diff --git a/nixos/modules/services/networking/nebula.nix b/nixos/modules/services/networking/nebula.nix index 35d7fafb43b5..36122d45c128 100644 --- a/nixos/modules/services/networking/nebula.nix +++ b/nixos/modules/services/networking/nebula.nix @@ -84,6 +84,28 @@ in description = "Whether this node is a relay."; }; + lighthouse.dns.enable = lib.mkOption { + type = lib.types.bool; + default = false; + description = "Whether this lighthouse node should serve DNS."; + }; + + lighthouse.dns.host = lib.mkOption { + type = lib.types.str; + default = "localhost"; + description = '' + IP address on which nebula lighthouse should serve DNS. + 'localhost' is a good default to ensure the service does not listen on public interfaces; + use a Nebula address like 10.0.0.5 to make DNS resolution available to nebula hosts only. + ''; + }; + + lighthouse.dns.port = lib.mkOption { + type = lib.types.nullOr lib.types.port; + default = 5353; + description = "UDP port number for lighthouse DNS server."; + }; + lighthouses = lib.mkOption { type = lib.types.listOf lib.types.str; default = [ ]; @@ -172,10 +194,7 @@ in ''; example = lib.literalExpression '' { - lighthouse.dns = { - host = "0.0.0.0"; - port = 53; - }; + lighthouse.interval = 15; } ''; }; @@ -203,6 +222,9 @@ in lighthouse = { am_lighthouse = netCfg.isLighthouse; hosts = netCfg.lighthouses; + serve_dns = netCfg.lighthouse.dns.enable; + dns.host = netCfg.lighthouse.dns.host; + dns.port = netCfg.lighthouse.dns.port; }; relay = { am_relay = netCfg.isRelay; @@ -231,6 +253,19 @@ in '' settings ); + capabilities = + let + nebulaPort = if !settings.tun.disabled then settings.listen.port else 0; + dnsPort = if settings.lighthouse.serve_dns then settings.lighthouse.dns.port else 0; + in + lib.concatStringsSep " " ( + # creation of tunnel interfaces + lib.optional (!settings.tun.disabled) "CAP_NET_ADMIN" + # binding to privileged ports + ++ lib.optional ( + nebulaPort > 0 && nebulaPort < 1024 || dnsPort > 0 && dnsPort < 1024 + ) "CAP_NET_BIND_SERVICE" + ); in { # Create the systemd service for Nebula. @@ -248,8 +283,8 @@ in Restart = "always"; ExecStart = "${netCfg.package}/bin/nebula -config ${configFile}"; UMask = "0027"; - CapabilityBoundingSet = "CAP_NET_ADMIN"; - AmbientCapabilities = "CAP_NET_ADMIN"; + CapabilityBoundingSet = capabilities; + AmbientCapabilities = capabilities; LockPersonality = true; NoNewPrivileges = true; PrivateDevices = false; # needs access to /dev/net/tun (below) @@ -302,5 +337,8 @@ in ); }; - meta.maintainers = with lib.maintainers; [ numinit ]; + meta.maintainers = with lib.maintainers; [ + numinit + siriobalmelli + ]; } diff --git a/nixos/tests/nebula.nix b/nixos/tests/nebula.nix index b3096424a614..68a48d4c86a2 100644 --- a/nixos/tests/nebula.nix +++ b/nixos/tests/nebula.nix @@ -14,7 +14,10 @@ import ./make-test-python.nix ( lib.mkMerge [ { # Expose nebula for doing cert signing. - environment.systemPackages = [ pkgs.nebula ]; + environment.systemPackages = [ + pkgs.dig + pkgs.nebula + ]; users.users.root.openssh.authorizedKeys.keys = [ snakeOilPublicKey ]; services.openssh.enable = true; networking.firewall.enable = true; # Implicitly true, but let's make sure. @@ -51,6 +54,7 @@ import ./make-test-python.nix ( lighthouse = { ... }@args: makeNebulaNode args "lighthouse" { + networking.firewall.allowedUDPPorts = [ 53 ]; networking.interfaces.eth1.ipv4.addresses = lib.mkForce [ { address = "192.168.1.1"; @@ -77,6 +81,13 @@ import ./make-test-python.nix ( } ]; }; + lighthouse = { + dns = { + enable = true; + host = "10.0.100.1"; # bind to lighthouse interface + port = 53; # answer on standard DNS port + }; + }; }; }; @@ -338,6 +349,8 @@ import ./make-test-python.nix ( # allowAny can ping the lighthouse, but not allowFromLighthouse because of its inbound firewall allowAny.succeed("ping -c3 10.0.100.1") allowAny.fail("ping -c3 10.0.100.3") + # allowAny can also resolve DNS on lighthouse + allowAny.succeed("dig @10.0.100.1 allowToLighthouse | grep -E 'allowToLighthouse\.\s+[0-9]+\s+IN\s+A\s+10\.0\.100\.4'") # allowFromLighthouse can ping the lighthouse and allowAny allowFromLighthouse.succeed("ping -c3 10.0.100.1")