Add share attributes + prevent download permission

apps/dav/composer/composer/autoload_classmap.php

@@ -191,6 +191,7 @@
     'OCA\\DAV\\DAV\\Sharing\\Xml\\Invite' => $baseDir . '/../lib/DAV/Sharing/Xml/Invite.php',
     'OCA\\DAV\\DAV\\Sharing\\Xml\\ShareRequest' => $baseDir . '/../lib/DAV/Sharing/Xml/ShareRequest.php',
     'OCA\\DAV\\DAV\\SystemPrincipalBackend' => $baseDir . '/../lib/DAV/SystemPrincipalBackend.php',
+    'OCA\\DAV\\DAV\\ViewOnlyPlugin' => $baseDir . '/../lib/DAV/ViewOnlyPlugin.php',
     'OCA\\DAV\\Db\\Direct' => $baseDir . '/../lib/Db/Direct.php',
     'OCA\\DAV\\Db\\DirectMapper' => $baseDir . '/../lib/Db/DirectMapper.php',
     'OCA\\DAV\\Direct\\DirectFile' => $baseDir . '/../lib/Direct/DirectFile.php',

apps/dav/composer/composer/autoload_static.php

@@ -206,6 +206,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\DAV\\Sharing\\Xml\\Invite' => __DIR__ . '/..' . '/../lib/DAV/Sharing/Xml/Invite.php',
         'OCA\\DAV\\DAV\\Sharing\\Xml\\ShareRequest' => __DIR__ . '/..' . '/../lib/DAV/Sharing/Xml/ShareRequest.php',
         'OCA\\DAV\\DAV\\SystemPrincipalBackend' => __DIR__ . '/..' . '/../lib/DAV/SystemPrincipalBackend.php',
+        'OCA\\DAV\\DAV\\ViewOnlyPlugin' => __DIR__ . '/..' . '/../lib/DAV/ViewOnlyPlugin.php',
         'OCA\\DAV\\Db\\Direct' => __DIR__ . '/..' . '/../lib/Db/Direct.php',
         'OCA\\DAV\\Db\\DirectMapper' => __DIR__ . '/..' . '/../lib/Db/DirectMapper.php',
         'OCA\\DAV\\Direct\\DirectFile' => __DIR__ . '/..' . '/../lib/Direct/DirectFile.php',

apps/dav/lib/Connector/Sabre/FilesPlugin.php

@@ -65,6 +65,7 @@ class FilesPlugin extends ServerPlugin {
 	public const PERMISSIONS_PROPERTYNAME = '{http://owncloud.org/ns}permissions';
 	public const SHARE_PERMISSIONS_PROPERTYNAME = '{http://open-collaboration-services.org/ns}share-permissions';
 	public const OCM_SHARE_PERMISSIONS_PROPERTYNAME = '{http://open-cloud-mesh.org/ns}share-permissions';
+	public const SHARE_ATTRIBUTES_PROPERTYNAME = '{http://nextcloud.org/ns}share-attributes';
 	public const DOWNLOADURL_PROPERTYNAME = '{http://owncloud.org/ns}downloadURL';
 	public const SIZE_PROPERTYNAME = '{http://owncloud.org/ns}size';
 	public const GETETAG_PROPERTYNAME = '{DAV:}getetag';
@@ -134,6 +135,7 @@ public function initialize(Server $server) {
 		$server->protectedProperties[] = self::PERMISSIONS_PROPERTYNAME;
 		$server->protectedProperties[] = self::SHARE_PERMISSIONS_PROPERTYNAME;
 		$server->protectedProperties[] = self::OCM_SHARE_PERMISSIONS_PROPERTYNAME;
+		$server->protectedProperties[] = self::SHARE_ATTRIBUTES_PROPERTYNAME;
 		$server->protectedProperties[] = self::SIZE_PROPERTYNAME;
 		$server->protectedProperties[] = self::DOWNLOADURL_PROPERTYNAME;
 		$server->protectedProperties[] = self::OWNER_ID_PROPERTYNAME;
@@ -321,6 +323,10 @@ public function handleGetProperties(PropFind $propFind, \Sabre\DAV\INode $node)
 				return json_encode($ocmPermissions);
 			});
 
+			$propFind->handle(self::SHARE_ATTRIBUTES_PROPERTYNAME, function () use ($node, $httpRequest) {
+				return json_encode($node->getShareAttributes());
+			});
+
 			$propFind->handle(self::GETETAG_PROPERTYNAME, function () use ($node): string {
 				return $node->getETag();
 			});

apps/dav/lib/Connector/Sabre/Node.php

@@ -38,6 +38,7 @@
 use OC\Files\Mount\MoveableMount;
 use OC\Files\Node\File;
 use OC\Files\Node\Folder;
+use OC\Files\Storage\Wrapper\Wrapper;
 use OC\Files\View;
 use OCA\DAV\Connector\Sabre\Exception\InvalidPath;
 use OCP\Files\FileInfo;
@@ -322,6 +323,31 @@ public function getSharePermissions($user) {
 		return $permissions;
 	}
 
+	/**
+	 * @return array
+	 */
+	public function getShareAttributes(): array {
+		$attributes = [];
+
+		try {
+			$storage = $this->info->getStorage();
+		} catch (StorageNotAvailableException $e) {
+			$storage = null;
+		}
+
+		if ($storage && $storage->instanceOfStorage(\OCA\Files_Sharing\SharedStorage::class)) {
+			/** @var \OCA\Files_Sharing\SharedStorage $storage */
+			$attributes = $storage->getShare()->getAttributes();
+			if ($attributes === null) {
+				return [];
+			} else {
+				return $attributes->toArray();
+			}
+		}
+
+		return $attributes;
+	}
+
 	/**
 	 * @param string $user
 	 * @return string

apps/dav/lib/Connector/Sabre/ServerFactory.php

@@ -33,6 +33,7 @@
 
 use OCP\Files\Folder;
 use OCA\DAV\AppInfo\PluginManager;
+use OCA\DAV\DAV\ViewOnlyPlugin;
 use OCA\DAV\Files\BrowserErrorPagePlugin;
 use OCP\Files\Mount\IMountManager;
 use OCP\IConfig;
@@ -158,6 +159,11 @@ public function createServer(string $baseUri,
 			$server->addPlugin(new \OCA\DAV\Connector\Sabre\QuotaPlugin($view, true));
 			$server->addPlugin(new \OCA\DAV\Connector\Sabre\ChecksumUpdatePlugin());
 
+			// Allow view-only plugin for webdav requests
+			$server->addPlugin(new ViewOnlyPlugin(
+				$this->logger
+			));
+
 			if ($this->userSession->isLoggedIn()) {
 				$server->addPlugin(new \OCA\DAV\Connector\Sabre\TagsPlugin($objectTree, $this->tagManager));
 				$server->addPlugin(new \OCA\DAV\Connector\Sabre\SharesPlugin(

apps/dav/lib/Controller/DirectController.php

@@ -31,8 +31,12 @@
 use OCP\AppFramework\Http\DataResponse;
 use OCP\AppFramework\OCS\OCSBadRequestException;
 use OCP\AppFramework\OCS\OCSNotFoundException;
+use OCP\AppFramework\OCS\OCSForbiddenException;
 use OCP\AppFramework\OCSController;
 use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\EventDispatcher\GenericEvent;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\Files\Events\BeforeDirectFileDownloadEvent;
 use OCP\Files\File;
 use OCP\Files\IRootFolder;
 use OCP\IRequest;
@@ -59,6 +63,8 @@ class DirectController extends OCSController {
 	/** @var IURLGenerator */
 	private $urlGenerator;
 
+	/** @var IEventDispatcher */
+	private $eventDispatcher;
 
 	public function __construct(string $appName,
 								IRequest $request,
@@ -67,7 +73,8 @@ public function __construct(string $appName,
 								DirectMapper $mapper,
 								ISecureRandom $random,
 								ITimeFactory $timeFactory,
-								IURLGenerator $urlGenerator) {
+								IURLGenerator $urlGenerator,
+								IEventDispatcher $eventDispatcher) {
 		parent::__construct($appName, $request);
 
 		$this->rootFolder = $rootFolder;
@@ -76,6 +83,7 @@ public function __construct(string $appName,
 		$this->random = $random;
 		$this->timeFactory = $timeFactory;
 		$this->urlGenerator = $urlGenerator;
+		$this->eventDispatcher = $eventDispatcher;
 	}
 
 	/**
@@ -99,6 +107,13 @@ public function getUrl(int $fileId, int $expirationTime = 60 * 60 * 8): DataResp
 			throw new OCSBadRequestException('Direct download only works for files');
 		}
 
+		$event = new BeforeDirectFileDownloadEvent($userFolder->getRelativePath($file->getPath()));
+		$this->eventDispatcher->dispatchTyped($event);
+
+		if ($event->isSuccessful() === false) {
+			throw new OCSForbiddenException('Permission denied to download file');
+		}
+
 		//TODO: at some point we should use the directdownlaod function of storages
 		$direct = new Direct();
 		$direct->setUserId($this->userId);

apps/dav/lib/DAV/ViewOnlyPlugin.php

@@ -0,0 +1,108 @@
+<?php
+/**
+ * @author Piotr Mrowczynski piotr@owncloud.com
+ *
+ * @copyright Copyright (c) 2019, ownCloud GmbH
+ * @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\DAV\DAV;
+
+use OCA\DAV\Connector\Sabre\Exception\Forbidden;
+use OCA\DAV\Connector\Sabre\File as DavFile;
+use OCA\DAV\Meta\MetaFile;
+use OCP\Files\FileInfo;
+use OCP\Files\NotFoundException;
+use Psr\Log\LoggerInterface;
+use Sabre\DAV\Server;
+use Sabre\DAV\ServerPlugin;
+use Sabre\HTTP\RequestInterface;
+use Sabre\DAV\Exception\NotFound;
+
+/**
+ * Sabre plugin for restricting file share receiver download:
+ */
+class ViewOnlyPlugin extends ServerPlugin {
+
+	private ?Server $server = null;
+	private LoggerInterface $logger;
+
+	public function __construct(LoggerInterface $logger) {
+		$this->logger = $logger;
+	}
+
+	/**
+	 * This initializes the plugin.
+	 *
+	 * This function is called by Sabre\DAV\Server, after
+	 * addPlugin is called.
+	 *
+	 * This method should set up the required event subscriptions.
+	 */
+	public function initialize(Server $server): void {
+		$this->server = $server;
+		//priority 90 to make sure the plugin is called before
+		//Sabre\DAV\CorePlugin::httpGet
+		$this->server->on('method:GET', [$this, 'checkViewOnly'], 90);
+	}
+
+	/**
+	 * Disallow download via DAV Api in case file being received share
+	 * and having special permission
+	 *
+	 * @throws Forbidden
+	 * @throws NotFoundException
+	 */
+	public function checkViewOnly(RequestInterface $request): bool {
+		$path = $request->getPath();
+
+		try {
+			assert($this->server !== null);
+			$davNode = $this->server->tree->getNodeForPath($path);
+			if (!($davNode instanceof DavFile)) {
+				return true;
+			}
+			// Restrict view-only to nodes which are shared
+			$node = $davNode->getNode();
+
+			$storage = $node->getStorage();
+
+			if (!$storage->instanceOfStorage(\OCA\Files_Sharing\SharedStorage::class)) {
+				return true;
+			}
+			// Extract extra permissions
+			/** @var \OCA\Files_Sharing\SharedStorage $storage */
+			$share = $storage->getShare();
+
+			$attributes = $share->getAttributes();
+			if ($attributes === null) {
+				return true;
+			}
+
+			// Check if read-only and on whether permission can download is both set and disabled.
+			$canDownload = $attributes->getAttribute('permissions', 'download');
+			if ($canDownload !== null && !$canDownload) {
+				throw new Forbidden('Access to this resource has been denied because it is in view-only mode.');
+			}
+		} catch (NotFound $e) {
+			$this->logger->warning($e->getMessage(), [
+				'exception' => $e,
+			]);
+		}
+
+		return true;
+	}
+}

apps/dav/lib/Server.php

@@ -62,6 +62,7 @@
 use OCA\DAV\Connector\Sabre\TagsPlugin;
 use OCA\DAV\DAV\CustomPropertiesBackend;
 use OCA\DAV\DAV\PublicAuth;
+use OCA\DAV\DAV\ViewOnlyPlugin;
 use OCA\DAV\Events\SabrePluginAuthInitEvent;
 use OCA\DAV\Files\BrowserErrorPagePlugin;
 use OCA\DAV\Files\LazySearchBackend;
@@ -229,6 +230,11 @@ public function __construct(IRequest $request, string $baseUri) {
 			$this->server->addPlugin(new FakeLockerPlugin());
 		}
 
+		// Allow view-only plugin for webdav requests
+		$this->server->addPlugin(new ViewOnlyPlugin(
+			$logger
+		));
+
 		if (BrowserErrorPagePlugin::isBrowserRequest($request)) {
 			$this->server->addPlugin(new BrowserErrorPagePlugin());
 		}

apps/dav/tests/unit/Connector/Sabre/NodeTest.php

@@ -29,8 +29,11 @@
 
 use OC\Files\FileInfo;
 use OC\Files\View;
+use OC\Share20\ShareAttributes;
+use OCA\Files_Sharing\SharedStorage;
 use OCP\Files\Mount\IMountPoint;
 use OCP\Files\Storage;
+use OCP\Share\IAttributes;
 use OCP\Share\IManager;
 use OCP\Share\IShare;
 
@@ -169,6 +172,65 @@ public function testSharePermissions($type, $user, $permissions, $expected) {
 		$this->assertEquals($expected, $node->getSharePermissions($user));
 	}
 
+	public function testShareAttributes() {
+		$storage = $this->getMockBuilder(SharedStorage::class)
+			->disableOriginalConstructor()
+			->setMethods(['getShare'])
+			->getMock();
+
+		$shareManager = $this->getMockBuilder(IManager::class)->disableOriginalConstructor()->getMock();
+		$share = $this->getMockBuilder(IShare::class)->disableOriginalConstructor()->getMock();
+
+		$storage->expects($this->once())
+			->method('getShare')
+			->willReturn($share);
+
+		$attributes = new ShareAttributes();
+		$attributes->setAttribute('permissions', 'download', false);
+
+		$share->expects($this->once())->method('getAttributes')->willReturn($attributes);
+
+		$info = $this->getMockBuilder(FileInfo::class)
+			->disableOriginalConstructor()
+			->setMethods(['getStorage', 'getType'])
+			->getMock();
+
+		$info->method('getStorage')->willReturn($storage);
+		$info->method('getType')->willReturn(FileInfo::TYPE_FOLDER);
+
+		$view = $this->getMockBuilder(View::class)
+			->disableOriginalConstructor()
+			->getMock();
+
+		$node = new \OCA\DAV\Connector\Sabre\File($view, $info);
+		$this->invokePrivate($node, 'shareManager', [$shareManager]);
+		$this->assertEquals($attributes->toArray(), $node->getShareAttributes());
+	}
+
+	public function testShareAttributesNonShare() {
+		$storage = $this->getMockBuilder(Storage::class)
+			->disableOriginalConstructor()
+			->getMock();
+
+		$shareManager = $this->getMockBuilder(IManager::class)->disableOriginalConstructor()->getMock();
+
+		$info = $this->getMockBuilder(FileInfo::class)
+			->disableOriginalConstructor()
+			->setMethods(['getStorage', 'getType'])
+			->getMock();
+
+		$info->method('getStorage')->willReturn($storage);
+		$info->method('getType')->willReturn(FileInfo::TYPE_FOLDER);
+
+		$view = $this->getMockBuilder(View::class)
+			->disableOriginalConstructor()
+			->getMock();
+
+		$node = new \OCA\DAV\Connector\Sabre\File($view, $info);
+		$this->invokePrivate($node, 'shareManager', [$shareManager]);
+		$this->assertEquals([], $node->getShareAttributes());
+	}
+
 	public function sanitizeMtimeProvider() {
 		return [
 			[123456789, 123456789],