Important: kernel-rt security and bug fix update

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 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: improper initialization of the "flags" member of the new pipe_buffer (CVE-2022-0847)
• kernel: Use After Free in unix_gc() which could result in a local privilege escalation (CVE-2021-0920)
• kernel: local privilege escalation by exploiting the fsconfig syscall parameter leads to container breakout (CVE-2021-4154)
• kernel: possible privileges escalation due to missing TLB flush (CVE-2022-0330)
• kernel: remote stack overflow via kernel panic on systems using TIPC may lead to DoS (CVE-2022-0435)
• kernel: cgroups v1 release_agent feature may allow privilege escalation (CVE-2022-0492)
• kernel: failing usercopy allows for use-after-free exploitation (CVE-2022-22942)

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 symbol '__rt_mutex_init' is exported GPL-only in kernel 4.18.0-348.2.1.rt7.132.el8_5 (BZ#2038423)
• kernel-rt: update RT source tree to the RHEL-8.5.z3 source tree (BZ#2045589)

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

Fixes

• BZ - 2031930 - CVE-2021-0920 kernel: Use After Free in unix_gc() which could result in a local privilege escalation
• BZ - 2034514 - CVE-2021-4154 kernel: local privilege escalation by exploiting the fsconfig syscall parameter leads to container breakout
• BZ - 2042404 - CVE-2022-0330 kernel: possible privileges escalation due to missing TLB flush
• BZ - 2044809 - CVE-2022-22942 kernel: failing usercopy allows for use-after-free exploitation
• BZ - 2048738 - CVE-2022-0435 kernel: remote stack overflow via kernel panic on systems using TIPC may lead to DoS
• BZ - 2051505 - CVE-2022-0492 kernel: cgroups v1 release_agent feature may allow privilege escalation
• BZ - 2060795 - CVE-2022-0847 kernel: improper initialization of the "flags" member of the new pipe_buffer

CVEs

• CVE-2021-0920
• CVE-2021-4154
• CVE-2022-0330
• CVE-2022-0435
• CVE-2022-0492
• CVE-2022-0847
• CVE-2022-22942

References

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/security/vulnerabilities/RHSB-2022-002