crypto/cipher.c

   1 /*
   2  * QEMU Crypto cipher algorithms
   3  *
   4  * Copyright (c) 2015 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 "crypto/cipher.h"
  23
  24
  25 static size_t alg_key_len[QCRYPTO_CIPHER_ALG__MAX] = {
  26     [QCRYPTO_CIPHER_ALG_AES_128] = 16,
  27     [QCRYPTO_CIPHER_ALG_AES_192] = 24,
  28     [QCRYPTO_CIPHER_ALG_AES_256] = 32,
  29     [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
  30     [QCRYPTO_CIPHER_ALG_CAST5_128] = 16,
  31     [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
  32     [QCRYPTO_CIPHER_ALG_SERPENT_192] = 24,
  33     [QCRYPTO_CIPHER_ALG_SERPENT_256] = 32,
  34     [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
  35     [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 24,
  36     [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 32,
  37 };
  38
  39 static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
  40     [QCRYPTO_CIPHER_ALG_AES_128] = 16,
  41     [QCRYPTO_CIPHER_ALG_AES_192] = 16,
  42     [QCRYPTO_CIPHER_ALG_AES_256] = 16,
  43     [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
  44     [QCRYPTO_CIPHER_ALG_CAST5_128] = 8,
  45     [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
  46     [QCRYPTO_CIPHER_ALG_SERPENT_192] = 16,
  47     [QCRYPTO_CIPHER_ALG_SERPENT_256] = 16,
  48     [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
  49     [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 16,
  50     [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 16,
  51 };
  52
  53 static bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = {
  54     [QCRYPTO_CIPHER_MODE_ECB] = false,
  55     [QCRYPTO_CIPHER_MODE_CBC] = true,
  56     [QCRYPTO_CIPHER_MODE_XTS] = true,
  57 };
  58
  59
  60 size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg)
  61 {
  62     if (alg >= G_N_ELEMENTS(alg_key_len)) {
  63         return 0;
  64     }
  65     return alg_block_len[alg];
  66 }
  67
  68
  69 size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg)
  70 {
  71     if (alg >= G_N_ELEMENTS(alg_key_len)) {
  72         return 0;
  73     }
  74     return alg_key_len[alg];
  75 }
  76
  77
  78 size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg,
  79                                  QCryptoCipherMode mode)
  80 {
  81     if (alg >= G_N_ELEMENTS(alg_block_len)) {
  82         return 0;
  83     }
  84     if (mode >= G_N_ELEMENTS(mode_need_iv)) {
  85         return 0;
  86     }
  87
  88     if (mode_need_iv[mode]) {
  89         return alg_block_len[alg];
  90     }
  91     return 0;
  92 }
  93
  94
  95 static bool
  96 qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg,
  97                                    QCryptoCipherMode mode,
  98                                    size_t nkey,
  99                                    Error **errp)
 100 {
 101     if ((unsigned)alg >= QCRYPTO_CIPHER_ALG__MAX) {
 102         error_setg(errp, "Cipher algorithm %d out of range",
 103                    alg);
 104         return false;
 105     }
 106
 107     if (mode == QCRYPTO_CIPHER_MODE_XTS) {
 108         if (alg == QCRYPTO_CIPHER_ALG_DES_RFB) {
 109             error_setg(errp, "XTS mode not compatible with DES-RFB");
 110             return false;
 111         }
 112         if (nkey % 2) {
 113             error_setg(errp, "XTS cipher key length should be a multiple of 2");
 114             return false;
 115         }
 116
 117         if (alg_key_len[alg] != (nkey / 2)) {
 118             error_setg(errp, "Cipher key length %zu should be %zu",
 119                        nkey, alg_key_len[alg] * 2);
 120             return false;
 121         }
 122     } else {
 123         if (alg_key_len[alg] != nkey) {
 124             error_setg(errp, "Cipher key length %zu should be %zu",
 125                        nkey, alg_key_len[alg]);
 126             return false;
 127         }
 128     }
 129     return true;
 130 }
 131
 132 #if defined(CONFIG_GCRYPT) || defined(CONFIG_NETTLE)
 133 static uint8_t *
 134 qcrypto_cipher_munge_des_rfb_key(const uint8_t *key,
 135                                  size_t nkey)
 136 {
 137     uint8_t *ret = g_new0(uint8_t, nkey);
 138     size_t i;
 139     for (i = 0; i < nkey; i++) {
 140         uint8_t r = key[i];
 141         r = (r & 0xf0) >> 4 | (r & 0x0f) << 4;
 142         r = (r & 0xcc) >> 2 | (r & 0x33) << 2;
 143         r = (r & 0xaa) >> 1 | (r & 0x55) << 1;
 144         ret[i] = r;
 145     }
 146     return ret;
 147 }
 148 #endif /* CONFIG_GCRYPT || CONFIG_NETTLE */
 149
 150 #ifdef CONFIG_GCRYPT
 151 #include "crypto/cipher-gcrypt.c"
 152 #elif defined CONFIG_NETTLE
 153 #include "crypto/cipher-nettle.c"
 154 #else
 155 #include "crypto/cipher-builtin.c"
 156 #endif