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/*
* The Sleuth Kit
*
* Brian Carrier [carrier <at> sleuthkit [dot] org]
* Copyright (c) 2004 Brian Carrier. All rights reserved
*
* sigfind
*
* This software is distributed under the Common Public License 1.0
*/
#include "tsk/tsk_tools_i.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <limits.h>
#include <errno.h>
extern char *progname;
void
usage()
{
fprintf(stderr,
"%s [-b bsize] [-o offset] [-t template] [-lV] [hex_signature] file\n",
progname);
fprintf(stderr, "\t-b bsize: Give block size (default 512)\n");
fprintf(stderr,
"\t-o offset: Give offset into block where signature should exist (default 0)\n");
fprintf(stderr, "\t-l: Signature will be little endian in image\n");
fprintf(stderr, "\t-V: Version\n");
fprintf(stderr,
"\t-t template: The name of a data structure template:\n");
fprintf(stderr,
"\t\tdospart, ext2, ext3, ext4, fat, hfs, hfs+, ntfs, ufs1, ufs2\n");
exit(1);
}
// @@@ Should have a big endian flag as well
int
main(int argc, char **argv)
{
int ch;
uint8_t sig[4] = { 0, 0, 0, 0 };
uint8_t block[1024];
char **err = NULL;
TSK_IMG_INFO *img_info;
TSK_OFF_T cur_offset;
int sig_offset = 0, rel_offset = 0;
int read_size, bs = 512;
TSK_OFF_T i, prev_hit;
int sig_size = 0;
uint8_t lit_end = 0;
int sig_print = 0;
progname = argv[0];
while ((ch = getopt(argc, argv, "b:lo:t:V")) > 0) {
switch (ch) {
case 'b':
bs = strtol(optarg, err, 10);
if ((bs == 0) || (errno == EINVAL)) {
fprintf(stderr, "Error converting block size: %s\n",
optarg);
exit(1);
}
if (bs % 512) {
fprintf(stderr, "Invalid block size\n");
exit(1);
}
break;
case 'l':
lit_end = 1;
break;
case 'o':
/* Get the sig_offset in the sector */
sig_offset = strtol(optarg, err, 10);
if ((sig_offset == 0) || (errno == EINVAL)) {
fprintf(stderr, "Error converting offset value: %s\n",
optarg);
exit(1);
}
break;
case 't':
if ((strcmp(optarg, "ext2") == 0) ||
(strcmp(optarg, "ext3") == 0) ||
(strcmp(optarg, "ext4") == 0)) {
lit_end = 1;
sig[0] = 0x53;
sig[1] = 0xef;
sig_size = 2;
sig_offset = 56;
bs = 512;
}
else if ((strcmp(optarg, "dospart") == 0) ||
(strcmp(optarg, "fat") == 0) ||
(strcmp(optarg, "ntfs") == 0)) {
lit_end = 1;
sig[0] = 0x55;
sig[1] = 0xaa;
sig_size = 2;
sig_offset = 510;
bs = 512;
}
else if (strcmp(optarg, "ufs1") == 0) {
lit_end = 1;
sig[0] = 0x54;
sig[1] = 0x19;
sig[2] = 0x01;
sig[3] = 0x00;
sig_size = 4;
/* Located 1372 into SB */
sig_offset = 348;
bs = 512;
}
else if (strcmp(optarg, "ufs2") == 0) {
lit_end = 1;
sig[0] = 0x19;
sig[1] = 0x01;
sig[2] = 0x54;
sig[3] = 0x19;
sig_size = 4;
/* Located 1372 into SB */
sig_offset = 348;
bs = 512;
}
else if (strcmp(optarg, "hfs+") == 0) {
lit_end = 1;
sig[0] = 0x48;
sig[1] = 0x2b;
sig[2] = 0x00;
sig[3] = 0x04;
sig_size = 4;
/* Located 1024 into image */
sig_offset = 0;
bs = 512;
}
else if (strcmp(optarg, "hfs") == 0) {
lit_end = 1;
sig[0] = 0x42;
sig[1] = 0x44;
sig_size = 2;
/* Located 1024 into image */
sig_offset = 0;
bs = 512;
}
else {
fprintf(stderr, "Invalid template\n");
exit(1);
}
break;
case 'V':
tsk_version_print(stdout);
exit(0);
default:
usage();
}
}
/* If we didn't get a template then check the cmd line */
if (sig_size == 0) {
if (optind + 1 > argc) {
usage();
}
/* Get the hex value */
sig_size = 0;
for (i = 0; i < 9; i++) {
uint8_t tmp;
tmp = argv[optind][i];
if (tmp == 0) {
if (i % 2) {
fprintf(stderr,
"Invaild signature - full bytes only\n");
exit(1);
}
break;
}
/* Digit */
if ((tmp >= 0x30) && (tmp <= 0x39)) {
tmp -= 0x30;
}
/* lowercase a-f */
else if ((tmp >= 0x61) && (tmp <= 0x66)) {
tmp -= 0x57;
}
else if ((tmp >= 0x41) && (tmp <= 0x46)) {
tmp -= 0x37;
}
else {
fprintf(stderr, "Invalid signature value: %c\n", tmp);
exit(1);
}
/* big nibble */
if (0 == (i % 2)) {
sig[sig_size] = 16 * tmp;
}
else {
sig[sig_size] += tmp;
sig_size++;
}
}
optind++;
/* Check the signature length */
if (i == 9) {
fprintf(stderr,
"Error: Maximum supported signature size is 4 bytes\n");
exit(1);
}
/* Need to switch order */
if (lit_end) {
uint8_t tmp;
if (sig_size == 2) {
tmp = sig[1];
sig[1] = sig[0];
sig[0] = tmp;
}
else if (sig_size == 3) {
tmp = sig[2];
sig[2] = sig[0];
sig[0] = tmp;
}
else if (sig_size == 4) {
tmp = sig[3];
sig[3] = sig[0];
sig[0] = tmp;
tmp = sig[2];
sig[2] = sig[1];
sig[1] = tmp;
}
}
}
if (sig_offset < 0) {
fprintf(stderr, "Error: negative signature offset\n");
exit(1);
}
/* Check that the signature and offset are not larger than a block */
if ((sig_offset + sig_size) > bs) {
fprintf(stderr,
"Error: The offset and signature sizes are greater than the block size\n");
exit(1);
}
read_size = 512;
/* If our signature crosses the 512 boundary, then read 1k at a time */
if ((sig_offset / 512) != ((sig_offset + sig_size - 1) / 512)) {
read_size = 1024;
}
/* Get the image */
if (optind + 1 != argc) {
usage();
}
if ((img_info =
tsk_img_open_utf8_sing(argv[optind],
TSK_IMG_TYPE_DETECT, 0)) == NULL) {
tsk_error_print(stderr);
exit(1);
}
/* Make a version that can be more easily printed */
for (i = 0; i < sig_size; i++) {
sig_print |= (sig[i] << ((sig_size - 1 - i) * 8));
}
printf("Block size: %d Offset: %d Signature: %X\n", bs, sig_offset,
sig_print);
/* Loop through by blocks - we will read in block sized chunks
* so that we can be used on raw devices
*/
cur_offset = (sig_offset / 512) * 512;
rel_offset = sig_offset % 512;
prev_hit = -1;
for (i = 0;; i++) {
ssize_t retval;
/* Read the signature area */
retval = tsk_img_read(img_info, cur_offset,
(char *)block, read_size);
if (retval == 0) {
break;
}
else if (retval == -1) {
fprintf(stderr, "error reading bytes %" PRIdOFF "\n", i);
exit(1);
}
/* Check the sig */
if ((block[rel_offset] == sig[0]) &&
((sig_size < 2) || (block[rel_offset + 1] == sig[1])) &&
((sig_size < 3) || (block[rel_offset + 2] == sig[2])) &&
((sig_size < 4) || (block[rel_offset + 3] == sig[3]))) {
if (prev_hit == -1)
printf("Block: %" PRIdOFF " (-)\n", i);
else
printf("Block: %" PRIdOFF " (+%" PRIdOFF ")\n", i,
(i - prev_hit));
prev_hit = i;
}
cur_offset += bs;
}
tsk_img_close(img_info);
exit(0);
}
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