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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 08:06:26 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 08:06:26 +0000 |
commit | 1660d4b7a65d9ad2ce0deaa19d35579ca4084ac5 (patch) | |
tree | 6cf8220b628ebd2ccfc1375dd6516c6996e9abcc /lib/loopaes/loopaes.c | |
parent | Initial commit. (diff) | |
download | cryptsetup-1660d4b7a65d9ad2ce0deaa19d35579ca4084ac5.tar.xz cryptsetup-1660d4b7a65d9ad2ce0deaa19d35579ca4084ac5.zip |
Adding upstream version 2:2.6.1.upstream/2%2.6.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | lib/loopaes/loopaes.c | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/lib/loopaes/loopaes.c b/lib/loopaes/loopaes.c new file mode 100644 index 0000000..224d3d0 --- /dev/null +++ b/lib/loopaes/loopaes.c @@ -0,0 +1,253 @@ +/* + * loop-AES compatible volume handling + * + * Copyright (C) 2011-2023 Red Hat, Inc. All rights reserved. + * Copyright (C) 2011-2023 Milan Broz + * + * This file is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This file 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this file; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "libcryptsetup.h" +#include "loopaes.h" +#include "internal.h" + +static const char *get_hash(unsigned int key_size) +{ + const char *hash; + + switch (key_size) { + case 16: hash = "sha256"; break; + case 24: hash = "sha384"; break; + case 32: hash = "sha512"; break; + default: hash = NULL; + } + + return hash; +} + +static unsigned char get_tweak(unsigned int keys_count) +{ + switch (keys_count) { + case 64: return 0x55; + case 65: return 0xF4; + default: break; + } + return 0x00; +} + +static int hash_key(const char *src, size_t src_len, + char *dst, size_t dst_len, + const char *hash_name) +{ + struct crypt_hash *hd = NULL; + int r; + + if (crypt_hash_init(&hd, hash_name)) + return -EINVAL; + + r = crypt_hash_write(hd, src, src_len); + if (!r) + r = crypt_hash_final(hd, dst, dst_len); + + crypt_hash_destroy(hd); + return r; +} + +static int hash_keys(struct crypt_device *cd, + struct volume_key **vk, + const char *hash_override, + const char **input_keys, + unsigned int keys_count, + unsigned int key_len_output, + unsigned int key_len_input) +{ + const char *hash_name; + char tweak, *key_ptr; + unsigned int i; + int r = 0; + + hash_name = hash_override ?: get_hash(key_len_output); + tweak = get_tweak(keys_count); + + if (!keys_count || !key_len_output || !hash_name || !key_len_input) { + log_err(cd, _("Key processing error (using hash %s)."), + hash_name ?: "[none]"); + return -EINVAL; + } + + *vk = crypt_alloc_volume_key((size_t)key_len_output * keys_count, NULL); + if (!*vk) + return -ENOMEM; + + for (i = 0; i < keys_count; i++) { + key_ptr = &(*vk)->key[i * key_len_output]; + r = hash_key(input_keys[i], key_len_input, key_ptr, + key_len_output, hash_name); + if (r < 0) + break; + + key_ptr[0] ^= tweak; + } + + if (r < 0 && *vk) { + crypt_free_volume_key(*vk); + *vk = NULL; + } + return r; +} + +static int keyfile_is_gpg(char *buffer, size_t buffer_len) +{ + int r = 0; + int index = buffer_len < 100 ? buffer_len - 1 : 100; + char eos = buffer[index]; + + buffer[index] = '\0'; + if (strstr(buffer, "BEGIN PGP MESSAGE")) + r = 1; + buffer[index] = eos; + return r; +} + +int LOOPAES_parse_keyfile(struct crypt_device *cd, + struct volume_key **vk, + const char *hash, + unsigned int *keys_count, + char *buffer, + size_t buffer_len) +{ + const char *keys[LOOPAES_KEYS_MAX]; + unsigned int key_lengths[LOOPAES_KEYS_MAX]; + unsigned int i, key_index, key_len, offset; + + log_dbg(cd, "Parsing loop-AES keyfile of size %zu.", buffer_len); + + if (!buffer_len) + return -EINVAL; + + if (keyfile_is_gpg(buffer, buffer_len)) { + log_err(cd, _("Detected not yet supported GPG encrypted keyfile.")); + log_std(cd, _("Please use gpg --decrypt <KEYFILE> | cryptsetup --keyfile=- ...\n")); + return -EINVAL; + } + + /* Remove EOL in buffer */ + for (i = 0; i < buffer_len; i++) + if (buffer[i] == '\n' || buffer[i] == '\r') + buffer[i] = '\0'; + + offset = 0; + key_index = 0; + key_lengths[0] = 0; + while (offset < buffer_len && key_index < LOOPAES_KEYS_MAX) { + keys[key_index] = &buffer[offset]; + key_lengths[key_index] = 0;; + while (offset < buffer_len && buffer[offset]) { + offset++; + key_lengths[key_index]++; + } + if (offset == buffer_len) { + log_dbg(cd, "Unterminated key #%d in keyfile.", key_index); + log_err(cd, _("Incompatible loop-AES keyfile detected.")); + return -EINVAL; + } + while (offset < buffer_len && !buffer[offset]) + offset++; + key_index++; + } + + /* All keys must be the same length */ + key_len = key_lengths[0]; + for (i = 0; i < key_index; i++) + if (!key_lengths[i] || (key_lengths[i] != key_len)) { + log_dbg(cd, "Unexpected length %d of key #%d (should be %d).", + key_lengths[i], i, key_len); + key_len = 0; + break; + } + + if (offset != buffer_len || key_len == 0 || + (key_index != 1 && key_index !=64 && key_index != 65)) { + log_err(cd, _("Incompatible loop-AES keyfile detected.")); + return -EINVAL; + } + + log_dbg(cd, "Keyfile: %d keys of length %d.", key_index, key_len); + + *keys_count = key_index; + return hash_keys(cd, vk, hash, keys, key_index, + crypt_get_volume_key_size(cd), key_len); +} + +int LOOPAES_activate(struct crypt_device *cd, + const char *name, + const char *base_cipher, + unsigned int keys_count, + struct volume_key *vk, + uint32_t flags) +{ + int r; + uint32_t req_flags, dmc_flags; + char *cipher = NULL; + struct crypt_dm_active_device dmd = { + .flags = flags, + }; + + r = device_block_adjust(cd, crypt_data_device(cd), DEV_EXCL, + crypt_get_data_offset(cd), &dmd.size, &dmd.flags); + if (r) + return r; + + if (keys_count == 1) { + req_flags = DM_PLAIN64_SUPPORTED; + r = asprintf(&cipher, "%s-%s", base_cipher, "cbc-plain64"); + } else { + req_flags = DM_LMK_SUPPORTED; + r = asprintf(&cipher, "%s:%d-%s", base_cipher, 64, "cbc-lmk"); + } + if (r < 0) + return -ENOMEM; + + r = dm_crypt_target_set(&dmd.segment, 0, dmd.size, crypt_data_device(cd), + vk, cipher, crypt_get_iv_offset(cd), + crypt_get_data_offset(cd), crypt_get_integrity(cd), + crypt_get_integrity_tag_size(cd), crypt_get_sector_size(cd)); + + if (r) { + free(cipher); + return r; + } + + log_dbg(cd, "Trying to activate loop-AES device %s using cipher %s.", + name, cipher); + + r = dm_create_device(cd, name, CRYPT_LOOPAES, &dmd); + + if (r < 0 && !dm_flags(cd, DM_CRYPT, &dmc_flags) && + (dmc_flags & req_flags) != req_flags) { + log_err(cd, _("Kernel does not support loop-AES compatible mapping.")); + r = -ENOTSUP; + } + + dm_targets_free(cd, &dmd); + free(cipher); + + return r; +} |