ASoC: qcom: common: Fix refcounting in qcom_snd_parse_of()

[ Upstream commit 4e59dd249cd513a211e2ecce2cb31f4e29a5ce5b ]

There are two issues in this function.

1) We can't drop the refrences on "cpu", "codec" and "platform" before
   we take the reference.  This doesn't cause a problem on the first
   iteration because those pointers start as NULL so the of_node_put()
   is a no-op.  But on the subsequent iterations, it will lead to a use
   after free.

2) If the devm_kzalloc() allocation failed then the code returned
   directly instead of cleaning up.

Fixes: c1e6414cdc37 ("ASoC: qcom: common: Fix refcount imbalance on error")
Fixes: 1e36ea360ab9 ("ASoC: qcom: common: use modern dai_link style")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20201105125154.GA176426@mwanda
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/sound/soc/qcom/common.c b/sound/soc/qcom/common.c
index 54660f1..09af007 100644 (file)
--- a/sound/soc/qcom/common.c
+++ b/sound/soc/qcom/common.c
@@ -58,7 +58,7 @@ int qcom_snd_parse_of(struct snd_soc_card *card)
                dlc = devm_kzalloc(dev, 2 * sizeof(*dlc), GFP_KERNEL);
                if (!dlc) {
                        ret = -ENOMEM;
-                       goto err;
+                       goto err_put_np;
                }
 
                link->cpus      = &dlc[0];
@@ -70,7 +70,7 @@ int qcom_snd_parse_of(struct snd_soc_card *card)
                ret = of_property_read_string(np, "link-name", &link->name);
                if (ret) {
                        dev_err(card->dev, "error getting codec dai_link name\n");
-                       goto err;
+                       goto err_put_np;
                }
 
                cpu = of_get_child_by_name(np, "cpu");
@@ -130,8 +130,10 @@ int qcom_snd_parse_of(struct snd_soc_card *card)
                } else {
                        /* DPCM frontend */
                        dlc = devm_kzalloc(dev, sizeof(*dlc), GFP_KERNEL);
-                       if (!dlc)
-                               return -ENOMEM;
+                       if (!dlc) {
+                               ret = -ENOMEM;
+                               goto err;
+                       }
 
                        link->codecs     = dlc;
                        link->num_codecs = 1;
@@ -158,10 +160,11 @@ int qcom_snd_parse_of(struct snd_soc_card *card)
 
        return 0;
 err:
-       of_node_put(np);
        of_node_put(cpu);
        of_node_put(codec);
        of_node_put(platform);
+err_put_np:
+       of_node_put(np);
        return ret;
 }
 EXPORT_SYMBOL(qcom_snd_parse_of);