Date: Thu, 4 Jan 2018 19:51:12 +0100 From: =?UTF-8?Q?Jan_Kokem=c3=bcller?= <jan.kokemueller@gmail.com> To: "Klaus P. Ohrhallinger" <k@7he.at>, freebsd-current@freebsd.org Subject: Re: Intel CPU design flaw - FreeBSD affected? // disabling LDTSC Message-ID: <c675036c-f300-839a-930c-cbe1b4d1c580@gmail.com> In-Reply-To: <18376c97-3c0d-49c8-9483-96b95a84f3f1@7he.at> References: <9dda0496-be16-35c6-6c45-63d03b218ccb@protected-networks.net> <18376c97-3c0d-49c8-9483-96b95a84f3f1@7he.at>
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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/
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