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