From owner-freebsd-security@FreeBSD.ORG Thu Sep 6 17:18:25 2012 Return-Path: Delivered-To: freebsd-security@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 664) id 2ABB01065670; Thu, 6 Sep 2012 17:18:25 +0000 (UTC) Date: Thu, 6 Sep 2012 10:18:24 -0700 From: David O'Brien To: RW Message-ID: <20120906171824.GC14757@dragon.NUXI.org> References: <201208221843.q7MIhLU4077951@svn.freebsd.org> <5043DBAF.40506@FreeBSD.org> <20120903005708.7082f230@gumby.homeunix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120903005708.7082f230@gumby.homeunix.com> X-Operating-System: FreeBSD 10.0-CURRENT X-to-the-FBI-CIA-and-NSA: HI! HOW YA DOIN? can i haz chizburger? User-Agent: Mutt/1.5.20 (2009-06-14) Cc: Arthur Mesh , freebsd-security@freebsd.org Subject: Re: svn commit: r239569 - head/etc/rc.d X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: obrien@freebsd.org List-Id: "Security issues \[members-only posting\]" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 06 Sep 2012 17:18:25 -0000 ** Please do not remove the CC: / FROM: recipients from replies ** On Mon, Sep 03, 2012 at 12:57:08AM +0100, RW wrote: > The more significant problem is that initrandom dumps some very > low-grade entropy into /dev/random before the entropy file (see below). > Since /dev/random has very limited buffering, and processes the buffers > in a timed loop, Arthur and I are aware of that. I believe this behavior of our yarrow implementation is poorly documented. > IMO the order should be reversed or the low-grade > stuff should be piped through sha256. We considered that. Arthur wanted to do it sooner, but I'm concerned about impact of multiple sha256 invocations on a large amount of data on low-end MIPS. I did some measurements on one of our lower-end Octeon MIPS devices and lowest-end ARM devices. My concerns are based on the Octeon MIPS result. I have zero concern for ARM devices [based on my very limited access to ARM devices]. [I don't have the results anymore thus they aren't supplied here] -- -- David (obrien@FreeBSD.org)