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Diffstat (limited to '')
| -rw-r--r-- | lib/utils_wipe.c | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/lib/utils_wipe.c b/lib/utils_wipe.c new file mode 100644 index 0000000..1df46c1 --- /dev/null +++ b/lib/utils_wipe.c @@ -0,0 +1,311 @@ +/* + * utils_wipe - wipe a device + * + * Copyright (C) 2004-2007 Clemens Fruhwirth <clemens@endorphin.org> + * Copyright (C) 2009-2023 Red Hat, Inc. All rights reserved. + * Copyright (C) 2009-2023 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 <sys/ioctl.h> +#include <sys/stat.h> +#include <linux/fs.h> +#include "internal.h" + +/* block device zeroout ioctls, introduced in Linux kernel 3.7 */ +#ifndef BLKZEROOUT +#define BLKZEROOUT _IO(0x12,127) +#endif + +static int wipe_zeroout(struct crypt_device *cd, int devfd, + uint64_t offset, uint64_t length) +{ + static bool zeroout_available = true; + uint64_t range[2] = { offset, length }; + int r; + + if (!zeroout_available) + return -ENOTSUP; + + r = ioctl(devfd, BLKZEROOUT, &range); + if (r < 0) { + log_dbg(cd, "BLKZEROOUT ioctl not available (error %i), disabling.", r); + zeroout_available = false; + return -ENOTSUP; + } + + return 0; +} + +/* + * Wipe using Peter Gutmann method described in + * https://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, + bool blockdev) +{ + 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 || + pattern == CRYPT_WIPE_ENCRYPTED_ZERO) { + 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 (blockdev && pattern == CRYPT_WIPE_ZERO && + !wipe_zeroout(cd, devfd, offset, wipe_block_size)) { + /* zeroout ioctl does not move offset */ + if (lseek(devfd, offset + wipe_block_size, SEEK_SET) < 0) { + log_err(cd, _("Cannot seek to device offset.")); + return -EINVAL; + } + return 0; + } + + 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; + struct stat st; + 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; + + /* 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 (fstat(devfd, &st) < 0) { + r = -EINVAL; + goto out; + } + + 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 (lseek(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; + + r = wipe_block(cd, devfd, pattern, sf, bsize, alignment, + wipe_block_size, offset, &need_block_init, S_ISBLK(st.st_mode)); + 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; + + r = init_crypto(cd); + if (r < 0) + return r; + + 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 (!device) + return -EINVAL; + + 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; +} |