netfilter: nf_tables: flush pending destroy work before netlink notifier

[ Upstream commit 2c9f0293280e258606e54ed2b96fa71498432eae ]

Destroy work waits for the RCU grace period then it releases the objects
with no mutex held. All releases objects follow this path for
transactions, therefore, order is guaranteed and references to top-level
objects in the hierarchy remain valid.

However, netlink notifier might interfer with pending destroy work.
rcu_barrier() is not correct because objects are not release via RCU
callback. Flush destroy work before releasing objects from netlink
notifier path.

Fixes: d4bc8271db21 ("netfilter: nf_tables: netlink notifier might race to release objects")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 4c2df7af73f76f97434e57a548593ed0034de9ba..3c5cac9bd9b70db5c96cc6f9e8f8d20e85f290ef 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -10509,7 +10509,7 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event,
        deleted = 0;
        mutex_lock(&nft_net->commit_mutex);
        if (!list_empty(&nf_tables_destroy_list))
-               rcu_barrier();
+               nf_tables_trans_destroy_flush_work();
 again:
        list_for_each_entry(table, &nft_net->tables, list) {
                if (nft_table_has_owner(table) &&