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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,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 3F617C2BA2B for ; Mon, 13 Apr 2020 21:33:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CCDE7206DA for ; Mon, 13 Apr 2020 21:33:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CCDE7206DA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=perches.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5212A8E0005; Mon, 13 Apr 2020 17:33:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4AA278E0001; Mon, 13 Apr 2020 17:33:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 34AB48E0005; Mon, 13 Apr 2020 17:33:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0126.hostedemail.com [216.40.44.126]) by kanga.kvack.org (Postfix) with ESMTP id 1A5328E0001 for ; Mon, 13 Apr 2020 17:33:48 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id C82375828 for ; Mon, 13 Apr 2020 21:33:47 +0000 (UTC) X-FDA: 76704134094.10.cart87_5b4db42531c02 X-HE-Tag: cart87_5b4db42531c02 X-Filterd-Recvd-Size: 4564 Received: from smtprelay.hostedemail.com (smtprelay0125.hostedemail.com [216.40.44.125]) by imf35.hostedemail.com (Postfix) with ESMTP for ; Mon, 13 Apr 2020 21:33:47 +0000 (UTC) Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay06.hostedemail.com (Postfix) with ESMTP id D45AF18027F9D; Mon, 13 Apr 2020 21:33:46 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: badge84_5a5696689f027 X-Filterd-Recvd-Size: 3380 Received: from XPS-9350.home (unknown [47.151.136.130]) (Authenticated sender: joe@perches.com) by omf07.hostedemail.com (Postfix) with ESMTPA; Mon, 13 Apr 2020 21:33:40 +0000 (UTC) Message-ID: Subject: Re: [PATCH 2/2] crypto: Remove unnecessary memzero_explicit() From: Joe Perches To: Waiman Long , Andrew Morton , David Howells , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , Linus Torvalds , Matthew Wilcox , David Rientjes Cc: linux-mm@kvack.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-crypto@vger.kernel.org, linux-s390@vger.kernel.org, linux-pm@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-mediatek@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-ppp@vger.kernel.org, wireguard@lists.zx2c4.com, linux-wireless@vger.kernel.org, devel@driverdev.osuosl.org, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-fscrypt@vger.kernel.org, ecryptfs@vger.kernel.org, kasan-dev@googlegroups.com, linux-bluetooth@vger.kernel.org, linux-wpan@vger.kernel.org, linux-sctp@vger.kernel.org, linux-nfs@vger.kernel.org, tipc-discussion@lists.sourceforge.net, cocci@systeme.lip6.fr, linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org Date: Mon, 13 Apr 2020 14:31:32 -0700 In-Reply-To: <20200413211550.8307-3-longman@redhat.com> References: <20200413211550.8307-1-longman@redhat.com> <20200413211550.8307-3-longman@redhat.com> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.34.1-2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, 2020-04-13 at 17:15 -0400, Waiman Long wrote: > Since kfree_sensitive() will do an implicit memzero_explicit(), there > is no need to call memzero_explicit() before it. Eliminate those > memzero_explicit() and simplify the call sites. 2 bits of trivia: > diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c [] > @@ -391,10 +388,7 @@ int sun8i_ce_aes_setkey(struct crypto_skcipher *tfm, const u8 *key, > dev_dbg(ce->dev, "ERROR: Invalid keylen %u\n", keylen); > return -EINVAL; > } > - if (op->key) { > - memzero_explicit(op->key, op->keylen); > - kfree(op->key); > - } > + kfree_sensitive(op->key); > op->keylen = keylen; > op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA); > if (!op->key) It might be a defect to set op->keylen before the kmemdup succeeds. > @@ -416,10 +410,7 @@ int sun8i_ce_des3_setkey(struct crypto_skcipher *tfm, const u8 *key, > if (err) > return err; > > - if (op->key) { > - memzero_explicit(op->key, op->keylen); > - kfree(op->key); > - } > + free_sensitive(op->key, op->keylen); Why not kfree_sensitive(op->key) ?