kernel security update

CentOS Errata and Security Advisory CESA-2013:1790

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

• An information leak flaw was found in the way the Xen hypervisor handled
  error conditions when reading guest memory during certain guest-originated
  operations, such as port or memory mapped I/O writes. A privileged user in
  a fully-virtualized guest could use this flaw to leak hypervisor stack
  memory to a guest. (CVE-2013-4355, Moderate)

Red Hat would like to thank the Xen project for reporting this issue.

This update also fixes the following bugs:

• A previous fix to the kernel did not contain a memory barrier in the
  percpu_up_write() function. Consequently, under certain circumstances, a
  race condition could occur leading to memory corruption and a subsequent
  kernel panic. This update introduces a new memory barrier pair, light_mb()
  and heavy_mb(), for per-CPU basis read and write semaphores
  (percpu-rw-semaphores) ensuring that the race condition can no longer
  occur. In addition, the read path performance of “percpu-rw-semaphores” has
  been improved. (BZ#1014715)

• Due to a bug in the tg3 driver, systems that had the Wake-on-LAN (WOL)
  feature enabled on their NICs could not have been woken up from suspension
  or hibernation using WOL. A missing pci_wake_from_d3() function call has
  been added to the tg3 driver, which ensures that WOL functions properly by
  setting the PME_ENABLE bit. (BZ#1014973)

• Due to an incorrect test condition in the mpt2sas driver, the driver was
  unable to catch failures to map a SCSI scatter-gather list. The test
  condition has been corrected so that the mpt2sas driver now handles SCSI
  scatter-gather mapping failures as expected. (BZ#1018458)

• A previous patch to the kernel introduced the “VLAN tag re-insertion”
  workaround to resolve a problem with incorrectly handled VLAN-tagged
  packets with no assigned VLAN group while the be2net driver was in
  promiscuous mode. However, this solution led to packet corruption and a
  subsequent kernel oops if such a processed packed was a GRO packet.
  Therefore, a patch has been applied to restrict VLAN tag re-insertion only
  to non-GRO packets. The be2net driver now processes VLAN-tagged packets
  with no assigned VLAN group correctly in this situation. (BZ#1023348)

All kernel 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/2013-December/082210.html

Affected packages:
kernel
kernel-PAE
kernel-PAE-devel
kernel-debug
kernel-debug-devel
kernel-devel
kernel-doc
kernel-headers
kernel-xen
kernel-xen-devel

Upstream details at:
https://access.redhat.com/errata/RHSA-2013:1790