1 // SPDX-License-Identifier: GPL-2.0-only 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 #define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x) 11 static const char * const func_id_str[] = { 12 __BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN) 13 }; 14 #undef __BPF_FUNC_STR_FN 15 16 static const char *__func_get_name(const struct bpf_insn_cbs *cbs, 17 const struct bpf_insn *insn, 18 char *buff, size_t len) 19 { 20 BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID); 21 22 if (insn->src_reg != BPF_PSEUDO_CALL && 23 insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID && 24 func_id_str[insn->imm]) 25 return func_id_str[insn->imm]; 26 27 if (cbs && cbs->cb_call) 28 return cbs->cb_call(cbs->private_data, insn); 29 30 if (insn->src_reg == BPF_PSEUDO_CALL) 31 snprintf(buff, len, "%+d", insn->imm); 32 33 return buff; 34 } 35 36 static const char *__func_imm_name(const struct bpf_insn_cbs *cbs, 37 const struct bpf_insn *insn, 38 u64 full_imm, char *buff, size_t len) 39 { 40 if (cbs && cbs->cb_imm) 41 return cbs->cb_imm(cbs->private_data, insn, full_imm); 42 43 snprintf(buff, len, "0x%llx", (unsigned long long)full_imm); 44 return buff; 45 } 46 47 const char *func_id_name(int id) 48 { 49 if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id]) 50 return func_id_str[id]; 51 else 52 return "unknown"; 53 } 54 55 const char *const bpf_class_string[8] = { 56 [BPF_LD] = "ld", 57 [BPF_LDX] = "ldx", 58 [BPF_ST] = "st", 59 [BPF_STX] = "stx", 60 [BPF_ALU] = "alu", 61 [BPF_JMP] = "jmp", 62 [BPF_JMP32] = "jmp32", 63 [BPF_ALU64] = "alu64", 64 }; 65 66 const char *const bpf_alu_string[16] = { 67 [BPF_ADD >> 4] = "+=", 68 [BPF_SUB >> 4] = "-=", 69 [BPF_MUL >> 4] = "*=", 70 [BPF_DIV >> 4] = "/=", 71 [BPF_OR >> 4] = "|=", 72 [BPF_AND >> 4] = "&=", 73 [BPF_LSH >> 4] = "<<=", 74 [BPF_RSH >> 4] = ">>=", 75 [BPF_NEG >> 4] = "neg", 76 [BPF_MOD >> 4] = "%=", 77 [BPF_XOR >> 4] = "^=", 78 [BPF_MOV >> 4] = "=", 79 [BPF_ARSH >> 4] = "s>>=", 80 [BPF_END >> 4] = "endian", 81 }; 82 83 static const char *const bpf_ldst_string[] = { 84 [BPF_W >> 3] = "u32", 85 [BPF_H >> 3] = "u16", 86 [BPF_B >> 3] = "u8", 87 [BPF_DW >> 3] = "u64", 88 }; 89 90 static const char *const bpf_jmp_string[16] = { 91 [BPF_JA >> 4] = "jmp", 92 [BPF_JEQ >> 4] = "==", 93 [BPF_JGT >> 4] = ">", 94 [BPF_JLT >> 4] = "<", 95 [BPF_JGE >> 4] = ">=", 96 [BPF_JLE >> 4] = "<=", 97 [BPF_JSET >> 4] = "&", 98 [BPF_JNE >> 4] = "!=", 99 [BPF_JSGT >> 4] = "s>", 100 [BPF_JSLT >> 4] = "s<", 101 [BPF_JSGE >> 4] = "s>=", 102 [BPF_JSLE >> 4] = "s<=", 103 [BPF_CALL >> 4] = "call", 104 [BPF_EXIT >> 4] = "exit", 105 }; 106 107 static void print_bpf_end_insn(bpf_insn_print_t verbose, 108 void *private_data, 109 const struct bpf_insn *insn) 110 { 111 verbose(private_data, "(%02x) r%d = %s%d r%d\n", 112 insn->code, insn->dst_reg, 113 BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le", 114 insn->imm, insn->dst_reg); 115 } 116 117 void print_bpf_insn(const struct bpf_insn_cbs *cbs, 118 const struct bpf_insn *insn, 119 bool allow_ptr_leaks) 120 { 121 const bpf_insn_print_t verbose = cbs->cb_print; 122 u8 class = BPF_CLASS(insn->code); 123 124 if (class == BPF_ALU || class == BPF_ALU64) { 125 if (BPF_OP(insn->code) == BPF_END) { 126 if (class == BPF_ALU64) 127 verbose(cbs->private_data, "BUG_alu64_%02x\n", insn->code); 128 else 129 print_bpf_end_insn(verbose, cbs->private_data, insn); 130 } else if (BPF_OP(insn->code) == BPF_NEG) { 131 verbose(cbs->private_data, "(%02x) %c%d = -%c%d\n", 132 insn->code, class == BPF_ALU ? 'w' : 'r', 133 insn->dst_reg, class == BPF_ALU ? 'w' : 'r', 134 insn->dst_reg); 135 } else if (BPF_SRC(insn->code) == BPF_X) { 136 verbose(cbs->private_data, "(%02x) %c%d %s %c%d\n", 137 insn->code, class == BPF_ALU ? 'w' : 'r', 138 insn->dst_reg, 139 bpf_alu_string[BPF_OP(insn->code) >> 4], 140 class == BPF_ALU ? 'w' : 'r', 141 insn->src_reg); 142 } else { 143 verbose(cbs->private_data, "(%02x) %c%d %s %d\n", 144 insn->code, class == BPF_ALU ? 'w' : 'r', 145 insn->dst_reg, 146 bpf_alu_string[BPF_OP(insn->code) >> 4], 147 insn->imm); 148 } 149 } else if (class == BPF_STX) { 150 if (BPF_MODE(insn->code) == BPF_MEM) 151 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = r%d\n", 152 insn->code, 153 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 154 insn->dst_reg, 155 insn->off, insn->src_reg); 156 else if (BPF_MODE(insn->code) == BPF_ATOMIC && 157 insn->imm == BPF_ADD) { 158 verbose(cbs->private_data, "(%02x) lock *(%s *)(r%d %+d) += r%d\n", 159 insn->code, 160 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 161 insn->dst_reg, insn->off, 162 insn->src_reg); 163 } else { 164 verbose(cbs->private_data, "BUG_%02x\n", insn->code); 165 } 166 } else if (class == BPF_ST) { 167 if (BPF_MODE(insn->code) != BPF_MEM) { 168 verbose(cbs->private_data, "BUG_st_%02x\n", insn->code); 169 return; 170 } 171 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = %d\n", 172 insn->code, 173 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 174 insn->dst_reg, 175 insn->off, insn->imm); 176 } else if (class == BPF_LDX) { 177 if (BPF_MODE(insn->code) != BPF_MEM) { 178 verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code); 179 return; 180 } 181 verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)\n", 182 insn->code, insn->dst_reg, 183 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 184 insn->src_reg, insn->off); 185 } else if (class == BPF_LD) { 186 if (BPF_MODE(insn->code) == BPF_ABS) { 187 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[%d]\n", 188 insn->code, 189 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 190 insn->imm); 191 } else if (BPF_MODE(insn->code) == BPF_IND) { 192 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[r%d + %d]\n", 193 insn->code, 194 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 195 insn->src_reg, insn->imm); 196 } else if (BPF_MODE(insn->code) == BPF_IMM && 197 BPF_SIZE(insn->code) == BPF_DW) { 198 /* At this point, we already made sure that the second 199 * part of the ldimm64 insn is accessible. 200 */ 201 u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; 202 bool is_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD || 203 insn->src_reg == BPF_PSEUDO_MAP_VALUE; 204 char tmp[64]; 205 206 if (is_ptr && !allow_ptr_leaks) 207 imm = 0; 208 209 verbose(cbs->private_data, "(%02x) r%d = %s\n", 210 insn->code, insn->dst_reg, 211 __func_imm_name(cbs, insn, imm, 212 tmp, sizeof(tmp))); 213 } else { 214 verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code); 215 return; 216 } 217 } else if (class == BPF_JMP32 || class == BPF_JMP) { 218 u8 opcode = BPF_OP(insn->code); 219 220 if (opcode == BPF_CALL) { 221 char tmp[64]; 222 223 if (insn->src_reg == BPF_PSEUDO_CALL) { 224 verbose(cbs->private_data, "(%02x) call pc%s\n", 225 insn->code, 226 __func_get_name(cbs, insn, 227 tmp, sizeof(tmp))); 228 } else { 229 strcpy(tmp, "unknown"); 230 verbose(cbs->private_data, "(%02x) call %s#%d\n", insn->code, 231 __func_get_name(cbs, insn, 232 tmp, sizeof(tmp)), 233 insn->imm); 234 } 235 } else if (insn->code == (BPF_JMP | BPF_JA)) { 236 verbose(cbs->private_data, "(%02x) goto pc%+d\n", 237 insn->code, insn->off); 238 } else if (insn->code == (BPF_JMP | BPF_EXIT)) { 239 verbose(cbs->private_data, "(%02x) exit\n", insn->code); 240 } else if (BPF_SRC(insn->code) == BPF_X) { 241 verbose(cbs->private_data, 242 "(%02x) if %c%d %s %c%d goto pc%+d\n", 243 insn->code, class == BPF_JMP32 ? 'w' : 'r', 244 insn->dst_reg, 245 bpf_jmp_string[BPF_OP(insn->code) >> 4], 246 class == BPF_JMP32 ? 'w' : 'r', 247 insn->src_reg, insn->off); 248 } else { 249 verbose(cbs->private_data, 250 "(%02x) if %c%d %s 0x%x goto pc%+d\n", 251 insn->code, class == BPF_JMP32 ? 'w' : 'r', 252 insn->dst_reg, 253 bpf_jmp_string[BPF_OP(insn->code) >> 4], 254 insn->imm, insn->off); 255 } 256 } else { 257 verbose(cbs->private_data, "(%02x) %s\n", 258 insn->code, bpf_class_string[class]); 259 } 260 } 261