taskstats: duplicate entries in listener mode can lead to DoS
CVE: CVE-2011-2484
Component: kernel
Severity: Moderate
Release date: 2011-06-16T00:00:00+00:00

The add_del_listener function in kernel/taskstats.c in the Linux kernel 2.6.39.1 and earlier does not prevent multiple registrations of exit handlers, which allows local users to cause a denial of service (memory and CPU consumption), and bypass the OOM Killer, via a crafted application.

Statement: This issue did not affect the versions of Linux kernel as shipped with Red Hat
Enterprise Linux 4 as it did not provide support for the Taskstats interface. This was fixed in Red Hat Enterprise Linux 5, 6, and Red Hat Enterprise MRG via https://rhn.redhat.com/errata/RHSA-2011-1386.html, https://rhn.redhat.com/errata/RHSA-2011-1350.html and https://rhn.redhat.com/errata/RHSA-2011-1253.html.

Remediation:
This update also fixes several bugs and adds one enhancement.
Documentation for these changes 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 correct these issues, and fix the bugs and add
the enhancement 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.
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.
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 correct 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.