Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753965AbXLKN6g (ORCPT ); Tue, 11 Dec 2007 08:58:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752367AbXLKN62 (ORCPT ); Tue, 11 Dec 2007 08:58:28 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:1298 "EHLO spitz.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752209AbXLKN62 (ORCPT ); Tue, 11 Dec 2007 08:58:28 -0500 Date: Mon, 10 Dec 2007 16:37:37 +0000 From: Pavel Machek To: Theodore Tso , Mike McGrath , Matt Mackall , 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: <20071210163736.GA6107@ucw.cz> References: <20071204180237.GU19691@waste.org> <20071204195021.GB7259@thunk.org> <20071204204036.484f11ac@the-village.bc.nu> <20071204210827.GE19691@waste.org> <4755C423.60907@redhat.com> <20071204221525.GG19691@waste.org> <4755D350.1080801@redhat.com> <20071204223345.GJ19691@waste.org> <4756B50B.3060100@redhat.com> <20071205144934.GL7259@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071205144934.GL7259@thunk.org> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1177 Lines: 24 On Wed 2007-12-05 09:49:34, Theodore Tso wrote: > On Wed, Dec 05, 2007 at 08:26:19AM -0600, Mike McGrath wrote: > > > > Ok, whats going on here is an issue with how the smolt RPM installs the > > UUID and how Fedora's Live CD does an install. It's a complete false alarm > > on the kernel side, sorry for the confusion. > > BTW, You may be better off using "uuidgen -t" to generate the UUID in > the smolt RPM, since that will use 12 bits of randomness from > /dev/random, plus the MAC, address and timestamp. So even if there is > zero randomness in /dev/random, and the time is January 1, 1970, at > least the MAC will contribute some uniqueness to the UUID. I thought that /dev/random blocks when 0 entropy is available...? I'd expect uuid generation to block, not to issue duplicates. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- 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/