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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4EA6FC32771 for ; Tue, 27 Sep 2022 01:12:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229680AbiI0BM5 (ORCPT ); Mon, 26 Sep 2022 21:12:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229604AbiI0BM5 (ORCPT ); Mon, 26 Sep 2022 21:12:57 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 06F849B872; Mon, 26 Sep 2022 18:12:55 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 30E0ACE13E7; Tue, 27 Sep 2022 01:12:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED2CBC433C1; Tue, 27 Sep 2022 01:12:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1664241172; bh=LkKSel0RdldqvXm8rwrJJuPghKrZg2g8e51qKRvCa9k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ikeX8zDYwKANctxavY3Xo8m9v4ulsS7NLH6QPpipbfZnVOBKLejB7PZtHoNvc2GU9 3Fg79+ZbcF6jJCl2fIbNXxvnMXemfCUWaFzZmCqqmuHwRynROEbBMBdAnK+/N7pJ9b Yc7EhieMbTSzsbAspIizPiXXTbifuyzDK+kCmsWzA0S84at0ocXTM6VHHNRpaIJzRA YLj6roYKVcvTTde9IEF+WmeBR7qmcealnWrwGzpQ75gi0/b3ADzcZW/mwlxhpMBzjh ItIL6Sx4f86ssi9SO+nQ4a/ghKbHpt0Y0X596DXbfSE/UTXXlVVosYVPHkoZ25m0kC Gd1mH+kraml8A== Date: Mon, 26 Sep 2022 20:12:46 -0500 From: "Gustavo A. R. Silva" To: Kees Cook Cc: Maximilian Luz , Hans de Goede , Mark Gross , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH] platform/surface: Split memcpy() of struct ssam_event flexible array Message-ID: References: <20220927004011.1942739-1-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220927004011.1942739-1-keescook@chromium.org> Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org On Mon, Sep 26, 2022 at 05:40:11PM -0700, Kees Cook wrote: > To work around a misbehavior of the compiler's ability to see into > composite flexible array structs (as detailed in the coming memcpy() > hardening series[1]), split the memcpy() of the header and the payload > so no false positive run-time overflow warning will be generated. > > [1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@chromium.org > > Cc: Maximilian Luz > Cc: Hans de Goede > Cc: Mark Gross > Cc: platform-driver-x86@vger.kernel.org > Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva Thanks! -- Gustavo > --- > drivers/platform/surface/surface_acpi_notify.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/platform/surface/surface_acpi_notify.c b/drivers/platform/surface/surface_acpi_notify.c > index 44e317970557..50500e562963 100644 > --- a/drivers/platform/surface/surface_acpi_notify.c > +++ b/drivers/platform/surface/surface_acpi_notify.c > @@ -355,7 +355,8 @@ static u32 san_evt_bat_nf(struct ssam_event_notifier *nf, > INIT_DELAYED_WORK(&work->work, san_evt_bat_workfn); > work->dev = d->dev; > > - memcpy(&work->event, event, sizeof(struct ssam_event) + event->length); > + work->event = *event; > + memcpy(work->event.data, event->data, event->length); > > queue_delayed_work(san_wq, &work->work, delay); > return SSAM_NOTIF_HANDLED; > -- > 2.34.1 >