tests: Add sysctl

nixos/release-combined.nix

@@ -115,6 +115,7 @@ in rec {
         (all nixos.tests.sddm.default)
         (all nixos.tests.simple)
         (all nixos.tests.slim)
+        (all nixos.tests.sysctl)
         (all nixos.tests.udisks2)
         (all nixos.tests.xfce)
 

nixos/release.nix

@@ -309,6 +309,7 @@ in rec {
   tests.slim = callTest tests/slim.nix {};
   tests.smokeping = callTest tests/smokeping.nix {};
   tests.snapper = callTest tests/snapper.nix {};
+  tests.sysctl = callTest tests/sysctl.nix {};
   tests.taskserver = callTest tests/taskserver.nix {};
   tests.tomcat = callTest tests/tomcat.nix {};
   tests.udisks2 = callTest tests/udisks2.nix {};

nixos/tests/sysctl.nix

@@ -0,0 +1,25 @@
+import ./make-test.nix ({ pkgs, ...} : {
+  name = "sysctl";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ nequissimus ];
+  };
+
+  machine = { config, lib, pkgs, ... }:
+    {
+      boot.kernelPackages = pkgs.linuxPackages;
+      boot.kernel.sysctl = {
+        "kernel.dmesg_restrict" = true; # Restrict dmesg access
+        "net.core.bpf_jit_enable" = false; # Turn off bpf JIT
+        "user.max_user_namespaces" = 0; # Disable user namespaces
+        "vm.swappiness" = 2; # Low swap usage
+      };
+    };
+
+  testScript =
+    ''
+      $machine->succeed("sysctl kernel.dmesg_restrict | grep 'kernel.dmesg_restrict = 1'");
+      $machine->succeed("sysctl net.core.bpf_jit_enable | grep 'net.core.bpf_jit_enable = 0'");
+      $machine->succeed("sysctl user.max_user_namespaces | grep 'user.max_user_namespaces = 0'");
+      $machine->succeed("sysctl vm.swappiness | grep 'vm.swappiness = 2'");
+    '';
+})