Improved path regex in system.inc.php

Author: Till Brehm

server/lib/classes/system.inc.php

@@ -851,7 +851,7 @@ function checkpath($path) {
 
 		//* We allow only some characters in the path
 		// * is allowed, for example it is part of wildcard certificates/keys: *.example.com.crt
-		if(!preg_match('@^/[-a-zA-Z0-9_/.*~]{1,}$@', $path)) return false;
+		if(!preg_match('@^/[-a-zA-Z0-9_/.*]{1,}[~]?$@', $path)) return false;
 
 		//* Check path for symlinks
 		$path_parts = explode('/', $path);