diff --git a/overviewer_core/files.py b/overviewer_core/files.py
index 1c72661..a2017d6 100644
--- a/overviewer_core/files.py
+++ b/overviewer_core/files.py
@@ -18,6 +18,7 @@ import os.path
 import tempfile
 import shutil
 import logging
+import stat
 
 ## useful recursive copy, that ignores common OS cruft
 def mirror_dir(src, dst, entities=None):