RedHat: RHSA-2018-1656:01 Important: qemu-kvm security update
Summary
Kernel-based Virtual Machine (KVM) is a full virtualization solution for
Linux on a variety of architectures. The qemu-kvm packages provide the
user-space component for running virtual machines that use KVM.
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)
Note: This is the qemu-kvm side of the CVE-2018-3639 mitigation.
Red Hat would like to thank Ken Johnson (Microsoft Security Response
Center) and Jann Horn (Google Project Zero) for reporting this issue.
Summary
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
After installing this update, shut down all running virtual machines. Once
all virtual machines have shut down, start them again for this update to
take effect.
References
https://access.redhat.com/security/cve/CVE-2018-3639 https://access.redhat.com/security/updates/classification/#important https://access.redhat.com/security/vulnerabilities/ssbd
Package List
Red Hat Enterprise Linux Server AUS (v. 6.4):
Source:
qemu-kvm-0.12.1.2-2.355.el6_4.11.src.rpm
x86_64:
qemu-guest-agent-0.12.1.2-2.355.el6_4.11.x86_64.rpm
qemu-img-0.12.1.2-2.355.el6_4.11.x86_64.rpm
qemu-kvm-0.12.1.2-2.355.el6_4.11.x86_64.rpm
qemu-kvm-debuginfo-0.12.1.2-2.355.el6_4.11.x86_64.rpm
qemu-kvm-tools-0.12.1.2-2.355.el6_4.11.x86_64.rpm
Red Hat Enterprise Linux Server Optional AUS (v. 6.4):
x86_64:
qemu-guest-agent-win32-0.12.1.2-2.355.el6_4.11.x86_64.rpm
qemu-kvm-debuginfo-0.12.1.2-2.355.el6_4.11.x86_64.rpm
These packages are GPG signed by Red Hat for security. Our key and
details on how to verify the signature are available from
https://access.redhat.com/security/team/key/
Topic
An update for qemu-kvm is now available for Red Hat Enterprise Linux 6.4Advanced Update Support.Red Hat Product Security has rated this update as having a security impactof Important. A Common Vulnerability Scoring System (CVSS) base score,which gives a detailed severity rating, is available for each vulnerabilityfrom the CVE link(s) in the References section.
Topic
Relevant Releases Architectures
Red Hat Enterprise Linux Server AUS (v. 6.4) - x86_64
Red Hat Enterprise Linux Server Optional AUS (v. 6.4) - x86_64
Bugs Fixed
1566890 - CVE-2018-3639 hw: cpu: speculative store bypass
