From: mark gross <mgross@linux.intel.com>
To: speck@linutronix.de
Subject: [MODERATED] Re: [PATCH 0/2] more sampling fun 0
Date: Thu, 20 Feb 2020 07:40:07 -0800 [thread overview]
Message-ID: <20200220154007.GC58564@mtg-dev.jf.intel.com> (raw)
In-Reply-To: <20200220142720.GA3433900@kroah.com>
On Thu, Feb 20, 2020 at 03:27:20PM +0100, speck for Greg KH wrote:
> On Thu, Feb 20, 2020 at 09:14:20AM +0100, speck for Greg KH wrote:
> > On Wed, Feb 19, 2020 at 02:45:22PM -0800, speck for mark gross wrote:
> > > From: mark gross <mgross@linux.intel.com>
> > > Subject: [PATCH 0/2] Special Register Buffer Data Sampling patch set
> > >
> > > Special Register Buffer Data Sampling is a sampling type of vulnerability that
> > > leaks data across cores sharing the HW-RNG for vulnerable processors.
> > >
> > > This leak is fixed by a microcode update and is enabled by default.
> > >
> > > This new microcode serializes processor access during execution of RDRAND
> > > or RDSEED. It ensures that the shared buffer is overwritten before it
> > > is released for reuse.
> > >
> > > The mitigation impacts the throughput of the RDRAND and RDSEED instructions
> > > and latency of RT processing running on the socket while executing RDRAND or
> > > RDSEED. The micro bechmark of calling RDRAND many times shows a 10x slowdown.
> >
> > Then we need to stop using RDRAND internally for our "give me a random
> > number api" which has spread to more and more parts of the kernel.
> >
> > Here's a patch that does so:
> > https://lore.kernel.org/lkml/20200216161836.1976-1-Jason@zx2c4.com/
> > which I'm going to advise get merged now and backported to the stable
> > branches.
>
> Note, the author of that patch has reached out to me to say they found
> this same issue. He did so independantly so odds are others already
> know about this. He found it because he was wondering why rdrand was so
> slow on newer systems, and then traced things backwards like all the
> other researchers in this area.
Are you saying the author has seen the RNG data leaking across processors or
the slowdown?
>
> So, what's the timeline here? Looks like this is already "in the wild"
> from what I can tell.
>
The uCode mitigation is coming out with the 2020.1 IPU (intel platform update)
(fist ucode update of 2020) that I belive is slated for an official May
disclosure.
--mark
> greg k-h
next prev parent reply other threads:[~2020-02-20 15:40 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-19 22:45 [MODERATED] [PATCH 0/2] more sampling fun 0 mark gross
2020-02-20 1:53 ` [MODERATED] " mark gross
2020-02-20 8:14 ` Greg KH
2020-02-20 14:27 ` Greg KH
2020-02-20 15:40 ` mark gross [this message]
2020-02-20 16:18 ` Greg KH
2020-02-20 14:55 ` Andi Kleen
2020-02-20 15:05 ` Greg KH
2020-02-20 16:55 ` Andi Kleen
2020-02-20 21:51 ` Josh Poimboeuf
2020-02-20 22:15 ` Andi Kleen
2020-02-20 22:59 ` Kees Cook
2020-02-20 15:09 ` mark gross
2020-02-28 16:21 ` [MODERATED] Additional sampling fun Borislav Petkov
2020-02-28 16:34 ` [MODERATED] " Greg KH
2020-02-28 17:38 ` mark gross
2020-02-28 17:44 ` Thomas Gleixner
2020-02-28 18:09 ` [MODERATED] " Luck, Tony
2020-02-28 18:40 ` Borislav Petkov
2020-02-28 21:53 ` Thomas Gleixner
2020-03-03 1:03 ` [MODERATED] " Luck, Tony
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