[RHSA-2021:4648-04] Important: kernel-rt security and bug fix update

Mon Nov 15 14:40:55 UTC 2021

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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Real Time EUS (v.8.4) - x86_64
Red Hat Enterprise Linux Real Time for NFV EUS (v.8.4) - x86_64

3. 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)

4. 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.

5. Bugs fixed (https://bugzilla.redhat.com/):

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

6. Package List:

Red Hat Enterprise Linux Real Time for NFV EUS (v.8.4):

Source:
kernel-rt-4.18.0-305.28.1.rt7.100.el8_4.src.rpm

x86_64:
kernel-rt-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-core-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-core-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-debuginfo-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-devel-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-kvm-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-modules-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-modules-extra-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debuginfo-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debuginfo-common-x86_64-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-devel-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-kvm-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-modules-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-modules-extra-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm

Red Hat Enterprise Linux Real Time EUS (v.8.4):

Source:
kernel-rt-4.18.0-305.28.1.rt7.100.el8_4.src.rpm

x86_64:
kernel-rt-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-core-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-core-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-debuginfo-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-devel-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-modules-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debug-modules-extra-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debuginfo-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-debuginfo-common-x86_64-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-devel-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-modules-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm
kernel-rt-modules-extra-4.18.0-305.28.1.rt7.100.el8_4.x86_64.rpm

These packages are GPG signed by Red Hat for security.  Our key and
details on how to verify the signature are available from
https://access.redhat.com/security/team/key/

7. References:

https://access.redhat.com/security/cve/CVE-2021-20317
https://access.redhat.com/security/cve/CVE-2021-28950
https://access.redhat.com/security/cve/CVE-2021-43267
https://access.redhat.com/security/updates/classification/#important

8. Contact:

The Red Hat security contact is <secalert at redhat.com>. More contact
details at https://access.redhat.com/security/team/contact/

Copyright 2021 Red Hat, Inc.
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