From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=9l+J=37=vger.kernel.org=linux-usb-owner@kernel.org>
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=-13.3 required=3.0
	tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,
	MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,
	USER_AGENT_SANE_2 autolearn=unavailable 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 3008CC352A3
	for <linux-usb@archiver.kernel.org>; Tue, 11 Feb 2020 14:31:41 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [209.132.180.67])
	by mail.kernel.org (Postfix) with ESMTP id 1280120873
	for <linux-usb@archiver.kernel.org>; Tue, 11 Feb 2020 14:31:41 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1729643AbgBKObh (ORCPT <rfc822;linux-usb@archiver.kernel.org>);
        Tue, 11 Feb 2020 09:31:37 -0500
Received: from mx2.suse.de ([195.135.220.15]:36808 "EHLO mx2.suse.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1728339AbgBKObh (ORCPT <rfc822;linux-usb@vger.kernel.org>);
        Tue, 11 Feb 2020 09:31:37 -0500
X-Virus-Scanned: by amavisd-new at test-mx.suse.de
Received: from relay2.suse.de (unknown [195.135.220.254])
        by mx2.suse.de (Postfix) with ESMTP id 9ED59C075;
        Tue, 11 Feb 2020 14:31:34 +0000 (UTC)
Message-ID: <1581431490.1580.6.camel@suse.de>
Subject: Re: KASAN: use-after-free Read in uvc_probe
From:   Oliver Neukum <oneukum@suse.de>
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     syzbot <syzbot+9a48339b077c5a80b869@syzkaller.appspotmail.com>,
        andreyknvl@google.com, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org, linux-usb@vger.kernel.org,
        mchehab@kernel.org, syzkaller-bugs@googlegroups.com
Date:   Tue, 11 Feb 2020 15:31:30 +0100
In-Reply-To: <20200210141812.GB4727@pendragon.ideasonboard.com>
References: <000000000000780999059c048dfc@google.com>
         <1581344006.26936.7.camel@suse.de>
         <20200210141812.GB4727@pendragon.ideasonboard.com>
Content-Type: text/plain; charset="UTF-8"
X-Mailer: Evolution 3.26.6 
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-usb-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-usb.vger.kernel.org>
X-Mailing-List: linux-usb@vger.kernel.org

Am Montag, den 10.02.2020, 16:18 +0200 schrieb Laurent Pinchart:
> Hi Oliver,
> 
> Thank you for the patch.
> 
> On Mon, Feb 10, 2020 at 03:13:26PM +0100, Oliver Neukum wrote:
> > Am Montag, den 13.01.2020, 04:24 -0800 schrieb syzbot:
> > > Hello,
> > > 
> > > syzbot found the following crash on:
> > > 
> > > HEAD commit:    ae179410 usb: gadget: add raw-gadget interface
> > > git tree:       https://github.com/google/kasan.git usb-fuzzer
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=132223fee00000
> > > kernel config:  https://syzkaller.appspot.com/x/.config?x=ad1d751a3a72ae57
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=9a48339b077c5a80b869
> > > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16857325e00000
> > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=142e069ee00000
> > > 
> > > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > > Reported-by: syzbot+9a48339b077c5a80b869@syzkaller.appspotmail.com
> > > 
> > > usb 1-1: New USB device found, idVendor=0bd3, idProduct=0555,  
> > > bcdDevice=69.6a
> > > usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
> > > usb 1-1: config 0 descriptor??
> > > usb 1-1: string descriptor 0 read error: -71
> > > uvcvideo: Found UVC 0.00 device <unnamed> (0bd3:0555)
> > > ==================================================================
> > > BUG: KASAN: use-after-free in uvc_register_terms  
> > > drivers/media/usb/uvc/uvc_driver.c:2038 [inline]
> > > BUG: KASAN: use-after-free in uvc_register_chains  
> > > drivers/media/usb/uvc/uvc_driver.c:2070 [inline]
> > > BUG: KASAN: use-after-free in uvc_probe.cold+0x2193/0x29de  
> > > drivers/media/usb/uvc/uvc_driver.c:2201
> > > Read of size 2 at addr ffff8881d4f1bc2e by task kworker/1:2/94
> > 
> > #syz test: https://github.com/google/kasan.git ae179410
> > 
> > From db844641a5e30f3cfc0ce9cde156b3cc356b6c0c Mon Sep 17 00:00:00 2001
> > From: Oliver Neukum <oneukum@suse.com>
> > Date: Mon, 10 Feb 2020 15:10:36 +0100
> > Subject: [PATCH] UVC: deal with unnamed streams
> > 
> > The pointer can be NULL
> > 
> > Signed-off-by: Oliver Neukum <oneukum@suse.com>
> > ---
> >  drivers/media/usb/uvc/uvc_driver.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> > index 99883550375e..26558a89f2fe 100644
> > --- a/drivers/media/usb/uvc/uvc_driver.c
> > +++ b/drivers/media/usb/uvc/uvc_driver.c
> > @@ -2069,7 +2069,8 @@ static int uvc_register_terms(struct uvc_device *dev,
> >  		stream = uvc_stream_by_id(dev, term->id);
> >  		if (stream == NULL) {
> >  			uvc_printk(KERN_INFO, "No streaming interface found "
> > -				   "for terminal %u.", term->id);
> > +				   "for terminal %u.",
> > +				   term->id ? term->id : "(Unnamed)");
> 
> Have you tried compiling this ?

Yes. It does compile. Why?

	Regards
		Oliver