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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 BB6F9C433E0 for ; Wed, 17 Jun 2020 16:30:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 98ED9208D5 for ; Wed, 17 Jun 2020 16:30:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="DvAAbM3a" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727004AbgFQQaU (ORCPT ); Wed, 17 Jun 2020 12:30:20 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:32327 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726873AbgFQQaT (ORCPT ); Wed, 17 Jun 2020 12:30:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592411418; 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=1gl38ZIWtqPJzo0qG7cpW4/TOD8j71KgD8Itx/SdC58=; b=DvAAbM3a/BsOk431epaaWOXmRAuh4AJNGAoVjOfOLucTIZeIdYnvoSb6COPEApEs7r+RE3 6vqO17mmH6OFnnZsdru4Plj/wmbiHMmqI1Ba9LWNrqZYor4wRH0Jq8wNq2vluqwV9ud84r vIi2RUYi+l6F1tjT/ZFw6JK5ZYRS3K4= 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-105-TCGmiqeLOzyLqF3Wr-QGiA-1; Wed, 17 Jun 2020 12:30:16 -0400 X-MC-Unique: TCGmiqeLOzyLqF3Wr-QGiA-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 46C9010753F5; Wed, 17 Jun 2020 16:30:09 +0000 (UTC) Received: from localhost (unknown [10.18.25.174]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1C7985C1D4; Wed, 17 Jun 2020 16:30:09 +0000 (UTC) Date: Wed, 17 Jun 2020 12:30:08 -0400 From: Mike Snitzer To: "Gustavo A. R. Silva" Cc: Alasdair Kergon , dm-devel@redhat.com, linux-kernel@vger.kernel.org, Kees Cook Subject: Re: dm ioctl: Use struct_size() helper Message-ID: <20200617163008.GA12083@redhat.com> References: <20190828183825.GA4216@embeddedor> <885e7ea3-b29a-eba0-569e-64760102016e@embeddedor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <885e7ea3-b29a-eba0-569e-64760102016e@embeddedor.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 16 2020 at 6:06pm -0400, Gustavo A. R. Silva wrote: > Hi all, > > Friendly ping: who can take this? > > It's been almost a year... and I just noticed there was a problem > with the email addresses back then... > > I just fixed the issue and this patch should now appear on > dm-devel@redhat.com and LKML. I don't see any resubmit from you on either list. But I've applied the fix by hand and attributed it to you. Thanks, Mike > On 8/28/19 13:38, Gustavo A. R. Silva wrote: > > One of the more common cases of allocation size calculations is finding > > the size of a structure that has a zero-sized array at the end, along > > with memory for some number of elements for that array. For example: > > > > struct dm_target_deps { > > ... > > __u64 dev[0]; /* out */ > > }; > > > > Make use of the struct_size() helper instead of an open-coded version > > in order to avoid any potential type mistakes. > > > > So, replace the following form: > > > > sizeof(*deps) + (sizeof(*deps->dev) * count) > > > > with: > > > > struct_size(deps, dev, count) > > > > This code was detected with the help of Coccinelle. > > > > Signed-off-by: Gustavo A. R. Silva > > --- > > drivers/md/dm-ioctl.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c > > index fb6f8fb1f13d..b2d52cec70d4 100644 > > --- a/drivers/md/dm-ioctl.c > > +++ b/drivers/md/dm-ioctl.c > > @@ -1446,7 +1446,7 @@ static void retrieve_deps(struct dm_table *table, > > /* > > * Check we have enough space. > > */ > > - needed = sizeof(*deps) + (sizeof(*deps->dev) * count); > > + needed = struct_size(deps, dev, count); > > if (len < needed) { > > param->flags |= DM_BUFFER_FULL_FLAG; > > return; > > >