[RHSA-2022:0629-01] Important: kernel-rt security and bug fix update

Tue Feb 22 22:15:27 UTC 2022

An update for kernel-rt is now available for Red Hat Enterprise Linux 8.2
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. 8.2) - x86_64
Red Hat Enterprise Linux Real Time for NFV EUS (v. 8.2) - 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 unix_gc() which could result in a local
privilege escalation (CVE-2021-0920)

* kernel: use-after-free in RDMA listen() (CVE-2021-4028)

* kernel: xfs: raw block device data leak in XFS_IOC_ALLOCSP IOCTL
(CVE-2021-4155)

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):

* kernnel-rt-debug: do not call blocking ops when !TASK_RUNNING; state=1
set at [<0000000050e86018>] handle_userfault+0x530/0x1820 (BZ#2029420)

* kernel-rt: update RT source tree to the latest RHEL-8.2.z15 Batch
(BZ#2046275)

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/):

2027201 - CVE-2021-4028 kernel: use-after-free in RDMA listen()
2031930 - CVE-2021-0920 kernel: Use After Free in unix_gc() which could result in a local privilege escalation
2034813 - CVE-2021-4155 kernel: xfs: raw block device data leak in XFS_IOC_ALLOCSP IOCTL

6. Package List:

Red Hat Enterprise Linux Real Time for NFV EUS (v. 8.2):

Source:
kernel-rt-4.18.0-193.75.1.rt13.125.el8_2.src.rpm

x86_64:
kernel-rt-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-core-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-core-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-debuginfo-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-devel-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-kvm-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-modules-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-modules-extra-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debuginfo-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debuginfo-common-x86_64-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-devel-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-kvm-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-modules-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-modules-extra-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm

Red Hat Enterprise Linux Real Time EUS (v. 8.2):

Source:
kernel-rt-4.18.0-193.75.1.rt13.125.el8_2.src.rpm

x86_64:
kernel-rt-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-core-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-core-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-debuginfo-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-devel-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-modules-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debug-modules-extra-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debuginfo-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-debuginfo-common-x86_64-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-devel-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-modules-4.18.0-193.75.1.rt13.125.el8_2.x86_64.rpm
kernel-rt-modules-extra-4.18.0-193.75.1.rt13.125.el8_2.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-2021-0920
https://access.redhat.com/security/cve/CVE-2021-4028
https://access.redhat.com/security/cve/CVE-2021-4155
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 2022 Red Hat, Inc.
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