diff -r d9cdfaf9ac04 Lib/tarfile.py
--- a/Lib/tarfile.py	Mon Mar 24 09:06:33 2014 +0100
+++ b/Lib/tarfile.py	Mon Mar 24 12:54:17 2014 +0100
@@ -1423,7 +1423,8 @@
             fileobj = bltn_open(name, self._mode)
             self._extfileobj = False
         else:
-            if name is None and hasattr(fileobj, "name"):
+            if (name is None and hasattr(fileobj, "name") and
+                isinstance(fileobj.name, (str, bytes))):
                 name = fileobj.name
             if hasattr(fileobj, "mode"):
                 self._mode = fileobj.mode