linux-kernel - [PATCH 4.9 33/39] netfilter: nat: avoid use of nf_conn

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Date:   Thu, 16 Nov 2017 18:42:52 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Florian Westphal <fw@...len.de>,
        Pablo Neira Ayuso <pablo@...filter.org>
Subject: [PATCH 4.9 33/39] netfilter: nat: avoid use of nf_conn_nat extension

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

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

From: Florian Westphal <fw@...len.de>

commit 6e699867f84c0f358fed233fe6162173aca28e04 upstream.

successful insert into the bysource hash sets IPS_SRC_NAT_DONE status bit
so we can check that instead of presence of nat extension which requires
extra deref.

Signed-off-by: Florian Westphal <fw@...len.de>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 net/netfilter/nf_conntrack_core.c |    2 +-
 net/netfilter/nf_nat_core.c       |   18 ++++--------------
 2 files changed, 5 insertions(+), 15 deletions(-)

--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -689,7 +689,7 @@ static int nf_ct_resolve_clash(struct ne
 
 	l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
 	if (l4proto->allow_clash &&
-	    !nfct_nat(ct) &&
+	    ((ct->status & IPS_NAT_DONE_MASK) == 0) &&
 	    !nf_ct_is_dying(ct) &&
 	    atomic_inc_not_zero(&ct->ct_general.use)) {
 		nf_ct_acct_merge(ct, ctinfo, (struct nf_conn *)skb->nfct);
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -550,10 +550,6 @@ struct nf_nat_proto_clean {
 static int nf_nat_proto_remove(struct nf_conn *i, void *data)
 {
 	const struct nf_nat_proto_clean *clean = data;
-	struct nf_conn_nat *nat = nfct_nat(i);
-
-	if (!nat)
-		return 0;
 
 	if ((clean->l3proto && nf_ct_l3num(i) != clean->l3proto) ||
 	    (clean->l4proto && nf_ct_protonum(i) != clean->l4proto))
@@ -564,12 +560,10 @@ static int nf_nat_proto_remove(struct nf
 
 static int nf_nat_proto_clean(struct nf_conn *ct, void *data)
 {
-	struct nf_conn_nat *nat = nfct_nat(ct);
-
 	if (nf_nat_proto_remove(ct, data))
 		return 1;
 
-	if (!nat)
+	if ((ct->status & IPS_SRC_NAT_DONE) == 0)
 		return 0;
 
 	/* This netns is being destroyed, and conntrack has nat null binding.
@@ -705,13 +699,9 @@ EXPORT_SYMBOL_GPL(nf_nat_l3proto_unregis
 /* No one using conntrack by the time this called. */
 static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
 {
-	struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT);
-
-	if (!nat)
-		return;
-
-	rhltable_remove(&nf_nat_bysource_table, &ct->nat_bysource,
-			nf_nat_bysource_params);
+	if (ct->status & IPS_SRC_NAT_DONE)
+		rhltable_remove(&nf_nat_bysource_table, &ct->nat_bysource,
+				nf_nat_bysource_params);
 }
 
 static struct nf_ct_ext_type nat_extend __read_mostly = {