I am running LMS (squeezebox) on my readynas ultra. There is a problem with the Random mix. The problem is that it isn't very random.The problem could be this that I have read about:http://www.issihosts.com/haveged/Is it possible to get Haveged to run on a ReadyNas. And if. How ?If this really is a problem in the kernel software. Will this not be fixed ????

Callesoroe wrote:I am running LMS (squeezebox) on my readynas ultra. There is a problem with the Random mix. The problem is that it isn't very random.The problem could be this that I have read about:http://www.issihosts.com/haveged/I thought that that was unlikely, and I was about to post a response saying so... But then I checked my Pro Pioneer's available entropy and discovered that it was REALLY low -- single digits or low double digits -- and I took those measurements while I was logged in and right after I'd performed some filesystem commands that should have produced a large increase in available entropy.Maybe there's something on my system that is voraciously consuming entropy; I'll have to investigate further. But I guess it is possible that an additional entropy source like havege could be helpful.

Tested on an Ultra 4 running RAIDiator-x86 4.2.23:# cat /proc/sys/kernel/random/entropy_avail 221# cat /proc/sys/kernel/random/entropy_avail 131# wget http://http.us.debian.org/debian/pool/main/h/haveged/haveged_1.4-4_i386.deb# dpkg -i haveged_1.4-4_i386.deb Setting up haveged (1.4-4) ...# cat /proc/sys/kernel/random/entropy_avail 3968# cat /proc/sys/kernel/random/entropy_avail 3712

Tested on Ultra 4 running ReadyNAS OS 6.1.3:# cat /proc/sys/kernel/random/entropy_avail 203# cat /proc/sys/kernel/random/entropy_avail 134# wget http://http.us.debian.org/debian/pool/main/h/haveged/haveged_1.4-4_amd64.deb# dpkg -i haveged_1.4-4_amd64.deb Setting up haveged (1.4-4) ...[ ok ] Starting haveged (via systemctl): haveged.service.# cat /proc/sys/kernel/random/entropy_avail 2339# cat /proc/sys/kernel/random/entropy_avail 2211

chirpa wrote:# cat /proc/sys/kernel/random/entropy_avail 203# cat /proc/sys/kernel/random/entropy_avail 134On my Pro Pioneer running 4.2.24, after 7 hours of uptime, my first read was 3 and I never got a value above 120 bits even after lots of file-access-induced hardware randomness.Chirpa, I notice that even with haveged running, each of your "cat" invocations seemed to consume around 100 bits of entropy. If you do something like "watch cat /proc/sys/kernel/random/entropy_avail" with haveged running, does the available entropy stay high (or refill when it gets below the read threshold), or does it fall all the way to single digits as it would without haveged?

When it drops below 1024 (default), it refills back up to 4000.# cat /etc/default/haveged # Configuration file for haveged # Options to pass to haveged # -w sets low entropy watermark (in bits) DAEMON_ARGS="-w 1024"# while true; do cat /proc/sys/kernel/random/entropy_avail; sleep 1; done14081152384035843328307228162630237421181862160612481072396837123456^C

Haveged on ReadyNas Ultra ? | NETGEAR Communities

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F_L_
Tutor
Jan 03, 2014
StephenB wrote:
F.L. wrote:
Is this needed on OS6 6.1.5?
My RN102 reports values between 100-200 - similar to what fastfwd saw before he did the add-on.

Strange, now I have low values again.
And
watch -n 1 cat /proc/sys/kernel/random/entropy_avail
gives me low values too.
Wonder why I had high values before...

Anyway. I installed haveged using apt and now it seems OK again.
fastfwd
Virtuoso
Jan 03, 2014
F.L. wrote:
Strange, now I have low values again.
And
watch -n 1 cat /proc/sys/kernel/random/entropy_avail
gives me low values too.
Wonder why I had high values before...

If nothing is using dev/random or dev/urandom, the entropy pool gradually fills. Presumably, your system wasn't doing much that needed random numbers, so the pool filled to 2000+ bits.

Every time a new process is launched, the operating system reads from dev/urandom in order to randomize the process's address space layout (to protect from buffer overflow attacks), so when you repeatedly invoked cat once per second with that watch command, the available entropy decreased faster than it could be replenished.

F.L. wrote:
Strange, now I have low values again. And watch -n 1 cat /proc/sys/kernel/random/entropy_avail gives me low values too. Wonder why I had high values before...

F_L_

Tutor

Jan 03, 2014

fastfwd wrote:
F.L. wrote:
Strange, now I have low values again.
And
watch -n 1 cat /proc/sys/kernel/random/entropy_avail
gives me low values too.
Wonder why I had high values before...
If nothing is using dev/random or dev/urandom, the entropy pool gradually fills. Presumably, your system wasn't doing much that needed random numbers, so the pool filled to 2000+ bits.

Every time a new process is launched, the operating system reads from dev/urandom in order to randomize the process's address space layout (to protect from buffer overflow attacks), so when you repeatedly invoked cat once per second with that watch command, the available entropy decreased faster than it could be replenished.

Thank you fastfwd for the explanation!

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Haveged on ReadyNas Ultra ?

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