(RHSA-2014:0740) 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 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.

• 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)

Red Hat would like to thank Matthew Daley for reporting CVE-2014-1737 and
CVE-2014-1738.

This update also fixes the following bugs:

• A bug in the futex system call could result in an overflow when passing
  a very large positive timeout. As a consequence, the FUTEX_WAIT operation
  did not work as intended and the system call was timing out immediately.
  A backported patch fixes this bug by limiting very large positive timeouts
  to the maximal supported value. (BZ#1091832)

• A new Linux Security Module (LSM) functionality related to the setrlimit
  hooks should produce a warning message when used by a third party module
  that could not cope with it. However, due to a programming error, the
  kernel could print this warning message when a process was setting rlimits
  for a different process, or if rlimits were modified by another than the
  main thread even though there was no incompatible third party module. This
  update fixes the relevant code and ensures that the kernel handles this
  warning message correctly. (BZ#1092869)

• Previously, the kernel was unable to detect KVM on system boot if the
  Hyper-V emulation was enabled. A patch has been applied to ensure that
  both KVM and Hyper-V hypervisors are now correctly detected during system
  boot. (BZ#1094152)

• A function in the RPC code responsible for verifying whether cached
  credentials match the current process did not perform the check correctly.
  The code checked only whether the groups in the current process
  credentials appear in the same order as in the cached credentials but did
  not ensure that no other groups are present in the cached credentials. As
  a consequence, when accessing files in NFS mounts, a process with the same
  UID and GID as the original process but with a non-matching group list
  could have been granted an unauthorized access to a file, or under certain
  circumstances, the process could have been wrongly prevented from
  accessing the file. The incorrect test condition has been fixed and the
  problem can no longer occur. (BZ#1095062)

• When being under heavy load, some Fibre Channel storage devices, such as
  Hitachi and HP Open-V series, can send a logout (LOGO) message to the
  host system. However, due to a bug in the lpfc driver, this could result
  in a loss of active paths to the storage and the paths could not be
  recovered without manual intervention. This update corrects the lpfc
  driver to ensure automatic recovery of the lost paths to the storage in
  this scenario. (BZ#1096061)

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.