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7d969014 DB |
1 | /* |
2 | * QEMU Crypto block device encryption QCow/QCow2 AES-CBC format | |
3 | * | |
4 | * Copyright (c) 2015-2016 Red Hat, Inc. | |
5 | * | |
6 | * This library is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * This library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, see <http://www.gnu.org/licenses/>. | |
18 | * | |
19 | */ | |
20 | ||
21 | /* | |
22 | * Note that the block encryption implemented in this file is broken | |
23 | * by design. This exists only to allow data to be liberated from | |
24 | * existing qcow[2] images and should not be used in any new areas. | |
25 | */ | |
26 | ||
27 | #include "qemu/osdep.h" | |
da34e65c | 28 | #include "qapi/error.h" |
7d969014 DB |
29 | |
30 | #include "crypto/block-qcow.h" | |
31 | #include "crypto/secret.h" | |
32 | ||
33 | #define QCRYPTO_BLOCK_QCOW_SECTOR_SIZE 512 | |
34 | ||
35 | ||
36 | static bool | |
37 | qcrypto_block_qcow_has_format(const uint8_t *buf G_GNUC_UNUSED, | |
38 | size_t buf_size G_GNUC_UNUSED) | |
39 | { | |
40 | return false; | |
41 | } | |
42 | ||
43 | ||
44 | static int | |
45 | qcrypto_block_qcow_init(QCryptoBlock *block, | |
46 | const char *keysecret, | |
47 | Error **errp) | |
48 | { | |
49 | char *password; | |
50 | int ret; | |
51 | uint8_t keybuf[16]; | |
52 | int len; | |
53 | ||
54 | memset(keybuf, 0, 16); | |
55 | ||
56 | password = qcrypto_secret_lookup_as_utf8(keysecret, errp); | |
57 | if (!password) { | |
58 | return -1; | |
59 | } | |
60 | ||
61 | len = strlen(password); | |
62 | memcpy(keybuf, password, MIN(len, sizeof(keybuf))); | |
63 | g_free(password); | |
64 | ||
65 | block->niv = qcrypto_cipher_get_iv_len(QCRYPTO_CIPHER_ALG_AES_128, | |
66 | QCRYPTO_CIPHER_MODE_CBC); | |
67 | block->ivgen = qcrypto_ivgen_new(QCRYPTO_IVGEN_ALG_PLAIN64, | |
68 | 0, 0, NULL, 0, errp); | |
69 | if (!block->ivgen) { | |
70 | ret = -ENOTSUP; | |
71 | goto fail; | |
72 | } | |
73 | ||
74 | block->cipher = qcrypto_cipher_new(QCRYPTO_CIPHER_ALG_AES_128, | |
75 | QCRYPTO_CIPHER_MODE_CBC, | |
76 | keybuf, G_N_ELEMENTS(keybuf), | |
77 | errp); | |
78 | if (!block->cipher) { | |
79 | ret = -ENOTSUP; | |
80 | goto fail; | |
81 | } | |
82 | ||
850f49de | 83 | block->sector_size = QCRYPTO_BLOCK_QCOW_SECTOR_SIZE; |
7d969014 DB |
84 | block->payload_offset = 0; |
85 | ||
86 | return 0; | |
87 | ||
88 | fail: | |
89 | qcrypto_cipher_free(block->cipher); | |
90 | qcrypto_ivgen_free(block->ivgen); | |
91 | return ret; | |
92 | } | |
93 | ||
94 | ||
95 | static int | |
96 | qcrypto_block_qcow_open(QCryptoBlock *block, | |
97 | QCryptoBlockOpenOptions *options, | |
1cd9a787 | 98 | const char *optprefix, |
7d969014 DB |
99 | QCryptoBlockReadFunc readfunc G_GNUC_UNUSED, |
100 | void *opaque G_GNUC_UNUSED, | |
101 | unsigned int flags, | |
102 | Error **errp) | |
103 | { | |
104 | if (flags & QCRYPTO_BLOCK_OPEN_NO_IO) { | |
105 | return 0; | |
106 | } else { | |
107 | if (!options->u.qcow.key_secret) { | |
108 | error_setg(errp, | |
1cd9a787 DB |
109 | "Parameter '%skey-secret' is required for cipher", |
110 | optprefix ? optprefix : ""); | |
7d969014 DB |
111 | return -1; |
112 | } | |
113 | return qcrypto_block_qcow_init(block, | |
114 | options->u.qcow.key_secret, errp); | |
115 | } | |
116 | } | |
117 | ||
118 | ||
119 | static int | |
120 | qcrypto_block_qcow_create(QCryptoBlock *block, | |
121 | QCryptoBlockCreateOptions *options, | |
1cd9a787 | 122 | const char *optprefix, |
7d969014 DB |
123 | QCryptoBlockInitFunc initfunc G_GNUC_UNUSED, |
124 | QCryptoBlockWriteFunc writefunc G_GNUC_UNUSED, | |
125 | void *opaque G_GNUC_UNUSED, | |
126 | Error **errp) | |
127 | { | |
128 | if (!options->u.qcow.key_secret) { | |
1cd9a787 DB |
129 | error_setg(errp, "Parameter '%skey-secret' is required for cipher", |
130 | optprefix ? optprefix : ""); | |
7d969014 DB |
131 | return -1; |
132 | } | |
133 | /* QCow2 has no special header, since everything is hardwired */ | |
134 | return qcrypto_block_qcow_init(block, options->u.qcow.key_secret, errp); | |
135 | } | |
136 | ||
137 | ||
138 | static void | |
139 | qcrypto_block_qcow_cleanup(QCryptoBlock *block) | |
140 | { | |
141 | } | |
142 | ||
143 | ||
144 | static int | |
145 | qcrypto_block_qcow_decrypt(QCryptoBlock *block, | |
4609742a | 146 | uint64_t offset, |
7d969014 DB |
147 | uint8_t *buf, |
148 | size_t len, | |
149 | Error **errp) | |
150 | { | |
4609742a DB |
151 | assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE)); |
152 | assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE)); | |
7d969014 DB |
153 | return qcrypto_block_decrypt_helper(block->cipher, |
154 | block->niv, block->ivgen, | |
155 | QCRYPTO_BLOCK_QCOW_SECTOR_SIZE, | |
4609742a | 156 | offset, buf, len, errp); |
7d969014 DB |
157 | } |
158 | ||
159 | ||
160 | static int | |
161 | qcrypto_block_qcow_encrypt(QCryptoBlock *block, | |
4609742a | 162 | uint64_t offset, |
7d969014 DB |
163 | uint8_t *buf, |
164 | size_t len, | |
165 | Error **errp) | |
166 | { | |
4609742a DB |
167 | assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE)); |
168 | assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE)); | |
7d969014 DB |
169 | return qcrypto_block_encrypt_helper(block->cipher, |
170 | block->niv, block->ivgen, | |
171 | QCRYPTO_BLOCK_QCOW_SECTOR_SIZE, | |
4609742a | 172 | offset, buf, len, errp); |
7d969014 DB |
173 | } |
174 | ||
175 | ||
176 | const QCryptoBlockDriver qcrypto_block_driver_qcow = { | |
177 | .open = qcrypto_block_qcow_open, | |
178 | .create = qcrypto_block_qcow_create, | |
179 | .cleanup = qcrypto_block_qcow_cleanup, | |
180 | .decrypt = qcrypto_block_qcow_decrypt, | |
181 | .encrypt = qcrypto_block_qcow_encrypt, | |
182 | .has_format = qcrypto_block_qcow_has_format, | |
183 | }; |