netfilter: nf_nat: Also handle non-ESTABLISHED routing changes in MASQUERADE

Since (a0ecb85 netfilter: nf_nat: Handle routing changes in MASQUERADE
target), the MASQUERADE target handles routing changes which affect
the output interface of a connection, but only for ESTABLISHED
connections.  It is also possible for NEW connections which
already have a conntrack entry to be affected by routing changes.

This adds a check to drop entries in the NEW+conntrack state
when the oif has changed.

Signed-off-by: Andrew Collins <bsderandrew@gmail.com>
Acked-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 10 insertions, 5 deletions

diff --git a/net/ipv4/netfilter/iptable_nat.c b/net/ipv4/netfilter/iptable_nat.c
index da2c8a368f68..eeaff7e4acb5 100644
--- a/net/ipv4/netfilter/iptable_nat.c
+++ b/net/ipv4/netfilter/iptable_nat.c
@@ -124,23 +124,28 @@ nf_nat_ipv4_fn(unsigned int hooknum,
                         ret = nf_nat_rule_find(skb, hooknum, in, out, ct);
                         if (ret != NF_ACCEPT)
                                 return ret;
-                } else
+                } else {
                         pr_debug("Already setup manip %s for ct %p\n",
                                  maniptype == NF_NAT_MANIP_SRC ? "SRC" : "DST",
                                  ct);
+                        if (nf_nat_oif_changed(hooknum, ctinfo, nat, out))
+                                goto oif_changed;
+                }
                 break;
 
         default:
                 /* ESTABLISHED */
                 NF_CT_ASSERT(ctinfo == IP_CT_ESTABLISHED ||
                              ctinfo == IP_CT_ESTABLISHED_REPLY);
-                if (nf_nat_oif_changed(hooknum, ctinfo, nat, out)) {
-                        nf_ct_kill_acct(ct, ctinfo, skb);
-                        return NF_DROP;
-                }
+                if (nf_nat_oif_changed(hooknum, ctinfo, nat, out))
+                        goto oif_changed;
         }
 
         return nf_nat_packet(ct, ctinfo, hooknum, skb);
+
+oif_changed:
+        nf_ct_kill_acct(ct, ctinfo, skb);
+        return NF_DROP;
 }
 
 static unsigned int