/**
* $RCSfile$
* $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.SASLAnonymous;
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.<p>
*
* 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.<p>
*
* 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}.<p>
*
* 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.<p>
*
* 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<String, Class> implementedMechanisms = new HashMap<String, Class>();
private static List<String> mechanismsPreferences = new ArrayList<String>();
private XMPPConnection connection;
private Collection<String> serverMechanisms = new ArrayList<String>();
private SASLMechanism currentMechanism = null;
/**
* Boolean indicating if SASL negotiation has finished and was successful.
*/
private boolean saslNegotiated = false;
/**
* Boolean indication if SASL authentication has failed. When failed the server may end
* the connection.
*/
private boolean saslFailed = false;
private boolean resourceBinded = 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.
* <p/>
* <p/>
* Use the <tt>index</tt> 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<Class> getRegisterSASLMechanisms() {
List<Class> answer = new ArrayList<Class>();
for (String mechanismsPreference : mechanismsPreferences) {
answer.add(implementedMechanisms.get(mechanismsPreference));
}
return answer;
}
SASLAuthentication(XMPPConnection connection) {
super();
this.connection = connection;
}
/**
* Returns true if the server offered ANONYMOUS SASL as a way to authenticate users.
*
* @return true if the server offered ANONYMOUS SASL as a way to authenticate users.
*/
public boolean hasAnonymousAuthentication() {
return serverMechanisms.contains("ANONYMOUS");
}
/**
* Returns true if the server offered SASL authentication besides ANONYMOUS SASL.
*
* @return true if the server offered SASL authentication besides ANONYMOUS SASL.
*/
public boolean hasNonAnonymousAuthentication() {
if (!serverMechanisms.isEmpty()) {
// Check that anonymous sasl is not the only supported mechanism
if (serverMechanisms.size() == 1) {
return !hasAnonymousAuthentication();
}
return true;
}
return false;
}
/**
* Performs SASL authentication of the specified user. If SASL authentication was successful
* then resource binding and session establishment will be performed. This method will return
* the full JID provided by the server while binding a resource to the connection.<p>
*
* The server may assign a full JID with a username or resource different than the requested
* by this method.
*
* @param username the username that is authenticating with the server.
* @param password the password to send to the server.
* @param resource the desired resource.
* @return the full JID provided by the server while binding a resource to the connection.
* @throws XMPPException if an error occures while authenticating.
*/
public String authenticate(String username, String password, String resource)
throws XMPPException {
// Locate the SASLMechanism to use
Class selected = null;
for (String mechanism : mechanismsPreferences) {
if (implementedMechanisms.containsKey(mechanism) &&
serverMechanisms.contains(mechanism)) {
selected = 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) {
if (!saslNegotiated && !saslFailed) {
try {
wait(30000);
} catch (InterruptedException e) {
}
}
}
if (saslFailed) {
// SASL authentication failed and the server may have closed the connection
// so throw an exception
throw new XMPPException("SASL authentication failed");
}
if (saslNegotiated) {
// Bind a resource for this connection and
return bindResourceAndEstablishSession(resource);
} else {
// SASL authentication failed so try a Non-SASL authentication
return new NonSASLAuthentication(connection)
.authenticate(username, password, resource);
}
}
catch (XMPPException e) {
throw e;
}
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);
}
}
/**
* Performs ANONYMOUS SASL authentication. If SASL authentication was successful
* then resource binding and session establishment will be performed. This method will return
* the full JID provided by the server while binding a resource to the connection.<p>
*
* The server will assign a full JID with a randomly generated resource and possibly with
* no username.
*
* @return the full JID provided by the server while binding a resource to the connection.
* @throws XMPPException if an error occures while authenticating.
*/
public String authenticateAnonymously() throws XMPPException {
try {
currentMechanism = new SASLAnonymous(this);
currentMechanism.authenticate(null, null, null);
// Wait until SASL negotiation finishes
synchronized (this) {
if (!saslNegotiated && !saslFailed) {
try {
wait(5000);
} catch (InterruptedException e) {
}
}
}
if (saslFailed) {
// SASL authentication failed and the server may have closed the connection
// so throw an exception
throw new XMPPException("SASL authentication failed");
}
if (saslNegotiated) {
// Bind a resource for this connection and
return bindResourceAndEstablishSession(null);
}
else {
return new NonSASLAuthentication(connection).authenticateAnonymously();
}
} catch (IOException e) {
return new NonSASLAuthentication(connection).authenticateAnonymously();
}
}
private String bindResourceAndEstablishSession(String resource) throws XMPPException {
// Wait until server sends response containing the <bind> element
synchronized (this) {
if (!resourceBinded) {
try {
wait(30000);
} catch (InterruptedException e) {
}
}
}
if (!resourceBinded) {
// Server never offered resource binding
throw new XMPPException("Resource binding not offered by server");
}
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());
}
}
else {
// Server never offered session establishment
throw new XMPPException("Session establishment not offered by server");
}
return userJID;
}
/**
* 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<String> mechanisms) {
this.serverMechanisms = mechanisms;
}
/**
* Returns true if the user was able to authenticate with the server usins SASL.
*
* @return true if the user was able to authenticate with the server usins SASL.
*/
public boolean isAuthenticated() {
return saslNegotiated;
}
/**
* 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() {
synchronized (this) {
saslNegotiated = true;
// Wake up the thread that is waiting in the #authenticate method
notify();
}
}
/**
* Notification message saying that SASL authentication has failed. The server may have
* closed the connection depending on the number of possible retries.
*/
void authenticationFailed() {
synchronized (this) {
saslFailed = true;
// 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) {
resourceBinded = true;
// 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;
}
}