[PATCH 4/5] netfilter: fix missed NULL check in nf_conntrack_proto_pernet_init()

[Yafang Shao]

nf_ct_l4proto_net() may return NULL.
That may happens if some module forget to set both l4proto->get_net_proto
and l4proto->net_id.
We'd check the return value here, in case crash happens.

Signed-off-by: Yafang Shao <laoar.s...@gmail.com>
---
 net/netfilter/nf_conntrack_proto.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/netfilter/nf_conntrack_proto.c 
b/net/netfilter/nf_conntrack_proto.c
index 154e8c0..316fef3 100644
--- a/net/netfilter/nf_conntrack_proto.c
+++ b/net/netfilter/nf_conntrack_proto.c
@@ -946,6 +946,9 @@ int nf_conntrack_proto_pernet_init(struct net *net)
        struct nf_proto_net *pn = nf_ct_l4proto_net(net,
                                        &nf_conntrack_l4proto_generic);
 
+       if (pn == NULL)
+               return -EINVAL;
+
        err = nf_conntrack_l4proto_generic.init_net(net);
        if (err < 0)
                return err;
-- 
1.8.3.1