nixos-mailserver/mail-server/systemd.nix
Bjørn Forsman a3b03d1b5a Use umask for race-free permission setting
Without using umask there's a small time window where paths are world
readable. That is a bad idea to do for secret files (e.g. the dovecot
code path).
2023-07-17 18:22:16 +02:00

85 lines
3 KiB
Nix

# nixos-mailserver: a simple mail server
# Copyright (C) 2016-2018 Robin Raymond
#
# 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, pkgs, lib, ... }:
let
cfg = config.mailserver;
certificatesDeps =
if cfg.certificateScheme == "manual" then
[]
else if cfg.certificateScheme == "selfsigned" then
[ "mailserver-selfsigned-certificate.service" ]
else
[ "acme-finished-${cfg.fqdn}.target" ];
in
{
config = with cfg; lib.mkIf enable {
# Create self signed certificate
systemd.services.mailserver-selfsigned-certificate = lib.mkIf (cfg.certificateScheme == "selfsigned") {
after = [ "local-fs.target" ];
script = ''
# Create certificates if they do not exist yet
dir="${cfg.certificateDirectory}"
fqdn="${cfg.fqdn}"
[[ $fqdn == /* ]] && fqdn=$(< "$fqdn")
key="$dir/key-${cfg.fqdn}.pem";
cert="$dir/cert-${cfg.fqdn}.pem";
if [[ ! -f $key || ! -f $cert ]]; then
mkdir -p "${cfg.certificateDirectory}"
(umask 077; "${pkgs.openssl}/bin/openssl" genrsa -out "$key" 2048) &&
"${pkgs.openssl}/bin/openssl" req -new -key "$key" -x509 -subj "/CN=$fqdn" \
-days 3650 -out "$cert"
fi
'';
serviceConfig = {
Type = "oneshot";
PrivateTmp = true;
};
};
# Create maildir folder before dovecot startup
systemd.services.dovecot2 = {
wants = certificatesDeps;
after = certificatesDeps;
preStart = let
directories = lib.strings.escapeShellArgs (
[ mailDirectory ]
++ lib.optional (cfg.indexDir != null) cfg.indexDir
);
in ''
# Create mail directory and set permissions. See
# <http://wiki2.dovecot.org/SharedMailboxes/Permissions>.
# Prevent world-readable paths, even temporarily.
umask 007
mkdir -p ${directories}
chgrp "${vmailGroupName}" ${directories}
chmod 02770 ${directories}
'';
};
# Postfix requires dovecot lmtp socket, dovecot auth socket and certificate to work
systemd.services.postfix = {
wants = certificatesDeps;
after = [ "dovecot2.service" ]
++ lib.optional cfg.dkimSigning "opendkim.service"
++ certificatesDeps;
requires = [ "dovecot2.service" ]
++ lib.optional cfg.dkimSigning "opendkim.service";
};
};
}