1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
|
/**
* $RCSfile$
* $Revision$
* $Date$
*
* 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));
if (authenticationText != null) {
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;
}
}
|
