if_join_all_router (int sock, struct interface *ifp)
{
  int ret;

  struct ipv6_mreq mreq;

  memset (&mreq, 0, sizeof (struct ipv6_mreq));
  inet_pton (AF_INET6, ALLROUTER, &mreq.ipv6mr_multiaddr);
  mreq.ipv6mr_interface = ifp->ifindex;

  ret = setsockopt (sock, IPPROTO_IPV6, IPV6_JOIN_GROUP, 
		    (char *) &mreq, sizeof mreq);
  if (ret < 0)
    zlog_warn ("can't setsockopt IPV6_JOIN_GROUP: %s", safe_strerror (errno));

  zlog_info ("rtadv: %s join to all-routers multicast group", ifp->name);

  return 0;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.