(RHSA-2014:0771) 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 futex subsystem handled
  the requeuing of certain Priority Inheritance (PI) futexes. A local,
  unprivileged user could use this flaw to escalate their privileges on the
  system. (CVE-2014-3153, Important)

• A flaw was found in the way the Linux kernel’s floppy driver handled user
  space provided data in certain error code paths while processing FDRAWCMD
  IOCTL commands. A local user with write access to /dev/fdX could use this
  flaw to free (using the kfree() function) arbitrary kernel memory.
  (CVE-2014-1737, Important)

• It was found that the Linux kernel’s floppy driver leaked internal kernel
  memory addresses to user space during the processing of the FDRAWCMD IOCTL
  command. A local user with write access to /dev/fdX could use this flaw to
  obtain information about the kernel heap arrangement. (CVE-2014-1738, Low)

Note: A local user with write access to /dev/fdX could use these two flaws
(CVE-2014-1737 in combination with CVE-2014-1738) to escalate their
privileges on the system.

• It was discovered that the proc_ns_follow_link() function did not
  properly return the LAST_BIND value in the last pathname component as is
  expected for procfs symbolic links, which could lead to excessive freeing
  of memory and consequent slab corruption. A local, unprivileged user could
  use this flaw to crash the system. (CVE-2014-0203, Moderate)

• A flaw was found in the way the Linux kernel handled exceptions when
  user-space applications attempted to use the linkage stack. On IBM S/390
  systems, a local, unprivileged user could use this flaw to crash the
  system. (CVE-2014-2039, Moderate)

• An invalid pointer dereference flaw was found in the Marvell 8xxx
  Libertas WLAN (libertas) driver in the Linux kernel. A local user able to
  write to a file that is provided by the libertas driver and located on the
  debug file system (debugfs) could use this flaw to crash the system. Note:
  The debugfs file system must be mounted locally to exploit this issue.
  It is not mounted by default. (CVE-2013-6378, Low)

• A denial of service flaw was discovered in the way the Linux kernel’s
  SELinux implementation handled files with an empty SELinux security
  context. A local user who has the CAP_MAC_ADMIN capability could use this
  flaw to crash the system. (CVE-2014-1874, Low)

Red Hat would like to thank Kees Cook of Google for reporting
CVE-2014-3153, Matthew Daley for reporting CVE-2014-1737 and CVE-2014-1738,
and Vladimir Davydov of Parallels for reporting CVE-2014-0203. Google
acknowledges Pinkie Pie as the original reporter of CVE-2014-3153.

This update also fixes several bugs. Documentation for these changes will
be available shortly from the Technical Notes document linked to in the
References section.

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.