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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A39A1C433E0 for ; Sun, 14 Jun 2020 20:02:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 778B82071A for ; Sun, 14 Jun 2020 20:02:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727940AbgFNUCC (ORCPT ); Sun, 14 Jun 2020 16:02:02 -0400 Received: from smtprelay0188.hostedemail.com ([216.40.44.188]:39492 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726844AbgFNUB4 (ORCPT ); Sun, 14 Jun 2020 16:01:56 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay02.hostedemail.com (Postfix) with ESMTP id ABA7C15C6; Sun, 14 Jun 2020 20:01:54 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: light02_2e08cc026df0 X-Filterd-Recvd-Size: 1857 Received: from XPS-9350.home (unknown [47.151.136.130]) (Authenticated sender: joe@perches.com) by omf07.hostedemail.com (Postfix) with ESMTPA; Sun, 14 Jun 2020 20:01:53 +0000 (UTC) Message-ID: <803557cc672ef0bcd9565c7d5d78e7053388f5d7.camel@perches.com> Subject: Re: [PATCH] coccinelle: api: add kzfree script From: Joe Perches To: efremov@linux.com, Julia Lawall , Dan Carpenter Cc: cocci@systeme.lip6.fr, linux-kernel@vger.kernel.org Date: Sun, 14 Jun 2020 13:01:51 -0700 In-Reply-To: <345c783b-a8cf-9dd1-29c6-d32b9b29053f@linux.com> References: <20200604140805.111613-1-efremov@linux.com> <345c783b-a8cf-9dd1-29c6-d32b9b29053f@linux.com> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.36.2-0ubuntu1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2020-06-14 at 22:42 +0300, Denis Efremov wrote: > On 6/4/20 7:27 PM, Joe Perches wrote: > > On Thu, 2020-06-04 at 17:08 +0300, Denis Efremov wrote: > > > Check for memset() with 0 followed by kfree(). > > > > Perhaps those uses should be memzero_explicit or kvfree_sensitive. > > > Is it safe to suggest to use kzfree instead of memzero_explicit && kfree? > Or it would be better to use kvfree_sensitive in this case. > kzfree uses memset(0) with no barrier_data. > > For example: > diff -u -p a/drivers/crypto/inside-secure/safexcel_hash.c b/drivers/crypto/inside-secure/safexcel_hash.c [] > @@ -1081,8 +1081,7 @@ static int safexcel_hmac_init_pad(struct > } > > /* Avoid leaking */ > - memzero_explicit(keydup, keylen); > - kfree(keydup); > + kzfree(keydup); It would be better to use kvfree_sensitive()