cvs.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, or, at your option, any later version.
  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 loclass.  If not, see <http://www.gnu.org/licenses/>.
  34  *
  35  *
  36  ****************************************************************************/
  37
  38 #include <stdint.h>
  39 #include <stdio.h>
  40 #include <string.h>
  41 #include "fileutils.h"
  42 #include "cipherutils.h"
  43 /**
  44  *
  45  * @brief Return and remove the first bit (x0) in the stream : <x0 x1 x2 x3 ... xn >
  46  * @param stream
  47  * @return
  48  */
  49 bool headBit( BitstreamIn *stream)
  50 {
  51         int bytepos = stream->position >> 3; // divide by 8
  52         int bitpos = (stream->position++) & 7; // mask out 00000111
  53         return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1;
  54 }
  55 /**
  56  * @brief Return and remove the last bit (xn) in the stream: <x0 x1 x2 ... xn>
  57  * @param stream
  58  * @return
  59  */
  60 bool tailBit( BitstreamIn *stream)
  61 {
  62         int bitpos = stream->numbits -1 - (stream->position++);
  63
  64         int bytepos= bitpos >> 3;
  65         bitpos &= 7;
  66         return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1;
  67 }
  68 /**
  69  * @brief Pushes bit onto the stream
  70  * @param stream
  71  * @param bit
  72  */
  73 void pushBit( BitstreamOut* stream, bool bit)
  74 {
  75         int bytepos = stream->position >> 3; // divide by 8
  76         int bitpos = stream->position & 7;
  77         *(stream->buffer+bytepos) |= (bit & 1) <<  (7 - bitpos);
  78         stream->position++;
  79         stream->numbits++;
  80 }
  81
  82 /**
  83  * @brief Pushes the lower six bits onto the stream
  84  * as b0 b1 b2 b3 b4 b5 b6
  85  * @param stream
  86  * @param bits
  87  */
  88 void push6bits( BitstreamOut* stream, uint8_t bits)
  89 {
  90         pushBit(stream, bits & 0x20);
  91         pushBit(stream, bits & 0x10);
  92         pushBit(stream, bits & 0x08);
  93         pushBit(stream, bits & 0x04);
  94         pushBit(stream, bits & 0x02);
  95         pushBit(stream, bits & 0x01);
  96 }
  97
  98 /**
  99  * @brief bitsLeft
 100  * @param stream
 101  * @return number of bits left in stream
 102  */
 103 int bitsLeft( BitstreamIn *stream)
 104 {
 105         return stream->numbits - stream->position;
 106 }
 107 /**
 108  * @brief numBits
 109  * @param stream
 110  * @return Number of bits stored in stream
 111  */
 112 int numBits(BitstreamOut *stream)
 113 {
 114         return stream->numbits;
 115 }
 116
 117 void x_num_to_bytes(uint64_t n, size_t len, uint8_t* dest)
 118 {
 119         while (len--) {
 120                 dest[len] = (uint8_t) n;
 121                 n >>= 8;
 122         }
 123 }
 124
 125 uint64_t x_bytes_to_num(uint8_t* src, size_t len)
 126 {
 127         uint64_t num = 0;
 128         while (len--)
 129         {
 130                 num = (num << 8) | (*src);
 131                 src++;
 132         }
 133         return num;
 134 }
 135 uint8_t reversebytes(uint8_t b) {
 136         b = (b & 0xF0) >> 4 | (b & 0x0F) << 4;
 137         b = (b & 0xCC) >> 2 | (b & 0x33) << 2;
 138         b = (b & 0xAA) >> 1 | (b & 0x55) << 1;
 139    return b;
 140 }
 141 void reverse_arraybytes(uint8_t* arr, size_t len)
 142 {
 143         uint8_t i;
 144         for( i =0; i< len ; i++)
 145         {
 146                 arr[i] = reversebytes(arr[i]);
 147         }
 148 }
 149 void reverse_arraycopy(uint8_t* arr, uint8_t* dest, size_t len)
 150 {
 151         uint8_t i;
 152         for( i =0; i< len ; i++)
 153         {
 154                 dest[i] = reversebytes(arr[i]);
 155         }
 156 }
 157
 158 void printarr(char * name, uint8_t* arr, int len)
 159 {
 160         int cx;
 161         size_t outsize = 40+strlen(name)+len*5;
 162         char* output = malloc(outsize);
 163         memset(output, 0,outsize);
 164
 165         int i ;
 166         cx = snprintf(output,outsize, "uint8_t %s[] = {", name);
 167         for(i =0 ;  i< len ; i++)
 168         {
 169                 cx += snprintf(output+cx,outsize-cx,"0x%02x,",*(arr+i));//5 bytes per byte
 170         }
 171         cx += snprintf(output+cx,outsize-cx,"};");
 172         prnlog(output);
 173         free(output);
 174 }
 175
 176 void printvar(char * name, uint8_t* arr, int len)
 177 {
 178         int cx;
 179         size_t outsize = 40+strlen(name)+len*2;
 180         char* output = malloc(outsize);
 181         memset(output, 0,outsize);
 182
 183         int i ;
 184         cx = snprintf(output,outsize,"%s = ", name);
 185         for(i =0 ;  i< len ; i++)
 186         {
 187                 cx += snprintf(output+cx,outsize-cx,"%02x",*(arr+i));//2 bytes per byte
 188         }
 189
 190         prnlog(output);
 191         free(output);
 192 }
 193
 194 void printarr_human_readable(char * title, uint8_t* arr, int len)
 195 {
 196         int cx;
 197         size_t outsize = 100+strlen(title)+len*4;
 198         char* output = malloc(outsize);
 199         memset(output, 0,outsize);
 200
 201
 202         int i;
 203         cx = snprintf(output,outsize,  "\n\t%s\n", title);
 204         for(i =0 ;  i< len ; i++)
 205         {
 206                 if(i % 16 == 0)
 207                         cx += snprintf(output+cx,outsize-cx,"\n%02x| ", i );
 208                 cx += snprintf(output+cx,outsize-cx, "%02x ",*(arr+i));
 209         }
 210         prnlog(output);
 211         free(output);
 212 }
 213
 214 //-----------------------------
 215 // Code for testing below
 216 //-----------------------------
 217
 218 #ifndef ON_DEVICE
 219 int testBitStream()
 220 {
 221         uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF};
 222         uint8_t output [] = {0,0,0,0,0,0,0,0};
 223         BitstreamIn in = { input, sizeof(input) * 8,0};
 224         BitstreamOut out ={ output, 0,0}
 225                                           ;
 226         while(bitsLeft(&in) > 0)
 227         {
 228                 pushBit(&out, headBit(&in));
 229                 //printf("Bits left: %d\n", bitsLeft(&in));
 230                 //printf("Bits out: %d\n", numBits(&out));
 231         }
 232         if(memcmp(input, output, sizeof(input)) == 0)
 233         {
 234                 prnlog("    Bitstream test 1 ok");
 235         }else
 236         {
 237                 prnlog("    Bitstream test 1 failed");
 238                 uint8_t i;
 239                 for(i = 0 ; i < sizeof(input) ; i++)
 240                 {
 241                         prnlog("    IN %02x, OUT %02x", input[i], output[i]);
 242                 }
 243                 return 1;
 244         }
 245         return 0;
 246 }
 247
 248 int testReversedBitstream()
 249 {
 250         uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF};
 251         uint8_t reverse [] = {0,0,0,0,0,0,0,0};
 252         uint8_t output [] = {0,0,0,0,0,0,0,0};
 253         BitstreamIn in = { input, sizeof(input) * 8,0};
 254         BitstreamOut out ={ output, 0,0};
 255         BitstreamIn reversed_in ={ reverse, sizeof(input)*8,0};
 256         BitstreamOut reversed_out ={ reverse,0 ,0};
 257
 258         while(bitsLeft(&in) > 0)
 259         {
 260                 pushBit(&reversed_out, tailBit(&in));
 261         }
 262         while(bitsLeft(&reversed_in) > 0)
 263         {
 264                 pushBit(&out, tailBit(&reversed_in));
 265         }
 266         if(memcmp(input, output, sizeof(input)) == 0)
 267         {
 268                 prnlog("    Bitstream test 2 ok");
 269         }else
 270         {
 271                 prnlog("    Bitstream test 2 failed");
 272                 uint8_t i;
 273                 for(i = 0 ; i < sizeof(input) ; i++)
 274                 {
 275                         prnlog("    IN %02x, MIDDLE: %02x, OUT %02x", input[i],reverse[i], output[i]);
 276                 }
 277                 return 1;
 278         }
 279         return 0;
 280 }
 281
 282
 283 int testCipherUtils(void)
 284 {
 285         prnlog("[+] Testing some internals...");
 286         int retval = 0;
 287         retval |= testBitStream();
 288         retval |= testReversedBitstream();
 289         return retval;
 290 }
 291 #endif