isisd: check vertex type before checking its data

vertex->N is an union whose "id" and "ip" fields are only valid
depending on the vertex type (IS adjacency or IP reachability
information). As such, add a vertex type check before consulting
vertex->N.id in order to prevent unexpected behavior from happening.

Signed-off-by: Renato Westphal <[email protected]>

Author: rwestphal

isisd/isis_spf.c

@@ -1521,7 +1521,8 @@ static void isis_print_paths(struct vty *vty, struct isis_vertex_queue *queue,
 		"Vertex               Type         Metric Next-Hop             Interface Parent\n");
 
 	for (ALL_QUEUE_ELEMENTS_RO(queue, node, vertex)) {
-		if (memcmp(vertex->N.id, root_sysid, ISIS_SYS_ID_LEN) == 0) {
+		if (VTYPE_IS(vertex->type)
+		    && memcmp(vertex->N.id, root_sysid, ISIS_SYS_ID_LEN) == 0) {
 			vty_out(vty, "%-20s %-12s %-6s",
 				print_sys_hostname(root_sysid), "", "");
 			vty_out(vty, "%-30s\n", "");