eap_sim.c

IEEE 802.11a/b/g 服务器端AP

			   "did not include%s%s",
			   !attr->mac ? " AT_MAC" : "",
			   !attr->rand ? " AT_RAND" : "");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}

	wpa_printf(MSG_DEBUG, "EAP-SIM: %lu challenges",
		   (unsigned long) attr->num_chal);
	if (attr->num_chal < data->min_num_chal) {
		wpa_printf(MSG_INFO, "EAP-SIM: Insufficient number of "
			   "challenges (%lu)", (unsigned long) attr->num_chal);
		return eap_sim_client_error(data, id,
					    EAP_SIM_INSUFFICIENT_NUM_OF_CHAL);
	}
	if (attr->num_chal > 3) {
		wpa_printf(MSG_INFO, "EAP-SIM: Too many challenges "
			   "(%lu)", (unsigned long) attr->num_chal);
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}

	/* Verify that RANDs are different */
	if (os_memcmp(attr->rand, attr->rand + GSM_RAND_LEN,
		   GSM_RAND_LEN) == 0 ||
	    (attr->num_chal > 2 &&
	     (os_memcmp(attr->rand, attr->rand + 2 * GSM_RAND_LEN,
			GSM_RAND_LEN) == 0 ||
	      os_memcmp(attr->rand + GSM_RAND_LEN,
			attr->rand + 2 * GSM_RAND_LEN,
			GSM_RAND_LEN) == 0))) {
		wpa_printf(MSG_INFO, "EAP-SIM: Same RAND used multiple times");
		return eap_sim_client_error(data, id,
					    EAP_SIM_RAND_NOT_FRESH);
	}

	os_memcpy(data->rand, attr->rand, attr->num_chal * GSM_RAND_LEN);
	data->num_chal = attr->num_chal;
		
	if (eap_sim_gsm_auth(sm, data)) {
		wpa_printf(MSG_WARNING, "EAP-SIM: GSM authentication failed");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}
	if (data->last_eap_identity) {
		identity = data->last_eap_identity;
		identity_len = data->last_eap_identity_len;
	} else if (data->pseudonym) {
		identity = data->pseudonym;
		identity_len = data->pseudonym_len;
	} else
		identity = eap_get_config_identity(sm, &identity_len);
	wpa_hexdump_ascii(MSG_DEBUG, "EAP-SIM: Selected identity for MK "
			  "derivation", identity, identity_len);
	eap_sim_derive_mk(identity, identity_len, data->nonce_mt,
			  data->selected_version, data->ver_list,
			  data->ver_list_len, data->num_chal,
			  (const u8 *) data->kc, data->mk);
	eap_sim_derive_keys(data->mk, data->k_encr, data->k_aut, data->msk,
			    data->emsk);
	if (eap_sim_verify_mac(data->k_aut, reqData, attr->mac, data->nonce_mt,
			       EAP_SIM_NONCE_MT_LEN)) {
		wpa_printf(MSG_WARNING, "EAP-SIM: Challenge message "
			   "used invalid AT_MAC");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}

	/* Old reauthentication and pseudonym identities must not be used
	 * anymore. In other words, if no new identities are received, full
	 * authentication will be used on next reauthentication. */
	eap_sim_clear_identities(data, CLEAR_PSEUDONYM | CLEAR_REAUTH_ID |
				 CLEAR_EAP_ID);

	if (attr->encr_data) {
		u8 *decrypted;
		decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
					       attr->encr_data_len, attr->iv,
					       &eattr, 0);
		if (decrypted == NULL) {
			return eap_sim_client_error(
				data, id, EAP_SIM_UNABLE_TO_PROCESS_PACKET);
		}
		eap_sim_learn_ids(data, &eattr);
		os_free(decrypted);
	}

	if (data->result_ind && attr->result_ind)
		data->use_result_ind = 1;

	if (data->state != FAILURE && data->state != RESULT_FAILURE) {
		eap_sim_state(data, data->use_result_ind ?
			      RESULT_SUCCESS : SUCCESS);
	}

	data->num_id_req = 0;
	data->num_notification = 0;
	/* RFC 4186 specifies that counter is initialized to one after
	 * fullauth, but initializing it to zero makes it easier to implement
	 * reauth verification. */
	data->counter = 0;
	return eap_sim_response_challenge(data, id);
}


static int eap_sim_process_notification_reauth(struct eap_sim_data *data,
					       struct eap_sim_attrs *attr)
{
	struct eap_sim_attrs eattr;
	u8 *decrypted;

	if (attr->encr_data == NULL || attr->iv == NULL) {
		wpa_printf(MSG_WARNING, "EAP-SIM: Notification message after "
			   "reauth did not include encrypted data");
		return -1;
	}

	decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
				       attr->encr_data_len, attr->iv, &eattr,
				       0);
	if (decrypted == NULL) {
		wpa_printf(MSG_WARNING, "EAP-SIM: Failed to parse encrypted "
			   "data from notification message");
		return -1;
	}

	if (eattr.counter < 0 || (size_t) eattr.counter != data->counter) {
		wpa_printf(MSG_WARNING, "EAP-SIM: Counter in notification "
			   "message does not match with counter in reauth "
			   "message");
		os_free(decrypted);
		return -1;
	}

	os_free(decrypted);
	return 0;
}


static int eap_sim_process_notification_auth(struct eap_sim_data *data,
					     const struct wpabuf *reqData,
					     struct eap_sim_attrs *attr)
{
	if (attr->mac == NULL) {
		wpa_printf(MSG_INFO, "EAP-SIM: no AT_MAC in after_auth "
			   "Notification message");
		return -1;
	}

	if (eap_sim_verify_mac(data->k_aut, reqData, attr->mac, (u8 *) "", 0))
	{
		wpa_printf(MSG_WARNING, "EAP-SIM: Notification message "
			   "used invalid AT_MAC");
		return -1;
	}

	if (data->reauth &&
	    eap_sim_process_notification_reauth(data, attr)) {
		wpa_printf(MSG_WARNING, "EAP-SIM: Invalid notification "
			   "message after reauth");
		return -1;
	}

	return 0;
}


static struct wpabuf * eap_sim_process_notification(
	struct eap_sm *sm, struct eap_sim_data *data, u8 id,
	const struct wpabuf *reqData, struct eap_sim_attrs *attr)
{
	wpa_printf(MSG_DEBUG, "EAP-SIM: subtype Notification");
	if (data->num_notification > 0) {
		wpa_printf(MSG_INFO, "EAP-SIM: too many notification "
			   "rounds (only one allowed)");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}
	data->num_notification++;
	if (attr->notification == -1) {
		wpa_printf(MSG_INFO, "EAP-SIM: no AT_NOTIFICATION in "
			   "Notification message");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}

	if ((attr->notification & 0x4000) == 0 &&
	    eap_sim_process_notification_auth(data, reqData, attr)) {
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}

	eap_sim_report_notification(sm->msg_ctx, attr->notification, 0);
	if (attr->notification >= 0 && attr->notification < 32768) {
		eap_sim_state(data, FAILURE);
	} else if (attr->notification == EAP_SIM_SUCCESS &&
		   data->state == RESULT_SUCCESS)
		eap_sim_state(data, SUCCESS);
	return eap_sim_response_notification(data, id, attr->notification);
}


static struct wpabuf * eap_sim_process_reauthentication(
	struct eap_sm *sm, struct eap_sim_data *data, u8 id,
	const struct wpabuf *reqData, struct eap_sim_attrs *attr)
{
	struct eap_sim_attrs eattr;
	u8 *decrypted;

	wpa_printf(MSG_DEBUG, "EAP-SIM: subtype Reauthentication");

	if (data->reauth_id == NULL) {
		wpa_printf(MSG_WARNING, "EAP-SIM: Server is trying "
			   "reauthentication, but no reauth_id available");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}

	data->reauth = 1;
	if (eap_sim_verify_mac(data->k_aut, reqData, attr->mac, (u8 *) "", 0))
	{
		wpa_printf(MSG_WARNING, "EAP-SIM: Reauthentication "
			   "did not have valid AT_MAC");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}

	if (attr->encr_data == NULL || attr->iv == NULL) {
		wpa_printf(MSG_WARNING, "EAP-SIM: Reauthentication "
			   "message did not include encrypted data");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}

	decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
				       attr->encr_data_len, attr->iv, &eattr,
				       0);
	if (decrypted == NULL) {
		wpa_printf(MSG_WARNING, "EAP-SIM: Failed to parse encrypted "
			   "data from reauthentication message");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}

	if (eattr.nonce_s == NULL || eattr.counter < 0) {
		wpa_printf(MSG_INFO, "EAP-SIM: (encr) No%s%s in reauth packet",
			   !eattr.nonce_s ? " AT_NONCE_S" : "",
			   eattr.counter < 0 ? " AT_COUNTER" : "");
		os_free(decrypted);
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}

	if (eattr.counter < 0 || (size_t) eattr.counter <= data->counter) {
		wpa_printf(MSG_INFO, "EAP-SIM: (encr) Invalid counter "
			   "(%d <= %d)", eattr.counter, data->counter);
		data->counter_too_small = eattr.counter;
		/* Reply using Re-auth w/ AT_COUNTER_TOO_SMALL. The current
		 * reauth_id must not be used to start a new reauthentication.
		 * However, since it was used in the last EAP-Response-Identity
		 * packet, it has to saved for the following fullauth to be
		 * used in MK derivation. */
		os_free(data->last_eap_identity);
		data->last_eap_identity = data->reauth_id;
		data->last_eap_identity_len = data->reauth_id_len;
		data->reauth_id = NULL;
		data->reauth_id_len = 0;
		os_free(decrypted);
		return eap_sim_response_reauth(data, id, 1);
	}
	data->counter = eattr.counter;

	os_memcpy(data->nonce_s, eattr.nonce_s, EAP_SIM_NONCE_S_LEN);
	wpa_hexdump(MSG_DEBUG, "EAP-SIM: (encr) AT_NONCE_S",
		    data->nonce_s, EAP_SIM_NONCE_S_LEN);

	eap_sim_derive_keys_reauth(data->counter,
				   data->reauth_id, data->reauth_id_len,
				   data->nonce_s, data->mk, data->msk,
				   data->emsk);
	eap_sim_clear_identities(data, CLEAR_REAUTH_ID | CLEAR_EAP_ID);
	eap_sim_learn_ids(data, &eattr);

	if (data->result_ind && attr->result_ind)
		data->use_result_ind = 1;

	if (data->state != FAILURE && data->state != RESULT_FAILURE) {
		eap_sim_state(data, data->use_result_ind ?
			      RESULT_SUCCESS : SUCCESS);
	}

	data->num_id_req = 0;
	data->num_notification = 0;
	if (data->counter > EAP_SIM_MAX_FAST_REAUTHS) {
		wpa_printf(MSG_DEBUG, "EAP-SIM: Maximum number of "
			   "fast reauths performed - force fullauth");
		eap_sim_clear_identities(data, CLEAR_REAUTH_ID | CLEAR_EAP_ID);
	}
	os_free(decrypted);
	return eap_sim_response_reauth(data, id, 0);
}


static struct wpabuf * eap_sim_process(struct eap_sm *sm, void *priv,
				       struct eap_method_ret *ret,
				       const struct wpabuf *reqData)
{
	struct eap_sim_data *data = priv;
	const struct eap_hdr *req;
	u8 subtype, id;
	struct wpabuf *res;
	const u8 *pos;
	struct eap_sim_attrs attr;
	size_t len;

	wpa_hexdump_buf(MSG_DEBUG, "EAP-SIM: EAP data", reqData);
	if (eap_get_config_identity(sm, &len) == NULL) {
		wpa_printf(MSG_INFO, "EAP-SIM: Identity not configured");
		eap_sm_request_identity(sm);
		ret->ignore = TRUE;
		return NULL;
	}

	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SIM, reqData, &len);
	if (pos == NULL || len < 1) {
		ret->ignore = TRUE;
		return NULL;
	}
	req = wpabuf_head(reqData);
	id = req->identifier;
	len = be_to_host16(req->length);

	ret->ignore = FALSE;
	ret->methodState = METHOD_MAY_CONT;
	ret->decision = DECISION_FAIL;
	ret->allowNotifications = TRUE;

	subtype = *pos++;
	wpa_printf(MSG_DEBUG, "EAP-SIM: Subtype=%d", subtype);
	pos += 2; /* Reserved */

	if (eap_sim_parse_attr(pos, wpabuf_head_u8(reqData) + len, &attr, 0,
			       0)) {
		res = eap_sim_client_error(data, id,
					   EAP_SIM_UNABLE_TO_PROCESS_PACKET);
		goto done;
	}

	switch (subtype) {
	case EAP_SIM_SUBTYPE_START:
		res = eap_sim_process_start(sm, data, id, &attr);
		break;
	case EAP_SIM_SUBTYPE_CHALLENGE:
		res = eap_sim_process_challenge(sm, data, id, reqData, &attr);
		break;
	case EAP_SIM_SUBTYPE_NOTIFICATION:
		res = eap_sim_process_notification(sm, data, id, reqData,
						   &attr);
		break;
	case EAP_SIM_SUBTYPE_REAUTHENTICATION:
		res = eap_sim_process_reauthentication(sm, data, id, reqData,
						       &attr);
		break;
	case EAP_SIM_SUBTYPE_CLIENT_ERROR:
		wpa_printf(MSG_DEBUG, "EAP-SIM: subtype Client-Error");
		res = eap_sim_client_error(data, id,
					   EAP_SIM_UNABLE_TO_PROCESS_PACKET);
		break;
	default:
		wpa_printf(MSG_DEBUG, "EAP-SIM: Unknown subtype=%d", subtype);
		res = eap_sim_client_error(data, id,
					   EAP_SIM_UNABLE_TO_PROCESS_PACKET);
		break;
	}

done:
	if (data->state == FAILURE) {
		ret->decision = DECISION_FAIL;
		ret->methodState = METHOD_DONE;
	} else if (data->state == SUCCESS) {
		ret->decision = data->use_result_ind ?
			DECISION_UNCOND_SUCC : DECISION_COND_SUCC;
		ret->methodState = data->use_result_ind ?
			METHOD_DONE : METHOD_MAY_CONT;
	} else if (data->state == RESULT_FAILURE)
		ret->methodState = METHOD_CONT;
	else if (data->state == RESULT_SUCCESS)
		ret->methodState = METHOD_CONT;

	if (ret->methodState == METHOD_DONE) {
		ret->allowNotifications = FALSE;
	}

	return res;
}


static Boolean eap_sim_has_reauth_data(struct eap_sm *sm, void *priv)
{
	struct eap_sim_data *data = priv;
	return data->pseudonym || data->reauth_id;
}


static void eap_sim_deinit_for_reauth(struct eap_sm *sm, void *priv)
{
	struct eap_sim_data *data = priv;
	eap_sim_clear_identities(data, CLEAR_EAP_ID);
	data->use_result_ind = 0;
}


static void * eap_sim_init_for_reauth(struct eap_sm *sm, void *priv)
{
	struct eap_sim_data *data = priv;
	if (os_get_random(data->nonce_mt, EAP_SIM_NONCE_MT_LEN)) {
		wpa_printf(MSG_WARNING, "EAP-SIM: Failed to get random data "
			   "for NONCE_MT");
		os_free(data);
		return NULL;
	}
	data->num_id_req = 0;
	data->num_notification = 0;
	eap_sim_state(data, CONTINUE);
	return priv;
}


static const u8 * eap_sim_get_identity(struct eap_sm *sm, void *priv,
				       size_t *len)
{
	struct eap_sim_data *data = priv;

	if (data->reauth_id) {
		*len = data->reauth_id_len;
		return data->reauth_id;
	}

	if (data->pseudonym) {
		*len = data->pseudonym_len;
		return data->pseudonym;
	}

	return NULL;
}


static Boolean eap_sim_isKeyAvailable(struct eap_sm *sm, void *priv)
{
	struct eap_sim_data *data = priv;
	return data->state == SUCCESS;
}


static u8 * eap_sim_getKey(struct eap_sm *sm, void *priv, size_t *len)
{
	struct eap_sim_data *data = priv;
	u8 *key;

	if (data->state != SUCCESS)
		return NULL;

	key = os_malloc(EAP_SIM_KEYING_DATA_LEN);
	if (key == NULL)
		return NULL;

	*len = EAP_SIM_KEYING_DATA_LEN;
	os_memcpy(key, data->msk, EAP_SIM_KEYING_DATA_LEN);

	return key;
}


static u8 * eap_sim_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
{
	struct eap_sim_data *data = priv;
	u8 *key;

	if (data->state != SUCCESS)
		return NULL;

	key = os_malloc(EAP_EMSK_LEN);
	if (key == NULL)
		return NULL;

	*len = EAP_EMSK_LEN;
	os_memcpy(key, data->emsk, EAP_EMSK_LEN);

	return key;
}


int eap_peer_sim_register(void)
{
	struct eap_method *eap;
	int ret;

	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
				    EAP_VENDOR_IETF, EAP_TYPE_SIM, "SIM");
	if (eap == NULL)
		return -1;

	eap->init = eap_sim_init;
	eap->deinit = eap_sim_deinit;
	eap->process = eap_sim_process;
	eap->isKeyAvailable = eap_sim_isKeyAvailable;
	eap->getKey = eap_sim_getKey;
	eap->has_reauth_data = eap_sim_has_reauth_data;
	eap->deinit_for_reauth = eap_sim_deinit_for_reauth;
	eap->init_for_reauth = eap_sim_init_for_reauth;
	eap->get_identity = eap_sim_get_identity;
	eap->get_emsk = eap_sim_get_emsk;

	ret = eap_peer_method_register(eap);
	if (ret)
		eap_peer_method_free(eap);
	return ret;
}