[PATCH v5 02/20] media: rc: Ensure that rc_unregister_device() does not free input device

[Sean Young <sean@mess.org>]

During or after rc_unregister_device(), IR may still be reported which
results in a input event being reported. This could result in a null
pointer deref in rc_keydown() or a use-after-free of the input device if
the pointer was read before it is set to NULL.

Fixes: dccc0c3ddf8f ("media: rc: fix race between unregister and urb/irq callbacks")
Signed-off-by: Sean Young <sean@mess.org>
Cc: stable@vger.kernel.org
---
 drivers/media/rc/rc-main.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c
index 930d45517229..d4baaae3a834 100644
--- a/drivers/media/rc/rc-main.c
+++ b/drivers/media/rc/rc-main.c
@@ -1753,7 +1753,7 @@ void rc_free_device(struct rc_dev *dev)
 	if (!dev)
 		return;
 
-	input_free_device(dev->input_dev);
+	input_put_device(dev->input_dev);
 
 	put_device(&dev->dev);
 
@@ -1865,6 +1865,8 @@ static int rc_setup_rx_device(struct rc_dev *dev)
 	if (rc)
 		return rc;
 
+	input_get_device(dev->input_dev);
+
 	/*
 	 * Default delay of 250ms is too short for some protocols, especially
 	 * since the timeout is currently set to 250ms. Increase it to 500ms,
@@ -1891,10 +1893,8 @@ static void rc_free_rx_device(struct rc_dev *dev)
 	if (!dev)
 		return;
 
-	if (dev->input_dev) {
+	if (dev->input_dev)
 		input_unregister_device(dev->input_dev);
-		dev->input_dev = NULL;
-	}
 
 	ir_free_table(&dev->rc_map);
 }
-- 
2.55.0