Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754805AbXLDWEE (ORCPT ); Tue, 4 Dec 2007 17:04:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751922AbXLDWDy (ORCPT ); Tue, 4 Dec 2007 17:03:54 -0500 Received: from THUNK.ORG ([69.25.196.29]:57958 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751479AbXLDWDy (ORCPT ); Tue, 4 Dec 2007 17:03:54 -0500 Date: Tue, 4 Dec 2007 17:03:16 -0500 From: Theodore Tso To: Mike McGrath Cc: Alan Cox , Matt Mackall , 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: <20071204220316.GF7259@thunk.org> Mail-Followup-To: Theodore Tso , Mike McGrath , Alan Cox , Matt Mackall , Ray Lee , Adrian Bunk , Marc Haber , linux-kernel@vger.kernel.org References: <20071204114125.GA17310@torres.zugschlus.de> <20071204161811.GB15974@stusta.de> <2c0942db0712040854u17a830b9see663742b2716457@mail.gmail.com> <20071204165502.0a8f695e@the-village.bc.nu> <20071204180237.GU19691@waste.org> <20071204195021.GB7259@thunk.org> <20071204204036.484f11ac@the-village.bc.nu> <4755BD0C.2060808@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4755BD0C.2060808@redhat.com> 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: 1516 Lines: 35 On Tue, Dec 04, 2007 at 02:48:12PM -0600, Mike McGrath wrote: > Alan Cox wrote: >>> Here's the top 5: >>> >>> 266 28caf2c3-9766-4fe1-9e4c-d6b0ba8a0132 >>> 336 810e7126-1c69-4aff-b8b1-9db0fa8aa15a >>> 402 c8dbb9d3-a9bd-4ba6-b92e-4a294ba5a95f >>> 884 06e84493-e024-44b1-9b32-32d78af04039 >>> 931 e2b67e1d-e325-4740-b938-795addb45280 >>> >>> The left number is times this month someone has submitted a profile with >>> that UUID. If we take the last one as an example has come from over 800 >>> IP's in the last 20 days. It seems very unlikely that one person would >>> find his way to 800 different IP's this month. Let me know if you'd >>> like more. >>> > Background - Smolt runs this during its install: > > /bin/cat /proc/sys/kernel/random/uuid > /etc/sysconfig/hw-uuid > > For most users this would be run by the RPM %post scripts during install > from anaconda. For some reason there are some UUID's (like those listed > above) that come up more often then it seems they should if they are truly > random. Would this be by any chance using kickstart where there is no user interaction, and no way of gathering entropy during the install process? The random number generator isn't *magic* you know.... - 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/