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Groups > linux.kernel > #1621461

Re: [PATCH] mm: Add additional consistency check

From Kees Cook <keescook@chromium.org>
Newsgroups linux.kernel
Subject Re: [PATCH] mm: Add additional consistency check
Date 2017-04-11 18:40 +0200
Message-ID <tv6ZI-Y3-1@gated-at.bofh.it> (permalink)
References (9 earlier) <tv4Oe-85I-27@gated-at.bofh.it> <tv4XU-8aE-23@gated-at.bofh.it> <tv6Gm-QX-17@gated-at.bofh.it> <tv6Gm-QX-15@gated-at.bofh.it> <tv6Q3-Us-23@gated-at.bofh.it>
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On Tue, Apr 11, 2017 at 9:23 AM, Christoph Lameter <cl@linux.com> wrote:
> On Tue, 11 Apr 2017, Kees Cook wrote:
>
>> It seems that enabling the debug checks comes with a non-trivial
>> performance impact. I'd like to see consistency checks by default so
>> we can handle intentional heap corruption attacks better. This check
>> isn't expensive...
>
> Its in a very hot code and frequently used code path.

Yeah, absolutely. All the more reason to make sure the kernel can't be
attacked through it. :) As with the automotive industry analogy[1]
from Konstantin, we need to make sure Linux not only run fast and
efficiently, but also fails gracefully by default.

> Note also that these checks can be enabled and disabled at runtime for
> each slab cache.

Correct, but my understanding is that enabling them through the debug
system ends up being much more expensive than this smaller check. The
debug code is fairly comprehensive, but it's not been designed for
efficient attack detection, etc.

-Kees

[1] http://kernsec.org/files/lss2015/giant-bags-of-mostly-water.pdf

-- 
Kees Cook
Pixel Security

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Thread

Re: [PATCH] mm: Add additional consistency check Kees Cook <keescook@chromium.org> - 2017-04-11 07:00 +0200
  Re: [PATCH] mm: Add additional consistency check Michal Hocko <mhocko@kernel.org> - 2017-04-11 15:50 +0200
    Re: [PATCH] mm: Add additional consistency check Kees Cook <keescook@chromium.org> - 2017-04-11 16:20 +0200
      Re: [PATCH] mm: Add additional consistency check Michal Hocko <mhocko@kernel.org> - 2017-04-11 16:30 +0200
        Re: [PATCH] mm: Add additional consistency check Kees Cook <keescook@chromium.org> - 2017-04-11 18:10 +0200
        Re: [PATCH] mm: Add additional consistency check Kees Cook <keescook@chromium.org> - 2017-04-11 18:20 +0200
          Re: [PATCH] mm: Add additional consistency check Christoph Lameter <cl@linux.com> - 2017-04-11 18:30 +0200
          Re: [PATCH] mm: Add additional consistency check Christoph Lameter <cl@linux.com> - 2017-04-11 18:30 +0200
            Re: [PATCH] mm: Add additional consistency check Kees Cook <keescook@chromium.org> - 2017-04-11 18:40 +0200
        Re: [PATCH] mm: Add additional consistency check Christoph Lameter <cl@linux.com> - 2017-04-11 18:20 +0200
          Re: [PATCH] mm: Add additional consistency check Michal Hocko <mhocko@kernel.org> - 2017-04-11 18:50 +0200
            Re: [PATCH] mm: Add additional consistency check Christoph Lameter <cl@linux.com> - 2017-04-11 20:10 +0200
              Re: [PATCH] mm: Add additional consistency check Michal Hocko <mhocko@kernel.org> - 2017-04-11 20:40 +0200
                Re: [PATCH] mm: Add additional consistency check Christoph Lameter <cl@linux.com> - 2017-04-11 20:50 +0200
                Re: [PATCH] mm: Add additional consistency check Michal Hocko <mhocko@kernel.org> - 2017-04-11 21:00 +0200
                Re: [PATCH] mm: Add additional consistency check Christoph Lameter <cl@linux.com> - 2017-04-11 21:00 +0200
                Re: [PATCH] mm: Add additional consistency check Michal Hocko <mhocko@kernel.org> - 2017-04-11 21:40 +0200
                Re: [PATCH] mm: Add additional consistency check Christoph Lameter <cl@linux.com> - 2017-04-17 17:30 +0200
                Re: [PATCH] mm: Add additional consistency check Michal Hocko <mhocko@kernel.org> - 2017-04-18 08:50 +0200
                Re: [PATCH] mm: Add additional consistency check Christoph Lameter <cl@linux.com> - 2017-04-18 15:40 +0200
                Re: [PATCH] mm: Add additional consistency check Christoph Lameter <cl@linux.com> - 2017-04-18 15:40 +0200

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