rfkill: Use mutex_lock() at register and add sanity check

Replace mutex_lock_interruptible() by mutex_lock() in rfkill_register(),
as interruptible doesn't make sense there.

Add a sanity check for rfkill->type, as that's used for an unchecked dereference
in an array and might cause hard to debug crashes if the driver sets this
to an invalid value.
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/rfkill/rfkill.c

@@ -276,21 +276,17 @@ static struct class rfkill_class = {
 
 static int rfkill_add_switch(struct rfkill *rfkill)
 {
-	int retval;
-
-	retval = mutex_lock_interruptible(&rfkill_mutex);
-	if (retval)
-		return retval;
+	int error;
 
-	retval = rfkill_toggle_radio(rfkill, rfkill_states[rfkill->type]);
-	if (retval)
-		goto out;
+	mutex_lock(&rfkill_mutex);
 
+	error = rfkill_toggle_radio(rfkill, rfkill_states[rfkill->type]);
+	if (!error)
 		list_add_tail(&rfkill->node, &rfkill_list);
 
- out:
 	mutex_unlock(&rfkill_mutex);
-	return retval;
+
+	return error;
 }
 
 static void rfkill_remove_switch(struct rfkill *rfkill)
@@ -387,6 +383,8 @@ int rfkill_register(struct rfkill *rfkill)
 
 	if (!rfkill->toggle_radio)
 		return -EINVAL;
+	if (rfkill->type >= RFKILL_TYPE_MAX)
+		return -EINVAL;
 
 	snprintf(dev->bus_id, sizeof(dev->bus_id),
 		 "rfkill%ld", (long)atomic_inc_return(&rfkill_no) - 1);