/*
* utils_wipe - wipe a device
*
* Copyright (C) 2004-2007 Clemens Fruhwirth <clemens@endorphin.org>
* Copyright (C) 2009-2020 Red Hat, Inc. All rights reserved.
* Copyright (C) 2009-2020 Milan Broz
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <stdlib.h>
#include <errno.h>
#include "internal.h"
/*
* Wipe using Peter Gutmann method described in
* http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html
* Note: used only for rotational device (and even there it is not needed today...)
*/
static void wipeSpecial(char *buffer, size_t buffer_size, unsigned int turn)
{
unsigned int i;
unsigned char write_modes[][3] = {
{"\x55\x55\x55"}, {"\xaa\xaa\xaa"}, {"\x92\x49\x24"},
{"\x49\x24\x92"}, {"\x24\x92\x49"}, {"\x00\x00\x00"},
{"\x11\x11\x11"}, {"\x22\x22\x22"}, {"\x33\x33\x33"},
{"\x44\x44\x44"}, {"\x55\x55\x55"}, {"\x66\x66\x66"},
{"\x77\x77\x77"}, {"\x88\x88\x88"}, {"\x99\x99\x99"},
{"\xaa\xaa\xaa"}, {"\xbb\xbb\xbb"}, {"\xcc\xcc\xcc"},
{"\xdd\xdd\xdd"}, {"\xee\xee\xee"}, {"\xff\xff\xff"},
{"\x92\x49\x24"}, {"\x49\x24\x92"}, {"\x24\x92\x49"},
{"\x6d\xb6\xdb"}, {"\xb6\xdb\x6d"}, {"\xdb\x6d\xb6"}
};
for (i = 0; i < buffer_size / 3; ++i) {
memcpy(buffer, write_modes[turn], 3);
buffer += 3;
}
}
static int crypt_wipe_special(struct crypt_device *cd, int fd, size_t bsize,
size_t alignment, char *buffer,
uint64_t offset, size_t size)
{
int r = 0;
unsigned int i;
ssize_t written;
for (i = 0; i < 39; ++i) {
if (i < 5) {
r = crypt_random_get(cd, buffer, size, CRYPT_RND_NORMAL);
} else if (i >= 5 && i < 32) {
wipeSpecial(buffer, size, i - 5);
r = 0;
} else if (i >= 32 && i < 38) {
r = crypt_random_get(cd, buffer, size, CRYPT_RND_NORMAL);
} else if (i >= 38 && i < 39) {
memset(buffer, 0xFF, size);
r = 0;
}
if (r < 0)
return -EIO;
written = write_lseek_blockwise(fd, bsize, alignment,
buffer, size, offset);
if (written < 0 || written != (ssize_t)size)
return -EIO;
}
/* Rewrite it finally with random */
if (crypt_random_get(cd, buffer, size, CRYPT_RND_NORMAL) < 0)
return -EIO;
written = write_lseek_blockwise(fd, bsize, alignment, buffer, size, offset);
if (written < 0 || written != (ssize_t)size)
return -EIO;
return 0;
}
static int wipe_block(struct crypt_device *cd, int devfd, crypt_wipe_pattern pattern,
char *sf, size_t device_block_size, size_t alignment,
size_t wipe_block_size, uint64_t offset, bool *need_block_init)
{
int r;
if (pattern == CRYPT_WIPE_SPECIAL)
return crypt_wipe_special(cd, devfd, device_block_size, alignment,
sf, offset, wipe_block_size);
if (*need_block_init) {
if (pattern == CRYPT_WIPE_ZERO) {
memset(sf, 0, wipe_block_size);
*need_block_init = false;
r = 0;
} else if (pattern == CRYPT_WIPE_RANDOM) {
r = crypt_random_get(cd, sf, wipe_block_size,
CRYPT_RND_NORMAL) ? -EIO : 0;
*need_block_init = true;
} else if (pattern == CRYPT_WIPE_ENCRYPTED_ZERO) {
// FIXME
r = crypt_random_get(cd, sf, wipe_block_size,
CRYPT_RND_NORMAL) ? -EIO : 0;
*need_block_init = true;
} else
r = -EINVAL;
if (r)
return r;
}
if (write_blockwise(devfd, device_block_size, alignment, sf,
wipe_block_size) == (ssize_t)wipe_block_size)
return 0;
return -EIO;
}
int crypt_wipe_device(struct crypt_device *cd,
struct device *device,
crypt_wipe_pattern pattern,
uint64_t offset,
uint64_t length,
size_t wipe_block_size,
int (*progress)(uint64_t size, uint64_t offset, void *usrptr),
void *usrptr)
{
int r, devfd;
size_t bsize, alignment;
char *sf = NULL;
uint64_t dev_size;
bool need_block_init = true;
/* Note: LUKS1 calls it with wipe_block not aligned to multiple of bsize */
bsize = device_block_size(cd, device);
alignment = device_alignment(device);
if (!bsize || !alignment || !wipe_block_size)
return -EINVAL;
/* FIXME: if wipe_block_size < bsize, then a wipe is highly ineffective */
/* Everything must be aligned to SECTOR_SIZE */
if (MISALIGNED_512(offset) || MISALIGNED_512(length) || MISALIGNED_512(wipe_block_size))
return -EINVAL;
if (device_is_locked(device))
devfd = device_open_locked(cd, device, O_RDWR);
else
devfd = device_open(cd, device, O_RDWR);
if (devfd < 0)
return errno ? -errno : -EINVAL;
if (length)
dev_size = offset + length;
else {
r = device_size(device, &dev_size);
if (r)
goto out;
if (dev_size <= offset) {
r = -EINVAL;
goto out;
}
}
r = posix_memalign((void **)&sf, alignment, wipe_block_size);
if (r)
goto out;
if (lseek64(devfd, offset, SEEK_SET) < 0) {
log_err(cd, _("Cannot seek to device offset."));
r = -EINVAL;
goto out;
}
if (progress && progress(dev_size, offset, usrptr)) {
r = -EINVAL; /* No change yet, treat this as a parameter error */
goto out;
}
if (pattern == CRYPT_WIPE_SPECIAL && !device_is_rotational(device)) {
log_dbg(cd, "Non-rotational device, using random data wipe mode.");
pattern = CRYPT_WIPE_RANDOM;
}
while (offset < dev_size) {
if ((offset + wipe_block_size) > dev_size)
wipe_block_size = dev_size - offset;
//log_dbg("Wipe %012" PRIu64 "-%012" PRIu64 " bytes", offset, offset + wipe_block_size);
r = wipe_block(cd, devfd, pattern, sf, bsize, alignment,
wipe_block_size, offset, &need_block_init);
if (r) {
log_err(cd,_("Device wipe error, offset %" PRIu64 "."), offset);
break;
}
offset += wipe_block_size;
if (progress && progress(dev_size, offset, usrptr)) {
r = -EINTR;
break;
}
}
device_sync(cd, device);
out:
free(sf);
return r;
}
int crypt_wipe(struct crypt_device *cd,
const char *dev_path,
crypt_wipe_pattern pattern,
uint64_t offset,
uint64_t length,
size_t wipe_block_size,
uint32_t flags,
int (*progress)(uint64_t size, uint64_t offset, void *usrptr),
void *usrptr)
{
struct device *device;
int r;
if (!cd)
return -EINVAL;
if (!dev_path)
device = crypt_data_device(cd);
else {
r = device_alloc_no_check(&device, dev_path);
if (r < 0)
return r;
if (flags & CRYPT_WIPE_NO_DIRECT_IO)
device_disable_direct_io(device);
}
if (!wipe_block_size)
wipe_block_size = 1024*1024;
log_dbg(cd, "Wipe [%u] device %s, offset %" PRIu64 ", length %" PRIu64 ", block %zu.",
(unsigned)pattern, device_path(device), offset, length, wipe_block_size);
r = crypt_wipe_device(cd, device, pattern, offset, length,
wipe_block_size, progress, usrptr);
if (dev_path)
device_free(cd, device);
return r;
}