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[3.19.y-ckt,150/170] ipv4: fix broadcast packets reception

Message ID 1459558456-24452-151-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa April 2, 2016, 12:53 a.m. UTC 
3.19.8-ckt18 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Paolo Abeni <pabeni@redhat.com>

commit ad0ea1989cc4d5905941d0a9e62c63ad6d859cef upstream.

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: Kamal Mostafa <kamal@canonical.com>
---
 net/ipv4/udp.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
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Patch

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index b833848..d569a84 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1985,10 +1985,14 @@  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) {