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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ACD1CC55178 for ; Fri, 23 Oct 2020 20:51:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5E8A720882 for ; Fri, 23 Oct 2020 20:51:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756410AbgJWUvK (ORCPT ); Fri, 23 Oct 2020 16:51:10 -0400 Received: from helcar.hmeau.com ([216.24.177.18]:41358 "EHLO fornost.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756401AbgJWUvJ (ORCPT ); Fri, 23 Oct 2020 16:51:09 -0400 Received: from gwarestrin.arnor.me.apana.org.au ([192.168.0.7]) by fornost.hmeau.com with smtp (Exim 4.92 #5 (Debian)) id 1kW41b-0005iu-Pu; Sat, 24 Oct 2020 07:51:01 +1100 Received: by gwarestrin.arnor.me.apana.org.au (sSMTP sendmail emulation); Sat, 24 Oct 2020 07:50:59 +1100 Date: Sat, 24 Oct 2020 07:50:59 +1100 From: Herbert Xu To: Arvind Sankar Cc: "David S. Miller" , "linux-crypto@vger.kernel.org" , Eric Biggers , David Laight , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/5] crypto: Use memzero_explicit() for clearing state Message-ID: <20201023205059.GD27708@gondor.apana.org.au> References: <20201023192203.400040-1-nivedita@alum.mit.edu> <20201023192203.400040-2-nivedita@alum.mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201023192203.400040-2-nivedita@alum.mit.edu> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 23, 2020 at 03:21:59PM -0400, Arvind Sankar wrote: > Without the barrier_data() inside memzero_explicit(), the compiler may > optimize away the state-clearing if it can tell that the state is not > used afterwards. At least in lib/crypto/sha256.c:__sha256_final(), the > function can get inlined into sha256(), in which case the memset is > optimized away. Please only convert sha256 and not everything. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt