qxl: check release info object
[qemu.git] / crypto / afsplit.c
1 /*
2 * QEMU Crypto anti forensic information splitter
3 *
4 * Copyright (c) 2015-2016 Red Hat, Inc.
5 *
6 * Derived from cryptsetup package lib/luks1/af.c
7 *
8 * Copyright (C) 2004, Clemens Fruhwirth <clemens@endorphin.org>
9 * Copyright (C) 2009-2012, Red Hat, Inc. All rights reserved.
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version 2
14 * of the License, or (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, see <http://www.gnu.org/licenses/>.
23 */
24
25 #include "qemu/osdep.h"
26 #include "qemu/bswap.h"
27 #include "crypto/afsplit.h"
28 #include "crypto/random.h"
29
30
31 static void qcrypto_afsplit_xor(size_t blocklen,
32 const uint8_t *in1,
33 const uint8_t *in2,
34 uint8_t *out)
35 {
36 size_t i;
37 for (i = 0; i < blocklen; i++) {
38 out[i] = in1[i] ^ in2[i];
39 }
40 }
41
42
43 static int qcrypto_afsplit_hash(QCryptoHashAlgorithm hash,
44 size_t blocklen,
45 uint8_t *block,
46 Error **errp)
47 {
48 size_t digestlen = qcrypto_hash_digest_len(hash);
49
50 size_t hashcount = blocklen / digestlen;
51 size_t finallen = blocklen % digestlen;
52 uint32_t i;
53
54 if (finallen) {
55 hashcount++;
56 } else {
57 finallen = digestlen;
58 }
59
60 for (i = 0; i < hashcount; i++) {
61 uint8_t *out = NULL;
62 size_t outlen = 0;
63 uint32_t iv = cpu_to_be32(i);
64 struct iovec in[] = {
65 { .iov_base = &iv,
66 .iov_len = sizeof(iv) },
67 { .iov_base = block + (i * digestlen),
68 .iov_len = (i == (hashcount - 1)) ? finallen : digestlen },
69 };
70
71 if (qcrypto_hash_bytesv(hash,
72 in,
73 G_N_ELEMENTS(in),
74 &out, &outlen,
75 errp) < 0) {
76 return -1;
77 }
78
79 assert(outlen == digestlen);
80 memcpy(block + (i * digestlen), out,
81 (i == (hashcount - 1)) ? finallen : digestlen);
82 g_free(out);
83 }
84
85 return 0;
86 }
87
88
89 int qcrypto_afsplit_encode(QCryptoHashAlgorithm hash,
90 size_t blocklen,
91 uint32_t stripes,
92 const uint8_t *in,
93 uint8_t *out,
94 Error **errp)
95 {
96 uint8_t *block = g_new0(uint8_t, blocklen);
97 size_t i;
98 int ret = -1;
99
100 for (i = 0; i < (stripes - 1); i++) {
101 if (qcrypto_random_bytes(out + (i * blocklen), blocklen, errp) < 0) {
102 goto cleanup;
103 }
104
105 qcrypto_afsplit_xor(blocklen,
106 out + (i * blocklen),
107 block,
108 block);
109 if (qcrypto_afsplit_hash(hash, blocklen, block,
110 errp) < 0) {
111 goto cleanup;
112 }
113 }
114 qcrypto_afsplit_xor(blocklen,
115 in,
116 block,
117 out + (i * blocklen));
118 ret = 0;
119
120 cleanup:
121 g_free(block);
122 return ret;
123 }
124
125
126 int qcrypto_afsplit_decode(QCryptoHashAlgorithm hash,
127 size_t blocklen,
128 uint32_t stripes,
129 const uint8_t *in,
130 uint8_t *out,
131 Error **errp)
132 {
133 uint8_t *block = g_new0(uint8_t, blocklen);
134 size_t i;
135 int ret = -1;
136
137 for (i = 0; i < (stripes - 1); i++) {
138 qcrypto_afsplit_xor(blocklen,
139 in + (i * blocklen),
140 block,
141 block);
142 if (qcrypto_afsplit_hash(hash, blocklen, block,
143 errp) < 0) {
144 goto cleanup;
145 }
146 }
147
148 qcrypto_afsplit_xor(blocklen,
149 in + (i * blocklen),
150 block,
151 out);
152
153 ret = 0;
154
155 cleanup:
156 g_free(block);
157 return ret;
158 }