eap_tls.c

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/*
 * EAP peer method: EAP-TLS (RFC 2716)
 * Copyright (c) 2004-2008, 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 "crypto/tls.h"
#include "eap_i.h"
#include "eap_tls_common.h"
#include "eap_config.h"


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


struct eap_tls_data {
        struct eap_ssl_data ssl;
        u8 *key_data;
};


static void * eap_tls_init(struct eap_sm *sm)
{
        struct eap_tls_data *data;
        struct eap_peer_config *config = eap_get_config(sm);
        if (config == NULL ||
            ((sm->init_phase2 ? config->private_key2 : config->private_key)
             == NULL &&
             (sm->init_phase2 ? config->engine2 : config->engine) == 0)) {
                wpa_printf(MSG_INFO, "EAP-TLS: Private key not configured");
                return NULL;
        }

        data = os_zalloc(sizeof(*data));
        if (data == NULL)
                return NULL;

        if (eap_peer_tls_ssl_init(sm, &data->ssl, config)) {
                wpa_printf(MSG_INFO, "EAP-TLS: Failed to initialize SSL.");
                eap_tls_deinit(sm, data);
                if (config->engine) {
                        wpa_printf(MSG_DEBUG, "EAP-TLS: Requesting Smartcard "
                                   "PIN");
                        eap_sm_request_pin(sm);
                        sm->ignore = TRUE;
                } else if (config->private_key && !config->private_key_passwd)
                {
                        wpa_printf(MSG_DEBUG, "EAP-TLS: Requesting private "
                                   "key passphrase");
                        eap_sm_request_passphrase(sm);
                        sm->ignore = TRUE;
                }
                return NULL;
        }

        return data;
}


static void eap_tls_deinit(struct eap_sm *sm, void *priv)
{
        struct eap_tls_data *data = priv;
        if (data == NULL)
                return;
        eap_peer_tls_ssl_deinit(sm, &data->ssl);
        os_free(data->key_data);
        os_free(data);
}


static struct wpabuf * eap_tls_failure(struct eap_sm *sm,
                                       struct eap_tls_data *data,
                                       struct eap_method_ret *ret, int res,
                                       struct wpabuf *resp, u8 id)
{
        wpa_printf(MSG_DEBUG, "EAP-TLS: TLS processing failed");

        ret->methodState = METHOD_DONE;
        ret->decision = DECISION_FAIL;

        if (res == -1) {
                struct eap_peer_config *config = eap_get_config(sm);
                if (config) {
                        /*
                         * The TLS handshake failed. So better forget the old
                         * PIN. It may be wrong, we cannot be sure but trying
                         * the wrong one again might block it on the card--so
                         * better ask the user again.
                         */
                        os_free(config->pin);
                        config->pin = NULL;
                }
        }

        if (resp) {
                /*
                 * This is likely an alert message, so send it instead of just
                 * ACKing the error.
                 */
                return resp;
        }

        return eap_peer_tls_build_ack(id, EAP_TYPE_TLS, 0);
}


static void eap_tls_success(struct eap_sm *sm, struct eap_tls_data *data,
                            struct eap_method_ret *ret)
{
        wpa_printf(MSG_DEBUG, "EAP-TLS: Done");

        ret->methodState = METHOD_DONE;
        ret->decision = DECISION_UNCOND_SUCC;

        os_free(data->key_data);
        data->key_data = eap_peer_tls_derive_key(sm, &data->ssl,
                                                 "client EAP encryption",
                                                 EAP_TLS_KEY_LEN +
                                                 EAP_EMSK_LEN);
        if (data->key_data) {
                wpa_hexdump_key(MSG_DEBUG, "EAP-TLS: Derived key",
                                data->key_data, EAP_TLS_KEY_LEN);
                wpa_hexdump_key(MSG_DEBUG, "EAP-TLS: Derived EMSK",
                                data->key_data + EAP_TLS_KEY_LEN,
                                EAP_EMSK_LEN);
        } else {
                wpa_printf(MSG_INFO, "EAP-TLS: Failed to derive key");
        }
}


static struct wpabuf * eap_tls_process(struct eap_sm *sm, void *priv,
                                       struct eap_method_ret *ret,
                                       const struct wpabuf *reqData)
{
        size_t left;
        int res;
        struct wpabuf *resp;
        u8 flags, id;
        const u8 *pos;
        struct eap_tls_data *data = priv;

        pos = eap_peer_tls_process_init(sm, &data->ssl, EAP_TYPE_TLS, ret,
                                        reqData, &left, &flags);
        if (pos == NULL)
                return NULL;
        id = eap_get_id(reqData);

        if (flags & EAP_TLS_FLAGS_START) {
                wpa_printf(MSG_DEBUG, "EAP-TLS: Start");
                left = 0; /* make sure that this frame is empty, even though it
                           * should always be, anyway */
        }

        resp = NULL;
        res = eap_peer_tls_process_helper(sm, &data->ssl, EAP_TYPE_TLS, 0, id,
                                          pos, left, &resp);

        if (res < 0) {
                return eap_tls_failure(sm, data, ret, res, resp, id);
        }

        if (tls_connection_established(sm->ssl_ctx, data->ssl.conn))
                eap_tls_success(sm, data, ret);

        if (res == 1) {
                wpabuf_free(resp);
                return eap_peer_tls_build_ack(id, EAP_TYPE_TLS, 0);
        }

        return resp;
}


static Boolean eap_tls_has_reauth_data(struct eap_sm *sm, void *priv)
{
        struct eap_tls_data *data = priv;
        return tls_connection_established(sm->ssl_ctx, data->ssl.conn);
}


static void eap_tls_deinit_for_reauth(struct eap_sm *sm, void *priv)
{
}


static void * eap_tls_init_for_reauth(struct eap_sm *sm, void *priv)
{
        struct eap_tls_data *data = priv;
        os_free(data->key_data);
        data->key_data = NULL;
        if (eap_peer_tls_reauth_init(sm, &data->ssl)) {
                os_free(data);
                return NULL;
        }
        return priv;
}


static int eap_tls_get_status(struct eap_sm *sm, void *priv, char *buf,
                              size_t buflen, int verbose)
{
        struct eap_tls_data *data = priv;
        return eap_peer_tls_status(sm, &data->ssl, buf, buflen, verbose);
}


static Boolean eap_tls_isKeyAvailable(struct eap_sm *sm, void *priv)
{
        struct eap_tls_data *data = priv;
        return data->key_data != NULL;
}


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

        if (data->key_data == NULL)
                return NULL;

        key = os_malloc(EAP_TLS_KEY_LEN);
        if (key == NULL)
                return NULL;

        *len = EAP_TLS_KEY_LEN;
        os_memcpy(key, data->key_data, EAP_TLS_KEY_LEN);

        return key;
}


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

        if (data->key_data == NULL)
                return NULL;

        key = os_malloc(EAP_EMSK_LEN);
        if (key == NULL)
                return NULL;

        *len = EAP_EMSK_LEN;
        os_memcpy(key, data->key_data + EAP_TLS_KEY_LEN, EAP_EMSK_LEN);

        return key;
}


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

        eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
                                    EAP_VENDOR_IETF, EAP_TYPE_TLS, "TLS");
        if (eap == NULL)
                return -1;

        eap->init = eap_tls_init;
        eap->deinit = eap_tls_deinit;
        eap->process = eap_tls_process;
        eap->isKeyAvailable = eap_tls_isKeyAvailable;
        eap->getKey = eap_tls_getKey;
        eap->get_status = eap_tls_get_status;
        eap->has_reauth_data = eap_tls_has_reauth_data;
        eap->deinit_for_reauth = eap_tls_deinit_for_reauth;
        eap->init_for_reauth = eap_tls_init_for_reauth;
        eap->get_emsk = eap_tls_get_emsk;

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