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/*
* 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, bool,
private_signer_t *this, chunk_t data, uint8_t *buffer)
{
if (buffer)
{
uint8_t mac[this->mac->get_mac_size(this->mac)];
if (!this->mac->get_mac(this->mac, data, mac))
{
return FALSE;
}
memcpy(buffer, mac, this->truncation);
return TRUE;
}
return this->mac->get_mac(this->mac, data, NULL);
}
METHOD(signer_t, allocate_signature, bool,
private_signer_t *this, chunk_t data, chunk_t *chunk)
{
if (chunk)
{
uint8_t mac[this->mac->get_mac_size(this->mac)];
if (!this->mac->get_mac(this->mac, data, mac))
{
return FALSE;
}
*chunk = chunk_alloc(this->truncation);
memcpy(chunk->ptr, mac, this->truncation);
return TRUE;
}
return this->mac->get_mac(this->mac, data, NULL);
}
METHOD(signer_t, verify_signature, bool,
private_signer_t *this, chunk_t data, chunk_t signature)
{
uint8_t mac[this->mac->get_mac_size(this->mac)];
if (signature.len != this->truncation)
{
return FALSE;
}
return this->mac->get_mac(this->mac, data, mac) &&
memeq_const(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, bool,
private_signer_t *this, chunk_t key)
{
return 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;
}
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