Harald Welte | 8bd9d5d | 2023-05-28 09:36:50 +0200 | [diff] [blame] | 1 | /* (C) 2023 by Harald Welte <laforge@osmocom.org> |
| 2 | * |
| 3 | * All Rights Reserved |
| 4 | * |
| 5 | * SPDX-License-Identifier: GPL-2.0+ |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | */ |
| 17 | |
| 18 | #include <stdint.h> |
| 19 | #include <string.h> |
| 20 | #include <string.h> |
| 21 | #include <errno.h> |
| 22 | |
| 23 | #include <osmocom/core/utils.h> |
| 24 | |
| 25 | #include "KeccakP-1600-3gpp.h" |
| 26 | |
| 27 | /* TUAK authentication algorithm |
| 28 | * as proposed by 3GPP as an alternative to Milenage |
| 29 | * algorithm based on SHA-3 (more exactly its KeccakP-1600 permutation) |
| 30 | * see 3GPP TS 35.231, 232 and 233 */ |
| 31 | |
| 32 | static unsigned int g_keccak_iterations = 1; |
| 33 | static const char algoname[] = "TUAK1.0"; |
| 34 | const uint8_t zero16[16] = { 0, }; |
| 35 | |
| 36 | void tuak_set_keccak_iterations(unsigned int i) |
| 37 | { |
| 38 | g_keccak_iterations = i; |
| 39 | } |
| 40 | |
| 41 | /* append data from 'input' to 'buf' at 'idx', reversing byte order */ |
| 42 | #define PUSH_DATA(buf, idx, input, nbytes) \ |
| 43 | for (int i = nbytes-1; i >= 0; i--) { \ |
| 44 | buf[idx++] = input[i]; \ |
| 45 | } |
| 46 | |
| 47 | /* like memcpy(), but reversing they order of bytes */ |
| 48 | void memcpy_reverse(uint8_t *dst, const uint8_t *src, size_t len) |
| 49 | { |
| 50 | for (size_t i = 0; i < len; i++) |
| 51 | dst[i] = src[len-i-1]; |
| 52 | } |
| 53 | |
| 54 | static void tuak_core(uint8_t buf[200], const uint8_t *opc, uint8_t instance, const uint8_t *_rand, |
| 55 | const uint8_t *amf, const uint8_t *sqn, const uint8_t *k, uint8_t k_len_bytes, |
| 56 | unsigned int keccac_iterations) |
| 57 | { |
| 58 | unsigned int idx = 0; |
| 59 | |
| 60 | PUSH_DATA(buf, idx, opc, 32); |
| 61 | buf[idx++] = instance; |
| 62 | PUSH_DATA(buf, idx, algoname, strlen(algoname)); /* without trailing NUL */ |
| 63 | PUSH_DATA(buf, idx, _rand, 16); |
| 64 | PUSH_DATA(buf, idx, amf, 2); |
| 65 | PUSH_DATA(buf, idx, sqn, 6); |
| 66 | PUSH_DATA(buf, idx, k, k_len_bytes); |
| 67 | memset(buf+idx, 0, 32-k_len_bytes); idx += 32-k_len_bytes; |
| 68 | buf[idx++] = 0x1f; |
| 69 | memset(buf+idx, 0, 38); idx += 38; |
| 70 | buf[idx++] = 0x80; |
| 71 | memset(buf+idx, 0, 64); idx += 64; |
| 72 | OSMO_ASSERT(idx == 200); |
| 73 | |
| 74 | for (unsigned int i = 0; i < keccac_iterations; i++) |
| 75 | Keccak_f_64((uint64_t *) buf); |
| 76 | } |
| 77 | |
| 78 | /** |
| 79 | * tuak_f1 - TUAK f1 algorithm |
| 80 | * @opc: OPc = 256-bit value derived from OP and K |
| 81 | * @k: K = 128-bit or 256-bit subscriber key |
| 82 | * @_rand: RAND = 128-bit random challenge |
| 83 | * @sqn: SQN = 48-bit sequence number |
| 84 | * @amf: AMF = 16-bit authentication management field |
| 85 | * @mac_a: Buffer for MAC-A = 64/128/256-bit network authentication code |
| 86 | * Returns: 0 on success, -1 on failure |
| 87 | */ |
| 88 | int tuak_f1(const uint8_t *opc, const uint8_t *k, uint8_t k_len_bytes, const uint8_t *_rand, |
| 89 | const uint8_t *sqn, const uint8_t *amf, uint8_t *mac_a, uint8_t mac_a_len_bytes, |
| 90 | unsigned int keccac_iterations) |
| 91 | { |
| 92 | uint8_t buf[200]; |
| 93 | uint8_t instance = 0x00; |
| 94 | |
| 95 | switch (mac_a_len_bytes) { |
| 96 | case 8: |
| 97 | instance |= 0x08; |
| 98 | break; |
| 99 | case 16: |
| 100 | instance |= 0x10; |
| 101 | break; |
| 102 | case 32: |
| 103 | instance |= 0x20; |
| 104 | break; |
| 105 | default: |
| 106 | return -EINVAL; |
| 107 | } |
| 108 | |
| 109 | switch (k_len_bytes) { |
| 110 | case 16: |
| 111 | break; |
| 112 | case 32: |
| 113 | instance |= 0x01; |
| 114 | break; |
| 115 | default: |
| 116 | return -EINVAL; |
| 117 | } |
| 118 | |
| 119 | tuak_core(buf, opc, instance, _rand, amf, sqn, k, k_len_bytes, keccac_iterations); |
| 120 | |
| 121 | memcpy_reverse(mac_a, buf, mac_a_len_bytes); |
| 122 | |
| 123 | return 0; |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * tuak_f1star - TUAK f1* algorithm |
| 128 | * @opc: OPc = 256-bit value derived from OP and K |
| 129 | * @k: K = 128-bit or 256-bit subscriber key |
| 130 | * @_rand: RAND = 128-bit random challenge |
| 131 | * @sqn: SQN = 48-bit sequence number |
| 132 | * @amf: AMF = 16-bit authentication management field |
| 133 | * @mac_s: Buffer for MAC-S = 64/128/256-bit resync authentication code |
| 134 | * Returns: 0 on success, -1 on failure |
| 135 | */ |
| 136 | int tuak_f1star(const uint8_t *opc, const uint8_t *k, uint8_t k_len_bytes, const uint8_t *_rand, |
| 137 | const uint8_t *sqn, const uint8_t *amf, uint8_t *mac_s, uint8_t mac_s_len_bytes, |
| 138 | unsigned int keccac_iterations) |
| 139 | { |
| 140 | uint8_t buf[200]; |
| 141 | uint8_t instance = 0x80; |
| 142 | |
| 143 | switch (mac_s_len_bytes) { |
| 144 | case 8: |
| 145 | instance |= 0x08; |
| 146 | break; |
| 147 | case 16: |
| 148 | instance |= 0x10; |
| 149 | break; |
| 150 | case 32: |
| 151 | instance |= 0x20; |
| 152 | break; |
| 153 | default: |
| 154 | return -EINVAL; |
| 155 | } |
| 156 | |
| 157 | switch (k_len_bytes) { |
| 158 | case 16: |
| 159 | break; |
| 160 | case 32: |
| 161 | instance |= 0x01; |
| 162 | break; |
| 163 | default: |
| 164 | return -EINVAL; |
| 165 | } |
| 166 | |
| 167 | tuak_core(buf, opc, instance, _rand, amf, sqn, k, k_len_bytes, keccac_iterations); |
| 168 | |
| 169 | memcpy_reverse(mac_s, buf, mac_s_len_bytes); |
| 170 | |
| 171 | return 0; |
| 172 | } |
| 173 | |
| 174 | /** |
| 175 | * tuak_f2345 - TUAK f2, f3, f4, f5, algorithms |
| 176 | * @opc: OPc = 256-bit value derived from OP and K |
| 177 | * @k: K = 128/256-bit subscriber key |
| 178 | * @_rand: RAND = 128-bit random challenge |
| 179 | * @res: Buffer for RES = 32/64/128/256-bit signed response (f2), or %NULL |
| 180 | * @ck: Buffer for CK = 128/256-bit confidentiality key (f3), or %NULL |
| 181 | * @ik: Buffer for IK = 128/256-bit integrity key (f4), or %NULL |
| 182 | * @ak: Buffer for AK = 48-bit anonymity key (f5), or %NULL |
| 183 | * Returns: 0 on success, -1 on failure |
| 184 | */ |
| 185 | int tuak_f2345(const uint8_t *opc, const uint8_t *k, uint8_t k_len_bytes, |
| 186 | const uint8_t *_rand, uint8_t *res, uint8_t res_len_bytes, |
| 187 | uint8_t *ck, uint8_t ck_len_bytes, |
| 188 | uint8_t *ik, uint8_t ik_len_bytes, uint8_t *ak, unsigned int keccac_iterations) |
| 189 | { |
| 190 | uint8_t buf[200]; |
| 191 | uint8_t instance = 0x40; |
| 192 | |
| 193 | switch (res_len_bytes) { |
| 194 | case 4: |
| 195 | break; |
| 196 | case 8: |
| 197 | instance |= 0x08; |
| 198 | break; |
| 199 | case 16: |
| 200 | instance |= 0x10; |
| 201 | break; |
| 202 | case 32: |
| 203 | instance |= 0x20; |
| 204 | break; |
| 205 | default: |
| 206 | return -EINVAL; |
| 207 | } |
| 208 | |
| 209 | switch (ck_len_bytes) { |
| 210 | case 16: |
| 211 | break; |
| 212 | case 32: |
| 213 | instance |= 0x04; |
| 214 | break; |
| 215 | default: |
| 216 | return -EINVAL; |
| 217 | } |
| 218 | |
| 219 | switch (ik_len_bytes) { |
| 220 | case 16: |
| 221 | break; |
| 222 | case 32: |
| 223 | instance |= 0x02; |
| 224 | break; |
| 225 | default: |
| 226 | return -EINVAL; |
| 227 | } |
| 228 | |
| 229 | switch (k_len_bytes) { |
| 230 | case 16: |
| 231 | break; |
| 232 | case 32: |
| 233 | instance |= 0x01; |
| 234 | break; |
| 235 | default: |
| 236 | return -EINVAL; |
| 237 | } |
| 238 | |
| 239 | tuak_core(buf, opc, instance, _rand, zero16, zero16, k, k_len_bytes, keccac_iterations); |
| 240 | |
| 241 | if (res) |
| 242 | memcpy_reverse(res, buf, res_len_bytes); |
| 243 | |
| 244 | if (ck) |
| 245 | memcpy_reverse(ck, buf + 32, ck_len_bytes); |
| 246 | |
| 247 | if (ik) |
| 248 | memcpy_reverse(ik, buf + 64, ik_len_bytes); |
| 249 | |
| 250 | if (ak) |
| 251 | memcpy_reverse(ak, buf + 96, 6); |
| 252 | |
| 253 | return 0; |
| 254 | } |
| 255 | |
| 256 | /** |
| 257 | * tuak_f5star - TUAK f5* algorithm |
| 258 | * @opc: OPc = 256-bit value derived from OP and K |
| 259 | * @k: K = 128/256-bit subscriber key |
| 260 | * @_rand: RAND = 128-bit random challenge |
| 261 | * @ak: Buffer for AK = 48-bit anonymity key (f5) |
| 262 | * Returns: 0 on success, -1 on failure |
| 263 | */ |
| 264 | int tuak_f5star(const uint8_t *opc, const uint8_t *k, uint8_t k_len_bytes, |
| 265 | const uint8_t *_rand, uint8_t *ak, unsigned int keccac_iterations) |
| 266 | { |
| 267 | uint8_t buf[200]; |
| 268 | uint8_t instance = 0xc0; |
| 269 | |
| 270 | switch (k_len_bytes) { |
| 271 | case 16: |
| 272 | break; |
| 273 | case 32: |
| 274 | instance += 1; |
| 275 | break; |
| 276 | default: |
| 277 | return -EINVAL; |
| 278 | } |
| 279 | |
| 280 | tuak_core(buf, opc, instance, _rand, zero16, zero16, k, k_len_bytes, keccac_iterations); |
| 281 | |
| 282 | memcpy_reverse(ak, buf + 96, 6); |
| 283 | |
| 284 | return 0; |
| 285 | } |
| 286 | |
| 287 | /** |
| 288 | * tuak_generate - Generate AKA AUTN,IK,CK,RES |
| 289 | * @opc: OPc = 256-bit operator variant algorithm configuration field (encr.) |
| 290 | * @amf: AMF = 16-bit authentication management field |
| 291 | * @k: K = 128/256-bit subscriber key |
| 292 | * @sqn: SQN = 48-bit sequence number |
| 293 | * @_rand: RAND = 128-bit random challenge |
| 294 | * @autn: Buffer for AUTN = 128-bit authentication token |
| 295 | * @ik: Buffer for IK = 128/256-bit integrity key (f4), or %NULL |
| 296 | * @ck: Buffer for CK = 128/256-bit confidentiality key (f3), or %NULL |
| 297 | * @res: Buffer for RES = 32/64/128-bit signed response (f2), or %NULL |
| 298 | * @res_len: Max length for res; set to used length or 0 on failure |
| 299 | */ |
| 300 | void tuak_generate(const uint8_t *opc, const uint8_t *amf, const uint8_t *k, uint8_t k_len_bytes, |
| 301 | const uint8_t *sqn, const uint8_t *_rand, uint8_t *autn, uint8_t *ik, |
| 302 | uint8_t *ck, uint8_t *res, size_t *res_len) |
| 303 | { |
| 304 | int i; |
| 305 | uint8_t mac_a[8], ak[6]; |
| 306 | |
| 307 | if (*res_len < 4) { |
| 308 | *res_len = 0; |
| 309 | return; |
| 310 | } |
| 311 | if (tuak_f1(opc, k, k_len_bytes, _rand, sqn, amf, mac_a, sizeof(mac_a), g_keccak_iterations) || |
| 312 | tuak_f2345(opc, k, k_len_bytes, _rand, res, *res_len, ck, 16, ik, 16, ak, g_keccak_iterations)) { |
| 313 | *res_len = 0; |
| 314 | return; |
| 315 | } |
| 316 | |
| 317 | /* AUTN = (SQN ^ AK) || AMF || MAC */ |
| 318 | for (i = 0; i < 6; i++) |
| 319 | autn[i] = sqn[i] ^ ak[i]; |
| 320 | memcpy(autn + 6, amf, 2); |
| 321 | memcpy(autn + 8, mac_a, 8); |
| 322 | } |
| 323 | |
| 324 | |
| 325 | /** |
| 326 | * tuak_auts - Milenage AUTS validation |
| 327 | * @opc: OPc = 256-bit operator variant algorithm configuration field (encr.) |
| 328 | * @k: K = 128/256-bit subscriber key |
| 329 | * @_rand: RAND = 128-bit random challenge |
| 330 | * @auts: AUTS = 112-bit authentication token from client |
| 331 | * @sqn: Buffer for SQN = 48-bit sequence number |
| 332 | * Returns: 0 = success (sqn filled), -1 on failure |
| 333 | */ |
| 334 | int tuak_auts(const uint8_t *opc, const uint8_t *k, uint8_t k_len_bytes, |
| 335 | const uint8_t *_rand, const uint8_t *auts, uint8_t *sqn) |
| 336 | { |
| 337 | uint8_t amf[2] = { 0x00, 0x00 }; /* TS 33.102 v7.0.0, 6.3.3 */ |
| 338 | uint8_t ak[6], mac_s[8]; |
| 339 | int i; |
| 340 | |
| 341 | if (tuak_f5star(opc, k, k_len_bytes, _rand, ak, g_keccak_iterations)) |
| 342 | return -1; |
| 343 | for (i = 0; i < 6; i++) |
| 344 | sqn[i] = auts[i] ^ ak[i]; |
| 345 | if (tuak_f1star(opc, k, k_len_bytes, _rand, sqn, amf, mac_s, 8, g_keccak_iterations) || |
| 346 | memcmp(mac_s, auts + 6, 8) != 0) |
| 347 | return -1; |
| 348 | return 0; |
| 349 | } |
| 350 | |
| 351 | int tuak_opc_gen(uint8_t *opc, const uint8_t *k, uint8_t k_len_bytes, const uint8_t *op) |
| 352 | { |
| 353 | uint8_t buf[200]; |
| 354 | uint8_t instance; |
| 355 | |
| 356 | switch (k_len_bytes) { |
| 357 | case 16: |
| 358 | instance = 0x00; |
| 359 | break; |
| 360 | case 32: |
| 361 | instance = 0x01; |
| 362 | break; |
| 363 | default: |
| 364 | return -EINVAL; |
| 365 | } |
| 366 | |
| 367 | tuak_core(buf, op, instance, zero16, zero16, zero16, k, k_len_bytes, g_keccak_iterations); |
| 368 | |
| 369 | memcpy_reverse(opc, buf, 32); |
| 370 | |
| 371 | return 0; |
| 372 | } |