/*
* LUKS - Linux Unified Key Setup
*
* Copyright (C) 2004-2006 Clemens Fruhwirth <clemens@endorphin.org>
* Copyright (C) 2009-2020 Red Hat, Inc. All rights reserved.
* Copyright (C) 2012-2020 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 <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include "luks.h"
#include "af.h"
#include "internal.h"
static void _error_hint(struct crypt_device *ctx, const char *device,
const char *cipher, const char *mode, size_t keyLength)
{
char *c, cipher_spec[MAX_CIPHER_LEN * 3];
if (snprintf(cipher_spec, sizeof(cipher_spec), "%s-%s", cipher, mode) < 0)
return;
log_err(ctx, _("Failed to setup dm-crypt key mapping for device %s.\n"
"Check that kernel supports %s cipher (check syslog for more info)."),
device, cipher_spec);
if (!strncmp(mode, "xts", 3) && (keyLength != 256 && keyLength != 512))
log_err(ctx, _("Key size in XTS mode must be 256 or 512 bits."));
else if (!(c = strchr(mode, '-')) || strlen(c) < 4)
log_err(ctx, _("Cipher specification should be in [cipher]-[mode]-[iv] format."));
}
static int LUKS_endec_template(char *src, size_t srcLength,
const char *cipher, const char *cipher_mode,
struct volume_key *vk,
unsigned int sector,
ssize_t (*func)(int, size_t, size_t, void *, size_t),
int mode,
struct crypt_device *ctx)
{
char name[PATH_MAX], path[PATH_MAX];
char cipher_spec[MAX_CIPHER_LEN * 3];
struct crypt_dm_active_device dmd = {
.flags = CRYPT_ACTIVATE_PRIVATE,
};
int r, devfd = -1, remove_dev = 0;
size_t bsize, keyslot_alignment, alignment;
log_dbg(ctx, "Using dmcrypt to access keyslot area.");
bsize = device_block_size(ctx, crypt_metadata_device(ctx));
alignment = device_alignment(crypt_metadata_device(ctx));
if (!bsize || !alignment)
return -EINVAL;
if (bsize > LUKS_ALIGN_KEYSLOTS)
keyslot_alignment = LUKS_ALIGN_KEYSLOTS;
else
keyslot_alignment = bsize;
dmd.size = size_round_up(srcLength, keyslot_alignment) / SECTOR_SIZE;
if (mode == O_RDONLY)
dmd.flags |= CRYPT_ACTIVATE_READONLY;
if (snprintf(name, sizeof(name), "temporary-cryptsetup-%d", getpid()) < 0)
return -ENOMEM;
if (snprintf(path, sizeof(path), "%s/%s", dm_get_dir(), name) < 0)
return -ENOMEM;
if (snprintf(cipher_spec, sizeof(cipher_spec), "%s-%s", cipher, cipher_mode) < 0)
return -ENOMEM;
r = device_block_adjust(ctx, crypt_metadata_device(ctx), DEV_OK,
sector, &dmd.size, &dmd.flags);
if (r < 0) {
log_err(ctx, _("Device %s does not exist or access denied."),
device_path(crypt_metadata_device(ctx)));
return -EIO;
}
if (mode != O_RDONLY && dmd.flags & CRYPT_ACTIVATE_READONLY) {
log_err(ctx, _("Cannot write to device %s, permission denied."),
device_path(crypt_metadata_device(ctx)));
return -EACCES;
}
r = dm_crypt_target_set(&dmd.segment, 0, dmd.size,
crypt_metadata_device(ctx), vk, cipher_spec, 0, sector,
NULL, 0, SECTOR_SIZE);
if (r)
goto out;
r = dm_create_device(ctx, name, "TEMP", &dmd);
if (r < 0) {
if (r != -EACCES && r != -ENOTSUP)
_error_hint(ctx, device_path(crypt_metadata_device(ctx)),
cipher, cipher_mode, vk->keylength * 8);
r = -EIO;
goto out;
}
remove_dev = 1;
devfd = open(path, mode | O_DIRECT | O_SYNC);
if (devfd == -1) {
log_err(ctx, _("Failed to open temporary keystore device."));
r = -EIO;
goto out;
}
r = func(devfd, bsize, alignment, src, srcLength);
if (r < 0) {
log_err(ctx, _("Failed to access temporary keystore device."));
r = -EIO;
} else
r = 0;
out:
dm_targets_free(ctx, &dmd);
if (devfd != -1)
close(devfd);
if (remove_dev)
dm_remove_device(ctx, name, CRYPT_DEACTIVATE_FORCE);
return r;
}
int LUKS_encrypt_to_storage(char *src, size_t srcLength,
const char *cipher,
const char *cipher_mode,
struct volume_key *vk,
unsigned int sector,
struct crypt_device *ctx)
{
struct device *device = crypt_metadata_device(ctx);
struct crypt_storage *s;
int devfd, r = 0;
/* Only whole sector writes supported */
if (MISALIGNED_512(srcLength))
return -EINVAL;
/* Encrypt buffer */
r = crypt_storage_init(&s, SECTOR_SIZE, cipher, cipher_mode, vk->key, vk->keylength);
if (r)
log_dbg(ctx, "Userspace crypto wrapper cannot use %s-%s (%d).",
cipher, cipher_mode, r);
/* Fallback to old temporary dmcrypt device */
if (r == -ENOTSUP || r == -ENOENT)
return LUKS_endec_template(src, srcLength, cipher, cipher_mode,
vk, sector, write_blockwise, O_RDWR, ctx);
if (r) {
_error_hint(ctx, device_path(device), cipher, cipher_mode,
vk->keylength * 8);
return r;
}
log_dbg(ctx, "Using userspace crypto wrapper to access keyslot area.");
r = crypt_storage_encrypt(s, 0, srcLength, src);
crypt_storage_destroy(s);
if (r)
return r;
r = -EIO;
/* Write buffer to device */
if (device_is_locked(device))
devfd = device_open_locked(ctx, device, O_RDWR);
else
devfd = device_open(ctx, device, O_RDWR);
if (devfd < 0)
goto out;
if (write_lseek_blockwise(devfd, device_block_size(ctx, device),
device_alignment(device), src, srcLength,
sector * SECTOR_SIZE) < 0)
goto out;
r = 0;
out:
device_sync(ctx, device);
if (r)
log_err(ctx, _("IO error while encrypting keyslot."));
return r;
}
int LUKS_decrypt_from_storage(char *dst, size_t dstLength,
const char *cipher,
const char *cipher_mode,
struct volume_key *vk,
unsigned int sector,
struct crypt_device *ctx)
{
struct device *device = crypt_metadata_device(ctx);
struct crypt_storage *s;
struct stat st;
int devfd, r = 0;
/* Only whole sector reads supported */
if (MISALIGNED_512(dstLength))
return -EINVAL;
r = crypt_storage_init(&s, SECTOR_SIZE, cipher, cipher_mode, vk->key, vk->keylength);
if (r)
log_dbg(ctx, "Userspace crypto wrapper cannot use %s-%s (%d).",
cipher, cipher_mode, r);
/* Fallback to old temporary dmcrypt device */
if (r == -ENOTSUP || r == -ENOENT)
return LUKS_endec_template(dst, dstLength, cipher, cipher_mode,
vk, sector, read_blockwise, O_RDONLY, ctx);
if (r) {
_error_hint(ctx, device_path(device), cipher, cipher_mode,
vk->keylength * 8);
return r;
}
log_dbg(ctx, "Using userspace crypto wrapper to access keyslot area.");
/* Read buffer from device */
if (device_is_locked(device))
devfd = device_open_locked(ctx, device, O_RDONLY);
else
devfd = device_open(ctx, device, O_RDONLY);
if (devfd < 0) {
log_err(ctx, _("Cannot open device %s."), device_path(device));
crypt_storage_destroy(s);
return -EIO;
}
if (read_lseek_blockwise(devfd, device_block_size(ctx, device),
device_alignment(device), dst, dstLength,
sector * SECTOR_SIZE) < 0) {
if (!fstat(devfd, &st) && (st.st_size < (off_t)dstLength))
log_err(ctx, _("Device %s is too small."), device_path(device));
else
log_err(ctx, _("IO error while decrypting keyslot."));
crypt_storage_destroy(s);
return -EIO;
}
/* Decrypt buffer */
r = crypt_storage_decrypt(s, 0, dstLength, dst);
crypt_storage_destroy(s);
return r;
}