WPS: Add support for NCF password token from AP

The new hostapd ctrl_iface command WPS_NFC_TOKEN can now be used to
manage AP-as-Enrollee operations with NFC password token. WPS/NDEF
parameters to this command can be used to generate a new NFC password
token. enable/disable parameters can be used to enable/disable use of
NFC password token (instead of AP PIN) for external Registrars.

A preconfigured NFS password token can be used by providing its
parameters with new hostapd.conf fields wps_nfc_dev_pw_id,
wps_nfc_dh_pubkey, wps_nfc_dh_privkey, and wps_nfc_dev_pw. This use
will also depend on WPS_NFC_TOKEN enable/disable commands, i.e., the
configured NFS password token is disabled by default.

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

hostapd/config_file.c

@@ -1325,6 +1325,31 @@ fail:
 #endif /* CONFIG_INTERWORKING */
 
 
+#ifdef CONFIG_WPS_NFC
+static struct wpabuf * hostapd_parse_bin(const char *buf)
+{
+	size_t len;
+	struct wpabuf *ret;
+
+	len = os_strlen(buf);
+	if (len & 0x01)
+		return NULL;
+	len /= 2;
+
+	ret = wpabuf_alloc(len);
+	if (ret == NULL)
+		return NULL;
+
+	if (hexstr2bin(buf, wpabuf_put(ret, len), len)) {
+		wpabuf_free(ret);
+		return NULL;
+	}
+
+	return ret;
+}
+#endif /* CONFIG_WPS_NFC */
+
+
 static int hostapd_config_fill(struct hostapd_config *conf,
 			       struct hostapd_bss_config *bss,
 			       char *buf, char *pos, int line)
@@ -2224,6 +2249,25 @@ static int hostapd_config_fill(struct hostapd_config *conf,
 			bss->upc = os_strdup(pos);
 		} else if (os_strcmp(buf, "pbc_in_m1") == 0) {
 			bss->pbc_in_m1 = atoi(pos);
+#ifdef CONFIG_WPS_NFC
+		} else if (os_strcmp(buf, "wps_nfc_dev_pw_id") == 0) {
+			bss->wps_nfc_dev_pw_id = atoi(pos);
+			if (bss->wps_nfc_dev_pw_id < 0x10 ||
+			    bss->wps_nfc_dev_pw_id > 0xffff) {
+				wpa_printf(MSG_ERROR, "Line %d: Invalid "
+					   "wps_nfc_dev_pw_id value", line);
+				errors++;
+			}
+		} else if (os_strcmp(buf, "wps_nfc_dh_pubkey") == 0) {
+			wpabuf_free(bss->wps_nfc_dh_pubkey);
+			bss->wps_nfc_dh_pubkey = hostapd_parse_bin(pos);
+		} else if (os_strcmp(buf, "wps_nfc_dh_privkey") == 0) {
+			wpabuf_free(bss->wps_nfc_dh_privkey);
+			bss->wps_nfc_dh_privkey = hostapd_parse_bin(pos);
+		} else if (os_strcmp(buf, "wps_nfc_dev_pw") == 0) {
+			wpabuf_free(bss->wps_nfc_dev_pw);
+			bss->wps_nfc_dev_pw = hostapd_parse_bin(pos);
+#endif /* CONFIG_WPS_NFC */
 #endif /* CONFIG_WPS */
 #ifdef CONFIG_P2P_MANAGER
 		} else if (os_strcmp(buf, "manage_p2p") == 0) {
@@ -2398,7 +2442,7 @@ struct hostapd_config * hostapd_config_read(const char *fname)
 	struct hostapd_config *conf;
 	struct hostapd_bss_config *bss;
 	FILE *f;
-	char buf[256], *pos;
+	char buf[512], *pos;
 	int line = 0;
 	int errors = 0;
 	size_t i;

hostapd/ctrl_iface.c

@@ -330,6 +330,52 @@ static int hostapd_ctrl_iface_wps_nfc_config_token(struct hostapd_data *hapd,
 
 	return res;
 }
+
+
+static int hostapd_ctrl_iface_wps_nfc_token_gen(struct hostapd_data *hapd,
+						char *reply, size_t max_len,
+						int ndef)
+{
+	struct wpabuf *buf;
+	int res;
+
+	buf = hostapd_wps_nfc_token_gen(hapd, ndef);
+	if (buf == NULL)
+		return -1;
+
+	res = wpa_snprintf_hex_uppercase(reply, max_len, wpabuf_head(buf),
+					 wpabuf_len(buf));
+	reply[res++] = '\n';
+	reply[res] = '\0';
+
+	wpabuf_free(buf);
+
+	return res;
+}
+
+
+static int hostapd_ctrl_iface_wps_nfc_token(struct hostapd_data *hapd,
+					    char *cmd, char *reply,
+					    size_t max_len)
+{
+	if (os_strcmp(cmd, "WPS") == 0)
+		return hostapd_ctrl_iface_wps_nfc_token_gen(hapd, reply,
+							    max_len, 0);
+
+	if (os_strcmp(cmd, "NDEF") == 0)
+		return hostapd_ctrl_iface_wps_nfc_token_gen(hapd, reply,
+							    max_len, 1);
+
+	if (os_strcmp(cmd, "enable") == 0)
+		return hostapd_wps_nfc_token_enable(hapd);
+
+	if (os_strcmp(cmd, "disable") == 0) {
+		hostapd_wps_nfc_token_disable(hapd);
+		return 0;
+	}
+
+	return -1;
+}
 #endif /* CONFIG_WPS_NFC */
 
 
@@ -835,6 +881,9 @@ static void hostapd_ctrl_iface_receive(int sock, void *eloop_ctx,
 	} else if (os_strncmp(buf, "WPS_NFC_CONFIG_TOKEN ", 21) == 0) {
 		reply_len = hostapd_ctrl_iface_wps_nfc_config_token(
 			hapd, buf + 21, reply, reply_size);
+	} else if (os_strncmp(buf, "WPS_NFC_TOKEN ", 14) == 0) {
+		reply_len = hostapd_ctrl_iface_wps_nfc_token(
+			hapd, buf + 14, reply, reply_size);
 #endif /* CONFIG_WPS_NFC */
 #endif /* CONFIG_WPS */
 	} else if (os_strncmp(buf, "ESS_DISASSOC ", 13) == 0) {

hostapd/hostapd_cli.c

@@ -77,6 +77,7 @@ static const char *commands_help =
 #ifdef CONFIG_WPS_NFC
 "   wps_nfc_tag_read <hexdump>  report read NFC tag with WPS data\n"
 "   wps_nfc_config_token <WPS/NDEF>  build NFC configuration token\n"
+"   wps_nfc_token <WPS/NDEF/enable/disable>  manager NFC password token\n"
 #endif /* CONFIG_WPS_NFC */
 "   wps_ap_pin <cmd> [params..]  enable/disable AP PIN\n"
 "   wps_config <SSID> <auth> <encr> <key>  configure AP\n"
@@ -484,6 +485,27 @@ static int hostapd_cli_cmd_wps_nfc_config_token(struct wpa_ctrl *ctrl,
 	}
 	return wpa_ctrl_command(ctrl, cmd);
 }
+
+
+static int hostapd_cli_cmd_wps_nfc_token(struct wpa_ctrl *ctrl,
+					 int argc, char *argv[])
+{
+	char cmd[64];
+	int res;
+
+	if (argc != 1) {
+		printf("Invalid 'wps_nfc_token' command - one argument is "
+		       "required.\n");
+		return -1;
+	}
+
+	res = os_snprintf(cmd, sizeof(cmd), "WPS_NFC_TOKEN %s", argv[0]);
+	if (res < 0 || (size_t) res >= sizeof(cmd) - 1) {
+		printf("Too long WPS_NFC_TOKEN command.\n");
+		return -1;
+	}
+	return wpa_ctrl_command(ctrl, cmd);
+}
 #endif /* CONFIG_WPS_NFC */
 
 
@@ -787,6 +809,7 @@ static struct hostapd_cli_cmd hostapd_cli_commands[] = {
 #ifdef CONFIG_WPS_NFC
 	{ "wps_nfc_tag_read", hostapd_cli_cmd_wps_nfc_tag_read },
 	{ "wps_nfc_config_token", hostapd_cli_cmd_wps_nfc_config_token },
+	{ "wps_nfc_token", hostapd_cli_cmd_wps_nfc_token },
 #endif /* CONFIG_WPS_NFC */
 	{ "wps_ap_pin", hostapd_cli_cmd_wps_ap_pin },
 	{ "wps_config", hostapd_cli_cmd_wps_config },

src/ap/ap_config.c

@@ -491,6 +491,9 @@ static void hostapd_config_free_bss(struct hostapd_bss_config *conf)
 	os_free(conf->model_description);
 	os_free(conf->model_url);
 	os_free(conf->upc);
+	wpabuf_free(conf->wps_nfc_dh_pubkey);
+	wpabuf_free(conf->wps_nfc_dh_privkey);
+	wpabuf_free(conf->wps_nfc_dev_pw);
 #endif /* CONFIG_WPS */
 
 	os_free(conf->roaming_consortium);

src/ap/ap_config.h

@@ -344,6 +344,10 @@ struct hostapd_bss_config {
 	char *model_url;
 	char *upc;
 	struct wpabuf *wps_vendor_ext[MAX_WPS_VENDOR_EXTENSIONS];
+	int wps_nfc_dev_pw_id;
+	struct wpabuf *wps_nfc_dh_pubkey;
+	struct wpabuf *wps_nfc_dh_privkey;
+	struct wpabuf *wps_nfc_dev_pw;
 #endif /* CONFIG_WPS */
 	int pbc_in_m1;
 

src/ap/wps_hostapd.c

@@ -12,6 +12,8 @@
 #include "utils/eloop.h"
 #include "utils/uuid.h"
 #include "crypto/dh_groups.h"
+#include "crypto/dh_group5.h"
+#include "crypto/random.h"
 #include "common/wpa_ctrl.h"
 #include "common/ieee802_11_defs.h"
 #include "common/ieee802_11_common.h"
@@ -992,6 +994,20 @@ int hostapd_init_wps_complete(struct hostapd_data *hapd)
 }
 
 
+static void hostapd_wps_nfc_clear(struct wps_context *wps)
+{
+#ifdef CONFIG_WPS_NFC
+	wps->ap_nfc_dev_pw_id = 0;
+	wpabuf_free(wps->ap_nfc_dh_pubkey);
+	wps->ap_nfc_dh_pubkey = NULL;
+	wpabuf_free(wps->ap_nfc_dh_privkey);
+	wps->ap_nfc_dh_privkey = NULL;
+	wpabuf_free(wps->ap_nfc_dev_pw);
+	wps->ap_nfc_dev_pw = NULL;
+#endif /* CONFIG_WPS_NFC */
+}
+
+
 void hostapd_deinit_wps(struct hostapd_data *hapd)
 {
 	eloop_cancel_timeout(hostapd_wps_reenable_ap_pin, hapd, NULL);
@@ -1009,6 +1025,7 @@ void hostapd_deinit_wps(struct hostapd_data *hapd)
 	wpabuf_free(hapd->wps->oob_conf.pubkey_hash);
 	wpabuf_free(hapd->wps->oob_conf.dev_password);
 	wps_free_pending_msgs(hapd->wps->upnp_msgs);
+	hostapd_wps_nfc_clear(hapd->wps);
 	os_free(hapd->wps);
 	hapd->wps = NULL;
 	hostapd_wps_clear_ies(hapd);
@@ -1606,4 +1623,86 @@ struct wpabuf * hostapd_wps_nfc_config_token(struct hostapd_data *hapd,
 	return ret;
 }
 
+
+struct wpabuf * hostapd_wps_nfc_token_gen(struct hostapd_data *hapd, int ndef)
+{
+	struct wpabuf *priv = NULL, *pub = NULL, *pw;
+	void *dh_ctx;
+	struct wpabuf *ret;
+
+	pw = wpabuf_alloc(WPS_OOB_DEVICE_PASSWORD_LEN);
+	if (pw == NULL)
+		return NULL;
+
+	if (random_get_bytes(wpabuf_put(pw, WPS_OOB_DEVICE_PASSWORD_LEN),
+			     WPS_OOB_DEVICE_PASSWORD_LEN)) {
+		wpabuf_free(pw);
+		return NULL;
+	}
+
+	dh_ctx = dh5_init(&priv, &pub);
+	if (dh_ctx == NULL) {
+		wpabuf_free(pw);
+		return NULL;
+	}
+	dh5_free(dh_ctx);
+
+	hapd->conf->wps_nfc_dev_pw_id = 0x10 + os_random() % 0xfff0;
+	wpabuf_free(hapd->conf->wps_nfc_dh_pubkey);
+	hapd->conf->wps_nfc_dh_pubkey = pub;
+	wpabuf_free(hapd->conf->wps_nfc_dh_privkey);
+	hapd->conf->wps_nfc_dh_privkey = priv;
+	wpabuf_free(hapd->conf->wps_nfc_dev_pw);
+	hapd->conf->wps_nfc_dev_pw = pw;
+
+	ret = wps_build_nfc_pw_token(hapd->conf->wps_nfc_dev_pw_id,
+				     hapd->conf->wps_nfc_dh_pubkey,
+				     hapd->conf->wps_nfc_dev_pw);
+	if (ndef && ret) {
+		struct wpabuf *tmp;
+		tmp = ndef_build_wifi(ret);
+		wpabuf_free(ret);
+		if (tmp == NULL)
+			return NULL;
+		ret = tmp;
+	}
+
+	return ret;
+}
+
+
+int hostapd_wps_nfc_token_enable(struct hostapd_data *hapd)
+{
+	struct wps_context *wps = hapd->wps;
+
+	if (wps == NULL)
+		return -1;
+
+	if (!hapd->conf->wps_nfc_dh_pubkey ||
+	    !hapd->conf->wps_nfc_dh_privkey ||
+	    !hapd->conf->wps_nfc_dev_pw ||
+	    !hapd->conf->wps_nfc_dev_pw_id)
+		return -1;
+
+	hostapd_wps_nfc_clear(wps);
+	wps->ap_nfc_dev_pw_id = hapd->conf->wps_nfc_dev_pw_id;
+	wps->ap_nfc_dh_pubkey = wpabuf_dup(hapd->conf->wps_nfc_dh_pubkey);
+	wps->ap_nfc_dh_privkey = wpabuf_dup(hapd->conf->wps_nfc_dh_privkey);
+	wps->ap_nfc_dev_pw = wpabuf_dup(hapd->conf->wps_nfc_dev_pw);
+
+	if (!wps->ap_nfc_dh_pubkey || !wps->ap_nfc_dh_privkey ||
+	    !wps->ap_nfc_dev_pw) {
+		hostapd_wps_nfc_clear(wps);
+		return -1;
+	}
+
+	return 0;
+}
+
+
+void hostapd_wps_nfc_token_disable(struct hostapd_data *hapd)
+{
+	hostapd_wps_nfc_clear(hapd->wps);
+}
+
 #endif /* CONFIG_WPS_NFC */

src/ap/wps_hostapd.h

@@ -37,6 +37,9 @@ int hostapd_wps_nfc_tag_read(struct hostapd_data *hapd,
 			     const struct wpabuf *data);
 struct wpabuf * hostapd_wps_nfc_config_token(struct hostapd_data *hapd,
 					     int ndef);
+struct wpabuf * hostapd_wps_nfc_token_gen(struct hostapd_data *hapd, int ndef);
+int hostapd_wps_nfc_token_enable(struct hostapd_data *hapd);
+void hostapd_wps_nfc_token_disable(struct hostapd_data *hapd);
 
 #else /* CONFIG_WPS */
 

src/wps/wps.c

@@ -56,6 +56,23 @@ struct wps_data * wps_init(const struct wps_config *cfg)
 		data->dev_password_len = cfg->pin_len;
 	}
 
+#ifdef CONFIG_WPS_NFC
+	if (cfg->wps->ap && !cfg->registrar && cfg->wps->ap_nfc_dev_pw_id) {
+		data->dev_pw_id = cfg->wps->ap_nfc_dev_pw_id;
+		os_free(data->dev_password);
+		data->dev_password =
+			os_malloc(wpabuf_len(cfg->wps->ap_nfc_dev_pw));
+		if (data->dev_password == NULL) {
+			os_free(data);
+			return NULL;
+		}
+		os_memcpy(data->dev_password,
+			  wpabuf_head(cfg->wps->ap_nfc_dev_pw),
+			  wpabuf_len(cfg->wps->ap_nfc_dev_pw));
+		data->dev_password_len = wpabuf_len(cfg->wps->ap_nfc_dev_pw);
+	}
+#endif /* CONFIG_WPS_NFC */
+
 	data->pbc = cfg->pbc;
 	if (cfg->pbc) {
 		/* Use special PIN '00000000' for PBC */

src/wps/wps.h

@@ -757,6 +757,11 @@ struct wps_context {
 
 	/* Pending messages from UPnP PutWLANResponse */
 	struct upnp_pending_message *upnp_msgs;
+
+	u16 ap_nfc_dev_pw_id;
+	struct wpabuf *ap_nfc_dh_pubkey;
+	struct wpabuf *ap_nfc_dh_privkey;
+	struct wpabuf *ap_nfc_dev_pw;
 };
 
 struct oob_device_data {

src/wps/wps_attr_build.c

@@ -30,6 +30,14 @@ int wps_build_public_key(struct wps_data *wps, struct wpabuf *msg)
 		wps->dh_ctx = wps->wps->dh_ctx;
 		wps->wps->dh_ctx = NULL;
 		pubkey = wpabuf_dup(wps->wps->dh_pubkey);
+#ifdef CONFIG_WPS_NFC
+	} else if (wps->dev_pw_id >= 0x10 && wps->wps->ap &&
+		   wps->dev_pw_id == wps->wps->ap_nfc_dev_pw_id) {
+		wpa_printf(MSG_DEBUG, "WPS: Using NFC password token DH keys");
+		wps->dh_privkey = wpabuf_dup(wps->wps->ap_nfc_dh_privkey);
+		pubkey = wpabuf_dup(wps->wps->ap_nfc_dh_pubkey);
+		wps->dh_ctx = dh5_init_fixed(wps->dh_privkey, pubkey);
+#endif /* CONFIG_WPS_NFC */
 	} else {
 		wpa_printf(MSG_DEBUG, "WPS: Generate new DH keys");
 		wps->dh_privkey = NULL;