/*
 * hostapd / EAP-GTC (RFC 3748)
 * Copyright (c) 2004-2006, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "includes.h"

#include "common.h"
#include "eap_i.h"


struct eap_gtc_data {
	enum { CONTINUE, SUCCESS, FAILURE } state;
	int prefix;
};


static void * eap_gtc_init(struct eap_sm *sm)
{
	struct eap_gtc_data *data;

	data = os_zalloc(sizeof(*data));
	if (data == NULL)
		return NULL;
	data->state = CONTINUE;

#ifdef EAP_SERVER_FAST
	if (sm->m && sm->m->vendor == EAP_VENDOR_IETF &&
	    sm->m->method == EAP_TYPE_FAST) {
		wpa_printf(MSG_DEBUG, "EAP-GTC: EAP-FAST tunnel - use prefix "
			   "with challenge/response");
		data->prefix = 1;
	}
#endif /* EAP_SERVER_FAST */

	return data;
}


static void eap_gtc_reset(struct eap_sm *sm, void *priv)
{
	struct eap_gtc_data *data = priv;
	os_free(data);
}


static struct wpabuf * eap_gtc_buildReq(struct eap_sm *sm, void *priv, u8 id)
{
	struct eap_gtc_data *data = priv;
	struct wpabuf *req;
	char *msg;
	size_t msg_len;

	msg = data->prefix ? "CHALLENGE=Password" : "Password";

	msg_len = os_strlen(msg);
	req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_GTC, msg_len,
			    EAP_CODE_REQUEST, id);
	if (req == NULL) {
		wpa_printf(MSG_ERROR, "EAP-GTC: Failed to allocate memory for "
			   "request");
		data->state = FAILURE;
		return NULL;
	}

	wpabuf_put_data(req, msg, msg_len);

	data->state = CONTINUE;

	return req;
}


static bool eap_gtc_check(struct eap_sm *sm, void *priv,
			  struct wpabuf *respData)
{
	const u8 *pos;
	size_t len;

	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_GTC, respData, &len);
	if (pos == NULL || len < 1) {
		wpa_printf(MSG_INFO, "EAP-GTC: Invalid frame");
		return true;
	}

	return false;
}


static void eap_gtc_process(struct eap_sm *sm, void *priv,
			    struct wpabuf *respData)
{
	struct eap_gtc_data *data = priv;
	const u8 *pos;
	size_t rlen;

	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_GTC, respData, &rlen);
	if (pos == NULL || rlen < 1)
		return; /* Should not happen - frame already validated */

	wpa_hexdump_ascii_key(MSG_MSGDUMP, "EAP-GTC: Response", pos, rlen);

#ifdef EAP_SERVER_FAST
	if (data->prefix) {
		const u8 *pos2, *end;
		/* "RESPONSE=<user>\0<password>" */
		if (rlen < 10) {
			wpa_printf(MSG_DEBUG, "EAP-GTC: Too short response "
				   "for EAP-FAST prefix");
			data->state = FAILURE;
			return;
		}

		end = pos + rlen;
		pos += 9;
		pos2 = pos;
		while (pos2 < end && *pos2)
			pos2++;
		if (pos2 == end) {
			wpa_printf(MSG_DEBUG, "EAP-GTC: No password in "
				   "response to EAP-FAST prefix");
			data->state = FAILURE;
			return;
		}

		wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-GTC: Response user",
				  pos, pos2 - pos);
		if (sm->identity && sm->require_identity_match &&
		    (pos2 - pos != (int) sm->identity_len ||
		     os_memcmp(pos, sm->identity, sm->identity_len))) {
			wpa_printf(MSG_DEBUG, "EAP-GTC: Phase 2 Identity did "
				   "not match with required Identity");
			wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-GTC: Expected "
					  "identity",
					  sm->identity, sm->identity_len);
			data->state = FAILURE;
			return;
		} else {
			os_free(sm->identity);
			sm->identity_len = pos2 - pos;
			sm->identity = os_memdup(pos, sm->identity_len);
			if (sm->identity == NULL) {
				data->state = FAILURE;
				return;
			}
		}

		if (eap_user_get(sm, sm->identity, sm->identity_len, 1) != 0) {
			wpa_hexdump_ascii(MSG_DEBUG, "EAP-GTC: Phase2 "
					  "Identity not found in the user "
					  "database",
					  sm->identity, sm->identity_len);
			data->state = FAILURE;
			return;
		}

		pos = pos2 + 1;
		rlen = end - pos;
		wpa_hexdump_ascii_key(MSG_MSGDUMP,
				      "EAP-GTC: Response password",
				      pos, rlen);
	}
#endif /* EAP_SERVER_FAST */

	if (sm->user == NULL || sm->user->password == NULL ||
	    sm->user->password_hash) {
		wpa_printf(MSG_INFO, "EAP-GTC: Plaintext password not "
			   "configured");
		data->state = FAILURE;
		return;
	}

	if (rlen != sm->user->password_len ||
	    os_memcmp_const(pos, sm->user->password, rlen) != 0) {
		wpa_printf(MSG_DEBUG, "EAP-GTC: Done - Failure");
		data->state = FAILURE;
	} else {
		wpa_printf(MSG_DEBUG, "EAP-GTC: Done - Success");
		data->state = SUCCESS;
	}
}


static bool eap_gtc_isDone(struct eap_sm *sm, void *priv)
{
	struct eap_gtc_data *data = priv;
	return data->state != CONTINUE;
}


static bool eap_gtc_isSuccess(struct eap_sm *sm, void *priv)
{
	struct eap_gtc_data *data = priv;
	return data->state == SUCCESS;
}


int eap_server_gtc_register(void)
{
	struct eap_method *eap;

	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
				      EAP_VENDOR_IETF, EAP_TYPE_GTC, "GTC");
	if (eap == NULL)
		return -1;

	eap->init = eap_gtc_init;
	eap->reset = eap_gtc_reset;
	eap->buildReq = eap_gtc_buildReq;
	eap->check = eap_gtc_check;
	eap->process = eap_gtc_process;
	eap->isDone = eap_gtc_isDone;
	eap->isSuccess = eap_gtc_isSuccess;

	return eap_server_method_register(eap);
}