From a4ac5506f57f767fd53aebd0eeea8db4c911f83f Mon Sep 17 00:00:00 2001
From: c74d <8573dd@gmail.com>
Date: Fri, 24 Mar 2017 01:27:49 +0000
Subject: [PATCH] google-compute-image: fix Yama LSM option conflict

Having fixed the Google Compute Engine image build process's copying
of store paths in PR #24264, I ran `nixos-rebuild --upgrade switch`...
and the GCE image broke again, because it sets the NixOS configuration
option for the sysctl variable `kernel.yama.ptrace_scope` to
`mkDefault "1"`, i.e., with override priority 1000, and now the
`sysctl` module sets the same option to `mkDefault "0"` (this was
changed in commit 86721a5f78718caf10c578e9501f8b4d19c0eb44).

This patch raises the override priority of the Google Compute Engine
image configuration's definition of the Yama sysctl option to 500
(still lower than the priority of an unmodified option definition).

I have tested that this patch allows the Google Compute Engine image
to again build successfully for me.
---
 nixos/modules/virtualisation/google-compute-image.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nixos/modules/virtualisation/google-compute-image.nix b/nixos/modules/virtualisation/google-compute-image.nix
index a03c45bfeff..a3dd3bd55d1 100644
--- a/nixos/modules/virtualisation/google-compute-image.nix
+++ b/nixos/modules/virtualisation/google-compute-image.nix
@@ -261,7 +261,7 @@ in
     "kernel.kptr_restrict" = mkDefault "1";
 
     # set ptrace protections
-    "kernel.yama.ptrace_scope" = mkDefault "1";
+    "kernel.yama.ptrace_scope" = mkOverride 500 "1";
 
     # set perf only available to root
     "kernel.perf_event_paranoid" = mkDefault "2";