From: Paolo Abeni <pabeni@redhat.com>
Date: Tue, 22 Mar 2016 08:19:38 +0000 (+0100)
Subject: ipv4: fix broadcast packets reception
X-Git-Tag: v4.9.8~2423^2~14
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ad0ea1989cc4d5905941d0a9e62c63ad6d859cef;p=platform%2Fkernel%2Flinux-rpi3.git

ipv4: fix broadcast packets reception

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>
---

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 836abe5..08eed5e 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2070,10 +2070,14 @@ 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) {