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<?php
/**
* SPDX-FileCopyrightText: 2016-2024 Nextcloud GmbH and Nextcloud contributors
* SPDX-FileCopyrightText: 2016 ownCloud, Inc.
* SPDX-License-Identifier: AGPL-3.0-only
*/
namespace OCA\DAV\Connector\Sabre;
use OCA\DAV\CalDAV\CachedSubscription;
use OCA\DAV\CalDAV\Calendar;
use OCA\DAV\CardDAV\AddressBook;
use Sabre\CalDAV\Principal\User;
use Sabre\DAV\Exception\Forbidden;
use Sabre\DAV\Exception\NotFound;
use Sabre\DAV\INode;
use Sabre\DAV\PropFind;
use Sabre\HTTP\RequestInterface;
use Sabre\HTTP\ResponseInterface;
/**
* Class DavAclPlugin is a wrapper around \Sabre\DAVACL\Plugin that returns 404
* responses in case the resource to a response has been forbidden instead of
* a 403. This is used to prevent enumeration of valid resources.
*
* @see https://github.com/owncloud/core/issues/22578
* @package OCA\DAV\Connector\Sabre
*/
class DavAclPlugin extends \Sabre\DAVACL\Plugin {
public function __construct() {
$this->hideNodesFromListings = true;
$this->allowUnauthenticatedAccess = false;
}
public function checkPrivileges($uri, $privileges, $recursion = self::R_PARENT, $throwExceptions = true) {
$access = parent::checkPrivileges($uri, $privileges, $recursion, false);
if ($access === false && $throwExceptions) {
/** @var INode $node */
$node = $this->server->tree->getNodeForPath($uri);
switch (get_class($node)) {
case AddressBook::class:
$type = 'Addressbook';
break;
case Calendar::class:
case CachedSubscription::class:
$type = 'Calendar';
break;
default:
$type = 'Node';
break;
}
if ($this->getCurrentUserPrincipal() === $node->getOwner()) {
throw new Forbidden("Access denied");
} else {
throw new NotFound(
sprintf(
"%s with name '%s' could not be found",
$type,
$node->getName()
)
);
}
}
return $access;
}
public function propFind(PropFind $propFind, INode $node) {
if ($node instanceof Node) {
// files don't use dav acls
return;
}
// If the node is neither readable nor writable then fail unless its of
// the standard user-principal
if (!($node instanceof User)) {
$path = $propFind->getPath();
$readPermissions = $this->checkPrivileges($path, '{DAV:}read', self::R_PARENT, false);
$writePermissions = $this->checkPrivileges($path, '{DAV:}write', self::R_PARENT, false);
if ($readPermissions === false && $writePermissions === false) {
$this->checkPrivileges($path, '{DAV:}read', self::R_PARENT, true);
$this->checkPrivileges($path, '{DAV:}write', self::R_PARENT, true);
}
}
return parent::propFind($propFind, $node);
}
public function beforeMethod(RequestInterface $request, ResponseInterface $response) {
$path = $request->getPath();
// prevent the plugin from causing an unneeded overhead for file requests
if (str_starts_with($path, 'files/')) {
return;
}
parent::beforeMethod($request, $response);
if (!str_starts_with($path, 'addressbooks/') && !str_starts_with($path, 'calendars/')) {
return;
}
[$parentName] = \Sabre\Uri\split($path);
if ($request->getMethod() === 'REPORT') {
// is calendars/users/bob or addressbooks/users/bob readable?
$this->checkPrivileges($parentName, '{DAV:}read');
} elseif ($request->getMethod() === 'MKCALENDAR' || $request->getMethod() === 'MKCOL') {
// is calendars/users/bob or addressbooks/users/bob writeable?
$this->checkPrivileges($parentName, '{DAV:}write');
}
}
}
|
