Make the hmac_t interface a generic interface for message authentication codes

src/libstrongswan/crypto/signers/mac_signer.c

@@ -0,0 +1,138 @@
+/*
+ * Copyright (C) 2012 Tobias Brunner
+ * Copyright (C) 2005-2008 Martin Willi
+ * Copyright (C) 2005 Jan Hutter
+ * 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.
+ */
+
+#include "mac_signer.h"
+
+typedef struct private_signer_t private_signer_t;
+
+/**
+ * Private data of a mac_signer_t object.
+ */
+struct private_signer_t {
+
+	/**
+	 * Public interface
+	 */
+	signer_t public;
+
+	/**
+	 * MAC to use
+	 */
+	mac_t *mac;
+
+	/**
+	 * Truncation of MAC output
+	 */
+	size_t truncation;
+};
+
+METHOD(signer_t, get_signature, void,
+	private_signer_t *this, chunk_t data, u_int8_t *buffer)
+{
+	if (buffer == NULL)
+	{
+		this->mac->get_mac(this->mac, data, NULL);
+	}
+	else
+	{
+		u_int8_t mac[this->mac->get_mac_size(this->mac)];
+
+		this->mac->get_mac(this->mac, data, mac);
+		memcpy(buffer, mac, this->truncation);
+	}
+}
+
+METHOD(signer_t, allocate_signature, void,
+	private_signer_t *this, chunk_t data, chunk_t *chunk)
+{
+	if (chunk == NULL)
+	{
+		this->mac->get_mac(this->mac, data, NULL);
+	}
+	else
+	{
+		u_int8_t mac[this->mac->get_mac_size(this->mac)];
+
+		this->mac->get_mac(this->mac, data, mac);
+
+		*chunk = chunk_alloc(this->truncation);
+		memcpy(chunk->ptr, mac, this->truncation);
+	}
+}
+
+METHOD(signer_t, verify_signature, bool,
+	private_signer_t *this, chunk_t data, chunk_t signature)
+{
+	u_int8_t mac[this->mac->get_mac_size(this->mac)];
+
+	if (signature.len != this->truncation)
+	{
+		return FALSE;
+	}
+	this->mac->get_mac(this->mac, data, mac);
+	return memeq(signature.ptr, mac, this->truncation);
+}
+
+METHOD(signer_t, get_key_size, size_t,
+	private_signer_t *this)
+{
+	return this->mac->get_mac_size(this->mac);
+}
+
+METHOD(signer_t, get_block_size, size_t,
+	private_signer_t *this)
+{
+	return this->truncation;
+}
+
+METHOD(signer_t, set_key, void,
+	private_signer_t *this, chunk_t key)
+{
+	this->mac->set_key(this->mac, key);
+}
+
+METHOD(signer_t, destroy, void,
+	private_signer_t *this)
+{
+	this->mac->destroy(this->mac);
+	free(this);
+}
+
+/*
+ * Described in header
+ */
+signer_t *mac_signer_create(mac_t *mac, size_t len)
+{
+	private_signer_t *this;
+
+	INIT(this,
+		.public = {
+			.get_signature = _get_signature,
+			.allocate_signature = _allocate_signature,
+			.verify_signature = _verify_signature,
+			.get_block_size = _get_block_size,
+			.get_key_size = _get_key_size,
+			.set_key = _set_key,
+			.destroy = _destroy,
+		},
+		.truncation = min(len, mac->get_mac_size(mac)),
+		.mac = mac,
+	);
+
+	return &this->public;
+}
+

src/libstrongswan/crypto/signers/mac_signer.h

@@ -0,0 +1,41 @@
+/*
+ * 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.
+ */
+
+/**
+ * @defgroup mac_signer mac_signer
+ * @{ @ingroup crypto
+ */
+
+#ifndef MAC_SIGNER_H_
+#define MAC_SIGNER_H_
+
+typedef struct mac_signer_t mac_signer_t;
+
+#include <crypto/mac.h>
+#include <crypto/signers/signer.h>
+
+/**
+ * Creates an implementation of the signer_t interface using the provided mac_t
+ * implementation and truncation length.
+ *
+ * @note len will be set to mac_t.get_mac_size() if it is greater than that.
+ *
+ * @param mac		mac_t implementation
+ * @param len		length of resulting signature
+ * @return			mac_signer_t
+ */
+signer_t *mac_signer_create(mac_t *mac, size_t len);
+
+#endif /** MAC_SIGNER_H_ @}*/