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107 lines
3.1 KiB
PHP
107 lines
3.1 KiB
PHP
<?php
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/**
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* SPDX-FileCopyrightText: 2022-2024 Nextcloud GmbH and Nextcloud contributors
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* SPDX-FileCopyrightText: 2019 ownCloud GmbH
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* SPDX-License-Identifier: AGPL-3.0-only
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*/
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namespace OCA\DAV\DAV;
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use OCA\DAV\Connector\Sabre\Exception\Forbidden;
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use OCA\DAV\Connector\Sabre\File as DavFile;
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use OCA\Files_Versions\Sabre\VersionFile;
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use OCP\Files\Folder;
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use OCP\Files\NotFoundException;
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use OCP\Files\Storage\ISharedStorage;
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use Sabre\DAV\Exception\NotFound;
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use Sabre\DAV\Server;
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use Sabre\DAV\ServerPlugin;
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use Sabre\HTTP\RequestInterface;
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/**
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* Sabre plugin for restricting file share receiver download:
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*/
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class ViewOnlyPlugin extends ServerPlugin {
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private ?Server $server = null;
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public function __construct(
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private ?Folder $userFolder,
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) {
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}
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/**
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* This initializes the plugin.
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*
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* This function is called by Sabre\DAV\Server, after
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* addPlugin is called.
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*
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* This method should set up the required event subscriptions.
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*/
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public function initialize(Server $server): void {
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$this->server = $server;
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//priority 90 to make sure the plugin is called before
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//Sabre\DAV\CorePlugin::httpGet
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$this->server->on('method:GET', [$this, 'checkViewOnly'], 90);
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$this->server->on('method:COPY', [$this, 'checkViewOnly'], 90);
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$this->server->on('method:MOVE', [$this, 'checkViewOnly'], 90);
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}
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/**
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* Disallow download via DAV Api in case file being received share
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* and having special permission
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*
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* @throws Forbidden
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* @throws NotFoundException
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*/
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public function checkViewOnly(RequestInterface $request): bool {
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$path = $request->getPath();
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try {
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assert($this->server !== null);
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$davNode = $this->server->tree->getNodeForPath($path);
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if ($davNode instanceof DavFile) {
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// Restrict view-only to nodes which are shared
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$node = $davNode->getNode();
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} elseif ($davNode instanceof VersionFile) {
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$node = $davNode->getVersion()->getSourceFile();
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$currentUserId = $this->userFolder?->getOwner()?->getUID();
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// The version source file is relative to the owner storage.
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// But we need the node from the current user perspective.
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if ($node->getOwner()->getUID() !== $currentUserId) {
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$nodes = $this->userFolder->getById($node->getId());
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$node = array_pop($nodes);
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if (!$node) {
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throw new NotFoundException('Version file not accessible by current user');
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}
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}
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} else {
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return true;
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}
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$storage = $node->getStorage();
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if (!$storage->instanceOfStorage(ISharedStorage::class)) {
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return true;
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}
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// Extract extra permissions
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/** @var ISharedStorage $storage */
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$share = $storage->getShare();
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$attributes = $share->getAttributes();
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if ($attributes === null) {
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return true;
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}
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// Check if read-only and on whether permission can download is both set and disabled.
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$canDownload = $attributes->getAttribute('permissions', 'download');
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if ($canDownload !== null && !$canDownload) {
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throw new Forbidden('Access to this shared resource has been denied because its download permission is disabled.');
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}
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} catch (NotFound $e) {
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// File not found
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}
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return true;
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}
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}
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