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comparison src/ch/ethz/ssh2/transport/TransportConnection.java @ 273:91a31873c42a ganymed

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start conversion from trilead to ganymed
author Carl Byington <carl@five-ten-sg.com>
date Fri, 18 Jul 2014 11:21:46 -0700
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children 071eccdff8ea
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272:ce2f4e397703 273:91a31873c42a
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.transport;
6
7 import java.io.IOException;
8 import java.io.InputStream;
9 import java.io.OutputStream;
10 import java.security.SecureRandom;
11
12 import ch.ethz.ssh2.PacketFormatException;
13 import ch.ethz.ssh2.compression.Compressor;
14 import ch.ethz.ssh2.crypto.cipher.BlockCipher;
15 import ch.ethz.ssh2.crypto.cipher.CipherInputStream;
16 import ch.ethz.ssh2.crypto.cipher.CipherOutputStream;
17 import ch.ethz.ssh2.crypto.cipher.NullCipher;
18 import ch.ethz.ssh2.crypto.digest.MAC;
19 import ch.ethz.ssh2.log.Logger;
20 import ch.ethz.ssh2.packets.Packets;
21
22 /**
23 * TransportConnection.
24 *
25 * @author Christian Plattner
26 * @version $Id: TransportConnection.java 144 2014-04-25 12:48:25Z dkocher@sudo.ch $
27 */
28 public class TransportConnection {
29 private static final Logger log = Logger.getLogger(TransportConnection.class);
30
31 int send_seq_number = 0;
32
33 int recv_seq_number = 0;
34
35 CipherInputStream cis;
36
37 CipherOutputStream cos;
38
39 boolean useRandomPadding;
40
41 /* Depends on current MAC and CIPHER */
42
43 MAC send_mac;
44
45 byte[] send_mac_buffer;
46
47 int send_padd_blocksize = 8;
48
49 MAC recv_mac;
50
51 byte[] recv_mac_buffer;
52
53 byte[] recv_mac_buffer_cmp;
54
55 int recv_padd_blocksize = 8;
56
57 Compressor recv_comp;
58
59 Compressor send_comp;
60
61 boolean can_compress;
62
63 byte[] recv_comp_buffer;
64
65 byte[] send_comp_buffer;
66
67 /* won't change */
68
69 final byte[] send_padding_buffer = new byte[256];
70
71 final byte[] send_packet_header_buffer = new byte[5];
72
73 final byte[] recv_padding_buffer = new byte[256];
74
75 final byte[] recv_packet_header_buffer = new byte[5];
76
77 boolean recv_packet_header_present = false;
78
79 ClientServerHello csh;
80
81 final SecureRandom rnd;
82
83 public TransportConnection(InputStream is, OutputStream os, SecureRandom rnd) {
84 this.cis = new CipherInputStream(new NullCipher(), is);
85 this.cos = new CipherOutputStream(new NullCipher(), os);
86 this.rnd = rnd;
87 }
88
89 public void changeRecvCipher(BlockCipher bc, MAC mac) {
90 cis.changeCipher(bc);
91 recv_mac = mac;
92 recv_mac_buffer = (mac != null) ? new byte[mac.size()] : null;
93 recv_mac_buffer_cmp = (mac != null) ? new byte[mac.size()] : null;
94 recv_padd_blocksize = bc.getBlockSize();
95 if(recv_padd_blocksize < 8) {
96 recv_padd_blocksize = 8;
97 }
98 }
99
100 public void changeSendCipher(BlockCipher bc, MAC mac) {
101 if((bc instanceof NullCipher) == false) {
102 /* Only use zero byte padding for the first few packets */
103 useRandomPadding = true;
104 /* Once we start encrypting, there is no way back */
105 }
106
107 cos.changeCipher(bc);
108 send_mac = mac;
109 send_mac_buffer = (mac != null) ? new byte[mac.size()] : null;
110 send_padd_blocksize = bc.getBlockSize();
111 if(send_padd_blocksize < 8) {
112 send_padd_blocksize = 8;
113 }
114 }
115
116 public void changeRecvCompression(Compressor comp) {
117 recv_comp = comp;
118
119 if(comp != null) {
120 recv_comp_buffer = new byte[comp.getBufferSize()];
121 }
122 }
123
124 public void changeSendCompression(Compressor comp) {
125 send_comp = comp;
126
127 if(comp != null) {
128 send_comp_buffer = new byte[comp.getBufferSize()];
129 }
130 }
131
132 public void sendMessage(byte[] message) throws IOException {
133 sendMessage(message, 0, message.length, 0);
134 }
135
136 public void sendMessage(byte[] message, int off, int len) throws IOException {
137 sendMessage(message, off, len, 0);
138 }
139
140 public int getPacketOverheadEstimate() {
141 // return an estimate for the paket overhead (for send operations)
142 return 5 + 4 + (send_padd_blocksize - 1) + send_mac_buffer.length;
143 }
144
145 public void sendMessage(byte[] message, int off, int len, int padd) throws IOException {
146 if(padd < 4) {
147 padd = 4;
148 }
149 else if(padd > 64) {
150 padd = 64;
151 }
152
153 if(send_comp != null && can_compress) {
154 len = send_comp.compress(message, off, len, send_comp_buffer);
155 message = send_comp_buffer;
156 }
157
158 int packet_len = 5 + len + padd; /* Minimum allowed padding is 4 */
159
160 int slack = packet_len % send_padd_blocksize;
161
162 if(slack != 0) {
163 packet_len += (send_padd_blocksize - slack);
164 }
165
166 if(packet_len < 16) {
167 packet_len = 16;
168 }
169
170 int padd_len = packet_len - (5 + len);
171
172 if(useRandomPadding) {
173 for(int i = 0; i < padd_len; i = i + 4) {
174 /*
175 * don't waste calls to rnd.nextInt() (by using only 8bit of the
176 * output). just believe me: even though we may write here up to 3
177 * bytes which won't be used, there is no "buffer overflow" (i.e.,
178 * arrayindexoutofbounds). the padding buffer is big enough =) (256
179 * bytes, and that is bigger than any current cipher block size + 64).
180 */
181
182 int r = rnd.nextInt();
183 send_padding_buffer[i] = (byte) r;
184 send_padding_buffer[i + 1] = (byte) (r >> 8);
185 send_padding_buffer[i + 2] = (byte) (r >> 16);
186 send_padding_buffer[i + 3] = (byte) (r >> 24);
187 }
188 }
189 else {
190 /* use zero padding for unencrypted traffic */
191 for(int i = 0; i < padd_len; i++) {
192 send_padding_buffer[i] = 0;
193 }
194 /* Actually this code is paranoid: we never filled any
195 * bytes into the padding buffer so far, therefore it should
196 * consist of zeros only.
197 */
198 }
199
200 send_packet_header_buffer[0] = (byte) ((packet_len - 4) >> 24);
201 send_packet_header_buffer[1] = (byte) ((packet_len - 4) >> 16);
202 send_packet_header_buffer[2] = (byte) ((packet_len - 4) >> 8);
203 send_packet_header_buffer[3] = (byte) ((packet_len - 4));
204 send_packet_header_buffer[4] = (byte) padd_len;
205
206 cos.write(send_packet_header_buffer, 0, 5);
207 cos.write(message, off, len);
208 cos.write(send_padding_buffer, 0, padd_len);
209
210 if(send_mac != null) {
211 send_mac.initMac(send_seq_number);
212 send_mac.update(send_packet_header_buffer, 0, 5);
213 send_mac.update(message, off, len);
214 send_mac.update(send_padding_buffer, 0, padd_len);
215
216 send_mac.getMac(send_mac_buffer, 0);
217 cos.writePlain(send_mac_buffer, 0, send_mac_buffer.length);
218 }
219
220 cos.flush();
221
222 if(log.isDebugEnabled()) {
223 log.debug("Sent " + Packets.getMessageName(message[off] & 0xff) + " " + len + " bytes payload");
224 }
225
226 send_seq_number++;
227 }
228
229 public int peekNextMessageLength() throws IOException {
230 if(recv_packet_header_present == false) {
231 cis.read(recv_packet_header_buffer, 0, 5);
232 recv_packet_header_present = true;
233 }
234
235 int packet_length = ((recv_packet_header_buffer[0] & 0xff) << 24)
236 | ((recv_packet_header_buffer[1] & 0xff) << 16) | ((recv_packet_header_buffer[2] & 0xff) << 8)
237 | ((recv_packet_header_buffer[3] & 0xff));
238
239 int padding_length = recv_packet_header_buffer[4] & 0xff;
240
241 if(packet_length > TransportManager.MAX_PACKET_SIZE || packet_length < 12) {
242 throw new PacketFormatException(String.format("Illegal packet size (%d)", packet_length));
243 }
244
245 int payload_length = packet_length - padding_length - 1;
246
247 if(payload_length < 0) {
248 throw new PacketFormatException(String.format("Illegal padding_length in packet from remote (%d)", padding_length));
249 }
250
251 return payload_length;
252 }
253
254 public int receiveMessage(byte buffer[], int off, int len) throws IOException {
255 if(recv_packet_header_present == false) {
256 cis.read(recv_packet_header_buffer, 0, 5);
257 }
258 else {
259 recv_packet_header_present = false;
260 }
261
262 int packet_length = ((recv_packet_header_buffer[0] & 0xff) << 24)
263 | ((recv_packet_header_buffer[1] & 0xff) << 16) | ((recv_packet_header_buffer[2] & 0xff) << 8)
264 | ((recv_packet_header_buffer[3] & 0xff));
265
266 int padding_length = recv_packet_header_buffer[4] & 0xff;
267
268 if(packet_length > TransportManager.MAX_PACKET_SIZE || packet_length < 12) {
269 throw new PacketFormatException(String.format("Illegal packet size (%d)", packet_length));
270 }
271
272 int payload_length = packet_length - padding_length - 1;
273
274 if(payload_length < 0) {
275 throw new PacketFormatException(String.format("Illegal padding_length in packet from remote (%d)", padding_length));
276 }
277
278 if(payload_length >= len) {
279 throw new IOException("Receive buffer too small (" + len + ", need " + payload_length + ")");
280 }
281
282 cis.read(buffer, off, payload_length);
283 cis.read(recv_padding_buffer, 0, padding_length);
284
285 if(recv_mac != null) {
286 cis.readPlain(recv_mac_buffer, 0, recv_mac_buffer.length);
287
288 recv_mac.initMac(recv_seq_number);
289 recv_mac.update(recv_packet_header_buffer, 0, 5);
290 recv_mac.update(buffer, off, payload_length);
291 recv_mac.update(recv_padding_buffer, 0, padding_length);
292 recv_mac.getMac(recv_mac_buffer_cmp, 0);
293
294 for(int i = 0; i < recv_mac_buffer.length; i++) {
295 if(recv_mac_buffer[i] != recv_mac_buffer_cmp[i]) {
296 throw new IOException("Remote sent corrupt MAC.");
297 }
298 }
299 }
300
301 recv_seq_number++;
302
303 if(log.isDebugEnabled()) {
304 log.debug("Received " + Packets.getMessageName(buffer[off] & 0xff) + " " + payload_length
305 + " bytes payload");
306 }
307
308 if(recv_comp != null && can_compress) {
309 int[] uncomp_len = new int[]{payload_length};
310 buffer = recv_comp.uncompress(buffer, off, uncomp_len);
311 return uncomp_len[0];
312 }
313 else {
314 return payload_length;
315 }
316 }
317
318 public void startCompression() {
319 can_compress = true;
320 }
321 }