WNM: Ignore Key Data in WNM Sleep Mode Response frame if no PMF in use

WNM Sleep Mode Response frame is used to update GTK/IGTK only if PMF is
enabled. Verify that PMF is in use before using this field on station
side to avoid accepting unauthenticated key updates. (CVE-2015-5310)

Signed-off-by: Jouni Malinen <j@w1.fi>

wpa_supplicant/wnm_sta.c

@@ -189,6 +189,12 @@ static void wnm_sleep_mode_exit_success(struct wpa_supplicant *wpa_s,
 	end = ptr + key_len_total;
 	wpa_hexdump_key(MSG_DEBUG, "WNM: Key Data", ptr, key_len_total);
 
+	if (key_len_total && !wpa_sm_pmf_enabled(wpa_s->wpa)) {
+		wpa_msg(wpa_s, MSG_INFO,
+			"WNM: Ignore Key Data in WNM-Sleep Mode Response - PMF not enabled");
+		return;
+	}
+
 	while (end - ptr > 1) {
 		if (2 + ptr[1] > end - ptr) {
 			wpa_printf(MSG_DEBUG, "WNM: Invalid Key Data element "