netfilter: pptp: attach nat extension when needed

make sure nat extension gets added if the master conntrack is subject to
NAT.  This will be required once the nat core stops adding it by default.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 21 insertions, 4 deletions

diff --git a/net/ipv4/netfilter/nf_nat_pptp.c b/net/ipv4/netfilter/nf_nat_pptp.c
index 211fee5fe59d..8a69363b4884 100644
--- a/net/ipv4/netfilter/nf_nat_pptp.c
+++ b/net/ipv4/netfilter/nf_nat_pptp.c
@@ -49,9 +49,14 @@ static void pptp_nat_expected(struct nf_conn *ct,
 	const struct nf_ct_pptp_master *ct_pptp_info;
 	const struct nf_nat_pptp *nat_pptp_info;
 	struct nf_nat_range range;
+	struct nf_conn_nat *nat;
 
+	nat = nf_ct_nat_ext_add(ct);
+	if (WARN_ON_ONCE(!nat))
+		return;
+
+	nat_pptp_info = &nat->help.nat_pptp_info;
 	ct_pptp_info = nfct_help_data(master);
-	nat_pptp_info = &nfct_nat(master)->help.nat_pptp_info;
 
 	/* And here goes the grand finale of corrosion... */
 	if (exp->dir == IP_CT_DIR_ORIGINAL) {
@@ -120,13 +125,17 @@ pptp_outbound_pkt(struct sk_buff *skb,
 
 {
 	struct nf_ct_pptp_master *ct_pptp_info;
+	struct nf_conn_nat *nat = nfct_nat(ct);
 	struct nf_nat_pptp *nat_pptp_info;
 	u_int16_t msg;
 	__be16 new_callid;
 	unsigned int cid_off;
 
+	if (WARN_ON_ONCE(!nat))
+		return NF_DROP;
+
+	nat_pptp_info = &nat->help.nat_pptp_info;
 	ct_pptp_info = nfct_help_data(ct);
-	nat_pptp_info = &nfct_nat(ct)->help.nat_pptp_info;
 
 	new_callid = ct_pptp_info->pns_call_id;
 
@@ -191,11 +200,15 @@ pptp_exp_gre(struct nf_conntrack_expect *expect_orig,
 	     struct nf_conntrack_expect *expect_reply)
 {
 	const struct nf_conn *ct = expect_orig->master;
+	struct nf_conn_nat *nat = nfct_nat(ct);
 	struct nf_ct_pptp_master *ct_pptp_info;
 	struct nf_nat_pptp *nat_pptp_info;
 
+	if (WARN_ON_ONCE(!nat))
+		return;
+
+	nat_pptp_info = &nat->help.nat_pptp_info;
 	ct_pptp_info = nfct_help_data(ct);
-	nat_pptp_info = &nfct_nat(ct)->help.nat_pptp_info;
 
 	/* save original PAC call ID in nat_info */
 	nat_pptp_info->pac_call_id = ct_pptp_info->pac_call_id;
@@ -223,11 +236,15 @@ pptp_inbound_pkt(struct sk_buff *skb,
 		 union pptp_ctrl_union *pptpReq)
 {
 	const struct nf_nat_pptp *nat_pptp_info;
+	struct nf_conn_nat *nat = nfct_nat(ct);
 	u_int16_t msg;
 	__be16 new_pcid;
 	unsigned int pcid_off;
 
-	nat_pptp_info = &nfct_nat(ct)->help.nat_pptp_info;
+	if (WARN_ON_ONCE(!nat))
+		return NF_DROP;
+
+	nat_pptp_info = &nat->help.nat_pptp_info;
 	new_pcid = nat_pptp_info->pns_call_id;
 
 	switch (msg = ntohs(ctlh->messageType)) {