From 76f22c93b209c811bd489950f17f8839adb31901 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Wed, 23 Jun 2021 10:45:21 +0200
Subject: [PATCH] media: rtl28xxu: fix zero-length control request
Git-commit: 76f22c93b209c811bd489950f17f8839adb31901
Patch-mainline: v5.14-rc5
References: git-fixes
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 <debiangamer2@gmail.com>.
Reported-by: syzbot+faf11bbadc5a372564da@syzkaller.appspotmail.com
Reported-by: Eero Lehtinen <debiangamer2@gmail.com>
Tested-by: Eero Lehtinen <debiangamer2@gmail.com>
Fixes: d0f232e823af ("[media] rtl28xxu: add heuristic to detect chip type")
Cc: stable@vger.kernel.org # 4.0
Cc: Antti Palosaari <crope@iki.fi>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/media/usb/dvb-usb-v2/rtl28xxu.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
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,
--
2.26.2