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a66fca86 1/*****************************************************************************
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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
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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
26f202e2 25 * by the Free Software Foundation, or, at your option, any later version.
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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
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33 * along with loclass. If not, see <http://www.gnu.org/licenses/>.
34 *
35 *
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36 ****************************************************************************/
37
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38#include <stdint.h>
39#include <stdio.h>
40#include <string.h>
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41#include "fileutils.h"
42#include "cipherutils.h"
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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 */
49bool 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 */
60bool 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 */
73void 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 */
88void 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 */
103int 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 */
112int numBits(BitstreamOut *stream)
113{
114 return stream->numbits;
115}
116
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117void 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
125uint64_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}
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135uint8_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}
141void 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}
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149void 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
158void 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);
c4c3af7c 173 free(output);
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174}
175
176void 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);
c4c3af7c 191 free(output);
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192}
193
194void 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);
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200
201
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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);
ca4714cd 211 free(output);
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212}
213
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214//-----------------------------
215// Code for testing below
216//-----------------------------
217
b67f7ec3 218#ifndef ON_DEVICE
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219int 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 {
3ad48540 234 prnlog(" Bitstream test 1 ok");
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235 }else
236 {
3ad48540 237 prnlog(" Bitstream test 1 failed");
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238 uint8_t i;
239 for(i = 0 ; i < sizeof(input) ; i++)
240 {
3ad48540 241 prnlog(" IN %02x, OUT %02x", input[i], output[i]);
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242 }
243 return 1;
244 }
245 return 0;
246}
247
248int 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 {
3ad48540 268 prnlog(" Bitstream test 2 ok");
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269 }else
270 {
3ad48540 271 prnlog(" Bitstream test 2 failed");
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272 uint8_t i;
273 for(i = 0 ; i < sizeof(input) ; i++)
274 {
3ad48540 275 prnlog(" IN %02x, MIDDLE: %02x, OUT %02x", input[i],reverse[i], output[i]);
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276 }
277 return 1;
278 }
279 return 0;
280}
281
282
283int testCipherUtils(void)
284{
3ad48540 285 prnlog("[+] Testing some internals...");
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286 int retval = 0;
287 retval |= testBitStream();
288 retval |= testReversedBitstream();
289 return retval;
290}
b67f7ec3 291#endif
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