USB: serial: cyberjack: fix NULL-deref at open

commit 3dca0111 upstream.

Fix NULL-pointer dereference when clearing halt at open should the device
lack a bulk-out endpoint.

Unable to handle kernel NULL pointer dereference at virtual address 00000030
...
PC is at cyberjack_open+0x40/0x9c [cyberjack]

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

drivers/usb/serial/cyberjack.c

@@ -51,6 +51,7 @@
 #define CYBERJACK_PRODUCT_ID	0x0100
 
 /* Function prototypes */
+static int cyberjack_attach(struct usb_serial *serial);
 static int cyberjack_port_probe(struct usb_serial_port *port);
 static int cyberjack_port_remove(struct usb_serial_port *port);
 static int  cyberjack_open(struct tty_struct *tty,
@@ -78,6 +79,7 @@ static struct usb_serial_driver cyberjack_device = {
 	.description =		"Reiner SCT Cyberjack USB card reader",
 	.id_table =		id_table,
 	.num_ports =		1,
+	.attach =		cyberjack_attach,
 	.port_probe =		cyberjack_port_probe,
 	.port_remove =		cyberjack_port_remove,
 	.open =			cyberjack_open,
@@ -101,6 +103,14 @@ struct cyberjack_private {
 	short		wrsent;		/* Data already sent */
 };
 
+static int cyberjack_attach(struct usb_serial *serial)
+{
+	if (serial->num_bulk_out < serial->num_ports)
+		return -ENODEV;
+
+	return 0;
+}
+
 static int cyberjack_port_probe(struct usb_serial_port *port)
 {
 	struct cyberjack_private *priv;