WPS: Parse Request Type from WPS IE in (Re)AssocReq and derive mgmt keys

WPS IE is now passed from hostapd association processing into EAP-WSC
and WPS processing. Request Type attribute is parsed from this
information and if the request is for a WLAN Manager Registrar,
additional management keys are derived (to be used with UPnP).

hostapd/ap.h

@@ -103,6 +103,8 @@ struct sta_info {
 	u8 *ping_trans_id; /* buffer of WLAN_PING_TRANS_ID_LEN * ping_count
 			    * octets of pending ping transaction identifiers */
 #endif /* CONFIG_IEEE80211W */
+
+	struct wpabuf *wps_ie; /* WPS IE from (Re)Association Request */
 };
 
 

hostapd/eapol_sm.c

@@ -813,6 +813,7 @@ eapol_auth_alloc(struct eapol_authenticator *eapol, const u8 *addr,
 	eap_conf.eap_sim_aka_result_ind = eapol->conf.eap_sim_aka_result_ind;
 	eap_conf.tnc = eapol->conf.tnc;
 	eap_conf.wps = eapol->conf.wps;
+	eap_conf.assoc_wps_ie = sta->wps_ie;
 	sm->eap = eap_server_sm_init(sm, &eapol_cb, &eap_conf);
 	if (sm->eap == NULL) {
 		eapol_auth_free(sm);

hostapd/ieee802_11.c

@@ -839,6 +839,9 @@ static void handle_assoc(struct hostapd_data *hapd,
 				   "(Re)Association Request - assume WPS is "
 				   "used");
 			sta->flags |= WLAN_STA_WPS;
+			wpabuf_free(sta->wps_ie);
+			sta->wps_ie = wpabuf_alloc_copy(elems.wps_ie + 4,
+							elems.wps_ie_len - 4);
 		} else {
 			wpa_printf(MSG_DEBUG, "STA did not include WPA/RSN IE "
 				   "in (Re)Association Request - possible WPS "

hostapd/sta_info.c

@@ -188,6 +188,8 @@ void ap_free_sta(struct hostapd_data *hapd, struct sta_info *sta)
 	eloop_cancel_timeout(ap_ping_timer, hapd, sta);
 #endif /* CONFIG_IEEE80211W */
 
+	wpabuf_free(sta->wps_ie);
+
 	os_free(sta);
 }
 

src/eap_server/eap.c

@@ -1167,6 +1167,8 @@ struct eap_sm * eap_server_sm_init(void *eapol_ctx,
 	sm->eap_sim_aka_result_ind = conf->eap_sim_aka_result_ind;
 	sm->tnc = conf->tnc;
 	sm->wps = conf->wps;
+	if (conf->assoc_wps_ie)
+		sm->assoc_wps_ie = wpabuf_dup(conf->assoc_wps_ie);
 
 	wpa_printf(MSG_DEBUG, "EAP: Server state machine created");
 
@@ -1200,6 +1202,7 @@ void eap_server_sm_deinit(struct eap_sm *sm)
 	wpabuf_free(sm->eap_if.aaaEapRespData);
 	os_free(sm->eap_if.aaaEapKeyData);
 	eap_user_free(sm->user);
+	wpabuf_free(sm->assoc_wps_ie);
 	os_free(sm);
 }
 

src/eap_server/eap.h

@@ -104,6 +104,7 @@ struct eap_config {
 	int eap_sim_aka_result_ind;
 	int tnc;
 	struct wps_context *wps;
+	const struct wpabuf *assoc_wps_ie;
 };
 
 

src/eap_server/eap_i.h

@@ -182,6 +182,7 @@ struct eap_sm {
 	int eap_sim_aka_result_ind;
 	int tnc;
 	struct wps_context *wps;
+	struct wpabuf *assoc_wps_ie;
 };
 
 int eap_user_get(struct eap_sm *sm, const u8 *identity, size_t identity_len,

src/eap_server/eap_wsc.c

@@ -1,6 +1,6 @@
 /*
  * EAP-WSC server for Wi-Fi Protected Setup
- * Copyright (c) 2007, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2007-2008, Jouni Malinen <j@w1.fi>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -109,6 +109,7 @@ static void * eap_wsc_init(struct eap_sm *sm)
 		cfg.pin = sm->user->password;
 		cfg.pin_len = sm->user->password_len;
 	}
+	cfg.assoc_wps_ie = sm->assoc_wps_ie;
 	data->wps = wps_init(&cfg);
 	if (data->wps == NULL) {
 		os_free(data);

src/wps/wps.c

@@ -60,6 +60,24 @@ struct wps_data * wps_init(const struct wps_config *cfg)
 
 	data->state = data->registrar ? RECV_M1 : SEND_M1;
 
+	if (cfg->assoc_wps_ie) {
+		struct wps_parse_attr attr;
+		wpa_hexdump_buf(MSG_DEBUG, "WPS: WPS IE from (Re)AssocReq",
+				cfg->assoc_wps_ie);
+		if (wps_parse_msg(cfg->assoc_wps_ie, &attr) < 0) {
+			wpa_printf(MSG_DEBUG, "WPS: Failed to parse WPS IE "
+				   "from (Re)AssocReq");
+		} else if (attr.request_type == NULL) {
+			wpa_printf(MSG_DEBUG, "WPS: No Request Type attribute "
+				   "in (Re)AssocReq WPS IE");
+		} else {
+			wpa_printf(MSG_DEBUG, "WPS: Request Type (from WPS IE "
+				   "in (Re)AssocReq WPS IE): %d",
+				   *attr.request_type);
+			data->request_type = *attr.request_type;
+		}
+	}
+
 	return data;
 }
 

src/wps/wps.h

@@ -47,6 +47,7 @@ struct wps_config {
 	size_t pin_len;
 	const u8 *uuid; /* 128-bit Enrollee UUID (NULL for Registrar) */
 	int pbc;
+	const struct wpabuf *assoc_wps_ie; /* (Re)AssocReq WPS IE (in AP) */
 };
 
 struct wps_data * wps_init(const struct wps_config *cfg);

src/wps/wps_common.c

@@ -433,11 +433,12 @@ int wps_parse_msg(const struct wpabuf *msg, struct wps_parse_attr *attr)
 }
 
 
-void wps_kdf(const u8 *key, const char *label, u8 *res, size_t res_len)
+void wps_kdf(const u8 *key, const u8 *label_prefix, size_t label_prefix_len,
+	     const char *label, u8 *res, size_t res_len)
 {
 	u8 i_buf[4], key_bits[4];
-	const u8 *addr[3];
-	size_t len[3];
+	const u8 *addr[4];
+	size_t len[4];
 	int i, iter;
 	u8 hash[SHA256_MAC_LEN], *opos;
 	size_t left;
@@ -446,10 +447,12 @@ void wps_kdf(const u8 *key, const char *label, u8 *res, size_t res_len)
 
 	addr[0] = i_buf;
 	len[0] = sizeof(i_buf);
-	addr[1] = (const u8 *) label;
-	len[1] = os_strlen(label);
-	addr[2] = key_bits;
-	len[2] = sizeof(key_bits);
+	addr[1] = label_prefix;
+	len[1] = label_prefix_len;
+	addr[2] = (const u8 *) label;
+	len[2] = os_strlen(label);
+	addr[3] = key_bits;
+	len[3] = sizeof(key_bits);
 
 	iter = (res_len + SHA256_MAC_LEN - 1) / SHA256_MAC_LEN;
 	opos = res;
@@ -457,7 +460,7 @@ void wps_kdf(const u8 *key, const char *label, u8 *res, size_t res_len)
 
 	for (i = 1; i <= iter; i++) {
 		WPA_PUT_BE32(i_buf, i);
-		hmac_sha256_vector(key, SHA256_MAC_LEN, 3, addr, len, hash);
+		hmac_sha256_vector(key, SHA256_MAC_LEN, 4, addr, len, hash);
 		if (i < iter) {
 			os_memcpy(opos, hash, SHA256_MAC_LEN);
 			opos += SHA256_MAC_LEN;
@@ -545,7 +548,7 @@ int wps_derive_keys(struct wps_data *wps)
 	hmac_sha256_vector(dhkey, sizeof(dhkey), 3, addr, len, kdk);
 	wpa_hexdump_key(MSG_DEBUG, "WPS: KDK", kdk, sizeof(kdk));
 
-	wps_kdf(kdk, "Wi-Fi Easy and Secure Key Derivation",
+	wps_kdf(kdk, NULL, 0, "Wi-Fi Easy and Secure Key Derivation",
 		keys, sizeof(keys));
 	os_memcpy(wps->authkey, keys, WPS_AUTHKEY_LEN);
 	os_memcpy(wps->keywrapkey, keys + WPS_AUTHKEY_LEN, WPS_KEYWRAPKEY_LEN);
@@ -562,6 +565,56 @@ int wps_derive_keys(struct wps_data *wps)
 }
 
 
+int wps_derive_mgmt_keys(struct wps_data *wps)
+{
+	u8 nonces[2 * WPS_NONCE_LEN];
+	u8 keys[WPS_MGMTAUTHKEY_LEN + WPS_MGMTENCKEY_LEN];
+	u8 hash[SHA256_MAC_LEN];
+	const u8 *addr[2];
+	size_t len[2];
+	const char *auth_label = "WFA-WLAN-Management-MgmtAuthKey";
+	const char *enc_label = "WFA-WLAN-Management-MgmtEncKey";
+
+	/* MgmtAuthKey || MgmtEncKey =
+	 * kdf(EMSK, N1 || N2 || "WFA-WLAN-Management-Keys", 384) */
+	os_memcpy(nonces, wps->nonce_e, WPS_NONCE_LEN);
+	os_memcpy(nonces + WPS_NONCE_LEN, wps->nonce_r, WPS_NONCE_LEN);
+	wps_kdf(wps->emsk, nonces, sizeof(nonces), "WFA-WLAN-Management-Keys",
+		keys, sizeof(keys));
+	os_memcpy(wps->mgmt_auth_key, keys, WPS_MGMTAUTHKEY_LEN);
+	os_memcpy(wps->mgmt_enc_key, keys + WPS_MGMTAUTHKEY_LEN,
+		  WPS_MGMTENCKEY_LEN);
+
+	addr[0] = nonces;
+	len[0] = sizeof(nonces);
+
+	/* MgmtEncKeyID = first 128 bits of
+	 * SHA-256(N1 || N2 || "WFA-WLAN-Management-MgmtAuthKey") */
+	addr[1] = (const u8 *) auth_label;
+	len[1] = os_strlen(auth_label);
+	sha256_vector(2, addr, len, hash);
+	os_memcpy(wps->mgmt_auth_key_id, hash, WPS_MGMT_KEY_ID_LEN);
+
+	/* MgmtEncKeyID = first 128 bits of
+	 * SHA-256(N1 || N2 || "WFA-WLAN-Management-MgmtEncKey") */
+	addr[1] = (const u8 *) enc_label;
+	len[1] = os_strlen(enc_label);
+	sha256_vector(2, addr, len, hash);
+	os_memcpy(wps->mgmt_enc_key_id, hash, WPS_MGMT_KEY_ID_LEN);
+
+	wpa_hexdump_key(MSG_DEBUG, "WPS: MgmtAuthKey",
+			wps->mgmt_auth_key, WPS_MGMTAUTHKEY_LEN);
+	wpa_hexdump(MSG_DEBUG, "WPS: MgmtAuthKeyID",
+		    wps->mgmt_auth_key_id, WPS_MGMT_KEY_ID_LEN);
+	wpa_hexdump_key(MSG_DEBUG, "WPS: MgmtEncKey",
+			wps->mgmt_enc_key, WPS_MGMTENCKEY_LEN);
+	wpa_hexdump(MSG_DEBUG, "WPS: MgmtEncKeyID",
+		    wps->mgmt_enc_key_id, WPS_MGMT_KEY_ID_LEN);
+
+	return 0;
+}
+
+
 int wps_build_authenticator(struct wps_data *wps, struct wpabuf *msg)
 {
 	u8 hash[SHA256_MAC_LEN];

src/wps/wps_defs.h

@@ -30,6 +30,9 @@
 #define WPS_SECRET_NONCE_LEN 16
 #define WPS_HASH_LEN 32
 #define WPS_KWA_LEN 8
+#define WPS_MGMTAUTHKEY_LEN 32
+#define WPS_MGMTENCKEY_LEN 16
+#define WPS_MGMT_KEY_ID_LEN 16
 
 /* Attribute Types */
 enum wps_attribute {

src/wps/wps_enrollee.c

@@ -553,7 +553,14 @@ static int wps_process_pubkey(struct wps_data *wps, const u8 *pk,
 	if (wps->dh_pubkey_r == NULL)
 		return -1;
 
-	return wps_derive_keys(wps);
+	if (wps_derive_keys(wps) < 0)
+		return -1;
+
+	if (wps->request_type == WPS_REQ_WLAN_MANAGER_REGISTRAR &&
+	    wps_derive_mgmt_keys(wps) < 0)
+		return -1;
+
+	return 0;
 }
 
 

src/wps/wps_i.h

@@ -56,6 +56,10 @@ struct wps_data {
 	u8 authkey[WPS_AUTHKEY_LEN];
 	u8 keywrapkey[WPS_KEYWRAPKEY_LEN];
 	u8 emsk[WPS_EMSK_LEN];
+	u8 mgmt_auth_key[WPS_MGMTAUTHKEY_LEN];
+	u8 mgmt_auth_key_id[WPS_MGMT_KEY_ID_LEN];
+	u8 mgmt_enc_key[WPS_MGMTENCKEY_LEN];
+	u8 mgmt_enc_key_id[WPS_MGMT_KEY_ID_LEN];
 
 	struct wpabuf *last_msg;
 
@@ -63,6 +67,7 @@ struct wps_data {
 	size_t dev_password_len;
 	u16 dev_pw_id;
 	int pbc;
+	u8 request_type; /* Request Type attribute from (Re)AssocReq */
 
 	u16 encr_type; /* available encryption types */
 	u16 auth_type; /* available authentication types */
@@ -151,9 +156,11 @@ struct wps_parse_attr {
 
 /* wps_common.c */
 int wps_parse_msg(const struct wpabuf *msg, struct wps_parse_attr *attr);
-void wps_kdf(const u8 *key, const char *label, u8 *res, size_t res_len);
+void wps_kdf(const u8 *key, const u8 *label_prefix, size_t label_prefix_len,
+	     const char *label, u8 *res, size_t res_len);
 int wps_build_public_key(struct wps_data *wps, struct wpabuf *msg);
 int wps_derive_keys(struct wps_data *wps);
+int wps_derive_mgmt_keys(struct wps_data *wps);
 int wps_build_authenticator(struct wps_data *wps, struct wpabuf *msg);
 int wps_process_authenticator(struct wps_data *wps, const u8 *authenticator,
 			      const struct wpabuf *msg);