1 files changed, 58 insertions, 0 deletions
diff --git a/nixos/modules/security/lock-kernel-modules.nix b/nixos/modules/security/lock-kernel-modules.nix
new file mode 100644
index 00000000000..065587bc286
--- /dev/null
+++ b/nixos/modules/security/lock-kernel-modules.nix
@@ -0,0 +1,58 @@
+{ config, pkgs, lib, ... }:
+
+with lib;
+
+{
+  meta = {
+    maintainers = [ maintainers.joachifm ];
+  };
+
+  options = {
+    security.lockKernelModules = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Disable kernel module loading once the system is fully initialised.
+        Module loading is disabled until the next reboot. Problems caused
+        by delayed module loading can be fixed by adding the module(s) in
+        question to <option>boot.kernelModules</option>.
+      '';
+    };
+  };
+
+  config = mkIf config.security.lockKernelModules {
+    boot.kernelModules = concatMap (x:
+      if x.device != null
+        then
+          if x.fsType == "vfat"
+            then [ "vfat" "nls-cp437" "nls-iso8859-1" ]
+            else [ x.fsType ]
+        else []) config.system.build.fileSystems;
+
+    systemd.services.disable-kernel-module-loading = {
+      description = "Disable kernel module loading";
+
+      wants = [ "systemd-udevd.service" ];
+      wantedBy = [ config.systemd.defaultUnit ];
+
+      after =
+        [ "firewall.service"
+          "systemd-modules-load.service"
+           config.systemd.defaultUnit
+        ];
+
+      unitConfig.ConditionPathIsReadWrite = "/proc/sys/kernel";
+
+      serviceConfig =
+        { Type = "oneshot";
+          RemainAfterExit = true;
+          TimeoutSec = 180;
+        };
+
+      script = ''
+        ${pkgs.udev}/bin/udevadm settle
+        echo -n 1 >/proc/sys/kernel/modules_disabled
+      '';
+    };
+  };
+}