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

[Matthew Daley <mattd () bugfuzz com>]

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

On Mon, May 12, 2014 at 9:15 PM, Matthew Daley <mattd () bugfuzz 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 () suse 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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