(RHSA-2011:0836) Important: kernel security and bug fix update

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

This update fixes the following security issues:

• An integer underflow flaw, leading to a buffer overflow, was found in the
  Linux kernel’s Datagram Congestion Control Protocol (DCCP) implementation.
  This could allow a remote attacker to cause a denial of service.
  (CVE-2011-1770, Important)

• Missing sanity checks were found in setup_arg_pages() in the Linux
  kernel. When making the size of the argument and environment area on the
  stack very large, it could trigger a BUG_ON(), resulting in a local denial
  of service. (CVE-2010-3858, Moderate)

• A missing validation check was found in the bcm_release() and
  raw_release() functions in the Linux kernel’s Controller Area Network (CAN)
  implementation. This could allow a local, unprivileged user to cause a
  denial of service. (CVE-2011-1598, CVE-2011-1748, Moderate)

• The fix for Red Hat Bugzilla bug 656461, as provided in RHSA-2011:0542,
  introduced a regression in the cifs_close() function in the Linux kernel’s
  Common Internet File System (CIFS) implementation. A local, unprivileged
  user with write access to a CIFS file system could use this flaw to cause a
  denial of service. (CVE-2011-1771, Moderate)

Red Hat would like to thank Dan Rosenberg for reporting CVE-2011-1770; Brad
Spengler for reporting CVE-2010-3858; and Oliver Hartkopp for reporting
CVE-2011-1748.

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

Users should upgrade to these updated packages, which contain backported
patches to resolve these issues, and fix the bugs noted in the Technical
Notes. The system must be rebooted for this update to take effect.