Synopsis
Important: kernel security and bug fix update
Type/Severity
Security Advisory: Important
Topic
An update for kernel 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 packages contain the Linux kernel, the core of any Linux operating system.
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):
- [HPE 8.0 Bug] nvme drive power button does not turn off drive (BZ#1700288)
- RHEL8.0 - hw csum failure seen in dmesg and console (using mlx5/mlx4/Mellanox) (BZ#1700289)
- RHEL8.0 - vfio-ap: add subsystem to matrix device to avoid libudev failures (kvm) (BZ#1700290)
- [FJ8.1 Bug]: Make Fujitsu Erratum 010001 patch work on A64FX v1r0 (BZ#1700901)
- [FJ8.0 Bug]: Fujitsu A64FX processor errata - panic by unknown fault (BZ#1700902)
- RHEL 8.0 Snapshot 4 - nvme create-ns command hangs after creating 20 namespaces on Bolt (NVMe) (BZ#1701140)
- [Cavium/Marvell 8.0 qed] Fix qed_mcp_halt() and qed_mcp_resume() (backporting bug) (BZ#1704184)
- [Intel 8.1 Bug] PBF: Base frequency display fix (BZ#1706739)
- [RHEL8]read/write operation not permitted to /sys/kernel/debug/gcov/reset (BZ#1708100)
- RHEL8.0 - ISST-LTE:pVM:fleetwood:LPM:raylp85:After lpm seeing the console logs on the the lpar at target side (BZ#1708102)
- RHEL8.0 - Backport support for software count cache flush Spectre v2 mitigation (BZ#1708112)
- [Regression] RHEL8.0 - System crashed with one stress-ng-mremap stressor on Boston (kvm host) (BZ#1708617)
- [intel ice Rhel 8 RC1] ethtool -A ethx causes interfaces to go down (BZ#1709433)
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 x86_64 8 x86_64
-
Red Hat Enterprise Linux for IBM z Systems 8 s390x
-
Red Hat Enterprise Linux for Power, little endian 8 ppc64le
-
Red Hat Enterprise Linux for ARM 64 8 aarch64
-
Red Hat CodeReady Linux Builder for x86_64 8 x86_64
-
Red Hat CodeReady Linux Builder for Power, little endian 8 ppc64le
-
Red Hat CodeReady Linux Builder for ARM 64 8 aarch64
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
References
Vulmon