CVE-2017-8112 Qemu: scsi: vmw_pvscsi: infinite loop in pvscsi_log2

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

  Hello,

Quick Emulator(Qemu) built with the VMWARE PVSCSI paravirtual SCSI bus 
emulation support is vulnerable to an infinite loop issue. It could occur 
while initialising SCSI message ring buffer in pvscsi_ring_init_msg().

A privileged user inside guest could use this flaw to consume host cpu cycles 
or crash the Qemu process resulting in DoS.

Upstream patch:
---------------
  -> https://lists.gnu.org/archive/html/qemu-devel/2017-04/msg04578.html

Reference:
----------
  -> https://bugzilla.redhat.com/show_bug.cgi?id=1445621

This issue was independently reported by Li Qiang of Qihoo 360 Gear 
Team and YY Z(CC'd).

'CVE-2017-8112' assigned via -> http://cveform.mitre.org/

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