From 05bdcf12905533b8628627b6634608cd3b57c607 Mon Sep 17 00:00:00 2001
From: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Date: Wed, 14 Mar 2018 20:42:40 +0000
Subject: [PATCH] ASoC: topology: Check widget kcontrols before deref.
Git-commit: 05bdcf12905533b8628627b6634608cd3b57c607
Patch-mainline: v4.17-rc1
References: bsc#1051510

Validate the topology input before we dereference the pointer.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 sound/soc/soc-topology.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/sound/soc/soc-topology.c
+++ b/sound/soc/soc-topology.c
@@ -485,6 +485,9 @@ static void remove_widget(struct snd_soc
 	if (dobj->ops && dobj->ops->widget_unload)
 		dobj->ops->widget_unload(comp, dobj);
 
+	if (!w->kcontrols)
+		goto free_news;
+
 	/*
 	 * Dynamic Widgets either have 1..N enum kcontrols or mixers.
 	 * The enum may either have an array of values or strings.
@@ -506,7 +509,6 @@ static void remove_widget(struct snd_soc
 			kfree(se);
 			kfree(w->kcontrol_news[i].name);
 		}
-		kfree(w->kcontrol_news);
 	} else {
 		/* volume mixer or bytes controls */
 		for (i = 0; i < w->num_kcontrols; i++) {
@@ -524,8 +526,11 @@ static void remove_widget(struct snd_soc
 			snd_ctl_remove(card, kcontrol);
 			kfree(w->kcontrol_news[i].name);
 		}
-		kfree(w->kcontrol_news);
 	}
+
+free_news:
+	kfree(w->kcontrol_news);
+
 	/* widget w is freed by soc-dapm.c */
 }