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 #include "epa.h"
  14
  15 // Protocol and Parameter Selection Request for ISO 14443 type A cards
  16 // use regular (1x) speed in both directions
  17 // CRC is already included
  18 static const uint8_t pps[] = {0xD0, 0x11, 0x00, 0x52, 0xA6};
  19
  20 // APDUs for communication with German Identification Card
  21
  22 // General Authenticate (request encrypted nonce) WITHOUT the Le at the end
  23 static const uint8_t apdu_general_authenticate_pace_get_nonce[] = {
  24         0x10, // CLA
  25         0x86, // INS
  26         0x00, // P1
  27         0x00, // P2
  28         0x02, // Lc
  29         0x7C, // Type: Dynamic Authentication Data
  30         0x00, // Length: 0 bytes
  31 };
  32
  33 // MSE: Set AT (only CLA, INS, P1 and P2)
  34 static const uint8_t apdu_mse_set_at_start[] = {
  35         0x00, // CLA
  36         0x22, // INS
  37         0xC1, // P1
  38         0xA4, // P2
  39 };
  40
  41 // SELECT BINARY with the ID for EF.CardAccess
  42 static const uint8_t apdu_select_binary_cardaccess[] = {
  43         0x00, // CLA
  44         0xA4, // INS
  45         0x02, // P1
  46         0x0C, // P2
  47         0x02, // Lc
  48         0x01, // ID
  49         0x1C  // ID
  50 };
  51
  52 // READ BINARY
  53 static const uint8_t apdu_read_binary[] = {
  54         0x00, // CLA
  55         0xB0, // INS
  56         0x00, // P1
  57         0x00, // P2
  58         0x38  // Le
  59 };
  60
  61
  62 // the leading bytes of a PACE OID
  63 static const uint8_t oid_pace_start[] = {
  64     0x04, // itu-t, identified-organization
  65     0x00, // etsi
  66     0x7F, // reserved
  67     0x00, // etsi-identified-organization
  68     0x07, // bsi-de
  69     0x02, // protocols
  70     0x02, // smartcard
  71     0x04 // id-PACE
  72 };
  73
  74 // APDUs for replaying:
  75 // MSE: Set AT (initiate PACE)
  76 static uint8_t apdu_replay_mse_set_at_pace[41];
  77 // General Authenticate (Get Nonce)
  78 static uint8_t apdu_replay_general_authenticate_pace_get_nonce[8];
  79 // General Authenticate (Map Nonce)
  80 static uint8_t apdu_replay_general_authenticate_pace_map_nonce[75];
  81 // General Authenticate (Mutual Authenticate)
  82 static uint8_t apdu_replay_general_authenticate_pace_mutual_authenticate[75];
  83 // General Authenticate (Perform Key Agreement)
  84 static uint8_t apdu_replay_general_authenticate_pace_perform_key_agreement[18];
  85 // pointers to the APDUs (for iterations)
  86 static struct {
  87         uint8_t len;
  88         uint8_t *data;
  89 } const apdus_replay[] = {
  90         {sizeof(apdu_replay_mse_set_at_pace), apdu_replay_mse_set_at_pace},
  91         {sizeof(apdu_replay_general_authenticate_pace_get_nonce), apdu_replay_general_authenticate_pace_get_nonce},
  92         {sizeof(apdu_replay_general_authenticate_pace_map_nonce), apdu_replay_general_authenticate_pace_map_nonce},
  93         {sizeof(apdu_replay_general_authenticate_pace_mutual_authenticate), apdu_replay_general_authenticate_pace_mutual_authenticate},
  94         {sizeof(apdu_replay_general_authenticate_pace_perform_key_agreement), apdu_replay_general_authenticate_pace_perform_key_agreement}
  95 };
  96
  97 // lengths of the replay APDUs
  98 static uint8_t apdu_lengths_replay[5];
  99
 100 // type of card (ISO 14443 A or B)
 101 static char iso_type;
 102
 103 //-----------------------------------------------------------------------------
 104 // Wrapper for sending APDUs to type A and B cards
 105 //-----------------------------------------------------------------------------
 106 int EPA_APDU(uint8_t *apdu, size_t length, uint8_t *response)
 107 {
 108         switch(iso_type)
 109         {
 110                 case 'a':
 111                         return iso14_apdu(apdu, (uint16_t) length, response);
 112                         break;
 113                 case 'b':
 114                         return iso14443b_apdu(apdu, length, response);
 115                         break;
 116                 default:
 117                         return 0;
 118                         break;
 119         }
 120 }
 121
 122 //-----------------------------------------------------------------------------
 123 // Closes the communication channel and turns off the field
 124 //-----------------------------------------------------------------------------
 125 void EPA_Finish()
 126 {
 127         FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 128         LEDsoff();
 129         iso_type = 0;
 130 }
 131
 132 //-----------------------------------------------------------------------------
 133 // Parses DER encoded data, e.g. from EF.CardAccess and fills out the given
 134 // structs. If a pointer is 0, it is ignored.
 135 // The function returns 0 on success and if an error occured, it returns the
 136 // offset where it occured.
 137 //
 138 // TODO: This function can access memory outside of the given data if the DER
 139 //       encoding is broken
 140 // TODO: Support skipping elements with a length > 0x7F
 141 // TODO: Support OIDs with a length > 7F
 142 // TODO: Support elements with long tags (tag is longer than 1 byte)
 143 // TODO: Support proprietary PACE domain parameters
 144 //-----------------------------------------------------------------------------
 145 size_t EPA_Parse_CardAccess(uint8_t *data,
 146                             size_t length,
 147                             pace_version_info_t *pace_info)
 148 {
 149         size_t index = 0;
 150
 151         while (index <= length - 2) {
 152                 // determine type of element
 153                 // SET or SEQUENCE
 154                 if (data[index] == 0x31 || data[index] == 0x30) {
 155                         // enter the set (skip tag + length)
 156                         index += 2;
 157                         // check for extended length
 158                         if ((data[index - 1] & 0x80) != 0) {
 159                                 index += (data[index-1] & 0x7F);
 160                         }
 161                 }
 162                 // OID
 163                 else if (data[index] == 0x06) {
 164                         // is this a PACE OID?
 165                         if (data[index + 1] == 0x0A // length matches
 166                             && memcmp(data + index + 2,
 167                                       oid_pace_start,
 168                                       sizeof(oid_pace_start)) == 0 // content matches
 169                             && pace_info != NULL)
 170                         {
 171                                 // first, clear the pace_info struct
 172                                 memset(pace_info, 0, sizeof(pace_version_info_t));
 173                                 memcpy(pace_info->oid, data + index + 2, sizeof(pace_info->oid));
 174                                 // a PACE OID is followed by the version
 175                                 index += data[index + 1] + 2;
 176                                 if (data[index] == 02 && data[index + 1] == 01) {
 177                                         pace_info->version = data[index + 2];
 178                                         index += 3;
 179                                 }
 180                                 else {
 181                                         return index;
 182                                 }
 183                                 // after that there might(!) be the parameter ID
 184                                 if (data[index] == 02 && data[index + 1] == 01) {
 185                                         pace_info->parameter_id = data[index + 2];
 186                                         index += 3;
 187                                 }
 188                         }
 189                         else {
 190                                 // skip this OID
 191                                 index += 2 + data[index + 1];
 192                         }
 193                 }
 194                 // if the length is 0, something is wrong
 195                 // TODO: This needs to be extended to support long tags
 196                 else if (data[index + 1] == 0) {
 197                         return index;
 198                 }
 199                 else {
 200                         // skip this part
 201                         // TODO: This needs to be extended to support long tags
 202                         // TODO: This needs to be extended to support unknown elements with
 203                         //       a size > 0x7F
 204                         index += 2 + data[index + 1];
 205                 }
 206         }
 207
 208         // TODO: We should check whether we reached the end in error, but for that
 209         //       we need a better parser (e.g. with states like IN_SET or IN_PACE_INFO)
 210         return 0;
 211 }
 212
 213 //-----------------------------------------------------------------------------
 214 // Read the file EF.CardAccess and save it into a buffer (at most max_length bytes)
 215 // Returns -1 on failure or the length of the data on success
 216 // TODO: for the moment this sends only 1 APDU regardless of the requested length
 217 //-----------------------------------------------------------------------------
 218 int EPA_Read_CardAccess(uint8_t *buffer, size_t max_length)
 219 {
 220         // the response APDU of the card
 221         // since the card doesn't always care for the expected length we send it,
 222         // we reserve 262 bytes here just to be safe (256-byte APDU + SW + ISO frame)
 223         uint8_t response_apdu[262];
 224         int rapdu_length = 0;
 225
 226         // select the file EF.CardAccess
 227         rapdu_length = EPA_APDU((uint8_t *)apdu_select_binary_cardaccess,
 228                                   sizeof(apdu_select_binary_cardaccess),
 229                                   response_apdu);
 230         if (rapdu_length < 6
 231             || response_apdu[rapdu_length - 4] != 0x90
 232             || response_apdu[rapdu_length - 3] != 0x00)
 233         {
 234                 DbpString("Failed to select EF.CardAccess!");
 235                 return -1;
 236         }
 237
 238         // read the file
 239         rapdu_length = EPA_APDU((uint8_t *)apdu_read_binary,
 240                                   sizeof(apdu_read_binary),
 241                                   response_apdu);
 242         if (rapdu_length <= 6
 243             || response_apdu[rapdu_length - 4] != 0x90
 244             || response_apdu[rapdu_length - 3] != 0x00)
 245         {
 246                 Dbprintf("Failed to read EF.CardAccess!");
 247                 return -1;
 248         }
 249
 250         // copy the content into the buffer
 251         // length of data available: apdu_length - 4 (ISO frame) - 2 (SW)
 252         size_t to_copy = rapdu_length - 6;
 253         to_copy = to_copy < max_length ? to_copy : max_length;
 254         memcpy(buffer, response_apdu+2, to_copy);
 255         return to_copy;
 256 }
 257
 258 //-----------------------------------------------------------------------------
 259 // Abort helper function for EPA_PACE_Collect_Nonce
 260 // sets relevant data in ack, sends the response
 261 //-----------------------------------------------------------------------------
 262 static void EPA_PACE_Collect_Nonce_Abort(uint8_t step, int func_return)
 263 {
 264         // power down the field
 265         EPA_Finish();
 266
 267         // send the USB packet
 268         cmd_send(CMD_ACK,step,func_return,0,0,0);
 269 }
 270
 271 //-----------------------------------------------------------------------------
 272 // Acquire one encrypted PACE nonce
 273 //-----------------------------------------------------------------------------
 274 void EPA_PACE_Collect_Nonce(UsbCommand *c)
 275 {
 276         /*
 277          * ack layout:
 278          *      arg:
 279          *              1. element
 280          *           step where the error occured or 0 if no error occured
 281      *       2. element
 282      *           return code of the last executed function
 283          *      d:
 284          *              Encrypted nonce
 285          */
 286
 287         // return value of a function
 288         int func_return = 0;
 289
 290         // set up communication
 291         func_return = EPA_Setup();
 292         if (func_return != 0) {
 293                 EPA_PACE_Collect_Nonce_Abort(1, func_return);
 294                 return;
 295         }
 296
 297         // read the CardAccess file
 298         // this array will hold the CardAccess file
 299         uint8_t card_access[256] = {0};
 300         int card_access_length = EPA_Read_CardAccess(card_access, 256);
 301         // the response has to be at least this big to hold the OID
 302         if (card_access_length < 18) {
 303                 EPA_PACE_Collect_Nonce_Abort(2, card_access_length);
 304                 return;
 305         }
 306
 307         // this will hold the PACE info of the card
 308         pace_version_info_t pace_version_info;
 309         // search for the PACE OID
 310         func_return = EPA_Parse_CardAccess(card_access,
 311                                            card_access_length,
 312                                            &pace_version_info);
 313         if (func_return != 0 || pace_version_info.version == 0) {
 314                 EPA_PACE_Collect_Nonce_Abort(3, func_return);
 315                 return;
 316         }
 317
 318         // initiate the PACE protocol
 319         // use the CAN for the password since that doesn't change
 320         func_return = EPA_PACE_MSE_Set_AT(pace_version_info, 2);
 321
 322         // now get the nonce
 323         uint8_t nonce[256] = {0};
 324         uint8_t requested_size = (uint8_t)c->arg[0];
 325         func_return = EPA_PACE_Get_Nonce(requested_size, nonce);
 326         // check if the command succeeded
 327         if (func_return < 0)
 328         {
 329                 EPA_PACE_Collect_Nonce_Abort(4, func_return);
 330                 return;
 331         }
 332
 333         // all done, return
 334         EPA_Finish();
 335
 336         // save received information
 337         cmd_send(CMD_ACK,0,func_return,0,nonce,func_return);
 338 }
 339
 340 //-----------------------------------------------------------------------------
 341 // Performs the "Get Nonce" step of the PACE protocol and saves the returned
 342 // nonce. The caller is responsible for allocating enough memory to store the
 343 // nonce. Note that the returned size might be less or than or greater than the
 344 // requested size!
 345 // Returns the actual size of the nonce on success or a less-than-zero error
 346 // code on failure.
 347 //-----------------------------------------------------------------------------
 348 int EPA_PACE_Get_Nonce(uint8_t requested_length, uint8_t *nonce)
 349 {
 350         // build the APDU
 351         uint8_t apdu[sizeof(apdu_general_authenticate_pace_get_nonce) + 1];
 352         // copy the constant part
 353         memcpy(apdu,
 354                apdu_general_authenticate_pace_get_nonce,
 355                sizeof(apdu_general_authenticate_pace_get_nonce));
 356         // append Le (requested length + 2 due to tag/length taking 2 bytes) in RAPDU
 357         apdu[sizeof(apdu_general_authenticate_pace_get_nonce)] = requested_length + 4;
 358
 359         // send it
 360         uint8_t response_apdu[262];
 361         int send_return = EPA_APDU(apdu,
 362                                      sizeof(apdu),
 363                                      response_apdu);
 364         // check if the command succeeded
 365         if (send_return < 6
 366                 || response_apdu[send_return - 4] != 0x90
 367                 || response_apdu[send_return - 3] != 0x00)
 368         {
 369                 return -1;
 370         }
 371
 372         // if there is no nonce in the RAPDU, return here
 373         if (send_return < 10)
 374         {
 375                 // no error
 376                 return 0;
 377         }
 378         // get the actual length of the nonce
 379         uint8_t nonce_length = response_apdu[5];
 380         if (nonce_length > send_return - 10)
 381         {
 382                 nonce_length = send_return - 10;
 383         }
 384         // copy the nonce
 385         memcpy(nonce, response_apdu + 6, nonce_length);
 386
 387         return nonce_length;
 388 }
 389
 390 //-----------------------------------------------------------------------------
 391 // Initializes the PACE protocol by performing the "MSE: Set AT" step
 392 // Returns 0 on success or a non-zero error code on failure
 393 //-----------------------------------------------------------------------------
 394 int EPA_PACE_MSE_Set_AT(pace_version_info_t pace_version_info, uint8_t password)
 395 {
 396         // create the MSE: Set AT APDU
 397         uint8_t apdu[23];
 398         // the minimum length (will be increased as more data is added)
 399         size_t apdu_length = 20;
 400         // copy the constant part
 401         memcpy(apdu,
 402                apdu_mse_set_at_start,
 403                sizeof(apdu_mse_set_at_start));
 404         // type: OID
 405         apdu[5] = 0x80;
 406         // length of the OID
 407         apdu[6] = sizeof(pace_version_info.oid);
 408         // copy the OID
 409         memcpy(apdu + 7,
 410                pace_version_info.oid,
 411                sizeof(pace_version_info.oid));
 412         // type: password
 413         apdu[17] = 0x83;
 414         // length: 1
 415         apdu[18] = 1;
 416         // password
 417         apdu[19] = password;
 418         // if standardized domain parameters are used, copy the ID
 419         if (pace_version_info.parameter_id != 0) {
 420                 apdu_length += 3;
 421                 // type: domain parameter
 422                 apdu[20] = 0x84;
 423                 // length: 1
 424                 apdu[21] = 1;
 425                 // copy the parameter ID
 426                 apdu[22] = pace_version_info.parameter_id;
 427         }
 428         // now set Lc to the actual length
 429         apdu[4] = apdu_length - 5;
 430         // send it
 431         uint8_t response_apdu[6];
 432         int send_return = EPA_APDU(apdu,
 433                                      apdu_length,
 434                                      response_apdu);
 435         // check if the command succeeded
 436         if (send_return != 6
 437                 || response_apdu[send_return - 4] != 0x90
 438                 || response_apdu[send_return - 3] != 0x00)
 439         {
 440                 return 1;
 441         }
 442         return 0;
 443 }
 444
 445 //-----------------------------------------------------------------------------
 446 // Perform the PACE protocol by replaying given APDUs
 447 //-----------------------------------------------------------------------------
 448 void EPA_PACE_Replay(UsbCommand *c)
 449 {
 450         uint32_t timings[sizeof(apdu_lengths_replay) / sizeof(apdu_lengths_replay[0])] = {0};
 451
 452         // if an APDU has been passed, save it
 453         if (c->arg[0] != 0) {
 454                 // make sure it's not too big
 455                 if(c->arg[2] > apdus_replay[c->arg[0] - 1].len)
 456                 {
 457                         cmd_send(CMD_ACK, 1, 0, 0, NULL, 0);
 458                 }
 459                 memcpy(apdus_replay[c->arg[0] - 1].data + c->arg[1],
 460                    c->d.asBytes,
 461                    c->arg[2]);
 462                 // save/update APDU length
 463                 if (c->arg[1] == 0) {
 464                         apdu_lengths_replay[c->arg[0] - 1] = c->arg[2];
 465                 } else {
 466                         apdu_lengths_replay[c->arg[0] - 1] += c->arg[2];
 467                 }
 468                 cmd_send(CMD_ACK, 0, 0, 0, NULL, 0);
 469                 return;
 470         }
 471
 472         // return value of a function
 473         int func_return;
 474
 475         // set up communication
 476         func_return = EPA_Setup();
 477         if (func_return != 0) {
 478                 EPA_Finish();
 479                 cmd_send(CMD_ACK, 2, func_return, 0, NULL, 0);
 480                 return;
 481         }
 482
 483         // increase the timeout (at least some cards really do need this!)/////////////
 484         // iso14a_set_timeout(0x0003FFFF);
 485
 486         // response APDU
 487         uint8_t response_apdu[300] = {0};
 488
 489         // now replay the data and measure the timings
 490         for (int i = 0; i < sizeof(apdu_lengths_replay); i++) {
 491                 StartCountUS();
 492                 func_return = EPA_APDU(apdus_replay[i].data,
 493                                          apdu_lengths_replay[i],
 494                                          response_apdu);
 495                 timings[i] = GetCountUS();
 496                 // every step but the last one should succeed
 497                 if (i < sizeof(apdu_lengths_replay) - 1
 498                     && (func_return < 6
 499                         || response_apdu[func_return - 4] != 0x90
 500                         || response_apdu[func_return - 3] != 0x00))
 501                 {
 502                         EPA_Finish();
 503                         cmd_send(CMD_ACK, 3 + i, func_return, 0, timings, 20);
 504                         return;
 505                 }
 506         }
 507         EPA_Finish();
 508         cmd_send(CMD_ACK,0,0,0,timings,20);
 509         return;
 510 }
 511
 512 //-----------------------------------------------------------------------------
 513 // Set up a communication channel (Card Select, PPS)
 514 // Returns 0 on success or a non-zero error code on failure
 515 //-----------------------------------------------------------------------------
 516 int EPA_Setup()
 517 {
 518         int return_code = 0;
 519         uint8_t uid[10];
 520         uint8_t pps_response[3];
 521         uint8_t pps_response_par[1];
 522         iso14a_card_select_t card_a_info;
 523         iso14b_card_select_t card_b_info;
 524
 525         // first, look for type A cards
 526         // power up the field
 527         iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
 528         // select the card
 529         return_code = iso14443a_select_card(uid, &card_a_info, NULL, true, 0);
 530         if (return_code == 1) {
 531                 // send the PPS request
 532                 ReaderTransmit((uint8_t *)pps, sizeof(pps), NULL);
 533                 return_code = ReaderReceive(pps_response, pps_response_par);
 534                 if (return_code != 3 || pps_response[0] != 0xD0) {
 535                         return return_code == 0 ? 2 : return_code;
 536                 }
 537                 Dbprintf("ISO 14443 Type A");
 538                 iso_type = 'a';
 539                 return 0;
 540         }
 541
 542         // if we're here, there is no type A card, so we look for type B
 543         // power up the field
 544         iso14443b_setup();
 545         // select the card
 546         return_code = iso14443b_select_card( &card_b_info );
 547         if (return_code == 1) {
 548                 Dbprintf("ISO 14443 Type B");
 549                 iso_type = 'b';
 550                 return 0;
 551         }
 552         Dbprintf("No card found.");
 553         return 1;
 554 }