freebsd security - Jan 2018 - Intel hardware bug

In message <736a2b77-d4a0-b03f-8a6b-6a717f5744d4 at metricspace.net>, 
Eric McCorkle <eric at metricspace.net> wrote:
>The attack looks like this:
>
>1) Fetch kernel/other process memory, which eventually faults
>2) Do a bit-shift/mask operation to pluck out one bit of the fetched
>value.  This gets executed speculatively on the fetched value in (1).
>3) Execute fetches of two different addresses depending on some bit in
>the fetched value in (1) (say, 0x100000 for 0 vs 0x200000 for 1).  This
>also gets executed speculatively despite the fact that (1) ends up faulting.
>4) Recover from fault in (1)
>5) Measure performance of accesses to the two addresses to determine
>which one is cached.

I must say, that's one hell of a round-about way to read just one bit that
you wern't supposed to have access to.  But of course, that doesn't
really
matter if you are an attacker.

If the above steps can be repeated, programatically, ad infinitum, to read
bits from "protected" memory... and I see no reason why they can't
be...
then yea, this bug is every bit as bad as the media is making it out to be,
and maybe even worse.

All your secrets are belong to us!

Time to invest in abacuses... or is that abacai?


Regards,
rfg

Sorry guys, you just convinced me that no one, not the NSA, not the FSB, no
one!, has in the past, or will in the future be able to exploit this to actually
do something not nice.
I'm not saying that the hardware shouldn't be fixed, I am saying that we
don't need to worry about this.
In the early days of DOS their was a hardware bug in nearly all floppy
controllers, it wasn't even discovered until (I think,) 1985 or so.? The
thing is..., no one reported unusual problems.
So what is this, really?, it's a market exploit opportunity for AMD.

 

    On Friday, January 5, 2018, 3:33:31 AM EST, Ronald F. Guilmette <rfg at
tristatelogic.com> wrote:
 
 
In message <736a2b77-d4a0-b03f-8a6b-6a717f5744d4 at metricspace.net>, 
Eric McCorkle <eric at metricspace.net> wrote:
>The attack looks like this:
>
>1) Fetch kernel/other process memory, which eventually faults
>2) Do a bit-shift/mask operation to pluck out one bit of the fetched
>value.? This gets executed speculatively on the fetched value in (1).
>3) Execute fetches of two different addresses depending on some bit in
>the fetched value in (1) (say, 0x100000 for 0 vs 0x200000 for 1).? This
>also gets executed speculatively despite the fact that (1) ends up faulting.
>4) Recover from fault in (1)
>5) Measure performance of accesses to the two addresses to determine
>which one is cached.

I must say, that's one hell of a round-about way to read just one bit that
you wern't supposed to have access to.? But of course, that doesn't
really
matter if you are an attacker.

If the above steps can be repeated, programatically, ad infinitum, to read
bits from "protected" memory... and I see no reason why they can't
be...
then yea, this bug is every bit as bad as the media is making it out to be,
and maybe even worse.

All your secrets are belong to us!

Time to invest in abacuses... or is that abacai?


Regards,
rfg
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