1 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com 2 * Copyright (c) 2016 Facebook 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of version 2 of the GNU General Public 6 * License as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, but 9 * WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 */ 13 14 #include <linux/bpf.h> 15 16 #include "disasm.h" 17 18 #define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x) 19 static const char * const func_id_str[] = { 20 __BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN) 21 }; 22 #undef __BPF_FUNC_STR_FN 23 24 static const char *__func_get_name(const struct bpf_insn_cbs *cbs, 25 const struct bpf_insn *insn, 26 char *buff, size_t len) 27 { 28 BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID); 29 30 if (insn->src_reg != BPF_PSEUDO_CALL && 31 insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID && 32 func_id_str[insn->imm]) 33 return func_id_str[insn->imm]; 34 35 if (cbs && cbs->cb_call) 36 return cbs->cb_call(cbs->private_data, insn); 37 38 if (insn->src_reg == BPF_PSEUDO_CALL) 39 snprintf(buff, len, "%+d", insn->imm); 40 41 return buff; 42 } 43 44 static const char *__func_imm_name(const struct bpf_insn_cbs *cbs, 45 const struct bpf_insn *insn, 46 u64 full_imm, char *buff, size_t len) 47 { 48 if (cbs && cbs->cb_imm) 49 return cbs->cb_imm(cbs->private_data, insn, full_imm); 50 51 snprintf(buff, len, "0x%llx", (unsigned long long)full_imm); 52 return buff; 53 } 54 55 const char *func_id_name(int id) 56 { 57 if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id]) 58 return func_id_str[id]; 59 else 60 return "unknown"; 61 } 62 63 const char *const bpf_class_string[8] = { 64 [BPF_LD] = "ld", 65 [BPF_LDX] = "ldx", 66 [BPF_ST] = "st", 67 [BPF_STX] = "stx", 68 [BPF_ALU] = "alu", 69 [BPF_JMP] = "jmp", 70 [BPF_RET] = "BUG", 71 [BPF_ALU64] = "alu64", 72 }; 73 74 const char *const bpf_alu_string[16] = { 75 [BPF_ADD >> 4] = "+=", 76 [BPF_SUB >> 4] = "-=", 77 [BPF_MUL >> 4] = "*=", 78 [BPF_DIV >> 4] = "/=", 79 [BPF_OR >> 4] = "|=", 80 [BPF_AND >> 4] = "&=", 81 [BPF_LSH >> 4] = "<<=", 82 [BPF_RSH >> 4] = ">>=", 83 [BPF_NEG >> 4] = "neg", 84 [BPF_MOD >> 4] = "%=", 85 [BPF_XOR >> 4] = "^=", 86 [BPF_MOV >> 4] = "=", 87 [BPF_ARSH >> 4] = "s>>=", 88 [BPF_END >> 4] = "endian", 89 }; 90 91 static const char *const bpf_ldst_string[] = { 92 [BPF_W >> 3] = "u32", 93 [BPF_H >> 3] = "u16", 94 [BPF_B >> 3] = "u8", 95 [BPF_DW >> 3] = "u64", 96 }; 97 98 static const char *const bpf_jmp_string[16] = { 99 [BPF_JA >> 4] = "jmp", 100 [BPF_JEQ >> 4] = "==", 101 [BPF_JGT >> 4] = ">", 102 [BPF_JLT >> 4] = "<", 103 [BPF_JGE >> 4] = ">=", 104 [BPF_JLE >> 4] = "<=", 105 [BPF_JSET >> 4] = "&", 106 [BPF_JNE >> 4] = "!=", 107 [BPF_JSGT >> 4] = "s>", 108 [BPF_JSLT >> 4] = "s<", 109 [BPF_JSGE >> 4] = "s>=", 110 [BPF_JSLE >> 4] = "s<=", 111 [BPF_CALL >> 4] = "call", 112 [BPF_EXIT >> 4] = "exit", 113 }; 114 115 static void print_bpf_end_insn(bpf_insn_print_t verbose, 116 void *private_data, 117 const struct bpf_insn *insn) 118 { 119 verbose(private_data, "(%02x) r%d = %s%d r%d\n", 120 insn->code, insn->dst_reg, 121 BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le", 122 insn->imm, insn->dst_reg); 123 } 124 125 void print_bpf_insn(const struct bpf_insn_cbs *cbs, 126 const struct bpf_insn *insn, 127 bool allow_ptr_leaks) 128 { 129 const bpf_insn_print_t verbose = cbs->cb_print; 130 u8 class = BPF_CLASS(insn->code); 131 132 if (class == BPF_ALU || class == BPF_ALU64) { 133 if (BPF_OP(insn->code) == BPF_END) { 134 if (class == BPF_ALU64) 135 verbose(cbs->private_data, "BUG_alu64_%02x\n", insn->code); 136 else 137 print_bpf_end_insn(verbose, cbs->private_data, insn); 138 } else if (BPF_OP(insn->code) == BPF_NEG) { 139 verbose(cbs->private_data, "(%02x) r%d = %s-r%d\n", 140 insn->code, insn->dst_reg, 141 class == BPF_ALU ? "(u32) " : "", 142 insn->dst_reg); 143 } else if (BPF_SRC(insn->code) == BPF_X) { 144 verbose(cbs->private_data, "(%02x) %sr%d %s %sr%d\n", 145 insn->code, class == BPF_ALU ? "(u32) " : "", 146 insn->dst_reg, 147 bpf_alu_string[BPF_OP(insn->code) >> 4], 148 class == BPF_ALU ? "(u32) " : "", 149 insn->src_reg); 150 } else { 151 verbose(cbs->private_data, "(%02x) %sr%d %s %s%d\n", 152 insn->code, class == BPF_ALU ? "(u32) " : "", 153 insn->dst_reg, 154 bpf_alu_string[BPF_OP(insn->code) >> 4], 155 class == BPF_ALU ? "(u32) " : "", 156 insn->imm); 157 } 158 } else if (class == BPF_STX) { 159 if (BPF_MODE(insn->code) == BPF_MEM) 160 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = r%d\n", 161 insn->code, 162 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 163 insn->dst_reg, 164 insn->off, insn->src_reg); 165 else if (BPF_MODE(insn->code) == BPF_XADD) 166 verbose(cbs->private_data, "(%02x) lock *(%s *)(r%d %+d) += r%d\n", 167 insn->code, 168 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 169 insn->dst_reg, insn->off, 170 insn->src_reg); 171 else 172 verbose(cbs->private_data, "BUG_%02x\n", insn->code); 173 } else if (class == BPF_ST) { 174 if (BPF_MODE(insn->code) != BPF_MEM) { 175 verbose(cbs->private_data, "BUG_st_%02x\n", insn->code); 176 return; 177 } 178 verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = %d\n", 179 insn->code, 180 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 181 insn->dst_reg, 182 insn->off, insn->imm); 183 } else if (class == BPF_LDX) { 184 if (BPF_MODE(insn->code) != BPF_MEM) { 185 verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code); 186 return; 187 } 188 verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)\n", 189 insn->code, insn->dst_reg, 190 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 191 insn->src_reg, insn->off); 192 } else if (class == BPF_LD) { 193 if (BPF_MODE(insn->code) == BPF_ABS) { 194 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[%d]\n", 195 insn->code, 196 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 197 insn->imm); 198 } else if (BPF_MODE(insn->code) == BPF_IND) { 199 verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[r%d + %d]\n", 200 insn->code, 201 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 202 insn->src_reg, insn->imm); 203 } else if (BPF_MODE(insn->code) == BPF_IMM && 204 BPF_SIZE(insn->code) == BPF_DW) { 205 /* At this point, we already made sure that the second 206 * part of the ldimm64 insn is accessible. 207 */ 208 u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; 209 bool map_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD; 210 char tmp[64]; 211 212 if (map_ptr && !allow_ptr_leaks) 213 imm = 0; 214 215 verbose(cbs->private_data, "(%02x) r%d = %s\n", 216 insn->code, insn->dst_reg, 217 __func_imm_name(cbs, insn, imm, 218 tmp, sizeof(tmp))); 219 } else { 220 verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code); 221 return; 222 } 223 } else if (class == BPF_JMP) { 224 u8 opcode = BPF_OP(insn->code); 225 226 if (opcode == BPF_CALL) { 227 char tmp[64]; 228 229 if (insn->src_reg == BPF_PSEUDO_CALL) { 230 verbose(cbs->private_data, "(%02x) call pc%s\n", 231 insn->code, 232 __func_get_name(cbs, insn, 233 tmp, sizeof(tmp))); 234 } else { 235 strcpy(tmp, "unknown"); 236 verbose(cbs->private_data, "(%02x) call %s#%d\n", insn->code, 237 __func_get_name(cbs, insn, 238 tmp, sizeof(tmp)), 239 insn->imm); 240 } 241 } else if (insn->code == (BPF_JMP | BPF_JA)) { 242 verbose(cbs->private_data, "(%02x) goto pc%+d\n", 243 insn->code, insn->off); 244 } else if (insn->code == (BPF_JMP | BPF_EXIT)) { 245 verbose(cbs->private_data, "(%02x) exit\n", insn->code); 246 } else if (BPF_SRC(insn->code) == BPF_X) { 247 verbose(cbs->private_data, "(%02x) if r%d %s r%d goto pc%+d\n", 248 insn->code, insn->dst_reg, 249 bpf_jmp_string[BPF_OP(insn->code) >> 4], 250 insn->src_reg, insn->off); 251 } else { 252 verbose(cbs->private_data, "(%02x) if r%d %s 0x%x goto pc%+d\n", 253 insn->code, insn->dst_reg, 254 bpf_jmp_string[BPF_OP(insn->code) >> 4], 255 insn->imm, insn->off); 256 } 257 } else { 258 verbose(cbs->private_data, "(%02x) %s\n", 259 insn->code, bpf_class_string[class]); 260 } 261 } 262