eap_aka.c

WPA在Linux下实现的原代码 WPA在Linux下实现的原代码

/*
 * WPA Supplicant / EAP-AKA (draft-arkko-pppext-eap-aka-12.txt)
 * Copyright (c) 2004-2005, 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 <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "common.h"
#include "eap_i.h"
#include "wpa_supplicant.h"
#include "config_ssid.h"
#include "crypto.h"
#include "pcsc_funcs.h"
#include "eap_sim_common.h"

/* EAP-AKA Subtypes */
#define EAP_AKA_SUBTYPE_CHALLENGE 1
#define EAP_AKA_SUBTYPE_AUTHENTICATION_REJECT 2
#define EAP_AKA_SUBTYPE_SYNCHRONIZATION_FAILURE 4
#define EAP_AKA_SUBTYPE_IDENTITY 5
#define EAP_AKA_SUBTYPE_NOTIFICATION 12
#define EAP_AKA_SUBTYPE_REAUTHENTICATION 13
#define EAP_AKA_SUBTYPE_CLIENT_ERROR 14

/* AT_CLIENT_ERROR_CODE error codes */
#define EAP_AKA_UNABLE_TO_PROCESS_PACKET 0

#define AKA_AUTS_LEN 14
#define RES_MAX_LEN 16
#define IK_LEN 16
#define CK_LEN 16
#define EAP_AKA_MAX_FAST_REAUTHS 1000

struct eap_aka_data {
	u8 ik[IK_LEN], ck[CK_LEN], res[RES_MAX_LEN];
	size_t res_len;
	u8 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 rand[AKA_RAND_LEN], autn[AKA_AUTN_LEN];
	u8 auts[AKA_AUTS_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, SUCCESS, FAILURE } state;
};


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

	data->state = CONTINUE;

	return data;
}


static void eap_aka_deinit(struct eap_sm *sm, void *priv)
{
	struct eap_aka_data *data = priv;
	if (data) {
		free(data->pseudonym);
		free(data->reauth_id);
		free(data->last_eap_identity);
		free(data);
	}
}


static int eap_aka_umts_auth(struct eap_sm *sm, struct eap_aka_data *data)
{
	wpa_printf(MSG_DEBUG, "EAP-AKA: UMTS authentication algorithm");
#ifdef PCSC_FUNCS
	return scard_umts_auth(sm->scard_ctx, data->rand,
			       data->autn, data->res, &data->res_len,
			       data->ik, data->ck, data->auts);
#else /* PCSC_FUNCS */
	/* These hardcoded Kc and SRES values are used for testing.
	 * Could consider making them configurable. */
	memset(data->res, '2', RES_MAX_LEN);
	data->res_len = 16;
	memset(data->ik, '3', IK_LEN);
	memset(data->ck, '4', CK_LEN);
	{
		u8 autn[AKA_AUTN_LEN];
		memset(autn, '1', AKA_AUTN_LEN);
		if (memcmp(autn, data->autn, AKA_AUTN_LEN) != 0) {
			wpa_printf(MSG_WARNING, "EAP-AKA: AUTN did not match "
				   "with expected value");
			return -1;
		}
	}
	return 0;
#endif /* PCSC_FUNCS */
}


static void eap_aka_derive_mk(struct eap_aka_data *data,
			      const u8 *identity, size_t identity_len)
{
	const u8 *addr[3];
	size_t len[3];

	addr[0] = identity;
	len[0] = identity_len;
	addr[1] = data->ik;
	len[1] = IK_LEN;
	addr[2] = data->ck;
	len[2] = CK_LEN;

	/* MK = SHA1(Identity|IK|CK) */
	sha1_vector(3, addr, len, data->mk);
	wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: IK", data->ik, IK_LEN);
	wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: CK", data->ck, CK_LEN);
	wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: MK", data->mk, EAP_SIM_MK_LEN);
}


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

static void eap_aka_clear_identities(struct eap_aka_data *data, int id)
{
	wpa_printf(MSG_DEBUG, "EAP-AKA: 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) {
		free(data->pseudonym);
		data->pseudonym = NULL;
		data->pseudonym_len = 0;
	}
	if (id & CLEAR_REAUTH_ID) {
		free(data->reauth_id);
		data->reauth_id = NULL;
		data->reauth_id_len = 0;
	}
	if (id & CLEAR_EAP_ID) {
		free(data->last_eap_identity);
		data->last_eap_identity = NULL;
		data->last_eap_identity_len = 0;
	}
}


static int eap_aka_learn_ids(struct eap_aka_data *data,
			     struct eap_sim_attrs *attr)
{
	if (attr->next_pseudonym) {
		free(data->pseudonym);
		data->pseudonym = malloc(attr->next_pseudonym_len);
		if (data->pseudonym == NULL) {
			wpa_printf(MSG_INFO, "EAP-AKA: (encr) No memory for "
				   "next pseudonym");
			return -1;
		}
		memcpy(data->pseudonym, attr->next_pseudonym,
		       attr->next_pseudonym_len);
		data->pseudonym_len = attr->next_pseudonym_len;
		wpa_hexdump_ascii(MSG_DEBUG,
				  "EAP-AKA: (encr) AT_NEXT_PSEUDONYM",
				  data->pseudonym,
				  data->pseudonym_len);
	}

	if (attr->next_reauth_id) {
		free(data->reauth_id);
		data->reauth_id = malloc(attr->next_reauth_id_len);
		if (data->reauth_id == NULL) {
			wpa_printf(MSG_INFO, "EAP-AKA: (encr) No memory for "
				   "next reauth_id");
			return -1;
		}
		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-AKA: (encr) AT_NEXT_REAUTH_ID",
				  data->reauth_id,
				  data->reauth_id_len);
	}

	return 0;
}


static u8 * eap_aka_client_error(struct eap_sm *sm, struct eap_aka_data *data,
				 const struct eap_hdr *req,
				 size_t *respDataLen, int err)
{
	struct eap_sim_msg *msg;

	data->state = FAILURE;
	data->num_id_req = 0;
	data->num_notification = 0;

	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
			       EAP_TYPE_AKA, EAP_AKA_SUBTYPE_CLIENT_ERROR);
	eap_sim_msg_add(msg, EAP_SIM_AT_CLIENT_ERROR_CODE, err, NULL, 0);
	return eap_sim_msg_finish(msg, respDataLen, NULL, NULL, 0);
}


static u8 * eap_aka_authentication_reject(struct eap_sm *sm,
					  struct eap_aka_data *data,
					  const struct eap_hdr *req,
					  size_t *respDataLen)
{
	struct eap_sim_msg *msg;

	data->state = FAILURE;
	data->num_id_req = 0;
	data->num_notification = 0;

	wpa_printf(MSG_DEBUG, "Generating EAP-AKA Authentication-Reject "
		   "(id=%d)", req->identifier);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
			       EAP_TYPE_AKA,
			       EAP_AKA_SUBTYPE_AUTHENTICATION_REJECT);
	return eap_sim_msg_finish(msg, respDataLen, NULL, NULL, 0);
}


static u8 * eap_aka_synchronization_failure(struct eap_sm *sm,
					    struct eap_aka_data *data,
					    const struct eap_hdr *req,
					    size_t *respDataLen)
{
	struct eap_sim_msg *msg;

	data->state = FAILURE;
	data->num_id_req = 0;
	data->num_notification = 0;

	wpa_printf(MSG_DEBUG, "Generating EAP-AKA Synchronization-Failure "
		   "(id=%d)", req->identifier);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
			       EAP_TYPE_AKA,
			       EAP_AKA_SUBTYPE_SYNCHRONIZATION_FAILURE);
	wpa_printf(MSG_DEBUG, "   AT_AUTS");
	eap_sim_msg_add_full(msg, EAP_SIM_AT_AUTS, data->auts, AKA_AUTS_LEN);
	return eap_sim_msg_finish(msg, respDataLen, NULL, NULL, 0);
}


static u8 * eap_aka_response_identity(struct eap_sm *sm,
				      struct eap_aka_data *data,
				      const struct eap_hdr *req,
				      size_t *respDataLen,
				      enum eap_sim_id_req id_req)
{
	struct wpa_ssid *config = eap_get_config(sm);
	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_aka_clear_identities(data, CLEAR_REAUTH_ID);
	} else if (id_req != NO_ID_REQ && config && config->identity) {
		identity = config->identity;
		identity_len = config->identity_len;
		eap_aka_clear_identities(data,
					 CLEAR_PSEUDONYM | CLEAR_REAUTH_ID);
	}
	if (id_req != NO_ID_REQ)
		eap_aka_clear_identities(data, CLEAR_EAP_ID);

	wpa_printf(MSG_DEBUG, "Generating EAP-AKA Identity (id=%d)",
		   req->identifier);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
			       EAP_TYPE_AKA, EAP_AKA_SUBTYPE_IDENTITY);

	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, respDataLen, NULL, NULL, 0);
}


static u8 * eap_aka_response_challenge(struct eap_sm *sm,
				       struct eap_aka_data *data,
				       const struct eap_hdr *req,
				       size_t *respDataLen)
{
	struct eap_sim_msg *msg;

	wpa_printf(MSG_DEBUG, "Generating EAP-AKA Challenge (id=%d)",
		   req->identifier);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
			       EAP_TYPE_AKA, EAP_AKA_SUBTYPE_CHALLENGE);
	wpa_printf(MSG_DEBUG, "   AT_RES");
	eap_sim_msg_add(msg, EAP_SIM_AT_RES, data->res_len,
			data->res, data->res_len);
	wpa_printf(MSG_DEBUG, "   AT_MAC");
	eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
	return eap_sim_msg_finish(msg, respDataLen, data->k_aut, (u8 *) "", 0);
}


static u8 * eap_aka_response_reauth(struct eap_sm *sm,
				    struct eap_aka_data *data,
				    const struct eap_hdr *req,
				    size_t *respDataLen, int counter_too_small,
				    const u8 *nonce_s)
{
	struct eap_sim_msg *msg;
	unsigned int counter;

	wpa_printf(MSG_DEBUG, "Generating EAP-AKA Reauthentication (id=%d)",
		   req->identifier);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
			       EAP_TYPE_AKA,
			       EAP_AKA_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-AKA: Failed to encrypt "
			   "AT_ENCR_DATA");
		eap_sim_msg_free(msg);
		return NULL;
	}
	wpa_printf(MSG_DEBUG, "   AT_MAC");
	eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
	return eap_sim_msg_finish(msg, respDataLen, data->k_aut, nonce_s,
				  EAP_SIM_NONCE_S_LEN);
}


static u8 * eap_aka_response_notification(struct eap_sm *sm,
					  struct eap_aka_data *data,
					  const struct eap_hdr *req,
					  size_t *respDataLen,
					  u16 notification)
{
	struct eap_sim_msg *msg;
	u8 *k_aut = (notification & 0x4000) == 0 ? data->k_aut : NULL;

	wpa_printf(MSG_DEBUG, "Generating EAP-AKA Notification (id=%d)",
		   req->identifier);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, req->identifier,
			       EAP_TYPE_AKA, EAP_AKA_SUBTYPE_NOTIFICATION);
	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-AKA: 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, respDataLen, k_aut, (u8 *) "", 0);
}


static u8 * eap_aka_process_identity(struct eap_sm *sm,
				     struct eap_aka_data *data,
				     const struct eap_hdr *req,
				     size_t reqDataLen,
				     size_t *respDataLen,
				     struct eap_sim_attrs *attr)
{
	int id_error;

	wpa_printf(MSG_DEBUG, "EAP-AKA: subtype Identity");

	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-AKA: Too many ID requests "
			   "used within one authentication");
		return eap_aka_client_error(sm, data, req, respDataLen,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	return eap_aka_response_identity(sm, data, req, respDataLen,
					 attr->id_req);
}


static u8 * eap_aka_process_challenge(struct eap_sm *sm,
				      struct eap_aka_data *data,
				      const struct eap_hdr *req,
				      size_t reqDataLen,
				      size_t *respDataLen,
				      struct eap_sim_attrs *attr)
{
	struct wpa_ssid *config = eap_get_config(sm);
	u8 *identity;
	size_t identity_len;
	int res;
	struct eap_sim_attrs eattr;

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