Updated kernel packages that fix three security issues and several bugs are
now available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having moderate
security impact. Common Vulnerability Scoring System (CVSS) base scores,
which give detailed severity ratings, are available for each vulnerability
from the CVE links in the References section.

The kernel packages contain the Linux kernel, the core of any Linux
operating system.

This update fixes the following security issues:

* It was found that the Xen hypervisor implementation did not perform
range checking on the guest provided values in multiple hypercalls. A
privileged guest user could use this flaw to trigger long loops, leading
to a denial of service (Xen hypervisor hang). (CVE-2012-5515, Moderate)

* It was found that when running a 32-bit binary that uses a large number
of shared libraries, one of the libraries would always be loaded at a
predictable address in memory. An attacker could use this flaw to bypass
the Address Space Layout Randomization (ASLR) security feature.
(CVE-2012-1568, Low)

* A flaw was found in the way the Linux kernel's IPv6 implementation
handled overlapping, fragmented IPv6 packets. A remote attacker could
potentially use this flaw to bypass protection mechanisms (such as a
firewall or intrusion detection system (IDS)) when sending network packets
to a target system. (CVE-2012-4444, Low)

Red Hat would like to thank the Xen project for reporting CVE-2012-5515,
and Antonios Atlasis working with Beyond Security's SecuriTeam Secure
Disclosure program and Loganaden Velvindron of AFRINIC for reporting
CVE-2012-4444.

This update also fixes several bugs. Space precludes documenting all of
these changes in this advisory. Documentation for these changes will be
available shortly from the Red Hat Enterprise Linux 5.9 Technical Notes
document linked to in the References section.

Users should upgrade to these updated packages, which contain backported
patches to correct these issues. The system must be rebooted for this
update to take effect.

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/knowledge/articles/11258

To install kernel packages manually, use "rpm -ivh [package]". Do not
use "rpm -Uvh" as that will remove the running kernel binaries from
your system. You may use "rpm -e" to remove old kernels after
determining that the new kernel functions properly on your system.

804947 - CVE-2012-1568 kernel: execshield: predictable ascii armour base address
874835 - CVE-2012-4444 kernel: net: acceptation of overlapping ipv6 fragments
877397 - CVE-2012-5515 kernel: xen: Several memory hypercall operations allow invalid extent order values

https://www.redhat.com/security/data/cve/CVE-2012-1568.html
https://www.redhat.com/security/data/cve/CVE-2012-4444.html
https://www.redhat.com/security/data/cve/CVE-2012-5515.html
https://access.redhat.com/security/updates/classification/#moderate
https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/5/html/5.9_Technical_Notes/kernel.html#RHSA-2013-0168