eap_aka.c

一个Linux下无线网卡的设置工具

	struct wpa_ssid *config = eap_get_config(sm);
	u8 *identity;
	size_t identity_len;
	int res;
	struct eap_sim_attrs eattr;

	wpa_printf(MSG_DEBUG, "EAP-AKA: subtype Challenge");
	data->reauth = 0;
	if (!attr->mac || !attr->rand || !attr->autn) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Challenge message "
			   "did not include%s%s%s",
			   !attr->mac ? " AT_MAC" : "",
			   !attr->rand ? " AT_RAND" : "",
			   !attr->autn ? " AT_AUTN" : "");
		return eap_aka_client_error(sm, data, req, respDataLen,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}
	memcpy(data->rand, attr->rand, AKA_RAND_LEN);
	memcpy(data->autn, attr->autn, AKA_AUTN_LEN);

	res = eap_aka_umts_auth(sm, data);
	if (res == -1) {
		wpa_printf(MSG_WARNING, "EAP-AKA: UMTS authentication "
			   "failed (AUTN)");
		return eap_aka_authentication_reject(sm, data, req,
						     respDataLen);
	} else if (res == -2) {
		wpa_printf(MSG_WARNING, "EAP-AKA: UMTS authentication "
			   "failed (AUTN seq# -> AUTS)");
		return eap_aka_synchronization_failure(sm, data, req,
						       respDataLen);
	} else if (res) {
		wpa_printf(MSG_WARNING, "EAP-AKA: UMTS authentication failed");
		return eap_aka_client_error(sm, data, req, respDataLen,
					    EAP_AKA_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 = config->identity;
		identity_len = config->identity_len;
	}
	wpa_hexdump_ascii(MSG_DEBUG, "EAP-AKA: Selected identity for MK "
			  "derivation", identity, identity_len);
	eap_aka_derive_mk(data, identity, identity_len);
	eap_sim_derive_keys(data->mk, data->k_encr, data->k_aut, data->msk);
	if (eap_sim_verify_mac(data->k_aut, (const u8 *) req, reqDataLen,
			       attr->mac, (u8 *) "", 0)) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Challenge message "
			   "used invalid AT_MAC");
		return eap_aka_client_error(sm, data, req, respDataLen,
					    EAP_AKA_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_aka_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_aka_client_error(
				sm, data, req, respDataLen,
				EAP_AKA_UNABLE_TO_PROCESS_PACKET);
		}
		eap_aka_learn_ids(data, &eattr);
		free(decrypted);
	}

	if (data->state != FAILURE)
		data->state = SUCCESS;

	data->num_id_req = 0;
	data->num_notification = 0;
	/* draft-arkko-pppext-eap-aka-12.txt 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_aka_response_challenge(sm, data, req, respDataLen);
}


static int eap_aka_process_notification_reauth(struct eap_aka_data *data,
					       const struct eap_hdr *req,
					       size_t reqDataLen,
					       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-AKA: 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-AKA: Failed to parse encrypted "
			   "data from notification message");
		return -1;
	}

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

	free(decrypted);
	return 0;
}


static int eap_aka_process_notification_auth(struct eap_aka_data *data,
					     const struct eap_hdr *req,
					     size_t reqDataLen,
					     struct eap_sim_attrs *attr)
{
	if (attr->mac == NULL) {
		wpa_printf(MSG_INFO, "EAP-AKA: no AT_MAC in after_auth "
			   "Notification message");
		return -1;
	}

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

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

	return 0;
}


static u8 * eap_aka_process_notification(struct eap_sm *sm,
					 struct eap_aka_data *data,
					 const struct eap_hdr *req,
					 size_t reqDataLen,
					 size_t *respDataLen,
					 struct eap_sim_attrs *attr)
{
	wpa_printf(MSG_DEBUG, "EAP-AKA: subtype Notification");
	if (data->num_notification > 0) {
		wpa_printf(MSG_INFO, "EAP-AKA: too many notification "
			   "rounds (only one allowed)");
		return eap_aka_client_error(sm, data, req, respDataLen,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}
	data->num_notification++;
	if (attr->notification == -1) {
		wpa_printf(MSG_INFO, "EAP-AKA: no AT_NOTIFICATION in "
			   "Notification message");
		return eap_aka_client_error(sm, data, req, respDataLen,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	if ((attr->notification & 0x4000) == 0 &&
	    eap_aka_process_notification_auth(data, req, reqDataLen, attr)) {
		return eap_aka_client_error(sm, data, req, respDataLen,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	eap_sim_report_notification(sm->msg_ctx, attr->notification, 1);
	if (attr->notification >= 0 && attr->notification < 32768) {
		data->state = FAILURE;
	}
	return eap_aka_response_notification(sm, data, req, respDataLen,
					     attr->notification);
}


static u8 * eap_aka_process_reauthentication(struct eap_sm *sm,
					     struct eap_aka_data *data,
					     const struct eap_hdr *req,
					     size_t reqDataLen,
					     size_t *respDataLen,
					     struct eap_sim_attrs *attr)
{
	struct eap_sim_attrs eattr;
	u8 *decrypted;

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

	if (data->reauth_id == NULL) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Server is trying "
			   "reauthentication, but no reauth_id available");
		return eap_aka_client_error(sm, data, req, respDataLen,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	data->reauth = 1;
	if (eap_sim_verify_mac(data->k_aut, (const u8 *) req, reqDataLen,
			       attr->mac, (u8 *) "", 0)) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Reauthentication "
			   "did not have valid AT_MAC");
		return eap_aka_client_error(sm, data, req, respDataLen,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	if (attr->encr_data == NULL || attr->iv == NULL) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Reauthentication "
			   "message did not include encrypted data");
		return eap_aka_client_error(sm, data, req, respDataLen,
					    EAP_AKA_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-AKA: Failed to parse encrypted "
			   "data from reauthentication message");
		return eap_aka_client_error(sm, data, req, respDataLen,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	if (eattr.nonce_s == NULL || eattr.counter < 0) {
		wpa_printf(MSG_INFO, "EAP-AKA: (encr) No%s%s in reauth packet",
			   !eattr.nonce_s ? " AT_NONCE_S" : "",
			   eattr.counter < 0 ? " AT_COUNTER" : "");
		free(decrypted);
		return eap_aka_client_error(sm, data, req, respDataLen,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	if (eattr.counter <= data->counter) {
		wpa_printf(MSG_INFO, "EAP-AKA: (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. */
		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;
		free(decrypted);
		return eap_aka_response_reauth(sm, data, req, respDataLen, 1);
	}
	data->counter = eattr.counter;

	memcpy(data->nonce_s, eattr.nonce_s, EAP_SIM_NONCE_S_LEN);
	wpa_hexdump(MSG_DEBUG, "EAP-AKA: (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);
	eap_aka_clear_identities(data, CLEAR_REAUTH_ID | CLEAR_EAP_ID);
	eap_aka_learn_ids(data, &eattr);

	if (data->state != FAILURE)
		data->state = SUCCESS;

	data->num_id_req = 0;
	data->num_notification = 0;
	if (data->counter > EAP_AKA_MAX_FAST_REAUTHS) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: Maximum number of "
			   "fast reauths performed - force fullauth");
		eap_aka_clear_identities(data, CLEAR_REAUTH_ID | CLEAR_EAP_ID);
	}
	free(decrypted);
	return eap_aka_response_reauth(sm, data, req, respDataLen, 0);
}


static u8 * eap_aka_process(struct eap_sm *sm, void *priv,
			    struct eap_method_ret *ret,
			    const u8 *reqData, size_t reqDataLen,
			    size_t *respDataLen)
{
	struct eap_aka_data *data = priv;
	struct wpa_ssid *config = eap_get_config(sm);
	const struct eap_hdr *req;
	u8 subtype, *res;
	const u8 *pos;
	struct eap_sim_attrs attr;
	size_t len;

	wpa_hexdump(MSG_DEBUG, "EAP-AKA: EAP data", reqData, reqDataLen);
	if (config == NULL || config->identity == NULL) {
		wpa_printf(MSG_INFO, "EAP-AKA: Identity not configured");
		eap_sm_request_identity(sm, config);
		ret->ignore = TRUE;
		return NULL;
	}

	pos = eap_hdr_validate(EAP_TYPE_AKA, reqData, reqDataLen, &len);
	if (pos == NULL || len < 1) {
		ret->ignore = TRUE;
		return NULL;
	}
	req = (const struct eap_hdr *) reqData;
	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-AKA: Subtype=%d", subtype);
	pos += 2; /* Reserved */

	if (eap_sim_parse_attr(pos, reqData + len, &attr, 1, 0)) {
		res = eap_aka_client_error(sm, data, req, respDataLen,
					   EAP_AKA_UNABLE_TO_PROCESS_PACKET);
		goto done;
	}

	switch (subtype) {
	case EAP_AKA_SUBTYPE_IDENTITY:
		res = eap_aka_process_identity(sm, data, req, len,
					       respDataLen, &attr);
		break;
	case EAP_AKA_SUBTYPE_CHALLENGE:
		res = eap_aka_process_challenge(sm, data, req, len,
						respDataLen, &attr);
		break;
	case EAP_AKA_SUBTYPE_NOTIFICATION:
		res = eap_aka_process_notification(sm, data, req, len,
						   respDataLen, &attr);
		break;
	case EAP_AKA_SUBTYPE_REAUTHENTICATION:
		res = eap_aka_process_reauthentication(sm, data, req, len,
						       respDataLen, &attr);
		break;
	case EAP_AKA_SUBTYPE_CLIENT_ERROR:
		wpa_printf(MSG_DEBUG, "EAP-AKA: subtype Client-Error");
		res = eap_aka_client_error(sm, data, req, respDataLen,
					   EAP_AKA_UNABLE_TO_PROCESS_PACKET);
		break;
	default:
		wpa_printf(MSG_DEBUG, "EAP-AKA: Unknown subtype=%d", subtype);
		res = eap_aka_client_error(sm, data, req, respDataLen,
					   EAP_AKA_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 = DECISION_COND_SUCC;
		ret->methodState = METHOD_DONE;
	}

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

	return res;
}


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


static void eap_aka_deinit_for_reauth(struct eap_sm *sm, void *priv)
{
	struct eap_aka_data *data = priv;
	eap_aka_clear_identities(data, CLEAR_EAP_ID);
}


static void * eap_aka_init_for_reauth(struct eap_sm *sm, void *priv)
{
	struct eap_aka_data *data = priv;
	data->num_id_req = 0;
	data->num_notification = 0;
	data->state = CONTINUE;
	return priv;
}


static const u8 * eap_aka_get_identity(struct eap_sm *sm, void *priv,
				       size_t *len)
{
	struct eap_aka_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_aka_isKeyAvailable(struct eap_sm *sm, void *priv)
{
	struct eap_aka_data *data = priv;
	return data->state == SUCCESS;
}


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

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

	return key;
}


const struct eap_method eap_method_aka =
{
	.method = EAP_TYPE_AKA,
	.name = "AKA",
	.init = eap_aka_init,
	.deinit = eap_aka_deinit,
	.process = eap_aka_process,
	.isKeyAvailable = eap_aka_isKeyAvailable,
	.getKey = eap_aka_getKey,
	.has_reauth_data = eap_aka_has_reauth_data,
	.deinit_for_reauth = eap_aka_deinit_for_reauth,
	.init_for_reauth = eap_aka_init_for_reauth,
	.get_identity = eap_aka_get_identity,
};