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=-13.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 DC514C432C1 for ; Wed, 25 Sep 2019 04:35:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A449E20665 for ; Wed, 25 Sep 2019 04:35:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730570AbfIYEfi (ORCPT ); Wed, 25 Sep 2019 00:35:38 -0400 Received: from mga18.intel.com ([134.134.136.126]:42543 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725784AbfIYEfi (ORCPT ); Wed, 25 Sep 2019 00:35:38 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Sep 2019 21:35:37 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,546,1559545200"; d="scan'208";a="203528751" Received: from pktinlab.iind.intel.com (HELO pktinlab) ([10.66.253.121]) by fmsmga001.fm.intel.com with ESMTP; 24 Sep 2019 21:35:35 -0700 Date: Wed, 25 Sep 2019 09:59:18 +0530 From: "Bharadiya,Pankaj" To: Kees Cook Cc: pankaj.bharadiya@gmail.com, andriy.shevchenko@linux.intel.com, kernel-hardening@lists.openwall.com, akpm@linux-foundation.org, mayhs11saini@gmail.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/5] linux/kernel.h: Add sizeof_member macro Message-ID: <20190925042917.GA83131@pktinlab> References: <20190924105839.110713-1-pankaj.laxminarayan.bharadiya@intel.com> <20190924105839.110713-2-pankaj.laxminarayan.bharadiya@intel.com> <201909240920.AE3CD67E87@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201909240920.AE3CD67E87@keescook> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 24, 2019 at 09:22:10AM -0700, Kees Cook wrote: > On Tue, Sep 24, 2019 at 04:28:35PM +0530, Pankaj Bharadiya wrote: > > At present we have 3 different macros to calculate the size of a > > member of a struct: > > - SIZEOF_FIELD > > - FIELD_SIZEOF > > - sizeof_field > > > > To bring uniformity in entire kernel source tree let's add > > sizeof_member macro. > > > > Replace all occurrences of above 3 macro's with sizeof_member in > > future patches. > > > > Signed-off-by: Pankaj Bharadiya > > --- > > include/linux/kernel.h | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > Since stddef.h ends up needing this macro, and kernel.h includes > stddef.h, why not put this macro in stddef.h instead? Then the > open-coded version of it in stddef (your last patch) can use > sizeof_member()? > If I understood correctly, Andrew suggested to add such macros in kernel.h https://www.openwall.com/lists/kernel-hardening/2019/06/11/5 Moreover similar type of other macros (like typeof_member & ARRAY_SIZE) are defined in kernel.h But as you pointed out, looks like stddef.h is the right place for this macro. > Otherwise, yes, looks good. (Though I might re-order the patches so the > last patch is the tree-wide swap -- then you don't need the exclusions, > I think?) > I went through your tree. https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/log/?h=kspp/sizeof_member/full Thank you for reordering the patches. Thanks, Pankaj > -Kees > > > > > diff --git a/include/linux/kernel.h b/include/linux/kernel.h > > index 4fa360a13c1e..0b80d8bb3978 100644 > > --- a/include/linux/kernel.h > > +++ b/include/linux/kernel.h > > @@ -79,6 +79,15 @@ > > */ > > #define round_down(x, y) ((x) & ~__round_mask(x, y)) > > > > +/** > > + * sizeof_member - get the size of a struct's member > > + * @T: the target struct > > + * @m: the target struct's member > > + * Return: the size of @m in the struct definition without having a > > + * declared instance of @T. > > + */ > > +#define sizeof_member(T, m) (sizeof(((T *)0)->m)) > > + > > /** > > * FIELD_SIZEOF - get the size of a struct's field > > * @t: the target struct > > -- > > 2.17.1 > > > > -- > Kees Cook