Synopsis

Important: kernel security, bug fix, and enhancement update

Type/Severity

Security Advisory: Important

Topic

Updated kernel packages that fix multiple security issues, several bugs,
and add two enhancements are now available for Red Hat Enterprise Linux 6.

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

• A flaw was found in the way the Linux kernel's TCP/IP protocol suite

implementation handled sending of certain UDP packets over sockets that
used the UDP_CORK option when the UDP Fragmentation Offload (UFO) feature
was enabled on the output device. A local, unprivileged user could use this
flaw to cause a denial of service or, potentially, escalate their
privileges on the system. (CVE-2013-4470, Important)

• A divide-by-zero flaw was found in the apic_get_tmcct() function in KVM's

Local Advanced Programmable Interrupt Controller (LAPIC) implementation.
A privileged guest user could use this flaw to crash the host.
(CVE-2013-6367, Important)

• A memory corruption flaw was discovered in the way KVM handled virtual

APIC accesses that crossed a page boundary. A local, unprivileged user
could use this flaw to crash the system or, potentially, escalate their
privileges on the system. (CVE-2013-6368, Important)

• An information leak flaw in the Linux kernel could allow a local,

unprivileged user to leak kernel memory to user space. (CVE-2013-2141, Low)

Red Hat would like to thank Hannes Frederic Sowa for reporting
CVE-2013-4470, and Andrew Honig of Google for reporting CVE-2013-6367 and
CVE-2013-6368.

This update also fixes several bugs and adds two enhancements.
Documentation for these changes will be available shortly from the
Technical Notes document linked to in the References section

All kernel users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues and add these
enhancements. 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/site/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 6.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.5 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• 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 6.5 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.5 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Resilient Storage for x86_64 - Extended Update Support 6.5 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 Update Support from RHUI 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.5 i386
• Red Hat Enterprise Linux EUS Compute Node 6.5 x86_64
• Red Hat Enterprise Linux Server - AUS 6.5 x86_64
• Red Hat Enterprise Linux Server - TUS 6.5 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 970873 - CVE-2013-2141 Kernel: signal: information leak in tkill/tgkill
• BZ - 1023477 - CVE-2013-4470 Kernel: net: memory corruption with UDP_CORK and UFO
• BZ - 1032207 - CVE-2013-6367 kvm: division by zero in apic_get_tmcct()
• BZ - 1032210 - CVE-2013-6368 kvm: cross page vapic_addr access

CVEs

• CVE-2013-2141
• CVE-2013-6367
• CVE-2013-4470
• CVE-2013-6368

References