telnetd from 0.4c dumps core

[Richard Nyberg <rnyberg@it.su.se>]

We've had problems with telnetd dumping core when we telnet to the machine 
using the -F option to forward tickets. The supplied patch fixes the 
problem.

address_order in addr_families.c didn't check the return value from 
find_atype, though I do not know why telnetd only dumped core when we 
used forwarding.

	-Richard
--- heimdal-0.4c/lib/krb5/addr_families.c	Tue Jul  3 00:26:42 2001
+++ heimdal-0.4c-rnyberg/lib/krb5/addr_families.c	Mon Jul 23 15:36:35 2001
@@ -741,10 +741,10 @@
        should we call? this works for now, though */
     struct addr_operations *a;
     a = find_atype(addr1->addr_type); 
-    if(a->order_addr != NULL) 
+    if(a != NULL && a->order_addr != NULL) 
 	return (*a->order_addr)(context, addr1, addr2); 
     a = find_atype(addr2->addr_type); 
-    if(a->order_addr != NULL) 
+    if(a != NULL && a->order_addr != NULL) 
 	return (*a->order_addr)(context, addr1, addr2);
 
     if(addr1->addr_type != addr2->addr_type)