2 * loop-AES compatible volume handling
4 * Copyright (C) 2011, Red Hat, Inc. All rights reserved.
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * version 2 as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25 #include "crypto_backend.h"
28 static const char *get_hash(unsigned int key_size)
33 case 16: hash = "sha256"; break;
34 case 24: hash = "sha384"; break;
35 case 32: hash = "sha512"; break;
42 static unsigned char get_tweak(unsigned int keys_count)
52 static int hash_key(const char *src, size_t src_len,
53 char *dst, size_t dst_len,
54 const char *hash_name)
56 struct crypt_hash *hd = NULL;
58 if (crypt_hash_init(&hd, hash_name))
60 crypt_hash_write(hd, src, src_len);
61 crypt_hash_final(hd, dst, dst_len);
62 crypt_hash_destroy(hd);
66 static int hash_keys(struct volume_key **vk,
67 const char **input_keys,
68 unsigned int keys_count,
69 unsigned int key_len_output)
71 const char *hash_name;
73 int r, i, key_len_input;
75 hash_name = get_hash(key_len_output);
76 tweak = get_tweak(keys_count);
77 key_len_input = strlen(input_keys[0]);
79 if (!keys_count || !key_len_output || !hash_name || !key_len_input)
82 *vk = crypt_alloc_volume_key(key_len_output * keys_count, NULL);
86 for (i = 0; i < keys_count; i++) {
87 key_ptr = &(*vk)->key[i * key_len_output];
88 r = hash_key(input_keys[i], key_len_input, key_ptr,
89 key_len_output, hash_name);
97 crypt_free_volume_key(*vk);
103 static int keyfile_is_gpg(char *buffer, unsigned int buffer_len)
106 int index = buffer_len < 100 ? buffer_len - 1 : 100;
107 char eos = buffer[index];
109 buffer[index] = '\0';
110 if (strstr(buffer, "BEGIN PGP MESSAGE"))
116 int LOOPAES_parse_keyfile(struct crypt_device *cd,
117 struct volume_key **vk,
118 unsigned int *keys_count,
120 unsigned int buffer_len)
123 const char *keys[LOOPAES_KEYS_MAX];
124 int i, key_index, key_len, offset;
126 log_dbg("Parsing loop-AES keyfile of size %d.", buffer_len);
128 if (buffer_len < LOOPAES_KEYFILE_MINSIZE) {
129 log_err(cd, _("Incompatible loop-AES keyfile detected.\n"));
133 if (keyfile_is_gpg(buffer, buffer_len)) {
134 log_err(cd, "Detected not yet supported GPG encrypted keyfile.\n");
135 log_std(cd, "Please use gpg --decrypt <KEYFILE> | cryptsetup --keyfile=- ...\n");
139 /* Remove EOL in buffer */
140 for (i = 0; i < buffer_len; i++)
141 if (buffer[i] == '\n' || buffer[i] == '\r')
146 while (offset < buffer_len && key_index < LOOPAES_KEYS_MAX) {
147 keys[key_index++] = &buffer[offset];
148 while (offset < buffer_len && buffer[offset])
150 while (offset < buffer_len && !buffer[offset])
154 /* All keys must be the same length */
155 key_len = key_index ? strlen(keys[0]) : 0;
156 for (i = 0; i < key_index; i++)
157 if (key_len != strlen(keys[i])) {
158 log_dbg("Unexpected length %d of key #%d (should be %d).",
159 strlen(keys[i]), i, key_len);
164 log_dbg("Keyfile: %d keys of length %d.", key_index, key_len);
165 if (offset != buffer_len || key_len == 0 ||
166 (key_index != 1 && key_index !=64 && key_index != 65)) {
167 log_err(cd, _("Incompatible loop-AES keyfile detected.\n"));
171 *keys_count = key_index;
172 return hash_keys(vk, keys, key_index, crypt_get_volume_key_size(cd));
175 int LOOPAES_activate(struct crypt_device *cd,
177 const char *base_cipher,
178 unsigned int keys_count,
179 struct volume_key *vk,
182 uint64_t size, offset;
188 offset = crypt_get_data_offset(cd);
189 device = crypt_get_device_name(cd);
190 read_only = flags & CRYPT_ACTIVATE_READONLY;
192 r = device_check_and_adjust(cd, device, 1, &size, &offset, &read_only);
196 if (keys_count == 1) {
197 if (asprintf(&cipher, "%s-%s", base_cipher, "cbc-plain") < 0)
200 if (!(dm_flags() & DM_LMK_SUPPORTED)) {
201 log_err(cd, _("Kernel doesn't support loop-AES compatible mapping.\n"));
204 if (asprintf(&cipher, "%s:%d-%s", base_cipher, 64, "cbc-lmk") < 0)
208 log_dbg("Trying to activate loop-AES device %s using cipher %s.", name, cipher);
209 r = dm_create_device(name, device,
210 cipher, CRYPT_LOOPAES,
212 size, 0, offset, vk->keylength, vk->key,