RHSA-2012:1580 - Security Advisory

Topic

Updated kernel packages that fix multiple security issues, numerous bugs
and add one enhancement are now available for Red Hat Enterprise Linux 6.

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:

• It was found that the RHSA-2012:0862 update did not correctly fix the

CVE-2011-4131 issue. A malicious Network File System version 4 (NFSv4)
server could return a crafted reply to a GETACL request, causing a denial
of service on the client. (CVE-2012-2375, Moderate)

• A divide-by-zero flaw was found in the TCP Illinois congestion control

algorithm implementation in the Linux kernel. If the TCP Illinois
congestion control algorithm were in use (the sysctl
net.ipv4.tcp_congestion_control variable set to "illinois"), a local,
unprivileged user could trigger this flaw and cause a denial of service.
(CVE-2012-4565, Moderate)

• A NULL pointer dereference flaw was found in the way a new node's hot

added memory was propagated to other nodes' zonelists. By utilizing this
newly added memory from one of the remaining nodes, a local, unprivileged
user could use this flaw to cause a denial of service. (CVE-2012-5517,
Moderate)

• It was found that the initial release of Red Hat Enterprise Linux 6 did

not correctly fix the CVE-2009-4307 issue, a divide-by-zero flaw in the
ext4 file system code. A local, unprivileged user with the ability to mount
an ext4 file system could use this flaw to cause a denial of service.
(CVE-2012-2100, Low)

• A flaw was found in the way the Linux kernel's IPv6 implementation

handled overlapping, fragmented IPv6 packets. A remote attacker could
potentially use this flaw to bypass protection mechanisms (such as a
firewall or intrusion detection system (IDS)) when sending network packets
to a target system. (CVE-2012-4444, Low)

Red Hat would like to thank Antonios Atlasis working with Beyond Security's
SecuriTeam Secure Disclosure program and Loganaden Velvindron of AFRINIC
for reporting CVE-2012-4444. The CVE-2012-2375 issue was discovered by Jian
Li of Red Hat, and CVE-2012-4565 was discovered by Rodrigo Freire of Red
Hat.

This update also fixes numerous bugs and adds one enhancement. Space
precludes documenting all of these changes in this advisory. Documentation
for these changes will be available shortly from the Red Hat Enterprise
Linux 6.3 Technical Notes document linked to in the References section.

Users should upgrade to these updated packages, which contain backported
patches to correct these issues, fix these bugs and add the enhancement
noted in the Technical Notes. 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 Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.3 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.3 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.3 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.3 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.3 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.3 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 809687 - CVE-2012-2100 kernel: ext4: fix inconsistency in ext4_fill_flex_info()
• BZ - 822869 - CVE-2012-2375 kernel: incomplete fix for CVE-2011-4131
• BZ - 871848 - CVE-2012-4565 kernel: net: divide by zero in tcp algorithm illinois
• BZ - 874835 - CVE-2012-4444 kernel: net: acceptation of overlapping ipv6 fragments
• BZ - 875374 - CVE-2012-5517 kernel: mm/hotplug: failure in propagating hot-added memory to other nodes
• BZ - 876549 - drm cherry-pick patch from upstream bug for 6.4 [rhel-6.3.z]

CVEs

• CVE-2012-2100
• CVE-2012-4565
• CVE-2012-5517
• CVE-2012-4444
• CVE-2012-2375

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/html/6.3_Technical_Notes/kernel.html#RHSA-2012-1580
• https://rhn.redhat.com/errata/RHSA-2012-0862.html