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

stable inclusion
from stable-v5.10.99
commit a7de1002135cf94367748ffc695a29812d7633b5
bugzilla: https://gitee.com/openeuler/kernel/issues/I55O7H

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a7de1002135cf94367748ffc695a29812d7633b5

--------------------------------

commit 549f8ffc 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: NAlexander 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.deSigned-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

sound/pci/hda/hda_generic.c

@@ -91,6 +91,12 @@ static void snd_hda_gen_spec_free(struct hda_gen_spec *spec)
 	free_kctls(spec);
 	snd_array_free(&spec->paths);
 	snd_array_free(&spec->loopback_list);
+#ifdef CONFIG_SND_HDA_GENERIC_LEDS
+	if (spec->led_cdevs[LED_AUDIO_MUTE])
+		led_classdev_unregister(spec->led_cdevs[LED_AUDIO_MUTE]);
+	if (spec->led_cdevs[LED_AUDIO_MICMUTE])
+		led_classdev_unregister(spec->led_cdevs[LED_AUDIO_MICMUTE]);
+#endif
 }
 
 /*
@@ -3911,7 +3917,10 @@ static int create_mute_led_cdev(struct hda_codec *codec,
 						enum led_brightness),
 				bool micmute)
 {
+	struct hda_gen_spec *spec = codec->spec;
 	struct led_classdev *cdev;
+	int idx = micmute ? LED_AUDIO_MICMUTE : LED_AUDIO_MUTE;
+	int err;
 
 	cdev = devm_kzalloc(&codec->core.dev, sizeof(*cdev), GFP_KERNEL);
 	if (!cdev)
@@ -3921,10 +3930,14 @@ static int create_mute_led_cdev(struct hda_codec *codec,
 	cdev->max_brightness = 1;
 	cdev->default_trigger = micmute ? "audio-micmute" : "audio-mute";
 	cdev->brightness_set_blocking = callback;
-	cdev->brightness = ledtrig_audio_get(micmute ? LED_AUDIO_MICMUTE : LED_AUDIO_MUTE);
+	cdev->brightness = ledtrig_audio_get(idx);
 	cdev->flags = LED_CORE_SUSPENDRESUME;
 
-	return devm_led_classdev_register(&codec->core.dev, cdev);
+	err = led_classdev_register(&codec->core.dev, cdev);
+	if (err < 0)
+		return err;
+	spec->led_cdevs[idx] = cdev;
+	return 0;
 }
 
 static void vmaster_update_mute_led(void *private_data, int enabled)

sound/pci/hda/hda_generic.h

@@ -305,6 +305,9 @@ struct hda_gen_spec {
 				   struct hda_jack_callback *cb);
 	void (*mic_autoswitch_hook)(struct hda_codec *codec,
 				    struct hda_jack_callback *cb);
+
+	/* leds */
+	struct led_classdev *led_cdevs[NUM_AUDIO_LEDS];
 };
 
 /* values for add_stereo_mix_input flag */