RHSA-2021:4648 - Security Advisory

Topic

An update for kernel-rt is now available for Red Hat Enterprise Linux 8.4 Extended Update Support.

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: Insufficient validation of user-supplied sizes for the MSG_CRYPTO message type (CVE-2021-43267)
• kernel: timer tree corruption leads to missing wakeup and system freeze (CVE-2021-20317)
• kernel: fuse: stall on CPU can occur because a retry loop continually finds the same bad inode (CVE-2021-28950)

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-8.4.z5 source tree (BZ#2017122)

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 x86_64 - Extended Update Support Extension 8.4 x86_64
• Red Hat Enterprise Linux for Real Time - Telecommunications Update Service 8.4 x86_64
• Red Hat Enterprise Linux for Real Time for NFV - Telecommunications Update Service 8.4 x86_64

Fixes

• BZ - 1941762 - CVE-2021-28950 kernel: fuse: stall on CPU can occur because a retry loop continually finds the same bad inode
• BZ - 2005258 - CVE-2021-20317 kernel: timer tree corruption leads to missing wakeup and system freeze
• BZ - 2020362 - CVE-2021-43267 kernel: Insufficient validation of user-supplied sizes for the MSG_CRYPTO message type

CVEs

• CVE-2021-20317
• CVE-2021-28950
• CVE-2021-43267

References

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