Messages in this thread | | | Date | Fri, 1 Feb 2002 14:22:10 -0600 | From | Ken Brownfield <> | Subject | Re: Continuing /dev/random problems with 2.4 |
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On Fri, Feb 01, 2002 at 12:57:03PM -0700, Andreas Dilger wrote: | Hmm, you may also need to delete /dev/urandom too. Reading from | /dev/urandom will also deplete the entropy pool just as much as | reading from /dev/random. The only difference is that /dev/random | will block if there aren't enough bits as requested, while reads | from /dev/urandom will happily continue to return data which isn't | "backed" by any entropy.
*forehead smack* Very good point.
| You could also enable debugging in drivers/char/random.c to see what | is going on (it may be very verbose). You could even change the one | message in extract_entropy() to include the command name, like: | | DEBUG_ENT("%s has %d bits, %s wants %d bits\n", | r == sec_random_state ? "secondary" : | r == random_state ? "primary" : "unknown", | current->comm, r->entropy_bits, nbytes * 8); | | (not sure of exact usage for current->comm, but you could use ->pid | instead).
I'll add this and see what pops up, thanks!
| Note that even traffic over the network will deplete your entropy | pool, because it is using secure_tcp_sequence_number() and secure_ip_id(). | Also, using SYN cookies appears to increase the amount of entropy used.
Very good to know. The machines that this has happened on don't all have tcp_syncookies enabled, and some have very little network traffic, so at first glance those don't seem to be involved.
Thanks, -- Ken. brownfld@irridia.com
| | Cheers, Andreas | -- | Andreas Dilger | http://sourceforge.net/projects/ext2resize/ | http://www-mddsp.enel.ucalgary.ca/People/adilger/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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