From owner-freebsd-security@FreeBSD.ORG Sat Sep 15 11:10:09 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 748E91065678 for ; Sat, 15 Sep 2012 11:10:09 +0000 (UTC) (envelope-from markm@FreeBSD.org) Received: from gromit.grondar.org (grandfather.grondar.org [IPv6:2a01:348:0:15:5d59:5c20:0:2]) by mx1.freebsd.org (Postfix) with ESMTP id 1069C8FC18 for ; Sat, 15 Sep 2012 11:10:09 +0000 (UTC) Received: from uucp by gromit.grondar.org with local-rmail (Exim 4.77 (FreeBSD)) (envelope-from ) id 1TCqGF-00064a-PA for freebsd-security@freebsd.org; Sat, 15 Sep 2012 12:10:07 +0100 Received: from localhost ([127.0.0.1] helo=groundzero.grondar.org) by groundzero.grondar.org with esmtp (Exim 4.77 (FreeBSD)) (envelope-from ) id 1TCqDg-000N6O-Nv; Sat, 15 Sep 2012 12:07:28 +0100 To: Ben Laurie 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> From: Mark Murray Date: Sat, 15 Sep 2012 12:07:28 +0100 Message-Id: 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: Sat, 15 Sep 2012 11:10:09 -0000 Ben Laurie writes: > > Are you aware of Yarrow's approach to poor entropy while harvesting? > > Yes. I am _only_ talking about fixes for the current practice of > discarding input - once Yarrow gets to eat input, then its all fine, > but as you say, you don't want to run Yarrow over all input because it > is too expensive. Correct. > So, you plan to xor input with itself, instead of discarding if it > fills the buffer. My point is that unfortunate choice of input can > result in the input cancelling itself out. That means that diverse input should be used, and that is the intent anyway. Hashing _certain_ input in /etc/rc.d/initrandom is also attractive. > This is not part of Yarrow - Yarrow specifies that you hash all > inputs, not xor or discard them :-) Beyond nitpicking. How the data is harvested is not discussed in much detail. Here, I'm chunking the file input up, instead of taking it piecemeal. In each case, the harvested data is handed over to Yarrow as a series of data "events". Keystrokes, mouse events, interrupts or uio() calls are all such events, and many more are possible as input. M -- Mark R V Murray Cert APS(Open) Dip Phys(Open) BSc Open(Open) BSc(Hons)(Open) Pi: 132511160