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/*
* Copyright (C) 2008 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.
*
* $Id$
*/
#include "openssl_hasher.h"
#include <openssl/evp.h>
typedef struct private_openssl_hasher_t private_openssl_hasher_t;
/**
* Private data of openssl_hasher_t
*/
struct private_openssl_hasher_t {
/**
* Public part of this class.
*/
openssl_hasher_t public;
/**
* data collected to hash
*/
chunk_t data;
/*
* the hasher to use
*/
const EVP_MD *hasher;
};
/**
* Mapping from the algorithms defined in IKEv2 to
* OpenSSL algorithm names
*/
typedef struct {
/**
* Identifier specified in IKEv2
*/
int ikev2_id;
/**
* Name of the algorithm, as used in OpenSSL
*/
char *name;
} openssl_algorithm_t;
#define END_OF_LIST -1
/**
* Algorithms for integrity
*/
static openssl_algorithm_t integrity_algs[] = {
{HASH_MD2, "md2"},
{HASH_MD5, "md5"},
{HASH_SHA1, "sha1"},
{HASH_SHA256, "sha256"},
{HASH_SHA384, "sha384"},
{HASH_SHA512, "sha512"},
{END_OF_LIST, NULL},
};
/**
* Look up an OpenSSL algorithm name
*/
static char* lookup_algorithm(openssl_algorithm_t *openssl_algo,
u_int16_t ikev2_algo)
{
while (openssl_algo->ikev2_id != END_OF_LIST)
{
if (ikev2_algo == openssl_algo->ikev2_id)
{
return openssl_algo->name;
}
openssl_algo++;
}
return NULL;
}
/**
* append data to the to-be-hashed buffer
*/
static void append_data(private_openssl_hasher_t *this, chunk_t data)
{
this->data.ptr = realloc(this->data.ptr, this->data.len + data.len);
memcpy(this->data.ptr + this->data.len, data.ptr, data.len);
this->data.len += data.len;
}
/**
* hash a buffer of data
*/
static void hash_data(private_openssl_hasher_t *this, chunk_t data, u_int8_t *digest)
{
EVP_MD_CTX ctx;
EVP_MD_CTX_init(&ctx);
EVP_DigestInit_ex(&ctx, this->hasher, NULL);
EVP_DigestUpdate(&ctx, data.ptr, data.len);
EVP_DigestFinal_ex(&ctx, digest, NULL);
EVP_MD_CTX_cleanup(&ctx);
}
/**
* Implementation of hasher_t.get_hash_size.
*/
static size_t get_hash_size(private_openssl_hasher_t *this)
{
return this->hasher->md_size;
}
/**
* Implementation of hasher_t.reset.
*/
static void reset(private_openssl_hasher_t *this)
{
chunk_free(&this->data);
}
/**
* Implementation of hasher_t.get_hash.
*/
static void get_hash(private_openssl_hasher_t *this, chunk_t chunk,
u_int8_t *hash)
{
if (hash)
{
if (this->data.len)
{
append_data(this, chunk);
hash_data(this, this->data, hash);
}
else
{ /* hash directly if no previous data found */
hash_data(this, chunk, hash);
}
reset(this);
}
else
{
append_data(this, chunk);
}
}
/**
* Implementation of hasher_t.allocate_hash.
*/
static void allocate_hash(private_openssl_hasher_t *this, chunk_t chunk,
chunk_t *hash)
{
if (hash)
{
*hash = chunk_alloc(get_hash_size(this));
get_hash(this, chunk, hash->ptr);
}
else
{
get_hash(this, chunk, NULL);
}
}
/**
* Implementation of hasher_t.destroy.
*/
static void destroy (private_openssl_hasher_t *this)
{
free(this->data.ptr);
free(this);
}
/*
* Described in header
*/
openssl_hasher_t *openssl_hasher_create(hash_algorithm_t algo)
{
private_openssl_hasher_t *this;
char* name = lookup_algorithm(integrity_algs, algo);
if (!name)
{
/* algo unavailable */
return NULL;
}
this = malloc_thing(private_openssl_hasher_t);
this->hasher = EVP_get_digestbyname(name);
if (!this->hasher)
{
/* OpenSSL does not support the requested algo */
free(this);
return NULL;
}
this->public.hasher_interface.get_hash = (void (*) (hasher_t*, chunk_t, u_int8_t*))get_hash;
this->public.hasher_interface.allocate_hash = (void (*) (hasher_t*, chunk_t, chunk_t*))allocate_hash;
this->public.hasher_interface.get_hash_size = (size_t (*) (hasher_t*))get_hash_size;
this->public.hasher_interface.reset = (void (*) (hasher_t*))reset;
this->public.hasher_interface.destroy = (void (*) (hasher_t*))destroy;
this->data = chunk_empty;
return &this->public;
}
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