ALSA: hda: Skip event processing for unregistered codecs

When codec is unbound but not yet removed, in the eyes of
snd_hdac_bus_process_unsol_events() it is still a valid target to
delegate work to. Such behaviour may lead to use-after-free errors.
Address by verifying if codec is actually registered.
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20220706120230.427296-6-cezary.rojewski@intel.comSigned-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/hda_codec.h

@@ -231,7 +231,6 @@ struct hda_codec {
 	/* misc flags */
 	unsigned int configured:1; /* codec was configured */
 	unsigned int in_freeing:1; /* being released */
-	unsigned int registered:1; /* codec was registered */
 	unsigned int display_power_control:1; /* needs display power */
 	unsigned int spdif_status_reset :1; /* needs to toggle SPDIF for each
 					     * status change

include/sound/hdaudio.h

@@ -93,6 +93,7 @@ struct hdac_device {
 	bool lazy_cache:1;	/* don't wake up for writes */
 	bool caps_overwriting:1; /* caps overwrite being in process */
 	bool cache_coef:1;	/* cache COEF read/write too */
+	unsigned int registered:1; /* codec was registered */
 };
 
 /* device/driver type used for matching */

sound/hda/hdac_bus.c

@@ -183,7 +183,7 @@ static void snd_hdac_bus_process_unsol_events(struct work_struct *work)
 		if (!(caddr & (1 << 4))) /* no unsolicited event? */
 			continue;
 		codec = bus->caddr_tbl[caddr & 0x0f];
-		if (!codec || !codec->dev.driver)
+		if (!codec || !codec->registered)
 			continue;
 		spin_unlock_irq(&bus->reg_lock);
 		drv = drv_to_hdac_driver(codec->dev.driver);

sound/pci/hda/hda_codec.c

@@ -772,11 +772,11 @@ static void codec_release_pcms(struct hda_codec *codec)
  */
 void snd_hda_codec_cleanup_for_unbind(struct hda_codec *codec)
 {
-	if (codec->registered) {
+	if (codec->core.registered) {
 		/* pm_runtime_put() is called in snd_hdac_device_exit() */
 		pm_runtime_get_noresume(hda_codec_dev(codec));
 		pm_runtime_disable(hda_codec_dev(codec));
-		codec->registered = 0;
+		codec->core.registered = 0;
 	}
 
 	snd_hda_codec_disconnect_pcms(codec);
@@ -825,14 +825,14 @@ void snd_hda_codec_display_power(struct hda_codec *codec, bool enable)
  */
 void snd_hda_codec_register(struct hda_codec *codec)
 {
-	if (codec->registered)
+	if (codec->core.registered)
 		return;
 	if (device_is_registered(hda_codec_dev(codec))) {
 		snd_hda_codec_display_power(codec, true);
 		pm_runtime_enable(hda_codec_dev(codec));
 		/* it was powered up in snd_hda_codec_new(), now all done */
 		snd_hda_power_down(codec);
-		codec->registered = 1;
+		codec->core.registered = 1;
 	}
 }
 EXPORT_SYMBOL_GPL(snd_hda_codec_register);
@@ -3047,7 +3047,7 @@ void snd_hda_codec_shutdown(struct hda_codec *codec)
 	struct hda_pcm *cpcm;
 
 	/* Skip the shutdown if codec is not registered */
-	if (!codec->registered)
+	if (!codec->core.registered)
 		return;
 
 	cancel_delayed_work_sync(&codec->jackpoll_work);

sound/soc/codecs/hda.c

@@ -274,7 +274,7 @@ static void hda_codec_remove(struct snd_soc_component *component)
 	struct hdac_device *hdev = &codec->core;
 	struct hdac_bus *bus = hdev->bus;
 	struct hdac_ext_link *hlink;
-	bool was_registered = codec->registered;
+	bool was_registered = codec->core.registered;
 
 	/* Don't allow any more runtime suspends */
 	pm_runtime_forbid(&hdev->dev);
@@ -376,7 +376,7 @@ static int hda_hdev_detach(struct hdac_device *hdev)
 {
 	struct hda_codec *codec = dev_to_hda_codec(&hdev->dev);
 
-	if (codec->registered)
+	if (codec->core.registered)
 		cancel_delayed_work_sync(&codec->jackpoll_work);
 
 	snd_soc_unregister_component(&hdev->dev);