From d8537205b9696e3b76bc8cad98966e52f1ab626f Mon Sep 17 00:00:00 2001
From: Scott Worley <scottworley@scottworley.com>
Date: Tue, 14 Apr 2020 16:24:02 -0700
Subject: [PATCH] Require signatures to pull updates

---
 modules/auto-upgrade.nix | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/modules/auto-upgrade.nix b/modules/auto-upgrade.nix
index 973ac22..1facaba 100644
--- a/modules/auto-upgrade.nix
+++ b/modules/auto-upgrade.nix
@@ -25,11 +25,22 @@ in {
           which the update will occur.
         '';
       };
+
+      key = mkOption {
+        type = types.path;
+        description = ''
+          GPG key that signs updates.  Updates are only merged if the commit
+          at the tip of the remote branch is signed with this key.
+        '';
+      };
     };
   };
 
   config = lib.mkIf cfg.enable {
-    nixpkgs.overlays = [ (import ../overlays/pinch.nix) ];
+    nixpkgs.overlays = [
+      (import ../overlays/keyedgit.nix)
+      (import ../overlays/pinch.nix)
+    ];
     systemd.services.nixos-upgrade = {
       description = "NixOS Upgrade";
       restartIfChanged = false;
@@ -55,7 +66,7 @@ in {
         set -e
         (
           cd /etc/nixos
-          git pull --ff-only
+          ${pkgs.keyedgit cfg.key}/bin/git pull --ff-only --verify-signatures
           pinch update channels
         )
 
-- 
2.44.1