/*
* Copyright (c) 2006-2013 Christian Plattner. All rights reserved.
* Please refer to the LICENSE.txt for licensing details.
*/
package ch.ethz.ssh2.transport;
import java.io.IOException;
import ch.ethz.ssh2.ConnectionInfo;
import ch.ethz.ssh2.auth.ServerAuthenticationManager;
import ch.ethz.ssh2.crypto.cipher.BlockCipher;
import ch.ethz.ssh2.crypto.cipher.BlockCipherFactory;
import ch.ethz.ssh2.crypto.dh.DhExchange;
import ch.ethz.ssh2.crypto.digest.MAC;
import ch.ethz.ssh2.packets.PacketKexDHInit;
import ch.ethz.ssh2.packets.PacketKexDHReply;
import ch.ethz.ssh2.packets.PacketKexInit;
import ch.ethz.ssh2.packets.Packets;
import ch.ethz.ssh2.server.ServerConnectionState;
import ch.ethz.ssh2.signature.DSASHA1Verify;
import ch.ethz.ssh2.signature.DSASignature;
import ch.ethz.ssh2.signature.RSASHA1Verify;
import ch.ethz.ssh2.signature.RSASignature;
public class ServerKexManager extends KexManager
{
private final ServerConnectionState state;
private boolean authenticationStarted = false;
public ServerKexManager(ServerConnectionState state)
{
super(state.tm, state.csh, state.next_cryptoWishList, state.generator);
this.state = state;
}
public void handleMessage(byte[] msg, int msglen) throws IOException
{
PacketKexInit kip;
if (msg == null)
{
synchronized (accessLock)
{
connectionClosed = true;
accessLock.notifyAll();
return;
}
}
if ((kxs == null) && (msg[0] != Packets.SSH_MSG_KEXINIT))
throw new IOException("Unexpected KEX message (type " + msg[0] + ")");
if (ignore_next_kex_packet)
{
ignore_next_kex_packet = false;
return;
}
if (msg[0] == Packets.SSH_MSG_KEXINIT)
{
if ((kxs != null) && (kxs.state != 0))
throw new IOException("Unexpected SSH_MSG_KEXINIT message during on-going kex exchange!");
if (kxs == null)
{
/*
* Ah, OK, peer wants to do KEX. Let's be nice and play
* together.
*/
kxs = new KexState();
kxs.local_dsa_key = nextKEXdsakey;
kxs.local_rsa_key = nextKEXrsakey;
kxs.dhgexParameters = nextKEXdhgexParameters;
kip = new PacketKexInit(nextKEXcryptoWishList, rnd);
kxs.localKEX = kip;
tm.sendKexMessage(kip.getPayload());
}
kip = new PacketKexInit(msg, 0, msglen);
kxs.remoteKEX = kip;
kxs.np = mergeKexParameters(kxs.remoteKEX.getKexParameters(), kxs.localKEX.getKexParameters());
if (kxs.np == null)
throw new IOException("Cannot negotiate, proposals do not match.");
if (kxs.remoteKEX.isFirst_kex_packet_follows() && (kxs.np.guessOK == false))
{
/*
* Guess was wrong, we need to ignore the next kex packet.
*/
ignore_next_kex_packet = true;
}
if (kxs.np.kex_algo.equals("diffie-hellman-group1-sha1")
|| kxs.np.kex_algo.equals("diffie-hellman-group14-sha1"))
{
kxs.dhx = new DhExchange();
if (kxs.np.kex_algo.equals("diffie-hellman-group1-sha1"))
kxs.dhx.serverInit(1, rnd);
else
kxs.dhx.serverInit(14, rnd);
kxs.state = 1;
return;
}
throw new IllegalStateException("Unkown KEX method!");
}
if (msg[0] == Packets.SSH_MSG_NEWKEYS)
{
if (km == null)
throw new IOException("Peer sent SSH_MSG_NEWKEYS, but I have no key material ready!");
BlockCipher cbc;
MAC mac;
try
{
cbc = BlockCipherFactory.createCipher(kxs.np.enc_algo_client_to_server, false,
km.enc_key_client_to_server, km.initial_iv_client_to_server);
mac = new MAC(kxs.np.mac_algo_client_to_server, km.integrity_key_client_to_server);
}
catch (IllegalArgumentException e1)
{
throw new IOException("Fatal error during MAC startup!");
}
tm.changeRecvCipher(cbc, mac);
ConnectionInfo sci = new ConnectionInfo();
kexCount++;
sci.keyExchangeAlgorithm = kxs.np.kex_algo;
sci.keyExchangeCounter = kexCount;
sci.clientToServerCryptoAlgorithm = kxs.np.enc_algo_client_to_server;
sci.serverToClientCryptoAlgorithm = kxs.np.enc_algo_server_to_client;
sci.clientToServerMACAlgorithm = kxs.np.mac_algo_client_to_server;
sci.serverToClientMACAlgorithm = kxs.np.mac_algo_server_to_client;
sci.serverHostKeyAlgorithm = kxs.np.server_host_key_algo;
sci.serverHostKey = kxs.remote_hostkey;
synchronized (accessLock)
{
lastConnInfo = sci;
accessLock.notifyAll();
}
kxs = null;
return;
}
if ((kxs == null) || (kxs.state == 0))
throw new IOException("Unexpected Kex submessage!");
if (kxs.np.kex_algo.equals("diffie-hellman-group1-sha1")
|| kxs.np.kex_algo.equals("diffie-hellman-group14-sha1"))
{
if (kxs.state == 1)
{
PacketKexDHInit dhi = new PacketKexDHInit(msg, 0, msglen);
kxs.dhx.setE(dhi.getE());
byte[] hostKey = null;
if (kxs.np.server_host_key_algo.equals("ssh-rsa"))
{
hostKey = RSASHA1Verify.encodeSSHRSAPublicKey(kxs.local_rsa_key.getPublicKey());
}
if (kxs.np.server_host_key_algo.equals("ssh-dss"))
{
hostKey = DSASHA1Verify.encodeSSHDSAPublicKey(kxs.local_dsa_key.getPublicKey());
}
try
{
kxs.H = kxs.dhx.calculateH(csh.getClientString(), csh.getServerString(),
kxs.remoteKEX.getPayload(), kxs.localKEX.getPayload(), hostKey);
}
catch (IllegalArgumentException e)
{
throw (IOException) new IOException("KEX error.").initCause(e);
}
kxs.K = kxs.dhx.getK();
byte[] signature = null;
if (kxs.np.server_host_key_algo.equals("ssh-rsa"))
{
RSASignature rs = RSASHA1Verify.generateSignature(kxs.H, kxs.local_rsa_key);
signature = RSASHA1Verify.encodeSSHRSASignature(rs);
}
if (kxs.np.server_host_key_algo.equals("ssh-dss"))
{
DSASignature ds = DSASHA1Verify.generateSignature(kxs.H, kxs.local_dsa_key, rnd);
signature = DSASHA1Verify.encodeSSHDSASignature(ds);
}
PacketKexDHReply dhr = new PacketKexDHReply(hostKey, kxs.dhx.getF(), signature);
tm.sendKexMessage(dhr.getPayload());
finishKex(false);
kxs.state = -1;
if (authenticationStarted == false)
{
authenticationStarted = true;
state.am = new ServerAuthenticationManager(state);
}
return;
}
}
throw new IllegalStateException("Unkown KEX method! (" + kxs.np.kex_algo + ")");
}
}