(RHSA-2014:0786) Important: kernel security, bug fix, and enhancement 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 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)

• Use-after-free and information leak flaws were found in the way the
  Linux kernel’s floppy driver processed the FDRAWCMD IOCTL command. A local
  user with write access to /dev/fdX could use these flaws to escalate their
  privileges on the system. (CVE-2014-1737, CVE-2014-1738, Important)

• It was found that the aio_read_events_ring() function of the Linux
  kernel’s Asynchronous I/O (AIO) subsystem did not properly sanitize the AIO
  ring head received from user space. A local, unprivileged user could use
  this flaw to disclose random parts of the (physical) memory belonging to
  the kernel and/or other processes. (CVE-2014-0206, Moderate)

• An out-of-bounds memory access flaw was found in the Netlink Attribute
  extension of the Berkeley Packet Filter (BPF) interpreter functionality in
  the Linux kernel’s networking implementation. A local, unprivileged user
  could use this flaw to crash the system or leak kernel memory to user space
  via a specially crafted socket filter. (CVE-2014-3144, CVE-2014-3145,
  Moderate)

• An information leak flaw was found in the way the skb_zerocopy() function
  copied socket buffers (skb) that are backed by user-space buffers (for
  example vhost-net and Xen netback), potentially allowing an attacker to
  read data from those buffers. (CVE-2014-2568, Low)

Red Hat would like to thank Kees Cook of Google for reporting
CVE-2014-3153 and Matthew Daley for reporting CVE-2014-1737 and CVE-2014-1738.
Google acknowledges Pinkie Pie as the original reporter of
CVE-2014-3153. The CVE-2014-0206 issue was discovered by Mateusz Guzik of
Red Hat.

This update also fixes the following bugs:

• Due to incorrect calculation of Tx statistics in the qlcninc driver,
  running the “ethtool -S ethX” command could trigger memory corruption.
  As a consequence, running the sosreport tool, that uses this command,
  resulted in a kernel panic. The problem has been fixed by correcting the
  said statistics calculation. (BZ#1104972)

• When an attempt to create a file on the GFS2 file system failed due to a
  file system quota violation, the relevant VFS inode was not completely
  uninitialized. This could result in a list corruption error. This update
  resolves this problem by correctly uninitializing the VFS inode in this
  situation. (BZ#1097407)

• Due to a race condition in the kernel, the getcwd() system call could
  return “/” instead of the correct full path name when querying a path name
  of a file or directory. Paths returned in the “/proc” file system could
  also be incorrect. This problem was causing instability of various
  applications. The aforementioned race condition has been fixed and getcwd()
  now always returns the correct paths. (BZ#1099048)

In addition, this update adds the following enhancements:

• The kernel mutex code has been improved. The changes include improved
  queuing of the MCS spin locks, the MCS code optimization, introduction of
  the cancellable MCS spin locks, and improved handling of mutexes without
  wait locks. (BZ#1103631, BZ#1103629)

• The handling of the Virtual Memory Area (VMA) cache and huge page faults
  has been improved. (BZ#1103630)

All kernel users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues and add these
enhancements. The system must be rebooted for this update to take effect.