svn commit: r317015 - in head/sys: boot/forth conf crypto/chacha20 dev/random libkern sys

[Rodney W. Grimes]

> 
> > On 16 Apr 2017, at 13:07, Rodney W. Grimes <freebsd at pdx.rh.CN85.dnsmgr.net> wrote:
> > 
> >>> From replacing the rc4 algorithm with chacha20, this chalice has now
> >> become poisoned with the job of redesigning the entire structure of
> >> kernel random-number generation.
> >> 
> >> This may take a while, and I'm already behind on RNG jobs.
> > 
> > I do not see how this is a complete redesign of RNG, and if it is
> > such a heart ache to change algorithms in this code then it probably
> > should be redesigned?
> 
> The RC4 algorithm is standard. Making the alogorithm pluggable means more
> code, more testing and more time (time which I am rather short of).

I would rather see a proper implementation later, than a poor design
decision today.

> > Also you can always compile in a module, you can not compile out
> > a 'standard' file.
> > 
> > For now could you just add
> > 	options chacha #Required by arc4random, do not remove
> > to your kernel and move on?  For me this would be an acceptable
> > developement, even releasable, way to proceed while the more
> > complex issue of how to make the kernel RNG use plagable lkm
> > lower layers.
> 
> It would have to be unconditionally added to *all* kernels. Could be
> done, I guess.

We dont have that many in base kernel configs do we?

> RC4 has been standard for many years.
Probably another rapid mode of design rather than a thoughful mode, we
have a chance to correct this here, and imho, should.

> >>> I am sure with careful though we can find a way to allow arc4random
> >>> to use a pointer that knows if the chacha code is avaliable, and use
> >>> it if so, and if not fall back to something else, or punt with an
> >>> error return.
> >> 
> >> Error return is out of the question; arc4random() is pretty fundamental.
> >> The alternative is to return no or fake random numbers, which rather
> >> misses the point of what this is for. But it can be done.
> > 
> > Arc4random works today without chacha, why would adding support for chache
> > as an optional loadable function break that?  *truely confused*
> 
> Up until now, arc4random worked with unconditional RC4.

And your wanting to just replace unconditional RC4 for unconditional chacha?
Or actuall, aleady did?

-- 
Rod Grimes                                                 rgrimes at freebsd.org