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.
  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
  39 #include <stdint.h>
  40 #include <stdio.h>
  41 #include <string.h>
  42 #include "fileutils.h"
  43 #include "cipherutils.h"
  44 /**
  45  *
  46  * @brief Return and remove the first bit (x0) in the stream : <x0 x1 x2 x3 ... xn >
  47  * @param stream
  48  * @return
  49  */
  50 bool headBit( BitstreamIn *stream)
  51 {
  52         int bytepos = stream->position >> 3; // divide by 8
  53         int bitpos = (stream->position++) & 7; // mask out 00000111
  54         return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1;
  55 }
  56 /**
  57  * @brief Return and remove the last bit (xn) in the stream: <x0 x1 x2 ... xn>
  58  * @param stream
  59  * @return
  60  */
  61 bool tailBit( BitstreamIn *stream)
  62 {
  63         int bitpos = stream->numbits -1 - (stream->position++);
  64
  65         int bytepos= bitpos >> 3;
  66         bitpos &= 7;
  67         return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1;
  68 }
  69 /**
  70  * @brief Pushes bit onto the stream
  71  * @param stream
  72  * @param bit
  73  */
  74 void pushBit( BitstreamOut* stream, bool bit)
  75 {
  76         int bytepos = stream->position >> 3; // divide by 8
  77         int bitpos = stream->position & 7;
  78         *(stream->buffer+bytepos) |= (bit & 1) <<  (7 - bitpos);
  79         stream->position++;
  80         stream->numbits++;
  81 }
  82
  83 /**
  84  * @brief Pushes the lower six bits onto the stream
  85  * as b0 b1 b2 b3 b4 b5 b6
  86  * @param stream
  87  * @param bits
  88  */
  89 void push6bits( BitstreamOut* stream, uint8_t bits)
  90 {
  91         pushBit(stream, bits & 0x20);
  92         pushBit(stream, bits & 0x10);
  93         pushBit(stream, bits & 0x08);
  94         pushBit(stream, bits & 0x04);
  95         pushBit(stream, bits & 0x02);
  96         pushBit(stream, bits & 0x01);
  97 }
  98
  99 /**
 100  * @brief bitsLeft
 101  * @param stream
 102  * @return number of bits left in stream
 103  */
 104 int bitsLeft( BitstreamIn *stream)
 105 {
 106         return stream->numbits - stream->position;
 107 }
 108 /**
 109  * @brief numBits
 110  * @param stream
 111  * @return Number of bits stored in stream
 112  */
 113 int numBits(BitstreamOut *stream)
 114 {
 115         return stream->numbits;
 116 }
 117
 118 void x_num_to_bytes(uint64_t n, size_t len, uint8_t* dest)
 119 {
 120         while (len--) {
 121                 dest[len] = (uint8_t) n;
 122                 n >>= 8;
 123         }
 124 }
 125
 126 uint64_t x_bytes_to_num(uint8_t* src, size_t len)
 127 {
 128         uint64_t num = 0;
 129         while (len--)
 130         {
 131                 num = (num << 8) | (*src);
 132                 src++;
 133         }
 134         return num;
 135 }
 136 uint8_t reversebytes(uint8_t b) {
 137         b = (b & 0xF0) >> 4 | (b & 0x0F) << 4;
 138         b = (b & 0xCC) >> 2 | (b & 0x33) << 2;
 139         b = (b & 0xAA) >> 1 | (b & 0x55) << 1;
 140    return b;
 141 }
 142 void reverse_arraybytes(uint8_t* arr, size_t len)
 143 {
 144         uint8_t i;
 145         for( i =0; i< len ; i++)
 146         {
 147                 arr[i] = reversebytes(arr[i]);
 148         }
 149 }
 150 void reverse_arraycopy(uint8_t* arr, uint8_t* dest, size_t len)
 151 {
 152         uint8_t i;
 153         for( i =0; i< len ; i++)
 154         {
 155                 dest[i] = reversebytes(arr[i]);
 156         }
 157 }
 158
 159 void printarr(char * name, uint8_t* arr, int len)
 160 {
 161         int cx;
 162         size_t outsize = 40+strlen(name)+len*5;
 163         char* output = malloc(outsize);
 164         memset(output, 0,outsize);
 165
 166         int i ;
 167         cx = snprintf(output,outsize, "uint8_t %s[] = {", name);
 168         for(i =0 ;  i< len ; i++)
 169         {
 170                 cx += snprintf(output+cx,outsize-cx,"0x%02x,",*(arr+i));//5 bytes per byte
 171         }
 172         cx += snprintf(output+cx,outsize-cx,"};");
 173         prnlog(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 }
 192
 193 void printarr_human_readable(char * title, uint8_t* arr, int len)
 194 {
 195         int cx;
 196         size_t outsize = 100+strlen(title)+len*4;
 197         char* output = malloc(outsize);
 198         memset(output, 0,outsize);
 199
 200
 201         int i;
 202         cx = snprintf(output,outsize,  "\n\t%s\n", title);
 203         for(i =0 ;  i< len ; i++)
 204         {
 205                 if(i % 16 == 0)
 206                         cx += snprintf(output+cx,outsize-cx,"\n%02x| ", i );
 207                 cx += snprintf(output+cx,outsize-cx, "%02x ",*(arr+i));
 208         }
 209         prnlog(output);
 210 }
 211
 212 //-----------------------------
 213 // Code for testing below
 214 //-----------------------------
 215
 216
 217 int testBitStream()
 218 {
 219         uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF};
 220         uint8_t output [] = {0,0,0,0,0,0,0,0};
 221         BitstreamIn in = { input, sizeof(input) * 8,0};
 222         BitstreamOut out ={ output, 0,0}
 223                                           ;
 224         while(bitsLeft(&in) > 0)
 225         {
 226                 pushBit(&out, headBit(&in));
 227                 //printf("Bits left: %d\n", bitsLeft(&in));
 228                 //printf("Bits out: %d\n", numBits(&out));
 229         }
 230         if(memcmp(input, output, sizeof(input)) == 0)
 231         {
 232                 prnlog("    Bitstream test 1 ok");
 233         }else
 234         {
 235                 prnlog("    Bitstream test 1 failed");
 236                 uint8_t i;
 237                 for(i = 0 ; i < sizeof(input) ; i++)
 238                 {
 239                         prnlog("    IN %02x, OUT %02x", input[i], output[i]);
 240                 }
 241                 return 1;
 242         }
 243         return 0;
 244 }
 245
 246 int testReversedBitstream()
 247 {
 248         uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF};
 249         uint8_t reverse [] = {0,0,0,0,0,0,0,0};
 250         uint8_t output [] = {0,0,0,0,0,0,0,0};
 251         BitstreamIn in = { input, sizeof(input) * 8,0};
 252         BitstreamOut out ={ output, 0,0};
 253         BitstreamIn reversed_in ={ reverse, sizeof(input)*8,0};
 254         BitstreamOut reversed_out ={ reverse,0 ,0};
 255
 256         while(bitsLeft(&in) > 0)
 257         {
 258                 pushBit(&reversed_out, tailBit(&in));
 259         }
 260         while(bitsLeft(&reversed_in) > 0)
 261         {
 262                 pushBit(&out, tailBit(&reversed_in));
 263         }
 264         if(memcmp(input, output, sizeof(input)) == 0)
 265         {
 266                 prnlog("    Bitstream test 2 ok");
 267         }else
 268         {
 269                 prnlog("    Bitstream test 2 failed");
 270                 uint8_t i;
 271                 for(i = 0 ; i < sizeof(input) ; i++)
 272                 {
 273                         prnlog("    IN %02x, MIDDLE: %02x, OUT %02x", input[i],reverse[i], output[i]);
 274                 }
 275                 return 1;
 276         }
 277         return 0;
 278 }
 279
 280
 281 int testCipherUtils(void)
 282 {
 283         prnlog("[+] Testing some internals...");
 284         int retval = 0;
 285         retval |= testBitStream();
 286         retval |= testReversedBitstream();
 287         return retval;
 288 }