From 76f22c93b209c811bd489950f17f8839adb31901 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 23 Jun 2021 10:45:21 +0200 Subject: media: rtl28xxu: fix zero-length control request The direction of the pipe argument must match the request-type direction bit or control requests may fail depending on the host-controller-driver implementation. Control transfers without a data stage are treated as OUT requests by the USB stack and should be using usb_sndctrlpipe(). Failing to do so will now trigger a warning. The driver uses a zero-length i2c-read request for type detection so update the control-request code to use usb_sndctrlpipe() in this case. Note that actually trying to read the i2c register in question does not work as the register might not exist (e.g. depending on the demodulator) as reported by Eero Lehtinen . Reported-by: syzbot+faf11bbadc5a372564da@syzkaller.appspotmail.com Reported-by: Eero Lehtinen Tested-by: Eero Lehtinen Fixes: d0f232e823af ("[media] rtl28xxu: add heuristic to detect chip type") Cc: stable@vger.kernel.org # 4.0 Cc: Antti Palosaari Signed-off-by: Johan Hovold Signed-off-by: Sean Young Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/dvb-usb-v2/rtl28xxu.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'drivers') diff --git a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c index 0cbdb95f8d35..795a012d4020 100644 --- a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c +++ b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c @@ -37,7 +37,16 @@ static int rtl28xxu_ctrl_msg(struct dvb_usb_device *d, struct rtl28xxu_req *req) } else { /* read */ requesttype = (USB_TYPE_VENDOR | USB_DIR_IN); - pipe = usb_rcvctrlpipe(d->udev, 0); + + /* + * Zero-length transfers must use usb_sndctrlpipe() and + * rtl28xxu_identify_state() uses a zero-length i2c read + * command to determine the chip type. + */ + if (req->size) + pipe = usb_rcvctrlpipe(d->udev, 0); + else + pipe = usb_sndctrlpipe(d->udev, 0); } ret = usb_control_msg(d->udev, pipe, 0, requesttype, req->value, -- cgit v1.2.3