forked from acouzens/open5gs
462 lines
13 KiB
C
462 lines
13 KiB
C
/*
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* 3GPP AKA - Milenage algorithm (3GPP TS 35.205, .206, .207, .208)
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* Copyright (c) 2006-2007 <j@w1.fi>
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*
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* This software may be distributed under the terms of the BSD license.
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* See README for more details.
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*
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* This file implements an example authentication algorithm defined for 3GPP
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* AKA. This can be used to implement a simple HLR/AuC into hlr_auc_gw to allow
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* EAP-AKA to be tested properly with real USIM cards.
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*
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* This implementations assumes that the r1..r5 and c1..c5 constants defined in
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* TS 35.206 are used, i.e., r1=64, r2=0, r3=32, r4=64, r5=96, c1=00..00,
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* c2=00..01, c3=00..02, c4=00..04, c5=00..08. The block cipher is assumed to
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* be AES (Rijndael).
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*/
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#include "ogs-crypt.h"
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#include "milenage.h"
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#define os_memcpy memcpy
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#define os_memcmp memcmp
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#define os_memcmp_const memcmp
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static void ShiftBits(uint8_t r, uint8_t rijndaelInput[16],
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uint8_t temp[16], const uint8_t opc[16]);
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static uint8_t *bits_shift(uint32_t bit_valid, uint8_t *dst,
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uint8_t *src, uint32_t numBits);
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static int aes_128_encrypt_block(const uint8_t *key,
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const uint8_t *in, uint8_t *out)
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{
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const int key_bits = 128;
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unsigned int rk[OGS_AES_RKLENGTH(128)];
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int nrounds;
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nrounds = ogs_aes_setup_enc(rk, key, key_bits);
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ogs_aes_encrypt(rk, nrounds, in, out);
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return 0;
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}
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/**
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* milenage_f1 - Milenage f1 and f1* algorithms
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* @opc: OPc = 128-bit value derived from OP and K
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* @k: K = 128-bit subscriber key
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* @_rand: RAND = 128-bit random challenge
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* @sqn: SQN = 48-bit sequence number
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* @amf: AMF = 16-bit authentication management field
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* @mac_a: Buffer for MAC-A = 64-bit network authentication code, or %NULL
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* @mac_s: Buffer for MAC-S = 64-bit resync authentication code, or %NULL
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* Returns: 0 on success, -1 on failure
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*/
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int milenage_f1(const uint8_t *opc, const uint8_t *k,
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const uint8_t *_rand, const uint8_t *sqn,
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const uint8_t *amf, uint8_t *mac_a, uint8_t *mac_s)
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{
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uint8_t tmp1[16], tmp2[16], tmp3[16];
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int i;
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#if 1 /* R1-R5 issues1153 */
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uint8_t r1 = 64;
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#endif
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for (i = 0; i < 16; i++)
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tmp1[i] = _rand[i] ^ opc[i];
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if (aes_128_encrypt_block(k, tmp1, tmp1))
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return -1;
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/* tmp2 = IN1 = SQN || AMF || SQN || AMF */
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os_memcpy(tmp2, sqn, 6);
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os_memcpy(tmp2 + 6, amf, 2);
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os_memcpy(tmp2 + 8, tmp2, 8);
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/* OUT1 = E_K(TEMP XOR rot(IN1 XOR OP_C, r1) XOR c1) XOR OP_C */
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/* rotate (tmp2 XOR OP_C) by r1 (= 0x40 = 8 bytes) */
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#if 0 /* R1-R5 issues1153 */
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for (i = 0; i < 16; i++)
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tmp3[(i + 8) % 16] = tmp2[i] ^ opc[i];
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#else
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ShiftBits(r1, tmp3, tmp2, opc);
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#endif
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/* XOR with TEMP = E_K(RAND XOR OP_C) */
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for (i = 0; i < 16; i++)
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tmp3[i] ^= tmp1[i];
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/* XOR with c1 (= ..00, i.e., NOP) */
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/* f1 || f1* = E_K(tmp3) XOR OP_c */
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if (aes_128_encrypt_block(k, tmp3, tmp1))
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return -1;
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for (i = 0; i < 16; i++)
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tmp1[i] ^= opc[i];
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if (mac_a)
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os_memcpy(mac_a, tmp1, 8); /* f1 */
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if (mac_s)
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os_memcpy(mac_s, tmp1 + 8, 8); /* f1* */
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return 0;
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}
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/**
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* milenage_f2345 - Milenage f2, f3, f4, f5, f5* algorithms
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* @opc: OPc = 128-bit value derived from OP and K
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* @k: K = 128-bit subscriber key
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* @_rand: RAND = 128-bit random challenge
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* @res: Buffer for RES = 64-bit signed response (f2), or %NULL
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* @ck: Buffer for CK = 128-bit confidentiality key (f3), or %NULL
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* @ik: Buffer for IK = 128-bit integrity key (f4), or %NULL
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* @ak: Buffer for AK = 48-bit anonymity key (f5), or %NULL
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* @akstar: Buffer for AK = 48-bit anonymity key (f5*), or %NULL
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* Returns: 0 on success, -1 on failure
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*/
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int milenage_f2345(const uint8_t *opc, const uint8_t *k,
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const uint8_t *_rand, uint8_t *res, uint8_t *ck,
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uint8_t *ik, uint8_t *ak, uint8_t *akstar)
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{
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uint8_t tmp1[16], tmp2[16], tmp3[16];
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int i;
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#if 1 /* R1-R5 issues1153 */
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uint8_t r2 = 0;
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uint8_t r3 = 32;
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uint8_t r4 = 64;
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uint8_t r5 = 96;
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#endif
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/* tmp2 = TEMP = E_K(RAND XOR OP_C) */
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for (i = 0; i < 16; i++)
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tmp1[i] = _rand[i] ^ opc[i];
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if (aes_128_encrypt_block(k, tmp1, tmp2))
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return -1;
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/* OUT2 = E_K(rot(TEMP XOR OP_C, r2) XOR c2) XOR OP_C */
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/* OUT3 = E_K(rot(TEMP XOR OP_C, r3) XOR c3) XOR OP_C */
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/* OUT4 = E_K(rot(TEMP XOR OP_C, r4) XOR c4) XOR OP_C */
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/* OUT5 = E_K(rot(TEMP XOR OP_C, r5) XOR c5) XOR OP_C */
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/* f2 and f5 */
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/* rotate by r2 (= 0, i.e., NOP) */
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#if 0 /* R1-R5 issues1153 */
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for (i = 0; i < 16; i++)
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tmp1[i] = tmp2[i] ^ opc[i];
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#else
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ShiftBits(r2, tmp1, tmp2, opc);
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#endif
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tmp1[15] ^= 1; /* XOR c2 (= ..01) */
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/* f5 || f2 = E_K(tmp1) XOR OP_c */
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if (aes_128_encrypt_block(k, tmp1, tmp3))
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return -1;
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for (i = 0; i < 16; i++)
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tmp3[i] ^= opc[i];
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if (res)
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os_memcpy(res, tmp3 + 8, 8); /* f2 */
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if (ak)
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os_memcpy(ak, tmp3, 6); /* f5 */
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/* f3 */
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if (ck) {
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/* rotate by r3 = 0x20 = 4 bytes */
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#if 0 /* R1-R5 issues1153 */
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for (i = 0; i < 16; i++)
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tmp1[(i + 12) % 16] = tmp2[i] ^ opc[i];
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#else
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ShiftBits(r3, tmp1, tmp2, opc);
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#endif
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tmp1[15] ^= 2; /* XOR c3 (= ..02) */
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if (aes_128_encrypt_block(k, tmp1, ck))
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return -1;
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for (i = 0; i < 16; i++)
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ck[i] ^= opc[i];
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}
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/* f4 */
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if (ik) {
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/* rotate by r4 = 0x40 = 8 bytes */
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#if 0 /* R1-R5 issues1153 */
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for (i = 0; i < 16; i++)
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tmp1[(i + 8) % 16] = tmp2[i] ^ opc[i];
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#else
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ShiftBits(r4, tmp1, tmp2, opc);
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#endif
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tmp1[15] ^= 4; /* XOR c4 (= ..04) */
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if (aes_128_encrypt_block(k, tmp1, ik))
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return -1;
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for (i = 0; i < 16; i++)
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ik[i] ^= opc[i];
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}
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/* f5* */
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if (akstar) {
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/* rotate by r5 = 0x60 = 12 bytes */
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#if 0 /* R1-R5 issues1153 */
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for (i = 0; i < 16; i++)
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tmp1[(i + 4) % 16] = tmp2[i] ^ opc[i];
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#else
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ShiftBits(r5, tmp1, tmp2, opc);
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#endif
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tmp1[15] ^= 8; /* XOR c5 (= ..08) */
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if (aes_128_encrypt_block(k, tmp1, tmp1))
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return -1;
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for (i = 0; i < 6; i++)
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akstar[i] = tmp1[i] ^ opc[i];
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}
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return 0;
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}
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/**
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* milenage_generate - Generate AKA AUTN,IK,CK,RES
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* @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
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* @amf: AMF = 16-bit authentication management field
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* @k: K = 128-bit subscriber key
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* @sqn: SQN = 48-bit sequence number
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* @_rand: RAND = 128-bit random challenge
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* @autn: Buffer for AUTN = 128-bit authentication token
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* @ik: Buffer for IK = 128-bit integrity key (f4), or %NULL
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* @ck: Buffer for CK = 128-bit confidentiality key (f3), or %NULL
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* @res: Buffer for RES = 64-bit signed response (f2), or %NULL
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* @res_len: Max length for res; set to used length or 0 on failure
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*/
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void milenage_generate(const uint8_t *opc, const uint8_t *amf,
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const uint8_t *k, const uint8_t *sqn, const uint8_t *_rand,
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uint8_t *autn, uint8_t *ik, uint8_t *ck, uint8_t *ak,
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uint8_t *res, size_t *res_len)
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{
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int i;
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uint8_t mac_a[8];
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if (*res_len < 8) {
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*res_len = 0;
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return;
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}
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if (milenage_f1(opc, k, _rand, sqn, amf, mac_a, NULL) ||
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milenage_f2345(opc, k, _rand, res, ck, ik, ak, NULL)) {
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*res_len = 0;
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return;
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}
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*res_len = 8;
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/* AUTN = (SQN ^ AK) || AMF || MAC */
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for (i = 0; i < 6; i++)
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autn[i] = sqn[i] ^ ak[i];
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os_memcpy(autn + 6, amf, 2);
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os_memcpy(autn + 8, mac_a, 8);
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}
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/**
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* milenage_auts - Milenage AUTS validation
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* @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
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* @k: K = 128-bit subscriber key
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* @_rand: RAND = 128-bit random challenge
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* @auts: AUTS = 112-bit authentication token from client
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* @sqn: Buffer for SQN = 48-bit sequence number
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* Returns: 0 = success (sqn filled), -1 on failure
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*/
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int milenage_auts(const uint8_t *opc, const uint8_t *k,
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const uint8_t *_rand, const uint8_t *auts, uint8_t *sqn)
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{
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uint8_t amf[2] = { 0x00, 0x00 }; /* TS 33.102 v7.0.0, 6.3.3 */
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uint8_t ak[6], mac_s[8];
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int i;
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if (milenage_f2345(opc, k, _rand, NULL, NULL, NULL, NULL, ak))
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return -1;
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for (i = 0; i < 6; i++)
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sqn[i] = auts[i] ^ ak[i];
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if (milenage_f1(opc, k, _rand, sqn, amf, NULL, mac_s) ||
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os_memcmp_const(mac_s, auts + 6, 8) != 0)
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return -1;
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return 0;
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}
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/**
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* gsm_milenage - Generate GSM-Milenage (3GPP TS 55.205) authentication triplet
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* @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
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* @k: K = 128-bit subscriber key
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* @_rand: RAND = 128-bit random challenge
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* @sres: Buffer for SRES = 32-bit SRES
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* @kc: Buffer for Kc = 64-bit Kc
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* Returns: 0 on success, -1 on failure
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*/
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int gsm_milenage(const uint8_t *opc, const uint8_t *k,
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const uint8_t *_rand, uint8_t *sres, uint8_t *kc)
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{
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uint8_t res[8], ck[16], ik[16];
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int i;
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if (milenage_f2345(opc, k, _rand, res, ck, ik, NULL, NULL))
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return -1;
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for (i = 0; i < 8; i++)
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kc[i] = ck[i] ^ ck[i + 8] ^ ik[i] ^ ik[i + 8];
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#ifdef GSM_MILENAGE_ALT_SRES
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os_memcpy(sres, res, 4);
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#else /* GSM_MILENAGE_ALT_SRES */
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for (i = 0; i < 4; i++)
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sres[i] = res[i] ^ res[i + 4];
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#endif /* GSM_MILENAGE_ALT_SRES */
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return 0;
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}
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/**
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* milenage_generate - Generate AKA AUTN,IK,CK,RES
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* @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
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* @k: K = 128-bit subscriber key
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* @sqn: SQN = 48-bit sequence number
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* @_rand: RAND = 128-bit random challenge
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* @autn: AUTN = 128-bit authentication token
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* @ik: Buffer for IK = 128-bit integrity key (f4), or %NULL
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* @ck: Buffer for CK = 128-bit confidentiality key (f3), or %NULL
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* @res: Buffer for RES = 64-bit signed response (f2), or %NULL
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* @res_len: Variable that will be set to RES length
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* @auts: 112-bit buffer for AUTS
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* Returns: 0 on success, -1 on failure, or -2 on synchronization failure
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*/
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int milenage_check(const uint8_t *opc, const uint8_t *k,
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const uint8_t *sqn, const uint8_t *_rand, const uint8_t *autn,
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uint8_t *ik, uint8_t *ck, uint8_t *res, size_t *res_len,
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uint8_t *auts)
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{
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int i;
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uint8_t mac_a[8], ak[6], rx_sqn[6];
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const uint8_t *amf;
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ogs_log_print(OGS_LOG_INFO, "Milenage: AUTN\n");
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ogs_log_hexdump(OGS_LOG_INFO, autn, 16);
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ogs_log_print(OGS_LOG_INFO, "Milenage: RAND\n");
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ogs_log_hexdump(OGS_LOG_INFO, _rand, 16);
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if (milenage_f2345(opc, k, _rand, res, ck, ik, ak, NULL))
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return -1;
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*res_len = 8;
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ogs_log_print(OGS_LOG_INFO, "Milenage: RES\n");
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ogs_log_hexdump(OGS_LOG_INFO, res, *res_len);
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ogs_log_print(OGS_LOG_INFO, "Milenage: CK\n");
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ogs_log_hexdump(OGS_LOG_INFO, ck, 16);
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ogs_log_print(OGS_LOG_INFO, "Milenage: IK\n");
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ogs_log_hexdump(OGS_LOG_INFO, ik, 16);
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ogs_log_print(OGS_LOG_INFO, "Milenage: AK\n");
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ogs_log_hexdump(OGS_LOG_INFO, ak, 6);
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/* AUTN = (SQN ^ AK) || AMF || MAC */
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for (i = 0; i < 6; i++)
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rx_sqn[i] = autn[i] ^ ak[i];
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ogs_log_print(OGS_LOG_INFO, "Milenage: SQN\n");
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ogs_log_hexdump(OGS_LOG_INFO, rx_sqn, 6);
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if (os_memcmp(rx_sqn, sqn, 6) <= 0) {
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uint8_t auts_amf[2] = { 0x00, 0x00 }; /* TS 33.102 v7.0.0, 6.3.3 */
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if (milenage_f2345(opc, k, _rand, NULL, NULL, NULL, NULL, ak))
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return -1;
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ogs_log_print(OGS_LOG_INFO, "Milenage: AK*\n");
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ogs_log_hexdump(OGS_LOG_INFO, ak, 6);
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for (i = 0; i < 6; i++)
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auts[i] = sqn[i] ^ ak[i];
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if (milenage_f1(opc, k, _rand, sqn, auts_amf, NULL, auts + 6))
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return -1;
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ogs_log_print(OGS_LOG_INFO, "Milenage: AUTS*\n");
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ogs_log_hexdump(OGS_LOG_INFO, auts, 14);
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return -2;
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}
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amf = autn + 6;
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ogs_log_print(OGS_LOG_INFO, "Milenage: AMF\n");
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ogs_log_hexdump(OGS_LOG_INFO, amf, 2);
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if (milenage_f1(opc, k, _rand, rx_sqn, amf, mac_a, NULL))
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return -1;
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ogs_log_print(OGS_LOG_INFO, "Milenage: MAC_A\n");
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ogs_log_hexdump(OGS_LOG_INFO, mac_a, 8);
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if (os_memcmp_const(mac_a, autn + 8, 8) != 0) {
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ogs_log_print(OGS_LOG_INFO, "Milenage: MAC mismatch\n");
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ogs_log_print(OGS_LOG_INFO, "Milenage: Received MAC_A\n");
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ogs_log_hexdump(OGS_LOG_INFO, autn + 8, 8);
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return -1;
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}
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return 0;
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}
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void milenage_opc(const uint8_t *k, const uint8_t *op, uint8_t *opc)
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{
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int i;
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aes_128_encrypt_block(k, op, opc);
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for (i = 0; i < 16; i++)
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{
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opc[i] ^= op[i];
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}
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}
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static void ShiftBits(uint8_t r, uint8_t rijndaelInput[16],
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uint8_t temp[16], const uint8_t opc[16])
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{
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uint32_t deltlen = 16 - (r / 8);
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uint32_t leftout = r % 8;
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uint32_t i;
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if (leftout == 0) {
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for (i = 0; i < 16; i++) {
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rijndaelInput[(i+deltlen) % 16] = temp[i] ^ opc[i];
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}
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} else {
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uint8_t temp1[16];
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uint32_t move_bits;
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uint8_t temp2;
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for (i = 0; i < 16; i++) {
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temp1[(i + deltlen) % 16] = temp[i] ^ opc[i];
|
|
}
|
|
rijndaelInput[15] = 0;
|
|
move_bits = 8 - leftout;
|
|
bits_shift(move_bits, &rijndaelInput[0], temp1, (128 - leftout));
|
|
temp2 = temp1[0] >> (8-leftout);
|
|
rijndaelInput[15] |= temp2;
|
|
}
|
|
}
|
|
|
|
static uint8_t *bits_shift(uint32_t bit_valid, uint8_t *dst,
|
|
uint8_t *src, uint32_t numBits)
|
|
{
|
|
uint32_t bit_used = bit_valid;
|
|
uint32_t bit_empty = 8 - bit_used;
|
|
uint32_t numBytes = numBits >> 3;
|
|
uint32_t leftBits = numBits & 0x7;
|
|
uint32_t i = 0;
|
|
uint8_t *newDst = 0;
|
|
|
|
for (i = 0; i < numBytes; i++) {
|
|
dst[i] = (src[i] << bit_empty) | (src[i+1] >> bit_used);
|
|
}
|
|
|
|
if (leftBits) {
|
|
if (leftBits == bit_used) {
|
|
dst[numBytes] = src[numBytes] << bit_empty;
|
|
bit_valid = 8;
|
|
newDst = &src[numBytes+1];
|
|
} else if (leftBits < bit_used) {
|
|
dst[numBytes] = src[numBytes] << bit_empty;
|
|
bit_valid = bit_used - leftBits;
|
|
newDst = &src[numBytes];
|
|
} else {
|
|
dst[numBytes] = src[numBytes] << bit_empty |
|
|
(src[numBytes+1] >> bit_used);
|
|
bit_valid = 8 - (leftBits - bit_used);
|
|
newDst = &src[numBytes+1];
|
|
}
|
|
} else {
|
|
bit_valid = bit_used;
|
|
newDst = &src[numBytes];
|
|
}
|
|
|
|
return newDst;
|
|
}
|