proxmark3/client/cmdlfparadox.c

//-----------------------------------------------------------------------------
//
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// Low frequency Paradox tag commands
// FSK2a, rf/50, 96 bits (completely known)
//-----------------------------------------------------------------------------
#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include "cmdlfparadox.h"
#include "proxmark3.h"
#include "ui.h"
#include "util.h"
#include "graph.h"
#include "cmdparser.h"
#include "cmddata.h"
#include "cmdlf.h"
#include "lfdemod.h"
static int CmdHelp(const char *Cmd);

int usage_lf_paradox_sim(void) {
    PrintAndLogEx(NORMAL, "Enables simulation of Paradox card with specified card number.");
    PrintAndLogEx(NORMAL, "Simulation runs until the button is pressed or another USB command is issued.");
    PrintAndLogEx(NORMAL, "The facility-code is 8-bit and the card number is 16-bit.  Larger values are truncated.");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Usage:  lf paradox sim [h] <Facility-Code> <Card-Number>");
    PrintAndLogEx(NORMAL, "Options:");
    PrintAndLogEx(NORMAL, "  h               : this help");
    PrintAndLogEx(NORMAL, "  <Facility-Code> :  8-bit value facility code");
    PrintAndLogEx(NORMAL, "  <Card Number>   : 16-bit value card number");
    PrintAndLogEx(NORMAL, "");
    PrintAndLogEx(NORMAL, "Examples:");
    PrintAndLogEx(NORMAL, "       lf paradox sim 123 11223");
    return 0;
}

// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
int detectParadox(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo, int *waveStartIdx) {
    //make sure buffer has data
    if (*size < 96 * 50) return -1;

    if (getSignalProperties()->isnoise) return -2;

    // FSK demodulator
    *size = fskdemod(dest, *size, 50, 1, 10, 8, waveStartIdx); // paradox fsk2a

    //did we get a good demod?
    if (*size < 96) return -3;

    // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
    size_t startIdx = 0;
    uint8_t preamble[] = {0, 0, 0, 0, 1, 1, 1, 1};
    if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
        return -4; //preamble not found

    size_t numStart = startIdx + sizeof(preamble);
    // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
    for (size_t idx = numStart; (idx - numStart) < *size - sizeof(preamble); idx += 2) {
        if (dest[idx] == dest[idx + 1])
            return -5; //not manchester data

        *hi2 = (*hi2 << 1) | (*hi >> 31);
        *hi = (*hi << 1) | (*lo >> 31);
        //Then, shift in a 0 or one into low
        *lo <<= 1;
        if (dest[idx] && !dest[idx + 1]) // 1 0
            *lo |= 1;
        else // 0 1
            *lo |= 0;
    }
    return (int)startIdx;
}

//by marshmellow
//Paradox Prox demod - FSK2a RF/50 with preamble of 00001111 (then manchester encoded)
//print full Paradox Prox ID and some bit format details if found
int CmdParadoxDemod(const char *Cmd) {
    //raw fsk demod no manchester decoding no start bit finding just get binary from wave
    uint8_t bits[MAX_GRAPH_TRACE_LEN] = {0};
    size_t size = getFromGraphBuf(bits);
    if (size == 0) {
        PrintAndLogEx(DEBUG, "DEBUG: Error - Paradox not enough samples");
        return 0;
    }

    uint32_t hi2 = 0, hi = 0, lo = 0;
    int waveIdx = 0;
    //get binary from fsk wave
    int idx = detectParadox(bits, &size, &hi2, &hi, &lo, &waveIdx);
    if (idx < 0) {

        if (idx == -1)
            PrintAndLogEx(DEBUG, "DEBUG: Error - Paradox not enough samples");
        else if (idx == -2)
            PrintAndLogEx(DEBUG, "DEBUG: Error - Paradox just noise detected");
        else if (idx == -3)
            PrintAndLogEx(DEBUG, "DEBUG: Error - Paradox problem during FSK demod");
        else if (idx == -4)
            PrintAndLogEx(DEBUG, "DEBUG: Error - Paradox preamble not found");
        else if (idx == -5)
            PrintAndLogEx(DEBUG, "DEBUG: Error - Paradox error in Manchester data, size %d", size);
        else
            PrintAndLogEx(DEBUG, "DEBUG: Error - Paradox error demoding fsk %d", idx);

        return 0;
    }

    setDemodBuff(bits, size, idx);
    setClockGrid(50, waveIdx + (idx * 50));

    if (hi2 == 0 && hi == 0 && lo == 0) {
        PrintAndLogEx(DEBUG, "DEBUG: Error - Paradox no value found");
        return 0;
    }

    uint32_t fc = ((hi & 0x3) << 6) | (lo >> 26);
    uint32_t cardnum = (lo >> 10) & 0xFFFF;
    uint32_t rawLo = bytebits_to_byte(bits + idx + 64, 32);
    uint32_t rawHi = bytebits_to_byte(bits + idx + 32, 32);
    uint32_t rawHi2 = bytebits_to_byte(bits + idx, 32);

    PrintAndLogEx(NORMAL, "Paradox TAG ID: %x%08x - FC: %d - Card: %d - Checksum: %02x - RAW: %08x%08x%08x",
                  hi >> 10,
                  (hi & 0x3) << 26 | (lo >> 10),
                  fc, cardnum,
                  (lo >> 2) & 0xFF,
                  rawHi2,
                  rawHi,
                  rawLo
                 );

    PrintAndLogEx(DEBUG, "DEBUG: Paradox idx: %d, len: %d, Printing Demod Buffer:", idx, size);
    if (g_debugMode)
        printDemodBuff();

    return 1;
}
//by marshmellow
//see ASKDemod for what args are accepted
int CmdParadoxRead(const char *Cmd) {
    lf_read(true, 10000);
    return CmdParadoxDemod(Cmd);
}

int CmdParadoxSim(const char *Cmd) {

    char cmdp = tolower(param_getchar(Cmd, 0));
    if (strlen(Cmd) == 0 || cmdp == 'h') return usage_lf_paradox_sim();

    uint32_t facilitycode = 0, cardnumber = 0, fc = 0, cn = 0;

    uint8_t bs[96];
    size_t size = sizeof(bs);
    memset(bs, 0x00, size);

    // Paradox uses:  fcHigh: 10, fcLow: 8, clk: 50, invert: 1  FSK2a
    uint8_t clk = 50, invert = 1, high = 10, low = 8;
    uint16_t arg1, arg2;
    arg1 = high << 8 | low;
    arg2 = invert << 8 | clk;

    if (sscanf(Cmd, "%u %u", &fc, &cn) != 2) return usage_lf_paradox_sim();

    facilitycode = (fc & 0x000000FF);
    cardnumber = (cn & 0x0000FFFF);

    // if ( !GetParadoxBits(facilitycode, cardnumber, bs)) {
    // PrintAndLogEx(WARNING, "Error with tag bitstream generation.");
    // return 1;
    // }

    PrintAndLogEx(NORMAL, "Simulating Paradox - Facility Code: %u, CardNumber: %u", facilitycode, cardnumber);

    UsbCommand c = {CMD_FSK_SIM_TAG, {arg1, arg2, size}};
    memcpy(c.d.asBytes, bs, size);
    clearCommandBuffer();
    SendCommand(&c);

    PrintAndLogEx(NORMAL, "UNFINISHED");
    return 0;
}

static command_t CommandTable[] = {
    {"help",  CmdHelp,          1, "This help"},
    {"demod", CmdParadoxDemod,  1, "Demodulate a Paradox FSK tag from the GraphBuffer"},
    {"read",  CmdParadoxRead,   0, "Attempt to read and Extract tag data from the antenna"},
//  {"clone", CmdParadoxClone,  0, "clone paradox tag"},
    {"sim",   CmdParadoxSim,    0, "simulate paradox tag"},
    {NULL, NULL, 0, NULL}
};

int CmdLFParadox(const char *Cmd) {
    clearCommandBuffer();
    CmdsParse(CommandTable, Cmd);
    return 0;
}

int CmdHelp(const char *Cmd) {
    CmdsHelp(CommandTable);
    return 0;
}