eap_gpsk.c

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/*
 * EAP peer method: EAP-GPSK (RFC 5433)
 * Copyright (c) 2006-2008, Jouni Malinen <j@w1.fi>
 *
 * 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 "common.h"
#include "eap_peer/eap_i.h"
#include "eap_common/eap_gpsk_common.h"

struct eap_gpsk_data {
        enum { GPSK_1, GPSK_3, SUCCESS, FAILURE } state;
        u8 rand_server[EAP_GPSK_RAND_LEN];
        u8 rand_peer[EAP_GPSK_RAND_LEN];
        u8 msk[EAP_MSK_LEN];
        u8 emsk[EAP_EMSK_LEN];
        u8 sk[EAP_GPSK_MAX_SK_LEN];
        size_t sk_len;
        u8 pk[EAP_GPSK_MAX_PK_LEN];
        size_t pk_len;
        u8 session_id;
        int session_id_set;
        u8 *id_peer;
        size_t id_peer_len;
        u8 *id_server;
        size_t id_server_len;
        int vendor; /* CSuite/Specifier */
        int specifier; /* CSuite/Specifier */
        u8 *psk;
        size_t psk_len;
};


static struct wpabuf * eap_gpsk_send_gpsk_2(struct eap_gpsk_data *data,
                                            u8 identifier,
                                            const u8 *csuite_list,
                                            size_t csuite_list_len);
static struct wpabuf * eap_gpsk_send_gpsk_4(struct eap_gpsk_data *data,
                                            u8 identifier);


#ifndef CONFIG_NO_STDOUT_DEBUG
static const char * eap_gpsk_state_txt(int state)
{
        switch (state) {
        case GPSK_1:
                return "GPSK-1";
        case GPSK_3:
                return "GPSK-3";
        case SUCCESS:
                return "SUCCESS";
        case FAILURE:
                return "FAILURE";
        default:
                return "?";
        }
}
#endif /* CONFIG_NO_STDOUT_DEBUG */


static void eap_gpsk_state(struct eap_gpsk_data *data, int state)
{
        wpa_printf(MSG_DEBUG, "EAP-GPSK: %s -> %s",
                   eap_gpsk_state_txt(data->state),
                   eap_gpsk_state_txt(state));
        data->state = state;
}


static void eap_gpsk_deinit(struct eap_sm *sm, void *priv);


static void * eap_gpsk_init(struct eap_sm *sm)
{
        struct eap_gpsk_data *data;
        const u8 *identity, *password;
        size_t identity_len, password_len;

        password = eap_get_config_password(sm, &password_len);
        if (password == NULL) {
                wpa_printf(MSG_INFO, "EAP-GPSK: No key (password) configured");
                return NULL;
        }

        data = os_zalloc(sizeof(*data));
        if (data == NULL)
                return NULL;
        data->state = GPSK_1;

        identity = eap_get_config_identity(sm, &identity_len);
        if (identity) {
                data->id_peer = os_malloc(identity_len);
                if (data->id_peer == NULL) {
                        eap_gpsk_deinit(sm, data);
                        return NULL;
                }
                os_memcpy(data->id_peer, identity, identity_len);
                data->id_peer_len = identity_len;
        }

        data->psk = os_malloc(password_len);
        if (data->psk == NULL) {
                eap_gpsk_deinit(sm, data);
                return NULL;
        }
        os_memcpy(data->psk, password, password_len);
        data->psk_len = password_len;

        return data;
}


static void eap_gpsk_deinit(struct eap_sm *sm, void *priv)
{
        struct eap_gpsk_data *data = priv;
        os_free(data->id_server);
        os_free(data->id_peer);
        os_free(data->psk);
        os_free(data);
}


static const u8 * eap_gpsk_process_id_server(struct eap_gpsk_data *data,
                                             const u8 *pos, const u8 *end)
{
        u16 alen;

        if (end - pos < 2) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Too short GPSK-1 packet");
                return NULL;
        }
        alen = WPA_GET_BE16(pos);
        pos += 2;
        if (end - pos < alen) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: ID_Server overflow");
                return NULL;
        }
        os_free(data->id_server);
        data->id_server = os_malloc(alen);
        if (data->id_server == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: No memory for ID_Server");
                return NULL;
        }
        os_memcpy(data->id_server, pos, alen);
        data->id_server_len = alen;
        wpa_hexdump_ascii(MSG_DEBUG, "EAP-GPSK: ID_Server",
                          data->id_server, data->id_server_len);
        pos += alen;

        return pos;
}


static const u8 * eap_gpsk_process_rand_server(struct eap_gpsk_data *data,
                                               const u8 *pos, const u8 *end)
{
        if (pos == NULL)
                return NULL;

        if (end - pos < EAP_GPSK_RAND_LEN) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: RAND_Server overflow");
                return NULL;
        }
        os_memcpy(data->rand_server, pos, EAP_GPSK_RAND_LEN);
        wpa_hexdump(MSG_DEBUG, "EAP-GPSK: RAND_Server",
                    data->rand_server, EAP_GPSK_RAND_LEN);
        pos += EAP_GPSK_RAND_LEN;

        return pos;
}


static int eap_gpsk_select_csuite(struct eap_sm *sm,
                                  struct eap_gpsk_data *data,
                                  const u8 *csuite_list,
                                  size_t csuite_list_len)
{
        struct eap_gpsk_csuite *csuite;
        int i, count;

        count = csuite_list_len / sizeof(struct eap_gpsk_csuite);
        data->vendor = EAP_GPSK_VENDOR_IETF;
        data->specifier = EAP_GPSK_CIPHER_RESERVED;
        csuite = (struct eap_gpsk_csuite *) csuite_list;
        for (i = 0; i < count; i++) {
                int vendor, specifier;
                vendor = WPA_GET_BE32(csuite->vendor);
                specifier = WPA_GET_BE16(csuite->specifier);
                wpa_printf(MSG_DEBUG, "EAP-GPSK: CSuite[%d]: %d:%d",
                           i, vendor, specifier);
                if (data->vendor == EAP_GPSK_VENDOR_IETF &&
                    data->specifier == EAP_GPSK_CIPHER_RESERVED &&
                    eap_gpsk_supported_ciphersuite(vendor, specifier)) {
                        data->vendor = vendor;
                        data->specifier = specifier;
                }
                csuite++;
        }
        if (data->vendor == EAP_GPSK_VENDOR_IETF &&
            data->specifier == EAP_GPSK_CIPHER_RESERVED) {
                wpa_msg(sm->msg_ctx, MSG_INFO, "EAP-GPSK: No supported "
                        "ciphersuite found");
                return -1;
        }
        wpa_printf(MSG_DEBUG, "EAP-GPSK: Selected ciphersuite %d:%d",
                   data->vendor, data->specifier);

        return 0;
}


static const u8 * eap_gpsk_process_csuite_list(struct eap_sm *sm,
                                               struct eap_gpsk_data *data,
                                               const u8 **list,
                                               size_t *list_len,
                                               const u8 *pos, const u8 *end)
{
        if (pos == NULL)
                return NULL;

        if (end - pos < 2) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Too short GPSK-1 packet");
                return NULL;
        }
        *list_len = WPA_GET_BE16(pos);
        pos += 2;
        if (end - pos < (int) *list_len) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: CSuite_List overflow");
                return NULL;
        }
        if (*list_len == 0 || (*list_len % sizeof(struct eap_gpsk_csuite))) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Invalid CSuite_List len %lu",
                           (unsigned long) *list_len);
                return NULL;
        }
        *list = pos;
        pos += *list_len;

        if (eap_gpsk_select_csuite(sm, data, *list, *list_len) < 0)
                return NULL;

        return pos;
}


static struct wpabuf * eap_gpsk_process_gpsk_1(struct eap_sm *sm,
                                               struct eap_gpsk_data *data,
                                               struct eap_method_ret *ret,
                                               const struct wpabuf *reqData,
                                               const u8 *payload,
                                               size_t payload_len)
{
        size_t csuite_list_len;
        const u8 *csuite_list, *pos, *end;
        struct wpabuf *resp;

        if (data->state != GPSK_1) {
                ret->ignore = TRUE;
                return NULL;
        }

        wpa_printf(MSG_DEBUG, "EAP-GPSK: Received Request/GPSK-1");

        end = payload + payload_len;

        pos = eap_gpsk_process_id_server(data, payload, end);
        pos = eap_gpsk_process_rand_server(data, pos, end);
        pos = eap_gpsk_process_csuite_list(sm, data, &csuite_list,
                                           &csuite_list_len, pos, end);
        if (pos == NULL) {
                eap_gpsk_state(data, FAILURE);
                return NULL;
        }

        resp = eap_gpsk_send_gpsk_2(data, eap_get_id(reqData),
                                    csuite_list, csuite_list_len);
        if (resp == NULL)
                return NULL;

        eap_gpsk_state(data, GPSK_3);

        return resp;
}


static struct wpabuf * eap_gpsk_send_gpsk_2(struct eap_gpsk_data *data,
                                            u8 identifier,
                                            const u8 *csuite_list,
                                            size_t csuite_list_len)
{
        struct wpabuf *resp;
        size_t len, miclen;
        u8 *rpos, *start;
        struct eap_gpsk_csuite *csuite;

        wpa_printf(MSG_DEBUG, "EAP-GPSK: Sending Response/GPSK-2");

        miclen = eap_gpsk_mic_len(data->vendor, data->specifier);
        len = 1 + 2 + data->id_peer_len + 2 + data->id_server_len +
                2 * EAP_GPSK_RAND_LEN + 2 + csuite_list_len +
                sizeof(struct eap_gpsk_csuite) + 2 + miclen;

        resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_GPSK, len,
                             EAP_CODE_RESPONSE, identifier);
        if (resp == NULL)
                return NULL;

        wpabuf_put_u8(resp, EAP_GPSK_OPCODE_GPSK_2);
        start = wpabuf_put(resp, 0);

        wpa_hexdump_ascii(MSG_DEBUG, "EAP-GPSK: ID_Peer",
                          data->id_peer, data->id_peer_len);
        wpabuf_put_be16(resp, data->id_peer_len);
        wpabuf_put_data(resp, data->id_peer, data->id_peer_len);

        wpabuf_put_be16(resp, data->id_server_len);
        wpabuf_put_data(resp, data->id_server, data->id_server_len);

        if (os_get_random(data->rand_peer, EAP_GPSK_RAND_LEN)) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Failed to get random data "
                           "for RAND_Peer");
                eap_gpsk_state(data, FAILURE);
                wpabuf_free(resp);
                return NULL;
        }
        wpa_hexdump(MSG_DEBUG, "EAP-GPSK: RAND_Peer",
                    data->rand_peer, EAP_GPSK_RAND_LEN);
        wpabuf_put_data(resp, data->rand_peer, EAP_GPSK_RAND_LEN);
        wpabuf_put_data(resp, data->rand_server, EAP_GPSK_RAND_LEN);

        wpabuf_put_be16(resp, csuite_list_len);
        wpabuf_put_data(resp, csuite_list, csuite_list_len);

        csuite = wpabuf_put(resp, sizeof(*csuite));
        WPA_PUT_BE32(csuite->vendor, data->vendor);
        WPA_PUT_BE16(csuite->specifier, data->specifier);

        if (eap_gpsk_derive_keys(data->psk, data->psk_len,
                                 data->vendor, data->specifier,
                                 data->rand_peer, data->rand_server,
                                 data->id_peer, data->id_peer_len,
                                 data->id_server, data->id_server_len,
                                 data->msk, data->emsk,
                                 data->sk, &data->sk_len,
                                 data->pk, &data->pk_len) < 0) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Failed to derive keys");
                eap_gpsk_state(data, FAILURE);
                wpabuf_free(resp);
                return NULL;
        }

        /* No PD_Payload_1 */
        wpabuf_put_be16(resp, 0);

        rpos = wpabuf_put(resp, miclen);
        if (eap_gpsk_compute_mic(data->sk, data->sk_len, data->vendor,
                                 data->specifier, start, rpos - start, rpos) <
            0) {
                eap_gpsk_state(data, FAILURE);
                wpabuf_free(resp);
                return NULL;
        }

        return resp;
}


static const u8 * eap_gpsk_validate_rand(struct eap_gpsk_data *data,
                                         const u8 *pos, const u8 *end)
{
        if (end - pos < EAP_GPSK_RAND_LEN) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Message too short for "
                           "RAND_Peer");
                return NULL;
        }
        if (os_memcmp(pos, data->rand_peer, EAP_GPSK_RAND_LEN) != 0) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: RAND_Peer in GPSK-2 and "
                           "GPSK-3 did not match");
                wpa_hexdump(MSG_DEBUG, "EAP-GPSK: RAND_Peer in GPSK-2",
                            data->rand_peer, EAP_GPSK_RAND_LEN);
                wpa_hexdump(MSG_DEBUG, "EAP-GPSK: RAND_Peer in GPSK-3",
                            pos, EAP_GPSK_RAND_LEN);
                return NULL;
        }
        pos += EAP_GPSK_RAND_LEN;

        if (end - pos < EAP_GPSK_RAND_LEN) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Message too short for "
                           "RAND_Server");
                return NULL;
        }
        if (os_memcmp(pos, data->rand_server, EAP_GPSK_RAND_LEN) != 0) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: RAND_Server in GPSK-1 and "
                           "GPSK-3 did not match");
                wpa_hexdump(MSG_DEBUG, "EAP-GPSK: RAND_Server in GPSK-1",
                            data->rand_server, EAP_GPSK_RAND_LEN);
                wpa_hexdump(MSG_DEBUG, "EAP-GPSK: RAND_Server in GPSK-3",
                            pos, EAP_GPSK_RAND_LEN);
                return NULL;
        }
        pos += EAP_GPSK_RAND_LEN;

        return pos;
}


static const u8 * eap_gpsk_validate_id_server(struct eap_gpsk_data *data,
                                              const u8 *pos, const u8 *end)
{
        size_t len;

        if (pos == NULL)
                return NULL;

        if (end - pos < (int) 2) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Message too short for "
                           "length(ID_Server)");
                return NULL;
        }

        len = WPA_GET_BE16(pos);
        pos += 2;

        if (end - pos < (int) len) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Message too short for "
                           "ID_Server");
                return NULL;
        }

        if (len != data->id_server_len ||
            os_memcmp(pos, data->id_server, len) != 0) {
                wpa_printf(MSG_INFO, "EAP-GPSK: ID_Server did not match with "
                           "the one used in GPSK-1");
                wpa_hexdump_ascii(MSG_DEBUG, "EAP-GPSK: ID_Server in GPSK-1",
                                  data->id_server, data->id_server_len);
                wpa_hexdump_ascii(MSG_DEBUG, "EAP-GPSK: ID_Server in GPSK-3",
                                  pos, len);
                return NULL;
        }

        pos += len;

        return pos;
}


static const u8 * eap_gpsk_validate_csuite(struct eap_gpsk_data *data,
                                           const u8 *pos, const u8 *end)
{
        int vendor, specifier;
        const struct eap_gpsk_csuite *csuite;

        if (pos == NULL)
                return NULL;

        if (end - pos < (int) sizeof(*csuite)) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Message too short for "
                           "CSuite_Sel");
                return NULL;
        }
        csuite = (const struct eap_gpsk_csuite *) pos;
        vendor = WPA_GET_BE32(csuite->vendor);
        specifier = WPA_GET_BE16(csuite->specifier);
        pos += sizeof(*csuite);
        if (vendor != data->vendor || specifier != data->specifier) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: CSuite_Sel (%d:%d) does not "
                           "match with the one sent in GPSK-2 (%d:%d)",
                           vendor, specifier, data->vendor, data->specifier);
                return NULL;
        }

        return pos;
}


static const u8 * eap_gpsk_validate_pd_payload_2(struct eap_gpsk_data *data,
                                                 const u8 *pos, const u8 *end)
{
        u16 alen;

        if (pos == NULL)
                return NULL;

        if (end - pos < 2) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Message too short for "
                           "PD_Payload_2 length");
                return NULL;
        }
        alen = WPA_GET_BE16(pos);
        pos += 2;
        if (end - pos < alen) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Message too short for "
                           "%d-octet PD_Payload_2", alen);
                return NULL;
        }
        wpa_hexdump(MSG_DEBUG, "EAP-GPSK: PD_Payload_2", pos, alen);
        pos += alen;

        return pos;
}


static const u8 * eap_gpsk_validate_gpsk_3_mic(struct eap_gpsk_data *data,
                                               const u8 *payload,
                                               const u8 *pos, const u8 *end)
{
        size_t miclen;
        u8 mic[EAP_GPSK_MAX_MIC_LEN];

        if (pos == NULL)
                return NULL;

        miclen = eap_gpsk_mic_len(data->vendor, data->specifier);
        if (end - pos < (int) miclen) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Message too short for MIC "
                           "(left=%lu miclen=%lu)",
                           (unsigned long) (end - pos),
                           (unsigned long) miclen);
                return NULL;
        }
        if (eap_gpsk_compute_mic(data->sk, data->sk_len, data->vendor,
                                 data->specifier, payload, pos - payload, mic)
            < 0) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Failed to compute MIC");
                return NULL;
        }
        if (os_memcmp(mic, pos, miclen) != 0) {
                wpa_printf(MSG_INFO, "EAP-GPSK: Incorrect MIC in GPSK-3");
                wpa_hexdump(MSG_DEBUG, "EAP-GPSK: Received MIC", pos, miclen);
                wpa_hexdump(MSG_DEBUG, "EAP-GPSK: Computed MIC", mic, miclen);
                return NULL;
        }
        pos += miclen;

        return pos;
}


static struct wpabuf * eap_gpsk_process_gpsk_3(struct eap_sm *sm,
                                               struct eap_gpsk_data *data,
                                               struct eap_method_ret *ret,
                                               const struct wpabuf *reqData,
                                               const u8 *payload,
                                               size_t payload_len)
{
        struct wpabuf *resp;
        const u8 *pos, *end;

        if (data->state != GPSK_3) {
                ret->ignore = TRUE;
                return NULL;
        }

        wpa_printf(MSG_DEBUG, "EAP-GPSK: Received Request/GPSK-3");

        end = payload + payload_len;

        pos = eap_gpsk_validate_rand(data, payload, end);
        pos = eap_gpsk_validate_id_server(data, pos, end);
        pos = eap_gpsk_validate_csuite(data, pos, end);
        pos = eap_gpsk_validate_pd_payload_2(data, pos, end);
        pos = eap_gpsk_validate_gpsk_3_mic(data, payload, pos, end);

        if (pos == NULL) {
                eap_gpsk_state(data, FAILURE);
                return NULL;
        }
        if (pos != end) {
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Ignored %lu bytes of extra "
                           "data in the end of GPSK-2",
                           (unsigned long) (end - pos));
        }

        resp = eap_gpsk_send_gpsk_4(data, eap_get_id(reqData));
        if (resp == NULL)
                return NULL;

        eap_gpsk_state(data, SUCCESS);
        ret->methodState = METHOD_DONE;
        ret->decision = DECISION_UNCOND_SUCC;

        return resp;
}


static struct wpabuf * eap_gpsk_send_gpsk_4(struct eap_gpsk_data *data,
                                            u8 identifier)
{
        struct wpabuf *resp;
        u8 *rpos, *start;
        size_t mlen;

        wpa_printf(MSG_DEBUG, "EAP-GPSK: Sending Response/GPSK-4");

        mlen = eap_gpsk_mic_len(data->vendor, data->specifier);

        resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_GPSK, 1 + 2 + mlen,
                             EAP_CODE_RESPONSE, identifier);
        if (resp == NULL)
                return NULL;

        wpabuf_put_u8(resp, EAP_GPSK_OPCODE_GPSK_4);
        start = wpabuf_put(resp, 0);

        /* No PD_Payload_3 */
        wpabuf_put_be16(resp, 0);

        rpos = wpabuf_put(resp, mlen);
        if (eap_gpsk_compute_mic(data->sk, data->sk_len, data->vendor,
                                 data->specifier, start, rpos - start, rpos) <
            0) {
                eap_gpsk_state(data, FAILURE);
                wpabuf_free(resp);
                return NULL;
        }

        return resp;
}


static struct wpabuf * eap_gpsk_process(struct eap_sm *sm, void *priv,
                                        struct eap_method_ret *ret,
                                        const struct wpabuf *reqData)
{
        struct eap_gpsk_data *data = priv;
        struct wpabuf *resp;
        const u8 *pos;
        size_t len;

        pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_GPSK, reqData, &len);
        if (pos == NULL || len < 1) {
                ret->ignore = TRUE;
                return NULL;
        }

        wpa_printf(MSG_DEBUG, "EAP-GPSK: Received frame: opcode %d", *pos);

        ret->ignore = FALSE;
        ret->methodState = METHOD_MAY_CONT;
        ret->decision = DECISION_FAIL;
        ret->allowNotifications = FALSE;

        switch (*pos) {
        case EAP_GPSK_OPCODE_GPSK_1:
                resp = eap_gpsk_process_gpsk_1(sm, data, ret, reqData,
                                               pos + 1, len - 1);
                break;
        case EAP_GPSK_OPCODE_GPSK_3:
                resp = eap_gpsk_process_gpsk_3(sm, data, ret, reqData,
                                               pos + 1, len - 1);
                break;
        default:
                wpa_printf(MSG_DEBUG, "EAP-GPSK: Ignoring message with "
                           "unknown opcode %d", *pos);
                ret->ignore = TRUE;
                return NULL;
        }

        return resp;
}


static Boolean eap_gpsk_isKeyAvailable(struct eap_sm *sm, void *priv)
{
        struct eap_gpsk_data *data = priv;
        return data->state == SUCCESS;
}


static u8 * eap_gpsk_getKey(struct eap_sm *sm, void *priv, size_t *len)
{
        struct eap_gpsk_data *data = priv;
        u8 *key;

        if (data->state != SUCCESS)
                return NULL;

        key = os_malloc(EAP_MSK_LEN);
        if (key == NULL)
                return NULL;
        os_memcpy(key, data->msk, EAP_MSK_LEN);
        *len = EAP_MSK_LEN;

        return key;
}


static u8 * eap_gpsk_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
{
        struct eap_gpsk_data *data = priv;
        u8 *key;

        if (data->state != SUCCESS)
                return NULL;

        key = os_malloc(EAP_EMSK_LEN);
        if (key == NULL)
                return NULL;
        os_memcpy(key, data->emsk, EAP_EMSK_LEN);
        *len = EAP_EMSK_LEN;

        return key;
}


int eap_peer_gpsk_register(void)
{
        struct eap_method *eap;
        int ret;

        eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
                                    EAP_VENDOR_IETF, EAP_TYPE_GPSK, "GPSK");
        if (eap == NULL)
                return -1;

        eap->init = eap_gpsk_init;
        eap->deinit = eap_gpsk_deinit;
        eap->process = eap_gpsk_process;
        eap->isKeyAvailable = eap_gpsk_isKeyAvailable;
        eap->getKey = eap_gpsk_getKey;
        eap->get_emsk = eap_gpsk_get_emsk;

        ret = eap_peer_method_register(eap);
        if (ret)
                eap_peer_method_free(eap);
        return ret;
}