/**
* $RCSfile$
* $Revision: $
* $Date: $
*
* Copyright 2003-2004 Jive Software.
*
* All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jivesoftware.smack;
import org.jivesoftware.smack.filter.PacketIDFilter;
import org.jivesoftware.smack.packet.Bind;
import org.jivesoftware.smack.packet.IQ;
import org.jivesoftware.smack.packet.Session;
import org.jivesoftware.smack.sasl.SASLMechanism;
import org.jivesoftware.smack.sasl.SASLPlainMechanism;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.util.*;
/**
* This class is responsible authenticating the user using SASL, binding the resource
* to the connection and establishing a session with the server.
*
* Once TLS has been negotiated (i.e. the connection has been secured) it is possible to
* register with the server, authenticate using Non-SASL or authenticate using SASL. If the
* server supports SASL then Smack will first try to authenticate using SASL. But if that
* fails then Non-SASL will be tried.
*
* The server may support many SASL mechanisms to use for authenticating. Out of the box
* Smack provides SASL PLAIN but it is possible to register new SASL Mechanisms. Use
* {@link #registerSASLMechanism(int, String, Class)} to add new mechanisms. See
* {@link SASLMechanism}.
*
* Once the user has been authenticated with SASL, it is necessary to bind a resource for
* the connection. If no resource is passed in {@link #authenticate(String, String, String)}
* then the server will assign a resource for the connection. In case a resource is passed
* then the server will receive the desired resource but may assign a modified resource for
* the connection.
*
* Once a resource has been binded and if the server supports sessions then Smack will establish
* a session so that instant messaging and presence functionalities may be used.
*
* @author Gaston Dombiak
*/
public class SASLAuthentication implements UserAuthentication {
private static Map implementedMechanisms = new HashMap();
private static List mechanismsPreferences = new ArrayList();
private XMPPConnection connection;
private Collection serverMechanisms = new ArrayList();
private SASLMechanism currentMechanism = null;
/**
* Boolean indicating if SASL negotiation has finished and was successful.
*/
private boolean saslNegotiated = false;
private boolean sessionSupported = false;
static {
// Register SASL mechanisms supported by Smack
registerSASLMechanism(0, "PLAIN", SASLPlainMechanism.class);
}
/**
* Registers a new SASL mechanism in the specified preference position. The client will try
* to authenticate using the most prefered SASL mechanism that is also supported by the server.
*
*
* Use the index parameter to set the level of preference of the new SASL mechanism.
* A value of 0 means that the mechanism is the most prefered one.
*
* @param index preference position amongst all the implemented SASL mechanism. Starts with 0.
* @param name common name of the SASL mechanism. E.g.: PLAIN, DIGEST-MD5 or KERBEROS_V4.
* @param mClass a SASLMechanism subclass.
*/
public static void registerSASLMechanism(int index, String name, Class mClass) {
implementedMechanisms.put(name, mClass);
mechanismsPreferences.add(index, name);
}
/**
* Unregisters an existing SASL mechanism. Once the mechanism has been unregistered it won't
* be possible to authenticate users using the removed SASL mechanism.
*
* @param name common name of the SASL mechanism. E.g.: PLAIN, DIGEST-MD5 or KERBEROS_V4.
*/
public static void unregisterSASLMechanism(String name) {
implementedMechanisms.remove(name);
mechanismsPreferences.remove(name);
}
/**
* Returns the registerd SASLMechanism classes sorted by the level of preference.
*
* @return the registerd SASLMechanism classes sorted by the level of preference.
*/
public static List getRegisterSASLMechanisms() {
List answer = new ArrayList();
for (Iterator it = mechanismsPreferences.iterator(); it.hasNext();) {
answer.add(implementedMechanisms.get(it.next()));
}
return answer;
}
SASLAuthentication(XMPPConnection connection) {
super();
this.connection = connection;
}
public String authenticate(String username, String password, String resource)
throws XMPPException {
// Locate the SASLMechanism to use
Class selected = null;
for (Iterator it = mechanismsPreferences.iterator(); it.hasNext();) {
String mechanism = (String) it.next();
if (implementedMechanisms.containsKey(mechanism) &&
serverMechanisms.contains(mechanism)) {
selected = (Class) implementedMechanisms.get(mechanism);
break;
}
}
if (selected != null) {
// A SASL mechanism was found. Authenticate using the selected mechanism and then
// proceed to bind a resource
try {
Constructor constructor = selected
.getConstructor(new Class[]{SASLAuthentication.class});
currentMechanism = (SASLMechanism) constructor.newInstance(new Object[]{this});
// Trigger SASL authentication with the selected mechanism
currentMechanism.authenticate(username, connection.getServiceName(), password);
// Wait until SASL negotiation finishes
synchronized (this) {
try {
wait(30000);
} catch (InterruptedException e) {
}
}
if (saslNegotiated) {
// We now need to bind a resource for the connection
// Open a new stream and wait for the response
connection.packetWriter.openStream();
// Wait until server sends response containing the element
synchronized (this) {
try {
wait(30000);
} catch (InterruptedException e) {
}
}
Bind bindResource = new Bind();
bindResource.setResource(resource);
PacketCollector collector = connection
.createPacketCollector(new PacketIDFilter(bindResource.getPacketID()));
// Send the packet
connection.sendPacket(bindResource);
// Wait up to a certain number of seconds for a response from the server.
Bind response = (Bind) collector
.nextResult(SmackConfiguration.getPacketReplyTimeout());
collector.cancel();
if (response == null) {
throw new XMPPException("No response from the server.");
}
// If the server replied with an error, throw an exception.
else if (response.getType() == IQ.Type.ERROR) {
throw new XMPPException(response.getError());
}
String userJID = response.getJid();
if (sessionSupported) {
Session session = new Session();
collector = connection
.createPacketCollector(new PacketIDFilter(session.getPacketID()));
// Send the packet
connection.sendPacket(session);
// Wait up to a certain number of seconds for a response from the server.
IQ ack = (IQ) collector
.nextResult(SmackConfiguration.getPacketReplyTimeout());
collector.cancel();
if (ack == null) {
throw new XMPPException("No response from the server.");
}
// If the server replied with an error, throw an exception.
else if (ack.getType() == IQ.Type.ERROR) {
throw new XMPPException(ack.getError());
}
}
return userJID;
} else {
// SASL authentication failed so try a Non-SASL authentication
return new NonSASLAuthentication(connection)
.authenticate(username, password, resource);
}
} catch (Exception e) {
e.printStackTrace();
// SASL authentication failed so try a Non-SASL authentication
return new NonSASLAuthentication(connection)
.authenticate(username, password, resource);
}
} else {
// No SASL method was found so try a Non-SASL authentication
return new NonSASLAuthentication(connection).authenticate(username, password, resource);
}
}
/**
* Sets the available SASL mechanism reported by the server. The server will report the
* available SASL mechanism once the TLS negotiation was successful. This information is
* stored and will be used when doing the authentication for logging in the user.
*
* @param mechanisms collection of strings with the available SASL mechanism reported
* by the server.
*/
void setAvailableSASLMethods(Collection mechanisms) {
this.serverMechanisms = mechanisms;
}
/**
* The server is challenging the SASL authentication we just sent. Forward the challenge
* to the current SASLMechanism we are using. The SASLMechanism will send a response to
* the server. The length of the challenge-response sequence varies according to the
* SASLMechanism in use.
*
* @param challenge a base64 encoded string representing the challenge.
* @throws IOException If a network error occures while authenticating.
*/
void challengeReceived(String challenge) throws IOException {
currentMechanism.challengeReceived(challenge);
}
/**
* Notification message saying that SASL authentication was successful. The next step
* would be to bind the resource.
*/
void authenticated() {
saslNegotiated = true;
synchronized (this) {
// Wake up the thread that is waiting in the #authenticate method
notify();
}
}
/**
* Notification message saying that the server requires the client to bind a
* resource to the stream.
*/
void bindingRequired() {
synchronized (this) {
// Wake up the thread that is waiting in the #authenticate method
notify();
}
}
public void send(String stanza) throws IOException {
connection.writer.write(stanza);
connection.writer.flush();
}
/**
* Notification message saying that the server supports sessions. When a server supports
* sessions the client needs to send a Session packet after successfully binding a resource
* for the session.
*/
void sessionsSupported() {
sessionSupported = true;
}
}