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

   1 /*****************************************************************************
   2  * WARNING
   3  *
   4  * THIS CODE IS CREATED FOR EXPERIMENTATION AND EDUCATIONAL USE ONLY.
   5  *
   6  * USAGE OF THIS CODE IN OTHER WAYS MAY INFRINGE UPON THE INTELLECTUAL
   7  * PROPERTY OF OTHER PARTIES, SUCH AS INSIDE SECURE AND HID GLOBAL,
   8  * AND MAY EXPOSE YOU TO AN INFRINGEMENT ACTION FROM THOSE PARTIES.
   9  *
  10  * THIS CODE SHOULD NEVER BE USED TO INFRINGE PATENTS OR INTELLECTUAL PROPERTY RIGHTS.
  11  *
  12  *****************************************************************************
  13  *
  14  * This file is part of loclass. It is a reconstructon of the cipher engine
  15  * used in iClass, and RFID techology.
  16  *
  17  * The implementation is based on the work performed by
  18  * Flavio D. Garcia, Gerhard de Koning Gans, Roel Verdult and
  19  * Milosch Meriac in the paper "Dismantling IClass".
  20  *
  21  * Copyright (C) 2014 Martin Holst Swende
  22  *
  23  * This is free software: you can redistribute it and/or modify
  24  * it under the terms of the GNU General Public License version 2 as published
  25  * by the Free Software Foundation.
  26  *
  27  * This file is distributed in the hope that it will be useful,
  28  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  29  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  30  * GNU General Public License for more details.
  31  *
  32  * You should have received a copy of the GNU General Public License
  33  * along with IClassCipher.  If not, see <http://www.gnu.org/licenses/>.
  34  ****************************************************************************/
  35
  36 #include <stdint.h>
  37 #include <stdio.h>
  38 #include <string.h>
  39 #include "fileutils.h"
  40 #include "cipherutils.h"
  41 /**
  42  *
  43  * @brief Return and remove the first bit (x0) in the stream : <x0 x1 x2 x3 ... xn >
  44  * @param stream
  45  * @return
  46  */
  47 bool headBit( BitstreamIn *stream)
  48 {
  49         int bytepos = stream->position >> 3; // divide by 8
  50         int bitpos = (stream->position++) & 7; // mask out 00000111
  51         return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1;
  52 }
  53 /**
  54  * @brief Return and remove the last bit (xn) in the stream: <x0 x1 x2 ... xn>
  55  * @param stream
  56  * @return
  57  */
  58 bool tailBit( BitstreamIn *stream)
  59 {
  60         int bitpos = stream->numbits -1 - (stream->position++);
  61
  62         int bytepos= bitpos >> 3;
  63         bitpos &= 7;
  64         return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1;
  65 }
  66 /**
  67  * @brief Pushes bit onto the stream
  68  * @param stream
  69  * @param bit
  70  */
  71 void pushBit( BitstreamOut* stream, bool bit)
  72 {
  73         int bytepos = stream->position >> 3; // divide by 8
  74         int bitpos = stream->position & 7;
  75         *(stream->buffer+bytepos) |= (bit & 1) <<  (7 - bitpos);
  76         stream->position++;
  77         stream->numbits++;
  78 }
  79
  80 /**
  81  * @brief Pushes the lower six bits onto the stream
  82  * as b0 b1 b2 b3 b4 b5 b6
  83  * @param stream
  84  * @param bits
  85  */
  86 void push6bits( BitstreamOut* stream, uint8_t bits)
  87 {
  88         pushBit(stream, bits & 0x20);
  89         pushBit(stream, bits & 0x10);
  90         pushBit(stream, bits & 0x08);
  91         pushBit(stream, bits & 0x04);
  92         pushBit(stream, bits & 0x02);
  93         pushBit(stream, bits & 0x01);
  94 }
  95
  96 /**
  97  * @brief bitsLeft
  98  * @param stream
  99  * @return number of bits left in stream
 100  */
 101 int bitsLeft( BitstreamIn *stream)
 102 {
 103         return stream->numbits - stream->position;
 104 }
 105 /**
 106  * @brief numBits
 107  * @param stream
 108  * @return Number of bits stored in stream
 109  */
 110 int numBits(BitstreamOut *stream)
 111 {
 112         return stream->numbits;
 113 }
 114
 115 void x_num_to_bytes(uint64_t n, size_t len, uint8_t* dest)
 116 {
 117         while (len--) {
 118                 dest[len] = (uint8_t) n;
 119                 n >>= 8;
 120         }
 121 }
 122
 123 uint64_t x_bytes_to_num(uint8_t* src, size_t len)
 124 {
 125         uint64_t num = 0;
 126         while (len--)
 127         {
 128                 num = (num << 8) | (*src);
 129                 src++;
 130         }
 131         return num;
 132 }
 133 uint8_t reversebytes(uint8_t b) {
 134         b = (b & 0xF0) >> 4 | (b & 0x0F) << 4;
 135         b = (b & 0xCC) >> 2 | (b & 0x33) << 2;
 136         b = (b & 0xAA) >> 1 | (b & 0x55) << 1;
 137    return b;
 138 }
 139 void reverse_arraybytes(uint8_t* arr, size_t len)
 140 {
 141         uint8_t i;
 142         for( i =0; i< len ; i++)
 143         {
 144                 arr[i] = reversebytes(arr[i]);
 145         }
 146 }
 147 void reverse_arraycopy(uint8_t* arr, uint8_t* dest, size_t len)
 148 {
 149         uint8_t i;
 150         for( i =0; i< len ; i++)
 151         {
 152                 dest[i] = reversebytes(arr[i]);
 153         }
 154 }
 155
 156 void printarr(char * name, uint8_t* arr, int len)
 157 {
 158         int cx;
 159         size_t outsize = 40+strlen(name)+len*5;
 160         char* output = malloc(outsize);
 161         memset(output, 0,outsize);
 162
 163         int i ;
 164         cx = snprintf(output,outsize, "uint8_t %s[] = {", name);
 165         for(i =0 ;  i< len ; i++)
 166         {
 167                 cx += snprintf(output+cx,outsize-cx,"0x%02x,",*(arr+i));//5 bytes per byte
 168         }
 169         cx += snprintf(output+cx,outsize-cx,"};");
 170         prnlog(output);
 171 }
 172
 173 void printvar(char * name, uint8_t* arr, int len)
 174 {
 175         int cx;
 176         size_t outsize = 40+strlen(name)+len*2;
 177         char* output = malloc(outsize);
 178         memset(output, 0,outsize);
 179
 180         int i ;
 181         cx = snprintf(output,outsize,"%s = ", name);
 182         for(i =0 ;  i< len ; i++)
 183         {
 184                 cx += snprintf(output+cx,outsize-cx,"%02x",*(arr+i));//2 bytes per byte
 185         }
 186
 187         prnlog(output);
 188 }
 189
 190 void printarr_human_readable(char * title, uint8_t* arr, int len)
 191 {
 192         int cx;
 193         size_t outsize = 100+strlen(title)+len*4;
 194         char* output = malloc(outsize);
 195         memset(output, 0,outsize);
 196
 197
 198         int i;
 199         cx = snprintf(output,outsize,  "\n\t%s\n", title);
 200         for(i =0 ;  i< len ; i++)
 201         {
 202                 if(i % 16 == 0)
 203                         cx += snprintf(output+cx,outsize-cx,"\n%02x| ", i );
 204                 cx += snprintf(output+cx,outsize-cx, "%02x ",*(arr+i));
 205         }
 206         prnlog(output);
 207         free(output);
 208 }
 209
 210 //-----------------------------
 211 // Code for testing below
 212 //-----------------------------
 213
 214
 215 int testBitStream()
 216 {
 217         uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF};
 218         uint8_t output [] = {0,0,0,0,0,0,0,0};
 219         BitstreamIn in = { input, sizeof(input) * 8,0};
 220         BitstreamOut out ={ output, 0,0}
 221                                           ;
 222         while(bitsLeft(&in) > 0)
 223         {
 224                 pushBit(&out, headBit(&in));
 225                 //printf("Bits left: %d\n", bitsLeft(&in));
 226                 //printf("Bits out: %d\n", numBits(&out));
 227         }
 228         if(memcmp(input, output, sizeof(input)) == 0)
 229         {
 230                 prnlog("    Bitstream test 1 ok");
 231         }else
 232         {
 233                 prnlog("    Bitstream test 1 failed");
 234                 uint8_t i;
 235                 for(i = 0 ; i < sizeof(input) ; i++)
 236                 {
 237                         prnlog("    IN %02x, OUT %02x", input[i], output[i]);
 238                 }
 239                 return 1;
 240         }
 241         return 0;
 242 }
 243
 244 int testReversedBitstream()
 245 {
 246         uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF};
 247         uint8_t reverse [] = {0,0,0,0,0,0,0,0};
 248         uint8_t output [] = {0,0,0,0,0,0,0,0};
 249         BitstreamIn in = { input, sizeof(input) * 8,0};
 250         BitstreamOut out ={ output, 0,0};
 251         BitstreamIn reversed_in ={ reverse, sizeof(input)*8,0};
 252         BitstreamOut reversed_out ={ reverse,0 ,0};
 253
 254         while(bitsLeft(&in) > 0)
 255         {
 256                 pushBit(&reversed_out, tailBit(&in));
 257         }
 258         while(bitsLeft(&reversed_in) > 0)
 259         {
 260                 pushBit(&out, tailBit(&reversed_in));
 261         }
 262         if(memcmp(input, output, sizeof(input)) == 0)
 263         {
 264                 prnlog("    Bitstream test 2 ok");
 265         }else
 266         {
 267                 prnlog("    Bitstream test 2 failed");
 268                 uint8_t i;
 269                 for(i = 0 ; i < sizeof(input) ; i++)
 270                 {
 271                         prnlog("    IN %02x, MIDDLE: %02x, OUT %02x", input[i],reverse[i], output[i]);
 272                 }
 273                 return 1;
 274         }
 275         return 0;
 276 }
 277
 278
 279 int testCipherUtils(void)
 280 {
 281         prnlog("[+] Testing some internals...");
 282         int retval = 0;
 283         retval |= testBitStream();
 284         retval |= testReversedBitstream();
 285         return retval;
 286 }