Messages in this thread |  | | | Date | Tue, 8 Aug 2000 19:42:39 +0200 | | From | "Andi Kleen" <> | | Subject | Re: /dev/random blocks forever on 2.2.12 and 2.2.16 |
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On Tue, Aug 08, 2000 at 01:39:35PM -0400, Theodore Y. Ts'o wrote: > Date: Tue, 8 Aug 2000 16:04:13 +0200 > From: "Andi Kleen" <ak@suse.de> > > I'm not sure. One possible attack would be to try to change your > entropy pool by sending packets in the right frequency, also > e.g. regular broadcasts may not have enough jitter. One possible fix > for that would be to use a secure random generator with a secret that > selects which packets to get information from etc, but there may be > again attacks with that. > > Actually, that isn't the real disaster. The real worry here is if an > attacker can break into a machine on your local network and using > tcpdump, and then be able to guestimate what the inputs to your entropy > pool is based on the network interrupts. Given that the pentium cycle > counter is mixed in, this is actually pretty difficult, but it's really > matter of how paranoid you are.
That wouldn't happen when you were using a secure PRNG to select the interrupts to get data from, or ? You just have to make sure that the PRNG initial state is not seeded from the network or anything else the attacker could guess.
-Andi
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