Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753732AbaBLSUJ (ORCPT ); Wed, 12 Feb 2014 13:20:09 -0500 Received: from quartz.orcorp.ca ([184.70.90.242]:59015 "EHLO quartz.orcorp.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752966AbaBLSUG (ORCPT ); Wed, 12 Feb 2014 13:20:06 -0500 Date: Wed, 12 Feb 2014 11:20:00 -0700 From: Jason Gunthorpe To: Jason Cooper Cc: Arnd Bergmann , keescook@chromium.org, devicetree@vger.kernel.org, Laura Abbott , linux-kernel@vger.kernel.org, Rob Herring , Kumar Gala , Grant Likely , linux-arm-kernel@lists.infradead.org Subject: Re: [RFC/PATCH 0/3] Add devicetree scanning for randomness Message-ID: <20140212182000.GJ5554@obsidianresearch.com> References: <1392168805-14200-1-git-send-email-lauraa@codeaurora.org> <201402121251.06280.arnd@arndb.de> <20140212174554.GM27395@titan.lakedaemon.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140212174554.GM27395@titan.lakedaemon.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-Broken-Reverse-DNS: no host name found for IP address 10.0.0.161 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 12, 2014 at 12:45:54PM -0500, Jason Cooper wrote: > The bootloader would then load this file into ram, and pass the > address/size to the kernel either via dt, or commandline. kaslr (run in > the decompressor) would consume some of this randomness, and then > random.c would consume the rest in a non-crediting initialization. Sure is a neat idea, but I think in general it would probably be smart to include the entire FDT blob in the early random pool, that way you get MACs and other machine unique data too. >From there it is a small step to encourage bootloaders to include boot-time-variable data in the DT like like 'boot time of day', 'cycle counter', 'random blob', etc. Then you just need the bootloader to dump the random-seed file into a DT property. Or have the bootloader fetch randomness from any HWRNG it has a driver for. (eg a TPM) Jason -- 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/