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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 09E28C433E2 for ; Tue, 16 Jun 2020 16:07:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E369D214DB for ; Tue, 16 Jun 2020 16:07:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="anxZyJva" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732648AbgFPQHY (ORCPT ); Tue, 16 Jun 2020 12:07:24 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:54810 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732257AbgFPPrE (ORCPT ); Tue, 16 Jun 2020 11:47:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592322422; 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: in-reply-to:in-reply-to:references:references; bh=djkgmBs6vxKrnF2svfHTCwO6iJZv0MD8YpKSjFl2MGs=; b=anxZyJvaFpuLChSMwUR/a7qLSGGcT0Nzy4aiSkqCpI/xVk6zVIcE9J7iV1341dFYQpdAwe QNobub7hXN4Ms1OW18fOfvph9zqDj6d3Es9xcqmAm7V7WWOGLDbJFRK2rhytEAPFfTLrAb z8prG6hZN2mOJEmSXgQ9/SksTn2gcSw= 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-218-nWeeH7oNN9eY6skcHYs3nQ-1; Tue, 16 Jun 2020 11:46:56 -0400 X-MC-Unique: nWeeH7oNN9eY6skcHYs3nQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0B3678DEEE2; Tue, 16 Jun 2020 15:46:51 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-114-66.rdu2.redhat.com [10.10.114.66]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3EC3B60C05; Tue, 16 Jun 2020 15:46:41 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <56c2304c-73cc-8f48-d8d0-5dd6c39f33f3@redhat.com> References: <56c2304c-73cc-8f48-d8d0-5dd6c39f33f3@redhat.com> <20200616015718.7812-1-longman@redhat.com> <20200616015718.7812-2-longman@redhat.com> <20200616033035.GB902@sol.localdomain> To: Waiman Long Cc: Andrew Morton , ebiggers@kernel.org, David Howells , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , Linus Torvalds , Joe Perches , Matthew Wilcox , David Rientjes , Michal Hocko , Johannes Weiner , Dan Carpenter , David Sterba , "Jason A . Donenfeld" , linux-mm@kvack.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, linux-pm@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-amlogic@lists.infradead.org, linux-mediatek@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.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, 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, linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v4 1/3] mm/slab: Use memzero_explicit() in kzfree() MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <879078.1592322400.1@warthog.procyon.org.uk> Date: Tue, 16 Jun 2020 16:46:40 +0100 Message-ID: <879079.1592322400@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Waiman Long wrote: > The kzfree() function is normally used to clear some sensitive > information, like encryption keys, in the buffer before freeing it back > to the pool. Memset() "memset()" is all lowercase. > is currently used for buffer clearing. However unlikely, there is still a > non-zero probability I'd say "a possibility". > that and I'd move "in [the] future" here. > the compiler may choose to optimize away the > memory clearing especially if LTO is being used in the future. To make sure > that this optimization will never happen "in these cases" > , memzero_explicit(), which is introduced in v3.18, is now used in "instead of"? > kzfree() to future-proof it. Davod