Sanitize page arguments.

www/shownodetype.php3

 <?php
 #
 # EMULAB-COPYRIGHT
-# Copyright (c) 2000-2003 University of Utah and the Flux Group.
+# Copyright (c) 2000-2004 University of Utah and the Flux Group.
 # All rights reserved.
 #
 include("defs.php3");
@@ -22,6 +22,10 @@ if (!isset($node_type) ||
     strcmp($node_type, "") == 0) {
     USERERROR("You must provide a node type.", 1);
 }
+# Sanitize.
+if (!preg_match("/^[-\w]+$/", $node_type)) {
+    PAGEARGERROR("Invalid characters in arguments.");
+}
 
 #
 # Check to make sure that this is a valid nodeid