Re: [PATCH] unix: properly account for FDs passed over unix sockets

From	Willy Tarreau <w@1wt.eu>
Newsgroups	linux.kernel
Subject	Re: [PATCH] unix: properly account for FDs passed over unix sockets
Date	2015-12-31 08:20 +0100
Message-ID	<qLFGF-1nn-1@gated-at.bofh.it> (permalink)
References	(1 earlier) <qL3L3-1P0-13@gated-at.bofh.it> <qL9dM-5lK-15@gated-at.bofh.it> <qLkLU-4kl-11@gated-at.bofh.it> <qLn73-5Wu-7@gated-at.bofh.it> <qLEAW-LM-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Thu, Dec 31, 2015 at 03:08:53PM +0900, Tetsuo Handa wrote:
> Willy Tarreau wrote:
> > On Wed, Dec 30, 2015 at 09:58:42AM +0100, Hannes Frederic Sowa wrote:
> > > The MSG_PEEK code should not be harmful and the patch is good as is. I 
> > > first understood from the published private thread, that it is possible 
> > > for a program to exceed the rlimit of fds. But the DoS is only by 
> > > keeping the fds in flight and not attaching them to any program.
> > 
> > Exactly. The real issue is when these FDs become very expensive such as
> > pipes full of data.
> > 
> 
> As you wrote how to abuse this vulnerability which exists in Linux 2.0
> and later kernel, I quote a short description from private thread.
> 
>   "an unprivileged user consumes all file descriptors so that other
>   unprivileged user cannot work" and "an unprivileged user consumes all
>   kernel memory so that the OOM killer kills almost all processes before
>   the culprit process is killed (CVE-2013-4312)".
> 
> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Mitigates: CVE-2013-4312 (Linux 2.0+)

Well I didn't reveal any secret as it was publicly reported first
in 2010, it's only that Mark sent us the proof of concept exploit
on the security list recently :-)

    https://bugzilla.kernel.org/show_bug.cgi?id=20402

Anyway I'll resend the patch with your reported-by, the CVE and
Hannes' ACK.

Thanks!
Willy

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Thread

[PATCH] unix: properly account for FDs passed over unix sockets Willy Tarreau <w@1wt.eu> - 2015-12-28 15:20 +0100
  Re: [PATCH] unix: properly account for FDs passed over unix sockets Hannes Frederic Sowa <hannes@stressinduktion.org> - 2015-12-29 15:40 +0100
  Re: [PATCH] unix: properly account for FDs passed over unix sockets Hannes Frederic Sowa <hannes@stressinduktion.org> - 2015-12-29 15:50 +0100
    Re: [PATCH] unix: properly account for FDs passed over unix sockets Willy Tarreau <w@1wt.eu> - 2015-12-29 21:40 +0100
      Re: [PATCH] unix: properly account for FDs passed over unix sockets Hannes Frederic Sowa <hannes@stressinduktion.org> - 2015-12-30 10:00 +0100
        Re: [PATCH] unix: properly account for FDs passed over unix sockets Willy Tarreau <w@1wt.eu> - 2015-12-30 12:30 +0100
          Re: [PATCH] unix: properly account for FDs passed over unix sockets One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2015-12-30 14:20 +0100
          Re: [PATCH] unix: properly account for FDs passed over unix sockets Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2015-12-31 07:10 +0100
            Re: [PATCH] unix: properly account for FDs passed over unix sockets Willy Tarreau <w@1wt.eu> - 2015-12-31 08:20 +0100
              Re: [PATCH] unix: properly account for FDs passed over unix sockets One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2015-12-31 11:40 +0100
  Re: [PATCH] unix: properly account for FDs passed over unix sockets David Miller <davem@davemloft.net> - 2016-01-04 22:50 +0100

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