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 16 #include <asm/cacheflush.h> 17 18 #include <uapi/linux/filter.h> 19 #include <uapi/linux/bpf.h> 20 21 struct sk_buff; 22 struct sock; 23 struct seccomp_data; 24 struct bpf_prog_aux; 25 26 /* ArgX, context and stack frame pointer register positions. Note, 27 * Arg1, Arg2, Arg3, etc are used as argument mappings of function 28 * calls in BPF_CALL instruction. 29 */ 30 #define BPF_REG_ARG1 BPF_REG_1 31 #define BPF_REG_ARG2 BPF_REG_2 32 #define BPF_REG_ARG3 BPF_REG_3 33 #define BPF_REG_ARG4 BPF_REG_4 34 #define BPF_REG_ARG5 BPF_REG_5 35 #define BPF_REG_CTX BPF_REG_6 36 #define BPF_REG_FP BPF_REG_10 37 38 /* Additional register mappings for converted user programs. */ 39 #define BPF_REG_A BPF_REG_0 40 #define BPF_REG_X BPF_REG_7 41 #define BPF_REG_TMP BPF_REG_8 42 43 /* BPF program can access up to 512 bytes of stack space. */ 44 #define MAX_BPF_STACK 512 45 46 /* Helper macros for filter block array initializers. */ 47 48 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */ 49 50 #define BPF_ALU64_REG(OP, DST, SRC) \ 51 ((struct bpf_insn) { \ 52 .code = BPF_ALU64 | BPF_OP(OP) | BPF_X, \ 53 .dst_reg = DST, \ 54 .src_reg = SRC, \ 55 .off = 0, \ 56 .imm = 0 }) 57 58 #define BPF_ALU32_REG(OP, DST, SRC) \ 59 ((struct bpf_insn) { \ 60 .code = BPF_ALU | BPF_OP(OP) | BPF_X, \ 61 .dst_reg = DST, \ 62 .src_reg = SRC, \ 63 .off = 0, \ 64 .imm = 0 }) 65 66 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */ 67 68 #define BPF_ALU64_IMM(OP, DST, IMM) \ 69 ((struct bpf_insn) { \ 70 .code = BPF_ALU64 | BPF_OP(OP) | BPF_K, \ 71 .dst_reg = DST, \ 72 .src_reg = 0, \ 73 .off = 0, \ 74 .imm = IMM }) 75 76 #define BPF_ALU32_IMM(OP, DST, IMM) \ 77 ((struct bpf_insn) { \ 78 .code = BPF_ALU | BPF_OP(OP) | BPF_K, \ 79 .dst_reg = DST, \ 80 .src_reg = 0, \ 81 .off = 0, \ 82 .imm = IMM }) 83 84 /* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */ 85 86 #define BPF_ENDIAN(TYPE, DST, LEN) \ 87 ((struct bpf_insn) { \ 88 .code = BPF_ALU | BPF_END | BPF_SRC(TYPE), \ 89 .dst_reg = DST, \ 90 .src_reg = 0, \ 91 .off = 0, \ 92 .imm = LEN }) 93 94 /* Short form of mov, dst_reg = src_reg */ 95 96 #define BPF_MOV64_REG(DST, SRC) \ 97 ((struct bpf_insn) { \ 98 .code = BPF_ALU64 | BPF_MOV | BPF_X, \ 99 .dst_reg = DST, \ 100 .src_reg = SRC, \ 101 .off = 0, \ 102 .imm = 0 }) 103 104 #define BPF_MOV32_REG(DST, SRC) \ 105 ((struct bpf_insn) { \ 106 .code = BPF_ALU | BPF_MOV | BPF_X, \ 107 .dst_reg = DST, \ 108 .src_reg = SRC, \ 109 .off = 0, \ 110 .imm = 0 }) 111 112 /* Short form of mov, dst_reg = imm32 */ 113 114 #define BPF_MOV64_IMM(DST, IMM) \ 115 ((struct bpf_insn) { \ 116 .code = BPF_ALU64 | BPF_MOV | BPF_K, \ 117 .dst_reg = DST, \ 118 .src_reg = 0, \ 119 .off = 0, \ 120 .imm = IMM }) 121 122 #define BPF_MOV32_IMM(DST, IMM) \ 123 ((struct bpf_insn) { \ 124 .code = BPF_ALU | BPF_MOV | BPF_K, \ 125 .dst_reg = DST, \ 126 .src_reg = 0, \ 127 .off = 0, \ 128 .imm = IMM }) 129 130 /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */ 131 #define BPF_LD_IMM64(DST, IMM) \ 132 BPF_LD_IMM64_RAW(DST, 0, IMM) 133 134 #define BPF_LD_IMM64_RAW(DST, SRC, IMM) \ 135 ((struct bpf_insn) { \ 136 .code = BPF_LD | BPF_DW | BPF_IMM, \ 137 .dst_reg = DST, \ 138 .src_reg = SRC, \ 139 .off = 0, \ 140 .imm = (__u32) (IMM) }), \ 141 ((struct bpf_insn) { \ 142 .code = 0, /* zero is reserved opcode */ \ 143 .dst_reg = 0, \ 144 .src_reg = 0, \ 145 .off = 0, \ 146 .imm = ((__u64) (IMM)) >> 32 }) 147 148 /* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */ 149 #define BPF_LD_MAP_FD(DST, MAP_FD) \ 150 BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD) 151 152 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */ 153 154 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM) \ 155 ((struct bpf_insn) { \ 156 .code = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE), \ 157 .dst_reg = DST, \ 158 .src_reg = SRC, \ 159 .off = 0, \ 160 .imm = IMM }) 161 162 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM) \ 163 ((struct bpf_insn) { \ 164 .code = BPF_ALU | BPF_MOV | BPF_SRC(TYPE), \ 165 .dst_reg = DST, \ 166 .src_reg = SRC, \ 167 .off = 0, \ 168 .imm = IMM }) 169 170 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */ 171 172 #define BPF_LD_ABS(SIZE, IMM) \ 173 ((struct bpf_insn) { \ 174 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS, \ 175 .dst_reg = 0, \ 176 .src_reg = 0, \ 177 .off = 0, \ 178 .imm = IMM }) 179 180 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */ 181 182 #define BPF_LD_IND(SIZE, SRC, IMM) \ 183 ((struct bpf_insn) { \ 184 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_IND, \ 185 .dst_reg = 0, \ 186 .src_reg = SRC, \ 187 .off = 0, \ 188 .imm = IMM }) 189 190 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */ 191 192 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF) \ 193 ((struct bpf_insn) { \ 194 .code = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM, \ 195 .dst_reg = DST, \ 196 .src_reg = SRC, \ 197 .off = OFF, \ 198 .imm = 0 }) 199 200 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */ 201 202 #define BPF_STX_MEM(SIZE, DST, SRC, OFF) \ 203 ((struct bpf_insn) { \ 204 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM, \ 205 .dst_reg = DST, \ 206 .src_reg = SRC, \ 207 .off = OFF, \ 208 .imm = 0 }) 209 210 /* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */ 211 212 #define BPF_STX_XADD(SIZE, DST, SRC, OFF) \ 213 ((struct bpf_insn) { \ 214 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD, \ 215 .dst_reg = DST, \ 216 .src_reg = SRC, \ 217 .off = OFF, \ 218 .imm = 0 }) 219 220 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */ 221 222 #define BPF_ST_MEM(SIZE, DST, OFF, IMM) \ 223 ((struct bpf_insn) { \ 224 .code = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM, \ 225 .dst_reg = DST, \ 226 .src_reg = 0, \ 227 .off = OFF, \ 228 .imm = IMM }) 229 230 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */ 231 232 #define BPF_JMP_REG(OP, DST, SRC, OFF) \ 233 ((struct bpf_insn) { \ 234 .code = BPF_JMP | BPF_OP(OP) | BPF_X, \ 235 .dst_reg = DST, \ 236 .src_reg = SRC, \ 237 .off = OFF, \ 238 .imm = 0 }) 239 240 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */ 241 242 #define BPF_JMP_IMM(OP, DST, IMM, OFF) \ 243 ((struct bpf_insn) { \ 244 .code = BPF_JMP | BPF_OP(OP) | BPF_K, \ 245 .dst_reg = DST, \ 246 .src_reg = 0, \ 247 .off = OFF, \ 248 .imm = IMM }) 249 250 /* Function call */ 251 252 #define BPF_EMIT_CALL(FUNC) \ 253 ((struct bpf_insn) { \ 254 .code = BPF_JMP | BPF_CALL, \ 255 .dst_reg = 0, \ 256 .src_reg = 0, \ 257 .off = 0, \ 258 .imm = ((FUNC) - __bpf_call_base) }) 259 260 /* Raw code statement block */ 261 262 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM) \ 263 ((struct bpf_insn) { \ 264 .code = CODE, \ 265 .dst_reg = DST, \ 266 .src_reg = SRC, \ 267 .off = OFF, \ 268 .imm = IMM }) 269 270 /* Program exit */ 271 272 #define BPF_EXIT_INSN() \ 273 ((struct bpf_insn) { \ 274 .code = BPF_JMP | BPF_EXIT, \ 275 .dst_reg = 0, \ 276 .src_reg = 0, \ 277 .off = 0, \ 278 .imm = 0 }) 279 280 /* Internal classic blocks for direct assignment */ 281 282 #define __BPF_STMT(CODE, K) \ 283 ((struct sock_filter) BPF_STMT(CODE, K)) 284 285 #define __BPF_JUMP(CODE, K, JT, JF) \ 286 ((struct sock_filter) BPF_JUMP(CODE, K, JT, JF)) 287 288 #define bytes_to_bpf_size(bytes) \ 289 ({ \ 290 int bpf_size = -EINVAL; \ 291 \ 292 if (bytes == sizeof(u8)) \ 293 bpf_size = BPF_B; \ 294 else if (bytes == sizeof(u16)) \ 295 bpf_size = BPF_H; \ 296 else if (bytes == sizeof(u32)) \ 297 bpf_size = BPF_W; \ 298 else if (bytes == sizeof(u64)) \ 299 bpf_size = BPF_DW; \ 300 \ 301 bpf_size; \ 302 }) 303 304 /* Macro to invoke filter function. */ 305 #define SK_RUN_FILTER(filter, ctx) \ 306 (*filter->prog->bpf_func)(ctx, filter->prog->insnsi) 307 308 #ifdef CONFIG_COMPAT 309 /* A struct sock_filter is architecture independent. */ 310 struct compat_sock_fprog { 311 u16 len; 312 compat_uptr_t filter; /* struct sock_filter * */ 313 }; 314 #endif 315 316 struct sock_fprog_kern { 317 u16 len; 318 struct sock_filter *filter; 319 }; 320 321 struct bpf_binary_header { 322 unsigned int pages; 323 u8 image[]; 324 }; 325 326 struct bpf_prog { 327 u16 pages; /* Number of allocated pages */ 328 bool jited; /* Is our filter JIT'ed? */ 329 bool gpl_compatible; /* Is our filter GPL compatible? */ 330 u32 len; /* Number of filter blocks */ 331 enum bpf_prog_type type; /* Type of BPF program */ 332 struct bpf_prog_aux *aux; /* Auxiliary fields */ 333 struct sock_fprog_kern *orig_prog; /* Original BPF program */ 334 unsigned int (*bpf_func)(const struct sk_buff *skb, 335 const struct bpf_insn *filter); 336 /* Instructions for interpreter */ 337 union { 338 struct sock_filter insns[0]; 339 struct bpf_insn insnsi[0]; 340 }; 341 }; 342 343 struct sk_filter { 344 atomic_t refcnt; 345 struct rcu_head rcu; 346 struct bpf_prog *prog; 347 }; 348 349 #define BPF_PROG_RUN(filter, ctx) (*filter->bpf_func)(ctx, filter->insnsi) 350 351 static inline unsigned int bpf_prog_size(unsigned int proglen) 352 { 353 return max(sizeof(struct bpf_prog), 354 offsetof(struct bpf_prog, insns[proglen])); 355 } 356 357 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) 358 359 #ifdef CONFIG_DEBUG_SET_MODULE_RONX 360 static inline void bpf_prog_lock_ro(struct bpf_prog *fp) 361 { 362 set_memory_ro((unsigned long)fp, fp->pages); 363 } 364 365 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) 366 { 367 set_memory_rw((unsigned long)fp, fp->pages); 368 } 369 #else 370 static inline void bpf_prog_lock_ro(struct bpf_prog *fp) 371 { 372 } 373 374 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) 375 { 376 } 377 #endif /* CONFIG_DEBUG_SET_MODULE_RONX */ 378 379 int sk_filter(struct sock *sk, struct sk_buff *skb); 380 381 int bpf_prog_select_runtime(struct bpf_prog *fp); 382 void bpf_prog_free(struct bpf_prog *fp); 383 384 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags); 385 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 386 gfp_t gfp_extra_flags); 387 void __bpf_prog_free(struct bpf_prog *fp); 388 389 static inline void bpf_prog_unlock_free(struct bpf_prog *fp) 390 { 391 bpf_prog_unlock_ro(fp); 392 __bpf_prog_free(fp); 393 } 394 395 typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter, 396 unsigned int flen); 397 398 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog); 399 int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog, 400 bpf_aux_classic_check_t trans); 401 void bpf_prog_destroy(struct bpf_prog *fp); 402 403 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk); 404 int sk_attach_bpf(u32 ufd, struct sock *sk); 405 int sk_detach_filter(struct sock *sk); 406 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter, 407 unsigned int len); 408 409 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp); 410 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp); 411 412 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 413 void bpf_int_jit_compile(struct bpf_prog *fp); 414 415 #ifdef CONFIG_BPF_JIT 416 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size); 417 418 struct bpf_binary_header * 419 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 420 unsigned int alignment, 421 bpf_jit_fill_hole_t bpf_fill_ill_insns); 422 void bpf_jit_binary_free(struct bpf_binary_header *hdr); 423 424 void bpf_jit_compile(struct bpf_prog *fp); 425 void bpf_jit_free(struct bpf_prog *fp); 426 427 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen, 428 u32 pass, void *image) 429 { 430 pr_err("flen=%u proglen=%u pass=%u image=%pK\n", 431 flen, proglen, pass, image); 432 if (image) 433 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET, 434 16, 1, image, proglen, false); 435 } 436 #else 437 static inline void bpf_jit_compile(struct bpf_prog *fp) 438 { 439 } 440 441 static inline void bpf_jit_free(struct bpf_prog *fp) 442 { 443 bpf_prog_unlock_free(fp); 444 } 445 #endif /* CONFIG_BPF_JIT */ 446 447 #define BPF_ANC BIT(15) 448 449 static inline u16 bpf_anc_helper(const struct sock_filter *ftest) 450 { 451 BUG_ON(ftest->code & BPF_ANC); 452 453 switch (ftest->code) { 454 case BPF_LD | BPF_W | BPF_ABS: 455 case BPF_LD | BPF_H | BPF_ABS: 456 case BPF_LD | BPF_B | BPF_ABS: 457 #define BPF_ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \ 458 return BPF_ANC | SKF_AD_##CODE 459 switch (ftest->k) { 460 BPF_ANCILLARY(PROTOCOL); 461 BPF_ANCILLARY(PKTTYPE); 462 BPF_ANCILLARY(IFINDEX); 463 BPF_ANCILLARY(NLATTR); 464 BPF_ANCILLARY(NLATTR_NEST); 465 BPF_ANCILLARY(MARK); 466 BPF_ANCILLARY(QUEUE); 467 BPF_ANCILLARY(HATYPE); 468 BPF_ANCILLARY(RXHASH); 469 BPF_ANCILLARY(CPU); 470 BPF_ANCILLARY(ALU_XOR_X); 471 BPF_ANCILLARY(VLAN_TAG); 472 BPF_ANCILLARY(VLAN_TAG_PRESENT); 473 BPF_ANCILLARY(PAY_OFFSET); 474 BPF_ANCILLARY(RANDOM); 475 BPF_ANCILLARY(VLAN_TPID); 476 } 477 /* Fallthrough. */ 478 default: 479 return ftest->code; 480 } 481 } 482 483 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, 484 int k, unsigned int size); 485 486 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k, 487 unsigned int size, void *buffer) 488 { 489 if (k >= 0) 490 return skb_header_pointer(skb, k, size, buffer); 491 492 return bpf_internal_load_pointer_neg_helper(skb, k, size); 493 } 494 495 static inline int bpf_tell_extensions(void) 496 { 497 return SKF_AD_MAX; 498 } 499 500 #endif /* __LINUX_FILTER_H__ */ 501