RHSA-2021:5241 - Security Advisory

Topic

An update for kernel-rt is now available for Red Hat Enterprise Linux 8.

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):

• kernel: In Overlayfs missing a check for a negative dentry before calling vfs_rename() (CVE-2021-20321)

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

Bug Fix(es):

• kernel-rt: update RT source tree to the RHEL-8.5.z1 source tree (BZ#2023988)
• [rt] RHEL-8.6: disable KASAN, KCSAN and UBSAN for kernel-rt (BZ#2026384)

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 8 x86_64
• Red Hat Enterprise Linux for Real Time for NFV 8 x86_64
• Red Hat Enterprise Linux for Real Time - Telecommunications Update Service 8.8 x86_64
• Red Hat Enterprise Linux for Real Time - Telecommunications Update Service 8.6 x86_64
• Red Hat Enterprise Linux for Real Time for NFV - Telecommunications Update Service 8.8 x86_64
• Red Hat Enterprise Linux for Real Time for NFV - Telecommunications Update Service 8.6 x86_64

Fixes

• BZ - 2013242 - CVE-2021-20321 kernel: In Overlayfs missing a check for a negative dentry before calling vfs_rename()

CVEs

• CVE-2021-20321

References

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