fuse: verify zero padding in fuse_backing_map

To allow us extending the interface in the future.

Fixes: 44350256ab94 ("fuse: implement ioctls to manage backing files")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/fuse/passthrough.c b/fs/fuse/passthrough.c
index 1567f0323858bfce0ef4542d055c6111f936aa89..9666d13884ce59175a844f85082c442cadbdf354 100644 (file)
--- a/fs/fuse/passthrough.c
+++ b/fs/fuse/passthrough.c
@@ -225,7 +225,7 @@ int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map)
                goto out;
 
        res = -EINVAL;
-       if (map->flags)
+       if (map->flags || map->padding)
                goto out;
 
        file = fget(map->fd);