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

On Thu, Dec 13, 2018 at 7:26 AM Pablo Neira Ayuso [off-list ref] wrote:

On Wed, Dec 05, 2018 at 08:56:29PM +0800, Yafang Shao wrote:

quoted

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 <redacted>
---
 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);

There is another spot missing in this file that is missing the check
for NULL.

We can probably simplify all this is we place the gre conntracker in
the conntrack core, as it's been suggested already. It's the only one
remaining as a module and it now supports for IPv6, so it's probably
better follow that path.

Got it.
Thanks for your explanation.

Thanks
Yafang