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 "crypto/cipher.h"
  22
  23
  24 static size_t alg_key_len[QCRYPTO_CIPHER_ALG__MAX] = {
  25     [QCRYPTO_CIPHER_ALG_AES_128] = 16,
  26     [QCRYPTO_CIPHER_ALG_AES_192] = 24,
  27     [QCRYPTO_CIPHER_ALG_AES_256] = 32,
  28     [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
  29 };
  30
  31 static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
  32     [QCRYPTO_CIPHER_ALG_AES_128] = 16,
  33     [QCRYPTO_CIPHER_ALG_AES_192] = 16,
  34     [QCRYPTO_CIPHER_ALG_AES_256] = 16,
  35     [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
  36 };
  37
  38 static bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = {
  39     [QCRYPTO_CIPHER_MODE_ECB] = false,
  40     [QCRYPTO_CIPHER_MODE_CBC] = true,
  41 };
  42
  43
  44 size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg)
  45 {
  46     if (alg >= G_N_ELEMENTS(alg_key_len)) {
  47         return 0;
  48     }
  49     return alg_block_len[alg];
  50 }
  51
  52
  53 size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg)
  54 {
  55     if (alg >= G_N_ELEMENTS(alg_key_len)) {
  56         return 0;
  57     }
  58     return alg_key_len[alg];
  59 }
  60
  61
  62 size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg,
  63                                  QCryptoCipherMode mode)
  64 {
  65     if (alg >= G_N_ELEMENTS(alg_block_len)) {
  66         return 0;
  67     }
  68     if (mode >= G_N_ELEMENTS(mode_need_iv)) {
  69         return 0;
  70     }
  71
  72     if (mode_need_iv[mode]) {
  73         return alg_block_len[alg];
  74     }
  75     return 0;
  76 }
  77
  78
  79 static bool
  80 qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg,
  81                                    size_t nkey,
  82                                    Error **errp)
  83 {
  84     if ((unsigned)alg >= QCRYPTO_CIPHER_ALG__MAX) {
  85         error_setg(errp, "Cipher algorithm %d out of range",
  86                    alg);
  87         return false;
  88     }
  89
  90     if (alg_key_len[alg] != nkey) {
  91         error_setg(errp, "Cipher key length %zu should be %zu",
  92                    nkey, alg_key_len[alg]);
  93         return false;
  94     }
  95     return true;
  96 }
  97
  98 #if defined(CONFIG_GCRYPT) || defined(CONFIG_NETTLE)
  99 static uint8_t *
 100 qcrypto_cipher_munge_des_rfb_key(const uint8_t *key,
 101                                  size_t nkey)
 102 {
 103     uint8_t *ret = g_new0(uint8_t, nkey);
 104     size_t i;
 105     for (i = 0; i < nkey; i++) {
 106         uint8_t r = key[i];
 107         r = (r & 0xf0) >> 4 | (r & 0x0f) << 4;
 108         r = (r & 0xcc) >> 2 | (r & 0x33) << 2;
 109         r = (r & 0xaa) >> 1 | (r & 0x55) << 1;
 110         ret[i] = r;
 111     }
 112     return ret;
 113 }
 114 #endif /* CONFIG_GCRYPT || CONFIG_NETTLE */
 115
 116 #ifdef CONFIG_GCRYPT
 117 #include "crypto/cipher-gcrypt.c"
 118 #elif defined CONFIG_NETTLE
 119 #include "crypto/cipher-nettle.c"
 120 #else
 121 #include "crypto/cipher-builtin.c"
 122 #endif