include/linux/filter.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Linux Socket Filter Data Structures
   4  */
   5 #ifndef __LINUX_FILTER_H__
   6 #define __LINUX_FILTER_H__
   7
   8 #include <stdarg.h>
   9
  10 #include <linux/atomic.h>
  11 #include <linux/refcount.h>
  12 #include <linux/compat.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/linkage.h>
  15 #include <linux/printk.h>
  16 #include <linux/workqueue.h>
  17 #include <linux/sched.h>
  18 #include <linux/capability.h>
  19 #include <linux/cryptohash.h>
  20 #include <linux/set_memory.h>
  21 #include <linux/kallsyms.h>
  22
  23 #include <net/xdp.h>
  24 #include <net/sch_generic.h>
  25
  26 #include <uapi/linux/filter.h>
  27 #include <uapi/linux/bpf.h>
  28
  29 struct sk_buff;
  30 struct sock;
  31 struct seccomp_data;
  32 struct bpf_prog_aux;
  33
  34 /* ArgX, context and stack frame pointer register positions. Note,
  35  * Arg1, Arg2, Arg3, etc are used as argument mappings of function
  36  * calls in BPF_CALL instruction.
  37  */
  38 #define BPF_REG_ARG1    BPF_REG_1
  39 #define BPF_REG_ARG2    BPF_REG_2
  40 #define BPF_REG_ARG3    BPF_REG_3
  41 #define BPF_REG_ARG4    BPF_REG_4
  42 #define BPF_REG_ARG5    BPF_REG_5
  43 #define BPF_REG_CTX     BPF_REG_6
  44 #define BPF_REG_FP      BPF_REG_10
  45
  46 /* Additional register mappings for converted user programs. */
  47 #define BPF_REG_A       BPF_REG_0
  48 #define BPF_REG_X       BPF_REG_7
  49 #define BPF_REG_TMP     BPF_REG_8
  50
  51 /* Kernel hidden auxiliary/helper register for hardening step.
  52  * Only used by eBPF JITs. It's nothing more than a temporary
  53  * register that JITs use internally, only that here it's part
  54  * of eBPF instructions that have been rewritten for blinding
  55  * constants. See JIT pre-step in bpf_jit_blind_constants().
  56  */
  57 #define BPF_REG_AX              MAX_BPF_REG
  58 #define MAX_BPF_JIT_REG         (MAX_BPF_REG + 1)
  59
  60 /* unused opcode to mark special call to bpf_tail_call() helper */
  61 #define BPF_TAIL_CALL   0xf0
  62
  63 /* unused opcode to mark call to interpreter with arguments */
  64 #define BPF_CALL_ARGS   0xe0
  65
  66 /* As per nm, we expose JITed images as text (code) section for
  67  * kallsyms. That way, tools like perf can find it to match
  68  * addresses.
  69  */
  70 #define BPF_SYM_ELF_TYPE        't'
  71
  72 /* BPF program can access up to 512 bytes of stack space. */
  73 #define MAX_BPF_STACK   512
  74
  75 /* Helper macros for filter block array initializers. */
  76
  77 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
  78
  79 #define BPF_ALU64_REG(OP, DST, SRC)                             \
  80         ((struct bpf_insn) {                                    \
  81                 .code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,        \
  82                 .dst_reg = DST,                                 \
  83                 .src_reg = SRC,                                 \
  84                 .off   = 0,                                     \
  85                 .imm   = 0 })
  86
  87 #define BPF_ALU32_REG(OP, DST, SRC)                             \
  88         ((struct bpf_insn) {                                    \
  89                 .code  = BPF_ALU | BPF_OP(OP) | BPF_X,          \
  90                 .dst_reg = DST,                                 \
  91                 .src_reg = SRC,                                 \
  92                 .off   = 0,                                     \
  93                 .imm   = 0 })
  94
  95 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
  96
  97 #define BPF_ALU64_IMM(OP, DST, IMM)                             \
  98         ((struct bpf_insn) {                                    \
  99                 .code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,        \
 100                 .dst_reg = DST,                                 \
 101                 .src_reg = 0,                                   \
 102                 .off   = 0,                                     \
 103                 .imm   = IMM })
 104
 105 #define BPF_ALU32_IMM(OP, DST, IMM)                             \
 106         ((struct bpf_insn) {                                    \
 107                 .code  = BPF_ALU | BPF_OP(OP) | BPF_K,          \
 108                 .dst_reg = DST,                                 \
 109                 .src_reg = 0,                                   \
 110                 .off   = 0,                                     \
 111                 .imm   = IMM })
 112
 113 /* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
 114
 115 #define BPF_ENDIAN(TYPE, DST, LEN)                              \
 116         ((struct bpf_insn) {                                    \
 117                 .code  = BPF_ALU | BPF_END | BPF_SRC(TYPE),     \
 118                 .dst_reg = DST,                                 \
 119                 .src_reg = 0,                                   \
 120                 .off   = 0,                                     \
 121                 .imm   = LEN })
 122
 123 /* Short form of mov, dst_reg = src_reg */
 124
 125 #define BPF_MOV64_REG(DST, SRC)                                 \
 126         ((struct bpf_insn) {                                    \
 127                 .code  = BPF_ALU64 | BPF_MOV | BPF_X,           \
 128                 .dst_reg = DST,                                 \
 129                 .src_reg = SRC,                                 \
 130                 .off   = 0,                                     \
 131                 .imm   = 0 })
 132
 133 #define BPF_MOV32_REG(DST, SRC)                                 \
 134         ((struct bpf_insn) {                                    \
 135                 .code  = BPF_ALU | BPF_MOV | BPF_X,             \
 136                 .dst_reg = DST,                                 \
 137                 .src_reg = SRC,                                 \
 138                 .off   = 0,                                     \
 139                 .imm   = 0 })
 140
 141 /* Short form of mov, dst_reg = imm32 */
 142
 143 #define BPF_MOV64_IMM(DST, IMM)                                 \
 144         ((struct bpf_insn) {                                    \
 145                 .code  = BPF_ALU64 | BPF_MOV | BPF_K,           \
 146                 .dst_reg = DST,                                 \
 147                 .src_reg = 0,                                   \
 148                 .off   = 0,                                     \
 149                 .imm   = IMM })
 150
 151 #define BPF_MOV32_IMM(DST, IMM)                                 \
 152         ((struct bpf_insn) {                                    \
 153                 .code  = BPF_ALU | BPF_MOV | BPF_K,             \
 154                 .dst_reg = DST,                                 \
 155                 .src_reg = 0,                                   \
 156                 .off   = 0,                                     \
 157                 .imm   = IMM })
 158
 159 /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
 160 #define BPF_LD_IMM64(DST, IMM)                                  \
 161         BPF_LD_IMM64_RAW(DST, 0, IMM)
 162
 163 #define BPF_LD_IMM64_RAW(DST, SRC, IMM)                         \
 164         ((struct bpf_insn) {                                    \
 165                 .code  = BPF_LD | BPF_DW | BPF_IMM,             \
 166                 .dst_reg = DST,                                 \
 167                 .src_reg = SRC,                                 \
 168                 .off   = 0,                                     \
 169                 .imm   = (__u32) (IMM) }),                      \
 170         ((struct bpf_insn) {                                    \
 171                 .code  = 0, /* zero is reserved opcode */       \
 172                 .dst_reg = 0,                                   \
 173                 .src_reg = 0,                                   \
 174                 .off   = 0,                                     \
 175                 .imm   = ((__u64) (IMM)) >> 32 })
 176
 177 /* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
 178 #define BPF_LD_MAP_FD(DST, MAP_FD)                              \
 179         BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
 180
 181 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
 182
 183 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM)                      \
 184         ((struct bpf_insn) {                                    \
 185                 .code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),   \
 186                 .dst_reg = DST,                                 \
 187                 .src_reg = SRC,                                 \
 188                 .off   = 0,                                     \
 189                 .imm   = IMM })
 190
 191 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM)                      \
 192         ((struct bpf_insn) {                                    \
 193                 .code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),     \
 194                 .dst_reg = DST,                                 \
 195                 .src_reg = SRC,                                 \
 196                 .off   = 0,                                     \
 197                 .imm   = IMM })
 198
 199 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
 200
 201 #define BPF_LD_ABS(SIZE, IMM)                                   \
 202         ((struct bpf_insn) {                                    \
 203                 .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,     \
 204                 .dst_reg = 0,                                   \
 205                 .src_reg = 0,                                   \
 206                 .off   = 0,                                     \
 207                 .imm   = IMM })
 208
 209 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
 210
 211 #define BPF_LD_IND(SIZE, SRC, IMM)                              \
 212         ((struct bpf_insn) {                                    \
 213                 .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,     \
 214                 .dst_reg = 0,                                   \
 215                 .src_reg = SRC,                                 \
 216                 .off   = 0,                                     \
 217                 .imm   = IMM })
 218
 219 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */
 220
 221 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF)                        \
 222         ((struct bpf_insn) {                                    \
 223                 .code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,    \
 224                 .dst_reg = DST,                                 \
 225                 .src_reg = SRC,                                 \
 226                 .off   = OFF,                                   \
 227                 .imm   = 0 })
 228
 229 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */
 230
 231 #define BPF_STX_MEM(SIZE, DST, SRC, OFF)                        \
 232         ((struct bpf_insn) {                                    \
 233                 .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,    \
 234                 .dst_reg = DST,                                 \
 235                 .src_reg = SRC,                                 \
 236                 .off   = OFF,                                   \
 237                 .imm   = 0 })
 238
 239 /* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */
 240
 241 #define BPF_STX_XADD(SIZE, DST, SRC, OFF)                       \
 242         ((struct bpf_insn) {                                    \
 243                 .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD,   \
 244                 .dst_reg = DST,                                 \
 245                 .src_reg = SRC,                                 \
 246                 .off   = OFF,                                   \
 247                 .imm   = 0 })
 248
 249 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
 250
 251 #define BPF_ST_MEM(SIZE, DST, OFF, IMM)                         \
 252         ((struct bpf_insn) {                                    \
 253                 .code  = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM,     \
 254                 .dst_reg = DST,                                 \
 255                 .src_reg = 0,                                   \
 256                 .off   = OFF,                                   \
 257                 .imm   = IMM })
 258
 259 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
 260
 261 #define BPF_JMP_REG(OP, DST, SRC, OFF)                          \
 262         ((struct bpf_insn) {                                    \
 263                 .code  = BPF_JMP | BPF_OP(OP) | BPF_X,          \
 264                 .dst_reg = DST,                                 \
 265                 .src_reg = SRC,                                 \
 266                 .off   = OFF,                                   \
 267                 .imm   = 0 })
 268
 269 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
 270
 271 #define BPF_JMP_IMM(OP, DST, IMM, OFF)                          \
 272         ((struct bpf_insn) {                                    \
 273                 .code  = BPF_JMP | BPF_OP(OP) | BPF_K,          \
 274                 .dst_reg = DST,                                 \
 275                 .src_reg = 0,                                   \
 276                 .off   = OFF,                                   \
 277                 .imm   = IMM })
 278
 279 /* Unconditional jumps, goto pc + off16 */
 280
 281 #define BPF_JMP_A(OFF)                                          \
 282         ((struct bpf_insn) {                                    \
 283                 .code  = BPF_JMP | BPF_JA,                      \
 284                 .dst_reg = 0,                                   \
 285                 .src_reg = 0,                                   \
 286                 .off   = OFF,                                   \
 287                 .imm   = 0 })
 288
 289 /* Function call */
 290
 291 #define BPF_EMIT_CALL(FUNC)                                     \
 292         ((struct bpf_insn) {                                    \
 293                 .code  = BPF_JMP | BPF_CALL,                    \
 294                 .dst_reg = 0,                                   \
 295                 .src_reg = 0,                                   \
 296                 .off   = 0,                                     \
 297                 .imm   = ((FUNC) - __bpf_call_base) })
 298
 299 /* Raw code statement block */
 300
 301 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM)                  \
 302         ((struct bpf_insn) {                                    \
 303                 .code  = CODE,                                  \
 304                 .dst_reg = DST,                                 \
 305                 .src_reg = SRC,                                 \
 306                 .off   = OFF,                                   \
 307                 .imm   = IMM })
 308
 309 /* Program exit */
 310
 311 #define BPF_EXIT_INSN()                                         \
 312         ((struct bpf_insn) {                                    \
 313                 .code  = BPF_JMP | BPF_EXIT,                    \
 314                 .dst_reg = 0,                                   \
 315                 .src_reg = 0,                                   \
 316                 .off   = 0,                                     \
 317                 .imm   = 0 })
 318
 319 /* Internal classic blocks for direct assignment */
 320
 321 #define __BPF_STMT(CODE, K)                                     \
 322         ((struct sock_filter) BPF_STMT(CODE, K))
 323
 324 #define __BPF_JUMP(CODE, K, JT, JF)                             \
 325         ((struct sock_filter) BPF_JUMP(CODE, K, JT, JF))
 326
 327 #define bytes_to_bpf_size(bytes)                                \
 328 ({                                                              \
 329         int bpf_size = -EINVAL;                                 \
 330                                                                 \
 331         if (bytes == sizeof(u8))                                \
 332                 bpf_size = BPF_B;                               \
 333         else if (bytes == sizeof(u16))                          \
 334                 bpf_size = BPF_H;                               \
 335         else if (bytes == sizeof(u32))                          \
 336                 bpf_size = BPF_W;                               \
 337         else if (bytes == sizeof(u64))                          \
 338                 bpf_size = BPF_DW;                              \
 339                                                                 \
 340         bpf_size;                                               \
 341 })
 342
 343 #define bpf_size_to_bytes(bpf_size)                             \
 344 ({                                                              \
 345         int bytes = -EINVAL;                                    \
 346                                                                 \
 347         if (bpf_size == BPF_B)                                  \
 348                 bytes = sizeof(u8);                             \
 349         else if (bpf_size == BPF_H)                             \
 350                 bytes = sizeof(u16);                            \
 351         else if (bpf_size == BPF_W)                             \
 352                 bytes = sizeof(u32);                            \
 353         else if (bpf_size == BPF_DW)                            \
 354                 bytes = sizeof(u64);                            \
 355                                                                 \
 356         bytes;                                                  \
 357 })
 358
 359 #define BPF_SIZEOF(type)                                        \
 360         ({                                                      \
 361                 const int __size = bytes_to_bpf_size(sizeof(type)); \
 362                 BUILD_BUG_ON(__size < 0);                       \
 363                 __size;                                         \
 364         })
 365
 366 #define BPF_FIELD_SIZEOF(type, field)                           \
 367         ({                                                      \
 368                 const int __size = bytes_to_bpf_size(FIELD_SIZEOF(type, field)); \
 369                 BUILD_BUG_ON(__size < 0);                       \
 370                 __size;                                         \
 371         })
 372
 373 #define BPF_LDST_BYTES(insn)                                    \
 374         ({                                                      \
 375                 const int __size = bpf_size_to_bytes(BPF_SIZE(insn->code)); \
 376                 WARN_ON(__size < 0);                            \
 377                 __size;                                         \
 378         })
 379
 380 #define __BPF_MAP_0(m, v, ...) v
 381 #define __BPF_MAP_1(m, v, t, a, ...) m(t, a)
 382 #define __BPF_MAP_2(m, v, t, a, ...) m(t, a), __BPF_MAP_1(m, v, __VA_ARGS__)
 383 #define __BPF_MAP_3(m, v, t, a, ...) m(t, a), __BPF_MAP_2(m, v, __VA_ARGS__)
 384 #define __BPF_MAP_4(m, v, t, a, ...) m(t, a), __BPF_MAP_3(m, v, __VA_ARGS__)
 385 #define __BPF_MAP_5(m, v, t, a, ...) m(t, a), __BPF_MAP_4(m, v, __VA_ARGS__)
 386
 387 #define __BPF_REG_0(...) __BPF_PAD(5)
 388 #define __BPF_REG_1(...) __BPF_MAP(1, __VA_ARGS__), __BPF_PAD(4)
 389 #define __BPF_REG_2(...) __BPF_MAP(2, __VA_ARGS__), __BPF_PAD(3)
 390 #define __BPF_REG_3(...) __BPF_MAP(3, __VA_ARGS__), __BPF_PAD(2)
 391 #define __BPF_REG_4(...) __BPF_MAP(4, __VA_ARGS__), __BPF_PAD(1)
 392 #define __BPF_REG_5(...) __BPF_MAP(5, __VA_ARGS__)
 393
 394 #define __BPF_MAP(n, ...) __BPF_MAP_##n(__VA_ARGS__)
 395 #define __BPF_REG(n, ...) __BPF_REG_##n(__VA_ARGS__)
 396
 397 #define __BPF_CAST(t, a)                                                       \
 398         (__force t)                                                            \
 399         (__force                                                               \
 400          typeof(__builtin_choose_expr(sizeof(t) == sizeof(unsigned long),      \
 401                                       (unsigned long)0, (t)0))) a
 402 #define __BPF_V void
 403 #define __BPF_N
 404
 405 #define __BPF_DECL_ARGS(t, a) t   a
 406 #define __BPF_DECL_REGS(t, a) u64 a
 407
 408 #define __BPF_PAD(n)                                                           \
 409         __BPF_MAP(n, __BPF_DECL_ARGS, __BPF_N, u64, __ur_1, u64, __ur_2,       \
 410                   u64, __ur_3, u64, __ur_4, u64, __ur_5)
 411
 412 #define BPF_CALL_x(x, name, ...)                                               \
 413         static __always_inline                                                 \
 414         u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__));   \
 415         u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__));         \
 416         u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__))          \
 417         {                                                                      \
 418                 return ____##name(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\
 419         }                                                                      \
 420         static __always_inline                                                 \
 421         u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__))
 422
 423 #define BPF_CALL_0(name, ...)   BPF_CALL_x(0, name, __VA_ARGS__)
 424 #define BPF_CALL_1(name, ...)   BPF_CALL_x(1, name, __VA_ARGS__)
 425 #define BPF_CALL_2(name, ...)   BPF_CALL_x(2, name, __VA_ARGS__)
 426 #define BPF_CALL_3(name, ...)   BPF_CALL_x(3, name, __VA_ARGS__)
 427 #define BPF_CALL_4(name, ...)   BPF_CALL_x(4, name, __VA_ARGS__)
 428 #define BPF_CALL_5(name, ...)   BPF_CALL_x(5, name, __VA_ARGS__)
 429
 430 #define bpf_ctx_range(TYPE, MEMBER)                                             \
 431         offsetof(TYPE, MEMBER) ... offsetofend(TYPE, MEMBER) - 1
 432 #define bpf_ctx_range_till(TYPE, MEMBER1, MEMBER2)                              \
 433         offsetof(TYPE, MEMBER1) ... offsetofend(TYPE, MEMBER2) - 1
 434
 435 #define bpf_target_off(TYPE, MEMBER, SIZE, PTR_SIZE)                            \
 436         ({                                                                      \
 437                 BUILD_BUG_ON(FIELD_SIZEOF(TYPE, MEMBER) != (SIZE));             \
 438                 *(PTR_SIZE) = (SIZE);                                           \
 439                 offsetof(TYPE, MEMBER);                                         \
 440         })
 441
 442 #ifdef CONFIG_COMPAT
 443 /* A struct sock_filter is architecture independent. */
 444 struct compat_sock_fprog {
 445         u16             len;
 446         compat_uptr_t   filter; /* struct sock_filter * */
 447 };
 448 #endif
 449
 450 struct sock_fprog_kern {
 451         u16                     len;
 452         struct sock_filter      *filter;
 453 };
 454
 455 struct bpf_binary_header {
 456         unsigned int pages;
 457         u8 image[];
 458 };
 459
 460 struct bpf_prog {
 461         u16                     pages;          /* Number of allocated pages */
 462         u16                     jited:1,        /* Is our filter JIT'ed? */
 463                                 jit_requested:1,/* archs need to JIT the prog */
 464                                 locked:1,       /* Program image locked? */
 465                                 gpl_compatible:1, /* Is filter GPL compatible? */
 466                                 cb_access:1,    /* Is control block accessed? */
 467                                 dst_needed:1,   /* Do we need dst entry? */
 468                                 blinded:1,      /* Was blinded */
 469                                 is_func:1,      /* program is a bpf function */
 470                                 kprobe_override:1; /* Do we override a kprobe? */
 471         enum bpf_prog_type      type;           /* Type of BPF program */
 472         u32                     len;            /* Number of filter blocks */
 473         u32                     jited_len;      /* Size of jited insns in bytes */
 474         u8                      tag[BPF_TAG_SIZE];
 475         struct bpf_prog_aux     *aux;           /* Auxiliary fields */
 476         struct sock_fprog_kern  *orig_prog;     /* Original BPF program */
 477         unsigned int            (*bpf_func)(const void *ctx,
 478                                             const struct bpf_insn *insn);
 479         /* Instructions for interpreter */
 480         union {
 481                 struct sock_filter      insns[0];
 482                 struct bpf_insn         insnsi[0];
 483         };
 484 };
 485
 486 struct sk_filter {
 487         refcount_t      refcnt;
 488         struct rcu_head rcu;
 489         struct bpf_prog *prog;
 490 };
 491
 492 #define BPF_PROG_RUN(filter, ctx)  (*(filter)->bpf_func)(ctx, (filter)->insnsi)
 493
 494 #define BPF_SKB_CB_LEN QDISC_CB_PRIV_LEN
 495
 496 struct bpf_skb_data_end {
 497         struct qdisc_skb_cb qdisc_cb;
 498         void *data_meta;
 499         void *data_end;
 500 };
 501
 502 struct xdp_buff {
 503         void *data;
 504         void *data_end;
 505         void *data_meta;
 506         void *data_hard_start;
 507         struct xdp_rxq_info *rxq;
 508 };
 509
 510 /* Compute the linear packet data range [data, data_end) which
 511  * will be accessed by various program types (cls_bpf, act_bpf,
 512  * lwt, ...). Subsystems allowing direct data access must (!)
 513  * ensure that cb[] area can be written to when BPF program is
 514  * invoked (otherwise cb[] save/restore is necessary).
 515  */
 516 static inline void bpf_compute_data_pointers(struct sk_buff *skb)
 517 {
 518         struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb;
 519
 520         BUILD_BUG_ON(sizeof(*cb) > FIELD_SIZEOF(struct sk_buff, cb));
 521         cb->data_meta = skb->data - skb_metadata_len(skb);
 522         cb->data_end  = skb->data + skb_headlen(skb);
 523 }
 524
 525 static inline u8 *bpf_skb_cb(struct sk_buff *skb)
 526 {
 527         /* eBPF programs may read/write skb->cb[] area to transfer meta
 528          * data between tail calls. Since this also needs to work with
 529          * tc, that scratch memory is mapped to qdisc_skb_cb's data area.
 530          *
 531          * In some socket filter cases, the cb unfortunately needs to be
 532          * saved/restored so that protocol specific skb->cb[] data won't
 533          * be lost. In any case, due to unpriviledged eBPF programs
 534          * attached to sockets, we need to clear the bpf_skb_cb() area
 535          * to not leak previous contents to user space.
 536          */
 537         BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) != BPF_SKB_CB_LEN);
 538         BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) !=
 539                      FIELD_SIZEOF(struct qdisc_skb_cb, data));
 540
 541         return qdisc_skb_cb(skb)->data;
 542 }
 543
 544 static inline u32 bpf_prog_run_save_cb(const struct bpf_prog *prog,
 545                                        struct sk_buff *skb)
 546 {
 547         u8 *cb_data = bpf_skb_cb(skb);
 548         u8 cb_saved[BPF_SKB_CB_LEN];
 549         u32 res;
 550
 551         if (unlikely(prog->cb_access)) {
 552                 memcpy(cb_saved, cb_data, sizeof(cb_saved));
 553                 memset(cb_data, 0, sizeof(cb_saved));
 554         }
 555
 556         res = BPF_PROG_RUN(prog, skb);
 557
 558         if (unlikely(prog->cb_access))
 559                 memcpy(cb_data, cb_saved, sizeof(cb_saved));
 560
 561         return res;
 562 }
 563
 564 static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog,
 565                                         struct sk_buff *skb)
 566 {
 567         u8 *cb_data = bpf_skb_cb(skb);
 568
 569         if (unlikely(prog->cb_access))
 570                 memset(cb_data, 0, BPF_SKB_CB_LEN);
 571
 572         return BPF_PROG_RUN(prog, skb);
 573 }
 574
 575 static __always_inline u32 bpf_prog_run_xdp(const struct bpf_prog *prog,
 576                                             struct xdp_buff *xdp)
 577 {
 578         /* Caller needs to hold rcu_read_lock() (!), otherwise program
 579          * can be released while still running, or map elements could be
 580          * freed early while still having concurrent users. XDP fastpath
 581          * already takes rcu_read_lock() when fetching the program, so
 582          * it's not necessary here anymore.
 583          */
 584         return BPF_PROG_RUN(prog, xdp);
 585 }
 586
 587 static inline u32 bpf_prog_insn_size(const struct bpf_prog *prog)
 588 {
 589         return prog->len * sizeof(struct bpf_insn);
 590 }
 591
 592 static inline u32 bpf_prog_tag_scratch_size(const struct bpf_prog *prog)
 593 {
 594         return round_up(bpf_prog_insn_size(prog) +
 595                         sizeof(__be64) + 1, SHA_MESSAGE_BYTES);
 596 }
 597
 598 static inline unsigned int bpf_prog_size(unsigned int proglen)
 599 {
 600         return max(sizeof(struct bpf_prog),
 601                    offsetof(struct bpf_prog, insns[proglen]));
 602 }
 603
 604 static inline bool bpf_prog_was_classic(const struct bpf_prog *prog)
 605 {
 606         /* When classic BPF programs have been loaded and the arch
 607          * does not have a classic BPF JIT (anymore), they have been
 608          * converted via bpf_migrate_filter() to eBPF and thus always
 609          * have an unspec program type.
 610          */
 611         return prog->type == BPF_PROG_TYPE_UNSPEC;
 612 }
 613
 614 static inline bool
 615 bpf_ctx_narrow_access_ok(u32 off, u32 size, const u32 size_default)
 616 {
 617         bool off_ok;
 618 #ifdef __LITTLE_ENDIAN
 619         off_ok = (off & (size_default - 1)) == 0;
 620 #else
 621         off_ok = (off & (size_default - 1)) + size == size_default;
 622 #endif
 623         return off_ok && size <= size_default && (size & (size - 1)) == 0;
 624 }
 625
 626 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
 627
 628 #ifdef CONFIG_ARCH_HAS_SET_MEMORY
 629 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 630 {
 631         fp->locked = 1;
 632         WARN_ON_ONCE(set_memory_ro((unsigned long)fp, fp->pages));
 633 }
 634
 635 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 636 {
 637         if (fp->locked) {
 638                 WARN_ON_ONCE(set_memory_rw((unsigned long)fp, fp->pages));
 639                 /* In case set_memory_rw() fails, we want to be the first
 640                  * to crash here instead of some random place later on.
 641                  */
 642                 fp->locked = 0;
 643         }
 644 }
 645
 646 static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
 647 {
 648         WARN_ON_ONCE(set_memory_ro((unsigned long)hdr, hdr->pages));
 649 }
 650
 651 static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
 652 {
 653         WARN_ON_ONCE(set_memory_rw((unsigned long)hdr, hdr->pages));
 654 }
 655 #else
 656 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 657 {
 658 }
 659
 660 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 661 {
 662 }
 663
 664 static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
 665 {
 666 }
 667
 668 static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
 669 {
 670 }
 671 #endif /* CONFIG_ARCH_HAS_SET_MEMORY */
 672
 673 static inline struct bpf_binary_header *
 674 bpf_jit_binary_hdr(const struct bpf_prog *fp)
 675 {
 676         unsigned long real_start = (unsigned long)fp->bpf_func;
 677         unsigned long addr = real_start & PAGE_MASK;
 678
 679         return (void *)addr;
 680 }
 681
 682 int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap);
 683 static inline int sk_filter(struct sock *sk, struct sk_buff *skb)
 684 {
 685         return sk_filter_trim_cap(sk, skb, 1);
 686 }
 687
 688 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err);
 689 void bpf_prog_free(struct bpf_prog *fp);
 690
 691 bool bpf_opcode_in_insntable(u8 code);
 692
 693 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
 694 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 695                                   gfp_t gfp_extra_flags);
 696 void __bpf_prog_free(struct bpf_prog *fp);
 697
 698 static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
 699 {
 700         bpf_prog_unlock_ro(fp);
 701         __bpf_prog_free(fp);
 702 }
 703
 704 typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter,
 705                                        unsigned int flen);
 706
 707 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
 708 int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
 709                               bpf_aux_classic_check_t trans, bool save_orig);
 710 void bpf_prog_destroy(struct bpf_prog *fp);
 711
 712 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 713 int sk_attach_bpf(u32 ufd, struct sock *sk);
 714 int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 715 int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk);
 716 int sk_detach_filter(struct sock *sk);
 717 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
 718                   unsigned int len);
 719
 720 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
 721 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
 722
 723 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 724 #define __bpf_call_base_args \
 725         ((u64 (*)(u64, u64, u64, u64, u64, const struct bpf_insn *)) \
 726          __bpf_call_base)
 727
 728 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog);
 729 void bpf_jit_compile(struct bpf_prog *prog);
 730 bool bpf_helper_changes_pkt_data(void *func);
 731
 732 static inline bool bpf_dump_raw_ok(void)
 733 {
 734         /* Reconstruction of call-sites is dependent on kallsyms,
 735          * thus make dump the same restriction.
 736          */
 737         return kallsyms_show_value() == 1;
 738 }
 739
 740 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
 741                                        const struct bpf_insn *patch, u32 len);
 742
 743 /* The pair of xdp_do_redirect and xdp_do_flush_map MUST be called in the
 744  * same cpu context. Further for best results no more than a single map
 745  * for the do_redirect/do_flush pair should be used. This limitation is
 746  * because we only track one map and force a flush when the map changes.
 747  * This does not appear to be a real limitation for existing software.
 748  */
 749 int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb,
 750                             struct bpf_prog *prog);
 751 int xdp_do_redirect(struct net_device *dev,
 752                     struct xdp_buff *xdp,
 753                     struct bpf_prog *prog);
 754 void xdp_do_flush_map(void);
 755
 756 /* Drivers not supporting XDP metadata can use this helper, which
 757  * rejects any room expansion for metadata as a result.
 758  */
 759 static __always_inline void
 760 xdp_set_data_meta_invalid(struct xdp_buff *xdp)
 761 {
 762         xdp->data_meta = xdp->data + 1;
 763 }
 764
 765 static __always_inline bool
 766 xdp_data_meta_unsupported(const struct xdp_buff *xdp)
 767 {
 768         return unlikely(xdp->data_meta > xdp->data);
 769 }
 770
 771 void bpf_warn_invalid_xdp_action(u32 act);
 772
 773 struct sock *do_sk_redirect_map(struct sk_buff *skb);
 774
 775 #ifdef CONFIG_BPF_JIT
 776 extern int bpf_jit_enable;
 777 extern int bpf_jit_harden;
 778 extern int bpf_jit_kallsyms;
 779
 780 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
 781
 782 struct bpf_binary_header *
 783 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 784                      unsigned int alignment,
 785                      bpf_jit_fill_hole_t bpf_fill_ill_insns);
 786 void bpf_jit_binary_free(struct bpf_binary_header *hdr);
 787
 788 void bpf_jit_free(struct bpf_prog *fp);
 789
 790 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *fp);
 791 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other);
 792
 793 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
 794                                 u32 pass, void *image)
 795 {
 796         pr_err("flen=%u proglen=%u pass=%u image=%pK from=%s pid=%d\n", flen,
 797                proglen, pass, image, current->comm, task_pid_nr(current));
 798
 799         if (image)
 800                 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
 801                                16, 1, image, proglen, false);
 802 }
 803
 804 static inline bool bpf_jit_is_ebpf(void)
 805 {
 806 # ifdef CONFIG_HAVE_EBPF_JIT
 807         return true;
 808 # else
 809         return false;
 810 # endif
 811 }
 812
 813 static inline bool ebpf_jit_enabled(void)
 814 {
 815         return bpf_jit_enable && bpf_jit_is_ebpf();
 816 }
 817
 818 static inline bool bpf_prog_ebpf_jited(const struct bpf_prog *fp)
 819 {
 820         return fp->jited && bpf_jit_is_ebpf();
 821 }
 822
 823 static inline bool bpf_jit_blinding_enabled(struct bpf_prog *prog)
 824 {
 825         /* These are the prerequisites, should someone ever have the
 826          * idea to call blinding outside of them, we make sure to
 827          * bail out.
 828          */
 829         if (!bpf_jit_is_ebpf())
 830                 return false;
 831         if (!prog->jit_requested)
 832                 return false;
 833         if (!bpf_jit_harden)
 834                 return false;
 835         if (bpf_jit_harden == 1 && capable(CAP_SYS_ADMIN))
 836                 return false;
 837
 838         return true;
 839 }
 840
 841 static inline bool bpf_jit_kallsyms_enabled(void)
 842 {
 843         /* There are a couple of corner cases where kallsyms should
 844          * not be enabled f.e. on hardening.
 845          */
 846         if (bpf_jit_harden)
 847                 return false;
 848         if (!bpf_jit_kallsyms)
 849                 return false;
 850         if (bpf_jit_kallsyms == 1)
 851                 return true;
 852
 853         return false;
 854 }
 855
 856 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
 857                                  unsigned long *off, char *sym);
 858 bool is_bpf_text_address(unsigned long addr);
 859 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 860                     char *sym);
 861
 862 static inline const char *
 863 bpf_address_lookup(unsigned long addr, unsigned long *size,
 864                    unsigned long *off, char **modname, char *sym)
 865 {
 866         const char *ret = __bpf_address_lookup(addr, size, off, sym);
 867
 868         if (ret && modname)
 869                 *modname = NULL;
 870         return ret;
 871 }
 872
 873 void bpf_prog_kallsyms_add(struct bpf_prog *fp);
 874 void bpf_prog_kallsyms_del(struct bpf_prog *fp);
 875
 876 #else /* CONFIG_BPF_JIT */
 877
 878 static inline bool ebpf_jit_enabled(void)
 879 {
 880         return false;
 881 }
 882
 883 static inline bool bpf_prog_ebpf_jited(const struct bpf_prog *fp)
 884 {
 885         return false;
 886 }
 887
 888 static inline void bpf_jit_free(struct bpf_prog *fp)
 889 {
 890         bpf_prog_unlock_free(fp);
 891 }
 892
 893 static inline bool bpf_jit_kallsyms_enabled(void)
 894 {
 895         return false;
 896 }
 897
 898 static inline const char *
 899 __bpf_address_lookup(unsigned long addr, unsigned long *size,
 900                      unsigned long *off, char *sym)
 901 {
 902         return NULL;
 903 }
 904
 905 static inline bool is_bpf_text_address(unsigned long addr)
 906 {
 907         return false;
 908 }
 909
 910 static inline int bpf_get_kallsym(unsigned int symnum, unsigned long *value,
 911                                   char *type, char *sym)
 912 {
 913         return -ERANGE;
 914 }
 915
 916 static inline const char *
 917 bpf_address_lookup(unsigned long addr, unsigned long *size,
 918                    unsigned long *off, char **modname, char *sym)
 919 {
 920         return NULL;
 921 }
 922
 923 static inline void bpf_prog_kallsyms_add(struct bpf_prog *fp)
 924 {
 925 }
 926
 927 static inline void bpf_prog_kallsyms_del(struct bpf_prog *fp)
 928 {
 929 }
 930 #endif /* CONFIG_BPF_JIT */
 931
 932 #define BPF_ANC         BIT(15)
 933
 934 static inline bool bpf_needs_clear_a(const struct sock_filter *first)
 935 {
 936         switch (first->code) {
 937         case BPF_RET | BPF_K:
 938         case BPF_LD | BPF_W | BPF_LEN:
 939                 return false;
 940
 941         case BPF_LD | BPF_W | BPF_ABS:
 942         case BPF_LD | BPF_H | BPF_ABS:
 943         case BPF_LD | BPF_B | BPF_ABS:
 944                 if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
 945                         return true;
 946                 return false;
 947
 948         default:
 949                 return true;
 950         }
 951 }
 952
 953 static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
 954 {
 955         BUG_ON(ftest->code & BPF_ANC);
 956
 957         switch (ftest->code) {
 958         case BPF_LD | BPF_W | BPF_ABS:
 959         case BPF_LD | BPF_H | BPF_ABS:
 960         case BPF_LD | BPF_B | BPF_ABS:
 961 #define BPF_ANCILLARY(CODE)     case SKF_AD_OFF + SKF_AD_##CODE:        \
 962                                 return BPF_ANC | SKF_AD_##CODE
 963                 switch (ftest->k) {
 964                 BPF_ANCILLARY(PROTOCOL);
 965                 BPF_ANCILLARY(PKTTYPE);
 966                 BPF_ANCILLARY(IFINDEX);
 967                 BPF_ANCILLARY(NLATTR);
 968                 BPF_ANCILLARY(NLATTR_NEST);
 969                 BPF_ANCILLARY(MARK);
 970                 BPF_ANCILLARY(QUEUE);
 971                 BPF_ANCILLARY(HATYPE);
 972                 BPF_ANCILLARY(RXHASH);
 973                 BPF_ANCILLARY(CPU);
 974                 BPF_ANCILLARY(ALU_XOR_X);
 975                 BPF_ANCILLARY(VLAN_TAG);
 976                 BPF_ANCILLARY(VLAN_TAG_PRESENT);
 977                 BPF_ANCILLARY(PAY_OFFSET);
 978                 BPF_ANCILLARY(RANDOM);
 979                 BPF_ANCILLARY(VLAN_TPID);
 980                 }
 981                 /* Fallthrough. */
 982         default:
 983                 return ftest->code;
 984         }
 985 }
 986
 987 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
 988                                            int k, unsigned int size);
 989
 990 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
 991                                      unsigned int size, void *buffer)
 992 {
 993         if (k >= 0)
 994                 return skb_header_pointer(skb, k, size, buffer);
 995
 996         return bpf_internal_load_pointer_neg_helper(skb, k, size);
 997 }
 998
 999 static inline int bpf_tell_extensions(void)
1000 {
1001         return SKF_AD_MAX;
1002 }
1003
1004 struct bpf_sock_ops_kern {
1005         struct  sock *sk;
1006         u32     op;
1007         union {
1008                 u32 args[4];
1009                 u32 reply;
1010                 u32 replylong[4];
1011         };
1012         u32     is_fullsock;
1013         u64     temp;                   /* temp and everything after is not
1014                                          * initialized to 0 before calling
1015                                          * the BPF program. New fields that
1016                                          * should be initialized to 0 should
1017                                          * be inserted before temp.
1018                                          * temp is scratch storage used by
1019                                          * sock_ops_convert_ctx_access
1020                                          * as temporary storage of a register.
1021                                          */
1022 };
1023
1024 #endif /* __LINUX_FILTER_H__ */