On Wednesday 09 March 2005 09:15 pm, Jeff Dike wrote: > This implements a hardware random number generator for UML which attaches > itself to the host's /dev/random.
Direct use of /dev/random always makes me nervous. I've had a recurring problem with /dev/random blocking, and generally configure as much as possible to use /dev/urandom instead. It's really easy for a normal user to drain the /dev/random entropy pool on a server (at least one that doesn't have a sound card you can tell it to read white noise from). cat /dev/random > /dev/null I like /dev/urandom because it'll feed you as much entropy as it's got, but won't block, and will presumably round-robin insert real entropy in the streams that multiple users get from /dev/urandom. (I realize this may not be the best place to get gpg keys from.) I'm just thinking about those UML hosting farms, with several UML instances per machine, on machines which haven't got a keyboard attached constantly feeding entropy into the pool. If just ONE of them is serving ssl connections from its own /dev/urandom, that would drain the /dev/random entropy pool on the host machine almost immediately... Admittedly if UML used /dev/urandom instead of /dev/random, it wouldn't know how much "real" randomness it was getting and how much synthetic randomness, but this makes predicting the numbers it's producing easier how? Rob - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
