qemu

cipher.c (5915B)

---

 /*
  * QEMU Crypto cipher algorithms
  *
  * Copyright (c) 2015 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  *
  */
 
 #include "qemu/osdep.h"
 #include "qemu/host-utils.h"
 #include "qapi/error.h"
 #include "crypto/cipher.h"
 #include "cipherpriv.h"
 
 
 static const size_t alg_key_len[QCRYPTO_CIPHER_ALG__MAX] = {
     [QCRYPTO_CIPHER_ALG_AES_128] = 16,
     [QCRYPTO_CIPHER_ALG_AES_192] = 24,
     [QCRYPTO_CIPHER_ALG_AES_256] = 32,
     [QCRYPTO_CIPHER_ALG_DES] = 8,
     [QCRYPTO_CIPHER_ALG_3DES] = 24,
     [QCRYPTO_CIPHER_ALG_CAST5_128] = 16,
     [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
     [QCRYPTO_CIPHER_ALG_SERPENT_192] = 24,
     [QCRYPTO_CIPHER_ALG_SERPENT_256] = 32,
     [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
     [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 24,
     [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 32,
 };
 
 static const size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
     [QCRYPTO_CIPHER_ALG_AES_128] = 16,
     [QCRYPTO_CIPHER_ALG_AES_192] = 16,
     [QCRYPTO_CIPHER_ALG_AES_256] = 16,
     [QCRYPTO_CIPHER_ALG_DES] = 8,
     [QCRYPTO_CIPHER_ALG_3DES] = 8,
     [QCRYPTO_CIPHER_ALG_CAST5_128] = 8,
     [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
     [QCRYPTO_CIPHER_ALG_SERPENT_192] = 16,
     [QCRYPTO_CIPHER_ALG_SERPENT_256] = 16,
     [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
     [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 16,
     [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 16,
 };
 
 static const bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = {
     [QCRYPTO_CIPHER_MODE_ECB] = false,
     [QCRYPTO_CIPHER_MODE_CBC] = true,
     [QCRYPTO_CIPHER_MODE_XTS] = true,
     [QCRYPTO_CIPHER_MODE_CTR] = true,
 };
 
 
 size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg)
 {
     assert(alg < G_N_ELEMENTS(alg_key_len));
     return alg_block_len[alg];
 }
 
 
 size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg)
 {
     assert(alg < G_N_ELEMENTS(alg_key_len));
     return alg_key_len[alg];
 }
 
 
 size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg,
                                  QCryptoCipherMode mode)
 {
     if (alg >= G_N_ELEMENTS(alg_block_len)) {
         return 0;
     }
     if (mode >= G_N_ELEMENTS(mode_need_iv)) {
         return 0;
     }
 
     if (mode_need_iv[mode]) {
         return alg_block_len[alg];
     }
     return 0;
 }
 
 
 static bool
 qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg,
                                    QCryptoCipherMode mode,
                                    size_t nkey,
                                    Error **errp)
 {
     if ((unsigned)alg >= QCRYPTO_CIPHER_ALG__MAX) {
         error_setg(errp, "Cipher algorithm %d out of range",
                    alg);
         return false;
     }
 
     if (mode == QCRYPTO_CIPHER_MODE_XTS) {
         if (alg == QCRYPTO_CIPHER_ALG_DES ||
             alg == QCRYPTO_CIPHER_ALG_3DES) {
             error_setg(errp, "XTS mode not compatible with DES/3DES");
             return false;
         }
         if (nkey % 2) {
             error_setg(errp, "XTS cipher key length should be a multiple of 2");
             return false;
         }
 
         if (alg_key_len[alg] != (nkey / 2)) {
             error_setg(errp, "Cipher key length %zu should be %zu",
                        nkey, alg_key_len[alg] * 2);
             return false;
         }
     } else {
         if (alg_key_len[alg] != nkey) {
             error_setg(errp, "Cipher key length %zu should be %zu",
                        nkey, alg_key_len[alg]);
             return false;
         }
     }
     return true;
 }
 
 #ifdef CONFIG_GCRYPT
 #include "cipher-gcrypt.c.inc"
 #elif defined CONFIG_NETTLE
 #include "cipher-nettle.c.inc"
 #elif defined CONFIG_GNUTLS_CRYPTO
 #include "cipher-gnutls.c.inc"
 #else
 #include "cipher-builtin.c.inc"
 #endif
 
 QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
                                   QCryptoCipherMode mode,
                                   const uint8_t *key, size_t nkey,
                                   Error **errp)
 {
     QCryptoCipher *cipher = NULL;
 
 #ifdef CONFIG_AF_ALG
     cipher = qcrypto_afalg_cipher_ctx_new(alg, mode, key, nkey, NULL);
 #endif
 
     if (!cipher) {
         cipher = qcrypto_cipher_ctx_new(alg, mode, key, nkey, errp);
         if (!cipher) {
             return NULL;
         }
     }
 
     cipher->alg = alg;
     cipher->mode = mode;
 
     return cipher;
 }
 
 
 int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
                            const void *in,
                            void *out,
                            size_t len,
                            Error **errp)
 {
     const QCryptoCipherDriver *drv = cipher->driver;
     return drv->cipher_encrypt(cipher, in, out, len, errp);
 }
 
 
 int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
                            const void *in,
                            void *out,
                            size_t len,
                            Error **errp)
 {
     const QCryptoCipherDriver *drv = cipher->driver;
     return drv->cipher_decrypt(cipher, in, out, len, errp);
 }
 
 
 int qcrypto_cipher_setiv(QCryptoCipher *cipher,
                          const uint8_t *iv, size_t niv,
                          Error **errp)
 {
     const QCryptoCipherDriver *drv = cipher->driver;
     return drv->cipher_setiv(cipher, iv, niv, errp);
 }
 
 
 void qcrypto_cipher_free(QCryptoCipher *cipher)
 {
     if (cipher) {
         cipher->driver->cipher_free(cipher);
     }
 }