diff --git a/krebs/3modules/setuid.nix b/krebs/3modules/setuid.nix
index 3ba598a45..97cf21cdd 100644
--- a/krebs/3modules/setuid.nix
+++ b/krebs/3modules/setuid.nix
@@ -21,8 +21,8 @@ let
           default = config._module.args.name;
         };
         envp = mkOption {
-          type = types.attrsOf types.str;
-          default = {};
+          type = types.nullOr (types.attrsOf types.str);
+          default = null;
         };
         filename = mkOption {
           type = mkOptionType {