CVE-2017-9375 Qemu: usb: xhci infinite recursive call via xhci_kick_ep

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

  Hello,

Quick emulator(Qemu) built with the USB xHCI controller emulator support is 
vulnerable to an infinite recursive call loop issue. It could occur while 
processing control transfer descriptors' sequence in xhci_kick_epctx.

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

Upstream patch:
---------------
  -> http://git.qemu.org/?p=qemu.git;a=commitdiff;h=96d87bdda3919bb16f754b3d3fd1227e1f38f13c

Reference:
----------
  -> https://bugzilla.redhat.com/show_bug.cgi?id=1458744

This issue was reported by Li Qiang Qihoo 360 Gear Team.

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