[alsa-devel] [PATCH 3/3] ASoC: topology: Prevent use-after-free in snd_soc_get_pcm_runtime()

[Pierre-Louis Bossart]

From: Dragos Tarcatu <dragos_tarcatu at mentor.com>

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 at linux.intel.com>
Signed-off-by: Dragos Tarcatu <dragos_tarcatu at mentor.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
---
 sound/soc/soc-topology.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sound/soc/soc-topology.c b/sound/soc/soc-topology.c
index 81d2af000a5c..248530d028a6 100644
--- a/sound/soc/soc-topology.c
+++ b/sound/soc/soc-topology.c
@@ -548,12 +548,12 @@ 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->cpus->dai_name);
-
-	list_del(&dobj->list);
-	snd_soc_remove_dai_link(comp->card, link);
 	kfree(link);
 }
 
-- 
2.20.1