From 9d0c0d71309239cfdc6c19996d2b730fdf06a692 Mon Sep 17 00:00:00 2001
From: Scott Worley <scottworley@scottworley.com>
Date: Tue, 19 May 2020 21:05:08 -0700
Subject: [PATCH] Accept multiple signing keys

---
 modules/auto-upgrade.nix |  9 +++++----
 overlays/keyedgit.nix    | 15 ++++++++++-----
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/modules/auto-upgrade.nix b/modules/auto-upgrade.nix
index 8bf21aa..66d857f 100644
--- a/modules/auto-upgrade.nix
+++ b/modules/auto-upgrade.nix
@@ -28,7 +28,7 @@ let
         # Update channels
         (
           cd /etc/nixos
-          ${pkgs.keyedgit cfg.key}/bin/git pull --ff-only --verify-signatures
+          ${pkgs.keyedgit cfg.keys}/bin/git pull --ff-only --verify-signatures
           ${pkgs.pinch}/bin/pinch update channels
         )
 
@@ -71,11 +71,12 @@ in {
         '';
       };
 
-      key = mkOption {
+      keys = 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.
+          File containing GPG keys that sign updates.  Updates are only merged
+          if the commit at the tip of the remote branch is signed with one of
+          these keys.
         '';
       };
 
diff --git a/overlays/keyedgit.nix b/overlays/keyedgit.nix
index bf260e7..a4465dc 100644
--- a/overlays/keyedgit.nix
+++ b/overlays/keyedgit.nix
@@ -1,7 +1,7 @@
 # Following the instructions at https://tribut.de/blog/git-commit-signatures-trusted-keys
 
 self: super: {
-  keyedgit = key:
+  keyedgit = keys:
     let
       homelessGPG = super.writeShellScript "homeless-gpg" ''
         export GNUPGHOME=$(mktemp -d)
@@ -9,13 +9,18 @@ self: super: {
         ${self.gnupg}/bin/gpg "$@"
       '';
       keyring = super.runCommand "keyedkeyring.gpg" {} ''
-        ${homelessGPG} --no-default-keyring --keyring=$out --import ${key}
+        ${homelessGPG} --no-default-keyring --keyring=$out --import ${keys}
       '';
-      keyid = super.runCommand "keyid" {} ''
-        ${homelessGPG} --with-colons --show-keys ${key} | awk -F: '{ print $5; exit }' > $out
+      keyids = super.runCommand "keyids" {} ''
+        ${homelessGPG} --no-default-keyring --with-colons --show-keys ${keys} |
+          ${self.gawk}/bin/awk -F: 'prev == "pub" && $1 == "fpr" { print $10 } { prev = $1 }' > $out
       '';
       keyedGPG = super.writeShellScript "keyed-gpg" ''
-        ${homelessGPG} --no-default-keyring --keyring=${keyring} --trusted-key "$(< ${keyid} )" "$@"
+        trusted_key_args=()
+        while read keyid;do
+          trusted_key_args+=( --trusted-key "$keyid" )
+        done < ${keyids}
+        ${homelessGPG} --no-default-keyring --keyring=${keyring} "''${trusted_key_args[@]}" "$@"
       '';
     in super.symlinkJoin {
       name = "keyedgit";
-- 
2.44.1