RHSA-2018:1967 - Security Advisory

Topic

An update for kernel-alt is now available for Red Hat Enterprise Linux 7.

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-alt packages provide the Linux kernel version 4.x.

Security Fix(es):

• An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of Load & Store instructions (a commonly used performance optimization). It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory read from address to which a recent memory write has occurred may see an older value and subsequently 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 read privileged memory by conducting targeted cache side-channel attacks. (CVE-2018-3639, PowerPC)
• This release also includes next iteration of the CVE-2017-5715 mitigation that includes the SMCCC (Secure Monitor Call Calling Convention) 1.1 support. (CVE-2017-5715, ARM)

Red Hat would like to thank Google Project Zero for reporting CVE-2017-5715 and Ken Johnson (Microsoft Security Response Center) and Jann Horn (Google Project Zero) for reporting CVE-2018-3639.

Bug Fix(es):

These updated kernel-alt packages include numerous bug fixes. Space precludes documenting all of the bug fixes in this advisory. See the descriptions in the related Knowledge Article: https://access.redhat.com/articles/3485851

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 ARM 64 7 aarch64
• Red Hat Enterprise Linux for Power 9 7 ppc64le
• Red Hat Enterprise Linux for IBM System z (Structure A) 7 s390x

Fixes

• BZ - 1519780 - CVE-2017-5715 hw: cpu: speculative execution branch target injection
• BZ - 1566890 - CVE-2018-3639 hw: cpu: speculative store bypass

CVEs

• CVE-2017-5715
• CVE-2018-3639

References

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/security/cve/CVE-2018-3639
• https://access.redhat.com/security/cve/CVE-2017-5715
• https://access.redhat.com/articles/3485851