Re: [gentoo-user] Dirty COW, 4.4.8-hardened-r1 how to fix?

[Fernando Rodriguez]

On Tue, Oct 25, 2016 at 07:38:01PM +0200, Miroslav Rovis wrote:
> Sorry about noticing your reply only now.
>
> Namely, thinking that people over at hardened ML would tell more about
> it, I indirectly initiated a thread over at hardened ML:
> https://archives.gentoo.org/gentoo-hardened/message/09bbf3bfe59a938f11ac044e891db77e
>
> Will surely check it! And am CC'ing hardened about this patch at the
> hardened ML. Maybe they patch and forward the 4.4.8-r1 to 4.4.8-r2 .
> ---
> Only now looked at the patch.
>
> No, you don't get it. And I'm not CC'ing this to hardened ML.
>
> You can't just run the patch for a vanilla kernel onto a
> grsecurity-patched kernel. Look up the hardened-sources, and how they
> are patched, and what the mm.h and the gup.c in question (there are a
> few of so named files in various directories) look in the
> hardened-sources, and how they look in the vanilla-sources...

fernan@navi /usr/src/linux-4.4.8-hardened-r1 $ sudo patch -p1 < /home/fernan/dirtycow.patch
patching file include/linux/mm.h
Hunk #1 succeeded at 2131 (offset 19 lines).
patching file mm/gup.c
Hunk #3 succeeded at 357 (offset -5 lines).

It works so I guess you can. Never say you can't do something before
trying cause then you look like an idiot.

And the patch says which are the files in question!

>
> If I'm not mistaken, and I did check it. No, I'm not mistaken, you just
> sent me the Linus's patch.

Yes you are mistaken, cause if you've tried it you wouldb't be asking
the question. And yes, that is Linus patch.

>
> No, wrong. But thanks for trying to help!
>
> On 161025-13:16-0400, Fernando Rodriguez wrote:
> > On Tue, Oct 25, 2016 at 07:11:54AM +0200, Miroslav Rovis wrote:
> > > On 161021-11:04-0400, Rich Freeman wrote:
> > > > On Fri, Oct 21, 2016 at 10:49 AM, Mick <michaelkintzios@×××××.com> wrote:
> > > > > https://github.com/dirtycow/dirtycow.github.io/wiki/VulnerabilityDetails
> > > >
> > > > Not yet:
> > > > https://bugs.gentoo.org/show_bug.cgi?id=597624
> > > >
> > >
> > > We are talking grsecurity-patched (kind of stable[*]) kernel sources,
> > > the =sys-kernel/hardened-sources-4.4.8-r1 package [**].
> > >
> > > I read most of the discussion, and I could easily patch the gup.c and
> > > mm.h in question, but those files need to be patched before application
> > > of the grsecurity patch, and that is a little more complex work.
> >
> > Did you tried it?
> > The patch attached comes straight from the git repo, just run:
> >
> > # cd /usr/src/linux
> > # patch -p1 < path/to/patch
> >
> > It'll likely work.
> >
> > >
> > > Has anybody done this, as I have limited time available to practice user
> > > patching (which in its simplest form, I was able to do here:
> > > >=dev-libs/nss-3.24 - Add USE flag to enable SSL key
> > > https://bugs.gentoo.org/show_bug.cgi?id=587116#c2 ), in case it can be
> > > done with user patching, of course.
> > >
> > > Anyone?
> > >
> > > Regards!
> > > ---
> > > [*] kind of stable, because there are, since about 1 yrs ago, only
> > > testing kernel available for the non-paying users ;-(
> > >
> > > [**] I have to use 4.4.8.r1 because recent kernel all crash with libirt
> > > and qemu which I am trying to use:
> > > https://bugs.gentoo.org/show_bug.cgi?id=597554
> > > --
> > > Miroslav Rovis
> > > Zagreb, Croatia
> > > http://www.CroatiaFidelis.hr
> >
> >
> >
> > --
> > Fernando Rodriguez
>
> > commit 1294d355881cc5c3421d24fee512f16974addb6c
> > Author: Linus Torvalds <torvalds@××××××××××××××××.org>
> > Date:   Thu Oct 13 13:07:36 2016 -0700
> >
> >     mm: remove gup_flags FOLL_WRITE games from __get_user_pages()
> >
> ...
>
> Thanks for trying to help! Regards!
> --
> Miroslav Rovis
> Zagreb, Croatia
> http://www.CroatiaFidelis.hr



-- 
Fernando Rodriguez