ASoC: topology: Fix route memory corruption

It was reported that recent fix for memory corruption during topology
load, causes corruption in other cases. Instead of being overeager with
checking topology, assume that it is properly formatted and just
duplicate strings.

Reported-by: Pierre-Louis Bossart <[email protected]>
Closes: https://lore.kernel.org/linux-sound/[email protected]/T/#m8c4bd5abf453960fde6f826c4b7f84881da63e9d
Suggested-by: Péter Ujfalusi <[email protected]>
Signed-off-by: Amadeusz Sławiński <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

Author: Amadeusz Sławiński

sound/soc/soc-topology.c

@@ -1052,21 +1052,15 @@ static int soc_tplg_dapm_graph_elems_load(struct soc_tplg *tplg,
 			break;
 		}
 
-		route->source = devm_kmemdup(tplg->dev, elem->source,
-					     min(strlen(elem->source), maxlen),
-					     GFP_KERNEL);
-		route->sink = devm_kmemdup(tplg->dev, elem->sink,
-					   min(strlen(elem->sink), maxlen),
-					   GFP_KERNEL);
+		route->source = devm_kstrdup(tplg->dev, elem->source, GFP_KERNEL);
+		route->sink = devm_kstrdup(tplg->dev, elem->sink, GFP_KERNEL);
 		if (!route->source || !route->sink) {
 			ret = -ENOMEM;
 			break;
 		}
 
 		if (strnlen(elem->control, maxlen) != 0) {
-			route->control = devm_kmemdup(tplg->dev, elem->control,
-						      min(strlen(elem->control), maxlen),
-						      GFP_KERNEL);
+			route->control = devm_kstrdup(tplg->dev, elem->control, GFP_KERNEL);
 			if (!route->control) {
 				ret = -ENOMEM;
 				break;