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_RFB] = 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_RFB] = 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_RFB
 111                 || alg == QCRYPTO_CIPHER_ALG_3DES) {
 112             error_setg(errp, "XTS mode not compatible with DES-RFB/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 #if defined(CONFIG_GCRYPT) || defined(CONFIG_NETTLE)
 136 static uint8_t *
 137 qcrypto_cipher_munge_des_rfb_key(const uint8_t *key,
 138                                  size_t nkey)
 139 {
 140     uint8_t *ret = g_new0(uint8_t, nkey);
 141     size_t i;
 142     for (i = 0; i < nkey; i++) {
 143         uint8_t r = key[i];
 144         r = (r & 0xf0) >> 4 | (r & 0x0f) << 4;
 145         r = (r & 0xcc) >> 2 | (r & 0x33) << 2;
 146         r = (r & 0xaa) >> 1 | (r & 0x55) << 1;
 147         ret[i] = r;
 148     }
 149     return ret;
 150 }
 151 #endif /* CONFIG_GCRYPT || CONFIG_NETTLE */
 152
 153 #ifdef CONFIG_GCRYPT
 154 #include "cipher-gcrypt.c.inc"
 155 #elif defined CONFIG_NETTLE
 156 #include "cipher-nettle.c.inc"
 157 #else
 158 #include "cipher-builtin.c.inc"
 159 #endif
 160
 161 QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
 162                                   QCryptoCipherMode mode,
 163                                   const uint8_t *key, size_t nkey,
 164                                   Error **errp)
 165 {
 166     QCryptoCipher *cipher = NULL;
 167
 168 #ifdef CONFIG_AF_ALG
 169     cipher = qcrypto_afalg_cipher_ctx_new(alg, mode, key, nkey, NULL);
 170 #endif
 171
 172     if (!cipher) {
 173         cipher = qcrypto_cipher_ctx_new(alg, mode, key, nkey, errp);
 174         if (!cipher) {
 175             return NULL;
 176         }
 177     }
 178
 179     cipher->alg = alg;
 180     cipher->mode = mode;
 181
 182     return cipher;
 183 }
 184
 185
 186 int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
 187                            const void *in,
 188                            void *out,
 189                            size_t len,
 190                            Error **errp)
 191 {
 192     const QCryptoCipherDriver *drv = cipher->driver;
 193     return drv->cipher_encrypt(cipher, in, out, len, errp);
 194 }
 195
 196
 197 int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
 198                            const void *in,
 199                            void *out,
 200                            size_t len,
 201                            Error **errp)
 202 {
 203     const QCryptoCipherDriver *drv = cipher->driver;
 204     return drv->cipher_decrypt(cipher, in, out, len, errp);
 205 }
 206
 207
 208 int qcrypto_cipher_setiv(QCryptoCipher *cipher,
 209                          const uint8_t *iv, size_t niv,
 210                          Error **errp)
 211 {
 212     const QCryptoCipherDriver *drv = cipher->driver;
 213     return drv->cipher_setiv(cipher, iv, niv, errp);
 214 }
 215
 216
 217 void qcrypto_cipher_free(QCryptoCipher *cipher)
 218 {
 219     if (cipher) {
 220         cipher->driver->cipher_free(cipher);
 221     }
 222 }