[PATCH 4.4 035/101] USB: serial: iuu_phoenix: fix NULL-deref at open

[Greg Kroah-Hartman]

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

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

From: Johan Hovold <johan@xxxxxxxxxx>

commit 90507d54f712d81b74815ef3a4bbb555cd9fab2f upstream.

Fix NULL-pointer dereference at open should the device lack a bulk-in or
bulk-out endpoint:

Unable to handle kernel NULL pointer dereference at virtual address 00000030
...
PC is at iuu_open+0x78/0x59c [iuu_phoenix]

Fixes: 07c3b1a10016 ("USB: remove broken usb-serial num_endpoints
check")
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/serial/iuu_phoenix.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/drivers/usb/serial/iuu_phoenix.c
+++ b/drivers/usb/serial/iuu_phoenix.c
@@ -68,6 +68,16 @@ struct iuu_private {
 	u32 clk;
 };
 
+static int iuu_attach(struct usb_serial *serial)
+{
+	unsigned char num_ports = serial->num_ports;
+
+	if (serial->num_bulk_in < num_ports || serial->num_bulk_out < num_ports)
+		return -ENODEV;
+
+	return 0;
+}
+
 static int iuu_port_probe(struct usb_serial_port *port)
 {
 	struct iuu_private *priv;
@@ -1196,6 +1206,7 @@ static struct usb_serial_driver iuu_devi
 	.tiocmset = iuu_tiocmset,
 	.set_termios = iuu_set_termios,
 	.init_termios = iuu_init_termios,
+	.attach = iuu_attach,
 	.port_probe = iuu_port_probe,
 	.port_remove = iuu_port_remove,
 };