net: netlink_getname, packet_getname -- use DECLARE_SOCKADDR guard

Use guard DECLARE_SOCKADDR in a few more places which allow
us to catch if the structure copied back is too big.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index aea805c..f30d596 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -708,7 +708,7 @@
 {
 	struct sock *sk = sock->sk;
 	struct netlink_sock *nlk = nlk_sk(sk);
-	struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
+	DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
 
 	nladdr->nl_family = AF_NETLINK;
 	nladdr->nl_pad = 0;