Implement password authentication mechanisms

Introduces the basic password authentication mechanism, along with a
mechanism based on ownCloud credentials stored in the user session.

Change to lib/private is an extension of PermissionsMask, as
isSharable() override was missing.

Session credentials auth mechanism now disables sharing on applied
storages, as credentials will not be available.

apps/files_external/appinfo/application.php

@@ -75,6 +75,10 @@ class Application extends App {
 
 			// AuthMechanism::SCHEME_BUILTIN mechanism
 			$container->query('OCA\Files_External\Lib\Auth\Builtin'),
+
+			// AuthMechanism::SCHEME_PASSWORD mechanisms
+			$container->query('OCA\Files_External\Lib\Auth\Password\Password'),
+			$container->query('OCA\Files_External\Lib\Auth\Password\SessionCredentials'),
 		]);
 	}
 

apps/files_external/lib/auth/password/password.php

@@ -0,0 +1,45 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCA\Files_External\Lib\Auth\Password;
+
+use \OCP\IL10N;
+use \OCA\Files_External\Lib\DefinitionParameter;
+use \OCA\Files_External\Lib\Auth\AuthMechanism;
+
+/**
+ * Basic password authentication mechanism
+ */
+class Password extends AuthMechanism {
+
+	public function __construct(IL10N $l) {
+		$this
+			->setIdentifier('password::password')
+			->setScheme(self::SCHEME_PASSWORD)
+			->setText($l->t('Username and password'))
+			->addParameters([
+				(new DefinitionParameter('user', $l->t('Username'))),
+				(new DefinitionParameter('password', $l->t('Password')))
+					->setType(DefinitionParameter::VALUE_PASSWORD),
+			]);
+	}
+
+}

apps/files_external/lib/auth/password/sessioncredentials.php

@@ -0,0 +1,84 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCA\Files_External\Lib\Auth\Password;
+
+use \OCP\IL10N;
+use \OCA\Files_External\Lib\DefinitionParameter;
+use \OCA\Files_External\Lib\Auth\AuthMechanism;
+use \OCA\Files_External\Lib\StorageConfig;
+use \OCP\ISession;
+use \OCP\Security\ICrypto;
+use \OCP\Files\Storage;
+use \OCA\Files_External\Lib\SessionStorageWrapper;
+use \OCA\Files_External\Lib\InsufficientDataForMeaningfulAnswerException;
+
+/**
+ * Username and password from login credentials, saved in session
+ */
+class SessionCredentials extends AuthMechanism {
+
+	/** @var ISession */
+	protected $session;
+
+	/** @var ICrypto */
+	protected $crypto;
+
+	public function __construct(IL10N $l, ISession $session, ICrypto $crypto) {
+		$this->session = $session;
+		$this->crypto = $crypto;
+
+		$this
+			->setIdentifier('password::sessioncredentials')
+			->setScheme(self::SCHEME_PASSWORD)
+			->setText($l->t('Session credentials'))
+			->addParameters([
+			])
+		;
+
+		\OCP\Util::connectHook('OC_User', 'post_login', $this, 'authenticate');
+	}
+
+	/**
+	 * Hook listener on post login
+	 *
+	 * @param array $params
+	 */
+	public function authenticate(array $params) {
+		$this->session->set('password::sessioncredentials/credentials', $this->crypto->encrypt(json_encode($params)));
+	}
+
+	public function manipulateStorageConfig(StorageConfig &$storage) {
+		$encrypted = $this->session->get('password::sessioncredentials/credentials');
+		if (!isset($encrypted)) {
+			throw new InsufficientDataForMeaningfulAnswerException('No session credentials saved');
+		}
+
+		$credentials = json_decode($this->crypto->decrypt($encrypted), true);
+		$storage->setBackendOption('user', $this->session->get('loginname'));
+		$storage->setBackendOption('password', $credentials['password']);
+	}
+
+	public function wrapStorage(Storage $storage) {
+		return new SessionStorageWrapper(['storage' => $storage]);
+	}
+
+}

apps/files_external/lib/sessionstoragewrapper.php

@@ -0,0 +1,43 @@
+<?php
+/**
+ * @author Robin McCorkell <rmccorkell@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCA\Files_External\Lib;
+
+use \OCP\Files\Storage;
+use \OC\Files\Storage\Wrapper\PermissionsMask;
+use \OCP\Constants;
+
+/**
+ * Wrap Storage in PermissionsMask for session ephemeral use
+ */
+class SessionStorageWrapper extends PermissionsMask {
+
+	/**
+	 * @param array $arguments ['storage' => $storage]
+	 */
+	public function __construct(array $arguments) {
+		// disable sharing permission
+		$arguments['mask'] = Constants::PERMISSION_ALL & ~Constants::PERMISSION_SHARE;
+		parent::__construct($arguments);
+	}
+
+}
+

lib/private/files/storage/wrapper/permissionsmask.php

@@ -65,6 +65,10 @@ class PermissionsMask extends Wrapper {
 		return $this->checkMask(Constants::PERMISSION_DELETE) and parent::isDeletable($path);
 	}
 
+	public function isSharable($path) {
+		return $this->checkMask(Constants::PERMISSION_SHARE) and parent::isSharable($parm);
+	}
+
 	public function getPermissions($path) {
 		return $this->storage->getPermissions($path) & $this->mask;
 	}