CVE-2014-0196: Linux kernel pty layer race condition memory corruption

[Marcus Meissner <meissner () suse de>]

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

Attachment: n_tty-Fix-n_tty_write-crash-when-echoing-in-raw-mode.patch
Description: