Commit f4dcf06b authored by Dinghao Liu's avatar Dinghao Liu Committed by Rafael J. Wysocki
Browse files

ACPI: video: Fix NULL pointer dereference in acpi_video_bus_add() 



acpi_video_bus_add_notify_handler() could free video->input and
set it to NULL on failure, but this failure would be missed in its
caller acpi_video_bus_add(). As a result, when an error happens in
acpi_dev_install_notify_handler(), acpi_video_bus_add() would call
acpi_video_bus_remove_notify_handler(), where a potential NULL pointer
video->input is dereferenced in input_unregister_device().

Fix this by adding a return value check and adjusting the following
error handling code.

Fixes: 6f701681 ("ACPI: video: Install Notify() handler directly")
Signed-off-by: default avatarDinghao Liu <dinghao.liu@zju.edu.cn>
[ rjw: Subject and changelog edits ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 6465e260

drivers/acpi/acpi_video.c

+5 −2
Original line number Diff line number Diff line
@@ -2057,7 +2057,9 @@ static int acpi_video_bus_add(struct acpi_device *device) 
	    !auto_detect)

		acpi_video_bus_register_backlight(video);



	acpi_video_bus_add_notify_handler(video);

	error = acpi_video_bus_add_notify_handler(video);

	if (error)

		goto err_del;



	error = acpi_dev_install_notify_handler(device, ACPI_DEVICE_NOTIFY,

						acpi_video_bus_notify);
@@ -2067,10 +2069,11 @@ static int acpi_video_bus_add(struct acpi_device *device) 
	return 0;



err_remove:

	acpi_video_bus_remove_notify_handler(video);

err_del:

	mutex_lock(&video_list_lock);

	list_del(&video->entry);

	mutex_unlock(&video_list_lock);

	acpi_video_bus_remove_notify_handler(video);

	acpi_video_bus_unregister_backlight(video);

err_put_video:

	acpi_video_bus_put_devices(video);