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,UNPARSEABLE_RELAY, 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 E202AC43381 for ; Fri, 15 Feb 2019 15:52:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B97C02192D for ; Fri, 15 Feb 2019 15:52:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388540AbfBOPw0 (ORCPT ); Fri, 15 Feb 2019 10:52:26 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:57824 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732387AbfBOPwZ (ORCPT ); Fri, 15 Feb 2019 10:52:25 -0500 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: ezequiel) with ESMTPSA id 5823D273041 Message-ID: <672eb573c6da3c509b8e0bbc074fff0de58b326f.camel@collabora.com> Subject: Re: [PATCH 1/1] v4l: ioctl: Validate num_planes before using it From: Ezequiel Garcia To: Sakari Ailus , linux-media@vger.kernel.org, hverkuil@xs4all.nl Cc: Thierry Reding Date: Fri, 15 Feb 2019 12:52:14 -0300 In-Reply-To: <20190110124319.22230-1-sakari.ailus@linux.intel.com> References: <20190110124319.22230-1-sakari.ailus@linux.intel.com> Organization: Collabora Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.30.5-1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org 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? [1] https://www.kernel.org/doc/html/latest/media/uapi/v4l/vidioc-g-fmt.html Regards, Eze