From 5dd57e77eff4ba3e85b3df126a55417c88245708 Mon Sep 17 00:00:00 2001 From: Cen Zhang Date: Tue, 20 Oct 2026 21:12:50 +0800 Subject: [PATCH] ocfs2/cluster: remove zero-address nodes from IP tree on teardown o2nm_node_ipv4_address_store() accepts 0.0.0.0. It sets O2NM_NODE_ATTR_ADDRESS and links nd_ip_node into cl_node_ip_tree under cl_nodes_lock, but o2nm_node_group_drop_item() uses nd_ipv4_address as a membership test. A zero address therefore leaves the rbtree node linked when config_item_put() releases and frees struct o2nm_node. A later address store or IP lookup can then walk the stale node and dereference freed memory. During teardown, drop_item takes cl_nodes_lock, skips rb_erase() for the zero key, and then calls config_item_put(). A later o2nm_node_ipv4_address_store() duplicate check or o2nm_get_node_by_ip() lookup takes the same lock and walks the stale cl_node_ip_tree entry. Use O2NM_NODE_ATTR_ADDRESS for teardown so every published nd_ip_node is erased before configfs can release the node, without rejecting 0.0.0.0 or changing lookup semantics. Link: https://lore.kernel.org/pm-ocfs2-node-ip-rbtree-zero-address-uaf-v5-e7f64be16b7c3b0988d1@gmail.com Fixes: 0c83ed8eeb28 ("[PATCH] OCFS2: The Second Oracle Cluster Filesystem") Signed-off-by: Cen Zhang Signed-off-by: Andrew Morton Reviewed-by: Joseph Qi Assisted-by: LLM Cc: Mark Fasheh Cc: Joel Becker Cc: Heming Zhao Cc: Jia-Ju Bai Cc: Cc: --- fs/ocfs2/cluster/nodemanager.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/ocfs2/cluster/nodemanager.c b/fs/ocfs2/cluster/nodemanager.c index ced4fe6d3b59..91f8fcc6193f 100644 --- a/fs/ocfs2/cluster/nodemanager.c +++ b/fs/ocfs2/cluster/nodemanager.c @@ -627,8 +627,11 @@ static void o2nm_node_group_drop_item(struct config_group *group, write_lock(&cluster->cl_nodes_lock); - /* XXX sloppy */ - if (node->nd_ipv4_address) + /* + * 0.0.0.0 is a valid configured address, so nd_ipv4_address does + * not tell us whether nd_ip_node was published in the IP tree. + */ + if (test_bit(O2NM_NODE_ATTR_ADDRESS, &node->nd_set_attributes)) rb_erase(&node->nd_ip_node, &cluster->cl_node_ip_tree); /* nd_num might be 0 if the node number hasn't been set.. */