eap_gtc.c

Go to the documentation of this file.

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "common.h"
#include "eap_i.h"
#include "wpa_supplicant.h"
#include "config_ssid.h"


struct eap_gtc_data {
        int prefix;
};


static void * eap_gtc_init(struct eap_sm *sm)
{
        struct eap_gtc_data *data;
        data = malloc(sizeof(*data));
        if (data == NULL)
                return NULL;
        memset(data, 0, sizeof(*data));

        if (sm->m && sm->m->method == EAP_TYPE_FAST) {
                wpa_printf(MSG_DEBUG, "EAP-GTC: EAP-FAST tunnel - use prefix "
                           "with challenge/response");
                data->prefix = 1;
        }
        return data;
}


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


static u8 * eap_gtc_process(struct eap_sm *sm, void *priv,
                            struct eap_method_ret *ret,
                            const u8 *reqData, size_t reqDataLen,
                            size_t *respDataLen)
{
        struct eap_gtc_data *data = priv;
        struct wpa_ssid *config = eap_get_config(sm);
        const struct eap_hdr *req;
        struct eap_hdr *resp;
        const u8 *pos, *password;
        u8 *rpos;
        size_t password_len, len;

        pos = eap_hdr_validate(EAP_TYPE_GTC, reqData, reqDataLen, &len);
        if (pos == NULL) {
                ret->ignore = TRUE;
                return NULL;
        }
        req = (const struct eap_hdr *) reqData;

        wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-GTC: Request message", pos, len);
        if (data->prefix &&
            (len < 10 || memcmp(pos, "CHALLENGE=", 10) != 0)) {
                wpa_printf(MSG_DEBUG, "EAP-GTC: Challenge did not start with "
                           "expected prefix");

                /* Send an empty response in order to allow tunneled
                 * acknowledgement of the failure. This will also cover the
                 * error case which seems to use EAP-MSCHAPv2 like error
                 * reporting with EAP-GTC inside EAP-FAST tunnel. */
                *respDataLen = sizeof(struct eap_hdr) + 1;
                resp = malloc(*respDataLen);
                if (resp == NULL)
                        return NULL;
                resp->code = EAP_CODE_RESPONSE;
                resp->identifier = req->identifier;
                resp->length = host_to_be16(*respDataLen);
                rpos = (u8 *) (resp + 1);
                *rpos++ = EAP_TYPE_GTC;
                return (u8 *) resp;
        }

        if (config == NULL ||
            (config->password == NULL && config->otp == NULL)) {
                wpa_printf(MSG_INFO, "EAP-GTC: Password not configured");
                eap_sm_request_otp(sm, config, (const char *) pos, len);
                ret->ignore = TRUE;
                return NULL;
        }

        if (config->otp) {
                password = config->otp;
                password_len = config->otp_len;
        } else {
                password = config->password;
                password_len = config->password_len;
        }

        ret->ignore = FALSE;

        ret->methodState = data->prefix ? METHOD_MAY_CONT : METHOD_DONE;
        ret->decision = DECISION_COND_SUCC;
        ret->allowNotifications = FALSE;

        *respDataLen = sizeof(struct eap_hdr) + 1 + password_len;
        if (data->prefix) {
                *respDataLen += 9 + config->identity_len + 1;
        }
        resp = malloc(*respDataLen);
        if (resp == NULL)
                return NULL;
        resp->code = EAP_CODE_RESPONSE;
        resp->identifier = req->identifier;
        resp->length = host_to_be16(*respDataLen);
        rpos = (u8 *) (resp + 1);
        *rpos++ = EAP_TYPE_GTC;
        if (data->prefix) {
                memcpy(rpos, "RESPONSE=", 9);
                rpos += 9;
                memcpy(rpos, config->identity, config->identity_len);
                rpos += config->identity_len;
                *rpos++ = '\0';
        }
        memcpy(rpos, password, password_len);
        wpa_hexdump_ascii_key(MSG_MSGDUMP, "EAP-GTC: Response",
                              (u8 *) (resp + 1) + 1,
                              *respDataLen - sizeof(struct eap_hdr) - 1);

        if (config->otp) {
                wpa_printf(MSG_DEBUG, "EAP-GTC: Forgetting used password");
                memset(config->otp, 0, config->otp_len);
                free(config->otp);
                config->otp = NULL;
                config->otp_len = 0;
        }

        return (u8 *) resp;
}


const struct eap_method eap_method_gtc =
{
        .method = EAP_TYPE_GTC,
        .name = "GTC",
        .init = eap_gtc_init,
        .deinit = eap_gtc_deinit,
        .process = eap_gtc_process,
};

---