Synopsis

Important: kernel-rt security and bug fix update

Type/Severity

Security Advisory: Important

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):

• An integer overflow flaw was found in the way the Linux kernel's networking subsystem processed TCP Selective Acknowledgment (SACK) segments. While processing SACK segments, the Linux kernel's socket buffer (SKB) data structure becomes fragmented. Each fragment is about TCP maximum segment size (MSS) bytes. To efficiently process SACK blocks, the Linux kernel merges multiple fragmented SKBs into one, potentially overflowing the variable holding the number of segments. A remote attacker could use this flaw to crash the Linux kernel by sending a crafted sequence of SACK segments on a TCP connection with small value of TCP MSS, resulting in a denial of service (DoS). (CVE-2019-11477)
  
• kernel: lack of check for mmap minimum address in expand_downwards in mm/mmap.c leads to NULL pointer dereferences exploit on non-SMAP platforms (CVE-2019-9213)
  
• Kernel: tcp: excessive resource consumption while processing SACK blocks allows remote denial of service (CVE-2019-11478)
  
• Kernel: tcp: excessive resource consumption for TCP connections with low MSS allows remote denial of service (CVE-2019-11479)
  

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 to the RHEL8.0.z batch#1 source tree (BZ#1704955)

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 - 1686136 - CVE-2019-9213 kernel: lack of check for mmap minimum address in expand_downwards in mm/mmap.c leads to NULL pointer dereferences exploit on non-SMAP platforms
• BZ - 1719123 - CVE-2019-11477 Kernel: tcp: integer overflow while processing SACK blocks allows remote denial of service
• BZ - 1719128 - CVE-2019-11478 Kernel: tcp: excessive resource consumption while processing SACK blocks allows remote denial of service
• BZ - 1719129 - CVE-2019-11479 Kernel: tcp: excessive resource consumption for TCP connections with low MSS allows remote denial of service

CVEs

• CVE-2019-9213
• CVE-2019-11477
• CVE-2019-11478
• CVE-2019-11479

References

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

Red Hat Enterprise Linux for Real Time 8

SRPM
kernel-rt-4.18.0-80.4.2.rt9.152.el8_0.src.rpm	SHA-256: b3dc961855180abb8c0e68c3350147f25b75e8342342f7563b41b5e8798bcb3e
x86_64
kernel-rt-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 2e427a606eb5f97219922234cabb0c84a077273aeaedb285e4533f075a035cf0
kernel-rt-core-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: e3902c9e793f49d72f74a628ab74b50676437897b41e7e895d507177865ad15b
kernel-rt-debug-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: d7a7583302741bb482ac4095496b1ed95204cd4f1d898351c679a32f144417f2
kernel-rt-debug-core-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 9e42d195bd918922e24989d27fd56cbc87f0d417c446381cf3f8aea17ca118ac
kernel-rt-debug-debuginfo-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: ff87fb44ae2399916e4a2a790d2edb0b04561fea57770ada11615efcbc6c330e
kernel-rt-debug-devel-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: d4d1c94ca214866daa7758ef802b51b4196d7a849a720dc0ac9cbd612dc34c9b
kernel-rt-debug-kvm-debuginfo-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 2f4976468dc73c9983f5daf2ec833f475c325146a3d38d227b638b1d7659052a
kernel-rt-debug-modules-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: e5833180c3df3b48e95b37c83599b517cd318fdfe37982dd1df9bb680cca2af9
kernel-rt-debug-modules-extra-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 8f6642845c3f2a92843d43b6a1d2371530a420fb7c09ff2915d652796d04c63d
kernel-rt-debuginfo-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 4e31ebb1fc6610c84937aee18d408e1c862dfaa48262ef765029caf504a73742
kernel-rt-debuginfo-common-x86_64-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: e47ced575d1cc77fe76c64713a3d73cf4a23452e0ce1b628b2e255e24dd8a87b
kernel-rt-devel-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 5c1961df286c0b8b8a9a5486c1d07e79a8c2f6b8f64aa996621caeff87dbe297
kernel-rt-kvm-debuginfo-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: ba7cd8dc648a4392201848699672a44d45d44446b622b2d0d40bba5774c7ca23
kernel-rt-modules-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 264b7275d9750d7326f5bcdcd4fc9f5aa46ad559857483c9faea199e1cf11edd
kernel-rt-modules-extra-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 703072519a3ffe91ba85b722853d959f3392a99e264c3a641e6c19f173edce11

Red Hat Enterprise Linux for Real Time for NFV 8

SRPM
kernel-rt-4.18.0-80.4.2.rt9.152.el8_0.src.rpm	SHA-256: b3dc961855180abb8c0e68c3350147f25b75e8342342f7563b41b5e8798bcb3e
x86_64
kernel-rt-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 2e427a606eb5f97219922234cabb0c84a077273aeaedb285e4533f075a035cf0
kernel-rt-core-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: e3902c9e793f49d72f74a628ab74b50676437897b41e7e895d507177865ad15b
kernel-rt-debug-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: d7a7583302741bb482ac4095496b1ed95204cd4f1d898351c679a32f144417f2
kernel-rt-debug-core-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 9e42d195bd918922e24989d27fd56cbc87f0d417c446381cf3f8aea17ca118ac
kernel-rt-debug-debuginfo-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: ff87fb44ae2399916e4a2a790d2edb0b04561fea57770ada11615efcbc6c330e
kernel-rt-debug-devel-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: d4d1c94ca214866daa7758ef802b51b4196d7a849a720dc0ac9cbd612dc34c9b
kernel-rt-debug-kvm-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 959037cb189c34a93f3827c0d7f49d1bb69e24cc6081aa30963a71fce403e456
kernel-rt-debug-kvm-debuginfo-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 2f4976468dc73c9983f5daf2ec833f475c325146a3d38d227b638b1d7659052a
kernel-rt-debug-modules-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: e5833180c3df3b48e95b37c83599b517cd318fdfe37982dd1df9bb680cca2af9
kernel-rt-debug-modules-extra-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 8f6642845c3f2a92843d43b6a1d2371530a420fb7c09ff2915d652796d04c63d
kernel-rt-debuginfo-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 4e31ebb1fc6610c84937aee18d408e1c862dfaa48262ef765029caf504a73742
kernel-rt-debuginfo-common-x86_64-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: e47ced575d1cc77fe76c64713a3d73cf4a23452e0ce1b628b2e255e24dd8a87b
kernel-rt-devel-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 5c1961df286c0b8b8a9a5486c1d07e79a8c2f6b8f64aa996621caeff87dbe297
kernel-rt-kvm-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 9f1ca61cf7b467004510d84c5b79e3ed21d40c4eedd0a5b1c0e10f8edd9be87b
kernel-rt-kvm-debuginfo-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: ba7cd8dc648a4392201848699672a44d45d44446b622b2d0d40bba5774c7ca23
kernel-rt-modules-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 264b7275d9750d7326f5bcdcd4fc9f5aa46ad559857483c9faea199e1cf11edd
kernel-rt-modules-extra-4.18.0-80.4.2.rt9.152.el8_0.x86_64.rpm	SHA-256: 703072519a3ffe91ba85b722853d959f3392a99e264c3a641e6c19f173edce11