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 1B930C433EF for ; Fri, 28 Jan 2022 10:17:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347554AbiA1KRi (ORCPT ); Fri, 28 Jan 2022 05:17:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40210 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347746AbiA1KRP (ORCPT ); Fri, 28 Jan 2022 05:17:15 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 42D14C06175A; Fri, 28 Jan 2022 02:17:15 -0800 (PST) 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 D7A8C61E3B; Fri, 28 Jan 2022 10:17:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96C1BC340E0; Fri, 28 Jan 2022 10:17:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643365034; bh=qSscwoImkGW0Lgs8qkgO5CPtEC7NcVAPM0YCkJG5tks=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nMf6LQMsdbPQwLHYf/mz9/220V0ACYO8PS2k4k7LpNmIifCvRqmvAfI9aLp58hXTU +nhTs8M4d+R0BAIL9E951ozxZHYZlHZU51sMoHJKISBPH3i1EHkNO9ZQxM+BPryY9h tl030WiTJSlTJvp14ukIXhEbUvLIejjhKqFQhB2M= Date: Fri, 28 Jan 2022 11:17:11 +0100 From: Greg KH To: Zhou Qingyang Cc: kjlu@umn.edu, Mauro Carvalho Chehab , Hans Verkuil , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] media: pci: cx23855-video.c: Fix a NULL pointer dereference in cx23885_video_register() Message-ID: References: <20220124171620.61466-1-zhou1615@umn.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220124171620.61466-1-zhou1615@umn.edu> Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Tue, Jan 25, 2022 at 01:16:18AM +0800, Zhou Qingyang wrote: > In cx23885_video_register(), the return value of cx23885_vdev_init() is > assigned to dev->video_dev and there is a dereference of it after that. > the return value of cx23885_vdev_init() could be NULL on failure of > allocation, which could lead to a NULL pointer dereference. > > the same as dev->vbi_dev. > > Fix this bug by adding a NULL check of dev->video_dev and dev->vbi_dev. > > This bug was found by a static analyzer. > > Builds with 'make allyesconfig' show no new warnings, > and our static analyzer no longer warns about this code. > > Fixes: 453afdd9ce33 ("[media] cx23885: convert to vb2") > Signed-off-by: Zhou Qingyang > --- > The analysis employs differential checking to identify inconsistent > security operations (e.g., checks or kfrees) between two code paths > and confirms that the inconsistent operations are not recovered in the > current function or the callers, so they constitute bugs. > > Note that, as a bug found by static analysis, it can be a false > positive or hard to trigger. Multiple researchers have cross-reviewed > the bug. > > drivers/media/pci/cx23885/cx23885-video.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/media/pci/cx23885/cx23885-video.c b/drivers/media/pci/cx23885/cx23885-video.c > index a380e0920a21..1b95109eff8c 100644 > --- a/drivers/media/pci/cx23885/cx23885-video.c > +++ b/drivers/media/pci/cx23885/cx23885-video.c > @@ -1353,6 +1353,11 @@ int cx23885_video_register(struct cx23885_dev *dev) > /* register Video device */ > dev->video_dev = cx23885_vdev_init(dev, dev->pci, > &cx23885_video_template, "video"); > + if (!dev->video_dev) { > + err = -ENOMEM; > + goto fail_unreg; > + } > + > dev->video_dev->queue = &dev->vb2_vidq; > dev->video_dev->device_caps = V4L2_CAP_READWRITE | V4L2_CAP_STREAMING | > V4L2_CAP_AUDIO | V4L2_CAP_VIDEO_CAPTURE; > @@ -1381,6 +1386,11 @@ int cx23885_video_register(struct cx23885_dev *dev) > /* register VBI device */ > dev->vbi_dev = cx23885_vdev_init(dev, dev->pci, > &cx23885_vbi_template, "vbi"); > + if (!dev->vbi_dev) { > + err = -ENOMEM; > + goto fail_unreg; > + } > + > dev->vbi_dev->queue = &dev->vb2_vbiq; > dev->vbi_dev->device_caps = V4L2_CAP_READWRITE | V4L2_CAP_STREAMING | > V4L2_CAP_AUDIO | V4L2_CAP_VBI_CAPTURE; > -- > 2.25.1 > As stated before, umn.edu is still not allowed to contribute to the Linux kernel. Please work with your administration to resolve this issue.