CVE-2020-13659 QEMU: exec: address_space_map returns NULL without setting length to zero may lead to DoS

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

  Hello,

A NULL pointer dereference issue was found in the MegaRAID SAS 8708EM2 
emulator of the QEMU. This issue occurs because the address_space_map() API 
while mapping physical memory into host's virtual address space may return 
NULL, without setting the length parameter to zero(0). A guest user/process 
may use this flaw to crash the QEMU process on the host resulting in DoS 
scenario.

Upstream patch:
---------------
  -> https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg07313.html

Reference:
----------
  -> https://bugs.launchpad.net/qemu/+bug/1878259


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