osa_stream_eea.c 6.93 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
/*******************************************************************************
    OpenAirInterface
    Copyright(c) 1999 - 2014 Eurecom

    OpenAirInterface 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 3 of the License, or
    (at your option) any later version.


    OpenAirInterface 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.

    You should have received a copy of the GNU General Public License
    along with OpenAirInterface.The full GNU General Public License is
    included in this distribution in the file called "COPYING". If not,
    see <http://www.gnu.org/licenses/>.

  Contact Information
  OpenAirInterface Admin: openair_admin@eurecom.fr
  OpenAirInterface Tech : openair_tech@eurecom.fr
24
  OpenAirInterface Dev  : openair4g-devel@lists.eurecom.fr
25

ghaddab's avatar
ghaddab committed
26
  Address      : Eurecom, Campus SophiaTech, 450 Route des Chappes, CS 50193 - 06904 Biot Sophia Antipolis cedex, FRANCE
27 28 29

*******************************************************************************/

30 31 32 33 34 35 36 37 38 39 40 41 42
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>

#include <nettle/nettle-meta.h>
#include <nettle/aes.h>
#include <nettle/ctr.h>

#include "UTIL/LOG/log.h"

#include "assertions.h"
#include "osa_defs.h"
Lionel Gauthier's avatar
 
Lionel Gauthier committed
43
#include "osa_snow3g.h"
44 45
#include "osa_internal.h"

46 47
int stream_encrypt_eea0(stream_cipher_t *stream_cipher, uint8_t **out)
{
48
  uint8_t *data = NULL;
49

50
  uint32_t byte_length;
51

52 53
  DevAssert(stream_cipher != NULL);
  DevAssert(out != NULL);
54

55 56 57 58
  LOG_D(OSA, "Entering stream_encrypt_eea0, bits length %u, bearer %u, "
        "count %u, direction %s\n", stream_cipher->blength,
        stream_cipher->bearer, stream_cipher->count, stream_cipher->direction == SECU_DIRECTION_DOWNLINK ?
        "Downlink" : "Uplink");
59

60
  byte_length = (stream_cipher->blength + 7) >> 3;
61

62 63 64 65 66 67 68
  if (*out == NULL) {
    /* User did not provide output buffer */
    data = malloc(byte_length);
    *out = data;
  } else {
    data = *out;
  }
69

70
  memcpy (data, stream_cipher->message, byte_length);
71

72
  return 0;
73 74
}

Lionel Gauthier's avatar
 
Lionel Gauthier committed
75 76
int stream_encrypt_eea1(stream_cipher_t *stream_cipher, uint8_t **out)
{
77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142
  osa_snow_3g_context_t snow_3g_context;
  int       n ;
  int       i           = 0;
  uint32_t  zero_bit    = 0;
  uint32_t *KS;
  uint32_t  K[4],IV[4];

  DevAssert(stream_cipher != NULL);
  DevAssert(stream_cipher->key != NULL);
  DevAssert(stream_cipher->key_length == 16);
  DevAssert(out != NULL);

  n = ( stream_cipher->blength + 31 ) / 32;
  zero_bit = stream_cipher->blength & 0x7;

  memset(&snow_3g_context, 0, sizeof(snow_3g_context));
  /*Initialisation*/
  /* Load the confidentiality key for SNOW 3G initialization as in section
  3.4. */
  memcpy(K+3,stream_cipher->key+0,4); /*K[3] = key[0]; we assume
  K[3]=key[0]||key[1]||...||key[31] , with key[0] the
  * most important bit of key*/
  memcpy(K+2,stream_cipher->key+4,4); /*K[2] = key[1];*/
  memcpy(K+1,stream_cipher->key+8,4); /*K[1] = key[2];*/
  memcpy(K+0,stream_cipher->key+12,4); /*K[0] = key[3]; we assume
  K[0]=key[96]||key[97]||...||key[127] , with key[127] the
  * least important bit of key*/
  K[3] = hton_int32(K[3]);
  K[2] = hton_int32(K[2]);
  K[1] = hton_int32(K[1]);
  K[0] = hton_int32(K[0]);
  /* Prepare the initialization vector (IV) for SNOW 3G initialization as in
  section 3.4. */
  IV[3] = stream_cipher->count;
  IV[2] = ((((uint32_t)stream_cipher->bearer) << 3) | ((((uint32_t)stream_cipher->direction) & 0x1) << 2)) << 24;
  IV[1] = IV[3];
  IV[0] = IV[2];

  /* Run SNOW 3G algorithm to generate sequence of key stream bits KS*/
  osa_snow3g_initialize(K, IV, &snow_3g_context);
  KS = (uint32_t *)malloc(4*n);
  osa_snow3g_generate_key_stream(n,(uint32_t*)KS, &snow_3g_context);

  if (zero_bit > 0) {

    KS[n - 1] = KS[n - 1] & (uint32_t)(0xFFFFFFFF << (8 - zero_bit));
  }

  for (i=0; i<n; i++) {
    KS[i] = hton_int32(KS[i]);
  }

  /* Exclusive-OR the input data with keystream to generate the output bit
  stream */
  for (i=0; i<n*4; i++) {
    stream_cipher->message[i] ^= *(((uint8_t*)KS)+i);
  }

  if (zero_bit > 0) {
    int ceil_index = (stream_cipher->blength+7) >> 3;
    stream_cipher->message[ceil_index - 1] = stream_cipher->message[ceil_index - 1] & (uint8_t)(0xFF << (8 - zero_bit));
  }

  free(KS);
  *out = stream_cipher->message;
  return 0;
Lionel Gauthier's avatar
 
Lionel Gauthier committed
143 144
}

145 146
int stream_encrypt_eea2(stream_cipher_t *stream_cipher, uint8_t **out)
{
147 148
  uint8_t m[16];
  uint32_t local_count;
149

150 151
  void *ctx;
  uint8_t *data = NULL;
152

153 154
  uint32_t zero_bit = 0;
  uint32_t byte_length;
155

156 157
  DevAssert(stream_cipher != NULL);
  DevAssert(out != NULL);
158

159 160 161 162
  LOG_D(OSA, "Entering stream_encrypt_eea2, bits length %u, bearer %u, "
        "count %u, direction %s\n", stream_cipher->blength,
        stream_cipher->bearer, stream_cipher->count, stream_cipher->direction == SECU_DIRECTION_DOWNLINK ?
        "Downlink" : "Uplink");
163

164
  zero_bit = stream_cipher->blength & 0x7;
165

166
  byte_length = stream_cipher->blength >> 3;
167

168 169
  if (zero_bit > 0)
    byte_length += 1;
170

171
  ctx = malloc(nettle_aes128.context_size);
172

173 174 175 176 177 178 179
  if (*out == NULL) {
    /* User provided output buffer */
    data = malloc(byte_length);
    *out = data;
  } else {
    data = *out;
  }
180

181 182 183 184 185 186 187
  local_count = hton_int32(stream_cipher->count);

  memset(m, 0, sizeof(m));
  memcpy(&m[0], &local_count, 4);
  m[4] = ((stream_cipher->bearer & 0x1F) << 3) |
         ((stream_cipher->direction & 0x01) << 2);
  /* Other bits are 0 */
188 189

#if defined(SECU_DEBUG)
190 191 192 193 194 195 196 197 198 199
  {
    int i;
    char payload[6 * byte_length + 1];
    int  index = 0;

    for (i = 0; i < byte_length; i++)
      index += sprintf(&payload[index], "0x%02x ", stream_cipher->message[i]);

    LOG_D(OSA, "Original message: %s\n", payload);
  }
200 201
#endif

202 203
  nettle_aes128.set_encrypt_key(ctx, stream_cipher->key_length,
                                stream_cipher->key);
204

205 206 207
  nettle_ctr_crypt(ctx, nettle_aes128.encrypt,
                   nettle_aes128.block_size, m,
                   byte_length, data, stream_cipher->message);
208

209 210
  if (zero_bit > 0)
    data[byte_length - 1] = data[byte_length - 1] & (uint8_t)(0xFF << (8 - zero_bit));
211

212
  free(ctx);
213 214

#if defined(SECU_DEBUG)
215 216 217 218 219 220 221 222 223 224
  {
    int i;
    char payload[6 * byte_length + 1];
    int  index = 0;

    for (i = 0; i < byte_length; i++)
      index += sprintf(&payload[index], "0x%02x ", data[i]);

    LOG_D(OSA, "Encrypted message: %s\n", payload);
  }
225 226
#endif

227
  return 0;
228 229 230 231
}

int stream_encrypt(uint8_t algorithm, stream_cipher_t *stream_cipher, uint8_t **out)
{
232 233 234 235 236 237 238 239 240 241
  if (algorithm == EEA0_ALG_ID) {
    return stream_encrypt_eea0(stream_cipher, out);
  } else if (algorithm == EEA1_128_ALG_ID) {
    return stream_encrypt_eea1(stream_cipher, out);
  } else if (algorithm == EEA2_128_ALG_ID) {
    return stream_encrypt_eea2(stream_cipher, out);
  }

  LOG_E(OSA, "Provided encryption algorithm is currently not supported = %u\n", algorithm);
  return -1;
242
}