release/5.2.38/ASoC-topology-Prevent-use-after-free-in-snd_soc_get_.patch

From dc0cc79bf57377a0622b82a6e3b9624d65dea9c1 Mon Sep 17 00:00:00 2001
From: Dragos Tarcatu <dragos_tarcatu@mentor.com>
Date: Wed, 4 Dec 2019 15:04:47 -0600
Subject: [PATCH] ASoC: topology: Prevent use-after-free in
 snd_soc_get_pcm_runtime()

commit dd836ddf4e4e1c7f1eb2ae44783ccd70872ef24e upstream.

remove_link() is currently calling snd_soc_remove_dai_link() after
it has already freed the memory for the link name. But this is later
read from snd_soc_get_pcm_runtime() causing a KASAN use-after-free
warning. Reorder the cleanups to fix this issue.

Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Dragos Tarcatu <dragos_tarcatu@mentor.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/20191204210447.11701-4-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/sound/soc/soc-topology.c b/sound/soc/soc-topology.c
index 85a23b0f99bb..e24a11010fe5 100644
--- a/sound/soc/soc-topology.c
+++ b/sound/soc/soc-topology.c
@@ -558,12 +558,12 @@ static void remove_link(struct snd_soc_component *comp,
 	if (dobj->ops && dobj->ops->link_unload)
 		dobj->ops->link_unload(comp, dobj);
 
+	list_del(&dobj->list);
+	snd_soc_remove_dai_link(comp->card, link);
+
 	kfree(link->name);
 	kfree(link->stream_name);
 	kfree(link->cpu_dai_name);
-
-	list_del(&dobj->list);
-	snd_soc_remove_dai_link(comp->card, link);
 	kfree(link);
 }
 
-- 
2.7.4