163 lines
3.3 KiB
C
163 lines
3.3 KiB
C
|
/*
|
||
|
|
* 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);
|
||
|
|
}
|