linux-kernel - [PATCH 4.16 074/196] ASoC: topology: Fix kcontrol name string handling

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Date:   Sun, 22 Apr 2018 15:51:34 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Liam Girdwood <liam.r.girdwood@...ux.intel.com>,
        Mark Brown <broonie@...nel.org>
Subject: [PATCH 4.16 074/196] ASoC: topology: Fix kcontrol name string handling

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

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

From: Liam Girdwood <liam.r.girdwood@...ux.intel.com>

commit 267e2c6fd7ca3d4076d20f9d52d49dc91addfe9d upstream.

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@...ux.intel.com>
Signed-off-by: Mark Brown <broonie@...nel.org>
Cc: stable@...r.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 sound/soc/soc-topology.c |   23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

--- a/sound/soc/soc-topology.c
+++ b/sound/soc/soc-topology.c
@@ -523,6 +523,7 @@ static void remove_widget(struct snd_soc
 				kfree(se->dobj.control.dtexts[j]);
 
 			kfree(se);
+			kfree(w->kcontrol_news[i].name);
 		}
 		kfree(w->kcontrol_news);
 	} else {
@@ -540,6 +541,7 @@ static void remove_widget(struct snd_soc
 			 */
 			kfree((void *)kcontrol->private_value);
 			snd_ctl_remove(card, kcontrol);
+			kfree(w->kcontrol_news[i].name);
 		}
 		kfree(w->kcontrol_news);
 	}
@@ -1233,7 +1235,9 @@ static struct snd_kcontrol_new *soc_tplg
 		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;
@@ -1278,8 +1282,10 @@ static struct snd_kcontrol_new *soc_tplg
 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;
 }
@@ -1310,7 +1316,9 @@ static struct snd_kcontrol_new *soc_tplg
 		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;
@@ -1386,6 +1394,7 @@ err_se:
 			kfree(se->dobj.control.dtexts[j]);
 
 		kfree(se);
+		kfree(kc[i].name);
 	}
 err:
 	kfree(kc);
@@ -1424,7 +1433,9 @@ static struct snd_kcontrol_new *soc_tplg
 			"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;
@@ -1454,8 +1465,10 @@ static struct snd_kcontrol_new *soc_tplg
 	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;