tree 006a1c215f05b6cb728dc5f57afab2f8c4eed55e
parent 470bbb9cbd8fe115d844222317666f672d32c1fc
author Takashi Iwai <tiwai@suse.de> 1643208611 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1644341434 +0100

ALSA: hda: Fix UAF of leds class devs at unbinding

commit 549f8ffc7b2f7561bea7f90930b6c5104318e87b upstream.

The LED class devices that are created by HD-audio codec drivers are
registered via devm_led_classdev_register() and associated with the
HD-audio codec device.  Unfortunately, it turned out that the devres
release doesn't work for this case; namely, since the codec resource
release happens before the devm call chain, it triggers a NULL
dereference or a UAF for a stale set_brightness_delay callback.

For fixing the bug, this patch changes the LED class device register
and unregister in a manual manner without devres, keeping the
instances in hda_gen_spec.

Reported-by: Alexander Sergeyev <sergeev917@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220111195229.a77wrpjclqwrx4bx@localhost.localdomain
Link: https://lore.kernel.org/r/20220126145011.16728-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>