From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161161AbWHDNAd (ORCPT ); Fri, 4 Aug 2006 09:00:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161193AbWHDNAd (ORCPT ); Fri, 4 Aug 2006 09:00:33 -0400 Received: from web25805.mail.ukl.yahoo.com ([217.12.10.190]:27014 "HELO web25805.mail.ukl.yahoo.com") by vger.kernel.org with SMTP id S1161161AbWHDNAc (ORCPT ); Fri, 4 Aug 2006 09:00:32 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.fr; h=Message-ID:Received:Date:From:Reply-To:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type; b=SftXVeuCtrKkpzEUmXv69+1QtiAHJeiDiq0pJ2m60cDebmEZtuSZFFYrmYd6Ljd86V3lhdBT+q4K9B82c/n8le0rBND5Lcbh8u2MxQPcE5BO6D+auMqHCcWpUgR9A8KSoKLiPVTypPUjVdXRIPqu4ZKmWapzSD67Plw3LquHg1g= ; Message-ID: <20060804130030.90361.qmail@web25805.mail.ukl.yahoo.com> Date: Fri, 4 Aug 2006 13:00:30 +0000 (GMT) From: moreau francis Reply-To: moreau francis Subject: Re : [HW_RNG] How to use generic rng in kernel space To: Michael Buesch Cc: linux-kernel@vger.kernel.org In-Reply-To: <200608012249.20324.mb@bu3sch.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Michael Buesch wrote: > The dataflow is as follows: > HW-RNG -> userspace RNGD (through /dev/hwrng) -> the daemon > checks it for sanity and puts it back into the kernel through > /dev/random -> Your driver gets the data from the /dev/random > entropy pools. Is that also true for embedded systems ? I mean we may not found any rngd on these systems. One other question now: suppose that others drivers need to use random data during their inits. At this time userspace appli still not have been started. How does it work ? > This is very neccesary, because your HW-RNG may fail and > so you may unintentionally use non-random data, if you use > the random data from the RNG directly. > The data _must_ go through userspace rngd, which does FIPS > sanity checks on the data. Well I'm working on a secure SOC which have a randown hardware which is supposed to return true random data. I understand that some self tests on the random data are needed but doing them in userspace is suprising. thanks Francis