Initial version. SMACK-24

git-svn-id: http://svn.igniterealtime.org/svn/repos/smack/trunk@2724 b35dd754-fafc-0310-a699-88a17e54d16e

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

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+/**
+ * $RCSfile$
+ * $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.sasl;
+
+import org.jivesoftware.smack.SASLAuthentication;
+import org.jivesoftware.smack.util.StringUtils;
+
+import java.io.IOException;
+
+/**
+ * Base class for SASL mechanisms. Subclasses must implement three methods:
+ * <ul>
+ *  <li>{@link #getName()} -- returns the common name of the SASL mechanism.</li>
+ *  <li>{@link #getAuthenticationText(String, String, String)} -- authentication text to include
+ *      in the initial <tt>auth</tt> stanza.</li>
+ *  <li>{@link #getChallengeResponse(byte[])} -- to respond challenges made by the server.</li>
+ * </ul>
+ *
+ * @author Gaston Dombiak
+ */
+public abstract class SASLMechanism {
+
+    private SASLAuthentication saslAuthentication;
+
+    public SASLMechanism(SASLAuthentication saslAuthentication) {
+        super();
+        this.saslAuthentication = saslAuthentication;
+    }
+
+    /**
+     * Builds and sends the <tt>auth</tt> stanza to the server.
+     *
+     * @param username the username of the user being authenticated.
+     * @param host     the hostname where the user account resides.
+     * @param password the password of the user.
+     * @throws IOException If a network error occures while authenticating.
+     */
+    public void authenticate(String username, String host, String password) throws IOException {
+        // Build the authentication stanza encoding the authentication text
+        StringBuffer stanza = new StringBuffer();
+        stanza.append("<auth mechanism=\"").append(getName());
+        stanza.append("\" xmlns=\"urn:ietf:params:xml:ns:xmpp-sasl\">");
+        String authenticationText = getAuthenticationText(username, host, password);
+        if (authenticationText != null) {
+            stanza.append(StringUtils.encodeBase64(authenticationText));
+        }
+        stanza.append("</auth>");
+
+        // Send the authentication to the server
+        getSASLAuthentication().send(stanza.toString());
+    }
+
+    /**
+     * 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.
+     */
+    public void challengeReceived(String challenge) throws IOException {
+        // Build the challenge response stanza encoding the response text
+        StringBuffer stanza = new StringBuffer();
+        stanza.append("<response xmlns=\"urn:ietf:params:xml:ns:xmpp-sasl\">");
+        String authenticationText = getChallengeResponse(StringUtils.decodeBase64(challenge));
+        stanza.append(StringUtils.encodeBase64(authenticationText));
+        stanza.append("</response>");
+
+        // Send the authentication to the server
+        getSASLAuthentication().send(stanza.toString());
+    }
+
+    /**
+     * Returns the response text to send answering the challenge sent by the server. Mechanisms
+     * that will never receive a challenge may redefine this method returning <tt>null</tt>.
+     *
+     * @param bytes the challenge sent by the server.
+     * @return the response text to send to answer the challenge sent by the server.
+     */
+    protected abstract String getChallengeResponse(byte[] bytes);
+
+    /**
+     * Returns the common name of the SASL mechanism. E.g.: PLAIN, DIGEST-MD5 or KERBEROS_V4.
+     *
+     * @return the common name of the SASL mechanism.
+     */
+    protected abstract String getName();
+
+    /**
+     * Returns the authentication text to include in the initial <tt>auth</tt> stanza
+     * or <tt>null</tt> if nothing should be added.
+     *
+     * @param username the username of the user being authenticated.
+     * @param host     the hostname where the user account resides.
+     * @param password the password of the user.
+     * @return the authentication text to include in the initial <tt>auth</tt> stanza
+     *         or <tt>null</tt> if nothing should be added.
+     */
+    protected abstract String getAuthenticationText(String username, String host, String password);
+
+    protected SASLAuthentication getSASLAuthentication() {
+        return saslAuthentication;
+    }
+}

source/org/jivesoftware/smack/sasl/SASLPlainMechanism.java

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+/**
+ * $RCSfile$
+ * $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.sasl;
+
+import org.jivesoftware.smack.SASLAuthentication;
+
+/**
+ * Implementation of the SASL PLAIN mechanisn as defined by the
+ * <a href="http://www.ietf.org/internet-drafts/draft-ietf-sasl-plain-08.txt">IETF draft
+ * document</a>.
+ *
+ * @author Gaston Dombiak
+ */
+public class SASLPlainMechanism extends SASLMechanism {
+
+    public SASLPlainMechanism(SASLAuthentication saslAuthentication) {
+        super(saslAuthentication);
+    }
+
+    protected String getName() {
+        return "PLAIN";
+    }
+
+    protected String getAuthenticationText(String username, String host, String password) {
+        // Build the text containing the "authorization identity" + NUL char +
+        // "authentication identity" + NUL char + "clear-text password"
+        StringBuffer text = new StringBuffer();
+        text.append(username).append("@").append(host);
+        text.append('\0');
+        text.append(username);
+        text.append('\0');
+        text.append(password);
+        return text.toString();
+    }
+
+    protected String getChallengeResponse(byte[] bytes) {
+        // Return null since this mechanism will never get a challenge from the server
+        return null;
+    }
+}