Synopsis

Important: kernel security and bug fix update

Type/Severity

Security Advisory: Important

Topic

Updated kernel packages that fix multiple security issues and several bugs
are now available for Red Hat Enterprise Linux 6.4 Extended Update Support.

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 IPv6 implementation

handled certain UDP packets when the UDP Fragmentation Offload (UFO)
feature was enabled. A remote attacker could use this flaw to crash the
system or, potentially, escalate their privileges on the system.
(CVE-2013-4387, Important)

• 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)

• A buffer overflow flaw was found in the way the qeth_snmp_command()

function in the Linux kernel's QETH network device driver implementation
handled SNMP IOCTL requests with an out-of-bounds length. A local,
unprivileged user could use this flaw to crash the system or, potentially,
escalate their privileges on the system. (CVE-2013-6381, Important)

• It was found that the fix for CVE-2012-2375 released via RHSA-2012:1580

accidentally removed a check for small-sized result buffers. A local,
unprivileged user with access to an NFSv4 mount with ACL support could use
this flaw to crash the system or, potentially, escalate their privileges on
the system. (CVE-2013-4591, Moderate)

• A format string flaw was found in the Linux kernel's block layer.

A privileged, local user could potentially use this flaw to escalate their
privileges to kernel level (ring0). (CVE-2013-2851, Low)

Red Hat would like to thank Hannes Frederic Sowa for reporting
CVE-2013-4470, Andrew Honig of Google for reporting CVE-2013-6367 and
CVE-2013-6368, and Kees Cook for reporting CVE-2013-2851.

This update also fixes several bugs. 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. 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 for x86_64 - Extended Update Support 6.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.4 i386
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.4 ppc64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.4 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.4 i386
• Red Hat Gluster Storage Server for On-premise 2.1 x86_64
• Red Hat Storage for Public Cloud (via RHUI) 2.1 x86_64
• Red Hat Enterprise Linux EUS Compute Node 6.4 x86_64
• Red Hat Enterprise Linux Server - AUS 6.4 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.4 s390x

Fixes

• BZ - 969515 - CVE-2013-2851 kernel: block: passing disk names as format strings
• BZ - 1011927 - CVE-2013-4387 Kernel: net: IPv6: panic when UFO=On for an interface
• BZ - 1023477 - CVE-2013-4470 Kernel: net: memory corruption with UDP_CORK and UFO
• BZ - 1031678 - CVE-2013-4591 kernel: nfs: missing check for buffer length in __nfs4_get_acl_uncached
• BZ - 1032207 - CVE-2013-6367 kvm: division by zero in apic_get_tmcct()
• BZ - 1032210 - CVE-2013-6368 kvm: cross page vapic_addr access
• BZ - 1033600 - CVE-2013-6381 Kernel: qeth: buffer overflow in snmp ioctl

CVEs

• CVE-2013-2851
• CVE-2013-4387
• CVE-2013-4591
• CVE-2013-6367
• CVE-2013-4470
• CVE-2013-6368
• CVE-2013-6381

References