kernel/bpf/core.c

   1 /*
   2  * Linux Socket Filter - Kernel level socket filtering
   3  *
   4  * Based on the design of the Berkeley Packet Filter. The new
   5  * internal format has been designed by PLUMgrid:
   6  *
   7  *      Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
   8  *
   9  * Authors:
  10  *
  11  *      Jay Schulist <[email protected]>
  12  *      Alexei Starovoitov <[email protected]>
  13  *      Daniel Borkmann <[email protected]>
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version
  18  * 2 of the License, or (at your option) any later version.
  19  *
  20  * Andi Kleen - Fix a few bad bugs and races.
  21  * Kris Katterjohn - Added many additional checks in bpf_check_classic()
  22  */
  23
  24 #include <linux/filter.h>
  25 #include <linux/skbuff.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/random.h>
  28 #include <linux/moduleloader.h>
  29 #include <linux/bpf.h>
  30 #include <linux/frame.h>
  31 #include <linux/rbtree_latch.h>
  32 #include <linux/kallsyms.h>
  33 #include <linux/rcupdate.h>
  34
  35 #include <asm/unaligned.h>
  36
  37 /* Registers */
  38 #define BPF_R0  regs[BPF_REG_0]
  39 #define BPF_R1  regs[BPF_REG_1]
  40 #define BPF_R2  regs[BPF_REG_2]
  41 #define BPF_R3  regs[BPF_REG_3]
  42 #define BPF_R4  regs[BPF_REG_4]
  43 #define BPF_R5  regs[BPF_REG_5]
  44 #define BPF_R6  regs[BPF_REG_6]
  45 #define BPF_R7  regs[BPF_REG_7]
  46 #define BPF_R8  regs[BPF_REG_8]
  47 #define BPF_R9  regs[BPF_REG_9]
  48 #define BPF_R10 regs[BPF_REG_10]
  49
  50 /* Named registers */
  51 #define DST     regs[insn->dst_reg]
  52 #define SRC     regs[insn->src_reg]
  53 #define FP      regs[BPF_REG_FP]
  54 #define ARG1    regs[BPF_REG_ARG1]
  55 #define CTX     regs[BPF_REG_CTX]
  56 #define IMM     insn->imm
  57
  58 /* No hurry in this branch
  59  *
  60  * Exported for the bpf jit load helper.
  61  */
  62 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
  63 {
  64         u8 *ptr = NULL;
  65
  66         if (k >= SKF_NET_OFF)
  67                 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
  68         else if (k >= SKF_LL_OFF)
  69                 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
  70
  71         if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
  72                 return ptr;
  73
  74         return NULL;
  75 }
  76
  77 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
  78 {
  79         gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
  80         struct bpf_prog_aux *aux;
  81         struct bpf_prog *fp;
  82
  83         size = round_up(size, PAGE_SIZE);
  84         fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
  85         if (fp == NULL)
  86                 return NULL;
  87
  88         kmemcheck_annotate_bitfield(fp, meta);
  89
  90         aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
  91         if (aux == NULL) {
  92                 vfree(fp);
  93                 return NULL;
  94         }
  95
  96         fp->pages = size / PAGE_SIZE;
  97         fp->aux = aux;
  98         fp->aux->prog = fp;
  99
 100         INIT_LIST_HEAD_RCU(&fp->aux->ksym_lnode);
 101
 102         return fp;
 103 }
 104 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
 105
 106 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 107                                   gfp_t gfp_extra_flags)
 108 {
 109         gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
 110         struct bpf_prog *fp;
 111         u32 pages, delta;
 112         int ret;
 113
 114         BUG_ON(fp_old == NULL);
 115
 116         size = round_up(size, PAGE_SIZE);
 117         pages = size / PAGE_SIZE;
 118         if (pages <= fp_old->pages)
 119                 return fp_old;
 120
 121         delta = pages - fp_old->pages;
 122         ret = __bpf_prog_charge(fp_old->aux->user, delta);
 123         if (ret)
 124                 return NULL;
 125
 126         fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
 127         if (fp == NULL) {
 128                 __bpf_prog_uncharge(fp_old->aux->user, delta);
 129         } else {
 130                 kmemcheck_annotate_bitfield(fp, meta);
 131
 132                 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
 133                 fp->pages = pages;
 134                 fp->aux->prog = fp;
 135
 136                 /* We keep fp->aux from fp_old around in the new
 137                  * reallocated structure.
 138                  */
 139                 fp_old->aux = NULL;
 140                 __bpf_prog_free(fp_old);
 141         }
 142
 143         return fp;
 144 }
 145
 146 void __bpf_prog_free(struct bpf_prog *fp)
 147 {
 148         kfree(fp->aux);
 149         vfree(fp);
 150 }
 151
 152 int bpf_prog_calc_tag(struct bpf_prog *fp)
 153 {
 154         const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64);
 155         u32 raw_size = bpf_prog_tag_scratch_size(fp);
 156         u32 digest[SHA_DIGEST_WORDS];
 157         u32 ws[SHA_WORKSPACE_WORDS];
 158         u32 i, bsize, psize, blocks;
 159         struct bpf_insn *dst;
 160         bool was_ld_map;
 161         u8 *raw, *todo;
 162         __be32 *result;
 163         __be64 *bits;
 164
 165         raw = vmalloc(raw_size);
 166         if (!raw)
 167                 return -ENOMEM;
 168
 169         sha_init(digest);
 170         memset(ws, 0, sizeof(ws));
 171
 172         /* We need to take out the map fd for the digest calculation
 173          * since they are unstable from user space side.
 174          */
 175         dst = (void *)raw;
 176         for (i = 0, was_ld_map = false; i < fp->len; i++) {
 177                 dst[i] = fp->insnsi[i];
 178                 if (!was_ld_map &&
 179                     dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
 180                     dst[i].src_reg == BPF_PSEUDO_MAP_FD) {
 181                         was_ld_map = true;
 182                         dst[i].imm = 0;
 183                 } else if (was_ld_map &&
 184                            dst[i].code == 0 &&
 185                            dst[i].dst_reg == 0 &&
 186                            dst[i].src_reg == 0 &&
 187                            dst[i].off == 0) {
 188                         was_ld_map = false;
 189                         dst[i].imm = 0;
 190                 } else {
 191                         was_ld_map = false;
 192                 }
 193         }
 194
 195         psize = bpf_prog_insn_size(fp);
 196         memset(&raw[psize], 0, raw_size - psize);
 197         raw[psize++] = 0x80;
 198
 199         bsize  = round_up(psize, SHA_MESSAGE_BYTES);
 200         blocks = bsize / SHA_MESSAGE_BYTES;
 201         todo   = raw;
 202         if (bsize - psize >= sizeof(__be64)) {
 203                 bits = (__be64 *)(todo + bsize - sizeof(__be64));
 204         } else {
 205                 bits = (__be64 *)(todo + bsize + bits_offset);
 206                 blocks++;
 207         }
 208         *bits = cpu_to_be64((psize - 1) << 3);
 209
 210         while (blocks--) {
 211                 sha_transform(digest, todo, ws);
 212                 todo += SHA_MESSAGE_BYTES;
 213         }
 214
 215         result = (__force __be32 *)digest;
 216         for (i = 0; i < SHA_DIGEST_WORDS; i++)
 217                 result[i] = cpu_to_be32(digest[i]);
 218         memcpy(fp->tag, result, sizeof(fp->tag));
 219
 220         vfree(raw);
 221         return 0;
 222 }
 223
 224 static bool bpf_is_jmp_and_has_target(const struct bpf_insn *insn)
 225 {
 226         return BPF_CLASS(insn->code) == BPF_JMP  &&
 227                /* Call and Exit are both special jumps with no
 228                 * target inside the BPF instruction image.
 229                 */
 230                BPF_OP(insn->code) != BPF_CALL &&
 231                BPF_OP(insn->code) != BPF_EXIT;
 232 }
 233
 234 static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta)
 235 {
 236         struct bpf_insn *insn = prog->insnsi;
 237         u32 i, insn_cnt = prog->len;
 238
 239         for (i = 0; i < insn_cnt; i++, insn++) {
 240                 if (!bpf_is_jmp_and_has_target(insn))
 241                         continue;
 242
 243                 /* Adjust offset of jmps if we cross boundaries. */
 244                 if (i < pos && i + insn->off + 1 > pos)
 245                         insn->off += delta;
 246                 else if (i > pos + delta && i + insn->off + 1 <= pos + delta)
 247                         insn->off -= delta;
 248         }
 249 }
 250
 251 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
 252                                        const struct bpf_insn *patch, u32 len)
 253 {
 254         u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
 255         struct bpf_prog *prog_adj;
 256
 257         /* Since our patchlet doesn't expand the image, we're done. */
 258         if (insn_delta == 0) {
 259                 memcpy(prog->insnsi + off, patch, sizeof(*patch));
 260                 return prog;
 261         }
 262
 263         insn_adj_cnt = prog->len + insn_delta;
 264
 265         /* Several new instructions need to be inserted. Make room
 266          * for them. Likely, there's no need for a new allocation as
 267          * last page could have large enough tailroom.
 268          */
 269         prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
 270                                     GFP_USER);
 271         if (!prog_adj)
 272                 return NULL;
 273
 274         prog_adj->len = insn_adj_cnt;
 275
 276         /* Patching happens in 3 steps:
 277          *
 278          * 1) Move over tail of insnsi from next instruction onwards,
 279          *    so we can patch the single target insn with one or more
 280          *    new ones (patching is always from 1 to n insns, n > 0).
 281          * 2) Inject new instructions at the target location.
 282          * 3) Adjust branch offsets if necessary.
 283          */
 284         insn_rest = insn_adj_cnt - off - len;
 285
 286         memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
 287                 sizeof(*patch) * insn_rest);
 288         memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
 289
 290         bpf_adj_branches(prog_adj, off, insn_delta);
 291
 292         return prog_adj;
 293 }
 294
 295 #ifdef CONFIG_BPF_JIT
 296 static __always_inline void
 297 bpf_get_prog_addr_region(const struct bpf_prog *prog,
 298                          unsigned long *symbol_start,
 299                          unsigned long *symbol_end)
 300 {
 301         const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);
 302         unsigned long addr = (unsigned long)hdr;
 303
 304         WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
 305
 306         *symbol_start = addr;
 307         *symbol_end   = addr + hdr->pages * PAGE_SIZE;
 308 }
 309
 310 static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
 311 {
 312         BUILD_BUG_ON(sizeof("bpf_prog_") +
 313                      sizeof(prog->tag) * 2 + 1 > KSYM_NAME_LEN);
 314
 315         sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
 316         sym  = bin2hex(sym, prog->tag, sizeof(prog->tag));
 317         *sym = 0;
 318 }
 319
 320 static __always_inline unsigned long
 321 bpf_get_prog_addr_start(struct latch_tree_node *n)
 322 {
 323         unsigned long symbol_start, symbol_end;
 324         const struct bpf_prog_aux *aux;
 325
 326         aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
 327         bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
 328
 329         return symbol_start;
 330 }
 331
 332 static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
 333                                           struct latch_tree_node *b)
 334 {
 335         return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b);
 336 }
 337
 338 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
 339 {
 340         unsigned long val = (unsigned long)key;
 341         unsigned long symbol_start, symbol_end;
 342         const struct bpf_prog_aux *aux;
 343
 344         aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
 345         bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
 346
 347         if (val < symbol_start)
 348                 return -1;
 349         if (val >= symbol_end)
 350                 return  1;
 351
 352         return 0;
 353 }
 354
 355 static const struct latch_tree_ops bpf_tree_ops = {
 356         .less   = bpf_tree_less,
 357         .comp   = bpf_tree_comp,
 358 };
 359
 360 static DEFINE_SPINLOCK(bpf_lock);
 361 static LIST_HEAD(bpf_kallsyms);
 362 static struct latch_tree_root bpf_tree __cacheline_aligned;
 363
 364 int bpf_jit_kallsyms __read_mostly;
 365
 366 static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)
 367 {
 368         WARN_ON_ONCE(!list_empty(&aux->ksym_lnode));
 369         list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms);
 370         latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
 371 }
 372
 373 static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux)
 374 {
 375         if (list_empty(&aux->ksym_lnode))
 376                 return;
 377
 378         latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
 379         list_del_rcu(&aux->ksym_lnode);
 380 }
 381
 382 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
 383 {
 384         return fp->jited && !bpf_prog_was_classic(fp);
 385 }
 386
 387 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
 388 {
 389         return list_empty(&fp->aux->ksym_lnode) ||
 390                fp->aux->ksym_lnode.prev == LIST_POISON2;
 391 }
 392
 393 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
 394 {
 395         if (!bpf_prog_kallsyms_candidate(fp) ||
 396             !capable(CAP_SYS_ADMIN))
 397                 return;
 398
 399         spin_lock_bh(&bpf_lock);
 400         bpf_prog_ksym_node_add(fp->aux);
 401         spin_unlock_bh(&bpf_lock);
 402 }
 403
 404 void bpf_prog_kallsyms_del(struct bpf_prog *fp)
 405 {
 406         if (!bpf_prog_kallsyms_candidate(fp))
 407                 return;
 408
 409         spin_lock_bh(&bpf_lock);
 410         bpf_prog_ksym_node_del(fp->aux);
 411         spin_unlock_bh(&bpf_lock);
 412 }
 413
 414 static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
 415 {
 416         struct latch_tree_node *n;
 417
 418         if (!bpf_jit_kallsyms_enabled())
 419                 return NULL;
 420
 421         n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
 422         return n ?
 423                container_of(n, struct bpf_prog_aux, ksym_tnode)->prog :
 424                NULL;
 425 }
 426
 427 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
 428                                  unsigned long *off, char *sym)
 429 {
 430         unsigned long symbol_start, symbol_end;
 431         struct bpf_prog *prog;
 432         char *ret = NULL;
 433
 434         rcu_read_lock();
 435         prog = bpf_prog_kallsyms_find(addr);
 436         if (prog) {
 437                 bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end);
 438                 bpf_get_prog_name(prog, sym);
 439
 440                 ret = sym;
 441                 if (size)
 442                         *size = symbol_end - symbol_start;
 443                 if (off)
 444                         *off  = addr - symbol_start;
 445         }
 446         rcu_read_unlock();
 447
 448         return ret;
 449 }
 450
 451 bool is_bpf_text_address(unsigned long addr)
 452 {
 453         bool ret;
 454
 455         rcu_read_lock();
 456         ret = bpf_prog_kallsyms_find(addr) != NULL;
 457         rcu_read_unlock();
 458
 459         return ret;
 460 }
 461
 462 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 463                     char *sym)
 464 {
 465         unsigned long symbol_start, symbol_end;
 466         struct bpf_prog_aux *aux;
 467         unsigned int it = 0;
 468         int ret = -ERANGE;
 469
 470         if (!bpf_jit_kallsyms_enabled())
 471                 return ret;
 472
 473         rcu_read_lock();
 474         list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) {
 475                 if (it++ != symnum)
 476                         continue;
 477
 478                 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
 479                 bpf_get_prog_name(aux->prog, sym);
 480
 481                 *value = symbol_start;
 482                 *type  = BPF_SYM_ELF_TYPE;
 483
 484                 ret = 0;
 485                 break;
 486         }
 487         rcu_read_unlock();
 488
 489         return ret;
 490 }
 491
 492 struct bpf_binary_header *
 493 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 494                      unsigned int alignment,
 495                      bpf_jit_fill_hole_t bpf_fill_ill_insns)
 496 {
 497         struct bpf_binary_header *hdr;
 498         unsigned int size, hole, start;
 499
 500         /* Most of BPF filters are really small, but if some of them
 501          * fill a page, allow at least 128 extra bytes to insert a
 502          * random section of illegal instructions.
 503          */
 504         size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
 505         hdr = module_alloc(size);
 506         if (hdr == NULL)
 507                 return NULL;
 508
 509         /* Fill space with illegal/arch-dep instructions. */
 510         bpf_fill_ill_insns(hdr, size);
 511
 512         hdr->pages = size / PAGE_SIZE;
 513         hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
 514                      PAGE_SIZE - sizeof(*hdr));
 515         start = (get_random_int() % hole) & ~(alignment - 1);
 516
 517         /* Leave a random number of instructions before BPF code. */
 518         *image_ptr = &hdr->image[start];
 519
 520         return hdr;
 521 }
 522
 523 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
 524 {
 525         module_memfree(hdr);
 526 }
 527
 528 /* This symbol is only overridden by archs that have different
 529  * requirements than the usual eBPF JITs, f.e. when they only
 530  * implement cBPF JIT, do not set images read-only, etc.
 531  */
 532 void __weak bpf_jit_free(struct bpf_prog *fp)
 533 {
 534         if (fp->jited) {
 535                 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
 536
 537                 bpf_jit_binary_unlock_ro(hdr);
 538                 bpf_jit_binary_free(hdr);
 539
 540                 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
 541         }
 542
 543         bpf_prog_unlock_free(fp);
 544 }
 545
 546 int bpf_jit_harden __read_mostly;
 547
 548 static int bpf_jit_blind_insn(const struct bpf_insn *from,
 549                               const struct bpf_insn *aux,
 550                               struct bpf_insn *to_buff)
 551 {
 552         struct bpf_insn *to = to_buff;
 553         u32 imm_rnd = get_random_int();
 554         s16 off;
 555
 556         BUILD_BUG_ON(BPF_REG_AX  + 1 != MAX_BPF_JIT_REG);
 557         BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
 558
 559         if (from->imm == 0 &&
 560             (from->code == (BPF_ALU   | BPF_MOV | BPF_K) ||
 561              from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
 562                 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
 563                 goto out;
 564         }
 565
 566         switch (from->code) {
 567         case BPF_ALU | BPF_ADD | BPF_K:
 568         case BPF_ALU | BPF_SUB | BPF_K:
 569         case BPF_ALU | BPF_AND | BPF_K:
 570         case BPF_ALU | BPF_OR  | BPF_K:
 571         case BPF_ALU | BPF_XOR | BPF_K:
 572         case BPF_ALU | BPF_MUL | BPF_K:
 573         case BPF_ALU | BPF_MOV | BPF_K:
 574         case BPF_ALU | BPF_DIV | BPF_K:
 575         case BPF_ALU | BPF_MOD | BPF_K:
 576                 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 577                 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 578                 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
 579                 break;
 580
 581         case BPF_ALU64 | BPF_ADD | BPF_K:
 582         case BPF_ALU64 | BPF_SUB | BPF_K:
 583         case BPF_ALU64 | BPF_AND | BPF_K:
 584         case BPF_ALU64 | BPF_OR  | BPF_K:
 585         case BPF_ALU64 | BPF_XOR | BPF_K:
 586         case BPF_ALU64 | BPF_MUL | BPF_K:
 587         case BPF_ALU64 | BPF_MOV | BPF_K:
 588         case BPF_ALU64 | BPF_DIV | BPF_K:
 589         case BPF_ALU64 | BPF_MOD | BPF_K:
 590                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 591                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 592                 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
 593                 break;
 594
 595         case BPF_JMP | BPF_JEQ  | BPF_K:
 596         case BPF_JMP | BPF_JNE  | BPF_K:
 597         case BPF_JMP | BPF_JGT  | BPF_K:
 598         case BPF_JMP | BPF_JLT  | BPF_K:
 599         case BPF_JMP | BPF_JGE  | BPF_K:
 600         case BPF_JMP | BPF_JLE  | BPF_K:
 601         case BPF_JMP | BPF_JSGT | BPF_K:
 602         case BPF_JMP | BPF_JSLT | BPF_K:
 603         case BPF_JMP | BPF_JSGE | BPF_K:
 604         case BPF_JMP | BPF_JSLE | BPF_K:
 605         case BPF_JMP | BPF_JSET | BPF_K:
 606                 /* Accommodate for extra offset in case of a backjump. */
 607                 off = from->off;
 608                 if (off < 0)
 609                         off -= 2;
 610                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 611                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 612                 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
 613                 break;
 614
 615         case BPF_LD | BPF_ABS | BPF_W:
 616         case BPF_LD | BPF_ABS | BPF_H:
 617         case BPF_LD | BPF_ABS | BPF_B:
 618                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 619                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 620                 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
 621                 break;
 622
 623         case BPF_LD | BPF_IND | BPF_W:
 624         case BPF_LD | BPF_IND | BPF_H:
 625         case BPF_LD | BPF_IND | BPF_B:
 626                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 627                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 628                 *to++ = BPF_ALU32_REG(BPF_ADD, BPF_REG_AX, from->src_reg);
 629                 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
 630                 break;
 631
 632         case BPF_LD | BPF_IMM | BPF_DW:
 633                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
 634                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 635                 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
 636                 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
 637                 break;
 638         case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
 639                 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
 640                 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 641                 *to++ = BPF_ALU64_REG(BPF_OR,  aux[0].dst_reg, BPF_REG_AX);
 642                 break;
 643
 644         case BPF_ST | BPF_MEM | BPF_DW:
 645         case BPF_ST | BPF_MEM | BPF_W:
 646         case BPF_ST | BPF_MEM | BPF_H:
 647         case BPF_ST | BPF_MEM | BPF_B:
 648                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 649                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 650                 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
 651                 break;
 652         }
 653 out:
 654         return to - to_buff;
 655 }
 656
 657 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
 658                                               gfp_t gfp_extra_flags)
 659 {
 660         gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
 661         struct bpf_prog *fp;
 662
 663         fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL);
 664         if (fp != NULL) {
 665                 kmemcheck_annotate_bitfield(fp, meta);
 666
 667                 /* aux->prog still points to the fp_other one, so
 668                  * when promoting the clone to the real program,
 669                  * this still needs to be adapted.
 670                  */
 671                 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
 672         }
 673
 674         return fp;
 675 }
 676
 677 static void bpf_prog_clone_free(struct bpf_prog *fp)
 678 {
 679         /* aux was stolen by the other clone, so we cannot free
 680          * it from this path! It will be freed eventually by the
 681          * other program on release.
 682          *
 683          * At this point, we don't need a deferred release since
 684          * clone is guaranteed to not be locked.
 685          */
 686         fp->aux = NULL;
 687         __bpf_prog_free(fp);
 688 }
 689
 690 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
 691 {
 692         /* We have to repoint aux->prog to self, as we don't
 693          * know whether fp here is the clone or the original.
 694          */
 695         fp->aux->prog = fp;
 696         bpf_prog_clone_free(fp_other);
 697 }
 698
 699 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
 700 {
 701         struct bpf_insn insn_buff[16], aux[2];
 702         struct bpf_prog *clone, *tmp;
 703         int insn_delta, insn_cnt;
 704         struct bpf_insn *insn;
 705         int i, rewritten;
 706
 707         if (!bpf_jit_blinding_enabled())
 708                 return prog;
 709
 710         clone = bpf_prog_clone_create(prog, GFP_USER);
 711         if (!clone)
 712                 return ERR_PTR(-ENOMEM);
 713
 714         insn_cnt = clone->len;
 715         insn = clone->insnsi;
 716
 717         for (i = 0; i < insn_cnt; i++, insn++) {
 718                 /* We temporarily need to hold the original ld64 insn
 719                  * so that we can still access the first part in the
 720                  * second blinding run.
 721                  */
 722                 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
 723                     insn[1].code == 0)
 724                         memcpy(aux, insn, sizeof(aux));
 725
 726                 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff);
 727                 if (!rewritten)
 728                         continue;
 729
 730                 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
 731                 if (!tmp) {
 732                         /* Patching may have repointed aux->prog during
 733                          * realloc from the original one, so we need to
 734                          * fix it up here on error.
 735                          */
 736                         bpf_jit_prog_release_other(prog, clone);
 737                         return ERR_PTR(-ENOMEM);
 738                 }
 739
 740                 clone = tmp;
 741                 insn_delta = rewritten - 1;
 742
 743                 /* Walk new program and skip insns we just inserted. */
 744                 insn = clone->insnsi + i + insn_delta;
 745                 insn_cnt += insn_delta;
 746                 i        += insn_delta;
 747         }
 748
 749         return clone;
 750 }
 751 #endif /* CONFIG_BPF_JIT */
 752
 753 /* Base function for offset calculation. Needs to go into .text section,
 754  * therefore keeping it non-static as well; will also be used by JITs
 755  * anyway later on, so do not let the compiler omit it.
 756  */
 757 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
 758 {
 759         return 0;
 760 }
 761 EXPORT_SYMBOL_GPL(__bpf_call_base);
 762
 763 /**
 764  *      __bpf_prog_run - run eBPF program on a given context
 765  *      @ctx: is the data we are operating on
 766  *      @insn: is the array of eBPF instructions
 767  *
 768  * Decode and execute eBPF instructions.
 769  */
 770 static unsigned int ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn,
 771                                     u64 *stack)
 772 {
 773         u64 tmp;
 774         static const void *jumptable[256] = {
 775                 [0 ... 255] = &&default_label,
 776                 /* Now overwrite non-defaults ... */
 777                 /* 32 bit ALU operations */
 778                 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
 779                 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
 780                 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
 781                 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
 782                 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
 783                 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
 784                 [BPF_ALU | BPF_OR | BPF_X]  = &&ALU_OR_X,
 785                 [BPF_ALU | BPF_OR | BPF_K]  = &&ALU_OR_K,
 786                 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
 787                 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
 788                 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
 789                 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
 790                 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
 791                 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
 792                 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
 793                 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
 794                 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
 795                 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
 796                 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
 797                 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
 798                 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
 799                 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
 800                 [BPF_ALU | BPF_NEG] = &&ALU_NEG,
 801                 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
 802                 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
 803                 /* 64 bit ALU operations */
 804                 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
 805                 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
 806                 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
 807                 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
 808                 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
 809                 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
 810                 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
 811                 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
 812                 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
 813                 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
 814                 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
 815                 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
 816                 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
 817                 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
 818                 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
 819                 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
 820                 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
 821                 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
 822                 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
 823                 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
 824                 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
 825                 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
 826                 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
 827                 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
 828                 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
 829                 /* Call instruction */
 830                 [BPF_JMP | BPF_CALL] = &&JMP_CALL,
 831                 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
 832                 /* Jumps */
 833                 [BPF_JMP | BPF_JA] = &&JMP_JA,
 834                 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
 835                 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
 836                 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
 837                 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
 838                 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
 839                 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
 840                 [BPF_JMP | BPF_JLT | BPF_X] = &&JMP_JLT_X,
 841                 [BPF_JMP | BPF_JLT | BPF_K] = &&JMP_JLT_K,
 842                 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
 843                 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
 844                 [BPF_JMP | BPF_JLE | BPF_X] = &&JMP_JLE_X,
 845                 [BPF_JMP | BPF_JLE | BPF_K] = &&JMP_JLE_K,
 846                 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
 847                 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
 848                 [BPF_JMP | BPF_JSLT | BPF_X] = &&JMP_JSLT_X,
 849                 [BPF_JMP | BPF_JSLT | BPF_K] = &&JMP_JSLT_K,
 850                 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
 851                 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
 852                 [BPF_JMP | BPF_JSLE | BPF_X] = &&JMP_JSLE_X,
 853                 [BPF_JMP | BPF_JSLE | BPF_K] = &&JMP_JSLE_K,
 854                 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
 855                 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
 856                 /* Program return */
 857                 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
 858                 /* Store instructions */
 859                 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
 860                 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
 861                 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
 862                 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
 863                 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
 864                 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
 865                 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
 866                 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
 867                 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
 868                 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
 869                 /* Load instructions */
 870                 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
 871                 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
 872                 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
 873                 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
 874                 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
 875                 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
 876                 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
 877                 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
 878                 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
 879                 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
 880                 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
 881         };
 882         u32 tail_call_cnt = 0;
 883         void *ptr;
 884         int off;
 885
 886 #define CONT     ({ insn++; goto select_insn; })
 887 #define CONT_JMP ({ insn++; goto select_insn; })
 888
 889 select_insn:
 890         goto *jumptable[insn->code];
 891
 892         /* ALU */
 893 #define ALU(OPCODE, OP)                 \
 894         ALU64_##OPCODE##_X:             \
 895                 DST = DST OP SRC;       \
 896                 CONT;                   \
 897         ALU_##OPCODE##_X:               \
 898                 DST = (u32) DST OP (u32) SRC;   \
 899                 CONT;                   \
 900         ALU64_##OPCODE##_K:             \
 901                 DST = DST OP IMM;               \
 902                 CONT;                   \
 903         ALU_##OPCODE##_K:               \
 904                 DST = (u32) DST OP (u32) IMM;   \
 905                 CONT;
 906
 907         ALU(ADD,  +)
 908         ALU(SUB,  -)
 909         ALU(AND,  &)
 910         ALU(OR,   |)
 911         ALU(LSH, <<)
 912         ALU(RSH, >>)
 913         ALU(XOR,  ^)
 914         ALU(MUL,  *)
 915 #undef ALU
 916         ALU_NEG:
 917                 DST = (u32) -DST;
 918                 CONT;
 919         ALU64_NEG:
 920                 DST = -DST;
 921                 CONT;
 922         ALU_MOV_X:
 923                 DST = (u32) SRC;
 924                 CONT;
 925         ALU_MOV_K:
 926                 DST = (u32) IMM;
 927                 CONT;
 928         ALU64_MOV_X:
 929                 DST = SRC;
 930                 CONT;
 931         ALU64_MOV_K:
 932                 DST = IMM;
 933                 CONT;
 934         LD_IMM_DW:
 935                 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
 936                 insn++;
 937                 CONT;
 938         ALU64_ARSH_X:
 939                 (*(s64 *) &DST) >>= SRC;
 940                 CONT;
 941         ALU64_ARSH_K:
 942                 (*(s64 *) &DST) >>= IMM;
 943                 CONT;
 944         ALU64_MOD_X:
 945                 if (unlikely(SRC == 0))
 946                         return 0;
 947                 div64_u64_rem(DST, SRC, &tmp);
 948                 DST = tmp;
 949                 CONT;
 950         ALU_MOD_X:
 951                 if (unlikely(SRC == 0))
 952                         return 0;
 953                 tmp = (u32) DST;
 954                 DST = do_div(tmp, (u32) SRC);
 955                 CONT;
 956         ALU64_MOD_K:
 957                 div64_u64_rem(DST, IMM, &tmp);
 958                 DST = tmp;
 959                 CONT;
 960         ALU_MOD_K:
 961                 tmp = (u32) DST;
 962                 DST = do_div(tmp, (u32) IMM);
 963                 CONT;
 964         ALU64_DIV_X:
 965                 if (unlikely(SRC == 0))
 966                         return 0;
 967                 DST = div64_u64(DST, SRC);
 968                 CONT;
 969         ALU_DIV_X:
 970                 if (unlikely(SRC == 0))
 971                         return 0;
 972                 tmp = (u32) DST;
 973                 do_div(tmp, (u32) SRC);
 974                 DST = (u32) tmp;
 975                 CONT;
 976         ALU64_DIV_K:
 977                 DST = div64_u64(DST, IMM);
 978                 CONT;
 979         ALU_DIV_K:
 980                 tmp = (u32) DST;
 981                 do_div(tmp, (u32) IMM);
 982                 DST = (u32) tmp;
 983                 CONT;
 984         ALU_END_TO_BE:
 985                 switch (IMM) {
 986                 case 16:
 987                         DST = (__force u16) cpu_to_be16(DST);
 988                         break;
 989                 case 32:
 990                         DST = (__force u32) cpu_to_be32(DST);
 991                         break;
 992                 case 64:
 993                         DST = (__force u64) cpu_to_be64(DST);
 994                         break;
 995                 }
 996                 CONT;
 997         ALU_END_TO_LE:
 998                 switch (IMM) {
 999                 case 16:
1000                         DST = (__force u16) cpu_to_le16(DST);
1001                         break;
1002                 case 32:
1003                         DST = (__force u32) cpu_to_le32(DST);
1004                         break;
1005                 case 64:
1006                         DST = (__force u64) cpu_to_le64(DST);
1007                         break;
1008                 }
1009                 CONT;
1010
1011         /* CALL */
1012         JMP_CALL:
1013                 /* Function call scratches BPF_R1-BPF_R5 registers,
1014                  * preserves BPF_R6-BPF_R9, and stores return value
1015                  * into BPF_R0.
1016                  */
1017                 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
1018                                                        BPF_R4, BPF_R5);
1019                 CONT;
1020
1021         JMP_TAIL_CALL: {
1022                 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
1023                 struct bpf_array *array = container_of(map, struct bpf_array, map);
1024                 struct bpf_prog *prog;
1025                 u32 index = BPF_R3;
1026
1027                 if (unlikely(index >= array->map.max_entries))
1028                         goto out;
1029                 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
1030                         goto out;
1031
1032                 tail_call_cnt++;
1033
1034                 prog = READ_ONCE(array->ptrs[index]);
1035                 if (!prog)
1036                         goto out;
1037
1038                 /* ARG1 at this point is guaranteed to point to CTX from
1039                  * the verifier side due to the fact that the tail call is
1040                  * handeled like a helper, that is, bpf_tail_call_proto,
1041                  * where arg1_type is ARG_PTR_TO_CTX.
1042                  */
1043                 insn = prog->insnsi;
1044                 goto select_insn;
1045 out:
1046                 CONT;
1047         }
1048         /* JMP */
1049         JMP_JA:
1050                 insn += insn->off;
1051                 CONT;
1052         JMP_JEQ_X:
1053                 if (DST == SRC) {
1054                         insn += insn->off;
1055                         CONT_JMP;
1056                 }
1057                 CONT;
1058         JMP_JEQ_K:
1059                 if (DST == IMM) {
1060                         insn += insn->off;
1061                         CONT_JMP;
1062                 }
1063                 CONT;
1064         JMP_JNE_X:
1065                 if (DST != SRC) {
1066                         insn += insn->off;
1067                         CONT_JMP;
1068                 }
1069                 CONT;
1070         JMP_JNE_K:
1071                 if (DST != IMM) {
1072                         insn += insn->off;
1073                         CONT_JMP;
1074                 }
1075                 CONT;
1076         JMP_JGT_X:
1077                 if (DST > SRC) {
1078                         insn += insn->off;
1079                         CONT_JMP;
1080                 }
1081                 CONT;
1082         JMP_JGT_K:
1083                 if (DST > IMM) {
1084                         insn += insn->off;
1085                         CONT_JMP;
1086                 }
1087                 CONT;
1088         JMP_JLT_X:
1089                 if (DST < SRC) {
1090                         insn += insn->off;
1091                         CONT_JMP;
1092                 }
1093                 CONT;
1094         JMP_JLT_K:
1095                 if (DST < IMM) {
1096                         insn += insn->off;
1097                         CONT_JMP;
1098                 }
1099                 CONT;
1100         JMP_JGE_X:
1101                 if (DST >= SRC) {
1102                         insn += insn->off;
1103                         CONT_JMP;
1104                 }
1105                 CONT;
1106         JMP_JGE_K:
1107                 if (DST >= IMM) {
1108                         insn += insn->off;
1109                         CONT_JMP;
1110                 }
1111                 CONT;
1112         JMP_JLE_X:
1113                 if (DST <= SRC) {
1114                         insn += insn->off;
1115                         CONT_JMP;
1116                 }
1117                 CONT;
1118         JMP_JLE_K:
1119                 if (DST <= IMM) {
1120                         insn += insn->off;
1121                         CONT_JMP;
1122                 }
1123                 CONT;
1124         JMP_JSGT_X:
1125                 if (((s64) DST) > ((s64) SRC)) {
1126                         insn += insn->off;
1127                         CONT_JMP;
1128                 }
1129                 CONT;
1130         JMP_JSGT_K:
1131                 if (((s64) DST) > ((s64) IMM)) {
1132                         insn += insn->off;
1133                         CONT_JMP;
1134                 }
1135                 CONT;
1136         JMP_JSLT_X:
1137                 if (((s64) DST) < ((s64) SRC)) {
1138                         insn += insn->off;
1139                         CONT_JMP;
1140                 }
1141                 CONT;
1142         JMP_JSLT_K:
1143                 if (((s64) DST) < ((s64) IMM)) {
1144                         insn += insn->off;
1145                         CONT_JMP;
1146                 }
1147                 CONT;
1148         JMP_JSGE_X:
1149                 if (((s64) DST) >= ((s64) SRC)) {
1150                         insn += insn->off;
1151                         CONT_JMP;
1152                 }
1153                 CONT;
1154         JMP_JSGE_K:
1155                 if (((s64) DST) >= ((s64) IMM)) {
1156                         insn += insn->off;
1157                         CONT_JMP;
1158                 }
1159                 CONT;
1160         JMP_JSLE_X:
1161                 if (((s64) DST) <= ((s64) SRC)) {
1162                         insn += insn->off;
1163                         CONT_JMP;
1164                 }
1165                 CONT;
1166         JMP_JSLE_K:
1167                 if (((s64) DST) <= ((s64) IMM)) {
1168                         insn += insn->off;
1169                         CONT_JMP;
1170                 }
1171                 CONT;
1172         JMP_JSET_X:
1173                 if (DST & SRC) {
1174                         insn += insn->off;
1175                         CONT_JMP;
1176                 }
1177                 CONT;
1178         JMP_JSET_K:
1179                 if (DST & IMM) {
1180                         insn += insn->off;
1181                         CONT_JMP;
1182                 }
1183                 CONT;
1184         JMP_EXIT:
1185                 return BPF_R0;
1186
1187         /* STX and ST and LDX*/
1188 #define LDST(SIZEOP, SIZE)                                              \
1189         STX_MEM_##SIZEOP:                                               \
1190                 *(SIZE *)(unsigned long) (DST + insn->off) = SRC;       \
1191                 CONT;                                                   \
1192         ST_MEM_##SIZEOP:                                                \
1193                 *(SIZE *)(unsigned long) (DST + insn->off) = IMM;       \
1194                 CONT;                                                   \
1195         LDX_MEM_##SIZEOP:                                               \
1196                 DST = *(SIZE *)(unsigned long) (SRC + insn->off);       \
1197                 CONT;
1198
1199         LDST(B,   u8)
1200         LDST(H,  u16)
1201         LDST(W,  u32)
1202         LDST(DW, u64)
1203 #undef LDST
1204         STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
1205                 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
1206                            (DST + insn->off));
1207                 CONT;
1208         STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
1209                 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
1210                              (DST + insn->off));
1211                 CONT;
1212         LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
1213                 off = IMM;
1214 load_word:
1215                 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are only
1216                  * appearing in the programs where ctx == skb
1217                  * (see may_access_skb() in the verifier). All programs
1218                  * keep 'ctx' in regs[BPF_REG_CTX] == BPF_R6,
1219                  * bpf_convert_filter() saves it in BPF_R6, internal BPF
1220                  * verifier will check that BPF_R6 == ctx.
1221                  *
1222                  * BPF_ABS and BPF_IND are wrappers of function calls,
1223                  * so they scratch BPF_R1-BPF_R5 registers, preserve
1224                  * BPF_R6-BPF_R9, and store return value into BPF_R0.
1225                  *
1226                  * Implicit input:
1227                  *   ctx == skb == BPF_R6 == CTX
1228                  *
1229                  * Explicit input:
1230                  *   SRC == any register
1231                  *   IMM == 32-bit immediate
1232                  *
1233                  * Output:
1234                  *   BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
1235                  */
1236
1237                 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
1238                 if (likely(ptr != NULL)) {
1239                         BPF_R0 = get_unaligned_be32(ptr);
1240                         CONT;
1241                 }
1242
1243                 return 0;
1244         LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
1245                 off = IMM;
1246 load_half:
1247                 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
1248                 if (likely(ptr != NULL)) {
1249                         BPF_R0 = get_unaligned_be16(ptr);
1250                         CONT;
1251                 }
1252
1253                 return 0;
1254         LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
1255                 off = IMM;
1256 load_byte:
1257                 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
1258                 if (likely(ptr != NULL)) {
1259                         BPF_R0 = *(u8 *)ptr;
1260                         CONT;
1261                 }
1262
1263                 return 0;
1264         LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
1265                 off = IMM + SRC;
1266                 goto load_word;
1267         LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
1268                 off = IMM + SRC;
1269                 goto load_half;
1270         LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
1271                 off = IMM + SRC;
1272                 goto load_byte;
1273
1274         default_label:
1275                 /* If we ever reach this, we have a bug somewhere. */
1276                 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
1277                 return 0;
1278 }
1279 STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */
1280
1281 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size
1282 #define DEFINE_BPF_PROG_RUN(stack_size) \
1283 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
1284 { \
1285         u64 stack[stack_size / sizeof(u64)]; \
1286         u64 regs[MAX_BPF_REG]; \
1287 \
1288         FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
1289         ARG1 = (u64) (unsigned long) ctx; \
1290         return ___bpf_prog_run(regs, insn, stack); \
1291 }
1292
1293 #define EVAL1(FN, X) FN(X)
1294 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
1295 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
1296 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
1297 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
1298 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
1299
1300 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
1301 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
1302 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
1303
1304 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
1305
1306 static unsigned int (*interpreters[])(const void *ctx,
1307                                       const struct bpf_insn *insn) = {
1308 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
1309 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
1310 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
1311 };
1312
1313 bool bpf_prog_array_compatible(struct bpf_array *array,
1314                                const struct bpf_prog *fp)
1315 {
1316         if (!array->owner_prog_type) {
1317                 /* There's no owner yet where we could check for
1318                  * compatibility.
1319                  */
1320                 array->owner_prog_type = fp->type;
1321                 array->owner_jited = fp->jited;
1322
1323                 return true;
1324         }
1325
1326         return array->owner_prog_type == fp->type &&
1327                array->owner_jited == fp->jited;
1328 }
1329
1330 static int bpf_check_tail_call(const struct bpf_prog *fp)
1331 {
1332         struct bpf_prog_aux *aux = fp->aux;
1333         int i;
1334
1335         for (i = 0; i < aux->used_map_cnt; i++) {
1336                 struct bpf_map *map = aux->used_maps[i];
1337                 struct bpf_array *array;
1338
1339                 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
1340                         continue;
1341
1342                 array = container_of(map, struct bpf_array, map);
1343                 if (!bpf_prog_array_compatible(array, fp))
1344                         return -EINVAL;
1345         }
1346
1347         return 0;
1348 }
1349
1350 /**
1351  *      bpf_prog_select_runtime - select exec runtime for BPF program
1352  *      @fp: bpf_prog populated with internal BPF program
1353  *      @err: pointer to error variable
1354  *
1355  * Try to JIT eBPF program, if JIT is not available, use interpreter.
1356  * The BPF program will be executed via BPF_PROG_RUN() macro.
1357  */
1358 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
1359 {
1360         u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
1361
1362         fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
1363
1364         /* eBPF JITs can rewrite the program in case constant
1365          * blinding is active. However, in case of error during
1366          * blinding, bpf_int_jit_compile() must always return a
1367          * valid program, which in this case would simply not
1368          * be JITed, but falls back to the interpreter.
1369          */
1370         fp = bpf_int_jit_compile(fp);
1371         bpf_prog_lock_ro(fp);
1372
1373         /* The tail call compatibility check can only be done at
1374          * this late stage as we need to determine, if we deal
1375          * with JITed or non JITed program concatenations and not
1376          * all eBPF JITs might immediately support all features.
1377          */
1378         *err = bpf_check_tail_call(fp);
1379
1380         return fp;
1381 }
1382 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
1383
1384 static void bpf_prog_free_deferred(struct work_struct *work)
1385 {
1386         struct bpf_prog_aux *aux;
1387
1388         aux = container_of(work, struct bpf_prog_aux, work);
1389         bpf_jit_free(aux->prog);
1390 }
1391
1392 /* Free internal BPF program */
1393 void bpf_prog_free(struct bpf_prog *fp)
1394 {
1395         struct bpf_prog_aux *aux = fp->aux;
1396
1397         INIT_WORK(&aux->work, bpf_prog_free_deferred);
1398         schedule_work(&aux->work);
1399 }
1400 EXPORT_SYMBOL_GPL(bpf_prog_free);
1401
1402 /* RNG for unpriviledged user space with separated state from prandom_u32(). */
1403 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
1404
1405 void bpf_user_rnd_init_once(void)
1406 {
1407         prandom_init_once(&bpf_user_rnd_state);
1408 }
1409
1410 BPF_CALL_0(bpf_user_rnd_u32)
1411 {
1412         /* Should someone ever have the rather unwise idea to use some
1413          * of the registers passed into this function, then note that
1414          * this function is called from native eBPF and classic-to-eBPF
1415          * transformations. Register assignments from both sides are
1416          * different, f.e. classic always sets fn(ctx, A, X) here.
1417          */
1418         struct rnd_state *state;
1419         u32 res;
1420
1421         state = &get_cpu_var(bpf_user_rnd_state);
1422         res = prandom_u32_state(state);
1423         put_cpu_var(bpf_user_rnd_state);
1424
1425         return res;
1426 }
1427
1428 /* Weak definitions of helper functions in case we don't have bpf syscall. */
1429 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
1430 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
1431 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
1432
1433 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
1434 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
1435 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
1436 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
1437
1438 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
1439 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
1440 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
1441 const struct bpf_func_proto bpf_sock_map_update_proto __weak;
1442
1443 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
1444 {
1445         return NULL;
1446 }
1447
1448 u64 __weak
1449 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
1450                  void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
1451 {
1452         return -ENOTSUPP;
1453 }
1454
1455 /* Always built-in helper functions. */
1456 const struct bpf_func_proto bpf_tail_call_proto = {
1457         .func           = NULL,
1458         .gpl_only       = false,
1459         .ret_type       = RET_VOID,
1460         .arg1_type      = ARG_PTR_TO_CTX,
1461         .arg2_type      = ARG_CONST_MAP_PTR,
1462         .arg3_type      = ARG_ANYTHING,
1463 };
1464
1465 /* Stub for JITs that only support cBPF. eBPF programs are interpreted.
1466  * It is encouraged to implement bpf_int_jit_compile() instead, so that
1467  * eBPF and implicitly also cBPF can get JITed!
1468  */
1469 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
1470 {
1471         return prog;
1472 }
1473
1474 /* Stub for JITs that support eBPF. All cBPF code gets transformed into
1475  * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
1476  */
1477 void __weak bpf_jit_compile(struct bpf_prog *prog)
1478 {
1479 }
1480
1481 bool __weak bpf_helper_changes_pkt_data(void *func)
1482 {
1483         return false;
1484 }
1485
1486 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
1487  * skb_copy_bits(), so provide a weak definition of it for NET-less config.
1488  */
1489 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
1490                          int len)
1491 {
1492         return -EFAULT;
1493 }
1494
1495 /* All definitions of tracepoints related to BPF. */
1496 #define CREATE_TRACE_POINTS
1497 #include <linux/bpf_trace.h>
1498
1499 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
1500
1501 EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_get_type);
1502 EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_put_rcu);