/******************************************************************************* 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@eurecom.fr Address : Eurecom, Compus SophiaTech 450, route des chappes, 06451 Biot, 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; } */