client/src/cmdcrc.c

   1 //-----------------------------------------------------------------------------
   2 // Borrowed initially from https://reveng.sourceforge.io/
   3 // Copyright (C) Greg Cook 2019
   4 // Copyright (C) Proxmark3 contributors. See AUTHORS.md for details.
   5 //
   6 // This program is free software: you can redistribute it and/or modify
   7 // it under the terms of the GNU General Public License as published by
   8 // the Free Software Foundation, either version 3 of the License, or
   9 // (at your option) any later version.
  10 //
  11 // This program is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15 //
  16 // See LICENSE.txt for the text of the license.
  17 //-----------------------------------------------------------------------------
  18 // CRC Calculations
  19 //-----------------------------------------------------------------------------
  20 #include "cmdcrc.h"
  21
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <stdlib.h>
  25 #include <ctype.h>
  26
  27 #ifdef _WIN32
  28 #  include <io.h>
  29 #  include <fcntl.h>
  30 #  ifndef STDIN_FILENO
  31 #    define STDIN_FILENO 0
  32 #  endif /* STDIN_FILENO */
  33 #endif /* _WIN32 */
  34
  35 #include "reveng.h"
  36 #include "ui.h"
  37 #include "util.h"
  38 #include "pm3_cmd.h"
  39
  40 #define MAX_ARGS 20
  41
  42 static int split(char *str, char *arr[MAX_ARGS]) {
  43     int beginIndex = 0;
  44     int wordCnt = 0;
  45
  46     while (1) {
  47         while (isspace(str[beginIndex])) {
  48             ++beginIndex;
  49         }
  50         if (str[beginIndex] == '\0') {
  51             break;
  52         }
  53         int endIndex = beginIndex;
  54         while (str[endIndex] && !isspace(str[endIndex])) {
  55             ++endIndex;
  56         }
  57         int len = endIndex - beginIndex;
  58         char *tmp = calloc(len + 1, sizeof(char));
  59         memcpy(tmp, &str[beginIndex], len);
  60         arr[wordCnt++] = tmp;
  61         beginIndex = endIndex;
  62         if (wordCnt == MAX_ARGS)
  63             break;
  64     }
  65     return wordCnt;
  66 }
  67
  68 //returns array of model names and the count of models returning
  69 //  as well as a width array for the width of each model
  70 int GetModels(char *Models[], int *count, uint8_t *width) {
  71     /* default values */
  72     static model_t model = MZERO;
  73
  74     poly_t apoly, crc, qpoly = PZERO, *apolys = NULL, *pptr = NULL, *qptr = NULL;
  75     model_t pset = model;
  76
  77     /* stdin must be binary */
  78 #ifdef _WIN32
  79     _setmode(STDIN_FILENO, _O_BINARY);
  80 #endif /* _WIN32 */
  81
  82     SETBMP();
  83
  84     if (width[0] == 0) { //reveng -D
  85         *count = mcount();
  86         if (!*count) {
  87             PrintAndLogEx(WARNING, "no preset models available");
  88             return 0;
  89         }
  90         for (int mode = 0; mode < *count; ++mode) {
  91             mbynum(&model, mode);
  92             mcanon(&model);
  93             size_t size = (model.name && *model.name) ? strlen(model.name) : 7;
  94             char *tmp = calloc(size + 1, sizeof(char));
  95             if (tmp == NULL) {
  96                 PrintAndLogEx(WARNING, "out of memory?");
  97                 return 0;
  98             }
  99             if (model.name != NULL) {
 100                 memcpy(tmp, model.name, size);
 101                 Models[mode] = tmp;
 102                 width[mode] = plen(model.spoly);
 103             } else {
 104                 free(tmp);
 105             }
 106         }
 107         mfree(&model);
 108     } else { //reveng -s
 109
 110         int ibperhx = 8;//, obperhx = 8;
 111         int rflags = 0, uflags = 0; /* search and UI flags */
 112         if (~model.flags & P_MULXN) {
 113             PrintAndLogEx(WARNING, "cannot search for non-Williams compliant models");
 114             return 0;
 115         }
 116         praloc(&model.spoly, (unsigned long)width[0]);
 117         praloc(&model.init, (unsigned long)width[0]);
 118         praloc(&model.xorout, (unsigned long)width[0]);
 119
 120         if (!plen(model.spoly))
 121             palloc(&model.spoly, (unsigned long)width[0]);
 122         else
 123             width[0] = (uint8_t)plen(model.spoly);
 124
 125         /* special case if qpoly is zero, search to end of range */
 126         if (!ptst(qpoly))
 127             rflags &= ~R_HAVEQ;
 128
 129         int pass;
 130
 131         /* if endianness not specified, try
 132          * little-endian then big-endian.
 133          * NB: crossed-endian algorithms will not be
 134          * searched.
 135          */
 136         /* scan against preset models */
 137         if (~uflags & C_NOPCK) {
 138             pass = 0;
 139             int Cnt = 0;
 140             do {
 141                 int psets = mcount();
 142
 143                 while (psets) {
 144                     mbynum(&pset, --psets);
 145
 146                     /* skip if different width, or refin or refout don't match */
 147                     if (plen(pset.spoly) != width[0] || (model.flags ^ pset.flags) & (P_REFIN | P_REFOUT))
 148                         continue;
 149                     /* skip if the preset doesn't match specified parameters */
 150                     if (rflags & R_HAVEP && pcmp(&model.spoly, &pset.spoly))
 151                         continue;
 152                     if (rflags & R_HAVEI && psncmp(&model.init, &pset.init))
 153                         continue;
 154                     if (rflags & R_HAVEX && psncmp(&model.xorout, &pset.xorout))
 155                         continue;
 156
 157                     //for additional args (not used yet, maybe future?)
 158                     apoly = pclone(pset.xorout);
 159
 160                     if (pset.flags & P_REFOUT)
 161                         prev(&apoly);
 162
 163
 164                     for (qptr = apolys; qptr < pptr; ++qptr) {
 165                         crc = pcrc(*qptr, pset.spoly, pset.init, apoly, 0);
 166                         if (ptst(crc)) {
 167                             pfree(&crc);
 168                             break;
 169                         }
 170                         pfree(&crc);
 171                     }
 172                     pfree(&apoly);
 173
 174                     if (qptr == pptr) {
 175
 176                         /* the selected model solved all arguments */
 177                         mcanon(&pset);
 178
 179                         size_t size = (pset.name && *pset.name) ? strlen(pset.name) : 7;
 180                         //PrintAndLogEx(NORMAL, "Size: %d, %s, count: %d",size,pset.name, Cnt);
 181                         char *tmp = calloc(size + 1, sizeof(char));
 182                         if (tmp == NULL) {
 183                             PrintAndLogEx(WARNING, "out of memory?");
 184                             return 0;
 185                         }
 186                         width[Cnt] = width[0];
 187                         memcpy(tmp, pset.name, size);
 188                         Models[Cnt++] = tmp;
 189                         *count = Cnt;
 190                         uflags |= C_RESULT;
 191                     }
 192                 }
 193                 mfree(&pset);
 194
 195                 /* toggle refIn/refOut and reflect arguments */
 196                 if (~rflags & R_HAVERI) {
 197                     model.flags ^= P_REFIN | P_REFOUT;
 198                     for (qptr = apolys; qptr < pptr; ++qptr) {
 199                         prevch(qptr, ibperhx);
 200                     }
 201                 }
 202             } while (~rflags & R_HAVERI && ++pass < 2);
 203         }
 204         //got everything now free the memory...
 205
 206         if (uflags & C_RESULT) {
 207             for (qptr = apolys; qptr < pptr; ++qptr) {
 208                 pfree(qptr);
 209             }
 210         }
 211         if (uflags & C_NOBFS && ~rflags & R_HAVEP) {
 212             PrintAndLogEx(WARNING, "no models found");
 213             return 0;
 214         }
 215
 216         if (!(model.flags & P_REFIN) != !(model.flags & P_REFOUT)) {
 217             PrintAndLogEx(WARNING, "cannot search for crossed-endian models");
 218             return 0;
 219         }
 220         pass = 0;
 221         int args = 0;
 222         do {
 223             model_t *candmods = reveng(&model, qpoly, rflags, args, apolys);
 224             model_t *mptr = candmods;
 225             if (mptr && plen(mptr->spoly)) {
 226                 uflags |= C_RESULT;
 227             }
 228             while (mptr && plen(mptr->spoly)) {
 229                 mfree(mptr++);
 230             }
 231             free(candmods);
 232             if (~rflags & R_HAVERI) {
 233                 model.flags ^= P_REFIN | P_REFOUT;
 234                 for (qptr = apolys; qptr < pptr; ++qptr) {
 235                     prevch(qptr, ibperhx);
 236                 }
 237             }
 238         } while (~rflags & R_HAVERI && ++pass < 2);
 239
 240         for (qptr = apolys; qptr < pptr; ++qptr) {
 241             pfree(qptr);
 242         }
 243         free(apolys);
 244         mfree(&model);
 245
 246         if (~uflags & C_RESULT) {
 247             PrintAndLogEx(WARNING, "no models found");
 248             return 0;
 249         }
 250     }
 251     return 1;
 252 }
 253
 254 //-c || -v
 255 //inModel = valid model name string - CRC-8
 256 //inHexStr = input hex string to calculate crc on
 257 //reverse = reverse calc option if true
 258 //endian = {0 = calc default endian input and output, b = big endian input and output, B = big endian output, r = right justified
 259 //          l = little endian input and output, L = little endian output only, t = left justified}
 260 //result = calculated crc hex string
 261 int RunModel(char *inModel, char *inHexStr, bool reverse, char endian, char *result) {
 262     /* default values */
 263     static model_t model = MZERO;
 264
 265     int ibperhx = 8, obperhx = 8;
 266 //    int rflags = 0; // search flags
 267     poly_t apoly, crc;
 268
 269     char *string;
 270
 271     // stdin must be binary
 272 #ifdef _WIN32
 273     _setmode(STDIN_FILENO, _O_BINARY);
 274 #endif /* _WIN32 */
 275
 276     SETBMP();
 277     //set model
 278     int c = mbynam(&model, inModel);
 279     if (!c) {
 280         PrintAndLogEx(ERR, "error: preset model '%s' not found.  Use reveng -D to list presets. [%d]", inModel, c);
 281         return 0;
 282     }
 283     if (c < 0) {
 284         PrintAndLogEx(WARNING, "no preset models available");
 285         return 0;
 286     }
 287 //    rflags |= R_HAVEP | R_HAVEI | R_HAVERI | R_HAVERO | R_HAVEX;
 288
 289     //set flags
 290     switch (endian) {
 291         case 'b': /* b  big-endian (RefIn = false, RefOut = false ) */
 292             model.flags &= ~P_REFIN;
 293         //rflags |= R_HAVERI;
 294         /* fall through: */
 295         case 'B': /* B  big-endian output (RefOut = false) */
 296             model.flags &= ~P_REFOUT;
 297             //rflags |= R_HAVERO;
 298             mnovel(&model);
 299         /* fall through: */
 300         case 'r': /* r  right-justified */
 301             model.flags |= P_RTJUST;
 302             break;
 303         case 'l': /* l  little-endian input and output */
 304             model.flags |= P_REFIN;
 305         //rflags |= R_HAVERI;
 306         /* fall through: */
 307         case 'L': /* L  little-endian output */
 308             model.flags |= P_REFOUT;
 309             //rflags |= R_HAVERO;
 310             mnovel(&model);
 311         /* fall through: */
 312         case 't': /* t  left-justified */
 313             model.flags &= ~P_RTJUST;
 314             break;
 315     }
 316     /* canonicalise the model, so the one we dump is the one we
 317      * calculate with (not with -s, spoly may be blank which will
 318      * normalise to zero and clear init and xorout.)
 319      */
 320     mcanon(&model);
 321
 322
 323     if (reverse) {
 324         // v  calculate reversed CRC
 325         /* Distinct from the -V switch as this causes
 326          * the arguments and output to be reversed as well.
 327          */
 328         // reciprocate Poly
 329         prcp(&model.spoly);
 330
 331         /* mrev() does:
 332          *   if(refout) prev(init); else prev(xorout);
 333          * but here the entire argument polynomial is
 334          * reflected, not just the characters, so RefIn
 335          * and RefOut are not inverted as with -V.
 336          * Consequently Init is the mirror image of the
 337          * one resulting from -V, and so we have:
 338          */
 339         if (~model.flags & P_REFOUT) {
 340             prev(&model.init);
 341             prev(&model.xorout);
 342         }
 343
 344         // swap init and xorout
 345         apoly = model.init;
 346         model.init = model.xorout;
 347         model.xorout = apoly;
 348     }
 349     // c  calculate CRC
 350
 351     /* in the Williams model, xorout is applied after the refout stage.
 352      * as refout is part of ptostr(), we reverse xorout here.
 353      */
 354     if (model.flags & P_REFOUT)
 355         prev(&model.xorout);
 356
 357     apoly = strtop(inHexStr, model.flags, ibperhx);
 358
 359     if (reverse)
 360         prev(&apoly);
 361
 362     crc = pcrc(apoly, model.spoly, model.init, model.xorout, model.flags);
 363
 364     if (reverse)
 365         prev(&crc);
 366
 367     string = ptostr(crc, model.flags, obperhx);
 368     for (int i = 0; i < 50; i++) {
 369         result[i] = string[i];
 370         if (result[i] == 0) break;
 371     }
 372     free(string);
 373     pfree(&crc);
 374     pfree(&apoly);
 375     return 1;
 376 }
 377 /*
 378 //test call to RunModel
 379 static int CmdrevengTestC(const char *Cmd) {
 380     int cmdp = 0;
 381     char inModel[30] = {0x00};
 382     char inHexStr[30] = {0x00};
 383     char result[30];
 384     int dataLen;
 385     char endian = 0;
 386     dataLen = param_getstr(Cmd, cmdp++, inModel, sizeof(inModel));
 387     if (dataLen < 4) return 0;
 388     dataLen = param_getstr(Cmd, cmdp++, inHexStr, sizeof(inHexStr));
 389     if (dataLen < 4) return 0;
 390     bool reverse = (param_get8(Cmd, cmdp++)) ? true : false;
 391     endian = param_getchar(Cmd, cmdp++);
 392
 393     //PrintAndLogEx(NORMAL, "mod: %s, hex: %s, rev %d", inModel, inHexStr, reverse);
 394     int ans = RunModel(inModel, inHexStr, reverse, endian, result);
 395     if (!ans) return 0;
 396
 397     PrintAndLogEx(SUCCESS, "result: %s", result);
 398     return 1;
 399 }
 400 */
 401 //returns a calloced string (needs to be freed)
 402 static char *SwapEndianStr(const char *inStr, const size_t len, const uint8_t blockSize) {
 403     char *tmp = calloc(len + 1, sizeof(char));
 404     for (uint8_t block = 0; block < (uint8_t)(len / blockSize); block++) {
 405         for (size_t i = 0; i < blockSize; i += 2) {
 406             tmp[i + (blockSize * block)] = inStr[(blockSize - 1 - i - 1) + (blockSize * block)];
 407             tmp[i + (blockSize * block) + 1] = inStr[(blockSize - 1 - i) + (blockSize * block)];
 408         }
 409     }
 410     return tmp;
 411 }
 412
 413 // takes hex string in and searches for a matching result (hex string must include checksum)
 414 static int CmdrevengSearch(const char *Cmd) {
 415
 416 #define NMODELS 106
 417
 418     char inHexStr[256] = {0x00};
 419     int dataLen = param_getstr(Cmd, 0, inHexStr, sizeof(inHexStr));
 420     if (dataLen < 4) return 0;
 421
 422     // these two arrays, must match preset size.
 423     char *Models[NMODELS];
 424     uint8_t width[NMODELS] = {0};
 425     int count = 0;
 426
 427     char result[50 + 1] = {0};
 428     char revResult[50 + 1] = {0};
 429     int ans = GetModels(Models, &count, width);
 430     bool found = false;
 431     if (!ans) {
 432         for (int i = 0; i < count; i++) {
 433             free(Models[i]);
 434         }
 435         return 0;
 436     }
 437
 438     str_lower(inHexStr);
 439
 440     // try each model and get result
 441     for (int i = 0; i < count; i++) {
 442         /*if (found) {
 443             free(Models[i]);
 444             continue;
 445         }*/
 446         // round up to # of characters in this model's crc
 447         uint8_t crcChars = ((width[i] + 7) / 8) * 2;
 448         // can't test a model that has more crc digits than our data
 449         if (crcChars >= dataLen) {
 450             free(Models[i]);
 451             continue;
 452         }
 453
 454         PrintAndLogEx(DEBUG
 455                       , "DEBUG: dataLen %d, crcChars %u,  width[i] %u"
 456                       , dataLen
 457                       , crcChars
 458                       , width[i]
 459                      );
 460
 461         if (crcChars == 0) {
 462             free(Models[i]);
 463             continue;
 464         }
 465
 466         memset(result, 0, sizeof(result));
 467         char *inCRC = calloc(crcChars + 1, sizeof(char));
 468         if (inCRC == NULL) {
 469             return 0;
 470         }
 471
 472         memcpy(inCRC, inHexStr + (dataLen - crcChars), crcChars);
 473
 474         char *outHex = calloc(dataLen - crcChars + 1, sizeof(char));
 475         if (outHex == NULL) {
 476             free(inCRC);
 477             return 0;
 478         }
 479
 480         memcpy(outHex, inHexStr, dataLen - crcChars);
 481
 482         ans = RunModel(Models[i], outHex, false, 0, result);
 483         if (ans) {
 484
 485             str_lower(result);
 486
 487             // test for match
 488             if (memcmp(result, inCRC, crcChars) == 0) {
 489                 PrintAndLogEx(SUCCESS, "model... " _YELLOW_("%s"), Models[i]);
 490                 PrintAndLogEx(SUCCESS, "value... %s\n", result);
 491                 //optional - stop searching if found...
 492                 found = true;
 493             } else {
 494                 if (crcChars > 2) {
 495                     char *swapEndian = SwapEndianStr(result, crcChars, crcChars);
 496                     if (memcmp(swapEndian, inCRC, crcChars) == 0) {
 497                         PrintAndLogEx(SUCCESS, "model... " _YELLOW_("%s"), Models[i]);
 498                         PrintAndLogEx(SUCCESS, "value endian swapped... %s\n", swapEndian);
 499                         // optional - stop searching if found...
 500                         found = true;
 501                     }
 502                     free(swapEndian);
 503                 }
 504             }
 505         }
 506         ans = RunModel(Models[i], outHex, true, 0, revResult);
 507         if (ans) {
 508             str_lower(revResult);
 509
 510             // test for match
 511             if (memcmp(revResult, inCRC, crcChars) == 0) {
 512                 PrintAndLogEx(SUCCESS, "model reversed... " _YELLOW_("%s"), Models[i]);
 513                 PrintAndLogEx(SUCCESS, "value... %s\n", revResult);
 514                 // optional - stop searching if found...
 515                 found = true;
 516             } else {
 517                 if (crcChars > 2) {
 518                     char *swapEndian = SwapEndianStr(revResult, crcChars, crcChars);
 519                     if (memcmp(swapEndian, inCRC, crcChars) == 0) {
 520                         PrintAndLogEx(SUCCESS, "model reversed... " _YELLOW_("%s"), Models[i]);
 521                         PrintAndLogEx(SUCCESS, "value endian swapped... %s\n", swapEndian);
 522                         // optional - stop searching if found...
 523                         found = true;
 524                     }
 525                     free(swapEndian);
 526                 }
 527             }
 528         }
 529         free(inCRC);
 530         free(outHex);
 531         free(Models[i]);
 532     }
 533
 534     if (found == false) {
 535         PrintAndLogEx(FAILED, "\nno matches found\n");
 536     }
 537     return PM3_SUCCESS;
 538 }
 539
 540 int CmdCrc(const char *Cmd) {
 541     char c[100 + 7];
 542     snprintf(c, sizeof(c), "reveng ");
 543     snprintf(c + strlen(c), sizeof(c) - strlen(c), Cmd, strlen(Cmd));
 544
 545     char *argv[MAX_ARGS];
 546     int argc = split(c, argv);
 547
 548     if (argc == 3 && memcmp(argv[1], "-g", 2) == 0) {
 549         CmdrevengSearch(argv[2]);
 550     } else {
 551         reveng_main(argc, argv);
 552     }
 553
 554     for (int i = 0; i < argc; ++i) {
 555         free(argv[i]);
 556     }
 557     return PM3_SUCCESS;
 558 }
 559