Re: [PATCH RFC] gcc-plugins: Handle GCC version mismatch for OOT modules

Kees Cook
2021-01-27T10:24:50Z

On Mon, Jan 25, 2021 at 04:19:53PM -0600, Josh Poimboeuf wrote:
> On Mon, Jan 25, 2021 at 02:03:07PM -0800, Kees Cook wrote:
> > On Mon, Jan 25, 2021 at 02:42:10PM -0600, Josh Poimboeuf wrote:
> > > When a GCC version mismatch is detected, print a warning and disable the
> > > plugin. The only exception is the RANDSTRUCT plugin which needs all
> > > code to see the same struct layouts. In that case print an error.
> >
> > I prefer this patch as-is: only randstruct needs a hard failure. The
> > others likely work (in fact, randstruct likely works too).
>
> I'm curious about this last statement, why would randstruct likely work?
>
> Even struct module has '__randomize_layout', wouldn't basic module init
> go splat?

No; the seed is part of the generate includes -- you'll get the same
layout with the same seed.

--
Kees Cook