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#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/dm-ioctl.h>
#include <sys/mount.h>
#include "../fs_mgr/include/fs_mgr.h"
#include "cryptfs.h"
#include "cutils/properties.h"
#ifndef PROPERTY_VALUE_MAX
#define PROPERTY_VALUE_MAX 255
#endif
#ifndef FSTAB_PREFIX
#define FSTAB_PREFIX "/fstab."
#endif
#ifndef KEY_IN_FOOTER
#define KEY_IN_FOOTER "footer"
#endif
struct fstab *fstab;
static unsigned int get_blkdev_size(int fd)
{
unsigned int nr_sec;
if ( (ioctl(fd, BLKGETSIZE, &nr_sec)) == -1) {
nr_sec = 0;
}
return nr_sec;
}
int get_crypt_ftr_info(char **metadata_fname, off64_t *off)
{
static int cached_data = 0;
static off64_t cached_off = 0;
static char cached_metadata_fname[PROPERTY_VALUE_MAX] = "";
int fd;
char key_loc[PROPERTY_VALUE_MAX];
char real_blkdev[PROPERTY_VALUE_MAX];
unsigned int nr_sec;
int rc = -1;
fs_mgr_get_crypt_info(fstab, key_loc, real_blkdev, sizeof(key_loc));
if (!strcmp(key_loc, KEY_IN_FOOTER)) {
if ( (fd = open(real_blkdev, O_RDWR)) < 0) {
printf("Cannot open real block device %s\n", real_blkdev);
return -1;
}
if ((nr_sec = get_blkdev_size(fd))) {
/* If it's an encrypted Android partition, the last 16 Kbytes contain the
* encryption info footer and key, and plenty of bytes to spare for future
* growth.
*/
strlcpy(cached_metadata_fname, real_blkdev, sizeof(cached_metadata_fname));
cached_off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET;
cached_data = 1;
} else {
printf("Cannot get size of block device %s\n", real_blkdev);
}
close(fd);
} else {
strlcpy(cached_metadata_fname, key_loc, sizeof(cached_metadata_fname));
cached_off = 0;
cached_data = 1;
}
if (cached_data) {
if (metadata_fname) {
*metadata_fname = cached_metadata_fname;
}
if (off) {
*off = cached_off;
}
rc = 0;
}
return rc;
}
int get_crypt_ftr_and_key(struct crypt_mnt_ftr *crypt_ftr)
{
int fd;
unsigned int nr_sec, cnt;
off64_t starting_off;
int rc = -1;
char *fname = NULL;
struct stat statbuf;
if (get_crypt_ftr_info(&fname, &starting_off)) {
printf("Unable to get crypt_ftr_info\n");
return -1;
}
if (fname[0] != '/') {
printf("Unexpected value for crypto key location '%s'\n", fname);
//return -1;
}
if ( (fd = open(fname, O_RDWR)) < 0) {
printf("Cannot open footer file %s for get\n", fname);
return -1;
}
/* Make sure it's 16 Kbytes in length */
fstat(fd, &statbuf);
if (S_ISREG(statbuf.st_mode) && (statbuf.st_size != 0x4000)) {
printf("footer file %s is not the expected size!\n", fname);
close(fd);
return -1;
}
/* Seek to the start of the crypt footer */
if (lseek64(fd, starting_off, SEEK_SET) == -1) {
printf("Cannot seek to real block device footer\n");
close(fd);
return -1;
}
if ( (cnt = read(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr))) != sizeof(struct crypt_mnt_ftr)) {
printf("Cannot read real block device footer\n");
close(fd);
return -1;
}
close(fd);
return 0;
}
int main(void)
{
char key_loc[PROPERTY_VALUE_MAX];
char blk_dev[PROPERTY_VALUE_MAX];
char fstab_filename[PROPERTY_VALUE_MAX + sizeof(FSTAB_PREFIX)];
struct stat st;
struct crypt_mnt_ftr crypt_ftr;
int fdout;
printf("This tool comes with no warranties whatsoever.\n");
printf("http://teamw.in\n\n");
strcpy(fstab_filename, FSTAB_PREFIX);
property_get("ro.hardware", fstab_filename + sizeof(FSTAB_PREFIX) - 1, "");
if (stat(fstab_filename, &st) != 0) {
printf("Cannot locate fstab file '%s'\n", fstab_filename);
return -1;
}
fstab = fs_mgr_read_fstab(fstab_filename);
if (!fstab) {
printf("failed to open %s\n", fstab_filename);
return -1;
}
fs_mgr_get_crypt_info(fstab, key_loc, blk_dev, sizeof(blk_dev));
if (get_crypt_ftr_and_key(&crypt_ftr)) {
printf("Error getting crypt footer and key\n");
return -1;
}
if ( (fdout = open("/footerfile", O_WRONLY | O_CREAT, 0644)) < 0) {
printf("Cannot open output file /footerfile\n");
return -1;
}
if (write(fdout, (void*) &crypt_ftr, sizeof(struct crypt_mnt_ftr)) != sizeof(struct crypt_mnt_ftr)) {
printf("Failed to write footer.\n");
}
close(fdout);
if (!strcmp(key_loc, KEY_IN_FOOTER)) {
unsigned int nr_sec, cnt;
off64_t off = 0;
char buffer[CRYPT_FOOTER_OFFSET];
int fd;
printf("\n\nDumping footer from '%s'...\n", blk_dev);
if ( (fd = open(blk_dev, O_RDONLY)) < 0) {
printf("Cannot open real block device %s\n", blk_dev);
return -1;
}
if ((nr_sec = get_blkdev_size(fd))) {
off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET;
} else {
printf("Cannot get size of block device %s\n", blk_dev);
close(fd);
return -1;
}
printf("Size is %llu, offset is %llu\n", ((off64_t)nr_sec * 512), off);
if (lseek64(fd, off, SEEK_SET) == -1) {
printf("Cannot seek to real block device footer\n");
close(fd);
return -1;
}
if ( (cnt = read(fd, buffer, sizeof(buffer))) != sizeof(buffer)) {
printf("Cannot read real block device footer\n");
close(fd);
return -1;
}
close(fd);
if ( (fdout = open("/footerdump", O_WRONLY | O_CREAT, 0644)) < 0) {
printf("Cannot open output file /footerdump\n");
return -1;
}
if (write(fdout, buffer, sizeof(buffer)) != sizeof(buffer)) {
printf("Failed to write footer.\n");
}
close(fdout);
}
return 0;
}
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