1 /* 2 * Linux Socket Filter - Kernel level socket filtering 3 * 4 * Based on the design of the Berkeley Packet Filter. The new 5 * internal format has been designed by PLUMgrid: 6 * 7 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com 8 * 9 * Authors: 10 * 11 * Jay Schulist <jschlst@samba.org> 12 * Alexei Starovoitov <ast@plumgrid.com> 13 * Daniel Borkmann <dborkman@redhat.com> 14 * 15 * This program is free software; you can redistribute it and/or 16 * modify it under the terms of the GNU General Public License 17 * as published by the Free Software Foundation; either version 18 * 2 of the License, or (at your option) any later version. 19 * 20 * Andi Kleen - Fix a few bad bugs and races. 21 * Kris Katterjohn - Added many additional checks in bpf_check_classic() 22 */ 23 24 #include <linux/filter.h> 25 #include <linux/skbuff.h> 26 #include <linux/vmalloc.h> 27 #include <linux/random.h> 28 #include <linux/moduleloader.h> 29 #include <linux/bpf.h> 30 31 #include <asm/unaligned.h> 32 33 /* Registers */ 34 #define BPF_R0 regs[BPF_REG_0] 35 #define BPF_R1 regs[BPF_REG_1] 36 #define BPF_R2 regs[BPF_REG_2] 37 #define BPF_R3 regs[BPF_REG_3] 38 #define BPF_R4 regs[BPF_REG_4] 39 #define BPF_R5 regs[BPF_REG_5] 40 #define BPF_R6 regs[BPF_REG_6] 41 #define BPF_R7 regs[BPF_REG_7] 42 #define BPF_R8 regs[BPF_REG_8] 43 #define BPF_R9 regs[BPF_REG_9] 44 #define BPF_R10 regs[BPF_REG_10] 45 46 /* Named registers */ 47 #define DST regs[insn->dst_reg] 48 #define SRC regs[insn->src_reg] 49 #define FP regs[BPF_REG_FP] 50 #define ARG1 regs[BPF_REG_ARG1] 51 #define CTX regs[BPF_REG_CTX] 52 #define IMM insn->imm 53 54 /* No hurry in this branch 55 * 56 * Exported for the bpf jit load helper. 57 */ 58 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 59 { 60 u8 *ptr = NULL; 61 62 if (k >= SKF_NET_OFF) 63 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 64 else if (k >= SKF_LL_OFF) 65 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 66 67 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 68 return ptr; 69 70 return NULL; 71 } 72 73 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 74 { 75 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO | 76 gfp_extra_flags; 77 struct bpf_prog_aux *aux; 78 struct bpf_prog *fp; 79 80 size = round_up(size, PAGE_SIZE); 81 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL); 82 if (fp == NULL) 83 return NULL; 84 85 kmemcheck_annotate_bitfield(fp, meta); 86 87 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags); 88 if (aux == NULL) { 89 vfree(fp); 90 return NULL; 91 } 92 93 fp->pages = size / PAGE_SIZE; 94 fp->aux = aux; 95 fp->aux->prog = fp; 96 97 return fp; 98 } 99 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 100 101 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 102 gfp_t gfp_extra_flags) 103 { 104 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO | 105 gfp_extra_flags; 106 struct bpf_prog *fp; 107 108 BUG_ON(fp_old == NULL); 109 110 size = round_up(size, PAGE_SIZE); 111 if (size <= fp_old->pages * PAGE_SIZE) 112 return fp_old; 113 114 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL); 115 if (fp != NULL) { 116 kmemcheck_annotate_bitfield(fp, meta); 117 118 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 119 fp->pages = size / PAGE_SIZE; 120 fp->aux->prog = fp; 121 122 /* We keep fp->aux from fp_old around in the new 123 * reallocated structure. 124 */ 125 fp_old->aux = NULL; 126 __bpf_prog_free(fp_old); 127 } 128 129 return fp; 130 } 131 EXPORT_SYMBOL_GPL(bpf_prog_realloc); 132 133 void __bpf_prog_free(struct bpf_prog *fp) 134 { 135 kfree(fp->aux); 136 vfree(fp); 137 } 138 EXPORT_SYMBOL_GPL(__bpf_prog_free); 139 140 #ifdef CONFIG_BPF_JIT 141 struct bpf_binary_header * 142 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 143 unsigned int alignment, 144 bpf_jit_fill_hole_t bpf_fill_ill_insns) 145 { 146 struct bpf_binary_header *hdr; 147 unsigned int size, hole, start; 148 149 /* Most of BPF filters are really small, but if some of them 150 * fill a page, allow at least 128 extra bytes to insert a 151 * random section of illegal instructions. 152 */ 153 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 154 hdr = module_alloc(size); 155 if (hdr == NULL) 156 return NULL; 157 158 /* Fill space with illegal/arch-dep instructions. */ 159 bpf_fill_ill_insns(hdr, size); 160 161 hdr->pages = size / PAGE_SIZE; 162 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 163 PAGE_SIZE - sizeof(*hdr)); 164 start = (prandom_u32() % hole) & ~(alignment - 1); 165 166 /* Leave a random number of instructions before BPF code. */ 167 *image_ptr = &hdr->image[start]; 168 169 return hdr; 170 } 171 172 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 173 { 174 module_memfree(hdr); 175 } 176 #endif /* CONFIG_BPF_JIT */ 177 178 /* Base function for offset calculation. Needs to go into .text section, 179 * therefore keeping it non-static as well; will also be used by JITs 180 * anyway later on, so do not let the compiler omit it. 181 */ 182 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 183 { 184 return 0; 185 } 186 EXPORT_SYMBOL_GPL(__bpf_call_base); 187 188 /** 189 * __bpf_prog_run - run eBPF program on a given context 190 * @ctx: is the data we are operating on 191 * @insn: is the array of eBPF instructions 192 * 193 * Decode and execute eBPF instructions. 194 */ 195 static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn) 196 { 197 u64 stack[MAX_BPF_STACK / sizeof(u64)]; 198 u64 regs[MAX_BPF_REG], tmp; 199 static const void *jumptable[256] = { 200 [0 ... 255] = &&default_label, 201 /* Now overwrite non-defaults ... */ 202 /* 32 bit ALU operations */ 203 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X, 204 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K, 205 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X, 206 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K, 207 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X, 208 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K, 209 [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X, 210 [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K, 211 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X, 212 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K, 213 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X, 214 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K, 215 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X, 216 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K, 217 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X, 218 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K, 219 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X, 220 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K, 221 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X, 222 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K, 223 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X, 224 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K, 225 [BPF_ALU | BPF_NEG] = &&ALU_NEG, 226 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE, 227 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE, 228 /* 64 bit ALU operations */ 229 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X, 230 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K, 231 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X, 232 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K, 233 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X, 234 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K, 235 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X, 236 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K, 237 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X, 238 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K, 239 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X, 240 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K, 241 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X, 242 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K, 243 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X, 244 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K, 245 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X, 246 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K, 247 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X, 248 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K, 249 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X, 250 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K, 251 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X, 252 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K, 253 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG, 254 /* Call instruction */ 255 [BPF_JMP | BPF_CALL] = &&JMP_CALL, 256 [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL, 257 /* Jumps */ 258 [BPF_JMP | BPF_JA] = &&JMP_JA, 259 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X, 260 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K, 261 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X, 262 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K, 263 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X, 264 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K, 265 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X, 266 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K, 267 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X, 268 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K, 269 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X, 270 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K, 271 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X, 272 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K, 273 /* Program return */ 274 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT, 275 /* Store instructions */ 276 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B, 277 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H, 278 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W, 279 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW, 280 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W, 281 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW, 282 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B, 283 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H, 284 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W, 285 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW, 286 /* Load instructions */ 287 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B, 288 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H, 289 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W, 290 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW, 291 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W, 292 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H, 293 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B, 294 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W, 295 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H, 296 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B, 297 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW, 298 }; 299 u32 tail_call_cnt = 0; 300 void *ptr; 301 int off; 302 303 #define CONT ({ insn++; goto select_insn; }) 304 #define CONT_JMP ({ insn++; goto select_insn; }) 305 306 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; 307 ARG1 = (u64) (unsigned long) ctx; 308 309 /* Registers used in classic BPF programs need to be reset first. */ 310 regs[BPF_REG_A] = 0; 311 regs[BPF_REG_X] = 0; 312 313 select_insn: 314 goto *jumptable[insn->code]; 315 316 /* ALU */ 317 #define ALU(OPCODE, OP) \ 318 ALU64_##OPCODE##_X: \ 319 DST = DST OP SRC; \ 320 CONT; \ 321 ALU_##OPCODE##_X: \ 322 DST = (u32) DST OP (u32) SRC; \ 323 CONT; \ 324 ALU64_##OPCODE##_K: \ 325 DST = DST OP IMM; \ 326 CONT; \ 327 ALU_##OPCODE##_K: \ 328 DST = (u32) DST OP (u32) IMM; \ 329 CONT; 330 331 ALU(ADD, +) 332 ALU(SUB, -) 333 ALU(AND, &) 334 ALU(OR, |) 335 ALU(LSH, <<) 336 ALU(RSH, >>) 337 ALU(XOR, ^) 338 ALU(MUL, *) 339 #undef ALU 340 ALU_NEG: 341 DST = (u32) -DST; 342 CONT; 343 ALU64_NEG: 344 DST = -DST; 345 CONT; 346 ALU_MOV_X: 347 DST = (u32) SRC; 348 CONT; 349 ALU_MOV_K: 350 DST = (u32) IMM; 351 CONT; 352 ALU64_MOV_X: 353 DST = SRC; 354 CONT; 355 ALU64_MOV_K: 356 DST = IMM; 357 CONT; 358 LD_IMM_DW: 359 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 360 insn++; 361 CONT; 362 ALU64_ARSH_X: 363 (*(s64 *) &DST) >>= SRC; 364 CONT; 365 ALU64_ARSH_K: 366 (*(s64 *) &DST) >>= IMM; 367 CONT; 368 ALU64_MOD_X: 369 if (unlikely(SRC == 0)) 370 return 0; 371 div64_u64_rem(DST, SRC, &tmp); 372 DST = tmp; 373 CONT; 374 ALU_MOD_X: 375 if (unlikely(SRC == 0)) 376 return 0; 377 tmp = (u32) DST; 378 DST = do_div(tmp, (u32) SRC); 379 CONT; 380 ALU64_MOD_K: 381 div64_u64_rem(DST, IMM, &tmp); 382 DST = tmp; 383 CONT; 384 ALU_MOD_K: 385 tmp = (u32) DST; 386 DST = do_div(tmp, (u32) IMM); 387 CONT; 388 ALU64_DIV_X: 389 if (unlikely(SRC == 0)) 390 return 0; 391 DST = div64_u64(DST, SRC); 392 CONT; 393 ALU_DIV_X: 394 if (unlikely(SRC == 0)) 395 return 0; 396 tmp = (u32) DST; 397 do_div(tmp, (u32) SRC); 398 DST = (u32) tmp; 399 CONT; 400 ALU64_DIV_K: 401 DST = div64_u64(DST, IMM); 402 CONT; 403 ALU_DIV_K: 404 tmp = (u32) DST; 405 do_div(tmp, (u32) IMM); 406 DST = (u32) tmp; 407 CONT; 408 ALU_END_TO_BE: 409 switch (IMM) { 410 case 16: 411 DST = (__force u16) cpu_to_be16(DST); 412 break; 413 case 32: 414 DST = (__force u32) cpu_to_be32(DST); 415 break; 416 case 64: 417 DST = (__force u64) cpu_to_be64(DST); 418 break; 419 } 420 CONT; 421 ALU_END_TO_LE: 422 switch (IMM) { 423 case 16: 424 DST = (__force u16) cpu_to_le16(DST); 425 break; 426 case 32: 427 DST = (__force u32) cpu_to_le32(DST); 428 break; 429 case 64: 430 DST = (__force u64) cpu_to_le64(DST); 431 break; 432 } 433 CONT; 434 435 /* CALL */ 436 JMP_CALL: 437 /* Function call scratches BPF_R1-BPF_R5 registers, 438 * preserves BPF_R6-BPF_R9, and stores return value 439 * into BPF_R0. 440 */ 441 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 442 BPF_R4, BPF_R5); 443 CONT; 444 445 JMP_TAIL_CALL: { 446 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 447 struct bpf_array *array = container_of(map, struct bpf_array, map); 448 struct bpf_prog *prog; 449 u64 index = BPF_R3; 450 451 if (unlikely(index >= array->map.max_entries)) 452 goto out; 453 454 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) 455 goto out; 456 457 tail_call_cnt++; 458 459 prog = READ_ONCE(array->ptrs[index]); 460 if (unlikely(!prog)) 461 goto out; 462 463 /* ARG1 at this point is guaranteed to point to CTX from 464 * the verifier side due to the fact that the tail call is 465 * handeled like a helper, that is, bpf_tail_call_proto, 466 * where arg1_type is ARG_PTR_TO_CTX. 467 */ 468 insn = prog->insnsi; 469 goto select_insn; 470 out: 471 CONT; 472 } 473 /* JMP */ 474 JMP_JA: 475 insn += insn->off; 476 CONT; 477 JMP_JEQ_X: 478 if (DST == SRC) { 479 insn += insn->off; 480 CONT_JMP; 481 } 482 CONT; 483 JMP_JEQ_K: 484 if (DST == IMM) { 485 insn += insn->off; 486 CONT_JMP; 487 } 488 CONT; 489 JMP_JNE_X: 490 if (DST != SRC) { 491 insn += insn->off; 492 CONT_JMP; 493 } 494 CONT; 495 JMP_JNE_K: 496 if (DST != IMM) { 497 insn += insn->off; 498 CONT_JMP; 499 } 500 CONT; 501 JMP_JGT_X: 502 if (DST > SRC) { 503 insn += insn->off; 504 CONT_JMP; 505 } 506 CONT; 507 JMP_JGT_K: 508 if (DST > IMM) { 509 insn += insn->off; 510 CONT_JMP; 511 } 512 CONT; 513 JMP_JGE_X: 514 if (DST >= SRC) { 515 insn += insn->off; 516 CONT_JMP; 517 } 518 CONT; 519 JMP_JGE_K: 520 if (DST >= IMM) { 521 insn += insn->off; 522 CONT_JMP; 523 } 524 CONT; 525 JMP_JSGT_X: 526 if (((s64) DST) > ((s64) SRC)) { 527 insn += insn->off; 528 CONT_JMP; 529 } 530 CONT; 531 JMP_JSGT_K: 532 if (((s64) DST) > ((s64) IMM)) { 533 insn += insn->off; 534 CONT_JMP; 535 } 536 CONT; 537 JMP_JSGE_X: 538 if (((s64) DST) >= ((s64) SRC)) { 539 insn += insn->off; 540 CONT_JMP; 541 } 542 CONT; 543 JMP_JSGE_K: 544 if (((s64) DST) >= ((s64) IMM)) { 545 insn += insn->off; 546 CONT_JMP; 547 } 548 CONT; 549 JMP_JSET_X: 550 if (DST & SRC) { 551 insn += insn->off; 552 CONT_JMP; 553 } 554 CONT; 555 JMP_JSET_K: 556 if (DST & IMM) { 557 insn += insn->off; 558 CONT_JMP; 559 } 560 CONT; 561 JMP_EXIT: 562 return BPF_R0; 563 564 /* STX and ST and LDX*/ 565 #define LDST(SIZEOP, SIZE) \ 566 STX_MEM_##SIZEOP: \ 567 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 568 CONT; \ 569 ST_MEM_##SIZEOP: \ 570 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 571 CONT; \ 572 LDX_MEM_##SIZEOP: \ 573 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 574 CONT; 575 576 LDST(B, u8) 577 LDST(H, u16) 578 LDST(W, u32) 579 LDST(DW, u64) 580 #undef LDST 581 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */ 582 atomic_add((u32) SRC, (atomic_t *)(unsigned long) 583 (DST + insn->off)); 584 CONT; 585 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */ 586 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long) 587 (DST + insn->off)); 588 CONT; 589 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */ 590 off = IMM; 591 load_word: 592 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are 593 * only appearing in the programs where ctx == 594 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX] 595 * == BPF_R6, bpf_convert_filter() saves it in BPF_R6, 596 * internal BPF verifier will check that BPF_R6 == 597 * ctx. 598 * 599 * BPF_ABS and BPF_IND are wrappers of function calls, 600 * so they scratch BPF_R1-BPF_R5 registers, preserve 601 * BPF_R6-BPF_R9, and store return value into BPF_R0. 602 * 603 * Implicit input: 604 * ctx == skb == BPF_R6 == CTX 605 * 606 * Explicit input: 607 * SRC == any register 608 * IMM == 32-bit immediate 609 * 610 * Output: 611 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness 612 */ 613 614 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp); 615 if (likely(ptr != NULL)) { 616 BPF_R0 = get_unaligned_be32(ptr); 617 CONT; 618 } 619 620 return 0; 621 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */ 622 off = IMM; 623 load_half: 624 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp); 625 if (likely(ptr != NULL)) { 626 BPF_R0 = get_unaligned_be16(ptr); 627 CONT; 628 } 629 630 return 0; 631 LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */ 632 off = IMM; 633 load_byte: 634 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp); 635 if (likely(ptr != NULL)) { 636 BPF_R0 = *(u8 *)ptr; 637 CONT; 638 } 639 640 return 0; 641 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */ 642 off = IMM + SRC; 643 goto load_word; 644 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */ 645 off = IMM + SRC; 646 goto load_half; 647 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */ 648 off = IMM + SRC; 649 goto load_byte; 650 651 default_label: 652 /* If we ever reach this, we have a bug somewhere. */ 653 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code); 654 return 0; 655 } 656 657 bool bpf_prog_array_compatible(struct bpf_array *array, 658 const struct bpf_prog *fp) 659 { 660 if (!array->owner_prog_type) { 661 /* There's no owner yet where we could check for 662 * compatibility. 663 */ 664 array->owner_prog_type = fp->type; 665 array->owner_jited = fp->jited; 666 667 return true; 668 } 669 670 return array->owner_prog_type == fp->type && 671 array->owner_jited == fp->jited; 672 } 673 674 static int bpf_check_tail_call(const struct bpf_prog *fp) 675 { 676 struct bpf_prog_aux *aux = fp->aux; 677 int i; 678 679 for (i = 0; i < aux->used_map_cnt; i++) { 680 struct bpf_map *map = aux->used_maps[i]; 681 struct bpf_array *array; 682 683 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) 684 continue; 685 686 array = container_of(map, struct bpf_array, map); 687 if (!bpf_prog_array_compatible(array, fp)) 688 return -EINVAL; 689 } 690 691 return 0; 692 } 693 694 /** 695 * bpf_prog_select_runtime - select exec runtime for BPF program 696 * @fp: bpf_prog populated with internal BPF program 697 * 698 * Try to JIT eBPF program, if JIT is not available, use interpreter. 699 * The BPF program will be executed via BPF_PROG_RUN() macro. 700 */ 701 int bpf_prog_select_runtime(struct bpf_prog *fp) 702 { 703 fp->bpf_func = (void *) __bpf_prog_run; 704 705 bpf_int_jit_compile(fp); 706 bpf_prog_lock_ro(fp); 707 708 /* The tail call compatibility check can only be done at 709 * this late stage as we need to determine, if we deal 710 * with JITed or non JITed program concatenations and not 711 * all eBPF JITs might immediately support all features. 712 */ 713 return bpf_check_tail_call(fp); 714 } 715 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 716 717 static void bpf_prog_free_deferred(struct work_struct *work) 718 { 719 struct bpf_prog_aux *aux; 720 721 aux = container_of(work, struct bpf_prog_aux, work); 722 bpf_jit_free(aux->prog); 723 } 724 725 /* Free internal BPF program */ 726 void bpf_prog_free(struct bpf_prog *fp) 727 { 728 struct bpf_prog_aux *aux = fp->aux; 729 730 INIT_WORK(&aux->work, bpf_prog_free_deferred); 731 schedule_work(&aux->work); 732 } 733 EXPORT_SYMBOL_GPL(bpf_prog_free); 734 735 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 736 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 737 738 void bpf_user_rnd_init_once(void) 739 { 740 prandom_init_once(&bpf_user_rnd_state); 741 } 742 743 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 744 { 745 /* Should someone ever have the rather unwise idea to use some 746 * of the registers passed into this function, then note that 747 * this function is called from native eBPF and classic-to-eBPF 748 * transformations. Register assignments from both sides are 749 * different, f.e. classic always sets fn(ctx, A, X) here. 750 */ 751 struct rnd_state *state; 752 u32 res; 753 754 state = &get_cpu_var(bpf_user_rnd_state); 755 res = prandom_u32_state(state); 756 put_cpu_var(state); 757 758 return res; 759 } 760 761 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 762 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 763 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 764 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 765 766 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 767 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 768 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 769 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 770 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 771 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 772 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 773 { 774 return NULL; 775 } 776 777 /* Always built-in helper functions. */ 778 const struct bpf_func_proto bpf_tail_call_proto = { 779 .func = NULL, 780 .gpl_only = false, 781 .ret_type = RET_VOID, 782 .arg1_type = ARG_PTR_TO_CTX, 783 .arg2_type = ARG_CONST_MAP_PTR, 784 .arg3_type = ARG_ANYTHING, 785 }; 786 787 /* For classic BPF JITs that don't implement bpf_int_jit_compile(). */ 788 void __weak bpf_int_jit_compile(struct bpf_prog *prog) 789 { 790 } 791 792 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 793 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 794 */ 795 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 796 int len) 797 { 798 return -EFAULT; 799 } 800