CVE request Qemu: net: virtio-net possible remote DoS

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

  Hello,

Qemu emulator built with the Virtual Network Device(virtio-net) support is 
vulnerable to a DoS issue. It could occur while receiving large packets over 
the tuntap/macvtap interfaces and when guest's virtio-net driver did not 
support big/mergeable receive buffers.

An attacker on the local network could use this flaw to disable guest's
networking by sending a large number of jumbo frames to the guest, exhausting
all receive buffers and thus leading to a DoS situation.

Upstream fixes:
---------------
  -> https://lists.gnu.org/archive/html/qemu-devel/2015-09/msg04729.html
  -> https://lists.gnu.org/archive/html/qemu-devel/2015-09/msg04730.html
  -> https://lists.gnu.org/archive/html/qemu-devel/2015-09/msg04731.html

[PATCH 3/3] above fixes this issue by discarding the used descriptors.

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