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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 | /* * Based on: * * Minimal BPF JIT image disassembler * * Disassembles BPF JIT compiler emitted opcodes back to asm insn's for * debugging or verification purposes. * * Copyright 2013 Daniel Borkmann <daniel@iogearbox.net> * Licensed under the GNU General Public License, version 2.0 (GPLv2) */ #include <stdarg.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <assert.h> #include <unistd.h> #include <string.h> #include <bfd.h> #include <dis-asm.h> #include <sys/types.h> #include <sys/stat.h> #include <limits.h> #include "json_writer.h" #include "main.h" static void get_exec_path(char *tpath, size_t size) { ssize_t len; char *path; snprintf(tpath, size, "/proc/%d/exe", (int) getpid()); tpath[size - 1] = 0; path = strdup(tpath); assert(path); len = readlink(path, tpath, size - 1); assert(len > 0); tpath[len] = 0; free(path); } static int oper_count; static int fprintf_json(void *out, const char *fmt, ...) { va_list ap; char *s; va_start(ap, fmt); if (!oper_count) { int i; s = va_arg(ap, char *); /* Strip trailing spaces */ i = strlen(s) - 1; while (s[i] == ' ') s[i--] = '\0'; jsonw_string_field(json_wtr, "operation", s); jsonw_name(json_wtr, "operands"); jsonw_start_array(json_wtr); oper_count++; } else if (!strcmp(fmt, ",")) { /* Skip */ } else { s = va_arg(ap, char *); jsonw_string(json_wtr, s); oper_count++; } va_end(ap); return 0; } void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes) { disassembler_ftype disassemble; struct disassemble_info info; int count, i, pc = 0; char tpath[PATH_MAX]; bfd *bfdf; if (!len) return; memset(tpath, 0, sizeof(tpath)); get_exec_path(tpath, sizeof(tpath)); bfdf = bfd_openr(tpath, NULL); assert(bfdf); assert(bfd_check_format(bfdf, bfd_object)); if (json_output) init_disassemble_info(&info, stdout, (fprintf_ftype) fprintf_json); else init_disassemble_info(&info, stdout, (fprintf_ftype) fprintf); info.arch = bfd_get_arch(bfdf); info.mach = bfd_get_mach(bfdf); info.buffer = image; info.buffer_length = len; disassemble_init_for_target(&info); disassemble = disassembler(bfdf); assert(disassemble); if (json_output) jsonw_start_array(json_wtr); do { if (json_output) { jsonw_start_object(json_wtr); oper_count = 0; jsonw_name(json_wtr, "pc"); jsonw_printf(json_wtr, "\"0x%x\"", pc); } else { printf("%4x:\t", pc); } count = disassemble(pc, &info); if (json_output) { /* Operand array, was started in fprintf_json. Before * that, make sure we have a _null_ value if no operand * other than operation code was present. */ if (oper_count == 1) jsonw_null(json_wtr); jsonw_end_array(json_wtr); } if (opcodes) { if (json_output) { jsonw_name(json_wtr, "opcodes"); jsonw_start_array(json_wtr); for (i = 0; i < count; ++i) jsonw_printf(json_wtr, "\"0x%02hhx\"", (uint8_t)image[pc + i]); jsonw_end_array(json_wtr); } else { printf("\n\t"); for (i = 0; i < count; ++i) printf("%02x ", (uint8_t)image[pc + i]); } } if (json_output) jsonw_end_object(json_wtr); else printf("\n"); pc += count; } while (count > 0 && pc < len); if (json_output) jsonw_end_array(json_wtr); bfd_close(bfdf); } |