(RHSA-2011:0779) Moderate: avahi security and bug fix update

Avahi is an implementation of the DNS Service Discovery and Multicast DNS
specifications for Zero Configuration Networking. It facilitates service
discovery on a local network. Avahi and Avahi-aware applications allow you
to plug your computer into a network and, with no configuration, view other
people to chat with, view printers to print to, and find shared files on
other computers.

A flaw was found in the way the Avahi daemon (avahi-daemon) processed
Multicast DNS (mDNS) packets with an empty payload. An attacker on the
local network could use this flaw to cause avahi-daemon on a target system
to enter an infinite loop via an empty mDNS UDP packet. (CVE-2011-1002)

This update also fixes the following bug:

• Previously, the avahi packages in Red Hat Enterprise Linux 6 were not
  compiled with standard RPM CFLAGS; therefore, the Stack Protector and
  Fortify Source protections were not enabled, and the debuginfo packages did
  not contain the information required for debugging. This update corrects
  this issue by using proper CFLAGS when compiling the packages. (BZ#629954,
  BZ#684276)

All users are advised to upgrade to these updated packages, which contain a
backported patch to correct these issues. After installing the update,
avahi-daemon will be restarted automatically.