1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.net.pop3;
19
20 import java.io.IOException;
21 import java.security.InvalidKeyException;
22 import java.security.NoSuchAlgorithmException;
23 import java.security.spec.InvalidKeySpecException;
24 import javax.crypto.Mac;
25 import javax.crypto.spec.SecretKeySpec;
26
27 import org.apache.commons.net.util.Base64;
28
29
30 /**
31 * A POP3 Cilent class with protocol and authentication extensions support
32 * (RFC2449 and RFC2195).
33 * @see POP3Client
34 * @since 3.0
35 */
36 public class ExtendedPOP3Client extends POP3SClient
37 {
38 /**
39 * The default ExtendedPOP3Client constructor.
40 * Creates a new Extended POP3 Client.
41 * @throws NoSuchAlgorithmException
42 */
43 public ExtendedPOP3Client() throws NoSuchAlgorithmException
44 {
45 super();
46 }
47
48 /***
49 * Authenticate to the POP3 server by sending the AUTH command with the
50 * selected mechanism, using the given username and the given password.
51 * <p>
52 * @param method the {@link AUTH_METHOD} to use
53 * @param username the user name
54 * @param password the password
55 * @return True if successfully completed, false if not.
56 * @exception IOException If an I/O error occurs while either sending a
57 * command to the server or receiving a reply from the server.
58 * @exception NoSuchAlgorithmException If the CRAM hash algorithm
59 * cannot be instantiated by the Java runtime system.
60 * @exception InvalidKeyException If the CRAM hash algorithm
61 * failed to use the given password.
62 * @exception InvalidKeySpecException If the CRAM hash algorithm
63 * failed to use the given password.
64 ***/
65 public boolean auth(AUTH_METHOD method,
66 String username, String password)
67 throws IOException, NoSuchAlgorithmException,
68 InvalidKeyException, InvalidKeySpecException
69 {
70 if (sendCommand(POP3Command.AUTH, method.getAuthName())
71 != POP3Reply.OK_INT) {
72 return false;
73 }
74
75 switch(method) {
76 case PLAIN:
77 // the server sends an empty response ("+ "), so we don't have to read it.
78 return sendCommand(
79 new String(
80 Base64.encodeBase64(("\000" + username + "\000" + password).getBytes(this.getCharset())),
81 this.getCharset())
82 ) == POP3Reply.OK;
83 case CRAM_MD5:
84 // get the CRAM challenge
85 byte[] serverChallenge = Base64.decodeBase64(getReplyString().substring(2).trim());
86 // get the Mac instance
87 Mac hmac_md5 = Mac.getInstance("HmacMD5");
88 hmac_md5.init(new SecretKeySpec(password.getBytes(this.getCharset()), "HmacMD5"));
89 // compute the result:
90 byte[] hmacResult = _convertToHexString(hmac_md5.doFinal(serverChallenge)).getBytes(this.getCharset());
91 // join the byte arrays to form the reply
92 byte[] usernameBytes = username.getBytes(this.getCharset());
93 byte[] toEncode = new byte[usernameBytes.length + 1 /* the space */ + hmacResult.length];
94 System.arraycopy(usernameBytes, 0, toEncode, 0, usernameBytes.length);
95 toEncode[usernameBytes.length] = ' ';
96 System.arraycopy(hmacResult, 0, toEncode, usernameBytes.length + 1, hmacResult.length);
97 // send the reply and read the server code:
98 return sendCommand(Base64.encodeBase64StringUnChunked(toEncode)) == POP3Reply.OK;
99 default:
100 return false;
101 }
102 }
103
104 /**
105 * Converts the given byte array to a String containing the hex values of the bytes.
106 * For example, the byte 'A' will be converted to '41', because this is the ASCII code
107 * (and the byte value) of the capital letter 'A'.
108 * @param a The byte array to convert.
109 * @return The resulting String of hex codes.
110 */
111 private String _convertToHexString(byte[] a)
112 {
113 StringBuilder result = new StringBuilder(a.length*2);
114 for (byte element : a)
115 {
116 if ( (element & 0x0FF) <= 15 ) {
117 result.append("0");
118 }
119 result.append(Integer.toHexString(element & 0x0FF));
120 }
121 return result.toString();
122 }
123
124 /**
125 * The enumeration of currently-supported authentication methods.
126 */
127 public static enum AUTH_METHOD
128 {
129 /** The standarised (RFC4616) PLAIN method, which sends the password unencrypted (insecure). */
130 PLAIN("PLAIN"),
131
132 /** The standarised (RFC2195) CRAM-MD5 method, which doesn't send the password (secure). */
133 CRAM_MD5("CRAM-MD5");
134
135 private final String methodName;
136
137 AUTH_METHOD(String methodName){
138 this.methodName = methodName;
139 }
140 /**
141 * Gets the name of the given authentication method suitable for the server.
142 * @return The name of the given authentication method suitable for the server.
143 */
144 public final String getAuthName()
145 {
146 return this.methodName;
147 }
148 }
149 }