[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@xxxxxxxxxx>
Cc: Liam Girdwood <lgirdwood@xxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: Jaroslav Kysela <perex@xxxxxxxx>
Cc: Takashi Iwai <tiwai@xxxxxxxx>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
Cc: alsa-devel@xxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/1562229530-8121-1-git-send-email-wen.yang99@xxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
 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 ec7e673ba475..70ed28d97d49 100644
--- a/sound/soc/generic/audio-graph-card.c
+++ b/sound/soc/generic/audio-graph-card.c
@@ -435,9 +435,6 @@ 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);
@@ -457,6 +454,9 @@ 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;
 
-- 
2.20.1