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Date: Fri, 13 Dec 2013 10:50:32 +1100
From: Ryan Mallon <rmallon@gmail.com>
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To: Kees Cook <keescook@chromium.org>, "Theodore Ts'o" <tytso@mit.edu>,
        vegard.nossum@oracle.com, LKML <linux-kernel@vger.kernel.org>,
        Tommi Rantala <tt.rantala@gmail.com>, Ingo Molnar <mingo@kernel.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Alan Cox <alan@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jason Wang <jasowang@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        James Morris <james.l.morris@oracle.com>
Subject: Re: [PATCH 1/9] Known exploit detection
References: <1386867152-24072-1-git-send-email-vegard.nossum@oracle.com>	<20131212190659.GG13547@thunk.org> <CAGXu5jKmrtgH8tAGuYd9-gh5-EXqAsPy+XoRMc9DNLDngNH2ug@mail.gmail.com>
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On 13/12/13 08:13, Kees Cook wrote:
> On Thu, Dec 12, 2013 at 11:06 AM, Theodore Ts'o <tytso@mit.edu> wrote:
>> On Thu, Dec 12, 2013 at 05:52:24PM +0100, vegard.nossum@oracle.com wrote:
>>> From: Vegard Nossum <vegard.nossum@oracle.com>
>>>
>>> The idea is simple -- since different kernel versions are vulnerable to
>>> different root exploits, hackers most likely try multiple exploits before
>>> they actually succeed.
> 
> I like this idea. It serves a few purposes, not the least of which is
> very clearly marking in code where we've had problems, regardless of
> the fact that it reports badness to the system owner. And I think
> getting any additional notifications about bad behavior is a nice idea
> too.

Though, if an attacker is running through a series of exploits, and one
eventually succeeds then the first thing to do would be to clean traces
of the _exploit() notifications from the syslog. Since running through a
series of exploits is pretty quick, this can probably all be done before
the sysadmin ever notices.

The _exploit() notifications could also be used to spam the syslogs.
Although they are individually ratelimited, if there are enough
_exploit() markers in the kernel then an annoying person can cycle
through them all to generate large amounts of useless syslog.

~Ryan