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Re: “Meltdown” and “Spectre”: Every modern processor has unfixable security flaws

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On Fri, Jan 05, 2018 at 10:33:45AM -0600, Nicholas Geovanis wrote:
> On Fri, Jan 5, 2018 at 6:55 AM,  <tomas@tuxteam.de> wrote:
> > (mainframes of that time had at least VM, possibly
> > speculative prefetch).
> 
> Is it correct to call branch prediction the same as speculative execution?

I'm far from a processor expert myself but yes, that sounds plausible: the
memory unit is prefeching stuff on the speculation that the branch will
go one way, to keep the pipeline full. When things go the other way...

> If so, then "yes" they had it, but I don't honestly know if that's correct.
> Pipeline rewinding was necessary on prediction failure, etc, similarly.

... this happens.

I guess that this, in combination with a cache, could be enough for the
kind of timing attacks demonstrated by Spectre. But I'm speculating myself
here :)

Cheers
- -- tomás
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“Meltdown” and  “Spectre”: Every modern processor has  unfixable security flaws Curt <curty@free.fr> - 2018-01-04 18:30 +0100
  Re: “Meltdown” and “Spectre”: Every modern processor has unfixable security flaws The Wanderer <wanderer@fastmail.fm> - 2018-01-04 18:40 +0100
  Re: “Meltdown” and “Spectre”: Every modern processor has unfixable security flaws Michael Fothergill <michael.fothergill@gmail.com> - 2018-01-04 18:50 +0100
    Re: “Meltdown” and “Spectre”: Every modern processor has unfixable security flaws The Wanderer <wanderer@fastmail.fm> - 2018-01-04 19:00 +0100
      Re: “Meltdown” and  “Spectre”: Every modern processor has  unfixable security flaws Tixy <tixy@yxit.co.uk> - 2018-01-04 19:20 +0100
        Re: “Meltdown” and “Spectre”: Every modern processor has unfixable security flaws The Wanderer <wanderer@fastmail.fm> - 2018-01-04 19:30 +0100
      Re: “Meltdown” and “Spectre”: Every modern processor has unfixable security flaws Michael Fothergill <michael.fothergill@gmail.com> - 2018-01-04 19:40 +0100
        Re: “Meltdown” and “Spectre”: Every modern processor has unfixable security flaws Nicholas Geovanis <nickgeovanis@gmail.com> - 2018-01-04 20:00 +0100
      Re: “Meltdown” and “Spectre”: Every modern processor has unfixable security flaws Jack Dangler <tdldev@gmail.com> - 2018-01-05 13:50 +0100
        Re: “Meltdown” and “Spectre”: Every modern processor has  unfixable security flaws <tomas@tuxteam.de> - 2018-01-05 14:00 +0100
          Re: "Meltdown" and "Spectre": Every modern processor has unfixable security flaws "Thomas Schmitt" <scdbackup@gmx.net> - 2018-01-05 14:50 +0100
            Re: "Meltdown" and "Spectre": Every modern processor has unfixable  security flaws <tomas@tuxteam.de> - 2018-01-05 15:40 +0100
              Re: "Meltdown" and "Spectre": Every modern processor has unfixable security flaws "Thomas Schmitt" <scdbackup@gmx.net> - 2018-01-05 16:50 +0100
                Re: "Meltdown" and "Spectre": Every modern processor has unfixable  security flaws <tomas@tuxteam.de> - 2018-01-05 17:10 +0100
                [OFFTOPIC] Re: "Meltdown" and "Spectre": Every modern processor has unfixable security flaws Stefan Monnier <monnier@iro.umontreal.ca> - 2018-01-05 19:10 +0100
                Re: [OFFTOPIC] Re: "Meltdown" and "Spectre": Every modern processor  has unfixable security flaws SDA <marathon.durandal@gmail.com> - 2018-01-08 02:40 +0100
                Re: [OFFTOPIC] Re: "Meltdown" and "Spectre": Every modern processor  has unfixable security flaws Curt <curty@free.fr> - 2018-01-08 11:30 +0100
                Re: [OFFTOPIC] Re: "Meltdown" and "Spectre": Every modern processor  has unfixable security flaws Tom Furie <tom@furie.org.uk> - 2018-01-08 13:10 +0100
          Re: “Meltdown” and “Spectre”: Every modern processor has unfixable security flaws Nicholas Geovanis <nickgeovanis@gmail.com> - 2018-01-05 17:40 +0100
            Re: “Meltdown” and “Spectre”: Every modern processor has  unfixable security flaws <tomas@tuxteam.de> - 2018-01-05 17:50 +0100
            [OFFTOPIC] Re: “Meltdown” and  “Spectre”: Every modern processor has unfixable  security flaws Stefan Monnier <monnier@iro.umontreal.ca> - 2018-01-05 19:10 +0100
  Re: “Meltdown” and “Spectre”: Every modern processor has unfixable security flaws francis picabia <fpicabia@gmail.com> - 2018-01-04 19:10 +0100
    Re: “Meltdown” and “Spectre”: Every modern processor has unfixable security flaws bw <bwtnguy@yahoo.com> - 2018-01-04 19:20 +0100
    Re: “Meltdown” and “Spectre”: Every modern processor has unfixable security flaws The Wanderer <wanderer@fastmail.fm> - 2018-01-04 19:20 +0100

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