On 2018-01-05 09:15, DaveFroble wrote:
Jan-Erik Soderholm wrote:

Becuse the designers, for performance reasons, has mapped kernel memory
into the user process address space and relies on the OS to check
protection before any kernel memory (or code) is accessed.

The issue with the current issues is that the hardware (the CPU) does
these accesses in hardware "under the hood" without control by the OS.

If you map your kernel memory in another way that uses the hardware
protection facilities, you are (as I understand) safe, at the cost
of worse performance to switch between user and kernel mode.



As I wrote, someone dropped the ball on this one.

Speculative execution is part of the HW, not software.Â* It appears the
HW doesn't follow it's own rules.Â* Or, perhaps I don't actually
understand the problem?

At least as well as I do. These are very complex mechanisms and
complexity is usually where you're most likely to get problems.

In this case the h/w implementation didn't reflect the design goal.

This means intel had very poor design review and abysmal testing of
security features.

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