1 files changed, 13 insertions, 2 deletions
diff --git a/engine/classes/ElggPAM.php b/engine/classes/ElggPAM.php
index 37436fba3..f07095fc1 100644
--- a/engine/classes/ElggPAM.php
+++ b/engine/classes/ElggPAM.php
@@ -41,18 +41,29 @@ class ElggPAM {
 	 * @param array $credentials Credentials array dependant on policy type
 	 * @return bool
 	 */
-	public function authenticate($credentials) {
+	public function authenticate($credentials = array()) {
 		global $_PAM_HANDLERS;
 
+		if (!isset($_PAM_HANDLERS[$this->policy]) ||
+			!is_array($_PAM_HANDLERS[$this->policy])) {
+			return false;
+		}
+
 		$authenticated = false;
 
 		foreach ($_PAM_HANDLERS[$this->policy] as $k => $v) {
 			$handler = $v->handler;
+			if (!is_callable($handler)) {
+				continue;
+			}
+			/* @var callable $handler */
+
 			$importance = $v->importance;
 
 			try {
 				// Execute the handler
-				$result = $handler($credentials);
+				// @todo don't assume $handler is a global function
+				$result = call_user_func($handler, $credentials);
 				if ($result) {
 					$authenticated = true;
 				} elseif ($result === false) {