Eric | c3fa007 | 2021-05-19 17:45:38 +0200 | [diff] [blame] | 1 | /* |
| 2 | * (C) 2021 by sysmocom s.f.m.c. GmbH |
| 3 | * |
| 4 | * Author: Eric Wild <ewild@sysmocom.de> |
| 5 | * |
| 6 | * All Rights Reserved |
| 7 | * |
| 8 | * SPDX-License-Identifier: GPL-2.0+ |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU General Public License as published by |
| 12 | * the Free Software Foundation; either version 2 of the License, or |
| 13 | * (at your option) any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | * GNU General Public License for more details. |
| 19 | * |
Eric | c3fa007 | 2021-05-19 17:45:38 +0200 | [diff] [blame] | 20 | */ |
| 21 | |
| 22 | #include <stdint.h> |
| 23 | #include <string.h> |
| 24 | |
Pau Espin Pedrol | 88955fb | 2023-01-18 18:54:00 +0100 | [diff] [blame] | 25 | #include "config.h" |
Eric | c3fa007 | 2021-05-19 17:45:38 +0200 | [diff] [blame] | 26 | #if (USE_GNUTLS) |
| 27 | #include <gnutls/gnutls.h> |
| 28 | #include <gnutls/crypto.h> |
| 29 | #define HMAC_FUNC(k,lk,s,sl,out) gnutls_hmac_fast(GNUTLS_MAC_SHA256,k,lk,s,sl,out) |
| 30 | #else |
| 31 | #include <osmocom/crypt/kdf.h> |
| 32 | #define HMAC_FUNC(k,lk,s,sl,out) hmac_sha256(k,lk,s,sl,out) |
| 33 | #endif |
| 34 | |
| 35 | #include <osmocom/core/bit32gen.h> |
| 36 | #include <osmocom/crypt/kdf.h> |
| 37 | |
| 38 | #include "kdf/common.h" |
| 39 | #include "kdf/sha256.h" |
| 40 | |
| 41 | |
| 42 | #if (USE_GNUTLS) |
| 43 | /* gnutls < 3.3.0 requires global init. |
| 44 | * gnutls >= 3.3.0 does it automatic. |
| 45 | * It doesn't hurt calling it twice, |
| 46 | * as long it's not done at the same time (threads). |
| 47 | */ |
| 48 | __attribute__((constructor)) |
| 49 | static void on_dso_load_gnutls(void) |
| 50 | { |
| 51 | if (!gnutls_check_version("3.3.0")) |
| 52 | gnutls_global_init(); |
| 53 | } |
| 54 | |
| 55 | __attribute__((destructor)) |
| 56 | static void on_dso_unload_gnutls(void) |
| 57 | { |
| 58 | if (!gnutls_check_version("3.3.0")) |
| 59 | gnutls_global_deinit(); |
| 60 | } |
| 61 | #endif |
| 62 | |
| 63 | /* |
| 64 | * This file uses the generic key derivation function defined in 3GPP TS 33.220 Annex B |
| 65 | * |
| 66 | * The S parameter always consists of concatenated values FC | P0 | L0 | Pi | Li | ... |
| 67 | * with Pi = Parameter number i and Li = Length of Pi (two octets) |
| 68 | * |
| 69 | * FC is either a single octet or two octets 0xff | FC |
| 70 | * FC values ranges depend on the specification parts that use the KDF, |
| 71 | * they are defined in 3GPP TS 33.220 Annex B.2.2 |
| 72 | * |
| 73 | */ |
| 74 | |
| 75 | /*! \addtogroup kdf |
| 76 | * @{ |
| 77 | * key derivation functions |
| 78 | * |
| 79 | * \file kdf.c */ |
| 80 | |
| 81 | /* 3GPP TS 33.102 B.5 */ |
| 82 | void osmo_kdf_kc128(const uint8_t* ck, const uint8_t* ik, uint8_t* kc128) { |
| 83 | uint8_t k[16*2]; |
| 84 | uint8_t s[1]; |
| 85 | uint8_t out_tmp256[32]; |
| 86 | memcpy (&k[0], ck, 16); |
| 87 | memcpy (&k[16], ik, 16); |
| 88 | |
| 89 | s[0] = 0x32; // yeah, really just one FC byte.. |
| 90 | |
| 91 | HMAC_FUNC(k, 32, s, 1, out_tmp256); |
| 92 | memcpy(kc128, out_tmp256, 16); |
| 93 | } |
| 94 | |
| 95 | /* 3GPP TS 33.401 A.2 */ |
| 96 | void osmo_kdf_kasme(const uint8_t *ck, const uint8_t *ik, const uint8_t* plmn_id, |
| 97 | const uint8_t *sqn, const uint8_t *ak, uint8_t *kasme) |
| 98 | { |
| 99 | uint8_t s[14]; |
| 100 | uint8_t k[16*2]; |
| 101 | int i; |
| 102 | |
| 103 | memcpy(&k[0], ck, 16); |
| 104 | memcpy(&k[16], ik, 16); |
| 105 | |
| 106 | s[0] = 0x10; |
| 107 | memcpy(&s[1], plmn_id, 3); |
| 108 | s[4] = 0x00; |
| 109 | s[5] = 0x03; |
| 110 | |
| 111 | for (i = 0; i < 6; i++) |
| 112 | s[6+i] = sqn[i] ^ ak[i]; |
| 113 | s[12] = 0x00; |
| 114 | s[13] = 0x06; |
| 115 | |
| 116 | HMAC_FUNC(k, 32, s, 14, kasme); |
| 117 | } |
| 118 | |
| 119 | /* 3GPP TS 33.401 A.3 */ |
| 120 | void osmo_kdf_enb(const uint8_t *kasme, uint32_t ul_count, uint8_t *kenb) |
| 121 | { |
| 122 | uint8_t s[7]; |
| 123 | |
| 124 | s[0] = 0x11; |
| 125 | osmo_store32be(ul_count, &s[1]); |
| 126 | s[5] = 0x00; |
| 127 | s[6] = 0x04; |
| 128 | |
| 129 | HMAC_FUNC(kasme, 32, s, 7, kenb); |
| 130 | } |
| 131 | |
| 132 | /* 3GPP TS 33.401 A.4 */ |
| 133 | void osmo_kdf_nh(const uint8_t *kasme, const uint8_t *sync_input, uint8_t *nh) |
| 134 | { |
| 135 | uint8_t s[35]; |
| 136 | |
| 137 | s[0] = 0x12; |
| 138 | memcpy(s+1, sync_input, 32); |
| 139 | s[33] = 0x00; |
| 140 | s[34] = 0x20; |
| 141 | |
| 142 | HMAC_FUNC(kasme, 32, s, 35, nh); |
| 143 | } |
| 144 | |
| 145 | /* 3GPP TS 33.401 A.7 */ |
| 146 | void osmo_kdf_nas(uint8_t algo_type, uint8_t algo_id, const uint8_t *kasme, uint8_t *knas) |
| 147 | { |
| 148 | uint8_t s[7]; |
| 149 | uint8_t out[32]; |
| 150 | |
| 151 | s[0] = 0x15; |
| 152 | s[1] = algo_type; |
| 153 | s[2] = 0x00; |
| 154 | s[3] = 0x01; |
| 155 | s[4] = algo_id; |
| 156 | s[5] = 0x00; |
| 157 | s[6] = 0x01; |
| 158 | |
| 159 | HMAC_FUNC(kasme, 32, s, 7, out); |
| 160 | memcpy(knas, out+16, 16); |
| 161 | } |
| 162 | |
| 163 | /*! @} */ |