diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/luks1/keyencryption.c | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/lib/luks1/keyencryption.c b/lib/luks1/keyencryption.c new file mode 100644 index 0000000..c1c8201 --- /dev/null +++ b/lib/luks1/keyencryption.c @@ -0,0 +1,268 @@ +/* + * LUKS - Linux Unified Key Setup + * + * Copyright (C) 2004-2006 Clemens Fruhwirth <clemens@endorphin.org> + * Copyright (C) 2009-2023 Red Hat, Inc. All rights reserved. + * Copyright (C) 2012-2023 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 <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, false); + + 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, false); + + 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; +} |