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 2.1 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" |
28 | #include "qapi/error.h" |
29 | |
30 | #include "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 | size_t n_threads, |
48 | Error **errp) |
49 | { |
50 | char *password; |
51 | int ret; |
52 | uint8_t keybuf[16]; |
53 | int len; |
54 | |
55 | memset(keybuf, 0, 16); |
56 | |
57 | password = qcrypto_secret_lookup_as_utf8(keysecret, errp); |
58 | if (!password) { |
59 | return -1; |
60 | } |
61 | |
62 | len = strlen(password); |
63 | memcpy(keybuf, password, MIN(len, sizeof(keybuf))); |
64 | g_free(password); |
65 | |
66 | block->niv = qcrypto_cipher_get_iv_len(QCRYPTO_CIPHER_ALG_AES_128, |
67 | QCRYPTO_CIPHER_MODE_CBC); |
68 | block->ivgen = qcrypto_ivgen_new(QCRYPTO_IVGEN_ALG_PLAIN64, |
69 | 0, 0, NULL, 0, errp); |
70 | if (!block->ivgen) { |
71 | ret = -ENOTSUP; |
72 | goto fail; |
73 | } |
74 | |
75 | ret = qcrypto_block_init_cipher(block, QCRYPTO_CIPHER_ALG_AES_128, |
76 | QCRYPTO_CIPHER_MODE_CBC, |
77 | keybuf, G_N_ELEMENTS(keybuf), |
78 | n_threads, errp); |
79 | if (ret < 0) { |
80 | ret = -ENOTSUP; |
81 | goto fail; |
82 | } |
83 | |
84 | block->sector_size = QCRYPTO_BLOCK_QCOW_SECTOR_SIZE; |
85 | block->payload_offset = 0; |
86 | |
87 | return 0; |
88 | |
89 | fail: |
90 | qcrypto_block_free_cipher(block); |
91 | qcrypto_ivgen_free(block->ivgen); |
92 | return ret; |
93 | } |
94 | |
95 | |
96 | static int |
97 | qcrypto_block_qcow_open(QCryptoBlock *block, |
98 | QCryptoBlockOpenOptions *options, |
99 | const char *optprefix, |
100 | QCryptoBlockReadFunc readfunc G_GNUC_UNUSED, |
101 | void *opaque G_GNUC_UNUSED, |
102 | unsigned int flags, |
103 | size_t n_threads, |
104 | Error **errp) |
105 | { |
106 | if (flags & QCRYPTO_BLOCK_OPEN_NO_IO) { |
107 | block->sector_size = QCRYPTO_BLOCK_QCOW_SECTOR_SIZE; |
108 | block->payload_offset = 0; |
109 | return 0; |
110 | } else { |
111 | if (!options->u.qcow.key_secret) { |
112 | error_setg(errp, |
113 | "Parameter '%skey-secret' is required for cipher" , |
114 | optprefix ? optprefix : "" ); |
115 | return -1; |
116 | } |
117 | return qcrypto_block_qcow_init(block, options->u.qcow.key_secret, |
118 | n_threads, errp); |
119 | } |
120 | } |
121 | |
122 | |
123 | static int |
124 | qcrypto_block_qcow_create(QCryptoBlock *block, |
125 | QCryptoBlockCreateOptions *options, |
126 | const char *optprefix, |
127 | QCryptoBlockInitFunc initfunc G_GNUC_UNUSED, |
128 | QCryptoBlockWriteFunc writefunc G_GNUC_UNUSED, |
129 | void *opaque G_GNUC_UNUSED, |
130 | Error **errp) |
131 | { |
132 | if (!options->u.qcow.key_secret) { |
133 | error_setg(errp, "Parameter '%skey-secret' is required for cipher" , |
134 | optprefix ? optprefix : "" ); |
135 | return -1; |
136 | } |
137 | /* QCow2 has no special header, since everything is hardwired */ |
138 | return qcrypto_block_qcow_init(block, options->u.qcow.key_secret, 1, errp); |
139 | } |
140 | |
141 | |
142 | static void |
143 | qcrypto_block_qcow_cleanup(QCryptoBlock *block) |
144 | { |
145 | } |
146 | |
147 | |
148 | static int |
149 | qcrypto_block_qcow_decrypt(QCryptoBlock *block, |
150 | uint64_t offset, |
151 | uint8_t *buf, |
152 | size_t len, |
153 | Error **errp) |
154 | { |
155 | assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE)); |
156 | assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE)); |
157 | return qcrypto_block_decrypt_helper(block, |
158 | QCRYPTO_BLOCK_QCOW_SECTOR_SIZE, |
159 | offset, buf, len, errp); |
160 | } |
161 | |
162 | |
163 | static int |
164 | qcrypto_block_qcow_encrypt(QCryptoBlock *block, |
165 | uint64_t offset, |
166 | uint8_t *buf, |
167 | size_t len, |
168 | Error **errp) |
169 | { |
170 | assert(QEMU_IS_ALIGNED(offset, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE)); |
171 | assert(QEMU_IS_ALIGNED(len, QCRYPTO_BLOCK_QCOW_SECTOR_SIZE)); |
172 | return qcrypto_block_encrypt_helper(block, |
173 | QCRYPTO_BLOCK_QCOW_SECTOR_SIZE, |
174 | offset, buf, len, errp); |
175 | } |
176 | |
177 | |
178 | const QCryptoBlockDriver qcrypto_block_driver_qcow = { |
179 | .open = qcrypto_block_qcow_open, |
180 | .create = qcrypto_block_qcow_create, |
181 | .cleanup = qcrypto_block_qcow_cleanup, |
182 | .decrypt = qcrypto_block_qcow_decrypt, |
183 | .encrypt = qcrypto_block_qcow_encrypt, |
184 | .has_format = qcrypto_block_qcow_has_format, |
185 | }; |
186 | |