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