Re: [stable] please do not merge 058504edd026 (was Re: fs: use after free in /proc/pid/mountinfo)

From: Greg KH
Date: Mon Jul 07 2014 - 19:15:30 EST


On Mon, Jul 07, 2014 at 04:06:27PM -0700, Andrew Morton wrote:
> On Mon, 7 Jul 2014 16:05:42 -0700 Greg KH <greg@xxxxxxxxx> wrote:
>
> > On Fri, Jul 04, 2014 at 03:35:54PM -0700, David Rientjes wrote:
> > > On Fri, 4 Jul 2014, Sasha Levin wrote:
> > >
> > > > > Does this now reproduce on Linus's tree? If so, does reverting commit
> > > > > 058504edd026 ("fs/seq_file: fallback to vmalloc allocation") prevent this
> > > > > issue?
> > > > >
> > > > > This is a use-after-free since the poison value is 0x6b and I'm presuming
> > > > > that your /proc/self/mountinfo may be larger than PAGE_SIZE in your
> > > > > testing environment.
> > > > >
> > > >
> > > > Good call, reverting that patch made both issues go away.
> > > >
> > >
> > > Thanks for checking, Sasha.
> > >
> > > Stable maintainers, please do not merge commit 058504edd026 ("fs/seq_file:
> > > fallback to vmalloc allocation") that is annotated with a cc for
> > > stable@xxxxxxxxxxxxxxx in Linus's tree into stable kernels.
> > >
> > > Although we're at 3.16-rc3, I'm hoping that we can get a fix for the
> > > use-after-free in the next couple days before asking for a revert. Sasha
> > > confirms[*] this commit causes the bug.
> >
> > I should also drop "Subject: /proc/stat: convert to single_open_size()"
> > from the -stable tree, right?
> >
>
> That would be best.

Ok, now dropped, thanks.

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/