CVE-2017-15289 Qemu: cirrus: OOB access issue in mode4and5 write functions

[P J P <ppandit () redhat com>]

  Hello,

Quick emulator(Qemu) built with the Cirrus CLGD 54xx VGA Emulator support is 
vulnerable to an out-of-bounds write access issues. It could occur while 
writing to VGA memory via mode4and5 write functions.

A privileged user inside guest could use this flaw to crash the Qemu process 
resulting in DoS.

Upstream patch:
---------------
  -> https://lists.gnu.org/archive/html/qemu-devel/2017-10/msg02557.html

Reference:
----------
  -> https://bugzilla.redhat.com/show_bug.cgi?id=1501290

This issue was reported by Guoxiang Niu.

Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F