Moderate: kernel security and bug fix update

Synopsis

Moderate: kernel security and bug fix update

Type/Severity

Security Advisory: Moderate

Topic

Updated kernel packages that fix multiple security issues and one bug are
now available for Red Hat Enterprise Linux 5.

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.

• A flaw was found in the way the Linux kernel handled the creation of
  temporary IPv6 addresses. If the IPv6 privacy extension was enabled
  (/proc/sys/net/ipv6/conf/eth0/use_tempaddr is set to '2'), an attacker on
  the local network could disable IPv6 temporary address generation, leading
  to a potential information disclosure. (CVE-2013-0343, Moderate)
  
• An information leak flaw was found in the way Linux kernel's device
  mapper subsystem, under certain conditions, interpreted data written to
  snapshot block devices. An attacker could use this flaw to read data from
  disk blocks in free space, which are normally inaccessible. (CVE-2013-4299,
  Moderate)
  
• An off-by-one flaw was found in the way the ANSI CPRNG implementation in
  the Linux kernel processed non-block size aligned requests. This could lead
  to random numbers being generated with less bits of entropy than expected
  when ANSI CPRNG was used. (CVE-2013-4345, Moderate)
  
• An information leak flaw was found in the way Xen hypervisor emulated the
  OUTS instruction for 64-bit paravirtualized guests. A privileged guest user
  could use this flaw to leak hypervisor stack memory to the guest.
  (CVE-2013-4368, Moderate)
  

Red Hat would like to thank Fujitsu for reporting CVE-2013-4299, Stephan
Mueller for reporting CVE-2013-4345, and the Xen project for reporting
CVE-2013-4368.

This update also fixes the following bug:

• A bug in the GFS2 code prevented glock work queues from freeing
  glock-related memory while the glock memory shrinker repeatedly queued a
  large number of demote requests, for example when performing a simultaneous
  backup of several live GFS2 volumes with a large file count. As a
  consequence, the glock work queues became overloaded which resulted in a
  high CPU usage and the GFS2 file systems being unresponsive for a
  significant amount of time. A patch has been applied to alleviate this
  problem by calling the yield() function after scheduling a certain amount
  of tasks on the glock work queues. The problem can now occur only with
  extremely high work loads. (BZ#1014714)
  

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 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 - 914664 - CVE-2013-0343 kernel: handling of IPv6 temporary addresses
• BZ - 1004233 - CVE-2013-4299 kernel: dm: dm-snapshot data leak
• BZ - 1007690 - CVE-2013-4345 kernel: ansi_cprng: off by one error in non-block size request
• BZ - 1012550 - CVE-2013-4368 xen: information leak through outs instruction emulation (XSA-67)

CVEs

• CVE-2013-4299
• CVE-2013-0343
• CVE-2013-4345
• CVE-2013-4368

References

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