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_3DES] = 24,
  32     [QCRYPTO_CIPHER_ALG_CAST5_128] = 16,
  33     [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
  34     [QCRYPTO_CIPHER_ALG_SERPENT_192] = 24,
  35     [QCRYPTO_CIPHER_ALG_SERPENT_256] = 32,
  36     [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
  37     [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 24,
  38     [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 32,
  39 };
  40
  41 static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
  42     [QCRYPTO_CIPHER_ALG_AES_128] = 16,
  43     [QCRYPTO_CIPHER_ALG_AES_192] = 16,
  44     [QCRYPTO_CIPHER_ALG_AES_256] = 16,
  45     [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
  46     [QCRYPTO_CIPHER_ALG_3DES] = 8,
  47     [QCRYPTO_CIPHER_ALG_CAST5_128] = 8,
  48     [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
  49     [QCRYPTO_CIPHER_ALG_SERPENT_192] = 16,
  50     [QCRYPTO_CIPHER_ALG_SERPENT_256] = 16,
  51     [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
  52     [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 16,
  53     [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 16,
  54 };
  55
  56 static bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = {
  57     [QCRYPTO_CIPHER_MODE_ECB] = false,
  58     [QCRYPTO_CIPHER_MODE_CBC] = true,
  59     [QCRYPTO_CIPHER_MODE_XTS] = true,
  60     [QCRYPTO_CIPHER_MODE_CTR] = true,
  61 };
  62
  63
  64 size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg)
  65 {
  66     if (alg >= G_N_ELEMENTS(alg_key_len)) {
  67         return 0;
  68     }
  69     return alg_block_len[alg];
  70 }
  71
  72
  73 size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg)
  74 {
  75     if (alg >= G_N_ELEMENTS(alg_key_len)) {
  76         return 0;
  77     }
  78     return alg_key_len[alg];
  79 }
  80
  81
  82 size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg,
  83                                  QCryptoCipherMode mode)
  84 {
  85     if (alg >= G_N_ELEMENTS(alg_block_len)) {
  86         return 0;
  87     }
  88     if (mode >= G_N_ELEMENTS(mode_need_iv)) {
  89         return 0;
  90     }
  91
  92     if (mode_need_iv[mode]) {
  93         return alg_block_len[alg];
  94     }
  95     return 0;
  96 }
  97
  98
  99 static bool
 100 qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg,
 101                                    QCryptoCipherMode mode,
 102                                    size_t nkey,
 103                                    Error **errp)
 104 {
 105     if ((unsigned)alg >= QCRYPTO_CIPHER_ALG__MAX) {
 106         error_setg(errp, "Cipher algorithm %d out of range",
 107                    alg);
 108         return false;
 109     }
 110
 111     if (mode == QCRYPTO_CIPHER_MODE_XTS) {
 112         if (alg == QCRYPTO_CIPHER_ALG_DES_RFB
 113                 || alg == QCRYPTO_CIPHER_ALG_3DES) {
 114             error_setg(errp, "XTS mode not compatible with DES-RFB/3DES");
 115             return false;
 116         }
 117         if (nkey % 2) {
 118             error_setg(errp, "XTS cipher key length should be a multiple of 2");
 119             return false;
 120         }
 121
 122         if (alg_key_len[alg] != (nkey / 2)) {
 123             error_setg(errp, "Cipher key length %zu should be %zu",
 124                        nkey, alg_key_len[alg] * 2);
 125             return false;
 126         }
 127     } else {
 128         if (alg_key_len[alg] != nkey) {
 129             error_setg(errp, "Cipher key length %zu should be %zu",
 130                        nkey, alg_key_len[alg]);
 131             return false;
 132         }
 133     }
 134     return true;
 135 }
 136
 137 #if defined(CONFIG_GCRYPT) || defined(CONFIG_NETTLE)
 138 static uint8_t *
 139 qcrypto_cipher_munge_des_rfb_key(const uint8_t *key,
 140                                  size_t nkey)
 141 {
 142     uint8_t *ret = g_new0(uint8_t, nkey);
 143     size_t i;
 144     for (i = 0; i < nkey; i++) {
 145         uint8_t r = key[i];
 146         r = (r & 0xf0) >> 4 | (r & 0x0f) << 4;
 147         r = (r & 0xcc) >> 2 | (r & 0x33) << 2;
 148         r = (r & 0xaa) >> 1 | (r & 0x55) << 1;
 149         ret[i] = r;
 150     }
 151     return ret;
 152 }
 153 #endif /* CONFIG_GCRYPT || CONFIG_NETTLE */
 154
 155 #ifdef CONFIG_GCRYPT
 156 #include "crypto/cipher-gcrypt.c"
 157 #elif defined CONFIG_NETTLE
 158 #include "crypto/cipher-nettle.c"
 159 #else
 160 #include "crypto/cipher-builtin.c"
 161 #endif