git.zerfleddert.de Git - proxmark3-svn/blob - armsrc/pcf7931.c

   1 #include "proxmark3.h"
   2 #include "apps.h"
   3 #include "lfsampling.h"
   4 #include "pcf7931.h"
   5 #include "util.h"
   6 #include "string.h"
   7
   8 #define T0_PCF 8 //period for the pcf7931 in us
   9 #define ALLOC 16
  10
  11 size_t DemodPCF7931(uint8_t **outBlocks) {
  12         uint8_t bits[256] = {0x00};
  13         uint8_t blocks[8][16];
  14         uint8_t *dest = BigBuf_get_addr();
  15
  16         int GraphTraceLen = BigBuf_max_traceLen();
  17         if (GraphTraceLen > 18000)
  18                 GraphTraceLen = 18000;
  19
  20         int i, j, lastval, bitidx, half_switch;
  21         int clock = 64;
  22         int tolerance = clock / 8;
  23         int pmc, block_done;
  24         int lc, warnings = 0;
  25         size_t num_blocks = 0;
  26         int lmin=128, lmax=128;
  27         uint8_t dir;
  28         //clear read buffer
  29         BigBuf_Clear_keep_EM();
  30
  31         LFSetupFPGAForADC(95, true);
  32         DoAcquisition_default(0, true);
  33
  34         lmin = 64;
  35         lmax = 192;
  36
  37         i = 2;
  38
  39         /* Find first local max/min */
  40         if(dest[1] > dest[0]) {
  41                 while(i < GraphTraceLen) {
  42                         if( !(dest[i] > dest[i-1]) && dest[i] > lmax)
  43                                 break;
  44                         i++;
  45                 }
  46                 dir = 0;
  47         } else {
  48                 while(i < GraphTraceLen) {
  49                         if( !(dest[i] < dest[i-1]) && dest[i] < lmin)
  50                                 break;
  51                         i++;
  52                 }
  53                 dir = 1;
  54         }
  55
  56         lastval = i++;
  57         half_switch = 0;
  58         pmc = 0;
  59         block_done = 0;
  60
  61         for (bitidx = 0; i < GraphTraceLen; i++) {
  62                 if ((dest[i-1] > dest[i] && dir == 1 && dest[i] > lmax) || (dest[i-1] < dest[i] && dir == 0 && dest[i] < lmin)) {
  63                         lc = i - lastval;
  64                         lastval = i;
  65
  66                         // Switch depending on lc length:
  67                         // Tolerance is 1/8 of clock rate (arbitrary)
  68                         if (ABS(lc-clock/4) < tolerance) {
  69                                 // 16T0
  70                                 if((i - pmc) == lc) { /* 16T0 was previous one */
  71                                         /* It's a PMC ! */
  72                                         i += (128+127+16+32+33+16)-1;
  73                                         lastval = i;
  74                                         pmc = 0;
  75                                         block_done = 1;
  76                                 } else {
  77                                         pmc = i;
  78                                 }
  79                         } else if (ABS(lc-clock/2) < tolerance) {
  80                                 // 32TO
  81                                 if((i - pmc) == lc) { /* 16T0 was previous one */
  82                                         /* It's a PMC ! */
  83                                         i += (128+127+16+32+33)-1;
  84                                         lastval = i;
  85                                         pmc = 0;
  86                                         block_done = 1;
  87                                 } else if(half_switch == 1) {
  88                                         bits[bitidx++] = 0;
  89                                         half_switch = 0;
  90                                 }
  91                                 else
  92                                         half_switch++;
  93                         } else if (ABS(lc-clock) < tolerance) {
  94                                 // 64TO
  95                                 bits[bitidx++] = 1;
  96                         } else {
  97                                 // Error
  98                                 if (++warnings > 10) {
  99                                         Dbprintf("Error: too many detection errors, aborting.");
 100                                         return 0;
 101                                 }
 102                         }
 103
 104                         if(block_done == 1) {
 105                                 if(bitidx == 128) {
 106                                         for(j = 0; j < 16; ++j) {
 107                                                 blocks[num_blocks][j] =
 108                                                         128 * bits[j*8 + 7]+
 109                                                         64 * bits[j*8 + 6] +
 110                                                         32 * bits[j*8 + 5] +
 111                                                         16 * bits[j*8 + 4] +
 112                                                         8 * bits[j*8 + 3] +
 113                                                         4 * bits[j*8 + 2] +
 114                                                         2 * bits[j*8 + 1] +
 115                                                         bits[j*8]
 116                                                 ;
 117                                         }
 118                                         num_blocks++;
 119                                 }
 120                                 bitidx = 0;
 121                                 block_done = 0;
 122                                 half_switch = 0;
 123                         }
 124                         if(i < GraphTraceLen)
 125                                 dir = (dest[i-1] > dest[i]) ? 0 : 1;
 126                 }
 127                 if(bitidx==255)
 128                         bitidx=0;
 129                 warnings = 0;
 130                 if(num_blocks == 4) break;
 131         }
 132         memcpy(outBlocks, blocks, 16 * num_blocks);
 133         return num_blocks;
 134 }
 135
 136 bool IsBlock0PCF7931(uint8_t *block) {
 137         // assuming all RFU bits are set to 0
 138         // if PAC is enabled password is set to 0
 139         if (block[7] == 0x01)
 140         {
 141                 if (!memcmp(block, "\x00\x00\x00\x00\x00\x00\x00", 7) && !memcmp(block+9, "\x00\x00\x00\x00\x00\x00\x00", 7))
 142                         return true;
 143         }
 144         else if (block[7] == 0x00)
 145         {
 146                 if (!memcmp(block+9, "\x00\x00\x00\x00\x00\x00\x00", 7))
 147                         return true;
 148         }
 149         return false;
 150 }
 151
 152 bool IsBlock1PCF7931(uint8_t *block) {
 153         // assuming all RFU bits are set to 0
 154         if (block[10] == 0 && block[11] == 0 && block[12] == 0 && block[13] == 0)
 155                 if((block[14] & 0x7f) <= 9 && block[15] <= 9)
 156                         return true;
 157
 158         return false;
 159 }
 160
 161 void ReadPCF7931() {
 162         int found_blocks = 0; // successfully read blocks
 163         int max_blocks = 8;     // readable blocks
 164         uint8_t memory_blocks[8][17]; // PCF content
 165
 166         uint8_t single_blocks[8][17]; // PFC blocks with unknown position
 167         int single_blocks_cnt = 0;
 168
 169         size_t n = 0; // transmitted blocks
 170         uint8_t tmp_blocks[4][16]; // temporary read buffer
 171
 172         uint8_t found_0_1 = 0; // flag: blocks 0 and 1 were found
 173         int errors = 0; // error counter
 174         int tries = 0; // tries counter
 175
 176         memset(memory_blocks, 0, 8*17*sizeof(uint8_t));
 177         memset(single_blocks, 0, 8*17*sizeof(uint8_t));
 178
 179         int i = 0, j = 0;
 180
 181         do {
 182                 i = 0;
 183
 184                 memset(tmp_blocks, 0, 4*16*sizeof(uint8_t));
 185                 n = DemodPCF7931((uint8_t**)tmp_blocks);
 186                 if(!n)
 187                         ++errors;
 188
 189                 // exit if no block is received
 190                 if (errors >= 10 && found_blocks == 0 && single_blocks_cnt == 0) {
 191                         Dbprintf("Error, no tag or bad tag");
 192                         return;
 193                 }
 194                 // exit if too many errors during reading
 195                 if (tries > 50 && (2*errors > tries)) {
 196                         Dbprintf("Error reading the tag");
 197                         Dbprintf("Here is the partial content");
 198                         goto end;
 199                 }
 200
 201                 // our logic breaks if we don't get at least two blocks
 202                 if (n < 2) {
 203                         if (n == 0 || !memcmp(tmp_blocks[0], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16))
 204                                 continue;
 205
 206                         if (single_blocks_cnt < max_blocks) {
 207                                 for (i = 0; i < single_blocks_cnt; ++i) {
 208                                         if (!memcmp(single_blocks[i], tmp_blocks[0], 16)) {
 209                                                 j = 1;
 210                                                 break;
 211                                         }
 212                                 }
 213                                 if (j != 1) {
 214                                         memcpy(single_blocks[single_blocks_cnt], tmp_blocks[0], 16);
 215                                         single_blocks_cnt++;
 216                                 }
 217                                 j = 0;
 218                         }
 219                         ++tries;
 220                         continue;
 221                 }
 222
 223                 Dbprintf("(dbg) got %d blocks (%d/%d found) (%d tries, %d errors)", n, found_blocks, (max_blocks == 0 ? found_blocks : max_blocks), tries, errors);
 224
 225                 i = 0;
 226                 if(!found_0_1) {
 227                         while (i < n - 1) {
 228                                 if (IsBlock0PCF7931(tmp_blocks[i]) && IsBlock1PCF7931(tmp_blocks[i+1])) {
 229                                         found_0_1 = 1;
 230                                         memcpy(memory_blocks[0], tmp_blocks[i], 16);
 231                                         memcpy(memory_blocks[1], tmp_blocks[i+1], 16);
 232                                         memory_blocks[0][ALLOC] = memory_blocks[1][ALLOC] = 1;
 233                                         // block 1 tells how many blocks are going to be sent
 234                                         max_blocks = MAX((memory_blocks[1][14] & 0x7f), memory_blocks[1][15]) + 1;
 235                                         found_blocks = 2;
 236
 237                                         Dbprintf("Found blocks 0 and 1. PCF is transmitting %d blocks.", max_blocks);
 238
 239                                         // handle the following blocks
 240                                         for (j = i + 2; j < n; ++j) {
 241                                                 memcpy(memory_blocks[found_blocks], tmp_blocks[j], 16);
 242                                                 memory_blocks[found_blocks][ALLOC] = 1;
 243                                                 ++found_blocks;
 244                                         }
 245                                         break;
 246                                 }
 247                                 ++i;
 248                         }
 249                 } else {
 250                         // Trying to re-order blocks
 251                         // Look for identical block in memory blocks
 252                         while (i < n-1) {
 253                                 // skip all zeroes blocks
 254                                 if (memcmp(tmp_blocks[i], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) {
 255                                         for (j = 1; j < max_blocks - 1; ++j) {
 256                                                 if (!memcmp(tmp_blocks[i], memory_blocks[j], 16) && !memory_blocks[j+1][ALLOC]) {
 257                                                         memcpy(memory_blocks[j+1], tmp_blocks[i+1], 16);
 258                                                         memory_blocks[j+1][ALLOC] = 1;
 259                                                         if (++found_blocks >= max_blocks) goto end;
 260                                                 }
 261                                         }
 262                                 }
 263                                 if (memcmp(tmp_blocks[i+1], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) {
 264                                         for (j = 0; j < max_blocks; ++j) {
 265                                                 if (!memcmp(tmp_blocks[i+1], memory_blocks[j], 16) && !memory_blocks[(j == 0 ? max_blocks : j) -1][ALLOC]) {
 266                                                         if (j == 0) {
 267                                                                 memcpy(memory_blocks[max_blocks - 1], tmp_blocks[i], 16);
 268                                                                 memory_blocks[max_blocks - 1][ALLOC] = 1;
 269                                                         } else {
 270                                                                 memcpy(memory_blocks[j-1], tmp_blocks[i], 16);
 271                                                                 memory_blocks[j-1][ALLOC] = 1;
 272                                                         }
 273                                                         if (++found_blocks >= max_blocks) goto end;
 274                                                 }
 275                                         }
 276                                 }
 277                                 ++i;
 278                         }
 279                 }
 280                 ++tries;
 281                 if (BUTTON_PRESS()) {
 282                         Dbprintf("Button pressed, stopping.");
 283                         goto end;
 284                 }
 285         }
 286         while (found_blocks != max_blocks);
 287
 288  end:
 289         Dbprintf("-----------------------------------------");
 290         Dbprintf("Memory content:");
 291         Dbprintf("-----------------------------------------");
 292         for (i = 0; i < max_blocks; ++i) {
 293                 if (memory_blocks[i][ALLOC])
 294                         print_result("Block", memory_blocks[i], 16);
 295                 else
 296                         Dbprintf("<missing block %d>", i);
 297         }
 298         Dbprintf("-----------------------------------------");
 299
 300         if (found_blocks < max_blocks) {
 301                 Dbprintf("-----------------------------------------");
 302                 Dbprintf("Blocks with unknown position:");
 303                 Dbprintf("-----------------------------------------");
 304                 for (i = 0; i < single_blocks_cnt; ++i)
 305                         print_result("Block", single_blocks[i], 16);
 306
 307                 Dbprintf("-----------------------------------------");
 308         }
 309         cmd_send(CMD_ACK,0,0,0,0,0);
 310 }
 311
 312 static void RealWritePCF7931(uint8_t *pass, uint16_t init_delay, int32_t l, int32_t p, uint8_t address, uint8_t byte, uint8_t data) {
 313         uint32_t tab[1024]={0}; // data times frame
 314         uint32_t u = 0;
 315         uint8_t parity = 0;
 316         bool comp = 0;
 317
 318         //BUILD OF THE DATA FRAME
 319         //alimentation of the tag (time for initializing)
 320         AddPatternPCF7931(init_delay, 0, 8192/2*T0_PCF, tab);
 321         AddPatternPCF7931(8192/2*T0_PCF + 319*T0_PCF+70, 3*T0_PCF, 29*T0_PCF, tab);
 322         //password indication bit
 323         AddBitPCF7931(1, tab, l, p);
 324         // password (on 56 bits)
 325         AddBytePCF7931(pass[0], tab, l, p);
 326         AddBytePCF7931(pass[1], tab, l, p);
 327         AddBytePCF7931(pass[2], tab, l, p);
 328         AddBytePCF7931(pass[3], tab, l, p);
 329         AddBytePCF7931(pass[4], tab, l, p);
 330         AddBytePCF7931(pass[5], tab, l, p);
 331         AddBytePCF7931(pass[6], tab, l, p);
 332         //programming mode (0 or 1)
 333         AddBitPCF7931(0, tab, l, p);
 334
 335         //block adress on 6 bits
 336         for (u = 0; u < 6; ++u) {
 337                 if (address & (1 << u)) {       // bit 1
 338                          ++parity;
 339                          AddBitPCF7931(1, tab, l, p);
 340                 } else {                                        // bit 0
 341                          AddBitPCF7931(0, tab, l, p);
 342                 }
 343         }
 344
 345         //byte address on 4 bits
 346         for (u = 0; u < 4; ++u)
 347         {
 348                 if (byte & (1 << u)) {  // bit 1
 349                          parity++;
 350                          AddBitPCF7931(1, tab, l, p);
 351                 }
 352                 else                            // bit 0
 353                          AddBitPCF7931(0, tab, l, p);
 354         }
 355
 356         //data on 8 bits
 357         for (u=0; u<8; u++)
 358         {
 359                 if (data&(1<<u)) {      // bit 1
 360                          parity++;
 361                          AddBitPCF7931(1, tab, l, p);
 362                 }
 363                 else                            //bit 0
 364                          AddBitPCF7931(0, tab, l, p);
 365         }
 366
 367         //parity bit
 368         if ((parity % 2) == 0)
 369                 AddBitPCF7931(0, tab, l, p); //even parity
 370         else
 371                 AddBitPCF7931(1, tab, l, p);//odd parity
 372
 373         //time access memory
 374         AddPatternPCF7931(5120+2680, 0, 0, tab);
 375
 376         //conversion of the scale time
 377         for (u = 0; u < 500; ++u)
 378                 tab[u] = (tab[u] * 3) / 2;
 379
 380         //compennsation of the counter reload
 381         while (!comp) {
 382                 comp = 1;
 383                 for (u = 0; tab[u] != 0; ++u)
 384                         if(tab[u] > 0xFFFF) {
 385                           tab[u] -= 0xFFFF;
 386                           comp = 0;
 387                         }
 388         }
 389
 390         SendCmdPCF7931(tab);
 391 }
 392
 393 void BruteForcePCF7931(uint64_t password, uint8_t tries, uint16_t init_delay, int32_t l, int32_t p) {
 394         uint8_t i = 0;
 395         uint8_t pass_array[7];
 396
 397         while (password < 0x00FFFFFFFFFFFFFF) {
 398                 if (BUTTON_PRESS()) {
 399                         Dbprintf("Button pressed, stopping bruteforce ...");
 400                         return;
 401                 }
 402
 403                 pass_array[0] = password & 0xFF;
 404                 pass_array[1] = (password >> 8) & 0xFF;
 405                 pass_array[2] = (password >> 16) & 0xFF;
 406                 pass_array[3] = (password >> 24) & 0xFF;
 407                 pass_array[4] = (password >> 32) & 0xFF;
 408                 pass_array[5] = (password >> 40) & 0xFF;
 409                 pass_array[6] = (password >> 48) & 0xFF;
 410
 411                 Dbprintf("Trying: %02x %02x %02x %02x %02x %02x %02x ...",
 412                         pass_array[0],
 413                         pass_array[1],
 414                         pass_array[2],
 415                         pass_array[3],
 416                         pass_array[4],
 417                         pass_array[5],
 418                         pass_array[6]);
 419
 420                 for (i = 0; i < tries; ++i)
 421                         RealWritePCF7931
 422                         (
 423                                 pass_array,
 424                                 init_delay,
 425                                 l,
 426                                 p,
 427                                 0,
 428                                 7,
 429                                 0x01
 430                         );
 431
 432                 ++password;
 433         }
 434 }
 435
 436 /* Write on a byte of a PCF7931 tag
 437  * @param address : address of the block to write
 438    @param byte : address of the byte to write
 439     @param data : data to write
 440  */
 441 void WritePCF7931(uint8_t pass1, uint8_t pass2, uint8_t pass3, uint8_t pass4, uint8_t pass5, uint8_t pass6, uint8_t pass7, uint16_t init_delay, int32_t l, int32_t p, uint8_t address, uint8_t byte, uint8_t data) {
 442         Dbprintf("Initialization delay : %d us", init_delay);
 443         Dbprintf("Offsets : %d us on the low pulses width, %d us on the low pulses positions", l, p);
 444         Dbprintf("Password (LSB first on each byte): %02x %02x %02x %02x %02x %02x %02x", pass1, pass2, pass3, pass4, pass5, pass6, pass7);
 445         Dbprintf("Block address : %02x", address);
 446         Dbprintf("Byte address : %02x", byte);
 447         Dbprintf("Data : %02x", data);
 448
 449         uint8_t password[7] = {pass1, pass2, pass3, pass4, pass5, pass6, pass7};
 450
 451         RealWritePCF7931 (password, init_delay, l, p, address, byte, data);
 452 }
 453
 454
 455
 456 /* Send a trame to a PCF7931 tags
 457  * @param tab : array of the data frame
 458  */
 459
 460 void SendCmdPCF7931(uint32_t * tab) {
 461         uint16_t u=0;
 462         uint16_t tempo=0;
 463
 464         Dbprintf("Sending data frame ...");
 465
 466         FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
 467         FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
 468         FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU );
 469
 470         LED_A_ON();
 471
 472         // steal this pin from the SSP and use it to control the modulation
 473         AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
 474         AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
 475
 476         //initialization of the timer
 477         AT91C_BASE_PMC->PMC_PCER |= (0x1 << 12) | (0x1 << 13) | (0x1 << 14);
 478         AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE | AT91C_TCB_TC1XC1S_TIOA0 | AT91C_TCB_TC2XC2S_NONE;
 479         AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
 480         AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK;  //clock at 48/32 MHz
 481         AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN;
 482         AT91C_BASE_TCB->TCB_BCR = 1;
 483
 484         tempo = AT91C_BASE_TC0->TC_CV;
 485         for (u = 0; tab[u] !=  0; u += 3) {
 486                 // modulate antenna
 487                 HIGH(GPIO_SSC_DOUT);
 488                 while(tempo !=  tab[u])
 489                         tempo = AT91C_BASE_TC0->TC_CV;
 490
 491                 // stop modulating antenna
 492                 LOW(GPIO_SSC_DOUT);
 493                 while(tempo !=  tab[u+1])
 494                         tempo = AT91C_BASE_TC0->TC_CV;
 495
 496                 // modulate antenna
 497                 HIGH(GPIO_SSC_DOUT);
 498                 while(tempo !=  tab[u+2])
 499                         tempo = AT91C_BASE_TC0->TC_CV;
 500         }
 501
 502         LED_A_OFF();
 503         FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 504         SpinDelay(200);
 505
 506         AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
 507         DbpString("Data frame sent (multiple sends may be needed)");
 508         LED(0xFFFF, 1000);
 509 }
 510
 511
 512 /* Add a byte for building the data frame of PCF7931 tags
 513  * @param b : byte to add
 514  * @param tab : array of the data frame
 515  * @param l : offset on low pulse width
 516  * @param p : offset on low pulse positioning
 517  */
 518 bool AddBytePCF7931(uint8_t byte, uint32_t * tab, int32_t l, int32_t p) {
 519         uint32_t u;
 520         for (u = 0; u < 8; ++u) {
 521                 if (byte & (1 << u)) {  //bit is 1
 522                         if(AddBitPCF7931(1, tab, l, p)==1)return 1;
 523                 } else { //bit is 0
 524                         if(AddBitPCF7931(0, tab, l, p)==1)return 1;
 525                 }
 526         }
 527
 528         return 0;
 529 }
 530
 531 /* Add a bits for building the data frame of PCF7931 tags
 532  * @param b : bit to add
 533  * @param tab : array of the data frame
 534  * @param l : offset on low pulse width
 535  * @param p : offset on low pulse positioning
 536  */
 537 bool AddBitPCF7931(bool b, uint32_t * tab, int32_t l, int32_t p) {
 538         uint8_t u = 0;
 539
 540         for (u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array
 541
 542         if (b == 1) {   //add a bit 1
 543                 if (u == 0)     tab[u] = 34 * T0_PCF + p;
 544                 else            tab[u] = 34 * T0_PCF + tab[u-1] + p;
 545
 546                 tab[u+1] = 6 * T0_PCF+tab[u] + l;
 547                 tab[u+2] = 88 * T0_PCF+tab[u + 1] - l - p;
 548                 return 0;
 549         } else {                //add a bit 0
 550
 551                 if (u == 0)     tab[u] = 98 * T0_PCF + p;
 552                 else            tab[u] = 98 * T0_PCF + tab[u-1] + p;
 553
 554                 tab[u + 1] = 6 * T0_PCF + tab[u] + l;
 555                 tab[u + 2] = 24 * T0_PCF + tab[u + 1] - l - p;
 556                 return 0;
 557         }
 558
 559         return 1;
 560 }
 561
 562 /* Add a custom pattern in the data frame
 563  * @param a : delay of the first high pulse
 564  * @param b : delay of the low pulse
 565  * @param c : delay of the last high pulse
 566  * @param tab : array of the data frame
 567  */
 568 bool AddPatternPCF7931(uint32_t a, uint32_t b, uint32_t c, uint32_t * tab) {
 569         uint32_t u = 0;
 570         for(u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array
 571
 572         if (u == 0)     tab[u] = a;
 573         else            tab[u] = a + tab[u - 1];
 574
 575         tab[u + 1] = b + tab[u];
 576         tab[u + 2] = c + tab[u + 1];
 577
 578         return 0;
 579 }