[RHSA-2021:4088-01] Important: kernel-rt security and bug fix update

Tue Nov 2 09:53:16 UTC 2021

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 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 (v. 8) - x86_64
Red Hat Enterprise Linux Real Time for NFV (v. 8) - 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: use-after-free in drivers/infiniband/core/ucma.c ctx
use-after-free (CVE-2020-36385)

* kernel: out-of-bounds write due to a heap buffer overflow in
__hidinput_change_resolution_multipliers() of hid-input.c (CVE-2021-0512)

* kernel: SVM nested virtualization issue in KVM (VMLOAD/VMSAVE)
(CVE-2021-3656)

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.z source tree
(BZ#2004117)

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/):

1974319 - CVE-2020-36385 kernel: use-after-free in drivers/infiniband/core/ucma.c ctx use-after-free
1974491 - CVE-2021-0512 kernel: out-of-bounds write due to a heap buffer overflow in __hidinput_change_resolution_multipliers() of hid-input.c
1983988 - CVE-2021-3656 kernel: SVM nested virtualization issue in KVM (VMLOAD/VMSAVE)

6. Package List:

Red Hat Enterprise Linux Real Time for NFV (v. 8):

Source:
kernel-rt-4.18.0-305.25.1.rt7.97.el8_4.src.rpm

x86_64:
kernel-rt-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-core-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-core-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-debuginfo-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-devel-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-kvm-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-modules-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-modules-extra-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debuginfo-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debuginfo-common-x86_64-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-devel-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-kvm-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-modules-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-modules-extra-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm

Red Hat Enterprise Linux Real Time (v. 8):

Source:
kernel-rt-4.18.0-305.25.1.rt7.97.el8_4.src.rpm

x86_64:
kernel-rt-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-core-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-core-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-debuginfo-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-devel-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-modules-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debug-modules-extra-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debuginfo-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-debuginfo-common-x86_64-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-devel-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-modules-4.18.0-305.25.1.rt7.97.el8_4.x86_64.rpm
kernel-rt-modules-extra-4.18.0-305.25.1.rt7.97.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-2020-36385
https://access.redhat.com/security/cve/CVE-2021-0512
https://access.redhat.com/security/cve/CVE-2021-3656
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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