peap.c

freeradius-server-2.1.3.tar.gz安装源文件

/*
 * peap.c contains the interfaces that are called from eap
 *
 * 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 2003 Alan DeKok <[e-mail]>
 *   Copyright 2006 The FreeRADIUS server project
 */

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

#include "eap_peap.h"

/*
 *	Send protected EAP-Failure
 *
 *       Result-TLV = Failure
 */
static int eappeap_failure(EAP_HANDLER *handler, tls_session_t *tls_session)
{
	uint8_t tlv_packet[11];
	REQUEST *request = handler->request;

	RDEBUG2("FAILURE");

	tlv_packet[0] = PW_EAP_REQUEST;
	tlv_packet[1] = handler->eap_ds->response->id +1;
	tlv_packet[2] = 0;
	tlv_packet[3] = 11;	/* length of this packet */
	tlv_packet[4] = PW_EAP_TLV;
	tlv_packet[5] = 0x80;
	tlv_packet[6] = EAP_TLV_ACK_RESULT;
	tlv_packet[7] = 0;
	tlv_packet[8] = 2;	/* length of the data portion */
	tlv_packet[9] = 0;
	tlv_packet[10] = EAP_TLV_FAILURE;

	(tls_session->record_plus)(&tls_session->clean_in, tlv_packet, 11);

	/*
	 *	FIXME: Check the return code.
	 */
	tls_handshake_send(tls_session);

	return 1;
}


/*
 *	Send protected EAP-Success
 *
 *       Result-TLV = Success
 */
static int eappeap_success(EAP_HANDLER *handler, tls_session_t *tls_session)
{
	uint8_t tlv_packet[11];
	REQUEST *request = handler->request;

	RDEBUG2("SUCCESS");

	tlv_packet[0] = PW_EAP_REQUEST;
	tlv_packet[1] = handler->eap_ds->response->id +1;
	tlv_packet[2] = 0;
	tlv_packet[3] = 11;	/* length of this packet */
	tlv_packet[4] = PW_EAP_TLV;
	tlv_packet[5] = 0x80;	/* mandatory AVP */
	tlv_packet[6] = EAP_TLV_ACK_RESULT;
	tlv_packet[7] = 0;
	tlv_packet[8] = 2;	/* length of the data portion */
	tlv_packet[9] = 0;
	tlv_packet[10] = EAP_TLV_SUCCESS;

	(tls_session->record_plus)(&tls_session->clean_in, tlv_packet, 11);

	/*
	 *	FIXME: Check the return code.
	 */
	tls_handshake_send(tls_session);

	return 1;
}


/*
 *	Verify the tunneled EAP message.
 */
static int eapmessage_verify(REQUEST *request,
			     const uint8_t *data, unsigned int data_len)
{
	const eap_packet_t *eap_packet = (const eap_packet_t *) data;
	uint8_t eap_type;
	char buffer[256];

	if (!data || (data_len <= 1)) {
		return 0;
	}

	eap_type = *data;
	switch (eap_type) {
	case PW_EAP_IDENTITY:
		RDEBUG2("Identity - %*s",
		       data_len - 1, data + 1);
		return 1;
		break;

		/*
		 *	If the first byte of the packet is
		 *	EAP-Response, and the EAP data is a TLV,
		 *	then it looks OK...
		 */
	case PW_EAP_RESPONSE:
		if (eap_packet->data[0] == PW_EAP_TLV) {
			RDEBUG2("Received EAP-TLV response.");
			return 1;
		}
		RDEBUG2("Got something weird.");
		break;


		/*
		 *	We normally do Microsoft MS-CHAPv2 (26), versus
		 *	Cisco MS-CHAPv2 (29).
		 */
	case PW_EAP_MSCHAPV2:
	default:
		RDEBUG2("EAP type %s",
		       eaptype_type2name(eap_type,
					 buffer, sizeof(buffer)));
		return 1;
		break;
	}

	return 0;
}

/*
 *	Convert a pseudo-EAP packet to a list of VALUE_PAIR's.
 */
static VALUE_PAIR *eap2vp(REQUEST *request, EAP_DS *eap_ds,
			  const uint8_t *data, size_t data_len)
{
	size_t total;
	VALUE_PAIR *vp = NULL, *head, **tail;

	if (data_len > 65535) return NULL; /* paranoia */

	vp = paircreate(PW_EAP_MESSAGE, PW_TYPE_OCTETS);
	if (!vp) {
		RDEBUG2("Failure in creating VP");
		return NULL;
	}

	total = data_len;
	if (total > 249) total = 249;

	/*
	 *	Hand-build an EAP packet from the crap in PEAP version 0.
	 */
	vp->vp_octets[0] = PW_EAP_RESPONSE;
	vp->vp_octets[1] = eap_ds->response->id;
	vp->vp_octets[2] = (data_len + EAP_HEADER_LEN) >> 8;
	vp->vp_octets[3] = (data_len + EAP_HEADER_LEN) & 0xff;

	memcpy(vp->vp_octets + EAP_HEADER_LEN, data, total);
	vp->length = EAP_HEADER_LEN + total;

	head = vp;
	tail = &(vp->next);
	while (total < data_len) {
		int vp_len;


		vp = paircreate(PW_EAP_MESSAGE, PW_TYPE_OCTETS);
		if (!vp) {
			RDEBUG2("Failure in creating VP");
			pairfree(&head);
			return NULL;
		}
		vp_len = (data_len - total);
		if (vp_len > 253) vp_len = 253;

		memcpy(vp->vp_octets, data + total, vp_len);
		vp->length = vp_len;
		
		total += vp_len;
		*tail = vp;
		tail = &(vp->next);
	}

	return head;
}


/*
 *	Convert a list of VALUE_PAIR's to an EAP packet, through the
 *	simple expedient of dumping the EAP message
 */
static int vp2eap(tls_session_t *tls_session, VALUE_PAIR *vp)
{
	/*
	 *	Skip the id, code, and length.  Just write the EAP
	 *	type & data to the client.
	 */
#ifndef NDEBUG
	if ((debug_flag > 2) && fr_log_fp) {
		size_t i, total;
		VALUE_PAIR *this;

		total = 0;

		for (this = vp; this != NULL; this = this->next) {
			int start = 0;

			if (this == vp) start = EAP_HEADER_LEN;
			
			for (i = start; i < vp->length; i++) {
				if ((total & 0x0f) == 0) fprintf(fr_log_fp, "  PEAP tunnel data out %04x: ", total);

				fprintf(fr_log_fp, "%02x ", vp->vp_octets[i]);
				
				if ((total & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
				total++;
			}
		}
		if ((total & 0x0f) != 0) fprintf(fr_log_fp, "\n");
	}
#endif

	/*
	 *	Send the EAP data, WITHOUT the header.
	 */
	(tls_session->record_plus)(&tls_session->clean_in,
				   vp->vp_octets + EAP_HEADER_LEN,
				   vp->length - EAP_HEADER_LEN);
	
	/*
	 *	Send the rest of the EAP data.
	 */
	for (vp = vp->next; vp != NULL; vp = vp->next) {
		(tls_session->record_plus)(&tls_session->clean_in,
					   vp->vp_octets, vp->length);
	}

	tls_handshake_send(tls_session);

	return 1;
}


/*
 *	See if there's a TLV in the response.
 */
static int eappeap_check_tlv(REQUEST *request, const uint8_t *data)
{
	const eap_packet_t *eap_packet = (const eap_packet_t *) data;

	/*
	 *	Look for success or failure.
	 */
	if ((eap_packet->code == PW_EAP_RESPONSE) &&
	    (eap_packet->data[0] == PW_EAP_TLV)) {
		if (data[10] == EAP_TLV_SUCCESS) {
			return 1;
		}

		if (data[10] == EAP_TLV_FAILURE) {
			RDEBUG2("Client rejected our response.  The password is probably incorrect.");
			return 0;
		}
	}

	return 0;
}


/*
 *	Use a reply packet to determine what to do.
 */
static int process_reply(EAP_HANDLER *handler, tls_session_t *tls_session,
			 REQUEST *request, RADIUS_PACKET *reply)
{
	int rcode = RLM_MODULE_REJECT;
	VALUE_PAIR *vp;
	peap_tunnel_t *t = tls_session->opaque;

	if ((debug_flag > 0) && fr_log_fp) {
		RDEBUG("Got tunneled reply RADIUS code %d",
		       reply->code);

		debug_pair_list(reply->vps);
	}

	switch (reply->code) {
	case PW_AUTHENTICATION_ACK:
		RDEBUG2("Tunneled authentication was successful.");
		t->status = PEAP_STATUS_SENT_TLV_SUCCESS;
		eappeap_success(handler, tls_session);
		rcode = RLM_MODULE_HANDLED;

		/*
		 *	If we've been told to use the attributes from
		 *	the reply, then do so.
		 *
		 *	WARNING: This may leak information about the
		 *	tunneled user!
		 */
		if (t->use_tunneled_reply) {
			RDEBUG2("Saving tunneled attributes for later");

			/*
			 *	Clean up the tunneled reply.
			 */
			pairdelete(&reply->vps, PW_PROXY_STATE);
			pairdelete(&reply->vps, PW_EAP_MESSAGE);
			pairdelete(&reply->vps, PW_MESSAGE_AUTHENTICATOR);

			t->accept_vps = reply->vps;
			reply->vps = NULL;
		}
		break;

	case PW_AUTHENTICATION_REJECT:
		RDEBUG2("Tunneled authentication was rejected.");
		t->status = PEAP_STATUS_SENT_TLV_FAILURE;
		eappeap_failure(handler, tls_session);
		rcode = RLM_MODULE_HANDLED;
		break;

	case PW_ACCESS_CHALLENGE:
		RDEBUG2("Got tunneled Access-Challenge");

		/*
		 *	Keep the State attribute, if necessary.
		 *
		 *	Get rid of the old State, too.
		 */
		pairfree(&t->state);
		pairmove2(&t->state, &(reply->vps), PW_STATE);

		/*
		 *	PEAP takes only EAP-Message attributes inside
		 *	of the tunnel.  Any Reply-Message in the
		 *	Access-Challenge is ignored.
		 */
		vp = NULL;
		pairmove2(&vp, &(reply->vps), PW_EAP_MESSAGE);

		/*
		 *	Handle EAP-MSCHAP-V2, where Access-Accept's
		 *	from the home server may contain MS-CHAP-Success,
		 *	which the module turns into challenges, so that
		 *	the client may respond to the challenge with
		 *	an "ack" packet.
		 */
		if (t->home_access_accept && t->use_tunneled_reply) {
			RDEBUG2("Saving tunneled attributes for later");

			/*
			 *	Clean up the tunneled reply.
			 */
			pairdelete(&reply->vps, PW_PROXY_STATE);
			pairdelete(&reply->vps, PW_MESSAGE_AUTHENTICATOR);

			t->accept_vps = reply->vps;
			reply->vps = NULL;
		}

		/*
		 *	Handle the ACK, by tunneling any necessary reply
		 *	VP's back to the client.
		 */
		if (vp) {
			vp2eap(tls_session, vp);
			pairfree(&vp);
		}

		rcode = RLM_MODULE_HANDLED;
		break;

	default:
		RDEBUG2("Unknown RADIUS packet type %d: rejecting tunneled user", reply->code);
		rcode = RLM_MODULE_REJECT;
		break;
	}

	return rcode;
}


/*
 *	Do post-proxy processing,
 */
static int eappeap_postproxy(EAP_HANDLER *handler, void *data)
{
	int rcode;
	tls_session_t *tls_session = (tls_session_t *) data;
	REQUEST *fake, *request = handler->request;

	RDEBUG2("Passing reply from proxy back into the tunnel.");

	/*
	 *	If there was a fake request associated with the proxied
	 *	request, do more processing of it.
	 */
	fake = (REQUEST *) request_data_get(handler->request,
					    handler->request->proxy,
					    REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK);

	/*
	 *	Do the callback, if it exists, and if it was a success.
	 */
	if (fake && (handler->request->proxy_reply->code == PW_AUTHENTICATION_ACK)) {
		peap_tunnel_t *t = tls_session->opaque;

		t->home_access_accept = TRUE;

		/*
		 *	Terrible hacks.
		 */
		rad_assert(fake->packet == NULL);
		fake->packet = request->proxy;
		fake->packet->src_ipaddr = request->packet->src_ipaddr;
		request->proxy = NULL;

		rad_assert(fake->reply == NULL);
		fake->reply = request->proxy_reply;
		request->proxy_reply = NULL;

		if ((debug_flag > 0) && fr_log_fp) {
			fprintf(fr_log_fp, "server %s {\n", fake->server);
		}

		/*
		 *	Perform a post-auth stage, which will get the EAP
		 *	handler, too...
		 */
		fake->options &= ~RAD_REQUEST_OPTION_PROXY_EAP;
		RDEBUG2("Passing reply back for EAP-MS-CHAP-V2");
		rcode = module_post_proxy(0, fake);

		/*
		 *	FIXME: If rcode returns fail, do something
		 *	intelligent...
		 */
		rcode = rad_postauth(fake);

		if ((debug_flag > 0) && fr_log_fp) {
			fprintf(fr_log_fp, "} # server %s\n", fake->server);
			
			RDEBUG("Final reply from tunneled session code %d",
			       fake->reply->code);
		
			debug_pair_list(fake->reply->vps);
		}

		/*
		 *	Terrible hacks.
		 */
		request->proxy = fake->packet;
		fake->packet = NULL;
		request->proxy_reply = fake->reply;
		fake->reply = NULL;

		/*
		 *	And we're done with this request.
		 */

		switch (rcode) {
                case RLM_MODULE_FAIL:
			request_free(&fake);
			eaptls_fail(handler, 0);
			return 0;
			break;

                default:  /* Don't Do Anything */
			RDEBUG2("Got reply %d", request->proxy_reply->code);
			break;
		}
	}
	request_free(&fake);	/* robust if fake == NULL */