nixpkgs/nixos/modules/services/networking/yggdrasil.nix
Emery Hemingway 0d49162aa0 nixos/yggdrasil: add group option
Allow users to access the Yggdrasil control socket by group.
2020-05-02 01:21:55 +05:30

197 lines
7.0 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.services.yggdrasil;
configProvided = (cfg.config != {});
configAsFile = (if configProvided then
toString (pkgs.writeTextFile {
name = "yggdrasil-conf";
text = builtins.toJSON cfg.config;
})
else null);
configFileProvided = (cfg.configFile != null);
generateConfig = (
if configProvided && configFileProvided then
"${pkgs.jq}/bin/jq -s add ${configAsFile} ${cfg.configFile}"
else if configProvided then
"cat ${configAsFile}"
else if configFileProvided then
"cat ${cfg.configFile}"
else
"${cfg.package}/bin/yggdrasil -genconf"
);
in {
options = with types; {
services.yggdrasil = {
enable = mkEnableOption "the yggdrasil system service";
configFile = mkOption {
type = nullOr str;
default = null;
example = "/run/keys/yggdrasil.conf";
description = ''
A file which contains JSON configuration for yggdrasil.
You do not have to supply a complete configuration, as
yggdrasil will use default values for anything which is
omitted. If the encryption and signing keys are omitted,
yggdrasil will generate new ones each time the service is
started, resulting in a random IPv6 address on the yggdrasil
network each time.
If both this option and <option>config</option> are
supplied, they will be combined, with values from
<option>config</option> taking precedence.
You can use the command <code>nix-shell -p yggdrasil --run
"yggdrasil -genconf -json"</code> to generate a default
JSON configuration.
'';
};
config = mkOption {
type = attrs;
default = {};
example = {
Peers = [
"tcp://aa.bb.cc.dd:eeeee"
"tcp://[aaaa:bbbb:cccc:dddd::eeee]:fffff"
];
Listen = [
"tcp://0.0.0.0:xxxxx"
];
};
description = ''
Configuration for yggdrasil, as a Nix attribute set.
Warning: this is stored in the WORLD-READABLE Nix store!
Therefore, it is not appropriate for private keys. If you
do not specify the keys, yggdrasil will generate a new set
each time the service is started, creating a random IPv6
address on the yggdrasil network each time.
If you wish to specify the keys, use
<option>configFile</option>. If both
<option>configFile</option> and <option>config</option> are
supplied, they will be combined, with values from
<option>config</option> taking precedence.
You can use the command <code>nix-shell -p yggdrasil --run
"yggdrasil -genconf"</code> to generate default
configuration values with documentation.
'';
};
group = mkOption {
type = types.str;
default = "root";
example = "wheel";
description =
"Group to grant acces to the Yggdrasil control socket.";
};
openMulticastPort = mkOption {
type = bool;
default = false;
description = ''
Whether to open the UDP port used for multicast peer
discovery. The NixOS firewall blocks link-local
communication, so in order to make local peering work you
will also need to set <code>LinkLocalTCPPort</code> in your
yggdrasil configuration (<option>config</option> or
<option>configFile</option>) to a port number other than 0,
and then add that port to
<option>networking.firewall.allowedTCPPorts</option>.
'';
};
denyDhcpcdInterfaces = mkOption {
type = listOf str;
default = [];
example = [ "tap*" ];
description = ''
Disable the DHCP client for any interface whose name matches
any of the shell glob patterns in this list. Use this
option to prevent the DHCP client from broadcasting requests
on the yggdrasil network. It is only necessary to do so
when yggdrasil is running in TAP mode, because TUN
interfaces do not support broadcasting.
'';
};
package = mkOption {
type = package;
default = pkgs.yggdrasil;
defaultText = "pkgs.yggdrasil";
description = "Yggdrasil package to use.";
};
};
};
config = mkIf cfg.enable {
assertions = [
{ assertion = config.networking.enableIPv6;
message = "networking.enableIPv6 must be true for yggdrasil to work";
}
];
systemd.services.yggdrasil = {
description = "Yggdrasil Network Service";
path = [ cfg.package ] ++ optional (configProvided && configFileProvided) pkgs.jq;
bindsTo = [ "network-online.target" ];
after = [ "network-online.target" ];
wantedBy = [ "multi-user.target" ];
preStart = ''
${generateConfig} | yggdrasil -normaliseconf -useconf > /run/yggdrasil/yggdrasil.conf
'';
serviceConfig = {
ExecStart = "${cfg.package}/bin/yggdrasil -useconffile /run/yggdrasil/yggdrasil.conf";
ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
Restart = "always";
Group = cfg.group;
RuntimeDirectory = "yggdrasil";
RuntimeDirectoryMode = "0750";
BindReadOnlyPaths = mkIf configFileProvided
[ "${cfg.configFile}" ];
# TODO: as of yggdrasil 0.3.8 and systemd 243, yggdrasil fails
# to set up the network adapter when DynamicUser is set. See
# github.com/yggdrasil-network/yggdrasil-go/issues/557. The
# following options are implied by DynamicUser according to
# the systemd.exec documentation, and can be removed if the
# upstream issue is fixed and DynamicUser is set to true:
PrivateTmp = true;
RemoveIPC = true;
NoNewPrivileges = true;
ProtectSystem = "strict";
RestrictSUIDSGID = true;
# End of list of options implied by DynamicUser.
AmbientCapabilities = "CAP_NET_ADMIN";
CapabilityBoundingSet = "CAP_NET_ADMIN";
MemoryDenyWriteExecute = true;
ProtectControlGroups = true;
ProtectHome = "tmpfs";
ProtectKernelModules = true;
ProtectKernelTunables = true;
RestrictAddressFamilies = "AF_UNIX AF_INET AF_INET6 AF_NETLINK";
RestrictNamespaces = true;
RestrictRealtime = true;
SystemCallArchitectures = "native";
SystemCallFilter = "~@clock @cpu-emulation @debug @keyring @module @mount @obsolete @raw-io @resources";
};
};
networking.dhcpcd.denyInterfaces = cfg.denyDhcpcdInterfaces;
networking.firewall.allowedUDPPorts = mkIf cfg.openMulticastPort [ 9001 ];
# Make yggdrasilctl available on the command line.
environment.systemPackages = [ cfg.package ];
};
meta.maintainers = with lib.maintainers; [ gazally ];
}