From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754940AbXLDWSr (ORCPT ); Tue, 4 Dec 2007 17:18:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752085AbXLDWS1 (ORCPT ); Tue, 4 Dec 2007 17:18:27 -0500 Received: from mx1.redhat.com ([66.187.233.31]:43747 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751973AbXLDWS0 (ORCPT ); Tue, 4 Dec 2007 17:18:26 -0500 Message-ID: <4755D0E3.9090303@redhat.com> Date: Tue, 04 Dec 2007 16:12:51 -0600 From: Mike McGrath User-Agent: Thunderbird 2.0.0.5 (X11/20070719) MIME-Version: 1.0 To: Theodore Tso , Mike McGrath , 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? 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> <20071204220316.GF7259@thunk.org> In-Reply-To: <20071204220316.GF7259@thunk.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Theodore Tso wrote: > 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.... > This is certainly possible but I think its unlikely. Not many people know about smolt. Most of our profiles come from prompting people during firstboot which gets skipped when people are running kickstart. I'll make sure to follow up with people that report a duplicate. -Mike