--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/src/main/java/ch/ethz/ssh2/transport/ClientKexManager.java	Thu Dec 03 11:23:55 2015 -0800
@@ -0,0 +1,326 @@
+/*
+ * 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 java.security.DigestException;
+import java.security.SecureRandom;
+import java.security.interfaces.DSAPublicKey;
+import java.security.interfaces.ECPublicKey;
+import java.security.interfaces.RSAPublicKey;
+
+import ch.ethz.ssh2.ConnectionInfo;
+import ch.ethz.ssh2.PacketTypeException;
+import ch.ethz.ssh2.ServerHostKeyVerifier;
+import ch.ethz.ssh2.compression.CompressionFactory;
+import ch.ethz.ssh2.compression.Compressor;
+import ch.ethz.ssh2.crypto.CryptoWishList;
+import ch.ethz.ssh2.crypto.cipher.BlockCipher;
+import ch.ethz.ssh2.crypto.cipher.BlockCipherFactory;
+import ch.ethz.ssh2.crypto.dh.GenericDhExchange;
+import ch.ethz.ssh2.crypto.dh.DhGroupExchange;
+import ch.ethz.ssh2.crypto.digest.MAC;
+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.PacketKexDhGexRequestOld;
+import ch.ethz.ssh2.packets.PacketKexInit;
+import ch.ethz.ssh2.packets.Packets;
+import ch.ethz.ssh2.signature.DSASHA1Verify;
+import ch.ethz.ssh2.signature.ECDSASHA2Verify;
+import ch.ethz.ssh2.signature.RSASHA1Verify;
+
+/**
+ * @version $Id: ClientKexManager.java 160 2014-05-01 14:30:26Z dkocher@sudo.ch $
+ */
+public class ClientKexManager extends KexManager {
+
+    private final ServerHostKeyVerifier verifier;
+
+    private final String hostname;
+
+    private final int port;
+
+    public ClientKexManager(TransportManager tm, ClientServerHello csh, CryptoWishList initialCwl, String hostname, int port,
+                            ServerHostKeyVerifier keyVerifier, SecureRandom rnd) {
+        super(tm, csh, initialCwl, rnd);
+        this.hostname = hostname;
+        this.port = port;
+        this.verifier = keyVerifier;
+    }
+
+    protected boolean verifySignature(byte[] sig, byte[] hostkey) throws IOException {
+        if (kxs.np.server_host_key_algo.startsWith("ecdsa-sha2-")) {
+            byte[] rs = ECDSASHA2Verify.decodeSSHECDSASignature(sig);
+            ECPublicKey epk = ECDSASHA2Verify.decodeSSHECDSAPublicKey(hostkey);
+            log.debug("Verifying ecdsa signature");
+            return ECDSASHA2Verify.verifySignature(kxs.H, rs, epk);
+        }
+
+        if (kxs.np.server_host_key_algo.equals("ssh-rsa")) {
+            byte[] rs = RSASHA1Verify.decodeSSHRSASignature(sig);
+            RSAPublicKey rpk = RSASHA1Verify.decodeSSHRSAPublicKey(hostkey);
+            log.debug("Verifying ssh-rsa signature");
+            return RSASHA1Verify.verifySignature(kxs.H, rs, rpk);
+        }
+
+        if (kxs.np.server_host_key_algo.equals("ssh-dss")) {
+            byte[] ds = DSASHA1Verify.decodeSSHDSASignature(sig);
+            DSAPublicKey dpk = DSASHA1Verify.decodeSSHDSAPublicKey(hostkey);
+            log.debug("Verifying ssh-dss signature");
+            return DSASHA1Verify.verifySignature(kxs.H, ds, dpk);
+        }
+
+        throw new IOException("Unknown server host key algorithm '" + kxs.np.server_host_key_algo + "'");
+    }
+
+    public void handleFailure(final IOException failure) {
+        synchronized (accessLock) {
+            connectionClosed = true;
+            accessLock.notifyAll();
+        }
+    }
+
+    public synchronized void handleMessage(byte[] msg) throws IOException {
+        PacketKexInit kip;
+
+        if (msg == null) {
+            synchronized (accessLock) {
+                connectionClosed = true;
+                accessLock.notifyAll();
+                return;
+            }
+        }
+
+        log.debug(String.format("client kex manager, packet type %d", msg[0]));
+
+        if ((kxs == null) && (msg[0] != Packets.SSH_MSG_KEXINIT)) {
+            throw new PacketTypeException(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 PacketTypeException(msg[0]);
+            }
+
+            if (kxs == null) {
+                /*
+                 * Ah, OK, peer wants to do KEX. Let's be nice and play
+                 * together.
+                 */
+                kxs = new KexState();
+                kxs.dhgexParameters = nextKEXdhgexParameters;
+                kip = new PacketKexInit(nextKEXcryptoWishList, rnd);
+                kxs.localKEX = kip;
+                tm.sendKexMessage(kip.getPayload());
+            }
+
+            kip = new PacketKexInit(msg);
+            kxs.remoteKEX = kip;
+            kxs.np = mergeKexParameters(kxs.localKEX.getKexParameters(), kxs.remoteKEX.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-group-exchange-sha1") ||
+                    kxs.np.kex_algo.equals("diffie-hellman-group-exchange-sha256")) {
+                if (kxs.dhgexParameters.getMin_group_len() == 0) {
+                    PacketKexDhGexRequestOld dhgexreq = new PacketKexDhGexRequestOld(kxs.dhgexParameters);
+                    tm.sendKexMessage(dhgexreq.getPayload());
+                }
+                else {
+                    PacketKexDhGexRequest dhgexreq = new PacketKexDhGexRequest(kxs.dhgexParameters);
+                    tm.sendKexMessage(dhgexreq.getPayload());
+                }
+
+                if (kxs.np.kex_algo.endsWith("sha1")) {
+                    kxs.hashAlgo = "SHA1";
+                }
+                else {
+                    kxs.hashAlgo = "SHA2";
+                }
+
+                kxs.state = 1;
+                return;
+            }
+
+            if (kxs.np.kex_algo.equals("diffie-hellman-group1-sha1")  ||
+                kxs.np.kex_algo.equals("diffie-hellman-group14-sha1") ||
+                kxs.np.kex_algo.equals("ecdh-sha2-nistp256")          ||
+                kxs.np.kex_algo.equals("ecdh-sha2-nistp384")          ||
+                kxs.np.kex_algo.equals("ecdh-sha2-nistp521")) {
+                kxs.dhx = GenericDhExchange.getInstance(kxs.np.kex_algo);
+                kxs.dhx.init(kxs.np.kex_algo);
+                kxs.hashAlgo = kxs.dhx.getHashAlgo();
+                PacketKexDHInit kp = new PacketKexDHInit(kxs.dhx.getE());
+                tm.sendKexMessage(kp.getPayload());
+                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;
+            Compressor comp;
+
+            try {
+                cbc = BlockCipherFactory.createCipher(kxs.np.enc_algo_server_to_client, false,
+                                                      km.enc_key_server_to_client, km.initial_iv_server_to_client);
+
+                try {
+                    mac = new MAC(kxs.np.mac_algo_server_to_client, km.integrity_key_server_to_client);
+                }
+                catch (DigestException e) {
+                    throw new IOException(e);
+                }
+
+                comp = CompressionFactory.createCompressor(kxs.np.comp_algo_server_to_client);
+            }
+            catch (IllegalArgumentException e) {
+                throw new IOException(e.getMessage());
+            }
+
+            tm.changeRecvCipher(cbc, mac);
+            tm.changeRecvCompression(comp);
+            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-group-exchange-sha1") ||
+                kxs.np.kex_algo.equals("diffie-hellman-group-exchange-sha256")) {
+            if (kxs.state == 1) {
+                PacketKexDhGexGroup dhgexgrp = new PacketKexDhGexGroup(msg);
+                kxs.dhgx = new DhGroupExchange(dhgexgrp.getP(), dhgexgrp.getG());
+                kxs.dhgx.init(rnd);
+                PacketKexDhGexInit dhgexinit = new PacketKexDhGexInit(kxs.dhgx.getE());
+                tm.sendKexMessage(dhgexinit.getPayload());
+                kxs.state = 2;
+                return;
+            }
+
+            if (kxs.state == 2) {
+                PacketKexDhGexReply dhgexrpl = new PacketKexDhGexReply(msg);
+                kxs.remote_hostkey = dhgexrpl.getHostKey();
+
+                if (verifier != null) {
+                    try {
+                        if (!verifier.verifyServerHostKey(hostname, port, kxs.np.server_host_key_algo, kxs.remote_hostkey)) {
+                            throw new IOException("The server host key was not accepted by the verifier callback");
+                        }
+                    }
+                    catch (Exception e) {
+                        throw new IOException(
+                            "The server host key was not accepted by the verifier callback.", e);
+                    }
+                }
+
+                kxs.dhgx.setF(dhgexrpl.getF());
+
+                try {
+                    kxs.H = kxs.dhgx.calculateH(kxs.hashAlgo, csh.getClientString(), csh.getServerString(),
+                                                kxs.localKEX.getPayload(), kxs.remoteKEX.getPayload(), dhgexrpl.getHostKey(),
+                                                kxs.dhgexParameters);
+                }
+                catch (IllegalArgumentException e) {
+                    throw new IOException("KEX error.", e);
+                }
+
+                if (!verifySignature(dhgexrpl.getSignature(), kxs.remote_hostkey)) {
+                    throw new IOException("Invalid remote host key signature");
+                }
+
+                kxs.K = kxs.dhgx.getK();
+                finishKex(true);
+                kxs.state = -1;
+                return;
+            }
+
+            throw new IllegalStateException("Illegal State in KEX Exchange!");
+        }
+
+        if (kxs.np.kex_algo.equals("diffie-hellman-group1-sha1")  ||
+                kxs.np.kex_algo.equals("diffie-hellman-group14-sha1") ||
+                kxs.np.kex_algo.equals("ecdh-sha2-nistp256")          ||
+                kxs.np.kex_algo.equals("ecdh-sha2-nistp384")          ||
+                kxs.np.kex_algo.equals("ecdh-sha2-nistp521")) {
+            if (kxs.state == 1) {
+                PacketKexDHReply dhr = new PacketKexDHReply(msg);
+                kxs.remote_hostkey = dhr.getHostKey();
+
+                if (verifier != null) {
+                    try {
+                        if (!verifier.verifyServerHostKey(hostname, port, kxs.np.server_host_key_algo, kxs.remote_hostkey)) {
+                            throw new IOException("The server host key was not accepted by the verifier callback");
+                        }
+                    }
+                    catch (Exception e) {
+                        throw new IOException("The server host key was not accepted by the verifier callback", e);
+                    }
+                }
+
+                kxs.dhx.setF(dhr.getF().toByteArray());
+
+                try {
+                    kxs.H = kxs.dhx.calculateH(csh.getClientString(), csh.getServerString(), kxs.localKEX.getPayload(),
+                                               kxs.remoteKEX.getPayload(), dhr.getHostKey());
+                }
+                catch (IllegalArgumentException e) {
+                    throw new IOException("KEX error.", e);
+                }
+
+                if (!verifySignature(dhr.getSignature(), kxs.remote_hostkey)) {
+                    throw new IOException("Invalid remote host key signature");
+                }
+
+                kxs.K = kxs.dhx.getK();
+                finishKex(true);
+                kxs.state = -1;
+                return;
+            }
+        }
+
+        throw new IllegalStateException(String.format("Unknown KEX method %s", kxs.np.kex_algo));
+    }
+}