1 files changed, 109 insertions, 0 deletions
diff --git a/nixpkgs/nixos/modules/services/networking/uptermd.nix b/nixpkgs/nixos/modules/services/networking/uptermd.nix
new file mode 100644
index 000000000000..387478de99eb
--- /dev/null
+++ b/nixpkgs/nixos/modules/services/networking/uptermd.nix
@@ -0,0 +1,109 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.uptermd;
+in
+{
+  options = {
+    services.uptermd = {
+      enable = mkEnableOption "uptermd";
+
+      openFirewall = mkOption {
+        type = types.bool;
+        default = false;
+        description = lib.mdDoc ''
+          Whether to open the firewall for the port in {option}`services.uptermd.port`.
+        '';
+      };
+
+      port = mkOption {
+        type = types.port;
+        default = 2222;
+        description = lib.mdDoc ''
+          Port the server will listen on.
+        '';
+      };
+
+      listenAddress = mkOption {
+        type = types.str;
+        default = "[::]";
+        example = "127.0.0.1";
+        description = lib.mdDoc ''
+          Address the server will listen on.
+        '';
+      };
+
+      hostKey = mkOption {
+        type = types.nullOr types.path;
+        default = null;
+        example = "/run/keys/upterm_host_ed25519_key";
+        description = lib.mdDoc ''
+          Path to SSH host key. If not defined, an ed25519 keypair is generated automatically.
+        '';
+      };
+
+      extraFlags = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        example = [ "--debug" ];
+        description = lib.mdDoc ''
+          Extra flags passed to the uptermd command.
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    networking.firewall = mkIf cfg.openFirewall {
+      allowedTCPPorts = [ cfg.port ];
+    };
+
+    systemd.services.uptermd = {
+      description = "Upterm Daemon";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+
+      path = [ pkgs.openssh ];
+
+      preStart = mkIf (cfg.hostKey == null) ''
+        if ! [ -f ssh_host_ed25519_key ]; then
+          ssh-keygen \
+            -t ed25519 \
+            -f ssh_host_ed25519_key \
+            -N ""
+        fi
+      '';
+
+      serviceConfig = {
+        StateDirectory = "uptermd";
+        WorkingDirectory = "/var/lib/uptermd";
+        ExecStart = "${pkgs.upterm}/bin/uptermd --ssh-addr ${cfg.listenAddress}:${toString cfg.port} --private-key ${if cfg.hostKey == null then "ssh_host_ed25519_key" else cfg.hostKey} ${concatStringsSep " " cfg.extraFlags}";
+
+        # Hardening
+        AmbientCapabilities = mkIf (cfg.port < 1024) [ "CAP_NET_BIND_SERVICE" ];
+        CapabilityBoundingSet = mkIf (cfg.port < 1024) [ "CAP_NET_BIND_SERVICE" ];
+        PrivateUsers = cfg.port >= 1024;
+        DynamicUser = true;
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        PrivateDevices = true;
+        ProtectClock = true;
+        ProtectControlGroups = true;
+        ProtectHome = true;
+        ProtectHostname = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        ProtectProc = "invisible";
+        # AF_UNIX is for ssh-keygen, which relies on nscd to resolve the uid to a user
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" "AF_UNIX" ];
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        SystemCallArchitectures = "native";
+        SystemCallFilter = "@system-service";
+      };
+    };
+  };
+}