RHSA-2015:0043 - Security Advisory

Topic

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

Red Hat Product Security 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 SCTP implementation

handled malformed or duplicate Address Configuration Change Chunks
(ASCONF). A remote attacker could use either of these flaws to crash the
system. (CVE-2014-3673, CVE-2014-3687, Important)

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

handled the association's output queue. A remote attacker could send
specially crafted packets that would cause the system to use an excessive
amount of memory, leading to a denial of service. (CVE-2014-3688,
Important)

The CVE-2014-3673 issue was discovered by Liu Wei of Red Hat.

This update also fixes the following bugs:

• When the Baseboard Management Controller (BMC) was reset, the settings

for the ipmi_watchdog driver were not restored correctly causing error 80
to be returned. With this update, Intelligent Platform Management Interface
(IPMI) is reset as expected in the described situation, and the error is no
longer returned. (BZ#1109268)

• Under certain conditions, XFS log flushes could exceed the kernel thread

stack size. As a consequence, a kernel panic occurred on systems using XFS
file systems. This update provides a patch that moves this code path to a
work queue, and therefore the stack overflow no longer occurs. (BZ#1154086)

• Due to a race condition, an attempt to unmount an XFS file system using

the umount command could fail, causing the system to become unresponsive.
The underlying source code has been modified to fix this bug, and the
system no longer hangs in the described situation. (BZ#1158320)

• Previously, the printk_ratelimited() function printed messages which were

supposed to be suppressed, and failed to print messages that were supposed
to be printed. This was caused by the incorrect usage of the __ratelimit()
function. This bug has been fixed with this update, and now
printk_ratelimit() behaves as expected. (BZ#1169401)

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/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 Server - AUS 6.4 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.4 s390x
• 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

Fixes

• BZ - 1147850 - CVE-2014-3673 kernel: sctp: skb_over_panic when receiving malformed ASCONF chunks
• BZ - 1155731 - CVE-2014-3687 kernel: net: sctp: fix panic on duplicate ASCONF chunks
• BZ - 1155745 - CVE-2014-3688 kernel: net: sctp: remote memory pressure from excessive queueing

CVEs

• CVE-2014-3687
• CVE-2014-3673
• CVE-2014-3688

References

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