--- includes/file.inc	2010-05-17 16:09:47.000000000 -0400
+++ includes/file.inc.new	2010-05-17 16:17:42.000000000 -0400
@@ -1175,6 +1175,14 @@ function file_save_upload($source, $vali
     variable_get('upload_extensions_default', 'jpg jpeg gif png txt html doc xls pdf ppt pps odt ods odp'));
   }
 
+  // Don't munge archive extensions.
+  $archiver_info = archiver_get_info();
+  foreach ($archiver_info as $info) {
+    if (!empty($info['extensions'])) {
+      $extensions .= ' ' . implode(' ', $info['extensions']);
+    }
+  }
+
   // Begin building file object.
   $file = new stdClass();
   $file->uid      = $user->uid;