core:GenerateGroups: Fix use of "/e" preg_replace modifier.

See: https://wiki.php.net/rfc/remove_preg_replace_eval_modifier

Thanks to Thijs Kinkhorst for providing this patch!

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@3223 44740490-163a-0410-bde0-09ae8108e29a

modules/core/lib/Auth/Process/GenerateGroups.php

@@ -135,11 +135,9 @@ class sspmod_core_Auth_Process_GenerateGroups extends SimpleSAML_Auth_Processing
 	private static function escapeIllegalChars($string) {
 		assert('is_string($string)');
 
-		/* Since preg_replace escapes both ["] and ['], while either of them isn't unescaped in the string
-		 * evaluation, we need a test to catch both of them.
-		 */
-		$replacement = '("\\1" === "\\\'") ? "%27" : sprintf("%%%02x", ord("\\1"))';
-		return preg_replace('/([^a-zA-Z0-9_@=.])/e', $replacement, $string);
+		return preg_replace_callback('/([^a-zA-Z0-9_@=.])/',
+			function ($m) { return sprintf("%%%02x", ord($m[1])); },
+			$string);
 	}
 
 }