Re: [OPTIONAL/RFC v2 37/39] x86/cet: Add PTRACE interface for CET

Kees Cook
2022-10-04T19:24:37Z

On Tue, Oct 04, 2022 at 11:44:16AM +0300, Mike Rapoport wrote:
> On Mon, Oct 03, 2022 at 04:59:43PM -0700, Kees Cook wrote:
> > On Thu, Sep 29, 2022 at 03:29:34PM -0700, Rick Edgecombe wrote:
> > > From: Yu-cheng Yu <yu-cheng.yu@intel.com>
> > >
> > > Some applications (like GDB and CRIU) would like to tweak CET state via
> >
> > Eee. Does GDB really need this? Can we make this whole thing
> > CONFIG-depend on CRIU?
>
> GDB, at least its Intel fork uses this. I don't see how they can jump
> between frames without an ability to modify shadow stack contents.
>
> Last I looked they used NT_X86_CET to update SSP and ptrace(POKEDATA) to
> write to the shadow stack.

Okay, thanks! I appreciate having specific examples. :)

--
Kees Cook