Re: [PATCH v4 0/3] Actually fix freelist pointer vs redzoning

From: Kees Cook
Date: Tue Jun 08 2021 - 19:08:35 EST


On Tue, Jun 08, 2021 at 01:53:27PM -0700, Andrew Morton wrote:
> On Tue, 8 Jun 2021 11:39:52 -0700 Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>
> > This fixes redzoning vs the freelist pointer (both for middle-position
> > and very small caches). Both are "theoretical" fixes, in that I see no
> > evidence of such small-sized caches actually be used in the kernel, but
> > that's no reason to let the bugs continue to exist, especially since
> > people doing local development keep tripping over it. :)
>
> So I don't think this is suitable -stable material?

Yeah, I think it's -stable material, but I'd like some bake time in
-next just in case. zplin saw that there was a 2 * sizeof(void *) case
that existed in the kernel that would trip over the issue.

> It's a bit odd that patches 2&3 were cc:stable but #1 was not. Makes
> one afraid that 2&3 might have had a dependency anyway.

#1 is entirely cosmetic. It should also be fine to put into -stable, but
since it had no operational impact, I figured it didn't need to be.

> So I'm thinking that the whole series can just be for 5.14-rc1, in the
> sent order.

Unless I'm missing something big, yeah, that would be my preference too.
(And -stable can pick it up then.)

--
Kees Cook