config/modules/services/nsd-acme/default.nix

213 lines
6.1 KiB
Nix

{
config,
lib,
pkgs,
...
}: let
cfg = config.mj.services.nsd-acme;
mkHook = zone: let
rc = config.services.nsd.remoteControl;
fullZone = "_acme-endpoint.${zone}";
in
pkgs.writeShellScript "nsd-acme-hook" ''
set -euo pipefail
METHOD=$1
TYPE=$2
AUTH=$5
NOW=$(date +%y%m%d%H%M)
DIR="/var/lib/nsd/acmezones"
[ "$TYPE" != "dns-01" ] && { exit 1; }
write_zone() {
cat <<EOF
\$ORIGIN ${fullZone}.
\$TTL 60
@ SOA ${fullZone}. motiejus.jakstys.lt. ($NOW 12h 2h 2w 1h)
@ TXT $AUTH
EOF
}
cleanup() {
nsd-control delzone ${fullZone}
rm -f "$DIR/${fullZone}.zone"
}
mkdir -p "$DIR"
case "$METHOD" in
begin)
nsd-control delzone ${fullZone} || :
write_zone > "$DIR/${fullZone}.zone"
nsd-control addzone ${fullZone} acme
;;
done)
cleanup
;;
failed)
cleanup
;;
esac
'';
in {
options.mj.services.nsd-acme = with lib.types; {
enable = lib.mkEnableOption "enable acme certs via nsd";
zones = lib.mkOption {
default = {};
type = attrsOf (submodule (
{name, ...}: {
options = {
accountKey = lib.mkOption {type = path;};
days = lib.mkOption {
type = int;
default = 30;
};
staging = lib.mkOption {
type = bool;
default = false;
};
# Warning: paths here are here to be read from. Changing them will
# not place the files somewhere else.
certFile = lib.mkOption {
type = str;
default = "/var/lib/nsd-acme/${name}/${name}/cert.pem";
};
keyFile = lib.mkOption {
type = str;
default = "/var/lib/nsd-acme/${name}/private/${name}/key.pem";
};
};
}
));
};
};
# TODO assert services.nsd.enable
config = lib.mkIf cfg.enable {
services.nsd.remoteControl.enable = true;
services.nsd.extraConfig = ''
pattern:
name: "acme"
zonefile: "/var/lib/nsd/acmezones/%s.zone"
'';
systemd.tmpfiles.rules = ["d /var/lib/nsd/acmezones 0755 nsd nsd -"];
systemd.services =
{
nsd-control-setup = {
requiredBy = ["nsd.service"];
before = ["nsd.service"];
unitConfig.ConditionPathExists = let
rc = config.services.nsd.remoteControl;
in [
"|!${rc.controlKeyFile}"
"|!${rc.controlCertFile}"
"|!${rc.serverKeyFile}"
"|!${rc.serverCertFile}"
];
serviceConfig = {
Type = "oneshot";
UMask = 0077;
};
script = ''
${pkgs.nsd}/bin/nsd-control-setup
chown nsd:nsd /etc/nsd/nsd_{control,server}.{key,pem}
'';
path = [pkgs.openssl];
};
}
// lib.mapAttrs'
(
zone: cfg:
lib.nameValuePair "nsd-acme-${zone}" {
description = "dns-01 acme update for ${zone}";
path = [pkgs.openssh pkgs.nsd];
preStart = ''
mkdir -p "$STATE_DIRECTORY/private"
ln -sf "$CREDENTIALS_DIRECTORY/letsencrypt-account-key" \
"$STATE_DIRECTORY/private/key.pem"
'';
serviceConfig = {
ExecStart = let
hook = mkHook zone;
days = builtins.toString cfg.days;
staging = lib.optionalString cfg.staging "--staging";
in "${pkgs.uacme}/bin/uacme -c \${STATE_DIRECTORY} --verbose --days ${days} --hook ${hook} ${staging} issue ${zone}";
UMask = "0022";
User = "nsd";
Group = "nsd";
StateDirectory = "nsd-acme/${zone}";
LoadCredential = ["letsencrypt-account-key:${cfg.accountKey}"];
ReadWritePaths = ["/var/lib/nsd/acmezones"];
SuccessExitStatus = [0 1];
# from nixos/modules/security/acme/default.nix
ProtectSystem = "strict";
PrivateTmp = true;
CapabilityBoundingSet = [""];
DevicePolicy = "closed";
LockPersonality = true;
MemoryDenyWriteExecute = true;
NoNewPrivileges = true;
PrivateDevices = true;
ProtectClock = true;
ProtectHome = true;
ProtectHostname = true;
ProtectControlGroups = true;
ProtectKernelLogs = true;
ProtectKernelModules = true;
ProtectKernelTunables = true;
ProtectProc = "invisible";
ProcSubset = "pid";
RemoveIPC = true;
# "cannot get devices"
#RestrictAddressFamilies = [
# "AF_INET"
# "AF_INET6"
#];
RestrictNamespaces = true;
RestrictRealtime = true;
RestrictSUIDSGID = true;
SystemCallArchitectures = "native";
SystemCallFilter = [
# 1. allow a reasonable set of syscalls
"@system-service @resources"
# 2. and deny unreasonable ones
"~@privileged"
# 3. then allow the required subset within denied groups
"@chown"
];
};
}
)
cfg.zones;
systemd.timers =
lib.mapAttrs'
(
zone: cfg:
lib.nameValuePair "nsd-acme-${zone}" {
description = "nsd-acme for zone ${zone}";
wantedBy = ["timers.target"];
timerConfig = {
OnCalendar = "*-*-* 01:30";
};
after = ["network-online.target"];
}
)
cfg.zones;
mj.base.unitstatus.units =
lib.mkIf config.mj.base.unitstatus.enable
(
["nsd-control-setup"]
++ map (z: "nsd-acme-${z}")
(lib.attrNames cfg.zones)
);
};
}