Merge remote-tracking branch 'remotes/kraxel/tags/pull-vga-20170103-1' into staging
[qemu.git] / crypto / ivgen-essiv.c
1 /*
2 * QEMU Crypto block IV generator - essiv
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 #include "qemu/osdep.h"
22 #include "qapi/error.h"
23 #include "qemu/bswap.h"
24 #include "crypto/ivgen-essiv.h"
25
26 typedef struct QCryptoIVGenESSIV QCryptoIVGenESSIV;
27 struct QCryptoIVGenESSIV {
28 QCryptoCipher *cipher;
29 };
30
31 static int qcrypto_ivgen_essiv_init(QCryptoIVGen *ivgen,
32 const uint8_t *key, size_t nkey,
33 Error **errp)
34 {
35 uint8_t *salt;
36 size_t nhash;
37 size_t nsalt;
38 QCryptoIVGenESSIV *essiv = g_new0(QCryptoIVGenESSIV, 1);
39
40 /* Not necessarily the same as nkey */
41 nsalt = qcrypto_cipher_get_key_len(ivgen->cipher);
42
43 nhash = qcrypto_hash_digest_len(ivgen->hash);
44 /* Salt must be larger of hash size or key size */
45 salt = g_new0(uint8_t, MAX(nhash, nsalt));
46
47 if (qcrypto_hash_bytes(ivgen->hash, (const gchar *)key, nkey,
48 &salt, &nhash,
49 errp) < 0) {
50 g_free(essiv);
51 return -1;
52 }
53
54 /* Now potentially truncate salt to match cipher key len */
55 essiv->cipher = qcrypto_cipher_new(ivgen->cipher,
56 QCRYPTO_CIPHER_MODE_ECB,
57 salt, MIN(nhash, nsalt),
58 errp);
59 if (!essiv->cipher) {
60 g_free(essiv);
61 g_free(salt);
62 return -1;
63 }
64
65 g_free(salt);
66 ivgen->private = essiv;
67
68 return 0;
69 }
70
71 static int qcrypto_ivgen_essiv_calculate(QCryptoIVGen *ivgen,
72 uint64_t sector,
73 uint8_t *iv, size_t niv,
74 Error **errp)
75 {
76 QCryptoIVGenESSIV *essiv = ivgen->private;
77 size_t ndata = qcrypto_cipher_get_block_len(ivgen->cipher);
78 uint8_t *data = g_new(uint8_t, ndata);
79
80 sector = cpu_to_le64(sector);
81 memcpy(data, (uint8_t *)&sector, ndata);
82 if (sizeof(sector) < ndata) {
83 memset(data + sizeof(sector), 0, ndata - sizeof(sector));
84 }
85
86 if (qcrypto_cipher_encrypt(essiv->cipher,
87 data,
88 data,
89 ndata,
90 errp) < 0) {
91 g_free(data);
92 return -1;
93 }
94
95 if (ndata > niv) {
96 ndata = niv;
97 }
98 memcpy(iv, data, ndata);
99 if (ndata < niv) {
100 memset(iv + ndata, 0, niv - ndata);
101 }
102 g_free(data);
103 return 0;
104 }
105
106 static void qcrypto_ivgen_essiv_cleanup(QCryptoIVGen *ivgen)
107 {
108 QCryptoIVGenESSIV *essiv = ivgen->private;
109
110 qcrypto_cipher_free(essiv->cipher);
111 g_free(essiv);
112 }
113
114
115 struct QCryptoIVGenDriver qcrypto_ivgen_essiv = {
116 .init = qcrypto_ivgen_essiv_init,
117 .calculate = qcrypto_ivgen_essiv_calculate,
118 .cleanup = qcrypto_ivgen_essiv_cleanup,
119 };
120