ASoC: audio-graph-card: fix an use-after-free in graph_get_dai_id()

After calling of_node_put() on the node variable, it is still being
used, which may result in use-after-free.
Fix this issue by calling of_node_put() after the last usage.

Fixes: a0c426fe1433 ("ASoC: simple-card-utils: check "reg" property on asoc_simple_card_get_dai_id()")
Link: https://lore.kernel.org/r/1562743509-30496-5-git-send-email-wen.yang99@zte.com.cn
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/generic/audio-graph-card.c b/sound/soc/generic/audio-graph-card.c
index bddfcfd7bedfaefcea65d3997971139b870373d5..343ede8042c3f5615cf1d6722f2f03d289574b0e 100644 (file)
--- a/sound/soc/generic/audio-graph-card.c
+++ b/sound/soc/generic/audio-graph-card.c
@@ -63,6 +63,7 @@ static int graph_get_dai_id(struct device_node *ep)
        struct device_node *endpoint;
        struct of_endpoint info;
        int i, id;
+       u32 *reg;
        int ret;
 
        /* use driver specified DAI ID if exist */
@@ -83,8 +84,9 @@ static int graph_get_dai_id(struct device_node *ep)
                        return info.id;
 
                node = of_get_parent(ep);
+               reg = of_get_property(node, "reg", NULL);
                of_node_put(node);
-               if (of_get_property(node, "reg", NULL))
+               if (reg)
                        return info.port;
        }
        node = of_graph_get_port_parent(ep);