Mercurial > 510Connectbot
comparison src/ch/ethz/ssh2/KnownHosts.java @ 273:91a31873c42a ganymed
start conversion from trilead to ganymed
author | Carl Byington <carl@five-ten-sg.com> |
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date | Fri, 18 Jul 2014 11:21:46 -0700 |
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children | d7e088fa2123 |
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272:ce2f4e397703 | 273:91a31873c42a |
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1 /* | |
2 * Copyright (c) 2006-2011 Christian Plattner. All rights reserved. | |
3 * Please refer to the LICENSE.txt for licensing details. | |
4 */ | |
5 | |
6 package ch.ethz.ssh2; | |
7 | |
8 import java.io.BufferedReader; | |
9 import java.io.CharArrayReader; | |
10 import java.io.CharArrayWriter; | |
11 import java.io.File; | |
12 import java.io.FileReader; | |
13 import java.io.IOException; | |
14 import java.io.RandomAccessFile; | |
15 import java.net.InetAddress; | |
16 import java.net.UnknownHostException; | |
17 import java.security.DigestException; | |
18 import java.security.SecureRandom; | |
19 import java.util.ArrayList; | |
20 import java.util.LinkedList; | |
21 import java.util.List; | |
22 | |
23 import ch.ethz.ssh2.crypto.Base64; | |
24 import ch.ethz.ssh2.crypto.digest.Digest; | |
25 import ch.ethz.ssh2.crypto.digest.HMAC; | |
26 import ch.ethz.ssh2.crypto.digest.MD5; | |
27 import ch.ethz.ssh2.crypto.digest.SHA1; | |
28 import ch.ethz.ssh2.signature.DSAPublicKey; | |
29 import ch.ethz.ssh2.signature.DSASHA1Verify; | |
30 import ch.ethz.ssh2.signature.RSAPublicKey; | |
31 import ch.ethz.ssh2.signature.RSASHA1Verify; | |
32 import ch.ethz.ssh2.util.StringEncoder; | |
33 | |
34 /** | |
35 * The <code>KnownHosts</code> class is a handy tool to verify received server hostkeys | |
36 * based on the information in <code>known_hosts</code> files (the ones used by OpenSSH). | |
37 * <p/> | |
38 * It offers basically an in-memory database for known_hosts entries, as well as some | |
39 * helper functions. Entries from a <code>known_hosts</code> file can be loaded at construction time. | |
40 * It is also possible to add more keys later (e.g., one can parse different | |
41 * <code>known_hosts<code> files). | |
42 * <p/> | |
43 * It is a thread safe implementation, therefore, you need only to instantiate one | |
44 * <code>KnownHosts</code> for your whole application. | |
45 * | |
46 * @author Christian Plattner | |
47 * @version $Id: KnownHosts.java 152 2014-04-28 11:02:23Z dkocher@sudo.ch $ | |
48 */ | |
49 | |
50 public class KnownHosts { | |
51 public static final int HOSTKEY_IS_OK = 0; | |
52 public static final int HOSTKEY_IS_NEW = 1; | |
53 public static final int HOSTKEY_HAS_CHANGED = 2; | |
54 | |
55 private class KnownHostsEntry { | |
56 String[] patterns; | |
57 Object key; | |
58 | |
59 KnownHostsEntry(String[] patterns, Object key) { | |
60 this.patterns = patterns; | |
61 this.key = key; | |
62 } | |
63 } | |
64 | |
65 private final LinkedList<KnownHostsEntry> publicKeys = new LinkedList<KnownHosts.KnownHostsEntry>(); | |
66 | |
67 public KnownHosts() { | |
68 } | |
69 | |
70 public KnownHosts(char[] knownHostsData) throws IOException { | |
71 initialize(knownHostsData); | |
72 } | |
73 | |
74 public KnownHosts(String knownHosts) throws IOException { | |
75 initialize(new File(knownHosts)); | |
76 } | |
77 | |
78 public KnownHosts(File knownHosts) throws IOException { | |
79 initialize(knownHosts); | |
80 } | |
81 | |
82 /** | |
83 * Adds a single public key entry to the database. Note: this will NOT add the public key | |
84 * to any physical file (e.g., "~/.ssh/known_hosts") - use <code>addHostkeyToFile()</code> for that purpose. | |
85 * This method is designed to be used in a {@link ServerHostKeyVerifier}. | |
86 * | |
87 * @param hostnames a list of hostname patterns - at least one most be specified. Check out the | |
88 * OpenSSH sshd man page for a description of the pattern matching algorithm. | |
89 * @param serverHostKeyAlgorithm as passed to the {@link ServerHostKeyVerifier}. | |
90 * @param serverHostKey as passed to the {@link ServerHostKeyVerifier}. | |
91 * @throws IOException | |
92 */ | |
93 public void addHostkey(String hostnames[], String serverHostKeyAlgorithm, byte[] serverHostKey) throws IOException { | |
94 if(hostnames == null) { | |
95 throw new IllegalArgumentException("hostnames may not be null"); | |
96 } | |
97 | |
98 if("ssh-rsa".equals(serverHostKeyAlgorithm)) { | |
99 RSAPublicKey rpk = RSASHA1Verify.decodeSSHRSAPublicKey(serverHostKey); | |
100 | |
101 synchronized(publicKeys) { | |
102 publicKeys.add(new KnownHostsEntry(hostnames, rpk)); | |
103 } | |
104 } | |
105 else if("ssh-dss".equals(serverHostKeyAlgorithm)) { | |
106 DSAPublicKey dpk = DSASHA1Verify.decodeSSHDSAPublicKey(serverHostKey); | |
107 | |
108 synchronized(publicKeys) { | |
109 publicKeys.add(new KnownHostsEntry(hostnames, dpk)); | |
110 } | |
111 } | |
112 else { | |
113 throw new IOException(String.format("Unknown host key type %s", serverHostKeyAlgorithm)); | |
114 } | |
115 } | |
116 | |
117 /** | |
118 * Parses the given known_hosts data and adds entries to the database. | |
119 * | |
120 * @param knownHostsData | |
121 * @throws IOException | |
122 */ | |
123 public void addHostkeys(char[] knownHostsData) throws IOException { | |
124 initialize(knownHostsData); | |
125 } | |
126 | |
127 /** | |
128 * Parses the given known_hosts file and adds entries to the database. | |
129 * | |
130 * @param knownHosts | |
131 * @throws IOException | |
132 */ | |
133 public void addHostkeys(File knownHosts) throws IOException { | |
134 initialize(knownHosts); | |
135 } | |
136 | |
137 /** | |
138 * Generate the hashed representation of the given hostname. Useful for adding entries | |
139 * with hashed hostnames to a known_hosts file. (see -H option of OpenSSH key-gen). | |
140 * | |
141 * @param hostname | |
142 * @return the hashed representation, e.g., "|1|cDhrv7zwEUV3k71CEPHnhHZezhA=|Xo+2y6rUXo2OIWRAYhBOIijbJMA=" | |
143 */ | |
144 public static String createHashedHostname(String hostname) throws IOException { | |
145 SHA1 sha1 = new SHA1(); | |
146 | |
147 byte[] salt = new byte[sha1.getDigestLength()]; | |
148 | |
149 new SecureRandom().nextBytes(salt); | |
150 | |
151 byte[] hash; | |
152 try { | |
153 hash = hmacSha1Hash(salt, hostname); | |
154 } | |
155 catch(IOException e) { | |
156 throw new IOException(e); | |
157 } | |
158 | |
159 String base64_salt = new String(Base64.encode(salt)); | |
160 String base64_hash = new String(Base64.encode(hash)); | |
161 | |
162 return String.format("|1|%s|%s", base64_salt, base64_hash); | |
163 } | |
164 | |
165 private static byte[] hmacSha1Hash(byte[] salt, String hostname) throws IOException { | |
166 SHA1 sha1 = new SHA1(); | |
167 | |
168 if(salt.length != sha1.getDigestLength()) { | |
169 throw new IllegalArgumentException("Salt has wrong length (" + salt.length + ")"); | |
170 } | |
171 try { | |
172 HMAC hmac = new HMAC(sha1, salt, salt.length); | |
173 | |
174 hmac.update(StringEncoder.GetBytes(hostname)); | |
175 | |
176 byte[] dig = new byte[hmac.getDigestLength()]; | |
177 | |
178 hmac.digest(dig); | |
179 | |
180 return dig; | |
181 } | |
182 catch(DigestException e) { | |
183 throw new IOException(e); | |
184 } | |
185 } | |
186 | |
187 private boolean checkHashed(String entry, String hostname) { | |
188 if(entry.startsWith("|1|") == false) { | |
189 return false; | |
190 } | |
191 | |
192 int delim_idx = entry.indexOf('|', 3); | |
193 | |
194 if(delim_idx == -1) { | |
195 return false; | |
196 } | |
197 | |
198 String salt_base64 = entry.substring(3, delim_idx); | |
199 String hash_base64 = entry.substring(delim_idx + 1); | |
200 | |
201 byte[] salt; | |
202 byte[] hash; | |
203 | |
204 try { | |
205 salt = Base64.decode(salt_base64.toCharArray()); | |
206 hash = Base64.decode(hash_base64.toCharArray()); | |
207 } | |
208 catch(IOException e) { | |
209 return false; | |
210 } | |
211 | |
212 SHA1 sha1 = new SHA1(); | |
213 | |
214 if(salt.length != sha1.getDigestLength()) { | |
215 return false; | |
216 } | |
217 | |
218 byte[] dig = new byte[0]; | |
219 try { | |
220 dig = hmacSha1Hash(salt, hostname); | |
221 } | |
222 catch(IOException e) { | |
223 return false; | |
224 } | |
225 | |
226 for(int i = 0; i < dig.length; i++) { | |
227 if(dig[i] != hash[i]) { | |
228 return false; | |
229 } | |
230 } | |
231 | |
232 return true; | |
233 } | |
234 | |
235 private int checkKey(String remoteHostname, Object remoteKey) { | |
236 int result = HOSTKEY_IS_NEW; | |
237 | |
238 synchronized(publicKeys) { | |
239 for(KnownHostsEntry ke : publicKeys) { | |
240 if(hostnameMatches(ke.patterns, remoteHostname) == false) { | |
241 continue; | |
242 } | |
243 | |
244 boolean res = matchKeys(ke.key, remoteKey); | |
245 | |
246 if(res == true) { | |
247 return HOSTKEY_IS_OK; | |
248 } | |
249 | |
250 result = HOSTKEY_HAS_CHANGED; | |
251 } | |
252 } | |
253 return result; | |
254 } | |
255 | |
256 private List<Object> getAllKeys(String hostname) { | |
257 List<Object> keys = new ArrayList<Object>(); | |
258 | |
259 synchronized(publicKeys) { | |
260 for(KnownHostsEntry ke : publicKeys) { | |
261 if(hostnameMatches(ke.patterns, hostname) == false) { | |
262 continue; | |
263 } | |
264 | |
265 keys.add(ke.key); | |
266 } | |
267 } | |
268 | |
269 return keys; | |
270 } | |
271 | |
272 /** | |
273 * Try to find the preferred order of hostkey algorithms for the given hostname. | |
274 * Based on the type of hostkey that is present in the internal database | |
275 * (i.e., either <code>ssh-rsa</code> or <code>ssh-dss</code>) | |
276 * an ordered list of hostkey algorithms is returned which can be passed | |
277 * to <code>Connection.setServerHostKeyAlgorithms</code>. | |
278 * | |
279 * @param hostname | |
280 * @return <code>null</code> if no key for the given hostname is present or | |
281 * there are keys of multiple types present for the given hostname. Otherwise, | |
282 * an array with hostkey algorithms is returned (i.e., an array of length 2). | |
283 */ | |
284 public String[] getPreferredServerHostkeyAlgorithmOrder(String hostname) { | |
285 String[] algos = recommendHostkeyAlgorithms(hostname); | |
286 | |
287 if(algos != null) { | |
288 return algos; | |
289 } | |
290 | |
291 InetAddress[] ipAdresses; | |
292 | |
293 try { | |
294 ipAdresses = InetAddress.getAllByName(hostname); | |
295 } | |
296 catch(UnknownHostException e) { | |
297 return null; | |
298 } | |
299 | |
300 for(int i = 0; i < ipAdresses.length; i++) { | |
301 algos = recommendHostkeyAlgorithms(ipAdresses[i].getHostAddress()); | |
302 | |
303 if(algos != null) { | |
304 return algos; | |
305 } | |
306 } | |
307 | |
308 return null; | |
309 } | |
310 | |
311 private boolean hostnameMatches(String[] hostpatterns, String hostname) { | |
312 boolean isMatch = false; | |
313 boolean negate; | |
314 | |
315 hostname = hostname.toLowerCase(); | |
316 | |
317 for(int k = 0; k < hostpatterns.length; k++) { | |
318 if(hostpatterns[k] == null) { | |
319 continue; | |
320 } | |
321 | |
322 String pattern; | |
323 | |
324 /* In contrast to OpenSSH we also allow negated hash entries (as well as hashed | |
325 * entries in lines with multiple entries). | |
326 */ | |
327 | |
328 if((hostpatterns[k].length() > 0) && (hostpatterns[k].charAt(0) == '!')) { | |
329 pattern = hostpatterns[k].substring(1); | |
330 negate = true; | |
331 } | |
332 else { | |
333 pattern = hostpatterns[k]; | |
334 negate = false; | |
335 } | |
336 | |
337 /* Optimize, no need to check this entry */ | |
338 | |
339 if((isMatch) && (negate == false)) { | |
340 continue; | |
341 } | |
342 | |
343 /* Now compare */ | |
344 | |
345 if(pattern.charAt(0) == '|') { | |
346 if(checkHashed(pattern, hostname)) { | |
347 if(negate) { | |
348 return false; | |
349 } | |
350 isMatch = true; | |
351 } | |
352 } | |
353 else { | |
354 pattern = pattern.toLowerCase(); | |
355 | |
356 if((pattern.indexOf('?') != -1) || (pattern.indexOf('*') != -1)) { | |
357 if(pseudoRegex(pattern.toCharArray(), 0, hostname.toCharArray(), 0)) { | |
358 if(negate) { | |
359 return false; | |
360 } | |
361 isMatch = true; | |
362 } | |
363 } | |
364 else if(pattern.compareTo(hostname) == 0) { | |
365 if(negate) { | |
366 return false; | |
367 } | |
368 isMatch = true; | |
369 } | |
370 } | |
371 } | |
372 | |
373 return isMatch; | |
374 } | |
375 | |
376 private void initialize(char[] knownHostsData) throws IOException { | |
377 BufferedReader br = new BufferedReader(new CharArrayReader(knownHostsData)); | |
378 | |
379 while(true) { | |
380 String line = br.readLine(); | |
381 | |
382 if(line == null) { | |
383 break; | |
384 } | |
385 | |
386 line = line.trim(); | |
387 | |
388 if(line.startsWith("#")) { | |
389 continue; | |
390 } | |
391 | |
392 String[] arr = line.split(" "); | |
393 | |
394 if(arr.length >= 3) { | |
395 if((arr[1].compareTo("ssh-rsa") == 0) || (arr[1].compareTo("ssh-dss") == 0)) { | |
396 String[] hostnames = arr[0].split(","); | |
397 | |
398 byte[] msg = Base64.decode(arr[2].toCharArray()); | |
399 | |
400 try { | |
401 addHostkey(hostnames, arr[1], msg); | |
402 } | |
403 catch(IOException e) { | |
404 continue; | |
405 } | |
406 } | |
407 } | |
408 } | |
409 } | |
410 | |
411 private void initialize(File knownHosts) throws IOException { | |
412 char[] buff = new char[512]; | |
413 | |
414 CharArrayWriter cw = new CharArrayWriter(); | |
415 | |
416 knownHosts.createNewFile(); | |
417 | |
418 FileReader fr = new FileReader(knownHosts); | |
419 | |
420 while(true) { | |
421 int len = fr.read(buff); | |
422 if(len < 0) { | |
423 break; | |
424 } | |
425 cw.write(buff, 0, len); | |
426 } | |
427 | |
428 fr.close(); | |
429 | |
430 initialize(cw.toCharArray()); | |
431 } | |
432 | |
433 private boolean matchKeys(Object key1, Object key2) { | |
434 if((key1 instanceof RSAPublicKey) && (key2 instanceof RSAPublicKey)) { | |
435 RSAPublicKey savedRSAKey = (RSAPublicKey) key1; | |
436 RSAPublicKey remoteRSAKey = (RSAPublicKey) key2; | |
437 | |
438 if(savedRSAKey.getE().equals(remoteRSAKey.getE()) == false) { | |
439 return false; | |
440 } | |
441 | |
442 if(savedRSAKey.getN().equals(remoteRSAKey.getN()) == false) { | |
443 return false; | |
444 } | |
445 | |
446 return true; | |
447 } | |
448 | |
449 if((key1 instanceof DSAPublicKey) && (key2 instanceof DSAPublicKey)) { | |
450 DSAPublicKey savedDSAKey = (DSAPublicKey) key1; | |
451 DSAPublicKey remoteDSAKey = (DSAPublicKey) key2; | |
452 | |
453 if(savedDSAKey.getG().equals(remoteDSAKey.getG()) == false) { | |
454 return false; | |
455 } | |
456 | |
457 if(savedDSAKey.getP().equals(remoteDSAKey.getP()) == false) { | |
458 return false; | |
459 } | |
460 | |
461 if(savedDSAKey.getQ().equals(remoteDSAKey.getQ()) == false) { | |
462 return false; | |
463 } | |
464 | |
465 if(savedDSAKey.getY().equals(remoteDSAKey.getY()) == false) { | |
466 return false; | |
467 } | |
468 | |
469 return true; | |
470 } | |
471 | |
472 return false; | |
473 } | |
474 | |
475 private boolean pseudoRegex(char[] pattern, int i, char[] match, int j) { | |
476 /* This matching logic is equivalent to the one present in OpenSSH 4.1 */ | |
477 | |
478 while(true) { | |
479 /* Are we at the end of the pattern? */ | |
480 | |
481 if(pattern.length == i) { | |
482 return (match.length == j); | |
483 } | |
484 | |
485 if(pattern[i] == '*') { | |
486 i++; | |
487 | |
488 if(pattern.length == i) { | |
489 return true; | |
490 } | |
491 | |
492 if((pattern[i] != '*') && (pattern[i] != '?')) { | |
493 while(true) { | |
494 if((pattern[i] == match[j]) && pseudoRegex(pattern, i + 1, match, j + 1)) { | |
495 return true; | |
496 } | |
497 j++; | |
498 if(match.length == j) { | |
499 return false; | |
500 } | |
501 } | |
502 } | |
503 | |
504 while(true) { | |
505 if(pseudoRegex(pattern, i, match, j)) { | |
506 return true; | |
507 } | |
508 j++; | |
509 if(match.length == j) { | |
510 return false; | |
511 } | |
512 } | |
513 } | |
514 | |
515 if(match.length == j) { | |
516 return false; | |
517 } | |
518 | |
519 if((pattern[i] != '?') && (pattern[i] != match[j])) { | |
520 return false; | |
521 } | |
522 | |
523 i++; | |
524 j++; | |
525 } | |
526 } | |
527 | |
528 private String[] recommendHostkeyAlgorithms(String hostname) { | |
529 String preferredAlgo = null; | |
530 | |
531 List<Object> keys = getAllKeys(hostname); | |
532 | |
533 for(Object key : keys) { | |
534 String thisAlgo; | |
535 | |
536 if(key instanceof RSAPublicKey) { | |
537 thisAlgo = "ssh-rsa"; | |
538 } | |
539 else if(key instanceof DSAPublicKey) { | |
540 thisAlgo = "ssh-dss"; | |
541 } | |
542 else { | |
543 continue; | |
544 } | |
545 | |
546 if(preferredAlgo != null) { | |
547 /* If we find different key types, then return null */ | |
548 | |
549 if(preferredAlgo.compareTo(thisAlgo) != 0) { | |
550 return null; | |
551 } | |
552 } | |
553 else { | |
554 preferredAlgo = thisAlgo; | |
555 } | |
556 } | |
557 | |
558 /* If we did not find anything that we know of, return null */ | |
559 | |
560 if(preferredAlgo == null) { | |
561 return null; | |
562 } | |
563 | |
564 /* Now put the preferred algo to the start of the array. | |
565 * You may ask yourself why we do it that way - basically, we could just | |
566 * return only the preferred algorithm: since we have a saved key of that | |
567 * type (sent earlier from the remote host), then that should work out. | |
568 * However, imagine that the server is (for whatever reasons) not offering | |
569 * that type of hostkey anymore (e.g., "ssh-rsa" was disabled and | |
570 * now "ssh-dss" is being used). If we then do not let the server send us | |
571 * a fresh key of the new type, then we shoot ourself into the foot: | |
572 * the connection cannot be established and hence the user cannot decide | |
573 * if he/she wants to accept the new key. | |
574 */ | |
575 | |
576 if(preferredAlgo.equals("ssh-rsa")) { | |
577 return new String[]{"ssh-rsa", "ssh-dss"}; | |
578 } | |
579 | |
580 return new String[]{"ssh-dss", "ssh-rsa"}; | |
581 } | |
582 | |
583 /** | |
584 * Checks the internal hostkey database for the given hostkey. | |
585 * If no matching key can be found, then the hostname is resolved to an IP address | |
586 * and the search is repeated using that IP address. | |
587 * | |
588 * @param hostname the server's hostname, will be matched with all hostname patterns | |
589 * @param serverHostKeyAlgorithm type of hostkey, either <code>ssh-rsa</code> or <code>ssh-dss</code> | |
590 * @param serverHostKey the key blob | |
591 * @return <ul> | |
592 * <li><code>HOSTKEY_IS_OK</code>: the given hostkey matches an entry for the given hostname</li> | |
593 * <li><code>HOSTKEY_IS_NEW</code>: no entries found for this hostname and this type of hostkey</li> | |
594 * <li><code>HOSTKEY_HAS_CHANGED</code>: hostname is known, but with another key of the same type | |
595 * (man-in-the-middle attack?)</li> | |
596 * </ul> | |
597 * @throws IOException if the supplied key blob cannot be parsed or does not match the given hostkey type. | |
598 */ | |
599 public int verifyHostkey(String hostname, String serverHostKeyAlgorithm, byte[] serverHostKey) throws IOException { | |
600 Object remoteKey; | |
601 | |
602 if("ssh-rsa".equals(serverHostKeyAlgorithm)) { | |
603 remoteKey = RSASHA1Verify.decodeSSHRSAPublicKey(serverHostKey); | |
604 } | |
605 else if("ssh-dss".equals(serverHostKeyAlgorithm)) { | |
606 remoteKey = DSASHA1Verify.decodeSSHDSAPublicKey(serverHostKey); | |
607 } | |
608 else { | |
609 throw new IllegalArgumentException("Unknown hostkey type " + serverHostKeyAlgorithm); | |
610 } | |
611 | |
612 int result = checkKey(hostname, remoteKey); | |
613 | |
614 if(result == HOSTKEY_IS_OK) { | |
615 return result; | |
616 } | |
617 | |
618 InetAddress[] ipAdresses; | |
619 | |
620 try { | |
621 ipAdresses = InetAddress.getAllByName(hostname); | |
622 } | |
623 catch(UnknownHostException e) { | |
624 return result; | |
625 } | |
626 | |
627 for(int i = 0; i < ipAdresses.length; i++) { | |
628 int newresult = checkKey(ipAdresses[i].getHostAddress(), remoteKey); | |
629 | |
630 if(newresult == HOSTKEY_IS_OK) { | |
631 return newresult; | |
632 } | |
633 | |
634 if(newresult == HOSTKEY_HAS_CHANGED) { | |
635 result = HOSTKEY_HAS_CHANGED; | |
636 } | |
637 } | |
638 | |
639 return result; | |
640 } | |
641 | |
642 /** | |
643 * Adds a single public key entry to the a known_hosts file. | |
644 * This method is designed to be used in a {@link ServerHostKeyVerifier}. | |
645 * | |
646 * @param knownHosts the file where the publickey entry will be appended. | |
647 * @param hostnames a list of hostname patterns - at least one most be specified. Check out the | |
648 * OpenSSH sshd man page for a description of the pattern matching algorithm. | |
649 * @param serverHostKeyAlgorithm as passed to the {@link ServerHostKeyVerifier}. | |
650 * @param serverHostKey as passed to the {@link ServerHostKeyVerifier}. | |
651 * @throws IOException | |
652 */ | |
653 public static void addHostkeyToFile(File knownHosts, String[] hostnames, String serverHostKeyAlgorithm, | |
654 byte[] serverHostKey) throws IOException { | |
655 if((hostnames == null) || (hostnames.length == 0)) { | |
656 throw new IllegalArgumentException("Need at least one hostname specification"); | |
657 } | |
658 | |
659 if((serverHostKeyAlgorithm == null) || (serverHostKey == null)) { | |
660 throw new IllegalArgumentException(); | |
661 } | |
662 | |
663 CharArrayWriter writer = new CharArrayWriter(); | |
664 | |
665 for(int i = 0; i < hostnames.length; i++) { | |
666 if(i != 0) { | |
667 writer.write(','); | |
668 } | |
669 writer.write(hostnames[i]); | |
670 } | |
671 | |
672 writer.write(' '); | |
673 writer.write(serverHostKeyAlgorithm); | |
674 writer.write(' '); | |
675 writer.write(Base64.encode(serverHostKey)); | |
676 writer.write("\n"); | |
677 | |
678 char[] entry = writer.toCharArray(); | |
679 | |
680 RandomAccessFile raf = new RandomAccessFile(knownHosts, "rw"); | |
681 | |
682 long len = raf.length(); | |
683 | |
684 if(len > 0) { | |
685 raf.seek(len - 1); | |
686 int last = raf.read(); | |
687 if(last != '\n') { | |
688 raf.write('\n'); | |
689 } | |
690 } | |
691 | |
692 raf.write(StringEncoder.GetBytes(new String(entry))); | |
693 raf.close(); | |
694 } | |
695 | |
696 /** | |
697 * Generates a "raw" fingerprint of a hostkey. | |
698 * | |
699 * @param type either "md5" or "sha1" | |
700 * @param keyType either "ssh-rsa" or "ssh-dss" | |
701 * @param hostkey the hostkey | |
702 * @return the raw fingerprint | |
703 */ | |
704 static private byte[] rawFingerPrint(String type, String keyType, byte[] hostkey) throws IOException { | |
705 Digest dig; | |
706 | |
707 if("md5".equals(type)) { | |
708 dig = new MD5(); | |
709 } | |
710 else if("sha1".equals(type)) { | |
711 dig = new SHA1(); | |
712 } | |
713 else { | |
714 throw new IllegalArgumentException("Unknown hash type " + type); | |
715 } | |
716 | |
717 if("ssh-rsa".equals(keyType)) { | |
718 } | |
719 else if("ssh-dss".equals(keyType)) { | |
720 } | |
721 else { | |
722 throw new IllegalArgumentException("Unknown key type " + keyType); | |
723 } | |
724 | |
725 if(hostkey == null) { | |
726 throw new IllegalArgumentException("hostkey is null"); | |
727 } | |
728 | |
729 dig.update(hostkey); | |
730 byte[] res = new byte[dig.getDigestLength()]; | |
731 try { | |
732 dig.digest(res); | |
733 } | |
734 catch(DigestException e) { | |
735 throw new IOException(e); | |
736 } | |
737 return res; | |
738 } | |
739 | |
740 /** | |
741 * Convert a raw fingerprint to hex representation (XX:YY:ZZ...). | |
742 * | |
743 * @param fingerprint raw fingerprint | |
744 * @return the hex representation | |
745 */ | |
746 static private String rawToHexFingerprint(byte[] fingerprint) { | |
747 final char[] alpha = "0123456789abcdef".toCharArray(); | |
748 | |
749 StringBuilder sb = new StringBuilder(); | |
750 | |
751 for(int i = 0; i < fingerprint.length; i++) { | |
752 if(i != 0) { | |
753 sb.append(':'); | |
754 } | |
755 int b = fingerprint[i] & 0xff; | |
756 sb.append(alpha[b >> 4]); | |
757 sb.append(alpha[b & 15]); | |
758 } | |
759 | |
760 return sb.toString(); | |
761 } | |
762 | |
763 /** | |
764 * Convert a raw fingerprint to bubblebabble representation. | |
765 * | |
766 * @param raw raw fingerprint | |
767 * @return the bubblebabble representation | |
768 */ | |
769 static private String rawToBubblebabbleFingerprint(byte[] raw) { | |
770 final char[] v = "aeiouy".toCharArray(); | |
771 final char[] c = "bcdfghklmnprstvzx".toCharArray(); | |
772 | |
773 StringBuilder sb = new StringBuilder(); | |
774 | |
775 int seed = 1; | |
776 | |
777 int rounds = (raw.length / 2) + 1; | |
778 | |
779 sb.append('x'); | |
780 | |
781 for(int i = 0; i < rounds; i++) { | |
782 if(((i + 1) < rounds) || ((raw.length) % 2 != 0)) { | |
783 sb.append(v[(((raw[2 * i] >> 6) & 3) + seed) % 6]); | |
784 sb.append(c[(raw[2 * i] >> 2) & 15]); | |
785 sb.append(v[((raw[2 * i] & 3) + (seed / 6)) % 6]); | |
786 | |
787 if((i + 1) < rounds) { | |
788 sb.append(c[(((raw[(2 * i) + 1])) >> 4) & 15]); | |
789 sb.append('-'); | |
790 sb.append(c[(((raw[(2 * i) + 1]))) & 15]); | |
791 // As long as seed >= 0, seed will be >= 0 afterwards | |
792 seed = ((seed * 5) + (((raw[2 * i] & 0xff) * 7) + (raw[(2 * i) + 1] & 0xff))) % 36; | |
793 } | |
794 } | |
795 else { | |
796 sb.append(v[seed % 6]); // seed >= 0, therefore index positive | |
797 sb.append('x'); | |
798 sb.append(v[seed / 6]); | |
799 } | |
800 } | |
801 | |
802 sb.append('x'); | |
803 | |
804 return sb.toString(); | |
805 } | |
806 | |
807 /** | |
808 * Convert a ssh2 key-blob into a human readable hex fingerprint. | |
809 * Generated fingerprints are identical to those generated by OpenSSH. | |
810 * <p/> | |
811 * Example fingerprint: d0:cb:76:19:99:5a:03:fc:73:10:70:93:f2:44:63:47. | |
812 * | |
813 * @param keytype either "ssh-rsa" or "ssh-dss" | |
814 * @param publickey key blob | |
815 * @return Hex fingerprint | |
816 */ | |
817 public static String createHexFingerprint(String keytype, byte[] publickey) throws IOException { | |
818 byte[] raw = rawFingerPrint("md5", keytype, publickey); | |
819 return rawToHexFingerprint(raw); | |
820 } | |
821 | |
822 /** | |
823 * Convert a ssh2 key-blob into a human readable bubblebabble fingerprint. | |
824 * The used bubblebabble algorithm (taken from OpenSSH) generates fingerprints | |
825 * that are easier to remember for humans. | |
826 * <p/> | |
827 * Example fingerprint: xofoc-bubuz-cazin-zufyl-pivuk-biduk-tacib-pybur-gonar-hotat-lyxux. | |
828 * | |
829 * @param keytype either "ssh-rsa" or "ssh-dss" | |
830 * @param publickey key data | |
831 * @return Bubblebabble fingerprint | |
832 */ | |
833 public static String createBubblebabbleFingerprint(String keytype, byte[] publickey) throws IOException { | |
834 byte[] raw = rawFingerPrint("sha1", keytype, publickey); | |
835 return rawToBubblebabbleFingerprint(raw); | |
836 } | |
837 } |