RHEL 6 : kernel-rt (RHSA-2016:1532)

This script is Copyright (C) 2016-2017 Tenable Network Security, Inc.


Synopsis :

The remote Red Hat host is missing one or more security updates.

Description :

An update for kernel-rt is now available for Red Hat Enterprise MRG
2.5.

Red Hat Product Security has rated this update as having a security
impact of Important. A Common Vulnerability Scoring System (CVSS) base
score, which gives a detailed severity rating, is available for each
vulnerability from the CVE link(s) in the References section.

The kernel-rt packages provide the Real Time Linux Kernel, which
enables fine-tuning for systems with extremely high determinism
requirements.

* A flaw was found in the Linux kernel's keyring handling code, where
in key_reject_and_link() an uninitialised variable would eventually
lead to arbitrary free address which could allow attacker to use a
use-after-free style attack. (CVE-2016-4470, Important)

* The ovl_setattr function in fs/overlayfs/inode.c in the Linux kernel
through 4.3.3 attempts to merge distinct setattr operations, which
allows local users to bypass intended access restrictions and modify
the attributes of arbitrary overlay files via a crafted application.
(CVE-2015-8660, Moderate)

Red Hat would like to thank Nathan Williams for reporting
CVE-2015-8660. The CVE-2016-4470 issue was discovered by David Howells
(Red Hat Inc.).

The kernel-rt packages have been upgraded to upstream version
3.10.0-327.rt56.194.el6rt, which provides a number of bug fixes over
the previous version. (BZ#1343658)

This update also fixes the following bugs :

* Previously, use of the get/put_cpu_var() function in function
refill_stock() from the memcontrol cgroup code lead to a 'scheduling
while atomic' warning. With this update, refill_stock() uses the
get/put_cpu_light() function instead, and the warnings no longer
appear. (BZ#1348710)

* Prior to this update, if a real time task pinned to a given CPU was
taking 100% of the CPU time, then calls to the lru_add_drain_all()
function on other CPUs blocked for an undetermined amount of time.
This caused latencies and undesired side effects. With this update,
lru_add_drain_all() has been changed to drain the LRU pagevecs of
remote CPUs. (BZ#1348711)

See also :

https://www.redhat.com/security/data/cve/CVE-2015-8660.html
https://www.redhat.com/security/data/cve/CVE-2016-4470.html
http://rhn.redhat.com/errata/RHSA-2016-1532.html

Solution :

Update the affected packages.

Risk factor :

High / CVSS Base Score : 7.2
(CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C)
CVSS Temporal Score : 6.0
(CVSS2#E:F/RL:OF/RC:ND)
Public Exploit Available : true

Family: Red Hat Local Security Checks

Nessus Plugin ID: 92692 ()

Bugtraq ID:

CVE ID: CVE-2015-8660
CVE-2016-4470

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