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 };
  59
  60
  61 size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg)
  62 {
  63     if (alg >= G_N_ELEMENTS(alg_key_len)) {
  64         return 0;
  65     }
  66     return alg_block_len[alg];
  67 }
  68
  69
  70 size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg)
  71 {
  72     if (alg >= G_N_ELEMENTS(alg_key_len)) {
  73         return 0;
  74     }
  75     return alg_key_len[alg];
  76 }
  77
  78
  79 size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg,
  80                                  QCryptoCipherMode mode)
  81 {
  82     if (alg >= G_N_ELEMENTS(alg_block_len)) {
  83         return 0;
  84     }
  85     if (mode >= G_N_ELEMENTS(mode_need_iv)) {
  86         return 0;
  87     }
  88
  89     if (mode_need_iv[mode]) {
  90         return alg_block_len[alg];
  91     }
  92     return 0;
  93 }
  94
  95
  96 static bool
  97 qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg,
  98                                    QCryptoCipherMode mode,
  99                                    size_t nkey,
 100                                    Error **errp)
 101 {
 102     if ((unsigned)alg >= QCRYPTO_CIPHER_ALG__MAX) {
 103         error_setg(errp, "Cipher algorithm %d out of range",
 104                    alg);
 105         return false;
 106     }
 107
 108     if (mode == QCRYPTO_CIPHER_MODE_XTS) {
 109         if (alg == QCRYPTO_CIPHER_ALG_DES_RFB) {
 110             error_setg(errp, "XTS mode not compatible with DES-RFB");
 111             return false;
 112         }
 113         if (nkey % 2) {
 114             error_setg(errp, "XTS cipher key length should be a multiple of 2");
 115             return false;
 116         }
 117
 118         if (alg_key_len[alg] != (nkey / 2)) {
 119             error_setg(errp, "Cipher key length %zu should be %zu",
 120                        nkey, alg_key_len[alg] * 2);
 121             return false;
 122         }
 123     } else {
 124         if (alg_key_len[alg] != nkey) {
 125             error_setg(errp, "Cipher key length %zu should be %zu",
 126                        nkey, alg_key_len[alg]);
 127             return false;
 128         }
 129     }
 130     return true;
 131 }
 132
 133 #if defined(CONFIG_GCRYPT) || defined(CONFIG_NETTLE)
 134 static uint8_t *
 135 qcrypto_cipher_munge_des_rfb_key(const uint8_t *key,
 136                                  size_t nkey)
 137 {
 138     uint8_t *ret = g_new0(uint8_t, nkey);
 139     size_t i;
 140     for (i = 0; i < nkey; i++) {
 141         uint8_t r = key[i];
 142         r = (r & 0xf0) >> 4 | (r & 0x0f) << 4;
 143         r = (r & 0xcc) >> 2 | (r & 0x33) << 2;
 144         r = (r & 0xaa) >> 1 | (r & 0x55) << 1;
 145         ret[i] = r;
 146     }
 147     return ret;
 148 }
 149 #endif /* CONFIG_GCRYPT || CONFIG_NETTLE */
 150
 151 #ifdef CONFIG_GCRYPT
 152 #include "crypto/cipher-gcrypt.c"
 153 #elif defined CONFIG_NETTLE
 154 #include "crypto/cipher-nettle.c"
 155 #else
 156 #include "crypto/cipher-builtin.c"
 157 #endif