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Diffstat (limited to 'include/crypto/cipher.h')
-rw-r--r-- | include/crypto/cipher.h | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/include/crypto/cipher.h b/include/crypto/cipher.h new file mode 100644 index 0000000000..b4d714f269 --- /dev/null +++ b/include/crypto/cipher.h @@ -0,0 +1,210 @@ +/* + * 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 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 "qemu-common.h" +#include "qapi/error.h" + +typedef struct QCryptoCipher QCryptoCipher; + +typedef enum { + QCRYPTO_CIPHER_ALG_AES_128, + QCRYPTO_CIPHER_ALG_AES_192, + QCRYPTO_CIPHER_ALG_AES_256, + QCRYPTO_CIPHER_ALG_DES_RFB, /* A stupid variant on DES for VNC */ + + QCRYPTO_CIPHER_ALG_LAST +} QCryptoCipherAlgorithm; + +typedef enum { + QCRYPTO_CIPHER_MODE_ECB, + QCRYPTO_CIPHER_MODE_CBC, + + QCRYPTO_CIPHER_MODE_LAST +} QCryptoCipherMode; + +/** + * 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; + void *opaque; +}; + +/** + * qcrypto_cipher_supports: + * @alg: the cipher algorithm + * + * Determine if @alg cipher algorithm is supported by the + * current configured build + * + * Returns: true if the algorithm is supported, false otherwise + */ +bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg); + + +/** + * 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 an uninitialized 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); + +/** + * 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 an uninitialized 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 an uninitialized 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 bytes + * @niv: the length of @iv + * @errpr: pointer to an uninitialized error object + * + * If the @cipher object is setup to use a mode that requires + * initialization vectors, this sets the initialization vector + * 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 + * 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__ */ |