summaryrefslogtreecommitdiff
path: root/crypto/cipher.c
blob: a9bca41302fd8f1a1433c1b5807311458240673e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
/*
 * QEMU Crypto cipher algorithms
 *
 * Copyright (c) 2015 Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "qemu/osdep.h"
#include "qapi/error.h"
#include "crypto/cipher.h"


static size_t alg_key_len[QCRYPTO_CIPHER_ALG__MAX] = {
    [QCRYPTO_CIPHER_ALG_AES_128] = 16,
    [QCRYPTO_CIPHER_ALG_AES_192] = 24,
    [QCRYPTO_CIPHER_ALG_AES_256] = 32,
    [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
    [QCRYPTO_CIPHER_ALG_CAST5_128] = 16,
    [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
    [QCRYPTO_CIPHER_ALG_SERPENT_192] = 24,
    [QCRYPTO_CIPHER_ALG_SERPENT_256] = 32,
    [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
    [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 24,
    [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 32,
};

static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
    [QCRYPTO_CIPHER_ALG_AES_128] = 16,
    [QCRYPTO_CIPHER_ALG_AES_192] = 16,
    [QCRYPTO_CIPHER_ALG_AES_256] = 16,
    [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
    [QCRYPTO_CIPHER_ALG_CAST5_128] = 8,
    [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
    [QCRYPTO_CIPHER_ALG_SERPENT_192] = 16,
    [QCRYPTO_CIPHER_ALG_SERPENT_256] = 16,
    [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
    [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 16,
    [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 16,
};

static bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = {
    [QCRYPTO_CIPHER_MODE_ECB] = false,
    [QCRYPTO_CIPHER_MODE_CBC] = true,
    [QCRYPTO_CIPHER_MODE_XTS] = true,
    [QCRYPTO_CIPHER_MODE_CTR] = true,
};


size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg)
{
    if (alg >= G_N_ELEMENTS(alg_key_len)) {
        return 0;
    }
    return alg_block_len[alg];
}


size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg)
{
    if (alg >= G_N_ELEMENTS(alg_key_len)) {
        return 0;
    }
    return alg_key_len[alg];
}


size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg,
                                 QCryptoCipherMode mode)
{
    if (alg >= G_N_ELEMENTS(alg_block_len)) {
        return 0;
    }
    if (mode >= G_N_ELEMENTS(mode_need_iv)) {
        return 0;
    }

    if (mode_need_iv[mode]) {
        return alg_block_len[alg];
    }
    return 0;
}


static bool
qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg,
                                   QCryptoCipherMode mode,
                                   size_t nkey,
                                   Error **errp)
{
    if ((unsigned)alg >= QCRYPTO_CIPHER_ALG__MAX) {
        error_setg(errp, "Cipher algorithm %d out of range",
                   alg);
        return false;
    }

    if (mode == QCRYPTO_CIPHER_MODE_XTS) {
        if (alg == QCRYPTO_CIPHER_ALG_DES_RFB) {
            error_setg(errp, "XTS mode not compatible with DES-RFB");
            return false;
        }
        if (nkey % 2) {
            error_setg(errp, "XTS cipher key length should be a multiple of 2");
            return false;
        }

        if (alg_key_len[alg] != (nkey / 2)) {
            error_setg(errp, "Cipher key length %zu should be %zu",
                       nkey, alg_key_len[alg] * 2);
            return false;
        }
    } else {
        if (alg_key_len[alg] != nkey) {
            error_setg(errp, "Cipher key length %zu should be %zu",
                       nkey, alg_key_len[alg]);
            return false;
        }
    }
    return true;
}

#if defined(CONFIG_GCRYPT) || defined(CONFIG_NETTLE)
static uint8_t *
qcrypto_cipher_munge_des_rfb_key(const uint8_t *key,
                                 size_t nkey)
{
    uint8_t *ret = g_new0(uint8_t, nkey);
    size_t i;
    for (i = 0; i < nkey; i++) {
        uint8_t r = key[i];
        r = (r & 0xf0) >> 4 | (r & 0x0f) << 4;
        r = (r & 0xcc) >> 2 | (r & 0x33) << 2;
        r = (r & 0xaa) >> 1 | (r & 0x55) << 1;
        ret[i] = r;
    }
    return ret;
}
#endif /* CONFIG_GCRYPT || CONFIG_NETTLE */

#ifdef CONFIG_GCRYPT
#include "crypto/cipher-gcrypt.c"
#elif defined CONFIG_NETTLE
#include "crypto/cipher-nettle.c"
#else
#include "crypto/cipher-builtin.c"
#endif