Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751899AbaKKERE (ORCPT ); Mon, 10 Nov 2014 23:17:04 -0500 Received: from mail.eperm.de ([89.247.134.16]:54320 "EHLO mail.eperm.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751316AbaKKERB (ORCPT ); Mon, 10 Nov 2014 23:17:01 -0500 X-AuthUser: sm@eperm.de From: Stephan Mueller To: Sandy Harris , Herbert Xu Cc: LKML , linux-crypto@vger.kernel.org Subject: Re: crypto: zeroization of sensitive data in af_alg Date: Tue, 11 Nov 2014 05:16:54 +0100 Message-ID: <3021915.VU7Ypy9It6@tachyon.chronox.de> User-Agent: KMail/4.14.2 (Linux/3.17.2-300.fc21.x86_64; KDE/4.14.2; x86_64; ; ) In-Reply-To: References: <1979092.odOtqL46qU@tachyon.chronox.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Montag, 10. November 2014, 21:55:43 schrieb Sandy Harris: Hi Sandy, Herbert, > On Sun, Nov 9, 2014 at 5:33 PM, Stephan Mueller wrote: > > while working on the AF_ALG interface, I saw no active zeroizations of > > memory that may hold sensitive data that is maintained outside the kernel > > crypto API cipher handles. ... > > > > I think I found the location for the first one: hash_sock_destruct that > > should be enhanced with a memset(0) of ctx->result. > > See also a thread titled "memset() in crypto code?" on the linux > crypto list. The claim is that gcc can optimise memset() away so you > need a different function to guarantee the intended results. There's a > patch to the random driver that uses a new function > memzero_explicit(), and one of the newer C standards has a different > function name for the purpose. That is a good idea. Herbert: I can prepare a patch that uses memzero_explicit. However, your current tree does not yet implement that function as it was added to Linus' tree after you pulled from it. Shall I now still use memset(0) or prepare a patch that does not yet compile by using memzero_explicit? -- Ciao Stephan -- 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/