Files
simple-nixos-mailserver/mail-server/rspamd.nix
T
2026-04-27 12:23:04 +02:00

357 lines
11 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;
postfixCfg = config.services.postfix;
rspamdCfg = config.services.rspamd;
rspamdPkg = config.services.rspamd.package;
rspamdUser = config.services.rspamd.user;
rspamdGroup = config.services.rspamd.group;
createDkimKeypair =
{
domain,
selector,
type,
bits,
...
}:
let
privkey = "${cfg.dkim.keyDirectory}/${domain}.${selector}.key";
pubkey = "${cfg.dkim.keyDirectory}/${domain}.${selector}.txt";
in
pkgs.writeShellScript "dkim-keygen-${domain}-${selector}" ''
if [ ! -f "${privkey}" ]
then
${lib.getExe' rspamdPkg "rspamadm"} dkim_keygen ${
lib.cli.toCommandLineShellGNU { } {
inherit
domain
selector
type
bits
privkey
;
}
} > "${pubkey}"
chmod 0644 "${pubkey}"
echo "Generated key for domain ${domain} and selector ${selector}"
fi
'';
mailDomains = lib.unique (
# primary mailserver domains
config.mailserver.domains
# all dkim domains, even extra domains specified
++ lib.attrNames cfg.dkim.domains
# and the srs domain, if one is configured
++ lib.optionals (cfg.srs.domain != null) [ cfg.srs.domain ]
);
dkimKeys = lib.concatMap (
domain:
let
configuredSelectors = config.mailserver.dkim.domains.${domain}.selectors or { };
finalSelectors =
if configuredSelectors == { } then
# synthesize default dkim key, if none configured
{
"${config.mailserver.dkim.defaults.selector}" = {
keyType = null;
keyLength = null;
keyFile = null;
};
}
else
configuredSelectors;
in
lib.mapAttrsToList (selector: settings: rec {
inherit domain selector;
keyFile = settings.keyFile;
keyPath = if keyFile != null then keyFile else "${cfg.dkim.keyDirectory}/${domain}.${selector}.key";
bits =
if settings.keyLength != null then
settings.keyLength
else
config.mailserver.dkim.defaults.keyLength;
type =
if settings.keyType != null then settings.keyType else config.mailserver.dkim.defaults.keyType;
}) finalSelectors
) mailDomains;
dkimKeysToGenerate = lib.filter (key: key.keyFile == null) dkimKeys;
dkimKeysByDomain = lib.groupBy (item: item.domain) dkimKeys;
in
{
config = lib.mkIf cfg.enable {
environment.systemPackages = lib.mkBefore [
(pkgs.runCommand "rspamc-wrapped"
{
nativeBuildInputs = with pkgs; [ makeWrapper ];
}
''
makeWrapper ${lib.getExe' rspamdPkg "rspamc"} $out/bin/rspamc \
--add-flags "-h /run/rspamd/worker-controller.sock"
''
)
];
services.rspamd = {
enable = true;
debug = cfg.debug.rspamd;
locals = {
"milter_headers.conf" = {
text = ''
use = [ "authentication-results" ];
extended_spam_headers = true;
'';
};
"redis.conf" = {
text = ''
servers = "${
if cfg.redis.port == null then
cfg.redis.address
else
"${cfg.redis.address}:${toString cfg.redis.port}"
}";
''
+ (lib.optionalString (cfg.redis.password != null) ''
password = "${cfg.redis.password}";
'');
};
"classifier-bayes.conf" = {
text = ''
cache {
backend = "redis";
}
'';
};
"antivirus.conf" = lib.mkIf cfg.virusScanning {
text = ''
clamav {
action = "reject";
symbol = "CLAM_VIRUS";
type = "clamav";
log_clean = true;
servers = "/run/clamav/clamd.ctl";
scan_mime_parts = false; # scan mail as a whole unit, not parts. seems to be needed to work at all
}
'';
};
"dkim_signing.conf" = {
text = ''
enabled = ${lib.boolToString cfg.dkim.enable};
# Only sign explicitly configured domains
try_fallback = false;
# Allow for usernames w/o domain part
allow_username_mismatch = true;
# Don't normalize DKIM key selection for subdomains
use_esld = false;
domain {
${lib.concatStringsSep "\n\n" (
map (domain: ''
${domain} {
selectors [
${lib.concatStringsSep ",\n" (
map (selector: ''
{
path: "${selector.keyPath}";
selector: "${selector.selector}";
}'') dkimKeysByDomain.${domain}
)}
]
}
'') (lib.attrNames dkimKeysByDomain)
)}
}
'';
};
"dmarc.conf" = {
text = ''
${lib.optionalString cfg.dmarcReporting.enable ''
reporting {
enabled = true;
email = "noreply-dmarc@${cfg.systemDomain}";
domain = "${cfg.systemDomain}";
org_name = "${cfg.systemName}";
from_name = "${cfg.systemName}";
msgid_from = "${cfg.systemDomain}";
${lib.optionalString (cfg.dmarcReporting.excludeDomains != [ ]) ''
exclude_domains = ${builtins.toJSON cfg.dmarcReporting.excludeDomains};
''}
}''}
'';
};
};
overrides = {
"options.inc" = {
text = ''
local_addrs = [::1/128, 127.0.0.0/8]
'';
};
};
workers.rspamd_proxy = {
type = "rspamd_proxy";
bindSockets = [
{
socket = "/run/rspamd/rspamd-milter.sock";
mode = "0664";
}
];
count = 1; # Do not spawn too many processes of this type
extraConfig = ''
milter = yes; # Enable milter mode
timeout = 120s; # Needed for Milter usually
upstream "local" {
default = yes; # Self-scan upstreams are always default
self_scan = yes; # Enable self-scan
}
'';
};
workers.controller = {
type = "controller";
count = 1;
bindSockets = [
{
socket = "/run/rspamd/worker-controller.sock";
mode = "0666";
}
];
includes = [ ];
extraConfig = ''
static_dir = "''${WWWDIR}"; # Serve the web UI static assets
'';
};
};
services.redis.servers.rspamd.enable = lib.mkDefault cfg.redis.configureLocally;
systemd.tmpfiles.settings."10-rspamd.conf" = {
"${cfg.dkim.keyDirectory}" = {
d = {
# Create /var/dkim owned by rspamd user/group
user = rspamdUser;
group = rspamdGroup;
};
Z = {
# Recursively adjust permissions in /var/dkim
user = rspamdUser;
group = rspamdGroup;
};
};
};
systemd.services.rspamd = {
requires = [ "redis-rspamd.service" ] ++ (lib.optional cfg.virusScanning "clamav-daemon.service");
after = [ "redis-rspamd.service" ] ++ (lib.optional cfg.virusScanning "clamav-daemon.service");
serviceConfig = lib.mkMerge [
{
SupplementaryGroups = [ config.services.redis.servers.rspamd.group ];
}
(lib.optionalAttrs cfg.dkim.enable {
ExecStartPre = map createDkimKeypair dkimKeysToGenerate;
ReadWritePaths = [ cfg.dkim.keyDirectory ];
})
];
};
systemd.services.rspamd-dmarc-reporter = lib.optionalAttrs cfg.dmarcReporting.enable {
# Explicitly select yesterday's date to work around broken
# default behaviour when called without a date.
# https://github.com/rspamd/rspamd/issues/4062
script = toString [
(lib.getExe' rspamdPkg "rspamadm")
"dmarc_report"
"$(date -d 'yesterday' '+%Y%m%d')"
];
serviceConfig = {
User = "${config.services.rspamd.user}";
Group = "${config.services.rspamd.group}";
AmbientCapabilities = [ ];
CapabilityBoundingSet = "";
DevicePolicy = "closed";
IPAddressAllow = "localhost";
LockPersonality = true;
NoNewPrivileges = true;
PrivateDevices = true;
PrivateMounts = true;
PrivateTmp = true;
PrivateUsers = true;
ProtectClock = true;
ProtectControlGroups = true;
ProtectHome = true;
ProtectHostname = true;
ProtectKernelLogs = true;
ProtectKernelModules = true;
ProtectKernelTunables = true;
ProtectProc = "invisible";
ProcSubset = "pid";
ProtectSystem = "strict";
RemoveIPC = true;
RestrictAddressFamilies = [
"AF_INET"
"AF_INET6"
"AF_UNIX"
];
RestrictNamespaces = true;
RestrictRealtime = true;
RestrictSUIDSGID = true;
SupplementaryGroups = lib.optionals cfg.redis.configureLocally [
config.services.redis.servers.rspamd.group
];
SystemCallArchitectures = "native";
SystemCallFilter = [
"@system-service"
"~@privileged"
];
UMask = "0077";
};
};
systemd.timers.rspamd-dmarc-reporter = lib.optionalAttrs cfg.dmarcReporting.enable {
description = "Daily delivery of aggregated DMARC reports";
wantedBy = [
"timers.target"
];
timerConfig = {
OnCalendar = "daily";
Persistent = true;
RandomizedDelaySec = 86400;
FixedRandomDelay = true;
};
};
users.extraUsers.${postfixCfg.user}.extraGroups = [ rspamdCfg.group ];
};
}