nixos/stargazer: harden systemd service

nixos/modules/services/web-servers/stargazer.nix

@@ -225,6 +225,44 @@ in
           "CAP_SETGID"
           "CAP_SETUID"
         ];
+
+        # Hardening
+        UMask = "0077";
+        PrivateTmp = true;
+        ProtectHome = true;
+        ProtectSystem = "full";
+        ProtectClock = true;
+        ProtectHostname = true;
+        ProtectControlGroups = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        ProtectProc = "invisible";
+        PrivateDevices = true;
+        NoNewPrivileges = true;
+        RestrictSUIDSGID = true;
+        PrivateMounts = true;
+        MemoryDenyWriteExecute = true;
+        LockPersonality = true;
+        RestrictRealtime = true;
+        RemoveIPC = true;
+        CapabilityBoundingSet = [
+          "~CAP_SYS_PTRACE"
+          "~CAP_SYS_ADMIN"
+          "~CAP_SETPCAP"
+          "~CAP_SYS_TIME"
+          "~CAP_SYS_PACCT"
+          "~CAP_SYS_TTY_CONFIG "
+          "~CAP_SYS_CHROOT"
+          "~CAP_SYS_BOOT"
+          "~CAP_NET_ADMIN"
+        ] ++ lib.lists.optional (!cfg.allowCgiUser) [
+          "~CAP_SETGID"
+          "~CAP_SETUID"
+        ];
+        SystemCallArchitectures = "native";
+        SystemCallFilter = [ "~@cpu-emulation @debug @keyring @mount @obsolete" ]
+          ++ lib.lists.optional (!cfg.allowCgiUser) [ "@privileged @setuid" ];
       };
     };