fix: use the correct source share for getting the max reshare permiss…

…ions

Signed-off-by: Robin Appelman <robin@icewind.nl>

lib/private/Share20/Manager.php

@@ -296,31 +296,19 @@ protected function generalCreateChecks(IShare $share, bool $isUpdate = false) {
 
 		$isFederatedShare = $share->getNode()->getStorage()->instanceOfStorage('\OCA\Files_Sharing\External\Storage');
 		$permissions = 0;
-		
+
 		$isReshare = $share->getNode()->getOwner() && $share->getNode()->getOwner()->getUID() !== $share->getSharedBy();
 		if (!$isReshare && $isUpdate) {
 			// in case of update on owner-less filesystem, we use share owner to improve reshare detection
 			$isReshare = $share->getShareOwner() !== $share->getSharedBy();
 		}
 
 		if (!$isFederatedShare && $isReshare) {
-			$userMounts = array_filter($userFolder->getById($share->getNode()->getId()), function ($mount) {
-				// We need to filter since there might be other mountpoints that contain the file
-				// e.g. if the user has access to the same external storage that the file is originating from
-				return $mount->getStorage()->instanceOfStorage(ISharedStorage::class);
-			});
-			$userMount = array_shift($userMounts);
-			if ($userMount === null) {
-				throw new GenericShareException('Could not get proper share mount for ' . $share->getNode()->getId() . '. Failing since else the next calls are called with null');
-			}
-			$mount = $userMount->getMountPoint();
-			// When it's a reshare use the parent share permissions as maximum
-			$userMountPointId = $mount->getStorageRootId();
-			$userMountPoint = $userFolder->getFirstNodeById($userMountPointId);
-
-			if ($userMountPoint === null) {
-				throw new GenericShareException('Could not get proper user mount for ' . $userMountPointId . '. Failing since else the next calls are called with null');
+			// get the root of the parent share
+			if ($userFolder->getRelativePath($share->getNode()->getPath()) === null) {
+				throw new \Exception("share node not in user folder");
 			}
+			$userMountPoint = $this->rootFolder->get($share->getNode()->getMountPoint()->getMountPoint());
 
 			/* Check if this is an incoming share */
 			$incomingShares = $this->getSharedWith($share->getSharedBy(), IShare::TYPE_USER, $userMountPoint, -1, 0);