eap.c

freeradius-server-2.1.3.tar.gz安装源文件

			return RLM_MODULE_HANDLED;
		}

		/* Should never enter here */
		radlog(L_ERR, "rlm_eap: reply code %d is unknown, Rejecting the request.", reply->code);
		request->reply->code = PW_AUTHENTICATION_REJECT;
		reply->code = PW_EAP_FAILURE;
		rcode = RLM_MODULE_REJECT;
		break;
	}

	return rcode;
}

/*
 * Radius criteria, EAP-Message is invalid without Message-Authenticator
 * For EAP_START, send Access-Challenge with EAP Identity request.
 */
int eap_start(rlm_eap_t *inst, REQUEST *request)
{
	VALUE_PAIR *vp, *proxy;
	VALUE_PAIR *eap_msg;

	eap_msg = pairfind(request->packet->vps, PW_EAP_MESSAGE);
	if (eap_msg == NULL) {
		RDEBUG2("No EAP-Message, not doing EAP");
		return EAP_NOOP;
	}

	/*
	 *	Look for EAP-Type = None (FreeRADIUS specific attribute)
	 *	this allows you to NOT do EAP for some users.
	 */
	vp = pairfind(request->packet->vps, PW_EAP_TYPE);
	if (vp && vp->vp_integer == 0) {
		RDEBUG2("Found EAP-Message, but EAP-Type = None, so we're not doing EAP.");
		return EAP_NOOP;
	}

	/*
	 *	http://www.freeradius.org/rfc/rfc2869.html#EAP-Message
	 *
	 *	Checks for Message-Authenticator are handled by rad_recv().
	 */

	/*
	 *	Check for a Proxy-To-Realm.  Don't get excited over LOCAL
	 *	realms (sigh).
	 */
	proxy = pairfind(request->config_items, PW_PROXY_TO_REALM);
	if (proxy) {
		REALM *realm;

		/*
		 *	If it's a LOCAL realm, then we're not proxying
		 *	to it.
		 */
		realm = realm_find(proxy->vp_strvalue);
		if (realm && (realm->auth_pool == NULL)) {
			proxy = NULL;
		}
	}

	/*
	 *	Check the length before de-referencing the contents.
	 *
	 *	Lengths of zero are required by the RFC for EAP-Start,
	 *	but we've never seen them in practice.
	 *
	 *	Lengths of two are what we see in practice as
	 *	EAP-Starts.
	 */
	if ((eap_msg->length == 0) || (eap_msg->length == 2)) {
		EAP_DS *eap_ds;
		EAP_HANDLER handler;

		/*
		 *	It's a valid EAP-Start, but the request
		 *	was marked as being proxied.  So we don't
		 *	do EAP, as the home server will do it.
		 */
		if (proxy) {
		do_proxy:
			RDEBUG2("Request is supposed to be proxied to Realm %s.  Not doing EAP.", proxy->vp_strvalue);
			return EAP_NOOP;
		}

		RDEBUG2("Got EAP_START message");
		if ((eap_ds = eap_ds_alloc()) == NULL) {
			RDEBUG2("EAP Start failed in allocation");
			return EAP_FAIL;
		}

		/*
		 *	It's an EAP-Start packet.  Tell them to stop wasting
		 *	our time, and give us an EAP-Identity packet.
		 *
		 *	Hmm... we should probably check the contents of the
		 *	EAP-Start packet for something...
		 */
		eap_ds->request->code = PW_EAP_REQUEST;
		eap_ds->request->type.type = PW_EAP_IDENTITY;

		/*
		 *	We don't have a handler, but eap_compose needs one,
		 *	(for various reasons), so we fake it out here.
		 */
		memset(&handler, 0, sizeof(handler));
		handler.request = request;
		handler.eap_ds = eap_ds;

		eap_compose(&handler);

		eap_ds_free(&eap_ds);
		return EAP_FOUND;
	} /* end of handling EAP-Start */

	/*
	 *	The EAP packet header is 4 bytes, plus one byte of
	 *	EAP sub-type.  Short packets are discarded, unless
	 *	we're proxying.
	 */
	if (eap_msg->length < (EAP_HEADER_LEN + 1)) {
		if (proxy) goto do_proxy;

		RDEBUG2("Ignoring EAP-Message which is too short to be meaningful.");
		return EAP_FAIL;
	}

	/*
	 *	Create an EAP-Type containing the EAP-type
	 *	from the packet.
	 */
	vp = paircreate(PW_EAP_TYPE, PW_TYPE_INTEGER);
	if (vp) {
		vp->vp_integer = eap_msg->vp_octets[4];
		pairadd(&(request->packet->vps), vp);
	}

	/*
	 *	If the request was marked to be proxied, do it now.
	 *	This is done after checking for a valid length
	 *	(which may not be good), and after adding the EAP-Type
	 *	attribute.  This lets other modules selectively cancel
	 *	proxying based on EAP-Type.
	 */
	if (proxy) goto do_proxy;

	/*
	 *	From now on, we're supposed to be handling the
	 *	EAP packet.  We better understand it...
	 */

	/*
	 *	We're allowed only a few codes.  Request, Response,
	 *	Success, or Failure.
	 */
	if ((eap_msg->vp_octets[0] == 0) ||
	    (eap_msg->vp_octets[0] > PW_EAP_MAX_CODES)) {
		RDEBUG2("Unknown EAP packet");
	} else {
		RDEBUG2("EAP packet type %s id %d length %d",
		       eap_codes[eap_msg->vp_octets[0]],
		       eap_msg->vp_octets[1],
		       eap_msg->length);
	}

	/*
	 *	We handle request and responses.  The only other defined
	 *	codes are success and fail.  The client SHOULD NOT be
	 *	sending success/fail packets to us, as it doesn't make
	 *	sense.
	 */
	if ((eap_msg->vp_octets[0] != PW_EAP_REQUEST) &&
	    (eap_msg->vp_octets[0] != PW_EAP_RESPONSE)) {
		RDEBUG2("Ignoring EAP packet which we don't know how to handle.");
		return EAP_FAIL;
	}

	/*
	 *	We've been told to ignore unknown EAP types, AND it's
	 *	an unknown type.  Return "NOOP", which will cause the
	 *	eap_authorize() to return NOOP.
	 *
	 *	EAP-Identity, Notification, and NAK are all handled
	 *	internally, so they never have handlers.
	 */
	if ((eap_msg->vp_octets[4] >= PW_EAP_MD5) &&
	    inst->ignore_unknown_eap_types &&
	    ((eap_msg->vp_octets[4] == 0) ||
	     (eap_msg->vp_octets[4] > PW_EAP_MAX_TYPES) ||
	     (inst->types[eap_msg->vp_octets[4]] == NULL))) {
		RDEBUG2(" Ignoring Unknown EAP type");
		return EAP_NOOP;
	}

	/*
	 *	They're NAKing the EAP type we wanted to use, and
	 *	asking for one which we don't support.
	 *
	 *	NAK is code + id + length1 + length + NAK
	 *             + requested EAP type(s).
	 *
	 *	We know at this point that we can't handle the
	 *	request.  We could either return an EAP-Fail here, but
	 *	it's not too critical.
	 *
	 *	By returning "noop", we can ensure that authorize()
	 *	returns NOOP, and another module may choose to proxy
	 *	the request.
	 */
	if ((eap_msg->vp_octets[4] == PW_EAP_NAK) &&
	    (eap_msg->length >= (EAP_HEADER_LEN + 2)) &&
	    inst->ignore_unknown_eap_types &&
	    ((eap_msg->vp_octets[5] == 0) ||
	     (eap_msg->vp_octets[5] > PW_EAP_MAX_TYPES) ||
	     (inst->types[eap_msg->vp_octets[5]] == NULL))) {
		RDEBUG2("Ignoring NAK with request for unknown EAP type");
		return EAP_NOOP;
	}

	if ((eap_msg->vp_octets[4] == PW_EAP_TTLS) ||
	    (eap_msg->vp_octets[4] == PW_EAP_PEAP)) {
		RDEBUG2("Continuing tunnel setup.");
		return EAP_OK;
	}

	/*
	 *	Later EAP messages are longer than the 'start'
	 *	message, so if everything is OK, this function returns
	 *	'no start found', so that the rest of the EAP code can
	 *	use the State attribute to match this EAP-Message to
	 *	an ongoing conversation.
	 */
	RDEBUG2("No EAP Start, assuming it's an on-going EAP conversation");

	return EAP_NOTFOUND;
}

/*
 *	compose EAP FAILURE packet in EAP-Message
 */
void eap_fail(EAP_HANDLER *handler)
{
	/*
	 *	Delete any previous replies.
	 */
	pairdelete(&handler->request->reply->vps, PW_EAP_MESSAGE);
	pairdelete(&handler->request->reply->vps, PW_STATE);

	eap_packet_free(&handler->eap_ds->request);
	handler->eap_ds->request = eap_packet_alloc();

	handler->eap_ds->request->code = PW_EAP_FAILURE;
	eap_compose(handler);
}

/*
 *	compose EAP SUCCESS packet in EAP-Message
 */
void eap_success(EAP_HANDLER *handler)
{
	handler->eap_ds->request->code = PW_EAP_SUCCESS;
	eap_compose(handler);
}

/*
 * Basic EAP packet verfications & validations
 */
static int eap_validation(REQUEST *request, eap_packet_t *eap_packet)
{
	uint16_t len;

	memcpy(&len, eap_packet->length, sizeof(uint16_t));
	len = ntohs(len);

	/*
	 *	High level EAP packet checks
	 */
	if ((len <= EAP_HEADER_LEN) ||
 	    ((eap_packet->code != PW_EAP_RESPONSE) &&
 	     (eap_packet->code != PW_EAP_REQUEST)) ||
	    (eap_packet->data[0] <= 0) ||
	    (eap_packet->data[0] > PW_EAP_MAX_TYPES)) {

		radlog_request(L_AUTH, 0, request, 
			       "Badly formatted EAP Message: Ignoring the packet");
		return EAP_INVALID;
	}

	/* we don't expect notification, but we send it */
	if (eap_packet->data[0] == PW_EAP_NOTIFICATION) {
		radlog_request(L_AUTH, 0, request, "Got NOTIFICATION, "
			       "Ignoring the packet");
		return EAP_INVALID;
	}

	return EAP_VALID;
}


/*
 *  Get the user Identity only from EAP-Identity packets
 */
static char *eap_identity(REQUEST *request, eap_packet_t *eap_packet)
{
	int size;
	uint16_t len;
	char *identity;

	if ((eap_packet == NULL) ||
	    (eap_packet->code != PW_EAP_RESPONSE) ||
	    (eap_packet->data[0] != PW_EAP_IDENTITY)) {
		return NULL;
	}

	memcpy(&len, eap_packet->length, sizeof(uint16_t));
	len = ntohs(len);

	if ((len <= 5) || (eap_packet->data[1] == 0x00)) {
		RDEBUG("UserIdentity Unknown ");
		return NULL;
	}

	size = len - 5;
	identity = rad_malloc(size + 1);
	memcpy(identity, &eap_packet->data[1], size);
	identity[size] = '\0';

	return identity;
}


/*
 *	Create our Request-Response data structure with the eap packet
 */
static EAP_DS *eap_buildds(eap_packet_t **eap_packet_p)
{
	EAP_DS		*eap_ds = NULL;
	eap_packet_t	*eap_packet = *eap_packet_p;
	int		typelen;
	uint16_t	len;

	if ((eap_ds = eap_ds_alloc()) == NULL) {
		return NULL;
	}

	eap_ds->response->packet = (unsigned char *)eap_packet;
        eap_ds->response->code = eap_packet->code;
        eap_ds->response->id = eap_packet->id;
        eap_ds->response->type.type = eap_packet->data[0];

	memcpy(&len, eap_packet->length, sizeof(uint16_t));
	len = ntohs(len);
	eap_ds->response->length = len;

	/*
	 *	We've eaten the eap packet into the eap_ds.
	 */
	*eap_packet_p = NULL;

	/*
	 *	First 5 bytes in eap, are code + id + length(2) + type.
	 *
	 *	The rest is type-specific data.  We skip type while
	 *	getting typedata from data.
	 */
	typelen = len - 5/*code + id + length + type */;
	if (typelen > 0) {
		/*
		 *	Since the packet contains the complete
		 *	eap_packet, typedata will be a ptr in packet
		 *	to its typedata
		 */
		eap_ds->response->type.data = eap_ds->response->packet + 5/*code+id+length+type*/;
		eap_ds->response->type.length = typelen;
	} else {
		eap_ds->response->type.length = 0;
		eap_ds->response->type.data = NULL;
	}

	return eap_ds;
}


/*
 * If identity response then create a fresh handler & fill the identity
 * else handler MUST be in our list, get that.
 * This handler creation cannot fail
 *
 * username contains REQUEST->username which might have been stripped.
 * identity contains the one sent in EAP-Identity response
 */
EAP_HANDLER *eap_handler(rlm_eap_t *inst, eap_packet_t **eap_packet_p,
			 REQUEST *request)
{
	EAP_HANDLER	*handler = NULL;
	eap_packet_t	*eap_packet = *eap_packet_p;
	VALUE_PAIR	*vp;

	/*
	 *	Ensure it's a valid EAP-Request, or EAP-Response.
	 */
	if (eap_validation(request, eap_packet) == EAP_INVALID) {
		free(*eap_packet_p);
		*eap_packet_p = NULL;
		return NULL;
	}

	/*
	 *	EAP_HANDLER MUST be found in the list if it is not
	 *	EAP-Identity response
	 */
	if (eap_packet->data[0] != PW_EAP_IDENTITY) {
		handler = eaplist_find(inst, request, eap_packet);
		if (handler == NULL) {
			/* Either send EAP_Identity or EAP-Fail */
			RDEBUG("Either EAP-request timed out OR"
			       " EAP-response to an unknown EAP-request");
			free(*eap_packet_p);
			*eap_packet_p = NULL;
			return NULL;
		}

		/*
		 *	Even more paranoia.  Without this, some weird
		 *	clients could do crazy things.
		 *
		 *	It's ok to send EAP sub-type NAK in response
		 *	to a request for a particular type, but it's NOT
		 *	OK to blindly return data for another type.
		 */
		if ((eap_packet->data[0] != PW_EAP_NAK) &&
		    (eap_packet->data[0] != handler->eap_type)) {
			RDEBUG("Response appears to match, but EAP type is wrong.");
			free(*eap_packet_p);
			*eap_packet_p = NULL;
			return NULL;
		}

               vp = pairfind(request->packet->vps, PW_USER_NAME);
               if (!vp) {
                       /*
                        *	NAS did not set the User-Name
                        *	attribute, so we set it here and
                        *	prepend it to the beginning of the
                        *	request vps so that autz's work
                        *	correctly
			*/
		       RDEBUG2("Broken NAS did not set User-Name, setting from EAP Identity");
                       vp = pairmake("User-Name", handler->identity, T_OP_EQ);
                       if (vp == NULL) {
			       RDEBUG("Out of memory");
                               free(*eap_packet_p);
                               *eap_packet_p = NULL;
                               return NULL;
                       }
                       vp->next = request->packet->vps;
                       request->packet->vps = vp;

               } else {
                       /*
                        *      A little more paranoia.  If the NAS
                        *      *did* set the User-Name, and it doesn't
                        *      match the identity, (i.e. If they
                        *      change their User-Name part way through
                        *      the EAP transaction), then reject the
                        *      request as the NAS is doing something
                        *      funny.
			*/
                       if (strncmp(handler->identity, vp->vp_strvalue,
				   MAX_STRING_LEN) != 0) {
                               RDEBUG("Identity does not match User-Name.  Authentication failed.");
                               free(*eap_packet_p);
                               *eap_packet_p = NULL;
                               return NULL;
                       }
	       }
	} else {		/* packet was EAP identity */
		handler = eap_handler_alloc();
		if (handler == NULL) {
			RDEBUG("Out of memory.");
			free(*eap_packet_p);
			*eap_packet_p = NULL;
			return NULL;
		}

		/*
		 *	All fields in the handler are set to zero.
		 */
		handler->identity = eap_identity(request, eap_packet);
		if (handler->identity == NULL) {
			RDEBUG("Identity Unknown, authentication failed");
			free(*eap_packet_p);
			*eap_packet_p = NULL;
			eap_handler_free(handler);
			return NULL;
		}

               vp = pairfind(request->packet->vps, PW_USER_NAME);
               if (!vp) {
                       /*
                        *	NAS did not set the User-Name
                        *	attribute, so we set it here and
                        *	prepend it to the beginning of the
                        *	request vps so that autz's work
                        *	correctly
			*/
		       RDEBUG2("WARNING NAS did not set User-Name.  Setting it locally from EAP Identity");
                       vp = pairmake("User-Name", handler->identity, T_OP_EQ);
                       if (vp == NULL) {
                               RDEBUG("Out of memory");
                               free(*eap_packet_p);
                               *eap_packet_p = NULL;
			       eap_handler_free(handler);
                               return NULL;
                       }
                       vp->next = request->packet->vps;
                       request->packet->vps = vp;
               } else {
                       /*
                        *      Paranoia.  If the NAS *did* set the
                        *      User-Name, and it doesn't match the
                        *      identity, the NAS is doing something
                        *      funny, so reject the request.
			*/
                       if (strncmp(handler->identity, vp->vp_strvalue,
				   MAX_STRING_LEN) != 0) {
                               RDEBUG("Identity does not match User-Name, setting from EAP Identity.");
                               free(*eap_packet_p);
                               *eap_packet_p = NULL;
                               eap_handler_free(handler);
                               return NULL;
                       }
	       }
	}

	handler->eap_ds = eap_buildds(eap_packet_p);
	if (handler->eap_ds == NULL) {
		free(*eap_packet_p);
		*eap_packet_p = NULL;
		eap_handler_free(handler);
		return NULL;
	}

	handler->timestamp = request->timestamp;
	handler->request = request; /* LEAP needs this */
	return handler;
}