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Diffstat (limited to 'src/gsm/tuak/tuak.c')
| -rw-r--r-- | src/gsm/tuak/tuak.c | 372 |
1 files changed, 372 insertions, 0 deletions
diff --git a/src/gsm/tuak/tuak.c b/src/gsm/tuak/tuak.c new file mode 100644 index 00000000..c044a377 --- /dev/null +++ b/src/gsm/tuak/tuak.c @@ -0,0 +1,372 @@ +/* (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; +} |