6.9 - RHSA-2014:1365

Problem Description:

Updated kernel packages that fix one security issue 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. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available from the CVE link in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Compute Node Optional EUS (v. 6.4) - x86_64 Red Hat Enterprise Linux HPC Node EUS (v. 6.4) - noarch, x86_64 Red Hat Enterprise Linux Server EUS (v. 6.4) - i386, noarch, ppc64, s390x, x86_64 Red Hat Enterprise Linux Server Optional EUS (v. 6.4) - i386, ppc64, s390x, x86_64

3. 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 futex subsystem handled reference counting when requeuing futexes during futex_wait(). A local, unprivileged user could use this flaw to zero out the reference counter of an inode or an mm struct that backs up the memory area of the futex, which could lead to a use-after-free flaw, resulting in a system crash or, potentially, privilege escalation. (CVE-2014-0205, Important)

The security impact of this issue was discovered by Mateusz Guzik of Red Hat.

This update also fixes the following bugs:

* A rare race between the file system unmount code and the file system notification code could lead to a kernel panic. With this update, a series of patches has been applied to the kernel to prevent this problem. (BZ#1130628)

* Previously, recovery of a double-degraded RAID6 array could, under certain circumstances, result in data corruption. This could happen because the md driver was using an optimization that is safe to use only for single-degraded arrays. This update ensures that this optimization is skipped during the recovery of double-degraded RAID6 arrays. (BZ#1131410)

* Later Intel CPUs added a new "Condition Changed" bit to the MSR_CORE_PERF_GLOBAL_STATUS register. Previously, the kernel falsely assumed that this bit indicates a performance interrupt, which prevented other NMI handlers from running and executing. To fix this problem, a patch has been applied to the kernel to ignore this bit in the perf code, enabling other NMI handlers to run. (BZ#1134695)

* Previously, certain network device drivers did not accept ethtool commands right after they were mounted. As a consequence, the current setting of the specified device driver was not applied and an error message was returned. The ETHTOOL_DELAY variable has been added, which makes sure the ethtool utility waits for some time before it tries to apply the options settings, thus fixing the bug. (BZ#1138300)

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.

4. 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.

5. Bugs fixed (https://bugzilla.redhat.com/):

1094455 - CVE-2014-0205 kernel: futex: refcount issue in case of requeue