src/shared/libosmocore/src/gsm/auth_milenage.c

   1 /* GSM/GPRS/3G authentication core infrastructure */
   2
   3 /* (C) 2011 by Harald Welte <laforge@gnumonks.org>
   4  *
   5  * All Rights Reserved
   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
  19 #include <osmocom/crypt/auth.h>
  20 #include "milenage/common.h"
  21 #include "milenage/milenage.h"
  22
  23 static void sqn_u64_to_48bit(uint8_t *sqn, const uint64_t sqn64)
  24 {
  25         sqn[5] = (sqn64 >>  0) & 0xff;
  26         sqn[4] = (sqn64 >>  8) & 0xff;
  27         sqn[3] = (sqn64 >> 16) & 0xff;
  28         sqn[2] = (sqn64 >> 24) & 0xff;
  29         sqn[1] = (sqn64 >> 32) & 0xff;
  30         sqn[0] = (sqn64 >> 40) & 0xff;
  31 }
  32
  33 static uint64_t sqn_48bit_to_u64(const uint8_t *sqn)
  34 {
  35         uint64_t sqn64;
  36
  37         sqn64 = sqn[0];
  38         sqn64 <<= 8;
  39         sqn64 |= sqn[1];
  40         sqn64 <<= 8;
  41         sqn64 |= sqn[2];
  42         sqn64 <<= 8;
  43         sqn64 |= sqn[3];
  44         sqn64 <<= 8;
  45         sqn64 |= sqn[4];
  46         sqn64 <<= 8;
  47         sqn64 |= sqn[5];
  48
  49         return sqn64;
  50 }
  51
  52
  53 static int milenage_gen_vec(struct osmo_auth_vector *vec,
  54                             struct osmo_sub_auth_data *aud,
  55                             const uint8_t *_rand)
  56 {
  57         size_t res_len = sizeof(vec->res);
  58         uint8_t sqn[6];
  59         int rc;
  60
  61         sqn_u64_to_48bit(sqn, aud->u.umts.sqn);
  62         milenage_generate(aud->u.umts.opc, aud->u.umts.amf, aud->u.umts.k,
  63                           sqn, _rand,
  64                           vec->autn, vec->ik, vec->ck, vec->res, &res_len);
  65         vec->res_len = res_len;
  66         rc = gsm_milenage(aud->u.umts.opc, aud->u.umts.k, _rand, vec->sres, vec->kc);
  67         if (rc < 0)
  68                 return rc;
  69
  70         vec->auth_types = OSMO_AUTH_TYPE_UMTS | OSMO_AUTH_TYPE_GSM;
  71         aud->u.umts.sqn++;
  72
  73         return 0;
  74 }
  75
  76 static int milenage_gen_vec_auts(struct osmo_auth_vector *vec,
  77                                  struct osmo_sub_auth_data *aud,
  78                                  const uint8_t *auts, const uint8_t *rand_auts,
  79                                  const uint8_t *_rand)
  80 {
  81         uint8_t sqn_out[6];
  82         uint8_t gen_opc[16];
  83         uint8_t *opc;
  84         int rc;
  85
  86         /* Check if we only know OP and compute OPC if required */
  87         if (aud->type == OSMO_AUTH_TYPE_UMTS && aud->u.umts.opc_is_op) {
  88                 rc = milenage_opc_gen(gen_opc, aud->u.umts.k,
  89                                       aud->u.umts.opc);
  90                 if (rc < 0)
  91                         return rc;
  92                 opc = gen_opc;
  93         } else
  94                 opc = aud->u.umts.opc;
  95
  96         rc = milenage_auts(opc, aud->u.umts.k, rand_auts, auts, sqn_out);
  97         if (rc < 0)
  98                 return rc;
  99
 100         aud->u.umts.sqn = sqn_48bit_to_u64(sqn_out) + 1;
 101
 102         return milenage_gen_vec(vec, aud, _rand);
 103 }
 104
 105 static struct osmo_auth_impl milenage_alg = {
 106         .algo = OSMO_AUTH_ALG_MILENAGE,
 107         .name = "MILENAGE (libosmogsm built-in)",
 108         .priority = 1000,
 109         .gen_vec = &milenage_gen_vec,
 110         .gen_vec_auts = &milenage_gen_vec_auts,
 111 };
 112
 113 static __attribute__((constructor)) void on_dso_load_milenage(void)
 114 {
 115         osmo_auth_register(&milenage_alg);
 116 }