git.zerfleddert.de Git - proxmark3-svn/blob - client/cmdlfgproxii.c

   1 //-----------------------------------------------------------------------------
   2 //
   3 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
   4 // at your option, any later version. See the LICENSE.txt file for the text of
   5 // the license.
   6 //-----------------------------------------------------------------------------
   7 // Low frequency G Prox II tag commands
   8 //-----------------------------------------------------------------------------
   9 #include <stdio.h>
  10 #include <string.h>
  11 #include <inttypes.h>
  12 #include "cmdlfgproxii.h"
  13 #include "proxmark3.h"
  14 #include "ui.h"
  15 #include "util.h"
  16 #include "graph.h"
  17 #include "cmdparser.h"
  18 #include "cmddata.h"
  19 #include "cmdmain.h"
  20 #include "cmdlf.h"
  21 #include "lfdemod.h"
  22 static int CmdHelp(const char *Cmd);
  23
  24 //by marshmellow
  25 //attempts to demodulate and identify a G_Prox_II verex/chubb card
  26 //WARNING: if it fails during some points it will destroy the DemodBuffer data
  27 // but will leave the GraphBuffer intact.
  28 //if successful it will push askraw data back to demod buffer ready for emulation
  29 int CmdG_Prox_II_Demod(const char *Cmd)
  30 {
  31         if (!ASKbiphaseDemod(Cmd, false)){
  32                 if (g_debugMode) PrintAndLog("Error gProxII: ASKbiphaseDemod failed 1st try");
  33                 return 0;
  34         }
  35         size_t size = DemodBufferLen;
  36         //call lfdemod.c demod for gProxII
  37         int ans = gProxII_Demod(DemodBuffer, &size);
  38         if (ans < 0){
  39                 if (g_debugMode) PrintAndLog("Error gProxII_Demod");
  40                 return 0;
  41         }
  42         //got a good demod of 96 bits
  43         uint8_t ByteStream[8] = {0x00};
  44         uint8_t xorKey=0;
  45         size_t startIdx = ans + 6; //start after 6 bit preamble
  46
  47         uint8_t bits_no_spacer[90];
  48         //so as to not mess with raw DemodBuffer copy to a new sample array
  49         memcpy(bits_no_spacer, DemodBuffer + startIdx, 90);
  50         // remove the 18 (90/5=18) parity bits (down to 72 bits (96-6-18=72))
  51         size_t bitLen = removeParity(bits_no_spacer, 0, 5, 3, 90); //source, startloc, paritylen, ptype, length_to_run
  52         if (bitLen != 72) {
  53                 if (g_debugMode) PrintAndLog("Error gProxII: spacer removal did not produce 72 bits: %u, start: %u", bitLen, startIdx);
  54                 return 0;
  55         }
  56         // get key and then get all 8 bytes of payload decoded
  57         xorKey = (uint8_t)bytebits_to_byteLSBF(bits_no_spacer, 8);
  58         for (size_t idx = 0; idx < 8; idx++) {
  59                 ByteStream[idx] = ((uint8_t)bytebits_to_byteLSBF(bits_no_spacer+8 + (idx*8),8)) ^ xorKey;
  60                 if (g_debugMode) PrintAndLog("byte %u after xor: %02x", (unsigned int)idx, ByteStream[idx]);
  61         }
  62         //now ByteStream contains 8 Bytes (64 bits) of decrypted raw tag data
  63         //
  64         uint8_t fmtLen = ByteStream[0]>>2;
  65         uint32_t FC = 0;
  66         uint32_t Card = 0;
  67         //get raw 96 bits to print
  68         uint32_t raw1 = bytebits_to_byte(DemodBuffer+ans,32);
  69         uint32_t raw2 = bytebits_to_byte(DemodBuffer+ans+32, 32);
  70         uint32_t raw3 = bytebits_to_byte(DemodBuffer+ans+64, 32);
  71
  72         if (fmtLen==36){
  73                 FC = ((ByteStream[3] & 0x7F)<<7) | (ByteStream[4]>>1);
  74                 Card = ((ByteStream[4]&1)<<19) | (ByteStream[5]<<11) | (ByteStream[6]<<3) | (ByteStream[7]>>5);
  75                 PrintAndLog("G-Prox-II Found: FmtLen %d, FC %u, Card %u", (int)fmtLen, FC, Card);
  76         } else if(fmtLen==26){
  77                 FC = ((ByteStream[3] & 0x7F)<<1) | (ByteStream[4]>>7);
  78                 Card = ((ByteStream[4]&0x7F)<<9) | (ByteStream[5]<<1) | (ByteStream[6]>>7);
  79                 PrintAndLog("G-Prox-II Found: FmtLen %d, FC %u, Card %u", (int)fmtLen, FC, Card);
  80         } else {
  81                 PrintAndLog("Unknown G-Prox-II Fmt Found: FmtLen %d",(int)fmtLen);
  82                 PrintAndLog("Decoded Raw: %s", sprint_hex(ByteStream, 8));
  83         }
  84         PrintAndLog("Raw: %08x%08x%08x", raw1,raw2,raw3);
  85         setDemodBuf(DemodBuffer+ans, 96, 0);
  86         return 1;
  87 }
  88 //by marshmellow
  89 //see ASKDemod for what args are accepted
  90 int CmdG_Prox_II_Read(const char *Cmd) {
  91         // read lf silently
  92         CmdLFRead("s");
  93         // get samples silently
  94         getSamples("10000",false);
  95         // demod and output viking ID
  96         return CmdG_Prox_II_Demod(Cmd);
  97 }
  98
  99 static command_t CommandTable[] = {
 100         {"help",  CmdHelp,            1, "This help"},
 101         {"demod", CmdG_Prox_II_Demod, 1, "Demodulate a G Prox II tag from the GraphBuffer"},
 102         {"read",  CmdG_Prox_II_Read,  0, "Attempt to read and Extract tag data from the antenna"},
 103         {NULL, NULL, 0, NULL}
 104 };
 105
 106 int CmdLF_G_Prox_II(const char *Cmd) {
 107         CmdsParse(CommandTable, Cmd);
 108         return 0;
 109 }
 110
 111 int CmdHelp(const char *Cmd) {
 112         CmdsHelp(CommandTable);
 113         return 0;
 114 }