[alsa-devel] [PATCH] ASoC: audio-graph-card: fix use-after-free in graph_for_each_link

[Wen Yang]

After calling of_node_put() on the codec_ep and codec_port variables,
they are still being used, which may result in use-after-free.
We fix this issue by calling of_node_put() after the last usage.

Fixes: fce9b90c1ab7 ("ASoC: audio-graph-card: cleanup DAI link loop method - step2")
Signed-off-by: Wen Yang <wen.yang99 at zte.com.cn>
Cc: Liam Girdwood <lgirdwood at gmail.com>
Cc: Mark Brown <broonie at kernel.org>
Cc: Jaroslav Kysela <perex at perex.cz>
Cc: Takashi Iwai <tiwai at suse.com>
Cc: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
Cc: alsa-devel at alsa-project.org
Cc: linux-kernel at vger.kernel.org
---
 sound/soc/generic/audio-graph-card.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sound/soc/generic/audio-graph-card.c b/sound/soc/generic/audio-graph-card.c
index e438011..30a4e83 100644
--- a/sound/soc/generic/audio-graph-card.c
+++ b/sound/soc/generic/audio-graph-card.c
@@ -421,9 +421,6 @@ static int graph_for_each_link(struct asoc_simple_priv *priv,
 			codec_ep = of_graph_get_remote_endpoint(cpu_ep);
 			codec_port = of_get_parent(codec_ep);
 
-			of_node_put(codec_ep);
-			of_node_put(codec_port);
-
 			/* get convert-xxx property */
 			memset(&adata, 0, sizeof(adata));
 			graph_parse_convert(dev, codec_ep, &adata);
@@ -443,6 +440,9 @@ static int graph_for_each_link(struct asoc_simple_priv *priv,
 			else
 				ret = func_noml(priv, cpu_ep, codec_ep, li);
 
+			of_node_put(codec_ep);
+			of_node_put(codec_port);
+
 			if (ret < 0)
 				return ret;
 
-- 
2.9.5