CVE-2016-4439 Qemu: scsi: esp: OOB write while writing to 's->cmdbuf' in esp_reg_write

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

  Hello,

Quick Emulator(Qemu) built with the ESP/NCR53C9x controller emulation support 
is vulnerable to an OOB write access issue. The controller uses 16-byte FIFO 
buffer for command and data transfer. The OOB write occurs while writing to 
this command buffer in esp_reg_write().

A privileged user inside guest could use this flaw to crash the Qemu process 
resulting in DoS OR potentially leverage it to execute arbitrary code with 
privileges of the Qemu process on the host.

Upstream patch:
---------------
  -> https://lists.gnu.org/archive/html/qemu-devel/2016-05/msg03273.html

Reference:
----------
  -> https://bugzilla.redhat.com/show_bug.cgi?id=1337502

This issue was discovered by Li Qiang of 360.cn Inc.

'CVE-2016-4439' has been assigned to it by Red Hat Inc.

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