SecurityModeControl.c 23.6 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.0  (the "License"); you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.openairinterface.org/?page_id=698
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *-------------------------------------------------------------------------------
 * For more information about the OpenAirInterface (OAI) Software Alliance:
 *      contact@openairinterface.org
 */
gauthier's avatar
 
gauthier committed
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67

/*****************************************************************************
Source      SecurityModeControl.c

Version     0.1

Date        2013/04/22

Product     NAS stack

Subsystem   Template body file

Author      Frederic Maurel

Description Defines the security mode control EMM procedure executed by the
        Non-Access Stratum.

        The purpose of the NAS security mode control procedure is to
        take an EPS security context into use, and initialise and start
        NAS signalling security between the UE and the MME with the
        corresponding EPS NAS keys and EPS security algorithms.

        Furthermore, the network may also initiate a SECURITY MODE COM-
        MAND in order to change the NAS security algorithms for a cur-
        rent EPS security context already in use.

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

#include <stdlib.h> // malloc, free
#include <string.h> // memcpy
#include <inttypes.h>

#include "emm_proc.h"
#include "nas_log.h"
#include "nas_timer.h"

#include "emmData.h"

#include "emm_sap.h"
#include "emm_cause.h"

#include "UeSecurityCapability.h"

# include "assertions.h"
#include "secu_defs.h"
#include "msc.h"

68
#if  defined(NAS_BUILT_IN_UE)
69
#include "nas_itti_messaging.h"
70
#endif
71

gauthier's avatar
 
gauthier committed
72 73 74 75 76 77 78 79 80 81 82 83 84 85
/****************************************************************************/
/****************  E X T E R N A L    D E F I N I T I O N S  ****************/
/****************************************************************************/

/****************************************************************************/
/*******************  L O C A L    D E F I N I T I O N S  *******************/
/****************************************************************************/

/*
 * --------------------------------------------------------------------------
 *  Internal data handled by the security mode control procedure in the UE
 * --------------------------------------------------------------------------
 */
static int _security_kdf(const OctetString *kasme, OctetString *key,
86
                         uint8_t algo_dist, uint8_t algo_id);
gauthier's avatar
 
gauthier committed
87 88

static int _security_knas_enc(const OctetString *kasme, OctetString *knas_enc,
89
                              uint8_t eia);
gauthier's avatar
 
gauthier committed
90
static int _security_knas_int(const OctetString *kasme, OctetString *knas_int,
91
                              uint8_t eea);
gauthier's avatar
 
gauthier committed
92
static int _security_kenb(const OctetString *kasme, OctetString *kenb,
93
                          uint32_t count);
gauthier's avatar
 
gauthier committed
94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148

/*
 * Internal data used for security mode control procedure
 */
static struct {
  OctetString kenb;           /* eNodeB security key      */
} _security_data;

static void _security_release(emm_security_context_t *ctx);

/*
 * --------------------------------------------------------------------------
 *  Internal data handled by the security mode control procedure in the MME
 * --------------------------------------------------------------------------
 */

/****************************************************************************/
/******************  E X P O R T E D    F U N C T I O N S  ******************/
/****************************************************************************/

/*
 * --------------------------------------------------------------------------
 *      Security mode control procedure executed by the UE
 * --------------------------------------------------------------------------
 */
/****************************************************************************
 **                                                                        **
 ** Name:    emm_proc_security_mode_command()                              **
 **                                                                        **
 ** Description: Performs the MME requested security mode control proce-   **
 **      dure.                                                             **
 **                                                                        **
 **              3GPP TS 24.301, section 5.4.3.3                           **
 **      Upon receiving the SECURITY MODE COMMAND message, the UE          **
 **      shall check whether the message can be accepted or not.           **
 **      If accepted the UE shall send a SECURITY MODE COMPLETE            **
 **      message integrity protected with the selected NAS inte-           **
 **      grity algorithm and ciphered with the selected NAS ciphe-         **
 **      ring algorithm.                                                   **
 **                                                                        **
 ** Inputs:  native_ksi:    TRUE if the security context is of type        **
 **             native (for KSIASME)                                       **
 **      ksi:       The NAS ket sey identifier                             **
 **      seea:      Selected EPS cyphering algorithm                       **
 **      seia:      Selected EPS integrity algorithm                       **
 **      reea:      Replayed EPS cyphering algorithm                       **
 **      reia:      Replayed EPS integrity algorithm                       **
 **      Others:    None                                                   **
 **                                                                        **
 ** Outputs:     None                                                      **
 **      Return:    RETURNok, RETURNerror                                  **
 **      Others:    None                                                   **
 **                                                                        **
 ***************************************************************************/
int emm_proc_security_mode_command(int native_ksi, int ksi,
149
                                   int seea, int seia, int reea, int reia, int imeisv_request)
gauthier's avatar
 
gauthier committed
150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165
{
  LOG_FUNC_IN;

  int rc = RETURNerror;
  int emm_cause = EMM_CAUSE_SUCCESS;
  int security_context_is_new = FALSE;

  LOG_TRACE(INFO, "EMM-PROC  - Security mode control requested (ksi=%d)",
            ksi);

  /* Delete any previously stored RAND and RES and stop timer T3416 */
  (void) emm_proc_authentication_delete();

  /*
   * Check the replayed UE security capabilities
   */
166 167
  uint8_t eea = (0x80 >> _emm_data.security->capability.eps_encryption);
  uint8_t eia = (0x80 >> _emm_data.security->capability.eps_integrity);
gauthier's avatar
 
gauthier committed
168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239

  if ( (reea != eea) || (reia != eia) ) {
    LOG_TRACE(WARNING, "EMM-PROC  - Replayed UE security capabilities "
              "rejected");
    emm_cause = EMM_CAUSE_UE_SECURITY_MISMATCH;

    /* XXX - For testing purpose UE always accepts EIA0
     * The UE shall accept "null integrity protection algorithm" EIA0 only
     * if a PDN connection for emergency bearer services is established or
     * the UE is establishing a PDN connection for emergency bearer services
     */
  }
  /*
   * Check the non-current EPS security context
   */
  else if (_emm_data.non_current == NULL) {
    LOG_TRACE(WARNING, "EMM-PROC  - Non-current EPS security context "
              "is not valid");
    emm_cause = EMM_CAUSE_SECURITY_MODE_REJECTED;
  }
  /*
   * Update the non-current EPS security context
   */
  else {
    LOG_TRACE(INFO, "EMM-PROC  - Update the non-current EPS security context seea=%u seia=%u", seea, seia);
    /* Update selected cyphering and integrity algorithms */
    //LG COMENTED _emm_data.non_current->capability.encryption = seea;
    //LG COMENTED _emm_data.non_current->capability.integrity  = seia;

    _emm_data.non_current->selected_algorithms.encryption = seea;
    _emm_data.non_current->selected_algorithms.integrity = seia;

    /* Derive the NAS cyphering key */
    if (_emm_data.non_current->knas_enc.value == NULL) {
      _emm_data.non_current->knas_enc.value =
        (uint8_t *)calloc(1,AUTH_KNAS_ENC_SIZE);
      _emm_data.non_current->knas_enc.length = AUTH_KNAS_ENC_SIZE;
    }

    if (_emm_data.non_current->knas_enc.value != NULL) {
      LOG_TRACE(INFO, "EMM-PROC  - Update the non-current EPS security context knas_enc");
      rc = _security_knas_enc(&_emm_data.non_current->kasme,
                              &_emm_data.non_current->knas_enc, seea);
    }

    /* Derive the NAS integrity key */
    if (_emm_data.non_current->knas_int.value == NULL) {
      _emm_data.non_current->knas_int.value =
        (uint8_t *)calloc(1,AUTH_KNAS_INT_SIZE);
      _emm_data.non_current->knas_int.length = AUTH_KNAS_INT_SIZE;
    }

    if (_emm_data.non_current->knas_int.value != NULL) {
      if (rc != RETURNerror) {
        LOG_TRACE(INFO, "EMM-PROC  - Update the non-current EPS security context knas_int");
        rc = _security_knas_int(&_emm_data.non_current->kasme,
                                &_emm_data.non_current->knas_int, seia);
      }
    }

    /* Derive the eNodeB key */
    if (_security_data.kenb.value == NULL) {
      _security_data.kenb.value = (uint8_t *)calloc(1,AUTH_KENB_SIZE);
      _security_data.kenb.length = AUTH_KENB_SIZE;
    }

    if (_security_data.kenb.value != NULL) {
      if (rc != RETURNerror) {
        LOG_TRACE(INFO, "EMM-PROC  - Update the non-current EPS security context kenb");
        // LG COMMENT rc = _security_kenb(&_emm_data.security->kasme,
        rc = _security_kenb(&_emm_data.non_current->kasme,
                            &_security_data.kenb,
240
                            *(uint32_t *)(&_emm_data.non_current->ul_count));
gauthier's avatar
 
gauthier committed
241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292
      }
    }

    /*
     * NAS security mode command accepted by the UE
     */
    if (rc != RETURNerror) {
      LOG_TRACE(INFO, "EMM-PROC  - NAS security mode command accepted by the UE");

      /* Update the current EPS security context */
      if ( native_ksi && (_emm_data.security->type != EMM_KSI_NATIVE) ) {
        /* The type of security context flag included in the SECURITY
         * MODE COMMAND message is set to "native security context" and
         * the UE has a mapped EPS security context as the current EPS
         * security context */
        if ( (_emm_data.non_current->type == EMM_KSI_NATIVE) &&
             (_emm_data.non_current->eksi == ksi) ) {
          /* The KSI matches the non-current native EPS security
           * context; the UE shall take the non-current native EPS
           * security context into use which then becomes the
           * current native EPS security context and delete the
           * mapped EPS security context */
          LOG_TRACE(INFO,
                    "EMM-PROC  - Update Current security context");
          /* Release non-current security context */
          _security_release(_emm_data.security);
          _emm_data.security = _emm_data.non_current;
          /* Reset the uplink NAS COUNT counter */
          _emm_data.security->ul_count.overflow = 0;
          _emm_data.security->ul_count.seq_num = 0;
          /* Set new security context indicator */
          security_context_is_new = TRUE;
        }
      }

      if ( !native_ksi && (_emm_data.security->type != EMM_KSI_NATIVE) ) {
        /* The type of security context flag included in the SECURITY
         * MODE COMMAND message is set to "mapped security context" and
         * the UE has a mapped EPS security context as the current EPS
         * security context */
        if (ksi != _emm_data.security->eksi) {
          /* The KSI does not match the current EPS security context;
           * the UE shall reset the uplink NAS COUNT counter */
          LOG_TRACE(INFO,
                    "EMM-PROC  - Reset uplink NAS COUNT counter");
          _emm_data.security->ul_count.overflow = 0;
          _emm_data.security->ul_count.seq_num = 0;
        }
      }

      _emm_data.security->selected_algorithms.encryption = seea;
      _emm_data.security->selected_algorithms.integrity  = seia;
293
#if  defined(NAS_BUILT_IN_UE)
294
      nas_itti_kenb_refresh_req(_security_data.kenb.value);
295
#endif
gauthier's avatar
 
gauthier committed
296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331
    }
    /*
     * NAS security mode command not accepted by the UE
     */
    else {
      /* Setup EMM cause code */
      emm_cause = EMM_CAUSE_SECURITY_MODE_REJECTED;

      /* Release security mode control internal data */
      if (_security_data.kenb.value) {
        free(_security_data.kenb.value);
        _security_data.kenb.value = NULL;
        _security_data.kenb.length = 0;
      }
    }
  }

  /* Setup EMM procedure handler to be executed upon receiving
   * lower layer notification */
  rc = emm_proc_lowerlayer_initialize(NULL, NULL, NULL, NULL);

  if (rc != RETURNok) {
    LOG_TRACE(WARNING,
              "EMM-PROC  - Failed to initialize EMM procedure handler");
    LOG_FUNC_RETURN (RETURNerror);
  }

  /*
   * Notify EMM-AS SAP that Security Mode response message has to be sent
   * to the network
   */
  emm_sap_t emm_sap;
  emm_sap.primitive = EMMAS_SECURITY_RES;
  emm_sap.u.emm_as.u.security.guti = _emm_data.guti;
  emm_sap.u.emm_as.u.security.ueid = 0;
  emm_sap.u.emm_as.u.security.msgType = EMM_AS_MSG_TYPE_SMC;
332
  emm_sap.u.emm_as.u.security.imeisv_request = imeisv_request;
gauthier's avatar
 
gauthier committed
333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418
  emm_sap.u.emm_as.u.security.emm_cause = emm_cause;
  /* Setup EPS NAS security data */
  emm_as_set_security_data(&emm_sap.u.emm_as.u.security.sctx,
                           _emm_data.security, security_context_is_new, TRUE);
  rc = emm_sap_send(&emm_sap);

  LOG_FUNC_RETURN (rc);
}


/****************************************************************************/
/*********************  L O C A L    F U N C T I O N S  *********************/
/****************************************************************************/

/*
 * --------------------------------------------------------------------------
 *              UE specific local functions
 * --------------------------------------------------------------------------
 */

/****************************************************************************
 **                                                                        **
 ** Name:    _security_release()                                       **
 **                                                                        **
 ** Description: Releases the given EPS NAS security context               **
 **                                                                        **
 ** Inputs:  ctx:       The EPS NAS security context to release    **
 **      Others:    None                                       **
 **                                                                        **
 ** Outputs:     None                                                      **
 **      Return:    None                                       **
 **      Others:    None                                       **
 **                                                                        **
 ***************************************************************************/
static void _security_release(emm_security_context_t *ctx)
{
  LOG_FUNC_IN;

  if (ctx) {
    /* Release Kasme security key */
    if (ctx->kasme.value) {
      free(ctx->kasme.value);
      ctx->kasme.value  = NULL;
      ctx->kasme.length = 0;
    }

    /* Release NAS cyphering key */
    if (ctx->knas_enc.value) {
      free(ctx->knas_enc.value);
      ctx->knas_enc.value  = NULL;
      ctx->knas_enc.length = 0;
    }

    /* Release NAS integrity key */
    if (ctx->knas_int.value) {
      free(ctx->knas_int.value);
      ctx->knas_int.value  = NULL;
      ctx->knas_int.length = 0;
    }

    /* Release the NAS security context */
    free(ctx);
  }

  LOG_FUNC_OUT;
}

/****************************************************************************
 **                                                                        **
 ** Name:    _security_knas_enc()                                      **
 **                                                                        **
 ** Description: Algorithm Key generation function used for the derivation **
 **      of NAS encryption key Knas-enc from the Kasme.            **
 **                                                                        **
 **              3GPP TS 33.401, Annex A.7                                 **
 **                                                                        **
 ** Inputs:  kasme:     Key Access Security Management Entity      **
 **      eea:       Cyphering algorithm identity               **
 **      Others:    None                                       **
 **                                                                        **
 ** Outputs:     knas_enc:  Derived key for NAS cyphering algorithm    **
 **      Return:    RETURNok, RETURNerror                      **
 **      Others:    None                                       **
 **                                                                        **
 ***************************************************************************/
static int _security_knas_enc(const OctetString *kasme, OctetString *knas_enc,
419
                              uint8_t eea)
gauthier's avatar
 
gauthier committed
420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444
{
  LOG_FUNC_IN;
  LOG_TRACE(INFO, "%s  with algo dist %d algo id %d", __FUNCTION__,0x01, eea);
  LOG_FUNC_RETURN (_security_kdf(kasme, knas_enc, 0x01, eea));
}

/****************************************************************************
 **                                                                        **
 ** Name:    _security_knas_int()                                      **
 **                                                                        **
 ** Description: Algorithm Key generation function used for the derivation **
 **      of NAS integrity key Knas-int from the Kasme.             **
 **                                                                        **
 **              3GPP TS 33.401, Annex A.7                                 **
 **                                                                        **
 ** Inputs:  kasme:     Key Access Security Management Entity      **
 **      eia:       Integrity algorithm identity               **
 **      Others:    None                                       **
 **                                                                        **
 ** Outputs:     knas_int:  Derived key for NAS integrity algorithm    **
 **      Return:    RETURNok, RETURNerror                      **
 **      Others:    None                                       **
 **                                                                        **
 ***************************************************************************/
static int _security_knas_int(const OctetString *kasme, OctetString *knas_int,
445
                              uint8_t eia)
gauthier's avatar
 
gauthier committed
446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470
{
  LOG_FUNC_IN;
  LOG_TRACE(INFO, "%s  with algo dist %d algo id %d", __FUNCTION__,0x02, eia);
  LOG_FUNC_RETURN (_security_kdf(kasme, knas_int, 0x02, eia));
}

/****************************************************************************
 **                                                                        **
 ** Name:    _security_kenb()                                          **
 **                                                                        **
 ** Description: Computes the eNodeB key from Kasme and the given value of **
 **      uplink NAS counter.                                       **
 **                                                                        **
 **              3GPP TS 33.401, Annex A.3                                 **
 **                                                                        **
 ** Inputs:  kasme:     Key Access Security Management Entity      **
 **      count:     Uplink NAS counter value                   **
 **      Others:    None                                       **
 **                                                                        **
 ** Outputs:     kenb:      eNodeB security key                        **
 **      Return:    RETURNok, RETURNerror                      **
 **      Others:    None                                       **
 **                                                                        **
 ***************************************************************************/
static int _security_kenb(const OctetString *kasme, OctetString *kenb,
471
                          uint32_t count)
gauthier's avatar
 
gauthier committed
472 473 474 475
{
  /* Compute the KDF input parameter
   * S = FC(0x11) || UL NAS Count || 0x00 0x04
   */
476 477
  uint8_t  input[32];
  //    uint16_t length    = 4;
gauthier's avatar
 
gauthier committed
478 479 480 481 482 483 484
  //    int      offset    = 0;

  LOG_TRACE(INFO, "%s  with count= %d", __FUNCTION__, count);
  memset(input, 0, 32);
  input[0] = 0x11;
  // P0
  input[1] = count >> 24;
485 486 487
  input[2] = (uint8_t)(count >> 16);
  input[3] = (uint8_t)(count >> 8);
  input[4] = (uint8_t)count;
gauthier's avatar
 
gauthier committed
488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517
  // L0
  input[5] = 0;
  input[6] = 4;

  kdf(kasme->value, 32, input, 7, kenb->value, 32);
  kenb->length = 32;
  return (RETURNok);
}

/****************************************************************************
 **                                                                        **
 ** Name:    _security_kdf()                                           **
 **                                                                        **
 ** Description: Algorithm Key generation function used for the derivation **
 **      of keys for NAS integrity and NAS encryption algorithms   **
 **      from Kasme, algorithm types and algorithm identities.     **
 **                                                                        **
 **              3GPP TS 33.401, Annex A.7                                 **
 **                                                                        **
 ** Inputs:  kasme:     Key Access Security Management Entity      **
 **      algo_dist: Algorithm type distinguisher               **
 **      algo_id:   Algorithm identity                         **
 **      Others:    None                                       **
 **                                                                        **
 ** Outputs:     key:       Derived key for NAS security protection    **
 **      Return:    RETURNok, RETURNerror                      **
 **      Others:    None                                       **
 **                                                                        **
 ***************************************************************************/
static int _security_kdf(const OctetString *kasme, OctetString *key,
518
                         uint8_t algo_dist, uint8_t algo_id)
gauthier's avatar
 
gauthier committed
519 520 521 522 523
{
  /* Compute the KDF input parameter
   * S = FC(0x15) || Algorithm distinguisher || 0x00 0x01
          || Algorithm identity || 0x00 0x01
  */
524 525
  uint8_t input[32];
  uint8_t output[32];
gauthier's avatar
 
gauthier committed
526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549
  LOG_TRACE(DEBUG, "%s:%u output key mem %p lenth %u",
            __FUNCTION__, __LINE__,
            key->value,
            key->length);
  memset(input, 0, 32);
  // FC
  input[0] = 0x15;
  // P0 = Algorithm distinguisher
  input[1] = algo_dist;
  // L0 = 0x00 01
  input[2] = 0x00;
  input[3] = 0x01;
  // P1 = Algorithm identity
  input[4] = algo_id;
  // L1 = length of Algorithm identity 0x00 0x01
  input[5] = 0x00;
  input[6] = 0x01;

  /* Compute the derived key */
  kdf(kasme->value, kasme->length, input, 7, output, 32);
  memcpy(key->value, &output[31 - key->length + 1], key->length);
  return (RETURNok);
}