Re: Lightweight support for instruction RNGs

Taylor R Campbell <[email protected]> Sun, 20 Dec 2015 22:34:29 +0000

Newsgroups	gmane.os.netbsd.ports.x86-64,gmane.os.netbsd.devel.kernel,gmane.os.netbsd.devel.crypto,gmane.os.netbsd.ports.i386,gmane.os.netbsd.devel.security
Message-ID	<[email protected]>

   Date: Sat, 19 Dec 2015 19:37:22 -0500
   From: Thor Lancelot Simon <[email protected]>

   I was playing with code for a RDRAND/RDSEED entropy source and it
   just felt like -- much like opencrypto is poorly suited for crypto
   via unprivileged CPU instructions -- our rndsource interface is
   a little too heavy for CPU RNGs implemented as instructions.

Why is it a little too heavy?  How does the cpu_rng abstraction
improve it?

I'm very leery of adding more mechanism to an already unbelievably
complicated entropy pool system, and particularly of a special
mechanism for RDRAND/RDSEED.

I think we'd be better off simplifying what we have than adding new
bells and whistles.