[alsa-devel] [PATCH] ASoC: topology: Fix kcontrol name string handling.

[Liam Girdwood]

Fix the topology kcontrol string handling so that string pointer
references are strdup()ed instead of being copied. This fixes issues
with kcontrol templates on the stack or ones that are freed. Remember
and free the strings too when topology is unloaded.

Signed-off-by: Liam Girdwood <liam.r.girdwood at linux.intel.com>
---
 sound/soc/soc-topology.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/sound/soc/soc-topology.c b/sound/soc/soc-topology.c
index 78197e82fc4f..dd2b118a35b3 100644
--- a/sound/soc/soc-topology.c
+++ b/sound/soc/soc-topology.c
@@ -530,6 +530,7 @@ static void remove_widget(struct snd_soc_component *comp,
 				kfree(se->dobj.control.dtexts[j]);
 
 			kfree(se);
+			kfree(w->kcontrol_news[i].name);
 		}
 	} else {
 		/* volume mixer or bytes controls */
@@ -546,6 +547,7 @@ static void remove_widget(struct snd_soc_component *comp,
 			 */
 			kfree((void *)kcontrol->private_value);
 			snd_ctl_remove(card, kcontrol);
+			kfree(w->kcontrol_news[i].name);
 		}
 	}
 
@@ -1256,7 +1258,9 @@ static struct snd_kcontrol_new *soc_tplg_dapm_widget_dmixer_create(
 		dev_dbg(tplg->dev, " adding DAPM widget mixer control %s at %d\n",
 			mc->hdr.name, i);
 
-		kc[i].name = mc->hdr.name;
+		kc[i].name = kstrdup(mc->hdr.name, GFP_KERNEL);
+		if (kc[i].name == NULL)
+			goto err_str;
 		kc[i].private_value = (long)sm;
 		kc[i].iface = SNDRV_CTL_ELEM_IFACE_MIXER;
 		kc[i].access = mc->hdr.access;
@@ -1304,8 +1308,10 @@ static struct snd_kcontrol_new *soc_tplg_dapm_widget_dmixer_create(
 err_str:
 	kfree(sm);
 err:
-	for (--i; i >= 0; i--)
+	for (--i; i >= 0; i--) {
 		kfree((void *)kc[i].private_value);
+		kfree(kc[i].name);
+	}
 	kfree(kc);
 	return NULL;
 }
@@ -1336,7 +1342,9 @@ static struct snd_kcontrol_new *soc_tplg_dapm_widget_denum_create(
 		dev_dbg(tplg->dev, " adding DAPM widget enum control %s\n",
 			ec->hdr.name);
 
-		kc[i].name = ec->hdr.name;
+		kc[i].name = kstrdup(ec->hdr.name, GFP_KERNEL);
+		if (kc[i].name == NULL)
+			goto err_se;
 		kc[i].private_value = (long)se;
 		kc[i].iface = SNDRV_CTL_ELEM_IFACE_MIXER;
 		kc[i].access = ec->hdr.access;
@@ -1412,6 +1420,7 @@ static struct snd_kcontrol_new *soc_tplg_dapm_widget_denum_create(
 			kfree(se->dobj.control.dtexts[j]);
 
 		kfree(se);
+		kfree(kc[i].name);
 	}
 err:
 	kfree(kc);
@@ -1450,7 +1459,9 @@ static struct snd_kcontrol_new *soc_tplg_dapm_widget_dbytes_create(
 			"ASoC: adding bytes kcontrol %s with access 0x%x\n",
 			be->hdr.name, be->hdr.access);
 
-		kc[i].name = be->hdr.name;
+		kc[i].name = kstrdup(be->hdr.name, GFP_KERNEL);
+		if (kc[i].name == NULL)
+			goto err;
 		kc[i].private_value = (long)sbe;
 		kc[i].iface = SNDRV_CTL_ELEM_IFACE_MIXER;
 		kc[i].access = be->hdr.access;
@@ -1480,8 +1491,10 @@ static struct snd_kcontrol_new *soc_tplg_dapm_widget_dbytes_create(
 	return kc;
 
 err:
-	for (--i; i >= 0; i--)
+	for (--i; i >= 0; i--) {
 		kfree((void *)kc[i].private_value);
+		kfree(kc[i].name);
+	}
 
 	kfree(kc);
 	return NULL;
-- 
2.14.1