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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 C8304C43381 for ; Fri, 15 Feb 2019 16:05:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A0B2221927 for ; Fri, 15 Feb 2019 16:05:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387995AbfBOQFr (ORCPT ); Fri, 15 Feb 2019 11:05:47 -0500 Received: from lb3-smtp-cloud8.xs4all.net ([194.109.24.29]:47591 "EHLO lb3-smtp-cloud8.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726213AbfBOQFr (ORCPT ); Fri, 15 Feb 2019 11:05:47 -0500 Received: from [192.168.2.10] ([212.251.195.8]) by smtp-cloud8.xs4all.net with ESMTPA id ufzhgKflF4HFnufzkgtrHv; Fri, 15 Feb 2019 17:05:45 +0100 Subject: Re: [PATCH 1/1] v4l: ioctl: Validate num_planes before using it To: Ezequiel Garcia , Sakari Ailus , linux-media@vger.kernel.org Cc: Thierry Reding References: <20190110124319.22230-1-sakari.ailus@linux.intel.com> <672eb573c6da3c509b8e0bbc074fff0de58b326f.camel@collabora.com> From: Hans Verkuil Message-ID: <0639565e-7b3c-5917-3475-dc83a676760f@xs4all.nl> Date: Fri, 15 Feb 2019 17:05:41 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <672eb573c6da3c509b8e0bbc074fff0de58b326f.camel@collabora.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-CMAE-Envelope: MS4wfAJsp8nR5kI7PGMWntbxAJ+ubXqNd5b9gMrxMZv3Vh7yMYkLeUf9sa8OihVleHIhApoWhRHdMAZlxqiJo0pqOZqBpXwa5uFtDCDazTRxiRn/BKI8fl5Q 4+H6aE/wZw+Cgo/Zsi4AMUs20/5pTNqLeIhh/dCw6/b/COgWWlRembSWHMzUFJF9p1NxtFaatwMoJT6WY3YOhOElQ5PbPYpKicJHcObClYf9UWpsSwRh8Ia0 R3rd9CdKc9VrTlqgS29lO48OXiRjH4UiuoYSaIOc8TZpVOqwGx8H9FUGgITYxYjo Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On 2/15/19 4:52 PM, Ezequiel Garcia wrote: > On Thu, 2019-01-10 at 14:43 +0200, Sakari Ailus wrote: >> The for loop to reset the memory of the plane reserved fields runs over >> num_planes provided by the user without validating it. Ensure num_planes >> is no more than VIDEO_MAX_PLANES before the loop. >> >> Fixes: 4e1e0eb0e074 ("media: v4l2-ioctl: Zero v4l2_plane_pix_format reserved fields") >> Signed-off-by: Sakari Ailus >> --- >> Hi folks, >> >> This patch goes on top of Thierry's patch "media: v4l2-ioctl: Clear only >> per-plane reserved fields". >> >> drivers/media/v4l2-core/v4l2-ioctl.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c >> index 392f1228af7b5..9e68a608ac6d3 100644 >> --- a/drivers/media/v4l2-core/v4l2-ioctl.c >> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c >> @@ -1551,6 +1551,8 @@ static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops, >> if (unlikely(!ops->vidioc_s_fmt_vid_cap_mplane)) >> break; >> CLEAR_AFTER_FIELD(p, fmt.pix_mp.xfer_func); >> + if (p->fmt.pix_mp.num_planes > VIDEO_MAX_PLANES) >> + break; >> for (i = 0; i < p->fmt.pix_mp.num_planes; i++) >> CLEAR_AFTER_FIELD(&p->fmt.pix_mp.plane_fmt[i], bytesperline); >> return ops->vidioc_s_fmt_vid_cap_mplane(file, fh, arg); >> @@ -1581,6 +1583,8 @@ static int v4l_s_fmt(const struct v4l2_ioctl_ops *ops, >> if (unlikely(!ops->vidioc_s_fmt_vid_out_mplane)) >> break; >> CLEAR_AFTER_FIELD(p, fmt.pix_mp.xfer_func); >> + if (p->fmt.pix_mp.num_planes > VIDEO_MAX_PLANES) >> + break; >> for (i = 0; i < p->fmt.pix_mp.num_planes; i++) >> CLEAR_AFTER_FIELD(&p->fmt.pix_mp.plane_fmt[i], bytesperline); >> return ops->vidioc_s_fmt_vid_out_mplane(file, fh, arg); >> @@ -1648,6 +1652,8 @@ static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops, >> if (unlikely(!ops->vidioc_try_fmt_vid_cap_mplane)) >> break; >> CLEAR_AFTER_FIELD(p, fmt.pix_mp.xfer_func); >> + if (p->fmt.pix_mp.num_planes > VIDEO_MAX_PLANES) >> + break; >> for (i = 0; i < p->fmt.pix_mp.num_planes; i++) >> CLEAR_AFTER_FIELD(&p->fmt.pix_mp.plane_fmt[i], bytesperline); >> return ops->vidioc_try_fmt_vid_cap_mplane(file, fh, arg); >> @@ -1678,6 +1684,8 @@ static int v4l_try_fmt(const struct v4l2_ioctl_ops *ops, >> if (unlikely(!ops->vidioc_try_fmt_vid_out_mplane)) >> break; >> CLEAR_AFTER_FIELD(p, fmt.pix_mp.xfer_func); >> + if (p->fmt.pix_mp.num_planes > VIDEO_MAX_PLANES) >> + break; >> for (i = 0; i < p->fmt.pix_mp.num_planes; i++) >> CLEAR_AFTER_FIELD(&p->fmt.pix_mp.plane_fmt[i], bytesperline); >> return ops->vidioc_try_fmt_vid_out_mplane(file, fh, arg); > > I'm under the impression this commit is causing the following v4l2-compliance warning: > > TRY_FMT cannot handle an invalid pixelformat. > This may or may not be a problem. For more information see: > http://www.mail-archive.com/linux-media@vger.kernel.org/msg56550.html > > This applies to try_fmt and s_fmt. > > After checking the v4l2 spec, it seems we can only error on a bad type field [1]: > > "Drivers should not return an error code unless the type field is invalid". > > Perhaps we can clamp num_planes to VIDEO_MAX_PLANES, instead of erroring out? Yes, that would be the right approach. Ezequiel, can you clamp num_planes and test the patch? And post it if it fixes the warning? This really should have been caught by testing with e.g. vivid and v4l2-compliance. Regards, Hans > > [1] https://www.kernel.org/doc/html/latest/media/uapi/v4l/vidioc-g-fmt.html > > Regards, > Eze >