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 2.1 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 "qemu/host-utils.h"
  23 #include "qapi/error.h"
  24 #include "crypto/cipher.h"
  25 #include "cipherpriv.h"
  26
  27
  28 static const size_t alg_key_len[QCRYPTO_CIPHER_ALG__MAX] = {
  29     [QCRYPTO_CIPHER_ALG_AES_128] = 16,
  30     [QCRYPTO_CIPHER_ALG_AES_192] = 24,
  31     [QCRYPTO_CIPHER_ALG_AES_256] = 32,
  32     [QCRYPTO_CIPHER_ALG_DES] = 8,
  33     [QCRYPTO_CIPHER_ALG_3DES] = 24,
  34     [QCRYPTO_CIPHER_ALG_CAST5_128] = 16,
  35     [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
  36     [QCRYPTO_CIPHER_ALG_SERPENT_192] = 24,
  37     [QCRYPTO_CIPHER_ALG_SERPENT_256] = 32,
  38     [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
  39     [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 24,
  40     [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 32,
  41 };
  42
  43 static const size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
  44     [QCRYPTO_CIPHER_ALG_AES_128] = 16,
  45     [QCRYPTO_CIPHER_ALG_AES_192] = 16,
  46     [QCRYPTO_CIPHER_ALG_AES_256] = 16,
  47     [QCRYPTO_CIPHER_ALG_DES] = 8,
  48     [QCRYPTO_CIPHER_ALG_3DES] = 8,
  49     [QCRYPTO_CIPHER_ALG_CAST5_128] = 8,
  50     [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
  51     [QCRYPTO_CIPHER_ALG_SERPENT_192] = 16,
  52     [QCRYPTO_CIPHER_ALG_SERPENT_256] = 16,
  53     [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
  54     [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 16,
  55     [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 16,
  56 };
  57
  58 static const bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = {
  59     [QCRYPTO_CIPHER_MODE_ECB] = false,
  60     [QCRYPTO_CIPHER_MODE_CBC] = true,
  61     [QCRYPTO_CIPHER_MODE_XTS] = true,
  62     [QCRYPTO_CIPHER_MODE_CTR] = true,
  63 };
  64
  65
  66 size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg)
  67 {
  68     assert(alg < G_N_ELEMENTS(alg_key_len));
  69     return alg_block_len[alg];
  70 }
  71
  72
  73 size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg)
  74 {
  75     assert(alg < G_N_ELEMENTS(alg_key_len));
  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 ||
 111             alg == QCRYPTO_CIPHER_ALG_3DES) {
 112             error_setg(errp, "XTS mode not compatible with DES/3DES");
 113             return false;
 114         }
 115         if (nkey % 2) {
 116             error_setg(errp, "XTS cipher key length should be a multiple of 2");
 117             return false;
 118         }
 119
 120         if (alg_key_len[alg] != (nkey / 2)) {
 121             error_setg(errp, "Cipher key length %zu should be %zu",
 122                        nkey, alg_key_len[alg] * 2);
 123             return false;
 124         }
 125     } else {
 126         if (alg_key_len[alg] != nkey) {
 127             error_setg(errp, "Cipher key length %zu should be %zu",
 128                        nkey, alg_key_len[alg]);
 129             return false;
 130         }
 131     }
 132     return true;
 133 }
 134
 135 #ifdef CONFIG_GCRYPT
 136 #include "cipher-gcrypt.c.inc"
 137 #elif defined CONFIG_NETTLE
 138 #include "cipher-nettle.c.inc"
 139 #elif defined CONFIG_GNUTLS_CRYPTO
 140 #include "cipher-gnutls.c.inc"
 141 #else
 142 #include "cipher-builtin.c.inc"
 143 #endif
 144
 145 QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
 146                                   QCryptoCipherMode mode,
 147                                   const uint8_t *key, size_t nkey,
 148                                   Error **errp)
 149 {
 150     QCryptoCipher *cipher = NULL;
 151
 152 #ifdef CONFIG_AF_ALG
 153     cipher = qcrypto_afalg_cipher_ctx_new(alg, mode, key, nkey, NULL);
 154 #endif
 155
 156     if (!cipher) {
 157         cipher = qcrypto_cipher_ctx_new(alg, mode, key, nkey, errp);
 158         if (!cipher) {
 159             return NULL;
 160         }
 161     }
 162
 163     cipher->alg = alg;
 164     cipher->mode = mode;
 165
 166     return cipher;
 167 }
 168
 169
 170 int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
 171                            const void *in,
 172                            void *out,
 173                            size_t len,
 174                            Error **errp)
 175 {
 176     const QCryptoCipherDriver *drv = cipher->driver;
 177     return drv->cipher_encrypt(cipher, in, out, len, errp);
 178 }
 179
 180
 181 int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
 182                            const void *in,
 183                            void *out,
 184                            size_t len,
 185                            Error **errp)
 186 {
 187     const QCryptoCipherDriver *drv = cipher->driver;
 188     return drv->cipher_decrypt(cipher, in, out, len, errp);
 189 }
 190
 191
 192 int qcrypto_cipher_setiv(QCryptoCipher *cipher,
 193                          const uint8_t *iv, size_t niv,
 194                          Error **errp)
 195 {
 196     const QCryptoCipherDriver *drv = cipher->driver;
 197     return drv->cipher_setiv(cipher, iv, niv, errp);
 198 }
 199
 200
 201 void qcrypto_cipher_free(QCryptoCipher *cipher)
 202 {
 203     if (cipher) {
 204         cipher->driver->cipher_free(cipher);
 205     }
 206 }