On Wed, 9 Jan 2019, Dave Chinner wrote: > > But mincore is certainly the easiest interface, and the one that > > doesn't require much effort or setup. > > Off the top of my head, here's a few vectors for reading the page > cache residency state without perturbing the page cache residency > pattern: > - mincore > - preadv2(RWF_NOWAIT) > - fadvise(POSIX_FADV_RANDOM); timed read(2) syscalls > - madvise(MADV_RANDOM); timed read of first byte in each page
While I obviously agree that all those are creating pagecache sidechannel in principle, I think we really should mostly focus on the first two (with mincore() already having been covered). Rationale has been provided by Daniel Gruss in this thread -- if the attacker is left with cache timing as the only available vector, he's going to be much more successful with mounting hardware cache timing attack anyway. Thanks, -- Jiri Kosina SUSE Labs
