full-disclosure - Re: [FD] [oss-security] CVE-2014-0196: Linux kernel pty layer race condition memory corruption

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Message-ID: <CAD3CanfdH8xjHR0qYaoEHQ7k0VwUqG4nRMNogeM3Yz-SD_yVDQ@mail.gmail.com>
Date: Mon, 12 May 2014 21:23:57 +1200
From: Matthew Daley <mattd@...fuzz.com>
To: oss-security@...ts.openwall.com
Cc: fulldisclosure@...lists.org
Subject: Re: [FD] [oss-security] CVE-2014-0196: Linux kernel pty layer race
 condition memory corruption

Sorry, forgot to mention that this targets 64-bit kernels.

On Mon, May 12, 2014 at 9:15 PM, Matthew Daley <mattd@...fuzz.com> wrote:
> Hi,
>
> I've written a "slightly-less-than-POC" privilege escalation exploit for
> this vulnerability that works on newer kernels:
> http://bugfuzz.com/stuff/cve-2014-0196-md.c (SHA1:
> 6b1c5c651231b33a5e11b5c8c6ed07cd15f658f5)
>
> Note the warning mentioned in the header; run it at your own risk ;)
>
> - Matthew Daley
>
>
> On Mon, May 5, 2014 at 10:08 PM, Marcus Meissner <meissner@...e.de> wrote:
>>
>> Hi,
>>
>> SUSE customer Ericsson reported a kernel crash to us which turned out
>> to be a race condition in the PTY write buffer handling.
>>
>> When two processes/threads write to the same pty, the buffer end could
>> be overwritten and so memory corruption into adjacent buffers could lead
>> to crashes / code execution.
>>
>> Jiri Slaby and Peter Hurley localized and fixed this problem.
>>
>> CVE-2014-0196 has been assigned to this issue.
>>
>> Jiri thinks this was introduced during 2.6.31 development by
>> d945cb9cce20ac7143c2de8d88b187f62db99bdc (pty: Rework the pty
>> layer to use the normal buffering logic) in 2.6.31-rc3. Until then, pty
>> was writing directly to a line discipline without using buffers.
>>
>> https://bugzilla.novell.com/show_bug.cgi?id=875690
>>
>> Patch is also attached.
>>
>> Ciao, Marcus
>
>

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