[PATCH 1/2] soc: qcom: smsm: Fix refcount leak bugs in qcom_smsm_probe()

[PATCH 1/2] soc: qcom: smsm: Fix refcount leak bugs in qcom_smsm_probe()

[Liang He]

There are two refcount leak bugs in qcom_smsm_probe():

(1) The 'local_node' is escaped out from for_each_child_of_node() as
the break of iteration, we should call of_node_put() for it in error
path or when it is not used anymore.
(2) The 'node' is escaped out from for_each_available_child_of_node()
as the 'goto', we should call of_node_put() for it in goto target.

Fixes: c97c4090ff72 ("soc: qcom: smsm: Add driver for Qualcomm SMSM")
Signed-off-by: Liang He <windhl@126.com>
---
 drivers/soc/qcom/smsm.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/soc/qcom/smsm.c b/drivers/soc/qcom/smsm.c
index 9df9bba242f3..3e8994d6110e 100644
--- a/drivers/soc/qcom/smsm.c
+++ b/drivers/soc/qcom/smsm.c
@@ -526,7 +526,7 @@ static int qcom_smsm_probe(struct platform_device *pdev)
 	for (id = 0; id < smsm->num_hosts; id++) {
 		ret = smsm_parse_ipc(smsm, id);
 		if (ret < 0)
-			return ret;
+			goto out_put;
 	}
 
 	/* Acquire the main SMSM state vector */
@@ -534,13 +534,14 @@ static int qcom_smsm_probe(struct platform_device *pdev)
 			      smsm->num_entries * sizeof(u32));
 	if (ret < 0 && ret != -EEXIST) {
 		dev_err(&pdev->dev, "unable to allocate shared state entry\n");
-		return ret;
+		goto out_put;
 	}
 
 	states = qcom_smem_get(QCOM_SMEM_HOST_ANY, SMEM_SMSM_SHARED_STATE, NULL);
 	if (IS_ERR(states)) {
 		dev_err(&pdev->dev, "Unable to acquire shared state entry\n");
-		return PTR_ERR(states);
+		ret = PTR_ERR(states);
+		goto out_put;
 	}
 
 	/* Acquire the list of interrupt mask vectors */
@@ -548,13 +549,14 @@ static int qcom_smsm_probe(struct platform_device *pdev)
 	ret = qcom_smem_alloc(QCOM_SMEM_HOST_ANY, SMEM_SMSM_CPU_INTR_MASK, size);
 	if (ret < 0 && ret != -EEXIST) {
 		dev_err(&pdev->dev, "unable to allocate smsm interrupt mask\n");
-		return ret;
+		goto out_put;
 	}
 
 	intr_mask = qcom_smem_get(QCOM_SMEM_HOST_ANY, SMEM_SMSM_CPU_INTR_MASK, NULL);
 	if (IS_ERR(intr_mask)) {
 		dev_err(&pdev->dev, "unable to acquire shared memory interrupt mask\n");
-		return PTR_ERR(intr_mask);
+		ret = PTR_ERR(intr_mask);
+		goto out_put;
 	}
 
 	/* Setup the reference to the local state bits */
@@ -565,7 +567,8 @@ static int qcom_smsm_probe(struct platform_device *pdev)
 	smsm->state = qcom_smem_state_register(local_node, &smsm_state_ops, smsm);
 	if (IS_ERR(smsm->state)) {
 		dev_err(smsm->dev, "failed to register qcom_smem_state\n");
-		return PTR_ERR(smsm->state);
+		ret = PTR_ERR(smsm->state);
+		goto out_put;
 	}
 
 	/* Register handlers for remote processor entries of interest. */
@@ -595,16 +598,19 @@ static int qcom_smsm_probe(struct platform_device *pdev)
 	}
 
 	platform_set_drvdata(pdev, smsm);
+	of_node_put(local_node);
 
 	return 0;
 
 unwind_interfaces:
+	of_node_put(node);
 	for (id = 0; id < smsm->num_entries; id++)
 		if (smsm->entries[id].domain)
 			irq_domain_remove(smsm->entries[id].domain);
 
 	qcom_smem_state_unregister(smsm->state);
-
+out_put:
+	of_node_put(local_node);
 	return ret;
 }
 
-- 
2.25.1

[PATCH 2/2] soc: qcom: smem_state: Add refcounting for the 'state->of_node'

[Liang He]

In qcom_smem_state_register() and qcom_smem_state_release(), we
should better use of_node_get() and of_node_put() for the reference
creation and destruction of 'device_node'.

Fixes: 9460ae2ff308 ("soc: qcom: Introduce common SMEM state machine code")
Signed-off-by: Liang He <windhl@126.com>
---
I have learned that the 'state->of_node' is used to match client
lookups. But I do not know if there will be a premature free or UAF
if we do not refcount this new reference created in to 'state->of_node'.
Please check it carefully.


 drivers/soc/qcom/smem_state.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/qcom/smem_state.c b/drivers/soc/qcom/smem_state.c
index 31faf4aa868e..e848cc9a3cf8 100644
--- a/drivers/soc/qcom/smem_state.c
+++ b/drivers/soc/qcom/smem_state.c
@@ -136,6 +136,7 @@ static void qcom_smem_state_release(struct kref *ref)
 	struct qcom_smem_state *state = container_of(ref, struct qcom_smem_state, refcount);
 
 	list_del(&state->list);
+	of_node_put(state->of_node);
 	kfree(state);
 }
 
@@ -205,7 +206,7 @@ struct qcom_smem_state *qcom_smem_state_register(struct device_node *of_node,
 
 	kref_init(&state->refcount);
 
-	state->of_node = of_node;
+	state->of_node = of_node_get(of_node);
 	state->ops = *ops;
 	state->priv = priv;
 
-- 
2.25.1