001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.net.imap;
019
020import java.io.IOException;
021import java.security.InvalidKeyException;
022import java.security.NoSuchAlgorithmException;
023import java.security.spec.InvalidKeySpecException;
024
025import javax.crypto.Mac;
026import javax.crypto.spec.SecretKeySpec;
027import javax.net.ssl.SSLContext;
028import org.apache.commons.net.util.Base64;
029
030/**
031 * An IMAP Client class with authentication support.
032 * @see IMAPSClient
033 */
034public class AuthenticatingIMAPClient extends IMAPSClient
035{
036    /**
037     * Constructor for AuthenticatingIMAPClient that delegates to IMAPSClient.
038     * Sets security mode to explicit (isImplicit = false).
039     */
040    public AuthenticatingIMAPClient()
041    {
042        this(DEFAULT_PROTOCOL, false);
043    }
044
045    /**
046     * Constructor for AuthenticatingIMAPClient that delegates to IMAPSClient.
047     * @param implicit The security mode (Implicit/Explicit).
048     */
049    public AuthenticatingIMAPClient(boolean implicit)
050    {
051        this(DEFAULT_PROTOCOL, implicit);
052    }
053
054    /**
055     * Constructor for AuthenticatingIMAPClient that delegates to IMAPSClient.
056     * @param proto the protocol.
057     */
058    public AuthenticatingIMAPClient(String proto)
059    {
060        this(proto, false);
061    }
062
063    /**
064     * Constructor for AuthenticatingIMAPClient that delegates to IMAPSClient.
065     * @param proto the protocol.
066     * @param implicit The security mode(Implicit/Explicit).
067     */
068    public AuthenticatingIMAPClient(String proto, boolean implicit)
069    {
070        this(proto, implicit, null);
071    }
072
073    /**
074     * Constructor for AuthenticatingIMAPClient that delegates to IMAPSClient.
075     * @param proto the protocol.
076     * @param implicit The security mode(Implicit/Explicit).
077     */
078    public AuthenticatingIMAPClient(String proto, boolean implicit, SSLContext ctx)
079    {
080        super(proto, implicit, ctx);
081    }
082
083    /**
084     * Constructor for AuthenticatingIMAPClient that delegates to IMAPSClient.
085     * @param implicit The security mode(Implicit/Explicit).
086     * @param ctx A pre-configured SSL Context.
087     */
088    public AuthenticatingIMAPClient(boolean implicit, SSLContext ctx)
089    {
090        this(DEFAULT_PROTOCOL, implicit, ctx);
091    }
092
093    /**
094     * Constructor for AuthenticatingIMAPClient that delegates to IMAPSClient.
095     * @param context A pre-configured SSL Context.
096     */
097    public AuthenticatingIMAPClient(SSLContext context)
098    {
099        this(false, context);
100    }
101
102    /**
103     * Authenticate to the IMAP server by sending the AUTHENTICATE command with the
104     * selected mechanism, using the given username and the given password.
105     * <p>
106     * @return True if successfully completed, false if not.
107     * @exception IOException  If an I/O error occurs while either sending a
108     *      command to the server or receiving a reply from the server.
109     * @exception NoSuchAlgorithmException If the CRAM hash algorithm
110     *      cannot be instantiated by the Java runtime system.
111     * @exception InvalidKeyException If the CRAM hash algorithm
112     *      failed to use the given password.
113     * @exception InvalidKeySpecException If the CRAM hash algorithm
114     *      failed to use the given password.
115     */
116    public boolean authenticate(AuthenticatingIMAPClient.AUTH_METHOD method,
117                        String username, String password)
118                        throws IOException, NoSuchAlgorithmException,
119                        InvalidKeyException, InvalidKeySpecException
120    {
121        return auth(method, username, password);
122    }
123
124    /**
125     * Authenticate to the IMAP server by sending the AUTHENTICATE command with the
126     * selected mechanism, using the given username and the given password.
127     * <p>
128     * @return True if successfully completed, false if not.
129     * @exception IOException  If an I/O error occurs while either sending a
130     *      command to the server or receiving a reply from the server.
131     * @exception NoSuchAlgorithmException If the CRAM hash algorithm
132     *      cannot be instantiated by the Java runtime system.
133     * @exception InvalidKeyException If the CRAM hash algorithm
134     *      failed to use the given password.
135     * @exception InvalidKeySpecException If the CRAM hash algorithm
136     *      failed to use the given password.
137     */
138    public boolean auth(AuthenticatingIMAPClient.AUTH_METHOD method,
139                        String username, String password)
140                        throws IOException, NoSuchAlgorithmException,
141                        InvalidKeyException, InvalidKeySpecException
142    {
143        if (!IMAPReply.isContinuation(sendCommand(IMAPCommand.AUTHENTICATE, method.getAuthName())))
144        {
145            return false;
146        }
147
148        switch (method) {
149            case PLAIN:
150            {
151                // the server sends an empty response ("+ "), so we don't have to read it.
152                int result = sendData(
153                    new String(
154                        Base64.encodeBase64(("\000" + username + "\000" + password).getBytes())
155                        )
156                    );
157                if (result == IMAPReply.OK)
158                {
159                    setState(IMAP.IMAPState.AUTH_STATE);
160                }
161                return result == IMAPReply.OK;
162            }
163            case CRAM_MD5:
164            {
165                // get the CRAM challenge (after "+ ")
166                byte[] serverChallenge = Base64.decodeBase64(getReplyString().substring(2).trim());
167                // get the Mac instance
168                Mac hmac_md5 = Mac.getInstance("HmacMD5");
169                hmac_md5.init(new SecretKeySpec(password.getBytes(), "HmacMD5"));
170                // compute the result:
171                byte[] hmacResult = _convertToHexString(hmac_md5.doFinal(serverChallenge)).getBytes();
172                // join the byte arrays to form the reply
173                byte[] usernameBytes = username.getBytes();
174                byte[] toEncode = new byte[usernameBytes.length + 1 /* the space */ + hmacResult.length];
175                System.arraycopy(usernameBytes, 0, toEncode, 0, usernameBytes.length);
176                toEncode[usernameBytes.length] = ' ';
177                System.arraycopy(hmacResult, 0, toEncode, usernameBytes.length + 1, hmacResult.length);
178                // send the reply and read the server code:
179                int result = sendData(new String(Base64.encodeBase64(toEncode)));
180                if (result == IMAPReply.OK)
181                {
182                    setState(IMAP.IMAPState.AUTH_STATE);
183                }
184                return result == IMAPReply.OK;
185            }
186            case LOGIN:
187            {
188                // the server sends fixed responses (base64("Username") and
189                // base64("Password")), so we don't have to read them.
190                if (sendData(
191                    new String(Base64.encodeBase64(username.getBytes()))) != IMAPReply.CONT)
192                {
193                    return false;
194                }
195                int result = sendData(
196                    new String(Base64.encodeBase64(password.getBytes())));
197                if (result == IMAPReply.OK)
198                {
199                    setState(IMAP.IMAPState.AUTH_STATE);
200                }
201                return result == IMAPReply.OK;
202            }
203        }
204        return false; // safety check
205    }
206
207    /**
208     * Converts the given byte array to a String containing the hex values of the bytes.
209     * For example, the byte 'A' will be converted to '41', because this is the ASCII code
210     * (and the byte value) of the capital letter 'A'.
211     * @param a The byte array to convert.
212     * @return The resulting String of hex codes.
213     */
214    private String _convertToHexString(byte[] a)
215    {
216        StringBuilder result = new StringBuilder(a.length*2);
217        for (int i = 0; i < a.length; i++)
218        {
219            if ( (a[i] & 0x0FF) <= 15 ) {
220                result.append("0");
221            }
222            result.append(Integer.toHexString(a[i] & 0x0FF));
223        }
224        return result.toString();
225    }
226
227    /**
228     * The enumeration of currently-supported authentication methods.
229     */
230    public static enum AUTH_METHOD
231    {
232        /** The standarised (RFC4616) PLAIN method, which sends the password unencrypted (insecure). */
233        PLAIN("PLAIN"),
234        /** The standarised (RFC2195) CRAM-MD5 method, which doesn't send the password (secure). */
235        CRAM_MD5("CRAM-MD5"),
236        /** The unstandarised Microsoft LOGIN method, which sends the password unencrypted (insecure). */
237        LOGIN("LOGIN");
238
239        private final String authName;
240        
241        private AUTH_METHOD(String name){
242            this.authName=name;
243        }
244        /**
245         * Gets the name of the given authentication method suitable for the server.
246         * @return The name of the given authentication method suitable for the server.
247         */
248        public final String getAuthName()
249        {
250            return authName;
251        }
252    }
253}
254/* kate: indent-width 4; replace-tabs on; */