diff --git a/nix/overlay.nix b/nix/overlay.nix
index dc4b0ae7f794e5a74c0391037ee5dbd9ee73713f..27d8af3bc5a77b590c23a49c33ec0ab19e233c8d 100644
--- a/nix/overlay.nix
+++ b/nix/overlay.nix
@@ -1,3 +1,3 @@
 self: super: {
-  libchallenge_bypass_ristretto_ffi = super.callPackage ./challenge-bypass-ristretto.nix { };
+  libchallenge_bypass_ristretto_ffi = (super.callPackage ./challenge-bypass-ristretto.nix { }).lib;
 }