RHSA-2012:0480 - Security Advisory

Topic

Updated kernel packages that fix one security issue, various bugs, and add
one enhancement are now available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having
important 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 in the xfrm6_tunnel_rcv() function in the Linux kernel's IPv6

implementation could lead to a use-after-free or double free flaw in
tunnel6_rcv(). A remote attacker could use this flaw to send
specially-crafted packets to a target system that is using IPv6 and also
has the xfrm6_tunnel kernel module loaded, causing it to crash.
(CVE-2012-1583, Important)

If you do not run applications that use xfrm6_tunnel, you can prevent the
xfrm6_tunnel module from being loaded by creating (as the root user) a
"/etc/modprobe.d/xfrm6_tunnel.conf" file, and adding the following line to
it:

blacklist xfrm6_tunnel

This way, the xfrm6_tunnel module cannot be loaded accidentally. A reboot
is not necessary for this change to take effect.

This update also fixes various bugs and adds an 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 this issue, and fix the 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 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 752304 - CVE-2012-1583 kernel: ipv6: panic using raw sockets
• BZ - 801726 - RHEL5.8 NFSv4 regression - "ls" returns "-ENOTDIR" when listing a subdirectory of exported mount [rhel-5.8.z]

CVEs

• CVE-2012-1583

References

• https://access.redhat.com/security/updates/classification/#important
• https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/5.8_Technical_Notes/kernel.html#RHSA-2012-0480