Gentoo Websites Logo
Go to: Gentoo Home Documentation Forums Lists Bugs Planet Store Wiki Get Gentoo!
Bug 643342 (CVE-2017-5715) - [TRACKER] hw: cpu: speculative execution branch target injection (CVE-2017-5715)
Summary: [TRACKER] hw: cpu: speculative execution branch target injection (CVE-2017-5715)
Alias: CVE-2017-5715
Product: Gentoo Security
Classification: Unclassified
Component: Vulnerabilities (show other bugs)
Hardware: All Linux
: Normal normal (vote)
Assignee: Gentoo Security
Keywords: Tracker
Depends on: 646758 XSA-254 643352 643430 643432 643476 643764 643794 643808 644128 CVE-2018-5091, MFSA-2018-03
Blocks: 643228
  Show dependency tree
Reported: 2018-01-04 01:02 UTC by GLSAMaker/CVETool Bot
Modified: 2024-03-03 21:59 UTC (History)
10 users (show)

See Also:
Package list:
Runtime testing required: ---


Note You need to log in before you can comment on or make changes to this bug.
Description GLSAMaker/CVETool Bot gentoo-dev 2018-01-04 01:02:22 UTC
Incoming details.
Comment 1 Thomas Deutschmann (RETIRED) gentoo-dev 2018-01-04 01:11:04 UTC
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.


External References:
Comment 2 Thomas Deutschmann (RETIRED) gentoo-dev 2018-01-04 01:22:00 UTC
Converting into tracker bug, needed for Xen as well.
Comment 3 kfm 2018-02-07 04:11:00 UTC
Just linking a post by David Woodhouse here, as is greatly clarifies the various mitigation techiques that have been devised. An important aspect of the present situation is that retpolines, alone, constitute a viable mitigation technique for CVE-2017-5715 - but not wholly so if using Skylake or newer.