Re: [PATCH v21 06/26] x86/cet: Add control-protection fault handler

Borislav Petkov
2021-02-24T19:42:49Z

On Wed, Feb 24, 2021 at 11:30:34AM -0800, Andy Lutomirski wrote:
> On Wed, Feb 24, 2021 at 11:20 AM Borislav Petkov <bp@alien8.de> wrote:
> >
> > On Wed, Feb 24, 2021 at 09:56:13AM -0800, Yu, Yu-cheng wrote:
> > > No. Maybe I am doing too much. The GP fault sets si_addr to zero, for
> > > example. So maybe do the same here?
> >
> > No, you're looking at this from the wrong angle. This is going to be
> > user-visible and the moment it gets upstream, it is cast in stone.
> >
> > So the whole use case of what luserspace needs to do or is going to do
> > or wants to do on a SEGV_CPERR, needs to be described, agreed upon by
> > people etc before it goes out. And thus clarified whether the address
> > gets copied out or not.
>
> I vote 0. The address is in ucontext->gregs[REG_RIP] [0] regardless.
> Why do we need to stick a copy somewhere else?
>
> [0] or however it's spelled. i can never remember.

Fine with me. Let's have this documented in the manpage and then we can
move forward with this.

Thx.

--
Regards/Gruss,
Boris.