eap.c

freeradius-server-2.1.3.tar.gz安装源文件

/*
 * eap.c    rfc2284 & rfc2869 implementation
 *
 * Version:     $Id$
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 *
 * Copyright 2000-2003,2006  The FreeRADIUS server project
 * Copyright 2001  hereUare Communications, Inc. <[e-mail]>
 * Copyright 2003  Alan DeKok <[e-mail]>
 */
/*
 *  EAP PACKET FORMAT
 *  --- ------ ------
 *  0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Code      |  Identifier   |            Length             |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |    Data ...
 * +-+-+-+-+
 *
 *
 * EAP Request and Response Packet Format
 * --- ------- --- -------- ------ ------
 *  0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Code      |  Identifier   |            Length             |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |  Type-Data ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
 *
 *
 * EAP Success and Failure Packet Format
 * --- ------- --- ------- ------ ------
 *  0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Code      |  Identifier   |            Length             |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 */

#include <freeradius-devel/ident.h>
RCSID("$Id$")

#include "rlm_eap.h"

static const char *eap_codes[] = {
  "",				/* 0 is invalid */
  "request",
  "response",
  "success",
  "failure"
};

/*
 * Load all the required eap authentication types.
 * Get all the supported EAP-types from config file.
 */
int eaptype_load(EAP_TYPES **type, int eap_type, CONF_SECTION *cs)
{
	char		buffer[64];
	char		namebuf[64];
	const char	*eaptype_name;
	lt_dlhandle	handle;
	EAP_TYPES	*node;

	eaptype_name = eaptype_type2name(eap_type, namebuf, sizeof(namebuf));
	snprintf(buffer, sizeof(buffer), "rlm_eap_%s", eaptype_name);

	/* Link the loaded EAP-Type */
	handle = lt_dlopenext(buffer);
	if (handle == NULL) {
		radlog(L_ERR, "rlm_eap: Failed to link EAP-Type/%s: %s",
		       eaptype_name, lt_dlerror());
		return -1;
	}

	/* Make room for the EAP-Type */
	node = (EAP_TYPES *)malloc(sizeof(EAP_TYPES));
	if (node == NULL) {
		radlog(L_ERR, "rlm_eap: out of memory");
		return -1;
	}
	memset(node, 0, sizeof(*node));

	/* fill in the structure */
	node->handle = handle;
	node->cs = cs;

	/*
	 *	In general, this is a terrible idea.  It works here
	 *	solely because the eap_type2name function returns a
	 *	'static const char *' pointer sometimes, and we can
	 *	ONLY link to module which are named in that static
	 *	array.
	 */
	node->typename = eaptype_name;
	node->type_data = NULL;

	node->type = (EAP_TYPE *)lt_dlsym(node->handle, buffer);
	if (!node->type) {
		radlog(L_ERR, "rlm_eap: Failed linking to %s structure in %s: %s",
				buffer, eaptype_name, lt_dlerror());
		lt_dlclose(node->handle);	/* ignore any errors */
		free(node);
		return -1;
	}
	cf_log_module(cs, "Linked to sub-module %s", buffer);

	cf_log_module(cs, "Instantiating eap-%s", eaptype_name);

	if ((node->type->attach) &&
	    ((node->type->attach)(node->cs, &(node->type_data)) < 0)) {

		radlog(L_ERR, "rlm_eap: Failed to initialize type %s",
		       eaptype_name);
		lt_dlclose(node->handle);
		free(node);
		return -1;
	}

	*type = node;
	return 0;
}

/*
 * Call the appropriate handle with the right eap_type.
 */
static int eaptype_call(EAP_TYPES *atype, EAP_HANDLER *handler)
{
	int rcode = 1;
	REQUEST *request = handler->request;
	const char *module = request->module;

	RDEBUG2("processing type %s", atype->typename);
	request->module = atype->typename;

	rad_assert(atype != NULL);

	switch (handler->stage) {
	case INITIATE:
		if (!atype->type->initiate(atype->type_data, handler))
			rcode = 0;
		break;

	case AUTHORIZE:
		/*
		 *   The called function updates the EAP reply packet.
		 */
		if (!atype->type->authorize ||
		    !atype->type->authorize(atype->type_data, handler))
			rcode = 0;
		break;

	case AUTHENTICATE:
		/*
		 *   The called function updates the EAP reply packet.
		 */
		if (!atype->type->authenticate ||
		    !atype->type->authenticate(atype->type_data, handler))
			rcode = 0;
		break;

	default:
		/* Should never enter here */
		RDEBUG("Internal sanity check failed on eap_type");
		rcode = 0;
		break;
	}

	request->module = module;
	return rcode;
}

/*
 * Based on TYPE, call the appropriate EAP-type handler
 * Default to the configured EAP-Type
 * for all Unsupported EAP-Types
 */
int eaptype_select(rlm_eap_t *inst, EAP_HANDLER *handler)
{
	size_t		i;
	unsigned int	default_eap_type = inst->default_eap_type;
	eaptype_t	*eaptype;
	VALUE_PAIR	*vp;
	char		namebuf[64];
	const char	*eaptype_name;
	REQUEST		*request = handler->request;

	eaptype = &handler->eap_ds->response->type;

	/*
	 *	Don't trust anyone.
	 */
	if ((eaptype->type == 0) ||
	    (eaptype->type > PW_EAP_MAX_TYPES)) {
		RDEBUG2("Asked to select bad type");
		return EAP_INVALID;
	}

	/*
	 *	Multiple levels of nesting are invalid.
	 */
	if (handler->request->parent && handler->request->parent->parent) {
		RDEBUG2("Multiple levels of TLS nesting is invalid.");
		return EAP_INVALID;
	}

	/*
	 *	Figure out what to do.
	 */
	switch(eaptype->type) {
	case PW_EAP_IDENTITY:
		RDEBUG2("EAP Identity");

		/*
		 *	Allow per-user configuration of EAP types.
		 */
		vp = pairfind(handler->request->config_items,
			      PW_EAP_TYPE);
		if (vp) default_eap_type = vp->vp_integer;

	do_initiate:
		/*
		 *	Ensure it's valid.
		 */
		if ((default_eap_type < PW_EAP_MD5) ||
		    (default_eap_type > PW_EAP_MAX_TYPES) ||
		    (inst->types[default_eap_type] == NULL)) {
			RDEBUG2("No such EAP type %s",
			       eaptype_type2name(default_eap_type,
						 namebuf, sizeof(namebuf)));
			return EAP_INVALID;
		}

		handler->stage = INITIATE;
		handler->eap_type = default_eap_type;

		/*
		 *	Wild & crazy stuff!  For TTLS & PEAP, we
		 *	initiate a TLS session, and then pass that
		 *	session data to TTLS or PEAP for the
		 *	authenticate stage.
		 *
		 *	Handler->eap_type holds the TRUE type.
		 */
		if ((default_eap_type == PW_EAP_TTLS) ||
		    (default_eap_type == PW_EAP_PEAP)) {
			default_eap_type = PW_EAP_TLS;
		}

		if ((default_eap_type == PW_EAP_TNC) &&
		    !handler->request->parent) {
			RDEBUG2("ERROR: EAP-TNC must be run inside of a TLS method.");
			return EAP_INVALID;
		}

		if (eaptype_call(inst->types[default_eap_type],
				 handler) == 0) {
			RDEBUG2("Default EAP type %s failed in initiate",
			       eaptype_type2name(default_eap_type,
						 namebuf, sizeof(namebuf)));
			return EAP_INVALID;
		}
		break;

	case PW_EAP_NAK:
		/*
		 *	The NAK data is the preferred EAP type(s) of
		 *	the client.
		 *
		 *	RFC 3748 says to list one or more proposed
		 *	alternative types, one per octet, or to use
		 *	0 for no alternative.
		 */
		RDEBUG2("EAP NAK");

		/*
		 *	Delete old data, if necessary.
		 */
		if (handler->opaque && handler->free_opaque) {
			handler->free_opaque(handler->opaque);
			handler->free_opaque = NULL;
			handler->opaque = NULL;
		}

		if (eaptype->data == NULL) {
			RDEBUG2("Empty NAK packet, cannot decide what EAP type the client wants.");
			return EAP_INVALID;
		}

		/*
		 *	Pick one type out of the one they asked for,
		 *	as they may have asked for many.
		 */
		default_eap_type = 0;
		vp = pairfind(handler->request->config_items,
			      PW_EAP_TYPE);
		for (i = 0; i < eaptype->length; i++) {
			/*
			 *	It is invalid to request identity,
			 *	notification & nak in nak.
			 *
			 *	Type 0 is valid, and means there are no
			 *	common choices.
			 */
			if (eaptype->data[i] < PW_EAP_MD5) {
				RDEBUG2("NAK asked for bad type %d",
				       eaptype->data[i]);
				return EAP_INVALID;
			}

			if ((eaptype->data[i] > PW_EAP_MAX_TYPES) ||
			    !inst->types[eaptype->data[i]]) {
				RDEBUG2("NAK asked for unsupported type %d",
				       eaptype->data[i]);
				continue;
			}

			eaptype_name = eaptype_type2name(eaptype->data[i],
							 namebuf,
							 sizeof(namebuf));
			
			/*
			 *	Prevent a firestorm if the client is confused.
			 */
			if (handler->eap_type == eaptype->data[i]) {
				RDEBUG2("ERROR! Our request for %s was NAK'd with a request for %s.  Skipping the requested type.",
				       eaptype_name, eaptype_name);
				continue;
			}

			/*
			 *	Enforce per-user configuration of EAP
			 *	types.
			 */
			if (vp && (vp->vp_integer != eaptype->data[i])) {
				char	mynamebuf[64];
				RDEBUG2("Client wants %s, while we require %s.  Skipping the requested type.",
				       eaptype_name,
				       eaptype_type2name(vp->vp_integer,
							 mynamebuf,
							 sizeof(mynamebuf)));
				continue;
			}

			default_eap_type = eaptype->data[i];
			break;
		}

		/*
		 *	We probably want to return 'fail' here...
		 */
		if (!default_eap_type) {
			RDEBUG2("No common EAP types found.");
			return EAP_INVALID;
		}
		eaptype_name = eaptype_type2name(default_eap_type,
						 namebuf, sizeof(namebuf));
		RDEBUG2("EAP-NAK asked for EAP-Type/%s",
		       eaptype_name);

		goto do_initiate;
		break;

		/*
		 *	Key off of the configured sub-modules.
		 */
		default:
			eaptype_name = eaptype_type2name(eaptype->type,
							 namebuf,
							 sizeof(namebuf));
			RDEBUG2("EAP/%s", eaptype_name);

			/*
			 *	We haven't configured it, it doesn't exit.
			 */
			if (!inst->types[eaptype->type]) {
				RDEBUG2("EAP type %d is unsupported",
				       eaptype->type);
				return EAP_INVALID;
			}

			rad_assert(handler->stage == AUTHENTICATE);
			handler->eap_type = eaptype->type;
			if (eaptype_call(inst->types[eaptype->type],
					 handler) == 0) {
				RDEBUG2("Handler failed in EAP/%s",
				       eaptype_name);
				return EAP_INVALID;
			}
		break;
	}

	return EAP_OK;
}


/*
 *	compose EAP reply packet in EAP-Message attr of RADIUS.  If
 *	EAP exceeds 253, frame it in multiple EAP-Message attrs.
 *
 *	Set the RADIUS reply codes based on EAP request codes.  Append
 *	any additonal VPs to RADIUS reply
 */
int eap_compose(EAP_HANDLER *handler)
{
	VALUE_PAIR *vp;
	eap_packet_t *eap_packet;
	REQUEST *request = handler->request;
	EAP_DS *eap_ds = handler->eap_ds;
	EAP_PACKET *reply = eap_ds->request;
	int rcode;

	/*
	 *	The Id for the EAP packet to the NAS wasn't set.
	 *	Do so now.
	 *
	 *	LEAP requires the Id to be incremented on EAP-Success
	 *	in Stage 4, so that we can carry on the conversation
	 *	where the client asks us to authenticate ourselves
	 *	in stage 5.
	 */
	if (!eap_ds->set_request_id) {
		/*
		 *	Id serves to suppport request/response
		 *	retransmission in the EAP layer and as such
		 *	must be different for 'adjacent' packets
		 *	except in case of success/failure-replies.
		 *
		 *	RFC2716 (EAP-TLS) requires this to be
		 *	incremented, RFC2284 only makes the above-
		 *	mentioned restriction.
		 */
		reply->id = handler->eap_ds->response->id;

		switch (reply->code) {
			/*
			 *	The Id is a simple "ack" for success
			 *	and failure.
			 *
			 *	RFC 3748 section 4.2 says
			 *
			 *	... The Identifier field MUST match
			 *	the Identifier field of the Response
			 *	packet that it is sent in response
			 *	to.
			 */
		case PW_EAP_SUCCESS:
		case PW_EAP_FAILURE:
	    		break;

			/*
			 *	We've sent a response to their
			 *	request, the Id is incremented.
			 */
		default:
	    		++reply->id;
		}
	} else {
		RDEBUG2("Underlying EAP-Type set EAP ID to %d",
		       reply->id);
	}

	/*
	 *	For Request & Response packets, set the EAP sub-type,
	 *	if the EAP sub-module didn't already set it.
	 *
	 *	This allows the TLS module to be "morphic", and means
	 *	that the TTLS and PEAP modules can call it to do most
	 *	of their dirty work.
	 */
	if (((eap_ds->request->code == PW_EAP_REQUEST) ||
	     (eap_ds->request->code == PW_EAP_RESPONSE)) &&
	    (eap_ds->request->type.type == 0)) {
		rad_assert(handler->eap_type >= PW_EAP_MD5);
		rad_assert(handler->eap_type <= PW_EAP_MAX_TYPES);

		eap_ds->request->type.type = handler->eap_type;
	}

	/*
	 *	FIXME: We malloc memory for the eap packet, and then
	 *	immediately copy that data into VALUE_PAIRs.  This
	 *	could be done more efficiently...
	 */
	if (eap_wireformat(reply) == EAP_INVALID) {
		return RLM_MODULE_INVALID;
	}
	eap_packet = (eap_packet_t *)reply->packet;

	vp = eap_packet2vp(eap_packet);
	if (!vp) return RLM_MODULE_INVALID;
	pairadd(&(request->reply->vps), vp);

	/*
	 *	EAP-Message is always associated with
	 *	Message-Authenticator but not vice-versa.
	 *
	 *	Don't add a Message-Authenticator if it's already
	 *	there.
	 */
	vp = pairfind(request->reply->vps, PW_MESSAGE_AUTHENTICATOR);
	if (!vp) {
		vp = paircreate(PW_MESSAGE_AUTHENTICATOR, PW_TYPE_OCTETS);
		memset(vp->vp_octets, 0, AUTH_VECTOR_LEN);
		vp->length = AUTH_VECTOR_LEN;
		pairadd(&(request->reply->vps), vp);
	}

	/* Set request reply code, but only if it's not already set. */
	rcode = RLM_MODULE_OK;
	if (!request->reply->code) switch(reply->code) {
	case PW_EAP_RESPONSE:
		request->reply->code = PW_AUTHENTICATION_ACK;
		rcode = RLM_MODULE_HANDLED; /* leap weirdness */
		break;
	case PW_EAP_SUCCESS:
		request->reply->code = PW_AUTHENTICATION_ACK;
		rcode = RLM_MODULE_OK;
		break;
	case PW_EAP_FAILURE:
		request->reply->code = PW_AUTHENTICATION_REJECT;
		rcode = RLM_MODULE_REJECT;
		break;
	case PW_EAP_REQUEST:
		request->reply->code = PW_ACCESS_CHALLENGE;
		rcode = RLM_MODULE_HANDLED;
		break;
	default:
		/*
		 *	When we're pulling MS-CHAPv2 out of EAP-MS-CHAPv2,
		 *	we do so WITHOUT setting a reply code, as the
		 *	request is being proxied.
		 */
		if (request->options & RAD_REQUEST_OPTION_PROXY_EAP) {