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/*
* Copyright (C) 2008-2009 Martin Willi
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#include "eap_aka_3gpp2_card.h"
#include <daemon.h>
typedef struct private_eap_aka_3gpp2_card_t private_eap_aka_3gpp2_card_t;
/**
* Private data of an eap_aka_3gpp2_card_t object.
*/
struct private_eap_aka_3gpp2_card_t {
/**
* Public eap_aka_3gpp2_card_t interface.
*/
eap_aka_3gpp2_card_t public;
/**
* AKA functions
*/
eap_aka_3gpp2_functions_t *f;
/**
* do sequence number checking?
*/
bool seq_check;
/**
* SQN stored in this pseudo-USIM
*/
char sqn[AKA_SQN_LEN];
};
/**
* Functions from eap_aka_3gpp2_provider.c
*/
bool eap_aka_3gpp2_get_k(identification_t *id, char k[AKA_K_LEN]);
void eap_aka_3gpp2_get_sqn(char sqn[AKA_SQN_LEN], int offset);
/**
* Implementation of sim_card_t.get_quintuplet
*/
static status_t get_quintuplet(private_eap_aka_3gpp2_card_t *this,
identification_t *imsi, char rand[AKA_RAND_LEN],
char autn[AKA_AUTN_LEN], char ck[AKA_CK_LEN],
char ik[AKA_IK_LEN], char res[AKA_RES_LEN])
{
char *amf, *mac;
char k[AKA_K_LEN], ak[AKA_AK_LEN], sqn[AKA_SQN_LEN], xmac[AKA_MAC_LEN];
if (!eap_aka_3gpp2_get_k(imsi, k))
{
DBG1(DBG_IKE, "no EAP key found for %Y to authenticate with AKA", imsi);
return FAILED;
}
/* AUTN = SQN xor AK | AMF | MAC */
DBG3(DBG_IKE, "received autn %b", autn, AKA_AUTN_LEN);
DBG3(DBG_IKE, "using K %b", k, AKA_K_LEN);
DBG3(DBG_IKE, "using rand %b", rand, AKA_RAND_LEN);
memcpy(sqn, autn, AKA_SQN_LEN);
amf = autn + AKA_SQN_LEN;
mac = autn + AKA_SQN_LEN + AKA_AMF_LEN;
/* XOR anonymity key AK into SQN to decrypt it */
this->f->f5(this->f, k, rand, ak);
DBG3(DBG_IKE, "using ak %b", ak, AKA_AK_LEN);
memxor(sqn, ak, AKA_SQN_LEN);
DBG3(DBG_IKE, "using sqn %b", sqn, AKA_SQN_LEN);
/* calculate expected MAC and compare against received one */
this->f->f1(this->f, k, rand, sqn, amf, xmac);
if (!memeq(mac, xmac, AKA_MAC_LEN))
{
DBG1(DBG_IKE, "received MAC does not match XMAC");
DBG3(DBG_IKE, "MAC %b\nXMAC %b", mac, AKA_MAC_LEN, xmac, AKA_MAC_LEN);
return FAILED;
}
if (this->seq_check && memcmp(this->sqn, sqn, AKA_SQN_LEN) >= 0)
{
DBG3(DBG_IKE, "received SQN %b\ncurrent SQN %b",
sqn, AKA_SQN_LEN, this->sqn, AKA_SQN_LEN);
return INVALID_STATE;
}
/* update stored SQN to the received one */
memcpy(this->sqn, sqn, AKA_SQN_LEN);
/* CK/IK */
this->f->f3(this->f, k, rand, ck);
this->f->f4(this->f, k, rand, ik);
/* calculate RES */
this->f->f2(this->f, k, rand, res);
return SUCCESS;
}
/**
* Implementation of sim_card_t.resync
*/
static bool resync(private_eap_aka_3gpp2_card_t *this, identification_t *imsi,
char rand[AKA_RAND_LEN], char auts[AKA_AUTS_LEN])
{
char amf[AKA_AMF_LEN], k[AKA_K_LEN], aks[AKA_AK_LEN], macs[AKA_MAC_LEN];
if (!eap_aka_3gpp2_get_k(imsi, k))
{
DBG1(DBG_IKE, "no EAP key found for %Y to resync AKA", imsi);
return FALSE;
}
/* AMF is set to zero in resync */
memset(amf, 0, AKA_AMF_LEN);
this->f->f5star(this->f, k, rand, aks);
this->f->f1star(this->f, k, rand, this->sqn, amf, macs);
/* AUTS = SQN xor AKS | MACS */
memcpy(auts, this->sqn, AKA_SQN_LEN);
memxor(auts, aks, AKA_AK_LEN);
memcpy(auts + AKA_AK_LEN, macs, AKA_MAC_LEN);
return TRUE;
}
/**
* Implementation of eap_aka_3gpp2_card_t.destroy.
*/
static void destroy(private_eap_aka_3gpp2_card_t *this)
{
free(this);
}
/**
* See header
*/
eap_aka_3gpp2_card_t *eap_aka_3gpp2_card_create(eap_aka_3gpp2_functions_t *f)
{
private_eap_aka_3gpp2_card_t *this = malloc_thing(private_eap_aka_3gpp2_card_t);
this->public.card.get_triplet = (bool(*)(sim_card_t*, identification_t *imsi, char rand[SIM_RAND_LEN], char sres[SIM_SRES_LEN], char kc[SIM_KC_LEN]))return_false;
this->public.card.get_quintuplet = (status_t(*)(sim_card_t*, identification_t *imsi, char rand[AKA_RAND_LEN], char autn[AKA_AUTN_LEN], char ck[AKA_CK_LEN], char ik[AKA_IK_LEN], char res[AKA_RES_LEN]))get_quintuplet;
this->public.card.resync = (bool(*)(sim_card_t*, identification_t *imsi, char rand[AKA_RAND_LEN], char auts[AKA_AUTS_LEN]))resync;
this->public.destroy = (void(*)(eap_aka_3gpp2_card_t*))destroy;
this->f = f;
this->seq_check = lib->settings->get_bool(lib->settings,
"charon.plugins.eap_aka_3gpp2.seq_check",
#ifdef SEQ_CHECK /* handle legacy compile time configuration as default */
TRUE);
#else /* !SEQ_CHECK */
FALSE);
#endif /* SEQ_CHECK */
eap_aka_3gpp2_get_sqn(this->sqn, 0);
return &this->public;
}
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