netfilter: pptp: attach nat extension when needed

[mirror_ubuntu-artful-kernel.git] / net / ipv4 / netfilter / nf_nat_pptp.c

diff --git a/net/ipv4/netfilter/nf_nat_pptp.c b/net/ipv4/netfilter/nf_nat_pptp.c
index 211fee5fe59d7f1379ae7899d94c7a750f05c7dd..8a69363b48846c628994e54c92a354ca46f71ebc 100644 (file)
--- 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)) {