wanproxy/ssh/ssh_session.cc
2015-08-31 14:01:44 +02:00

112 lines
4.5 KiB
C++

/*
* Copyright (c) 2012 Juli Mallett. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <common/buffer.h>
#include <ssh/ssh_encryption.h>
#include <ssh/ssh_key_exchange.h>
#include <ssh/ssh_mac.h>
#include <ssh/ssh_session.h>
void
SSH::Session::activate_chosen(void)
{
const Buffer *local_to_remote_iv_;
const Buffer *remote_to_local_iv_;
const Buffer *local_to_remote_key_;
const Buffer *remote_to_local_key_;
/*
* XXX
* Need to free instances in active_algorithms_.
*/
active_algorithms_ = chosen_algorithms_;
if (active_algorithms_.client_to_server_.encryption_ != NULL) {
client_to_server_iv_ = generate_key("A", active_algorithms_.client_to_server_.encryption_->iv_size());
client_to_server_key_ = generate_key("C", active_algorithms_.client_to_server_.encryption_->key_size());
}
if (active_algorithms_.server_to_client_.encryption_ != NULL) {
server_to_client_iv_ = generate_key("B", active_algorithms_.server_to_client_.encryption_->iv_size());
server_to_client_key_ = generate_key("D", active_algorithms_.server_to_client_.encryption_->key_size());
}
if (active_algorithms_.client_to_server_.mac_ != NULL) {
client_to_server_integrity_key_ = generate_key("E", active_algorithms_.client_to_server_.mac_->key_size());
if (!active_algorithms_.client_to_server_.mac_->initialize(&client_to_server_integrity_key_))
HALT("/ssh/session") << "Failed to activate client-to-server MAC.";
}
if (active_algorithms_.server_to_client_.mac_ != NULL) {
server_to_client_integrity_key_ = generate_key("F", active_algorithms_.server_to_client_.mac_->key_size());
if (!active_algorithms_.server_to_client_.mac_->initialize(&server_to_client_integrity_key_))
HALT("/ssh/session") << "Failed to activate server-to-client MAC.";
}
if (active_algorithms_.local_to_remote_->encryption_ != NULL) {
if (role_ == ClientRole) {
local_to_remote_iv_ = &client_to_server_iv_;
local_to_remote_key_ = &client_to_server_key_;
} else {
local_to_remote_iv_ = &server_to_client_iv_;
local_to_remote_key_ = &server_to_client_key_;
}
if (!active_algorithms_.local_to_remote_->encryption_->initialize(CryptoEncryption::Encrypt, local_to_remote_key_, local_to_remote_iv_))
HALT("/ssh/session") << "Failed to initialize local-to-remote encryption.";
}
if (active_algorithms_.remote_to_local_->encryption_ != NULL) {
if (role_ == ClientRole) {
remote_to_local_iv_ = &server_to_client_iv_;
remote_to_local_key_ = &server_to_client_key_;
} else {
remote_to_local_iv_ = &client_to_server_iv_;
remote_to_local_key_ = &client_to_server_key_;
}
if (!active_algorithms_.remote_to_local_->encryption_->initialize(CryptoEncryption::Decrypt, remote_to_local_key_, remote_to_local_iv_))
HALT("/ssh/session") << "Failed to initialize local-to-remote encryption.";
}
}
Buffer
SSH::Session::generate_key(const std::string& x, unsigned key_size)
{
Buffer key;
while (key.length() < key_size) {
Buffer input;
input.append(shared_secret_);
input.append(exchange_hash_);
if (key.empty()) {
input.append(x);
input.append(session_id_);
} else {
input.append(key);
}
if (!active_algorithms_.key_exchange_->hash(&key, &input))
HALT("/ssh/session") << "Hash failed in generating key.";
}
if (key.length() > key_size)
key.truncate(key_size);
return (key);
}