EAP peer: Add Session-Id derivation

This adds a new getSessionId() callback for EAP peer methods to allow
EAP Session-Id to be derived. This commits implements this for EAP-FAST,
EAP-GPSK, EAP-IKEv2, EAP-PEAP, EAP-TLS, and EAP-TTLS.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>

src/eap_common/eap_gpsk_common.c

@@ -340,6 +340,141 @@ int eap_gpsk_derive_keys(const u8 *psk, size_t psk_len, int vendor,
 }
 
 
+static int eap_gpsk_derive_mid_helper(u32 csuite_specifier,
+				      u8 *kdf_out, size_t kdf_out_len,
+				      const u8 *psk, const u8 *seed,
+				      size_t seed_len, u8 method_type)
+{
+	u8 *pos, *data;
+	size_t data_len;
+	int (*gkdf)(const u8 *_psk, const u8 *_data, size_t _data_len,
+		    u8 *buf, size_t len);
+
+	gkdf = NULL;
+	switch (csuite_specifier) {
+	case EAP_GPSK_CIPHER_AES:
+		gkdf = eap_gpsk_gkdf_cmac;
+		break;
+#ifdef EAP_GPSK_SHA256
+	case EAP_GPSK_CIPHER_SHA256:
+		gkdf = eap_gpsk_gkdf_sha256;
+		break;
+#endif /* EAP_GPSK_SHA256 */
+	default:
+		wpa_printf(MSG_DEBUG, "EAP-GPSK: Unknown cipher %d used in "
+			   "Session-Id derivation", csuite_specifier);
+		return -1;
+	}
+
+#define SID_LABEL "Method ID"
+	/* "Method ID" || EAP_Method_Type || CSuite_Sel || inputString */
+	data_len = strlen(SID_LABEL) + 1 + 6 + seed_len;
+	data = os_malloc(data_len);
+	if (data == NULL)
+		return -1;
+	pos = data;
+	os_memcpy(pos, SID_LABEL, strlen(SID_LABEL));
+	pos += strlen(SID_LABEL);
+#undef SID_LABEL
+	os_memcpy(pos, &method_type, 1);
+	pos += 1;
+	WPA_PUT_BE32(pos, EAP_GPSK_VENDOR_IETF); /* CSuite/Vendor = IETF */
+	pos += 4;
+	WPA_PUT_BE16(pos, csuite_specifier); /* CSuite/Specifier */
+	pos += 2;
+	os_memcpy(pos, seed, seed_len); /* inputString */
+	wpa_hexdump(MSG_DEBUG, "EAP-GPSK: Data to Method ID derivation",
+		    data, data_len);
+
+	if (gkdf(psk, data, data_len, kdf_out, kdf_out_len) < 0) {
+		os_free(data);
+		return -1;
+	}
+	os_free(data);
+	wpa_hexdump(MSG_DEBUG, "EAP-GPSK: Method ID", kdf_out, kdf_out_len);
+
+	return 0;
+}
+
+
+/**
+ * eap_gpsk_session_id - Derive EAP-GPSK Session ID
+ * @psk: Pre-shared key
+ * @psk_len: Length of psk in bytes
+ * @vendor: CSuite/Vendor
+ * @specifier: CSuite/Specifier
+ * @rand_peer: 32-byte RAND_Peer
+ * @rand_server: 32-byte RAND_Server
+ * @id_peer: ID_Peer
+ * @id_peer_len: Length of ID_Peer
+ * @id_server: ID_Server
+ * @id_server_len: Length of ID_Server
+ * @method_type: EAP Authentication Method Type
+ * @sid: Buffer for 17-byte Session ID
+ * @sid_len: Buffer for returning length of Session ID
+ * Returns: 0 on success, -1 on failure
+ */
+int eap_gpsk_derive_session_id(const u8 *psk, size_t psk_len, int vendor,
+			       int specifier,
+			       const u8 *rand_peer, const u8 *rand_server,
+			       const u8 *id_peer, size_t id_peer_len,
+			       const u8 *id_server, size_t id_server_len,
+			       u8 method_type, u8 *sid, size_t *sid_len)
+{
+	u8 *seed, *pos;
+	u8 kdf_out[16];
+	size_t seed_len;
+	int ret;
+
+	wpa_printf(MSG_DEBUG, "EAP-GPSK: Deriving Session ID(%d:%d)",
+		   vendor, specifier);
+
+	if (vendor != EAP_GPSK_VENDOR_IETF)
+		return -1;
+
+	wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: PSK", psk, psk_len);
+
+	/*
+	 * inputString = RAND_Peer || ID_Peer || RAND_Server || ID_Server
+	 *            (= seed)
+	 * KS = 16, CSuite_Sel = 0x00000000 0x0001
+	 * Method-ID = GKDF-16 (zero, "Method ID" || EAP_Method_Type ||
+	 *                      CSuite_Sel || inputString)
+	 */
+	seed_len = 2 * EAP_GPSK_RAND_LEN + id_server_len + id_peer_len;
+	seed = os_malloc(seed_len);
+	if (seed == NULL) {
+		wpa_printf(MSG_DEBUG, "EAP-GPSK: Failed to allocate memory "
+			   "for Session-Id derivation");
+		return -1;
+	}
+
+	pos = seed;
+	os_memcpy(pos, rand_peer, EAP_GPSK_RAND_LEN);
+	pos += EAP_GPSK_RAND_LEN;
+	os_memcpy(pos, id_peer, id_peer_len);
+	pos += id_peer_len;
+	os_memcpy(pos, rand_server, EAP_GPSK_RAND_LEN);
+	pos += EAP_GPSK_RAND_LEN;
+	os_memcpy(pos, id_server, id_server_len);
+	pos += id_server_len;
+	wpa_hexdump(MSG_DEBUG, "EAP-GPSK: Seed", seed, seed_len);
+
+	ret = eap_gpsk_derive_mid_helper(specifier,
+					 kdf_out, sizeof(kdf_out),
+					 psk, seed, seed_len,
+					 method_type);
+
+	sid[0] = method_type;
+	os_memcpy(sid + 1, kdf_out, sizeof(kdf_out));
+	*sid_len = 1 + sizeof(kdf_out);
+
+	os_free(seed);
+
+	return ret;
+}
+
+
 /**
  * eap_gpsk_mic_len - Get the length of the MIC
  * @vendor: CSuite/Vendor

src/eap_common/eap_gpsk_common.h

@@ -53,6 +53,12 @@ int eap_gpsk_derive_keys(const u8 *psk, size_t psk_len, int vendor,
 			 const u8 *id_server, size_t id_server_len,
 			 u8 *msk, u8 *emsk, u8 *sk, size_t *sk_len,
 			 u8 *pk, size_t *pk_len);
+int eap_gpsk_derive_session_id(const u8 *psk, size_t psk_len, int vendor,
+			       int specifier,
+			       const u8 *rand_peer, const u8 *rand_server,
+			       const u8 *id_peer, size_t id_peer_len,
+			       const u8 *id_server, size_t id_server_len,
+			       u8 method_type, u8 *sid, size_t *sid_len);
 size_t eap_gpsk_mic_len(int vendor, int specifier);
 int eap_gpsk_compute_mic(const u8 *sk, size_t sk_len, int vendor,
 			 int specifier, const u8 *data, size_t len, u8 *mic);

src/eap_peer/eap.c

@@ -161,6 +161,8 @@ SM_STATE(EAP, INITIALIZE)
 	eapol_set_bool(sm, EAPOL_eapFail, FALSE);
 	os_free(sm->eapKeyData);
 	sm->eapKeyData = NULL;
+	os_free(sm->eapSessionId);
+	sm->eapSessionId = NULL;
 	sm->eapKeyAvailable = FALSE;
 	eapol_set_bool(sm, EAPOL_eapRestart, FALSE);
 	sm->lastId = -1; /* new session - make sure this does not match with
@@ -403,6 +405,13 @@ SM_STATE(EAP, METHOD)
 		os_free(sm->eapKeyData);
 		sm->eapKeyData = sm->m->getKey(sm, sm->eap_method_priv,
 					       &sm->eapKeyDataLen);
+		os_free(sm->eapSessionId);
+		sm->eapSessionId = sm->m->getSessionId(sm, sm->eap_method_priv,
+						       &sm->eapSessionIdLen);
+		if (sm->eapSessionId) {
+			wpa_hexdump(MSG_DEBUG, "EAP: Session-Id",
+				    sm->eapSessionId, sm->eapSessionIdLen);
+		}
 	}
 }
 
@@ -1462,6 +1471,8 @@ void eap_sm_abort(struct eap_sm *sm)
 	sm->eapRespData = NULL;
 	os_free(sm->eapKeyData);
 	sm->eapKeyData = NULL;
+	os_free(sm->eapSessionId);
+	sm->eapSessionId = NULL;
 
 	/* This is not clearly specified in the EAP statemachines draft, but
 	 * it seems necessary to make sure that some of the EAPOL variables get
@@ -2158,6 +2169,28 @@ void eap_notify_lower_layer_success(struct eap_sm *sm)
 }
 
 
+/**
+ * eap_get_eapSessionId - Get Session-Id from EAP state machine
+ * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
+ * @len: Pointer to variable that will be set to number of bytes in the session
+ * Returns: Pointer to the EAP Session-Id or %NULL on failure
+ *
+ * Fetch EAP Session-Id from the EAP state machine. The Session-Id is available
+ * only after a successful authentication. EAP state machine continues to manage
+ * the Session-Id and the caller must not change or free the returned data.
+ */
+const u8 * eap_get_eapSessionId(struct eap_sm *sm, size_t *len)
+{
+	if (sm == NULL || sm->eapSessionId == NULL) {
+		*len = 0;
+		return NULL;
+	}
+
+	*len = sm->eapSessionIdLen;
+	return sm->eapSessionId;
+}
+
+
 /**
  * eap_get_eapKeyData - Get master session key (MSK) from EAP state machine
  * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()

src/eap_peer/eap.h

@@ -306,6 +306,7 @@ void eap_set_force_disabled(struct eap_sm *sm, int disabled);
 int eap_key_available(struct eap_sm *sm);
 void eap_notify_success(struct eap_sm *sm);
 void eap_notify_lower_layer_success(struct eap_sm *sm);
+const u8 * eap_get_eapSessionId(struct eap_sm *sm, size_t *len);
 const u8 * eap_get_eapKeyData(struct eap_sm *sm, size_t *len);
 struct wpabuf * eap_get_eapRespData(struct eap_sm *sm);
 void eap_register_scard_ctx(struct eap_sm *sm, void *ctx);

src/eap_peer/eap_fast.c

@@ -53,6 +53,8 @@ struct eap_fast_data {
 	int session_ticket_used;
 
 	u8 key_data[EAP_FAST_KEY_LEN];
+	u8 *session_id;
+	size_t id_len;
 	u8 emsk[EAP_EMSK_LEN];
 	int success;
 
@@ -238,6 +240,7 @@ static void eap_fast_deinit(struct eap_sm *sm, void *priv)
 		pac = pac->next;
 		eap_fast_free_pac(prev);
 	}
+	os_free(data->session_id);
 	wpabuf_free(data->pending_phase2_req);
 	os_free(data);
 }
@@ -785,6 +788,21 @@ static struct wpabuf * eap_fast_process_crypto_binding(
 		return NULL;
 	}
 
+	if (!data->anon_provisioning && data->phase2_success) {
+		os_free(data->session_id);
+		data->session_id = eap_peer_tls_derive_session_id(
+			sm, &data->ssl, EAP_TYPE_FAST, &data->id_len);
+		if (data->session_id) {
+			wpa_hexdump(MSG_DEBUG, "EAP-FAST: Derived Session-Id",
+				    data->session_id, data->id_len);
+		} else {
+			wpa_printf(MSG_ERROR, "EAP-FAST: Failed to derive "
+				   "Session-Id");
+			wpabuf_free(resp);
+			return NULL;
+		}
+	}
+
 	pos = wpabuf_put(resp, sizeof(struct eap_tlv_crypto_binding_tlv));
 	eap_fast_write_crypto_binding((struct eap_tlv_crypto_binding_tlv *)
 				      pos, _bind, cmk);
@@ -1604,6 +1622,8 @@ static void * eap_fast_init_for_reauth(struct eap_sm *sm, void *priv)
 		os_free(data);
 		return NULL;
 	}
+	os_free(data->session_id);
+	data->session_id = NULL;
 	if (data->phase2_priv && data->phase2_method &&
 	    data->phase2_method->init_for_reauth)
 		data->phase2_method->init_for_reauth(sm, data->phase2_priv);
@@ -1662,6 +1682,25 @@ static u8 * eap_fast_getKey(struct eap_sm *sm, void *priv, size_t *len)
 }
 
 
+static u8 * eap_fast_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
+{
+	struct eap_fast_data *data = priv;
+	u8 *id;
+
+	if (!data->success)
+		return NULL;
+
+	id = os_malloc(data->id_len);
+	if (id == NULL)
+		return NULL;
+
+	*len = data->id_len;
+	os_memcpy(id, data->session_id, data->id_len);
+
+	return id;
+}
+
+
 static u8 * eap_fast_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 {
 	struct eap_fast_data *data = priv;
@@ -1696,6 +1735,7 @@ int eap_peer_fast_register(void)
 	eap->process = eap_fast_process;
 	eap->isKeyAvailable = eap_fast_isKeyAvailable;
 	eap->getKey = eap_fast_getKey;
+	eap->getSessionId = eap_fast_get_session_id;
 	eap->get_status = eap_fast_get_status;
 #if 0
 	eap->has_reauth_data = eap_fast_has_reauth_data;

src/eap_peer/eap_gpsk.c

@@ -23,8 +23,8 @@ struct eap_gpsk_data {
 	size_t sk_len;
 	u8 pk[EAP_GPSK_MAX_PK_LEN];
 	size_t pk_len;
-	u8 session_id;
+	u8 session_id[128];
-	int session_id_set;
+	size_t id_len;
 	u8 *id_peer;
 	size_t id_peer_len;
 	u8 *id_server;
@@ -354,6 +354,21 @@ static struct wpabuf * eap_gpsk_send_gpsk_2(struct eap_gpsk_data *data,
 		return NULL;
 	}
 
+	if (eap_gpsk_derive_session_id(data->psk, data->psk_len,
+				       data->vendor, data->specifier,
+				       data->rand_peer, data->rand_server,
+				       data->id_peer, data->id_peer_len,
+				       data->id_server, data->id_server_len,
+				       EAP_TYPE_GPSK,
+				       data->session_id, &data->id_len) < 0) {
+		wpa_printf(MSG_DEBUG, "EAP-GPSK: Failed to derive Session-Id");
+		eap_gpsk_state(data, FAILURE);
+		wpabuf_free(resp);
+		return NULL;
+	}
+	wpa_hexdump(MSG_DEBUG, "EAP-GPSK: Derived Session-Id",
+		    data->session_id, data->id_len);
+
 	/* No PD_Payload_1 */
 	wpabuf_put_be16(resp, 0);
 
@@ -708,6 +723,24 @@ static u8 * eap_gpsk_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 }
 
 
+static u8 * eap_gpsk_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
+{
+	struct eap_gpsk_data *data = priv;
+	u8 *sid;
+
+	if (data->state != SUCCESS)
+		return NULL;
+
+	sid = os_malloc(data->id_len);
+	if (sid == NULL)
+		return NULL;
+	os_memcpy(sid, data->session_id, data->id_len);
+	*len = data->id_len;
+
+	return sid;
+}
+
+
 int eap_peer_gpsk_register(void)
 {
 	struct eap_method *eap;
@@ -724,6 +757,7 @@ int eap_peer_gpsk_register(void)
 	eap->isKeyAvailable = eap_gpsk_isKeyAvailable;
 	eap->getKey = eap_gpsk_getKey;
 	eap->get_emsk = eap_gpsk_get_emsk;
+	eap->getSessionId = eap_gpsk_get_session_id;
 
 	ret = eap_peer_method_register(eap);
 	if (ret)

src/eap_peer/eap_i.h

@@ -261,6 +261,19 @@ struct eap_method {
 	 * private data or this function may derive the key.
 	 */
 	u8 * (*get_emsk)(struct eap_sm *sm, void *priv, size_t *len);
+
+	/**
+	 * getSessionId - Get EAP method specific Session-Id
+	 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
+	 * @priv: Pointer to private EAP method data from eap_method::init()
+	 * @len: Pointer to a variable to store Session-Id length
+	 * Returns: Session-Id or %NULL if not available
+	 *
+	 * This function can be used to get the Session-Id from the EAP method.
+	 * The Session-Id may already be stored in the method-specific private
+	 * data or this function may derive the Session-Id.
+	 */
+	u8 * (*getSessionId)(struct eap_sm *sm, void *priv, size_t *len);
 };
 
 
@@ -298,6 +311,8 @@ struct eap_sm {
 	Boolean eapKeyAvailable; /* peer to lower layer */
 	u8 *eapKeyData; /* peer to lower layer */
 	size_t eapKeyDataLen; /* peer to lower layer */
+	u8 *eapSessionId; /* peer to lower layer */
+	size_t eapSessionIdLen; /* peer to lower layer */
 	const struct eap_method *m; /* selected EAP method */
 	/* not defined in RFC 4137 */
 	Boolean changed;

src/eap_peer/eap_ikev2.c

@@ -475,6 +475,36 @@ static u8 * eap_ikev2_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 }
 
 
+static u8 * eap_ikev2_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
+{
+	struct eap_ikev2_data *data = priv;
+	u8 *sid;
+	size_t sid_len;
+	size_t offset;
+
+	if (data->state != DONE || !data->keymat_ok)
+		return NULL;
+
+	sid_len = 1 + data->ikev2.i_nonce_len + data->ikev2.r_nonce_len;
+	sid = os_malloc(sid_len);
+	if (sid) {
+		offset = 0;
+		sid[offset] = EAP_TYPE_IKEV2;
+		offset++;
+		os_memcpy(sid + offset, data->ikev2.i_nonce,
+			  data->ikev2.i_nonce_len);
+		offset += data->ikev2.i_nonce_len;
+		os_memcpy(sid + offset, data->ikev2.r_nonce,
+			  data->ikev2.r_nonce_len);
+		*len = sid_len;
+		wpa_hexdump(MSG_DEBUG, "EAP-IKEV2: Derived Session-Id",
+			    sid, sid_len);
+	}
+
+	return sid;
+}
+
+
 int eap_peer_ikev2_register(void)
 {
 	struct eap_method *eap;
@@ -492,6 +522,7 @@ int eap_peer_ikev2_register(void)
 	eap->isKeyAvailable = eap_ikev2_isKeyAvailable;
 	eap->getKey = eap_ikev2_getKey;
 	eap->get_emsk = eap_ikev2_get_emsk;
+	eap->getSessionId = eap_ikev2_get_session_id;
 
 	ret = eap_peer_method_register(eap);
 	if (ret)

src/eap_peer/eap_peap.c

@@ -56,6 +56,8 @@ struct eap_peap_data {
 	int resuming; /* starting a resumed session */
 	int reauth; /* reauthentication */
 	u8 *key_data;
+	u8 *session_id;
+	size_t id_len;
 
 	struct wpabuf *pending_phase2_req;
 	enum { NO_BINDING, OPTIONAL_BINDING, REQUIRE_BINDING } crypto_binding;
@@ -179,6 +181,7 @@ static void eap_peap_deinit(struct eap_sm *sm, void *priv)
 	os_free(data->phase2_types);
 	eap_peer_tls_ssl_deinit(sm, &data->ssl);
 	os_free(data->key_data);
+	os_free(data->session_id);
 	wpabuf_free(data->pending_phase2_req);
 	os_free(data);
 }
@@ -1107,6 +1110,20 @@ static struct wpabuf * eap_peap_process(struct eap_sm *sm, void *priv,
 					   "derive key");
 			}
 
+			os_free(data->session_id);
+			data->session_id =
+				eap_peer_tls_derive_session_id(sm, &data->ssl,
+							       EAP_TYPE_PEAP,
+							       &data->id_len);
+			if (data->session_id) {
+				wpa_hexdump(MSG_DEBUG,
+					    "EAP-PEAP: Derived Session-Id",
+					    data->session_id, data->id_len);
+			} else {
+				wpa_printf(MSG_ERROR, "EAP-PEAP: Failed to "
+					   "derive Session-Id");
+			}
+
 			if (sm->workaround && data->resuming) {
 				/*
 				 * At least few RADIUS servers (Aegis v1.1.6;
@@ -1178,6 +1195,8 @@ static void * eap_peap_init_for_reauth(struct eap_sm *sm, void *priv)
 	struct eap_peap_data *data = priv;
 	os_free(data->key_data);
 	data->key_data = NULL;
+	os_free(data->session_id);
+	data->session_id = NULL;
 	if (eap_peer_tls_reauth_init(sm, &data->ssl)) {
 		os_free(data);
 		return NULL;
@@ -1260,6 +1279,25 @@ static u8 * eap_peap_getKey(struct eap_sm *sm, void *priv, size_t *len)
 }
 
 
+static u8 * eap_peap_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
+{
+	struct eap_peap_data *data = priv;
+	u8 *id;
+
+	if (data->session_id == NULL || !data->phase2_success)
+		return NULL;
+
+	id = os_malloc(data->id_len);
+	if (id == NULL)
+		return NULL;
+
+	*len = data->id_len;
+	os_memcpy(id, data->session_id, data->id_len);
+
+	return id;
+}
+
+
 int eap_peer_peap_register(void)
 {
 	struct eap_method *eap;
@@ -1279,6 +1317,7 @@ int eap_peer_peap_register(void)
 	eap->has_reauth_data = eap_peap_has_reauth_data;
 	eap->deinit_for_reauth = eap_peap_deinit_for_reauth;
 	eap->init_for_reauth = eap_peap_init_for_reauth;
+	eap->getSessionId = eap_peap_get_session_id;
 
 	ret = eap_peer_method_register(eap);
 	if (ret)

src/eap_peer/eap_tls.c

@@ -21,6 +21,8 @@ static void eap_tls_deinit(struct eap_sm *sm, void *priv);
 struct eap_tls_data {
 	struct eap_ssl_data ssl;
 	u8 *key_data;
+	u8 *session_id;
+	size_t id_len;
 	void *ssl_ctx;
 	u8 eap_type;
 };
@@ -103,6 +105,7 @@ static void eap_tls_deinit(struct eap_sm *sm, void *priv)
 		return;
 	eap_peer_tls_ssl_deinit(sm, &data->ssl);
 	os_free(data->key_data);
+	os_free(data->session_id);
 	os_free(data);
 }
 
@@ -165,6 +168,17 @@ static void eap_tls_success(struct eap_sm *sm, struct eap_tls_data *data,
 	} else {
 		wpa_printf(MSG_INFO, "EAP-TLS: Failed to derive key");
 	}
+
+	os_free(data->session_id);
+	data->session_id = eap_peer_tls_derive_session_id(sm, &data->ssl,
+							  EAP_TYPE_TLS,
+			                                  &data->id_len);
+	if (data->session_id) {
+		wpa_hexdump(MSG_DEBUG, "EAP-TLS: Derived Session-Id",
+			    data->session_id, data->id_len);
+	} else {
+		wpa_printf(MSG_ERROR, "EAP-TLS: Failed to derive Session-Id");
+	}
 }
 
 
@@ -228,6 +242,8 @@ static void * eap_tls_init_for_reauth(struct eap_sm *sm, void *priv)
 	struct eap_tls_data *data = priv;
 	os_free(data->key_data);
 	data->key_data = NULL;
+	os_free(data->session_id);
+	data->session_id = NULL;
 	if (eap_peer_tls_reauth_init(sm, &data->ssl)) {
 		os_free(data);
 		return NULL;
@@ -289,6 +305,25 @@ static u8 * eap_tls_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 }
 
 
+static u8 * eap_tls_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
+{
+	struct eap_tls_data *data = priv;
+	u8 *id;
+
+	if (data->session_id == NULL)
+		return NULL;
+
+	id = os_malloc(data->id_len);
+	if (id == NULL)
+		return NULL;
+
+	*len = data->id_len;
+	os_memcpy(id, data->session_id, data->id_len);
+
+	return id;
+}
+
+
 int eap_peer_tls_register(void)
 {
 	struct eap_method *eap;
@@ -304,6 +339,7 @@ int eap_peer_tls_register(void)
 	eap->process = eap_tls_process;
 	eap->isKeyAvailable = eap_tls_isKeyAvailable;
 	eap->getKey = eap_tls_getKey;
+	eap->getSessionId = eap_tls_get_session_id;
 	eap->get_status = eap_tls_get_status;
 	eap->has_reauth_data = eap_tls_has_reauth_data;
 	eap->deinit_for_reauth = eap_tls_deinit_for_reauth;

src/eap_peer/eap_tls_common.c

@@ -339,6 +339,52 @@ fail:
 }
 
 
+/**
+ * eap_peer_tls_derive_session_id - Derive a Session-Id based on TLS data
+ * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init()
+ * @data: Data for TLS processing
+ * @eap_type: EAP method used in Phase 1 (EAP_TYPE_TLS/PEAP/TTLS/FAST)
+ * @len: Pointer to length of the session ID generated
+ * Returns: Pointer to allocated Session-Id on success or %NULL on failure
+ *
+ * This function derive the Session-Id based on the TLS session data
+ * (client/server random and method type).
+ *
+ * The caller is responsible for freeing the returned buffer.
+ */
+u8 * eap_peer_tls_derive_session_id(struct eap_sm *sm,
+				    struct eap_ssl_data *data, u8 eap_type,
+				    size_t *len)
+{
+	struct tls_keys keys;
+	u8 *out;
+
+	/*
+	 * TLS library did not support session ID generation,
+	 * so get the needed TLS session parameters
+	 */
+	if (tls_connection_get_keys(sm->ssl_ctx, data->conn, &keys))
+		return NULL;
+
+	if (keys.client_random == NULL || keys.server_random == NULL ||
+	    keys.master_key == NULL)
+		return NULL;
+
+	*len = 1 + keys.client_random_len + keys.server_random_len;
+	out = os_malloc(*len);
+	if (out == NULL)
+		return NULL;
+
+	/* Session-Id = EAP type || client.random || server.random */
+	out[0] = eap_type;
+	os_memcpy(out + 1, keys.client_random, keys.client_random_len);
+	os_memcpy(out + 1 + keys.client_random_len, keys.server_random,
+	          keys.server_random_len);
+
+	return out;
+}
+
+
 /**
  * eap_peer_tls_reassemble_fragment - Reassemble a received fragment
  * @data: Data for TLS processing

src/eap_peer/eap_tls_common.h

@@ -94,6 +94,9 @@ int eap_peer_tls_ssl_init(struct eap_sm *sm, struct eap_ssl_data *data,
 void eap_peer_tls_ssl_deinit(struct eap_sm *sm, struct eap_ssl_data *data);
 u8 * eap_peer_tls_derive_key(struct eap_sm *sm, struct eap_ssl_data *data,
 			     const char *label, size_t len);
+u8 * eap_peer_tls_derive_session_id(struct eap_sm *sm,
+				    struct eap_ssl_data *data, u8 eap_type,
+				    size_t *len);
 int eap_peer_tls_process_helper(struct eap_sm *sm, struct eap_ssl_data *data,
 				EapType eap_type, int peap_version,
 				u8 id, const u8 *in_data, size_t in_len,

src/eap_peer/eap_ttls.c

@@ -54,6 +54,8 @@ struct eap_ttls_data {
 	int resuming; /* starting a resumed session */
 	int reauth; /* reauthentication */
 	u8 *key_data;
+	u8 *session_id;
+	size_t id_len;
 
 	struct wpabuf *pending_phase2_req;
 
@@ -140,6 +142,7 @@ static void eap_ttls_deinit(struct eap_sm *sm, void *priv)
 	os_free(data->phase2_eap_types);
 	eap_peer_tls_ssl_deinit(sm, &data->ssl);
 	os_free(data->key_data);
+	os_free(data->session_id);
 	wpabuf_free(data->pending_phase2_req);
 	os_free(data);
 }
@@ -222,6 +225,17 @@ static int eap_ttls_v0_derive_key(struct eap_sm *sm,
 	wpa_hexdump_key(MSG_DEBUG, "EAP-TTLS: Derived key",
 			data->key_data, EAP_TLS_KEY_LEN);
 
+	os_free(data->session_id);
+	data->session_id = eap_peer_tls_derive_session_id(sm, &data->ssl,
+							  EAP_TYPE_TTLS,
+	                                                  &data->id_len);
+	if (data->session_id) {
+		wpa_hexdump(MSG_DEBUG, "EAP-TTLS: Derived Session-Id",
+			    data->session_id, data->id_len);
+	} else {
+		wpa_printf(MSG_ERROR, "EAP-TTLS: Failed to derive Session-Id");
+	}
+
 	return 0;
 }
 
@@ -1528,6 +1542,8 @@ static void * eap_ttls_init_for_reauth(struct eap_sm *sm, void *priv)
 	struct eap_ttls_data *data = priv;
 	os_free(data->key_data);
 	data->key_data = NULL;
+	os_free(data->session_id);
+	data->session_id = NULL;
 	if (eap_peer_tls_reauth_init(sm, &data->ssl)) {
 		os_free(data);
 		return NULL;
@@ -1612,6 +1628,25 @@ static u8 * eap_ttls_getKey(struct eap_sm *sm, void *priv, size_t *len)
 }
 
 
+static u8 * eap_ttls_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
+{
+	struct eap_ttls_data *data = priv;
+	u8 *id;
+
+	if (data->session_id == NULL || !data->phase2_success)
+		return NULL;
+
+	id = os_malloc(data->id_len);
+	if (id == NULL)
+		return NULL;
+
+	*len = data->id_len;
+	os_memcpy(id, data->session_id, data->id_len);
+
+	return id;
+}
+
+
 int eap_peer_ttls_register(void)
 {
 	struct eap_method *eap;
@@ -1627,6 +1662,7 @@ int eap_peer_ttls_register(void)
 	eap->process = eap_ttls_process;
 	eap->isKeyAvailable = eap_ttls_isKeyAvailable;
 	eap->getKey = eap_ttls_getKey;
+	eap->getSessionId = eap_ttls_get_session_id;
 	eap->get_status = eap_ttls_get_status;
 	eap->has_reauth_data = eap_ttls_has_reauth_data;
 	eap->deinit_for_reauth = eap_ttls_deinit_for_reauth;