RHEL 7 : kernel-rt (RHSA-2017:3322)

Low Nessus Plugin ID 104950

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 Linux 7.

Red Hat Product Security has rated this update as having a security impact of Moderate. 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.

Security Fix(es) :

* It was found that the timer functionality in the Linux kernel ALSA subsystem is prone to a race condition between read and ioctl system call handlers, resulting in an uninitialized memory disclosure to user space. A local user could use this flaw to read information belonging to other users. (CVE-2017-1000380, Moderate)

Red Hat would like to thank Alexander Potapenko (Google) for reporting this issue.

Bug Fix(es) :

* The kernel-rt packages have been upgraded to the 3.10.0-693.11.1 source tree, which provides a number of bug fixes over the previous version. (BZ# 1500035)

* Previously, the hfi1 driver called the preempt_disable() function to prevent migration on standard Red Hat Enterprise Linux and on Red Hat Enterprise Linux for Real Time. On Red Hat Enterprise Linux for Real Time with the realtime kernel (kernel-rt), calling preempt_disable() triggered a kernel panic. With this update, the kernel-rt code has been modified to use a realtime-specific function call to the preempt_disable_nort() function, which expands to the correct calls based on the kernel that is running. As a result, the hfi1 driver now works correctly on both Red Hat Enterprise Linux kernel and Red Hat Enterprise Linux for Real Time kernel-rt. (BZ# 1507053)

* Previously, the hfi1 driver called the preempt_disable() function to prevent migration on standard Red Hat Enterprise Linux and on Red Hat Enterprise Linux for Real Time. On Red Hat Enterprise Linux for Real Time with the realtime kernel (kernel-rt), calling preempt_disable() triggered a kernel panic. With this update, the kernel-rt code has been modified to use a realtime-specific function call to the preempt_disable_nort() function, which expands to the correct calls based on the kernel that is running. As a result, the hfi1 driver now works correctly on both Red Hat Enterprise Linux kernel and Red Hat Enterprise Linux for Real Time kernel-rt. (BZ# 1507054)

* In the realtime kernel, if the rt_mutex locking mechanism was taken in the interrupt context, the normal priority inheritance protocol incorrectly identified a deadlock, and a kernel panic occurred. This update reverts the patch that added rt_mutex in the interrupt context, and the kernel no longer panics due to this behavior. (BZ#1511382)

Enhancement(s) :

* The current realtime throttling mechanism prevents the starvation of non-realtime tasks by CPU-intensive realtime tasks. When a realtime run queue is throttled, it allows non-realtime tasks to run. If there are not non-realtime tasks, the CPU goes idle. To safely maximize CPU usage by decreasing the CPU idle time, the RT_RUNTIME_GREED scheduler feature has been implemented. When enabled, this feature checks if non-realtime tasks are starving before throttling the realtime task.
The RT_RUNTIME_GREED scheduler option guarantees some run time on all CPUs for the non-realtime tasks, while keeping the realtime tasks running as much as possible. (BZ# 1505158)

Solution

Update the affected packages.

See Also

https://access.redhat.com/errata/RHSA-2017:3322

https://access.redhat.com/security/cve/cve-2017-1000380

Plugin Details

Severity: Low

ID: 104950

File Name: redhat-RHSA-2017-3322.nasl

Version: 3.7

Type: local

Agent: unix

Published: 2017/12/01

Updated: 2019/03/25

Dependencies: 12634, 122878

Risk Information

Risk Factor: Low

CVSS v2.0

Base Score: 2.1

Temporal Score: 1.6

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

Temporal Vector: CVSS2#E:U/RL:OF/RC:C

CVSS v3.0

Base Score: 5.5

Temporal Score: 4.8

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

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-debug-kvm, p-cpe:/a:redhat:enterprise_linux:kernel-rt-debug-kvm-debuginfo, 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-kvm, p-cpe:/a:redhat:enterprise_linux:kernel-rt-kvm-debuginfo, 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-trace-kvm, p-cpe:/a:redhat:enterprise_linux:kernel-rt-trace-kvm-debuginfo, cpe:/o:redhat:enterprise_linux:7

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

Exploit Available: false

Exploit Ease: No known exploits are available

Patch Publication Date: 2017/11/30

Vulnerability Publication Date: 2017/06/17

Reference Information

CVE: CVE-2017-1000380

RHSA: 2017:3322