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 E68A2C433EF for ; Wed, 15 Dec 2021 21:59:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230289AbhLOV70 (ORCPT ); Wed, 15 Dec 2021 16:59:26 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:58334 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230116AbhLOV7Z (ORCPT ); Wed, 15 Dec 2021 16:59:25 -0500 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 dfw.source.kernel.org (Postfix) with ESMTPS id 3BC0861ADD; Wed, 15 Dec 2021 21:59:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B94AC36AE2; Wed, 15 Dec 2021 21:59:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1639605564; bh=DVg54QbMWu+0DdObQKJN9dF5Q1puv+DkorrIi0OFPFw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VZkjPXSi+PKmQfTY3OXjEFGlXW2uD/kzBLrimazVJbPzcfud+jl81BX41iCcMEd8s cVR8upjEpWY577HmriQTkSCzTyR5DPqJFW6+h0xGRMa0jhXa+egPUl44MkKcUUuYMp oHZ4bZJgFgy+I1zPjCynd7G2J/GneX5J+SvysYv4rfVDmaZHWZYF3lg8wCZcmNSfBz +6TQScSMXyclEt318c9dWMBNkHxov8H43aFqm5eB7mqd7ovh7/5kAR/V0EWGUEvz/n ucpIZOe7c1pcX8DaI4R4Xx8Q5cL8M1P+WdGJGs50NTmu9j7izUvksfr1cEeugES6CI mvrp+V7gD5sRw== Date: Wed, 15 Dec 2021 16:05:05 -0600 From: "Gustavo A. R. Silva" To: Kees Cook Cc: Laurent Pinchart , Mauro Carvalho Chehab , Arnd Bergmann , Sakari Ailus , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH] media: omap3isp: Use struct_group() for memcpy() region Message-ID: <20211215220505.GB21862@embeddedor> References: <20211118184352.1284792-1-keescook@chromium.org> <20211213232416.GA60133@embeddedor> <202112150937.8E4974D35@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202112150937.8E4974D35@keescook> Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org On Wed, Dec 15, 2021 at 09:38:55AM -0800, Kees Cook wrote: > On Mon, Dec 13, 2021 at 05:24:16PM -0600, Gustavo A. R. Silva wrote: > > On Thu, Nov 18, 2021 at 10:43:52AM -0800, Kees Cook wrote: > > > In preparation for FORTIFY_SOURCE performing compile-time and run-time > > > field bounds checking for memcpy(), memmove(), and memset(), avoid > > > intentionally writing across neighboring fields. Wrap the target region > > > in struct_group(). This additionally fixes a theoretical misalignment > > > of the copy (since the size of "buf" changes between 64-bit and 32-bit, > > > but this is likely never built for 64-bit). > > > > > > FWIW, I think this code is totally broken on 64-bit (which appears to > > > not be a "real" build configuration): it would either always fail (with > > > an uninitialized data->buf_size) or would cause corruption in userspace > > > due to the copy_to_user() in the call path against an uninitialized > > > data->buf value: > > > > > > omap3isp_stat_request_statistics_time32(...) > > > struct omap3isp_stat_data data64; > > > ... > > > omap3isp_stat_request_statistics(stat, &data64); > > > > > > int omap3isp_stat_request_statistics(struct ispstat *stat, > > > struct omap3isp_stat_data *data) > > > ... > > > buf = isp_stat_buf_get(stat, data); > > > > > > static struct ispstat_buffer *isp_stat_buf_get(struct ispstat *stat, > > > struct omap3isp_stat_data *data) > > > ... > > > if (buf->buf_size > data->buf_size) { > > > ... > > > return ERR_PTR(-EINVAL); > > > } > > > ... > > > rval = copy_to_user(data->buf, > > > buf->virt_addr, > > > buf->buf_size); > > > > > > Regardless, additionally initialize data64 to be zero-filled to avoid > > > undefined behavior. > > > > > > Fixes: 378e3f81cb56 ("media: omap3isp: support 64-bit version of omap3isp_stat_data") > > > Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva > > > --- > > > drivers/media/platform/omap3isp/ispstat.c | 5 +++-- > > > include/uapi/linux/omap3isp.h | 21 +++++++++++++-------- > > > 2 files changed, 16 insertions(+), 10 deletions(-) > > > > > > diff --git a/drivers/media/platform/omap3isp/ispstat.c b/drivers/media/platform/omap3isp/ispstat.c > > > index 5b9b57f4d9bf..68cf68dbcace 100644 > > > --- a/drivers/media/platform/omap3isp/ispstat.c > > > +++ b/drivers/media/platform/omap3isp/ispstat.c > > > @@ -512,7 +512,7 @@ int omap3isp_stat_request_statistics(struct ispstat *stat, > > > int omap3isp_stat_request_statistics_time32(struct ispstat *stat, > > > struct omap3isp_stat_data_time32 *data) > > > { > > > - struct omap3isp_stat_data data64; > > > + struct omap3isp_stat_data data64 = { }; > > > int ret; > > > > > > ret = omap3isp_stat_request_statistics(stat, &data64); > > > @@ -521,7 +521,8 @@ int omap3isp_stat_request_statistics_time32(struct ispstat *stat, > > > > > > data->ts.tv_sec = data64.ts.tv_sec; > > > data->ts.tv_usec = data64.ts.tv_usec; > > > - memcpy(&data->buf, &data64.buf, sizeof(*data) - sizeof(data->ts)); > > > + data->buf = (uintptr_t)data64.buf; > > > > Shouldn't this be > > > > data->buf = (uintptr_t)(void *)data64.buf; > > > > instead? > > This is already a void *: > > struct omap3isp_stat_data { > ... > void __user *buf; > }; > > But I agree, the mix of structures in here is confusing! :) Yep; you're right. :) Thanks -- Gustavo