diff --git a/drivers/input/mousedev.c b/drivers/input/mousedev.c
index 30328e57fdda..095c7dd87eae 100644
--- a/drivers/input/mousedev.c
+++ b/drivers/input/mousedev.c
@@ -750,7 +750,7 @@ static ssize_t mousedev_read(struct file *file, char __user *buffer,
 
 	spin_unlock_irq(&client->packet_lock);
 
-	if (copy_to_user(buffer, data, count))
+	if (count > sizeof(data) || copy_to_user(buffer, data, count))
 		return -EFAULT;
 
 	return count;