Daniel P. Berrange | 7d96901 | 2015-10-24 11:44:13 +0100 | [diff] [blame] | 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" |
Markus Armbruster | da34e65 | 2016-03-14 09:01:28 +0100 | [diff] [blame] | 28 | #include "qapi/error.h" |
Daniel P. Berrange | 7d96901 | 2015-10-24 11:44:13 +0100 | [diff] [blame] | 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 | |
| 83 | block->payload_offset = 0; |
| 84 | |
| 85 | return 0; |
| 86 | |
| 87 | fail: |
| 88 | qcrypto_cipher_free(block->cipher); |
| 89 | qcrypto_ivgen_free(block->ivgen); |
| 90 | return ret; |
| 91 | } |
| 92 | |
| 93 | |
| 94 | static int |
| 95 | qcrypto_block_qcow_open(QCryptoBlock *block, |
| 96 | QCryptoBlockOpenOptions *options, |
| 97 | QCryptoBlockReadFunc readfunc G_GNUC_UNUSED, |
| 98 | void *opaque G_GNUC_UNUSED, |
| 99 | unsigned int flags, |
| 100 | Error **errp) |
| 101 | { |
| 102 | if (flags & QCRYPTO_BLOCK_OPEN_NO_IO) { |
| 103 | return 0; |
| 104 | } else { |
| 105 | if (!options->u.qcow.key_secret) { |
| 106 | error_setg(errp, |
| 107 | "Parameter 'key-secret' is required for cipher"); |
| 108 | return -1; |
| 109 | } |
| 110 | return qcrypto_block_qcow_init(block, |
| 111 | options->u.qcow.key_secret, errp); |
| 112 | } |
| 113 | } |
| 114 | |
| 115 | |
| 116 | static int |
| 117 | qcrypto_block_qcow_create(QCryptoBlock *block, |
| 118 | QCryptoBlockCreateOptions *options, |
| 119 | QCryptoBlockInitFunc initfunc G_GNUC_UNUSED, |
| 120 | QCryptoBlockWriteFunc writefunc G_GNUC_UNUSED, |
| 121 | void *opaque G_GNUC_UNUSED, |
| 122 | Error **errp) |
| 123 | { |
| 124 | if (!options->u.qcow.key_secret) { |
| 125 | error_setg(errp, "Parameter 'key-secret' is required for cipher"); |
| 126 | return -1; |
| 127 | } |
| 128 | /* QCow2 has no special header, since everything is hardwired */ |
| 129 | return qcrypto_block_qcow_init(block, options->u.qcow.key_secret, errp); |
| 130 | } |
| 131 | |
| 132 | |
| 133 | static void |
| 134 | qcrypto_block_qcow_cleanup(QCryptoBlock *block) |
| 135 | { |
| 136 | } |
| 137 | |
| 138 | |
| 139 | static int |
| 140 | qcrypto_block_qcow_decrypt(QCryptoBlock *block, |
| 141 | uint64_t startsector, |
| 142 | uint8_t *buf, |
| 143 | size_t len, |
| 144 | Error **errp) |
| 145 | { |
| 146 | return qcrypto_block_decrypt_helper(block->cipher, |
| 147 | block->niv, block->ivgen, |
| 148 | QCRYPTO_BLOCK_QCOW_SECTOR_SIZE, |
| 149 | startsector, buf, len, errp); |
| 150 | } |
| 151 | |
| 152 | |
| 153 | static int |
| 154 | qcrypto_block_qcow_encrypt(QCryptoBlock *block, |
| 155 | uint64_t startsector, |
| 156 | uint8_t *buf, |
| 157 | size_t len, |
| 158 | Error **errp) |
| 159 | { |
| 160 | return qcrypto_block_encrypt_helper(block->cipher, |
| 161 | block->niv, block->ivgen, |
| 162 | QCRYPTO_BLOCK_QCOW_SECTOR_SIZE, |
| 163 | startsector, buf, len, errp); |
| 164 | } |
| 165 | |
| 166 | |
| 167 | const QCryptoBlockDriver qcrypto_block_driver_qcow = { |
| 168 | .open = qcrypto_block_qcow_open, |
| 169 | .create = qcrypto_block_qcow_create, |
| 170 | .cleanup = qcrypto_block_qcow_cleanup, |
| 171 | .decrypt = qcrypto_block_qcow_decrypt, |
| 172 | .encrypt = qcrypto_block_qcow_encrypt, |
| 173 | .has_format = qcrypto_block_qcow_has_format, |
| 174 | }; |