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Subject: Re: clang way to patch for Spectre?
To: freebsd-security@freebsd.org
References: <291645341.20180104190237@serebryakov.spb.ru>
 <43417734-d420-5be9-333b-8d0d02d7a58a@freebsd.org>
From: =?UTF-8?Q?Karsten_K=c3=b6nig?= <mail@kkoenig.net>
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Date: Thu, 4 Jan 2018 19:18:05 +0100
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Hi,

On 01/04/2018 18:49, Julian Elischer wrote:
> On 5/1/18 12:02 am, Lev Serebryakov wrote:
>> Hello Freebsd-security,
>>
>> https://reviews.llvm.org/D41723
>>
>>
> not really..
> 
> What's to stop an unprivileged used bringing his own compiler? or a
> precompiled binary?
>

>From my understanding: The patch is only for variant 2 of the Google P0
blog post[0]. Variant 2 describes how to access memory of a VM host from
a guest by tricking kernel modules into caching arbitary inside the CPU
cache. But if these are compiled with the patch[1] an attacker can't
trick the kernel modules or other applications compiled with it.

Best,

Karsten

[0]
https://googleprojectzero.blogspot.de/2018/01/reading-privileged-memory-with-side.html
[1] Which I assume to be correct, I haven't looked into it