[Announce] OpenVZ7 Meltdown & Spectre fixes

[Vasily Averin]

OpenVZ project released an updated OpenVZ7 packages.
Read below for more information. Everyone is advised to update.

Changes and Download
====================

This update is equivalent of Virtuozzo 7 update 6 hotfix 3 (7.0.6-710)

This update provides a new Virtuozzo 7.0 kernel 3.10.0-693.11.6.vz7.40.4 that is a rebase to the Red Hat Enterprise Linux 7 kernel 3.10.0-693.11.6.el7. The rebase fixes an industry-wide issue that 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. NOTE: This issue is present in hardware and cannot be fully fixed via software update. The updated kernel packages provide software mitigation for this hardware issue at a cost of potential performance penalty. Please refer to References section for further information about this issue and the performance impact. In this update mitigations for x86-64 architecture are provided.

* [Important] 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)

* [Important] CVE-2017-5753 triggers the speculative execution by performing a bounds-check bypass. 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 boundary and read privileged memory by conducting targeted cache side-channel attacks. (CVE-2017-5753)

* [Important] CVE-2017-5754 relies on the fact that, on impacted microprocessors, during speculative execution of instruction permission faults, exception generation triggered by a faulting access is suppressed until the retirement of the whole instruction block. In a combination with the fact that memory accesses may populate the cache even when the block is being dropped and never committed (executed), an unprivileged local attacker could use this flaw to read privileged (kernel space) memory by conducting targeted cache side-channel attacks. (CVE-2017-5754)

This update also includes:

* criu 3.4.0.25.51-1.vz7
* qemu-kvm 2.9.0-16.3.vz7.36.3
* libvirt 3.6.0-1.vz7.17.2	

and its derivatives.

https://download.openvz.org/virtuozzo/releases/openvz-7.0.6-509/
https://download.openvz.org/virtuozzo/releases/7.0/x86_64/os/repoview/

See also
========

https://help.virtuozzo.com/customer/portal/articles/2914297
https://access.redhat.com/errata/RHSA-2018:0007
https://access.redhat.com/errata/RHSA-2018:0023
https://access.redhat.com/errata/RHSA-2018:0029
https://www.redhat.com/security/data/cve/CVE-2017-5715.html
https://www.redhat.com/security/data/cve/CVE-2017-5753.html
https://www.redhat.com/security/data/cve/CVE-2017-5754.html


Bug reporting
=============
Use http://bugs.openvz.org/ to report any bugs found.

Regards,
    OpenVZ team