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.

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 use-after-free flaw was found in the way the ping_init_sock() function

of the Linux kernel handled the group_info reference counter. A local,
unprivileged user could use this flaw to crash the system or, potentially,
escalate their privileges on the system. (CVE-2014-2851, Important)

• A NULL pointer dereference flaw was found in the rds_ib_laddr_check()

function in the Linux kernel's implementation of Reliable Datagram Sockets
(RDS). A local, unprivileged user could use this flaw to crash the system.
(CVE-2013-7339, Moderate)

• It was found that a remote attacker could use a race condition flaw in

the ath_tx_aggr_sleep() function to crash the system by creating large
network traffic on the system's Atheros 9k wireless network adapter.
(CVE-2014-2672, Moderate)

• A NULL pointer dereference flaw was found in the rds_iw_laddr_check()

function in the Linux kernel's implementation of Reliable Datagram Sockets
(RDS). A local, unprivileged user could use this flaw to crash the system.
(CVE-2014-2678, Moderate)

• A race condition flaw was found in the way the Linux kernel's mac80211

subsystem implementation handled synchronization between TX and STA wake-up
code paths. A remote attacker could use this flaw to crash the system.
(CVE-2014-2706, Moderate)

This update also fixes the following bugs:

• The Completely Fair Scheduler (CFS) did not verify whether the CFS

period timer is running while throttling tasks on the CFS run queue.
Therefore under certain circumstances, the CFS run queue became stuck
because the CFS period timer was inactive and could not be restarted. To
fix this problem, the CFS now restarts the CFS period timer inside the
throttling function if it is inactive. (BZ#1120666)

• A previous change to the SCSI code fixed a race condition that could

occur when removing a SCSI device. However, that change caused performance
degradation because it used a certain function from the block layer code
that was returning different values compared with later versions of the
kernel. This update alters the SCSI code to properly utilize the values
returned by the block layer code. (BZ#1117581)

• If a statically defined gateway became unreachable and its corresponding

neighbor entry entered a FAILED state, the gateway stayed in the FAILED
state even after it became reachable again. This prevented routing of the
traffic through that gateway. This update allows probing such a gateway
automatically and routing the traffic through the gateway again once it
becomes reachable. (BZ#1115262)

• A miscalculation in the "radix_tree" swap encoding corrupted swap area

indexes bigger than 8 by truncating lower bits of swap entries.
Consequently, systems with more than 8 swap areas could trigger a bogus
OOM scenario when swapping out to such a swap area. This update fixes this
problem by reducing a return value of the SWP_TYPE_SHIFT() function and
removing a broken function call from the read_swap_header() function.
(BZ#1099727)

• The automatic route cache rebuilding feature could incorrectly compute

the length of a route hash chain if the cache contained multiple entries
with the same key but a different TOS, mark, or OIF bit. Consequently, the
feature could reach the rebuild limit and disable the routing cache on the
system. This problem is fixed by using a helper function that avoids
counting such duplicate routes. (BZ#1113823)

• When booting a guest in the Hyper-V environment and enough of

Programmable Interval Timer (PIT) interrupts were lost or not injected
into the guest on time, the kernel panicked and the guest failed to boot.
This problem has been fixed by bypassing the relevant PIT check when the
guest is running under the Hyper-V environment. (BZ#1112225)

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 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
• Red Hat Enterprise Linux Server - AUS 6.4 x86_64

Fixes

• BZ - 1079214 - CVE-2013-7339 kernel: net: rds: dereference of a NULL device in rds_ib_laddr_check()
• BZ - 1083246 - CVE-2014-2672 kernel: ath9k: tid->sched race in ath_tx_aggr_sleep()
• BZ - 1083274 - CVE-2014-2678 kernel: net: rds: dereference of a NULL device in rds_iw_laddr_check()
• BZ - 1083512 - CVE-2014-2706 Kernel: net: mac80211: crash dues to AP powersave TX vs. wakeup race
• BZ - 1086730 - CVE-2014-2851 kernel: net: ping: refcount issue in ping_init_sock() function

CVEs

• CVE-2013-7339
• CVE-2014-2672
• CVE-2014-2678
• CVE-2014-2706
• CVE-2014-2851

References