strongswan/src/libcharon/plugins/eap_aka_3gpp/eap_aka_3gpp_functions.c

365 lines
9.7 KiB
C

/*
* Copyright (C) 2017 Tobias Brunner
* Copyright (C) 2008-2009 Martin Willi
* HSR 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.
*/
/*
* Copyright (C) 2015 Thomas Strangert
* Polystar System AB, Sweden
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "eap_aka_3gpp_functions.h"
#include <limits.h>
#include <ctype.h>
#include <daemon.h>
typedef struct private_eap_aka_3gpp_functions_t private_eap_aka_3gpp_functions_t;
/**
* Private data of an eap_aka_3gpp_functions_t object.
*/
struct private_eap_aka_3gpp_functions_t {
/**
* Public eap_aka_3gpp_functions_t interface.
*/
eap_aka_3gpp_functions_t public;
/**
* AES instance
*/
crypter_t *crypter;
};
/*
* Described in header
*/
bool eap_aka_3gpp_get_k_opc(identification_t *id, uint8_t k[AKA_K_LEN],
uint8_t opc[AKA_OPC_LEN])
{
shared_key_t *shared;
chunk_t key;
shared = lib->credmgr->get_shared(lib->credmgr, SHARED_EAP, id, NULL);
if (!shared)
{
return FALSE;
}
key = shared->get_key(shared);
if (key.len == AKA_K_LEN)
{
memcpy(k, key.ptr, AKA_K_LEN);
/* set OPc to a neutral default value, harmless to XOR with */
memset(opc, '\0', AKA_OPC_LEN);
}
else if (key.len == AKA_K_LEN + AKA_OPC_LEN)
{
memcpy(k, key.ptr, AKA_K_LEN);
memcpy(opc, key.ptr + AKA_K_LEN, AKA_OPC_LEN);
}
else
{
DBG1(DBG_IKE, "invalid EAP K or K+OPc key found for %Y to authenticate "
"with AKA, should be a %d or %d byte long binary value", id,
AKA_K_LEN, AKA_K_LEN + AKA_OPC_LEN);
shared->destroy(shared);
return FALSE;
}
shared->destroy(shared);
return TRUE;
}
/*
* Described in header
*/
void eap_aka_3gpp_get_sqn(uint8_t sqn[AKA_SQN_LEN], int offset)
{
timeval_t time;
gettimeofday(&time, NULL);
/* set sqn to an integer containing 4 bytes seconds + 2 bytes usecs */
time.tv_sec = htonl(time.tv_sec + offset);
/* usec's are never larger than 0x000f423f, so we shift the 12 first bits */
time.tv_usec = htonl(time.tv_usec << 12);
memcpy(sqn, (uint8_t*)&time.tv_sec + sizeof(time_t) - 4, 4);
memcpy(sqn + 4, &time.tv_usec, 2);
}
static bool f1andf1star(private_eap_aka_3gpp_functions_t *this,
const uint8_t k[AKA_K_LEN], const uint8_t opc[AKA_OPC_LEN],
const uint8_t rand[AKA_RAND_LEN], const uint8_t sqn[AKA_SQN_LEN],
const uint8_t amf[AKA_AMF_LEN], uint8_t mac[16])
{
uint8_t i, data[16], in[16], iv[16] = { 0 };
if (!this->crypter->set_key(this->crypter,
chunk_create((uint8_t*)k, AKA_K_LEN)))
{
return FALSE;
}
/* XOR RAND and OPc */
memcpy(data, rand, sizeof(data));
memxor(data, opc, sizeof(data));
if (!this->crypter->encrypt(this->crypter, chunk_create(data, sizeof(data)),
chunk_create(iv, sizeof(iv)), NULL))
{
return FALSE;
}
/* concatenate SQN || AMF ||SQN || AMF */
memcpy(in, sqn, 6);
memcpy(&in[6], amf, 2);
memcpy(&in[8], in, 8);
/* XOR opc and in, rotate by r1=64, and XOR
* on the constant c1 (which is all zeroes) and finally the output above */
for (i = 0; i < 16; i++)
{
data[(i + 8) % 16] ^= in[i] ^ opc[i];
}
if (!this->crypter->encrypt(this->crypter, chunk_create(data, sizeof(data)),
chunk_create(iv, sizeof(iv)), NULL))
{
return FALSE;
}
memxor(data, opc, sizeof(data));
memcpy(mac, data, 16);
return TRUE;
}
METHOD(eap_aka_3gpp_functions_t, f1, bool,
private_eap_aka_3gpp_functions_t *this, const uint8_t k[AKA_K_LEN],
const uint8_t opc[AKA_OPC_LEN], const uint8_t rand[AKA_RAND_LEN],
const uint8_t sqn[AKA_SQN_LEN], const uint8_t amf[AKA_AMF_LEN],
uint8_t maca[AKA_MAC_LEN])
{
uint8_t mac[16];
if (!f1andf1star(this, k, opc, rand, sqn, amf, mac))
{
return FALSE;
}
/* only diff between f1 and f1* is here:
* f1 uses bytes 0-7 as MAC-A
* f1* uses bytes 8-15 as MAC-S */
memcpy(maca, mac, AKA_MAC_LEN);
return TRUE;
}
METHOD(eap_aka_3gpp_functions_t, f1star, bool,
private_eap_aka_3gpp_functions_t *this, const uint8_t k[AKA_K_LEN],
const uint8_t opc[AKA_OPC_LEN], const uint8_t rand[AKA_RAND_LEN],
const uint8_t sqn[AKA_SQN_LEN], const uint8_t amf[AKA_AMF_LEN],
uint8_t macs[AKA_MAC_LEN])
{
uint8_t mac[16];
if (!f1andf1star(this, k, opc, rand, sqn, amf, mac))
{
return FALSE;
}
/* only diff between f1 and f1* is here:
* f1 uses bytes 0-7 as MAC-A
* f1* uses bytes 8-15 as MAC-S */
memcpy(macs, &mac[8], AKA_MAC_LEN);
return TRUE;
}
METHOD(eap_aka_3gpp_functions_t, f2345, bool,
private_eap_aka_3gpp_functions_t *this, const uint8_t k[AKA_K_LEN],
const uint8_t opc[AKA_OPC_LEN], const uint8_t rand[AKA_RAND_LEN],
uint8_t res[AKA_RES_LEN], uint8_t ck[AKA_CK_LEN], uint8_t ik[AKA_IK_LEN],
uint8_t ak[AKA_AK_LEN])
{
uint8_t data[16], iv[16] = { 0 };
chunk_t temp;
uint8_t i;
if (!this->crypter->set_key(this->crypter,
chunk_create((uint8_t*)k, AKA_K_LEN)))
{
return FALSE;
}
/* XOR RAND and OPc */
memcpy(data, rand, sizeof(data));
memxor(data, opc, sizeof(data));
if (!this->crypter->encrypt(this->crypter, chunk_create(data, sizeof(data)),
chunk_create(iv, sizeof(iv)), &temp))
{
return FALSE;
}
/* to obtain output block OUT2: XOR OPc and TEMP,
* rotate by r2=0, and XOR on the constant c2 (which is all zeroes except
* that the last bit is 1). */
for (i = 0; i < 16; i++)
{
data[i] = temp.ptr[i] ^ opc[i];
}
data[15] ^= 1;
if (!this->crypter->encrypt(this->crypter, chunk_create(data, sizeof(data)),
chunk_create(iv, sizeof(iv)), NULL))
{
chunk_free(&temp);
return FALSE;
}
memxor(data, opc, sizeof(data));
/* f5 output */
memcpy(ak, data, 6);
/* f2 output */
memcpy(res, &data[8], 8);
/* to obtain output block OUT3: XOR OPc and TEMP,
* rotate by r3=32, and XOR on the constant c3 (which
* is all zeroes except that the next to last bit is 1) */
for (i = 0; i < 16; i++)
{
data[(i + 12) % 16] = temp.ptr[i] ^ opc[i];
}
data[15] ^= 2;
if (!this->crypter->encrypt(this->crypter, chunk_create(data, sizeof(data)),
chunk_create(iv, sizeof(iv)), NULL))
{
chunk_free(&temp);
return FALSE;
}
memxor(data, opc, sizeof(data));
/* f3 output */
memcpy(ck, data, 16);
/* to obtain output block OUT4: XOR OPc and TEMP,
* rotate by r4=64, and XOR on the constant c4 (which
* is all zeroes except that the 2nd from last bit is 1). */
for (i = 0; i < 16; i++)
{
data[(i + 8) % 16] = temp.ptr[i] ^ opc[i];
}
data[15] ^= 4;
if (!this->crypter->encrypt(this->crypter, chunk_create(data, sizeof(data)),
chunk_create(iv, sizeof(iv)), NULL))
{
chunk_free(&temp);
return FALSE;
}
memxor(data, opc, sizeof(data));
/* f4 output */
memcpy(ik, data, 16);
chunk_free(&temp);
return TRUE;
}
METHOD(eap_aka_3gpp_functions_t, f5star, bool,
private_eap_aka_3gpp_functions_t *this, const uint8_t k[AKA_K_LEN],
const uint8_t opc[AKA_OPC_LEN], const uint8_t rand[AKA_RAND_LEN],
uint8_t aks[AKA_AK_LEN])
{
uint8_t i, data[16], iv[16] = { 0 };
chunk_t temp;
if (!this->crypter->set_key(this->crypter,
chunk_create((uint8_t*)k, AKA_K_LEN)))
{
return FALSE;
}
/* XOR RAND and OPc */
memcpy(data, rand, sizeof(data));
memxor(data, opc, sizeof(data));
if (!this->crypter->encrypt(this->crypter, chunk_create(data, sizeof(data)),
chunk_create(iv, sizeof(iv)), &temp))
{
return FALSE;
}
/* to obtain output block OUT5: XOR OPc and the output above,
* rotate by r5=96, and XOR on the constant c5 (which
* is all zeroes except that the 3rd from last bit is 1). */
for (i = 0; i < 16; i++)
{
data[(i + 4) % 16] = temp.ptr[i] ^ opc[i];
}
data[15] ^= 8;
chunk_free(&temp);
if (!this->crypter->encrypt(this->crypter, chunk_create(data, sizeof(data)),
chunk_create(iv, sizeof(iv)), NULL))
{
return FALSE;
}
memxor(data, opc, sizeof(data));
memcpy(aks, data, 6);
return TRUE;
}
METHOD(eap_aka_3gpp_functions_t, destroy, void,
private_eap_aka_3gpp_functions_t *this)
{
this->crypter->destroy(this->crypter);
free(this);
}
/**
* See header
*/
eap_aka_3gpp_functions_t *eap_aka_3gpp_functions_create()
{
private_eap_aka_3gpp_functions_t *this;
INIT(this,
.public = {
.f1 = _f1,
.f1star = _f1star,
.f2345 = _f2345,
.f5star = _f5star,
.destroy = _destroy,
},
.crypter = lib->crypto->create_crypter(lib->crypto, ENCR_AES_CBC, 16),
);
if (!this->crypter)
{
DBG1(DBG_IKE, "%N not supported, unable to use 3GPP algorithm",
encryption_algorithm_names, ENCR_AES_CBC);
free(this);
return NULL;
}
return &this->public;
}