfree(aux->func); 2590 bpf_prog_unlock_free(aux->prog); 2591 } else { 2592 bpf_jit_free(aux->prog); 2593 } 2594 } 2595 2596 void bpf_prog_free(struct bpf_prog *fp) 2597 { 2598 struct bpf_prog_aux *aux = fp->aux; 2599 2600 if (aux->dst_prog) 2601 bpf_prog_put(aux->dst_prog); 2602 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2603 schedule_work(&aux->work); 2604 } 2605 EXPORT_SYMBOL_GPL(bpf_prog_free); 2606 2607 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 2608 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2609 2610 void bpf_user_rnd_init_once(void) 2611 { 2612 prandom_init_once(&bpf_user_rnd_state); 2613 } 2614 2615 BPF_CALL_0(bpf_user_rnd_u32) 2616 { 2617 /* Should someone ever have the rather unwise idea to use some 2618 * of the registers passed into this function, then note that 2619 * this function is called from native eBPF and classic-to-eBPF 2620 * transformations. Register assignments from both sides are 2621 * different, f.e. classic always sets fn(ctx, A, X) here. 2622 */ 2623 struct rnd_state *state; 2624 u32 res; 2625 2626 state = &get_cpu_var(bpf_user_rnd_state); 2627 res = prandom_u32_state(state); 2628 put_cpu_var(bpf_user_rnd_state); 2629 2630 return res; 2631 } 2632 2633 BPF_CALL_0(bpf_get_raw_cpu_id) 2634 { 2635 return raw_smp_processor_id(); 2636 } 2637 2638 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2639 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2640 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2641 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2642 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2643 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2644 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2645 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak; 2646 const struct bpf_func_proto bpf_spin_lock_proto __weak; 2647 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 2648 const struct bpf_func_proto bpf_jiffies64_proto __weak; 2649 2650 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2651 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2652 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2653 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2654 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 2655 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak; 2656 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak; 2657 2658 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2659 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2660 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2661 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2662 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 2663 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2664 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 2665 const struct bpf_func_proto bpf_snprintf_btf_proto __weak; 2666 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; 2667 const struct bpf_func_proto bpf_set_retval_proto __weak; 2668 const struct bpf_func_proto bpf_get_retval_proto __weak; 2669 2670 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2671 { 2672 return NULL; 2673 } 2674 2675 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void) 2676 { 2677 return NULL; 2678 } 2679 2680 u64 __weak 2681 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2682 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2683 { 2684 return -ENOTSUPP; 2685 } 2686 EXPORT_SYMBOL_GPL(bpf_event_output); 2687 2688 /* Always built-in helper functions. */ 2689 const struct bpf_func_proto bpf_tail_call_proto = { 2690 .func = NULL, 2691 .gpl_only = false, 2692 .ret_type = RET_VOID, 2693 .arg1_type = ARG_PTR_TO_CTX, 2694 .arg2_type = ARG_CONST_MAP_PTR, 2695 .arg3_type = ARG_ANYTHING, 2696 }; 2697 2698 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 2699 * It is encouraged to implement bpf_int_jit_compile() instead, so that 2700 * eBPF and implicitly also cBPF can get JITed! 2701 */ 2702 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 2703 { 2704 return prog; 2705 } 2706 2707 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 2708 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 2709 */ 2710 void __weak bpf_jit_compile(struct bpf_prog *prog) 2711 { 2712 } 2713 2714 bool __weak bpf_helper_changes_pkt_data(void *func) 2715 { 2716 return false; 2717 } 2718 2719 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 2720 * analysis code and wants explicit zero extension inserted by verifier. 2721 * Otherwise, return FALSE. 2722 * 2723 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if 2724 * you don't override this. JITs that don't want these extra insns can detect 2725 * them using insn_is_zext. 2726 */ 2727 bool __weak bpf_jit_needs_zext(void) 2728 { 2729 return false; 2730 } 2731 2732 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ 2733 bool __weak bpf_jit_supports_subprog_tailcalls(void) 2734 { 2735 return false; 2736 } 2737 2738 bool __weak bpf_jit_supports_kfunc_call(void) 2739 { 2740 return false; 2741 } 2742 2743 bool __weak bpf_jit_supports_far_kfunc_call(void) 2744 { 2745 return false; 2746 } 2747 2748 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 2749 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 2750 */ 2751 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 2752 int len) 2753 { 2754 return -EFAULT; 2755 } 2756 2757 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, 2758 void *addr1, void *addr2) 2759 { 2760 return -ENOTSUPP; 2761 } 2762 2763 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len) 2764 { 2765 return ERR_PTR(-ENOTSUPP); 2766 } 2767 2768 int __weak bpf_arch_text_invalidate(void *dst, size_t len) 2769 { 2770 return -ENOTSUPP; 2771 } 2772 2773 #ifdef CONFIG_BPF_SYSCALL 2774 static int __init bpf_global_ma_init(void) 2775 { 2776 int ret; 2777 2778 ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false); 2779 bpf_global_ma_set = !ret; 2780 return ret; 2781 } 2782 late_initcall(bpf_global_ma_init); 2783 #endif 2784 2785 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 2786 EXPORT_SYMBOL(bpf_stats_enabled_key); 2787 2788 /* All definitions of tracepoints related to BPF. */ 2789 #define CREATE_TRACE_POINTS 2790 #include <linux/bpf_trace.h> 2791 2792 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 2793 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 2794