1 files changed, 133 insertions, 0 deletions
diff --git a/nixos/modules/services/misc/mollysocket.nix b/nixos/modules/services/misc/mollysocket.nix
new file mode 100644
index 000000000000..f40caa4a782e
--- /dev/null
+++ b/nixos/modules/services/misc/mollysocket.nix
@@ -0,0 +1,133 @@
+{ config, lib, pkgs, ... }:
+
+let
+  inherit (lib) getExe mkIf mkOption mkEnableOption optionals types;
+
+  cfg = config.services.mollysocket;
+  configuration = format.generate "mollysocket.conf" cfg.settings;
+  format = pkgs.formats.toml { };
+  package = pkgs.writeShellScriptBin "mollysocket" ''
+    MOLLY_CONF=${configuration} exec ${getExe pkgs.mollysocket} "$@"
+  '';
+in {
+  options.services.mollysocket = {
+    enable = mkEnableOption ''
+      [MollySocket](https://github.com/mollyim/mollysocket) for getting Signal
+      notifications via UnifiedPush
+    '';
+
+    settings = mkOption {
+      default = { };
+      description = ''
+        Configuration for MollySocket. Available options are listed
+        [here](https://github.com/mollyim/mollysocket#configuration).
+      '';
+      type = types.submodule {
+        freeformType = format.type;
+        options = {
+          host = mkOption {
+            default = "127.0.0.1";
+            description = "Listening address of the web server";
+            type = types.str;
+          };
+
+          port = mkOption {
+            default = 8020;
+            description = "Listening port of the web server";
+            type = types.port;
+          };
+
+          allowed_endpoints = mkOption {
+            default = [ "*" ];
+            description = "List of UnifiedPush servers";
+            example = [ "https://ntfy.sh" ];
+            type = with types; listOf str;
+          };
+
+          allowed_uuids = mkOption {
+            default = [ "*" ];
+            description = "UUIDs of Signal accounts that may use this server";
+            example = [ "abcdef-12345-tuxyz-67890" ];
+            type = with types; listOf str;
+          };
+        };
+      };
+    };
+
+    environmentFile = mkOption {
+      default = null;
+      description = ''
+        Environment file (see {manpage}`systemd.exec(5)` "EnvironmentFile="
+        section for the syntax) passed to the service. This option can be
+        used to safely include secrets in the configuration.
+      '';
+      example = "/run/secrets/mollysocket";
+      type = with types; nullOr path;
+    };
+
+    logLevel = mkOption {
+      default = "info";
+      description = "Set the {env}`RUST_LOG` environment variable";
+      example = "debug";
+      type = types.str;
+    };
+  };
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = [
+      package
+    ];
+
+    # see https://github.com/mollyim/mollysocket/blob/main/mollysocket.service
+    systemd.services.mollysocket = {
+      description = "MollySocket";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network-online.target" ];
+      wants = [ "network-online.target" ];
+      environment.RUST_LOG = cfg.logLevel;
+      serviceConfig = let
+        capabilities = [ "" ] ++ optionals (cfg.settings.port < 1024) [ "CAP_NET_BIND_SERVICE" ];
+      in {
+        EnvironmentFile = cfg.environmentFile;
+        ExecStart = "${getExe package} server";
+        KillSignal = "SIGINT";
+        Restart = "on-failure";
+        StateDirectory = "mollysocket";
+        TimeoutStopSec = 5;
+        WorkingDirectory = "/var/lib/mollysocket";
+
+        # hardening
+        AmbientCapabilities = capabilities;
+        CapabilityBoundingSet = capabilities;
+        DevicePolicy = "closed";
+        DynamicUser = true;
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        NoNewPrivileges = true;
+        PrivateDevices = true;
+        PrivateTmp = true;
+        PrivateUsers = true;
+        ProcSubset = "pid";
+        ProtectClock = true;
+        ProtectControlGroups = true;
+        ProtectHome = true;
+        ProtectHostname = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        ProtectProc = "invisible";
+        ProtectSystem = "strict";
+        RemoveIPC = true;
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" ];
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+        SystemCallArchitectures = "native";
+        SystemCallFilter = [ "@system-service" "~@resources" "~@privileged" ];
+        UMask = "0077";
+      };
+    };
+  };
+
+  meta.maintainers = with lib.maintainers; [ dotlambda ];
+}