kernel security update

CentOS Errata and Security Advisory CESA-2013:0621

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

This update fixes the following security issues:

• A flaw was found in the way file permission checks for the
  “/dev/cpu/[x]/msr” files were performed in restricted root environments
  (for example, when using a capability-based security model). A local user
  with the ability to write to these files could use this flaw to escalate
  their privileges to kernel level, for example, by writing to the
  SYSENTER_EIP_MSR register. (CVE-2013-0268, Important)

• A race condition was found in the way the Linux kernel’s ptrace
  implementation handled PTRACE_SETREGS requests when the debuggee was woken
  due to a SIGKILL signal instead of being stopped. A local, unprivileged
  user could use this flaw to escalate their privileges. (CVE-2013-0871,
  Important)

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.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2013-March/081806.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-2013:0621