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comparison src/com/trilead/ssh2/transport/KexManager.java @ 0:0ce5cc452d02

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initial version
author Carl Byington <carl@five-ten-sg.com>
date Thu, 22 May 2014 10:41:19 -0700
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1
2 package com.trilead.ssh2.transport;
3
4 import java.io.IOException;
5 import java.security.SecureRandom;
6 import java.security.interfaces.DSAPublicKey;
7 import java.security.interfaces.ECPublicKey;
8 import java.security.interfaces.RSAPublicKey;
9 import java.util.Set;
10 import java.util.TreeSet;
11
12 import com.trilead.ssh2.ConnectionInfo;
13 import com.trilead.ssh2.DHGexParameters;
14 import com.trilead.ssh2.ServerHostKeyVerifier;
15 import com.trilead.ssh2.compression.CompressionFactory;
16 import com.trilead.ssh2.compression.ICompressor;
17 import com.trilead.ssh2.crypto.CryptoWishList;
18 import com.trilead.ssh2.crypto.KeyMaterial;
19 import com.trilead.ssh2.crypto.cipher.BlockCipher;
20 import com.trilead.ssh2.crypto.cipher.BlockCipherFactory;
21 import com.trilead.ssh2.crypto.dh.DhGroupExchange;
22 import com.trilead.ssh2.crypto.dh.GenericDhExchange;
23 import com.trilead.ssh2.crypto.digest.MAC;
24 import com.trilead.ssh2.log.Logger;
25 import com.trilead.ssh2.packets.PacketKexDHInit;
26 import com.trilead.ssh2.packets.PacketKexDHReply;
27 import com.trilead.ssh2.packets.PacketKexDhGexGroup;
28 import com.trilead.ssh2.packets.PacketKexDhGexInit;
29 import com.trilead.ssh2.packets.PacketKexDhGexReply;
30 import com.trilead.ssh2.packets.PacketKexDhGexRequest;
31 import com.trilead.ssh2.packets.PacketKexDhGexRequestOld;
32 import com.trilead.ssh2.packets.PacketKexInit;
33 import com.trilead.ssh2.packets.PacketNewKeys;
34 import com.trilead.ssh2.packets.Packets;
35 import com.trilead.ssh2.signature.DSASHA1Verify;
36 import com.trilead.ssh2.signature.ECDSASHA2Verify;
37 import com.trilead.ssh2.signature.RSASHA1Verify;
38
39
40 /**
41 * KexManager.
42 *
43 * @author Christian Plattner, plattner@trilead.com
44 * @version $Id: KexManager.java,v 1.1 2007/10/15 12:49:56 cplattne Exp $
45 */
46 public class KexManager {
47 private static final Logger log = Logger.getLogger(KexManager.class);
48
49 private static final Set<String> HOSTKEY_ALGS = new TreeSet<String>();
50 static {
51 HOSTKEY_ALGS.add("ecdsa-sha2-nistp256");
52 HOSTKEY_ALGS.add("ecdsa-sha2-nistp384");
53 HOSTKEY_ALGS.add("ecdsa-sha2-nistp521");
54 HOSTKEY_ALGS.add("ssh-rsa");
55 HOSTKEY_ALGS.add("ssh-dsa");
56 }
57
58 private static final Set<String> KEX_ALGS = new TreeSet<String>();
59 static {
60 KEX_ALGS.add("ecdh-sha2-nistp256");
61 KEX_ALGS.add("ecdh-sha2-nistp384");
62 KEX_ALGS.add("ecdh-sha2-nistp521");
63 KEX_ALGS.add("diffie-hellman-group-exchange-sha256");
64 KEX_ALGS.add("diffie-hellman-group-exchange-sha1");
65 KEX_ALGS.add("diffie-hellman-group14-sha1");
66 KEX_ALGS.add("diffie-hellman-group1-sha1");
67 }
68
69 KexState kxs;
70 int kexCount = 0;
71 KeyMaterial km;
72 byte[] sessionId;
73 ClientServerHello csh;
74
75 final Object accessLock = new Object();
76 ConnectionInfo lastConnInfo = null;
77
78 boolean connectionClosed = false;
79
80 boolean ignore_next_kex_packet = false;
81
82 final TransportManager tm;
83
84 CryptoWishList nextKEXcryptoWishList;
85 DHGexParameters nextKEXdhgexParameters;
86
87 ServerHostKeyVerifier verifier;
88 final String hostname;
89 final int port;
90 final SecureRandom rnd;
91
92 public KexManager(TransportManager tm, ClientServerHello csh, CryptoWishList initialCwl, String hostname, int port,
93 ServerHostKeyVerifier keyVerifier, SecureRandom rnd) {
94 this.tm = tm;
95 this.csh = csh;
96 this.nextKEXcryptoWishList = initialCwl;
97 this.nextKEXdhgexParameters = new DHGexParameters();
98 this.hostname = hostname;
99 this.port = port;
100 this.verifier = keyVerifier;
101 this.rnd = rnd;
102 }
103
104 public ConnectionInfo getOrWaitForConnectionInfo(int minKexCount) throws IOException {
105 synchronized (accessLock) {
106 while (true) {
107 if ((lastConnInfo != null) && (lastConnInfo.keyExchangeCounter >= minKexCount))
108 return lastConnInfo;
109
110 if (connectionClosed)
111 throw(IOException) new IOException("Key exchange was not finished, connection is closed.")
112 .initCause(tm.getReasonClosedCause());
113
114 try {
115 accessLock.wait();
116 }
117 catch (InterruptedException e) {
118 }
119 }
120 }
121 }
122
123 private String getFirstMatch(String[] client, String[] server) throws NegotiateException {
124 if (client == null || server == null)
125 throw new IllegalArgumentException();
126
127 if (client.length == 0)
128 return null;
129
130 for (int i = 0; i < client.length; i++) {
131 for (int j = 0; j < server.length; j++) {
132 if (client[i].equals(server[j]))
133 return client[i];
134 }
135 }
136
137 throw new NegotiateException();
138 }
139
140 private boolean compareFirstOfNameList(String[] a, String[] b) {
141 if (a == null || b == null)
142 throw new IllegalArgumentException();
143
144 if ((a.length == 0) && (b.length == 0))
145 return true;
146
147 if ((a.length == 0) || (b.length == 0))
148 return false;
149
150 return (a[0].equals(b[0]));
151 }
152
153 private boolean isGuessOK(KexParameters cpar, KexParameters spar) {
154 if (cpar == null || spar == null)
155 throw new IllegalArgumentException();
156
157 if (compareFirstOfNameList(cpar.kex_algorithms, spar.kex_algorithms) == false) {
158 return false;
159 }
160
161 if (compareFirstOfNameList(cpar.server_host_key_algorithms, spar.server_host_key_algorithms) == false) {
162 return false;
163 }
164
165 /*
166 * We do NOT check here if the other algorithms can be agreed on, this
167 * is just a check if kex_algorithms and server_host_key_algorithms were
168 * guessed right!
169 */
170 return true;
171 }
172
173 private NegotiatedParameters mergeKexParameters(KexParameters client, KexParameters server) {
174 NegotiatedParameters np = new NegotiatedParameters();
175
176 try {
177 np.kex_algo = getFirstMatch(client.kex_algorithms, server.kex_algorithms);
178 log.log(20, "kex_algo=" + np.kex_algo);
179 np.server_host_key_algo = getFirstMatch(client.server_host_key_algorithms,
180 server.server_host_key_algorithms);
181 log.log(20, "server_host_key_algo=" + np.server_host_key_algo);
182 np.enc_algo_client_to_server = getFirstMatch(client.encryption_algorithms_client_to_server,
183 server.encryption_algorithms_client_to_server);
184 np.enc_algo_server_to_client = getFirstMatch(client.encryption_algorithms_server_to_client,
185 server.encryption_algorithms_server_to_client);
186 log.log(20, "enc_algo_client_to_server=" + np.enc_algo_client_to_server);
187 log.log(20, "enc_algo_server_to_client=" + np.enc_algo_server_to_client);
188 np.mac_algo_client_to_server = getFirstMatch(client.mac_algorithms_client_to_server,
189 server.mac_algorithms_client_to_server);
190 np.mac_algo_server_to_client = getFirstMatch(client.mac_algorithms_server_to_client,
191 server.mac_algorithms_server_to_client);
192 log.log(20, "mac_algo_client_to_server=" + np.mac_algo_client_to_server);
193 log.log(20, "mac_algo_server_to_client=" + np.mac_algo_server_to_client);
194 np.comp_algo_client_to_server = getFirstMatch(client.compression_algorithms_client_to_server,
195 server.compression_algorithms_client_to_server);
196 np.comp_algo_server_to_client = getFirstMatch(client.compression_algorithms_server_to_client,
197 server.compression_algorithms_server_to_client);
198 log.log(20, "comp_algo_client_to_server=" + np.comp_algo_client_to_server);
199 log.log(20, "comp_algo_server_to_client=" + np.comp_algo_server_to_client);
200 }
201 catch (NegotiateException e) {
202 return null;
203 }
204
205 try {
206 np.lang_client_to_server = getFirstMatch(client.languages_client_to_server,
207 server.languages_client_to_server);
208 }
209 catch (NegotiateException e1) {
210 np.lang_client_to_server = null;
211 }
212
213 try {
214 np.lang_server_to_client = getFirstMatch(client.languages_server_to_client,
215 server.languages_server_to_client);
216 }
217 catch (NegotiateException e2) {
218 np.lang_server_to_client = null;
219 }
220
221 if (isGuessOK(client, server))
222 np.guessOK = true;
223
224 return np;
225 }
226
227 public synchronized void initiateKEX(CryptoWishList cwl, DHGexParameters dhgex) throws IOException {
228 nextKEXcryptoWishList = cwl;
229 nextKEXdhgexParameters = dhgex;
230
231 if (kxs == null) {
232 kxs = new KexState();
233 kxs.dhgexParameters = nextKEXdhgexParameters;
234 PacketKexInit kp = new PacketKexInit(nextKEXcryptoWishList);
235 kxs.localKEX = kp;
236 tm.sendKexMessage(kp.getPayload());
237 }
238 }
239
240 private boolean establishKeyMaterial() {
241 try {
242 int mac_cs_key_len = MAC.getKeyLen(kxs.np.mac_algo_client_to_server);
243 int enc_cs_key_len = BlockCipherFactory.getKeySize(kxs.np.enc_algo_client_to_server);
244 int enc_cs_block_len = BlockCipherFactory.getBlockSize(kxs.np.enc_algo_client_to_server);
245 int mac_sc_key_len = MAC.getKeyLen(kxs.np.mac_algo_server_to_client);
246 int enc_sc_key_len = BlockCipherFactory.getKeySize(kxs.np.enc_algo_server_to_client);
247 int enc_sc_block_len = BlockCipherFactory.getBlockSize(kxs.np.enc_algo_server_to_client);
248 km = KeyMaterial.create(kxs.hashAlgo, kxs.H, kxs.K, sessionId, enc_cs_key_len, enc_cs_block_len, mac_cs_key_len,
249 enc_sc_key_len, enc_sc_block_len, mac_sc_key_len);
250 }
251 catch (IllegalArgumentException e) {
252 return false;
253 }
254
255 return true;
256 }
257
258 private void finishKex() throws IOException {
259 if (sessionId == null)
260 sessionId = kxs.H;
261
262 establishKeyMaterial();
263 /* Tell the other side that we start using the new material */
264 PacketNewKeys ign = new PacketNewKeys();
265 tm.sendKexMessage(ign.getPayload());
266 BlockCipher cbc;
267 MAC mac;
268 ICompressor comp;
269
270 try {
271 cbc = BlockCipherFactory.createCipher(kxs.np.enc_algo_client_to_server, true, km.enc_key_client_to_server,
272 km.initial_iv_client_to_server);
273 mac = new MAC(kxs.np.mac_algo_client_to_server, km.integrity_key_client_to_server);
274 comp = CompressionFactory.createCompressor(kxs.np.comp_algo_client_to_server);
275 }
276 catch (IllegalArgumentException e1) {
277 throw new IOException("Fatal error during MAC startup!");
278 }
279
280 tm.changeSendCipher(cbc, mac);
281 tm.changeSendCompression(comp);
282 tm.kexFinished();
283 }
284
285 public static final String[] getDefaultServerHostkeyAlgorithmList() {
286 return HOSTKEY_ALGS.toArray(new String[HOSTKEY_ALGS.size()]);
287 }
288
289 public static final void checkServerHostkeyAlgorithmsList(String[] algos) {
290 for (int i = 0; i < algos.length; i++) {
291 if (!HOSTKEY_ALGS.contains(algos[i]))
292 throw new IllegalArgumentException("Unknown server host key algorithm '" + algos[i] + "'");
293 }
294 }
295
296 public static final String[] getDefaultKexAlgorithmList() {
297 return KEX_ALGS.toArray(new String[KEX_ALGS.size()]);
298 }
299
300 public static final void checkKexAlgorithmList(String[] algos) {
301 for (int i = 0; i < algos.length; i++) {
302 if (!KEX_ALGS.contains(algos[i]))
303 throw new IllegalArgumentException("Unknown kex algorithm '" + algos[i] + "'");
304 }
305 }
306
307 private boolean verifySignature(byte[] sig, byte[] hostkey) throws IOException {
308 if (kxs.np.server_host_key_algo.startsWith("ecdsa-sha2-")) {
309 byte[] rs = ECDSASHA2Verify.decodeSSHECDSASignature(sig);
310 ECPublicKey epk = ECDSASHA2Verify.decodeSSHECDSAPublicKey(hostkey);
311 log.log(50, "Verifying ecdsa signature");
312 return ECDSASHA2Verify.verifySignature(kxs.H, rs, epk);
313 }
314
315 if (kxs.np.server_host_key_algo.equals("ssh-rsa")) {
316 byte[] rs = RSASHA1Verify.decodeSSHRSASignature(sig);
317 RSAPublicKey rpk = RSASHA1Verify.decodeSSHRSAPublicKey(hostkey);
318 log.log(50, "Verifying ssh-rsa signature");
319 return RSASHA1Verify.verifySignature(kxs.H, rs, rpk);
320 }
321
322 if (kxs.np.server_host_key_algo.equals("ssh-dss")) {
323 byte[] ds = DSASHA1Verify.decodeSSHDSASignature(sig);
324 DSAPublicKey dpk = DSASHA1Verify.decodeSSHDSAPublicKey(hostkey);
325 log.log(50, "Verifying ssh-dss signature");
326 return DSASHA1Verify.verifySignature(kxs.H, ds, dpk);
327 }
328
329 throw new IOException("Unknown server host key algorithm '" + kxs.np.server_host_key_algo + "'");
330 }
331
332 public synchronized void handleMessage(byte[] msg, int msglen) throws IOException {
333 PacketKexInit kip;
334
335 if (msg == null) {
336 synchronized (accessLock) {
337 connectionClosed = true;
338 accessLock.notifyAll();
339 return;
340 }
341 }
342
343 if ((kxs == null) && (msg[0] != Packets.SSH_MSG_KEXINIT))
344 throw new IOException("Unexpected KEX message (type " + msg[0] + ")");
345
346 if (ignore_next_kex_packet) {
347 ignore_next_kex_packet = false;
348 return;
349 }
350
351 if (msg[0] == Packets.SSH_MSG_KEXINIT) {
352 if ((kxs != null) && (kxs.state != 0))
353 throw new IOException("Unexpected SSH_MSG_KEXINIT message during on-going kex exchange!");
354
355 if (kxs == null) {
356 /*
357 * Ah, OK, peer wants to do KEX. Let's be nice and play
358 * together.
359 */
360 kxs = new KexState();
361 kxs.dhgexParameters = nextKEXdhgexParameters;
362 kip = new PacketKexInit(nextKEXcryptoWishList);
363 kxs.localKEX = kip;
364 tm.sendKexMessage(kip.getPayload());
365 }
366
367 kip = new PacketKexInit(msg, 0, msglen);
368 kxs.remoteKEX = kip;
369 kxs.np = mergeKexParameters(kxs.localKEX.getKexParameters(), kxs.remoteKEX.getKexParameters());
370
371 if (kxs.np == null)
372 throw new IOException("Cannot negotiate, proposals do not match.");
373
374 if (kxs.remoteKEX.isFirst_kex_packet_follows() && (kxs.np.guessOK == false)) {
375 /*
376 * Guess was wrong, we need to ignore the next kex packet.
377 */
378 ignore_next_kex_packet = true;
379 }
380
381 if (kxs.np.kex_algo.equals("diffie-hellman-group-exchange-sha1")
382 || kxs.np.kex_algo.equals("diffie-hellman-group-exchange-sha256")) {
383 if (kxs.dhgexParameters.getMin_group_len() == 0 || csh.server_versioncomment.matches("OpenSSH_2\\.([0-4]\\.|5\\.[0-2]).*")) {
384 PacketKexDhGexRequestOld dhgexreq = new PacketKexDhGexRequestOld(kxs.dhgexParameters);
385 tm.sendKexMessage(dhgexreq.getPayload());
386 }
387 else {
388 PacketKexDhGexRequest dhgexreq = new PacketKexDhGexRequest(kxs.dhgexParameters);
389 tm.sendKexMessage(dhgexreq.getPayload());
390 }
391
392 if (kxs.np.kex_algo.endsWith("sha1")) {
393 kxs.hashAlgo = "SHA1";
394 }
395 else {
396 kxs.hashAlgo = "SHA-256";
397 }
398
399 kxs.state = 1;
400 return;
401 }
402
403 if (kxs.np.kex_algo.equals("diffie-hellman-group1-sha1")
404 || kxs.np.kex_algo.equals("diffie-hellman-group14-sha1")
405 || kxs.np.kex_algo.equals("ecdh-sha2-nistp256")
406 || kxs.np.kex_algo.equals("ecdh-sha2-nistp384")
407 || kxs.np.kex_algo.equals("ecdh-sha2-nistp521")) {
408 kxs.dhx = GenericDhExchange.getInstance(kxs.np.kex_algo);
409 kxs.dhx.init(kxs.np.kex_algo);
410 kxs.hashAlgo = kxs.dhx.getHashAlgo();
411 PacketKexDHInit kp = new PacketKexDHInit(kxs.dhx.getE());
412 tm.sendKexMessage(kp.getPayload());
413 kxs.state = 1;
414 return;
415 }
416
417 throw new IllegalStateException("Unknown KEX method!");
418 }
419
420 if (msg[0] == Packets.SSH_MSG_NEWKEYS) {
421 if (km == null)
422 throw new IOException("Peer sent SSH_MSG_NEWKEYS, but I have no key material ready!");
423
424 BlockCipher cbc;
425 MAC mac;
426 ICompressor comp;
427
428 try {
429 cbc = BlockCipherFactory.createCipher(kxs.np.enc_algo_server_to_client, false,
430 km.enc_key_server_to_client, km.initial_iv_server_to_client);
431 mac = new MAC(kxs.np.mac_algo_server_to_client, km.integrity_key_server_to_client);
432 comp = CompressionFactory.createCompressor(kxs.np.comp_algo_server_to_client);
433 }
434 catch (IllegalArgumentException e1) {
435 throw new IOException("Fatal error during MAC startup!");
436 }
437
438 tm.changeRecvCipher(cbc, mac);
439 tm.changeRecvCompression(comp);
440 ConnectionInfo sci = new ConnectionInfo();
441 kexCount++;
442 sci.keyExchangeAlgorithm = kxs.np.kex_algo;
443 sci.keyExchangeCounter = kexCount;
444 sci.clientToServerCryptoAlgorithm = kxs.np.enc_algo_client_to_server;
445 sci.serverToClientCryptoAlgorithm = kxs.np.enc_algo_server_to_client;
446 sci.clientToServerMACAlgorithm = kxs.np.mac_algo_client_to_server;
447 sci.serverToClientMACAlgorithm = kxs.np.mac_algo_server_to_client;
448 sci.serverHostKeyAlgorithm = kxs.np.server_host_key_algo;
449 sci.serverHostKey = kxs.hostkey;
450
451 synchronized (accessLock) {
452 lastConnInfo = sci;
453 accessLock.notifyAll();
454 }
455
456 kxs = null;
457 return;
458 }
459
460 if ((kxs == null) || (kxs.state == 0))
461 throw new IOException("Unexpected Kex submessage!");
462
463 if (kxs.np.kex_algo.equals("diffie-hellman-group-exchange-sha1")
464 || kxs.np.kex_algo.equals("diffie-hellman-group-exchange-sha256")) {
465 if (kxs.state == 1) {
466 PacketKexDhGexGroup dhgexgrp = new PacketKexDhGexGroup(msg, 0, msglen);
467 kxs.dhgx = new DhGroupExchange(dhgexgrp.getP(), dhgexgrp.getG());
468 kxs.dhgx.init(rnd);
469 PacketKexDhGexInit dhgexinit = new PacketKexDhGexInit(kxs.dhgx.getE());
470 tm.sendKexMessage(dhgexinit.getPayload());
471 kxs.state = 2;
472 return;
473 }
474
475 if (kxs.state == 2) {
476 PacketKexDhGexReply dhgexrpl = new PacketKexDhGexReply(msg, 0, msglen);
477 kxs.hostkey = dhgexrpl.getHostKey();
478
479 if (verifier != null) {
480 boolean vres = false;
481
482 try {
483 vres = verifier.verifyServerHostKey(hostname, port, kxs.np.server_host_key_algo, kxs.hostkey);
484 }
485 catch (Exception e) {
486 throw(IOException) new IOException(
487 "The server hostkey was not accepted by the verifier callback.").initCause(e);
488 }
489
490 if (vres == false)
491 throw new IOException("The server hostkey was not accepted by the verifier callback");
492 }
493
494 kxs.dhgx.setF(dhgexrpl.getF());
495
496 try {
497 kxs.H = kxs.dhgx.calculateH(kxs.hashAlgo,
498 csh.getClientString(), csh.getServerString(),
499 kxs.localKEX.getPayload(), kxs.remoteKEX.getPayload(),
500 dhgexrpl.getHostKey(), kxs.dhgexParameters);
501 }
502 catch (IllegalArgumentException e) {
503 throw(IOException) new IOException("KEX error.").initCause(e);
504 }
505
506 boolean res = verifySignature(dhgexrpl.getSignature(), kxs.hostkey);
507
508 if (res == false)
509 throw new IOException("Hostkey signature sent by remote is wrong!");
510
511 kxs.K = kxs.dhgx.getK();
512 finishKex();
513 kxs.state = -1;
514 return;
515 }
516
517 throw new IllegalStateException("Illegal State in KEX Exchange!");
518 }
519
520 if (kxs.np.kex_algo.equals("diffie-hellman-group1-sha1")
521 || kxs.np.kex_algo.equals("diffie-hellman-group14-sha1")
522 || kxs.np.kex_algo.equals("ecdh-sha2-nistp256")
523 || kxs.np.kex_algo.equals("ecdh-sha2-nistp384")
524 || kxs.np.kex_algo.equals("ecdh-sha2-nistp521")) {
525 if (kxs.state == 1) {
526 PacketKexDHReply dhr = new PacketKexDHReply(msg, 0, msglen);
527 kxs.hostkey = dhr.getHostKey();
528
529 if (verifier != null) {
530 boolean vres = false;
531
532 try {
533 vres = verifier.verifyServerHostKey(hostname, port, kxs.np.server_host_key_algo, kxs.hostkey);
534 }
535 catch (Exception e) {
536 throw(IOException) new IOException(
537 "The server hostkey was not accepted by the verifier callback.").initCause(e);
538 }
539
540 if (vres == false)
541 throw new IOException("The server hostkey was not accepted by the verifier callback");
542 }
543
544 kxs.dhx.setF(dhr.getF());
545
546 try {
547 kxs.H = kxs.dhx.calculateH(csh.getClientString(), csh.getServerString(), kxs.localKEX.getPayload(),
548 kxs.remoteKEX.getPayload(), dhr.getHostKey());
549 }
550 catch (IllegalArgumentException e) {
551 throw(IOException) new IOException("KEX error.").initCause(e);
552 }
553
554 boolean res = verifySignature(dhr.getSignature(), kxs.hostkey);
555
556 if (res == false)
557 throw new IOException("Hostkey signature sent by remote is wrong!");
558
559 kxs.K = kxs.dhx.getK();
560 finishKex();
561 kxs.state = -1;
562 return;
563 }
564 }
565
566 throw new IllegalStateException("Unkown KEX method! (" + kxs.np.kex_algo + ")");
567 }
568 }