mirror of https://gerrit.osmocom.org/libosmocore
164 lines
3.6 KiB
C
164 lines
3.6 KiB
C
/*
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* (C) 2021 by sysmocom s.f.m.c. GmbH
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*
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* Author: Eric Wild <ewild@sysmocom.de>
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*
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* All Rights Reserved
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*
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* SPDX-License-Identifier: GPL-2.0+
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <stdint.h>
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#include <string.h>
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#include "config.h"
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#if (USE_GNUTLS)
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#include <gnutls/gnutls.h>
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#include <gnutls/crypto.h>
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#define HMAC_FUNC(k,lk,s,sl,out) gnutls_hmac_fast(GNUTLS_MAC_SHA256,k,lk,s,sl,out)
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#else
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#include <osmocom/crypt/kdf.h>
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#define HMAC_FUNC(k,lk,s,sl,out) hmac_sha256(k,lk,s,sl,out)
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#endif
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#include <osmocom/core/bit32gen.h>
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#include <osmocom/crypt/kdf.h>
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#include "kdf/common.h"
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#include "kdf/sha256.h"
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#if (USE_GNUTLS)
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/* gnutls < 3.3.0 requires global init.
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* gnutls >= 3.3.0 does it automatic.
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* It doesn't hurt calling it twice,
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* as long it's not done at the same time (threads).
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*/
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__attribute__((constructor))
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static void on_dso_load_gnutls(void)
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{
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if (!gnutls_check_version("3.3.0"))
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gnutls_global_init();
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}
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__attribute__((destructor))
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static void on_dso_unload_gnutls(void)
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{
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if (!gnutls_check_version("3.3.0"))
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gnutls_global_deinit();
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}
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#endif
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/*
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* This file uses the generic key derivation function defined in 3GPP TS 33.220 Annex B
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*
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* The S parameter always consists of concatenated values FC | P0 | L0 | Pi | Li | ...
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* with Pi = Parameter number i and Li = Length of Pi (two octets)
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*
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* FC is either a single octet or two octets 0xff | FC
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* FC values ranges depend on the specification parts that use the KDF,
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* they are defined in 3GPP TS 33.220 Annex B.2.2
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*
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*/
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/*! \addtogroup kdf
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* @{
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* key derivation functions
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*
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* \file kdf.c */
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/* 3GPP TS 33.102 B.5 */
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void osmo_kdf_kc128(const uint8_t* ck, const uint8_t* ik, uint8_t* kc128) {
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uint8_t k[16*2];
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uint8_t s[1];
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uint8_t out_tmp256[32];
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memcpy (&k[0], ck, 16);
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memcpy (&k[16], ik, 16);
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s[0] = 0x32; // yeah, really just one FC byte..
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HMAC_FUNC(k, 32, s, 1, out_tmp256);
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memcpy(kc128, out_tmp256, 16);
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}
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/* 3GPP TS 33.401 A.2 */
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void osmo_kdf_kasme(const uint8_t *ck, const uint8_t *ik, const uint8_t* plmn_id,
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const uint8_t *sqn, const uint8_t *ak, uint8_t *kasme)
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{
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uint8_t s[14];
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uint8_t k[16*2];
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int i;
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memcpy(&k[0], ck, 16);
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memcpy(&k[16], ik, 16);
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s[0] = 0x10;
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memcpy(&s[1], plmn_id, 3);
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s[4] = 0x00;
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s[5] = 0x03;
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for (i = 0; i < 6; i++)
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s[6+i] = sqn[i] ^ ak[i];
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s[12] = 0x00;
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s[13] = 0x06;
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HMAC_FUNC(k, 32, s, 14, kasme);
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}
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/* 3GPP TS 33.401 A.3 */
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void osmo_kdf_enb(const uint8_t *kasme, uint32_t ul_count, uint8_t *kenb)
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{
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uint8_t s[7];
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s[0] = 0x11;
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osmo_store32be(ul_count, &s[1]);
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s[5] = 0x00;
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s[6] = 0x04;
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HMAC_FUNC(kasme, 32, s, 7, kenb);
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}
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/* 3GPP TS 33.401 A.4 */
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void osmo_kdf_nh(const uint8_t *kasme, const uint8_t *sync_input, uint8_t *nh)
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{
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uint8_t s[35];
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s[0] = 0x12;
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memcpy(s+1, sync_input, 32);
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s[33] = 0x00;
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s[34] = 0x20;
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HMAC_FUNC(kasme, 32, s, 35, nh);
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}
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/* 3GPP TS 33.401 A.7 */
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void osmo_kdf_nas(uint8_t algo_type, uint8_t algo_id, const uint8_t *kasme, 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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s[0] = 0x15;
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s[1] = algo_type;
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s[2] = 0x00;
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s[3] = 0x01;
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s[4] = algo_id;
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s[5] = 0x00;
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s[6] = 0x01;
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HMAC_FUNC(kasme, 32, s, 7, out);
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memcpy(knas, out+16, 16);
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}
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/*! @} */
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