CVE-2016-0723: Linux kernel: Kernel memory disclosure.

[Wade Mealing <wmealing () redhat com>]

A flaw was discovered in the linux kernel tty subsystem which allows
for disclosure of uncontrolled memory location and possible kernel
panic. The information leak is caused by a race condition when
attempting to set and read the tty line discipline.

An attacker can use the TIOCSETD (via tty_set_ldisc ) to switch to a
new line discipline, a concurrent call to with a TIOCGETD ioctl
performs a read on a given tty may be able to access memory previously
 allocated.  Up to 4 bytes may leaked to userspace when querying the
line discipline.

Thanks,

Wade Mealing
Red Hat Product Security

Upstream fix:
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=5c17c861a357e9458001f021a7afa7aab9937439

Upstream discussion:
http://lkml.iu.edu/hypermail/linux/kernel/1511.3/03045.html

Red Hat bugzilla:
https://bugzilla.redhat.com/show_bug.cgi?id=1296253