Re: [PATCH] (0/4) Entropy accounting fixes

From: Linus Torvalds (
Date: Sat Aug 17 2002 - 22:25:55 EST

Hmm.. After more reading, it looks like (if I understood correctly), that
since network activity isn't considered trusted -at-all-, your average
router / firewall / xxx box will not _ever_ get any output from
/dev/random what-so-ever. Quite regardless of the context switch issue,
since that only triggers for trusted sources. So it was even more
draconian than I expected.

Are you seriously trying to say that a TSC running at a gigahertz cannot
be considered to contain any random information just because you think you
can time the network activity so well from the outside?

Oliver, I really think this patch (which otherwise looks perfectly fine)
is just unrealistic. There are _real_ reasons why a firewall box (ie one
that probably comes with a flash memory disk, and runs a small web-server
for configuration) would want to have strong random numbers (exactly for
things like generating host keys when asked to by the sysadmin), yet you
seem to say that such a user would have to use /dev/urandom.

If I read the patch correctly, you give such a box _zero_ "trusted"
sources of randomness, and thus zero bits of information in /dev/random.
It obviously won't have a keyboard or anything like that.

This is ludicrous.


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This archive was generated by hypermail 2b29 : Fri Aug 23 2002 - 22:00:14 EST