fix(caldav): stricter default calendar checks

Reject calendars that
- are subscriptions
- are not writable
- are shared with a user
- are deleted
- don't support VEVENTs

Signed-off-by: Richard Steinmetz <richard@steinmetz.cloud>

1 files changed, 16 insertions, 3 deletions

diff --git a/apps/dav/lib/CalDAV/Schedule/Plugin.php b/apps/dav/lib/CalDAV/Schedule/Plugin.php
index 897901a61a4..5496fb23a96 100644
--- a/apps/dav/lib/CalDAV/Schedule/Plugin.php
+++ b/apps/dav/lib/CalDAV/Schedule/Plugin.php
@@ -9,11 +9,13 @@ use DateTimeZone;
 use OCA\DAV\CalDAV\CalDavBackend;
 use OCA\DAV\CalDAV\Calendar;
 use OCA\DAV\CalDAV\CalendarHome;
+use OCA\DAV\CalDAV\DefaultCalendarValidator;
 use OCP\IConfig;
 use Psr\Log\LoggerInterface;
 use Sabre\CalDAV\ICalendar;
 use Sabre\CalDAV\ICalendarObject;
 use Sabre\CalDAV\Schedule\ISchedulingObject;
+use Sabre\DAV\Exception as DavException;
 use Sabre\DAV\INode;
 use Sabre\DAV\IProperties;
 use Sabre\DAV\PropFind;
@@ -51,13 +53,15 @@ class Plugin extends \Sabre\CalDAV\Schedule\Plugin {
 	public const CALENDAR_USER_TYPE = '{' . self::NS_CALDAV . '}calendar-user-type';
 	public const SCHEDULE_DEFAULT_CALENDAR_URL = '{' . Plugin::NS_CALDAV . '}schedule-default-calendar-URL';
 	private LoggerInterface $logger;
+	private DefaultCalendarValidator $defaultCalendarValidator;
 
 	/**
 	 * @param IConfig $config
 	 */
-	public function __construct(IConfig $config, LoggerInterface $logger) {
+	public function __construct(IConfig $config, LoggerInterface $logger, DefaultCalendarValidator $defaultCalendarValidator) {
 		$this->config = $config;
 		$this->logger = $logger;
+		$this->defaultCalendarValidator = $defaultCalendarValidator;
 	}
 
 	/**
@@ -360,11 +364,20 @@ EOF;
 						 * - isn't a calendar subscription
 						 * - user can write to it (no virtual/3rd-party calendars)
 						 * - calendar isn't a share
+						 * - calendar supports VEVENTs
 						 */
 						foreach ($calendarHome->getChildren() as $node) {
-							if ($node instanceof Calendar && !$node->isSubscription() && $node->canWrite() && !$node->isShared() && !$node->isDeleted()) {
-								$userCalendars[] = $node;
+							if (!($node instanceof Calendar)) {
+								continue;
 							}
+
+							try {
+								$this->defaultCalendarValidator->validateScheduleDefaultCalendar($node);
+							} catch (DavException $e) {
+								continue;
+							}
+
+							$userCalendars[] = $node;
 						}
 
 						if (count($userCalendars) > 0) {