kexmanager.java

thinking in java4 src

package ch.ethz.ssh2.transport;

import java.io.IOException;
import java.security.SecureRandom;

import ch.ethz.ssh2.ConnectionInfo;
import ch.ethz.ssh2.DHGexParameters;
import ch.ethz.ssh2.ServerHostKeyVerifier;
import ch.ethz.ssh2.crypto.CryptoWishList;
import ch.ethz.ssh2.crypto.KeyMaterial;
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.dh.DhGroupExchange;
import ch.ethz.ssh2.crypto.digest.MAC;
import ch.ethz.ssh2.log.Logger;
import ch.ethz.ssh2.packets.PacketKexDHInit;
import ch.ethz.ssh2.packets.PacketKexDHReply;
import ch.ethz.ssh2.packets.PacketKexDhGexGroup;
import ch.ethz.ssh2.packets.PacketKexDhGexInit;
import ch.ethz.ssh2.packets.PacketKexDhGexReply;
import ch.ethz.ssh2.packets.PacketKexDhGexRequest;
import ch.ethz.ssh2.packets.PacketKexInit;
import ch.ethz.ssh2.packets.PacketNewKeys;
import ch.ethz.ssh2.packets.Packets;
import ch.ethz.ssh2.signature.DSAPublicKey;
import ch.ethz.ssh2.signature.DSASHA1Verify;
import ch.ethz.ssh2.signature.DSASignature;
import ch.ethz.ssh2.signature.RSAPublicKey;
import ch.ethz.ssh2.signature.RSASHA1Verify;
import ch.ethz.ssh2.signature.RSASignature;

/**
 * KexManager.
 * 
 * @author Christian Plattner, [e-mail]
 * @version $Id: KexManager.java,v 1.10 2006/02/14 19:43:15 cplattne Exp $
 */
public class KexManager
{
	private static final Logger log = Logger.getLogger(KexManager.class);

	KexState kxs;
	int kexCount = 0;
	KeyMaterial km;
	byte[] sessionId;
	ClientServerHello csh;

	final Object accessLock = new Object();
	ConnectionInfo lastConnInfo = null;

	boolean connectionClosed = false;

	boolean ignore_next_kex_packet = false;

	final TransportManager tm;

	CryptoWishList nextKEXcryptoWishList;
	DHGexParameters nextKEXdhgexParameters;

	ServerHostKeyVerifier verifier;
	final String hostname;
	final int port;
	final SecureRandom rnd;

	public KexManager(TransportManager tm, ClientServerHello csh, CryptoWishList initialCwl, String hostname, int port,
			ServerHostKeyVerifier keyVerifier, SecureRandom rnd)
	{
		this.tm = tm;
		this.csh = csh;
		this.nextKEXcryptoWishList = initialCwl;
		this.nextKEXdhgexParameters = new DHGexParameters();
		this.hostname = hostname;
		this.port = port;
		this.verifier = keyVerifier;
		this.rnd = rnd;
	}

	public ConnectionInfo getOrWaitForConnectionInfo(int minKexCount) throws IOException
	{
		synchronized (accessLock)
		{
			while (true)
			{
				if ((lastConnInfo != null) && (lastConnInfo.keyExchangeCounter >= minKexCount))
					return lastConnInfo;

				if (connectionClosed)
					throw (IOException) new IOException("Key exchange was not finished, connection is closed.")
							.initCause(tm.getReasonClosedCause());

				try
				{
					accessLock.wait();
				}
				catch (InterruptedException e)
				{
				}
			}
		}
	}

	private String getFirstMatch(String[] client, String[] server) throws NegotiateException
	{
		if (client == null || server == null)
			throw new IllegalArgumentException();

		if (client.length == 0)
			return null;

		for (int i = 0; i < client.length; i++)
		{
			for (int j = 0; j < server.length; j++)
			{
				if (client[i].equals(server[j]))
					return client[i];
			}
		}
		throw new NegotiateException();
	}

	private boolean compareFirstOfNameList(String[] a, String[] b)
	{
		if (a == null || b == null)
			throw new IllegalArgumentException();

		if ((a.length == 0) && (b.length == 0))
			return true;

		if ((a.length == 0) || (b.length == 0))
			return false;

		return (a[0].equals(b[0]));
	}

	private boolean isGuessOK(KexParameters cpar, KexParameters spar)
	{
		if (cpar == null || spar == null)
			throw new IllegalArgumentException();

		if (compareFirstOfNameList(cpar.kex_algorithms, spar.kex_algorithms) == false)
		{
			return false;
		}

		if (compareFirstOfNameList(cpar.server_host_key_algorithms, spar.server_host_key_algorithms) == false)
		{
			return false;
		}

		/*
		 * We do NOT check here if the other algorithms can be agreed on, this
		 * is just a check if kex_algorithms and server_host_key_algorithms were
		 * guessed right!
		 */

		return true;
	}

	private NegotiatedParameters mergeKexParameters(KexParameters client, KexParameters server)
	{
		NegotiatedParameters np = new NegotiatedParameters();

		try
		{
			np.kex_algo = getFirstMatch(client.kex_algorithms, server.kex_algorithms);

			log.log(20, "kex_algo=" + np.kex_algo);

			np.server_host_key_algo = getFirstMatch(client.server_host_key_algorithms,
					server.server_host_key_algorithms);

			log.log(20, "server_host_key_algo=" + np.server_host_key_algo);

			np.enc_algo_client_to_server = getFirstMatch(client.encryption_algorithms_client_to_server,
					server.encryption_algorithms_client_to_server);
			np.enc_algo_server_to_client = getFirstMatch(client.encryption_algorithms_server_to_client,
					server.encryption_algorithms_server_to_client);

			log.log(20, "enc_algo_client_to_server=" + np.enc_algo_client_to_server);
			log.log(20, "enc_algo_server_to_client=" + np.enc_algo_server_to_client);

			np.mac_algo_client_to_server = getFirstMatch(client.mac_algorithms_client_to_server,
					server.mac_algorithms_client_to_server);
			np.mac_algo_server_to_client = getFirstMatch(client.mac_algorithms_server_to_client,
					server.mac_algorithms_server_to_client);

			log.log(20, "mac_algo_client_to_server=" + np.mac_algo_client_to_server);
			log.log(20, "mac_algo_server_to_client=" + np.mac_algo_server_to_client);

			np.comp_algo_client_to_server = getFirstMatch(client.compression_algorithms_client_to_server,
					server.compression_algorithms_client_to_server);
			np.comp_algo_server_to_client = getFirstMatch(client.compression_algorithms_server_to_client,
					server.compression_algorithms_server_to_client);

			log.log(20, "comp_algo_client_to_server=" + np.comp_algo_client_to_server);
			log.log(20, "comp_algo_server_to_client=" + np.comp_algo_server_to_client);

		}
		catch (NegotiateException e)
		{
			return null;
		}

		try
		{
			np.lang_client_to_server = getFirstMatch(client.languages_client_to_server,
					server.languages_client_to_server);
		}
		catch (NegotiateException e1)
		{
			np.lang_client_to_server = null;
		}

		try
		{
			np.lang_server_to_client = getFirstMatch(client.languages_server_to_client,
					server.languages_server_to_client);
		}
		catch (NegotiateException e2)
		{
			np.lang_server_to_client = null;
		}

		if (isGuessOK(client, server))
			np.guessOK = true;

		return np;
	}

	public synchronized void initiateKEX(CryptoWishList cwl, DHGexParameters dhgex) throws IOException
	{
		nextKEXcryptoWishList = cwl;
		nextKEXdhgexParameters = dhgex;

		if (kxs == null)
		{
			kxs = new KexState();

			kxs.dhgexParameters = nextKEXdhgexParameters;
			PacketKexInit kp = new PacketKexInit(nextKEXcryptoWishList, rnd);
			kxs.localKEX = kp;
			tm.sendKexMessage(kp.getPayload());
		}
	}

	private boolean establishKeyMaterial()
	{
		try
		{
			int mac_cs_key_len = MAC.getKeyLen(kxs.np.mac_algo_client_to_server);
			int enc_cs_key_len = BlockCipherFactory.getKeySize(kxs.np.enc_algo_client_to_server);
			int enc_cs_block_len = BlockCipherFactory.getBlockSize(kxs.np.enc_algo_client_to_server);

			int mac_sc_key_len = MAC.getKeyLen(kxs.np.mac_algo_server_to_client);
			int enc_sc_key_len = BlockCipherFactory.getKeySize(kxs.np.enc_algo_server_to_client);
			int enc_sc_block_len = BlockCipherFactory.getBlockSize(kxs.np.enc_algo_server_to_client);

			km = KeyMaterial.create("SHA1", kxs.H, kxs.K, sessionId, enc_cs_key_len, enc_cs_block_len, mac_cs_key_len,
					enc_sc_key_len, enc_sc_block_len, mac_sc_key_len);
		}
		catch (IllegalArgumentException e)
		{
			return false;
		}
		return true;
	}

	private void finishKex() throws IOException
	{
		if (sessionId == null)
			sessionId = kxs.H;

		establishKeyMaterial();

		/* Tell the other side that we start using the new material */

		PacketNewKeys ign = new PacketNewKeys();
		tm.sendKexMessage(ign.getPayload());

		BlockCipher cbc;
		MAC mac;

		try
		{
			cbc = BlockCipherFactory.createCipher(kxs.np.enc_algo_client_to_server, true, 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.changeSendCipher(cbc, mac);
		tm.kexFinished();
	}

	public static final String[] getDefaultServerHostkeyAlgorithmList()
	{
		return new String[] { "ssh-rsa", "ssh-dss" };
	}

	public static final void checkServerHostkeyAlgorithmsList(String[] algos)
	{
		for (int i = 0; i < algos.length; i++)
		{