diff options
Diffstat (limited to 'crypto/crypttools/getfooter.c')
| -rw-r--r-- | crypto/crypttools/getfooter.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/crypto/crypttools/getfooter.c b/crypto/crypttools/getfooter.c new file mode 100644 index 000000000..aa7f88e84 --- /dev/null +++ b/crypto/crypttools/getfooter.c @@ -0,0 +1,219 @@ +#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; +} |