From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 91D5EC43334 for ; Tue, 5 Jul 2022 23:13:01 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Lcz3v6HF1z3c61 for ; Wed, 6 Jul 2022 09:12:59 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=zytor.com header.i=@zytor.com header.a=rsa-sha256 header.s=2022060401 header.b=KoHiZKsE; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=zytor.com (client-ip=198.137.202.136; helo=mail.zytor.com; envelope-from=hpa@zytor.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=zytor.com header.i=@zytor.com header.a=rsa-sha256 header.s=2022060401 header.b=KoHiZKsE; dkim-atps=neutral Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Lcz3G018wz3bl3 for ; Wed, 6 Jul 2022 09:12:24 +1000 (AEST) Received: from [127.0.0.1] ([73.223.250.219]) (authenticated bits=0) by mail.zytor.com (8.17.1/8.15.2) with ESMTPSA id 265NBnGE1003711 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Tue, 5 Jul 2022 16:11:50 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 265NBnGE1003711 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2022060401; t=1657062712; bh=Y98dqt5En+kS/P/7IMzby9wcUq/7fVTjOsj4m2LkPGI=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=KoHiZKsEicJF3HWW8BYUbNDtijdyk2YC30lpGok5A71WKH5jN4kSF+1k/ILd0x9By qt8xe3MS+M3LxdPaft1n7lcyMixtVdJ5SQYbrobuHAXvXZD91dHJDhsiyrj0xX6oEB UzBMdQKEXifwQOtQj+6um92/xSJJMJAJk/eweAx0I6RYNd0HPoR17l0lZTdhk7AUif NSyyZN5L500jyETF72C6IrByv8jv42HDJSrxzOzuSo6byDKD6nExbO6sf5LLBoXwBl hJl0pswjsA5H80PdAU7gimYJT6uwlh8+RWtIOHDI250cjEOA3EOFzWqjhIcySx1ZiD mZSs9tkVChZvA== Date: Tue, 05 Jul 2022 16:11:45 -0700 From: "H. Peter Anvin" To: Borislav Petkov Subject: Re: [PATCH] random: remove CONFIG_ARCH_RANDOM and "nordrand" User-Agent: K-9 Mail for Android In-Reply-To: References: <20220705190121.293703-1-Jason@zx2c4.com> <11C903CC-22A7-48EE-AD63-E71CC8D28B88@zytor.com> Message-ID: <805B66CB-D847-4547-B6EE-C4FB72B75765@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-s390@vger.kernel.org, "Jason A. Donenfeld" , Arnd Bergmann , Will Deacon , Greg Kroah-Hartman , Catalin Marinas , Heiko Carstens , x86@kernel.org, linux-kernel@vger.kernel.org, Alexander Gordeev , linuxppc-dev@lists.ozlabs.org, Thomas Gleixner , linux-arm-kernel@lists.infradead.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On July 5, 2022 3:00:04 PM PDT, Borislav Petkov wrote: >On Tue, Jul 05, 2022 at 02:50:34PM -0700, H=2E Peter Anvin wrote: >> It's just math=2E The only variable is your confidence level, i=2Ee=2E = at >> what level do you decide that the likelihood of pure chance is way >> smaller than the likelihood of hardware failure=2E > >That might be but the likelyhood of certain BIOSes dropping the ball >after resume is 100%: > >7879fc4bdc75 ("x86/rdrand: Sanity-check RDRAND output") > What I'm wondering is if we shouldn't be simply instrument *every* invocat= ion, and set the trust to zero if we ever trip it=2E