include/linux/filter.h

   1 /*
   2  * Linux Socket Filter Data Structures
   3  */
   4 #ifndef __LINUX_FILTER_H__
   5 #define __LINUX_FILTER_H__
   6
   7 #include <stdarg.h>
   8
   9 #include <linux/atomic.h>
  10 #include <linux/compat.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/linkage.h>
  13 #include <linux/printk.h>
  14 #include <linux/workqueue.h>
  15 #include <linux/sched.h>
  16 #include <linux/capability.h>
  17
  18 #include <net/sch_generic.h>
  19
  20 #include <asm/cacheflush.h>
  21
  22 #include <uapi/linux/filter.h>
  23 #include <uapi/linux/bpf.h>
  24
  25 struct sk_buff;
  26 struct sock;
  27 struct seccomp_data;
  28 struct bpf_prog_aux;
  29
  30 /* ArgX, context and stack frame pointer register positions. Note,
  31  * Arg1, Arg2, Arg3, etc are used as argument mappings of function
  32  * calls in BPF_CALL instruction.
  33  */
  34 #define BPF_REG_ARG1    BPF_REG_1
  35 #define BPF_REG_ARG2    BPF_REG_2
  36 #define BPF_REG_ARG3    BPF_REG_3
  37 #define BPF_REG_ARG4    BPF_REG_4
  38 #define BPF_REG_ARG5    BPF_REG_5
  39 #define BPF_REG_CTX     BPF_REG_6
  40 #define BPF_REG_FP      BPF_REG_10
  41
  42 /* Additional register mappings for converted user programs. */
  43 #define BPF_REG_A       BPF_REG_0
  44 #define BPF_REG_X       BPF_REG_7
  45 #define BPF_REG_TMP     BPF_REG_8
  46
  47 /* Kernel hidden auxiliary/helper register for hardening step.
  48  * Only used by eBPF JITs. It's nothing more than a temporary
  49  * register that JITs use internally, only that here it's part
  50  * of eBPF instructions that have been rewritten for blinding
  51  * constants. See JIT pre-step in bpf_jit_blind_constants().
  52  */
  53 #define BPF_REG_AX              MAX_BPF_REG
  54 #define MAX_BPF_JIT_REG         (MAX_BPF_REG + 1)
  55
  56 /* BPF program can access up to 512 bytes of stack space. */
  57 #define MAX_BPF_STACK   512
  58
  59 /* Helper macros for filter block array initializers. */
  60
  61 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
  62
  63 #define BPF_ALU64_REG(OP, DST, SRC)                             \
  64         ((struct bpf_insn) {                                    \
  65                 .code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,        \
  66                 .dst_reg = DST,                                 \
  67                 .src_reg = SRC,                                 \
  68                 .off   = 0,                                     \
  69                 .imm   = 0 })
  70
  71 #define BPF_ALU32_REG(OP, DST, SRC)                             \
  72         ((struct bpf_insn) {                                    \
  73                 .code  = BPF_ALU | BPF_OP(OP) | BPF_X,          \
  74                 .dst_reg = DST,                                 \
  75                 .src_reg = SRC,                                 \
  76                 .off   = 0,                                     \
  77                 .imm   = 0 })
  78
  79 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
  80
  81 #define BPF_ALU64_IMM(OP, DST, IMM)                             \
  82         ((struct bpf_insn) {                                    \
  83                 .code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,        \
  84                 .dst_reg = DST,                                 \
  85                 .src_reg = 0,                                   \
  86                 .off   = 0,                                     \
  87                 .imm   = IMM })
  88
  89 #define BPF_ALU32_IMM(OP, DST, IMM)                             \
  90         ((struct bpf_insn) {                                    \
  91                 .code  = BPF_ALU | BPF_OP(OP) | BPF_K,          \
  92                 .dst_reg = DST,                                 \
  93                 .src_reg = 0,                                   \
  94                 .off   = 0,                                     \
  95                 .imm   = IMM })
  96
  97 /* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
  98
  99 #define BPF_ENDIAN(TYPE, DST, LEN)                              \
 100         ((struct bpf_insn) {                                    \
 101                 .code  = BPF_ALU | BPF_END | BPF_SRC(TYPE),     \
 102                 .dst_reg = DST,                                 \
 103                 .src_reg = 0,                                   \
 104                 .off   = 0,                                     \
 105                 .imm   = LEN })
 106
 107 /* Short form of mov, dst_reg = src_reg */
 108
 109 #define BPF_MOV64_REG(DST, SRC)                                 \
 110         ((struct bpf_insn) {                                    \
 111                 .code  = BPF_ALU64 | BPF_MOV | BPF_X,           \
 112                 .dst_reg = DST,                                 \
 113                 .src_reg = SRC,                                 \
 114                 .off   = 0,                                     \
 115                 .imm   = 0 })
 116
 117 #define BPF_MOV32_REG(DST, SRC)                                 \
 118         ((struct bpf_insn) {                                    \
 119                 .code  = BPF_ALU | BPF_MOV | BPF_X,             \
 120                 .dst_reg = DST,                                 \
 121                 .src_reg = SRC,                                 \
 122                 .off   = 0,                                     \
 123                 .imm   = 0 })
 124
 125 /* Short form of mov, dst_reg = imm32 */
 126
 127 #define BPF_MOV64_IMM(DST, IMM)                                 \
 128         ((struct bpf_insn) {                                    \
 129                 .code  = BPF_ALU64 | BPF_MOV | BPF_K,           \
 130                 .dst_reg = DST,                                 \
 131                 .src_reg = 0,                                   \
 132                 .off   = 0,                                     \
 133                 .imm   = IMM })
 134
 135 #define BPF_MOV32_IMM(DST, IMM)                                 \
 136         ((struct bpf_insn) {                                    \
 137                 .code  = BPF_ALU | BPF_MOV | BPF_K,             \
 138                 .dst_reg = DST,                                 \
 139                 .src_reg = 0,                                   \
 140                 .off   = 0,                                     \
 141                 .imm   = IMM })
 142
 143 /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
 144 #define BPF_LD_IMM64(DST, IMM)                                  \
 145         BPF_LD_IMM64_RAW(DST, 0, IMM)
 146
 147 #define BPF_LD_IMM64_RAW(DST, SRC, IMM)                         \
 148         ((struct bpf_insn) {                                    \
 149                 .code  = BPF_LD | BPF_DW | BPF_IMM,             \
 150                 .dst_reg = DST,                                 \
 151                 .src_reg = SRC,                                 \
 152                 .off   = 0,                                     \
 153                 .imm   = (__u32) (IMM) }),                      \
 154         ((struct bpf_insn) {                                    \
 155                 .code  = 0, /* zero is reserved opcode */       \
 156                 .dst_reg = 0,                                   \
 157                 .src_reg = 0,                                   \
 158                 .off   = 0,                                     \
 159                 .imm   = ((__u64) (IMM)) >> 32 })
 160
 161 /* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
 162 #define BPF_LD_MAP_FD(DST, MAP_FD)                              \
 163         BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
 164
 165 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
 166
 167 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM)                      \
 168         ((struct bpf_insn) {                                    \
 169                 .code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),   \
 170                 .dst_reg = DST,                                 \
 171                 .src_reg = SRC,                                 \
 172                 .off   = 0,                                     \
 173                 .imm   = IMM })
 174
 175 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM)                      \
 176         ((struct bpf_insn) {                                    \
 177                 .code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),     \
 178                 .dst_reg = DST,                                 \
 179                 .src_reg = SRC,                                 \
 180                 .off   = 0,                                     \
 181                 .imm   = IMM })
 182
 183 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
 184
 185 #define BPF_LD_ABS(SIZE, IMM)                                   \
 186         ((struct bpf_insn) {                                    \
 187                 .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,     \
 188                 .dst_reg = 0,                                   \
 189                 .src_reg = 0,                                   \
 190                 .off   = 0,                                     \
 191                 .imm   = IMM })
 192
 193 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
 194
 195 #define BPF_LD_IND(SIZE, SRC, IMM)                              \
 196         ((struct bpf_insn) {                                    \
 197                 .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,     \
 198                 .dst_reg = 0,                                   \
 199                 .src_reg = SRC,                                 \
 200                 .off   = 0,                                     \
 201                 .imm   = IMM })
 202
 203 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */
 204
 205 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF)                        \
 206         ((struct bpf_insn) {                                    \
 207                 .code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,    \
 208                 .dst_reg = DST,                                 \
 209                 .src_reg = SRC,                                 \
 210                 .off   = OFF,                                   \
 211                 .imm   = 0 })
 212
 213 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */
 214
 215 #define BPF_STX_MEM(SIZE, DST, SRC, OFF)                        \
 216         ((struct bpf_insn) {                                    \
 217                 .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,    \
 218                 .dst_reg = DST,                                 \
 219                 .src_reg = SRC,                                 \
 220                 .off   = OFF,                                   \
 221                 .imm   = 0 })
 222
 223 /* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */
 224
 225 #define BPF_STX_XADD(SIZE, DST, SRC, OFF)                       \
 226         ((struct bpf_insn) {                                    \
 227                 .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD,   \
 228                 .dst_reg = DST,                                 \
 229                 .src_reg = SRC,                                 \
 230                 .off   = OFF,                                   \
 231                 .imm   = 0 })
 232
 233 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
 234
 235 #define BPF_ST_MEM(SIZE, DST, OFF, IMM)                         \
 236         ((struct bpf_insn) {                                    \
 237                 .code  = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM,     \
 238                 .dst_reg = DST,                                 \
 239                 .src_reg = 0,                                   \
 240                 .off   = OFF,                                   \
 241                 .imm   = IMM })
 242
 243 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
 244
 245 #define BPF_JMP_REG(OP, DST, SRC, OFF)                          \
 246         ((struct bpf_insn) {                                    \
 247                 .code  = BPF_JMP | BPF_OP(OP) | BPF_X,          \
 248                 .dst_reg = DST,                                 \
 249                 .src_reg = SRC,                                 \
 250                 .off   = OFF,                                   \
 251                 .imm   = 0 })
 252
 253 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
 254
 255 #define BPF_JMP_IMM(OP, DST, IMM, OFF)                          \
 256         ((struct bpf_insn) {                                    \
 257                 .code  = BPF_JMP | BPF_OP(OP) | BPF_K,          \
 258                 .dst_reg = DST,                                 \
 259                 .src_reg = 0,                                   \
 260                 .off   = OFF,                                   \
 261                 .imm   = IMM })
 262
 263 /* Function call */
 264
 265 #define BPF_EMIT_CALL(FUNC)                                     \
 266         ((struct bpf_insn) {                                    \
 267                 .code  = BPF_JMP | BPF_CALL,                    \
 268                 .dst_reg = 0,                                   \
 269                 .src_reg = 0,                                   \
 270                 .off   = 0,                                     \
 271                 .imm   = ((FUNC) - __bpf_call_base) })
 272
 273 /* Raw code statement block */
 274
 275 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM)                  \
 276         ((struct bpf_insn) {                                    \
 277                 .code  = CODE,                                  \
 278                 .dst_reg = DST,                                 \
 279                 .src_reg = SRC,                                 \
 280                 .off   = OFF,                                   \
 281                 .imm   = IMM })
 282
 283 /* Program exit */
 284
 285 #define BPF_EXIT_INSN()                                         \
 286         ((struct bpf_insn) {                                    \
 287                 .code  = BPF_JMP | BPF_EXIT,                    \
 288                 .dst_reg = 0,                                   \
 289                 .src_reg = 0,                                   \
 290                 .off   = 0,                                     \
 291                 .imm   = 0 })
 292
 293 /* Internal classic blocks for direct assignment */
 294
 295 #define __BPF_STMT(CODE, K)                                     \
 296         ((struct sock_filter) BPF_STMT(CODE, K))
 297
 298 #define __BPF_JUMP(CODE, K, JT, JF)                             \
 299         ((struct sock_filter) BPF_JUMP(CODE, K, JT, JF))
 300
 301 #define bytes_to_bpf_size(bytes)                                \
 302 ({                                                              \
 303         int bpf_size = -EINVAL;                                 \
 304                                                                 \
 305         if (bytes == sizeof(u8))                                \
 306                 bpf_size = BPF_B;                               \
 307         else if (bytes == sizeof(u16))                          \
 308                 bpf_size = BPF_H;                               \
 309         else if (bytes == sizeof(u32))                          \
 310                 bpf_size = BPF_W;                               \
 311         else if (bytes == sizeof(u64))                          \
 312                 bpf_size = BPF_DW;                              \
 313                                                                 \
 314         bpf_size;                                               \
 315 })
 316
 317 #ifdef CONFIG_COMPAT
 318 /* A struct sock_filter is architecture independent. */
 319 struct compat_sock_fprog {
 320         u16             len;
 321         compat_uptr_t   filter; /* struct sock_filter * */
 322 };
 323 #endif
 324
 325 struct sock_fprog_kern {
 326         u16                     len;
 327         struct sock_filter      *filter;
 328 };
 329
 330 struct bpf_binary_header {
 331         unsigned int pages;
 332         u8 image[];
 333 };
 334
 335 struct bpf_prog {
 336         u16                     pages;          /* Number of allocated pages */
 337         kmemcheck_bitfield_begin(meta);
 338         u16                     jited:1,        /* Is our filter JIT'ed? */
 339                                 gpl_compatible:1, /* Is filter GPL compatible? */
 340                                 cb_access:1,    /* Is control block accessed? */
 341                                 dst_needed:1;   /* Do we need dst entry? */
 342         kmemcheck_bitfield_end(meta);
 343         u32                     len;            /* Number of filter blocks */
 344         enum bpf_prog_type      type;           /* Type of BPF program */
 345         struct bpf_prog_aux     *aux;           /* Auxiliary fields */
 346         struct sock_fprog_kern  *orig_prog;     /* Original BPF program */
 347         unsigned int            (*bpf_func)(const struct sk_buff *skb,
 348                                             const struct bpf_insn *filter);
 349         /* Instructions for interpreter */
 350         union {
 351                 struct sock_filter      insns[0];
 352                 struct bpf_insn         insnsi[0];
 353         };
 354 };
 355
 356 struct sk_filter {
 357         atomic_t        refcnt;
 358         struct rcu_head rcu;
 359         struct bpf_prog *prog;
 360 };
 361
 362 #define BPF_PROG_RUN(filter, ctx)  (*filter->bpf_func)(ctx, filter->insnsi)
 363
 364 #define BPF_SKB_CB_LEN QDISC_CB_PRIV_LEN
 365
 366 struct bpf_skb_data_end {
 367         struct qdisc_skb_cb qdisc_cb;
 368         void *data_end;
 369 };
 370
 371 /* compute the linear packet data range [data, data_end) which
 372  * will be accessed by cls_bpf and act_bpf programs
 373  */
 374 static inline void bpf_compute_data_end(struct sk_buff *skb)
 375 {
 376         struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb;
 377
 378         BUILD_BUG_ON(sizeof(*cb) > FIELD_SIZEOF(struct sk_buff, cb));
 379         cb->data_end = skb->data + skb_headlen(skb);
 380 }
 381
 382 static inline u8 *bpf_skb_cb(struct sk_buff *skb)
 383 {
 384         /* eBPF programs may read/write skb->cb[] area to transfer meta
 385          * data between tail calls. Since this also needs to work with
 386          * tc, that scratch memory is mapped to qdisc_skb_cb's data area.
 387          *
 388          * In some socket filter cases, the cb unfortunately needs to be
 389          * saved/restored so that protocol specific skb->cb[] data won't
 390          * be lost. In any case, due to unpriviledged eBPF programs
 391          * attached to sockets, we need to clear the bpf_skb_cb() area
 392          * to not leak previous contents to user space.
 393          */
 394         BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) != BPF_SKB_CB_LEN);
 395         BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) !=
 396                      FIELD_SIZEOF(struct qdisc_skb_cb, data));
 397
 398         return qdisc_skb_cb(skb)->data;
 399 }
 400
 401 static inline u32 bpf_prog_run_save_cb(const struct bpf_prog *prog,
 402                                        struct sk_buff *skb)
 403 {
 404         u8 *cb_data = bpf_skb_cb(skb);
 405         u8 cb_saved[BPF_SKB_CB_LEN];
 406         u32 res;
 407
 408         if (unlikely(prog->cb_access)) {
 409                 memcpy(cb_saved, cb_data, sizeof(cb_saved));
 410                 memset(cb_data, 0, sizeof(cb_saved));
 411         }
 412
 413         res = BPF_PROG_RUN(prog, skb);
 414
 415         if (unlikely(prog->cb_access))
 416                 memcpy(cb_data, cb_saved, sizeof(cb_saved));
 417
 418         return res;
 419 }
 420
 421 static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog,
 422                                         struct sk_buff *skb)
 423 {
 424         u8 *cb_data = bpf_skb_cb(skb);
 425
 426         if (unlikely(prog->cb_access))
 427                 memset(cb_data, 0, BPF_SKB_CB_LEN);
 428
 429         return BPF_PROG_RUN(prog, skb);
 430 }
 431
 432 static inline unsigned int bpf_prog_size(unsigned int proglen)
 433 {
 434         return max(sizeof(struct bpf_prog),
 435                    offsetof(struct bpf_prog, insns[proglen]));
 436 }
 437
 438 static inline bool bpf_prog_was_classic(const struct bpf_prog *prog)
 439 {
 440         /* When classic BPF programs have been loaded and the arch
 441          * does not have a classic BPF JIT (anymore), they have been
 442          * converted via bpf_migrate_filter() to eBPF and thus always
 443          * have an unspec program type.
 444          */
 445         return prog->type == BPF_PROG_TYPE_UNSPEC;
 446 }
 447
 448 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
 449
 450 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
 451 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 452 {
 453         set_memory_ro((unsigned long)fp, fp->pages);
 454 }
 455
 456 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 457 {
 458         set_memory_rw((unsigned long)fp, fp->pages);
 459 }
 460 #else
 461 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 462 {
 463 }
 464
 465 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 466 {
 467 }
 468 #endif /* CONFIG_DEBUG_SET_MODULE_RONX */
 469
 470 int sk_filter(struct sock *sk, struct sk_buff *skb);
 471
 472 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err);
 473 void bpf_prog_free(struct bpf_prog *fp);
 474
 475 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
 476 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 477                                   gfp_t gfp_extra_flags);
 478 void __bpf_prog_free(struct bpf_prog *fp);
 479
 480 static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
 481 {
 482         bpf_prog_unlock_ro(fp);
 483         __bpf_prog_free(fp);
 484 }
 485
 486 typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter,
 487                                        unsigned int flen);
 488
 489 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
 490 int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
 491                               bpf_aux_classic_check_t trans, bool save_orig);
 492 void bpf_prog_destroy(struct bpf_prog *fp);
 493
 494 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 495 int sk_attach_bpf(u32 ufd, struct sock *sk);
 496 int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 497 int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk);
 498 int sk_detach_filter(struct sock *sk);
 499 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
 500                   unsigned int len);
 501
 502 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
 503 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
 504
 505 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 506
 507 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog);
 508 bool bpf_helper_changes_skb_data(void *func);
 509
 510 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
 511                                        const struct bpf_insn *patch, u32 len);
 512
 513 #ifdef CONFIG_BPF_JIT
 514 extern int bpf_jit_enable;
 515 extern int bpf_jit_harden;
 516
 517 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
 518
 519 struct bpf_binary_header *
 520 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 521                      unsigned int alignment,
 522                      bpf_jit_fill_hole_t bpf_fill_ill_insns);
 523 void bpf_jit_binary_free(struct bpf_binary_header *hdr);
 524
 525 void bpf_jit_compile(struct bpf_prog *fp);
 526 void bpf_jit_free(struct bpf_prog *fp);
 527
 528 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *fp);
 529 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other);
 530
 531 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
 532                                 u32 pass, void *image)
 533 {
 534         pr_err("flen=%u proglen=%u pass=%u image=%pK from=%s pid=%d\n", flen,
 535                proglen, pass, image, current->comm, task_pid_nr(current));
 536
 537         if (image)
 538                 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
 539                                16, 1, image, proglen, false);
 540 }
 541
 542 static inline bool bpf_jit_is_ebpf(void)
 543 {
 544 # ifdef CONFIG_HAVE_EBPF_JIT
 545         return true;
 546 # else
 547         return false;
 548 # endif
 549 }
 550
 551 static inline bool bpf_jit_blinding_enabled(void)
 552 {
 553         /* These are the prerequisites, should someone ever have the
 554          * idea to call blinding outside of them, we make sure to
 555          * bail out.
 556          */
 557         if (!bpf_jit_is_ebpf())
 558                 return false;
 559         if (!bpf_jit_enable)
 560                 return false;
 561         if (!bpf_jit_harden)
 562                 return false;
 563         if (bpf_jit_harden == 1 && capable(CAP_SYS_ADMIN))
 564                 return false;
 565
 566         return true;
 567 }
 568 #else
 569 static inline void bpf_jit_compile(struct bpf_prog *fp)
 570 {
 571 }
 572
 573 static inline void bpf_jit_free(struct bpf_prog *fp)
 574 {
 575         bpf_prog_unlock_free(fp);
 576 }
 577 #endif /* CONFIG_BPF_JIT */
 578
 579 #define BPF_ANC         BIT(15)
 580
 581 static inline bool bpf_needs_clear_a(const struct sock_filter *first)
 582 {
 583         switch (first->code) {
 584         case BPF_RET | BPF_K:
 585         case BPF_LD | BPF_W | BPF_LEN:
 586                 return false;
 587
 588         case BPF_LD | BPF_W | BPF_ABS:
 589         case BPF_LD | BPF_H | BPF_ABS:
 590         case BPF_LD | BPF_B | BPF_ABS:
 591                 if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
 592                         return true;
 593                 return false;
 594
 595         default:
 596                 return true;
 597         }
 598 }
 599
 600 static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
 601 {
 602         BUG_ON(ftest->code & BPF_ANC);
 603
 604         switch (ftest->code) {
 605         case BPF_LD | BPF_W | BPF_ABS:
 606         case BPF_LD | BPF_H | BPF_ABS:
 607         case BPF_LD | BPF_B | BPF_ABS:
 608 #define BPF_ANCILLARY(CODE)     case SKF_AD_OFF + SKF_AD_##CODE:        \
 609                                 return BPF_ANC | SKF_AD_##CODE
 610                 switch (ftest->k) {
 611                 BPF_ANCILLARY(PROTOCOL);
 612                 BPF_ANCILLARY(PKTTYPE);
 613                 BPF_ANCILLARY(IFINDEX);
 614                 BPF_ANCILLARY(NLATTR);
 615                 BPF_ANCILLARY(NLATTR_NEST);
 616                 BPF_ANCILLARY(MARK);
 617                 BPF_ANCILLARY(QUEUE);
 618                 BPF_ANCILLARY(HATYPE);
 619                 BPF_ANCILLARY(RXHASH);
 620                 BPF_ANCILLARY(CPU);
 621                 BPF_ANCILLARY(ALU_XOR_X);
 622                 BPF_ANCILLARY(VLAN_TAG);
 623                 BPF_ANCILLARY(VLAN_TAG_PRESENT);
 624                 BPF_ANCILLARY(PAY_OFFSET);
 625                 BPF_ANCILLARY(RANDOM);
 626                 BPF_ANCILLARY(VLAN_TPID);
 627                 }
 628                 /* Fallthrough. */
 629         default:
 630                 return ftest->code;
 631         }
 632 }
 633
 634 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
 635                                            int k, unsigned int size);
 636
 637 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
 638                                      unsigned int size, void *buffer)
 639 {
 640         if (k >= 0)
 641                 return skb_header_pointer(skb, k, size, buffer);
 642
 643         return bpf_internal_load_pointer_neg_helper(skb, k, size);
 644 }
 645
 646 static inline int bpf_tell_extensions(void)
 647 {
 648         return SKF_AD_MAX;
 649 }
 650
 651 #endif /* __LINUX_FILTER_H__ */