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/*
* Copyright (C) 2010 Martin Willi
* Copyright (C) 2010 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 "hook.h"
#include <time.h>
#include <netinet/udp.h>
#include <encoding/payloads/cert_payload.h>
#include <encoding/payloads/encrypted_payload.h>
typedef struct private_ike_auth_fill_t private_ike_auth_fill_t;
/**
* Private data of an ike_auth_fill_t object.
*/
struct private_ike_auth_fill_t {
/**
* Implements the hook_t interface.
*/
hook_t hook;
/**
* Alter requests or responses?
*/
bool req;
/**
* ID of message to alter.
*/
int id;
/**
* Number of bytes to fill IKE_AUTH up
*/
int bytes;
};
/** size of non ESP-Marker */
#define NON_ESP_MARKER_LEN 4
/** length of fixed encryption payload header */
#define ENCRYPTION_PAYLOAD_HEADER_LENGTH 4
/** length of fixed cert payload header */
#define CERT_PAYLOAD_HEADER_LENGTH 5
/**
* Calculate packet size on wire (without ethernet/IP header)
*/
static size_t calculate_wire_size(message_t *message, ike_sa_t *ike_sa)
{
enumerator_t *enumerator;
payload_t *payload;
size_t size = 0;
enumerator = message->create_payload_enumerator(message);
while (enumerator->enumerate(enumerator, &payload))
{
size += payload->get_length(payload);
}
enumerator->destroy(enumerator);
if (message->get_exchange_type(message) != IKE_SA_INIT)
{
keymat_t *keymat;
aead_t *aead;
size_t bs;
keymat = ike_sa->get_keymat(ike_sa);
aead = keymat->get_aead(keymat, FALSE);
if (aead)
{
bs = aead->get_block_size(aead);
size += ENCRYPTION_PAYLOAD_HEADER_LENGTH + NON_ESP_MARKER_LEN +
aead->get_icv_size(aead) + aead->get_iv_size(aead) +
(bs - (size % bs));
}
}
return sizeof(struct udphdr) + IKE_HEADER_LENGTH + size;
}
METHOD(listener_t, message, bool,
private_ike_auth_fill_t *this, ike_sa_t *ike_sa, message_t *message,
bool incoming, bool plain)
{
if (!incoming && plain &&
message->get_request(message) == this->req &&
message->get_message_id(message) == this->id)
{
cert_payload_t *pld;
size_t size, diff;
chunk_t data;
size = calculate_wire_size(message, ike_sa);
if (size < this->bytes - CERT_PAYLOAD_HEADER_LENGTH)
{
diff = this->bytes - size - CERT_PAYLOAD_HEADER_LENGTH;
data = chunk_alloc(diff);
memset(data.ptr, 0x12, data.len);
pld = cert_payload_create_custom(PLV2_CERTIFICATE, 201, data);
message->add_payload(message, &pld->payload_interface);
DBG1(DBG_CFG, "inserting %d dummy bytes certificate payload", diff);
}
}
return TRUE;
}
METHOD(hook_t, destroy, void,
private_ike_auth_fill_t *this)
{
free(this);
}
/**
* Create the IKE_AUTH fill hook
*/
hook_t *ike_auth_fill_hook_create(char *name)
{
private_ike_auth_fill_t *this;
INIT(this,
.hook = {
.listener = {
.message = _message,
},
.destroy = _destroy,
},
.req = conftest->test->get_bool(conftest->test,
"hooks.%s.request", TRUE, name),
.id = conftest->test->get_int(conftest->test,
"hooks.%s.id", 1, name),
.bytes = conftest->test->get_int(conftest->test,
"hooks.%s.bytes", 0, name),
);
return &this->hook;
}
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