CVE-2017-15119 Qemu: DoS via large option request

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

  Hello,

Quick Emulator(Qemu) built with the Network Block Device(NBD) server support 
is vulnerable to a denial-of-service issue. It could occur if a client sent 
large option requests, making server waste CPU time on reading up to 4G bytes.

A client could use this flaw to keep the NBD server from serving other 
requests, resulting in DoS.

Upstream patch:
---------------
  -> https://lists.gnu.org/archive/html/qemu-devel/2017-11/msg05044.html

Reference:
----------
  -> https://bugzilla.redhat.com/show_bug.cgi?id=1516925

Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
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