1 files changed, 174 insertions, 0 deletions
diff --git a/src/libstrongswan/crypto/signers/hmac_signer.c b/src/libstrongswan/crypto/signers/hmac_signer.c
new file mode 100644
index 000000000..76e1ce50e
--- /dev/null
+++ b/src/libstrongswan/crypto/signers/hmac_signer.c
@@ -0,0 +1,174 @@
+/**
+ * @file hmac_signer.c
+ * 
+ * @brief Implementation of hmac_signer_t.
+ * 
+ */
+
+/*
+ * Copyright (C) 2005-2006 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 <string.h>
+
+#include "hmac_signer.h"
+
+#include <crypto/prfs/hmac_prf.h>
+
+typedef struct private_hmac_signer_t private_hmac_signer_t;
+
+/**
+ * Private data structure with signing context.
+ */
+struct private_hmac_signer_t {
+	/**
+	 * Public interface of hmac_signer_t.
+	 */
+	hmac_signer_t public;
+	
+	/**
+	 * Assigned hmac function.
+	 */
+	prf_t *hmac_prf;
+	
+	/**
+	 * Block size (truncation of HMAC Hash)
+	 */
+	size_t block_size;
+};
+
+/**
+ * Implementation of signer_t.get_signature.
+ */
+static void get_signature (private_hmac_signer_t *this, chunk_t data, u_int8_t *buffer)
+{
+	u_int8_t full_mac[this->hmac_prf->get_block_size(this->hmac_prf)];
+	
+	this->hmac_prf->get_bytes(this->hmac_prf, data, full_mac);
+
+	/* copy MAC depending on truncation */
+	memcpy(buffer, full_mac, this->block_size);
+}
+
+/**
+ * Implementation of signer_t.allocate_signature.
+ */
+static void allocate_signature (private_hmac_signer_t *this, chunk_t data, chunk_t *chunk)
+{
+	chunk_t signature;
+	u_int8_t full_mac[this->hmac_prf->get_block_size(this->hmac_prf)];
+	
+	this->hmac_prf->get_bytes(this->hmac_prf,data,full_mac);
+
+	signature.ptr = malloc(this->block_size);
+	signature.len = this->block_size;
+	
+	/* copy signature */
+	memcpy(signature.ptr, full_mac, this->block_size);
+
+	*chunk = signature;
+}
+
+/**
+ * Implementation of signer_t.verify_signature.
+ */
+static bool verify_signature(private_hmac_signer_t *this, chunk_t data, chunk_t signature)
+{
+	u_int8_t full_mac[this->hmac_prf->get_block_size(this->hmac_prf)];
+	
+	this->hmac_prf->get_bytes(this->hmac_prf, data, full_mac);
+	
+	if (signature.len != this->block_size)
+	{
+		return FALSE;
+	}
+	
+	/* compare mac aka signature :-) */
+	if (memcmp(signature.ptr, full_mac, this->block_size) == 0)
+	{
+		return TRUE;
+	}
+	else
+	{
+		return FALSE;
+	}
+}
+
+/**
+ * Implementation of signer_t.get_key_size.
+ */
+static size_t get_key_size(private_hmac_signer_t *this)
+{
+	/* for HMAC signer, IKEv2 uses block size as key size */
+	return this->hmac_prf->get_block_size(this->hmac_prf);
+}
+
+/**
+ * Implementation of signer_t.get_block_size.
+ */
+static size_t get_block_size(private_hmac_signer_t *this)
+{
+	return this->block_size;
+}
+
+/**
+ * Implementation of signer_t.set_key.
+ */
+static void set_key(private_hmac_signer_t *this, chunk_t key)
+{
+	this->hmac_prf->set_key(this->hmac_prf, key);
+}
+
+/**
+ * Implementation of signer_t.destroy.
+ */
+static status_t destroy(private_hmac_signer_t *this)
+{
+	this->hmac_prf->destroy(this->hmac_prf);
+	free(this);
+	return SUCCESS;
+}
+
+/*
+ * Described in header
+ */
+hmac_signer_t *hmac_signer_create(hash_algorithm_t hash_algoritm, size_t block_size)
+{
+	size_t hmac_block_size;
+	private_hmac_signer_t *this = malloc_thing(private_hmac_signer_t);
+
+	this->hmac_prf = (prf_t *) hmac_prf_create(hash_algoritm);
+	if (this->hmac_prf == NULL)
+	{
+		/* algorithm not supported */
+		free(this);
+		return NULL;
+	}
+	
+	/* prevent invalid truncation */
+	hmac_block_size = this->hmac_prf->get_block_size(this->hmac_prf);
+	this->block_size = min(block_size, hmac_block_size);
+	
+	/* interface functions */
+	this->public.signer_interface.get_signature = (void (*) (signer_t*, chunk_t, u_int8_t*))get_signature;
+	this->public.signer_interface.allocate_signature = (void (*) (signer_t*, chunk_t, chunk_t*))allocate_signature;
+	this->public.signer_interface.verify_signature = (bool (*) (signer_t*, chunk_t, chunk_t))verify_signature;
+	this->public.signer_interface.get_key_size = (size_t (*) (signer_t*))get_key_size;
+	this->public.signer_interface.get_block_size = (size_t (*) (signer_t*))get_block_size;
+	this->public.signer_interface.set_key = (void (*) (signer_t*,chunk_t))set_key;
+	this->public.signer_interface.destroy = (void (*) (signer_t*))destroy;
+	
+	return &(this->public);
+}