Re: [PATCH RFC 3/4] x86/pti: don't mark the user PGD with _PAGE_NX.

[Linus Torvalds]

On Mon, Jan 8, 2018 at 10:25 AM, Alan Cox <gnomes@xxxxxxxxxxxxxxxxxxx> wrote:
>
> I still think cgroups are the best model for this. In particular it
> naturally fits things like containers, or network facing apps that fork
> helpers.
>
> Secondly when you are looking at barrier semantics between client/client
> a cgroup is much more natural as a way to group processes together who
> don't need to be protected from each other as they are trusting each
> other. (Or we could just harcode this based upon ptraceability ?)

I agree that cgroups would be fairly natural, but I do think we could
look at things like simply trusted users too ("running as root? Yeah,
we're not going to try to protect the kernel from you") and/or trusted
binaries.

But all of those things are likely things that can easily be
determined at execve() time.

                      Linus