git.zerfleddert.de Git - proxmark3-svn/blob - armsrc/epa.c

   1 //-----------------------------------------------------------------------------
   2 // Frederik Möllers - August 2012
   3 //
   4 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
   5 // at your option, any later version. See the LICENSE.txt file for the text of
   6 // the license.
   7 //-----------------------------------------------------------------------------
   8 // Routines to support the German electronic "Personalausweis" (ID card)
   9 // Note that the functions which do not implement USB commands do NOT initialize
  10 // the card (with iso14443a_select_card etc.). If You want to use these
  11 // functions, You need to do the setup before calling them!
  12 //-----------------------------------------------------------------------------
  13
  14 #include "apps.h"
  15 #include "iso14443a.h"
  16 #include "iso14443b.h"
  17 #include "epa.h"
  18 #include "usb_cdc.h"
  19 #include "fpgaloader.h"
  20 #include "string.h"
  21 #include "util.h"
  22
  23 // Protocol and Parameter Selection Request for ISO 14443 type A cards
  24 // use regular (1x) speed in both directions
  25 // CRC is already included
  26 static const uint8_t pps[] = {0xD0, 0x11, 0x00, 0x52, 0xA6};
  27
  28 // APDUs for communication with German Identification Card
  29
  30 // General Authenticate (request encrypted nonce) WITHOUT the Le at the end
  31 static const uint8_t apdu_general_authenticate_pace_get_nonce[] = {
  32         0x10, // CLA
  33         0x86, // INS
  34         0x00, // P1
  35         0x00, // P2
  36         0x02, // Lc
  37         0x7C, // Type: Dynamic Authentication Data
  38         0x00, // Length: 0 bytes
  39 };
  40
  41 // MSE: Set AT (only CLA, INS, P1 and P2)
  42 static const uint8_t apdu_mse_set_at_start[] = {
  43         0x00, // CLA
  44         0x22, // INS
  45         0xC1, // P1
  46         0xA4, // P2
  47 };
  48
  49 // SELECT BINARY with the ID for EF.CardAccess
  50 static const uint8_t apdu_select_binary_cardaccess[] = {
  51         0x00, // CLA
  52         0xA4, // INS
  53         0x02, // P1
  54         0x0C, // P2
  55         0x02, // Lc
  56         0x01, // ID
  57         0x1C  // ID
  58 };
  59
  60 // READ BINARY
  61 static const uint8_t apdu_read_binary[] = {
  62         0x00, // CLA
  63         0xB0, // INS
  64         0x00, // P1
  65         0x00, // P2
  66         0x38  // Le
  67 };
  68
  69
  70 // the leading bytes of a PACE OID
  71 static const uint8_t oid_pace_start[] = {
  72     0x04, // itu-t, identified-organization
  73     0x00, // etsi
  74     0x7F, // reserved
  75     0x00, // etsi-identified-organization
  76     0x07, // bsi-de
  77     0x02, // protocols
  78     0x02, // smartcard
  79     0x04 // id-PACE
  80 };
  81
  82 // APDUs for replaying:
  83 // MSE: Set AT (initiate PACE)
  84 static uint8_t apdu_replay_mse_set_at_pace[41];
  85 // General Authenticate (Get Nonce)
  86 static uint8_t apdu_replay_general_authenticate_pace_get_nonce[8];
  87 // General Authenticate (Map Nonce)
  88 static uint8_t apdu_replay_general_authenticate_pace_map_nonce[75];
  89 // General Authenticate (Mutual Authenticate)
  90 static uint8_t apdu_replay_general_authenticate_pace_mutual_authenticate[75];
  91 // General Authenticate (Perform Key Agreement)
  92 static uint8_t apdu_replay_general_authenticate_pace_perform_key_agreement[18];
  93 // pointers to the APDUs (for iterations)
  94 static struct {
  95         uint8_t len;
  96         uint8_t *data;
  97 } const apdus_replay[] = {
  98         {sizeof(apdu_replay_mse_set_at_pace), apdu_replay_mse_set_at_pace},
  99         {sizeof(apdu_replay_general_authenticate_pace_get_nonce), apdu_replay_general_authenticate_pace_get_nonce},
 100         {sizeof(apdu_replay_general_authenticate_pace_map_nonce), apdu_replay_general_authenticate_pace_map_nonce},
 101         {sizeof(apdu_replay_general_authenticate_pace_mutual_authenticate), apdu_replay_general_authenticate_pace_mutual_authenticate},
 102         {sizeof(apdu_replay_general_authenticate_pace_perform_key_agreement), apdu_replay_general_authenticate_pace_perform_key_agreement}
 103 };
 104
 105 // lengths of the replay APDUs
 106 static uint8_t apdu_lengths_replay[5];
 107
 108 // type of card (ISO 14443 A or B)
 109 static char iso_type = 0;
 110
 111 //-----------------------------------------------------------------------------
 112 // Wrapper for sending APDUs to type A and B cards
 113 //-----------------------------------------------------------------------------
 114 int EPA_APDU(uint8_t *apdu, size_t length, uint8_t *response)
 115 {
 116         switch(iso_type)
 117         {
 118                 case 'a':
 119                         return iso14_apdu(apdu, (uint16_t) length, false, response, NULL);
 120                         break;
 121                 case 'b':
 122                         return iso14443b_apdu(apdu, length, response);
 123                         break;
 124                 default:
 125                         return 0;
 126                         break;
 127         }
 128 }
 129
 130 //-----------------------------------------------------------------------------
 131 // Closes the communication channel and turns off the field
 132 //-----------------------------------------------------------------------------
 133 void EPA_Finish()
 134 {
 135         FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 136         LEDsoff();
 137         iso_type = 0;
 138 }
 139
 140 //-----------------------------------------------------------------------------
 141 // Parses DER encoded data, e.g. from EF.CardAccess and fills out the given
 142 // structs. If a pointer is 0, it is ignored.
 143 // The function returns 0 on success and if an error occured, it returns the
 144 // offset where it occured.
 145 //
 146 // TODO: This function can access memory outside of the given data if the DER
 147 //       encoding is broken
 148 // TODO: Support skipping elements with a length > 0x7F
 149 // TODO: Support OIDs with a length > 7F
 150 // TODO: Support elements with long tags (tag is longer than 1 byte)
 151 // TODO: Support proprietary PACE domain parameters
 152 //-----------------------------------------------------------------------------
 153 size_t EPA_Parse_CardAccess(uint8_t *data,
 154                             size_t length,
 155                             pace_version_info_t *pace_info)
 156 {
 157         size_t index = 0;
 158
 159         while (index <= length - 2) {
 160                 // determine type of element
 161                 // SET or SEQUENCE
 162                 if (data[index] == 0x31 || data[index] == 0x30) {
 163                         // enter the set (skip tag + length)
 164                         index += 2;
 165                         // check for extended length
 166                         if ((data[index - 1] & 0x80) != 0) {
 167                                 index += (data[index-1] & 0x7F);
 168                         }
 169                 }
 170                 // OID
 171                 else if (data[index] == 0x06) {
 172                         // is this a PACE OID?
 173                         if (data[index + 1] == 0x0A // length matches
 174                             && memcmp(data + index + 2,
 175                                       oid_pace_start,
 176                                       sizeof(oid_pace_start)) == 0 // content matches
 177                             && pace_info != NULL)
 178                         {
 179                                 // first, clear the pace_info struct
 180                                 memset(pace_info, 0, sizeof(pace_version_info_t));
 181                                 memcpy(pace_info->oid, data + index + 2, sizeof(pace_info->oid));
 182                                 // a PACE OID is followed by the version
 183                                 index += data[index + 1] + 2;
 184                                 if (data[index] == 02 && data[index + 1] == 01) {
 185                                         pace_info->version = data[index + 2];
 186                                         index += 3;
 187                                 }
 188                                 else {
 189                                         return index;
 190                                 }
 191                                 // after that there might(!) be the parameter ID
 192                                 if (data[index] == 02 && data[index + 1] == 01) {
 193                                         pace_info->parameter_id = data[index + 2];
 194                                         index += 3;
 195                                 }
 196                         }
 197                         else {
 198                                 // skip this OID
 199                                 index += 2 + data[index + 1];
 200                         }
 201                 }
 202                 // if the length is 0, something is wrong
 203                 // TODO: This needs to be extended to support long tags
 204                 else if (data[index + 1] == 0) {
 205                         return index;
 206                 }
 207                 else {
 208                         // skip this part
 209                         // TODO: This needs to be extended to support long tags
 210                         // TODO: This needs to be extended to support unknown elements with
 211                         //       a size > 0x7F
 212                         index += 2 + data[index + 1];
 213                 }
 214         }
 215
 216         // TODO: We should check whether we reached the end in error, but for that
 217         //       we need a better parser (e.g. with states like IN_SET or IN_PACE_INFO)
 218         return 0;
 219 }
 220
 221 //-----------------------------------------------------------------------------
 222 // Read the file EF.CardAccess and save it into a buffer (at most max_length bytes)
 223 // Returns -1 on failure or the length of the data on success
 224 // TODO: for the moment this sends only 1 APDU regardless of the requested length
 225 //-----------------------------------------------------------------------------
 226 int EPA_Read_CardAccess(uint8_t *buffer, size_t max_length)
 227 {
 228         // the response APDU of the card
 229         // since the card doesn't always care for the expected length we send it,
 230         // we reserve 262 bytes here just to be safe (256-byte APDU + SW + ISO frame)
 231         uint8_t response_apdu[262];
 232         int rapdu_length = 0;
 233
 234         // select the file EF.CardAccess
 235         rapdu_length = EPA_APDU((uint8_t *)apdu_select_binary_cardaccess,
 236                                   sizeof(apdu_select_binary_cardaccess),
 237                                   response_apdu);
 238         if (rapdu_length < 6
 239             || response_apdu[rapdu_length - 4] != 0x90
 240             || response_apdu[rapdu_length - 3] != 0x00)
 241         {
 242                 DbpString("Failed to select EF.CardAccess!");
 243                 return -1;
 244         }
 245
 246         // read the file
 247         rapdu_length = EPA_APDU((uint8_t *)apdu_read_binary,
 248                                   sizeof(apdu_read_binary),
 249                                   response_apdu);
 250         if (rapdu_length <= 6
 251             || response_apdu[rapdu_length - 4] != 0x90
 252             || response_apdu[rapdu_length - 3] != 0x00)
 253         {
 254                 Dbprintf("Failed to read EF.CardAccess!");
 255                 return -1;
 256         }
 257
 258         // copy the content into the buffer
 259         // length of data available: apdu_length - 4 (ISO frame) - 2 (SW)
 260         size_t to_copy = rapdu_length - 6;
 261         to_copy = to_copy < max_length ? to_copy : max_length;
 262         memcpy(buffer, response_apdu+2, to_copy);
 263         return to_copy;
 264 }
 265
 266 //-----------------------------------------------------------------------------
 267 // Abort helper function for EPA_PACE_Collect_Nonce
 268 // sets relevant data in ack, sends the response
 269 //-----------------------------------------------------------------------------
 270 static void EPA_PACE_Collect_Nonce_Abort(uint8_t step, int func_return)
 271 {
 272         // power down the field
 273         EPA_Finish();
 274
 275         // send the USB packet
 276         cmd_send(CMD_ACK,step,func_return,0,0,0);
 277 }
 278
 279 //-----------------------------------------------------------------------------
 280 // Acquire one encrypted PACE nonce
 281 //-----------------------------------------------------------------------------
 282 void EPA_PACE_Collect_Nonce(UsbCommand *c)
 283 {
 284         /*
 285          * ack layout:
 286          *      arg:
 287          *              1. element
 288          *           step where the error occured or 0 if no error occured
 289      *       2. element
 290      *           return code of the last executed function
 291          *      d:
 292          *              Encrypted nonce
 293          */
 294
 295         // return value of a function
 296         int func_return = 0;
 297
 298         // set up communication
 299         func_return = EPA_Setup();
 300         if (func_return != 0) {
 301                 EPA_PACE_Collect_Nonce_Abort(1, func_return);
 302                 return;
 303         }
 304
 305         // read the CardAccess file
 306         // this array will hold the CardAccess file
 307         uint8_t card_access[256] = {0};
 308         int card_access_length = EPA_Read_CardAccess(card_access, 256);
 309         // the response has to be at least this big to hold the OID
 310         if (card_access_length < 18) {
 311                 EPA_PACE_Collect_Nonce_Abort(2, card_access_length);
 312                 return;
 313         }
 314
 315         // this will hold the PACE info of the card
 316         pace_version_info_t pace_version_info;
 317         // search for the PACE OID
 318         func_return = EPA_Parse_CardAccess(card_access,
 319                                            card_access_length,
 320                                            &pace_version_info);
 321         if (func_return != 0 || pace_version_info.version == 0) {
 322                 EPA_PACE_Collect_Nonce_Abort(3, func_return);
 323                 return;
 324         }
 325
 326         // initiate the PACE protocol
 327         // use the CAN for the password since that doesn't change
 328         func_return = EPA_PACE_MSE_Set_AT(pace_version_info, 2);
 329
 330         // now get the nonce
 331         uint8_t nonce[256] = {0};
 332         uint8_t requested_size = (uint8_t)c->arg[0];
 333         func_return = EPA_PACE_Get_Nonce(requested_size, nonce);
 334         // check if the command succeeded
 335         if (func_return < 0)
 336         {
 337                 EPA_PACE_Collect_Nonce_Abort(4, func_return);
 338                 return;
 339         }
 340
 341         // all done, return
 342         EPA_Finish();
 343
 344         // save received information
 345         cmd_send(CMD_ACK,0,func_return,0,nonce,func_return);
 346 }
 347
 348 //-----------------------------------------------------------------------------
 349 // Performs the "Get Nonce" step of the PACE protocol and saves the returned
 350 // nonce. The caller is responsible for allocating enough memory to store the
 351 // nonce. Note that the returned size might be less or than or greater than the
 352 // requested size!
 353 // Returns the actual size of the nonce on success or a less-than-zero error
 354 // code on failure.
 355 //-----------------------------------------------------------------------------
 356 int EPA_PACE_Get_Nonce(uint8_t requested_length, uint8_t *nonce)
 357 {
 358         // build the APDU
 359         uint8_t apdu[sizeof(apdu_general_authenticate_pace_get_nonce) + 1];
 360         // copy the constant part
 361         memcpy(apdu,
 362                apdu_general_authenticate_pace_get_nonce,
 363                sizeof(apdu_general_authenticate_pace_get_nonce));
 364         // append Le (requested length + 2 due to tag/length taking 2 bytes) in RAPDU
 365         apdu[sizeof(apdu_general_authenticate_pace_get_nonce)] = requested_length + 4;
 366
 367         // send it
 368         uint8_t response_apdu[262];
 369         int send_return = EPA_APDU(apdu,
 370                                      sizeof(apdu),
 371                                      response_apdu);
 372         // check if the command succeeded
 373         if (send_return < 6
 374                 || response_apdu[send_return - 4] != 0x90
 375                 || response_apdu[send_return - 3] != 0x00)
 376         {
 377                 return -1;
 378         }
 379
 380         // if there is no nonce in the RAPDU, return here
 381         if (send_return < 10)
 382         {
 383                 // no error
 384                 return 0;
 385         }
 386         // get the actual length of the nonce
 387         uint8_t nonce_length = response_apdu[5];
 388         if (nonce_length > send_return - 10)
 389         {
 390                 nonce_length = send_return - 10;
 391         }
 392         // copy the nonce
 393         memcpy(nonce, response_apdu + 6, nonce_length);
 394
 395         return nonce_length;
 396 }
 397
 398 //-----------------------------------------------------------------------------
 399 // Initializes the PACE protocol by performing the "MSE: Set AT" step
 400 // Returns 0 on success or a non-zero error code on failure
 401 //-----------------------------------------------------------------------------
 402 int EPA_PACE_MSE_Set_AT(pace_version_info_t pace_version_info, uint8_t password)
 403 {
 404         // create the MSE: Set AT APDU
 405         uint8_t apdu[23];
 406         // the minimum length (will be increased as more data is added)
 407         size_t apdu_length = 20;
 408         // copy the constant part
 409         memcpy(apdu,
 410                apdu_mse_set_at_start,
 411                sizeof(apdu_mse_set_at_start));
 412         // type: OID
 413         apdu[5] = 0x80;
 414         // length of the OID
 415         apdu[6] = sizeof(pace_version_info.oid);
 416         // copy the OID
 417         memcpy(apdu + 7,
 418                pace_version_info.oid,
 419                sizeof(pace_version_info.oid));
 420         // type: password
 421         apdu[17] = 0x83;
 422         // length: 1
 423         apdu[18] = 1;
 424         // password
 425         apdu[19] = password;
 426         // if standardized domain parameters are used, copy the ID
 427         if (pace_version_info.parameter_id != 0) {
 428                 apdu_length += 3;
 429                 // type: domain parameter
 430                 apdu[20] = 0x84;
 431                 // length: 1
 432                 apdu[21] = 1;
 433                 // copy the parameter ID
 434                 apdu[22] = pace_version_info.parameter_id;
 435         }
 436         // now set Lc to the actual length
 437         apdu[4] = apdu_length - 5;
 438         // send it
 439         uint8_t response_apdu[6];
 440         int send_return = EPA_APDU(apdu,
 441                                      apdu_length,
 442                                      response_apdu);
 443         // check if the command succeeded
 444         if (send_return != 6
 445                 || response_apdu[send_return - 4] != 0x90
 446                 || response_apdu[send_return - 3] != 0x00)
 447         {
 448                 return 1;
 449         }
 450         return 0;
 451 }
 452
 453 //-----------------------------------------------------------------------------
 454 // Perform the PACE protocol by replaying given APDUs
 455 //-----------------------------------------------------------------------------
 456 void EPA_PACE_Replay(UsbCommand *c) {
 457         uint32_t timings[sizeof(apdu_lengths_replay) / sizeof(apdu_lengths_replay[0])] = {0};
 458
 459         // if an APDU has been passed, just save it
 460         if (c->arg[0] != 0) {
 461                 // make sure it's not too big
 462                 if(c->arg[2] > apdus_replay[c->arg[0] - 1].len) {
 463                         cmd_send(CMD_ACK, 1, 0, 0, NULL, 0);
 464                         return;
 465                 }
 466                 memcpy(apdus_replay[c->arg[0] - 1].data + c->arg[1], c->d.asBytes, c->arg[2]);
 467                 // save/update APDU length
 468                 if (c->arg[1] == 0) {
 469                         apdu_lengths_replay[c->arg[0] - 1] = c->arg[2];
 470                 } else {
 471                         apdu_lengths_replay[c->arg[0] - 1] += c->arg[2];
 472                 }
 473                 cmd_send(CMD_ACK, 0, 0, 0, NULL, 0);
 474                 return;
 475         }
 476
 477         // return value of a function
 478         int func_return;
 479
 480         // set up communication
 481         func_return = EPA_Setup();
 482         if (func_return != 0) {
 483                 EPA_Finish();
 484                 cmd_send(CMD_ACK, 2, func_return, 0, NULL, 0);
 485                 return;
 486         }
 487
 488         // response APDU
 489         uint8_t response_apdu[300] = {0};
 490
 491         // now replay the data and measure the timings
 492         for (int i = 0; i < sizeof(apdu_lengths_replay); i++) {
 493                 StartCountUS();
 494                 func_return = EPA_APDU(apdus_replay[i].data,
 495                                          apdu_lengths_replay[i],
 496                                          response_apdu);
 497                 timings[i] = GetCountUS();
 498                 // every step but the last one should succeed
 499                 if (i < sizeof(apdu_lengths_replay) - 1
 500                     && (func_return < 6
 501                         || response_apdu[func_return - 4] != 0x90
 502                         || response_apdu[func_return - 3] != 0x00))
 503                 {
 504                         EPA_Finish();
 505                         cmd_send(CMD_ACK, 3 + i, func_return, 0, timings, 20);
 506                         return;
 507                 }
 508         }
 509         EPA_Finish();
 510         cmd_send(CMD_ACK,0,0,0,timings,20);
 511         return;
 512 }
 513
 514 //-----------------------------------------------------------------------------
 515 // Set up a communication channel (Card Select, PPS)
 516 // Returns 0 on success or a non-zero error code on failure
 517 //-----------------------------------------------------------------------------
 518 int EPA_Setup()
 519 {
 520         int return_code = 0;
 521         uint8_t uid[10];
 522         uint8_t pps_response[3];
 523         uint8_t pps_response_par[1];
 524         iso14a_card_select_t card_select_info;
 525
 526         // first, look for type A cards
 527         // power up the field
 528         iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
 529         // select the card
 530         return_code = iso14443a_select_card(uid, &card_select_info, NULL, true, 0, false);
 531         if (return_code == 1) {
 532                 // send the PPS request
 533                 ReaderTransmit((uint8_t *)pps, sizeof(pps), NULL);
 534                 return_code = ReaderReceive(pps_response, pps_response_par);
 535                 if (return_code != 3 || pps_response[0] != 0xD0) {
 536                         return return_code == 0 ? 2 : return_code;
 537                 }
 538                 Dbprintf("ISO 14443 Type A");
 539                 iso_type = 'a';
 540                 return 0;
 541         }
 542
 543         // if we're here, there is no type A card, so we look for type B
 544         // power up the field
 545         iso14443b_setup();
 546         // select the card
 547         return_code = iso14443b_select_card();
 548         if (return_code == 1) {
 549                 Dbprintf("ISO 14443 Type B");
 550                 iso_type = 'b';
 551                 return 0;
 552         }
 553         Dbprintf("No card found.");
 554         return 1;
 555 }