batadv_neigh_node_create() is used to create a neigh node object, whose fields will be initialized with the specific object. When a new reference of the specific object is created during the initialization, its refcount should be increased.

However, when "neigh_node" object initializes its orig_node field with the "orig_node" object, the function forgets to hold the refcount of the "orig_node", causing a potential refcount leak and use-after-free issue for the reason that the object can be freed in other places.

Fix this issue by increasing the refcount of orig_node object during the initialization and adding corresponding batadv_orig_node_put() in batadv_neigh_node_release().

Signed-off-by: Xiyu Yang xiyuyang19@fudan.edu.cn Signed-off-by: Xin Tan tanxin.ctf@gmail.com --- net/batman-adv/originator.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c index 805d8969bdfb..d6c2296f8e35 100644 --- a/net/batman-adv/originator.c +++ b/net/batman-adv/originator.c @@ -306,6 +306,8 @@ static void batadv_neigh_node_release(struct kref *ref)

batadv_hardif_put(neigh_node->if_incoming);

+ batadv_orig_node_put(neigh_node->orig_node); + kfree_rcu(neigh_node, rcu); }

@@ -685,6 +687,7 @@ batadv_neigh_node_create(struct batadv_orig_node *orig_node, kref_get(&hard_iface->refcount); ether_addr_copy(neigh_node->addr, neigh_addr); neigh_node->if_incoming = hard_iface; + kref_get(&orig_node->refcount); neigh_node->orig_node = orig_node; neigh_node->last_seen = jiffies;