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/*
* Copyright (C) 2014 Martin Willi
* Copyright (C) 2014 revosec AG
*
* 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 "tls_aead.h"
typedef struct private_tls_aead_t private_tls_aead_t;
/**
* Private data of an tls_aead_t object.
*/
struct private_tls_aead_t {
/**
* Public tls_aead_t interface.
*/
tls_aead_t public;
/**
* traditional signer
*/
signer_t *signer;
};
/**
* Associated header data to create signature over
*/
typedef struct __attribute__((__packed__)) {
uint64_t seq;
uint8_t type;
uint16_t version;
uint16_t length;
} sigheader_t;
METHOD(tls_aead_t, encrypt, bool,
private_tls_aead_t *this, tls_version_t version,
tls_content_type_t type, uint64_t seq, chunk_t *data)
{
chunk_t assoc, mac;
sigheader_t hdr;
hdr.type = type;
htoun64(&hdr.seq, seq);
htoun16(&hdr.version, version);
htoun16(&hdr.length, data->len);
assoc = chunk_from_thing(hdr);
if (!this->signer->get_signature(this->signer, assoc, NULL) ||
!this->signer->allocate_signature(this->signer, *data, &mac))
{
return FALSE;
}
*data = chunk_cat("mm", *data, mac);
return TRUE;
}
METHOD(tls_aead_t, decrypt, bool,
private_tls_aead_t *this, tls_version_t version,
tls_content_type_t type, uint64_t seq, chunk_t *data)
{
chunk_t assoc, mac;
sigheader_t hdr;
mac.len = this->signer->get_block_size(this->signer);
if (data->len < mac.len)
{
return FALSE;
}
mac = chunk_skip(*data, data->len - mac.len);
data->len -= mac.len;
hdr.type = type;
htoun64(&hdr.seq, seq);
htoun16(&hdr.version, version);
htoun16(&hdr.length, data->len);
assoc = chunk_from_thing(hdr);
if (!this->signer->get_signature(this->signer, assoc, NULL) ||
!this->signer->verify_signature(this->signer, *data, mac))
{
return FALSE;
}
return TRUE;
}
METHOD(tls_aead_t, get_mac_key_size, size_t,
private_tls_aead_t *this)
{
return this->signer->get_key_size(this->signer);
}
METHOD(tls_aead_t, get_encr_key_size, size_t,
private_tls_aead_t *this)
{
return 0;
}
METHOD(tls_aead_t, get_iv_size, size_t,
private_tls_aead_t *this)
{
return 0;
}
METHOD(tls_aead_t, set_keys, bool,
private_tls_aead_t *this, chunk_t mac, chunk_t encr, chunk_t iv)
{
if (iv.len || encr.len)
{
return FALSE;
}
return this->signer->set_key(this->signer, mac);
}
METHOD(tls_aead_t, destroy, void,
private_tls_aead_t *this)
{
this->signer->destroy(this->signer);
free(this);
}
/**
* See header
*/
tls_aead_t *tls_aead_create_null(integrity_algorithm_t alg)
{
private_tls_aead_t *this;
INIT(this,
.public = {
.encrypt = _encrypt,
.decrypt = _decrypt,
.get_mac_key_size = _get_mac_key_size,
.get_encr_key_size = _get_encr_key_size,
.get_iv_size = _get_iv_size,
.set_keys = _set_keys,
.destroy = _destroy,
},
.signer = lib->crypto->create_signer(lib->crypto, alg),
);
if (!this->signer)
{
free(this);
return NULL;
}
return &this->public;
}
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