ipv4: fix broadcast packets reception

[ Upstream commit ad0ea1989cc4d5905941d0a9e62c63ad6d859cef ]

Currently, ingress ipv4 broadcast datagrams are dropped since,
in udp_v4_early_demux(), ip_check_mc_rcu() is invoked even on
bcast packets.

This patch addresses the issue, invoking ip_check_mc_rcu()
only for mcast packets.

Fixes: 6e5403093261 ("ipv4/udp: Verify multicast group is ours in upd_v4_early_demux()")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index a390174..031752e 100644 (file)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1979,10 +1979,14 @@ void udp_v4_early_demux(struct sk_buff *skb)
                if (!in_dev)
                        return;
 
-               ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr,
-                                      iph->protocol);
-               if (!ours)
-                       return;
+               /* we are supposed to accept bcast packets */
+               if (skb->pkt_type == PACKET_MULTICAST) {
+                       ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr,
+                                              iph->protocol);
+                       if (!ours)
+                               return;
+               }
+
                sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr,
                                                   uh->source, iph->saddr, dif);
        } else if (skb->pkt_type == PACKET_HOST) {