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 X-Spam-Level: X-Spam-Status: No, score=-13.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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_1 autolearn=ham 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 6F693C352A3 for ; Tue, 11 Feb 2020 15:38:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4364D2051A for ; Tue, 11 Feb 2020 15:38:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="IYsHxeuQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729388AbgBKPik (ORCPT ); Tue, 11 Feb 2020 10:38:40 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:48494 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729114AbgBKPik (ORCPT ); Tue, 11 Feb 2020 10:38:40 -0500 Received: from pendragon.ideasonboard.com (81-175-216-236.bb.dnainternet.fi [81.175.216.236]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id A53DA9DA; Tue, 11 Feb 2020 16:38:37 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1581435517; bh=+RyKO39OD+gDnD8NO7nQf/9zFy2ANb076as+KLXHN3A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IYsHxeuQzWZTrOtQJmdoaa5o4IGzHNFH6FHtqVTw7rYFH5hQFxRetS9qf+zJ6eydB 6YrCSiuRZRZ5MqSCKCTD0Yn1ZW58YflBuBXjiA3530rMRe4m/gvSPl0P0a8NVKAlih jNuFfydaEk+QsxdWGcLbOvRE52fGN/imQ+d/xbdo= Date: Tue, 11 Feb 2020 17:38:23 +0200 From: Laurent Pinchart To: Oliver Neukum Cc: syzbot , 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 Subject: Re: KASAN: use-after-free Read in uvc_probe Message-ID: <20200211153823.GD22612@pendragon.ideasonboard.com> References: <000000000000780999059c048dfc@google.com> <1581344006.26936.7.camel@suse.de> <20200210141812.GB4727@pendragon.ideasonboard.com> <1581431490.1580.6.camel@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1581431490.1580.6.camel@suse.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Oliver, On Tue, Feb 11, 2020 at 03:31:30PM +0100, Oliver Neukum wrote: > Am Montag, den 10.02.2020, 16:18 +0200 schrieb Laurent Pinchart: > > 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 (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 > > > 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 > > > --- > > > 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? Because term->id is a u8, "(Unnamed)" is a const char *, and %u requires an integer. I'm surprised the compiler doesn't complain, but in any case, it's not right :-) -- Regards, Laurent Pinchart