HS 2.0: Move Terms and Conditions Server URL generation from AP to AS

This makes it more convenient to generate the URL in a way that
interoperates between different vendors. The AP is simply copying the
already constructed URL as-is from Access-Accept to WNM-Notification.
This means that the HO AAA can generate the URL in a manner that works
for the associated T&C Server without having to coordinate with each AP.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>

hostapd/hostapd.conf

@@ -2191,7 +2191,8 @@ own_ip_addr=127.0.0.1
 #
 # hs20_t_c_server_url contains a template for the Terms and Conditions server
 # URL. This template is used to generate the URL for a STA that needs to
-# acknowledge Terms and Conditions.
+# acknowledge Terms and Conditions. Unlike the other hs20_t_c_* parameters, this
+# parameter is used on the authentication server, not the AP.
 # Macros:
 # @1@ = MAC address of the STA (colon separated hex octets)
 #hs20_t_c_server_url=https://example.com/t_and_c?addr=@1@&ap=123

src/ap/authsrv.c

@@ -136,6 +136,7 @@ static int hostapd_setup_radius_srv(struct hostapd_data *hapd)
 #ifdef CONFIG_HS20
 	srv.subscr_remediation_url = conf->subscr_remediation_url;
 	srv.subscr_remediation_method = conf->subscr_remediation_method;
+	srv.t_c_server_url = conf->t_c_server_url;
 #endif /* CONFIG_HS20 */
 	srv.erp = conf->eap_server_erp;
 	srv.erp_domain = conf->erp_domain;

src/ap/hs20.c

@@ -180,20 +180,24 @@ int hs20_send_wnm_notification_deauth_req(struct hostapd_data *hapd,
 
 
 int hs20_send_wnm_notification_t_c(struct hostapd_data *hapd,
-				   const u8 *addr)
+				   const u8 *addr, const char *url)
 {
 	struct wpabuf *buf;
 	int ret;
-	const char *url = hapd->conf->t_c_server_url, *pos;
-	size_t url_len;
+	size_t url_len = os_strlen(url);
 
-	if (!url)
+	if (!url) {
+		wpa_printf(MSG_INFO, "HS 2.0: No T&C Server URL available");
 		return -1;
-	pos = os_strstr(url, "@1@");
-	if (!pos)
+	}
+
+	if (5 + url_len > 255) {
+		wpa_printf(MSG_INFO,
+			   "HS 2.0: Too long T&C Server URL for WNM-Notification: '%s'",
+			   url);
 		return -1;
+	}
 
-	url_len = os_strlen(url) + ETH_ALEN * 3 - 1 - 3;
 	buf = wpabuf_alloc(4 + 7 + url_len);
 	if (!buf)
 		return -1;
@@ -209,9 +213,7 @@ int hs20_send_wnm_notification_t_c(struct hostapd_data *hapd,
 	wpabuf_put_be24(buf, OUI_WFA);
 	wpabuf_put_u8(buf, HS20_WNM_T_C_ACCEPTANCE);
 	wpabuf_put_u8(buf, url_len);
-	wpabuf_put_data(buf, url, pos - url);
-	wpabuf_printf(buf, MACSTR, MAC2STR(addr));
-	wpabuf_put_str(buf, pos + 3);
+	wpabuf_put_str(buf, url);
 
 	ret = hostapd_drv_send_action(hapd, hapd->iface->freq, 0, addr,
 				      wpabuf_head(buf), wpabuf_len(buf));

src/ap/hs20.h

@@ -19,7 +19,7 @@ int hs20_send_wnm_notification_deauth_req(struct hostapd_data *hapd,
 					  const u8 *addr,
 					  const struct wpabuf *payload);
 int hs20_send_wnm_notification_t_c(struct hostapd_data *hapd,
-				   const u8 *addr);
+				   const u8 *addr, const char *url);
 void hs20_t_c_filtering(struct hostapd_data *hapd, struct sta_info *sta,
 			int enabled);
 

src/ap/ieee802_1x.c

@@ -1635,6 +1635,20 @@ static void ieee802_1x_hs20_t_c_filtering(struct hostapd_data *hapd,
 	hs20_t_c_filtering(hapd, sta, pos[0] & BIT(0));
 }
 
+
+static void ieee802_1x_hs20_t_c_url(struct hostapd_data *hapd,
+				    struct sta_info *sta, u8 *pos, size_t len)
+{
+	os_free(sta->t_c_url);
+	sta->t_c_url = os_malloc(len + 1);
+	if (!sta->t_c_url)
+		return;
+	os_memcpy(sta->t_c_url, pos, len);
+	sta->t_c_url[len] = '\0';
+	wpa_printf(MSG_DEBUG,
+		   "HS 2.0: Terms and Conditions URL %s", sta->t_c_url);
+}
+
 #endif /* CONFIG_HS20 */
 
 
@@ -1685,6 +1699,9 @@ static void ieee802_1x_check_hs20(struct hostapd_data *hapd,
 		case RADIUS_VENDOR_ATTR_WFA_HS20_T_C_FILTERING:
 			ieee802_1x_hs20_t_c_filtering(hapd, sta, pos, sublen);
 			break;
+		case RADIUS_VENDOR_ATTR_WFA_HS20_T_C_URL:
+			ieee802_1x_hs20_t_c_url(hapd, sta, pos, sublen);
+			break;
 		}
 	}
 #endif /* CONFIG_HS20 */
@@ -2767,7 +2784,9 @@ static void ieee802_1x_wnm_notif_send(void *eloop_ctx, void *timeout_ctx)
 		wpa_printf(MSG_DEBUG, "HS 2.0: Send WNM-Notification to "
 			   MACSTR " to indicate Terms and Conditions filtering",
 			   MAC2STR(sta->addr));
-		hs20_send_wnm_notification_t_c(hapd, sta->addr);
+		hs20_send_wnm_notification_t_c(hapd, sta->addr, sta->t_c_url);
+		os_free(sta->t_c_url);
+		sta->t_c_url = NULL;
 	}
 }
 #endif /* CONFIG_HS20 */

src/ap/sta_info.c

@@ -332,6 +332,7 @@ void ap_free_sta(struct hostapd_data *hapd, struct sta_info *sta)
 	os_free(sta->identity);
 	os_free(sta->radius_cui);
 	os_free(sta->remediation_url);
+	os_free(sta->t_c_url);
 	wpabuf_free(sta->hs20_deauth_req);
 	os_free(sta->hs20_session_info_url);
 

src/ap/sta_info.h

@@ -187,6 +187,7 @@ struct sta_info {
 	struct wpabuf *roaming_consortium;
 	u8 remediation_method;
 	char *remediation_url; /* HS 2.0 Subscription Remediation Server URL */
+	char *t_c_url; /* HS 2.0 Terms and Conditions Server URL */
 	struct wpabuf *hs20_deauth_req;
 	char *hs20_session_info_url;
 	int hs20_disassoc_timer;

src/radius/radius.h

@@ -202,6 +202,7 @@ enum {
 	RADIUS_VENDOR_ATTR_WFA_HS20_T_C_FILENAME = 7,
 	RADIUS_VENDOR_ATTR_WFA_HS20_TIMESTAMP = 8,
 	RADIUS_VENDOR_ATTR_WFA_HS20_T_C_FILTERING = 9,
+	RADIUS_VENDOR_ATTR_WFA_HS20_T_C_URL = 10,
 };
 
 #ifdef _MSC_VER

src/radius/radius_server.c

@@ -350,6 +350,8 @@ struct radius_server_data {
 	char *subscr_remediation_url;
 	u8 subscr_remediation_method;
 
+	char *t_c_server_url;
+
 #ifdef CONFIG_SQLITE
 	sqlite3 *db;
 #endif /* CONFIG_SQLITE */
@@ -884,12 +886,56 @@ radius_server_encapsulate_eap(struct radius_server_data *data,
 
 	if (code == RADIUS_CODE_ACCESS_ACCEPT && sess->t_c_filtering) {
 		u8 buf[4] = { 0x01, 0x00, 0x00, 0x00 }; /* E=1 */
+		const char *url = data->t_c_server_url, *pos;
+		char *url2, *end2, *pos2;
+		size_t url_len;
 
 		if (!radius_msg_add_wfa(
 			    msg, RADIUS_VENDOR_ATTR_WFA_HS20_T_C_FILTERING,
 			    buf, sizeof(buf))) {
 			RADIUS_DEBUG("Failed to add WFA-HS20-T-C-Filtering");
+			radius_msg_free(msg);
+			return NULL;
+		}
+
+		if (!url) {
+			RADIUS_DEBUG("No t_c_server_url configured");
+			radius_msg_free(msg);
+			return NULL;
+		}
+
+		pos = os_strstr(url, "@1@");
+		if (!pos) {
+			RADIUS_DEBUG("No @1@ macro in t_c_server_url");
+			radius_msg_free(msg);
+			return NULL;
+		}
+
+		url_len = os_strlen(url) + ETH_ALEN * 3 - 1 - 3;
+		url2 = os_malloc(url_len);
+		if (!url2) {
+			RADIUS_DEBUG("Failed to allocate room for T&C Server URL");
+			os_free(url2);
+			radius_msg_free(msg);
+			return NULL;
 		}
+		pos2 = url2;
+		end2 = url2 + url_len;
+		os_memcpy(pos2, url, pos - url);
+		pos2 += pos - url;
+		os_snprintf(pos2, end2 - pos2, MACSTR, MAC2STR(sess->mac_addr));
+		pos2 += ETH_ALEN * 3 - 1;
+		os_memcpy(pos2, pos + 3, os_strlen(pos + 3));
+		if (!radius_msg_add_wfa(msg,
+					RADIUS_VENDOR_ATTR_WFA_HS20_T_C_URL,
+					(const u8 *) url2, url_len)) {
+			RADIUS_DEBUG("Failed to add WFA-HS20-T-C-URL");
+			os_free(url2);
+			radius_msg_free(msg);
+			return NULL;
+		}
+		os_free(url2);
+
 		radius_srv_hs20_t_c_pending(sess);
 	}
 #endif /* CONFIG_HS20 */
@@ -1894,6 +1940,9 @@ radius_server_init(struct radius_server_conf *conf)
 	}
 	data->subscr_remediation_method = conf->subscr_remediation_method;
 
+	if (conf->t_c_server_url)
+		data->t_c_server_url = os_strdup(conf->t_c_server_url);
+
 #ifdef CONFIG_SQLITE
 	if (conf->sqlite_file) {
 		if (sqlite3_open(conf->sqlite_file, &data->db)) {
@@ -2010,6 +2059,7 @@ void radius_server_deinit(struct radius_server_data *data)
 	os_free(data->dump_msk_file);
 #endif /* CONFIG_RADIUS_TEST */
 	os_free(data->subscr_remediation_url);
+	os_free(data->t_c_server_url);
 
 #ifdef CONFIG_SQLITE
 	if (data->db)

src/radius/radius_server.h

@@ -233,6 +233,8 @@ struct radius_server_conf {
 
 	char *subscr_remediation_url;
 	u8 subscr_remediation_method;
+
+	char *t_c_server_url;
 };