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/unix/af_unix.c b/net/unix/af_unix.c
index 178d3af..7553ea6 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1259,7 +1259,7 @@
 {
 	struct sock *sk = sock->sk;
 	struct unix_sock *u;
-	struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
+	DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
 	int err = 0;
 
 	if (peer) {