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=-5.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 4AF11C2BBC7 for ; Mon, 13 Apr 2020 21:53:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 26D8B20644 for ; Mon, 13 Apr 2020 21:53:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ZtXlUR+j" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389296AbgDMVw5 (ORCPT ); Mon, 13 Apr 2020 17:52:57 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:43109 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2389299AbgDMVwp (ORCPT ); Mon, 13 Apr 2020 17:52:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1586814764; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wxqewLP4iDn0WQn56N4JoZnVO/VnkSCHun6WFS8TA58=; b=ZtXlUR+jTPnPN3iCA/WKmMCiPRo/hAbmohSMyJGHGYT5o6A8cEKHi7627TDTDbNJ1TeeIo p8bBsVkbQlAOOZyLatf6AQfHgPPE8r3rc+shdpzSFQy3NMuUjhIpz78Cva0U8Z66l77Jjy UVK9pTbtiTQkMRsi9aA4mLn8axE6Yp8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-238-R_QYnAHVPD67nMQL-Amo0w-1; Mon, 13 Apr 2020 17:52:38 -0400 X-MC-Unique: R_QYnAHVPD67nMQL-Amo0w-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id F1B928018AA; Mon, 13 Apr 2020 21:52:32 +0000 (UTC) Received: from llong.remote.csb (ovpn-115-28.rdu2.redhat.com [10.10.115.28]) by smtp.corp.redhat.com (Postfix) with ESMTP id AB5E15C1B2; Mon, 13 Apr 2020 21:52:24 +0000 (UTC) Subject: Re: [PATCH 2/2] crypto: Remove unnecessary memzero_explicit() To: Joe Perches , 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 References: <20200413211550.8307-1-longman@redhat.com> <20200413211550.8307-3-longman@redhat.com> From: Waiman Long Organization: Red Hat Message-ID: <7e13a94b-2e92-850f-33f7-0f42cfcd9009@redhat.com> Date: Mon, 13 Apr 2020 17:52:24 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On 4/13/20 5:31 PM, Joe Perches wrote: > 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. It could be. I can move it down after the op->key check. >> @@ -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) ? Oh, it is a bug. I will send out v2 to fix that. Thanks for spotting it. Cheers, Longman > >