What security issue? [LWN.net]

What security issue?

Posted Dec 4, 2008 3:12 UTC (Thu) by mjg59 (subscriber, #23239)
In reply to: What security issue? by NCunningham
Parent article: KSM runs into patent trouble

Anything could run, but it's possible that nothing will. And that means that a sufficient number of repetitions may show a significant deviation from what you'd expect from chance alone, which is an information leak.

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What security issue?

Posted Dec 5, 2008 0:11 UTC (Fri) by nix (subscriber, #2304) [Link]

TBH preventing information leaks on any single system is a hopeless task:
there are far too many potential avenues, and when you get right down to
it they *are* one single system, so one process consuming a shareable
resource will always be observable by another process attempting to get
access to the same resource. (Crude example: time. Busywait, watching the
time: if it skips, you know someone else is using the same core.)

If you want to avoid information leaks, run the high-sensitivity no-leak
stuff on a different physical machine. Nothing else is safe enough for the
paranoid, and only the paranoid will really care about this anyway.