LXR linux/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
  25struct sk_buff;
  26struct sock;
  27struct seccomp_data;
  28struct 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. */
 319struct compat_sock_fprog {
 320        u16             len;
 321        compat_uptr_t   filter; /* struct sock_filter * */
 322};
 323#endif
 324
 325struct sock_fprog_kern {
 326        u16                     len;
 327        struct sock_filter      *filter;
 328};
 329
 330struct bpf_binary_header {
 331        unsigned int pages;
 332        u8 image[];
 333};
 334
 335struct 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
 356struct 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
 366struct 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 */
 374static 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
 382static 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
 401static 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
 421static 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
 432static 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
 438static 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
 451static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 452{
 453        set_memory_ro((unsigned long)fp, fp->pages);
 454}
 455
 456static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 457{
 458        set_memory_rw((unsigned long)fp, fp->pages);
 459}
 460#else
 461static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 462{
 463}
 464
 465static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 466{
 467}
 468#endif /* CONFIG_DEBUG_SET_MODULE_RONX */
 469
 470int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap);
 471static inline int sk_filter(struct sock *sk, struct sk_buff *skb)
 472{
 473        return sk_filter_trim_cap(sk, skb, 1);
 474}
 475
 476struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err);
 477void bpf_prog_free(struct bpf_prog *fp);
 478
 479struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
 480struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 481                                  gfp_t gfp_extra_flags);
 482void __bpf_prog_free(struct bpf_prog *fp);
 483
 484static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
 485{
 486        bpf_prog_unlock_ro(fp);
 487        __bpf_prog_free(fp);
 488}
 489
 490typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter,
 491                                       unsigned int flen);
 492
 493int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
 494int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
 495                              bpf_aux_classic_check_t trans, bool save_orig);
 496void bpf_prog_destroy(struct bpf_prog *fp);
 497
 498int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 499int sk_attach_bpf(u32 ufd, struct sock *sk);
 500int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 501int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk);
 502int sk_detach_filter(struct sock *sk);
 503int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
 504                  unsigned int len);
 505
 506bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
 507void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
 508
 509u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 510
 511struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog);
 512bool bpf_helper_changes_skb_data(void *func);
 513
 514struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
 515                                       const struct bpf_insn *patch, u32 len);
 516
 517#ifdef CONFIG_BPF_JIT
 518extern int bpf_jit_enable;
 519extern int bpf_jit_harden;
 520
 521typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
 522
 523struct bpf_binary_header *
 524bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 525                     unsigned int alignment,
 526                     bpf_jit_fill_hole_t bpf_fill_ill_insns);
 527void bpf_jit_binary_free(struct bpf_binary_header *hdr);
 528
 529void bpf_jit_compile(struct bpf_prog *fp);
 530void bpf_jit_free(struct bpf_prog *fp);
 531
 532struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *fp);
 533void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other);
 534
 535static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
 536                                u32 pass, void *image)
 537{
 538        pr_err("flen=%u proglen=%u pass=%u image=%pK from=%s pid=%d\n", flen,
 539               proglen, pass, image, current->comm, task_pid_nr(current));
 540
 541        if (image)
 542                print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
 543                               16, 1, image, proglen, false);
 544}
 545
 546static inline bool bpf_jit_is_ebpf(void)
 547{
 548# ifdef CONFIG_HAVE_EBPF_JIT
 549        return true;
 550# else
 551        return false;
 552# endif
 553}
 554
 555static inline bool bpf_jit_blinding_enabled(void)
 556{
 557        /* These are the prerequisites, should someone ever have the
 558         * idea to call blinding outside of them, we make sure to
 559         * bail out.
 560         */
 561        if (!bpf_jit_is_ebpf())
 562                return false;
 563        if (!bpf_jit_enable)
 564                return false;
 565        if (!bpf_jit_harden)
 566                return false;
 567        if (bpf_jit_harden == 1 && capable(CAP_SYS_ADMIN))
 568                return false;
 569
 570        return true;
 571}
 572#else
 573static inline void bpf_jit_compile(struct bpf_prog *fp)
 574{
 575}
 576
 577static inline void bpf_jit_free(struct bpf_prog *fp)
 578{
 579        bpf_prog_unlock_free(fp);
 580}
 581#endif /* CONFIG_BPF_JIT */
 582
 583#define BPF_ANC         BIT(15)
 584
 585static inline bool bpf_needs_clear_a(const struct sock_filter *first)
 586{
 587        switch (first->code) {
 588        case BPF_RET | BPF_K:
 589        case BPF_LD | BPF_W | BPF_LEN:
 590                return false;
 591
 592        case BPF_LD | BPF_W | BPF_ABS:
 593        case BPF_LD | BPF_H | BPF_ABS:
 594        case BPF_LD | BPF_B | BPF_ABS:
 595                if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
 596                        return true;
 597                return false;
 598
 599        default:
 600                return true;
 601        }
 602}
 603
 604static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
 605{
 606        BUG_ON(ftest->code & BPF_ANC);
 607
 608        switch (ftest->code) {
 609        case BPF_LD | BPF_W | BPF_ABS:
 610        case BPF_LD | BPF_H | BPF_ABS:
 611        case BPF_LD | BPF_B | BPF_ABS:
 612#define BPF_ANCILLARY(CODE)     case SKF_AD_OFF + SKF_AD_##CODE:        \
 613                                return BPF_ANC | SKF_AD_##CODE
 614                switch (ftest->k) {
 615                BPF_ANCILLARY(PROTOCOL);
 616                BPF_ANCILLARY(PKTTYPE);
 617                BPF_ANCILLARY(IFINDEX);
 618                BPF_ANCILLARY(NLATTR);
 619                BPF_ANCILLARY(NLATTR_NEST);
 620                BPF_ANCILLARY(MARK);
 621                BPF_ANCILLARY(QUEUE);
 622                BPF_ANCILLARY(HATYPE);
 623                BPF_ANCILLARY(RXHASH);
 624                BPF_ANCILLARY(CPU);
 625                BPF_ANCILLARY(ALU_XOR_X);
 626                BPF_ANCILLARY(VLAN_TAG);
 627                BPF_ANCILLARY(VLAN_TAG_PRESENT);
 628                BPF_ANCILLARY(PAY_OFFSET);
 629                BPF_ANCILLARY(RANDOM);
 630                BPF_ANCILLARY(VLAN_TPID);
 631                }
 632                /* Fallthrough. */
 633        default:
 634                return ftest->code;
 635        }
 636}
 637
 638void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
 639                                           int k, unsigned int size);
 640
 641static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
 642                                     unsigned int size, void *buffer)
 643{
 644        if (k >= 0)
 645                return skb_header_pointer(skb, k, size, buffer);
 646
 647        return bpf_internal_load_pointer_neg_helper(skb, k, size);
 648}
 649
 650static inline int bpf_tell_extensions(void)
 651{
 652        return SKF_AD_MAX;
 653}
 654
 655#endif /* __LINUX_FILTER_H__ */
 656