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Date: Mon, 11 Jul 2016 13:32:18 +0200
From: Cedric Buissart <cbuissar@...hat.com>
To: Hanno Böck <hanno@...eck.de>
Cc: oss-security@...ts.openwall.com
Subject: Re: CVE-2016-5011: util-linux: Extended partition loop
 in MBR partition table leads to DoS

On Mon, Jul 11, 2016 at 12:51 PM, Hanno Böck <hanno@...eck.de> wrote:

> On Mon, 11 Jul 2016 12:11:43 +0200
> Cedric Buissart <cbuissar@...hat.com> wrote:
>
> > CVE-2016-5011: util-linux: Extended partition loop in MBR partition
> > table leads to DoS
>
> Have you discovered this bug or do you know how it was discovered?
>
It was reported to us by Michael Gruhn & Christian Moch

>
> Was it found with fuzzing or code inspection?
>
I do not know, there was no info on the discovery method in the report.

>
> I have done fuzzing on partitioning tools before, however I hadn't
> found anything, this bug indicates I haven't looked enough :-)
>
I looked at other projects to see what is being done to prevent this
particular loop from happening. Until now, tools I checked are protected
either by detecting the loop (i.e.: actively searching for a relative
offset of 0 for the next EBR, as done by this util-linux patch; partprobe
and fdisk are doing that), or enforcing a limit on the maximum number of
partitions for a device (Linux kernel, kpartx & other tools I currently
checked)

>
>
> --
> Hanno Böck
> https://hboeck.de/
>
> mail/jabber: hanno@...eck.de
> GPG: BBB51E42
>



-- 
Cedric Buissart,
Product Security

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