/dev/random vs. /dev/urandom and the krb5 test suite
Tom Yu
tlyu at MIT.EDU
Mon Jun 22 17:03:45 EDT 2009
Sam Hartman <hartmans at MIT.EDU> writes:
>>>>>> "Greg" == Greg Hudson <ghudson at MIT.EDU> writes:
>
> Greg> * There isn't much operational reason why you'd want to
> Greg> suppress the use of /dev/random in favor of /dev/urandom for
> Greg> all keys. There was one report (from iastate) of a case
> Greg> where a server was so random-starved as to be unable to
> Greg> start kadmind, but using /dev/urandom in that case would be
> Greg> dangerous because the amount of entropy present might be so
> Greg> low as to be attackable. So we are talking purely about an
> Greg> option to be used to make the test suite friendlier to hosts
> Greg> with limited amounts of /dev/random entropy.
>
>
> It turns out we've seen this in a number of cases in Debian. It's
> generally acceptable to hold off starting up kadmind until the entropy
> pool fills. However it's generally not acceptable to Debian's users
> to block the system initialization process until that happens.
>
> The problem was fixed by seeding the PRNG from /dev/random after
> kadmind forks. I believe that was pushed upstream.
Do you recall the Debian or krbdev RT bug numbers?
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