eap.c

hostapd源代码

/*
 * hostapd / EAP Standalone Authenticator state machine (RFC 4137)
 * Copyright (c) 2004-2006, Jouni Malinen <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "hostapd.h"
#include "sta_info.h"
#include "eap_i.h"
#include "state_machine.h"

#define STATE_MACHINE_DATA struct eap_sm
#define STATE_MACHINE_DEBUG_PREFIX "EAP"

#define EAP_MAX_AUTH_ROUNDS 50

static void eap_user_free(struct eap_user *user);


/* EAP state machines are described in RFC 4137 */

static int eap_sm_calculateTimeout(struct eap_sm *sm, int retransCount,
				   int eapSRTT, int eapRTTVAR,
				   int methodTimeout);
static void eap_sm_parseEapResp(struct eap_sm *sm, u8 *resp, size_t len);
static u8 * eap_sm_buildSuccess(struct eap_sm *sm, int id, size_t *len);
static u8 * eap_sm_buildFailure(struct eap_sm *sm, int id, size_t *len);
static int eap_sm_nextId(struct eap_sm *sm, int id);
static void eap_sm_Policy_update(struct eap_sm *sm, u8 *nak_list, size_t len);
static EapType eap_sm_Policy_getNextMethod(struct eap_sm *sm, int *vendor);
static int eap_sm_Policy_getDecision(struct eap_sm *sm);
static Boolean eap_sm_Policy_doPickUp(struct eap_sm *sm, EapType method);


static Boolean eapol_get_bool(struct eap_sm *sm, enum eapol_bool_var var)
{
	return sm->eapol_cb->get_bool(sm->eapol_ctx, var);
}


static void eapol_set_bool(struct eap_sm *sm, enum eapol_bool_var var,
			   Boolean value)
{
	sm->eapol_cb->set_bool(sm->eapol_ctx, var, value);
}


static void eapol_set_eapReqData(struct eap_sm *sm,
				 const u8 *eapReqData, size_t eapReqDataLen)
{
	wpa_hexdump(MSG_MSGDUMP, "EAP: eapReqData -> EAPOL",
		    sm->eapReqData, sm->eapReqDataLen);
	sm->eapol_cb->set_eapReqData(sm->eapol_ctx, eapReqData, eapReqDataLen);
}


static void eapol_set_eapKeyData(struct eap_sm *sm,
				 const u8 *eapKeyData, size_t eapKeyDataLen)
{
	wpa_hexdump(MSG_MSGDUMP, "EAP: eapKeyData -> EAPOL",
		    sm->eapKeyData, sm->eapKeyDataLen);
	sm->eapol_cb->set_eapKeyData(sm->eapol_ctx, eapKeyData, eapKeyDataLen);
}


/**
 * eap_user_get - Fetch user information from the database
 * @sm: Pointer to EAP state machine allocated with eap_sm_init()
 * @identity: Identity (User-Name) of the user
 * @identity_len: Length of identity in bytes
 * @phase2: 0 = EAP phase1 user, 1 = EAP phase2 (tunneled) user
 * Returns: 0 on success, or -1 on failure
 *
 * This function is used to fetch user information for EAP. The user will be
 * selected based on the specified identity. sm->user and
 * sm->user_eap_method_index are updated for the new user when a matching user
 * is found. sm->user can be used to get user information (e.g., password).
 */
int eap_user_get(struct eap_sm *sm, const u8 *identity, size_t identity_len,
		 int phase2)
{
	struct eap_user *user;

	if (sm == NULL || sm->eapol_cb == NULL ||
	    sm->eapol_cb->get_eap_user == NULL)
		return -1;

	eap_user_free(sm->user);
	sm->user = NULL;

	user = wpa_zalloc(sizeof(*user));
	if (user == NULL)
	    return -1;

	if (sm->eapol_cb->get_eap_user(sm->eapol_ctx, identity,
				       identity_len, phase2, user) != 0) {
		eap_user_free(user);
		return -1;
	}

	sm->user = user;
	sm->user_eap_method_index = 0;

	return 0;
}


SM_STATE(EAP, DISABLED)
{
	SM_ENTRY(EAP, DISABLED);
	sm->num_rounds = 0;
}


SM_STATE(EAP, INITIALIZE)
{
	SM_ENTRY(EAP, INITIALIZE);

	sm->currentId = -1;
	eapol_set_bool(sm, EAPOL_eapSuccess, FALSE);
	eapol_set_bool(sm, EAPOL_eapFail, FALSE);
	eapol_set_bool(sm, EAPOL_eapTimeout, FALSE);
	free(sm->eapKeyData);
	sm->eapKeyData = NULL;
	sm->eapKeyDataLen = 0;
	/* eapKeyAvailable = FALSE */
	eapol_set_bool(sm, EAPOL_eapRestart, FALSE);

	/*
	 * This is not defined in RFC 4137, but method state needs to be
	 * reseted here so that it does not remain in success state when
	 * re-authentication starts.
	 */
	if (sm->m && sm->eap_method_priv) {
		sm->m->reset(sm, sm->eap_method_priv);
		sm->eap_method_priv = NULL;
	}
	sm->m = NULL;
	sm->user_eap_method_index = 0;

	if (sm->backend_auth) {
		sm->currentMethod = EAP_TYPE_NONE;
		/* parse rxResp, respId, respMethod */
		eap_sm_parseEapResp(sm, sm->eapRespData, sm->eapRespDataLen);
		if (sm->rxResp) {
			sm->currentId = sm->respId;
		}
	}
	sm->num_rounds = 0;
	sm->method_pending = METHOD_PENDING_NONE;
}


SM_STATE(EAP, PICK_UP_METHOD)
{
	SM_ENTRY(EAP, PICK_UP_METHOD);

	if (eap_sm_Policy_doPickUp(sm, sm->respMethod)) {
		sm->currentMethod = sm->respMethod;
		if (sm->m && sm->eap_method_priv) {
			sm->m->reset(sm, sm->eap_method_priv);
			sm->eap_method_priv = NULL;
		}
		sm->m = eap_sm_get_eap_methods(EAP_VENDOR_IETF,
					       sm->currentMethod);
		if (sm->m && sm->m->initPickUp) {
			sm->eap_method_priv = sm->m->initPickUp(sm);
			if (sm->eap_method_priv == NULL) {
				wpa_printf(MSG_DEBUG, "EAP: Failed to "
					   "initialize EAP method %d",
					   sm->currentMethod);
				sm->m = NULL;
				sm->currentMethod = EAP_TYPE_NONE;
			}
		} else {
			sm->m = NULL;
			sm->currentMethod = EAP_TYPE_NONE;
		}
	}
}


SM_STATE(EAP, IDLE)
{
	SM_ENTRY(EAP, IDLE);

	sm->retransWhile = eap_sm_calculateTimeout(sm, sm->retransCount,
						   sm->eapSRTT, sm->eapRTTVAR,
						   sm->methodTimeout);
}


SM_STATE(EAP, RETRANSMIT)
{
	SM_ENTRY(EAP, RETRANSMIT);

	/* TODO: Is this needed since EAPOL state machines take care of
	 * retransmit? */
}


SM_STATE(EAP, RECEIVED)
{
	SM_ENTRY(EAP, RECEIVED);

	/* parse rxResp, respId, respMethod */
	eap_sm_parseEapResp(sm, sm->eapRespData, sm->eapRespDataLen);
	sm->num_rounds++;
}


SM_STATE(EAP, DISCARD)
{
	SM_ENTRY(EAP, DISCARD);
	eapol_set_bool(sm, EAPOL_eapResp, FALSE);
	eapol_set_bool(sm, EAPOL_eapNoReq, TRUE);
}


SM_STATE(EAP, SEND_REQUEST)
{
	SM_ENTRY(EAP, SEND_REQUEST);

	sm->retransCount = 0;
	if (sm->eapReqData) {
		eapol_set_eapReqData(sm, sm->eapReqData, sm->eapReqDataLen);
		free(sm->lastReqData);
		sm->lastReqData = sm->eapReqData;
		sm->lastReqDataLen = sm->eapReqDataLen;
		sm->eapReqData = NULL;
		sm->eapReqDataLen = 0;
		eapol_set_bool(sm, EAPOL_eapResp, FALSE);
		eapol_set_bool(sm, EAPOL_eapReq, TRUE);
	} else {
		wpa_printf(MSG_INFO, "EAP: SEND_REQUEST - no eapReqData");
		eapol_set_bool(sm, EAPOL_eapResp, FALSE);
		eapol_set_bool(sm, EAPOL_eapReq, FALSE);
		eapol_set_bool(sm, EAPOL_eapNoReq, TRUE);
	}
}


SM_STATE(EAP, INTEGRITY_CHECK)
{
	SM_ENTRY(EAP, INTEGRITY_CHECK);

	if (sm->m->check) {
		sm->ignore = sm->m->check(sm, sm->eap_method_priv,
					  sm->eapRespData, sm->eapRespDataLen);
	}
}


SM_STATE(EAP, METHOD_REQUEST)
{
	SM_ENTRY(EAP, METHOD_REQUEST);

	if (sm->m == NULL) {
		wpa_printf(MSG_DEBUG, "EAP: method not initialized");
		return;
	}

	sm->currentId = eap_sm_nextId(sm, sm->currentId);
	wpa_printf(MSG_DEBUG, "EAP: building EAP-Request: Identifier %d",
		   sm->currentId);
	sm->lastId = sm->currentId;
	free(sm->eapReqData);
	sm->eapReqData = sm->m->buildReq(sm, sm->eap_method_priv,
					 sm->currentId, &sm->eapReqDataLen);
	if (sm->m->getTimeout)
		sm->methodTimeout = sm->m->getTimeout(sm, sm->eap_method_priv);
	else
		sm->methodTimeout = 0;
}


SM_STATE(EAP, METHOD_RESPONSE)
{
	SM_ENTRY(EAP, METHOD_RESPONSE);

	sm->m->process(sm, sm->eap_method_priv, sm->eapRespData,
		       sm->eapRespDataLen);
	if (sm->m->isDone(sm, sm->eap_method_priv)) {
		eap_sm_Policy_update(sm, NULL, 0);
		free(sm->eapKeyData);
		if (sm->m->getKey) {
			sm->eapKeyData = sm->m->getKey(sm, sm->eap_method_priv,
						       &sm->eapKeyDataLen);
		} else {
			sm->eapKeyData = NULL;
			sm->eapKeyDataLen = 0;
		}
		sm->methodState = METHOD_END;
	} else {
		sm->methodState = METHOD_CONTINUE;
	}
}


SM_STATE(EAP, PROPOSE_METHOD)
{
	int vendor;
	EapType type;

	SM_ENTRY(EAP, PROPOSE_METHOD);

	type = eap_sm_Policy_getNextMethod(sm, &vendor);
	if (vendor == EAP_VENDOR_IETF)
		sm->currentMethod = type;
	else
		sm->currentMethod = EAP_TYPE_EXPANDED;
	if (sm->m && sm->eap_method_priv) {
		sm->m->reset(sm, sm->eap_method_priv);
		sm->eap_method_priv = NULL;
	}
	sm->m = eap_sm_get_eap_methods(vendor, type);
	if (sm->m) {
		sm->eap_method_priv = sm->m->init(sm);
		if (sm->eap_method_priv == NULL) {
			wpa_printf(MSG_DEBUG, "EAP: Failed to initialize EAP "
				   "method %d", sm->currentMethod);
			sm->m = NULL;
			sm->currentMethod = EAP_TYPE_NONE;
		}
	}
	if (sm->currentMethod == EAP_TYPE_IDENTITY ||
	    sm->currentMethod == EAP_TYPE_NOTIFICATION)
		sm->methodState = METHOD_CONTINUE;
	else
		sm->methodState = METHOD_PROPOSED;
}


SM_STATE(EAP, NAK)
{
	struct eap_hdr *nak;
	size_t len = 0;
	u8 *pos, *nak_list = NULL;

	SM_ENTRY(EAP, NAK);

	if (sm->eap_method_priv) {
		sm->m->reset(sm, sm->eap_method_priv);
		sm->eap_method_priv = NULL;
	}
	sm->m = NULL;

	nak = (struct eap_hdr *) sm->eapRespData;
	if (nak && sm->eapRespDataLen > sizeof(*nak)) {
		len = ntohs(nak->length);
		if (len > sm->eapRespDataLen)
			len = sm->eapRespDataLen;
		pos = (u8 *) (nak + 1);
		len -= sizeof(*nak);
		if (*pos == EAP_TYPE_NAK) {
			pos++;
			len--;
			nak_list = pos;
		}
	}
	eap_sm_Policy_update(sm, nak_list, len);
}


SM_STATE(EAP, SELECT_ACTION)
{
	SM_ENTRY(EAP, SELECT_ACTION);

	sm->decision = eap_sm_Policy_getDecision(sm);
}


SM_STATE(EAP, TIMEOUT_FAILURE)
{
	SM_ENTRY(EAP, TIMEOUT_FAILURE);

	eapol_set_bool(sm, EAPOL_eapTimeout, TRUE);
}


SM_STATE(EAP, FAILURE)
{
	SM_ENTRY(EAP, FAILURE);

	free(sm->eapReqData);
	sm->eapReqData = eap_sm_buildFailure(sm, sm->currentId,
					     &sm->eapReqDataLen);
	if (sm->eapReqData) {
		eapol_set_eapReqData(sm, sm->eapReqData, sm->eapReqDataLen);
		free(sm->eapReqData);
		sm->eapReqData = NULL;
		sm->eapReqDataLen = 0;
	}
	free(sm->lastReqData);
	sm->lastReqData = NULL;
	sm->lastReqDataLen = 0;
	eapol_set_bool(sm, EAPOL_eapFail, TRUE);
}


SM_STATE(EAP, SUCCESS)
{
	SM_ENTRY(EAP, SUCCESS);

	free(sm->eapReqData);
	sm->eapReqData = eap_sm_buildSuccess(sm, sm->currentId,
					     &sm->eapReqDataLen);
	if (sm->eapReqData) {
		eapol_set_eapReqData(sm, sm->eapReqData, sm->eapReqDataLen);
		free(sm->eapReqData);
		sm->eapReqData = NULL;
		sm->eapReqDataLen = 0;
	}
	free(sm->lastReqData);
	sm->lastReqData = NULL;
	sm->lastReqDataLen = 0;
	if (sm->eapKeyData) {
		eapol_set_eapKeyData(sm, sm->eapKeyData, sm->eapKeyDataLen);
	}
	eapol_set_bool(sm, EAPOL_eapSuccess, TRUE);
}


SM_STEP(EAP)
{
	if (eapol_get_bool(sm, EAPOL_eapRestart) &&
	    eapol_get_bool(sm, EAPOL_portEnabled))
		SM_ENTER_GLOBAL(EAP, INITIALIZE);
	else if (!eapol_get_bool(sm, EAPOL_portEnabled))
		SM_ENTER_GLOBAL(EAP, DISABLED);
	else if (sm->num_rounds > EAP_MAX_AUTH_ROUNDS) {
		if (sm->num_rounds == EAP_MAX_AUTH_ROUNDS + 1) {
			wpa_printf(MSG_DEBUG, "EAP: more than %d "
				   "authentication rounds - abort",
				   EAP_MAX_AUTH_ROUNDS);
			sm->num_rounds++;
			SM_ENTER_GLOBAL(EAP, FAILURE);
		}
	} else switch (sm->EAP_state) {
	case EAP_INITIALIZE:
		if (sm->backend_auth) {
			if (!sm->rxResp)
				SM_ENTER(EAP, SELECT_ACTION);
			else if (sm->rxResp &&
				 (sm->respMethod == EAP_TYPE_NAK ||
				  (sm->respMethod == EAP_TYPE_EXPANDED &&
				   sm->respVendor == EAP_VENDOR_IETF &&
				   sm->respVendorMethod == EAP_TYPE_NAK)))
				SM_ENTER(EAP, NAK);
			else
				SM_ENTER(EAP, PICK_UP_METHOD);
		} else {
			SM_ENTER(EAP, SELECT_ACTION);
		}
		break;
	case EAP_PICK_UP_METHOD:
		if (sm->currentMethod == EAP_TYPE_NONE) {
			SM_ENTER(EAP, SELECT_ACTION);
		} else {
			SM_ENTER(EAP, METHOD_RESPONSE);
		}
		break;
	case EAP_DISABLED:
		if (eapol_get_bool(sm, EAPOL_portEnabled))
			SM_ENTER(EAP, INITIALIZE);
		break;
	case EAP_IDLE:
		if (sm->retransWhile == 0)
			SM_ENTER(EAP, RETRANSMIT);
		else if (eapol_get_bool(sm, EAPOL_eapResp))
			SM_ENTER(EAP, RECEIVED);
		break;
	case EAP_RETRANSMIT:
		if (sm->retransCount > sm->MaxRetrans)
			SM_ENTER(EAP, TIMEOUT_FAILURE);
		else
			SM_ENTER(EAP, IDLE);
		break;
	case EAP_RECEIVED:
		if (sm->rxResp && (sm->respId == sm->currentId) &&
		    (sm->respMethod == EAP_TYPE_NAK ||
		     (sm->respMethod == EAP_TYPE_EXPANDED &&
		      sm->respVendor == EAP_VENDOR_IETF &&
		      sm->respVendorMethod == EAP_TYPE_NAK))
		    && (sm->methodState == METHOD_PROPOSED))
			SM_ENTER(EAP, NAK);
		else if (sm->rxResp && (sm->respId == sm->currentId) &&
			 ((sm->respMethod == sm->currentMethod) ||
			  (sm->respMethod == EAP_TYPE_EXPANDED &&
			   sm->respVendor == EAP_VENDOR_IETF &&
			   sm->respVendorMethod == sm->currentMethod)))
			SM_ENTER(EAP, INTEGRITY_CHECK);
		else {
			wpa_printf(MSG_DEBUG, "EAP: RECEIVED->DISCARD: "
				   "rxResp=%d respId=%d currentId=%d "
				   "respMethod=%d currentMethod=%d",
				   sm->rxResp, sm->respId, sm->currentId,
				   sm->respMethod, sm->currentMethod);
			SM_ENTER(EAP, DISCARD);
		}
		break;
	case EAP_DISCARD:
		SM_ENTER(EAP, IDLE);
		break;
	case EAP_SEND_REQUEST:
		SM_ENTER(EAP, IDLE);
		break;
	case EAP_INTEGRITY_CHECK:
		if (sm->ignore)
			SM_ENTER(EAP, DISCARD);
		else
			SM_ENTER(EAP, METHOD_RESPONSE);
		break;
	case EAP_METHOD_REQUEST:
		SM_ENTER(EAP, SEND_REQUEST);
		break;
	case EAP_METHOD_RESPONSE:
		/*
		 * Note: Mechanism to allow EAP methods to wait while going
		 * through pending processing is an extension to RFC 4137
		 * which only defines the transits to SELECT_ACTION and
		 * METHOD_REQUEST from this METHOD_RESPONSE state.
		 */
		if (sm->methodState == METHOD_END)
			SM_ENTER(EAP, SELECT_ACTION);
		else if (sm->method_pending == METHOD_PENDING_WAIT) {
			wpa_printf(MSG_DEBUG, "EAP: Method has pending "
				   "processing - wait before proceeding to "
				   "METHOD_REQUEST state");
		} else if (sm->method_pending == METHOD_PENDING_CONT) {
			wpa_printf(MSG_DEBUG, "EAP: Method has completed "
				   "pending processing - reprocess pending "
				   "EAP message");
			sm->method_pending = METHOD_PENDING_NONE;
			SM_ENTER(EAP, METHOD_RESPONSE);
		} else
			SM_ENTER(EAP, METHOD_REQUEST);
		break;
	case EAP_PROPOSE_METHOD:
		/*
		 * Note: Mechanism to allow EAP methods to wait while going
		 * through pending processing is an extension to RFC 4137
		 * which only defines the transit to METHOD_REQUEST from this
		 * PROPOSE_METHOD state.
		 */
		if (sm->method_pending == METHOD_PENDING_WAIT) {
			wpa_printf(MSG_DEBUG, "EAP: Method has pending "
				   "processing - wait before proceeding to "
				   "METHOD_REQUEST state");
			if (sm->user_eap_method_index > 0)
				sm->user_eap_method_index--;
		} else if (sm->method_pending == METHOD_PENDING_CONT) {
			wpa_printf(MSG_DEBUG, "EAP: Method has completed "
				   "pending processing - reprocess pending "
				   "EAP message");
			sm->method_pending = METHOD_PENDING_NONE;
			SM_ENTER(EAP, PROPOSE_METHOD);
		} else