ASoC: topology: Fix references to freed memory

Most users after parsing a topology file, release memory used by it, so
having pointer references directly into topology file contents is wrong.
Use devm_kmemdup(), to allocate memory as needed.

Reported-by: Jason Montleon <jmontleo@redhat.com>
Link: thesofproject/avs-topology-xml#22 (comment)
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Link: https://lore.kernel.org/r/20240603102818.36165-2-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: Amadeusz Sławiński

sound/soc/soc-topology.c

@@ -1060,15 +1060,32 @@ static int soc_tplg_dapm_graph_elems_load(struct soc_tplg *tplg,
 			break;
 		}
 
-		route->source = elem->source;
-		route->sink = elem->sink;
+		route->source = devm_kmemdup(tplg->dev, elem->source,
+					     min(strlen(elem->source),
+						 SNDRV_CTL_ELEM_ID_NAME_MAXLEN),
+					     GFP_KERNEL);
+		route->sink = devm_kmemdup(tplg->dev, elem->sink,
+					   min(strlen(elem->sink), SNDRV_CTL_ELEM_ID_NAME_MAXLEN),
+					   GFP_KERNEL);
+		if (!route->source || !route->sink) {
+			ret = -ENOMEM;
+			break;
+		}
 
 		/* set to NULL atm for tplg users */
 		route->connected = NULL;
-		if (strnlen(elem->control, SNDRV_CTL_ELEM_ID_NAME_MAXLEN) == 0)
+		if (strnlen(elem->control, SNDRV_CTL_ELEM_ID_NAME_MAXLEN) == 0) {
 			route->control = NULL;
-		else
-			route->control = elem->control;
+		} else {
+			route->control = devm_kmemdup(tplg->dev, elem->control,
+						      min(strlen(elem->control),
+							  SNDRV_CTL_ELEM_ID_NAME_MAXLEN),
+						      GFP_KERNEL);
+			if (!route->control) {
+				ret = -ENOMEM;
+				break;
+			}
+		}
 
 		/* add route dobj to dobj_list */
 		route->dobj.type = SND_SOC_DOBJ_GRAPH;