Re: Intel CPU design flaw - FreeBSD affected? // disabling LDTSC

From: Jan Kokemüller <jan.kokemueller_at_gmail.com>
Date: Thu, 4 Jan 2018 19:51:12 +0100
On 04.01.2018 19:23, Klaus P. Ohrhallinger wrote:
> All PoC code I have seen today relies on those instructions.
> Is there any other way to measure the memory/cache access times ?

It is possible to emulate a high resolution counter with a thread that
continuously increments a variable [1]. This is the reason why browser
vendors are currently disabling the SharedArrayBuffer feature [2].

[1]: https://gist.github.com/ErikAugust/724d4a969fb2c6ae1bbd7b2a9e3d4bb6#gistcomment-2311156
[2]: https://blog.mozilla.org/security/2018/01/03/mitigations-landing-new-class-timing-attack/
Received on Thu Jan 04 2018 - 17:51:16 UTC

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