Re: Meltdown and spectre

Some UEK4 patches have just appeared that weren't there yesterday. I've not checked the contents, but it would be rather coincidental if they weren't related to this. :)

On Fri, Jan 5, 2018 at 11:51 PM, Hans Forbrich <fuzzy.graybeard_at_gmail.com> wrote:

> On 2018-01-05 2:33 PM, Reen, Elizabeth (Redacted sender elizabeth.reen for
> DMARC) wrote:
>
> I have a background in system engineering. I don’t get how a chip can be
> exploited. What code can be hacked there?
>
> For speculative execution, a command is executed that MIGHT be required.
> That command might ask to move stuff into some portion of memory, or need a
> specific page moved in. If that command is then rolled back, what happens
> to the memory that it just filled? (Hint: it's still filled in, perhaps
> with a password.) Back in the day (early 90s) when this stuff was dreamt
> up, the idea of flushing that memory on command rollback would not have
> been a concern - hacking was for fun, not profit, in those days. It's not
> actually the code being hacked, as much as a side effect that is not
> properly handled.
>
> It wasn't just the hardware guys, either. We s/w devs were pretty sloppy
> about things like end-of-arrays and random pointers in our code, and few
> people worried about (or even understood) what happened at the chip level.
> (Remember why Java came into being?)
>
> /Hans
>

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