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From: Phong Tran <tranmanphong@gmail.com>
To: mchehab@kernel.org, gregkh@linuxfoundation.org,
	allison@lohutok.net, tglx@linutronix.de,
	syzbot+6bf9606ee955b646c0e1@syzkaller.appspotmail.com
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
	glider@google.com, syzkaller-bugs@googlegroups.com,
	Phong Tran <tranmanphong@gmail.com>
Subject: [PATCH] media: dvb: check return value digitv_ctrl_msg
Date: Tue,  3 Dec 2019 07:41:38 +0700	[thread overview]
Message-ID: <20191203004138.21223-1-tranmanphong@gmail.com> (raw)
In-Reply-To: <0000000000004f3d820596d8c51c@google.com>

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

[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 <tranmanphong@gmail.com>
---
 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 };
 	u8 b[4] = { 0 };
+	int ret;
 
 	*event = 0;
 	*state = REMOTE_NO_KEY_PRESSED;
 
-	digitv_ctrl_msg(d,USB_READ_REMOTE,0,NULL,0,&key[1],4);
-
+	ret = digitv_ctrl_msg(d, USB_READ_REMOTE, 0, NULL, 0, &key[1], 4);
+	if (ret < 0)
+		return ret;
 	/* Tell the device we've read the remote. Not sure how necessary
 	   this is, but the Nebula SDK does it. */
-	digitv_ctrl_msg(d,USB_WRITE_REMOTE,0,b,4,NULL,0);
+	ret = digitv_ctrl_msg(d, USB_WRITE_REMOTE, 0, b, 4, NULL, 0);
+	if (ret < 0)
+		return ret;
 
 	/* if something is inside the buffer, simulate key press */
 	if (key[1] != 0)
-- 
2.20.1


  reply	other threads:[~2019-12-03  0:41 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-08 17:04 KMSAN: uninit-value in digitv_rc_query syzbot
2019-12-03  0:41 ` Phong Tran [this message]
2020-01-15 17:32   ` [PATCH] media: dvb: check return value digitv_ctrl_msg Sean Young
2020-01-15 18:01     ` Dan Carpenter
2020-01-15 18:15       ` Dan Carpenter

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