[PATCH v3] drivers/base/node: fix UAF on device_register() failure

[Linkai Gong]

node_init_node_access() frees the access node with kfree() if
device_register() fails. After device_register() the embedded device is
initialized and must be released with put_device() so that
node_access_release() can free it.

Fixes: 08d9dbe72b1f ("node: Link memory nodes to their compute nodes")
Signed-off-by: Linkai Gong <gonglinkai@xxxxxxxxxx>
---
v3:
- drop both goto labels; the error paths just return (Danilo)

v2:
- rename the free_name error label to put_device (Danilo)

 drivers/base/node.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 3da91929ad4e..dcdc8626627a 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -167,20 +167,19 @@ static struct node_access_nodes *node_init_node_access(struct node *node,
 	dev->parent = &node->dev;
 	dev->release = node_access_release;
 	dev->groups = node_access_node_groups;
-	if (dev_set_name(dev, "access%u", access))
-		goto free;
+	if (dev_set_name(dev, "access%u", access)) {
+		kfree(access_node);
+		return NULL;
+	}
 
-	if (device_register(dev))
-		goto free_name;
+	if (device_register(dev)) {
+		put_device(dev);
+		return NULL;
+	}
 
 	pm_runtime_no_callbacks(dev);
 	list_add_tail(&access_node->list_node, &node->access_list);
 	return access_node;
-free_name:
-	kfree_const(dev->kobj.name);
-free:
-	kfree(access_node);
-	return NULL;
 }
 
 #ifdef CONFIG_HMEM_REPORTING
-- 
2.25.1