Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753348AbXLHSZo (ORCPT ); Sat, 8 Dec 2007 13:25:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753144AbXLHSZe (ORCPT ); Sat, 8 Dec 2007 13:25:34 -0500 Received: from thunk.org ([69.25.196.29]:38853 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751230AbXLHSZd (ORCPT ); Sat, 8 Dec 2007 13:25:33 -0500 Date: Sat, 8 Dec 2007 13:24:31 -0500 From: Theodore Tso To: Matt Mackall Cc: Mike McGrath , Jon Masters , Alan Cox , Ray Lee , Adrian Bunk , Marc Haber , linux-kernel@vger.kernel.org Subject: Re: Why does reading from /dev/urandom deplete entropy so much? Message-ID: <20071208182431.GN17037@thunk.org> Mail-Followup-To: Theodore Tso , Matt Mackall , Mike McGrath , Jon Masters , Alan Cox , Ray Lee , Adrian Bunk , Marc Haber , linux-kernel@vger.kernel.org References: <20071204221525.GG19691@waste.org> <4755D350.1080801@redhat.com> <20071204223345.GJ19691@waste.org> <4756B50B.3060100@redhat.com> <20071205144934.GL7259@thunk.org> <1197099477.20786.149.camel@perihelion> <20071208173204.GI17037@thunk.org> <475AD585.7020908@redhat.com> <20071208174908.GJ17037@thunk.org> <20071208181525.GL19691@waste.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071208181525.GL19691@waste.org> User-Agent: Mutt/1.5.15+20070412 (2007-04-11) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on thunker.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1129 Lines: 23 On Sat, Dec 08, 2007 at 12:15:25PM -0600, Matt Mackall wrote: > > It might be better for us to just improve the pool initialization. > That'll improve the out of the box experience for everyone. > Yeah, I agree. Although keep in mind, doing things like mixing in MAC address and DMI information (which we can either do in the kernel or by trying to get all of the distro's to add that into their /etc/init.d/random script --- all several hundred or thousand distro's in the world :-), will help improve things like UUID uniqueness, it doesn't necessarily guarantee /dev/urandom and UUID *unpredictability*. In order to do that we really do need to improve the amount of hardware entropy we can mix into the system. This is a hard problem, but as more people are relying on these facilities, it's something we need to think about quite a bit more! - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/