[RHSA-2019:1183-01] Important: qemu-kvm security update

Tue May 14 19:11:33 UTC 2019

An update for qemu-kvm is now available for Red Hat Enterprise Linux 7.5
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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.5) - x86_64
Red Hat Enterprise Linux Server EUS (v. 7.5) - x86_64

3. Description:

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):

* A flaw was found in the implementation of the "fill buffer", a mechanism
used by modern CPUs when a cache-miss is made on L1 CPU cache. If an
attacker can generate a load operation that would create a page fault, the
execution will continue speculatively with incorrect data from the fill
buffer while the data is fetched from higher level caches. This response
time can be measured to infer data in the fill buffer. (CVE-2018-12130)

* Modern Intel microprocessors implement hardware-level micro-optimizations
to improve the performance of writing data back to CPU caches. The write
operation is split into STA (STore Address) and STD (STore Data)
sub-operations. These sub-operations allow the processor to hand-off
address generation logic into these sub-operations for optimized writes.
Both of these sub-operations write to a shared distributed processor
structure called the 'processor store buffer'. As a result, an unprivileged
attacker could use this flaw to read private data resident within the CPU's
processor store buffer. (CVE-2018-12126)

* Microprocessors use a ‘load port’ subcomponent to perform load operations
from memory or IO. During a load operation, the load port receives data
from the memory or IO subsystem and then provides the data to the CPU
registers and operations in the CPU’s pipelines. Stale load operations
results are stored in the 'load port' table until overwritten by newer
operations. Certain load-port operations triggered by an attacker can be
used to reveal data about previous stale requests leaking data back to the
attacker via a timing side-channel. (CVE-2018-12127)

* Uncacheable memory on some microprocessors utilizing speculative
execution may allow an authenticated user to potentially enable information
disclosure via a side channel with local access. (CVE-2019-11091)

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.

4. 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.

5. Bugs fixed (https://bugzilla.redhat.com/):

1646781 - CVE-2018-12126 hardware: Microarchitectural Store Buffer Data Sampling (MSBDS)
1646784 - CVE-2018-12130 hardware: Microarchitectural Fill Buffer Data Sampling (MFBDS)
1667782 - CVE-2018-12127 hardware: Micro-architectural Load Port Data Sampling - Information Leak (MLPDS)
1705312 - CVE-2019-11091 hardware: Microarchitectural Data Sampling Uncacheable Memory (MDSUM)

6. Package List:

Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.5):

Source:
qemu-kvm-1.5.3-156.el7_5.7.src.rpm

x86_64:
qemu-img-1.5.3-156.el7_5.7.x86_64.rpm
qemu-kvm-1.5.3-156.el7_5.7.x86_64.rpm
qemu-kvm-common-1.5.3-156.el7_5.7.x86_64.rpm
qemu-kvm-debuginfo-1.5.3-156.el7_5.7.x86_64.rpm
qemu-kvm-tools-1.5.3-156.el7_5.7.x86_64.rpm

Red Hat Enterprise Linux Server EUS (v. 7.5):

Source:
qemu-kvm-1.5.3-156.el7_5.7.src.rpm

x86_64:
qemu-img-1.5.3-156.el7_5.7.x86_64.rpm
qemu-kvm-1.5.3-156.el7_5.7.x86_64.rpm
qemu-kvm-common-1.5.3-156.el7_5.7.x86_64.rpm
qemu-kvm-debuginfo-1.5.3-156.el7_5.7.x86_64.rpm
qemu-kvm-tools-1.5.3-156.el7_5.7.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/

7. References:

https://access.redhat.com/security/cve/CVE-2018-12126
https://access.redhat.com/security/cve/CVE-2018-12127
https://access.redhat.com/security/cve/CVE-2018-12130
https://access.redhat.com/security/cve/CVE-2019-11091
https://access.redhat.com/security/vulnerabilities/mds
https://access.redhat.com/security/updates/classification/#important

8. Contact:

The Red Hat security contact is <secalert at redhat.com>. More contact
details at https://access.redhat.com/security/team/contact/

Copyright 2019 Red Hat, Inc.
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