Intel Fail: OpenBSD disables Intel HyperThreading, Lazy FP State Restore

Zenaan Harkness zen at
Mon Jun 25 18:58:03 PDT 2018

On Mon, Jun 25, 2018 at 05:22:11PM +0300, Georgi Guninski wrote:
> On Wed, Jun 20, 2018 at 07:44:21PM -0400, grarpamp wrote:
> >
> According to journos intel won't fix this:
> Meet TLBleed: A crypto-key-leaking CPU attack that Intel reckons we
> shouldn't worry about
> How to extract 256-bit signing keys with 99.8% success
> Intel has, for now, no plans to specifically address a side-channel
> vulnerability in its processors that can be potentially exploited by
> malware to extract encryption keys and other sensitive info from
> applications.

Surely a simple and far less impactful "solution" to this problem is
for applications to disable hyperthreading when they enter the
critical sections of code - generating (and using?) crypto keys and
random numbers for example?

OpenBSD is understandable of course - "security or die" - but perhaps
they will relax their HT disabling over time as they sure app the HT
barrier code required to implement the aboveā€¦

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