[PATCH 4.16 039/279] ASoC: topology: Check widget kcontrols before deref.

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

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

From: Liam Girdwood <liam.r.girdwood@xxxxxxxxxxxxxxx>

[ Upstream commit 05bdcf12905533b8628627b6634608cd3b57c607 ]

Validate the topology input before we dereference the pointer.

Signed-off-by: Liam Girdwood <liam.r.girdwood@xxxxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 sound/soc/soc-topology.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/sound/soc/soc-topology.c
+++ b/sound/soc/soc-topology.c
@@ -510,7 +510,7 @@ static void remove_widget(struct snd_soc
 	 */
 	if (dobj->widget.kcontrol_type == SND_SOC_TPLG_TYPE_ENUM) {
 		/* enumerated widget mixer */
-		for (i = 0; i < w->num_kcontrols; i++) {
+		for (i = 0; w->kcontrols != NULL && i < w->num_kcontrols; i++) {
 			struct snd_kcontrol *kcontrol = w->kcontrols[i];
 			struct soc_enum *se =
 				(struct soc_enum *)kcontrol->private_value;
@@ -528,7 +528,7 @@ static void remove_widget(struct snd_soc
 		kfree(w->kcontrol_news);
 	} else {
 		/* volume mixer or bytes controls */
-		for (i = 0; i < w->num_kcontrols; i++) {
+		for (i = 0; w->kcontrols != NULL && i < w->num_kcontrols; i++) {
 			struct snd_kcontrol *kcontrol = w->kcontrols[i];
 
 			if (dobj->widget.kcontrol_type