linux: remove canDisableNetfilterConntrackHelpers feature

This feature is available in all kernels in nixpkgs.

nixos/modules/services/networking/firewall.nix

@@ -41,7 +41,6 @@ let
   kernelPackages = config.boot.kernelPackages;
 
   kernelHasRPFilter = kernelPackages.kernel.features.netfilterRPFilter or false;
-  kernelCanDisableHelpers = kernelPackages.kernel.features.canDisableNetfilterConntrackHelpers or false;
 
   helpers =
     ''
@@ -512,8 +511,6 @@ in
 
     assertions = [ { assertion = (cfg.checkReversePath != false) || kernelHasRPFilter;
                      message = "This kernel does not support rpfilter"; }
-                   { assertion = cfg.autoLoadConntrackHelpers || kernelCanDisableHelpers;
-                     message = "This kernel does not support disabling conntrack helpers"; }
                  ];
 
     systemd.services.firewall = {

pkgs/os-specific/linux/kernel/linux-3.10.nix

@@ -14,6 +14,5 @@ import ./generic.nix (args // rec {
   features.iwlwifi = true;
   features.efiBootStub = true;
   features.needsCifsUtils = true;
-  features.canDisableNetfilterConntrackHelpers = true;
   features.netfilterRPFilter = true;
 })

pkgs/os-specific/linux/kernel/linux-3.12.nix

@@ -14,6 +14,5 @@ import ./generic.nix (args // rec {
   features.iwlwifi = true;
   features.efiBootStub = true;
   features.needsCifsUtils = true;
-  features.canDisableNetfilterConntrackHelpers = true;
   features.netfilterRPFilter = true;
 })

pkgs/os-specific/linux/kernel/linux-3.18.nix

@@ -14,6 +14,5 @@ import ./generic.nix (args // rec {
   features.iwlwifi = true;
   features.efiBootStub = true;
   features.needsCifsUtils = true;
-  features.canDisableNetfilterConntrackHelpers = true;
   features.netfilterRPFilter = true;
 } // (args.argsOverride or {}))

pkgs/os-specific/linux/kernel/linux-4.1.nix

@@ -14,6 +14,5 @@ import ./generic.nix (args // rec {
   features.iwlwifi = true;
   features.efiBootStub = true;
   features.needsCifsUtils = true;
-  features.canDisableNetfilterConntrackHelpers = true;
   features.netfilterRPFilter = true;
 } // (args.argsOverride or {}))

pkgs/os-specific/linux/kernel/linux-4.4.nix

@@ -14,6 +14,5 @@ import ./generic.nix (args // rec {
   features.iwlwifi = true;
   features.efiBootStub = true;
   features.needsCifsUtils = true;
-  features.canDisableNetfilterConntrackHelpers = true;
   features.netfilterRPFilter = true;
 } // (args.argsOverride or {}))

pkgs/os-specific/linux/kernel/linux-4.9.nix

@@ -14,6 +14,5 @@ import ./generic.nix (args // rec {
   features.iwlwifi = true;
   features.efiBootStub = true;
   features.needsCifsUtils = true;
-  features.canDisableNetfilterConntrackHelpers = true;
   features.netfilterRPFilter = true;
 } // (args.argsOverride or {}))

pkgs/os-specific/linux/kernel/linux-chromiumos-3.14.nix

@@ -16,7 +16,6 @@ import ./generic.nix (args // rec {
   features.iwlwifi = true;
   features.efiBootStub = true;
   features.needsCifsUtils = true;
-  features.canDisableNetfilterConntrackHelpers = true;
   features.netfilterRPFilter = true;
   features.chromiumos = true;
 } // (args.argsOverride or {}))

pkgs/os-specific/linux/kernel/linux-chromiumos-3.18.nix

@@ -16,7 +16,6 @@ import ./generic.nix (args // rec {
   features.iwlwifi = true;
   features.efiBootStub = true;
   features.needsCifsUtils = true;
-  features.canDisableNetfilterConntrackHelpers = true;
   features.netfilterRPFilter = true;
   features.chromiumos = true;
 

pkgs/os-specific/linux/kernel/linux-grsecurity.nix

@@ -14,6 +14,5 @@ import ./generic.nix (args // rec {
   features.iwlwifi = true;
   features.efiBootStub = true;
   features.needsCifsUtils = true;
-  features.canDisableNetfilterConntrackHelpers = true;
   features.netfilterRPFilter = true;
 } // (args.argsOverride or {}))

pkgs/os-specific/linux/kernel/linux-mptcp.nix

@@ -46,6 +46,5 @@ import ./generic.nix (args // rec {
   features.iwlwifi = true;
   features.efiBootStub = true;
   features.needsCifsUtils = true;
-  features.canDisableNetfilterConntrackHelpers = true;
   features.netfilterRPFilter = true;
 } // (args.argsOverride or {}))

pkgs/os-specific/linux/kernel/linux-rpi.nix

@@ -17,7 +17,6 @@ stdenv.lib.overrideDerivation (import ./generic.nix (args // rec {
 
   features.iwlwifi = true;
   features.needsCifsUtils = true;
-  features.canDisableNetfilterConntrackHelpers = true;
   features.netfilterRPFilter = true;
 
   extraMeta.hydraPlatforms = [];

pkgs/os-specific/linux/kernel/linux-testing.nix

@@ -13,7 +13,6 @@ import ./generic.nix (args // rec {
   features.iwlwifi = true;
   features.efiBootStub = true;
   features.needsCifsUtils = true;
-  features.canDisableNetfilterConntrackHelpers = true;
   features.netfilterRPFilter = true;
 
   # Should the testing kernels ever be built on Hydra?