netfilter: Pass socket pointer down through okfn().

On the output paths in particular, we have to sometimes deal with two
socket contexts.  First, and usually skb->sk, is the local socket that
generated the frame.

And second, is potentially the socket used to control a tunneling
socket, such as one the encapsulates using UDP.

We do not want to disassociate skb->sk when encapsulating in order
to fix this, because that would break socket memory accounting.

The most extreme case where this can cause huge problems is an
AF_PACKET socket transmitting over a vxlan device.  We hit code
paths doing checks that assume they are dealing with an ipv4
socket, but are actually operating upon the AF_PACKET one.

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 37 insertions, 29 deletions

diff --git a/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c
index be1f08c..4507b18 100644
--- a/net/decnet/dn_neigh.c
+++ b/net/decnet/dn_neigh.c
@@ -194,7 +194,7 @@ static int dn_neigh_output(struct neighbour *neigh, struct sk_buff *skb)
 	return err;
 }
 
-static int dn_neigh_output_packet(struct sk_buff *skb)
+static int dn_neigh_output_packet(struct sock *sk, struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
 	struct dn_route *rt = (struct dn_route *)dst;
@@ -206,7 +206,8 @@ static int dn_neigh_output_packet(struct sk_buff *skb)
 /*
  * For talking to broadcast devices: Ethernet & PPP
  */
-static int dn_long_output(struct neighbour *neigh, struct sk_buff *skb)
+static int dn_long_output(struct neighbour *neigh, struct sock *sk,
+			  struct sk_buff *skb)
 {
 	struct net_device *dev = neigh->dev;
 	int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
@@ -245,14 +246,15 @@ static int dn_long_output(struct neighbour *neigh, struct sk_buff *skb)
 
 	skb_reset_network_header(skb);
 
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
-		       neigh->dev, dn_neigh_output_packet);
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, sk, skb,
+		       NULL, neigh->dev, dn_neigh_output_packet);
 }
 
 /*
  * For talking to pointopoint and multidrop devices: DDCMP and X.25
  */
-static int dn_short_output(struct neighbour *neigh, struct sk_buff *skb)
+static int dn_short_output(struct neighbour *neigh, struct sock *sk,
+			   struct sk_buff *skb)
 {
 	struct net_device *dev = neigh->dev;
 	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
@@ -284,8 +286,8 @@ static int dn_short_output(struct neighbour *neigh, struct sk_buff *skb)
 
 	skb_reset_network_header(skb);
 
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
-		       neigh->dev, dn_neigh_output_packet);
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, sk, skb,
+		       NULL, neigh->dev, dn_neigh_output_packet);
 }
 
 /*
@@ -293,7 +295,8 @@ static int dn_short_output(struct neighbour *neigh, struct sk_buff *skb)
  * Phase 3 output is the same as short output, execpt that
  * it clears the area bits before transmission.
  */
-static int dn_phase3_output(struct neighbour *neigh, struct sk_buff *skb)
+static int dn_phase3_output(struct neighbour *neigh, struct sock *sk,
+			    struct sk_buff *skb)
 {
 	struct net_device *dev = neigh->dev;
 	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
@@ -324,11 +327,11 @@ static int dn_phase3_output(struct neighbour *neigh, struct sk_buff *skb)
 
 	skb_reset_network_header(skb);
 
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, skb, NULL,
-		       neigh->dev, dn_neigh_output_packet);
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_POST_ROUTING, sk, skb,
+		       NULL, neigh->dev, dn_neigh_output_packet);
 }
 
-int dn_to_neigh_output(struct sk_buff *skb)
+int dn_to_neigh_output(struct sock *sk, struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
 	struct dn_route *rt = (struct dn_route *) dst;
@@ -347,11 +350,11 @@ int dn_to_neigh_output(struct sk_buff *skb)
 	rcu_read_unlock();
 
 	if (dn->flags & DN_NDFLAG_P3)
-		return dn_phase3_output(neigh, skb);
+		return dn_phase3_output(neigh, sk, skb);
 	if (use_long)
-		return dn_long_output(neigh, skb);
+		return dn_long_output(neigh, sk, skb);
 	else
-		return dn_short_output(neigh, skb);
+		return dn_short_output(neigh, sk, skb);
 }
 
 /*
@@ -372,7 +375,7 @@ void dn_neigh_pointopoint_hello(struct sk_buff *skb)
 /*
  * Ethernet router hello message received
  */
-int dn_neigh_router_hello(struct sk_buff *skb)
+int dn_neigh_router_hello(struct sock *sk, struct sk_buff *skb)
 {
 	struct rtnode_hello_message *msg = (struct rtnode_hello_message *)skb->data;
 
@@ -434,7 +437,7 @@ int dn_neigh_router_hello(struct sk_buff *skb)
 /*
  * Endnode hello message received
  */
-int dn_neigh_endnode_hello(struct sk_buff *skb)
+int dn_neigh_endnode_hello(struct sock *sk, struct sk_buff *skb)
 {
 	struct endnode_hello_message *msg = (struct endnode_hello_message *)skb->data;
 	struct neighbour *neigh;
diff --git a/net/decnet/dn_nsp_in.c b/net/decnet/dn_nsp_in.c
index fe5f014..a321eac 100644
--- a/net/decnet/dn_nsp_in.c
+++ b/net/decnet/dn_nsp_in.c
@@ -714,7 +714,7 @@ out:
 	return ret;
 }
 
-static int dn_nsp_rx_packet(struct sk_buff *skb)
+static int dn_nsp_rx_packet(struct sock *sk2, struct sk_buff *skb)
 {
 	struct dn_skb_cb *cb = DN_SKB_CB(skb);
 	struct sock *sk = NULL;
@@ -814,7 +814,8 @@ free_out:
 
 int dn_nsp_rx(struct sk_buff *skb)
 {
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_IN, skb, skb->dev, NULL,
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_IN, NULL, skb,
+		       skb->dev, NULL,
 		       dn_nsp_rx_packet);
 }
 
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 9ab0c4b..03227ff 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -512,7 +512,7 @@ static int dn_return_long(struct sk_buff *skb)
  *
  * Returns: result of input function if route is found, error code otherwise
  */
-static int dn_route_rx_packet(struct sk_buff *skb)
+static int dn_route_rx_packet(struct sock *sk, struct sk_buff *skb)
 {
 	struct dn_skb_cb *cb;
 	int err;
@@ -573,7 +573,8 @@ static int dn_route_rx_long(struct sk_buff *skb)
 	ptr++;
 	cb->hops = *ptr++; /* Visit Count */
 
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, NULL, skb,
+		       skb->dev, NULL,
 		       dn_route_rx_packet);
 
 drop_it:
@@ -600,7 +601,8 @@ static int dn_route_rx_short(struct sk_buff *skb)
 	ptr += 2;
 	cb->hops = *ptr & 0x3f;
 
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, skb, skb->dev, NULL,
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_PRE_ROUTING, NULL, skb,
+		       skb->dev, NULL,
 		       dn_route_rx_packet);
 
 drop_it:
@@ -608,7 +610,7 @@ drop_it:
 	return NET_RX_DROP;
 }
 
-static int dn_route_discard(struct sk_buff *skb)
+static int dn_route_discard(struct sock *sk, struct sk_buff *skb)
 {
 	/*
 	 * I know we drop the packet here, but thats considered success in
@@ -618,7 +620,7 @@ static int dn_route_discard(struct sk_buff *skb)
 	return NET_RX_SUCCESS;
 }
 
-static int dn_route_ptp_hello(struct sk_buff *skb)
+static int dn_route_ptp_hello(struct sock *sk, struct sk_buff *skb)
 {
 	dn_dev_hello(skb);
 	dn_neigh_pointopoint_hello(skb);
@@ -704,22 +706,22 @@ int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type
 		switch (flags & DN_RT_CNTL_MSK) {
 		case DN_RT_PKT_HELO:
 			return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
-				       skb, skb->dev, NULL,
+				       NULL, skb, skb->dev, NULL,
 				       dn_route_ptp_hello);
 
 		case DN_RT_PKT_L1RT:
 		case DN_RT_PKT_L2RT:
 			return NF_HOOK(NFPROTO_DECNET, NF_DN_ROUTE,
-				       skb, skb->dev, NULL,
+				       NULL, skb, skb->dev, NULL,
 				       dn_route_discard);
 		case DN_RT_PKT_ERTH:
 			return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
-				       skb, skb->dev, NULL,
+				       NULL, skb, skb->dev, NULL,
 				       dn_neigh_router_hello);
 
 		case DN_RT_PKT_EEDH:
 			return NF_HOOK(NFPROTO_DECNET, NF_DN_HELLO,
-				       skb, skb->dev, NULL,
+				       NULL, skb, skb->dev, NULL,
 				       dn_neigh_endnode_hello);
 		}
 	} else {
@@ -768,7 +770,8 @@ static int dn_output(struct sock *sk, struct sk_buff *skb)
 	cb->rt_flags |= DN_RT_F_IE;
 	cb->hops = 0;
 
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT, skb, NULL, dev,
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_LOCAL_OUT, sk, skb,
+		       NULL, dev,
 		       dn_to_neigh_output);
 
 error:
@@ -816,7 +819,8 @@ static int dn_forward(struct sk_buff *skb)
 	if (rt->rt_flags & RTCF_DOREDIRECT)
 		cb->rt_flags |= DN_RT_F_IE;
 
-	return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD, skb, dev, skb->dev,
+	return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD, NULL, skb,
+		       dev, skb->dev,
 		       dn_to_neigh_output);
 
 drop: