[onerng talk] Redirect output to urandom and link random to urandom

[Paul Campbell]

On Friday, 27 May 2016 9:50:20 AM NZST alexandre wrote:
> I was milead i think by the led on the onerng then. when i launch the
> classic onerng.sh script  on default /dev/random  and then i test with cat
> /dev/urandom > /dev/null ; the led stay bright. 

The LED stays bright because of the change mentioned above, more modern 
kernels restrict /dev/urandom's dipping into the shared pool to once every 60 
seconds (by default) - looking at the code I think the idea wass to stop /dev/
random being stalled by lots of /dev/urandom traffic - with all our extra 
entropy available we can avoid that and can set the urandom parameter to 
inject as much entropy as possible into it

(My day job involves working with embedded linux systems, my go to kernel 
source is old enough that it doesn't have this mechanism)

> However when launching rngd -o /dev/urandom ; then the leds is always dim. I
> tought this was the result of all the programs (lsof | grep urandom) that
> where using it .
> 
> Can you explain this behavior?

I'm not sure I can (unless you are reading from /dev/random and writing to /
dev/urandom or some such) - what kernel are you running? I'll have to look at 
that source and see what else might have changed


	Paul