Validate user name during registration

src/main/java/envoy/server/processors/LoginCredentialProcessor.java

@@ -20,6 +20,7 @@ import envoy.server.data.PersistenceManager;
 import envoy.server.data.User;
 import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
+import envoy.util.Bounds;
 import envoy.util.EnvoyLog;
 
 /**
@@ -76,6 +77,12 @@ public final class LoginCredentialProcessor implements ObjectProcessor<LoginCred
 				return;
 			}
 		} else {
+			// Validate user name
+			if (!Bounds.isValidContactName(credentials.getIdentifier())) {
+				logger.info("The requested user name is not valid.");
+				writeProxy.write(socketID, new HandshakeRejection(INTERNAL_ERROR));
+				return;
+			}
 				try {
 					// Checking that no user already has this identifier
 					PersistenceManager.getInstance().getUserByName(credentials.getIdentifier());