[alsa-devel] [PATCH v2 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_pcm_runtime() 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 | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sound/soc/soc-topology.c b/sound/soc/soc-topology.c
index f8bd406c6198..2b3c74a0b126 100644
--- a/sound/soc/soc-topology.c
+++ b/sound/soc/soc-topology.c
@@ -548,14 +548,14 @@ static void remove_link(struct snd_soc_component *comp,
 	if (dobj->ops && dobj->ops->link_unload)
 		dobj->ops->link_unload(comp, dobj);
 
-	kfree(link->name);
-	kfree(link->stream_name);
-	kfree(link->cpus->dai_name);
-
 	list_del(&dobj->list);
 
 	snd_soc_remove_pcm_runtime(comp->card,
 			snd_soc_get_pcm_runtime(comp->card, link));
+
+	kfree(link->name);
+	kfree(link->stream_name);
+	kfree(link->cpus->dai_name);
 	kfree(link);
 }
 
-- 
2.20.1