path: root/modules/private/mail/milters.nix

{ lib, pkgs, config, ... }:
{
  options.myServices.mail.milters.sockets = lib.mkOption {
    type = lib.types.attrsOf lib.types.path;
    default = {
      opendkim = "/run/opendkim/opendkim.sock";
      opendmarc = "/run/opendmarc/opendmarc.sock";
      openarc = "/run/openarc/openarc.sock";
    };
    readOnly = true;
    description = ''
      milters sockets
      '';
  };
  config = lib.mkIf (config.myServices.mail.enable || config.myServices.mailBackup.enable) {
    secrets.keys = [
      {
        dest = "opendkim/eldiron.private";
        user = config.services.opendkim.user;
        group = config.services.opendkim.group;
        permissions = "0400";
        text = config.myEnv.mail.dkim.eldiron.private;
      }
      {
        dest = "opendkim/eldiron.txt";
        user = config.services.opendkim.user;
        group = config.services.opendkim.group;
        permissions = "0444";
        text = ''
          eldiron._domainkey	IN	TXT	${config.myEnv.mail.dkim.eldiron.public}'';
      }
      {
        dest = "opendmarc/ignore.hosts";
        user = config.services.opendmarc.user;
        group = config.services.opendmarc.group;
        permissions = "0400";
        text = let
          mxes = lib.attrsets.filterAttrs
            (n: v: v.mx.enable)
            config.myEnv.servers;
          in
            builtins.concatStringsSep "\n" ([
              config.myEnv.mail.dmarc.ignore_hosts
            ] ++ lib.mapAttrsToList (n: v: v.fqdn) mxes);
      }
    ];
    users.users."${config.services.opendkim.user}".extraGroups = [ "keys" ];
    services.opendkim = {
      enable = true;
      socket = "local:${config.myServices.mail.milters.sockets.opendkim}";
      domains = builtins.concatStringsSep "," (lib.flatten (map
        (zone: map
          (e: "${e.domain}${lib.optionalString (e.domain != "") "."}${zone.name}")
          (zone.withEmail or [])
        )
        config.myEnv.dns.masterZones
      ));
      keyPath = "${config.secrets.location}/opendkim";
      selector = "eldiron";
      configFile = pkgs.writeText "opendkim.conf" ''
        SubDomains        yes
        UMask             002
        AlwaysAddARHeader yes
        '';
      group = config.services.postfix.group;
    };
    systemd.services.opendkim.preStart = lib.mkBefore ''
      # Skip the prestart script as keys are handled in secrets
      exit 0
      '';
    services.filesWatcher.opendkim = {
      restart = true;
      paths = [
        config.secrets.fullPaths."opendkim/eldiron.private"
      ];
    };

    users.users."${config.services.opendmarc.user}".extraGroups = [ "keys" ];
    services.opendmarc = {
      enable = true;
      socket = "local:${config.myServices.mail.milters.sockets.opendmarc}";
      configFile = pkgs.writeText "opendmarc.conf" ''
        AuthservID                  HOSTNAME
        FailureReports              false
        FailureReportsBcc           postmaster@immae.eu
        FailureReportsOnNone        true
        FailureReportsSentBy        postmaster@immae.eu
        IgnoreAuthenticatedClients  true
        IgnoreHosts                 ${config.secrets.fullPaths."opendmarc/ignore.hosts"}
        SoftwareHeader              true
        SPFIgnoreResults            true
        SPFSelfValidate             true
        UMask                       002
        '';
      group = config.services.postfix.group;
    };
    services.filesWatcher.opendmarc = {
      restart = true;
      paths = [
        config.secrets.fullPaths."opendmarc/ignore.hosts"
      ];
    };

    services.openarc = {
      enable = true;
      user = "opendkim";
      socket = "local:${config.myServices.mail.milters.sockets.openarc}";
      group = config.services.postfix.group;
      configFile = pkgs.writeText "openarc.conf" ''
        AuthservID              mail.immae.eu
        Domain                  mail.immae.eu
        KeyFile                 ${config.secrets.fullPaths."opendkim/eldiron.private"}
        Mode                    sv
        Selector                eldiron
        SoftwareHeader          yes
        Syslog                  Yes
        '';
    };
    systemd.services.openarc.postStart = lib.optionalString
          (lib.strings.hasPrefix "local:" config.services.openarc.socket) ''
      while [ ! -S ${lib.strings.removePrefix "local:" config.services.openarc.socket} ]; do
        sleep 0.5
      done
      chmod g+w ${lib.strings.removePrefix "local:" config.services.openarc.socket}
      '';
    services.filesWatcher.openarc = {
      restart = true;
      paths = [
        config.secrets.fullPaths."opendkim/eldiron.private"
      ];
    };

    systemd.services.milter_verify_from = {
      description  = "Verify from milter";
      after = [ "network.target" ];
      wantedBy = [ "multi-user.target" ];

      serviceConfig = {
        User = "postfix";
        Group = "postfix";
        ExecStart = let python = pkgs.python3.withPackages (p: [ p.pymilter ]);
          in "${python}/bin/python ${./verify_from.py} -s /run/milter_verify_from/verify_from.sock";
        RuntimeDirectory = "milter_verify_from";
      };
    };
  };
}