Blackhole requests when the action is the blackhole callback.

When a user requests the blackhole callback as an action we should
blackhole that request. The blackhole callback should not be URL
accessible.

Fixes #3496

lib/Cake/Controller/Component/SecurityComponent.php

@@ -218,6 +218,10 @@ public function startup(Controller $controller) {
 			$controller->request->params['requested'] != 1
 		);
 
+		if ($this->_action == $this->blackHoleCallback) {
+			return $this->blackhole($controller, 'auth');
+		}
+
 		if ($isPost && $isNotRequestAction && $this->validatePost) {
 			if ($this->_validatePost($controller) === false) {
 				return $this->blackHole($controller, 'auth');
@@ -309,11 +313,10 @@ public function requireAuth() {
  * @throws BadRequestException
  */
 	public function blackHole(Controller $controller, $error = '') {
-		if ($this->blackHoleCallback == null) {
+		if (!$this->blackHoleCallback) {
 			throw new BadRequestException(__d('cake_dev', 'The request has been black-holed'));
-		} else {
-			return $this->_callback($controller, $this->blackHoleCallback, array($error));
 		}
+		return $this->_callback($controller, $this->blackHoleCallback, array($error));
 	}
 
 /**

lib/Cake/Test/Case/Controller/Component/SecurityComponentTest.php

@@ -194,6 +194,22 @@ public function testBlackholeWithBrokenCallback() {
 		$this->Controller->Security->blackHole($this->Controller, 'csrf');
 	}
 
+/**
+ * Ensure that directly requesting the blackholeCallback as the controller
+ * action results in an exception.
+ *
+ * @return void
+ */
+	public function testExceptionWhenActionIsBlackholeCallback() {
+		$this->Controller->request->addParams(array(
+			'controller' => 'posts',
+			'action' => 'fail'
+		));
+		$this->assertFalse($this->Controller->failed);
+		$this->Controller->Security->startup($this->Controller);
+		$this->assertTrue($this->Controller->failed, 'Request was blackholed.');
+	}
+
 /**
  * test that initialize can set properties.
  *