From owner-freebsd-arch@FreeBSD.ORG Mon Aug 19 07:40:14 2013 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 837AD658; Mon, 19 Aug 2013 07:40:14 +0000 (UTC) (envelope-from mark@grondar.org) Received: from gromit.grondar.org (grandfather.grondar.org [IPv6:2a01:348:0:15:5d59:5c20:0:2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 444D02874; Mon, 19 Aug 2013 07:40:14 +0000 (UTC) Received: from graveyard.grondar.org ([88.96.155.33] helo=gronkulator.grondar.org) by gromit.grondar.org with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.80.1 (FreeBSD)) (envelope-from ) id 1VBK4N-000LiJ-K8; Mon, 19 Aug 2013 08:40:12 +0100 Subject: Re: random(4) plugin infrastructure for mulitple RNG in a modular fashion Mime-Version: 1.0 (Mac OS X Mail 6.5 \(1508\)) Content-Type: multipart/signed; boundary="Apple-Mail=_303BAD32-22C2-4AAD-80BF-6DA5FB281728"; protocol="application/pgp-signature"; micalg=pgp-sha512 From: Mark R V Murray In-Reply-To: Date: Mon, 19 Aug 2013 08:40:06 +0100 Message-Id: References: <20130807183112.GA79319@dragon.NUXI.org> <86pptfnu33.fsf@nine.des.no> <20130815231713.GD76666@x96.org> <20130816002625.GE76666@x96.org> <9B274F48-0C88-4117-BEAC-1A555772A3C5@grondar.org> <86a9kf733d.fsf@nine.des.no> <0C97B866-A169-4141-8368-AA7F5B5382F4@grondar.org> <861u5r71zi.fsf@nine.des.no> <892B11BD-396D-4F82-B97C-753F72CA494D@grondar.org> <86r4dr5j3p.fsf@nine.des.no> <4C1BD77C-8C6B-4044-9285-5978A3BC4B70@kientzle.com> <12B58C72-CFE3-4AD4-AD03-462A10E431D9@bsdimp.com> <3513A465-AD8D-4DDC-9408-2F89F9B86404@grondar.org> To: Warner Losh X-Mailer: Apple Mail (2.1508) X-SA-Score: -2.2 Cc: Tim Kientzle , FreeBSD-arch Arch , secteam@freebsd.org, =?iso-8859-1?Q?Dag-Erling_Sm=F8rgrav?= X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 19 Aug 2013 07:40:14 -0000 --Apple-Mail=_303BAD32-22C2-4AAD-80BF-6DA5FB281728 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 On 19 Aug 2013, at 08:24, Warner Losh wrote: >> How would they get a score, and how would it be decided which is = better? How is the score "calibrated"? >=20 > For timecounters, we make judgements based on how good or bad we think = the timekeeping ability of the underlying device. I'd imagine that we'd = rate the hardware RNGs high, and the fallback means of harvesting = entropy from interrupts medium, and anything that's really really bad as = low. This would allow for the hardware RNGs to override the other = sources of entropy, while still allowing fallback to reasonable entropy = on devices that are known suspect (While still allowing the pig-headed = and/or externally constrained folks to use the bad sources). Aaah - so its a coarse good/average/bad thing, rather than a = fine-grained number giving precise/critical ordering? > For the mixers, the scoring mechanism makes less sense. You'd want = more of an ordered list specified by the user to dictate policy to = choose between nothing, fortuna and yarrow. The mixers won't care, correct. As for the rest, its a bit of a tree of = choices: HW branch - choice of "good" sources only (?). SW branch - = choice of Yarrow/Fortuna and which sources (currently four, but will be = increased) to harvest from. > You'd also want a parameter to deal with failure here: panic or block. Right, and a default for GENERIC. M --=20 Mark R V Murray --Apple-Mail=_303BAD32-22C2-4AAD-80BF-6DA5FB281728 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.20 (Darwin) Comment: GPGTools - http://gpgtools.org iQCVAwUBUhHL1t58vKOKE6LNAQrfxAP/c1hmEoOkG5Ty8aFjBUVm4vmx1nSFvHj1 LTVyMGNsCc6IkunN56msq2ACGmXxVd8is3EK0hIldlrwnL+couWwzNpHikqdbzDu pTSfPUCtMHYAW8Hx+R6T+aFaGjsXMeor94eT+OBMg97+T0eSgt17OB8Kxvq1kW+e iPkAy7TnK1o= =6a86 -----END PGP SIGNATURE----- --Apple-Mail=_303BAD32-22C2-4AAD-80BF-6DA5FB281728--