1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com 3 * Copyright (c) 2016 Facebook 4 */ 5 6 #include <linux/bpf.h> 7 8 #include "disasm.h" 9 10 /* Only defined by the non-UAPI linux/filter.h, which this file cannot use. */ 11 #define BPF_PROBE_ATOMIC 0xe0 12 13 #define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x) 14 static const char * const func_id_str[] = { 15 __BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN) 16 }; 17 #undef __BPF_FUNC_STR_FN 18 19 static const char *__func_get_name(const struct bpf_insn_cbs *cbs, 20 const struct bpf_insn *insn, 21 char *buff, size_t len) 22 { 23 BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID); 24 25 if (!insn->src_reg && 26 insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID && 27 func_id_str[insn->imm]) 28 return func_id_str[insn->imm]; 29 30 if (cbs && cbs->cb_call) { 31 const char *res; 32 33 res = cbs->cb_call(cbs->private_data, insn); 34 if (res) 35 return res; 36 } 37 38 if (insn->src_reg == BPF_PSEUDO_CALL) 39 snprintf(buff, len, "%+d", insn->imm); 40 else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) 41 snprintf(buff, len, "kernel-function"); 42 43 return buff; 44 } 45 46 static const char *__func_imm_name(const struct bpf_insn_cbs *cbs, 47 const struct bpf_insn *insn, 48 u64 full_imm, char *buff, size_t len) 49 { 50 if (cbs && cbs->cb_imm) 51 return cbs->cb_imm(cbs->private_data, insn, full_imm); 52 53 snprintf(buff, len, "0x%llx", (unsigned long long)full_imm); 54 return buff; 55 } 56 57 const char *func_id_name(int id) 58 { 59 if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id]) 60 return func_id_str[id]; 61 else 62 return "unknown"; 63 } 64 65 const char *const bpf_class_string[8] = { 66 [BPF_LD] = "ld", 67 [BPF_LDX] = "ldx", 68 [BPF_ST] = "st", 69 [BPF_STX] = "stx", 70 [BPF_ALU] = "alu", 71 [BPF_JMP] = "jmp", 72 [BPF_JMP32] = "jmp32", 73 [BPF_ALU64] = "alu64", 74 }; 75 76 const char *const bpf_alu_string[16] = { 77 [BPF_ADD >> 4] = "+=", 78 [BPF_SUB >> 4] = "-=", 79 [BPF_MUL >> 4] = "*=", 80 [BPF_DIV >> 4] = "/=", 81 [BPF_OR >> 4] = "|=", 82 [BPF_AND >> 4] = "&=", 83 [BPF_LSH >> 4] = "<<=", 84 [BPF_RSH >> 4] = ">>=", 85 [BPF_NEG >> 4] = "neg", 86 [BPF_MOD >> 4] = "%=", 87 [BPF_XOR >> 4] = "^=", 88 [BPF_MOV >> 4] = "=", 89 [BPF_ARSH >> 4] = "s>>=", 90 [BPF_END >> 4] = "endian", 91 }; 92 93 static const char *const bpf_alu_sign_string[16] = { 94 [BPF_DIV >> 4] = "s/=", 95 [BPF_MOD >> 4] = "s%=", 96 }; 97 98 static const char *const bpf_movsx_string[4] = { 99 [0] = "(s8)", 100 [1] = "(s16)", 101 [3] = "(s32)", 102 }; 103 104 static const char *const bpf_atomic_alu_string[16] = { 105 [BPF_ADD >> 4] = "add", 106 [BPF_AND >> 4] = "and", 107 [BPF_OR >> 4] = "or", 108 [BPF_XOR >> 4] = "xor", 109 }; 110 111 static const char *const bpf_ldst_string[] = { 112 [BPF_W >> 3] = "u32", 113 [BPF_H >> 3] = "u16", 114 [BPF_B >> 3] = "u8", 115 [BPF_DW >> 3] = "u64", 116 }; 117 118 static const char *const bpf_ldsx_string[] = { 119 [BPF_W >> 3] = "s32", 120 [BPF_H >> 3] = "s16", 121 [BPF_B >> 3] = "s8", 122 }; 123 124 static const char *const bpf_jmp_string[16] = { 125 [BPF_JA >> 4] = "jmp", 126 [BPF_JEQ >> 4] = "==", 127 [BPF_JGT >> 4] = ">", 128 [BPF_JLT >> 4] = "<", 129 [BPF_JGE >> 4] = ">=", 130 [BPF_JLE >> 4] = "<=", 131 [BPF_JSET >> 4] = "&", 132 [BPF_JNE >> 4] = "!=", 133 [BPF_JSGT >> 4] = "s>", 134 [BPF_JSLT >> 4] = "s<", 135 [BPF_JSGE >> 4] = "s>=", 136 [BPF_JSLE >> 4] = "s<=", 137 [BPF_CALL >> 4] = "call", 138 [BPF_EXIT >> 4] = "exit", 139 }; 140 141 static void print_bpf_end_insn(bpf_insn_print_t verbose, 142 void *private_data, 143 const struct bpf_insn *insn) 144 { 145 verbose(private_data, "(%02x) r%d = %s%d r%d", 146 insn->code, insn->dst_reg, 147 BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le", 148 insn->imm, insn->dst_reg); 149 } 150 151 static void print_bpf_bswap_insn(bpf_insn_print_t verbose, 152 void *private_data, 153 const struct bpf_insn *insn) 154 { 155 verbose(private_data, "(%02x) r%d = bswap%d r%d", 156 insn->code, insn->dst_reg, 157 insn->imm, insn->dst_reg); 158 } 159 160 static bool is_sdiv_smod(const struct bpf_insn *insn) 161 { 162 return (BPF_OP(insn->code) == BPF_DIV || BPF_OP(insn->code) == BPF_MOD) && 163 insn->off == 1; 164 } 165 166 static bool is_movsx(const struct bpf_insn *insn) 167 { 168 return BPF_OP(insn->code) == BPF_MOV && 169 (insn->off == 8 || insn->off == 16 || insn->off == 32); 170 } 171 172 static bool is_addr_space_cast(const struct bpf_insn *insn) 173 { 174 return insn->code == (BPF_ALU64 | BPF_MOV | BPF_X) && 175 insn->off == BPF_ADDR_SPACE_CAST; 176 } 177 178 /* Special (internal-only) form of mov, used to resolve per-CPU addrs: 179 * dst_reg = src_reg + <percpu_base_off> 180 * BPF_ADDR_PERCPU is used as a special insn->off value. 181 */ 182 #define BPF_ADDR_PERCPU (-1) 183 184 static inline bool is_mov_percpu_addr(const struct bpf_insn *insn) 185 { 186 return insn->code == (BPF_ALU64 | BPF_MOV | BPF_X) && insn->off == BPF_ADDR_PERCPU; 187 } 188 189 void print_bpf_insn(const struct bpf_insn_cbs *cbs, 190 const struct bpf_insn *insn, 191 bool allow_ptr_leaks) 192 { 193 const bpf_insn_print_t verbose = cbs->cb_print; 194 u8 class = BPF_CLASS(insn->code); 195 196 if (class == BPF_ALU || class == BPF_ALU64) { 197 if (BPF_OP(insn->code) == BPF_END) { 198 if (class == BPF_ALU64) 199 print_bpf_bswap_insn(verbose, cbs->private_data, insn); 200 else 201 print_bpf_end_insn(verbose, cbs->private_data, insn); 202 } else if (BPF_OP(insn->code) == BPF_NEG) { 203 verbose(cbs->private_data, "(%02x) %c%d = -%c%d", 204 insn->code, class == BPF_ALU ? 'w' : 'r', 205 insn->dst_reg, class == BPF_ALU ? 'w' : 'r', 206 insn->dst_reg); 207 } else if (is_addr_space_cast(insn)) { 208 verbose(cbs->private_data, "(%02x) r%d = addr_space_cast(r%d, %u, %u)", 209 insn->code, insn->dst_reg, 210 insn->src_reg, ((u32)insn->imm) >> 16, (u16)insn->imm); 211 } else if (is_mov_percpu_addr(insn)) { 212 verbose(cbs->private_data, "(%02x) r%d = &(void __percpu *)(r%d)", 213 insn->code, insn->dst_reg, insn->src_reg); 214 } else if (BPF_SRC(insn->code) == BPF_X) { 215 verbose(cbs->private_data, "(%02x) %c%d %s %s%c%d", 216 insn->code, class == BPF_ALU ? 'w' : 'r', 217 insn->dst_reg, 218 is_sdiv_smod(insn) ? bpf_alu_sign_string[BPF_OP(insn->code) >> 4] 219 : bpf_alu_string[BPF_OP(insn->code) >> 4], 220 is_movsx(insn) ? bpf_movsx_string[(insn->off >> 3) - 1] : "", 221 class == BPF_ALU ? 'w' : 'r', 222 insn->src_reg); 223 } else { 224 verbose(cbs->private_data, "(%02x) %c%d %s %d", 225 insn->code, class == BPF_ALU ? 'w' : 'r', 226 insn->dst_reg, 227 is_sdiv_smod(insn) ? bpf_alu_sign_string[BPF_OP(insn->code) >> 4] 228 : bpf_alu_string[BPF_OP(insn->code) >> 4], 229 insn->imm); 230 } 231 } else if (class == BPF_STX) { 232 const char *probe_pfx = BPF_MODE(insn->code) == BPF_PROBE_ATOMIC ? "probe " : ""; 233 bool atomic = BPF_MODE(insn->code) == BPF_ATOMIC || 234 BPF_MODE(insn->code) == BPF_PROBE_ATOMIC; 235 236 if (BPF_MODE(insn->code) == BPF_MEM) 237 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = r%d", 238 insn->code, 239 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 240 insn->dst_reg, 241 insn->off, insn->src_reg); 242 else if (atomic && 243 (insn->imm == BPF_ADD || insn->imm == BPF_AND || 244 insn->imm == BPF_OR || insn->imm == BPF_XOR)) { 245 verbose(cbs->private_data, "(%02x) %slock *(%s *)(r%d %+d) %s r%d", 246 insn->code, probe_pfx, 247 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 248 insn->dst_reg, insn->off, 249 bpf_alu_string[BPF_OP(insn->imm) >> 4], 250 insn->src_reg); 251 } else if (atomic && 252 (insn->imm == (BPF_ADD | BPF_FETCH) || 253 insn->imm == (BPF_AND | BPF_FETCH) || 254 insn->imm == (BPF_OR | BPF_FETCH) || 255 insn->imm == (BPF_XOR | BPF_FETCH))) { 256 verbose(cbs->private_data, "(%02x) %sr%d = atomic%s_fetch_%s((%s *)(r%d %+d), r%d)", 257 insn->code, probe_pfx, insn->src_reg, 258 BPF_SIZE(insn->code) == BPF_DW ? "64" : "", 259 bpf_atomic_alu_string[BPF_OP(insn->imm) >> 4], 260 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 261 insn->dst_reg, insn->off, insn->src_reg); 262 } else if (atomic && insn->imm == BPF_CMPXCHG) { 263 verbose(cbs->private_data, "(%02x) %sr0 = atomic%s_cmpxchg((%s *)(r%d %+d), r0, r%d)", 264 insn->code, probe_pfx, 265 BPF_SIZE(insn->code) == BPF_DW ? "64" : "", 266 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 267 insn->dst_reg, insn->off, 268 insn->src_reg); 269 } else if (atomic && insn->imm == BPF_XCHG) { 270 verbose(cbs->private_data, "(%02x) %sr%d = atomic%s_xchg((%s *)(r%d %+d), r%d)", 271 insn->code, probe_pfx, insn->src_reg, 272 BPF_SIZE(insn->code) == BPF_DW ? "64" : "", 273 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 274 insn->dst_reg, insn->off, insn->src_reg); 275 } else if (atomic && insn->imm == BPF_LOAD_ACQ) { 276 verbose(cbs->private_data, "(%02x) %sr%d = load_acquire((%s *)(r%d %+d))", 277 insn->code, probe_pfx, insn->dst_reg, 278 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 279 insn->src_reg, insn->off); 280 } else if (atomic && insn->imm == BPF_STORE_REL) { 281 verbose(cbs->private_data, "(%02x) %sstore_release((%s *)(r%d %+d), r%d)", 282 insn->code, probe_pfx, 283 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 284 insn->dst_reg, insn->off, insn->src_reg); 285 } else { 286 verbose(cbs->private_data, "BUG_%02x", insn->code); 287 } 288 } else if (class == BPF_ST) { 289 if (BPF_MODE(insn->code) == BPF_MEM) { 290 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = %d", 291 insn->code, 292 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 293 insn->dst_reg, 294 insn->off, insn->imm); 295 } else if (BPF_MODE(insn->code) == 0xc0 /* BPF_NOSPEC, no UAPI */) { 296 verbose(cbs->private_data, "(%02x) nospec", insn->code); 297 } else { 298 verbose(cbs->private_data, "BUG_st_%02x", insn->code); 299 } 300 } else if (class == BPF_LDX) { 301 if ((BPF_MODE(insn->code) != BPF_MEM && BPF_MODE(insn->code) != BPF_MEMSX) || 302 (BPF_MODE(insn->code) == BPF_MEMSX && BPF_SIZE(insn->code) == BPF_DW)) { 303 verbose(cbs->private_data, "BUG_ldx_%02x", insn->code); 304 return; 305 } 306 verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)", 307 insn->code, insn->dst_reg, 308 BPF_MODE(insn->code) == BPF_MEM ? 309 bpf_ldst_string[BPF_SIZE(insn->code) >> 3] : 310 bpf_ldsx_string[BPF_SIZE(insn->code) >> 3], 311 insn->src_reg, insn->off); 312 } else if (class == BPF_LD) { 313 if (BPF_MODE(insn->code) == BPF_ABS) { 314 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[%d]", 315 insn->code, 316 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 317 insn->imm); 318 } else if (BPF_MODE(insn->code) == BPF_IND) { 319 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[r%d + %d]", 320 insn->code, 321 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 322 insn->src_reg, insn->imm); 323 } else if (BPF_MODE(insn->code) == BPF_IMM && 324 BPF_SIZE(insn->code) == BPF_DW) { 325 /* At this point, we already made sure that the second 326 * part of the ldimm64 insn is accessible. 327 */ 328 u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; 329 bool is_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD || 330 insn->src_reg == BPF_PSEUDO_MAP_VALUE || 331 insn->src_reg == BPF_PSEUDO_MAP_IDX || 332 insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE || 333 insn->src_reg == BPF_PSEUDO_BTF_ID; 334 char tmp[64]; 335 336 if (is_ptr && !allow_ptr_leaks) 337 imm = 0; 338 339 verbose(cbs->private_data, "(%02x) r%d = %s", 340 insn->code, insn->dst_reg, 341 __func_imm_name(cbs, insn, imm, 342 tmp, sizeof(tmp))); 343 } else { 344 verbose(cbs->private_data, "BUG_ld_%02x", insn->code); 345 return; 346 } 347 } else if (class == BPF_JMP32 || class == BPF_JMP) { 348 u8 opcode = BPF_OP(insn->code); 349 350 if (opcode == BPF_CALL) { 351 char tmp[64]; 352 353 if (insn->src_reg == BPF_PSEUDO_CALL) { 354 verbose(cbs->private_data, "(%02x) call pc%s", 355 insn->code, 356 __func_get_name(cbs, insn, 357 tmp, sizeof(tmp))); 358 } else { 359 strcpy(tmp, "unknown"); 360 verbose(cbs->private_data, "(%02x) call %s#%d", insn->code, 361 __func_get_name(cbs, insn, 362 tmp, sizeof(tmp)), 363 insn->imm); 364 } 365 } else if (insn->code == (BPF_JMP | BPF_JA)) { 366 verbose(cbs->private_data, "(%02x) goto pc%+d", 367 insn->code, insn->off); 368 } else if (insn->code == (BPF_JMP | BPF_JA | BPF_X)) { 369 verbose(cbs->private_data, "(%02x) gotox r%d", 370 insn->code, insn->dst_reg); 371 } else if (insn->code == (BPF_JMP | BPF_JCOND) && 372 insn->src_reg == BPF_MAY_GOTO) { 373 verbose(cbs->private_data, "(%02x) may_goto pc%+d", 374 insn->code, insn->off); 375 } else if (insn->code == (BPF_JMP32 | BPF_JA)) { 376 verbose(cbs->private_data, "(%02x) gotol pc%+d", 377 insn->code, insn->imm); 378 } else if (insn->code == (BPF_JMP | BPF_EXIT)) { 379 verbose(cbs->private_data, "(%02x) exit", insn->code); 380 } else if (BPF_SRC(insn->code) == BPF_X) { 381 verbose(cbs->private_data, 382 "(%02x) if %c%d %s %c%d goto pc%+d", 383 insn->code, class == BPF_JMP32 ? 'w' : 'r', 384 insn->dst_reg, 385 bpf_jmp_string[BPF_OP(insn->code) >> 4], 386 class == BPF_JMP32 ? 'w' : 'r', 387 insn->src_reg, insn->off); 388 } else { 389 verbose(cbs->private_data, 390 "(%02x) if %c%d %s 0x%x goto pc%+d", 391 insn->code, class == BPF_JMP32 ? 'w' : 'r', 392 insn->dst_reg, 393 bpf_jmp_string[BPF_OP(insn->code) >> 4], 394 (u32)insn->imm, insn->off); 395 } 396 } else { 397 verbose(cbs->private_data, "(%02x) %s", 398 insn->code, bpf_class_string[class]); 399 } 400 } 401