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 const char *func_id_name(int id) 25 { 26 BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID); 27 28 if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id]) 29 return func_id_str[id]; 30 else 31 return "unknown"; 32 } 33 34 const char *const bpf_class_string[8] = { 35 [BPF_LD] = "ld", 36 [BPF_LDX] = "ldx", 37 [BPF_ST] = "st", 38 [BPF_STX] = "stx", 39 [BPF_ALU] = "alu", 40 [BPF_JMP] = "jmp", 41 [BPF_RET] = "BUG", 42 [BPF_ALU64] = "alu64", 43 }; 44 45 const char *const bpf_alu_string[16] = { 46 [BPF_ADD >> 4] = "+=", 47 [BPF_SUB >> 4] = "-=", 48 [BPF_MUL >> 4] = "*=", 49 [BPF_DIV >> 4] = "/=", 50 [BPF_OR >> 4] = "|=", 51 [BPF_AND >> 4] = "&=", 52 [BPF_LSH >> 4] = "<<=", 53 [BPF_RSH >> 4] = ">>=", 54 [BPF_NEG >> 4] = "neg", 55 [BPF_MOD >> 4] = "%=", 56 [BPF_XOR >> 4] = "^=", 57 [BPF_MOV >> 4] = "=", 58 [BPF_ARSH >> 4] = "s>>=", 59 [BPF_END >> 4] = "endian", 60 }; 61 62 static const char *const bpf_ldst_string[] = { 63 [BPF_W >> 3] = "u32", 64 [BPF_H >> 3] = "u16", 65 [BPF_B >> 3] = "u8", 66 [BPF_DW >> 3] = "u64", 67 }; 68 69 static const char *const bpf_jmp_string[16] = { 70 [BPF_JA >> 4] = "jmp", 71 [BPF_JEQ >> 4] = "==", 72 [BPF_JGT >> 4] = ">", 73 [BPF_JLT >> 4] = "<", 74 [BPF_JGE >> 4] = ">=", 75 [BPF_JLE >> 4] = "<=", 76 [BPF_JSET >> 4] = "&", 77 [BPF_JNE >> 4] = "!=", 78 [BPF_JSGT >> 4] = "s>", 79 [BPF_JSLT >> 4] = "s<", 80 [BPF_JSGE >> 4] = "s>=", 81 [BPF_JSLE >> 4] = "s<=", 82 [BPF_CALL >> 4] = "call", 83 [BPF_EXIT >> 4] = "exit", 84 }; 85 86 static void print_bpf_end_insn(bpf_insn_print_cb verbose, 87 struct bpf_verifier_env *env, 88 const struct bpf_insn *insn) 89 { 90 verbose(env, "(%02x) r%d = %s%d r%d\n", insn->code, insn->dst_reg, 91 BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le", 92 insn->imm, insn->dst_reg); 93 } 94 95 void print_bpf_insn(bpf_insn_print_cb verbose, struct bpf_verifier_env *env, 96 const struct bpf_insn *insn, bool allow_ptr_leaks) 97 { 98 u8 class = BPF_CLASS(insn->code); 99 100 if (class == BPF_ALU || class == BPF_ALU64) { 101 if (BPF_OP(insn->code) == BPF_END) { 102 if (class == BPF_ALU64) 103 verbose(env, "BUG_alu64_%02x\n", insn->code); 104 else 105 print_bpf_end_insn(verbose, env, insn); 106 } else if (BPF_OP(insn->code) == BPF_NEG) { 107 verbose(env, "(%02x) r%d = %s-r%d\n", 108 insn->code, insn->dst_reg, 109 class == BPF_ALU ? "(u32) " : "", 110 insn->dst_reg); 111 } else if (BPF_SRC(insn->code) == BPF_X) { 112 verbose(env, "(%02x) %sr%d %s %sr%d\n", 113 insn->code, class == BPF_ALU ? "(u32) " : "", 114 insn->dst_reg, 115 bpf_alu_string[BPF_OP(insn->code) >> 4], 116 class == BPF_ALU ? "(u32) " : "", 117 insn->src_reg); 118 } else { 119 verbose(env, "(%02x) %sr%d %s %s%d\n", 120 insn->code, class == BPF_ALU ? "(u32) " : "", 121 insn->dst_reg, 122 bpf_alu_string[BPF_OP(insn->code) >> 4], 123 class == BPF_ALU ? "(u32) " : "", 124 insn->imm); 125 } 126 } else if (class == BPF_STX) { 127 if (BPF_MODE(insn->code) == BPF_MEM) 128 verbose(env, "(%02x) *(%s *)(r%d %+d) = r%d\n", 129 insn->code, 130 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 131 insn->dst_reg, 132 insn->off, insn->src_reg); 133 else if (BPF_MODE(insn->code) == BPF_XADD) 134 verbose(env, "(%02x) lock *(%s *)(r%d %+d) += r%d\n", 135 insn->code, 136 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 137 insn->dst_reg, insn->off, 138 insn->src_reg); 139 else 140 verbose(env, "BUG_%02x\n", insn->code); 141 } else if (class == BPF_ST) { 142 if (BPF_MODE(insn->code) != BPF_MEM) { 143 verbose(env, "BUG_st_%02x\n", insn->code); 144 return; 145 } 146 verbose(env, "(%02x) *(%s *)(r%d %+d) = %d\n", 147 insn->code, 148 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 149 insn->dst_reg, 150 insn->off, insn->imm); 151 } else if (class == BPF_LDX) { 152 if (BPF_MODE(insn->code) != BPF_MEM) { 153 verbose(env, "BUG_ldx_%02x\n", insn->code); 154 return; 155 } 156 verbose(env, "(%02x) r%d = *(%s *)(r%d %+d)\n", 157 insn->code, insn->dst_reg, 158 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 159 insn->src_reg, insn->off); 160 } else if (class == BPF_LD) { 161 if (BPF_MODE(insn->code) == BPF_ABS) { 162 verbose(env, "(%02x) r0 = *(%s *)skb[%d]\n", 163 insn->code, 164 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 165 insn->imm); 166 } else if (BPF_MODE(insn->code) == BPF_IND) { 167 verbose(env, "(%02x) r0 = *(%s *)skb[r%d + %d]\n", 168 insn->code, 169 bpf_ldst_string[BPF_SIZE(insn->code) >> 3], 170 insn->src_reg, insn->imm); 171 } else if (BPF_MODE(insn->code) == BPF_IMM && 172 BPF_SIZE(insn->code) == BPF_DW) { 173 /* At this point, we already made sure that the second 174 * part of the ldimm64 insn is accessible. 175 */ 176 u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; 177 bool map_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD; 178 179 if (map_ptr && !allow_ptr_leaks) 180 imm = 0; 181 182 verbose(env, "(%02x) r%d = 0x%llx\n", insn->code, 183 insn->dst_reg, (unsigned long long)imm); 184 } else { 185 verbose(env, "BUG_ld_%02x\n", insn->code); 186 return; 187 } 188 } else if (class == BPF_JMP) { 189 u8 opcode = BPF_OP(insn->code); 190 191 if (opcode == BPF_CALL) { 192 verbose(env, "(%02x) call %s#%d\n", insn->code, 193 func_id_name(insn->imm), insn->imm); 194 } else if (insn->code == (BPF_JMP | BPF_JA)) { 195 verbose(env, "(%02x) goto pc%+d\n", 196 insn->code, insn->off); 197 } else if (insn->code == (BPF_JMP | BPF_EXIT)) { 198 verbose(env, "(%02x) exit\n", insn->code); 199 } else if (BPF_SRC(insn->code) == BPF_X) { 200 verbose(env, "(%02x) if r%d %s r%d goto pc%+d\n", 201 insn->code, insn->dst_reg, 202 bpf_jmp_string[BPF_OP(insn->code) >> 4], 203 insn->src_reg, insn->off); 204 } else { 205 verbose(env, "(%02x) if r%d %s 0x%x goto pc%+d\n", 206 insn->code, insn->dst_reg, 207 bpf_jmp_string[BPF_OP(insn->code) >> 4], 208 insn->imm, insn->off); 209 } 210 } else { 211 verbose(env, "(%02x) %s\n", 212 insn->code, bpf_class_string[class]); 213 } 214 } 215