nixos: Working ACME certs

nixos/boxes/colony/vms/estuary/default.nix

@@ -176,7 +176,7 @@
                   }
                   table inet nat {
                     chain prerouting {
-                      iifname wan meta l4proto { udp, tcp } th dport domain redirect to :5353
+                      ${matchInet "meta l4proto { udp, tcp } th dport domain redirect to :5353" "estuary"}
                     }
                     chain postrouting {
                       ip saddr ${lib.my.colony.prefixes.all.v4} masquerade

nixos/boxes/colony/vms/estuary/dns.nix

@@ -13,14 +13,14 @@ let
 
   pdns-file-record = pkgs.writeShellApplication {
     name = "pdns-file-record";
-    runtimeInputs = [ pkgs.gnused ];
+    runtimeInputs = with pkgs; [ gnused pdns ];
     text = ''
       die() {
         echo "$@" >&2
         exit 1
       }
       usage() {
-        die "usage: $0 <add|del> <fqdn> [content]"
+        die "usage: $0 <zone> <add|del> <fqdn> [content]"
       }
 
       add() {
@@ -47,11 +47,14 @@ let
       dir=/run/pdns/file-records
       mkdir -p "$dir"
 
-      if [ $# -lt 1 ]; then
+      if [ $# -lt 2 ]; then
         usage
       fi
+      zone="$1"
+      shift
       cmd="$1"
       shift
+
       case "$cmd" in
       add)
         add "$@";;
@@ -60,11 +63,48 @@ let
       *)
         usage;;
       esac
+
+      # TODO: This feels pretty hacky?
+      zDat=/var/lib/pdns/bind-zones/"$zone".dat
+      # shellcheck disable=SC1090
+      source "$zDat"
+      ((serial++))
+      sed -i "s/^serial=.*$/serial=$serial/g" "$zDat"
+      sed "s/@@SERIAL@@/$serial/g" < /etc/pdns/bind-zones/"$zone".zone > /run/pdns/bind-zones/"$zone".zone
+      pdns_control bind-reload-now "$zone"
     '';
   };
 in
 {
   config = {
+    users = {
+      users = {
+        "pdns-file-records" =
+        let
+          script = pkgs.writeShellScript "pdns-file-records-ssh.sh" ''
+            read -r -a args <<< "$SSH_ORIGINAL_COMMAND"
+            exec ${pdns-file-record}/bin/pdns-file-record "''${args[@]}"
+          '';
+        in
+        {
+          group = "pdns";
+          isSystemUser = true;
+          shell = pkgs.bashInteractive;
+          openssh.authorizedKeys.keys = [
+            ''command="${script}" ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIBSvcgbEesOgvKJLt3FLXPaLOcCIuOUYtZXXtEv6k4Yd''
+          ];
+        };
+      };
+    };
+
+    systemd = {
+      services = {
+        pdns.preStart = ''
+          install -d -m 775 /run/pdns/file-records
+        '';
+      };
+    };
+
     services.pdns-recursor = {
       enable = true;
       dns = {
@@ -164,7 +204,7 @@ in
         wildcardPtr6Z = wildcardPtr6 ptrDots6;
 
         fileRecScript = pkgs.writeText "file-record.lua" ''
-          local path = "/run/pdns/file-records/" .. qname:toStringNoDot() .. ".txt"
+          local path = "/run/pdns/file-records/" .. string.lower(qname:toStringNoDot()) .. ".txt"
           if not os.execute("test -e " .. path) then
             return {}
           end
@@ -195,8 +235,10 @@ in
 
             @ IN ALIAS ${config.networking.fqdn}.
 
+            $TTL 3
             _acme-challenge IN LUA TXT ${fileRecVal}
 
+            $TTL 60
             ${intRecords}
           '';
         };

nixos/boxes/colony/vms/shill/containers/middleman.nix

@@ -16,7 +16,7 @@
       };
     };
 
-    configuration = { lib, config, assignments, allAssignments, ... }:
+    configuration = { lib, pkgs, config, assignments, allAssignments, ... }:
     let
       inherit (lib) mkMerge mkIf;
       inherit (lib.my) networkdAssignment;
@@ -29,7 +29,13 @@
 
             secrets = {
               key = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIAuvP9DEsffop53Fsh7xIdeVyQSF6tSKrOUs2faq6rip";
-              files."dhparams.pem" = {};
+              files = {
+                "dhparams.pem" = {};
+                "pdns-file-records.key" = {
+                  owner = "acme";
+                  group = "acme";
+                };
+              };
             };
 
             firewall = {
@@ -44,6 +50,51 @@
             network.networks."80-container-host0" = networkdAssignment "host0" assignments.internal;
           };
 
+          security = {
+            acme = {
+              acceptTerms = true;
+              defaults = {
+                email = "dev@nul.ie";
+                server = "https://acme-staging-v02.api.letsencrypt.org/directory";
+                reloadServices = [ "nginx" ];
+                dnsResolver = "8.8.8.8";
+              };
+
+              certs = {
+                "${config.networking.domain}" = {
+                  extraDomainNames = [
+                    "*.${config.networking.domain}"
+                  ];
+                  dnsProvider = "exec";
+                  credentialsFile =
+                  let
+                    script = pkgs.writeShellScript "lego-update-int.sh" ''
+                      case "$1" in
+                      present)
+                        cmd=add;;
+                      cleanup)
+                        cmd=del;;
+                      *)
+                        exit 1;;
+                      esac
+
+                      echo "$@"
+                      exec ${pkgs.openssh}/bin/ssh \
+                        -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no \
+                        -i ${config.age.secrets."pdns-file-records.key".path} \
+                        pdns-file-records@estuary-vm "${config.networking.domain}" "$cmd" "$2" "$3"
+                    '';
+                  in
+                  pkgs.writeText "lego-exec-vars.conf" ''
+                    EXEC_PROPAGATION_TIMEOUT=60
+                    EXEC_POLLING_INTERVAL=2
+                    EXEC_PATH=${script}
+                  '';
+                };
+              };
+            };
+          };
+
           services = {
             nginx = {
               enable = true;