ERP server: Make erp_send_finish_reauth() easier for static analyzers

The flags argument is used to indicate a failure case (0x80) which
allows erp == NULL. This may be a bit too difficult combination for
static analyzers to understand, so add an explicit check for !erp as
another condition for returning from the function before the erp pointer
gets dereferenced without checking it.

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

src/eap_server/eap_server.c

@@ -745,7 +745,7 @@ static void erp_send_finish_reauth(struct eap_sm *sm,
 	wpabuf_free(sm->lastReqData);
 	sm->lastReqData = NULL;
 
-	if (flags & 0x80) {
+	if ((flags & 0x80) || !erp) {
 		sm->eap_if.eapFail = TRUE;
 		wpa_msg(sm->msg_ctx, MSG_INFO, WPA_EVENT_EAP_FAILURE
 			MACSTR, MAC2STR(sm->peer_addr));