[PATCH 5.4 057/110] ASoC: topology: Prevent use-after-free in snd_soc_get_pcm_runtime()

[Greg Kroah-Hartman]

From: Dragos Tarcatu <dragos_tarcatu@xxxxxxxxxx>

[ Upstream commit dd836ddf4e4e1c7f1eb2ae44783ccd70872ef24e ]

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@xxxxxxxxxxxxxxx>
Signed-off-by: Dragos Tarcatu <dragos_tarcatu@xxxxxxxxxx>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
Reviewed-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20191204210447.11701-4-pierre-louis.bossart@xxxxxxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 fd2d22ddc81b0..7ccbca47240d7 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