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 <linux/atomic.h>
   8 #include <linux/compat.h>
   9 #include <linux/skbuff.h>
  10 #include <linux/workqueue.h>
  11 #include <uapi/linux/filter.h>
  12 #include <asm/cacheflush.h>
  13 #include <uapi/linux/bpf.h>
  14
  15 struct sk_buff;
  16 struct sock;
  17 struct seccomp_data;
  18
  19 /* ArgX, context and stack frame pointer register positions. Note,
  20  * Arg1, Arg2, Arg3, etc are used as argument mappings of function
  21  * calls in BPF_CALL instruction.
  22  */
  23 #define BPF_REG_ARG1    BPF_REG_1
  24 #define BPF_REG_ARG2    BPF_REG_2
  25 #define BPF_REG_ARG3    BPF_REG_3
  26 #define BPF_REG_ARG4    BPF_REG_4
  27 #define BPF_REG_ARG5    BPF_REG_5
  28 #define BPF_REG_CTX     BPF_REG_6
  29 #define BPF_REG_FP      BPF_REG_10
  30
  31 /* Additional register mappings for converted user programs. */
  32 #define BPF_REG_A       BPF_REG_0
  33 #define BPF_REG_X       BPF_REG_7
  34 #define BPF_REG_TMP     BPF_REG_8
  35
  36 /* BPF program can access up to 512 bytes of stack space. */
  37 #define MAX_BPF_STACK   512
  38
  39 /* Helper macros for filter block array initializers. */
  40
  41 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
  42
  43 #define BPF_ALU64_REG(OP, DST, SRC)                             \
  44         ((struct bpf_insn) {                                    \
  45                 .code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,        \
  46                 .dst_reg = DST,                                 \
  47                 .src_reg = SRC,                                 \
  48                 .off   = 0,                                     \
  49                 .imm   = 0 })
  50
  51 #define BPF_ALU32_REG(OP, DST, SRC)                             \
  52         ((struct bpf_insn) {                                    \
  53                 .code  = BPF_ALU | BPF_OP(OP) | BPF_X,          \
  54                 .dst_reg = DST,                                 \
  55                 .src_reg = SRC,                                 \
  56                 .off   = 0,                                     \
  57                 .imm   = 0 })
  58
  59 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
  60
  61 #define BPF_ALU64_IMM(OP, DST, IMM)                             \
  62         ((struct bpf_insn) {                                    \
  63                 .code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,        \
  64                 .dst_reg = DST,                                 \
  65                 .src_reg = 0,                                   \
  66                 .off   = 0,                                     \
  67                 .imm   = IMM })
  68
  69 #define BPF_ALU32_IMM(OP, DST, IMM)                             \
  70         ((struct bpf_insn) {                                    \
  71                 .code  = BPF_ALU | BPF_OP(OP) | BPF_K,          \
  72                 .dst_reg = DST,                                 \
  73                 .src_reg = 0,                                   \
  74                 .off   = 0,                                     \
  75                 .imm   = IMM })
  76
  77 /* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
  78
  79 #define BPF_ENDIAN(TYPE, DST, LEN)                              \
  80         ((struct bpf_insn) {                                    \
  81                 .code  = BPF_ALU | BPF_END | BPF_SRC(TYPE),     \
  82                 .dst_reg = DST,                                 \
  83                 .src_reg = 0,                                   \
  84                 .off   = 0,                                     \
  85                 .imm   = LEN })
  86
  87 /* Short form of mov, dst_reg = src_reg */
  88
  89 #define BPF_MOV64_REG(DST, SRC)                                 \
  90         ((struct bpf_insn) {                                    \
  91                 .code  = BPF_ALU64 | BPF_MOV | BPF_X,           \
  92                 .dst_reg = DST,                                 \
  93                 .src_reg = SRC,                                 \
  94                 .off   = 0,                                     \
  95                 .imm   = 0 })
  96
  97 #define BPF_MOV32_REG(DST, SRC)                                 \
  98         ((struct bpf_insn) {                                    \
  99                 .code  = BPF_ALU | BPF_MOV | BPF_X,             \
 100                 .dst_reg = DST,                                 \
 101                 .src_reg = SRC,                                 \
 102                 .off   = 0,                                     \
 103                 .imm   = 0 })
 104
 105 /* Short form of mov, dst_reg = imm32 */
 106
 107 #define BPF_MOV64_IMM(DST, IMM)                                 \
 108         ((struct bpf_insn) {                                    \
 109                 .code  = BPF_ALU64 | BPF_MOV | BPF_K,           \
 110                 .dst_reg = DST,                                 \
 111                 .src_reg = 0,                                   \
 112                 .off   = 0,                                     \
 113                 .imm   = IMM })
 114
 115 #define BPF_MOV32_IMM(DST, IMM)                                 \
 116         ((struct bpf_insn) {                                    \
 117                 .code  = BPF_ALU | BPF_MOV | BPF_K,             \
 118                 .dst_reg = DST,                                 \
 119                 .src_reg = 0,                                   \
 120                 .off   = 0,                                     \
 121                 .imm   = IMM })
 122
 123 /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
 124 #define BPF_LD_IMM64(DST, IMM)                                  \
 125         BPF_LD_IMM64_RAW(DST, 0, IMM)
 126
 127 #define BPF_LD_IMM64_RAW(DST, SRC, IMM)                         \
 128         ((struct bpf_insn) {                                    \
 129                 .code  = BPF_LD | BPF_DW | BPF_IMM,             \
 130                 .dst_reg = DST,                                 \
 131                 .src_reg = SRC,                                 \
 132                 .off   = 0,                                     \
 133                 .imm   = (__u32) (IMM) }),                      \
 134         ((struct bpf_insn) {                                    \
 135                 .code  = 0, /* zero is reserved opcode */       \
 136                 .dst_reg = 0,                                   \
 137                 .src_reg = 0,                                   \
 138                 .off   = 0,                                     \
 139                 .imm   = ((__u64) (IMM)) >> 32 })
 140
 141 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
 142
 143 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM)                      \
 144         ((struct bpf_insn) {                                    \
 145                 .code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),   \
 146                 .dst_reg = DST,                                 \
 147                 .src_reg = SRC,                                 \
 148                 .off   = 0,                                     \
 149                 .imm   = IMM })
 150
 151 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM)                      \
 152         ((struct bpf_insn) {                                    \
 153                 .code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),     \
 154                 .dst_reg = DST,                                 \
 155                 .src_reg = SRC,                                 \
 156                 .off   = 0,                                     \
 157                 .imm   = IMM })
 158
 159 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
 160
 161 #define BPF_LD_ABS(SIZE, IMM)                                   \
 162         ((struct bpf_insn) {                                    \
 163                 .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,     \
 164                 .dst_reg = 0,                                   \
 165                 .src_reg = 0,                                   \
 166                 .off   = 0,                                     \
 167                 .imm   = IMM })
 168
 169 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
 170
 171 #define BPF_LD_IND(SIZE, SRC, IMM)                              \
 172         ((struct bpf_insn) {                                    \
 173                 .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,     \
 174                 .dst_reg = 0,                                   \
 175                 .src_reg = SRC,                                 \
 176                 .off   = 0,                                     \
 177                 .imm   = IMM })
 178
 179 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */
 180
 181 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF)                        \
 182         ((struct bpf_insn) {                                    \
 183                 .code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,    \
 184                 .dst_reg = DST,                                 \
 185                 .src_reg = SRC,                                 \
 186                 .off   = OFF,                                   \
 187                 .imm   = 0 })
 188
 189 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */
 190
 191 #define BPF_STX_MEM(SIZE, DST, SRC, OFF)                        \
 192         ((struct bpf_insn) {                                    \
 193                 .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,    \
 194                 .dst_reg = DST,                                 \
 195                 .src_reg = SRC,                                 \
 196                 .off   = OFF,                                   \
 197                 .imm   = 0 })
 198
 199 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
 200
 201 #define BPF_ST_MEM(SIZE, DST, OFF, IMM)                         \
 202         ((struct bpf_insn) {                                    \
 203                 .code  = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM,     \
 204                 .dst_reg = DST,                                 \
 205                 .src_reg = 0,                                   \
 206                 .off   = OFF,                                   \
 207                 .imm   = IMM })
 208
 209 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
 210
 211 #define BPF_JMP_REG(OP, DST, SRC, OFF)                          \
 212         ((struct bpf_insn) {                                    \
 213                 .code  = BPF_JMP | BPF_OP(OP) | BPF_X,          \
 214                 .dst_reg = DST,                                 \
 215                 .src_reg = SRC,                                 \
 216                 .off   = OFF,                                   \
 217                 .imm   = 0 })
 218
 219 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
 220
 221 #define BPF_JMP_IMM(OP, DST, IMM, OFF)                          \
 222         ((struct bpf_insn) {                                    \
 223                 .code  = BPF_JMP | BPF_OP(OP) | BPF_K,          \
 224                 .dst_reg = DST,                                 \
 225                 .src_reg = 0,                                   \
 226                 .off   = OFF,                                   \
 227                 .imm   = IMM })
 228
 229 /* Function call */
 230
 231 #define BPF_EMIT_CALL(FUNC)                                     \
 232         ((struct bpf_insn) {                                    \
 233                 .code  = BPF_JMP | BPF_CALL,                    \
 234                 .dst_reg = 0,                                   \
 235                 .src_reg = 0,                                   \
 236                 .off   = 0,                                     \
 237                 .imm   = ((FUNC) - __bpf_call_base) })
 238
 239 /* Raw code statement block */
 240
 241 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM)                  \
 242         ((struct bpf_insn) {                                    \
 243                 .code  = CODE,                                  \
 244                 .dst_reg = DST,                                 \
 245                 .src_reg = SRC,                                 \
 246                 .off   = OFF,                                   \
 247                 .imm   = IMM })
 248
 249 /* Program exit */
 250
 251 #define BPF_EXIT_INSN()                                         \
 252         ((struct bpf_insn) {                                    \
 253                 .code  = BPF_JMP | BPF_EXIT,                    \
 254                 .dst_reg = 0,                                   \
 255                 .src_reg = 0,                                   \
 256                 .off   = 0,                                     \
 257                 .imm   = 0 })
 258
 259 #define bytes_to_bpf_size(bytes)                                \
 260 ({                                                              \
 261         int bpf_size = -EINVAL;                                 \
 262                                                                 \
 263         if (bytes == sizeof(u8))                                \
 264                 bpf_size = BPF_B;                               \
 265         else if (bytes == sizeof(u16))                          \
 266                 bpf_size = BPF_H;                               \
 267         else if (bytes == sizeof(u32))                          \
 268                 bpf_size = BPF_W;                               \
 269         else if (bytes == sizeof(u64))                          \
 270                 bpf_size = BPF_DW;                              \
 271                                                                 \
 272         bpf_size;                                               \
 273 })
 274
 275 /* Macro to invoke filter function. */
 276 #define SK_RUN_FILTER(filter, ctx) \
 277         (*filter->prog->bpf_func)(ctx, filter->prog->insnsi)
 278
 279 #ifdef CONFIG_COMPAT
 280 /* A struct sock_filter is architecture independent. */
 281 struct compat_sock_fprog {
 282         u16             len;
 283         compat_uptr_t   filter; /* struct sock_filter * */
 284 };
 285 #endif
 286
 287 struct sock_fprog_kern {
 288         u16                     len;
 289         struct sock_filter      *filter;
 290 };
 291
 292 struct bpf_binary_header {
 293         unsigned int pages;
 294         u8 image[];
 295 };
 296
 297 struct bpf_work_struct {
 298         struct bpf_prog *prog;
 299         struct work_struct work;
 300 };
 301
 302 struct bpf_prog {
 303         u16                     pages;          /* Number of allocated pages */
 304         bool                    jited;          /* Is our filter JIT'ed? */
 305         u32                     len;            /* Number of filter blocks */
 306         struct sock_fprog_kern  *orig_prog;     /* Original BPF program */
 307         struct bpf_work_struct  *work;          /* Deferred free work struct */
 308         unsigned int            (*bpf_func)(const struct sk_buff *skb,
 309                                             const struct bpf_insn *filter);
 310         /* Instructions for interpreter */
 311         union {
 312                 struct sock_filter      insns[0];
 313                 struct bpf_insn         insnsi[0];
 314         };
 315 };
 316
 317 struct sk_filter {
 318         atomic_t        refcnt;
 319         struct rcu_head rcu;
 320         struct bpf_prog *prog;
 321 };
 322
 323 #define BPF_PROG_RUN(filter, ctx)  (*filter->bpf_func)(ctx, filter->insnsi)
 324
 325 static inline unsigned int bpf_prog_size(unsigned int proglen)
 326 {
 327         return max(sizeof(struct bpf_prog),
 328                    offsetof(struct bpf_prog, insns[proglen]));
 329 }
 330
 331 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
 332
 333 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
 334 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 335 {
 336         set_memory_ro((unsigned long)fp, fp->pages);
 337 }
 338
 339 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 340 {
 341         set_memory_rw((unsigned long)fp, fp->pages);
 342 }
 343 #else
 344 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 345 {
 346 }
 347
 348 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 349 {
 350 }
 351 #endif /* CONFIG_DEBUG_SET_MODULE_RONX */
 352
 353 int sk_filter(struct sock *sk, struct sk_buff *skb);
 354
 355 void bpf_prog_select_runtime(struct bpf_prog *fp);
 356 void bpf_prog_free(struct bpf_prog *fp);
 357
 358 int bpf_convert_filter(struct sock_filter *prog, int len,
 359                        struct bpf_insn *new_prog, int *new_len);
 360
 361 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
 362 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 363                                   gfp_t gfp_extra_flags);
 364 void __bpf_prog_free(struct bpf_prog *fp);
 365
 366 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
 367
 368 struct bpf_binary_header *
 369 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 370                      unsigned int alignment,
 371                      bpf_jit_fill_hole_t bpf_fill_ill_insns);
 372 void bpf_jit_binary_free(struct bpf_binary_header *hdr);
 373
 374 static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
 375 {
 376         bpf_prog_unlock_ro(fp);
 377         __bpf_prog_free(fp);
 378 }
 379
 380 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
 381 void bpf_prog_destroy(struct bpf_prog *fp);
 382
 383 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 384 int sk_detach_filter(struct sock *sk);
 385
 386 int bpf_check_classic(const struct sock_filter *filter, unsigned int flen);
 387 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
 388                   unsigned int len);
 389
 390 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
 391 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
 392
 393 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 394 void bpf_int_jit_compile(struct bpf_prog *fp);
 395
 396 #define BPF_ANC         BIT(15)
 397
 398 static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
 399 {
 400         BUG_ON(ftest->code & BPF_ANC);
 401
 402         switch (ftest->code) {
 403         case BPF_LD | BPF_W | BPF_ABS:
 404         case BPF_LD | BPF_H | BPF_ABS:
 405         case BPF_LD | BPF_B | BPF_ABS:
 406 #define BPF_ANCILLARY(CODE)     case SKF_AD_OFF + SKF_AD_##CODE:        \
 407                                 return BPF_ANC | SKF_AD_##CODE
 408                 switch (ftest->k) {
 409                 BPF_ANCILLARY(PROTOCOL);
 410                 BPF_ANCILLARY(PKTTYPE);
 411                 BPF_ANCILLARY(IFINDEX);
 412                 BPF_ANCILLARY(NLATTR);
 413                 BPF_ANCILLARY(NLATTR_NEST);
 414                 BPF_ANCILLARY(MARK);
 415                 BPF_ANCILLARY(QUEUE);
 416                 BPF_ANCILLARY(HATYPE);
 417                 BPF_ANCILLARY(RXHASH);
 418                 BPF_ANCILLARY(CPU);
 419                 BPF_ANCILLARY(ALU_XOR_X);
 420                 BPF_ANCILLARY(VLAN_TAG);
 421                 BPF_ANCILLARY(VLAN_TAG_PRESENT);
 422                 BPF_ANCILLARY(PAY_OFFSET);
 423                 BPF_ANCILLARY(RANDOM);
 424                 }
 425                 /* Fallthrough. */
 426         default:
 427                 return ftest->code;
 428         }
 429 }
 430
 431 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
 432                                            int k, unsigned int size);
 433
 434 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
 435                                      unsigned int size, void *buffer)
 436 {
 437         if (k >= 0)
 438                 return skb_header_pointer(skb, k, size, buffer);
 439
 440         return bpf_internal_load_pointer_neg_helper(skb, k, size);
 441 }
 442
 443 #ifdef CONFIG_BPF_JIT
 444 #include <stdarg.h>
 445 #include <linux/linkage.h>
 446 #include <linux/printk.h>
 447
 448 void bpf_jit_compile(struct bpf_prog *fp);
 449 void bpf_jit_free(struct bpf_prog *fp);
 450
 451 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
 452                                 u32 pass, void *image)
 453 {
 454         pr_err("flen=%u proglen=%u pass=%u image=%pK\n",
 455                flen, proglen, pass, image);
 456         if (image)
 457                 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
 458                                16, 1, image, proglen, false);
 459 }
 460 #else
 461 #include <linux/slab.h>
 462
 463 static inline void bpf_jit_compile(struct bpf_prog *fp)
 464 {
 465 }
 466
 467 static inline void bpf_jit_free(struct bpf_prog *fp)
 468 {
 469         bpf_prog_unlock_free(fp);
 470 }
 471 #endif /* CONFIG_BPF_JIT */
 472
 473 static inline int bpf_tell_extensions(void)
 474 {
 475         return SKF_AD_MAX;
 476 }
 477
 478 #endif /* __LINUX_FILTER_H__ */