[MODERATED] Re: [PATCH v2 3/8] MDSv2 5

[Linus Torvalds <torvalds@linux-foundation.org>]

Ok, re-sending again.

It looks like speck doesn't have my other cert, so when I send with
the cert I want to use it ends up never being decrypted (and then
re-encrypted with the speck cert) by the mailing list.

               Linus

On Tue, Dec 11, 2018 at 9:55 AM Linus Torvalds wrote:
>
> [ Let's see if this comes through legibly ]
>
> On Mon, Dec 10, 2018 at 7:27 PM speck for Andi Kleen wrote:
> >
> > > In fact, maybe we could have something like a TIF_SCRUBME thread flag,
> > > which we react to on return to user space, and on context switch.
> >
> > We'll have to disable interrupts in that window, but that
> > should be ok.
>
> I don't think we even need to disable interrupts.
>
> If an interrupt comes in while we're scrubbing, either that interrupt
> will touch sensitive data (and set TIF_SCRUBME) or it won't.
>
> If it *does* set TIF_SCRUBME, we'll just re-do the scrub, and if it
> *doesn't* touch sensitive data, we'll return to the scrubbing having
> touched even more cachelines so any old sensitive data should be fine.
>
> Yeah, yeah, it might affect some cache replacement logic that the SW
> scrubbing code might depend on in theory, but that's pretty damn
> theoretical. Good luck to anybody trying to attack that.
>
>                 Linus