Refactored OpenSSL based HMAC implementation

2012-06-25 16:35:06 +02:00
parent 54081897cf
commit 8391c1d0b1
5 changed files with 405 additions and 196 deletions
@@ -0,0 +1,177 @@
+/*
+ * Copyright (C) 2012 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program 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 General Public License
+ * for more details.
+ */
+
+/*
+ * Copyright (C) 2012 Aleksandr Grinberg
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <openssl/evp.h>
+#include <openssl/hmac.h>
+
+#include "openssl_hmac.h"
+
+typedef struct private_openssl_hmac_t private_openssl_hmac_t;
+
+/**
+ * Private data of a openssl_hmac_t object.
+ */
+struct private_openssl_hmac_t {
+
+	/**
+	 * Public interface
+	 */
+	openssl_hmac_t public;
+
+	/**
+	 * Hasher to use
+	 */
+	const EVP_MD *hasher;
+
+	/**
+	 * Current HMAC context
+	 */
+	HMAC_CTX hmac;
+
+	/**
+	 * Key
+	 */
+	chunk_t key;
+};
+
+/**
+ * Resets HMAC context
+ */
+static void reset(private_openssl_hmac_t *this)
+{
+	HMAC_Init_ex(&this->hmac, this->key.ptr, this->key.len, this->hasher, NULL);
+}
+
+METHOD(openssl_hmac_t, get_mac, void,
+	private_openssl_hmac_t *this, chunk_t data, u_int8_t *out)
+{
+	if (out == NULL)
+	{
+		HMAC_Update(&this->hmac, data.ptr, data.len);
+	}
+	else
+	{
+		HMAC_Update(&this->hmac, data.ptr, data.len);
+		HMAC_Final(&this->hmac, out, NULL);
+		reset(this);
+	}
+}
+
+METHOD(openssl_hmac_t, allocate_mac, void,
+	private_openssl_hmac_t *this, chunk_t data, chunk_t *out)
+{
+	if (out == NULL)
+	{
+		get_mac(this, data, NULL);
+	}
+	else
+	{
+		*out = chunk_alloc(EVP_MD_size(this->hasher));
+		get_mac(this, data, out->ptr);
+	}
+}
+
+METHOD(openssl_hmac_t, get_block_size, size_t,
+	private_openssl_hmac_t *this)
+{
+	return EVP_MD_size(this->hasher);
+}
+
+METHOD(openssl_hmac_t, set_key, void,
+	private_openssl_hmac_t *this, chunk_t key)
+{
+	chunk_clear(&this->key);
+	this->key = chunk_clone(key);
+	reset(this);
+}
+
+METHOD(openssl_hmac_t, destroy, void,
+	private_openssl_hmac_t *this)
+{
+	HMAC_CTX_cleanup(&this->hmac);
+	chunk_clear(&this->key);
+	free(this);
+}
+
+/*
+ * Described in header
+ */
+openssl_hmac_t *openssl_hmac_create(hash_algorithm_t algo)
+{
+	private_openssl_hmac_t *this;
+
+	INIT(this,
+		.public = {
+			.get_mac = _get_mac,
+			.allocate_mac = _allocate_mac,
+			.get_block_size = _get_block_size,
+			.set_key = _set_key,
+			.destroy = _destroy,
+		},
+	);
+
+	switch (algo)
+	{
+		case HASH_MD5:
+			this->hasher = EVP_get_digestbyname("md5");
+			break;
+		case HASH_SHA1:
+			this->hasher = EVP_get_digestbyname("sha1");
+			break;
+		case HASH_SHA256:
+			this->hasher = EVP_get_digestbyname("sha256");
+			break;
+		case HASH_SHA384:
+			this->hasher = EVP_get_digestbyname("sha384");
+			break;
+		case HASH_SHA512:
+			this->hasher = EVP_get_digestbyname("sha512");
+			break;
+		default:
+			break;
+	}
+
+	if (!this->hasher)
+	{
+		free(this);
+		return NULL;
+	}
+
+	HMAC_CTX_init(&this->hmac);
+
+	return &this->public;
+}