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

From: Greg Kroah-Hartman
Date: Wed Nov 09 2016 - 06:07:13 EST


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;