RHSA-2014:1943 - Security Advisory

Topic

Updated kernel-rt packages that fix three security issues, several bugs,
and add various enhancements are now available for Red Hat Enterprise MRG
2.5.

Red Hat Product Security 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-rt packages contain the Linux kernel, the core of any Linux
operating system.

A denial of service flaw was found in the way the Linux kernel's XFS file
system implementation ordered directory hashes under certain conditions.
A local attacker could use this flaw to corrupt the file system by creating
directories with colliding hash values, potentially resulting in a system
crash. (CVE-2014-7283, Moderate)

An out-of-bounds memory access flaw was found in the syscall tracing
functionality of the Linux kernel's perf subsystem. A local, unprivileged
user could use this flaw to crash the system. (CVE-2014-7825, Moderate)

An out-of-bounds memory access flaw was found in the syscall tracing
functionality of the Linux kernel's ftrace subsystem. On a system with
ftrace syscall tracing enabled, a local, unprivileged user could use this
flaw to crash the system, or escalate their privileges. (CVE-2014-7826,
Moderate)

Red Hat would like to thank Robert Święcki for reporting CVE-2014-7825 and
CVE-2014-7826.

The kernel-rt packages have been upgraded to upstream version 3.10.58,
which provides a number of bug fixes and enhancements over the previous
version. (BZ#1158105)

This update also fixes the following bugs:

• Automatic NUMA balancing on a low priority thread could cause memory

contention with a high priority thread running in the same process.
This contention could trigger poor realtime performance on the system.
In order to avoid this potential memory contention, the MRG Realtime kernel
now disables NUMA_BALANCING_DEFAULT_ENABLED. (BZ#1158940)

• When tracing a bug, WARN*() functions could flood the ring buffer making

the trace useless or even overflowing the ring buffer. To address this
issue, a traceoff_on_warning option was added to the kernel command line
and as a sysctl option. This option disables the writing of the warning
messages to the ring buffer, which results in a cleaner trace for
debugging. (BZ#1155200)

In addition, this update adds the following enhancement:

• Support for XHCI (USB 3) is now enabled in the MRG Realtime kernel.

(BZ#1134095)

All kernel-rt users are advised to upgrade to these updated packages, which
contain 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/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

• MRG Realtime 2 x86_64

Fixes

• BZ - 1134095 - Enable XHCI (USB 3.0) for MRG
• BZ - 1148777 - CVE-2014-7283 kernel: xfs: directory hash ordering denial of service
• BZ - 1158105 - rebase to latest upstream stable 3.10 kernel
• BZ - 1161565 - CVE-2014-7825 CVE-2014-7826 kernel: insufficient syscall number validation in perf and ftrace subsystems

CVEs

• CVE-2014-7283
• CVE-2014-7826
• CVE-2014-7825

References

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