RHSA-2011:1419 - Security Advisory

Topic

Updated kernel packages that fix two security issues and four bugs are now
available for Red Hat Enterprise Linux 5.6 Extended Update Support.

The Red Hat Security Response Team has rated this update as having moderate
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.

Description

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

This update fixes the following security issues:

• The way IPv4 and IPv6 protocol sequence numbers and fragment IDs were

generated could allow a man-in-the-middle attacker to inject packets and
possibly hijack connections. Protocol sequence numbers and fragment IDs are
now more random. (CVE-2011-3188, Moderate)

• A flaw was found in the Linux kernel's clock implementation on 32-bit,

SMP (symmetric multiprocessing) systems. A local, unprivileged user could
use this flaw to cause a divide error fault, resulting in a denial of
service. (CVE-2011-3209, Moderate)

Red Hat would like to thank Dan Kaminsky for reporting CVE-2011-3188, and
Yasuaki Ishimatsu for reporting CVE-2011-3209.

In addition, this update fixes the following bugs:

• When the Global File System 2 (GFS2) file system is suspended, its delete

work queue is also suspended, along with any pending work on the queue.
Prior to this update, if GFS2's transaction lock was demoted while the
delete work queue was suspended, a deadlock could occur on the file system
because the file system tried to flush the work queue in the lock demotion
code. With this update, the delete work queue is no longer flushed by the
lock demotion code, and a deadlock no longer occurs. Instead, the work
queue is flushed by the unmount operation, so that pending work is properly
completed. (BZ#733678)

• A previously applied patch introduced a regression for third-party file

systems that do not set the FS_HAS_IODONE2 flag, specifically, Oracle
Cluster File System 2 (OCFS2). The patch removed a call to the aio_complete
function, resulting in no completion events being processed, causing
user-space applications to become unresponsive. This update reintroduces
the aio_complete function call, fixing this issue. (BZ#734156)

• Certain devices support multiple operation modes. For example, EMC

CLARiiON disk arrays support ALUA mode and their own vendor specific mode
for failover. In Red Hat Enterprise Linux 5.5, a bug was discovered that
prevented tools such as multipath from being able to select the
device/hardware handler plug-in to use. This resulted in the application
(for example, multipath) not working properly. With this update, the kernel
has been modified to allow applications to select the device/hardware
handler to use, thus resolving this issue. (BZ#739900)

• This update improves the performance of delete/unlink operations in a

GFS2 file system with large files by adding a layer of metadata read-ahead
for indirect blocks. (BZ#743805)

Users should upgrade to these updated packages, which contain backported
patches to resolve these issues. The system must be rebooted for this
update to take effect.

Solution

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.

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 ia64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 i386
• Red Hat Enterprise Linux Server - AUS 5.6 x86_64
• Red Hat Enterprise Linux Server - AUS 5.6 ia64
• Red Hat Enterprise Linux Server - AUS 5.6 i386
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 5.6 s390x
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 5.6 ppc
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 5.6 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 5.6 i386

Fixes

• BZ - 732658 - CVE-2011-3188 kernel: net: improve sequence number generation
• BZ - 732878 - CVE-2011-3209 kernel: panic occurs when clock_gettime() is called
• BZ - 733678 - GFS2: recovery stuck on transaction lock [rhel-5.6.z]
• BZ - 739900 - scsi_dh_emc gives "error attaching hardware handler" for EMC active-active SANs [rhel-5.6.z]

CVEs

• CVE-2011-3188
• CVE-2011-3209

References

• https://access.redhat.com/security/updates/classification/#moderate