- implementation supporting SHA1

- UNtested

2 files changed, 302 insertions, 0 deletions

diff --git a/Source/charon/transforms/hmac.c b/Source/charon/transforms/hmac.c
new file mode 100644
index 000000000..93bbffade
--- /dev/null
+++ b/Source/charon/transforms/hmac.c
@@ -0,0 +1,212 @@
+/**
+ * @file hmac.c
+ * 
+ * @brief Implementation of message authentication
+ * using cryptographic hash functions (HMAC). See RFC2104.
+ * 
+ */
+
+/*
+ * Copyright (C) 2005 Jan Hutter, Martin Willi
+ * 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 "hmac.h"
+
+#include "../utils/allocator.h"
+
+/**
+ * Private data of an hmac_t object.
+ * 
+ */
+typedef struct private_hmac_s private_hmac_t;
+
+struct private_hmac_s {
+	/**
+	 * public hmac_t interface
+	 */
+	hmac_t public;
+	
+	/**
+	 * key, as in RFC
+	 */
+	chunk_t k;
+	
+	/**
+	 * block size, as in RFC
+	 */
+	u_int8_t b;
+	
+	/**
+	 * hash function
+	 */
+	hasher_t *h;
+	
+	/**
+	 * previously xor'ed key using opad
+	 */
+	chunk_t opaded_key;
+	/**
+	 * previously xor'ed key using ipad
+	 */
+	chunk_t ipaded_key;
+};
+
+/**
+ * implementation of hmac_t.get_mac
+ */
+static status_t get_mac(private_hmac_t *this, chunk_t data, u_int8_t *out)
+{
+	/* H(K XOR opad, H(K XOR ipad, text)) */
+	u_int8_t buffer[this->h->get_block_size(this->h)];
+	chunk_t inner;
+	inner.ptr = buffer;
+	inner.len = this->h->get_block_size(this->h);
+	
+	/* inner */
+	this->h->get_hash(this->h, this->ipaded_key, NULL);
+	this->h->get_hash(this->h, data, buffer);
+	
+	/* outer */
+	this->h->get_hash(this->h, this->opaded_key, NULL);
+	this->h->get_hash(this->h, inner, out);
+	
+	return SUCCESS;
+}
+
+/**
+ * implementation of hmac_t.allocate_mac
+ */
+static status_t allocate_mac(private_hmac_t *this, chunk_t data, chunk_t *out)
+{
+	/* allocate space and use get_mac */
+	out->len = this->h->get_block_size(this->h);
+	out->ptr = allocator_alloc(out->len);
+	if (out->ptr == NULL)
+	{
+		return OUT_OF_RES;	
+	}
+	this->public.get_mac(&(this->public), data, out->ptr);
+	return SUCCESS;
+}
+	
+/**
+ * implementation of hmac_t.get_block_size
+ */
+static size_t get_block_size(private_hmac_t *this)
+{
+	return this->h->get_block_size(this->h);
+}
+
+/**
+ * implementation of hmac_t.destroy
+ */
+static status_t destroy(private_hmac_t *this)
+{
+	this->h->destroy(this->h);
+	allocator_free(this->k.ptr);
+	allocator_free(this->opaded_key.ptr);
+	allocator_free(this->ipaded_key.ptr);
+	allocator_free(this);
+	return SUCCESS;
+}
+
+/*
+ * Described in header
+ */
+hmac_t *hmac_create(hash_algorithm_t hash_algorithm, chunk_t key)
+{
+	private_hmac_t *this;
+	u_int8_t i;
+	
+	this = allocator_alloc_thing(private_hmac_t);
+	if (this == NULL)
+	{
+		return NULL;	
+	}
+	/* set public methods */
+	this->public.get_mac = (size_t (*)(hmac_t *,chunk_t,u_int8_t*))get_mac;
+	this->public.allocate_mac = (size_t (*)(hmac_t *,chunk_t,chunk_t*))allocate_mac;
+	this->public.get_block_size = (size_t (*)(hmac_t *))get_block_size;
+	this->public.destroy = (status_t (*)(hmac_t *))destroy;
+	
+	/* set b, according to hasher */
+	switch (hash_algorithm)
+	{
+		case HASH_SHA1:
+			this->b = 64;
+			break;
+		default:
+			allocator_free(this);
+			return NULL;	
+	}
+		
+	/* build the hasher */
+	this->h = hasher_create(hash_algorithm);
+	if (this->h == NULL)
+	{
+		allocator_free(this);
+		return NULL;	
+	}
+	
+	/* k must be b long, padded with 0x00 */
+	this->k.ptr = allocator_alloc(this->b);
+	this->k.len = this->b;
+	if (this->k.ptr == NULL)
+	{
+		this->h->destroy(this->h);
+		allocator_free(this);
+	}
+	memset(this->k.ptr, 0, this->k.len);
+
+	if (key.len > this->h->get_block_size(this->h))
+	{	
+		/* if key is too long, it will be hashed */
+		this->h->get_hash(this->h, key, this->k.ptr);
+	}
+	else
+	{	
+		/* if not, just copy it in our pre-padded k */
+		memcpy(this->k.ptr, key.ptr, key.len);	
+	}
+
+	/* build ipad and opad */
+	this->opaded_key.ptr = allocator_alloc(this->b);
+	this->opaded_key.len = this->b;
+	if (this->opaded_key.ptr == NULL)
+	{
+		this->h->destroy(this->h);
+		allocator_free(this->k.ptr);
+		allocator_free(this);
+		return NULL;	
+	}
+	this->ipaded_key.ptr = allocator_alloc(this->b);
+	this->ipaded_key.len = this->b;
+	if (this->ipaded_key.ptr == NULL)
+	{
+		this->h->destroy(this->h);
+		allocator_free(this->k.ptr);
+		allocator_free(this->opaded_key.ptr);
+		allocator_free(this);
+		return NULL;	
+	}
+		
+	for (i = 0; i < this->b; i++)
+	{
+		this->ipaded_key.ptr[i] = this->k.ptr[i] ^ 0x36;
+		this->opaded_key.ptr[i] = this->k.ptr[i] ^ 0x5C;
+	}
+	
+	return &(this->public);
+}
diff --git a/Source/charon/transforms/hmac.h b/Source/charon/transforms/hmac.h
new file mode 100644
index 000000000..f374b14f8
--- /dev/null
+++ b/Source/charon/transforms/hmac.h
@@ -0,0 +1,90 @@
+/**
+ * @file hmac.h
+ * 
+ * @brief Implementation of message authentication
+ * using cryptographic hash functions (HMAC). See RFC2104.
+ * 
+ */
+
+/*
+ * Copyright (C) 2005 Jan Hutter, Martin Willi
+ * 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.
+ */
+
+#ifndef HMAC_H_
+#define HMAC_H_
+
+
+#include "hashers/hasher.h"
+
+
+/**
+ * Object representing a hmac
+ */
+typedef struct hmac_s hmac_t;
+
+struct hmac_s {
+	/**
+	 * @brief Generate message authentication code.
+	 * 
+	 * @param this			calling hmac
+	 * @param data			chunk of data to authenticate
+	 * @param [out]buffer	pointer where the generated bytes will be written
+	 * @return				
+	 * 						- SUCCESS in any case
+	 */
+	status_t (*get_mac) (hmac_t *this, chunk_t data, u_int8_t *buffer);
+	
+	/**
+	 * @brief Generates message authentication code and 
+	 * allocate space for them.
+	 * 
+	 * @param this			calling hmac
+	 * @param data			chunk of data to authenticate
+	 * @param [out]chunk	chunk which will hold generated bytes
+	 * @return				
+	 * 						- SUCCESS in any case
+	 * 						- OUT_OF_RES if space could not be allocated
+	 */
+	status_t (*allocate_mac) (hmac_t *this, chunk_t data, chunk_t *chunk);
+	
+	/**
+	 * @brief get the block size of this hmac
+	 * 
+	 * @param this			calling hmac
+	 * @return				block size in bytes
+	 */
+	size_t (*get_block_size) (hmac_t *this);
+	
+	/**
+	 * @brief Destroys a hmac object.
+	 *
+	 * @param this 	hmac_t object to destroy
+	 * @return 		
+	 * 				SUCCESS in any case
+	 */
+	status_t (*destroy) (hmac_t *this);
+};
+
+/**
+ * Creates a new hmac_t object
+ * 
+ * @param hash_algorithm		hash algorithm to use
+ * @param key					A chunk containing the key
+ * @return
+ *								- hmac_t if successfully
+ *								- NULL if out of ressources or hash not supported
+ */
+hmac_t *hmac_create(hash_algorithm_t hash_algorithm, chunk_t key);
+
+#endif /*HMAC_H_*/