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Smack/source/org/jivesoftware/smack/sasl/SASLMechanism.java

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16 KiB
Java

/**
* $RCSfile$
* $Revision$
* $Date$
*
* Copyright 2003-2007 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.sasl;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.SASLAuthentication;
import org.jivesoftware.smack.packet.Packet;
import org.jivesoftware.smack.util.StringUtils;
import java.io.IOException;
import java.util.Map;
import java.util.HashMap;
import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.callback.UnsupportedCallbackException;
import javax.security.auth.callback.Callback;
import javax.security.auth.callback.NameCallback;
import javax.security.auth.callback.PasswordCallback;
import javax.security.sasl.RealmCallback;
import javax.security.sasl.RealmChoiceCallback;
import javax.security.sasl.Sasl;
import javax.security.sasl.SaslClient;
import javax.security.sasl.SaslException;
/**
* Base class for SASL mechanisms. Subclasses must implement these methods:
* <ul>
* <li>{@link #getName()} -- returns the common name of the SASL mechanism.</li>
* </ul>
* Subclasses will likely want to implement their own versions of these mthods:
* <li>{@link #authenticate(String, String, String)} -- Initiate authentication stanza using the
* deprecated method.</li>
* <li>{@link #authenticate(String, String, CallbackHandler)} -- Initiate authentication stanza
* using the CallbackHandler method.</li>
* <li>{@link #challengeReceived(String)} -- Handle a challenge from the server.</li>
* </ul>
*
* Basic XMPP SASL authentication steps:
* 1. Client authentication initialization, stanza sent to the server (Base64 encoded):
* <auth xmlns='urn:ietf:params:xml:ns:xmpp-sasl' mechanism='DIGEST-MD5'/>
* 2. Server sends back to the client the challenge response (Base64 encoded)
* sample:
* realm=<sasl server realm>,nonce="OA6MG9tEQGm2hh",qop="auth",charset=utf-8,algorithm=md5-sess
* 3. The client responds back to the server (Base 64 encoded):
* sample:
* username=<userid>,realm=<sasl server realm from above>,nonce="OA6MG9tEQGm2hh",
* cnonce="OA6MHXh6VqTrRk",nc=00000001,qop=auth,
* digest-uri=<digesturi>,
* response=d388dad90d4bbd760a152321f2143af7,
* charset=utf-8,
* authzid=<id>
* 4. The server evaluates if the user is present and contained in the REALM
* if successful it sends: <response xmlns='urn:ietf:params:xml:ns:xmpp-sasl'/> (Base64 encoded)
* if not successful it sends:
* sample:
* <challenge xmlns='urn:ietf:params:xml:ns:xmpp-sasl'>
* cnNwYXV0aD1lYTQwZjYwMzM1YzQyN2I1NTI3Yjg0ZGJhYmNkZmZmZA==
* </challenge>
*
*
* @author Jay Kline
*/
public abstract class SASLMechanism implements CallbackHandler {
private SASLAuthentication saslAuthentication;
protected SaslClient sc;
protected String authenticationId;
protected String password;
protected String hostname;
public SASLMechanism(SASLAuthentication saslAuthentication) {
this.saslAuthentication = saslAuthentication;
}
/**
* Builds and sends the <tt>auth</tt> stanza to the server. Note that this method of
* authentication is not recommended, since it is very inflexable. Use
* {@link #authenticate(String, String, CallbackHandler)} whenever possible.
*
* Explanation of auth stanza:
*
* The client authentication stanza needs to include the digest-uri of the form: xmpp/serverName
* From RFC-2831:
* digest-uri = "digest-uri" "=" digest-uri-value
* digest-uri-value = serv-type "/" host [ "/" serv-name ]
*
* digest-uri:
* Indicates the principal name of the service with which the client
* wishes to connect, formed from the serv-type, host, and serv-name.
* For example, the FTP service
* on "ftp.example.com" would have a "digest-uri" value of "ftp/ftp.example.com"; the SMTP
* server from the example above would have a "digest-uri" value of
* "smtp/mail3.example.com/example.com".
*
* host:
* The DNS host name or IP address for the service requested. The DNS host name
* must be the fully-qualified canonical name of the host. The DNS host name is the
* preferred form; see notes on server processing of the digest-uri.
*
* serv-name:
* Indicates the name of the service if it is replicated. The service is
* considered to be replicated if the client's service-location process involves resolution
* using standard DNS lookup operations, and if these operations involve DNS records (such
* as SRV, or MX) which resolve one DNS name into a set of other DNS names. In this case,
* the initial name used by the client is the "serv-name", and the final name is the "host"
* component. For example, the incoming mail service for "example.com" may be replicated
* through the use of MX records stored in the DNS, one of which points at an SMTP server
* called "mail3.example.com"; it's "serv-name" would be "example.com", it's "host" would be
* "mail3.example.com". If the service is not replicated, or the serv-name is identical to
* the host, then the serv-name component MUST be omitted
*
* digest-uri verification is needed for ejabberd 2.0.3 and higher
*
* @param username the username of the user being authenticated.
* @param host the hostname where the user account resides.
* @param serviceName the xmpp service location - used by the SASL client in digest-uri creation
* serviceName format is: host [ "/" serv-name ] as per RFC-2831
* @param password the password for this account.
* @throws IOException If a network error occurs while authenticating.
* @throws XMPPException If a protocol error occurs or the user is not authenticated.
*/
public void authenticate(String username, String host, String serviceName, String password) throws IOException, XMPPException {
//Since we were not provided with a CallbackHandler, we will use our own with the given
//information
//Set the authenticationID as the username, since they must be the same in this case.
this.authenticationId = username;
this.password = password;
this.hostname = host;
String[] mechanisms = { getName() };
Map<String,String> props = new HashMap<String,String>();
sc = Sasl.createSaslClient(mechanisms, username, "xmpp", serviceName, props, this);
authenticate();
}
/**
* Same as {@link #authenticate(String, String, String, String)}, but with the hostname used as the serviceName.
* <p>
* Kept for backward compatibility only.
*
* @param username the username of the user being authenticated.
* @param host the hostname where the user account resides.
* @param password the password for this account.
* @throws IOException If a network error occurs while authenticating.
* @throws XMPPException If a protocol error occurs or the user is not authenticated.
* @deprecated Please use {@link #authenticate(String, String, String, String)} instead.
*/
public void authenticate(String username, String host, String password) throws IOException, XMPPException {
authenticate(username, host, host, password);
}
/**
* Builds and sends the <tt>auth</tt> stanza to the server. The callback handler will handle
* any additional information, such as the authentication ID or realm, if it is needed.
*
* @param username the username of the user being authenticated.
* @param host the hostname where the user account resides.
* @param cbh the CallbackHandler to obtain user information.
* @throws IOException If a network error occures while authenticating.
* @throws XMPPException If a protocol error occurs or the user is not authenticated.
*/
public void authenticate(String username, String host, CallbackHandler cbh) throws IOException, XMPPException {
String[] mechanisms = { getName() };
Map<String,String> props = new HashMap<String,String>();
sc = Sasl.createSaslClient(mechanisms, username, "xmpp", host, props, cbh);
authenticate();
}
protected void authenticate() throws IOException, XMPPException {
String authenticationText = null;
try {
if(sc.hasInitialResponse()) {
byte[] response = sc.evaluateChallenge(new byte[0]);
authenticationText = StringUtils.encodeBase64(response, false);
}
} catch (SaslException e) {
throw new XMPPException("SASL authentication failed", e);
}
// Send the authentication to the server
getSASLAuthentication().send(new AuthMechanism(getName(), authenticationText));
}
/**
* The server is challenging the SASL mechanism for the stanza he just sent. Send a
* response to the server's challenge.
*
* @param challenge a base64 encoded string representing the challenge.
* @throws IOException if an exception sending the response occurs.
*/
public void challengeReceived(String challenge) throws IOException {
byte response[];
if(challenge != null) {
response = sc.evaluateChallenge(StringUtils.decodeBase64(challenge));
} else {
response = sc.evaluateChallenge(new byte[0]);
}
Packet responseStanza;
if (response == null) {
responseStanza = new Response();
}
else {
responseStanza = new Response(StringUtils.encodeBase64(response, false));
}
// Send the authentication to the server
getSASLAuthentication().send(responseStanza);
}
/**
* Returns the common name of the SASL mechanism. E.g.: PLAIN, DIGEST-MD5 or GSSAPI.
*
* @return the common name of the SASL mechanism.
*/
protected abstract String getName();
protected SASLAuthentication getSASLAuthentication() {
return saslAuthentication;
}
/**
*
*/
public void handle(Callback[] callbacks) throws IOException, UnsupportedCallbackException {
for (int i = 0; i < callbacks.length; i++) {
if (callbacks[i] instanceof NameCallback) {
NameCallback ncb = (NameCallback)callbacks[i];
ncb.setName(authenticationId);
} else if(callbacks[i] instanceof PasswordCallback) {
PasswordCallback pcb = (PasswordCallback)callbacks[i];
pcb.setPassword(password.toCharArray());
} else if(callbacks[i] instanceof RealmCallback) {
RealmCallback rcb = (RealmCallback)callbacks[i];
//Retrieve the REALM from the challenge response that the server returned when the client initiated the authentication
//exchange. If this value is not null or empty, *this value* has to be sent back to the server in the client's response
//to the server's challenge
String text = rcb.getDefaultText();
//The SASL client (sc) created in smack uses rcb.getText when creating the negotiatedRealm to send it back to the server
//Make sure that this value matches the server's realm
rcb.setText(text);
} else if(callbacks[i] instanceof RealmChoiceCallback){
//unused
//RealmChoiceCallback rccb = (RealmChoiceCallback)callbacks[i];
} else {
throw new UnsupportedCallbackException(callbacks[i]);
}
}
}
/**
* Initiating SASL authentication by select a mechanism.
*/
public class AuthMechanism extends Packet {
final private String name;
final private String authenticationText;
public AuthMechanism(String name, String authenticationText) {
if (name == null) {
throw new NullPointerException("SASL mechanism name shouldn't be null.");
}
this.name = name;
this.authenticationText = authenticationText;
}
public String toXML() {
StringBuilder stanza = new StringBuilder();
stanza.append("<auth mechanism=\"").append(name);
stanza.append("\" xmlns=\"urn:ietf:params:xml:ns:xmpp-sasl\">");
if (authenticationText != null &&
authenticationText.trim().length() > 0) {
stanza.append(authenticationText);
}
stanza.append("</auth>");
return stanza.toString();
}
}
/**
* A SASL challenge stanza.
*/
public static class Challenge extends Packet {
final private String data;
public Challenge(String data) {
this.data = data;
}
public String toXML() {
StringBuilder stanza = new StringBuilder();
stanza.append("<challenge xmlns=\"urn:ietf:params:xml:ns:xmpp-sasl\">");
if (data != null &&
data.trim().length() > 0) {
stanza.append(data);
}
stanza.append("</challenge>");
return stanza.toString();
}
}
/**
* A SASL response stanza.
*/
public class Response extends Packet {
final private String authenticationText;
public Response() {
authenticationText = null;
}
public Response(String authenticationText) {
if (authenticationText == null || authenticationText.trim().length() == 0) {
this.authenticationText = null;
}
else {
this.authenticationText = authenticationText;
}
}
public String toXML() {
StringBuilder stanza = new StringBuilder();
stanza.append("<response xmlns=\"urn:ietf:params:xml:ns:xmpp-sasl\">");
if (authenticationText != null) {
stanza.append(authenticationText);
}
stanza.append("</response>");
return stanza.toString();
}
}
/**
* A SASL success stanza.
*/
public static class Success extends Packet {
final private String data;
public Success(String data) {
this.data = data;
}
public String toXML() {
StringBuilder stanza = new StringBuilder();
stanza.append("<success xmlns=\"urn:ietf:params:xml:ns:xmpp-sasl\">");
if (data != null &&
data.trim().length() > 0) {
stanza.append(data);
}
stanza.append("</success>");
return stanza.toString();
}
}
/**
* A SASL failure stanza.
*/
public static class Failure extends Packet {
final private String condition;
public Failure(String condition) {
this.condition = condition;
}
/**
* Get the SASL related error condition.
*
* @return the SASL related error condition.
*/
public String getCondition() {
return condition;
}
public String toXML() {
StringBuilder stanza = new StringBuilder();
stanza.append("<failure xmlns=\"urn:ietf:params:xml:ns:xmpp-sasl\">");
if (condition != null &&
condition.trim().length() > 0) {
stanza.append("<").append(condition).append("/>");
}
stanza.append("</failure>");
return stanza.toString();
}
}
}