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