88 lines
2.6 KiB
C
88 lines
2.6 KiB
C
/*
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* Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The OpenAirInterface Software Alliance licenses this file to You under
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* the OAI Public License, Version 1.1 (the "License"); you may not use this file
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* except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.openairinterface.org/?page_id=698
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*-------------------------------------------------------------------------------
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* For more information about the OpenAirInterface (OAI) Software Alliance:
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* contact@openairinterface.org
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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#include "security_types.h"
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#include "secu_defs.h"
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#define SECU_DEBUG 1
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/*!
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* @brief Derive the kNASenc from kasme and perform truncate on the generated key to
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* reduce his size to 128 bits. Definition of the derivation function can
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* be found in 3GPP TS.33401 #A.7
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* @param[in] nas_alg_type NAS algorithm distinguisher
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* @param[in] nas_enc_alg_id NAS encryption/integrity algorithm identifier.
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* Possible values are:
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* - 0 for EIA0 algorithm (Null Integrity Protection algorithm)
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* - 1 for 128-EIA1 SNOW 3G
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* - 2 for 128-EIA2 AES
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* @param[in] kasme Key for MME as provided by AUC
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* @param[out] knas Pointer to reference where output of KDF will be stored.
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* NOTE: knas is dynamically allocated by the KDF function
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*/
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int derive_key_nas(algorithm_type_dist_t nas_alg_type, uint8_t nas_enc_alg_id,
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const uint8_t kasme[32], uint8_t *knas)
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{
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uint8_t s[7];
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uint8_t out[32];
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#if defined(SECU_DEBUG)
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int i;
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#endif
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/* FC */
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s[0] = FC_ALG_KEY_DER;
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/* P0 = algorithm type distinguisher */
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s[1] = (uint8_t)(nas_alg_type & 0xFF);
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/* L0 = length(P0) = 1 */
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s[2] = 0x00;
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s[3] = 0x01;
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/* P1 */
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s[4] = nas_enc_alg_id;
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/* L1 = length(P1) = 1 */
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s[5] = 0x00;
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s[6] = 0x01;
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#if defined(SECU_DEBUG)
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printf("%s FC %d nas_alg_type distinguisher %d nas_enc_alg_identity %d\n",
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__FUNCTION__, FC_ALG_KEY_DER, nas_alg_type, nas_enc_alg_id);
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for (i = 0; i < 7; i ++) {
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printf("0x%02x ", s[i]);
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}
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printf("\n");
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#endif
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kdf(kasme, 32, s, 7, out, 32);
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memcpy(knas, &out[31-16+1], 16);
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return 0;
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}
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