Important: kernel security and bug fix update

Updated kernel packages that fix multiple security issues and various bugs
are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having
important security impact. Common Vulnerability Scoring System (CVSS) base
scores, which give detailed severity ratings, are available for each
vulnerability from the CVE links in the References section.

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.

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

To install kernel packages manually, use "rpm -ivh [package]". Do not
use "rpm -Uvh" as that will remove the running kernel binaries from
your system. You may use "rpm -e" to remove old kernels after
determining that the new kernel functions properly on your system.

645222 - CVE-2010-3858 kernel: setup_arg_pages: diagnose excessive argument size
698057 - CVE-2011-1598 CVE-2011-1748 kernel: missing check in can/bcm and can/raw socket releases
703011 - CVE-2011-1770 kernel: dccp: handle invalid feature options length
703016 - CVE-2011-1771 kernel: cifs oops when creating file with O_DIRECT set
704014 - [brocade 6.1 bug] bfa fc staying tech preview [rhel-6.1.z]

https://www.redhat.com/security/data/cve/CVE-2010-3858.html
https://www.redhat.com/security/data/cve/CVE-2011-1598.html
https://www.redhat.com/security/data/cve/CVE-2011-1748.html
https://www.redhat.com/security/data/cve/CVE-2011-1770.html
https://www.redhat.com/security/data/cve/CVE-2011-1771.html
https://access.redhat.com/security/updates/classification/#important
https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/6.1_Technical_Notes/kernel.html#RHSA-2011-0836