[PATCH 3.19.y-ckt 121/146] net/ipv6/udp: Fix ipv6 multicast socket filter regression

[Kamal Mostafa]

3.19.8-ckt2 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Henning Rogge <hrogge at gmail.com>

commit 33b4b015e1a1ca7a8fdce40af5e71642a8ea355c upstream.

Commit <5cf3d46192fc> ("udp: Simplify__udp*_lib_mcast_deliver")
simplified the filter for incoming IPv6 multicast but removed
the check of the local socket address and the UDP destination
address.

This patch restores the filter to prevent sockets bound to a IPv6
multicast IP to receive other UDP traffic link unicast.

Signed-off-by: Henning Rogge <hrogge at gmail.com>
Fixes: 5cf3d46192fc ("udp: Simplify__udp*_lib_mcast_deliver")
Cc: "David S. Miller" <davem at davemloft.net>
Acked-by: Eric Dumazet <edumazet at google.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/ipv6/udp.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 189dc4a..d953a31 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -734,7 +734,9 @@ static bool __udp_v6_is_mcast_sock(struct net *net, struct sock *sk,
 	    (inet->inet_dport && inet->inet_dport != rmt_port) ||
 	    (!ipv6_addr_any(&sk->sk_v6_daddr) &&
 		    !ipv6_addr_equal(&sk->sk_v6_daddr, rmt_addr)) ||
-	    (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
+	    (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif) ||
+	    (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
+		    !ipv6_addr_equal(&sk->sk_v6_rcv_saddr, loc_addr)))
 		return false;
 	if (!inet6_mc_check(sk, loc_addr, rmt_addr))
 		return false;
-- 
1.9.1