eap_sim.c

IEEE 802.11a/b/g 服务器端AP

/*
 * EAP peer method: EAP-SIM (RFC 4186)
 * Copyright (c) 2004-2008, Jouni Malinen <[e-mail]>
 *
 * 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_config.h"
#include "pcsc_funcs.h"
#include "eap_common/eap_sim_common.h"


struct eap_sim_data {
	u8 *ver_list;
	size_t ver_list_len;
	int selected_version;
	size_t min_num_chal, num_chal;

	u8 kc[3][EAP_SIM_KC_LEN];
	u8 sres[3][EAP_SIM_SRES_LEN];
	u8 nonce_mt[EAP_SIM_NONCE_MT_LEN], nonce_s[EAP_SIM_NONCE_S_LEN];
	u8 mk[EAP_SIM_MK_LEN];
	u8 k_aut[EAP_SIM_K_AUT_LEN];
	u8 k_encr[EAP_SIM_K_ENCR_LEN];
	u8 msk[EAP_SIM_KEYING_DATA_LEN];
	u8 emsk[EAP_EMSK_LEN];
	u8 rand[3][GSM_RAND_LEN];

	int num_id_req, num_notification;
	u8 *pseudonym;
	size_t pseudonym_len;
	u8 *reauth_id;
	size_t reauth_id_len;
	int reauth;
	unsigned int counter, counter_too_small;
	u8 *last_eap_identity;
	size_t last_eap_identity_len;
	enum {
		CONTINUE, RESULT_SUCCESS, RESULT_FAILURE, SUCCESS, FAILURE
	} state;
	int result_ind, use_result_ind;
};


#ifndef CONFIG_NO_STDOUT_DEBUG
static const char * eap_sim_state_txt(int state)
{
	switch (state) {
	case CONTINUE:
		return "CONTINUE";
	case RESULT_SUCCESS:
		return "RESULT_SUCCESS";
	case RESULT_FAILURE:
		return "RESULT_FAILURE";
	case SUCCESS:
		return "SUCCESS";
	case FAILURE:
		return "FAILURE";
	default:
		return "?";
	}
}
#endif /* CONFIG_NO_STDOUT_DEBUG */


static void eap_sim_state(struct eap_sim_data *data, int state)
{
	wpa_printf(MSG_DEBUG, "EAP-SIM: %s -> %s",
		   eap_sim_state_txt(data->state),
		   eap_sim_state_txt(state));
	data->state = state;
}


static void * eap_sim_init(struct eap_sm *sm)
{
	struct eap_sim_data *data;
	struct eap_peer_config *config = eap_get_config(sm);

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

	if (os_get_random(data->nonce_mt, EAP_SIM_NONCE_MT_LEN)) {
		wpa_printf(MSG_WARNING, "EAP-SIM: Failed to get random data "
			   "for NONCE_MT");
		os_free(data);
		return NULL;
	}

	data->min_num_chal = 2;
	if (config && config->phase1) {
		char *pos = os_strstr(config->phase1, "sim_min_num_chal=");
		if (pos) {
			data->min_num_chal = atoi(pos + 17);
			if (data->min_num_chal < 2 || data->min_num_chal > 3) {
				wpa_printf(MSG_WARNING, "EAP-SIM: Invalid "
					   "sim_min_num_chal configuration "
					   "(%lu, expected 2 or 3)",
					   (unsigned long) data->min_num_chal);
				os_free(data);
				return NULL;
			}
			wpa_printf(MSG_DEBUG, "EAP-SIM: Set minimum number of "
				   "challenges to %lu",
				   (unsigned long) data->min_num_chal);
		}

		data->result_ind = os_strstr(config->phase1, "result_ind=1") !=
			NULL;
	}

	eap_sim_state(data, CONTINUE);

	return data;
}


static void eap_sim_deinit(struct eap_sm *sm, void *priv)
{
	struct eap_sim_data *data = priv;
	if (data) {
		os_free(data->ver_list);
		os_free(data->pseudonym);
		os_free(data->reauth_id);
		os_free(data->last_eap_identity);
		os_free(data);
	}
}


static int eap_sim_gsm_auth(struct eap_sm *sm, struct eap_sim_data *data)
{
	wpa_printf(MSG_DEBUG, "EAP-SIM: GSM authentication algorithm");
#ifdef PCSC_FUNCS
	if (scard_gsm_auth(sm->scard_ctx, data->rand[0],
			   data->sres[0], data->kc[0]) ||
	    scard_gsm_auth(sm->scard_ctx, data->rand[1],
			   data->sres[1], data->kc[1]) ||
	    (data->num_chal > 2 &&
	     scard_gsm_auth(sm->scard_ctx, data->rand[2],
			    data->sres[2], data->kc[2]))) {
		wpa_printf(MSG_DEBUG, "EAP-SIM: GSM SIM authentication could "
			   "not be completed");
		return -1;
	}
#else /* PCSC_FUNCS */
	/* These hardcoded Kc and SRES values are used for testing. RAND to
	 * KC/SREC mapping is very bogus as far as real authentication is
	 * concerned, but it is quite useful for cases where the AS is rotating
	 * the order of pre-configured values. */
	{
		size_t i;
		for (i = 0; i < data->num_chal; i++) {
			if (data->rand[i][0] == 0xaa) {
				os_memcpy(data->kc[i],
					  "\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7",
					  EAP_SIM_KC_LEN);
				os_memcpy(data->sres[i], "\xd1\xd2\xd3\xd4",
					  EAP_SIM_SRES_LEN);
			} else if (data->rand[i][0] == 0xbb) {
				os_memcpy(data->kc[i],
					  "\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7",
					  EAP_SIM_KC_LEN);
				os_memcpy(data->sres[i], "\xe1\xe2\xe3\xe4",
					  EAP_SIM_SRES_LEN);
			} else {
				os_memcpy(data->kc[i],
					  "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7",
					  EAP_SIM_KC_LEN);
				os_memcpy(data->sres[i], "\xf1\xf2\xf3\xf4",
					  EAP_SIM_SRES_LEN);
			}
		}
	}
#endif /* PCSC_FUNCS */
	return 0;
}


static int eap_sim_supported_ver(int version)
{
	return version == EAP_SIM_VERSION;
}


#define CLEAR_PSEUDONYM	0x01
#define CLEAR_REAUTH_ID	0x02
#define CLEAR_EAP_ID	0x04

static void eap_sim_clear_identities(struct eap_sim_data *data, int id)
{
	wpa_printf(MSG_DEBUG, "EAP-SIM: forgetting old%s%s%s",
		   id & CLEAR_PSEUDONYM ? " pseudonym" : "",
		   id & CLEAR_REAUTH_ID ? " reauth_id" : "",
		   id & CLEAR_EAP_ID ? " eap_id" : "");
	if (id & CLEAR_PSEUDONYM) {
		os_free(data->pseudonym);
		data->pseudonym = NULL;
		data->pseudonym_len = 0;
	}
	if (id & CLEAR_REAUTH_ID) {
		os_free(data->reauth_id);
		data->reauth_id = NULL;
		data->reauth_id_len = 0;
	}
	if (id & CLEAR_EAP_ID) {
		os_free(data->last_eap_identity);
		data->last_eap_identity = NULL;
		data->last_eap_identity_len = 0;
	}
}


static int eap_sim_learn_ids(struct eap_sim_data *data,
			     struct eap_sim_attrs *attr)
{
	if (attr->next_pseudonym) {
		os_free(data->pseudonym);
		data->pseudonym = os_malloc(attr->next_pseudonym_len);
		if (data->pseudonym == NULL) {
			wpa_printf(MSG_INFO, "EAP-SIM: (encr) No memory for "
				   "next pseudonym");
			return -1;
		}
		os_memcpy(data->pseudonym, attr->next_pseudonym,
			  attr->next_pseudonym_len);
		data->pseudonym_len = attr->next_pseudonym_len;
		wpa_hexdump_ascii(MSG_DEBUG,
				  "EAP-SIM: (encr) AT_NEXT_PSEUDONYM",
				  data->pseudonym,
				  data->pseudonym_len);
	}

	if (attr->next_reauth_id) {
		os_free(data->reauth_id);
		data->reauth_id = os_malloc(attr->next_reauth_id_len);
		if (data->reauth_id == NULL) {
			wpa_printf(MSG_INFO, "EAP-SIM: (encr) No memory for "
				   "next reauth_id");
			return -1;
		}
		os_memcpy(data->reauth_id, attr->next_reauth_id,
			  attr->next_reauth_id_len);
		data->reauth_id_len = attr->next_reauth_id_len;
		wpa_hexdump_ascii(MSG_DEBUG,
				  "EAP-SIM: (encr) AT_NEXT_REAUTH_ID",
				  data->reauth_id,
				  data->reauth_id_len);
	}

	return 0;
}


static struct wpabuf * eap_sim_client_error(struct eap_sim_data *data, u8 id,
					    int err)
{
	struct eap_sim_msg *msg;

	eap_sim_state(data, FAILURE);
	data->num_id_req = 0;
	data->num_notification = 0;

	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, EAP_TYPE_SIM,
			       EAP_SIM_SUBTYPE_CLIENT_ERROR);
	eap_sim_msg_add(msg, EAP_SIM_AT_CLIENT_ERROR_CODE, err, NULL, 0);
	return eap_sim_msg_finish(msg, NULL, NULL, 0);
}


static struct wpabuf * eap_sim_response_start(struct eap_sm *sm,
					      struct eap_sim_data *data, u8 id,
					      enum eap_sim_id_req id_req)
{
	const u8 *identity = NULL;
	size_t identity_len = 0;
	struct eap_sim_msg *msg;

	data->reauth = 0;
	if (id_req == ANY_ID && data->reauth_id) {
		identity = data->reauth_id;
		identity_len = data->reauth_id_len;
		data->reauth = 1;
	} else if ((id_req == ANY_ID || id_req == FULLAUTH_ID) &&
		   data->pseudonym) {
		identity = data->pseudonym;
		identity_len = data->pseudonym_len;
		eap_sim_clear_identities(data, CLEAR_REAUTH_ID);
	} else if (id_req != NO_ID_REQ) {
		identity = eap_get_config_identity(sm, &identity_len);
		if (identity) {
			eap_sim_clear_identities(data, CLEAR_PSEUDONYM |
						 CLEAR_REAUTH_ID);
		}
	}
	if (id_req != NO_ID_REQ)
		eap_sim_clear_identities(data, CLEAR_EAP_ID);

	wpa_printf(MSG_DEBUG, "Generating EAP-SIM Start (id=%d)", id);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id,
			       EAP_TYPE_SIM, EAP_SIM_SUBTYPE_START);
	if (!data->reauth) {
		wpa_hexdump(MSG_DEBUG, "   AT_NONCE_MT",
			    data->nonce_mt, EAP_SIM_NONCE_MT_LEN);
		eap_sim_msg_add(msg, EAP_SIM_AT_NONCE_MT, 0,
				data->nonce_mt, EAP_SIM_NONCE_MT_LEN);
		wpa_printf(MSG_DEBUG, "   AT_SELECTED_VERSION %d",
			   data->selected_version);
		eap_sim_msg_add(msg, EAP_SIM_AT_SELECTED_VERSION,
				data->selected_version, NULL, 0);
	}

	if (identity) {
		wpa_hexdump_ascii(MSG_DEBUG, "   AT_IDENTITY",
				  identity, identity_len);
		eap_sim_msg_add(msg, EAP_SIM_AT_IDENTITY, identity_len,
				identity, identity_len);
	}

	return eap_sim_msg_finish(msg, NULL, NULL, 0);
}


static struct wpabuf * eap_sim_response_challenge(struct eap_sim_data *data,
						  u8 id)
{
	struct eap_sim_msg *msg;

	wpa_printf(MSG_DEBUG, "Generating EAP-SIM Challenge (id=%d)", id);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, EAP_TYPE_SIM,
			       EAP_SIM_SUBTYPE_CHALLENGE);
	if (data->use_result_ind) {
		wpa_printf(MSG_DEBUG, "   AT_RESULT_IND");
		eap_sim_msg_add(msg, EAP_SIM_AT_RESULT_IND, 0, NULL, 0);
	}
	wpa_printf(MSG_DEBUG, "   AT_MAC");
	eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
	return eap_sim_msg_finish(msg, data->k_aut, (u8 *) data->sres,
				  data->num_chal * EAP_SIM_SRES_LEN);
}


static struct wpabuf * eap_sim_response_reauth(struct eap_sim_data *data,
					       u8 id, int counter_too_small)
{
	struct eap_sim_msg *msg;
	unsigned int counter;

	wpa_printf(MSG_DEBUG, "Generating EAP-SIM Reauthentication (id=%d)",
		   id);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, EAP_TYPE_SIM,
			       EAP_SIM_SUBTYPE_REAUTHENTICATION);
	wpa_printf(MSG_DEBUG, "   AT_IV");
	wpa_printf(MSG_DEBUG, "   AT_ENCR_DATA");
	eap_sim_msg_add_encr_start(msg, EAP_SIM_AT_IV, EAP_SIM_AT_ENCR_DATA);

	if (counter_too_small) {
		wpa_printf(MSG_DEBUG, "   *AT_COUNTER_TOO_SMALL");
		eap_sim_msg_add(msg, EAP_SIM_AT_COUNTER_TOO_SMALL, 0, NULL, 0);
		counter = data->counter_too_small;
	} else
		counter = data->counter;

	wpa_printf(MSG_DEBUG, "   *AT_COUNTER %d", counter);
	eap_sim_msg_add(msg, EAP_SIM_AT_COUNTER, counter, NULL, 0);

	if (eap_sim_msg_add_encr_end(msg, data->k_encr, EAP_SIM_AT_PADDING)) {
		wpa_printf(MSG_WARNING, "EAP-SIM: Failed to encrypt "
			   "AT_ENCR_DATA");
		eap_sim_msg_free(msg);
		return NULL;
	}
	if (data->use_result_ind) {
		wpa_printf(MSG_DEBUG, "   AT_RESULT_IND");
		eap_sim_msg_add(msg, EAP_SIM_AT_RESULT_IND, 0, NULL, 0);
	}
	wpa_printf(MSG_DEBUG, "   AT_MAC");
	eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
	return eap_sim_msg_finish(msg, data->k_aut, data->nonce_s,
				  EAP_SIM_NONCE_S_LEN);
}


static struct wpabuf * eap_sim_response_notification(struct eap_sim_data *data,
						     u8 id, u16 notification)
{
	struct eap_sim_msg *msg;
	u8 *k_aut = (notification & 0x4000) == 0 ? data->k_aut : NULL;

	wpa_printf(MSG_DEBUG, "Generating EAP-SIM Notification (id=%d)", id);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id,
			       EAP_TYPE_SIM, EAP_SIM_SUBTYPE_NOTIFICATION);
	wpa_printf(MSG_DEBUG, "   AT_NOTIFICATION");
	eap_sim_msg_add(msg, EAP_SIM_AT_NOTIFICATION, notification, NULL, 0);
	if (k_aut && data->reauth) {
		wpa_printf(MSG_DEBUG, "   AT_IV");
		wpa_printf(MSG_DEBUG, "   AT_ENCR_DATA");
		eap_sim_msg_add_encr_start(msg, EAP_SIM_AT_IV,
					   EAP_SIM_AT_ENCR_DATA);
		wpa_printf(MSG_DEBUG, "   *AT_COUNTER %d", data->counter);
		eap_sim_msg_add(msg, EAP_SIM_AT_COUNTER, data->counter,
				NULL, 0);
		if (eap_sim_msg_add_encr_end(msg, data->k_encr,
					     EAP_SIM_AT_PADDING)) {
			wpa_printf(MSG_WARNING, "EAP-SIM: Failed to encrypt "
				   "AT_ENCR_DATA");
			eap_sim_msg_free(msg);
			return NULL;
		}
	}
	if (k_aut) {
		wpa_printf(MSG_DEBUG, "   AT_MAC");
		eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
	}
	return eap_sim_msg_finish(msg, k_aut, (u8 *) "", 0);
}


static struct wpabuf * eap_sim_process_start(struct eap_sm *sm,
					     struct eap_sim_data *data, u8 id,
					     struct eap_sim_attrs *attr)
{
	int selected_version = -1, id_error;
	size_t i;
	u8 *pos;

	wpa_printf(MSG_DEBUG, "EAP-SIM: subtype Start");
	if (attr->version_list == NULL) {
		wpa_printf(MSG_INFO, "EAP-SIM: No AT_VERSION_LIST in "
			   "SIM/Start");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNSUPPORTED_VERSION);
	}

	os_free(data->ver_list);
	data->ver_list = os_malloc(attr->version_list_len);
	if (data->ver_list == NULL) {
		wpa_printf(MSG_DEBUG, "EAP-SIM: Failed to allocate "
			   "memory for version list");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}
	os_memcpy(data->ver_list, attr->version_list, attr->version_list_len);
	data->ver_list_len = attr->version_list_len;
	pos = data->ver_list;
	for (i = 0; i < data->ver_list_len / 2; i++) {
		int ver = pos[0] * 256 + pos[1];
		pos += 2;
		if (eap_sim_supported_ver(ver)) {
			selected_version = ver;
			break;
		}
	}
	if (selected_version < 0) {
		wpa_printf(MSG_INFO, "EAP-SIM: Could not find a supported "
			   "version");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNSUPPORTED_VERSION);
	}
	wpa_printf(MSG_DEBUG, "EAP-SIM: Selected Version %d",
		   selected_version);
	data->selected_version = selected_version;

	id_error = 0;
	switch (attr->id_req) {
	case NO_ID_REQ:
		break;
	case ANY_ID:
		if (data->num_id_req > 0)
			id_error++;
		data->num_id_req++;
		break;
	case FULLAUTH_ID:
		if (data->num_id_req > 1)
			id_error++;
		data->num_id_req++;
		break;
	case PERMANENT_ID:
		if (data->num_id_req > 2)
			id_error++;
		data->num_id_req++;
		break;
	}
	if (id_error) {
		wpa_printf(MSG_INFO, "EAP-SIM: Too many ID requests "
			   "used within one authentication");
		return eap_sim_client_error(data, id,
					    EAP_SIM_UNABLE_TO_PROCESS_PACKET);
	}

	return eap_sim_response_start(sm, data, id, attr->id_req);
}


static struct wpabuf * eap_sim_process_challenge(struct eap_sm *sm,
						 struct eap_sim_data *data,
						 u8 id,
						 const struct wpabuf *reqData,
						 struct eap_sim_attrs *attr)
{
	const u8 *identity;
	size_t identity_len;
	struct eap_sim_attrs eattr;

	wpa_printf(MSG_DEBUG, "EAP-SIM: subtype Challenge");
	data->reauth = 0;
	if (!attr->mac || !attr->rand) {
		wpa_printf(MSG_WARNING, "EAP-SIM: Challenge message "