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 1B04BC433F5 for ; Fri, 28 Jan 2022 10:17:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243811AbiA1KRE (ORCPT ); Fri, 28 Jan 2022 05:17:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344262AbiA1KQt (ORCPT ); Fri, 28 Jan 2022 05:16:49 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E3D42C061748; Fri, 28 Jan 2022 02:16:48 -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 ams.source.kernel.org (Postfix) with ESMTPS id AAB12B82515; Fri, 28 Jan 2022 10:16:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB6E0C340E0; Fri, 28 Jan 2022 10:16:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643365006; bh=aXFKQLcOD29T44S1AVz7fr49JBJ8TW2u/0pXBUvdriE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Y/EzRTWPRRDo9rnpTwxgH9Ov8siBFtU/hiXGLTQmD/9Ilseo/Zh5m3NzN0UoSTU3b 5zl+bqcvOkann15pczsI1kqYEamXAUQLzAv2kr2JGuDsoWnJER073lqvZBbBi7gnow s2IPaDuG6WKtqJIapqr1JREI4Fx1W/2fKkd54zN8= Date: Fri, 28 Jan 2022 11:16:43 +0100 From: Greg KH To: Zhou Qingyang Cc: kjlu@umn.edu, Mauro Carvalho Chehab , Zhen Lei , Arnd Bergmann , Hans Verkuil , Michael Schimek , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] media: bttv: Fix a NULL pointer dereference in setup_window_lock() Message-ID: References: <20220124170515.58519-1-zhou1615@umn.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220124170515.58519-1-zhou1615@umn.edu> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 25, 2022 at 01:05:13AM +0800, Zhou Qingyang wrote: > In setup_window_lock(), the return value of videobuf_sg_alloc() is > assigned to variable new and there is a dereference of it after > that. the return value of videobuf_sg_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 new. > > 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: e5bd0260e7d3 ("V4L/DVB (5077): Bttv cropping 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/bt8xx/bttv-driver.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/media/pci/bt8xx/bttv-driver.c b/drivers/media/pci/bt8xx/bttv-driver.c > index 8cc9bec43688..6338f98d845d 100644 > --- a/drivers/media/pci/bt8xx/bttv-driver.c > +++ b/drivers/media/pci/bt8xx/bttv-driver.c > @@ -2182,6 +2182,8 @@ static int setup_window_lock(struct bttv_fh *fh, struct bttv *btv, > struct bttv_buffer *new; > > new = videobuf_sg_alloc(sizeof(*new)); > + if (!new) > + return -ENOMEM; > new->crop = btv->crop[!!fh->do_crop].rect; > bttv_overlay_risc(btv, &fh->ov, fh->ovfmt, new); > retval = bttv_switch_overlay(btv,fh,new); > -- > 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.