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 53ECCC433EF for ; Fri, 28 Jan 2022 10:17:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346783AbiA1KRr (ORCPT ); Fri, 28 Jan 2022 05:17:47 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:39448 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346361AbiA1KRe (ORCPT ); Fri, 28 Jan 2022 05:17:34 -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 ams.source.kernel.org (Postfix) with ESMTPS id 9139CB82510; Fri, 28 Jan 2022 10:17:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B666EC340E0; Fri, 28 Jan 2022 10:17:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643365052; bh=7IY9KOWgCR5BpPK5LveSg3llEn4MIOAt9my1ok1ECak=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=U0HtHGTZC61bd/7Hw2gWVVmvQPPSgIB3+eBK+N2dduFmUcu1uXGcwGDmD9aUxi1Xh wmYvSR4j+Kt6ZUplujn/2qy6AQvONxXUGqKx5LyCqNSDk51iEkPJRFKjXS+08pOcUS dQv2v5ggzRH8atl8I2H97Lksrp6hZWAqgUyNUoZw= Date: Fri, 28 Jan 2022 11:17:24 +0100 From: Greg KH To: Zhou Qingyang Cc: kjlu@umn.edu, Mauro Carvalho Chehab , Hans Verkuil , Tasos Sahanidis , Yang Yingliang , Christophe JAILLET , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] media: saa7134: Fix a NULL pointer dereference in saa7134_initdev() Message-ID: References: <20220124171931.62174-1-zhou1615@umn.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220124171931.62174-1-zhou1615@umn.edu> Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Tue, Jan 25, 2022 at 01:19:30AM +0800, Zhou Qingyang wrote: > In saa7134_initdev(), the return value of vdev_init() is assigned to > dev->video_dev and there is a dereference of it after that. The return > value of vdev_init() will be NULL on the failure allocation, which could > lead to 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: a9622391acb ("V4L/DVB (6792): Fix VBI support") > 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/saa7134/saa7134-core.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/media/pci/saa7134/saa7134-core.c b/drivers/media/pci/saa7134/saa7134-core.c > index 96328b0af164..0de0b00540b6 100644 > --- a/drivers/media/pci/saa7134/saa7134-core.c > +++ b/drivers/media/pci/saa7134/saa7134-core.c > @@ -1202,6 +1202,11 @@ static int saa7134_initdev(struct pci_dev *pci_dev, > pr_info("%s: Overlay support disabled.\n", dev->name); > > dev->video_dev = vdev_init(dev,&saa7134_video_template,"video"); > + if (!dev->video_dev) { > + err = -ENOMEM; > + goto err_unregister_video; > + } > + > dev->video_dev->ctrl_handler = &dev->ctrl_handler; > dev->video_dev->lock = &dev->lock; > dev->video_dev->queue = &dev->video_vbq; > @@ -1224,6 +1229,11 @@ static int saa7134_initdev(struct pci_dev *pci_dev, > dev->name, video_device_node_name(dev->video_dev)); > > dev->vbi_dev = vdev_init(dev, &saa7134_video_template, "vbi"); > + if (!dev->vbi_dev) { > + err = -ENOMEM; > + goto err_unregister_video; > + } > + > dev->vbi_dev->ctrl_handler = &dev->ctrl_handler; > dev->vbi_dev->lock = &dev->lock; > dev->vbi_dev->queue = &dev->vbi_vbq; > -- > 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.