(RHSA-2014:1959) 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 permission checks performed by the Linux kernel
  when a netlink message was received were not sufficient. A local,
  unprivileged user could potentially bypass these restrictions by passing a
  netlink socket as stdout or stderr to a more privileged process and
  altering the output of this process. (CVE-2014-0181, Moderate)

Red Hat would like to thank Andy Lutomirski for reporting this issue.

This update also fixes the following bugs:

• Previously, the kernel did not successfully deliver multicast packets
  when the multicast querier was disabled. Consequently, the corosync utility
  terminated unexpectedly and the affected storage node did not join its
  intended cluster. With this update, multicast packets are delivered
  properly when the multicast querier is disabled, and corosync handles the
  node as expected. (BZ#902454)

• Previously, the kernel wrote the metadata contained in all system
  information blocks on a single page of the /proc/sysinfo file. However,
  when the machine configuration was very extensive and the data did not fit
  on a single page, the system overwrote random memory regions, which in turn
  caused data corruption when reading the /proc/sysconf file. With this
  update, /proc/sysinfo automatically allocates a larger buffer if the data
  output does not fit the current buffer, which prevents the data corruption.
  (BZ#1131283)

• Prior to this update, the it_real_fn() function did not, in certain
  cases, successfully acquire the SIGLOCK signal when the do_setitimer()
  function used the ITIMER_REAL timer. As a consequence, the current process
  entered an endless loop and became unresponsive. This update fixes the bug
  and it_real_fn() no longer causes the kernel to become unresponsive.
  (BZ#1134654)

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.