RHSA-2012:1589 - Security Advisory

Topic

Updated kernel packages that fix one security issue and one bug are now
available for Red Hat Enterprise Linux 6.1 Extended Update Support.

The Red Hat Security Response Team has rated this update as having low
security impact. A Common Vulnerability Scoring System (CVSS) base score,
which gives a detailed severity rating, is available from the CVE link 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 issue:

• A flaw was found in the way the Linux kernel's dl2k driver, used by

certain D-Link Gigabit Ethernet adapters, restricted IOCTLs. A local,
unprivileged user could use this flaw to issue potentially harmful IOCTLs,
which could cause Ethernet adapters using the dl2k driver to malfunction
(for example, losing network connectivity). (CVE-2012-2313, Low)

Red Hat would like to thank Stephan Mueller for reporting this issue.

This update also fixes the following bug:

• The kernel allows high priority real time tasks, such as tasks scheduled

with the SCHED_FIFO policy, to be throttled. Previously, the CPU stop tasks
were scheduled as high priority real time tasks and could be thus throttled
accordingly. However, the replenishment timer, which is responsible for
clearing a throttle flag on tasks, could be pending on the just disabled
CPU. This could lead to the situation that the throttled tasks were never
scheduled to run. Consequently, if any of such tasks was needed to complete
the CPU disabling, the system became unresponsive. This update introduces a
new scheduler class, which gives a task the highest possible system
priority and such a task cannot be throttled. The stop-task scheduling
class is now used for the CPU stop tasks, and the system shutdown completes
as expected in the scenario described. (BZ#876077)

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.

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/knowledge/articles/11258

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 6.1 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.1 i386
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.1 s390x
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.1 ppc64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 i386
• Red Hat Virtual Storage Appliance (from RHUI) 6.1 x86_64

Fixes

• BZ - 818820 - CVE-2012-2313 kernel: unfiltered netdev rio_ioctl access by users

CVEs

• CVE-2012-2313

References

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