Re: [PATCH v2 29/39] x86/cet/shstk: Support wrss for userspace

Mike Rapoport
2022-10-04T08:31:32Z

On Mon, Oct 03, 2022 at 03:28:47PM -0700, Kees Cook wrote:
> On Thu, Sep 29, 2022 at 03:29:26PM -0700, Rick Edgecombe wrote:
> > For the current shadow stack implementation, shadow stacks contents easily
> > be arbitrarily provisioned with data.
>
> I can't parse this sentence.
>
> > This property helps apps protect
> > themselves better, but also restricts any potential apps that may want to
> > do exotic things at the expense of a little security.
>
> Is anything using this right now? Wouldn't thing be safer without WRSS?
> (Why can't we skip this patch?)

CRIU uses WRSS to restore the shadow stack contents.

> --
> Kees Cook

--
Sincerely yours,
Mike.