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/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of Qt Creator.
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
****************************************************************************/
#include "sshkeyexchange_p.h"
#include "sshbotanconversions_p.h"
#include "sshcapabilities_p.h"
#include "sshsendfacility_p.h"
#include "sshexception_p.h"
#include "sshincomingpacket_p.h"
#include <botan/botan.h>
#ifdef CREATOR_SSH_DEBUG
#include <iostream>
#endif
#include <string>
using namespace Botan;
namespace QSsh {
namespace Internal {
namespace {
// For debugging
void printNameList(const char *listName, const SshNameList &list)
{
#ifdef CREATOR_SSH_DEBUG
qDebug("%s:", listName);
foreach (const QByteArray &name, list.names)
qDebug("%s", name.constData());
#else
Q_UNUSED(listName);
Q_UNUSED(list);
#endif
}
#ifdef CREATOR_SSH_DEBUG
void printData(const char *name, const QByteArray &data)
{
std::cerr << std::hex;
qDebug("The client thinks the %s has length %d and is:", name, data.count());
for (int i = 0; i < data.count(); ++i)
std::cerr << (static_cast<unsigned int>(data.at(i)) & 0xff) << ' ';
std::cerr << std::endl;
}
#endif
} // anonymous namespace
SshKeyExchange::SshKeyExchange(SshSendFacility &sendFacility)
: m_sendFacility(sendFacility)
{
}
SshKeyExchange::~SshKeyExchange() {}
void SshKeyExchange::sendKexInitPacket(const QByteArray &serverId)
{
m_serverId = serverId;
m_clientKexInitPayload = m_sendFacility.sendKeyExchangeInitPacket();
}
bool SshKeyExchange::sendDhInitPacket(const SshIncomingPacket &serverKexInit)
{
#ifdef CREATOR_SSH_DEBUG
qDebug("server requests key exchange");
#endif
serverKexInit.printRawBytes();
SshKeyExchangeInit kexInitParams
= serverKexInit.extractKeyExchangeInitData();
printNameList("Key Algorithms", kexInitParams.keyAlgorithms);
printNameList("Server Host Key Algorithms", kexInitParams.serverHostKeyAlgorithms);
printNameList("Encryption algorithms client to server", kexInitParams.encryptionAlgorithmsClientToServer);
printNameList("Encryption algorithms server to client", kexInitParams.encryptionAlgorithmsServerToClient);
printNameList("MAC algorithms client to server", kexInitParams.macAlgorithmsClientToServer);
printNameList("MAC algorithms server to client", kexInitParams.macAlgorithmsServerToClient);
printNameList("Compression algorithms client to server", kexInitParams.compressionAlgorithmsClientToServer);
printNameList("Compression algorithms client to server", kexInitParams.compressionAlgorithmsClientToServer);
printNameList("Languages client to server", kexInitParams.languagesClientToServer);
printNameList("Languages server to client", kexInitParams.languagesServerToClient);
#ifdef CREATOR_SSH_DEBUG
qDebug("First packet follows: %d", kexInitParams.firstKexPacketFollows);
#endif
const QByteArray &keyAlgo
= SshCapabilities::findBestMatch(SshCapabilities::KeyExchangeMethods,
kexInitParams.keyAlgorithms.names);
m_serverHostKeyAlgo
= SshCapabilities::findBestMatch(SshCapabilities::PublicKeyAlgorithms,
kexInitParams.serverHostKeyAlgorithms.names);
m_encryptionAlgo
= SshCapabilities::findBestMatch(SshCapabilities::EncryptionAlgorithms,
kexInitParams.encryptionAlgorithmsClientToServer.names);
m_decryptionAlgo
= SshCapabilities::findBestMatch(SshCapabilities::EncryptionAlgorithms,
kexInitParams.encryptionAlgorithmsServerToClient.names);
m_c2sHMacAlgo
= SshCapabilities::findBestMatch(SshCapabilities::MacAlgorithms,
kexInitParams.macAlgorithmsClientToServer.names);
m_s2cHMacAlgo
= SshCapabilities::findBestMatch(SshCapabilities::MacAlgorithms,
kexInitParams.macAlgorithmsServerToClient.names);
SshCapabilities::findBestMatch(SshCapabilities::CompressionAlgorithms,
kexInitParams.compressionAlgorithmsClientToServer.names);
SshCapabilities::findBestMatch(SshCapabilities::CompressionAlgorithms,
kexInitParams.compressionAlgorithmsServerToClient.names);
AutoSeeded_RNG rng;
m_dhKey.reset(new DH_PrivateKey(rng,
DL_Group(botanKeyExchangeAlgoName(keyAlgo))));
m_serverKexInitPayload = serverKexInit.payLoad();
m_sendFacility.sendKeyDhInitPacket(m_dhKey->get_y());
return kexInitParams.firstKexPacketFollows;
}
void SshKeyExchange::sendNewKeysPacket(const SshIncomingPacket &dhReply,
const QByteArray &clientId)
{
const SshKeyExchangeReply &reply
= dhReply.extractKeyExchangeReply(m_serverHostKeyAlgo);
if (reply.f <= 0 || reply.f >= m_dhKey->group_p()) {
throw SSH_SERVER_EXCEPTION(SSH_DISCONNECT_KEY_EXCHANGE_FAILED,
"Server sent invalid f.");
}
QByteArray concatenatedData = AbstractSshPacket::encodeString(clientId);
concatenatedData += AbstractSshPacket::encodeString(m_serverId);
concatenatedData += AbstractSshPacket::encodeString(m_clientKexInitPayload);
concatenatedData += AbstractSshPacket::encodeString(m_serverKexInitPayload);
concatenatedData += reply.k_s;
concatenatedData += AbstractSshPacket::encodeMpInt(m_dhKey->get_y());
concatenatedData += AbstractSshPacket::encodeMpInt(reply.f);
const BigInt k = power_mod(reply.f, m_dhKey->get_x(), m_dhKey->get_domain().get_p());
m_k = AbstractSshPacket::encodeMpInt(k);
concatenatedData += m_k;
m_hash.reset(get_hash(botanSha1Name()));
const SecureVector<byte> &hashResult
= m_hash->process(convertByteArray(concatenatedData),
concatenatedData.size());
m_h = convertByteArray(hashResult);
#ifdef CREATOR_SSH_DEBUG
printData("Client Id", AbstractSshPacket::encodeString(clientId));
printData("Server Id", AbstractSshPacket::encodeString(m_serverId));
printData("Client Payload", AbstractSshPacket::encodeString(m_clientKexInitPayload));
printData("Server payload", AbstractSshPacket::encodeString(m_serverKexInitPayload));
printData("K_S", reply.k_s);
printData("y", AbstractSshPacket::encodeMpInt(m_dhKey->get_y()));
printData("f", AbstractSshPacket::encodeMpInt(reply.f));
printData("K", m_k);
printData("Concatenated data", concatenatedData);
printData("H", m_h);
#endif // CREATOR_SSH_DEBUG
QScopedPointer<Public_Key> sigKey;
QScopedPointer<PK_Verifier> verifier;
if (m_serverHostKeyAlgo == SshCapabilities::PubKeyDss) {
const DL_Group group(reply.parameters.at(0), reply.parameters.at(1),
reply.parameters.at(2));
DSA_PublicKey * const dsaKey
= new DSA_PublicKey(group, reply.parameters.at(3));
sigKey.reset(dsaKey);
verifier.reset(new PK_Verifier(*dsaKey, botanEmsaAlgoName(SshCapabilities::PubKeyDss)));
} else if (m_serverHostKeyAlgo == SshCapabilities::PubKeyRsa) {
RSA_PublicKey * const rsaKey
= new RSA_PublicKey(reply.parameters.at(1), reply.parameters.at(0));
sigKey.reset(rsaKey);
verifier.reset(new PK_Verifier(*rsaKey, botanEmsaAlgoName(SshCapabilities::PubKeyRsa)));
} else {
Q_ASSERT(!"Impossible: Neither DSS nor RSA!");
}
const byte * const botanH = convertByteArray(m_h);
const Botan::byte * const botanSig
= convertByteArray(reply.signatureBlob);
if (!verifier->verify_message(botanH, m_h.size(), botanSig,
reply.signatureBlob.size())) {
throw SSH_SERVER_EXCEPTION(SSH_DISCONNECT_KEY_EXCHANGE_FAILED,
"Invalid signature in SSH_MSG_KEXDH_REPLY packet.");
}
m_sendFacility.sendNewKeysPacket();
}
} // namespace Internal
} // namespace QSsh
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