Allow 2FA providers to specify their custom CSP

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

core/Controller/TwoFactorChallengeController.php

@@ -1,4 +1,5 @@
 <?php
+
 /**
  * @copyright Copyright (c) 2016, ownCloud, Inc.
  *
@@ -29,6 +30,7 @@ use OC_Util;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Http\RedirectResponse;
 use OCP\AppFramework\Http\TemplateResponse;
+use OCP\Authentication\TwoFactorAuth\IProvidesCustomCSP;
 use OCP\Authentication\TwoFactorAuth\TwoFactorException;
 use OCP\IRequest;
 use OCP\ISession;
@@ -135,7 +137,11 @@ class TwoFactorChallengeController extends Controller {
 			'redirect_url' => $redirect_url,
 			'template' => $tmpl->fetchPage(),
 		];
-		return new TemplateResponse($this->appName, 'twofactorshowchallenge', $data, 'guest');
+		$response = new TemplateResponse($this->appName, 'twofactorshowchallenge', $data, 'guest');
+		if ($provider instanceof IProvidesCustomCSP) {
+			$response->setContentSecurityPolicy($provider->getCSP());
+		}
+		return $response;
 	}
 
 	/**

lib/public/Authentication/TwoFactorAuth/IProvidesCustomCSP.php

@@ -0,0 +1,38 @@
+<?php
+
+/**
+ * @author Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCP\Authentication\TwoFactorAuth;
+
+use OCP\AppFramework\Http\ContentSecurityPolicy;
+
+/**
+ * @since 13.0.0
+ */
+interface IProvidesCustomCSP {
+
+	/**
+	 * @return ContentSecurityPolicy
+	 *
+	 * @since 13.0.0
+	 */
+	public function getCSP();
+}