Re: [kernel-hardening] Re: [PATCH] video: constify geode ops structures

Julia Lawall
2015-11-09T21:55:39Z

On Mon, 9 Nov 2015, Kees Cook wrote:

> On Mon, Nov 9, 2015 at 9:48 AM, Julia Lawall <julia.lawall@lip6.fr> wrote:
> > On Mon, 9 Nov 2015, Emese Revfy wrote:
> >
> >> On Mon, 9 Nov 2015 14:50:47 +0000 (GMT)
> >> Julia Lawall <julia.lawall@lip6.fr> wrote:
> >> > > Actually, it looks like Emese Revfy is going to merge the GCC plugin
> >> > > constify stuff sooner rather than later so maybe adding all these consts
> >> > > isn't going to be needed.
> >> >
> >> > Is there any advantage of const over the plugin? The consts are easy to
> >> > add.
> >>
> >> Hi,
> >>
> >> I think it's a very good advantage that the plugin constifies automatically
> >> without regular maintenance (e.g., generate patches with coccinelle,
> >> send patches to the maintainers every new kernel version). ;)
> >> But if it doesn't convince you, I did constification by hand (with a coccinelle
> >> script) some years ago.
> >> There are too many types that can be const and it took too long to prepare and
> >> get the maintainers to accept the patches.
> >> And it never ends as there are always new types that can be const.
> >
> > What happens if some structures cannot be made const because there is a
> > reassignment somewhere? Is there any feedback about the problem?
>
> AIUI, for now, we can't make those const (though I would be happy to
> be corrected). My hope would be to allow reassignment using something
> like PaX's kernel_open/kernel_close inlines to allow for temporary
> modification of read-only things (as part of the KERNEXEC feature).

What I was more wondering was whether there is any feedback about the
situation?

julia