(RHSA-2015:0285) Important: kernel security and bug fix update

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

• A flaw was found in the way the Linux kernel’s SCTP implementation
  validated INIT chunks when performing Address Configuration Change
  (ASCONF). A remote attacker could use this flaw to crash the system by
  sending a specially crafted SCTP packet to trigger a NULL pointer
  dereference on the system. (CVE-2014-7841, Important)

This issue was discovered by Liu Wei of Red Hat.

This update also fixes the following bugs:

• Due to several bugs in the network console logging, a race condition
  between the network console send operation and the driver’s IRQ handler
  could occur, or the network console could access invalid memory content.
  As a consequence, the respective driver, such as vmxnet3, triggered a
  BUG_ON() assertion and the system terminated unexpectedly. A patch
  addressing these bugs has been applied so that driver’s IRQs are disabled
  before processing the send operation and the network console now accesses
  the RCU-protected (read-copy update) data properly. Systems using the
  network console logging no longer crashes due to the aforementioned
  conditions. (BZ#1165983)

• A bug in the vmxnet3 driver allowed potential race conditions to be
  triggered when the driver was used with the netconsole module. The race
  conditions allowed the driver’s internal New API (NAPI) poll routine to run
  concurrently with the netpoll controller routine, which resulted in data
  corruption and a subsequent kernel panic. To fix this problem, the vmxnet3
  driver has been modified to call the appropriate interrupt handler to
  schedule NAPI poll requests properly. (BZ#1179594)

• Prior to this update, nfs_mark_return_delegation() was called without any
  locking, resulting in unsafe dereferencing of delegation->inode.
  Because the inode is only used to discover the nfs_client, the callers now
  pass a valid pointer to the nfs_server as a parameter. (BZ#1187637)

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.