/*****************************************************************************
* WARNING
*
* THIS CODE IS CREATED FOR EXPERIMENTATION AND EDUCATIONAL USE ONLY.
*
* USAGE OF THIS CODE IN OTHER WAYS MAY INFRINGE UPON THE INTELLECTUAL
* PROPERTY OF OTHER PARTIES, SUCH AS INSIDE SECURE AND HID GLOBAL,
* AND MAY EXPOSE YOU TO AN INFRINGEMENT ACTION FROM THOSE PARTIES.
*
* THIS CODE SHOULD NEVER BE USED TO INFRINGE PATENTS OR INTELLECTUAL PROPERTY RIGHTS.
*
*****************************************************************************
*
* This file is part of loclass. It is a reconstructon of the cipher engine
* used in iClass, and RFID techology.
*
* The implementation is based on the work performed by
* Flavio D. Garcia, Gerhard de Koning Gans, Roel Verdult and
* Milosch Meriac in the paper "Dismantling IClass".
*
* Copyright (C) 2014 Martin Holst Swende
*
* This is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* This file is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with loclass. If not, see <http://www.gnu.org/licenses/>.
*
*
*
****************************************************************************/
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include "fileutils.h"
#include "cipherutils.h"
/**
*
* @brief Return and remove the first bit (x0) in the stream : <x0 x1 x2 x3 ... xn >
* @param stream
* @return
*/
bool headBit( BitstreamIn *stream)
{
int bytepos = stream->position >> 3; // divide by 8
int bitpos = (stream->position++) & 7; // mask out 00000111
return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1;
}
/**
* @brief Return and remove the last bit (xn) in the stream: <x0 x1 x2 ... xn>
* @param stream
* @return
*/
bool tailBit( BitstreamIn *stream)
{
int bitpos = stream->numbits -1 - (stream->position++);
int bytepos= bitpos >> 3;
bitpos &= 7;
return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1;
}
/**
* @brief Pushes bit onto the stream
* @param stream
* @param bit
*/
void pushBit( BitstreamOut* stream, bool bit)
{
int bytepos = stream->position >> 3; // divide by 8
int bitpos = stream->position & 7;
*(stream->buffer+bytepos) |= (bit & 1) << (7 - bitpos);
stream->position++;
stream->numbits++;
}
/**
* @brief Pushes the lower six bits onto the stream
* as b0 b1 b2 b3 b4 b5 b6
* @param stream
* @param bits
*/
void push6bits( BitstreamOut* stream, uint8_t bits)
{
pushBit(stream, bits & 0x20);
pushBit(stream, bits & 0x10);
pushBit(stream, bits & 0x08);
pushBit(stream, bits & 0x04);
pushBit(stream, bits & 0x02);
pushBit(stream, bits & 0x01);
}
/**
* @brief bitsLeft
* @param stream
* @return number of bits left in stream
*/
int bitsLeft( BitstreamIn *stream)
{
return stream->numbits - stream->position;
}
/**
* @brief numBits
* @param stream
* @return Number of bits stored in stream
*/
int numBits(BitstreamOut *stream)
{
return stream->numbits;
}
void x_num_to_bytes(uint64_t n, size_t len, uint8_t* dest)
{
while (len--) {
dest[len] = (uint8_t) n;
n >>= 8;
}
}
uint64_t x_bytes_to_num(uint8_t* src, size_t len)
{
uint64_t num = 0;
while (len--)
{
num = (num << 8) | (*src);
src++;
}
return num;
}
uint8_t reversebytes(uint8_t b) {
b = (b & 0xF0) >> 4 | (b & 0x0F) << 4;
b = (b & 0xCC) >> 2 | (b & 0x33) << 2;
b = (b & 0xAA) >> 1 | (b & 0x55) << 1;
return b;
}
void reverse_arraybytes(uint8_t* arr, size_t len)
{
uint8_t i;
for( i =0; i< len ; i++)
{
arr[i] = reversebytes(arr[i]);
}
}
void reverse_arraycopy(uint8_t* arr, uint8_t* dest, size_t len)
{
uint8_t i;
for( i =0; i< len ; i++)
{
dest[i] = reversebytes(arr[i]);
}
}
void printarr(char * name, uint8_t* arr, int len)
{
int cx;
size_t outsize = 40+strlen(name)+len*5;
char* output = malloc(outsize);
memset(output, 0,outsize);
int i ;
cx = snprintf(output,outsize, "uint8_t %s[] = {", name);
for(i =0 ; i< len ; i++)
{
cx += snprintf(output+cx,outsize-cx,"0x%02x,",*(arr+i));//5 bytes per byte
}
cx += snprintf(output+cx,outsize-cx,"};");
prnlog(output);
free(output);
}
void printvar(char * name, uint8_t* arr, int len)
{
int cx;
size_t outsize = 40+strlen(name)+len*2;
char* output = malloc(outsize);
memset(output, 0,outsize);
int i ;
cx = snprintf(output,outsize,"%s = ", name);
for(i =0 ; i< len ; i++)
{
cx += snprintf(output+cx,outsize-cx,"%02x",*(arr+i));//2 bytes per byte
}
prnlog(output);
free(output);
}
void printarr_human_readable(char * title, uint8_t* arr, int len)
{
int cx;
size_t outsize = 100+strlen(title)+len*4;
char* output = malloc(outsize);
memset(output, 0,outsize);
int i;
cx = snprintf(output,outsize, "\n\t%s\n", title);
for(i =0 ; i< len ; i++)
{
if(i % 16 == 0)
cx += snprintf(output+cx,outsize-cx,"\n%02x| ", i );
cx += snprintf(output+cx,outsize-cx, "%02x ",*(arr+i));
}
prnlog(output);
free(output);
}
//-----------------------------
// Code for testing below
//-----------------------------
#ifndef ON_DEVICE
int testBitStream()
{
uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF};
uint8_t output [] = {0,0,0,0,0,0,0,0};
BitstreamIn in = { input, sizeof(input) * 8,0};
BitstreamOut out ={ output, 0,0}
;
while(bitsLeft(&in) > 0)
{
pushBit(&out, headBit(&in));
//printf("Bits left: %d\n", bitsLeft(&in));
//printf("Bits out: %d\n", numBits(&out));
}
if(memcmp(input, output, sizeof(input)) == 0)
{
prnlog(" Bitstream test 1 ok");
}else
{
prnlog(" Bitstream test 1 failed");
uint8_t i;
for(i = 0 ; i < sizeof(input) ; i++)
{
prnlog(" IN %02x, OUT %02x", input[i], output[i]);
}
return 1;
}
return 0;
}
int testReversedBitstream()
{
uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF};
uint8_t reverse [] = {0,0,0,0,0,0,0,0};
uint8_t output [] = {0,0,0,0,0,0,0,0};
BitstreamIn in = { input, sizeof(input) * 8,0};
BitstreamOut out ={ output, 0,0};
BitstreamIn reversed_in ={ reverse, sizeof(input)*8,0};
BitstreamOut reversed_out ={ reverse,0 ,0};
while(bitsLeft(&in) > 0)
{
pushBit(&reversed_out, tailBit(&in));
}
while(bitsLeft(&reversed_in) > 0)
{
pushBit(&out, tailBit(&reversed_in));
}
if(memcmp(input, output, sizeof(input)) == 0)
{
prnlog(" Bitstream test 2 ok");
}else
{
prnlog(" Bitstream test 2 failed");
uint8_t i;
for(i = 0 ; i < sizeof(input) ; i++)
{
prnlog(" IN %02x, MIDDLE: %02x, OUT %02x", input[i],reverse[i], output[i]);
}
return 1;
}
return 0;
}
int testCipherUtils(void)
{
prnlog("[+] Testing some internals...");
int retval = 0;
retval |= testBitStream();
retval |= testReversedBitstream();
return retval;
}
#endif