(RHSA-2014:0108) Moderate: kernel security and bug fix update

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

• It was found that the Xen hypervisor did not always lock
  ‘page_alloc_lock’ and ‘grant_table.lock’ in the same order. This could
  potentially lead to a deadlock. A malicious guest administrator could use
  this flaw to cause a denial of service on the host. (CVE-2013-4494,
  Moderate)

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

This update also fixes the following bugs:

• A recent patch to the CIFS code that introduced the NTLMSSP
  (NT LAN Manager Security Support Provider) authentication mechanism caused
  a regression in CIFS behavior. As a result of the regression, an encryption
  key that is returned during the SMB negotiation protocol response was only
  used for the first session that was created on the SMB client. Any
  subsequent mounts to the same server did not use the encryption key
  returned by the initial negotiation with the server. As a consequence, it
  was impossible to mount multiple SMB shares with different credentials to
  the same server. A patch has been applied to correct this problem so that
  an encryption key or a server challenge is now provided for every SMB
  session during the SMB negotiation protocol response. (BZ#1029865)

• The igb driver previously used a 16-bit mask when writing values of the
  flow control high-water mark to hardware registers on a network device.
  Consequently, the values were truncated on some network devices, disrupting
  the flow control. A patch has been applied to the igb driver so that it now
  uses a 32-bit mask as expected. (BZ#1041694)

• The IPMI driver did not properly handle kernel panic messages.
  Consequently, when a kernel panic occurred on a system that was utilizing
  IPMI without Kdump being set up, a second kernel panic could be triggered.
  A patch has been applied to the IPMI driver to fix this problem, and a
  message handler now properly waits for a response to panic event messages.
  (BZ#1049731)

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.