(RHSA-2014:1101) Important: kernel security and bug fix update

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

• A use-after-free flaw was found in the way the ping_init_sock() function
  of the Linux kernel handled the group_info reference counter. A local,
  unprivileged user could use this flaw to crash the system or, potentially,
  escalate their privileges on the system. (CVE-2014-2851, Important)

• A NULL pointer dereference flaw was found in the rds_ib_laddr_check()
  function in the Linux kernel’s implementation of Reliable Datagram Sockets
  (RDS). A local, unprivileged user could use this flaw to crash the system.
  (CVE-2013-7339, Moderate)

• It was found that a remote attacker could use a race condition flaw in
  the ath_tx_aggr_sleep() function to crash the system by creating large
  network traffic on the system’s Atheros 9k wireless network adapter.
  (CVE-2014-2672, Moderate)

• A NULL pointer dereference flaw was found in the rds_iw_laddr_check()
  function in the Linux kernel’s implementation of Reliable Datagram Sockets
  (RDS). A local, unprivileged user could use this flaw to crash the system.
  (CVE-2014-2678, Moderate)

• A race condition flaw was found in the way the Linux kernel’s mac80211
  subsystem implementation handled synchronization between TX and STA wake-up
  code paths. A remote attacker could use this flaw to crash the system.
  (CVE-2014-2706, Moderate)

This update also fixes the following bugs:

• The Completely Fair Scheduler (CFS) did not verify whether the CFS
  period timer is running while throttling tasks on the CFS run queue.
  Therefore under certain circumstances, the CFS run queue became stuck
  because the CFS period timer was inactive and could not be restarted. To
  fix this problem, the CFS now restarts the CFS period timer inside the
  throttling function if it is inactive. (BZ#1120666)

• A previous change to the SCSI code fixed a race condition that could
  occur when removing a SCSI device. However, that change caused performance
  degradation because it used a certain function from the block layer code
  that was returning different values compared with later versions of the
  kernel. This update alters the SCSI code to properly utilize the values
  returned by the block layer code. (BZ#1117581)

• If a statically defined gateway became unreachable and its corresponding
  neighbor entry entered a FAILED state, the gateway stayed in the FAILED
  state even after it became reachable again. This prevented routing of the
  traffic through that gateway. This update allows probing such a gateway
  automatically and routing the traffic through the gateway again once it
  becomes reachable. (BZ#1115262)

• A miscalculation in the “radix_tree” swap encoding corrupted swap area
  indexes bigger than 8 by truncating lower bits of swap entries.
  Consequently, systems with more than 8 swap areas could trigger a bogus
  OOM scenario when swapping out to such a swap area. This update fixes this
  problem by reducing a return value of the SWP_TYPE_SHIFT() function and
  removing a broken function call from the read_swap_header() function.
  (BZ#1099727)

• The automatic route cache rebuilding feature could incorrectly compute
  the length of a route hash chain if the cache contained multiple entries
  with the same key but a different TOS, mark, or OIF bit. Consequently, the
  feature could reach the rebuild limit and disable the routing cache on the
  system. This problem is fixed by using a helper function that avoids
  counting such duplicate routes. (BZ#1113823)

• When booting a guest in the Hyper-V environment and enough of
  Programmable Interval Timer (PIT) interrupts were lost or not injected
  into the guest on time, the kernel panicked and the guest failed to boot.
  This problem has been fixed by bypassing the relevant PIT check when the
  guest is running under the Hyper-V environment. (BZ#1112225)

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.