net: fix raw socket lookup device bind matching with VRFs

When there exist a pair of raw sockets one unbound and one bound
to a VRF but equal in all other respects, when a packet is received
in the VRF context, __raw_v4_lookup() matches on both sockets.

This results in the packet being delivered over both sockets,
instead of only the raw socket bound to the VRF. The bound device
checks in __raw_v4_lookup() are replaced with a call to
raw_sk_bound_dev_eq() which correctly handles whether the packet
should be delivered over the unbound socket in such cases.

In __raw_v6_lookup() the match on the device binding of the socket is
similarly updated to use raw_sk_bound_dev_eq() which matches the
handling in __raw_v4_lookup().

Importantly raw_sk_bound_dev_eq() takes the raw_l3mdev_accept sysctl
into account.

Signed-off-by: Duncan Eastoe <deastoe@vyatta.att-mail.com>
Signed-off-by: Mike Manning <mmanning@vyatta.att-mail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/raw.h

@@ -17,7 +17,7 @@
 #ifndef _RAW_H
 #define _RAW_H
 
-
+#include <net/inet_sock.h>
 #include <net/protocol.h>
 #include <linux/icmp.h>
 
@@ -75,4 +75,15 @@ static inline struct raw_sock *raw_sk(const struct sock *sk)
 	return (struct raw_sock *)sk;
 }
 
+static inline bool raw_sk_bound_dev_eq(struct net *net, int bound_dev_if,
+				       int dif, int sdif)
+{
+#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
+	return inet_bound_dev_eq(!!net->ipv4.sysctl_raw_l3mdev_accept,
+				 bound_dev_if, dif, sdif);
+#else
+	return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
+#endif
+}
+
 #endif	/* _RAW_H */