[PATCH 4.14 26/61] netfilter: nf_tables: dont assume chain stats are set when jumplabel is set

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Florian Westphal <fw@xxxxxxxxx>

commit 009240940e84c1c089af88b454f7e804a4c5bd1b upstream.

nft_chain_stats_replace() and all other spots assume ->stats can be
NULL, but nft_update_chain_stats does not.  It must do this check,
just because the jump label is set doesn't mean all basechains have stats
assigned.

Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 net/netfilter/nf_tables_core.c |   21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

--- a/net/netfilter/nf_tables_core.c
+++ b/net/netfilter/nf_tables_core.c
@@ -119,15 +119,22 @@ DEFINE_STATIC_KEY_FALSE(nft_counters_ena
 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 *stats;
 
-	local_bh_disable();
-	stats = this_cpu_ptr(rcu_dereference(nft_base_chain(chain)->stats));
-	u64_stats_update_begin(&stats->syncp);
-	stats->pkts++;
-	stats->bytes += pkt->skb->len;
-	u64_stats_update_end(&stats->syncp);
-	local_bh_enable();
+	base_chain = nft_base_chain(chain);
+	if (!base_chain->stats)
+		return;
+
+	stats = this_cpu_ptr(rcu_dereference(base_chain->stats));
+	if (stats) {
+		local_bh_disable();
+		u64_stats_update_begin(&stats->syncp);
+		stats->pkts++;
+		stats->bytes += pkt->skb->len;
+		u64_stats_update_end(&stats->syncp);
+		local_bh_enable();
+	}
 }
 
 struct nft_jumpstack {