On Fri, Oct 3, 2014 at 2:12 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Fri, Oct 03, 2014 at 02:04:53PM -0700, Andy Lutomirski wrote: >> On Fri, Oct 3, 2014 at 2:02 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > >> > Something like so.. slightly less ugly and possibly with more >> > complicated conditions setting the cr4 if you want to fix tsc vs seccomp >> > as well. >> >> This will crash anything that tries rdpmc in an allow-everything >> seccomp sandbox. It's also not very compatible with my grand scheme >> of allowing rdtsc to be turned off without breaking clock_gettime. :) > > Well, we clear cap_user_rdpmc, so everybody who still tries it gets what > he deserves, no problem there. Oh, interesting. To continue playing devil's advocate, what if you do perf_event_open, then mmap it, then start the seccomp sandbox? My draft patches are currently tracking the number of perf_event mmaps per mm. I'm not thrilled with it, but it's straightforward. And I still need to benchmark cr4 writes, which is tedious, because I can't do it from user code. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
