From d4bc8271db21ea9f1c86a1ca4d64999f184d4aae Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Wed, 26 Oct 2022 09:52:36 +0200 Subject: netfilter: nf_tables: netlink notifier might race to release objects commit release path is invoked via call_rcu and it runs lockless to release the objects after rcu grace period. The netlink notifier handler might win race to remove objects that the transaction context is still referencing from the commit release path. Call rcu_barrier() to ensure pending rcu callbacks run to completion if the list of transactions to be destroyed is not empty. Fixes: 6001a930ce03 ("netfilter: nftables: introduce table ownership") Reported-by: syzbot+8f747f62763bc6c32916@syzkaller.appspotmail.com Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_api.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net') diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 58d9cbc9ccdc..2197118aa7b0 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -10030,6 +10030,8 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event, nft_net = nft_pernet(net); deleted = 0; mutex_lock(&nft_net->commit_mutex); + if (!list_empty(&nf_tables_destroy_list)) + rcu_barrier(); again: list_for_each_entry(table, &nft_net->tables, list) { if (nft_table_has_owner(table) && -- cgit v1.2.3