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432 lines
10 KiB
C
432 lines
10 KiB
C
/*
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* hostapd / EAP-SIM (draft-haverinen-pppext-eap-sim-15.txt)
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* Copyright (c) 2005, Jouni Malinen <jkmaline@cc.hut.fi>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Alternatively, this software may be distributed under the terms of BSD
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* license.
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*
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* See README and COPYING for more details.
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <netinet/in.h>
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#include "hostapd.h"
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#include "common.h"
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#include "crypto.h"
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#include "eap_i.h"
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#include "eap_sim_common.h"
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#include "eap_sim_db.h"
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#define EAP_SIM_VERSION 1
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/* EAP-SIM Subtypes */
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#define EAP_SIM_SUBTYPE_START 10
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#define EAP_SIM_SUBTYPE_CHALLENGE 11
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#define EAP_SIM_SUBTYPE_NOTIFICATION 12
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#define EAP_SIM_SUBTYPE_REAUTHENTICATION 13
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#define EAP_SIM_SUBTYPE_CLIENT_ERROR 14
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/* AT_CLIENT_ERROR_CODE error codes */
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#define EAP_SIM_UNABLE_TO_PROCESS_PACKET 0
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#define EAP_SIM_UNSUPPORTED_VERSION 1
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#define EAP_SIM_INSUFFICIENT_NUM_OF_CHAL 2
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#define EAP_SIM_RAND_NOT_FRESH 3
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#define KC_LEN 8
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#define SRES_LEN 4
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#define EAP_SIM_MAX_FAST_REAUTHS 1000
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#define EAP_SIM_MAX_CHAL 3
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struct eap_sim_data {
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u8 mk[EAP_SIM_MK_LEN];
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u8 nonce_mt[EAP_SIM_NONCE_MT_LEN];
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u8 k_aut[EAP_SIM_K_AUT_LEN];
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u8 k_encr[EAP_SIM_K_ENCR_LEN];
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u8 msk[EAP_SIM_KEYING_DATA_LEN];
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u8 kc[EAP_SIM_MAX_CHAL][KC_LEN];
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u8 sres[EAP_SIM_MAX_CHAL][SRES_LEN];
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u8 rand[EAP_SIM_MAX_CHAL][GSM_RAND_LEN];
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int num_chal;
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enum { START, CHALLENGE, SUCCESS, FAILURE } state;
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};
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static const char * eap_sim_state_txt(int state)
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{
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switch (state) {
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case START:
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return "START";
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case CHALLENGE:
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return "CHALLENGE";
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case SUCCESS:
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return "SUCCESS";
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case FAILURE:
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return "FAILURE";
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default:
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return "Unknown?!";
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}
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}
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static void eap_sim_state(struct eap_sim_data *data, int state)
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{
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wpa_printf(MSG_DEBUG, "EAP-SIM %s -> %s",
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eap_sim_state_txt(data->state),
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eap_sim_state_txt(state));
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data->state = state;
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}
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static void * eap_sim_init(struct eap_sm *sm)
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{
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struct eap_sim_data *data;
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if (sm->eap_sim_db_priv == NULL) {
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wpa_printf(MSG_WARNING, "EAP-SIM: eap_sim_db not configured");
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return NULL;
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}
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data = malloc(sizeof(*data));
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if (data == NULL)
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return data;
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memset(data, 0, sizeof(*data));
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data->state = START;
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return data;
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}
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static void eap_sim_reset(struct eap_sm *sm, void *priv)
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{
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struct eap_sim_data *data = priv;
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free(data);
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}
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static u8 * eap_sim_build_start(struct eap_sm *sm, struct eap_sim_data *data,
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int id, size_t *reqDataLen)
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{
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struct eap_sim_msg *msg;
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u8 ver[2];
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msg = eap_sim_msg_init(EAP_CODE_REQUEST, id, EAP_TYPE_SIM,
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EAP_SIM_SUBTYPE_START);
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if (eap_sim_db_identity_known(sm->eap_sim_db_priv, sm->identity,
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sm->identity_len)) {
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eap_sim_msg_add(msg, EAP_SIM_AT_PERMANENT_ID_REQ, 0, NULL, 0);
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}
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ver[0] = 0;
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ver[1] = EAP_SIM_VERSION;
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eap_sim_msg_add(msg, EAP_SIM_AT_VERSION_LIST, sizeof(ver),
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ver, sizeof(ver));
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return eap_sim_msg_finish(msg, reqDataLen, NULL, NULL, 0);
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}
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static u8 * eap_sim_build_challenge(struct eap_sm *sm,
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struct eap_sim_data *data,
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int id, size_t *reqDataLen)
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{
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struct eap_sim_msg *msg;
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msg = eap_sim_msg_init(EAP_CODE_REQUEST, id, EAP_TYPE_SIM,
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EAP_SIM_SUBTYPE_CHALLENGE);
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eap_sim_msg_add(msg, EAP_SIM_AT_RAND, 0, (u8 *) data->rand,
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data->num_chal * GSM_RAND_LEN);
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eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
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return eap_sim_msg_finish(msg, reqDataLen, data->k_aut, data->nonce_mt,
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EAP_SIM_NONCE_MT_LEN);
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}
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static u8 * eap_sim_buildReq(struct eap_sm *sm, void *priv, int id,
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size_t *reqDataLen)
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{
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struct eap_sim_data *data = priv;
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switch (data->state) {
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case START:
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return eap_sim_build_start(sm, data, id, reqDataLen);
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case CHALLENGE:
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return eap_sim_build_challenge(sm, data, id, reqDataLen);
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default:
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wpa_printf(MSG_DEBUG, "EAP-SIM: Unknown state %d in "
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"buildReq", data->state);
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break;
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}
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return NULL;
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}
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static Boolean eap_sim_check(struct eap_sm *sm, void *priv,
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u8 *respData, size_t respDataLen)
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{
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struct eap_sim_data *data = priv;
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struct eap_hdr *resp;
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u8 *pos, subtype;
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size_t len;
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resp = (struct eap_hdr *) respData;
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pos = (u8 *) (resp + 1);
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if (respDataLen < sizeof(*resp) + 4 || *pos != EAP_TYPE_SIM ||
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(len = ntohs(resp->length)) > respDataLen) {
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wpa_printf(MSG_INFO, "EAP-SIM: Invalid frame");
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return TRUE;
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}
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subtype = pos[1];
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if (subtype == EAP_SIM_SUBTYPE_CLIENT_ERROR)
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return FALSE;
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switch (data->state) {
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case START:
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if (subtype != EAP_SIM_SUBTYPE_START) {
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wpa_printf(MSG_INFO, "EAP-SIM: Unexpected response "
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"subtype %d", subtype);
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return TRUE;
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}
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break;
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case CHALLENGE:
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if (subtype != EAP_SIM_SUBTYPE_CHALLENGE) {
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wpa_printf(MSG_INFO, "EAP-SIM: Unexpected response "
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"subtype %d", subtype);
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return TRUE;
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}
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break;
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default:
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wpa_printf(MSG_INFO, "EAP-SIM: Unexpected state (%d) for "
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"processing a response", data->state);
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return TRUE;
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}
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return FALSE;
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}
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static int eap_sim_supported_ver(struct eap_sim_data *data, int version)
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{
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return version == EAP_SIM_VERSION;
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}
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static void eap_sim_derive_mk(struct eap_sim_data *data,
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const u8 *identity, size_t identity_len,
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const u8 *nonce_mt, int selected_version,
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int num_chal, const u8 *kc)
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{
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u8 sel_ver[2], ver_list[2];
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const unsigned char *addr[5];
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size_t len[5];
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addr[0] = identity;
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addr[1] = kc;
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addr[2] = nonce_mt;
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addr[3] = ver_list;
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addr[4] = sel_ver;
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len[0] = identity_len;
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len[1] = num_chal * KC_LEN;
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len[2] = EAP_SIM_NONCE_MT_LEN;
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len[3] = sizeof(ver_list);
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len[4] = sizeof(sel_ver);
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ver_list[0] = 0;
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ver_list[1] = EAP_SIM_VERSION;
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sel_ver[0] = selected_version >> 8;
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sel_ver[1] = selected_version & 0xff;
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/* MK = SHA1(Identity|n*Kc|NONCE_MT|Version List|Selected Version) */
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sha1_vector(5, addr, len, data->mk);
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wpa_hexdump_key(MSG_DEBUG, "EAP-SIM: MK", data->mk, EAP_SIM_MK_LEN);
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}
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static void eap_sim_process_start(struct eap_sm *sm,
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struct eap_sim_data *data,
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u8 *respData, size_t respDataLen,
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struct eap_sim_attrs *attr)
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{
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wpa_printf(MSG_DEBUG, "EAP-SIM: Receive start response");
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if (attr->nonce_mt == NULL || attr->selected_version < 0) {
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wpa_printf(MSG_DEBUG, "EAP-SIM: Start/Response missing "
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"required attributes");
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eap_sim_state(data, FAILURE);
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return;
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}
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if (!eap_sim_supported_ver(data, attr->selected_version)) {
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wpa_printf(MSG_DEBUG, "EAP-SIM: Peer selected unsupported "
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"version %d", attr->selected_version);
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eap_sim_state(data, FAILURE);
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return;
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}
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if (attr->identity) {
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free(sm->identity);
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sm->identity = malloc(attr->identity_len);
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if (sm->identity) {
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memcpy(sm->identity, attr->identity,
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attr->identity_len);
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sm->identity_len = attr->identity_len;
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}
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}
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if (sm->identity == NULL || sm->identity_len < 1 ||
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sm->identity[0] != '1') {
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wpa_printf(MSG_DEBUG, "EAP-SIM: Could not get proper permanent"
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" user name");
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eap_sim_state(data, FAILURE);
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return;
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}
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wpa_hexdump_ascii(MSG_DEBUG, "EAP-SIM: Identity",
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sm->identity, sm->identity_len);
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data->num_chal = eap_sim_db_get_gsm_triplets(
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sm->eap_sim_db_priv, sm->identity, sm->identity_len,
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EAP_SIM_MAX_CHAL,
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(u8 *) data->rand, (u8 *) data->kc, (u8 *) data->sres);
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if (data->num_chal < 2) {
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wpa_printf(MSG_INFO, "EAP-SIM: Failed to get GSM "
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"authentication triplets for the peer");
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eap_sim_state(data, FAILURE);
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return;
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}
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memcpy(data->nonce_mt, attr->nonce_mt, EAP_SIM_NONCE_MT_LEN);
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eap_sim_derive_mk(data, sm->identity, sm->identity_len, attr->nonce_mt,
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attr->selected_version, data->num_chal,
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(u8 *) data->kc);
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eap_sim_derive_keys(data->mk, data->k_encr, data->k_aut, data->msk);
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eap_sim_state(data, CHALLENGE);
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}
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static void eap_sim_process_challenge(struct eap_sm *sm,
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struct eap_sim_data *data,
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u8 *respData, size_t respDataLen,
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struct eap_sim_attrs *attr)
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{
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if (attr->mac == NULL ||
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eap_sim_verify_mac(data->k_aut, respData, respDataLen, attr->mac,
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(u8 *) data->sres, data->num_chal * SRES_LEN)) {
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wpa_printf(MSG_WARNING, "EAP-SIM: Challenge message "
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"did not include valid AT_MAC");
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eap_sim_state(data, FAILURE);
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return;
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}
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wpa_printf(MSG_DEBUG, "EAP-SIM: Challenge response includes the "
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"correct AT_MAC");
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eap_sim_state(data, SUCCESS);
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}
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static void eap_sim_process_client_error(struct eap_sm *sm,
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struct eap_sim_data *data,
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u8 *respData, size_t respDataLen,
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struct eap_sim_attrs *attr)
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{
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wpa_printf(MSG_DEBUG, "EAP-SIM: Client reported error %d",
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attr->client_error_code);
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eap_sim_state(data, FAILURE);
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}
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static void eap_sim_process(struct eap_sm *sm, void *priv,
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u8 *respData, size_t respDataLen)
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{
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struct eap_sim_data *data = priv;
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struct eap_hdr *resp;
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u8 *pos, subtype;
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size_t len;
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struct eap_sim_attrs attr;
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resp = (struct eap_hdr *) respData;
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pos = (u8 *) (resp + 1);
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subtype = pos[1];
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len = ntohs(resp->length);
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pos += 4;
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if (eap_sim_parse_attr(pos, respData + len, &attr, 0, 0)) {
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wpa_printf(MSG_DEBUG, "EAP-SIM: Failed to parse attributes");
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eap_sim_state(data, FAILURE);
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return;
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}
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if (subtype == EAP_SIM_SUBTYPE_CLIENT_ERROR) {
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eap_sim_process_client_error(sm, data, respData, len, &attr);
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return;
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}
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switch (data->state) {
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case START:
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eap_sim_process_start(sm, data, respData, len, &attr);
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break;
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case CHALLENGE:
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eap_sim_process_challenge(sm, data, respData, len, &attr);
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break;
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default:
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wpa_printf(MSG_DEBUG, "EAP-SIM: Unknown state %d in "
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"process", data->state);
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break;
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}
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}
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static Boolean eap_sim_isDone(struct eap_sm *sm, void *priv)
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{
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struct eap_sim_data *data = priv;
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return data->state == SUCCESS || data->state == FAILURE;
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}
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static u8 * eap_sim_getKey(struct eap_sm *sm, void *priv, size_t *len)
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{
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struct eap_sim_data *data = priv;
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u8 *key;
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if (data->state != SUCCESS)
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return NULL;
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key = malloc(EAP_SIM_KEYING_DATA_LEN);
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if (key == NULL)
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return NULL;
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memcpy(key, data->msk, EAP_SIM_KEYING_DATA_LEN);
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*len = EAP_SIM_KEYING_DATA_LEN;
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return key;
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}
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static Boolean eap_sim_isSuccess(struct eap_sm *sm, void *priv)
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{
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struct eap_sim_data *data = priv;
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return data->state == SUCCESS;
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}
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const struct eap_method eap_method_sim =
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{
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.method = EAP_TYPE_SIM,
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.name = "SIM",
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.init = eap_sim_init,
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.reset = eap_sim_reset,
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.buildReq = eap_sim_buildReq,
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.check = eap_sim_check,
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.process = eap_sim_process,
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.isDone = eap_sim_isDone,
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.getKey = eap_sim_getKey,
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.isSuccess = eap_sim_isSuccess,
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};
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