netfilter: nf_conntrack_expect: skip expectations in other netns via proc

Skip expectations that do not reside in this netns.

Similar to e77e6ff502ea ("netfilter: conntrack: do not dump other netns's
conntrack entries via proc").

Fixes: 9b03f38d0487 ("netfilter: netns nf_conntrack: per-netns expectations")
Signed-off-by: Florian Westphal <[e-mail]>
Signed-off-by: Pablo Neira Ayuso <[e-mail]>

net/netfilter/nf_conntrack_expect.c

···
 {
 	struct nf_conntrack_expect *expect;
 	struct nf_conntrack_helper *helper;
+	struct net *net = seq_file_net(s);
 	struct hlist_node *n = v;
 	char *delim = "";
 
 	expect = hlist_entry(n, struct nf_conntrack_expect, hnode);
+
+	if (!net_eq(nf_ct_exp_net(expect), net))
+		return 0;
 
 	if (expect->timeout.function)
 		seq_printf(s, "%ld ", timer_pending(&expect->timeout)