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=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 158FAC3815B for ; Wed, 15 Apr 2020 05:01:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E77B520656 for ; Wed, 15 Apr 2020 05:01:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cmpxchg-org.20150623.gappssmtp.com header.i=@cmpxchg-org.20150623.gappssmtp.com header.b="Tcxzc6xC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393213AbgDOFBV (ORCPT ); Wed, 15 Apr 2020 01:01:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2393189AbgDOFBL (ORCPT ); Wed, 15 Apr 2020 01:01:11 -0400 Received: from mail-qv1-xf42.google.com (mail-qv1-xf42.google.com [IPv6:2607:f8b0:4864:20::f42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F7A3C0610D6 for ; Tue, 14 Apr 2020 22:01:09 -0700 (PDT) Received: by mail-qv1-xf42.google.com with SMTP id s3so1075361qvk.12 for ; Tue, 14 Apr 2020 22:01:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=ef3HLI/XX5ogd42JRuoGnEbb/Ln3ZxgvuLj5jaeUWkI=; b=Tcxzc6xC3iVTZShTUf3CIv3N8B5ZyCbru12fLV5+tpVooL5/Bo3MM2R4w1+y/qKNnw 9lu0zJBRs+VK1Bc14YzwiZC+K/efs95VT8GzxaoJoz3t2WhfDZxWX+BgsMNU20r8wRPv WS98QN/V8NZIzymtO0juNqdA9Tg6/2OTyjU7Zm1KL9ejebzf7wo1d0uOEsRrlg17M8fg qYmffi6H6MwGLJe4epZjwPPvjWIdIXS0xtejpuhYYUqQSrz2GfoywvJh6tC6sCJVyKe7 xzOQhWdIv/o82YQJCk9DtMPUw2B8iLWuNwugd4l1OepDEbLixuOHRPHRALsrInJO+Rsn o1og== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=ef3HLI/XX5ogd42JRuoGnEbb/Ln3ZxgvuLj5jaeUWkI=; b=r33mv1tef9uKGPgdhUGPGNP36tk4w+eAwRQ+0VklgV4hsxxb3emYvKR5LOg73mh9wG R/rie7as/w2sLhRg2HY8edb3QJ654TpNW/85yuNa2OnvdJ9dTng5rlmQkqyBAgz2xYzt rq0w6Zku7a7u1nqtJFeFFPWc7H1F9pSnJvHDwIt70RKr5flzw6jEDBc6V6SJFYFIdyVB 4yplUMSWJRW0ocuiKA/fLQfclQEjOKK+a9EeP4pa2Mfw1iDis5Pbd1LE78+LIh2NHM7i 4E3hPtBoxPoIxy/3ptJMvElayOwsMx9jAQFt4zVQonT6SMZcbfIfkt3S4hx6oWHLDmve cYnA== X-Gm-Message-State: AGi0PuYhE+aYdnSt8mYPNZwci7wkiJSf9rKEAVTu/DiqIqL7pztdp+3q zPJ3Q6bf4ZEcFejPbjz9l3XXSw== X-Google-Smtp-Source: APiQypJRjg+PyUSZjrIkjpxdMfgyPb9bMEWnffTFRMxoE1aQMUITXzNurR0P/0BN6q0H0W5xTyhSBA== X-Received: by 2002:a0c:e88d:: with SMTP id b13mr3243342qvo.245.1586926868219; Tue, 14 Apr 2020 22:01:08 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::e623]) by smtp.gmail.com with ESMTPSA id 10sm6168833qtp.4.2020.04.14.22.01.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Apr 2020 22:01:07 -0700 (PDT) Date: Wed, 15 Apr 2020 01:01:06 -0400 From: Johannes Weiner To: Waiman Long Cc: Andrew Morton , David Howells , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , Linus Torvalds , Joe Perches , Matthew Wilcox , David Rientjes , 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 Subject: Re: [PATCH 1/2] mm, treewide: Rename kzfree() to kfree_sensitive() Message-ID: <20200415050106.GA154671@cmpxchg.org> References: <20200413211550.8307-1-longman@redhat.com> <20200413211550.8307-2-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200413211550.8307-2-longman@redhat.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 13, 2020 at 05:15:49PM -0400, Waiman Long wrote: > As said by Linus: > > A symmetric naming is only helpful if it implies symmetries in use. > Otherwise it's actively misleading. As the btrfs example proves - people can be tempted by this false symmetry to pair kzalloc with kzfree, which isn't what we wanted. > In "kzalloc()", the z is meaningful and an important part of what the > caller wants. > > In "kzfree()", the z is actively detrimental, because maybe in the > future we really _might_ want to use that "memfill(0xdeadbeef)" or > something. The "zero" part of the interface isn't even _relevant_. > > The main reason that kzfree() exists is to clear sensitive information > that should not be leaked to other future users of the same memory > objects. > > Rename kzfree() to kfree_sensitive() to follow the example of the > recently added kvfree_sensitive() and make the intention of the API > more explicit. In addition, memzero_explicit() is used to clear the > memory to make sure that it won't get optimized away by the compiler. > > The renaming is done by using the command sequence: > > git grep -w --name-only kzfree |\ > xargs sed -i 's/\bkzfree\b/kfree_sensitive/' > > followed by some editing of the kfree_sensitive() kerneldoc and the > use of memzero_explicit() instead of memset(). > > Suggested-by: Joe Perches > Signed-off-by: Waiman Long Looks good to me. Thanks for fixing this very old mistake. Acked-by: Johannes Weiner