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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 import ch.ethz.ssh2.KnownHosts;
      6 import ch.ethz.ssh2.ServerHostKeyVerifier;
      7 
      8 class SimpleVerifier implements ServerHostKeyVerifier
      9 {
     10 	KnownHosts database;
     11 
     12 	/*
     13 	 * This class is being used by the UsingKnownHosts.java example.
     14 	 */
     15 
     16 	public SimpleVerifier(KnownHosts database)
     17 	{
     18 		if (database == null)
     19 			throw new IllegalArgumentException();
     20 
     21 		this.database = database;
     22 	}
     23 
     24 	public boolean verifyServerHostKey(String hostname, int port, String serverHostKeyAlgorithm, byte[] serverHostKey)
     25 			throws Exception
     26 	{
     27 		int result = database.verifyHostkey(hostname, serverHostKeyAlgorithm, serverHostKey);
     28 
     29 		switch (result)
     30 		{
     31 		case KnownHosts.HOSTKEY_IS_OK:
     32 
     33 			return true; // We are happy
     34 
     35 		case KnownHosts.HOSTKEY_IS_NEW:
     36 
     37 			// Unknown host? Blindly accept the key and put it into the cache.
     38 			// Well, you definitely can do better (e.g., ask the user).
     39 
     40 			// The following call will ONLY put the key into the memory cache!
     41 			// To save it in a known hosts file, also call "KnownHosts.addHostkeyToFile(...)"
     42 			database.addHostkey(new String[] { hostname }, serverHostKeyAlgorithm, serverHostKey);
     43 
     44 			return true;
     45 
     46 		case KnownHosts.HOSTKEY_HAS_CHANGED:
     47 
     48 			// Close the connection if the hostkey has changed.
     49 			// Better: ask user and add new key to database.
     50 			return false;
     51 
     52 		default:
     53 			throw new IllegalStateException();
     54 		}
     55 	}
     56 }