Important: kernel security and bug fix update

Updated kernel packages that fix two security issues and three bugs are now
available for Red Hat Enterprise Linux 5.4 Extended Update Support.

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:

* When an application has a stack overflow, the stack could silently
overwrite another memory mapped area instead of a segmentation fault
occurring, which could cause an application to execute arbitrary code,
possibly leading to privilege escalation. It is known that the X Window
System server can be used to trigger this flaw. (CVE-2010-2240, Important)

* A miscalculation of the size of the free space of the initial directory
entry in a directory leaf block was found in the Linux kernel Global File
System 2 (GFS2) implementation. A local, unprivileged user with write
access to a GFS2-mounted file system could perform a rename operation on
that file system to trigger a NULL pointer dereference, possibly resulting
in a denial of service or privilege escalation. (CVE-2010-2798, Important)

Red Hat would like to thank the X.Org security team for reporting
CVE-2010-2240, with upstream acknowledging Rafal Wojtczuk as the original
reporter; and Grant Diffey of CenITex for reporting CVE-2010-2798.

This update also fixes the following bugs:

* Problems receiving network traffic correctly via a non-standard layer 3
protocol when using the ixgbe driver. This update corrects this issue.
(BZ#618275)

* A bug was found in the way the megaraid_sas driver (for SAS based RAID
controllers) handled physical disks and management IOCTLs. All physical
disks were exported to the disk layer, allowing an oops in
megasas_complete_cmd_dpc() when completing the IOCTL command if a timeout
occurred. One possible trigger for this bug was running "mkfs". This update
resolves this issue by updating the megaraid_sas driver to version 4.31.
(BZ#619363)

* Previously, Message Signaled Interrupts (MSI) resulted in PCI bus writes
to mask and unmask the MSI IRQ for a PCI device. These unnecessary PCI bus
writes resulted in the serialization of MSIs, leading to poor performance
on systems with high MSI load. This update adds a new kernel boot
parameter, msi_nolock, which forgoes the PCI bus writes and allows for
better simultaneous processing of MSIs. (BZ#621939)

Users should upgrade to these updated packages, which contain backported
patches to correct these issues. 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
http://kbase.redhat.com/faq/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.

606611 - CVE-2010-2240 kernel: mm: keep a guard page below a grow-down stack segment
618275 - Received data corrupts when non standards L3 protocols are used on ixgbe [rhel-5.4.z]
619363 - [LSI 5.6 feat] update megaraid_sas to version 4.31 [rhel-5.4.z]
620300 - CVE-2010-2798 kernel: gfs2: rename causes kernel panic
621939 - Significant MSI performance issue due to redundant interrupt masking [rhel-5.4.z]

https://www.redhat.com/security/data/cve/CVE-2010-2240.html
https://www.redhat.com/security/data/cve/CVE-2010-2798.html
http://www.redhat.com/security/updates/classification/#important