Date: Sun, 16 Apr 2017 13:13:22 +0100 From: Mark R V Murray <markm@FreeBSD.org> To: rgrimes@FreeBSD.org Cc: src-committers <src-committers@FreeBSD.org>, svn-src-all@FreeBSD.org, svn-src-head@FreeBSD.org Subject: Re: svn commit: r317015 - in head/sys: boot/forth conf crypto/chacha20 dev/random libkern sys Message-ID: <60A59E27-47CD-4552-8265-0E60C09E1966@FreeBSD.org> In-Reply-To: <201704161207.v3GC7adp016485@pdx.rh.CN85.dnsmgr.net> References: <201704161207.v3GC7adp016485@pdx.rh.CN85.dnsmgr.net>
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> On 16 Apr 2017, at 13:07, Rodney W. Grimes = <freebsd@pdx.rh.CN85.dnsmgr.net> wrote: >=20 >>> =46rom 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. >>=20 >> This may take a while, and I'm already behind on RNG jobs. >=20 > 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). > Also you can always compile in a module, you can not compile out > a 'standard' file. >=20 > 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. RC4 has been standard for many years. >>> 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. >>=20 >> 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. >=20 > 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. M --=20 Mark R V Murray
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