(RHSA-2019:1946) Important: kernel security, bug fix, and enhancement update

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.