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 EAEDBC433F5 for ; Fri, 28 Jan 2022 10:17:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347718AbiA1KRN (ORCPT ); Fri, 28 Jan 2022 05:17:13 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:39134 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345222AbiA1KQz (ORCPT ); Fri, 28 Jan 2022 05:16:55 -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 10DAEB8250F; Fri, 28 Jan 2022 10:16:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B971C340EB; Fri, 28 Jan 2022 10:16:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643365012; bh=L1Ekx2OO3TF2p45CkBw+hlZqHckVYlcP5aDSAh4JfqE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fHCFDZxMW561/OdD+iu0QHkKIw1maK5XNk2YsZ1PqmE8GRcF6AWxmMGJL1QQu3SC/ OVn7QpMRevsvNvWhvVcUZbjDsimxOCK+P+Q8zZJ/sIYW+H8SsFjxllLXIdmee1HPJd XkHLppmUxniry02AbQDgK/oLPj+VMc8B4fmiL5i8= Date: Fri, 28 Jan 2022 11:16:49 +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: media/pci: Fix a NULL pointer dereference in cx23885_417_register() Message-ID: References: <20220124170611.58864-1-zhou1615@umn.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220124170611.58864-1-zhou1615@umn.edu> Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Tue, Jan 25, 2022 at 01:06:10AM +0800, Zhou Qingyang wrote: > In cx23885_417_register(), the return value of cx23885_video_dev_alloc() > is assigned to dev->v4l_device() and there is a dereference of it after > that. the return value of cx23885_video_dev_alloc() could be NULL on > failure of allocation, which could lead to a NULL pointer dereference. > > Fix this bug by adding a NULL check of dev->v4l_device. > > 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/cx23885-417.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/media/pci/cx23885/cx23885-417.c b/drivers/media/pci/cx23885/cx23885-417.c > index 434677bd4ad1..fcc9c1117ed1 100644 > --- a/drivers/media/pci/cx23885/cx23885-417.c > +++ b/drivers/media/pci/cx23885/cx23885-417.c > @@ -1521,6 +1521,8 @@ int cx23885_417_register(struct cx23885_dev *dev) > /* Allocate and initialize V4L video device */ > dev->v4l_device = cx23885_video_dev_alloc(tsport, > dev->pci, &cx23885_mpeg_template, "mpeg"); > + if (!dev->v4l_device) > + return -ENOMEM; > q = &dev->vb2_mpegq; > q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE; > q->io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF | VB2_READ; > -- > 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.