From owner-freebsd-security@FreeBSD.ORG Fri Sep 14 21:01:17 2012 Return-Path: Delivered-To: freebsd-security@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id B39E9106566B; Fri, 14 Sep 2012 21:01:17 +0000 (UTC) (envelope-from benlaurie@gmail.com) Received: from mail-vc0-f182.google.com (mail-vc0-f182.google.com [209.85.220.182]) by mx1.freebsd.org (Postfix) with ESMTP id ECA028FC16; Fri, 14 Sep 2012 21:01:16 +0000 (UTC) Received: by vcbfw7 with SMTP id fw7so6985530vcb.13 for ; Fri, 14 Sep 2012 14:01:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=PY32MapT3juPnJSinyC4lM0KECVICBteqRVVp2lWSQg=; b=Dv64xnmhjrfe32AyWnUFnSD7IfzTsCUTEHUxHwYUiLypNgAAda9lxRltWYGpcPWcBZ PmWq6sJbcEcxckTRQ3xC95YxDThLWDFqsYIDVsyUlNTy2JRhH5BXcKzbau1yeWVRMwpv M+lL3d9tQhMXdi8VZaHh9BwhwcjuIbbma4o70McVqhzyfID8kGMWJKR2QFKLkHfYYW10 Nf81JYxMU5rl6SsX1Mu1SanNXjywQZUySYQmOfk34mn2+P/EGOQvYoQ2g6nq+7AFm3qt zsNFnCOaXybByIbaZqgKOrOT76Hy40rKtHAYK1L5BB6GAJprUvL6SWS4fM1ijltTSDTi dWKg== MIME-Version: 1.0 Received: by 10.52.33.130 with SMTP id r2mr259096vdi.43.1347656476068; Fri, 14 Sep 2012 14:01:16 -0700 (PDT) Sender: benlaurie@gmail.com Received: by 10.58.79.243 with HTTP; Fri, 14 Sep 2012 14:01:15 -0700 (PDT) In-Reply-To: References: <50453686.9090100@FreeBSD.org> <20120911082309.GD72584@dragon.NUXI.org> <504F0687.7020309@FreeBSD.org> <201209121628.18088.jhb@freebsd.org> <5050F477.8060409@FreeBSD.org> <20120912213141.GI14077@x96.org> <20120913052431.GA15052@dragon.NUXI.org> Date: Fri, 14 Sep 2012 22:01:15 +0100 X-Google-Sender-Auth: Ew4JdS9vGphjgscRNAhdpVlk82g Message-ID: From: Ben Laurie To: Mark Murray Content-Type: text/plain; charset=ISO-8859-1 Cc: Arthur Mesh , Ian Lepore , Doug Barton , freebsd-security@freebsd.org, RW , "Bjoern A. Zeeb" Subject: Re: svn commit: r239569 - head/etc/rc.d X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Security issues \[members-only posting\]" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 14 Sep 2012 21:01:17 -0000 On Fri, Sep 14, 2012 at 9:15 PM, Mark Murray wrote: > Ben Laurie writes: >> What I am trying to do is extract whatever entropy there is in the >> input. You appear to be saying that there's no point adding extra >> entropy because it is estimated at zero. This makes no sense to me. > > What I am trying to say is that it doesn't matter if by some coincidence > certain harvested file fragments contain zero. Furthermore, it doesn't > matter if you feed /dev/random a whole bunch of zeros (except in the > case where that swamps out other harvested events, and it is that > problem we are trying to solve, amonmgst others). I agree with this. > My proposed solution is intended so address, if not solve that problem, > by preventing file writes from filling up the harvest queue. Yarrow > already has pretty good data hashing; there is no point in duplicating > that. Fine: then when the queue fills, run the Yarrow algorithm. If not, then whatever you run instead must also be sound. XOR isn't. > Note that I have already agreed that external preconditioning of the > data is a good idea; I like the idea of compression and some external > hashing (but not the speed of these duting boot). I don't, because you can't rely on it. That is, I'm not against it, but we can't rely on it. > Others may work, but > ultimately I trust Yarrow more. > > M > -- > Mark R V Murray > Cert APS(Open) Dip Phys(Open) BSc Open(Open) BSc(Hons)(Open) > Pi: 132511160 >