media: rc: do not access device via sysfs after rc_unregister_device()

Device drivers do not expect to have change_protocol or wakeup
re-programming to be accesed after rc_unregister_device(). This can
cause the device driver to access deallocated resources.

Cc: <stable@vger.kernel.org> # 4.16+
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c
index e1cda80..dee8a9f 100644 (file)
--- a/drivers/media/rc/rc-main.c
+++ b/drivers/media/rc/rc-main.c
@@ -1292,6 +1292,10 @@ static ssize_t store_protocols(struct device *device,
        }
 
        mutex_lock(&dev->lock);
+       if (!dev->registered) {
+               mutex_unlock(&dev->lock);
+               return -ENODEV;
+       }
 
        old_protocols = *current_protocols;
        new_protocols = old_protocols;
@@ -1430,6 +1434,10 @@ static ssize_t store_filter(struct device *device,
                return -EINVAL;
 
        mutex_lock(&dev->lock);
+       if (!dev->registered) {
+               mutex_unlock(&dev->lock);
+               return -ENODEV;
+       }
 
        new_filter = *filter;
        if (fattr->mask)
@@ -1544,6 +1552,10 @@ static ssize_t store_wakeup_protocols(struct device *device,
        int i;
 
        mutex_lock(&dev->lock);
+       if (!dev->registered) {
+               mutex_unlock(&dev->lock);
+               return -ENODEV;
+       }
 
        allowed = dev->allowed_wakeup_protocols;