/*
 * EAP peer method: EAP-AKA (RFC 4187) and EAP-AKA' (RFC 5448)
 * Copyright (c) 2004-2012, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "includes.h"

#include "common.h"
#include "pcsc_funcs.h"
#include "crypto/crypto.h"
#include "crypto/sha1.h"
#include "crypto/sha256.h"
#include "crypto/milenage.h"
#include "eap_common/eap_sim_common.h"
#include "eap_config.h"
#include "eap_i.h"


struct eap_aka_data {
	u8 ik[EAP_AKA_IK_LEN], ck[EAP_AKA_CK_LEN], res[EAP_AKA_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_AKA_PRIME_K_AUT_LEN];
	u8 k_encr[EAP_SIM_K_ENCR_LEN];
	u8 k_re[EAP_AKA_PRIME_K_RE_LEN]; /* EAP-AKA' only */
	u8 msk[EAP_SIM_KEYING_DATA_LEN];
	u8 emsk[EAP_EMSK_LEN];
	u8 rand[EAP_AKA_RAND_LEN], autn[EAP_AKA_AUTN_LEN];
	u8 auts[EAP_AKA_AUTS_LEN];
	u8 reauth_mac[EAP_SIM_MAC_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, SUCCESS, FAILURE
	} state;

	struct wpabuf *id_msgs;
	int prev_id;
	int result_ind, use_result_ind;
	int use_pseudonym;
	u8 eap_method;
	u8 *network_name;
	size_t network_name_len;
	u16 kdf;
	int kdf_negotiation;
	u16 last_kdf_attrs[EAP_AKA_PRIME_KDF_MAX];
	size_t last_kdf_count;
	int error_code;
};


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


static void eap_aka_state(struct eap_aka_data *data, int state)
{
	wpa_printf(MSG_DEBUG, "EAP-AKA: %s -> %s",
		   eap_aka_state_txt(data->state),
		   eap_aka_state_txt(state));
	data->state = state;
}


static void * eap_aka_init(struct eap_sm *sm)
{
	struct eap_aka_data *data;
	const char *phase1 = eap_get_config_phase1(sm);
	struct eap_peer_config *config = eap_get_config(sm);

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

	data->eap_method = EAP_TYPE_AKA;

	/* Zero is a valid error code, so we need to initialize */
	data->error_code = NO_EAP_METHOD_ERROR;

	eap_aka_state(data, CONTINUE);
	data->prev_id = -1;

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

	data->use_pseudonym = !sm->init_phase2;
	if (config && config->anonymous_identity && data->use_pseudonym) {
		data->pseudonym = os_malloc(config->anonymous_identity_len);
		if (data->pseudonym) {
			os_memcpy(data->pseudonym, config->anonymous_identity,
				  config->anonymous_identity_len);
			data->pseudonym_len = config->anonymous_identity_len;
		}
	}

	return data;
}


#ifdef EAP_AKA_PRIME
static void * eap_aka_prime_init(struct eap_sm *sm)
{
	struct eap_aka_data *data = eap_aka_init(sm);
	if (data == NULL)
		return NULL;
	data->eap_method = EAP_TYPE_AKA_PRIME;
	return data;
}
#endif /* EAP_AKA_PRIME */


static void eap_aka_clear_keys(struct eap_aka_data *data, int reauth)
{
	if (!reauth) {
		os_memset(data->mk, 0, EAP_SIM_MK_LEN);
		os_memset(data->k_aut, 0, EAP_AKA_PRIME_K_AUT_LEN);
		os_memset(data->k_encr, 0, EAP_SIM_K_ENCR_LEN);
		os_memset(data->k_re, 0, EAP_AKA_PRIME_K_RE_LEN);
	}
	os_memset(data->msk, 0, EAP_SIM_KEYING_DATA_LEN);
	os_memset(data->emsk, 0, EAP_EMSK_LEN);
	os_memset(data->autn, 0, EAP_AKA_AUTN_LEN);
	os_memset(data->auts, 0, EAP_AKA_AUTS_LEN);
}


static void eap_aka_deinit(struct eap_sm *sm, void *priv)
{
	struct eap_aka_data *data = priv;
	if (data) {
		os_free(data->pseudonym);
		os_free(data->reauth_id);
		os_free(data->last_eap_identity);
		wpabuf_free(data->id_msgs);
		os_free(data->network_name);
		eap_aka_clear_keys(data, 0);
		os_free(data);
	}
}


static int eap_aka_ext_sim_req(struct eap_sm *sm, struct eap_aka_data *data)
{
	char req[200], *pos, *end;

	wpa_printf(MSG_DEBUG, "EAP-AKA: Use external USIM processing");
	pos = req;
	end = pos + sizeof(req);
	pos += os_snprintf(pos, end - pos, "UMTS-AUTH");
	pos += os_snprintf(pos, end - pos, ":");
	pos += wpa_snprintf_hex(pos, end - pos, data->rand, EAP_AKA_RAND_LEN);
	pos += os_snprintf(pos, end - pos, ":");
	wpa_snprintf_hex(pos, end - pos, data->autn, EAP_AKA_AUTN_LEN);

	eap_sm_request_sim(sm, req);
	return 1;
}


static int eap_aka_ext_sim_result(struct eap_sm *sm, struct eap_aka_data *data,
				  struct eap_peer_config *conf)
{
	char *resp, *pos;

	wpa_printf(MSG_DEBUG,
		   "EAP-AKA: Use result from external USIM processing");

	resp = conf->external_sim_resp;
	conf->external_sim_resp = NULL;

	if (os_strncmp(resp, "UMTS-AUTS:", 10) == 0) {
		pos = resp + 10;
		if (hexstr2bin(pos, data->auts, EAP_AKA_AUTS_LEN) < 0)
			goto invalid;
		wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: AUTS", data->auts,
				EAP_AKA_AUTS_LEN);
		os_free(resp);
		return -2;
	}

	if (os_strncmp(resp, "UMTS-AUTH:", 10) != 0) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: Unrecognized external USIM processing response");
		os_free(resp);
		return -1;
	}

	pos = resp + 10;
	wpa_hexdump(MSG_DEBUG, "EAP-AKA: RAND", data->rand, EAP_AKA_RAND_LEN);

	if (hexstr2bin(pos, data->ik, EAP_AKA_IK_LEN) < 0)
		goto invalid;
	wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: IK", data->ik, EAP_AKA_IK_LEN);
	pos += EAP_AKA_IK_LEN * 2;
	if (*pos != ':')
		goto invalid;
	pos++;

	if (hexstr2bin(pos, data->ck, EAP_AKA_CK_LEN) < 0)
		goto invalid;
	wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: CK", data->ck, EAP_AKA_CK_LEN);
	pos += EAP_AKA_CK_LEN * 2;
	if (*pos != ':')
		goto invalid;
	pos++;

	data->res_len = os_strlen(pos) / 2;
	if (data->res_len > EAP_AKA_RES_MAX_LEN) {
		data->res_len = 0;
		goto invalid;
	}
	if (hexstr2bin(pos, data->res, data->res_len) < 0)
		goto invalid;
	wpa_hexdump_key(MSG_DEBUG, "EAP-AKA: RES", data->res, data->res_len);

	os_free(resp);
	return 0;

invalid:
	wpa_printf(MSG_DEBUG, "EAP-AKA: Invalid external USIM processing UMTS-AUTH response");
	os_free(resp);
	return -1;
}


static int eap_aka_umts_auth(struct eap_sm *sm, struct eap_aka_data *data)
{
	struct eap_peer_config *conf;

	wpa_printf(MSG_DEBUG, "EAP-AKA: UMTS authentication algorithm");

	conf = eap_get_config(sm);
	if (conf == NULL)
		return -1;

	if (sm->external_sim) {
		if (conf->external_sim_resp)
			return eap_aka_ext_sim_result(sm, data, conf);
		else
			return eap_aka_ext_sim_req(sm, data);
	}

	if (conf->pcsc) {
		return scard_umts_auth(sm->scard_ctx, data->rand,
				       data->autn, data->res, &data->res_len,
				       data->ik, data->ck, data->auts);
	}

#ifdef CONFIG_USIM_SIMULATOR
	if (conf->password) {
		u8 opc[16], k[16], sqn[6];
		const char *pos;
		wpa_printf(MSG_DEBUG, "EAP-AKA: Use internal Milenage "
			   "implementation for UMTS authentication");
		if (conf->password_len < 78) {
			wpa_printf(MSG_DEBUG, "EAP-AKA: invalid Milenage "
				   "password");
			return -1;
		}
		pos = (const char *) conf->password;
		if (hexstr2bin(pos, k, 16))
			return -1;
		pos += 32;
		if (*pos != ':')
			return -1;
		pos++;

		if (hexstr2bin(pos, opc, 16))
			return -1;
		pos += 32;
		if (*pos != ':')
			return -1;
		pos++;

		if (hexstr2bin(pos, sqn, 6))
			return -1;

		return milenage_check(opc, k, sqn, data->rand, data->autn,
				      data->ik, data->ck,
				      data->res, &data->res_len, data->auts);
	}
#endif /* CONFIG_USIM_SIMULATOR */

#ifdef CONFIG_USIM_HARDCODED
	wpa_printf(MSG_DEBUG, "EAP-AKA: Use hardcoded Kc and SRES values for "
		   "testing");

	/* These hardcoded Kc and SRES values are used for testing.
	 * Could consider making them configurable. */
	os_memset(data->res, '2', EAP_AKA_RES_MAX_LEN);
	data->res_len = EAP_AKA_RES_MAX_LEN;
	os_memset(data->ik, '3', EAP_AKA_IK_LEN);
	os_memset(data->ck, '4', EAP_AKA_CK_LEN);
	{
		u8 autn[EAP_AKA_AUTN_LEN];
		os_memset(autn, '1', EAP_AKA_AUTN_LEN);
		if (os_memcmp_const(autn, data->autn, EAP_AKA_AUTN_LEN) != 0) {
			wpa_printf(MSG_WARNING, "EAP-AKA: AUTN did not match "
				   "with expected value");
			return -1;
		}
	}
#if 0
	{
		static int test_resync = 1;
		if (test_resync) {
			/* Test Resynchronization */
			test_resync = 0;
			return -2;
		}
	}
#endif
	return 0;

#else /* CONFIG_USIM_HARDCODED */

	wpa_printf(MSG_DEBUG, "EAP-AKA: No UMTS authentication algorithm "
		   "enabled");
	return -1;

#endif /* CONFIG_USIM_HARDCODED */
}


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

static void eap_aka_clear_identities(struct eap_sm *sm,
				     struct eap_aka_data *data, int id)
{
	if ((id & CLEAR_PSEUDONYM) && data->pseudonym) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: forgetting old pseudonym");
		os_free(data->pseudonym);
		data->pseudonym = NULL;
		data->pseudonym_len = 0;
		if (data->use_pseudonym)
			eap_set_anon_id(sm, NULL, 0);
	}
	if ((id & CLEAR_REAUTH_ID) && data->reauth_id) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: forgetting old reauth_id");
		os_free(data->reauth_id);
		data->reauth_id = NULL;
		data->reauth_id_len = 0;
	}
	if ((id & CLEAR_EAP_ID) && data->last_eap_identity) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: forgetting old eap_id");
		os_free(data->last_eap_identity);
		data->last_eap_identity = NULL;
		data->last_eap_identity_len = 0;
	}
}


static int eap_aka_learn_ids(struct eap_sm *sm, struct eap_aka_data *data,
			     struct eap_sim_attrs *attr)
{
	if (attr->next_pseudonym) {
		const u8 *identity = NULL;
		size_t identity_len = 0;
		const u8 *realm = NULL;
		size_t realm_len = 0;

		wpa_hexdump_ascii(MSG_DEBUG,
				  "EAP-AKA: (encr) AT_NEXT_PSEUDONYM",
				  attr->next_pseudonym,
				  attr->next_pseudonym_len);
		os_free(data->pseudonym);
		/* Look for the realm of the permanent identity */
		identity = eap_get_config_identity(sm, &identity_len);
		if (identity) {
			for (realm = identity, realm_len = identity_len;
			     realm_len > 0; realm_len--, realm++) {
				if (*realm == '@')
					break;
			}
		}
		data->pseudonym = os_malloc(attr->next_pseudonym_len +
					    realm_len);
		if (data->pseudonym == NULL) {
			wpa_printf(MSG_INFO, "EAP-AKA: (encr) No memory for "
				   "next pseudonym");
			data->pseudonym_len = 0;
			return -1;
		}
		os_memcpy(data->pseudonym, attr->next_pseudonym,
			  attr->next_pseudonym_len);
		if (realm_len) {
			os_memcpy(data->pseudonym + attr->next_pseudonym_len,
				  realm, realm_len);
		}
		data->pseudonym_len = attr->next_pseudonym_len + realm_len;
		if (data->use_pseudonym)
			eap_set_anon_id(sm, data->pseudonym,
					data->pseudonym_len);
	}

	if (attr->next_reauth_id) {
		os_free(data->reauth_id);
		data->reauth_id = os_memdup(attr->next_reauth_id,
					    attr->next_reauth_id_len);
		if (data->reauth_id == NULL) {
			wpa_printf(MSG_INFO, "EAP-AKA: (encr) No memory for "
				   "next reauth_id");
			data->reauth_id_len = 0;
			return -1;
		}
		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 int eap_aka_add_id_msg(struct eap_aka_data *data,
			      const struct wpabuf *msg1,
			      const struct wpabuf *msg2)
{
	size_t len;

	if (!msg1)
		return -1;
	len = wpabuf_len(msg1);
	if (msg2)
		len += wpabuf_len(msg2);

	if (!data->id_msgs) {
		data->id_msgs = wpabuf_alloc(len);
		if (!data->id_msgs)
			return -1;
	} else if (wpabuf_resize(&data->id_msgs, len) < 0) {
		return -1;
	}

	wpabuf_put_buf(data->id_msgs, msg1);
	if (msg2)
		wpabuf_put_buf(data->id_msgs, msg2);

	return 0;
}


static void eap_aka_add_checkcode(struct eap_aka_data *data,
				  struct eap_sim_msg *msg)
{
	const u8 *addr;
	size_t len;
	u8 hash[SHA256_MAC_LEN];

	wpa_printf(MSG_DEBUG, "   AT_CHECKCODE");

	if (data->id_msgs == NULL) {
		/*
		 * No EAP-AKA/Identity packets were exchanged - send empty
		 * checkcode.
		 */
		eap_sim_msg_add(msg, EAP_SIM_AT_CHECKCODE, 0, NULL, 0);
		return;
	}

	/* Checkcode is SHA1/SHA256 hash over all EAP-AKA/Identity packets. */
	addr = wpabuf_head(data->id_msgs);
	len = wpabuf_len(data->id_msgs);
	wpa_hexdump(MSG_MSGDUMP, "EAP-AKA: AT_CHECKCODE data", addr, len);
#ifdef EAP_AKA_PRIME
	if (data->eap_method == EAP_TYPE_AKA_PRIME)
		sha256_vector(1, &addr, &len, hash);
	else
#endif /* EAP_AKA_PRIME */
		sha1_vector(1, &addr, &len, hash);

	eap_sim_msg_add(msg, EAP_SIM_AT_CHECKCODE, 0, hash,
			data->eap_method == EAP_TYPE_AKA_PRIME ?
			EAP_AKA_PRIME_CHECKCODE_LEN : EAP_AKA_CHECKCODE_LEN);
}


static int eap_aka_verify_checkcode(struct eap_aka_data *data,
				    const u8 *checkcode, size_t checkcode_len)
{
	const u8 *addr;
	size_t len;
	u8 hash[SHA256_MAC_LEN];
	size_t hash_len;

	if (checkcode == NULL)
		return -1;

	if (data->id_msgs == NULL) {
		if (checkcode_len != 0) {
			wpa_printf(MSG_DEBUG, "EAP-AKA: Checkcode from server "
				   "indicates that AKA/Identity messages were "
				   "used, but they were not");
			return -1;
		}
		return 0;
	}

	hash_len = data->eap_method == EAP_TYPE_AKA_PRIME ?
		EAP_AKA_PRIME_CHECKCODE_LEN : EAP_AKA_CHECKCODE_LEN;

	if (checkcode_len != hash_len) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: Checkcode from server "
			   "indicates that AKA/Identity message were not "
			   "used, but they were");
		return -1;
	}

	/* Checkcode is SHA1/SHA256 hash over all EAP-AKA/Identity packets. */
	addr = wpabuf_head(data->id_msgs);
	len = wpabuf_len(data->id_msgs);
#ifdef EAP_AKA_PRIME
	if (data->eap_method == EAP_TYPE_AKA_PRIME)
		sha256_vector(1, &addr, &len, hash);
	else
#endif /* EAP_AKA_PRIME */
		sha1_vector(1, &addr, &len, hash);

	if (os_memcmp_const(hash, checkcode, hash_len) != 0) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: Mismatch in AT_CHECKCODE");
		return -1;
	}

	return 0;
}


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

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

	wpa_printf(MSG_DEBUG, "EAP-AKA: Send Client-Error (error code %d)",
		   err);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
			       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, data->eap_method, NULL, NULL, 0);
}


static struct wpabuf * eap_aka_authentication_reject(struct eap_aka_data *data,
						     u8 id)
{
	struct eap_sim_msg *msg;

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

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


static struct wpabuf * eap_aka_synchronization_failure(
	struct eap_aka_data *data, u8 id, struct eap_sim_attrs *attr)
{
	struct eap_sim_msg *msg;

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

	wpa_printf(MSG_DEBUG, "Generating EAP-AKA Synchronization-Failure "
		   "(id=%d)", id);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
			       EAP_AKA_SUBTYPE_SYNCHRONIZATION_FAILURE);
	wpa_printf(MSG_DEBUG, "   AT_AUTS");
	eap_sim_msg_add_full(msg, EAP_SIM_AT_AUTS, data->auts,
			     EAP_AKA_AUTS_LEN);
	if (data->eap_method == EAP_TYPE_AKA_PRIME) {
		size_t i;

		for (i = 0; i < attr->kdf_count; i++) {
			wpa_printf(MSG_DEBUG, "   AT_KDF");
			eap_sim_msg_add(msg, EAP_SIM_AT_KDF, attr->kdf[i],
					NULL, 0);
		}
	}
	return eap_sim_msg_finish(msg, data->eap_method, NULL, NULL, 0);
}


static struct wpabuf * eap_aka_response_identity(struct eap_sm *sm,
						 struct eap_aka_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 &&
		   !eap_sim_anonymous_username(data->pseudonym,
					       data->pseudonym_len)) {
		identity = data->pseudonym;
		identity_len = data->pseudonym_len;
		eap_aka_clear_identities(sm, data, CLEAR_REAUTH_ID);
	} else if (id_req != NO_ID_REQ) {
		identity = eap_get_config_identity(sm, &identity_len);
		if (identity) {
			int ids = CLEAR_PSEUDONYM | CLEAR_REAUTH_ID;

			if (data->pseudonym &&
			    eap_sim_anonymous_username(data->pseudonym,
						       data->pseudonym_len))
				ids &= ~CLEAR_PSEUDONYM;
			eap_aka_clear_identities(sm, data, ids);
		}
	}
	if (id_req != NO_ID_REQ)
		eap_aka_clear_identities(sm, data, CLEAR_EAP_ID);

	wpa_printf(MSG_DEBUG, "Generating EAP-AKA Identity (id=%d)", id);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
			       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, data->eap_method, NULL, NULL, 0);
}


static struct wpabuf * eap_aka_response_challenge(struct eap_aka_data *data,
						  u8 id)
{
	struct eap_sim_msg *msg;

	wpa_printf(MSG_DEBUG, "Generating EAP-AKA Challenge (id=%d)", id);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
			       EAP_AKA_SUBTYPE_CHALLENGE);
	wpa_printf(MSG_DEBUG, "   AT_RES");
	eap_sim_msg_add(msg, EAP_SIM_AT_RES, data->res_len * 8,
			data->res, data->res_len);
	eap_aka_add_checkcode(data, msg);
	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->eap_method, data->k_aut, (u8 *) "",
				  0);
}


static struct wpabuf * eap_aka_response_reauth(struct eap_aka_data *data,
					       u8 id, 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)",
		   id);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
			       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;
	}
	eap_aka_add_checkcode(data, msg);
	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->eap_method, data->k_aut, nonce_s,
				  EAP_SIM_NONCE_S_LEN);
}


static struct wpabuf * eap_aka_response_notification(struct eap_aka_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-AKA Notification (id=%d)", id);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
			       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, data->eap_method, k_aut, (u8 *) "", 0);
}


static struct wpabuf * eap_aka_process_identity(struct eap_sm *sm,
						struct eap_aka_data *data,
						u8 id,
						const struct wpabuf *reqData,
						struct eap_sim_attrs *attr)
{
	int id_error;
	struct wpabuf *buf;

	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(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	buf = eap_aka_response_identity(sm, data, id, attr->id_req);

	if (data->prev_id != id) {
		if (eap_aka_add_id_msg(data, reqData, buf) < 0) {
			wpa_printf(MSG_INFO,
				   "EAP-AKA: Failed to store ID messages");
			wpabuf_free(buf);
			return eap_aka_client_error(
				data, id, EAP_AKA_UNABLE_TO_PROCESS_PACKET);
		}
		data->prev_id = id;
	}

	return buf;
}


static int eap_aka_verify_mac(struct eap_aka_data *data,
			      const struct wpabuf *req,
			      const u8 *mac, const u8 *extra,
			      size_t extra_len)
{
	if (data->eap_method == EAP_TYPE_AKA_PRIME)
		return eap_sim_verify_mac_sha256(data->k_aut, req, mac, extra,
						 extra_len);
	return eap_sim_verify_mac(data->k_aut, req, mac, extra, extra_len);
}


#ifdef EAP_AKA_PRIME
static struct wpabuf * eap_aka_prime_kdf_select(struct eap_aka_data *data,
						u8 id, u16 kdf)
{
	struct eap_sim_msg *msg;

	data->kdf_negotiation = 1;
	data->kdf = kdf;
	wpa_printf(MSG_DEBUG, "Generating EAP-AKA Challenge (id=%d) (KDF "
		   "select)", id);
	msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, data->eap_method,
			       EAP_AKA_SUBTYPE_CHALLENGE);
	wpa_printf(MSG_DEBUG, "   AT_KDF");
	eap_sim_msg_add(msg, EAP_SIM_AT_KDF, kdf, NULL, 0);
	return eap_sim_msg_finish(msg, data->eap_method, NULL, NULL, 0);
}


static struct wpabuf * eap_aka_prime_kdf_neg(struct eap_aka_data *data,
					     u8 id, struct eap_sim_attrs *attr)
{
	size_t i;

	for (i = 0; i < attr->kdf_count; i++) {
		if (attr->kdf[i] == EAP_AKA_PRIME_KDF) {
			os_memcpy(data->last_kdf_attrs, attr->kdf,
				  sizeof(u16) * attr->kdf_count);
			data->last_kdf_count = attr->kdf_count;
			return eap_aka_prime_kdf_select(data, id,
							EAP_AKA_PRIME_KDF);
		}
	}

	/* No matching KDF found - fail authentication as if AUTN had been
	 * incorrect */
	return eap_aka_authentication_reject(data, id);
}


static int eap_aka_prime_kdf_valid(struct eap_aka_data *data,
				   struct eap_sim_attrs *attr)
{
	size_t i, j;

	if (attr->kdf_count == 0)
		return 0;

	/* The only allowed (and required) duplication of a KDF is the addition
	 * of the selected KDF into the beginning of the list. */

	if (data->kdf_negotiation) {
		/* When the peer receives the new EAP-Request/AKA'-Challenge
		 * message, must check only requested change occurred in the
		 * list of AT_KDF attributes. If there are any other changes,
		 * the peer must behave like the case that AT_MAC had been
		 * incorrect and authentication is failed. These are defined in
		 * EAP-AKA' specification RFC 5448, Section 3.2. */
		if (attr->kdf[0] != data->kdf) {
			wpa_printf(MSG_WARNING, "EAP-AKA': The server did not "
				   "accept the selected KDF");
			return -1;
		}

		if (attr->kdf_count > EAP_AKA_PRIME_KDF_MAX ||
		    attr->kdf_count != data->last_kdf_count + 1) {
			wpa_printf(MSG_WARNING,
				   "EAP-AKA': The length of KDF attributes is wrong");
			return -1;
		}

		for (i = 1; i < attr->kdf_count; i++) {
			if (attr->kdf[i] != data->last_kdf_attrs[i - 1]) {
				wpa_printf(MSG_WARNING,
					   "EAP-AKA': The KDF attributes except selected KDF are not same as original one");
				return -1;
			}
		}
	}

	for (i = data->kdf ? 1 : 0; i < attr->kdf_count; i++) {
		for (j = i + 1; j < attr->kdf_count; j++) {
			if (attr->kdf[i] == attr->kdf[j]) {
				wpa_printf(MSG_WARNING, "EAP-AKA': The server "
					   "included a duplicated KDF");
				return 0;
			}
		}
	}

	return 1;
}
#endif /* EAP_AKA_PRIME */


static struct wpabuf * eap_aka_process_challenge(struct eap_sm *sm,
						 struct eap_aka_data *data,
						 u8 id,
						 const struct wpabuf *reqData,
						 struct eap_sim_attrs *attr)
{
	const u8 *identity;
	size_t identity_len;
	int res;
	struct eap_sim_attrs eattr;

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

	if (attr->checkcode &&
	    eap_aka_verify_checkcode(data, attr->checkcode,
				     attr->checkcode_len)) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Invalid AT_CHECKCODE in the "
			   "message");
#ifdef TEST_FUZZ
		wpa_printf(MSG_INFO,
			   "TEST: Ignore AT_CHECKCODE mismatch for fuzz testing");
#else /* TEST_FUZZ */
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
#endif /* TEST_FUZZ */
	}

#ifdef EAP_AKA_PRIME
	if (data->eap_method == EAP_TYPE_AKA_PRIME) {
		if (!attr->kdf_input || attr->kdf_input_len == 0) {
			wpa_printf(MSG_WARNING, "EAP-AKA': Challenge message "
				   "did not include non-empty AT_KDF_INPUT");
			/* Fail authentication as if AUTN had been incorrect */
			return eap_aka_authentication_reject(data, id);
		}
		os_free(data->network_name);
		data->network_name = os_memdup(attr->kdf_input,
					       attr->kdf_input_len);
		if (data->network_name == NULL) {
			wpa_printf(MSG_WARNING, "EAP-AKA': No memory for "
				   "storing Network Name");
			return eap_aka_authentication_reject(data, id);
		}
		data->network_name_len = attr->kdf_input_len;
		wpa_hexdump_ascii(MSG_DEBUG, "EAP-AKA': Network Name "
				  "(AT_KDF_INPUT)",
				  data->network_name, data->network_name_len);
		/* TODO: check Network Name per 3GPP.33.402 */

		res = eap_aka_prime_kdf_valid(data, attr);
		if (res == 0)
			return eap_aka_authentication_reject(data, id);
		else if (res == -1)
			return eap_aka_client_error(
				data, id, EAP_AKA_UNABLE_TO_PROCESS_PACKET);

		if (attr->kdf[0] != EAP_AKA_PRIME_KDF)
			return eap_aka_prime_kdf_neg(data, id, attr);

		data->kdf = EAP_AKA_PRIME_KDF;
		wpa_printf(MSG_DEBUG, "EAP-AKA': KDF %d selected", data->kdf);
	}

	if (data->eap_method == EAP_TYPE_AKA && attr->bidding) {
		u16 flags = WPA_GET_BE16(attr->bidding);
		if ((flags & EAP_AKA_BIDDING_FLAG_D) &&
		    eap_allowed_method(sm, EAP_VENDOR_IETF,
				       EAP_TYPE_AKA_PRIME)) {
			wpa_printf(MSG_WARNING, "EAP-AKA: Bidding down from "
				   "AKA' to AKA detected");
			/* Fail authentication as if AUTN had been incorrect */
			return eap_aka_authentication_reject(data, id);
		}
	}
#endif /* EAP_AKA_PRIME */

	data->reauth = 0;
	if (!attr->mac || !attr->rand || !attr->autn) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Challenge message "
			   "did not include%s%s%s",
			   !attr->mac ? " AT_MAC" : "",
			   !attr->rand ? " AT_RAND" : "",
			   !attr->autn ? " AT_AUTN" : "");
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}
	os_memcpy(data->rand, attr->rand, EAP_AKA_RAND_LEN);
	os_memcpy(data->autn, attr->autn, EAP_AKA_AUTN_LEN);

	res = eap_aka_umts_auth(sm, data);
	if (res == -1) {
		wpa_printf(MSG_WARNING, "EAP-AKA: UMTS authentication "
			   "failed (AUTN)");
		return eap_aka_authentication_reject(data, id);
	} else if (res == -2) {
		wpa_printf(MSG_WARNING, "EAP-AKA: UMTS authentication "
			   "failed (AUTN seq# -> AUTS)");
		return eap_aka_synchronization_failure(data, id, attr);
	} else if (res > 0) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: Wait for external USIM processing");
		return NULL;
	} else if (res) {
		wpa_printf(MSG_WARNING, "EAP-AKA: UMTS authentication failed");
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}
#ifdef EAP_AKA_PRIME
	if (data->eap_method == EAP_TYPE_AKA_PRIME) {
		/* Note: AUTN = (SQN ^ AK) || AMF || MAC which gives us the
		 * needed 6-octet SQN ^ AK for CK',IK' derivation */
		u16 amf = WPA_GET_BE16(data->autn + 6);
		if (!(amf & 0x8000)) {
			wpa_printf(MSG_WARNING, "EAP-AKA': AMF separation bit "
				   "not set (AMF=0x%4x)", amf);
			return eap_aka_authentication_reject(data, id);
		}
		eap_aka_prime_derive_ck_ik_prime(data->ck, data->ik,
						 data->autn,
						 data->network_name,
						 data->network_name_len);
	}
#endif /* EAP_AKA_PRIME */
	if (data->last_eap_identity) {
		identity = data->last_eap_identity;
		identity_len = data->last_eap_identity_len;
	} else if (data->pseudonym &&
		   !eap_sim_anonymous_username(data->pseudonym,
					       data->pseudonym_len)) {
		identity = data->pseudonym;
		identity_len = data->pseudonym_len;
	} else {
		struct eap_peer_config *config;

		config = eap_get_config(sm);
		if (config && config->imsi_identity) {
			identity = config->imsi_identity;
			identity_len = config->imsi_identity_len;
		} else {
			identity = eap_get_config_identity(sm, &identity_len);
		}
	}
	wpa_hexdump_ascii(MSG_DEBUG, "EAP-AKA: Selected identity for MK "
			  "derivation", identity, identity_len);
	if (data->eap_method == EAP_TYPE_AKA_PRIME) {
		eap_aka_prime_derive_keys(identity, identity_len, data->ik,
					  data->ck, data->k_encr, data->k_aut,
					  data->k_re, data->msk, data->emsk);
	} else {
		eap_aka_derive_mk(identity, identity_len, data->ik, data->ck,
				  data->mk);
		eap_sim_derive_keys(data->mk, data->k_encr, data->k_aut,
				    data->msk, data->emsk);
	}
	if (eap_aka_verify_mac(data, reqData, attr->mac, (u8 *) "", 0)) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Challenge message "
			   "used invalid AT_MAC");
#ifdef TEST_FUZZ
		wpa_printf(MSG_INFO,
			   "TEST: Ignore AT_MAC mismatch for fuzz testing");
#else /* TEST_FUZZ */
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
#endif /* TEST_FUZZ */
	}

	/* Old reauthentication identity must not be used anymore. In
	 * other words, if no new identities are received, full
	 * authentication will be used on next reauthentication (using
	 * pseudonym identity or permanent identity). */
	eap_aka_clear_identities(sm, data, CLEAR_REAUTH_ID | CLEAR_EAP_ID);

	if (attr->encr_data) {
		u8 *decrypted;
		decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
					       attr->encr_data_len, attr->iv,
					       &eattr, 0);
		if (decrypted == NULL) {
			return eap_aka_client_error(
				data, id, EAP_AKA_UNABLE_TO_PROCESS_PACKET);
		}
		eap_aka_learn_ids(sm, data, &eattr);
		os_free(decrypted);
	}

	if (data->result_ind && attr->result_ind)
		data->use_result_ind = 1;

	if (data->state != FAILURE) {
		eap_aka_state(data, data->use_result_ind ?
			      RESULT_SUCCESS : SUCCESS);
	}

	data->num_id_req = 0;
	data->num_notification = 0;
	/* RFC 4187 specifies that counter is initialized to one after
	 * fullauth, but initializing it to zero makes it easier to implement
	 * reauth verification. */
	data->counter = 0;
	return eap_aka_response_challenge(data, id);
}


static int eap_aka_process_notification_reauth(struct eap_aka_data *data,
					       struct eap_sim_attrs *attr)
{
	struct eap_sim_attrs eattr;
	u8 *decrypted;

	if (attr->encr_data == NULL || attr->iv == NULL) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Notification message after "
			   "reauth did not include encrypted data");
		return -1;
	}

	decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
				       attr->encr_data_len, attr->iv, &eattr,
				       0);
	if (decrypted == NULL) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Failed to parse encrypted "
			   "data from notification message");
		return -1;
	}

	if (eattr.counter < 0 || (size_t) eattr.counter != data->counter) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Counter in notification "
			   "message does not match with counter in reauth "
			   "message");
		os_free(decrypted);
		return -1;
	}

	os_free(decrypted);
	return 0;
}


static int eap_aka_process_notification_auth(struct eap_aka_data *data,
					     const struct wpabuf *reqData,
					     struct eap_sim_attrs *attr)
{
	if (attr->mac == NULL) {
		wpa_printf(MSG_INFO, "EAP-AKA: no AT_MAC in after_auth "
			   "Notification message");
		return -1;
	}

	if (eap_aka_verify_mac(data, reqData, attr->mac, (u8 *) "", 0)) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Notification message "
			   "used invalid AT_MAC");
		return -1;
	}

	if (data->reauth &&
	    eap_aka_process_notification_reauth(data, attr)) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Invalid notification "
			   "message after reauth");
		return -1;
	}

	return 0;
}


static struct wpabuf * eap_aka_process_notification(
	struct eap_sm *sm, struct eap_aka_data *data, u8 id,
	const struct wpabuf *reqData, struct eap_sim_attrs *attr)
{
	wpa_printf(MSG_DEBUG, "EAP-AKA: subtype Notification");
	if (data->num_notification > 0) {
		wpa_printf(MSG_INFO, "EAP-AKA: too many notification "
			   "rounds (only one allowed)");
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}
	data->num_notification++;
	if (attr->notification == -1) {
		wpa_printf(MSG_INFO, "EAP-AKA: no AT_NOTIFICATION in "
			   "Notification message");
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	if ((attr->notification & 0x4000) == 0 &&
	    eap_aka_process_notification_auth(data, reqData, attr)) {
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	eap_sim_report_notification(sm->msg_ctx, attr->notification, 1);
	if (attr->notification >= 0 && attr->notification < 32768) {
		data->error_code = attr->notification;
		eap_aka_state(data, FAILURE);
	} else if (attr->notification == EAP_SIM_SUCCESS &&
		   data->state == RESULT_SUCCESS)
		eap_aka_state(data, SUCCESS);
	return eap_aka_response_notification(data, id, attr->notification);
}


static struct wpabuf * eap_aka_process_reauthentication(
	struct eap_sm *sm, struct eap_aka_data *data, u8 id,
	const struct wpabuf *reqData, struct eap_sim_attrs *attr)
{
	struct eap_sim_attrs eattr;
	u8 *decrypted;

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

	if (attr->checkcode &&
	    eap_aka_verify_checkcode(data, attr->checkcode,
				     attr->checkcode_len)) {
#ifdef TEST_FUZZ
		wpa_printf(MSG_INFO,
			   "TEST: Ignore AT_CHECKCODE mismatch for fuzz testing");
#else /* TEST_FUZZ */
		wpa_printf(MSG_WARNING, "EAP-AKA: Invalid AT_CHECKCODE in the "
			   "message");
#endif /* TEST_FUZZ */
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	if (data->reauth_id == NULL) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Server is trying "
			   "reauthentication, but no reauth_id available");
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	data->reauth = 1;
	if (eap_aka_verify_mac(data, reqData, attr->mac, (u8 *) "", 0)) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Reauthentication "
			   "did not have valid AT_MAC");
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	/* At this stage the received MAC has been verified. Use this MAC for
	 * reauth Session-Id calculation if all other checks pass.
	 * The peer does not use the local MAC but the received MAC in deriving
	 * Session-Id. */
	os_memcpy(data->reauth_mac, attr->mac, EAP_SIM_MAC_LEN);
	wpa_hexdump(MSG_DEBUG, "EAP-AKA: Server MAC",
		    data->reauth_mac, EAP_SIM_MAC_LEN);

	if (attr->encr_data == NULL || attr->iv == NULL) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Reauthentication "
			   "message did not include encrypted data");
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
				       attr->encr_data_len, attr->iv, &eattr,
				       0);
	if (decrypted == NULL) {
		wpa_printf(MSG_WARNING, "EAP-AKA: Failed to parse encrypted "
			   "data from reauthentication message");
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	if (eattr.nonce_s == NULL || eattr.counter < 0) {
		wpa_printf(MSG_INFO, "EAP-AKA: (encr) No%s%s in reauth packet",
			   !eattr.nonce_s ? " AT_NONCE_S" : "",
			   eattr.counter < 0 ? " AT_COUNTER" : "");
		os_free(decrypted);
		return eap_aka_client_error(data, id,
					    EAP_AKA_UNABLE_TO_PROCESS_PACKET);
	}

	if (eattr.counter < 0 || (size_t) eattr.counter <= data->counter) {
		struct wpabuf *res;
		wpa_printf(MSG_INFO, "EAP-AKA: (encr) Invalid counter "
			   "(%d <= %d)", eattr.counter, data->counter);
		data->counter_too_small = eattr.counter;

		/* Reply using Re-auth w/ AT_COUNTER_TOO_SMALL. The current
		 * reauth_id must not be used to start a new reauthentication.
		 * However, since it was used in the last EAP-Response-Identity
		 * packet, it has to saved for the following fullauth to be
		 * used in MK derivation. */
		os_free(data->last_eap_identity);
		data->last_eap_identity = data->reauth_id;
		data->last_eap_identity_len = data->reauth_id_len;
		data->reauth_id = NULL;
		data->reauth_id_len = 0;

		res = eap_aka_response_reauth(data, id, 1, eattr.nonce_s);
		os_free(decrypted);

		return res;
	}
	data->counter = eattr.counter;

	os_memcpy(data->nonce_s, eattr.nonce_s, EAP_SIM_NONCE_S_LEN);
	wpa_hexdump(MSG_DEBUG, "EAP-AKA: (encr) AT_NONCE_S",
		    data->nonce_s, EAP_SIM_NONCE_S_LEN);

	if (data->eap_method == EAP_TYPE_AKA_PRIME) {
		eap_aka_prime_derive_keys_reauth(data->k_re, data->counter,
						 data->reauth_id,
						 data->reauth_id_len,
						 data->nonce_s,
						 data->msk, data->emsk);
	} else {
		eap_sim_derive_keys_reauth(data->counter, data->reauth_id,
					   data->reauth_id_len,
					   data->nonce_s, data->mk,
					   data->msk, data->emsk);
	}
	eap_aka_clear_identities(sm, data, CLEAR_REAUTH_ID | CLEAR_EAP_ID);
	eap_aka_learn_ids(sm, data, &eattr);

	if (data->result_ind && attr->result_ind)
		data->use_result_ind = 1;

	if (data->state != FAILURE) {
		eap_aka_state(data, data->use_result_ind ?
			      RESULT_SUCCESS : SUCCESS);
	}

	data->num_id_req = 0;
	data->num_notification = 0;
	if (data->counter > EAP_AKA_MAX_FAST_REAUTHS) {
		wpa_printf(MSG_DEBUG, "EAP-AKA: Maximum number of "
			   "fast reauths performed - force fullauth");
		eap_aka_clear_identities(sm, data,
					 CLEAR_REAUTH_ID | CLEAR_EAP_ID);
	}
	os_free(decrypted);
	return eap_aka_response_reauth(data, id, 0, data->nonce_s);
}


static struct wpabuf * eap_aka_process(struct eap_sm *sm, void *priv,
				       struct eap_method_ret *ret,
				       const struct wpabuf *reqData)
{
	struct eap_aka_data *data = priv;
	const struct eap_hdr *req;
	u8 subtype, id;
	struct wpabuf *res;
	const u8 *pos;
	struct eap_sim_attrs attr;
	size_t len;

	wpa_hexdump_buf(MSG_DEBUG, "EAP-AKA: EAP data", reqData);
	if (eap_get_config_identity(sm, &len) == NULL) {
		wpa_printf(MSG_INFO, "EAP-AKA: Identity not configured");
		eap_sm_request_identity(sm);
		ret->ignore = true;
		return NULL;
	}

	pos = eap_hdr_validate(EAP_VENDOR_IETF, data->eap_method, reqData,
			       &len);
	if (pos == NULL || len < 3) {
		ret->ignore = true;
		return NULL;
	}
	req = wpabuf_head(reqData);
	id = req->identifier;
	len = be_to_host16(req->length);

	ret->ignore = false;
	ret->methodState = METHOD_MAY_CONT;
	ret->decision = DECISION_FAIL;
	ret->allowNotifications = true;

	subtype = *pos++;
	wpa_printf(MSG_DEBUG, "EAP-AKA: Subtype=%d", subtype);
	pos += 2; /* Reserved */

	if (eap_sim_parse_attr(pos, wpabuf_head_u8(reqData) + len, &attr,
			       data->eap_method == EAP_TYPE_AKA_PRIME ? 2 : 1,
			       0)) {
		res = eap_aka_client_error(data, id,
					   EAP_AKA_UNABLE_TO_PROCESS_PACKET);
		goto done;
	}

	switch (subtype) {
	case EAP_AKA_SUBTYPE_IDENTITY:
		res = eap_aka_process_identity(sm, data, id, reqData, &attr);
		break;
	case EAP_AKA_SUBTYPE_CHALLENGE:
		res = eap_aka_process_challenge(sm, data, id, reqData, &attr);
		break;
	case EAP_AKA_SUBTYPE_NOTIFICATION:
		res = eap_aka_process_notification(sm, data, id, reqData,
						   &attr);
		break;
	case EAP_AKA_SUBTYPE_REAUTHENTICATION:
		res = eap_aka_process_reauthentication(sm, data, id, reqData,
						       &attr);
		break;
	case EAP_AKA_SUBTYPE_CLIENT_ERROR:
		wpa_printf(MSG_DEBUG, "EAP-AKA: subtype Client-Error");
		res = eap_aka_client_error(data, id,
					   EAP_AKA_UNABLE_TO_PROCESS_PACKET);
		break;
	default:
		wpa_printf(MSG_DEBUG, "EAP-AKA: Unknown subtype=%d", subtype);
		res = eap_aka_client_error(data, id,
					   EAP_AKA_UNABLE_TO_PROCESS_PACKET);
		break;
	}

done:
	if (data->state == FAILURE) {
		ret->decision = DECISION_FAIL;
		ret->methodState = METHOD_DONE;
	} else if (data->state == SUCCESS) {
		ret->decision = data->use_result_ind ?
			DECISION_UNCOND_SUCC : DECISION_COND_SUCC;
		/*
		 * It is possible for the server to reply with AKA
		 * Notification, so we must allow the method to continue and
		 * not only accept EAP-Success at this point.
		 */
		ret->methodState = data->use_result_ind ?
			METHOD_DONE : METHOD_MAY_CONT;
	} else if (data->state == RESULT_SUCCESS)
		ret->methodState = METHOD_CONT;

	if (ret->methodState == METHOD_DONE) {
		ret->allowNotifications = false;
	}

	return res;
}


static bool eap_aka_has_reauth_data(struct eap_sm *sm, void *priv)
{
	struct eap_aka_data *data = priv;
	return data->pseudonym || data->reauth_id;
}


static void eap_aka_deinit_for_reauth(struct eap_sm *sm, void *priv)
{
	struct eap_aka_data *data = priv;
	eap_aka_clear_identities(sm, data, CLEAR_EAP_ID);
	data->prev_id = -1;
	wpabuf_free(data->id_msgs);
	data->id_msgs = NULL;
	data->use_result_ind = 0;
	data->kdf_negotiation = 0;
	eap_aka_clear_keys(data, 1);
}


static void * eap_aka_init_for_reauth(struct eap_sm *sm, void *priv)
{
	struct eap_aka_data *data = priv;
	data->num_id_req = 0;
	data->num_notification = 0;
	eap_aka_state(data, CONTINUE);
	return priv;
}


static const u8 * eap_aka_get_identity(struct eap_sm *sm, void *priv,
				       size_t *len)
{
	struct eap_aka_data *data = priv;

	if (data->reauth_id) {
		*len = data->reauth_id_len;
		return data->reauth_id;
	}

	if (data->pseudonym) {
		*len = data->pseudonym_len;
		return data->pseudonym;
	}

	return NULL;
}


static bool eap_aka_isKeyAvailable(struct eap_sm *sm, void *priv)
{
	struct eap_aka_data *data = priv;
	return data->state == SUCCESS;
}


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

	if (data->state != SUCCESS)
		return NULL;

	key = os_memdup(data->msk, EAP_SIM_KEYING_DATA_LEN);
	if (key == NULL)
		return NULL;

	*len = EAP_SIM_KEYING_DATA_LEN;

	return key;
}


static u8 * eap_aka_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
{
	struct eap_aka_data *data = priv;
	u8 *id;

	if (data->state != SUCCESS)
		return NULL;

	if (!data->reauth)
		*len = 1 + EAP_AKA_RAND_LEN + EAP_AKA_AUTN_LEN;
	else
		*len = 1 + EAP_SIM_NONCE_S_LEN + EAP_SIM_MAC_LEN;
	id = os_malloc(*len);
	if (id == NULL)
		return NULL;

	id[0] = data->eap_method;
	if (!data->reauth) {
		os_memcpy(id + 1, data->rand, EAP_AKA_RAND_LEN);
		os_memcpy(id + 1 + EAP_AKA_RAND_LEN, data->autn,
			  EAP_AKA_AUTN_LEN);
	} else {
		os_memcpy(id + 1, data->nonce_s, EAP_SIM_NONCE_S_LEN);
		os_memcpy(id + 1 + EAP_SIM_NONCE_S_LEN, data->reauth_mac,
			  EAP_SIM_MAC_LEN);
	}
	wpa_hexdump(MSG_DEBUG, "EAP-AKA: Derived Session-Id", id, *len);

	return id;
}


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

	if (data->state != SUCCESS)
		return NULL;

	key = os_memdup(data->emsk, EAP_EMSK_LEN);
	if (key == NULL)
		return NULL;

	*len = EAP_EMSK_LEN;

	return key;
}


static int eap_aka_get_error_code(void *priv)
{
	struct eap_aka_data *data = priv;
	int current_data_error;

	if (!data)
		return NO_EAP_METHOD_ERROR;

	current_data_error = data->error_code;

	/* Now reset for next transaction */
	data->error_code = NO_EAP_METHOD_ERROR;

	return current_data_error;
}


int eap_peer_aka_register(void)
{
	struct eap_method *eap;

	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
				    EAP_VENDOR_IETF, EAP_TYPE_AKA, "AKA");
	if (eap == NULL)
		return -1;

	eap->init = eap_aka_init;
	eap->deinit = eap_aka_deinit;
	eap->process = eap_aka_process;
	eap->isKeyAvailable = eap_aka_isKeyAvailable;
	eap->getKey = eap_aka_getKey;
	eap->getSessionId = eap_aka_get_session_id;
	eap->has_reauth_data = eap_aka_has_reauth_data;
	eap->deinit_for_reauth = eap_aka_deinit_for_reauth;
	eap->init_for_reauth = eap_aka_init_for_reauth;
	eap->get_identity = eap_aka_get_identity;
	eap->get_emsk = eap_aka_get_emsk;
	eap->get_error_code = eap_aka_get_error_code;

	return eap_peer_method_register(eap);
}


#ifdef EAP_AKA_PRIME
int eap_peer_aka_prime_register(void)
{
	struct eap_method *eap;

	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
				    EAP_VENDOR_IETF, EAP_TYPE_AKA_PRIME,
				    "AKA'");
	if (eap == NULL)
		return -1;

	eap->init = eap_aka_prime_init;
	eap->deinit = eap_aka_deinit;
	eap->process = eap_aka_process;
	eap->isKeyAvailable = eap_aka_isKeyAvailable;
	eap->getKey = eap_aka_getKey;
	eap->getSessionId = eap_aka_get_session_id;
	eap->has_reauth_data = eap_aka_has_reauth_data;
	eap->deinit_for_reauth = eap_aka_deinit_for_reauth;
	eap->init_for_reauth = eap_aka_init_for_reauth;
	eap->get_identity = eap_aka_get_identity;
	eap->get_emsk = eap_aka_get_emsk;
	eap->get_error_code = eap_aka_get_error_code;

	return eap_peer_method_register(eap);
}
#endif /* EAP_AKA_PRIME */