From: Willy Tarreau <w@1wt.eu>
To: Michal Hocko <mhocko@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Ben Hutchings <ben@decadent.org.uk>,
Hugh Dickins <hughd@google.com>, Oleg Nesterov <oleg@redhat.com>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Rik van Riel <riel@redhat.com>,
Larry Woodman <lwoodman@redhat.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Tony Luck <tony.luck@intel.com>,
"James E.J. Bottomley" <jejb@parisc-linux.org>,
Helge Diller <deller@gmx.de>,
James Hogan <james.hogan@imgtec.com>,
Laura Abbott <labbott@redhat.com>, Greg KH <greg@kroah.com>,
"security@kernel.org" <security@kernel.org>,
linux-distros@vs.openwall.org,
Qualys Security Advisory <qsa@qualys.com>,
LKML <linux-kernel@vger.kernel.org>,
Ximin Luo <infinity0@debian.org>
Subject: Re: [PATCH] mm: larger stack guard gap, between vmas
Date: Wed, 5 Jul 2017 10:14:43 +0200 [thread overview]
Message-ID: <20170705081443.GA23453@1wt.eu> (raw)
In-Reply-To: <20170705063645.GA10354@dhcp22.suse.cz>
On Wed, Jul 05, 2017 at 08:36:46AM +0200, Michal Hocko wrote:
> PROT_NONE would explicitly fault but we would simply
> run over this mapping too easily and who knows what might end up below
> it. So to me the guard gap does its job here.
I tend to think that applications that implement their own stack guard
using PROT_NONE also assume that they will never perfom unchecked stack
allocations larger than their own guard, thus the condition above should
never happen. Otherwise they're bogus and/or vulnerable by design and it
is their responsibility to fix it.
Thus maybe if that helps we could even relax some of the stack guard
checks as soon as we meet a PROT_NONE area, allowing VMAs to be tightly
packed if the application knows what it's doing. That wouldn't solve
the libreoffice issue though, given the lower page is RWX.
Willy
next prev parent reply other threads:[~2017-07-05 8:15 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <alpine.LSU.2.11.1706190355140.2626@eggly.anvils>
2017-06-22 12:30 ` [PATCH] mm: larger stack guard gap, between vmas Ben Hutchings
2017-06-22 12:46 ` Willy Tarreau
2017-06-22 12:58 ` Ben Hutchings
2017-06-22 13:10 ` Willy Tarreau
2017-06-22 13:28 ` Willy Tarreau
2017-06-22 13:15 ` [vs-plain] " Levente Polyak
2017-06-22 13:59 ` Willy Tarreau
2017-06-22 14:14 ` Ben Hutchings
2017-06-22 14:34 ` Willy Tarreau
2017-06-23 3:10 ` Andy Lutomirski
2017-06-23 4:42 ` Linus Torvalds
2017-06-22 21:23 ` Helge Deller
2017-06-23 4:35 ` Hugh Dickins
2017-06-24 9:11 ` Hugh Dickins
2017-06-24 18:29 ` Ben Hutchings
[not found] ` <CA+55aFx6j4na3BVRC2aQuf-kNp1jzGahN8To_SFpNu+H=gopJA@mail.gmail.com>
[not found] ` <20170619142358.GA32654@1wt.eu>
[not found] ` <1498009101.2655.6.camel@decadent.org.uk>
[not found] ` <20170621092419.GA22051@dhcp22.suse.cz>
[not found] ` <1498042057.2655.8.camel@decadent.org.uk>
2017-07-03 23:55 ` Ben Hutchings
2017-07-04 0:05 ` Linus Torvalds
2017-07-04 8:41 ` Michal Hocko
2017-07-04 9:35 ` Michal Hocko
2017-07-04 9:47 ` Willy Tarreau
2017-07-04 10:42 ` Michal Hocko
2017-07-04 11:36 ` Ben Hutchings
2017-07-04 12:00 ` Michal Hocko
2017-07-04 12:11 ` Michal Hocko
2017-07-04 12:21 ` Ben Hutchings
2017-07-04 12:33 ` Michal Hocko
2017-07-04 14:19 ` Ximin Luo
2017-07-04 14:48 ` Michal Hocko
2017-07-04 15:51 ` Willy Tarreau
2017-07-04 17:22 ` Michal Hocko
2017-07-04 18:37 ` Linus Torvalds
2017-07-04 18:39 ` Willy Tarreau
2017-07-04 18:47 ` Linus Torvalds
2017-07-04 19:03 ` Willy Tarreau
2017-07-04 16:18 ` Linus Torvalds
2017-07-04 16:27 ` John Haxby
2017-07-04 17:02 ` Willy Tarreau
2017-07-05 12:26 ` Ben Hutchings
2017-07-04 17:11 ` Willy Tarreau
2017-07-05 12:25 ` Ben Hutchings
2017-07-04 23:01 ` Ben Hutchings
2017-07-04 23:31 ` Linus Torvalds
2017-07-05 6:36 ` Michal Hocko
2017-07-05 8:14 ` Willy Tarreau [this message]
2017-07-05 8:24 ` Michal Hocko
2017-07-05 9:15 ` Willy Tarreau
2017-07-05 12:21 ` Ben Hutchings
2017-07-05 13:52 ` Willy Tarreau
2017-07-05 14:19 ` Michal Hocko
2017-07-05 16:06 ` Linus Torvalds
2017-07-06 7:34 ` Michal Hocko
2017-07-05 12:19 ` Ben Hutchings
2017-07-05 14:23 ` Michal Hocko
2017-07-05 15:25 ` Ben Hutchings
2017-07-05 15:59 ` Michal Hocko
2017-07-05 16:58 ` Ben Hutchings
2017-07-05 17:05 ` Michal Hocko
2017-07-05 17:24 ` Ben Hutchings
2017-07-05 17:15 ` Linus Torvalds
2017-07-05 23:35 ` Ben Hutchings
2017-07-05 23:51 ` Linus Torvalds
2017-07-06 8:24 ` Willy Tarreau
2017-07-06 10:11 ` Willy Tarreau
2017-07-10 2:40 ` [lkp-robot] [mm] a99d848d3b: kernel_BUG_at_mm/mmap.c kernel test robot
2017-07-05 16:15 ` [PATCH] mm: larger stack guard gap, between vmas Andy Lutomirski
2017-07-05 16:20 ` Linus Torvalds
2017-07-05 17:23 ` Andy Lutomirski
2017-07-05 19:32 ` Ben Hutchings
2017-07-05 20:40 ` Willy Tarreau
2017-07-05 20:53 ` Andy Lutomirski
2017-07-05 23:50 ` Ben Hutchings
2017-07-06 0:23 ` Andy Lutomirski
2017-07-05 23:50 ` Kees Cook
2017-07-05 23:55 ` Linus Torvalds
2017-07-06 0:31 ` Andy Lutomirski
2017-07-06 0:47 ` Linus Torvalds
2017-07-06 0:19 ` Andy Lutomirski
2017-07-06 2:45 ` Kees Cook
2017-07-06 5:23 ` Willy Tarreau
2017-07-06 5:33 ` Kevin Easton
2017-07-05 16:17 ` Linus Torvalds
2017-07-05 18:59 ` Willy Tarreau
2017-07-05 19:17 ` Linus Torvalds
2017-07-05 19:18 ` Willy Tarreau
2017-07-05 19:21 ` Linus Torvalds
2017-07-05 1:16 ` [vs-plain] " kseifried
2017-07-05 14:11 ` Solar Designer
2017-07-04 10:46 ` Michal Hocko
2017-07-04 10:51 ` Michal Hocko
2017-07-04 0:27 ` Andy Lutomirski
2017-07-04 12:26 ` [vs-plain] " John Haxby
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