106 lines
3.3 KiB
C
106 lines
3.3 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 <stdint.h>
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#include <string.h>
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#include <nettle/hmac.h>
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#include "security_types.h"
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#include "secu_defs.h"
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void kdf(const uint8_t *key, uint16_t key_len, uint8_t *s, uint16_t s_len, uint8_t *out,
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uint16_t out_len)
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{
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struct hmac_sha256_ctx ctx;
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memset(&ctx, 0, sizeof(ctx));
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hmac_sha256_set_key(&ctx, key_len, key);
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hmac_sha256_update(&ctx, s_len, s);
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hmac_sha256_digest(&ctx, out_len, out);
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}
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#ifndef NAS_UE
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int derive_keNB(const uint8_t kasme[32], const uint32_t nas_count, uint8_t *keNB)
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{
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uint8_t s[7];
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// FC
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s[0] = FC_KENB;
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// P0 = Uplink NAS count
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s[1] = (nas_count & 0xff000000) >> 24;
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s[2] = (nas_count & 0x00ff0000) >> 16;
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s[3] = (nas_count & 0x0000ff00) >> 8;
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s[4] = (nas_count & 0x000000ff);
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// Length of NAS count
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s[5] = 0x00;
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s[6] = 0x04;
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kdf(kasme, 32, s, 7, keNB, 32);
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return 0;
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}
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#endif
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int derive_keNB_star(
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const uint8_t *kenb_32,
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const uint16_t pci,
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const uint32_t earfcn_dl,
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const bool is_rel8_only,
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uint8_t *kenb_star)
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{
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// see 33.401 section A.5 KeNB* derivation function
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uint8_t s[10] = {0};
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// FC = 0x13
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s[0] = FC_KENB_STAR;
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// P0 = PCI (target physical cell id)
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s[1] = (pci & 0x0000ff00) >> 8;
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s[2] = (pci & 0x000000ff);
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// L0 = length of PCI (i.e. 0x00 0x02)
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s[3] = 0x00;
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s[4] = 0x02;
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// P1 = EARFCN-DL (target physical cell downlink frequency)
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if (is_rel8_only) {
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s[5] = (earfcn_dl & 0x0000ff00) >> 8;
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s[6] = (earfcn_dl & 0x000000ff);
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s[7] = 0x00;
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s[8] = 0x02;
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kdf (kenb_32, 32, s, 9, kenb_star, 32);
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} else {
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s[5] = (earfcn_dl & 0x00ff0000) >> 16;
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s[6] = (earfcn_dl & 0x0000ff00) >> 8;
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s[7] = (earfcn_dl & 0x000000ff);
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s[8] = 0x00;
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s[9] = 0x03;
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kdf (kenb_32, 32, s, 10, kenb_star, 32);
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}
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// L1 length of EARFCN-DL (i.e. L1 = 0x00 0x02 if EARFCN-DL is between 0 and 65535, and L1 = 0x00 0x03 if EARFCN-DL is between 65536 and 262143)
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// NOTE: The length of EARFCN-DL cannot be generally set to 3 bytes for backward compatibility reasons: A Rel-8
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// entity (UE or eNB) would always assume an input parameter length of 2 bytes for the EARFCN-DL. This
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// would lead to different derived keys if another entity assumed an input parameter length of 3 bytes for the
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// EARFCN-DL.
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return 0;
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}
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