[PATCH net-next] tipc: fix null deref crash in compat config path

msg.dst_sk needs to be set up with a valid socket because some callbacks
later derive the netns from it.

Fixes: 263ea09084d172d ("Revert "genl: Add genlmsg_new_unicast() for unicast message allocation")
Reported-by: Jon Maloy <redacted>
Bisected-by: Jon Maloy [off-list ref]
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by Jon Maloy [off-list ref]
---
 net/tipc/netlink_compat.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/tipc/netlink_compat.c b/net/tipc/netlink_compat.c
index de66d8f..d7d050f 100644
--- a/net/tipc/netlink_compat.c
+++ b/net/tipc/netlink_compat.c

@@ -1105,6 +1105,7 @@ static int tipc_nl_compat_recv(struct sk_buff *skb, struct genl_info *info)
 	msg.req = nlmsg_data(req_nlh) + GENL_HDRLEN + TIPC_GENL_HDRLEN;
 	msg.cmd = req_userhdr->cmd;
 	msg.net = genl_info_net(info);
+	msg.dst_sk = skb->sk;
 
 	if ((msg.cmd & 0xC000) && (!netlink_net_capable(skb, CAP_NET_ADMIN))) {
 		msg.rep = tipc_get_err_tlv(TIPC_CFG_NOT_NET_ADMIN);

-- 
2.4.10

From: Florian Westphal <fw@strlen.de>
Date: Wed, 24 Feb 2016 17:20:17 +0100

msg.dst_sk needs to be set up with a valid socket because some callbacks
later derive the netns from it.

Fixes: 263ea09084d172d ("Revert "genl: Add genlmsg_new_unicast() for unicast message allocation")
Reported-by: Jon Maloy <redacted>
Bisected-by: Jon Maloy [off-list ref]
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by Jon Maloy [off-list ref]

Applied.