RHSA-2018:0049 - Security Advisory

Topic

An update for ovirt-guest-agent-docker is now available for RHEV 4.X, RHEV-H, and Agents 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 ovirt-guest-agent-docker package provides the guest agent for Red Hat Linux Atomic Host virtual machines. The guest agent allows the Red Hat Virtualization Manager to receive internal guest events and retrieve information such as the IP address and the list of installed applications from the guest. Additionally the guest agent allows the Manager to execute specific commands, such as shut down or reboot, on guest virtual machines.

Security Fix(es):

• An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of instructions (a commonly used performance optimization). There are three primary variants of the issue which differ in the way the speculative execution can be exploited. Variant CVE-2017-5715 triggers the speculative execution by utilizing branch target injection. It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory accesses may cause allocation 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 cross the syscall and guest/host boundaries and read privileged memory by conducting targeted cache side-channel attacks. (CVE-2017-5715)

Note: This is the ovirt-guest-agent-docker side of the CVE-2017-5715 mitigation.

Red Hat would like to thank Google Project Zero for reporting this issue.

Bug Fix(es):

• Previously, during Atomic host shutdown, the container was killed before the Guest Agent had a chance to send 'session-shutdown' message to VDSM host. This is now fixed. (BZ#1427849)

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

Affected Products

• Red Hat Virtualization 4 for RHEL 7 x86_64

Fixes

• BZ - 1427849 - [atomic] The engine starts HA VM if the VM powered off from the guest OS
• BZ - 1519780 - CVE-2017-5715 hw: cpu: speculative execution branch target injection
• BZ - 1524695 - [Rebase] Rebuild of the ovirt-guest-agent container on top of latest RHEL 7.4

CVEs

(none)

References

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/security/vulnerabilities/speculativeexecution
• https://access.redhat.com/solutions/3307851
• https://access.redhat.com/security/cve/CVE-2017-5715