mirror of
https://github.com/Proxmark/proxmark3.git
synced 2024-11-21 04:50:14 -08:00
116 lines
4.2 KiB
C
116 lines
4.2 KiB
C
//-----------------------------------------------------------------------------
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//
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// This code is licensed to you under the terms of the GNU GPL, version 2 or,
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// at your option, any later version. See the LICENSE.txt file for the text of
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// the license.
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//-----------------------------------------------------------------------------
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// Low frequency G Prox II tag commands
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// Biphase, rf/ , 96 bits (unknown key calc + some bits)
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//-----------------------------------------------------------------------------
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#include <stdio.h>
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#include <string.h>
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#include <inttypes.h>
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#include "cmdlfgproxii.h"
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#include "proxmark3.h"
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#include "ui.h"
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#include "util.h"
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#include "graph.h"
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#include "cmdparser.h"
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#include "cmddata.h"
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#include "cmdmain.h"
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#include "cmdlf.h"
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#include "lfdemod.h"
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static int CmdHelp(const char *Cmd);
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//by marshmellow
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//attempts to demodulate and identify a G_Prox_II verex/chubb card
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//WARNING: if it fails during some points it will destroy the DemodBuffer data
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// but will leave the GraphBuffer intact.
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//if successful it will push askraw data back to demod buffer ready for emulation
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int CmdG_Prox_II_Demod(const char *Cmd)
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{
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if (!ASKbiphaseDemod(Cmd, false)){
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if (g_debugMode) PrintAndLog("Error gProxII: ASKbiphaseDemod failed 1st try");
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return 0;
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}
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size_t size = DemodBufferLen;
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//call lfdemod.c demod for gProxII
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int ans = gProxII_Demod(DemodBuffer, &size);
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if (ans < 0){
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if (g_debugMode) PrintAndLog("Error gProxII_Demod");
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return 0;
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}
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//got a good demod of 96 bits
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uint8_t ByteStream[8] = {0x00};
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uint8_t xorKey=0;
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size_t startIdx = ans + 6; //start after 6 bit preamble
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uint8_t bits_no_spacer[90];
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//so as to not mess with raw DemodBuffer copy to a new sample array
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memcpy(bits_no_spacer, DemodBuffer + startIdx, 90);
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// remove the 18 (90/5=18) parity bits (down to 72 bits (96-6-18=72))
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size_t bitLen = removeParity(bits_no_spacer, 0, 5, 3, 90); //source, startloc, paritylen, ptype, length_to_run
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if (bitLen != 72) {
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if (g_debugMode) PrintAndLog("Error gProxII: spacer removal did not produce 72 bits: %u, start: %u", bitLen, startIdx);
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return 0;
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}
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// get key and then get all 8 bytes of payload decoded
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xorKey = (uint8_t)bytebits_to_byteLSBF(bits_no_spacer, 8);
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for (size_t idx = 0; idx < 8; idx++) {
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ByteStream[idx] = ((uint8_t)bytebits_to_byteLSBF(bits_no_spacer+8 + (idx*8),8)) ^ xorKey;
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if (g_debugMode) PrintAndLog("byte %u after xor: %02x", (unsigned int)idx, ByteStream[idx]);
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}
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//now ByteStream contains 8 Bytes (64 bits) of decrypted raw tag data
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//
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uint8_t fmtLen = ByteStream[0]>>2;
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uint32_t FC = 0;
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uint32_t Card = 0;
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//get raw 96 bits to print
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uint32_t raw1 = bytebits_to_byte(DemodBuffer+ans,32);
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uint32_t raw2 = bytebits_to_byte(DemodBuffer+ans+32, 32);
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uint32_t raw3 = bytebits_to_byte(DemodBuffer+ans+64, 32);
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if (fmtLen==36){
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FC = ((ByteStream[3] & 0x7F)<<7) | (ByteStream[4]>>1);
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Card = ((ByteStream[4]&1)<<19) | (ByteStream[5]<<11) | (ByteStream[6]<<3) | (ByteStream[7]>>5);
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PrintAndLog("G-Prox-II Found: FmtLen %d, FC %u, Card %u", (int)fmtLen, FC, Card);
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} else if(fmtLen==26){
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FC = ((ByteStream[3] & 0x7F)<<1) | (ByteStream[4]>>7);
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Card = ((ByteStream[4]&0x7F)<<9) | (ByteStream[5]<<1) | (ByteStream[6]>>7);
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PrintAndLog("G-Prox-II Found: FmtLen %d, FC %u, Card %u", (int)fmtLen, FC, Card);
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} else {
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PrintAndLog("Unknown G-Prox-II Fmt Found: FmtLen %d",(int)fmtLen);
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PrintAndLog("Decoded Raw: %s", sprint_hex(ByteStream, 8));
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}
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PrintAndLog("Raw: %08x%08x%08x", raw1,raw2,raw3);
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setDemodBuf(DemodBuffer, 96, ans);
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setClockGrid(g_DemodClock, g_DemodStartIdx + (ans*g_DemodClock));
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return 1;
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}
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//by marshmellow
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//see ASKDemod for what args are accepted
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int CmdG_Prox_II_Read(const char *Cmd) {
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// read lf silently
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lf_read(true, 10000);
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// demod and output viking ID
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return CmdG_Prox_II_Demod(Cmd);
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}
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static command_t CommandTable[] = {
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{"help", CmdHelp, 1, "This help"},
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{"demod", CmdG_Prox_II_Demod, 1, "Demodulate a G Prox II tag from the GraphBuffer"},
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{"read", CmdG_Prox_II_Read, 0, "Attempt to read and Extract tag data from the antenna"},
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{NULL, NULL, 0, NULL}
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};
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int CmdLF_G_Prox_II(const char *Cmd) {
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CmdsParse(CommandTable, Cmd);
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return 0;
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}
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int CmdHelp(const char *Cmd) {
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CmdsHelp(CommandTable);
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return 0;
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}
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