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1 | /***************************************************************************** |
2 | * This file is part of iClassCipher. It is a reconstructon of the cipher engine | |
3 | * used in iClass, and RFID techology. | |
4 | * | |
5 | * The implementation is based on the work performed by | |
6 | * Flavio D. Garcia, Gerhard de Koning Gans, Roel Verdult and | |
7 | * Milosch Meriac in the paper "Dismantling IClass". | |
8 | * | |
9 | * Copyright (C) 2014 Martin Holst Swende | |
10 | * | |
11 | * This is free software: you can redistribute it and/or modify | |
12 | * it under the terms of the GNU General Public License version 2 as published | |
13 | * by the Free Software Foundation. | |
14 | * | |
15 | * This file is distributed in the hope that it will be useful, | |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | * GNU General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License | |
21 | * along with IClassCipher. If not, see <http://www.gnu.org/licenses/>. | |
22 | ****************************************************************************/ | |
23 | ||
a66fca86 AD |
24 | #include <stdint.h> |
25 | #include <stdio.h> | |
26 | #include <string.h> | |
3ad48540 MHS |
27 | #include "fileutils.h" |
28 | #include "cipherutils.h" | |
a66fca86 AD |
29 | /** |
30 | * | |
31 | * @brief Return and remove the first bit (x0) in the stream : <x0 x1 x2 x3 ... xn > | |
32 | * @param stream | |
33 | * @return | |
34 | */ | |
35 | bool headBit( BitstreamIn *stream) | |
36 | { | |
37 | int bytepos = stream->position >> 3; // divide by 8 | |
38 | int bitpos = (stream->position++) & 7; // mask out 00000111 | |
39 | return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1; | |
40 | } | |
41 | /** | |
42 | * @brief Return and remove the last bit (xn) in the stream: <x0 x1 x2 ... xn> | |
43 | * @param stream | |
44 | * @return | |
45 | */ | |
46 | bool tailBit( BitstreamIn *stream) | |
47 | { | |
48 | int bitpos = stream->numbits -1 - (stream->position++); | |
49 | ||
50 | int bytepos= bitpos >> 3; | |
51 | bitpos &= 7; | |
52 | return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1; | |
53 | } | |
54 | /** | |
55 | * @brief Pushes bit onto the stream | |
56 | * @param stream | |
57 | * @param bit | |
58 | */ | |
59 | void pushBit( BitstreamOut* stream, bool bit) | |
60 | { | |
61 | int bytepos = stream->position >> 3; // divide by 8 | |
62 | int bitpos = stream->position & 7; | |
63 | *(stream->buffer+bytepos) |= (bit & 1) << (7 - bitpos); | |
64 | stream->position++; | |
65 | stream->numbits++; | |
66 | } | |
67 | ||
68 | /** | |
69 | * @brief Pushes the lower six bits onto the stream | |
70 | * as b0 b1 b2 b3 b4 b5 b6 | |
71 | * @param stream | |
72 | * @param bits | |
73 | */ | |
74 | void push6bits( BitstreamOut* stream, uint8_t bits) | |
75 | { | |
76 | pushBit(stream, bits & 0x20); | |
77 | pushBit(stream, bits & 0x10); | |
78 | pushBit(stream, bits & 0x08); | |
79 | pushBit(stream, bits & 0x04); | |
80 | pushBit(stream, bits & 0x02); | |
81 | pushBit(stream, bits & 0x01); | |
82 | } | |
83 | ||
84 | /** | |
85 | * @brief bitsLeft | |
86 | * @param stream | |
87 | * @return number of bits left in stream | |
88 | */ | |
89 | int bitsLeft( BitstreamIn *stream) | |
90 | { | |
91 | return stream->numbits - stream->position; | |
92 | } | |
93 | /** | |
94 | * @brief numBits | |
95 | * @param stream | |
96 | * @return Number of bits stored in stream | |
97 | */ | |
98 | int numBits(BitstreamOut *stream) | |
99 | { | |
100 | return stream->numbits; | |
101 | } | |
102 | ||
3ad48540 MHS |
103 | void x_num_to_bytes(uint64_t n, size_t len, uint8_t* dest) |
104 | { | |
105 | while (len--) { | |
106 | dest[len] = (uint8_t) n; | |
107 | n >>= 8; | |
108 | } | |
109 | } | |
110 | ||
111 | uint64_t x_bytes_to_num(uint8_t* src, size_t len) | |
112 | { | |
113 | uint64_t num = 0; | |
114 | while (len--) | |
115 | { | |
116 | num = (num << 8) | (*src); | |
117 | src++; | |
118 | } | |
119 | return num; | |
120 | } | |
a66fca86 AD |
121 | uint8_t reversebytes(uint8_t b) { |
122 | b = (b & 0xF0) >> 4 | (b & 0x0F) << 4; | |
123 | b = (b & 0xCC) >> 2 | (b & 0x33) << 2; | |
124 | b = (b & 0xAA) >> 1 | (b & 0x55) << 1; | |
125 | return b; | |
126 | } | |
127 | void reverse_arraybytes(uint8_t* arr, size_t len) | |
128 | { | |
129 | uint8_t i; | |
130 | for( i =0; i< len ; i++) | |
131 | { | |
132 | arr[i] = reversebytes(arr[i]); | |
133 | } | |
134 | } | |
3ad48540 MHS |
135 | void reverse_arraycopy(uint8_t* arr, uint8_t* dest, size_t len) |
136 | { | |
137 | uint8_t i; | |
138 | for( i =0; i< len ; i++) | |
139 | { | |
140 | dest[i] = reversebytes(arr[i]); | |
141 | } | |
142 | } | |
143 | ||
144 | void printarr(char * name, uint8_t* arr, int len) | |
145 | { | |
146 | int cx; | |
147 | size_t outsize = 40+strlen(name)+len*5; | |
148 | char* output = malloc(outsize); | |
149 | memset(output, 0,outsize); | |
150 | ||
151 | int i ; | |
152 | cx = snprintf(output,outsize, "uint8_t %s[] = {", name); | |
153 | for(i =0 ; i< len ; i++) | |
154 | { | |
155 | cx += snprintf(output+cx,outsize-cx,"0x%02x,",*(arr+i));//5 bytes per byte | |
156 | } | |
157 | cx += snprintf(output+cx,outsize-cx,"};"); | |
158 | prnlog(output); | |
159 | } | |
160 | ||
161 | void printvar(char * name, uint8_t* arr, int len) | |
162 | { | |
163 | int cx; | |
164 | size_t outsize = 40+strlen(name)+len*2; | |
165 | char* output = malloc(outsize); | |
166 | memset(output, 0,outsize); | |
167 | ||
168 | int i ; | |
169 | cx = snprintf(output,outsize,"%s = ", name); | |
170 | for(i =0 ; i< len ; i++) | |
171 | { | |
172 | cx += snprintf(output+cx,outsize-cx,"%02x",*(arr+i));//2 bytes per byte | |
173 | } | |
174 | ||
175 | prnlog(output); | |
176 | } | |
177 | ||
178 | void printarr_human_readable(char * title, uint8_t* arr, int len) | |
179 | { | |
180 | int cx; | |
181 | size_t outsize = 100+strlen(title)+len*4; | |
182 | char* output = malloc(outsize); | |
183 | memset(output, 0,outsize); | |
a66fca86 AD |
184 | |
185 | ||
3ad48540 MHS |
186 | int i; |
187 | cx = snprintf(output,outsize, "\n\t%s\n", title); | |
188 | for(i =0 ; i< len ; i++) | |
189 | { | |
190 | if(i % 16 == 0) | |
191 | cx += snprintf(output+cx,outsize-cx,"\n%02x| ", i ); | |
192 | cx += snprintf(output+cx,outsize-cx, "%02x ",*(arr+i)); | |
193 | } | |
194 | prnlog(output); | |
ca4714cd | 195 | free(output); |
3ad48540 MHS |
196 | } |
197 | ||
a66fca86 AD |
198 | //----------------------------- |
199 | // Code for testing below | |
200 | //----------------------------- | |
201 | ||
202 | ||
203 | int testBitStream() | |
204 | { | |
205 | uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF}; | |
206 | uint8_t output [] = {0,0,0,0,0,0,0,0}; | |
207 | BitstreamIn in = { input, sizeof(input) * 8,0}; | |
208 | BitstreamOut out ={ output, 0,0} | |
209 | ; | |
210 | while(bitsLeft(&in) > 0) | |
211 | { | |
212 | pushBit(&out, headBit(&in)); | |
213 | //printf("Bits left: %d\n", bitsLeft(&in)); | |
214 | //printf("Bits out: %d\n", numBits(&out)); | |
215 | } | |
216 | if(memcmp(input, output, sizeof(input)) == 0) | |
217 | { | |
3ad48540 | 218 | prnlog(" Bitstream test 1 ok"); |
a66fca86 AD |
219 | }else |
220 | { | |
3ad48540 | 221 | prnlog(" Bitstream test 1 failed"); |
a66fca86 AD |
222 | uint8_t i; |
223 | for(i = 0 ; i < sizeof(input) ; i++) | |
224 | { | |
3ad48540 | 225 | prnlog(" IN %02x, OUT %02x", input[i], output[i]); |
a66fca86 AD |
226 | } |
227 | return 1; | |
228 | } | |
229 | return 0; | |
230 | } | |
231 | ||
232 | int testReversedBitstream() | |
233 | { | |
234 | uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF}; | |
235 | uint8_t reverse [] = {0,0,0,0,0,0,0,0}; | |
236 | uint8_t output [] = {0,0,0,0,0,0,0,0}; | |
237 | BitstreamIn in = { input, sizeof(input) * 8,0}; | |
238 | BitstreamOut out ={ output, 0,0}; | |
239 | BitstreamIn reversed_in ={ reverse, sizeof(input)*8,0}; | |
240 | BitstreamOut reversed_out ={ reverse,0 ,0}; | |
241 | ||
242 | while(bitsLeft(&in) > 0) | |
243 | { | |
244 | pushBit(&reversed_out, tailBit(&in)); | |
245 | } | |
246 | while(bitsLeft(&reversed_in) > 0) | |
247 | { | |
248 | pushBit(&out, tailBit(&reversed_in)); | |
249 | } | |
250 | if(memcmp(input, output, sizeof(input)) == 0) | |
251 | { | |
3ad48540 | 252 | prnlog(" Bitstream test 2 ok"); |
a66fca86 AD |
253 | }else |
254 | { | |
3ad48540 | 255 | prnlog(" Bitstream test 2 failed"); |
a66fca86 AD |
256 | uint8_t i; |
257 | for(i = 0 ; i < sizeof(input) ; i++) | |
258 | { | |
3ad48540 | 259 | prnlog(" IN %02x, MIDDLE: %02x, OUT %02x", input[i],reverse[i], output[i]); |
a66fca86 AD |
260 | } |
261 | return 1; | |
262 | } | |
263 | return 0; | |
264 | } | |
265 | ||
266 | ||
267 | int testCipherUtils(void) | |
268 | { | |
3ad48540 | 269 | prnlog("[+] Testing some internals..."); |
a66fca86 AD |
270 | int retval = 0; |
271 | retval |= testBitStream(); | |
272 | retval |= testReversedBitstream(); | |
273 | return retval; | |
274 | } |