configure_env(char **env, const char *prefix, const struct dhcp_message *dhcp,
 const struct if_options *ifo)
{
 unsigned int i;
 const uint8_t *p;
 int pl;
 struct in_addr addr;
 struct in_addr net;
 struct in_addr brd;
 char *val, *v;
 const struct dhcp_opt *opt;
 ssize_t len, e = 0;
 char **ep;
 char cidr[4];
 uint8_t overl = 0;

	get_option_uint8(&overl, dhcp, DHO_OPTIONSOVERLOADED);

 if (!env) {
 for (opt = dhcp_opts; opt->option; opt++) {
 if (!opt->var)
 continue;
 if (has_option_mask(ifo->nomask, opt->option))
 continue;
 if (get_option_raw(dhcp, opt->option))
				e++;
 }
 if (dhcp->yiaddr || dhcp->ciaddr)
			e += 5;
 if (*dhcp->bootfile && !(overl & 1))
			e++;
 if (*dhcp->servername && !(overl & 2))
			e++;
 return e;
 }

	ep = env;
 if (dhcp->yiaddr || dhcp->ciaddr) {
 /* Set some useful variables that we derive from the DHCP
		 * message but are not necessarily in the options */
		addr.s_addr = dhcp->yiaddr ? dhcp->yiaddr : dhcp->ciaddr;
		setvar(&ep, prefix, "ip_address", inet_ntoa(addr));
 if (get_option_addr(&net, dhcp, DHO_SUBNETMASK) == -1) {
			net.s_addr = get_netmask(addr.s_addr);
			setvar(&ep, prefix, "subnet_mask", inet_ntoa(net));
 }
		i = inet_ntocidr(net);
		snprintf(cidr, sizeof(cidr), "%d", inet_ntocidr(net));
		setvar(&ep, prefix, "subnet_cidr", cidr);
 if (get_option_addr(&brd, dhcp, DHO_BROADCAST) == -1) {
			brd.s_addr = addr.s_addr | ~net.s_addr;
			setvar(&ep, prefix, "broadcast_address", inet_ntoa(brd));
 }
		addr.s_addr = dhcp->yiaddr & net.s_addr;
		setvar(&ep, prefix, "network_number", inet_ntoa(addr));
 }

 if (*dhcp->bootfile && !(overl & 1))
		setvar(&ep, prefix, "filename", (const char *)dhcp->bootfile);
 if (*dhcp->servername && !(overl & 2))
		setvar(&ep, prefix, "server_name", (const char *)dhcp->servername);

 for (opt = dhcp_opts; opt->option; opt++) {
 if (!opt->var)
 continue;
 if (has_option_mask(ifo->nomask, opt->option))
 continue;
		val = NULL;
		p = get_option(dhcp, opt->option, &pl, NULL);
 if (!p)
 continue;
 /* We only want the FQDN name */
 if (opt->option == DHO_FQDN) {
			p += 3;
			pl -= 3;
 }
		len = print_option(NULL, 0, opt->type, pl, p);
 if (len < 0)
 return -1;
		e = strlen(prefix) + strlen(opt->var) + len + 4;
		v = val = *ep++ = xmalloc(e);
		v += snprintf(val, e, "%s_%s=", prefix, opt->var);
 if (len != 0)
			print_option(v, len, opt->type, pl, p);
 }

 return ep - env;
}

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.