CVE request Qemu: ide: ahci null pointer dereference when using FIS CLB engines

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

  Hello,

Qemu emulator built with an IDE AHCI emulation support is vulnerable to a null 
pointer dereference flaw. It occurs while unmapping the Frame Information 
Structure(FIS) & Command List Block(CLB) entries.

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

Upstream patch:
---------------
  -> https://lists.gnu.org/archive/html/qemu-devel/2016-01/msg05742.html

Reference:
----------
  -> https://bugzilla.redhat.com/show_bug.cgi?id=1302057

This issue was discovered by Mr Zuozhi Fzz of Alibaba Inc.


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