Synopsis

Moderate: kernel-rt security and bug fix update

Type/Severity

Security Advisory: Moderate

Topic

An update for kernel-rt is now available for Red Hat Enterprise MRG 2.

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.

Description

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 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#1459275)
  
• The kernel-rt packages have been upgraded to version 3.10.0-693.11.1.rt56.595, which provides a number of security and bug fixes over the previous version. (BZ#1500036)
  
• 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#1509021)

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.

Affected Products

• MRG Realtime 2 x86_64

Fixes

• BZ - 1463311 - CVE-2017-1000380 kernel: information leak due to a data race in ALSA timer
• BZ - 1500036 - update the MRG 2.5.z 3.10 kernel-rt sources
• BZ - 1509021 - [MRG-RT] Possible regression with NOHZ_FULL & rt_mutexes in IRQ (BZ1250649)

CVEs

• CVE-2017-1000380

References

• https://access.redhat.com/security/updates/classification/#moderate

MRG Realtime 2

SRPM
kernel-rt-3.10.0-693.11.1.rt56.597.el6rt.src.rpm	SHA-256: 0a03ec56ebfe2468c93b84647295dc5d920e73b7af8045714791466d198c4798
x86_64
kernel-rt-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: 6d34aa89576b7824c28de76146cb98b2e0a78531dbb4e29dac8445319fb2ecb3
kernel-rt-debug-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: fa037bd44283ea59810c33b8fdf72e313495d0620a4f0885d55989a026353e9d
kernel-rt-debug-debuginfo-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: 725acb49d3895d3d9f10617d89f687f6cb512983ebb0f3dda28a01d526f86d8e
kernel-rt-debug-devel-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: 6272ce9c7b66c1438208dae8f71702466a48bb65908f05033d754549e07aa052
kernel-rt-debuginfo-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: 66e2ccf0e0280f54f9fbe85b05745cb735b620fb86b0eda36f5e71393696bacb
kernel-rt-debuginfo-common-x86_64-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: 5b470ab8a71a758b5ac98e3015db1b763f21d464bc09110d132236363ed968d4
kernel-rt-devel-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: f668b506bd24440a055f1a43e351350cbf636116650d5045e9f67a2de667cade
kernel-rt-doc-3.10.0-693.11.1.rt56.597.el6rt.noarch.rpm	SHA-256: c481504dfe1460a6613e4d91e7dc221700f725e2de8f23107724df54253b455f
kernel-rt-firmware-3.10.0-693.11.1.rt56.597.el6rt.noarch.rpm	SHA-256: 650dc2c4eb737c469a097ae7aed46730a440c9ff447053464eddfb6c13e85476
kernel-rt-trace-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: 14124958823d105070b8cb5cbb27a3013af498b654dc2df677436e5cb23edf4a
kernel-rt-trace-debuginfo-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: 1480db464d03784c96c59113500e02118a26fd64ad9aa3e43de9396e7e539c67
kernel-rt-trace-devel-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: d61f76547fc0e8609d75ca48b57edbe67aa59780917dec78ed11fbaa2fd55e38
kernel-rt-vanilla-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: e6667558c7e45250519fa69a5fb287d7ec755d15dc263e04f4e9c6c150f39482
kernel-rt-vanilla-debuginfo-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: 79c07702ddd04230e93681721305d39003118a3f439cb4c33a4e7719db9f5320
kernel-rt-vanilla-devel-3.10.0-693.11.1.rt56.597.el6rt.x86_64.rpm	SHA-256: cc5cfa28ba927bbd92fa2f3f708bbfabc7991709b3909f96b397e5921b2e1f30