fixed regex for user/group lists

lam/lib/account.inc

@@ -436,7 +436,7 @@ function get_preg($argument, $regexp) {
 					break;
 		case 'usernameList':	// comma separated list of user names
 		case 'groupnameList':	// comma separated list of group names
-					$pregexpr = '[[:alpha:]]([[:alnum:]\\.\\ \\_-])(,[[:alpha:]]([[:alnum:]\\.\\ \\_-]))*';
+					$pregexpr = '/^[[:alpha:]]([[:alnum:]\\.\\ \\_-])*(,[[:alpha:]]([[:alnum:]\\.\\ \\_-])*)*$/';
 					break;
 		case 'hostname':	// first character must be letter, last must be $. Only normal letters, numbers and ._- are allowed
 					$pregexpr = '/^[a-zA-Z]([a-zA-Z0-9\\.\\_-])*\\$$/';