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Date: Mon, 5 May 2014 12:08:11 +0200
From: Marcus Meissner <>
To: OSS Security List <>
Subject: CVE-2014-0196: Linux kernel pty layer race condition memory


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.

Patch is also attached.

Ciao, Marcus

View attachment "n_tty-Fix-n_tty_write-crash-when-echoing-in-raw-mode.patch" of type "text/x-patch" (3382 bytes)

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