qemu

cipher.h (7186B)

---

 /*
  * 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/>.
  *
  */
 
 #ifndef QCRYPTO_CIPHER_H
 #define QCRYPTO_CIPHER_H
 
 #include "qapi/qapi-types-crypto.h"
 
 typedef struct QCryptoCipher QCryptoCipher;
 typedef struct QCryptoCipherDriver QCryptoCipherDriver;
 
 /* See also "QCryptoCipherAlgorithm" and "QCryptoCipherMode"
  * enums defined in qapi/crypto.json */
 
 /**
  * QCryptoCipher:
  *
  * The QCryptoCipher object provides a way to perform encryption
  * and decryption of data, with a standard API, regardless of the
  * algorithm used. It further isolates the calling code from the
  * details of the specific underlying implementation, whether
  * built-in, libgcrypt or nettle.
  *
  * Each QCryptoCipher object is capable of performing both
  * encryption and decryption, and can operate in a number
  * or modes including ECB, CBC.
  *
  * <example>
  *   <title>Encrypting data with AES-128 in CBC mode</title>
  *   <programlisting>
  * QCryptoCipher *cipher;
  * uint8_t key = ....;
  * size_t keylen = 16;
  * uint8_t iv = ....;
  *
  * if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) {
  *    error_report(errp, "Feature <blah> requires AES cipher support");
  *    return -1;
  * }
  *
  * cipher = qcrypto_cipher_new(QCRYPTO_CIPHER_ALG_AES_128,
  *                             QCRYPTO_CIPHER_MODE_CBC,
  *                             key, keylen,
  *                             errp);
  * if (!cipher) {
  *    return -1;
  * }
  *
  * if (qcrypto_cipher_set_iv(cipher, iv, keylen, errp) < 0) {
  *    return -1;
  * }
  *
  * if (qcrypto_cipher_encrypt(cipher, rawdata, encdata, datalen, errp) < 0) {
  *    return -1;
  * }
  *
  * qcrypto_cipher_free(cipher);
  *   </programlisting>
  * </example>
  *
  */
 
 struct QCryptoCipher {
     QCryptoCipherAlgorithm alg;
     QCryptoCipherMode mode;
     const QCryptoCipherDriver *driver;
 };
 
 /**
  * qcrypto_cipher_supports:
  * @alg: the cipher algorithm
  * @mode: the cipher mode
  *
  * Determine if @alg cipher algorithm in @mode is supported by the
  * current configured build
  *
  * Returns: true if the algorithm is supported, false otherwise
  */
 bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg,
                              QCryptoCipherMode mode);
 
 /**
  * qcrypto_cipher_get_block_len:
  * @alg: the cipher algorithm
  *
  * Get the required data block size in bytes. When
  * encrypting data, it must be a multiple of the
  * block size.
  *
  * Returns: the block size in bytes
  */
 size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg);
 
 
 /**
  * qcrypto_cipher_get_key_len:
  * @alg: the cipher algorithm
  *
  * Get the required key size in bytes.
  *
  * Returns: the key size in bytes
  */
 size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg);
 
 
 /**
  * qcrypto_cipher_get_iv_len:
  * @alg: the cipher algorithm
  * @mode: the cipher mode
  *
  * Get the required initialization vector size
  * in bytes, if one is required.
  *
  * Returns: the IV size in bytes, or 0 if no IV is permitted
  */
 size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg,
                                  QCryptoCipherMode mode);
 
 
 /**
  * qcrypto_cipher_new:
  * @alg: the cipher algorithm
  * @mode: the cipher usage mode
  * @key: the private key bytes
  * @nkey: the length of @key
  * @errp: pointer to a NULL-initialized error object
  *
  * Creates a new cipher object for encrypting/decrypting
  * data with the algorithm @alg in the usage mode @mode.
  *
  * The @key parameter provides the bytes representing
  * the encryption/decryption key to use. The @nkey parameter
  * specifies the length of @key in bytes. Each algorithm has
  * one or more valid key lengths, and it is an error to provide
  * a key of the incorrect length.
  *
  * The returned cipher object must be released with
  * qcrypto_cipher_free() when no longer required
  *
  * Returns: a new cipher object, or NULL on error
  */
 QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
                                   QCryptoCipherMode mode,
                                   const uint8_t *key, size_t nkey,
                                   Error **errp);
 
 /**
  * qcrypto_cipher_free:
  * @cipher: the cipher object
  *
  * Release the memory associated with @cipher that
  * was previously allocated by qcrypto_cipher_new()
  */
 void qcrypto_cipher_free(QCryptoCipher *cipher);
 
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(QCryptoCipher, qcrypto_cipher_free)
 
 /**
  * qcrypto_cipher_encrypt:
  * @cipher: the cipher object
  * @in: buffer holding the plain text input data
  * @out: buffer to fill with the cipher text output data
  * @len: the length of @in and @out buffers
  * @errp: pointer to a NULL-initialized error object
  *
  * Encrypts the plain text stored in @in, filling
  * @out with the resulting ciphered text. Both the
  * @in and @out buffers must have the same size,
  * given by @len.
  *
  * Returns: 0 on success, or -1 on error
  */
 int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
                            const void *in,
                            void *out,
                            size_t len,
                            Error **errp);
 
 
 /**
  * qcrypto_cipher_decrypt:
  * @cipher: the cipher object
  * @in: buffer holding the cipher text input data
  * @out: buffer to fill with the plain text output data
  * @len: the length of @in and @out buffers
  * @errp: pointer to a NULL-initialized error object
  *
  * Decrypts the cipher text stored in @in, filling
  * @out with the resulting plain text. Both the
  * @in and @out buffers must have the same size,
  * given by @len.
  *
  * Returns: 0 on success, or -1 on error
  */
 int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
                            const void *in,
                            void *out,
                            size_t len,
                            Error **errp);
 
 /**
  * qcrypto_cipher_setiv:
  * @cipher: the cipher object
  * @iv: the initialization vector or counter (CTR mode) bytes
  * @niv: the length of @iv
  * @errpr: pointer to a NULL-initialized error object
  *
  * If the @cipher object is setup to use a mode that requires
  * initialization vectors or counter, this sets the @niv
  * bytes. The @iv data should have the same length as the
  * cipher key used when originally constructing the cipher
  * object. It is an error to set an initialization vector
  * or counter if the cipher mode does not require one.
  *
  * Returns: 0 on success, -1 on error
  */
 int qcrypto_cipher_setiv(QCryptoCipher *cipher,
                          const uint8_t *iv, size_t niv,
                          Error **errp);
 
 #endif /* QCRYPTO_CIPHER_H */