[PATCH 3.16 229/366] USB: serial: ch341: fix type promotion bug in ch341_control_in()

Ben Hutchings
2018-11-11T20:07:09Z

From: Dan Carpenter <dan.carpenter@oracle.com>

commit e33eab9ded328ccc14308afa51b5be7cbe78d30b upstream.

The "r" variable is an int and "bufsize" is an unsigned int so the
comparison is type promoted to unsigned. If usb_control_msg() returns a
negative that is treated as a high positive value and the error handling
doesn't work.

Fixes: 2d5a9c72d0c4 ("USB: serial: ch341: fix control-message error handling")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/usb/serial/ch341.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -131,7 +131,7 @@ static int ch341_control_in(struct usb_d
r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
value, index, buf, bufsize, DEFAULT_TIMEOUT);
- if (r < bufsize) {
+ if (r < (int)bufsize) {
if (r >= 0) {
dev_err(&dev->dev,
"short control message received (%d < %u)\n",