| /* (C) 2023 by Harald Welte <laforge@osmocom.org> |
| * |
| * All Rights Reserved |
| * |
| * SPDX-License-Identifier: GPL-2.0+ |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| */ |
| |
| #include <stdint.h> |
| #include <string.h> |
| #include <string.h> |
| #include <errno.h> |
| |
| #include <osmocom/core/utils.h> |
| |
| #include "KeccakP-1600-3gpp.h" |
| |
| /* TUAK authentication algorithm |
| * as proposed by 3GPP as an alternative to Milenage |
| * algorithm based on SHA-3 (more exactly its KeccakP-1600 permutation) |
| * see 3GPP TS 35.231, 232 and 233 */ |
| |
| static unsigned int g_keccak_iterations = 1; |
| static const char algoname[] = "TUAK1.0"; |
| const uint8_t zero16[16] = { 0, }; |
| |
| void tuak_set_keccak_iterations(unsigned int i) |
| { |
| g_keccak_iterations = i; |
| } |
| |
| /* append data from 'input' to 'buf' at 'idx', reversing byte order */ |
| #define PUSH_DATA(buf, idx, input, nbytes) \ |
| for (int i = nbytes-1; i >= 0; i--) { \ |
| buf[idx++] = input[i]; \ |
| } |
| |
| /* like memcpy(), but reversing they order of bytes */ |
| void memcpy_reverse(uint8_t *dst, const uint8_t *src, size_t len) |
| { |
| for (size_t i = 0; i < len; i++) |
| dst[i] = src[len-i-1]; |
| } |
| |
| static void tuak_core(uint8_t buf[200], const uint8_t *opc, uint8_t instance, const uint8_t *_rand, |
| const uint8_t *amf, const uint8_t *sqn, const uint8_t *k, uint8_t k_len_bytes, |
| unsigned int keccac_iterations) |
| { |
| unsigned int idx = 0; |
| |
| PUSH_DATA(buf, idx, opc, 32); |
| buf[idx++] = instance; |
| PUSH_DATA(buf, idx, algoname, strlen(algoname)); /* without trailing NUL */ |
| PUSH_DATA(buf, idx, _rand, 16); |
| PUSH_DATA(buf, idx, amf, 2); |
| PUSH_DATA(buf, idx, sqn, 6); |
| PUSH_DATA(buf, idx, k, k_len_bytes); |
| memset(buf+idx, 0, 32-k_len_bytes); idx += 32-k_len_bytes; |
| buf[idx++] = 0x1f; |
| memset(buf+idx, 0, 38); idx += 38; |
| buf[idx++] = 0x80; |
| memset(buf+idx, 0, 64); idx += 64; |
| OSMO_ASSERT(idx == 200); |
| |
| for (unsigned int i = 0; i < keccac_iterations; i++) |
| Keccak_f_64((uint64_t *) buf); |
| } |
| |
| /** |
| * tuak_f1 - TUAK f1 algorithm |
| * @opc: OPc = 256-bit value derived from OP and K |
| * @k: K = 128-bit or 256-bit subscriber key |
| * @_rand: RAND = 128-bit random challenge |
| * @sqn: SQN = 48-bit sequence number |
| * @amf: AMF = 16-bit authentication management field |
| * @mac_a: Buffer for MAC-A = 64/128/256-bit network authentication code |
| * Returns: 0 on success, -1 on failure |
| */ |
| int tuak_f1(const uint8_t *opc, const uint8_t *k, uint8_t k_len_bytes, const uint8_t *_rand, |
| const uint8_t *sqn, const uint8_t *amf, uint8_t *mac_a, uint8_t mac_a_len_bytes, |
| unsigned int keccac_iterations) |
| { |
| uint8_t buf[200]; |
| uint8_t instance = 0x00; |
| |
| switch (mac_a_len_bytes) { |
| case 8: |
| instance |= 0x08; |
| break; |
| case 16: |
| instance |= 0x10; |
| break; |
| case 32: |
| instance |= 0x20; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| switch (k_len_bytes) { |
| case 16: |
| break; |
| case 32: |
| instance |= 0x01; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| tuak_core(buf, opc, instance, _rand, amf, sqn, k, k_len_bytes, keccac_iterations); |
| |
| memcpy_reverse(mac_a, buf, mac_a_len_bytes); |
| |
| return 0; |
| } |
| |
| /** |
| * tuak_f1star - TUAK f1* algorithm |
| * @opc: OPc = 256-bit value derived from OP and K |
| * @k: K = 128-bit or 256-bit subscriber key |
| * @_rand: RAND = 128-bit random challenge |
| * @sqn: SQN = 48-bit sequence number |
| * @amf: AMF = 16-bit authentication management field |
| * @mac_s: Buffer for MAC-S = 64/128/256-bit resync authentication code |
| * Returns: 0 on success, -1 on failure |
| */ |
| int tuak_f1star(const uint8_t *opc, const uint8_t *k, uint8_t k_len_bytes, const uint8_t *_rand, |
| const uint8_t *sqn, const uint8_t *amf, uint8_t *mac_s, uint8_t mac_s_len_bytes, |
| unsigned int keccac_iterations) |
| { |
| uint8_t buf[200]; |
| uint8_t instance = 0x80; |
| |
| switch (mac_s_len_bytes) { |
| case 8: |
| instance |= 0x08; |
| break; |
| case 16: |
| instance |= 0x10; |
| break; |
| case 32: |
| instance |= 0x20; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| switch (k_len_bytes) { |
| case 16: |
| break; |
| case 32: |
| instance |= 0x01; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| tuak_core(buf, opc, instance, _rand, amf, sqn, k, k_len_bytes, keccac_iterations); |
| |
| memcpy_reverse(mac_s, buf, mac_s_len_bytes); |
| |
| return 0; |
| } |
| |
| /** |
| * tuak_f2345 - TUAK f2, f3, f4, f5, algorithms |
| * @opc: OPc = 256-bit value derived from OP and K |
| * @k: K = 128/256-bit subscriber key |
| * @_rand: RAND = 128-bit random challenge |
| * @res: Buffer for RES = 32/64/128/256-bit signed response (f2), or %NULL |
| * @ck: Buffer for CK = 128/256-bit confidentiality key (f3), or %NULL |
| * @ik: Buffer for IK = 128/256-bit integrity key (f4), or %NULL |
| * @ak: Buffer for AK = 48-bit anonymity key (f5), or %NULL |
| * Returns: 0 on success, -1 on failure |
| */ |
| int tuak_f2345(const uint8_t *opc, const uint8_t *k, uint8_t k_len_bytes, |
| const uint8_t *_rand, uint8_t *res, uint8_t res_len_bytes, |
| uint8_t *ck, uint8_t ck_len_bytes, |
| uint8_t *ik, uint8_t ik_len_bytes, uint8_t *ak, unsigned int keccac_iterations) |
| { |
| uint8_t buf[200]; |
| uint8_t instance = 0x40; |
| |
| switch (res_len_bytes) { |
| case 4: |
| break; |
| case 8: |
| instance |= 0x08; |
| break; |
| case 16: |
| instance |= 0x10; |
| break; |
| case 32: |
| instance |= 0x20; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| switch (ck_len_bytes) { |
| case 16: |
| break; |
| case 32: |
| instance |= 0x04; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| switch (ik_len_bytes) { |
| case 16: |
| break; |
| case 32: |
| instance |= 0x02; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| switch (k_len_bytes) { |
| case 16: |
| break; |
| case 32: |
| instance |= 0x01; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| tuak_core(buf, opc, instance, _rand, zero16, zero16, k, k_len_bytes, keccac_iterations); |
| |
| if (res) |
| memcpy_reverse(res, buf, res_len_bytes); |
| |
| if (ck) |
| memcpy_reverse(ck, buf + 32, ck_len_bytes); |
| |
| if (ik) |
| memcpy_reverse(ik, buf + 64, ik_len_bytes); |
| |
| if (ak) |
| memcpy_reverse(ak, buf + 96, 6); |
| |
| return 0; |
| } |
| |
| /** |
| * tuak_f5star - TUAK f5* algorithm |
| * @opc: OPc = 256-bit value derived from OP and K |
| * @k: K = 128/256-bit subscriber key |
| * @_rand: RAND = 128-bit random challenge |
| * @ak: Buffer for AK = 48-bit anonymity key (f5) |
| * Returns: 0 on success, -1 on failure |
| */ |
| int tuak_f5star(const uint8_t *opc, const uint8_t *k, uint8_t k_len_bytes, |
| const uint8_t *_rand, uint8_t *ak, unsigned int keccac_iterations) |
| { |
| uint8_t buf[200]; |
| uint8_t instance = 0xc0; |
| |
| switch (k_len_bytes) { |
| case 16: |
| break; |
| case 32: |
| instance += 1; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| tuak_core(buf, opc, instance, _rand, zero16, zero16, k, k_len_bytes, keccac_iterations); |
| |
| memcpy_reverse(ak, buf + 96, 6); |
| |
| return 0; |
| } |
| |
| /** |
| * tuak_generate - Generate AKA AUTN,IK,CK,RES |
| * @opc: OPc = 256-bit operator variant algorithm configuration field (encr.) |
| * @amf: AMF = 16-bit authentication management field |
| * @k: K = 128/256-bit subscriber key |
| * @sqn: SQN = 48-bit sequence number |
| * @_rand: RAND = 128-bit random challenge |
| * @autn: Buffer for AUTN = 128-bit authentication token |
| * @ik: Buffer for IK = 128/256-bit integrity key (f4), or %NULL |
| * @ck: Buffer for CK = 128/256-bit confidentiality key (f3), or %NULL |
| * @res: Buffer for RES = 32/64/128-bit signed response (f2), or %NULL |
| * @res_len: Max length for res; set to used length or 0 on failure |
| */ |
| void tuak_generate(const uint8_t *opc, const uint8_t *amf, const uint8_t *k, uint8_t k_len_bytes, |
| const uint8_t *sqn, const uint8_t *_rand, uint8_t *autn, uint8_t *ik, |
| uint8_t *ck, uint8_t *res, size_t *res_len) |
| { |
| int i; |
| uint8_t mac_a[8], ak[6]; |
| |
| if (*res_len < 4) { |
| *res_len = 0; |
| return; |
| } |
| if (tuak_f1(opc, k, k_len_bytes, _rand, sqn, amf, mac_a, sizeof(mac_a), g_keccak_iterations) || |
| tuak_f2345(opc, k, k_len_bytes, _rand, res, *res_len, ck, 16, ik, 16, ak, g_keccak_iterations)) { |
| *res_len = 0; |
| return; |
| } |
| |
| /* AUTN = (SQN ^ AK) || AMF || MAC */ |
| for (i = 0; i < 6; i++) |
| autn[i] = sqn[i] ^ ak[i]; |
| memcpy(autn + 6, amf, 2); |
| memcpy(autn + 8, mac_a, 8); |
| } |
| |
| |
| /** |
| * tuak_auts - Milenage AUTS validation |
| * @opc: OPc = 256-bit operator variant algorithm configuration field (encr.) |
| * @k: K = 128/256-bit subscriber key |
| * @_rand: RAND = 128-bit random challenge |
| * @auts: AUTS = 112-bit authentication token from client |
| * @sqn: Buffer for SQN = 48-bit sequence number |
| * Returns: 0 = success (sqn filled), -1 on failure |
| */ |
| int tuak_auts(const uint8_t *opc, const uint8_t *k, uint8_t k_len_bytes, |
| const uint8_t *_rand, const uint8_t *auts, uint8_t *sqn) |
| { |
| uint8_t amf[2] = { 0x00, 0x00 }; /* TS 33.102 v7.0.0, 6.3.3 */ |
| uint8_t ak[6], mac_s[8]; |
| int i; |
| |
| if (tuak_f5star(opc, k, k_len_bytes, _rand, ak, g_keccak_iterations)) |
| return -1; |
| for (i = 0; i < 6; i++) |
| sqn[i] = auts[i] ^ ak[i]; |
| if (tuak_f1star(opc, k, k_len_bytes, _rand, sqn, amf, mac_s, 8, g_keccak_iterations) || |
| memcmp(mac_s, auts + 6, 8) != 0) |
| return -1; |
| return 0; |
| } |
| |
| int tuak_opc_gen(uint8_t *opc, const uint8_t *k, uint8_t k_len_bytes, const uint8_t *op) |
| { |
| uint8_t buf[200]; |
| uint8_t instance; |
| |
| switch (k_len_bytes) { |
| case 16: |
| instance = 0x00; |
| break; |
| case 32: |
| instance = 0x01; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| tuak_core(buf, op, instance, zero16, zero16, zero16, k, k_len_bytes, g_keccak_iterations); |
| |
| memcpy_reverse(opc, buf, 32); |
| |
| return 0; |
| } |