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>

1 files changed, 6 insertions, 6 deletions

diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c
index dab73813cb92..2878dbfffeb7 100644
--- a/net/ipv4/xfrm4_output.c
+++ b/net/ipv4/xfrm4_output.c
@@ -69,7 +69,7 @@ int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
 }
 EXPORT_SYMBOL(xfrm4_prepare_output);
 
-int xfrm4_output_finish(struct sk_buff *skb)
+int xfrm4_output_finish(struct sock *sk, struct sk_buff *skb)
 {
 	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 
@@ -77,26 +77,26 @@ int xfrm4_output_finish(struct sk_buff *skb)
 	IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
 #endif
 
-	return xfrm_output(skb);
+	return xfrm_output(sk, skb);
 }
 
-static int __xfrm4_output(struct sk_buff *skb)
+static int __xfrm4_output(struct sock *sk, struct sk_buff *skb)
 {
 	struct xfrm_state *x = skb_dst(skb)->xfrm;
 
 #ifdef CONFIG_NETFILTER
 	if (!x) {
 		IPCB(skb)->flags |= IPSKB_REROUTED;
-		return dst_output(skb);
+		return dst_output_sk(sk, skb);
 	}
 #endif
 
-	return x->outer_mode->afinfo->output_finish(skb);
+	return x->outer_mode->afinfo->output_finish(sk, skb);
 }
 
 int xfrm4_output(struct sock *sk, struct sk_buff *skb)
 {
-	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb,
+	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, sk, skb,
 			    NULL, skb_dst(skb)->dev, __xfrm4_output,
 			    !(IPCB(skb)->flags & IPSKB_REROUTED));
 }