nixpkgs/nixos/modules/services/networking/wg-quick.nix
Felix Uhl 57d30c7a61
nixos/wg-quick: add generatePrivateKeyFile option (#331253)
This option is already present in the wireguard module, but missing from
the wg-quick module. This is very annoying, because it means you can't
easily get a safe and valid configuration on first boot when using
wg-quick.

This change adds the same option with the same description text and the
same script, but instead of generating an entire systemd unit dedicated
to creating the key file, it adds the script as a PreUp script, which
is a much simpler solution.

I've tested this in my own configuration, and it does indeed work.
wg-quick allows multiple PreUp scripts, which are run in order, and
all PreUp scripts are run before the private key is read from disk,
see `man wg-quick`.
2024-08-03 00:07:27 +04:00

370 lines
14 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.networking.wg-quick;
kernel = config.boot.kernelPackages;
# interface options
interfaceOpts = { ... }: {
options = {
configFile = mkOption {
example = "/secret/wg0.conf";
default = null;
type = with types; nullOr str;
description = ''
wg-quick .conf file, describing the interface.
Using this option can be a useful means of configuring WireGuard if
one has an existing .conf file.
This overrides any other configuration interface configuration options.
See wg-quick manpage for more details.
'';
};
address = mkOption {
example = [ "192.168.2.1/24" ];
default = [];
type = with types; listOf str;
description = "The IP addresses of the interface.";
};
autostart = mkOption {
description = "Whether to bring up this interface automatically during boot.";
default = true;
example = false;
type = types.bool;
};
dns = mkOption {
example = [ "192.168.2.2" ];
default = [];
type = with types; listOf str;
description = "The IP addresses of DNS servers to configure.";
};
privateKey = mkOption {
example = "yAnz5TF+lXXJte14tji3zlMNq+hd2rYUIgJBgB3fBmk=";
type = with types; nullOr str;
default = null;
description = ''
Base64 private key generated by {command}`wg genkey`.
Warning: Consider using privateKeyFile instead if you do not
want to store the key in the world-readable Nix store.
'';
};
generatePrivateKeyFile = mkOption {
default = false;
type = types.bool;
description = ''
Automatically generate a private key with
{command}`wg genkey`, at the privateKeyFile location.
'';
};
privateKeyFile = mkOption {
example = "/private/wireguard_key";
type = with types; nullOr str;
default = null;
description = ''
Private key file as generated by {command}`wg genkey`.
'';
};
listenPort = mkOption {
default = null;
type = with types; nullOr int;
example = 51820;
description = ''
16-bit port for listening. Optional; if not specified,
automatically generated based on interface name.
'';
};
preUp = mkOption {
example = literalExpression ''"''${pkgs.iproute2}/bin/ip netns add foo"'';
default = "";
type = with types; coercedTo (listOf str) (concatStringsSep "\n") lines;
description = ''
Commands called at the start of the interface setup.
'';
};
preDown = mkOption {
example = literalExpression ''"''${pkgs.iproute2}/bin/ip netns del foo"'';
default = "";
type = with types; coercedTo (listOf str) (concatStringsSep "\n") lines;
description = ''
Command called before the interface is taken down.
'';
};
postUp = mkOption {
example = literalExpression ''"''${pkgs.iproute2}/bin/ip netns add foo"'';
default = "";
type = with types; coercedTo (listOf str) (concatStringsSep "\n") lines;
description = ''
Commands called after the interface setup.
'';
};
postDown = mkOption {
example = literalExpression ''"''${pkgs.iproute2}/bin/ip netns del foo"'';
default = "";
type = with types; coercedTo (listOf str) (concatStringsSep "\n") lines;
description = ''
Command called after the interface is taken down.
'';
};
table = mkOption {
example = "main";
default = null;
type = with types; nullOr str;
description = ''
The kernel routing table to add this interface's
associated routes to. Setting this is useful for e.g. policy routing
("ip rule") or virtual routing and forwarding ("ip vrf"). Both
numeric table IDs and table names (/etc/rt_tables) can be used.
Defaults to "main".
'';
};
mtu = mkOption {
example = 1248;
default = null;
type = with types; nullOr int;
description = ''
If not specified, the MTU is automatically determined
from the endpoint addresses or the system default route, which is usually
a sane choice. However, to manually specify an MTU to override this
automatic discovery, this value may be specified explicitly.
'';
};
peers = mkOption {
default = [];
description = "Peers linked to the interface.";
type = with types; listOf (submodule peerOpts);
};
};
};
# peer options
peerOpts = {
options = {
publicKey = mkOption {
example = "xTIBA5rboUvnH4htodjb6e697QjLERt1NAB4mZqp8Dg=";
type = types.str;
description = "The base64 public key to the peer.";
};
presharedKey = mkOption {
default = null;
example = "rVXs/Ni9tu3oDBLS4hOyAUAa1qTWVA3loR8eL20os3I=";
type = with types; nullOr str;
description = ''
Base64 preshared key generated by {command}`wg genpsk`.
Optional, and may be omitted. This option adds an additional layer of
symmetric-key cryptography to be mixed into the already existing
public-key cryptography, for post-quantum resistance.
Warning: Consider using presharedKeyFile instead if you do not
want to store the key in the world-readable Nix store.
'';
};
presharedKeyFile = mkOption {
default = null;
example = "/private/wireguard_psk";
type = with types; nullOr str;
description = ''
File pointing to preshared key as generated by {command}`wg genpsk`.
Optional, and may be omitted. This option adds an additional layer of
symmetric-key cryptography to be mixed into the already existing
public-key cryptography, for post-quantum resistance.
'';
};
allowedIPs = mkOption {
example = [ "10.192.122.3/32" "10.192.124.1/24" ];
type = with types; listOf str;
description = ''List of IP (v4 or v6) addresses with CIDR masks from
which this peer is allowed to send incoming traffic and to which
outgoing traffic for this peer is directed. The catch-all 0.0.0.0/0 may
be specified for matching all IPv4 addresses, and ::/0 may be specified
for matching all IPv6 addresses.'';
};
endpoint = mkOption {
default = null;
example = "demo.wireguard.io:12913";
type = with types; nullOr str;
description = ''Endpoint IP or hostname of the peer, followed by a colon,
and then a port number of the peer.'';
};
persistentKeepalive = mkOption {
default = null;
type = with types; nullOr int;
example = 25;
description = ''This is optional and is by default off, because most
users will not need it. It represents, in seconds, between 1 and 65535
inclusive, how often to send an authenticated empty packet to the peer,
for the purpose of keeping a stateful firewall or NAT mapping valid
persistently. For example, if the interface very rarely sends traffic,
but it might at anytime receive traffic from a peer, and it is behind
NAT, the interface might benefit from having a persistent keepalive
interval of 25 seconds; however, most users will not need this.'';
};
};
};
writeScriptFile = name: text: ((pkgs.writeShellScriptBin name text) + "/bin/${name}");
generatePrivateKeyScript = privateKeyFile: ''
set -e
# If the parent dir does not already exist, create it.
# Otherwise, does nothing, keeping existing permissions intact.
mkdir -p --mode 0755 "${dirOf privateKeyFile}"
if [ ! -f "${privateKeyFile}" ]; then
# Write private key file with atomically-correct permissions.
(set -e; umask 077; wg genkey > "${privateKeyFile}")
fi
'';
generateUnit = name: values:
assert assertMsg (values.configFile != null || ((values.privateKey != null) != (values.privateKeyFile != null))) "Only one of privateKey, configFile or privateKeyFile may be set";
assert assertMsg (values.generatePrivateKeyFile == false || values.privateKeyFile != null) "generatePrivateKeyFile requires privateKeyFile to be set";
let
generateKeyScriptFile = if values.generatePrivateKeyFile then writeScriptFile "generatePrivateKey.sh" (generatePrivateKeyScript values.privateKeyFile) else null;
preUpFile = if values.preUp != "" then writeScriptFile "preUp.sh" values.preUp else null;
postUp =
optional (values.privateKeyFile != null) "wg set ${name} private-key <(cat ${values.privateKeyFile})" ++
(concatMap (peer: optional (peer.presharedKeyFile != null) "wg set ${name} peer ${peer.publicKey} preshared-key <(cat ${peer.presharedKeyFile})") values.peers) ++
optional (values.postUp != "") values.postUp;
postUpFile = if postUp != [] then writeScriptFile "postUp.sh" (concatMapStringsSep "\n" (line: line) postUp) else null;
preDownFile = if values.preDown != "" then writeScriptFile "preDown.sh" values.preDown else null;
postDownFile = if values.postDown != "" then writeScriptFile "postDown.sh" values.postDown else null;
configDir = pkgs.writeTextFile {
name = "config-${name}";
executable = false;
destination = "/${name}.conf";
text =
''
[interface]
${concatMapStringsSep "\n" (address:
"Address = ${address}"
) values.address}
${concatMapStringsSep "\n" (dns:
"DNS = ${dns}"
) values.dns}
'' +
optionalString (values.table != null) "Table = ${values.table}\n" +
optionalString (values.mtu != null) "MTU = ${toString values.mtu}\n" +
optionalString (values.privateKey != null) "PrivateKey = ${values.privateKey}\n" +
optionalString (values.listenPort != null) "ListenPort = ${toString values.listenPort}\n" +
optionalString (generateKeyScriptFile != null) "PreUp = ${generateKeyScriptFile}\n" +
optionalString (preUpFile != null) "PreUp = ${preUpFile}\n" +
optionalString (postUpFile != null) "PostUp = ${postUpFile}\n" +
optionalString (preDownFile != null) "PreDown = ${preDownFile}\n" +
optionalString (postDownFile != null) "PostDown = ${postDownFile}\n" +
concatMapStringsSep "\n" (peer:
assert assertMsg (!((peer.presharedKeyFile != null) && (peer.presharedKey != null))) "Only one of presharedKey or presharedKeyFile may be set";
"[Peer]\n" +
"PublicKey = ${peer.publicKey}\n" +
optionalString (peer.presharedKey != null) "PresharedKey = ${peer.presharedKey}\n" +
optionalString (peer.endpoint != null) "Endpoint = ${peer.endpoint}\n" +
optionalString (peer.persistentKeepalive != null) "PersistentKeepalive = ${toString peer.persistentKeepalive}\n" +
optionalString (peer.allowedIPs != []) "AllowedIPs = ${concatStringsSep "," peer.allowedIPs}\n"
) values.peers;
};
configPath =
if values.configFile != null then
# This uses bind-mounted private tmp folder (/tmp/systemd-private-***)
"/tmp/${name}.conf"
else
"${configDir}/${name}.conf";
in
nameValuePair "wg-quick-${name}"
{
description = "wg-quick WireGuard Tunnel - ${name}";
requires = [ "network-online.target" ];
after = [ "network.target" "network-online.target" ];
wantedBy = optional values.autostart "multi-user.target";
environment.DEVICE = name;
path = [
pkgs.wireguard-tools
config.networking.firewall.package # iptables or nftables
config.networking.resolvconf.package # openresolv or systemd
];
serviceConfig = {
Type = "oneshot";
RemainAfterExit = true;
};
script = ''
${optionalString (!config.boot.isContainer) "${pkgs.kmod}/bin/modprobe wireguard"}
${optionalString (values.configFile != null) ''
cp ${values.configFile} ${configPath}
''}
wg-quick up ${configPath}
'';
serviceConfig = {
# Used to privately store renamed copies of external config files during activation
PrivateTmp = true;
};
preStop = ''
wg-quick down ${configPath}
'';
};
in {
###### interface
options = {
networking.wg-quick = {
interfaces = mkOption {
description = "Wireguard interfaces.";
default = {};
example = {
wg0 = {
address = [ "192.168.20.4/24" ];
privateKey = "yAnz5TF+lXXJte14tji3zlMNq+hd2rYUIgJBgB3fBmk=";
peers = [
{ allowedIPs = [ "192.168.20.1/32" ];
publicKey = "xTIBA5rboUvnH4htodjb6e697QjLERt1NAB4mZqp8Dg=";
endpoint = "demo.wireguard.io:12913"; }
];
};
};
type = with types; attrsOf (submodule interfaceOpts);
};
};
};
###### implementation
config = mkIf (cfg.interfaces != {}) {
boot.extraModulePackages = optional (versionOlder kernel.kernel.version "5.6") kernel.wireguard;
environment.systemPackages = [ pkgs.wireguard-tools ];
systemd.services = mapAttrs' generateUnit cfg.interfaces;
# Prevent networkd from clearing the rules set by wg-quick when restarted (e.g. when waking up from suspend).
systemd.network.config.networkConfig.ManageForeignRoutingPolicyRules = mkDefault false;
# WireGuard interfaces should be ignored in determining whether the network is online.
systemd.network.wait-online.ignoredInterfaces = builtins.attrNames cfg.interfaces;
};
}