[PATCH 4.8 051/138] USB: serial: fix potential NULL-dereference at probe

[Greg Kroah-Hartman]

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@xxxxxxxxxx>

commit 126d26f66d9890a69158812a6caa248c05359daa upstream.

Make sure we have at least one port before attempting to register a
console.

Currently, at least one driver binds to a "dummy" interface and requests
zero ports for it. Should such an interface also lack endpoints, we get
a NULL-deref during probe.

Fixes: e5b1e2062e05 ("USB: serial: make minor allocation dynamic")
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/serial/usb-serial.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -1078,7 +1078,8 @@ static int usb_serial_probe(struct usb_i
 
 	serial->disconnected = 0;
 
-	usb_serial_console_init(serial->port[0]->minor);
+	if (num_ports > 0)
+		usb_serial_console_init(serial->port[0]->minor);
 exit:
 	module_put(type->driver.owner);
 	return 0;