There was some interest in this expressed on the hardened mailing list. One area that might need review is the init dependencies; I don't know whether or not it's possible to hot/cold/whatever plug the timer source so I'm doing, after bootmisc modules isapnp coldplug hotplug which may or may not make sense.
Created attachment 222779 [details] Working ebuild.
Created attachment 222781 [details] Init script for timer_entropyd.
Vote for early inclusion from me... With SSP enabled the entropy pool is basically zapped to double/triple digits in seconds and on a headless webserver (trying not to touch disk) it's basically not generating much entropy of it's own. I have tried all the other "entropy demons" currently in portage and none are appropriate except clrngd and that thing chewed 100% CPU for 90 seconds out of every 4 minutes and only generated a negligible amount of entropy.
I just added this to the Sunrise overlay. Once reviewed by a developer, it will find its way to, http://overlays.gentoo.org/proj/sunrise/browser/reviewed/sys-apps/timer_entropyd
A bit late to close, but this has been in tree for a while ^^ Thanks Michael for letting me know there was a bug :P
