Mercurial > 510Connectbot

comparison app/src/main/java/ch/ethz/ssh2/channel/RemoteX11AcceptThread.java @ 438:d29cce60f393

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
migrate from Eclipse to Android Studio
author Carl Byington <carl@five-ten-sg.com>
date Thu, 03 Dec 2015 11:23:55 -0800
parents src/ch/ethz/ssh2/channel/RemoteX11AcceptThread.java@071eccdff8ea
children
comparison
equal deleted inserted replaced
437:208b31032318 438:d29cce60f393
1 /*
2 * Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
3 * Please refer to the LICENSE.txt for licensing details.
4 */
5 package ch.ethz.ssh2.channel;
6
7 import java.io.IOException;
8 import java.io.InputStream;
9 import java.io.OutputStream;
10 import java.net.Socket;
11
12 import ch.ethz.ssh2.log.Logger;
13 import ch.ethz.ssh2.util.StringEncoder;
14
15 /**
16 * RemoteX11AcceptThread.
17 *
18 * @author Christian Plattner
19 * @version $Id: RemoteX11AcceptThread.java 119 2014-04-12 20:30:58Z dkocher@sudo.ch $
20 */
21 public class RemoteX11AcceptThread extends Thread {
22 private static final Logger log = Logger.getLogger(RemoteX11AcceptThread.class);
23
24 Channel c;
25
26 String remoteOriginatorAddress;
27 int remoteOriginatorPort;
28
29 Socket s;
30
31 public RemoteX11AcceptThread(Channel c, String remoteOriginatorAddress, int remoteOriginatorPort) {
32 this.c = c;
33 this.remoteOriginatorAddress = remoteOriginatorAddress;
34 this.remoteOriginatorPort = remoteOriginatorPort;
35 }
36
37 @Override
38 public void run() {
39 try {
40 /* Send Open Confirmation */
41 c.cm.sendOpenConfirmation(c);
42 /* Read startup packet from client */
43 OutputStream remote_os = c.getStdinStream();
44 InputStream remote_is = c.getStdoutStream();
45 /* The following code is based on the protocol description given in:
46 * Scheifler/Gettys,
47 * X Windows System: Core and Extension Protocols:
48 * X Version 11, Releases 6 and 6.1 ISBN 1-55558-148-X
49 * (from the ETH library - after being here for almost ten
50 * years one of the few books I borrowed... sad but true =)
51 */
52 /*
53 * Client startup:
54 *
55 * 1 0X42 MSB first/0x6c lSB first - byteorder
56 * 1 - unused
57 * 2 card16 - protocol-major-version
58 * 2 card16 - protocol-minor-version
59 * 2 n - lenght of authorization-protocol-name
60 * 2 d - lenght of authorization-protocol-data
61 * 2 - unused
62 * string8 - authorization-protocol-name
63 * p - unused, p=pad(n)
64 * string8 - authorization-protocol-data
65 * q - unused, q=pad(d)
66 *
67 * pad(X) = (4 - (X mod 4)) mod 4
68 *
69 * Server response:
70 *
71 * 1 (0 failed, 2 authenticate, 1 success)
72 * ...
73 *
74 */
75 /* Later on we will simply forward the first 6 header bytes to the "real" X11 server */
76 byte[] header = new byte[6];
77
78 if (remote_is.read(header) != 6)
79 throw new IOException("Unexpected EOF on X11 startup!");
80
81 if ((header[0] != 0x42) && (header[0] != 0x6c)) // 0x42 MSB first, 0x6C LSB first
82 throw new IOException("Unknown endian format in X11 message!");
83
84 /* Yes, I came up with this myself - shall I file an application for a patent? =) */
85 int idxMSB = (header[0] == 0x42) ? 0 : 1;
86 /* Read authorization data header */
87 byte[] auth_buff = new byte[6];
88
89 if (remote_is.read(auth_buff) != 6)
90 throw new IOException("Unexpected EOF on X11 startup!");
91
92 int authProtocolNameLength = ((auth_buff[idxMSB] & 0xff) << 8) | (auth_buff[1 - idxMSB] & 0xff);
93 int authProtocolDataLength = ((auth_buff[2 + idxMSB] & 0xff) << 8) | (auth_buff[3 - idxMSB] & 0xff);
94
95 if ((authProtocolNameLength > 256) || (authProtocolDataLength > 256))
96 throw new IOException("Buggy X11 authorization data");
97
98 int authProtocolNamePadding = ((4 - (authProtocolNameLength % 4)) % 4);
99 int authProtocolDataPadding = ((4 - (authProtocolDataLength % 4)) % 4);
100 byte[] authProtocolName = new byte[authProtocolNameLength];
101 byte[] authProtocolData = new byte[authProtocolDataLength];
102 byte[] paddingBuffer = new byte[4];
103
104 if (remote_is.read(authProtocolName) != authProtocolNameLength)
105 throw new IOException("Unexpected EOF on X11 startup! (authProtocolName)");
106
107 if (remote_is.read(paddingBuffer, 0, authProtocolNamePadding) != authProtocolNamePadding)
108 throw new IOException("Unexpected EOF on X11 startup! (authProtocolNamePadding)");
109
110 if (remote_is.read(authProtocolData) != authProtocolDataLength)
111 throw new IOException("Unexpected EOF on X11 startup! (authProtocolData)");
112
113 if (remote_is.read(paddingBuffer, 0, authProtocolDataPadding) != authProtocolDataPadding)
114 throw new IOException("Unexpected EOF on X11 startup! (authProtocolDataPadding)");
115
116 if ("MIT-MAGIC-COOKIE-1".equals(StringEncoder.GetString(authProtocolName)) == false)
117 throw new IOException("Unknown X11 authorization protocol!");
118
119 if (authProtocolDataLength != 16)
120 throw new IOException("Wrong data length for X11 authorization data!");
121
122 StringBuilder tmp = new StringBuilder(32);
123
124 for (int i = 0; i < authProtocolData.length; i++) {
125 String digit2 = Integer.toHexString(authProtocolData[i] & 0xff);
126 tmp.append((digit2.length() == 2) ? digit2 : "0" + digit2);
127 }
128
129 String hexEncodedFakeCookie = tmp.toString();
130
131 /* Order is very important here - it may be that a certain x11 forwarding
132 * gets disabled right in the moment when we check and register our connection
133 * */
134
135 synchronized (c) {
136 /* Please read the comment in Channel.java */
137 c.hexX11FakeCookie = hexEncodedFakeCookie;
138 }
139
140 /* Now check our fake cookie directory to see if we produced this cookie */
141 X11ServerData sd = c.cm.checkX11Cookie(hexEncodedFakeCookie);
142
143 if (sd == null)
144 throw new IOException("Invalid X11 cookie received.");
145
146 /* If the session which corresponds to this cookie is closed then we will
147 * detect this: the session's close code will close all channels
148 * with the session's assigned x11 fake cookie.
149 */
150 s = new Socket(sd.hostname, sd.port);
151 OutputStream x11_os = s.getOutputStream();
152 InputStream x11_is = s.getInputStream();
153 /* Now we are sending the startup packet to the real X11 server */
154 x11_os.write(header);
155
156 if (sd.x11_magic_cookie == null) {
157 byte[] emptyAuthData = new byte[6];
158 /* empty auth data, hopefully you are connecting to localhost =) */
159 x11_os.write(emptyAuthData);
160 }
161 else {
162 if (sd.x11_magic_cookie.length != 16)
163 throw new IOException("The real X11 cookie has an invalid length!");
164
165 /* send X11 cookie specified by client */
166 x11_os.write(auth_buff);
167 x11_os.write(authProtocolName); /* re-use */
168 x11_os.write(paddingBuffer, 0, authProtocolNamePadding);
169 x11_os.write(sd.x11_magic_cookie);
170 x11_os.write(paddingBuffer, 0, authProtocolDataPadding);
171 }
172
173 x11_os.flush();
174 /* Start forwarding traffic */
175 StreamForwarder r2l = new StreamForwarder(c, null, null, remote_is, x11_os, "RemoteToX11");
176 StreamForwarder l2r = new StreamForwarder(c, null, null, x11_is, remote_os, "X11ToRemote");
177 /* No need to start two threads, one can be executed in the current thread */
178 r2l.setDaemon(true);
179 r2l.start();
180 l2r.run();
181
182 while (r2l.isAlive()) {
183 try {
184 r2l.join();
185 }
186 catch (InterruptedException ignored) {
187 }
188 }
189
190 /* If the channel is already closed, then this is a no-op */
191 c.cm.closeChannel(c, "EOF on both X11 streams reached.", true);
192 s.close();
193 }
194 catch (IOException e) {
195 log.warning("IOException in X11 proxy code: " + e.getMessage());
196
197 try {
198 c.cm.closeChannel(c, e, true);
199 }
200 catch (IOException ignored) {
201 }
202
203 try {
204 if (s != null)
205 s.close();
206 }
207 catch (IOException ignored) {
208 }
209 }
210 }
211 }