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 #include "cipherpriv.h"
  25
  26
  27 static size_t alg_key_len[QCRYPTO_CIPHER_ALG__MAX] = {
  28     [QCRYPTO_CIPHER_ALG_AES_128] = 16,
  29     [QCRYPTO_CIPHER_ALG_AES_192] = 24,
  30     [QCRYPTO_CIPHER_ALG_AES_256] = 32,
  31     [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
  32     [QCRYPTO_CIPHER_ALG_3DES] = 24,
  33     [QCRYPTO_CIPHER_ALG_CAST5_128] = 16,
  34     [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
  35     [QCRYPTO_CIPHER_ALG_SERPENT_192] = 24,
  36     [QCRYPTO_CIPHER_ALG_SERPENT_256] = 32,
  37     [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
  38     [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 24,
  39     [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 32,
  40 };
  41
  42 static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
  43     [QCRYPTO_CIPHER_ALG_AES_128] = 16,
  44     [QCRYPTO_CIPHER_ALG_AES_192] = 16,
  45     [QCRYPTO_CIPHER_ALG_AES_256] = 16,
  46     [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
  47     [QCRYPTO_CIPHER_ALG_3DES] = 8,
  48     [QCRYPTO_CIPHER_ALG_CAST5_128] = 8,
  49     [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
  50     [QCRYPTO_CIPHER_ALG_SERPENT_192] = 16,
  51     [QCRYPTO_CIPHER_ALG_SERPENT_256] = 16,
  52     [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
  53     [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 16,
  54     [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 16,
  55 };
  56
  57 static bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = {
  58     [QCRYPTO_CIPHER_MODE_ECB] = false,
  59     [QCRYPTO_CIPHER_MODE_CBC] = true,
  60     [QCRYPTO_CIPHER_MODE_XTS] = true,
  61     [QCRYPTO_CIPHER_MODE_CTR] = true,
  62 };
  63
  64
  65 size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg)
  66 {
  67     assert(alg < G_N_ELEMENTS(alg_key_len));
  68     return alg_block_len[alg];
  69 }
  70
  71
  72 size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg)
  73 {
  74     assert(alg < G_N_ELEMENTS(alg_key_len));
  75     return alg_key_len[alg];
  76 }
  77
  78
  79 size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg,
  80                                  QCryptoCipherMode mode)
  81 {
  82     if (alg >= G_N_ELEMENTS(alg_block_len)) {
  83         return 0;
  84     }
  85     if (mode >= G_N_ELEMENTS(mode_need_iv)) {
  86         return 0;
  87     }
  88
  89     if (mode_need_iv[mode]) {
  90         return alg_block_len[alg];
  91     }
  92     return 0;
  93 }
  94
  95
  96 static bool
  97 qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg,
  98                                    QCryptoCipherMode mode,
  99                                    size_t nkey,
 100                                    Error **errp)
 101 {
 102     if ((unsigned)alg >= QCRYPTO_CIPHER_ALG__MAX) {
 103         error_setg(errp, "Cipher algorithm %d out of range",
 104                    alg);
 105         return false;
 106     }
 107
 108     if (mode == QCRYPTO_CIPHER_MODE_XTS) {
 109         if (alg == QCRYPTO_CIPHER_ALG_DES_RFB
 110                 || alg == QCRYPTO_CIPHER_ALG_3DES) {
 111             error_setg(errp, "XTS mode not compatible with DES-RFB/3DES");
 112             return false;
 113         }
 114         if (nkey % 2) {
 115             error_setg(errp, "XTS cipher key length should be a multiple of 2");
 116             return false;
 117         }
 118
 119         if (alg_key_len[alg] != (nkey / 2)) {
 120             error_setg(errp, "Cipher key length %zu should be %zu",
 121                        nkey, alg_key_len[alg] * 2);
 122             return false;
 123         }
 124     } else {
 125         if (alg_key_len[alg] != nkey) {
 126             error_setg(errp, "Cipher key length %zu should be %zu",
 127                        nkey, alg_key_len[alg]);
 128             return false;
 129         }
 130     }
 131     return true;
 132 }
 133
 134 #if defined(CONFIG_GCRYPT) || defined(CONFIG_NETTLE)
 135 static uint8_t *
 136 qcrypto_cipher_munge_des_rfb_key(const uint8_t *key,
 137                                  size_t nkey)
 138 {
 139     uint8_t *ret = g_new0(uint8_t, nkey);
 140     size_t i;
 141     for (i = 0; i < nkey; i++) {
 142         uint8_t r = key[i];
 143         r = (r & 0xf0) >> 4 | (r & 0x0f) << 4;
 144         r = (r & 0xcc) >> 2 | (r & 0x33) << 2;
 145         r = (r & 0xaa) >> 1 | (r & 0x55) << 1;
 146         ret[i] = r;
 147     }
 148     return ret;
 149 }
 150 #endif /* CONFIG_GCRYPT || CONFIG_NETTLE */
 151
 152 #ifdef CONFIG_GCRYPT
 153 #include "crypto/cipher-gcrypt.c"
 154 #elif defined CONFIG_NETTLE
 155 #include "crypto/cipher-nettle.c"
 156 #else
 157 #include "crypto/cipher-builtin.c"
 158 #endif
 159
 160 QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
 161                                   QCryptoCipherMode mode,
 162                                   const uint8_t *key, size_t nkey,
 163                                   Error **errp)
 164 {
 165     QCryptoCipher *cipher;
 166     void *ctx = NULL;
 167     Error *err2 = NULL;
 168     QCryptoCipherDriver *drv = NULL;
 169
 170 #ifdef CONFIG_AF_ALG
 171     ctx = qcrypto_afalg_cipher_ctx_new(alg, mode, key, nkey, &err2);
 172     if (ctx) {
 173         drv = &qcrypto_cipher_afalg_driver;
 174     }
 175 #endif
 176
 177     if (!ctx) {
 178         ctx = qcrypto_cipher_ctx_new(alg, mode, key, nkey, errp);
 179         if (!ctx) {
 180             error_free(err2);
 181             return NULL;
 182         }
 183
 184         drv = &qcrypto_cipher_lib_driver;
 185         error_free(err2);
 186     }
 187
 188     cipher = g_new0(QCryptoCipher, 1);
 189     cipher->alg = alg;
 190     cipher->mode = mode;
 191     cipher->opaque = ctx;
 192     cipher->driver = (void *)drv;
 193
 194     return cipher;
 195 }
 196
 197
 198 int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
 199                            const void *in,
 200                            void *out,
 201                            size_t len,
 202                            Error **errp)
 203 {
 204     QCryptoCipherDriver *drv = cipher->driver;
 205     return drv->cipher_encrypt(cipher, in, out, len, errp);
 206 }
 207
 208
 209 int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
 210                            const void *in,
 211                            void *out,
 212                            size_t len,
 213                            Error **errp)
 214 {
 215     QCryptoCipherDriver *drv = cipher->driver;
 216     return drv->cipher_decrypt(cipher, in, out, len, errp);
 217 }
 218
 219
 220 int qcrypto_cipher_setiv(QCryptoCipher *cipher,
 221                          const uint8_t *iv, size_t niv,
 222                          Error **errp)
 223 {
 224     QCryptoCipherDriver *drv = cipher->driver;
 225     return drv->cipher_setiv(cipher, iv, niv, errp);
 226 }
 227
 228
 229 void qcrypto_cipher_free(QCryptoCipher *cipher)
 230 {
 231     QCryptoCipherDriver *drv;
 232     if (cipher) {
 233         drv = cipher->driver;
 234         drv->cipher_free(cipher);
 235         g_free(cipher);
 236     }
 237 }