nixos-mailserver/mail-server/opendkim.nix
Ero Sennin 0d9a880c0e Set DKIM policy to relaxed/relaxed
And make this policy configurable.
2021-10-14 18:45:21 +00:00

89 lines
3.5 KiB
Nix

# nixos-mailserver: a simple mail server
# Copyright (C) 2017 Brian Olsen
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>
{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.mailserver;
dkimUser = config.services.opendkim.user;
dkimGroup = config.services.opendkim.group;
createDomainDkimCert = dom:
let
dkim_key = "${cfg.dkimKeyDirectory}/${dom}.${cfg.dkimSelector}.key";
dkim_txt = "${cfg.dkimKeyDirectory}/${dom}.${cfg.dkimSelector}.txt";
in
''
if [ ! -f "${dkim_key}" ] || [ ! -f "${dkim_txt}" ]
then
${pkgs.opendkim}/bin/opendkim-genkey -s "${cfg.dkimSelector}" \
-d "${dom}" \
--bits="${toString cfg.dkimKeyBits}" \
--directory="${cfg.dkimKeyDirectory}"
mv "${cfg.dkimKeyDirectory}/${cfg.dkimSelector}.private" "${dkim_key}"
mv "${cfg.dkimKeyDirectory}/${cfg.dkimSelector}.txt" "${dkim_txt}"
echo "Generated key for domain ${dom} selector ${cfg.dkimSelector}"
fi
'';
createAllCerts = lib.concatStringsSep "\n" (map createDomainDkimCert cfg.domains);
keyTable = pkgs.writeText "opendkim-KeyTable"
(lib.concatStringsSep "\n" (lib.flip map cfg.domains
(dom: "${dom} ${dom}:${cfg.dkimSelector}:${cfg.dkimKeyDirectory}/${dom}.${cfg.dkimSelector}.key")));
signingTable = pkgs.writeText "opendkim-SigningTable"
(lib.concatStringsSep "\n" (lib.flip map cfg.domains (dom: "${dom} ${dom}")));
dkim = config.services.opendkim;
args = [ "-f" "-l" ] ++ lib.optionals (dkim.configFile != null) [ "-x" dkim.configFile ];
in
{
config = mkIf (cfg.dkimSigning && cfg.enable) {
services.opendkim = {
enable = true;
selector = cfg.dkimSelector;
keyPath = cfg.dkimKeyDirectory;
domains = "csl:${builtins.concatStringsSep "," cfg.domains}";
configFile = pkgs.writeText "opendkim.conf" (''
Canonicalization ${cfg.dkimHeaderCanonicalization}/${cfg.dkimBodyCanonicalization}
UMask 0002
Socket ${dkim.socket}
KeyTable file:${keyTable}
SigningTable file:${signingTable}
'' + (lib.optionalString cfg.debug ''
Syslog yes
SyslogSuccess yes
LogWhy yes
''));
};
users.users = optionalAttrs (config.services.postfix.user == "postfix") {
postfix.extraGroups = [ "${dkimGroup}" ];
};
systemd.services.opendkim = {
preStart = lib.mkForce createAllCerts;
serviceConfig = {
ExecStart = lib.mkForce "${pkgs.opendkim}/bin/opendkim ${escapeShellArgs args}";
PermissionsStartOnly = lib.mkForce false;
};
};
systemd.tmpfiles.rules = [
"d '${cfg.dkimKeyDirectory}' - ${dkimUser} ${dkimGroup} - -"
];
};
}