From a9f5e78c403d2d62ade4f4c85040efc85f4049b8 Mon Sep 17 00:00:00 2001 From: Li RongQing Date: Tue, 26 Feb 2019 17:13:56 +0800 Subject: netfilter: nf_tables: check the result of dereferencing base_chain->stats Check the result of dereferencing base_chain->stats, instead of result of this_cpu_ptr with NULL. base_chain->stats maybe be changed to NULL when a chain is updated and a new NULL counter can be attached. And we do not need to check returning of this_cpu_ptr since base_chain->stats is from percpu allocator if it is non-NULL, this_cpu_ptr returns a valid value. And fix two sparse error by replacing rcu_access_pointer and rcu_dereference with READ_ONCE under rcu_read_lock. Thanks for Eric's help to finish this patch. Fixes: 009240940e84c1 ("netfilter: nf_tables: don't assume chain stats are set when jumplabel is set") Signed-off-by: Eric Dumazet Signed-off-by: Zhang Yu Signed-off-by: Li RongQing Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_core.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'net/netfilter') diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c index e56a94dff34e..d0f168c2670f 100644 --- a/net/netfilter/nf_tables_core.c +++ b/net/netfilter/nf_tables_core.c @@ -98,21 +98,23 @@ static noinline void nft_update_chain_stats(const struct nft_chain *chain, const struct nft_pktinfo *pkt) { struct nft_base_chain *base_chain; + struct nft_stats __percpu *pstats; struct nft_stats *stats; base_chain = nft_base_chain(chain); - if (!rcu_access_pointer(base_chain->stats)) - return; - local_bh_disable(); - stats = this_cpu_ptr(rcu_dereference(base_chain->stats)); - if (stats) { + rcu_read_lock(); + pstats = READ_ONCE(base_chain->stats); + if (pstats) { + local_bh_disable(); + stats = this_cpu_ptr(pstats); u64_stats_update_begin(&stats->syncp); stats->pkts++; stats->bytes += pkt->skb->len; u64_stats_update_end(&stats->syncp); + local_bh_enable(); } - local_bh_enable(); + rcu_read_unlock(); } struct nft_jumpstack { -- cgit v1.2.3-59-g8ed1b