(RHSA-2013:0496) Important: Red Hat Enterprise Linux 6 kernel update

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

This update fixes the following security issues:

• A race condition was found in the way asynchronous I/O and fallocate()
  interacted when using the ext4 file system. A local, unprivileged user
  could use this flaw to expose random data from an extent whose data blocks
  have not yet been written, and thus contain data from a deleted file.
  (CVE-2012-4508, Important)

• A flaw was found in the way the vhost kernel module handled descriptors
  that spanned multiple regions. A privileged guest user in a KVM guest could
  use this flaw to crash the host or, potentially, escalate their privileges
  on the host. (CVE-2013-0311, Important)

• It was found that the default SCSI command filter does not accommodate
  commands that overlap across device classes. A privileged guest user could
  potentially use this flaw to write arbitrary data to a LUN that is
  passed-through as read-only. (CVE-2012-4542, Moderate)

• A flaw was found in the way the xen_failsafe_callback() function in the
  Linux kernel handled the failed iret (interrupt return) instruction
  notification from the Xen hypervisor. An unprivileged user in a 32-bit
  para-virtualized guest could use this flaw to crash the guest.
  (CVE-2013-0190, Moderate)

• A flaw was found in the way pmd_present() interacted with PROT_NONE
  memory ranges when transparent hugepages were in use. A local, unprivileged
  user could use this flaw to crash the system. (CVE-2013-0309, Moderate)

• A flaw was found in the way CIPSO (Common IP Security Option) IP options
  were validated when set from user mode. A local user able to set CIPSO IP
  options on the socket could use this flaw to crash the system.
  (CVE-2013-0310, Moderate)

Red Hat would like to thank Theodore Ts’o for reporting CVE-2012-4508, and
Andrew Cooper of Citrix for reporting CVE-2013-0190. Upstream acknowledges
Dmitry Monakhov as the original reporter of CVE-2012-4508. The
CVE-2012-4542 issue was discovered by Paolo Bonzini of Red Hat.

This update also fixes several hundred bugs and adds enhancements. Refer to
the Red Hat Enterprise Linux 6.4 Release Notes for information on the most
significant of these changes, and the Technical Notes for further
information, both linked to in the References.

All Red Hat Enterprise Linux 6 users are advised to install these updated
packages, which correct these issues, and fix the bugs and add the
enhancements noted in the Red Hat Enterprise Linux 6.4 Release Notes and
Technical Notes. The system must be rebooted for this update to take
effect.