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openairinterface5g/openair2/UTIL/OSA/osa_key_deriver.c
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3.9 KiB
C

/*******************************************************************************
OpenAirInterface
Copyright(c) 1999 - 2014 Eurecom
OpenAirInterface 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 3 of the License, or
(at your option) any later version.
OpenAirInterface 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.
You should have received a copy of the GNU General Public License
along with OpenAirInterface.The full GNU General Public License is
included in this distribution in the file called "COPYING". If not,
see <http://www.gnu.org/licenses/>.
Contact Information
OpenAirInterface Admin: openair_admin@eurecom.fr
OpenAirInterface Tech : openair_tech@eurecom.fr
OpenAirInterface Dev : openair4g-devel@lists.eurecom.fr
Address : Eurecom, Campus SophiaTech, 450 Route des Chappes, CS 50193 - 06904 Biot Sophia Antipolis cedex, FRANCE
*******************************************************************************/
#include <stdint.h>
#include <nettle/hmac.h>
#include "osa_defs.h"
#include "osa_internal.h"
#include "UTIL/LOG/log.h"
static inline
void kdf(const uint8_t *s, const uint32_t s_length, const uint8_t *key,
const uint32_t key_length, uint8_t **out, uint32_t out_length)
{
struct hmac_sha256_ctx ctx;
uint8_t *buffer;
buffer = malloc(sizeof(uint8_t) * out_length);
hmac_sha256_set_key(&ctx, key_length, key);
hmac_sha256_update(&ctx, s_length, s);
hmac_sha256_digest(&ctx, out_length, buffer);
*out = buffer;
}
/*!
* @brief Derive the keys from key and perform truncate on the generated key to
* reduce his size to 128 bits. Definition of the derivation function can
* be found in 3GPP TS.33401 #A.7
* @param[in] alg_type Algorithm distinguisher
* @param[in] alg_id Algorithm identifier.
* Possible values are:
* - 0 for EIA0 algorithm (Null Integrity Protection algorithm)
* - 1 for 128-EIA1 SNOW 3G
* - 2 for 128-EIA2 AES
* @param[in] key The top key used to derive other subkeys
* @param[out] out Pointer to reference where output of KDF will be stored.
* NOTE: knas is dynamically allocated by the KDF function
*/
int derive_key(algorithm_type_dist_t alg_type, uint8_t alg_id,
const uint8_t key[32], uint8_t **out)
{
uint8_t string[7];
/* FC */
string[0] = FC_ALG_KEY_DER;
/* P0 = algorithm type distinguisher */
string[1] = (uint8_t)(alg_type & 0xFF);
/* L0 = length(P0) = 1 */
string[2] = 0x00;
string[3] = 0x01;
/* P1 */
string[4] = alg_id;
/* L1 = length(P1) = 1 */
string[5] = 0x00;
string[6] = 0x01;
#if defined(SECU_DEBUG)
{
int i;
char payload[6 * sizeof(string) + 1];
int index = 0;
for (i = 0; i < sizeof(string); i++)
index += sprintf(&payload[index], "0x%02x ", string[i]);
LOG_D(OSA, "Key deriver input string: %s\n", payload);
}
#endif
kdf(string, 7, key, 32, out, 32);
return 0;
}
/*
int derive_keNB(const uint8_t key[32], const uint32_t nas_count, uint8_t **keNB)
{
uint8_t string[7];
// FC
string[0] = FC_KENB;
// P0 = Uplink NAS count
string[1] = (nas_count & 0xff000000) >> 24;
string[2] = (nas_count & 0x00ff0000) >> 16;
string[3] = (nas_count & 0x0000ff00) >> 8;
string[4] = (nas_count & 0x000000ff);
// Length of NAS count
string[5] = 0x00;
string[6] = 0x04;
#if defined(SECU_DEBUG)
{
int i;
char payload[6 * sizeof(string) + 1];
int index = 0;
for (i = 0; i < sizeof(string); i++)
index += sprintf(&payload[index], "0x%02x ", string[i]);
LOG_D(OSA, "KeNB deriver input string: %s\n", payload);
}
#endif
kdf(string, 7, key, 32, keNB, 32);
return 0;
}
*/