Merge pull request #279 from TFyre/master

Fixed Kerberos SSO Challenge Response

src/java/org/jivesoftware/openfire/net/SASLAuthentication.java

@@ -275,7 +275,7 @@ public class SASLAuthentication {
                                 props.put(Sasl.SERVER_AUTH, "TRUE");
                             }
                             SaslServer ss = Sasl.createSaslServer(mechanism, "xmpp",
-                                    session.getServerName(), props,
+                                    JiveGlobals.getProperty("xmpp.fqdn", session.getServerName()), props,
                                     new XMPPCallbackHandler());
 
                             if (ss == null) {
@@ -343,10 +343,12 @@ public class SASLAuthentication {
                         if (ss != null) {
                             boolean ssComplete = ss.isComplete();
                             String response = doc.getTextTrim();
+                            if (response.length() > 0) {
                                 if (!BASE64_ENCODED.matcher(response).matches()) {
                                     authenticationFailed(session, Failure.INCORRECT_ENCODING);
                                     return Status.failed;
                                 }
+                            }
                             try {
                                 if (ssComplete) {
                                     authenticationSuccessful(session, ss.getAuthorizationID(),