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Wed, 15 Jan 2020 18:02:50 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00FHxDgx048148; Wed, 15 Jan 2020 18:00:49 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3020.oracle.com with ESMTP id 2xj1prkdg6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 15 Jan 2020 18:00:49 +0000 Received: from abhmp0009.oracle.com (abhmp0009.oracle.com [141.146.116.15]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 00FI0cl2026518; Wed, 15 Jan 2020 18:00:39 GMT Received: from kadam (/129.205.23.165) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 15 Jan 2020 10:00:38 -0800 Date: Wed, 15 Jan 2020 21:01:17 +0300 From: Dan Carpenter To: Sean Young Cc: Phong Tran , mchehab@kernel.org, gregkh@linuxfoundation.org, allison@lohutok.net, tglx@linutronix.de, syzbot+6bf9606ee955b646c0e1@syzkaller.appspotmail.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, glider@google.com, syzkaller-bugs@googlegroups.com Subject: Re: [PATCH] media: dvb: check return value digitv_ctrl_msg Message-ID: <20200115180116.GA21151@kadam> References: <0000000000004f3d820596d8c51c@google.com> <20191203004138.21223-1-tranmanphong@gmail.com> <20200115173226.GA24471@gofer.mess.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200115173226.GA24471@gofer.mess.org> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9501 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001150138 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9501 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001150138 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 15, 2020 at 05:32:26PM +0000, Sean Young wrote: > Hello, > > On Tue, Dec 03, 2019 at 07:41:38AM +0700, Phong Tran wrote: > > For fixing syzbot "KMSAN: uninit-value in digitv_rc_query" > > > > In scenario testing for syzbot, failure reading from > > digitv_ctrl_msg() [1]. > > > > Eg: > > [ 91.846657][ T3844] dvb-usb: bulk message failed: -22 (7/0) > > > > digitv_rc_query() always return 0. But in this case a wrong thing happens. > > > > Reported-by: syzbot+6bf9606ee955b646c0e1@syzkaller.appspotmail.com > > Tested-by: syzbot+6bf9606ee955b646c0e1@syzkaller.appspotmail.com > > A fix for this was already merged I'm afraid, see commit eecc70d22ae5 > ("media: digitv: don't continue if remote control state can't be read"). > > > [1]: https://syzkaller.appspot.com/text?tag=CrashLog&x=16860a63600000 > > [2]: https://groups.google.com/d/msg/syzkaller-bugs/-TXIJAZ0J9Q/T4PEUQoeAQAJ > > > > Signed-off-by: Phong Tran > > --- > > drivers/media/usb/dvb-usb/digitv.c | 12 ++++++++---- > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/media/usb/dvb-usb/digitv.c b/drivers/media/usb/dvb-usb/digitv.c > > index dd5bb230cec1..61bc8945e6b9 100644 > > --- a/drivers/media/usb/dvb-usb/digitv.c > > +++ b/drivers/media/usb/dvb-usb/digitv.c > > @@ -231,17 +231,21 @@ static struct rc_map_table rc_map_digitv_table[] = { > > static int digitv_rc_query(struct dvb_usb_device *d, u32 *event, int *state) > > { > > int i; > > - u8 key[5]; > > + u8 key[5] = { 0 }; > > The merged commit does not change this line. Why was this changed? > It would fix the problem that key[0] is never initialized... But the correct fix is to make key 4 elements long and delete key[0]. regards, dan carpenter