WPS: Generate UUID based on MAC address, if not set

Generate a SHA1 hash -based UUID from the local MAC address if the UUID
was not configured. This makes it easier to prepare for WPS since there
is no need to generate an UUID.

hostapd/README-WPS

@@ -94,6 +94,7 @@ eap_server=1
 # WPS configuration (AP configured, do not allow external WPS Registrars)
 wps_state=2
 ap_setup_locked=1
+# If UUID is not configured, it will be generated based on local MAC address.
 uuid=87654321-9abc-def0-1234-56789abc0000
 wps_pin_requests=/var/run/hostapd.pin-req
 device_name=Wireless AP

hostapd/hostapd.conf

@@ -871,6 +871,7 @@ own_ip_addr=127.0.0.1
 # Universally Unique IDentifier (UUID; see RFC 4122) of the device
 # This value is used as the UUID for the internal WPS Registrar. If the AP
 # is also using UPnP, this value should be set to the device's UPnP UUID.
+# If not configured, UUID will be generated based on the local MAC address.
 #uuid=12345678-9abc-def0-1234-56789abcdef0
 
 # Note: If wpa_psk_file is set, WPS is used to generate random, per-device PSKs

hostapd/wps_hostapd.c

@@ -383,6 +383,11 @@ int hostapd_init_wps(struct hostapd_data *hapd,
 	os_memset(&cfg, 0, sizeof(cfg));
 	wps->wps_state = hapd->conf->wps_state;
 	wps->ap_setup_locked = hapd->conf->ap_setup_locked;
+	if (is_nil_uuid(hapd->conf->uuid)) {
+		uuid_gen_mac_addr(hapd->own_addr, wps->uuid);
+		wpa_hexdump(MSG_DEBUG, "WPS: UUID based on MAC address",
+			    wps->uuid, UUID_LEN);
+	} else
 		os_memcpy(wps->uuid, hapd->conf->uuid, UUID_LEN);
 	wps->ssid_len = hapd->conf->ssid.ssid_len;
 	os_memcpy(wps->ssid, hapd->conf->ssid.ssid, wps->ssid_len);

src/utils/uuid.c

@@ -15,6 +15,8 @@
 #include "includes.h"
 
 #include "common.h"
+#include "crypto.h"
+#include "sha1.h"
 #include "uuid.h"
 
 int uuid_str2bin(const char *str, u8 *bin)
@@ -75,3 +77,31 @@ int is_nil_uuid(const u8 *uuid)
 			return 0;
 	return 1;
 }
+
+
+void uuid_gen_mac_addr(const u8 *mac_addr, u8 *uuid)
+{
+	const u8 *addr[2];
+	size_t len[2];
+	u8 hash[SHA1_MAC_LEN];
+	u8 nsid[16] = {
+		0x52, 0x64, 0x80, 0xf8,
+		0xc9, 0x9b,
+		0x4b, 0xe5,
+		0xa6, 0x55,
+		0x58, 0xed, 0x5f, 0x5d, 0x60, 0x84
+	};
+
+	addr[0] = nsid;
+	len[0] = sizeof(nsid);
+	addr[1] = mac_addr;
+	len[1] = 6;
+	sha1_vector(2, addr, len, hash);
+	os_memcpy(uuid, hash, 16);
+
+	/* Version: 5 = named-based version using SHA-1 */
+	uuid[6] = (5 << 4) | (uuid[6] & 0x0f);
+
+	/* Variant specified in RFC 4122 */
+	uuid[8] = 0x80 | (uuid[8] & 0x3f);
+}

src/utils/uuid.h

@@ -20,5 +20,6 @@
 int uuid_str2bin(const char *str, u8 *bin);
 int uuid_bin2str(const u8 *bin, char *str, size_t max_len);
 int is_nil_uuid(const u8 *uuid);
+void uuid_gen_mac_addr(const u8 *mac_addr, u8 *uuid);
 
 #endif /* UUID_H */

wpa_supplicant/README-WPS

@@ -67,7 +67,8 @@ CONFIG_WPS=y
 
 WPS needs the Universally Unique IDentifier (UUID; see RFC 4122) for
 the device. This is configured in the runtime configuration for
-wpa_supplicant:
+wpa_supplicant (if not set, UUID will be generated based on local MAC
+address):
 
 # example UUID for WPS
 uuid=12345678-9abc-def0-1234-56789abcdef0

wpa_supplicant/scan.c

@@ -181,7 +181,7 @@ static void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
 #ifdef CONFIG_WPS
 	if (wps) {
 		wps_ie = wps_build_probe_req_ie(wps == 2, &wpa_s->wps->dev,
-						wpa_s->conf->uuid, req_type);
+						wpa_s->wps->uuid, req_type);
 		if (wps_ie) {
 			extra_ie = wpabuf_head(wps_ie);
 			extra_ie_len = wpabuf_len(wps_ie);

wpa_supplicant/wpa_supplicant.conf

@@ -150,6 +150,7 @@ fast_reauth=1
 # Wi-Fi Protected Setup (WPS) parameters
 
 # Universally Unique IDentifier (UUID; see RFC 4122) of the device
+# If not configured, UUID will be generated based on the local MAC address.
 #uuid=12345678-9abc-def0-1234-56789abcdef0
 
 # Device Name

wpa_supplicant/wps_supplicant.c

@@ -21,6 +21,7 @@
 #include "eap_peer/eap.h"
 #include "wpa_supplicant_i.h"
 #include "eloop.h"
+#include "uuid.h"
 #include "wpa_ctrl.h"
 #include "eap_common/eap_wsc_common.h"
 #include "wps/wps.h"
@@ -442,7 +443,12 @@ int wpas_wps_init(struct wpa_supplicant *wpa_s)
 	wps->dev.os_version = WPA_GET_BE32(wpa_s->conf->os_version);
 	wps->dev.rf_bands = WPS_RF_24GHZ | WPS_RF_50GHZ; /* TODO: config */
 	os_memcpy(wps->dev.mac_addr, wpa_s->own_addr, ETH_ALEN);
-	os_memcpy(wps->uuid, wpa_s->conf->uuid, 16);
+	if (is_nil_uuid(wpa_s->conf->uuid)) {
+		uuid_gen_mac_addr(wpa_s->own_addr, wps->uuid);
+		wpa_hexdump(MSG_DEBUG, "WPS: UUID based on MAC address",
+			    wps->uuid, WPS_UUID_LEN);
+	} else
+		os_memcpy(wps->uuid, wpa_s->conf->uuid, WPS_UUID_LEN);
 
 	wpa_s->wps = wps;