net: ax25: fix information leak to userland harder

Commit fe10ae53 adds a memset() to clear
the structure being sent back to userspace, but accidentally used the
wrong size.
Reported-by: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Cc: stable@kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ax25/af_ax25.c

@@ -1392,7 +1392,7 @@ static int ax25_getname(struct socket *sock, struct sockaddr *uaddr,
 	ax25_cb *ax25;
 	int err = 0;
 
-	memset(fsa, 0, sizeof(fsa));
+	memset(fsa, 0, sizeof(*fsa));
 	lock_sock(sk);
 	ax25 = ax25_sk(sk);