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netfilter: nf_tables: netlink notifier might race to release objects

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[ Upstream commit d4bc8271db21ea9f1c86a1ca4d64999f184d4aae ]

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: 6001a930ce ("netfilter: nftables: introduce table ownership")
Reported-by: syzbot+8f747f62763bc6c32916@syzkaller.appspotmail.com
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Pablo Neira Ayuso
2022-10-26 09:52:36 +02:00
committed by Greg Kroah-Hartman
parent dcc79cf735
commit 1ffe710041
1 changed files with 2 additions and 0 deletions
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2
net/netfilter/nf_tables_api.c
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@@ -9824,6 +9824,8 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event,
nft_net = nft_pernet(net); nft_net = nft_pernet(net);
deleted = 0; deleted = 0;
mutex_lock(&nft_net->commit_mutex); mutex_lock(&nft_net->commit_mutex);
if (!list_empty(&nf_tables_destroy_list))
rcu_barrier();
again: again:
list_for_each_entry(table, &nft_net->tables, list) { list_for_each_entry(table, &nft_net->tables, list) {
if (nft_table_has_owner(table) && if (nft_table_has_owner(table) &&