On Mon 2017-09-25 09:33:42, Ingo Molnar wrote: > > * Pavel Machek <pa...@ucw.cz> wrote: > > > > For example, there would be collision with regular user-space mappings, > > > right? > > > Can local unprivileged users use mmap(MAP_FIXED) probing to figure out > > > where > > > the kernel lives? > > > > Local unpriviledged users can probably get your secret bits using cache > > probing > > and jump prediction buffers. > > > > Yes, you don't want to leak the information using mmap(MAP_FIXED), but CPU > > will > > leak it for you, anyway. > > Depends on the CPU I think, and CPU vendors are busy trying to mitigate this > angle.
I believe any x86 CPU running Linux will leak it. And with CPU vendors
putting "artifical inteligence" into branch prediction, no, I don't
think it is going to get better.
That does not mean we shoudl not prevent mmap() info leak, but...
Pavel
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