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/*
* utils_wipe - wipe a device
*
* Copyright (C) 2004-2007, Clemens Fruhwirth <clemens@endorphin.org>
* Copyright (C) 2011-2012, Red Hat, Inc. All rights reserved.
* Copyright (C) 2009-2012, 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 <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include "libcryptsetup.h"
#include "internal.h"
#define MAXIMUM_WIPE_BYTES 1024 * 1024 * 32 /* 32 MiB */
static ssize_t _crypt_wipe_zero(int fd, int bsize, char *buffer,
uint64_t offset, uint64_t size)
{
memset(buffer, 0, size);
return write_lseek_blockwise(fd, bsize, buffer, size, offset);
}
static ssize_t _crypt_wipe_random(int fd, int bsize, char *buffer,
uint64_t offset, uint64_t size)
{
if (crypt_random_get(NULL, buffer, size, CRYPT_RND_NORMAL) < 0)
return -EINVAL;
return write_lseek_blockwise(fd, bsize, buffer, size, offset);
}
/*
* Wipe using Peter Gutmann method described in
* http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html
*/
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 ssize_t _crypt_wipe_disk(int fd, int bsize, char *buffer,
uint64_t offset, uint64_t size)
{
int r;
unsigned int i;
ssize_t written;
for(i = 0; i < 39; ++i) {
if (i < 5) {
r = crypt_random_get(NULL, 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(NULL, buffer, size, CRYPT_RND_NORMAL);
} else if(i >= 38 && i < 39) {
memset(buffer, 0xFF, size);
r = 0;
}
if (r < 0)
return r;
written = write_lseek_blockwise(fd, bsize, buffer, size, offset);
if (written < 0 || written != (ssize_t)size)
return written;
}
/* Rewrite it finally with random */
return _crypt_wipe_random(fd, bsize, buffer, offset, size);
}
static ssize_t _crypt_wipe_ssd(int fd, int bsize, char *buffer,
uint64_t offset, uint64_t size)
{
// FIXME: for now just rewrite it by random
return _crypt_wipe_random(fd, bsize, buffer, offset, size);
}
int crypt_wipe(struct device *device,
uint64_t offset,
uint64_t size,
crypt_wipe_type type,
int exclusive)
{
struct stat st;
char *buffer;
int devfd, flags, bsize;
ssize_t written;
if (!size || size % SECTOR_SIZE || (size > MAXIMUM_WIPE_BYTES)) {
log_dbg("Unsuported wipe size for device %s: %ld.",
device_path(device), (unsigned long)size);
return -EINVAL;
}
if (stat(device_path(device), &st) < 0) {
log_dbg("Device %s not found.", device_path(device));
return -EINVAL;
}
if (type == CRYPT_WIPE_DISK && S_ISBLK(st.st_mode)) {
if (!crypt_dev_is_rotational(major(st.st_rdev),
minor(st.st_rdev))) {
type = CRYPT_WIPE_SSD;
log_dbg("Non-rotational device, using SSD wipe mode.");
} else
log_dbg("Rotational device, using normal wipe mode.");
}
bsize = device_block_size(device);
if (bsize <= 0)
return -EINVAL;
buffer = malloc(size);
if (!buffer)
return -ENOMEM;
flags = O_RDWR;
/* use O_EXCL only for block devices */
if (exclusive && S_ISBLK(st.st_mode))
flags |= O_EXCL;
/* coverity[toctou] */
devfd = device_open(device, flags);
if (devfd == -1) {
free(buffer);
return errno ? -errno : -EINVAL;
}
// FIXME: use fixed block size and loop here
switch (type) {
case CRYPT_WIPE_ZERO:
written = _crypt_wipe_zero(devfd, bsize, buffer, offset, size);
break;
case CRYPT_WIPE_DISK:
written = _crypt_wipe_disk(devfd, bsize, buffer, offset, size);
break;
case CRYPT_WIPE_SSD:
written = _crypt_wipe_ssd(devfd, bsize, buffer, offset, size);
break;
case CRYPT_WIPE_RANDOM:
written = _crypt_wipe_random(devfd, bsize, buffer, offset, size);
break;
default:
log_dbg("Unsuported wipe type requested: (%d)", type);
written = -1;
}
close(devfd);
free(buffer);
if (written != (ssize_t)size || written < 0)
return -EIO;
return 0;
}
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