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Strongswan

    1: /*
    2:  * Copyright (C) 2012 Tobias Brunner
    3:  * Copyright (C) 2005-2008 Martin Willi
    4:  * Copyright (C) 2005 Jan Hutter
    5:  * HSR Hochschule fuer Technik Rapperswil
    6:  *
    7:  * This program is free software; you can redistribute it and/or modify it
    8:  * under the terms of the GNU General Public License as published by the
    9:  * Free Software Foundation; either version 2 of the License, or (at your
   10:  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
   11:  *
   12:  * This program is distributed in the hope that it will be useful, but
   13:  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   14:  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   15:  * for more details.
   16:  */
   17: 
   18: #include "mac_signer.h"
   19: 
   20: typedef struct private_signer_t private_signer_t;
   21: 
   22: /**
   23:  * Private data of a mac_signer_t object.
   24:  */
   25: struct private_signer_t {
   26: 
   27: 	/**
   28: 	 * Public interface
   29: 	 */
   30: 	signer_t public;
   31: 
   32: 	/**
   33: 	 * MAC to use
   34: 	 */
   35: 	mac_t *mac;
   36: 
   37: 	/**
   38: 	 * Truncation of MAC output
   39: 	 */
   40: 	size_t truncation;
   41: };
   42: 
   43: METHOD(signer_t, get_signature, bool,
   44: 	private_signer_t *this, chunk_t data, uint8_t *buffer)
   45: {
   46: 	if (buffer)
   47: 	{
   48: 		uint8_t mac[this->mac->get_mac_size(this->mac)];
   49: 
   50: 		if (!this->mac->get_mac(this->mac, data, mac))
   51: 		{
   52: 			return FALSE;
   53: 		}
   54: 		memcpy(buffer, mac, this->truncation);
   55: 		return TRUE;
   56: 	}
   57: 	return this->mac->get_mac(this->mac, data, NULL);
   58: }
   59: 
   60: METHOD(signer_t, allocate_signature, bool,
   61: 	private_signer_t *this, chunk_t data, chunk_t *chunk)
   62: {
   63: 	if (chunk)
   64: 	{
   65: 		uint8_t mac[this->mac->get_mac_size(this->mac)];
   66: 
   67: 		if (!this->mac->get_mac(this->mac, data, mac))
   68: 		{
   69: 			return FALSE;
   70: 		}
   71: 		*chunk = chunk_alloc(this->truncation);
   72: 		memcpy(chunk->ptr, mac, this->truncation);
   73: 		return TRUE;
   74: 	}
   75: 	return this->mac->get_mac(this->mac, data, NULL);
   76: }
   77: 
   78: METHOD(signer_t, verify_signature, bool,
   79: 	private_signer_t *this, chunk_t data, chunk_t signature)
   80: {
   81: 	uint8_t mac[this->mac->get_mac_size(this->mac)];
   82: 
   83: 	if (signature.len != this->truncation)
   84: 	{
   85: 		return FALSE;
   86: 	}
   87: 	return this->mac->get_mac(this->mac, data, mac) &&
   88: 		   memeq_const(signature.ptr, mac, this->truncation);
   89: }
   90: 
   91: METHOD(signer_t, get_key_size, size_t,
   92: 	private_signer_t *this)
   93: {
   94: 	return this->mac->get_mac_size(this->mac);
   95: }
   96: 
   97: METHOD(signer_t, get_block_size, size_t,
   98: 	private_signer_t *this)
   99: {
  100: 	return this->truncation;
  101: }
  102: 
  103: METHOD(signer_t, set_key, bool,
  104: 	private_signer_t *this, chunk_t key)
  105: {
  106: 	return this->mac->set_key(this->mac, key);
  107: }
  108: 
  109: METHOD(signer_t, destroy, void,
  110: 	private_signer_t *this)
  111: {
  112: 	this->mac->destroy(this->mac);
  113: 	free(this);
  114: }
  115: 
  116: /*
  117:  * Described in header
  118:  */
  119: signer_t *mac_signer_create(mac_t *mac, size_t len)
  120: {
  121: 	private_signer_t *this;
  122: 
  123: 	INIT(this,
  124: 		.public = {
  125: 			.get_signature = _get_signature,
  126: 			.allocate_signature = _allocate_signature,
  127: 			.verify_signature = _verify_signature,
  128: 			.get_block_size = _get_block_size,
  129: 			.get_key_size = _get_key_size,
  130: 			.set_key = _set_key,
  131: 			.destroy = _destroy,
  132: 		},
  133: 		.truncation = min(len, mac->get_mac_size(mac)),
  134: 		.mac = mac,
  135: 	);
  136: 
  137: 	return &this->public;
  138: }