[IPV4/6]: Netfilter IPsec input hooks

When the innermost transform uses transport mode the decapsulated packet
is not visible to netfilter. Pass the packet through the PRE_ROUTING and
LOCAL_IN hooks again before handing it to upper layer protocols to make
netfilter-visibility symetrical to the output path.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 31 insertions, 0 deletions

diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index 2d3849c38a0f..850d919591d1 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -11,6 +11,8 @@
 
 #include <linux/module.h>
 #include <linux/string.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.h>
 #include <net/inet_ecn.h>
 #include <net/ip.h>
 #include <net/xfrm.h>
@@ -45,6 +47,23 @@ static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, u32 *spi, u32 *seq)
         return xfrm_parse_spi(skb, nexthdr, spi, seq);
 }
 
+#ifdef CONFIG_NETFILTER
+static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
+{
+        struct iphdr *iph = skb->nh.iph;
+
+        if (skb->dst == NULL) {
+                if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
+                                   skb->dev))
+                        goto drop;
+        }
+        return dst_input(skb);
+drop:
+        kfree_skb(skb);
+        return NET_RX_DROP;
+}
+#endif
+
 int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
 {
         int err;
@@ -137,6 +156,8 @@ int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
         memcpy(skb->sp->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
         skb->sp->len += xfrm_nr;
 
+        nf_reset(skb);
+
         if (decaps) {
                 if (!(skb->dev->flags&IFF_LOOPBACK)) {
                         dst_release(skb->dst);
@@ -145,7 +166,17 @@ int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
                 netif_rx(skb);
                 return 0;
         } else {
+#ifdef CONFIG_NETFILTER
+                __skb_push(skb, skb->data - skb->nh.raw);
+                skb->nh.iph->tot_len = htons(skb->len);
+                ip_send_check(skb->nh.iph);
+
+                NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
+                        xfrm4_rcv_encap_finish);
+                return 0;
+#else
                 return -skb->nh.iph->protocol;
+#endif
         }
 
 drop_unlock: