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, 5 insertions, 4 deletions

diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index fac1f27e428e..083b2927fc67 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1644,8 +1644,9 @@ static void mld_sendpack(struct sk_buff *skb)
 
         payload_len = skb->len;
 
-        err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL, skb->dev,
-                      dst_output);
+        err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
+                      net->ipv6.igmp_sk, skb, NULL, skb->dev,
+                      dst_output_sk);
 out:
         if (!err) {
                 ICMP6MSGOUT_INC_STATS(net, idev, ICMPV6_MLD2_REPORT);
@@ -2007,8 +2008,8 @@ static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
         }
 
         skb_dst_set(skb, dst);
-        err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL, skb->dev,
-                      dst_output);
+        err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, sk, skb,
+                      NULL, skb->dev, dst_output_sk);
 out:
         if (!err) {
                 ICMP6MSGOUT_INC_STATS(net, idev, type);