eap_aka.c

IEEE 802.11a/b/g 服务器端AP

		   sm->identity[0] == EAP_AKA_PERMANENT_PREFIX) {
		identity = sm->identity;
		identity_len = sm->identity_len;
	} else {
		identity = eap_sim_db_get_permanent(sm->eap_sim_db_priv,
						    sm->identity,
						    sm->identity_len,
						    &identity_len);
		if (identity == NULL) {
			data->reauth = eap_sim_db_get_reauth_entry(
				sm->eap_sim_db_priv, sm->identity,
				sm->identity_len);
			if (data->reauth) {
				wpa_printf(MSG_DEBUG, "EAP-AKA: Using fast "
					   "re-authentication");
				identity = data->reauth->identity;
				identity_len = data->reauth->identity_len;
				data->counter = data->reauth->counter;
				os_memcpy(data->mk, data->reauth->mk,
					  EAP_SIM_MK_LEN);
			}
		}
	}

	if (identity == NULL ||
	    eap_sim_db_identity_known(sm->eap_sim_db_priv, sm->identity,
				      sm->identity_len) < 0) {
		if (before_identity) {
			wpa_printf(MSG_DEBUG, "EAP-AKA: Permanent user name "
				   "not known - send AKA-Identity request");
			eap_aka_state(data, IDENTITY);
			return;
		} else {
			wpa_printf(MSG_DEBUG, "EAP-AKA: Unknown whether the "
				   "permanent user name is known; try to use "
				   "it");
			/* eap_sim_db_get_aka_auth() will report failure, if
			 * this identity is not known. */
		}
	}

	wpa_hexdump_ascii(MSG_DEBUG, "EAP-AKA: Identity",
			  identity, identity_len);

	if (!after_reauth && data->reauth) {
		eap_aka_state(data, REAUTH);
		return;
	}

	res = eap_sim_db_get_aka_auth(sm->eap_sim_db_priv, identity,
				      identity_len, data->rand, data->autn,
				      data->ik, data->ck, data->res,
				      &data->res_len, sm);
	if (res == EAP_SIM_DB_PENDING) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: AKA authentication data "
			   "not yet available - pending request");
		sm->method_pending = METHOD_PENDING_WAIT;
		return;
	}

	data->reauth = NULL;
	data->counter = 0; /* reset re-auth counter since this is full auth */

	if (res != 0) {
		wpa_printf(MSG_INFO, "EAP-AKA: Failed to get AKA "
			   "authentication data for the peer");
		data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
		eap_aka_state(data, NOTIFICATION);
		return;
	}
	if (sm->method_pending == METHOD_PENDING_WAIT) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: AKA authentication data "
			   "available - abort pending wait");
		sm->method_pending = METHOD_PENDING_NONE;
	}

	identity_len = sm->identity_len;
	while (identity_len > 0 && sm->identity[identity_len - 1] == '\0') {
		wpa_printf(MSG_DEBUG, "EAP-AKA: Workaround - drop last null "
			   "character from identity");
		identity_len--;
	}
	wpa_hexdump_ascii(MSG_DEBUG, "EAP-AKA: Identity for MK derivation",
			  sm->identity, identity_len);

	eap_aka_derive_mk(sm->identity, identity_len, data->ik, data->ck,
			  data->mk);
	eap_sim_derive_keys(data->mk, data->k_encr, data->k_aut, data->msk,
			    data->emsk);

	eap_aka_state(data, CHALLENGE);
}


static void eap_aka_process_identity(struct eap_sm *sm,
				     struct eap_aka_data *data,
				     struct wpabuf *respData,
				     struct eap_sim_attrs *attr)
{
	wpa_printf(MSG_DEBUG, "EAP-AKA: Processing Identity");

	if (attr->mac || attr->iv || attr->encr_data) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Unexpected attribute "
			   "received in EAP-Response/AKA-Identity");
		data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
		eap_aka_state(data, NOTIFICATION);
		return;
	}

	if (attr->identity) {
		os_free(sm->identity);
		sm->identity = os_malloc(attr->identity_len);
		if (sm->identity) {
			os_memcpy(sm->identity, attr->identity,
				  attr->identity_len);
			sm->identity_len = attr->identity_len;
		}
	}

	eap_aka_determine_identity(sm, data, 0, 0);
	if (eap_get_id(respData) == data->pending_id) {
		data->pending_id = -1;
		eap_aka_add_id_msg(data, respData);
	}
}


static void eap_aka_process_challenge(struct eap_sm *sm,
				      struct eap_aka_data *data,
				      struct wpabuf *respData,
				      struct eap_sim_attrs *attr)
{
	const u8 *identity;
	size_t identity_len;

	wpa_printf(MSG_DEBUG, "EAP-AKA: Processing Challenge");

	if (attr->checkcode &&
	    eap_aka_verify_checkcode(data, attr->checkcode,
				     attr->checkcode_len)) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Invalid AT_CHECKCODE in the "
			   "message");
		data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
		eap_aka_state(data, NOTIFICATION);
		return;
	}
	if (attr->mac == NULL ||
	    eap_sim_verify_mac(data->k_aut, respData, attr->mac, NULL, 0)) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Challenge message "
			   "did not include valid AT_MAC");
		data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
		eap_aka_state(data, NOTIFICATION);
		return;
	}

	if (attr->res == NULL || attr->res_len != data->res_len ||
	    os_memcmp(attr->res, data->res, data->res_len) != 0) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Challenge message did not "
			   "include valid AT_RES");
		data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
		eap_aka_state(data, NOTIFICATION);
		return;
	}

	wpa_printf(MSG_DEBUG, "EAP-AKA: Challenge response includes the "
		   "correct AT_MAC");
	if (sm->eap_sim_aka_result_ind && attr->result_ind) {
		data->use_result_ind = 1;
		data->notification = EAP_SIM_SUCCESS;
		eap_aka_state(data, NOTIFICATION);
	} else
		eap_aka_state(data, SUCCESS);

	identity = eap_sim_db_get_permanent(sm->eap_sim_db_priv, sm->identity,
					    sm->identity_len, &identity_len);
	if (identity == NULL) {
		identity = sm->identity;
		identity_len = sm->identity_len;
	}

	if (data->next_pseudonym) {
		eap_sim_db_add_pseudonym(sm->eap_sim_db_priv, identity,
					 identity_len,
					 data->next_pseudonym);
		data->next_pseudonym = NULL;
	}
	if (data->next_reauth_id) {
		eap_sim_db_add_reauth(sm->eap_sim_db_priv, identity,
				      identity_len,
				      data->next_reauth_id, data->counter + 1,
				      data->mk);
		data->next_reauth_id = NULL;
	}
}


static void eap_aka_process_sync_failure(struct eap_sm *sm,
					 struct eap_aka_data *data,
					 struct wpabuf *respData,
					 struct eap_sim_attrs *attr)
{
	wpa_printf(MSG_DEBUG, "EAP-AKA: Processing Synchronization-Failure");

	if (attr->auts == NULL) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Synchronization-Failure "
			   "message did not include valid AT_AUTS");
		data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
		eap_aka_state(data, NOTIFICATION);
		return;
	}

	/* Avoid re-reporting AUTS when processing pending EAP packet by
	 * maintaining a local flag stating whether this AUTS has already been
	 * reported. */
	if (!data->auts_reported &&
	    eap_sim_db_resynchronize(sm->eap_sim_db_priv, sm->identity,
				     sm->identity_len, attr->auts,
				     data->rand)) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Resynchronization failed");
		data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
		eap_aka_state(data, NOTIFICATION);
		return;
	}
	data->auts_reported = 1;

	/* Try again after resynchronization */
	eap_aka_determine_identity(sm, data, 0, 0);
}


static void eap_aka_process_reauth(struct eap_sm *sm,
				   struct eap_aka_data *data,
				   struct wpabuf *respData,
				   struct eap_sim_attrs *attr)
{
	struct eap_sim_attrs eattr;
	u8 *decrypted = NULL;
	const u8 *identity, *id2;
	size_t identity_len, id2_len;

	wpa_printf(MSG_DEBUG, "EAP-AKA: Processing Reauthentication");

	if (attr->mac == NULL ||
	    eap_sim_verify_mac(data->k_aut, respData, attr->mac, data->nonce_s,
			       EAP_SIM_NONCE_S_LEN)) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Re-authentication message "
			   "did not include valid AT_MAC");
		goto fail;
	}

	if (attr->encr_data == NULL || attr->iv == NULL) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Reauthentication "
			   "message did not include encrypted data");
		goto fail;
	}

	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-AKA: Failed to parse encrypted "
			   "data from reauthentication message");
		goto fail;
	}

	if (eattr.counter != data->counter) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Re-authentication message "
			   "used incorrect counter %u, expected %u",
			   eattr.counter, data->counter);
		goto fail;
	}
	os_free(decrypted);
	decrypted = NULL;

	wpa_printf(MSG_DEBUG, "EAP-AKA: Re-authentication response includes "
		   "the correct AT_MAC");

	if (eattr.counter_too_small) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: Re-authentication response "
			   "included AT_COUNTER_TOO_SMALL - starting full "
			   "authentication");
		eap_aka_determine_identity(sm, data, 0, 1);
		return;
	}

	if (sm->eap_sim_aka_result_ind && attr->result_ind) {
		data->use_result_ind = 1;
		data->notification = EAP_SIM_SUCCESS;
		eap_aka_state(data, NOTIFICATION);
	} else
		eap_aka_state(data, SUCCESS);

	if (data->reauth) {
		identity = data->reauth->identity;
		identity_len = data->reauth->identity_len;
	} else {
		identity = sm->identity;
		identity_len = sm->identity_len;
	}

	id2 = eap_sim_db_get_permanent(sm->eap_sim_db_priv, identity,
				       identity_len, &id2_len);
	if (id2) {
		identity = id2;
		identity_len = id2_len;
	}

	if (data->next_pseudonym) {
		eap_sim_db_add_pseudonym(sm->eap_sim_db_priv, identity,
					 identity_len, data->next_pseudonym);
		data->next_pseudonym = NULL;
	}
	if (data->next_reauth_id) {
		eap_sim_db_add_reauth(sm->eap_sim_db_priv, identity,
				      identity_len, data->next_reauth_id,
				      data->counter + 1, data->mk);
		data->next_reauth_id = NULL;
	} else {
		eap_sim_db_remove_reauth(sm->eap_sim_db_priv, data->reauth);
		data->reauth = NULL;
	}

	return;

fail:
	data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
	eap_aka_state(data, NOTIFICATION);
	eap_sim_db_remove_reauth(sm->eap_sim_db_priv, data->reauth);
	data->reauth = NULL;
	os_free(decrypted);
}


static void eap_aka_process_client_error(struct eap_sm *sm,
					 struct eap_aka_data *data,
					 struct wpabuf *respData,
					 struct eap_sim_attrs *attr)
{
	wpa_printf(MSG_DEBUG, "EAP-AKA: Client reported error %d",
		   attr->client_error_code);
	if (data->notification == EAP_SIM_SUCCESS && data->use_result_ind)
		eap_aka_state(data, SUCCESS);
	else
		eap_aka_state(data, FAILURE);
}


static void eap_aka_process_authentication_reject(
	struct eap_sm *sm, struct eap_aka_data *data,
	struct wpabuf *respData, struct eap_sim_attrs *attr)
{
	wpa_printf(MSG_DEBUG, "EAP-AKA: Client rejected authentication");
	eap_aka_state(data, FAILURE);
}


static void eap_aka_process_notification(struct eap_sm *sm,
					 struct eap_aka_data *data,
					 struct wpabuf *respData,
					 struct eap_sim_attrs *attr)
{
	wpa_printf(MSG_DEBUG, "EAP-AKA: Client replied to notification");
	if (data->notification == EAP_SIM_SUCCESS && data->use_result_ind)
		eap_aka_state(data, SUCCESS);
	else
		eap_aka_state(data, FAILURE);
}


static void eap_aka_process(struct eap_sm *sm, void *priv,
			    struct wpabuf *respData)
{
	struct eap_aka_data *data = priv;
	const u8 *pos, *end;
	u8 subtype;
	size_t len;
	struct eap_sim_attrs attr;

	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_AKA, respData, &len);
	if (pos == NULL || len < 3)
		return;

	end = pos + len;
	subtype = *pos;
	pos += 3;

	if (eap_aka_subtype_ok(data, subtype)) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: Unrecognized or unexpected "
			   "EAP-AKA Subtype in EAP Response");
		data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
		eap_aka_state(data, NOTIFICATION);
		return;
	}

	if (eap_sim_parse_attr(pos, end, &attr, 1, 0)) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: Failed to parse attributes");
		data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
		eap_aka_state(data, NOTIFICATION);
		return;
	}

	if (subtype == EAP_AKA_SUBTYPE_CLIENT_ERROR) {
		eap_aka_process_client_error(sm, data, respData, &attr);
		return;
	}

	if (subtype == EAP_AKA_SUBTYPE_AUTHENTICATION_REJECT) {
		eap_aka_process_authentication_reject(sm, data, respData,
						      &attr);
		return;
	}

	switch (data->state) {
	case IDENTITY:
		eap_aka_process_identity(sm, data, respData, &attr);
		break;
	case CHALLENGE:
		if (subtype == EAP_AKA_SUBTYPE_SYNCHRONIZATION_FAILURE) {
			eap_aka_process_sync_failure(sm, data, respData,
						     &attr);
		} else {
			eap_aka_process_challenge(sm, data, respData, &attr);
		}
		break;
	case REAUTH:
		eap_aka_process_reauth(sm, data, respData, &attr);
		break;
	case NOTIFICATION:
		eap_aka_process_notification(sm, data, respData, &attr);
		break;
	default:
		wpa_printf(MSG_DEBUG, "EAP-AKA: Unknown state %d in "
			   "process", data->state);
		break;
	}
}


static Boolean eap_aka_isDone(struct eap_sm *sm, void *priv)
{
	struct eap_aka_data *data = priv;
	return data->state == SUCCESS || data->state == FAILURE;
}


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

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

	key = os_malloc(EAP_SIM_KEYING_DATA_LEN);
	if (key == NULL)
		return NULL;
	os_memcpy(key, data->msk, EAP_SIM_KEYING_DATA_LEN);
	*len = EAP_SIM_KEYING_DATA_LEN;
	return key;
}


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

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

	key = os_malloc(EAP_EMSK_LEN);
	if (key == NULL)
		return NULL;
	os_memcpy(key, data->emsk, EAP_EMSK_LEN);
	*len = EAP_EMSK_LEN;
	return key;
}


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


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

	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
				      EAP_VENDOR_IETF, EAP_TYPE_AKA, "AKA");
	if (eap == NULL)
		return -1;

	eap->init = eap_aka_init;
	eap->reset = eap_aka_reset;
	eap->buildReq = eap_aka_buildReq;
	eap->check = eap_aka_check;
	eap->process = eap_aka_process;
	eap->isDone = eap_aka_isDone;
	eap->getKey = eap_aka_getKey;
	eap->isSuccess = eap_aka_isSuccess;
	eap->get_emsk = eap_aka_get_emsk;

	ret = eap_server_method_register(eap);
	if (ret)
		eap_server_method_free(eap);
	return ret;
}