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

[Borislav Petkov]

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@xxxxxxxxx> 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.

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