git.zerfleddert.de Git - proxmark3-svn/blob - client/cmdlfem4x.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 // Low frequency EM4x commands
   9 //-----------------------------------------------------------------------------
  10
  11 #include <stdio.h>
  12 #include <string.h>
  13 #include <inttypes.h>
  14 #include "proxusb.h"
  15 #include "proxmark3.h"
  16 #include "ui.h"
  17 #include "graph.h"
  18 #include "cmdparser.h"
  19 #include "cmddata.h"
  20 #include "cmdlf.h"
  21 #include "cmdlfem4x.h"
  22
  23 static int CmdHelp(const char *Cmd);
  24
  25 /* Read the ID of an EM410x tag.
  26  * Format:
  27  *   1111 1111 1           <-- standard non-repeatable header
  28  *   XXXX [row parity bit] <-- 10 rows of 5 bits for our 40 bit tag ID
  29  *   ....
  30  *   CCCC                  <-- each bit here is parity for the 10 bits above in corresponding column
  31  *   0                     <-- stop bit, end of tag
  32  */
  33 int CmdEM410xRead(const char *Cmd)
  34 {
  35   int i, j, clock, header, rows, bit, hithigh, hitlow, first, bit2idx, high, low;
  36   int parity[4];
  37   char id[11];
  38   int retested = 0;
  39   uint8_t BitStream[MAX_GRAPH_TRACE_LEN];
  40   high = low = 0;
  41
  42   /* Detect high and lows and clock */
  43   for (i = 0; i < GraphTraceLen; i++)
  44   {
  45     if (GraphBuffer[i] > high)
  46       high = GraphBuffer[i];
  47     else if (GraphBuffer[i] < low)
  48       low = GraphBuffer[i];
  49   }
  50
  51   /* get clock */
  52   clock = GetClock(Cmd, high, 0);
  53
  54   /* parity for our 4 columns */
  55   parity[0] = parity[1] = parity[2] = parity[3] = 0;
  56   header = rows = 0;
  57
  58   /* manchester demodulate */
  59   bit = bit2idx = 0;
  60   for (i = 0; i < (int)(GraphTraceLen / clock); i++)
  61   {
  62     hithigh = 0;
  63     hitlow = 0;
  64     first = 1;
  65
  66     /* Find out if we hit both high and low peaks */
  67     for (j = 0; j < clock; j++)
  68     {
  69       if (GraphBuffer[(i * clock) + j] == high)
  70         hithigh = 1;
  71       else if (GraphBuffer[(i * clock) + j] == low)
  72         hitlow = 1;
  73
  74       /* it doesn't count if it's the first part of our read
  75        because it's really just trailing from the last sequence */
  76       if (first && (hithigh || hitlow))
  77         hithigh = hitlow = 0;
  78       else
  79         first = 0;
  80
  81       if (hithigh && hitlow)
  82         break;
  83     }
  84
  85     /* If we didn't hit both high and low peaks, we had a bit transition */
  86     if (!hithigh || !hitlow)
  87       bit ^= 1;
  88
  89     BitStream[bit2idx++] = bit;
  90   }
  91
  92 retest:
  93   /* We go till 5 before the graph ends because we'll get that far below */
  94   for (i = 1; i < bit2idx - 5; i++)
  95   {
  96     /* Step 2: We have our header but need our tag ID */
  97     if (header == 9 && rows < 10)
  98     {
  99       /* Confirm parity is correct */
 100       if ((BitStream[i] ^ BitStream[i+1] ^ BitStream[i+2] ^ BitStream[i+3]) == BitStream[i+4])
 101       {
 102         /* Read another byte! */
 103         sprintf(id+rows, "%x", (8 * BitStream[i]) + (4 * BitStream[i+1]) + (2 * BitStream[i+2]) + (1 * BitStream[i+3]));
 104         rows++;
 105
 106         /* Keep parity info */
 107         parity[0] ^= BitStream[i];
 108         parity[1] ^= BitStream[i+1];
 109         parity[2] ^= BitStream[i+2];
 110         parity[3] ^= BitStream[i+3];
 111
 112         /* Move 4 bits ahead */
 113         i += 4;
 114       }
 115
 116       /* Damn, something wrong! reset */
 117       else
 118       {
 119         PrintAndLog("Thought we had a valid tag but failed at word %d (i=%d)", rows + 1, i);
 120
 121         /* Start back rows * 5 + 9 header bits, -1 to not start at same place */
 122         i -= 9 + (5 * rows) - 5;
 123
 124         rows = header = 0;
 125       }
 126     }
 127
 128     /* Step 3: Got our 40 bits! confirm column parity */
 129     else if (rows == 10)
 130     {
 131       /* We need to make sure our 4 bits of parity are correct and we have a stop bit */
 132       if (BitStream[i] == parity[0] && BitStream[i+1] == parity[1] &&
 133         BitStream[i+2] == parity[2] && BitStream[i+3] == parity[3] &&
 134         BitStream[i+4] == 0)
 135       {
 136         /* Sweet! */
 137         PrintAndLog("EM410x Tag ID: %s", id);
 138
 139         /* Stop any loops */
 140         return 1;
 141       }
 142
 143       /* Crap! Incorrect parity or no stop bit, start all over */
 144       else
 145       {
 146         rows = header = 0;
 147
 148         /* Go back 59 bits (9 header bits + 10 rows at 4+1 parity) */
 149         i -= 59;
 150       }
 151     }
 152
 153     /* Step 1: get our header */
 154     else if (header < 9)
 155     {
 156       /* Need 9 consecutive 1's */
 157       if (BitStream[i] == 1)
 158         header++;
 159
 160       /* We don't have a header, not enough consecutive 1 bits */
 161       else
 162         header = 0;
 163     }
 164   }
 165
 166   /* if we've already retested after flipping bits, return */
 167   if (retested++)
 168     return 0;
 169
 170   /* if this didn't work, try flipping bits */
 171   for (i = 0; i < bit2idx; i++)
 172     BitStream[i] ^= 1;
 173
 174   goto retest;
 175 }
 176
 177 /* emulate an EM410X tag
 178  * Format:
 179  *   1111 1111 1           <-- standard non-repeatable header
 180  *   XXXX [row parity bit] <-- 10 rows of 5 bits for our 40 bit tag ID
 181  *   ....
 182  *   CCCC                  <-- each bit here is parity for the 10 bits above in corresponding column
 183  *   0                     <-- stop bit, end of tag
 184  */
 185 int CmdEM410xSim(const char *Cmd)
 186 {
 187   int i, n, j, h, binary[4], parity[4];
 188
 189   /* clock is 64 in EM410x tags */
 190   int clock = 64;
 191
 192   /* clear our graph */
 193   ClearGraph(0);
 194
 195   /* write it out a few times */
 196   for (h = 0; h < 4; h++)
 197   {
 198     /* write 9 start bits */
 199     for (i = 0; i < 9; i++)
 200       AppendGraph(0, clock, 1);
 201
 202     /* for each hex char */
 203     parity[0] = parity[1] = parity[2] = parity[3] = 0;
 204     for (i = 0; i < 10; i++)
 205     {
 206       /* read each hex char */
 207       sscanf(&Cmd[i], "%1x", &n);
 208       for (j = 3; j >= 0; j--, n/= 2)
 209         binary[j] = n % 2;
 210
 211       /* append each bit */
 212       AppendGraph(0, clock, binary[0]);
 213       AppendGraph(0, clock, binary[1]);
 214       AppendGraph(0, clock, binary[2]);
 215       AppendGraph(0, clock, binary[3]);
 216
 217       /* append parity bit */
 218       AppendGraph(0, clock, binary[0] ^ binary[1] ^ binary[2] ^ binary[3]);
 219
 220       /* keep track of column parity */
 221       parity[0] ^= binary[0];
 222       parity[1] ^= binary[1];
 223       parity[2] ^= binary[2];
 224       parity[3] ^= binary[3];
 225     }
 226
 227     /* parity columns */
 228     AppendGraph(0, clock, parity[0]);
 229     AppendGraph(0, clock, parity[1]);
 230     AppendGraph(0, clock, parity[2]);
 231     AppendGraph(0, clock, parity[3]);
 232
 233     /* stop bit */
 234     AppendGraph(0, clock, 0);
 235   }
 236
 237   /* modulate that biatch */
 238   CmdManchesterMod("");
 239
 240   /* booyah! */
 241   RepaintGraphWindow();
 242
 243   CmdLFSim("");
 244   return 0;
 245 }
 246
 247 /* Function is equivalent of loread + losamples + em410xread
 248  * looped until an EM410x tag is detected */
 249 int CmdEM410xWatch(const char *Cmd)
 250 {
 251   do
 252   {
 253     CmdLFRead("");
 254     CmdSamples("2000");
 255   } while ( ! CmdEM410xRead(""));
 256   return 0;
 257 }
 258
 259 /* Read the transmitted data of an EM4x50 tag
 260  * Format:
 261  *
 262  *  XXXXXXXX [row parity bit (even)] <- 8 bits plus parity
 263  *  XXXXXXXX [row parity bit (even)] <- 8 bits plus parity
 264  *  XXXXXXXX [row parity bit (even)] <- 8 bits plus parity
 265  *  XXXXXXXX [row parity bit (even)] <- 8 bits plus parity
 266  *  CCCCCCCC                         <- column parity bits
 267  *  0                                <- stop bit
 268  *  LW                               <- Listen Window
 269  *
 270  * This pattern repeats for every block of data being transmitted.
 271  * Transmission starts with two Listen Windows (LW - a modulated
 272  * pattern of 320 cycles each (32/32/128/64/64)).
 273  *
 274  * Note that this data may or may not be the UID. It is whatever data
 275  * is stored in the blocks defined in the control word First and Last
 276  * Word Read values. UID is stored in block 32.
 277  */
 278 int CmdEM4x50Read(const char *Cmd)
 279 {
 280   int i, j, startblock, skip, block, start, end, low, high;
 281   bool complete= false;
 282   int tmpbuff[MAX_GRAPH_TRACE_LEN / 64];
 283   char tmp[6];
 284
 285   high= low= 0;
 286   memset(tmpbuff, 0, MAX_GRAPH_TRACE_LEN / 64);
 287
 288   /* first get high and low values */
 289   for (i = 0; i < GraphTraceLen; i++)
 290   {
 291     if (GraphBuffer[i] > high)
 292       high = GraphBuffer[i];
 293     else if (GraphBuffer[i] < low)
 294       low = GraphBuffer[i];
 295   }
 296
 297   /* populate a buffer with pulse lengths */
 298   i= 0;
 299   j= 0;
 300   while (i < GraphTraceLen)
 301   {
 302     // measure from low to low
 303     while ((GraphBuffer[i] > low) && (i<GraphTraceLen))
 304       ++i;
 305     start= i;
 306     while ((GraphBuffer[i] < high) && (i<GraphTraceLen))
 307       ++i;
 308     while ((GraphBuffer[i] > low) && (i<GraphTraceLen))
 309       ++i;
 310     if (j>(MAX_GRAPH_TRACE_LEN/64)) {
 311       break;
 312     }
 313     tmpbuff[j++]= i - start;
 314   }
 315
 316   /* look for data start - should be 2 pairs of LW (pulses of 192,128) */
 317   start= -1;
 318   skip= 0;
 319   for (i= 0; i < j - 4 ; ++i)
 320   {
 321     skip += tmpbuff[i];
 322     if (tmpbuff[i] >= 190 && tmpbuff[i] <= 194)
 323       if (tmpbuff[i+1] >= 126 && tmpbuff[i+1] <= 130)
 324         if (tmpbuff[i+2] >= 190 && tmpbuff[i+2] <= 194)
 325           if (tmpbuff[i+3] >= 126 && tmpbuff[i+3] <= 130)
 326           {
 327             start= i + 3;
 328             break;
 329           }
 330   }
 331   startblock= i + 3;
 332
 333   /* skip over the remainder of the LW */
 334   skip += tmpbuff[i+1]+tmpbuff[i+2];
 335   while (skip < MAX_GRAPH_TRACE_LEN && GraphBuffer[skip] > low)
 336     ++skip;
 337   skip += 8;
 338
 339   /* now do it again to find the end */
 340   end= start;
 341   for (i += 3; i < j - 4 ; ++i)
 342   {
 343     end += tmpbuff[i];
 344     if (tmpbuff[i] >= 190 && tmpbuff[i] <= 194)
 345       if (tmpbuff[i+1] >= 126 && tmpbuff[i+1] <= 130)
 346         if (tmpbuff[i+2] >= 190 && tmpbuff[i+2] <= 194)
 347           if (tmpbuff[i+3] >= 126 && tmpbuff[i+3] <= 130)
 348           {
 349             complete= true;
 350             break;
 351           }
 352   }
 353
 354   if (start >= 0)
 355     PrintAndLog("Found data at sample: %i",skip);
 356   else
 357   {
 358     PrintAndLog("No data found!");
 359     PrintAndLog("Try again with more samples.");
 360     return 0;
 361   }
 362
 363   if (!complete)
 364   {
 365     PrintAndLog("*** Warning!");
 366     PrintAndLog("Partial data - no end found!");
 367     PrintAndLog("Try again with more samples.");
 368   }
 369
 370   /* get rid of leading crap */
 371   sprintf(tmp,"%i",skip);
 372   CmdLtrim(tmp);
 373
 374   /* now work through remaining buffer printing out data blocks */
 375   block= 0;
 376   i= startblock;
 377   while (block < 6)
 378   {
 379     PrintAndLog("Block %i:", block);
 380     // mandemod routine needs to be split so we can call it for data
 381     // just print for now for debugging
 382     CmdManchesterDemod("i 64");
 383     skip= 0;
 384     /* look for LW before start of next block */
 385     for ( ; i < j - 4 ; ++i)
 386     {
 387       skip += tmpbuff[i];
 388       if (tmpbuff[i] >= 190 && tmpbuff[i] <= 194)
 389         if (tmpbuff[i+1] >= 126 && tmpbuff[i+1] <= 130)
 390           break;
 391     }
 392     while (GraphBuffer[skip] > low)
 393       ++skip;
 394     skip += 8;
 395     sprintf(tmp,"%i",skip);
 396     CmdLtrim(tmp);
 397     start += skip;
 398     block++;
 399   }
 400   return 0;
 401 }
 402
 403 int CmdEM410xWrite(const char *Cmd)
 404 {
 405   uint64_t id = 0;
 406   unsigned int card;
 407
 408   sscanf(Cmd, "%" PRIx64 " %d", &id, &card);
 409
 410   if (id >= 0x10000000000) {
 411     PrintAndLog("Error! Given EM410x ID is longer than 40 bits.\n");
 412     return 0;
 413   }
 414
 415   if (card > 1) {
 416     PrintAndLog("Error! Bad card type selected.\n");
 417     return 0;
 418   }
 419
 420   PrintAndLog("Writing %s tag with UID 0x%010" PRIx64, card ? "T55x7":"T5555", id);
 421   UsbCommand c = {CMD_EM410X_WRITE_TAG, {card, (uint32_t)(id >> 32), (uint32_t)id}};
 422   SendCommand(&c);
 423
 424   return 0;
 425 }
 426
 427 static command_t CommandTable[] =
 428 {
 429   {"help",        CmdHelp,        1, "This help"},
 430   {"em410xread",  CmdEM410xRead,  1, "[clock rate] -- Extract ID from EM410x tag"},
 431   {"em410xsim",   CmdEM410xSim,   0, "<UID> -- Simulate EM410x tag"},
 432   {"em410xwatch", CmdEM410xWatch, 0, "Watches for EM410x tags"},
 433   {"em410xwrite", CmdEM410xWrite, 1, "<UID> <'0' T5555> <'1' T55x7> -- Write EM410x UID to T5555(Q5) or T55x7 tag"},
 434   {"em4x50read",  CmdEM4x50Read,  1, "Extract data from EM4x50 tag"},
 435   {NULL, NULL, 0, NULL}
 436 };
 437
 438 int CmdLFEM4X(const char *Cmd)
 439 {
 440   CmdsParse(CommandTable, Cmd);
 441   return 0;
 442 }
 443
 444 int CmdHelp(const char *Cmd)
 445 {
 446   CmdsHelp(CommandTable);
 447   return 0;
 448 }