RHSA-2018:2763 - Security Advisory

Topic

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 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.

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):

• kernel: Integer overflow in Linux's create_elf_tables function (CVE-2018-14634)

For more details about the security issue(s), including the impact, a CVSS score, and other related information, refer to the CVE page(s) listed in the References section.

Red Hat would like to thank Qualys Research Labs for reporting this issue.

Bug Fix(es):

• The kernel-rt packages have been upgraded to the 3.10.0-862.14.3 source tree, which provides a number of bug fixes over the previous version. (BZ#1616429)
• Previously, preemption was enabled too early after a context switch. If a task was migrated to another CPU after a context switch, a mismatch between CPU and runqueue during load balancing sometimes occurred. Consequently, a runnable task on an idle CPU failed to run, and the operating system became unresponsive. This update disables preemption in the schedule_tail() function. As a result, CPU migration during post-schedule processing no longer occurs, which prevents the above mismatch. The operating system no longer hangs due to this bug. (BZ#1617941)

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

• Red Hat Enterprise Linux for Real Time 7 x86_64
• Red Hat Enterprise Linux for Real Time for NFV 7 x86_64

Fixes

• BZ - 1616429 - kernel-rt: update to the RHEL7.5.z batch#4 source tree
• BZ - 1617941 - RT system hang due to wrong of rq's nr_running [rhel-7.5.z]
• BZ - 1624498 - CVE-2018-14634 kernel: Integer overflow in Linux's create_elf_tables function

CVEs

• CVE-2018-14634

References

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