xen security update

CentOS Errata and Security Advisory CESA-2011:0496

The xen packages contain administration tools and the xend service for
managing the kernel-xen kernel for virtualization on Red Hat Enterprise
Linux.

It was found that the xc_try_bzip2_decode() and xc_try_lzma_decode() decode
routines did not correctly check for a possible buffer size overflow in the
decoding loop. As well, several integer overflow flaws and missing
error/range checking were found that could lead to an infinite loop. A
privileged guest user could use these flaws to crash the guest or,
possibly, execute arbitrary code in the privileged management domain
(Dom0). (CVE-2011-1583)

All xen users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. The system must be
rebooted for this update to take effect.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2011-May/079700.html
https://lists.centos.org/pipermail/centos-announce/2011-May/079701.html

Affected packages:
xen
xen-devel
xen-libs

Upstream details at:
https://access.redhat.com/errata/RHSA-2011:0496