Synopsis

Important: kernel security, bug fix, and enhancement update

Type/Severity

Security Advisory: Important

Topic

An update for kernel is now available for Red Hat Enterprise Linux 7.4 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.

Description

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

• An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of instructions past bounds check. The flaw relies on the presence of a precisely-defined instruction sequence in the privileged code and the fact that memory writes occur to an address which depends on the untrusted value. Such writes cause an update into the microprocessor's data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to influence speculative execution and/or read privileged memory by conducting targeted cache side-channel attacks. (CVE-2018-3693)
• Kernel: kvm: nVMX: L2 guest could access hardware(L0) CR8 register (CVE-2017-12154)
• kernel: net: double-free and memory corruption in get_net_ns_by_id() (CVE-2017-15129)
• kernel: dereferencing NULL payload with nonzero length (CVE-2017-15274)
• kernel: stack-based buffer overflow in chap_server_compute_md5() in iscsi target (CVE-2018-14633)

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):

• ovl_create can return positive retval and crash the host (BZ#1696290)
• THP: Race between MADV_DONTNEED and NUMA hinting node migration code (BZ#1698105)
• RHEL7.6 - Kernel changes for count cache flush Spectre v2 mitigation (BZ#1708543)
• Poor system performance from thundering herd of kworkers competing for mddev->flush_bio ownership (BZ#1712762)
• [RHEL7.7] RAID1 `write-behind` causes a kernel panic (BZ#1712999)

Enhancement(s):

• [Intel 7.5 FEAT] i40evf - Update to latest upstream driver version (BZ#1722774)
• [netdrv] i40e/i40evf: Fix use after free in Rx cleanup path [7.4.z] (BZ#1723831)

Users of kernel are advised to upgrade to these updated packages, which fix these bugs and add these enhancements.

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 - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.4 ppc64
• Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
• Red Hat Enterprise Linux Server - AUS 7.4 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.4 s390x
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.4 ppc64le
• Red Hat Enterprise Linux Server - TUS 7.4 x86_64
• Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.4 ppc64le
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.4 x86_64

Fixes

• BZ - 1491224 - CVE-2017-12154 Kernel: kvm: nVMX: L2 guest could access hardware(L0) CR8 register
• BZ - 1500391 - CVE-2017-15274 kernel: dereferencing NULL payload with nonzero length
• BZ - 1531174 - CVE-2017-15129 kernel: net: double-free and memory corruption in get_net_ns_by_id()
• BZ - 1581650 - CVE-2018-3693 Kernel: speculative bounds check bypass store
• BZ - 1626035 - CVE-2018-14633 kernel: stack-based buffer overflow in chap_server_compute_md5() in iscsi target

CVEs

• CVE-2017-12154
• CVE-2017-15129
• CVE-2017-15274
• CVE-2018-3693
• CVE-2018-14633

References