ObexSession.java revision 05ff98bbefda39b9ff26f8bca132cfd0248745c6 
1/*
2 * Copyright (c) 2008-2009, Motorola, Inc.
3 *
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * - Redistributions of source code must retain the above copyright notice,
10 * this list of conditions and the following disclaimer.
11 *
12 * - Redistributions in binary form must reproduce the above copyright notice,
13 * this list of conditions and the following disclaimer in the documentation
14 * and/or other materials provided with the distribution.
15 *
16 * - Neither the name of the Motorola, Inc. nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
21 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
24 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33package javax.obex;
34
35import java.io.IOException;
36
37/**
38 * The <code>ObexSession</code> interface characterizes the term
39 * "OBEX Connection" as defined in the IrDA Object Exchange Protocol v1.2, which
40 * could be the server-side view of an OBEX connection, or the client-side view
41 * of the same connection, which is established by server's accepting of a
42 * client issued "CONNECT".
43 * <P>
44 * This interface serves as the common super class for
45 * <CODE>ClientSession</CODE> and <CODE>ServerSession</CODE>.
46 * @hide
47 */
48public class ObexSession {
49
50    protected Authenticator mAuthenticator;
51
52    protected byte[] mChallengeDigest;
53
54    /**
55     * Called when the server received an authentication challenge header. This
56     * will cause the authenticator to handle the authentication challenge.
57     * @param header the header with the authentication challenge
58     * @return <code>true</code> if the last request should be resent;
59     *         <code>false</code> if the last request should not be resent
60     * @throws IOException
61     */
62    public boolean handleAuthChall(HeaderSet header) throws IOException {
63        if (mAuthenticator == null) {
64            return false;
65        }
66
67        /*
68         * An authentication challenge is made up of one required and two
69         * optional tag length value triplets. The tag 0x00 is required to be in
70         * the authentication challenge and it represents the challenge digest
71         * that was received. The tag 0x01 is the options tag. This tag tracks
72         * if user ID is required and if full access will be granted. The tag
73         * 0x02 is the realm, which provides a description of which user name
74         * and password to use.
75         */
76        byte[] challenge = ObexHelper.getTagValue((byte)0x00, header.mAuthChall);
77        byte[] option = ObexHelper.getTagValue((byte)0x01, header.mAuthChall);
78        byte[] description = ObexHelper.getTagValue((byte)0x02, header.mAuthChall);
79
80        String realm = null;
81        if (description != null) {
82            byte[] realmString = new byte[description.length - 1];
83            System.arraycopy(description, 1, realmString, 0, realmString.length);
84
85            switch (description[0] & 0xFF) {
86
87                case ObexHelper.OBEX_AUTH_REALM_CHARSET_ASCII:
88                    // ASCII encoding
89                    // Fall through
90                case ObexHelper.OBEX_AUTH_REALM_CHARSET_ISO_8859_1:
91                    // ISO-8859-1 encoding
92                    try {
93                        realm = new String(realmString, "ISO8859_1");
94                    } catch (Exception e) {
95                        throw new IOException("Unsupported Encoding Scheme");
96                    }
97                    break;
98
99                case ObexHelper.OBEX_AUTH_REALM_CHARSET_UNICODE:
100                    // UNICODE Encoding
101                    realm = ObexHelper.convertToUnicode(realmString, false);
102                    break;
103
104                default:
105                    throw new IOException("Unsupported Encoding Scheme");
106            }
107        }
108
109        boolean isUserIDRequired = false;
110        boolean isFullAccess = true;
111        if (option != null) {
112            if ((option[0] & 0x01) != 0) {
113                isUserIDRequired = true;
114            }
115
116            if ((option[0] & 0x02) != 0) {
117                isFullAccess = false;
118            }
119        }
120
121        PasswordAuthentication result = null;
122        header.mAuthChall = null;
123
124        try {
125            result = mAuthenticator
126                    .onAuthenticationChallenge(realm, isUserIDRequired, isFullAccess);
127        } catch (Exception e) {
128            return false;
129        }
130
131        /*
132         * If no password is provided then we not resent the request
133         */
134        if (result == null) {
135            return false;
136        }
137
138        byte[] password = result.getPassword();
139        if (password == null) {
140            return false;
141        }
142
143        byte[] userName = result.getUserName();
144
145        /*
146         * Create the authentication response header. It includes 1 required and
147         * 2 option tag length value triples. The required triple has a tag of
148         * 0x00 and is the response digest. The first optional tag is 0x01 and
149         * represents the user ID. If no user ID is provided, then no user ID
150         * will be sent. The second optional tag is 0x02 and is the challenge
151         * that was received. This will always be sent
152         */
153        if (userName != null) {
154            header.mAuthResp = new byte[38 + userName.length];
155            header.mAuthResp[36] = (byte)0x01;
156            header.mAuthResp[37] = (byte)userName.length;
157            System.arraycopy(userName, 0, header.mAuthResp, 38, userName.length);
158        } else {
159            header.mAuthResp = new byte[36];
160        }
161
162        // Create the secret String
163        byte[] digest = new byte[challenge.length + password.length + 1];
164        System.arraycopy(challenge, 0, digest, 0, challenge.length);
165        // Insert colon between challenge and password
166        digest[challenge.length] = (byte)0x3A;
167        System.arraycopy(password, 0, digest, challenge.length + 1, password.length);
168
169        // Add the Response Digest
170        header.mAuthResp[0] = (byte)0x00;
171        header.mAuthResp[1] = (byte)0x10;
172
173        System.arraycopy(ObexHelper.computeMd5Hash(digest), 0, header.mAuthResp, 2, 16);
174
175        // Add the challenge
176        header.mAuthResp[18] = (byte)0x02;
177        header.mAuthResp[19] = (byte)0x10;
178        System.arraycopy(challenge, 0, header.mAuthResp, 20, 16);
179
180        return true;
181    }
182
183    /**
184     * Called when the server received an authentication response header. This
185     * will cause the authenticator to handle the authentication response.
186     * @param authResp the authentication response
187     * @return <code>true</code> if the response passed; <code>false</code> if
188     *         the response failed
189     */
190    public boolean handleAuthResp(byte[] authResp) {
191        if (mAuthenticator == null) {
192            return false;
193        }
194        // get the correct password from the application
195        byte[] correctPassword = mAuthenticator.onAuthenticationResponse(ObexHelper.getTagValue(
196                (byte)0x01, authResp));
197        if (correctPassword == null) {
198            return false;
199        }
200
201        byte[] temp = new byte[correctPassword.length + 16];
202
203        System.arraycopy(mChallengeDigest, 0, temp, 0, 16);
204        System.arraycopy(correctPassword, 0, temp, 16, correctPassword.length);
205
206        byte[] correctResponse = ObexHelper.computeMd5Hash(temp);
207        byte[] actualResponse = ObexHelper.getTagValue((byte)0x00, authResp);
208
209        // compare the MD5 hash array .
210        for (int i = 0; i < 16; i++) {
211            if (correctResponse[i] != actualResponse[i]) {
212                return false;
213            }
214        }
215
216        return true;
217    }
218}
219