From owner-freebsd-arch@FreeBSD.ORG Mon Aug 19 22:02:01 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 BB431416 for ; Mon, 19 Aug 2013 22:02:01 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from mail-oa0-f52.google.com (mail-oa0-f52.google.com [209.85.219.52]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 7D8222BAC for ; Mon, 19 Aug 2013 22:02:01 +0000 (UTC) Received: by mail-oa0-f52.google.com with SMTP id n12so4457182oag.39 for ; Mon, 19 Aug 2013 15:01:54 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-gm-message-state:sender:subject:mime-version:content-type:from :in-reply-to:date:cc:content-transfer-encoding:message-id:references :to; bh=dpwboo5CV01TfcNfbWFFptxA1ZMeargsxHjt1kAE8jU=; b=gH8ZlsVhAJhlUIAeXA9wvFLAoaIId+LOvTI1oDsg+/2BP+YLljAg0oQyKcN+c98cXW JnAsB1ePCC+m7LBAvXUBhIaIeXdPjP1kFEYoNQGFWgX1CIBAQZBMQoNjtCho/vYZz9bo S71nOJrkXNCP8wn3zu337Z68usqMCAd9cdiNOGOKy5VdaAlm+Ol5Y7sDP6Xu2ZhiH9xk nXAUGck7xbkauWq07ml1z74TUu80MfFVsfi1e945evNMsW8Sz16WaTCAywB0INEDLNXj mhvGGq+NDusJ030mbxCljV10632gwVSaCcCkw8yDcJT9a6Y5Y6I+Z7ZI5Qp2wu5gvx1O ANpg== X-Gm-Message-State: ALoCoQnOMtUR3QCKbPdL8i3z4/v9TIo2r+oF6L0fk7YgBhrxlTuiGE9dLpe8KQcURtJusz5kmHqS X-Received: by 10.60.131.69 with SMTP id ok5mr4182947oeb.70.1376949713998; Mon, 19 Aug 2013 15:01:53 -0700 (PDT) Received: from monkey-bot.int.fusionio.com ([209.117.142.2]) by mx.google.com with ESMTPSA id g1sm19684576oeq.6.1969.12.31.16.00.00 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 19 Aug 2013 15:01:53 -0700 (PDT) Sender: Warner Losh Subject: Re: random(4) plugin infrastructure for mulitple RNG in a modular fashion Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: text/plain; charset=us-ascii From: Warner Losh In-Reply-To: Date: Mon, 19 Aug 2013 16:01:52 -0600 Content-Transfer-Encoding: quoted-printable Message-Id: <629B621F-B166-4D66-A4E6-ED9B966E7A21@bsdimp.com> 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: Mark R V Murray X-Mailer: Apple Mail (2.1085) 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 22:02:01 -0000 On Aug 19, 2013, at 1:40 AM, Mark R V Murray wrote: > 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). >=20 > Aaah - so its a coarse good/average/bad thing, rather than a = fine-grained number giving precise/critical ordering? >=20 >> 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. >=20 > 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. >=20 >> You'd also want a parameter to deal with failure here: panic or = block. >=20 > Right, and a default for GENERIC. Exactly... Warner