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