cvs.zerfleddert.de Git - proxmark3-svn/blob - client/cmdhflegic.c

   1 //-----------------------------------------------------------------------------
   2 // Copyright (C) 2010 iZsh <izsh at fail0verflow.com>
   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 // High frequency Legic commands
   9 //-----------------------------------------------------------------------------
  10 #include "cmdhflegic.h"
  11
  12 static int CmdHelp(const char *Cmd);
  13
  14 int usage_legic_calccrc8(void){
  15         PrintAndLog("Calculates the legic crc8/crc16 on the input hexbytes.");
  16         PrintAndLog("There must be an even number of hexsymbols as input.");
  17         PrintAndLog("Usage:  hf legic crc8 [h] b <hexbytes> u <uidcrc> c <crc type>");
  18         PrintAndLog("Options:");
  19         PrintAndLog("      b <hexbytes>  : hex bytes");
  20         PrintAndLog("      u <uidcrc>    : MCC hexbyte");
  21         PrintAndLog("      c <crc type>  : 8|16 bit crc size");
  22         PrintAndLog("");
  23         PrintAndLog("Samples:");
  24         PrintAndLog("      hf legic crc8 b deadbeef1122");
  25         PrintAndLog("      hf legic crc8 b deadbeef1122 u 9A c 16");
  26         return 0;
  27 }
  28
  29 int usage_legic_load(void){
  30         PrintAndLog("It loads datasamples from the file `filename` to device memory");
  31         PrintAndLog("Usage:  hf legic load <file name>");
  32         PrintAndLog("");
  33         PrintAndLog("Samples:");
  34         PrintAndLog("      hf legic load filename");
  35         return 0;
  36 }
  37
  38 int usage_legic_read(void){
  39         PrintAndLog("Read data from a legic tag.");
  40         PrintAndLog("Usage:  hf legic read <offset> <num of bytes>");
  41         PrintAndLog("Options:");
  42         PrintAndLog("  <offset>        : offset in data array to start download from");
  43         PrintAndLog("  <num of bytes>  : number of bytes to download");
  44         PrintAndLog("");
  45         PrintAndLog("Samples:");
  46         PrintAndLog("      hf legic read");
  47         return 0;
  48 }
  49
  50 int usage_legic_sim(void){
  51         return 0;
  52 }
  53 int usage_legic_rawwrite(void){
  54         return 0;
  55 }
  56 int usage_legic_fill(void){
  57         return 0;
  58 }
  59
  60 /*
  61  *  Output BigBuf and deobfuscate LEGIC RF tag data.
  62  *  This is based on information given in the talk held
  63  *  by Henryk Ploetz and Karsten Nohl at 26c3
  64  */
  65 int CmdLegicDecode(const char *Cmd) {
  66
  67         int i = 0, k = 0, segmentNum = 0, segment_len = 0, segment_flag = 0;
  68         int crc = 0, wrp = 0, wrc = 0;
  69         uint8_t stamp_len = 0;
  70         uint8_t data_buf[1052]; // receiver buffer
  71         char token_type[5] = {0,0,0,0,0};
  72         int dcf = 0;
  73         int bIsSegmented = 0;
  74
  75         // download EML memory, where the "legic read" command puts the data.
  76         GetEMLFromBigBuf(data_buf, sizeof(data_buf), 0);
  77         if ( !WaitForResponseTimeout(CMD_ACK, NULL, 2000)){
  78                 PrintAndLog("Command execute timeout");
  79                 return 1;
  80         }
  81
  82         // Output CDF System area (9 bytes) plus remaining header area (12 bytes)
  83         crc = data_buf[4];
  84         uint32_t calc_crc =  CRC8Legic(data_buf, 4);
  85
  86         PrintAndLog("\nCDF: System Area");
  87         PrintAndLog("------------------------------------------------------");
  88         PrintAndLog("MCD: %02x, MSN: %02x %02x %02x, MCC: %02x %s",
  89                 data_buf[0],
  90                 data_buf[1],
  91                 data_buf[2],
  92                 data_buf[3],
  93                 data_buf[4],
  94                 (calc_crc == crc) ? "OK":"Fail"
  95         );
  96
  97
  98         token_type[0] = 0;
  99         dcf = ((int)data_buf[6] << 8) | (int)data_buf[5];
 100
 101         // New unwritten media?
 102         if(dcf == 0xFFFF) {
 103
 104                 PrintAndLog("DCF: %d (%02x %02x), Token Type=NM (New Media)",
 105                         dcf,
 106                         data_buf[5],
 107                         data_buf[6]
 108                 );
 109
 110         } else if(dcf > 60000) {                // Master token?
 111
 112                 int fl = 0;
 113
 114                 if(data_buf[6] == 0xec) {
 115                         strncpy(token_type, "XAM", sizeof(token_type));
 116                         fl = 1;
 117                         stamp_len = 0x0c - (data_buf[5] >> 4);
 118                 } else {
 119                         switch (data_buf[5] & 0x7f) {
 120                         case 0x00 ... 0x2f:
 121                                 strncpy(token_type, "IAM", sizeof(token_type));
 122                                 fl = (0x2f - (data_buf[5] & 0x7f)) + 1;
 123                                 break;
 124                         case 0x30 ... 0x6f:
 125                                 strncpy(token_type, "SAM", sizeof(token_type));
 126                                 fl = (0x6f - (data_buf[5] & 0x7f)) + 1;
 127                                 break;
 128                         case 0x70 ... 0x7f:
 129                                 strncpy(token_type, "GAM", sizeof(token_type));
 130                                 fl = (0x7f - (data_buf[5] & 0x7f)) + 1;
 131                                 break;
 132                         }
 133
 134                         stamp_len = 0xfc - data_buf[6];
 135                 }
 136
 137                 PrintAndLog("DCF: %d (%02x %02x), Token Type=%s (OLE=%01u), OL=%02u, FL=%02u",
 138                         dcf,
 139                         data_buf[5],
 140                         data_buf[6],
 141                         token_type,
 142                         (data_buf[5] & 0x80 )>> 7,
 143                         stamp_len,
 144                         fl
 145                 );
 146
 147         } else {        // Is IM(-S) type of card...
 148
 149                 if(data_buf[7] == 0x9F && data_buf[8] == 0xFF) {
 150                         bIsSegmented = 1;
 151                         strncpy(token_type, "IM-S", sizeof(token_type));
 152                 } else {
 153                         strncpy(token_type, "IM", sizeof(token_type));
 154                 }
 155
 156                 PrintAndLog("DCF: %d (%02x %02x), Token Type=%s (OLE=%01u)",
 157                         dcf,
 158                         data_buf[5],
 159                         data_buf[6],
 160                         token_type,
 161                         (data_buf[5]&0x80) >> 7
 162                 );
 163         }
 164
 165         // Makes no sence to show this on blank media...
 166         if(dcf != 0xFFFF) {
 167
 168                 if(bIsSegmented) {
 169                         PrintAndLog("WRP=%02u, WRC=%01u, RD=%01u, SSC=%02x",
 170                                 data_buf[7] & 0x0f,
 171                                 (data_buf[7] & 0x70) >> 4,
 172                                 (data_buf[7] & 0x80) >> 7,
 173                                 data_buf[8]
 174                         );
 175                 }
 176
 177                 // Header area is only available on IM-S cards, on master tokens this data is the master token data itself
 178                 if(bIsSegmented || dcf > 60000) {
 179                         if(dcf > 60000) {
 180                                 PrintAndLog("Master token data");
 181                                 PrintAndLog("%s", sprint_hex(data_buf+8, 14));
 182                         } else {
 183                                 PrintAndLog("Remaining Header Area");
 184                                 PrintAndLog("%s", sprint_hex(data_buf+9, 13));
 185                         }
 186                 }
 187         }
 188
 189         uint8_t segCrcBytes[8] = {0,0,0,0,0,0,0,0};
 190         uint32_t segCalcCRC = 0;
 191         uint32_t segCRC = 0;
 192
 193         // Data card?
 194         if(dcf <= 60000) {
 195
 196                 PrintAndLog("\nADF: User Area");
 197                 PrintAndLog("------------------------------------------------------");
 198
 199                 if(bIsSegmented) {
 200
 201                         // Data start point on segmented cards
 202                         i = 22;
 203
 204                         // decode segments
 205                         for (segmentNum=1; segmentNum < 128; segmentNum++ )
 206                         {
 207                                 segment_len = ((data_buf[i+1] ^ crc) & 0x0f) * 256 + (data_buf[i] ^ crc);
 208                                 segment_flag = ((data_buf[i+1] ^ crc) & 0xf0) >> 4;
 209                                 wrp = (data_buf[i+2] ^ crc);
 210                                 wrc = ((data_buf[i+3] ^ crc) & 0x70) >> 4;
 211
 212                                 bool hasWRC = (wrc > 0);
 213                                 bool hasWRP = (wrp > wrc);
 214                                 int wrp_len = (wrp - wrc);
 215                                 int remain_seg_payload_len = (segment_len - wrp - 5);
 216
 217                                 // validate segment-crc
 218                                 segCrcBytes[0]=data_buf[0];                     //uid0
 219                                 segCrcBytes[1]=data_buf[1];                     //uid1
 220                                 segCrcBytes[2]=data_buf[2];                     //uid2
 221                                 segCrcBytes[3]=data_buf[3];                     //uid3
 222                                 segCrcBytes[4]=(data_buf[i] ^ crc);   //hdr0
 223                                 segCrcBytes[5]=(data_buf[i+1] ^ crc); //hdr1
 224                                 segCrcBytes[6]=(data_buf[i+2] ^ crc); //hdr2
 225                                 segCrcBytes[7]=(data_buf[i+3] ^ crc); //hdr3
 226
 227                                 segCalcCRC = CRC8Legic(segCrcBytes, 8);
 228                                 segCRC = data_buf[i+4] ^ crc;
 229
 230                                 PrintAndLog("Segment %02u \nraw header | 0x%02X 0x%02X 0x%02X 0x%02X \nSegment len: %u,  Flag: 0x%X (valid:%01u, last:%01u), WRP: %02u, WRC: %02u, RD: %01u, CRC: 0x%02X (%s)",
 231                                         segmentNum,
 232                                         data_buf[i] ^ crc,
 233                                         data_buf[i+1] ^ crc,
 234                                         data_buf[i+2] ^ crc,
 235                                         data_buf[i+3] ^ crc,
 236                                         segment_len,
 237                                         segment_flag,
 238                                         (segment_flag & 0x4) >> 2,
 239                                         (segment_flag & 0x8) >> 3,
 240                                         wrp,
 241                                         wrc,
 242                                         ((data_buf[i+3]^crc) & 0x80) >> 7,
 243                                         segCRC,
 244                                         ( segCRC == segCalcCRC ) ? "OK" : "fail"
 245                                 );
 246
 247                                 i += 5;
 248
 249                                 if ( hasWRC ) {
 250                                         PrintAndLog("WRC protected area:   (I %d | K %d| WRC %d)", i, k, wrc);
 251                                         PrintAndLog("\nrow  | data");
 252                                         PrintAndLog("-----+------------------------------------------------");
 253
 254                                         for ( k=i; k < (i + wrc); ++k)
 255                                                 data_buf[k] ^= crc;
 256
 257                                         print_hex_break( data_buf+i, wrc, 16);
 258
 259                                         i += wrc;
 260                                 }
 261
 262                                 if ( hasWRP ) {
 263                                         PrintAndLog("Remaining write protected area:  (I %d | K %d | WRC %d | WRP %d  WRP_LEN %d)",i, k, wrc, wrp, wrp_len);
 264                                         PrintAndLog("\nrow  | data");
 265                                         PrintAndLog("-----+------------------------------------------------");
 266
 267                                         for (k=i; k < (i+wrp_len); ++k)
 268                                                 data_buf[k] ^= crc;
 269
 270                                         print_hex_break( data_buf+i, wrp_len, 16);
 271
 272                                         i += wrp_len;
 273
 274                                         // does this one work? (Answer: Only if KGH/BGH is used with BCD encoded card number! So maybe this will show just garbage...)
 275                                         if( wrp_len == 8 )
 276                                                 PrintAndLog("Card ID: %2X%02X%02X", data_buf[i-4]^crc, data_buf[i-3]^crc, data_buf[i-2]^crc);
 277                                 }
 278
 279                                 PrintAndLog("Remaining segment payload:  (I %d | K %d | Remain LEN %d)", i, k, remain_seg_payload_len);
 280                                 PrintAndLog("\nrow  | data");
 281                                 PrintAndLog("-----+------------------------------------------------");
 282
 283                                 for ( k=i; k < (i+remain_seg_payload_len); ++k)
 284                                         data_buf[k] ^= crc;
 285
 286                                 print_hex_break( data_buf+i, remain_seg_payload_len, 16);
 287
 288                                 i += remain_seg_payload_len;
 289
 290                                 PrintAndLog("-----+------------------------------------------------\n");
 291
 292                                 // end with last segment
 293                                 if (segment_flag & 0x8) return 0;
 294
 295                         } // end for loop
 296
 297                 } else {
 298
 299                         // Data start point on unsegmented cards
 300                         i = 8;
 301
 302                         wrp = data_buf[7] & 0x0F;
 303                         wrc = (data_buf[7] & 0x70) >> 4;
 304
 305                         bool hasWRC = (wrc > 0);
 306                         bool hasWRP = (wrp > wrc);
 307                         int wrp_len = (wrp - wrc);
 308                         int remain_seg_payload_len = (1024 - 22 - wrp); // Any chance to get physical card size here!?
 309
 310                         PrintAndLog("Unsegmented card - WRP: %02u, WRC: %02u, RD: %01u",
 311                                 wrp,
 312                                 wrc,
 313                                 (data_buf[7] & 0x80) >> 7
 314                         );
 315
 316                         if ( hasWRC ) {
 317                                 PrintAndLog("WRC protected area:   (I %d | WRC %d)", i, wrc);
 318                                 PrintAndLog("\nrow  | data");
 319                                 PrintAndLog("-----+------------------------------------------------");
 320                                 print_hex_break( data_buf+i, wrc, 16);
 321                                 i += wrc;
 322                         }
 323
 324                         if ( hasWRP ) {
 325                                 PrintAndLog("Remaining write protected area:  (I %d | WRC %d | WRP %d | WRP_LEN %d)", i, wrc, wrp, wrp_len);
 326                                 PrintAndLog("\nrow  | data");
 327                                 PrintAndLog("-----+------------------------------------------------");
 328                                 print_hex_break( data_buf + i, wrp_len, 16);
 329                                 i += wrp_len;
 330
 331                                 // does this one work? (Answer: Only if KGH/BGH is used with BCD encoded card number! So maybe this will show just garbage...)
 332                                 if( wrp_len == 8 )
 333                                         PrintAndLog("Card ID: %2X%02X%02X", data_buf[i-4], data_buf[i-3], data_buf[i-2]);
 334                         }
 335
 336                         PrintAndLog("Remaining segment payload:  (I %d | Remain LEN %d)", i, remain_seg_payload_len);
 337                         PrintAndLog("\nrow  | data");
 338                         PrintAndLog("-----+------------------------------------------------");
 339                         print_hex_break( data_buf + i, remain_seg_payload_len, 16);
 340                         i += remain_seg_payload_len;
 341
 342                         PrintAndLog("-----+------------------------------------------------\n");
 343                 }
 344         }
 345         return 0;
 346 }
 347
 348 int CmdLegicRFRead(const char *Cmd) {
 349
 350         // params:
 351         // offset in data
 352         // number of bytes.
 353         char cmdp = param_getchar(Cmd, 0);
 354         if ( cmdp == 'H' || cmdp == 'h' ) return usage_legic_read();
 355
 356         int byte_count = 0, offset = 0;
 357         sscanf(Cmd, "%i %i", &offset, &byte_count);
 358         if(byte_count == 0) byte_count = -1;
 359         if(byte_count + offset > 1024) byte_count = 1024 - offset;
 360
 361         UsbCommand c= {CMD_READER_LEGIC_RF, {offset, byte_count, 0}};
 362         clearCommandBuffer();
 363         SendCommand(&c);
 364         return 0;
 365 }
 366
 367
 368 int CmdLegicLoad(const char *Cmd) {
 369
 370 // iceman: potential bug, where all filepaths or filename which starts with H or h will print the helptext :)
 371         char cmdp = param_getchar(Cmd, 0);
 372         if ( cmdp == 'H' || cmdp == 'h' || cmdp == 0x00) return usage_legic_load();
 373
 374         char filename[FILE_PATH_SIZE] = {0x00};
 375         int len = strlen(Cmd);
 376
 377         if (len > FILE_PATH_SIZE) {
 378                 PrintAndLog("Filepath too long (was %s bytes), max allowed is %s ", len, FILE_PATH_SIZE);
 379                 return 0;
 380         }
 381         memcpy(filename, Cmd, len);
 382
 383     FILE *f = fopen(filename, "r");
 384     if(!f) {
 385         PrintAndLog("couldn't open '%s'", Cmd);
 386         return -1;
 387     }
 388
 389     char line[80];
 390         int offset = 0;
 391         uint8_t data[USB_CMD_DATA_SIZE] = {0x00};
 392         int index = 0;
 393         int totalbytes = 0;
 394     while ( fgets(line, sizeof(line), f) ) {
 395         int res = sscanf(line, "%x %x %x %x %x %x %x %x",
 396             (unsigned int *)&data[index],
 397                         (unsigned int *)&data[index + 1],
 398                         (unsigned int *)&data[index + 2],
 399                         (unsigned int *)&data[index + 3],
 400             (unsigned int *)&data[index + 4],
 401                         (unsigned int *)&data[index + 5],
 402                         (unsigned int *)&data[index + 6],
 403                         (unsigned int *)&data[index + 7]);
 404
 405         if(res != 8) {
 406           PrintAndLog("Error: could not read samples");
 407           fclose(f);
 408           return -1;
 409         }
 410                 index += res;
 411
 412                 if ( index == USB_CMD_DATA_SIZE ){
 413 //                      PrintAndLog("sent %d | %d | %d", index, offset, totalbytes);
 414                         UsbCommand c = { CMD_DOWNLOADED_SIM_SAMPLES_125K, {offset, 0, 0}};
 415                         memcpy(c.d.asBytes, data, sizeof(data));
 416                         clearCommandBuffer();
 417                         SendCommand(&c);
 418                         if ( !WaitForResponseTimeout(CMD_ACK, NULL, 1500)){
 419                                 PrintAndLog("Command execute timeout");
 420                                 fclose(f);
 421                                 return 1;
 422                         }
 423                         offset += index;
 424                         totalbytes += index;
 425                         index = 0;
 426                 }
 427     }
 428     fclose(f);
 429
 430         // left over bytes?
 431         if ( index != 0 ) {
 432                 UsbCommand c = { CMD_DOWNLOADED_SIM_SAMPLES_125K, {offset, 0, 0}};
 433                 memcpy(c.d.asBytes, data, 8);
 434                 clearCommandBuffer();
 435                 SendCommand(&c);
 436                 if ( !WaitForResponseTimeout(CMD_ACK, NULL, 1500)){
 437                                 PrintAndLog("Command execute timeout");
 438                                 return 1;
 439                 }
 440                 totalbytes += index;
 441         }
 442
 443     PrintAndLog("loaded %u samples", totalbytes);
 444     return 0;
 445 }
 446
 447 int CmdLegicSave(const char *Cmd) {
 448         int requested = 1024;
 449         int offset = 0;
 450         int delivered = 0;
 451         char filename[FILE_PATH_SIZE] = {0x00};
 452         uint8_t got[1024] = {0x00};
 453
 454         memset(filename, 0, FILE_PATH_SIZE);
 455
 456         sscanf(Cmd, " %s %i %i", filename, &requested, &offset);
 457
 458         /* If no length given save entire legic read buffer */
 459         /* round up to nearest 8 bytes so the saved data can be used with legicload */
 460         if (requested == 0)
 461                 requested = 1024;
 462
 463         if (requested % 8 != 0) {
 464                 int remainder = requested % 8;
 465                 requested = requested + 8 - remainder;
 466         }
 467
 468         if (offset + requested > sizeof(got)) {
 469                 PrintAndLog("Tried to read past end of buffer, <bytes> + <offset> > 1024");
 470                 return 0;
 471         }
 472
 473         GetFromBigBuf(got, requested, offset);
 474         if ( !WaitForResponseTimeout(CMD_ACK, NULL, 2000)){
 475                 PrintAndLog("Command execute timeout");
 476                 return 1;
 477         }
 478
 479         FILE *f = fopen(filename, "w");
 480         if(!f) {
 481                 PrintAndLog("couldn't open '%s'", Cmd+1);
 482                 return -1;
 483         }
 484
 485         for (int j = 0; j < requested; j += 8) {
 486                 fprintf(f, "%02x %02x %02x %02x %02x %02x %02x %02x\n",
 487                         got[j+0], got[j+1], got[j+2], got[j+3],
 488                         got[j+4], got[j+5],     got[j+6], got[j+7]
 489                 );
 490                 delivered += 8;
 491                 if (delivered >= requested) break;
 492         }
 493
 494         fclose(f);
 495         PrintAndLog("saved %u samples", delivered);
 496         return 0;
 497 }
 498
 499 //TODO: write a help text (iceman)
 500 int CmdLegicRfSim(const char *Cmd) {
 501         UsbCommand c = {CMD_SIMULATE_TAG_LEGIC_RF, {6,3,0}};
 502         sscanf(Cmd, " %"lli" %"lli" %"lli, &c.arg[0], &c.arg[1], &c.arg[2]);
 503         clearCommandBuffer();
 504         SendCommand(&c);
 505         return 0;
 506 }
 507
 508 //TODO: write a help text (iceman)
 509 int CmdLegicRfWrite(const char *Cmd) {
 510     UsbCommand c = {CMD_WRITER_LEGIC_RF, {0,0,0}};
 511     int res = sscanf(Cmd, " 0x%"llx" 0x%"llx, &c.arg[0], &c.arg[1]);
 512         if(res != 2) {
 513                 PrintAndLog("Please specify the offset and length as two hex strings");
 514         return -1;
 515     }
 516         clearCommandBuffer();
 517     SendCommand(&c);
 518     return 0;
 519 }
 520
 521 //TODO: write a help text (iceman)
 522 int CmdLegicRfRawWrite(const char *Cmd) {
 523         char answer;
 524     UsbCommand c = { CMD_RAW_WRITER_LEGIC_RF, {0,0,0} };
 525     int res = sscanf(Cmd, " 0x%"llx" 0x%"llx, &c.arg[0], &c.arg[1]);
 526         if(res != 2) {
 527                 PrintAndLog("Please specify the offset and value as two hex strings");
 528         return -1;
 529     }
 530
 531         if (c.arg[0] == 0x05 || c.arg[0] == 0x06) {
 532                 PrintAndLog("############# DANGER !! #############");
 533                 PrintAndLog("# changing the DCF is irreversible  #");
 534                 PrintAndLog("#####################################");
 535                 PrintAndLog("do youe really want to continue? y(es) n(o)");
 536                 if (scanf(" %c", &answer) > 0 && (answer == 'y' || answer == 'Y')) {
 537                         SendCommand(&c);
 538                         return 0;
 539                 }
 540                 return -1;
 541         }
 542
 543         clearCommandBuffer();
 544     SendCommand(&c);
 545         return 0;
 546 }
 547
 548 //TODO: write a help text (iceman)
 549 int CmdLegicRfFill(const char *Cmd) {
 550     UsbCommand cmd = {CMD_WRITER_LEGIC_RF, {0,0,0} };
 551     int res = sscanf(Cmd, " 0x%"llx" 0x%"llx" 0x%"llx, &cmd.arg[0], &cmd.arg[1], &cmd.arg[2]);
 552     if(res != 3) {
 553         PrintAndLog("Please specify the offset, length and value as two hex strings");
 554         return -1;
 555     }
 556
 557     int i;
 558     UsbCommand c = {CMD_DOWNLOADED_SIM_SAMPLES_125K, {0, 0, 0}};
 559         memset(c.d.asBytes, cmd.arg[2], 48);
 560
 561         for(i = 0; i < 22; i++) {
 562                 c.arg[0] = i*48;
 563
 564                 clearCommandBuffer();
 565                 SendCommand(&c);
 566                 WaitForResponse(CMD_ACK, NULL);
 567         }
 568         clearCommandBuffer();
 569     SendCommand(&cmd);
 570     return 0;
 571  }
 572
 573 int CmdLegicCalcCrc8(const char *Cmd){
 574
 575         uint8_t *data = NULL;
 576         uint8_t cmdp = 0, uidcrc = 0, type=0;
 577         bool errors = false;
 578         int len = 0;
 579         int bg, en;
 580
 581         while(param_getchar(Cmd, cmdp) != 0x00) {
 582                 switch(param_getchar(Cmd, cmdp)) {
 583                 case 'b':
 584                 case 'B':
 585                         // peek at length of the input string so we can
 586                         // figure out how many elements to malloc in "data"
 587                         bg=en=0;
 588                         if (param_getptr(Cmd, &bg, &en, cmdp+1)) {
 589                                 errors = true;
 590                                 break;
 591                         }
 592                         len = (en - bg + 1);
 593
 594                         // check that user entered even number of characters
 595                         // for hex data string
 596                         if (len & 1) {
 597                                 errors = true;
 598                                 break;
 599                         }
 600
 601                         // it's possible for user to accidentally enter "b" parameter
 602                         // more than once - we have to clean previous malloc
 603                         if (data) free(data);
 604                         data = malloc(len >> 1);
 605                         if ( data == NULL ) {
 606                                 PrintAndLog("Can't allocate memory. exiting");
 607                                 errors = true;
 608                                 break;
 609                         }
 610
 611                         if (param_gethex(Cmd, cmdp+1, data, len)) {
 612                                 errors = true;
 613                                 break;
 614                         }
 615
 616                         len >>= 1;
 617                         cmdp += 2;
 618                         break;
 619                 case 'u':
 620                 case 'U':
 621                         uidcrc = param_get8ex(Cmd, cmdp+1, 0, 16);
 622                         cmdp += 2;
 623                         break;
 624                 case 'c':
 625                 case 'C':
 626                         type = param_get8ex(Cmd, cmdp+1, 0, 10);
 627                         cmdp += 2;
 628                         break;
 629                 case 'h':
 630                 case 'H':
 631                         errors = true;
 632                         break;
 633                 default:
 634                         PrintAndLog("Unknown parameter '%c'", param_getchar(Cmd, cmdp));
 635                         errors = true;
 636                         break;
 637                 }
 638                 if (errors) break;
 639         }
 640         //Validations
 641         if (errors){
 642                 if (data) free(data);
 643                 return usage_legic_calccrc8();
 644         }
 645
 646         switch (type){
 647                 case 16:
 648                         PrintAndLog("LEGIC CRC16: %X", CRC16Legic(data, len, uidcrc));
 649                         break;
 650                 default:
 651                         PrintAndLog("LEGIC CRC8: %X",  CRC8Legic(data, len) );
 652                         break;
 653         }
 654
 655         if (data) free(data);
 656         return 0;
 657 }
 658
 659 static command_t CommandTable[] =  {
 660         {"help",        CmdHelp,        1, "This help"},
 661         {"decode",      CmdLegicDecode, 0, "Display deobfuscated and decoded LEGIC RF tag data (use after hf legic reader)"},
 662         {"read",        CmdLegicRFRead, 0, "[offset][length] -- read bytes from a LEGIC card"},
 663         {"save",        CmdLegicSave,   0, "<filename> [<length>] -- Store samples"},
 664         {"load",        CmdLegicLoad,   0, "<filename> -- Restore samples"},
 665         {"sim",         CmdLegicRfSim,  0, "[phase drift [frame drift [req/resp drift]]] Start tag simulator (use after load or read)"},
 666         {"write",       CmdLegicRfWrite,0, "<offset> <length> -- Write sample buffer (user after load or read)"},
 667         {"writeRaw",CmdLegicRfRawWrite, 0, "<address> <value> -- Write direct to address"},
 668         {"fill",        CmdLegicRfFill, 0, "<offset> <length> <value> -- Fill/Write tag with constant value"},
 669         {"crc8",        CmdLegicCalcCrc8, 1, "Calculate Legic CRC8 over given hexbytes"},
 670         {NULL, NULL, 0, NULL}
 671 };
 672
 673 int CmdHFLegic(const char *Cmd) {
 674         clearCommandBuffer();
 675         CmdsParse(CommandTable, Cmd);
 676         return 0;
 677 }
 678
 679 int CmdHelp(const char *Cmd) {
 680         CmdsHelp(CommandTable);
 681         return 0;
 682 }