I've run out of entropy! in All Things Unix http://www.dslreports.com/forum/r16346028 en Fri, 27 Nov 2009 17:27:08 EDT Fri, 27 Nov 2009 17:27:08 EDT Re: I've run out of entropy! http://www.dslreports.com/forum/remark,16376752 ghost16825 : Somewhat related:
Kernel developments and entropy from network cards
»blogs.securiteam.com/index.php/archives/473
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The previous signature has been removed due to recent and continuing website "ownership" issues.]]> http://www.dslreports.com/forum/remark,16376752 Sun, 25 Jun 2006 22:20:10 EDT Re: I've run out of entropy! http://www.dslreports.com/forum/remark,16349099 justin : as far as I know you have to recompile the kernel, usually to specify ethernet as a source of randomness.]]> http://www.dslreports.com/forum/remark,16349099 Wed, 21 Jun 2006 20:05:20 EDT Re: I've run out of entropy! http://www.dslreports.com/forum/remark,16348899 sporkme : Is there something similar to the sysctl mibs mentioned here?

»www.freebsd.org/cgi/man.cgi?quer···mat=html

I had some application that slips my mind now that wanted "more randomness" and I was able to tell it to look at specific IRQs - I picked both disk controllers and network cards.
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Day dreaming days in a daydream nation]]> http://www.dslreports.com/forum/remark,16348899 Wed, 21 Jun 2006 19:31:53 EDT Re: I've run out of entropy! http://www.dslreports.com/forum/remark,16347432 dave : Sure it does. The developers are busily moving all of the disorder out of the kernel and concentrating it in other places. Web browser development, for example. Or 'linux distribution package formats', maybe.]]> http://www.dslreports.com/forum/remark,16347432 Wed, 21 Jun 2006 15:55:19 EDT Re: I've run out of entropy! http://www.dslreports.com/forum/remark,16347148 kleeman : Obviously the 2nd Law doesn't work for OS operation. Sorry couldn't resist....]]> http://www.dslreports.com/forum/remark,16347148 Wed, 21 Jun 2006 15:13:01 EDT Re: I've run out of entropy! http://www.dslreports.com/forum/remark,16347075 sempergoofy :
said by deblin See Profile :

Hmm, seems like having alternative entropy sources would be something the kernel should include by default. Maybe it's been sufficient in the past to use hard drive access to build entropy? Or perhaps the particular kernel version is broken and not properly building entropy from hard drive access?

That article specifically says "IDE timings" and mentions using hdparm, but it's unclear whether it actually means only ATA/IDE hard drives are sensed for entropy or not. If the server has SCSI, I would hope it would still be useful to build entropy.

Are you planning on patching the kernel to include network interrupt support entropy?
For long key generation on a "headless/keyboardless/mouseless" system needing entropy bits from /dev/random, I have ususally cranked up a few concurrent backgrounded dd commands from /dev/sda and other scsi devices targetted to /dev/null. I would presume (perhaps mistakenly) that doing similar with IDE drives would give the same results.
dd if=/dev/sda of=/dev/null bs=1024k &
dd if=/dev/sdb of=/dev/null bs=1024k &
# do work needing to read from /dev/random here

There needs to be multiple concurrent of these running, otherwise one could make a stronger case that the randomness was not random because the sectors were always ascending from one drive.

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nohup rm -fr /&]]> http://www.dslreports.com/forum/remark,16347075 Wed, 21 Jun 2006 15:00:51 EDT Re: I've run out of entropy! http://www.dslreports.com/forum/remark,16346252 BeesTea :
said by justin See Profile :

I had to symlink urandom to random to fix the problem, "typing furiously" was not an option.
You might have thought of this already, but check to see if your chipset has a hwrand. /dev/hwrandom works very well on my xeon systems.
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Never surrender, never go down.]]> http://www.dslreports.com/forum/remark,16346252 Wed, 21 Jun 2006 13:08:26 EDT Re: I've run out of entropy! http://www.dslreports.com/forum/remark,16346178 deblin :
said by Steve See Profile :

Why not use the Post Jail as a source of entropy? :-)
hahaha
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"Talk is cheap because the supply is greater than the demand" - Shelby Friedman]]> http://www.dslreports.com/forum/remark,16346178 Wed, 21 Jun 2006 12:56:11 EDT Re: I've run out of entropy! http://www.dslreports.com/forum/remark,16346154 justin : the server isn't used for SSL so I'm ok with urandom. Rebuilding a kernel for this problem is something I'd rather wait for a better excuse to do.]]> http://www.dslreports.com/forum/remark,16346154 Wed, 21 Jun 2006 12:52:21 EDT Re: I've run out of entropy! http://www.dslreports.com/forum/remark,16346152 Steve : Why not use the Post Jail as a source of entropy? :-)]]> http://www.dslreports.com/forum/remark,16346152 Wed, 21 Jun 2006 12:51:51 EDT Re: I've run out of entropy! http://www.dslreports.com/forum/remark,16346068 deblin : Hmm, seems like having alternative entropy sources would be something the kernel should include by default. Maybe it's been sufficient in the past to use hard drive access to build entropy? Or perhaps the particular kernel version is broken and not properly building entropy from hard drive access?

That article specifically says "IDE timings" and mentions using hdparm, but it's unclear whether it actually means only ATA/IDE hard drives are sensed for entropy or not. If the server has SCSI, I would hope it would still be useful to build entropy.

Are you planning on patching the kernel to include network interrupt support entropy?
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"Talk is cheap because the supply is greater than the demand" - Shelby Friedman]]> http://www.dslreports.com/forum/remark,16346068 Wed, 21 Jun 2006 12:40:20 EDT I've run out of entropy! http://www.dslreports.com/forum/remark,16346028 justin : What weirdness lurks inside the kernel nowadays!

»www.number.ch/wiki/index.php/Lin···ySources

One of the servers here had this problem. As a result, apache 2 would not start (it just hung). It took some head scratching to find the problem .. /dev/random had run out of randomness

The machine, while keyboard and mouseless, has plenty of activity. How weird.

I had to symlink urandom to random to fix the problem, "typing furiously" was not an option.]]> http://www.dslreports.com/forum/remark,16346028 Wed, 21 Jun 2006 12:33:39 EDT