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 5275c4112b57dd934ecafc2823613a1eb2dbf16e..539bc5d5c12fd7ba50000ba5d127ef66c42901b1 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -11084,7 +11084,7 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event,
        gc_seq = nft_gc_seq_begin(nft_net);
 
        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) &&