Re: [RFC]: mm,power: introduce MADV_WIPEONSUSPEND

Hi!

quoted

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Cryptographic libraries carry pseudo random number generators to
quickly provide randomness when needed. If such a random pool gets
cloned, secrets may get revealed, as the same random number may get
used multiple times. For fork, this was fixed using the WIPEONFORK
madvise flag [1].

quoted

Unfortunately, the same problem surfaces when a virtual machine gets
cloned. The existing flag does not help there. This patch introduces a
new flag to automatically clear memory contents on VM suspend/resume,
which will allow random number generators to reseed when virtual
machines get cloned.

Umm. If this is real problem, should kernel provide such rng in the
vsdo page using vsyscalls? Kernel can have special interface to its
vsyscalls, but we may not want to offer this functionality to rest of
userland...

And then the kernel would just need to maintain a sequence
number in the vDSO data page that gets bumped on suspen

Yes, something like that would work. Plus, we'd be free to change the
mechanism in future.

Best regards,
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
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