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

High Nessus Plugin ID 92692


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


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)


Update the affected packages.

See Also




Plugin Details

Severity: High

ID: 92692

File Name: redhat-RHSA-2016-1532.nasl

Version: $Revision: 2.5 $

Type: local

Agent: unix

Published: 2016/08/03

Modified: 2017/01/10

Dependencies: 12634

Risk Information

Risk Factor: High


Base Score: 7.2

Temporal Score: 6

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

Temporal Vector: CVSS2#E:F/RL:OF/RC:ND


Base Score: 6.7

Temporal Score: 6.2

Vector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:F/RL:O/RC:X

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:kernel-rt, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-debuginfo, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debuginfo, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debuginfo-common-x86_64, p-cpe:/a:redhat:enterprise_linux:kernel-rt-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-doc, p-cpe:/a:redhat:enterprise_linux:kernel-rt-firmware, p-cpe:/a:redhat:enterprise_linux:kernel-rt-trace, p-cpe:/a:redhat:enterprise_linux:kernel-rt-trace-debuginfo, p-cpe:/a:redhat:enterprise_linux:kernel-rt-trace-devel, p-cpe:/a:redhat:enterprise_linux:kernel-rt-vanilla, p-cpe:/a:redhat:enterprise_linux:kernel-rt-vanilla-debuginfo, p-cpe:/a:redhat:enterprise_linux:kernel-rt-vanilla-devel, cpe:/o:redhat:enterprise_linux:6

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2016/08/02

Exploitable With


Core Impact

Metasploit (Overlayfs Privilege Escalation)

Reference Information

CVE: CVE-2015-8660, CVE-2016-4470

OSVDB: 132260, 140046

RHSA: 2016:1532