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1 //-----------------------------------------------------------------------------
2 // Merlok - June 2011, 2012
3 // Gerhard de Koning Gans - May 2008
4 // Hagen Fritsch - June 2010
5 //
6 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
7 // at your option, any later version. See the LICENSE.txt file for the text of
8 // the license.
9 //-----------------------------------------------------------------------------
10 // Routines to support ISO 14443 type A.
11 //-----------------------------------------------------------------------------
12
13 #include "proxmark3.h"
14 #include "apps.h"
15 #include "util.h"
16 #include "string.h"
17 #include "cmd.h"
18
19 #include "iso14443crc.h"
20 #include "iso14443a.h"
21 #include "crapto1.h"
22 #include "mifareutil.h"
23
24 static uint32_t iso14a_timeout;
25 int rsamples = 0;
26 int tracing = TRUE;
27 uint8_t trigger = 0;
28 // the block number for the ISO14443-4 PCB
29 static uint8_t iso14_pcb_blocknum = 0;
30
31 //
32 // ISO14443 timing:
33 //
34 // minimum time between the start bits of consecutive transfers from reader to tag: 7000 carrier (13.56Mhz) cycles
35 #define REQUEST_GUARD_TIME (7000/16 + 1)
36 // minimum time between last modulation of tag and next start bit from reader to tag: 1172 carrier cycles
37 #define FRAME_DELAY_TIME_PICC_TO_PCD (1172/16 + 1)
38 // bool LastCommandWasRequest = FALSE;
39
40 //
41 // Total delays including SSC-Transfers between ARM and FPGA. These are in carrier clock cycles (1/13,56MHz)
42 //
43 // When the PM acts as reader and is receiving tag data, it takes
44 // 3 ticks delay in the AD converter
45 // 16 ticks until the modulation detector completes and sets curbit
46 // 8 ticks until bit_to_arm is assigned from curbit
47 // 8*16 ticks for the transfer from FPGA to ARM
48 // 4*16 ticks until we measure the time
49 // - 8*16 ticks because we measure the time of the previous transfer
50 #define DELAY_AIR2ARM_AS_READER (3 + 16 + 8 + 8*16 + 4*16 - 8*16)
51
52 // When the PM acts as a reader and is sending, it takes
53 // 4*16 ticks until we can write data to the sending hold register
54 // 8*16 ticks until the SHR is transferred to the Sending Shift Register
55 // 8 ticks until the first transfer starts
56 // 8 ticks later the FPGA samples the data
57 // 1 tick to assign mod_sig_coil
58 #define DELAY_ARM2AIR_AS_READER (4*16 + 8*16 + 8 + 8 + 1)
59
60 // When the PM acts as tag and is receiving it takes
61 // 2 ticks delay in the RF part (for the first falling edge),
62 // 3 ticks for the A/D conversion,
63 // 8 ticks on average until the start of the SSC transfer,
64 // 8 ticks until the SSC samples the first data
65 // 7*16 ticks to complete the transfer from FPGA to ARM
66 // 8 ticks until the next ssp_clk rising edge
67 // 4*16 ticks until we measure the time
68 // - 8*16 ticks because we measure the time of the previous transfer
69 #define DELAY_AIR2ARM_AS_TAG (2 + 3 + 8 + 8 + 7*16 + 8 + 4*16 - 8*16)
70
71 // The FPGA will report its internal sending delay in
72 uint16_t FpgaSendQueueDelay;
73 // the 5 first bits are the number of bits buffered in mod_sig_buf
74 // the last three bits are the remaining ticks/2 after the mod_sig_buf shift
75 #define DELAY_FPGA_QUEUE (FpgaSendQueueDelay<<1)
76
77 // When the PM acts as tag and is sending, it takes
78 // 4*16 ticks until we can write data to the sending hold register
79 // 8*16 ticks until the SHR is transferred to the Sending Shift Register
80 // 8 ticks until the first transfer starts
81 // 8 ticks later the FPGA samples the data
82 // + a varying number of ticks in the FPGA Delay Queue (mod_sig_buf)
83 // + 1 tick to assign mod_sig_coil
84 #define DELAY_ARM2AIR_AS_TAG (4*16 + 8*16 + 8 + 8 + DELAY_FPGA_QUEUE + 1)
85
86 // When the PM acts as sniffer and is receiving tag data, it takes
87 // 3 ticks A/D conversion
88 // 14 ticks to complete the modulation detection
89 // 8 ticks (on average) until the result is stored in to_arm
90 // + the delays in transferring data - which is the same for
91 // sniffing reader and tag data and therefore not relevant
92 #define DELAY_TAG_AIR2ARM_AS_SNIFFER (3 + 14 + 8)
93
94 // When the PM acts as sniffer and is receiving reader data, it takes
95 // 2 ticks delay in analogue RF receiver (for the falling edge of the
96 // start bit, which marks the start of the communication)
97 // 3 ticks A/D conversion
98 // 8 ticks on average until the data is stored in to_arm.
99 // + the delays in transferring data - which is the same for
100 // sniffing reader and tag data and therefore not relevant
101 #define DELAY_READER_AIR2ARM_AS_SNIFFER (2 + 3 + 8)
102
103 //variables used for timing purposes:
104 //these are in ssp_clk cycles:
105 static uint32_t NextTransferTime;
106 static uint32_t LastTimeProxToAirStart;
107 static uint32_t LastProxToAirDuration;
108
109
110
111 // CARD TO READER - manchester
112 // Sequence D: 11110000 modulation with subcarrier during first half
113 // Sequence E: 00001111 modulation with subcarrier during second half
114 // Sequence F: 00000000 no modulation with subcarrier
115 // READER TO CARD - miller
116 // Sequence X: 00001100 drop after half a period
117 // Sequence Y: 00000000 no drop
118 // Sequence Z: 11000000 drop at start
119 #define SEC_D 0xf0
120 #define SEC_E 0x0f
121 #define SEC_F 0x00
122 #define SEC_X 0x0c
123 #define SEC_Y 0x00
124 #define SEC_Z 0xc0
125
126 const uint8_t OddByteParity[256] = {
127 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
128 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
129 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
130 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
131 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
132 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
133 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
134 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
135 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
136 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
137 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
138 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
139 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
140 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
141 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
142 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1
143 };
144
145 void iso14a_set_trigger(bool enable) {
146 trigger = enable;
147 }
148
149 void iso14a_clear_trace() {
150 uint8_t *trace = BigBuf_get_addr();
151 uint16_t max_traceLen = BigBuf_max_traceLen();
152 memset(trace, 0x44, max_traceLen);
153 traceLen = 0;
154 }
155
156 void iso14a_set_tracing(bool enable) {
157 tracing = enable;
158 }
159
160 void iso14a_set_timeout(uint32_t timeout) {
161 iso14a_timeout = timeout;
162 }
163
164 //-----------------------------------------------------------------------------
165 // Generate the parity value for a byte sequence
166 //
167 //-----------------------------------------------------------------------------
168 byte_t oddparity (const byte_t bt)
169 {
170 return OddByteParity[bt];
171 }
172
173 void GetParity(const uint8_t *pbtCmd, uint16_t iLen, uint8_t *par)
174 {
175 uint16_t paritybit_cnt = 0;
176 uint16_t paritybyte_cnt = 0;
177 uint8_t parityBits = 0;
178
179 for (uint16_t i = 0; i < iLen; i++) {
180 // Generate the parity bits
181 parityBits |= ((OddByteParity[pbtCmd[i]]) << (7-paritybit_cnt));
182 if (paritybit_cnt == 7) {
183 par[paritybyte_cnt] = parityBits; // save 8 Bits parity
184 parityBits = 0; // and advance to next Parity Byte
185 paritybyte_cnt++;
186 paritybit_cnt = 0;
187 } else {
188 paritybit_cnt++;
189 }
190 }
191
192 // save remaining parity bits
193 par[paritybyte_cnt] = parityBits;
194
195 }
196
197 void AppendCrc14443a(uint8_t* data, int len)
198 {
199 ComputeCrc14443(CRC_14443_A,data,len,data+len,data+len+1);
200 }
201
202 // The function LogTrace() is also used by the iClass implementation in iClass.c
203 bool RAMFUNC LogTrace(const uint8_t *btBytes, uint16_t iLen, uint32_t timestamp_start, uint32_t timestamp_end, uint8_t *parity, bool readerToTag)
204 {
205 if (!tracing) return FALSE;
206
207 uint8_t *trace = BigBuf_get_addr();
208 uint16_t num_paritybytes = (iLen-1)/8 + 1; // number of valid paritybytes in *parity
209 uint16_t duration = timestamp_end - timestamp_start;
210
211 // Return when trace is full
212 uint16_t max_traceLen = BigBuf_max_traceLen();
213 if (traceLen + sizeof(iLen) + sizeof(timestamp_start) + sizeof(duration) + num_paritybytes + iLen >= max_traceLen) {
214 tracing = FALSE; // don't trace any more
215 return FALSE;
216 }
217
218 // Traceformat:
219 // 32 bits timestamp (little endian)
220 // 16 bits duration (little endian)
221 // 16 bits data length (little endian, Highest Bit used as readerToTag flag)
222 // y Bytes data
223 // x Bytes parity (one byte per 8 bytes data)
224
225 // timestamp (start)
226 trace[traceLen++] = ((timestamp_start >> 0) & 0xff);
227 trace[traceLen++] = ((timestamp_start >> 8) & 0xff);
228 trace[traceLen++] = ((timestamp_start >> 16) & 0xff);
229 trace[traceLen++] = ((timestamp_start >> 24) & 0xff);
230
231 // duration
232 trace[traceLen++] = ((duration >> 0) & 0xff);
233 trace[traceLen++] = ((duration >> 8) & 0xff);
234
235 // data length
236 trace[traceLen++] = ((iLen >> 0) & 0xff);
237 trace[traceLen++] = ((iLen >> 8) & 0xff);
238
239 // readerToTag flag
240 if (!readerToTag) {
241 trace[traceLen - 1] |= 0x80;
242 }
243
244 // data bytes
245 if (btBytes != NULL && iLen != 0) {
246 memcpy(trace + traceLen, btBytes, iLen);
247 }
248 traceLen += iLen;
249
250 // parity bytes
251 if (parity != NULL && iLen != 0) {
252 memcpy(trace + traceLen, parity, num_paritybytes);
253 }
254 traceLen += num_paritybytes;
255
256 return TRUE;
257 }
258
259 //=============================================================================
260 // ISO 14443 Type A - Miller decoder
261 //=============================================================================
262 // Basics:
263 // This decoder is used when the PM3 acts as a tag.
264 // The reader will generate "pauses" by temporarily switching of the field.
265 // At the PM3 antenna we will therefore measure a modulated antenna voltage.
266 // The FPGA does a comparison with a threshold and would deliver e.g.:
267 // ........ 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 1 .......
268 // The Miller decoder needs to identify the following sequences:
269 // 2 (or 3) ticks pause followed by 6 (or 5) ticks unmodulated: pause at beginning - Sequence Z ("start of communication" or a "0")
270 // 8 ticks without a modulation: no pause - Sequence Y (a "0" or "end of communication" or "no information")
271 // 4 ticks unmodulated followed by 2 (or 3) ticks pause: pause in second half - Sequence X (a "1")
272 // Note 1: the bitstream may start at any time. We therefore need to sync.
273 // Note 2: the interpretation of Sequence Y and Z depends on the preceding sequence.
274 //-----------------------------------------------------------------------------
275 static tUart Uart;
276
277 // Lookup-Table to decide if 4 raw bits are a modulation.
278 // We accept two or three consecutive "0" in any position with the rest "1"
279 const bool Mod_Miller_LUT[] = {
280 TRUE, TRUE, FALSE, TRUE, FALSE, FALSE, FALSE, FALSE,
281 TRUE, TRUE, FALSE, FALSE, TRUE, FALSE, FALSE, FALSE
282 };
283 #define IsMillerModulationNibble1(b) (Mod_Miller_LUT[(b & 0x00F0) >> 4])
284 #define IsMillerModulationNibble2(b) (Mod_Miller_LUT[(b & 0x000F)])
285
286 void UartReset()
287 {
288 Uart.state = STATE_UNSYNCD;
289 Uart.bitCount = 0;
290 Uart.len = 0; // number of decoded data bytes
291 Uart.parityLen = 0; // number of decoded parity bytes
292 Uart.shiftReg = 0; // shiftreg to hold decoded data bits
293 Uart.parityBits = 0; // holds 8 parity bits
294 Uart.twoBits = 0x0000; // buffer for 2 Bits
295 Uart.highCnt = 0;
296 Uart.startTime = 0;
297 Uart.endTime = 0;
298 }
299
300 void UartInit(uint8_t *data, uint8_t *parity)
301 {
302 Uart.output = data;
303 Uart.parity = parity;
304 UartReset();
305 }
306
307 // use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time
308 static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
309 {
310
311 Uart.twoBits = (Uart.twoBits << 8) | bit;
312
313 if (Uart.state == STATE_UNSYNCD) { // not yet synced
314
315 if (Uart.highCnt < 7) { // wait for a stable unmodulated signal
316 if (Uart.twoBits == 0xffff) {
317 Uart.highCnt++;
318 } else {
319 Uart.highCnt = 0;
320 }
321 } else {
322 Uart.syncBit = 0xFFFF; // not set
323 // look for 00xx1111 (the start bit)
324 if ((Uart.twoBits & 0x6780) == 0x0780) Uart.syncBit = 7;
325 else if ((Uart.twoBits & 0x33C0) == 0x03C0) Uart.syncBit = 6;
326 else if ((Uart.twoBits & 0x19E0) == 0x01E0) Uart.syncBit = 5;
327 else if ((Uart.twoBits & 0x0CF0) == 0x00F0) Uart.syncBit = 4;
328 else if ((Uart.twoBits & 0x0678) == 0x0078) Uart.syncBit = 3;
329 else if ((Uart.twoBits & 0x033C) == 0x003C) Uart.syncBit = 2;
330 else if ((Uart.twoBits & 0x019E) == 0x001E) Uart.syncBit = 1;
331 else if ((Uart.twoBits & 0x00CF) == 0x000F) Uart.syncBit = 0;
332 if (Uart.syncBit != 0xFFFF) {
333 Uart.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
334 Uart.startTime -= Uart.syncBit;
335 Uart.endTime = Uart.startTime;
336 Uart.state = STATE_START_OF_COMMUNICATION;
337 }
338 }
339
340 } else {
341
342 if (IsMillerModulationNibble1(Uart.twoBits >> Uart.syncBit)) {
343 if (IsMillerModulationNibble2(Uart.twoBits >> Uart.syncBit)) { // Modulation in both halves - error
344 UartReset();
345 Uart.highCnt = 6;
346 } else { // Modulation in first half = Sequence Z = logic "0"
347 if (Uart.state == STATE_MILLER_X) { // error - must not follow after X
348 UartReset();
349 Uart.highCnt = 6;
350 } else {
351 Uart.bitCount++;
352 Uart.shiftReg = (Uart.shiftReg >> 1); // add a 0 to the shiftreg
353 Uart.state = STATE_MILLER_Z;
354 Uart.endTime = Uart.startTime + 8*(9*Uart.len + Uart.bitCount + 1) - 6;
355 if(Uart.bitCount >= 9) { // if we decoded a full byte (including parity)
356 Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
357 Uart.parityBits <<= 1; // make room for the parity bit
358 Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); // store parity bit
359 Uart.bitCount = 0;
360 Uart.shiftReg = 0;
361 if((Uart.len&0x0007) == 0) { // every 8 data bytes
362 Uart.parity[Uart.parityLen++] = Uart.parityBits; // store 8 parity bits
363 Uart.parityBits = 0;
364 }
365 }
366 }
367 }
368 } else {
369 if (IsMillerModulationNibble2(Uart.twoBits >> Uart.syncBit)) { // Modulation second half = Sequence X = logic "1"
370 Uart.bitCount++;
371 Uart.shiftReg = (Uart.shiftReg >> 1) | 0x100; // add a 1 to the shiftreg
372 Uart.state = STATE_MILLER_X;
373 Uart.endTime = Uart.startTime + 8*(9*Uart.len + Uart.bitCount + 1) - 2;
374 if(Uart.bitCount >= 9) { // if we decoded a full byte (including parity)
375 Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
376 Uart.parityBits <<= 1; // make room for the new parity bit
377 Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); // store parity bit
378 Uart.bitCount = 0;
379 Uart.shiftReg = 0;
380 if ((Uart.len&0x0007) == 0) { // every 8 data bytes
381 Uart.parity[Uart.parityLen++] = Uart.parityBits; // store 8 parity bits
382 Uart.parityBits = 0;
383 }
384 }
385 } else { // no modulation in both halves - Sequence Y
386 if (Uart.state == STATE_MILLER_Z || Uart.state == STATE_MILLER_Y) { // Y after logic "0" - End of Communication
387 Uart.state = STATE_UNSYNCD;
388 Uart.bitCount--; // last "0" was part of EOC sequence
389 Uart.shiftReg <<= 1; // drop it
390 if(Uart.bitCount > 0) { // if we decoded some bits
391 Uart.shiftReg >>= (9 - Uart.bitCount); // right align them
392 Uart.output[Uart.len++] = (Uart.shiftReg & 0xff); // add last byte to the output
393 Uart.parityBits <<= 1; // add a (void) parity bit
394 Uart.parityBits <<= (8 - (Uart.len&0x0007)); // left align parity bits
395 Uart.parity[Uart.parityLen++] = Uart.parityBits; // and store it
396 return TRUE;
397 } else if (Uart.len & 0x0007) { // there are some parity bits to store
398 Uart.parityBits <<= (8 - (Uart.len&0x0007)); // left align remaining parity bits
399 Uart.parity[Uart.parityLen++] = Uart.parityBits; // and store them
400 }
401 if (Uart.len) {
402 return TRUE; // we are finished with decoding the raw data sequence
403 } else {
404 UartReset(); // Nothing receiver - start over
405 }
406 }
407 if (Uart.state == STATE_START_OF_COMMUNICATION) { // error - must not follow directly after SOC
408 UartReset();
409 Uart.highCnt = 6;
410 } else { // a logic "0"
411 Uart.bitCount++;
412 Uart.shiftReg = (Uart.shiftReg >> 1); // add a 0 to the shiftreg
413 Uart.state = STATE_MILLER_Y;
414 if(Uart.bitCount >= 9) { // if we decoded a full byte (including parity)
415 Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
416 Uart.parityBits <<= 1; // make room for the parity bit
417 Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); // store parity bit
418 Uart.bitCount = 0;
419 Uart.shiftReg = 0;
420 if ((Uart.len&0x0007) == 0) { // every 8 data bytes
421 Uart.parity[Uart.parityLen++] = Uart.parityBits; // store 8 parity bits
422 Uart.parityBits = 0;
423 }
424 }
425 }
426 }
427 }
428
429 }
430
431 return FALSE; // not finished yet, need more data
432 }
433
434
435
436 //=============================================================================
437 // ISO 14443 Type A - Manchester decoder
438 //=============================================================================
439 // Basics:
440 // This decoder is used when the PM3 acts as a reader.
441 // The tag will modulate the reader field by asserting different loads to it. As a consequence, the voltage
442 // at the reader antenna will be modulated as well. The FPGA detects the modulation for us and would deliver e.g. the following:
443 // ........ 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 .......
444 // The Manchester decoder needs to identify the following sequences:
445 // 4 ticks modulated followed by 4 ticks unmodulated: Sequence D = 1 (also used as "start of communication")
446 // 4 ticks unmodulated followed by 4 ticks modulated: Sequence E = 0
447 // 8 ticks unmodulated: Sequence F = end of communication
448 // 8 ticks modulated: A collision. Save the collision position and treat as Sequence D
449 // Note 1: the bitstream may start at any time. We therefore need to sync.
450 // Note 2: parameter offset is used to determine the position of the parity bits (required for the anticollision command only)
451 static tDemod Demod;
452
453 // Lookup-Table to decide if 4 raw bits are a modulation.
454 // We accept three or four "1" in any position
455 const bool Mod_Manchester_LUT[] = {
456 FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE,
457 FALSE, FALSE, FALSE, TRUE, FALSE, TRUE, TRUE, TRUE
458 };
459
460 #define IsManchesterModulationNibble1(b) (Mod_Manchester_LUT[(b & 0x00F0) >> 4])
461 #define IsManchesterModulationNibble2(b) (Mod_Manchester_LUT[(b & 0x000F)])
462
463
464 void DemodReset()
465 {
466 Demod.state = DEMOD_UNSYNCD;
467 Demod.len = 0; // number of decoded data bytes
468 Demod.parityLen = 0;
469 Demod.shiftReg = 0; // shiftreg to hold decoded data bits
470 Demod.parityBits = 0; //
471 Demod.collisionPos = 0; // Position of collision bit
472 Demod.twoBits = 0xffff; // buffer for 2 Bits
473 Demod.highCnt = 0;
474 Demod.startTime = 0;
475 Demod.endTime = 0;
476 }
477
478 void DemodInit(uint8_t *data, uint8_t *parity)
479 {
480 Demod.output = data;
481 Demod.parity = parity;
482 DemodReset();
483 }
484
485 // use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time
486 static RAMFUNC int ManchesterDecoding(uint8_t bit, uint16_t offset, uint32_t non_real_time)
487 {
488
489 Demod.twoBits = (Demod.twoBits << 8) | bit;
490
491 if (Demod.state == DEMOD_UNSYNCD) {
492
493 if (Demod.highCnt < 2) { // wait for a stable unmodulated signal
494 if (Demod.twoBits == 0x0000) {
495 Demod.highCnt++;
496 } else {
497 Demod.highCnt = 0;
498 }
499 } else {
500 Demod.syncBit = 0xFFFF; // not set
501 if ((Demod.twoBits & 0x7700) == 0x7000) Demod.syncBit = 7;
502 else if ((Demod.twoBits & 0x3B80) == 0x3800) Demod.syncBit = 6;
503 else if ((Demod.twoBits & 0x1DC0) == 0x1C00) Demod.syncBit = 5;
504 else if ((Demod.twoBits & 0x0EE0) == 0x0E00) Demod.syncBit = 4;
505 else if ((Demod.twoBits & 0x0770) == 0x0700) Demod.syncBit = 3;
506 else if ((Demod.twoBits & 0x03B8) == 0x0380) Demod.syncBit = 2;
507 else if ((Demod.twoBits & 0x01DC) == 0x01C0) Demod.syncBit = 1;
508 else if ((Demod.twoBits & 0x00EE) == 0x00E0) Demod.syncBit = 0;
509 if (Demod.syncBit != 0xFFFF) {
510 Demod.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
511 Demod.startTime -= Demod.syncBit;
512 Demod.bitCount = offset; // number of decoded data bits
513 Demod.state = DEMOD_MANCHESTER_DATA;
514 }
515 }
516
517 } else {
518
519 if (IsManchesterModulationNibble1(Demod.twoBits >> Demod.syncBit)) { // modulation in first half
520 if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) { // ... and in second half = collision
521 if (!Demod.collisionPos) {
522 Demod.collisionPos = (Demod.len << 3) + Demod.bitCount;
523 }
524 } // modulation in first half only - Sequence D = 1
525 Demod.bitCount++;
526 Demod.shiftReg = (Demod.shiftReg >> 1) | 0x100; // in both cases, add a 1 to the shiftreg
527 if(Demod.bitCount == 9) { // if we decoded a full byte (including parity)
528 Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
529 Demod.parityBits <<= 1; // make room for the parity bit
530 Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); // store parity bit
531 Demod.bitCount = 0;
532 Demod.shiftReg = 0;
533 if((Demod.len&0x0007) == 0) { // every 8 data bytes
534 Demod.parity[Demod.parityLen++] = Demod.parityBits; // store 8 parity bits
535 Demod.parityBits = 0;
536 }
537 }
538 Demod.endTime = Demod.startTime + 8*(9*Demod.len + Demod.bitCount + 1) - 4;
539 } else { // no modulation in first half
540 if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) { // and modulation in second half = Sequence E = 0
541 Demod.bitCount++;
542 Demod.shiftReg = (Demod.shiftReg >> 1); // add a 0 to the shiftreg
543 if(Demod.bitCount >= 9) { // if we decoded a full byte (including parity)
544 Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
545 Demod.parityBits <<= 1; // make room for the new parity bit
546 Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); // store parity bit
547 Demod.bitCount = 0;
548 Demod.shiftReg = 0;
549 if ((Demod.len&0x0007) == 0) { // every 8 data bytes
550 Demod.parity[Demod.parityLen++] = Demod.parityBits; // store 8 parity bits1
551 Demod.parityBits = 0;
552 }
553 }
554 Demod.endTime = Demod.startTime + 8*(9*Demod.len + Demod.bitCount + 1);
555 } else { // no modulation in both halves - End of communication
556 if(Demod.bitCount > 0) { // there are some remaining data bits
557 Demod.shiftReg >>= (9 - Demod.bitCount); // right align the decoded bits
558 Demod.output[Demod.len++] = Demod.shiftReg & 0xff; // and add them to the output
559 Demod.parityBits <<= 1; // add a (void) parity bit
560 Demod.parityBits <<= (8 - (Demod.len&0x0007)); // left align remaining parity bits
561 Demod.parity[Demod.parityLen++] = Demod.parityBits; // and store them
562 return TRUE;
563 } else if (Demod.len & 0x0007) { // there are some parity bits to store
564 Demod.parityBits <<= (8 - (Demod.len&0x0007)); // left align remaining parity bits
565 Demod.parity[Demod.parityLen++] = Demod.parityBits; // and store them
566 }
567 if (Demod.len) {
568 return TRUE; // we are finished with decoding the raw data sequence
569 } else { // nothing received. Start over
570 DemodReset();
571 }
572 }
573 }
574
575 }
576
577 return FALSE; // not finished yet, need more data
578 }
579
580 //=============================================================================
581 // Finally, a `sniffer' for ISO 14443 Type A
582 // Both sides of communication!
583 //=============================================================================
584
585 //-----------------------------------------------------------------------------
586 // Record the sequence of commands sent by the reader to the tag, with
587 // triggering so that we start recording at the point that the tag is moved
588 // near the reader.
589 //-----------------------------------------------------------------------------
590 void RAMFUNC SnoopIso14443a(uint8_t param) {
591 // param:
592 // bit 0 - trigger from first card answer
593 // bit 1 - trigger from first reader 7-bit request
594
595 LEDsoff();
596
597 // We won't start recording the frames that we acquire until we trigger;
598 // a good trigger condition to get started is probably when we see a
599 // response from the tag.
600 // triggered == FALSE -- to wait first for card
601 bool triggered = !(param & 0x03);
602
603 // Allocate memory from BigBuf for some buffers
604 // free all previous allocations first
605 BigBuf_free();
606
607 // The command (reader -> tag) that we're receiving.
608 uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
609 uint8_t *receivedCmdPar = BigBuf_malloc(MAX_PARITY_SIZE);
610
611 // The response (tag -> reader) that we're receiving.
612 uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
613 uint8_t *receivedResponsePar = BigBuf_malloc(MAX_PARITY_SIZE);
614
615 // The DMA buffer, used to stream samples from the FPGA
616 uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
617
618 // init trace buffer
619 iso14a_clear_trace();
620 iso14a_set_tracing(TRUE);
621
622 uint8_t *data = dmaBuf;
623 uint8_t previous_data = 0;
624 int maxDataLen = 0;
625 int dataLen = 0;
626 bool TagIsActive = FALSE;
627 bool ReaderIsActive = FALSE;
628
629 iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
630
631 // Set up the demodulator for tag -> reader responses.
632 DemodInit(receivedResponse, receivedResponsePar);
633
634 // Set up the demodulator for the reader -> tag commands
635 UartInit(receivedCmd, receivedCmdPar);
636
637 // Setup and start DMA.
638 FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
639
640 // And now we loop, receiving samples.
641 for(uint32_t rsamples = 0; TRUE; ) {
642
643 if(BUTTON_PRESS()) {
644 DbpString("cancelled by button");
645 break;
646 }
647
648 LED_A_ON();
649 WDT_HIT();
650
651 int register readBufDataP = data - dmaBuf;
652 int register dmaBufDataP = DMA_BUFFER_SIZE - AT91C_BASE_PDC_SSC->PDC_RCR;
653 if (readBufDataP <= dmaBufDataP){
654 dataLen = dmaBufDataP - readBufDataP;
655 } else {
656 dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP;
657 }
658 // test for length of buffer
659 if(dataLen > maxDataLen) {
660 maxDataLen = dataLen;
661 if(dataLen > (9 * DMA_BUFFER_SIZE / 10)) {
662 Dbprintf("blew circular buffer! dataLen=%d", dataLen);
663 break;
664 }
665 }
666 if(dataLen < 1) continue;
667
668 // primary buffer was stopped( <-- we lost data!
669 if (!AT91C_BASE_PDC_SSC->PDC_RCR) {
670 AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) dmaBuf;
671 AT91C_BASE_PDC_SSC->PDC_RCR = DMA_BUFFER_SIZE;
672 Dbprintf("RxEmpty ERROR!!! data length:%d", dataLen); // temporary
673 }
674 // secondary buffer sets as primary, secondary buffer was stopped
675 if (!AT91C_BASE_PDC_SSC->PDC_RNCR) {
676 AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
677 AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
678 }
679
680 LED_A_OFF();
681
682 if (rsamples & 0x01) { // Need two samples to feed Miller and Manchester-Decoder
683
684 if(!TagIsActive) { // no need to try decoding reader data if the tag is sending
685 uint8_t readerdata = (previous_data & 0xF0) | (*data >> 4);
686 if (MillerDecoding(readerdata, (rsamples-1)*4)) {
687 LED_C_ON();
688
689 // check - if there is a short 7bit request from reader
690 if ((!triggered) && (param & 0x02) && (Uart.len == 1) && (Uart.bitCount == 7)) triggered = TRUE;
691
692 if(triggered) {
693 if (!LogTrace(receivedCmd,
694 Uart.len,
695 Uart.startTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER,
696 Uart.endTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER,
697 Uart.parity,
698 TRUE)) break;
699 }
700 /* And ready to receive another command. */
701 UartReset();
702 /* And also reset the demod code, which might have been */
703 /* false-triggered by the commands from the reader. */
704 DemodReset();
705 LED_B_OFF();
706 }
707 ReaderIsActive = (Uart.state != STATE_UNSYNCD);
708 }
709
710 if(!ReaderIsActive) { // no need to try decoding tag data if the reader is sending - and we cannot afford the time
711 uint8_t tagdata = (previous_data << 4) | (*data & 0x0F);
712 if(ManchesterDecoding(tagdata, 0, (rsamples-1)*4)) {
713 LED_B_ON();
714
715 if (!LogTrace(receivedResponse,
716 Demod.len,
717 Demod.startTime*16 - DELAY_TAG_AIR2ARM_AS_SNIFFER,
718 Demod.endTime*16 - DELAY_TAG_AIR2ARM_AS_SNIFFER,
719 Demod.parity,
720 FALSE)) break;
721
722 if ((!triggered) && (param & 0x01)) triggered = TRUE;
723
724 // And ready to receive another response.
725 DemodReset();
726 LED_C_OFF();
727 }
728 TagIsActive = (Demod.state != DEMOD_UNSYNCD);
729 }
730 }
731
732 previous_data = *data;
733 rsamples++;
734 data++;
735 if(data == dmaBuf + DMA_BUFFER_SIZE) {
736 data = dmaBuf;
737 }
738 } // main cycle
739
740 DbpString("COMMAND FINISHED");
741
742 FpgaDisableSscDma();
743 Dbprintf("maxDataLen=%d, Uart.state=%x, Uart.len=%d", maxDataLen, Uart.state, Uart.len);
744 Dbprintf("traceLen=%d, Uart.output[0]=%08x", traceLen, (uint32_t)Uart.output[0]);
745 LEDsoff();
746 }
747
748 //-----------------------------------------------------------------------------
749 // Prepare tag messages
750 //-----------------------------------------------------------------------------
751 static void CodeIso14443aAsTagPar(const uint8_t *cmd, uint16_t len, uint8_t *parity)
752 {
753 ToSendReset();
754
755 // Correction bit, might be removed when not needed
756 ToSendStuffBit(0);
757 ToSendStuffBit(0);
758 ToSendStuffBit(0);
759 ToSendStuffBit(0);
760 ToSendStuffBit(1); // 1
761 ToSendStuffBit(0);
762 ToSendStuffBit(0);
763 ToSendStuffBit(0);
764
765 // Send startbit
766 ToSend[++ToSendMax] = SEC_D;
767 LastProxToAirDuration = 8 * ToSendMax - 4;
768
769 for(uint16_t i = 0; i < len; i++) {
770 uint8_t b = cmd[i];
771
772 // Data bits
773 for(uint16_t j = 0; j < 8; j++) {
774 if(b & 1) {
775 ToSend[++ToSendMax] = SEC_D;
776 } else {
777 ToSend[++ToSendMax] = SEC_E;
778 }
779 b >>= 1;
780 }
781
782 // Get the parity bit
783 if (parity[i>>3] & (0x80>>(i&0x0007))) {
784 ToSend[++ToSendMax] = SEC_D;
785 LastProxToAirDuration = 8 * ToSendMax - 4;
786 } else {
787 ToSend[++ToSendMax] = SEC_E;
788 LastProxToAirDuration = 8 * ToSendMax;
789 }
790 }
791
792 // Send stopbit
793 ToSend[++ToSendMax] = SEC_F;
794
795 // Convert from last byte pos to length
796 ToSendMax++;
797 }
798
799 static void CodeIso14443aAsTag(const uint8_t *cmd, uint16_t len)
800 {
801 uint8_t par[MAX_PARITY_SIZE];
802
803 GetParity(cmd, len, par);
804 CodeIso14443aAsTagPar(cmd, len, par);
805 }
806
807
808 static void Code4bitAnswerAsTag(uint8_t cmd)
809 {
810 int i;
811
812 ToSendReset();
813
814 // Correction bit, might be removed when not needed
815 ToSendStuffBit(0);
816 ToSendStuffBit(0);
817 ToSendStuffBit(0);
818 ToSendStuffBit(0);
819 ToSendStuffBit(1); // 1
820 ToSendStuffBit(0);
821 ToSendStuffBit(0);
822 ToSendStuffBit(0);
823
824 // Send startbit
825 ToSend[++ToSendMax] = SEC_D;
826
827 uint8_t b = cmd;
828 for(i = 0; i < 4; i++) {
829 if(b & 1) {
830 ToSend[++ToSendMax] = SEC_D;
831 LastProxToAirDuration = 8 * ToSendMax - 4;
832 } else {
833 ToSend[++ToSendMax] = SEC_E;
834 LastProxToAirDuration = 8 * ToSendMax;
835 }
836 b >>= 1;
837 }
838
839 // Send stopbit
840 ToSend[++ToSendMax] = SEC_F;
841
842 // Convert from last byte pos to length
843 ToSendMax++;
844 }
845
846 //-----------------------------------------------------------------------------
847 // Wait for commands from reader
848 // Stop when button is pressed
849 // Or return TRUE when command is captured
850 //-----------------------------------------------------------------------------
851 static int GetIso14443aCommandFromReader(uint8_t *received, uint8_t *parity, int *len)
852 {
853 // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen
854 // only, since we are receiving, not transmitting).
855 // Signal field is off with the appropriate LED
856 LED_D_OFF();
857 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN);
858
859 // Now run a `software UART' on the stream of incoming samples.
860 UartInit(received, parity);
861
862 // clear RXRDY:
863 uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
864
865 for(;;) {
866 WDT_HIT();
867
868 if(BUTTON_PRESS()) return FALSE;
869
870 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
871 b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
872 if(MillerDecoding(b, 0)) {
873 *len = Uart.len;
874 return TRUE;
875 }
876 }
877 }
878 }
879
880 static int EmSendCmd14443aRaw(uint8_t *resp, uint16_t respLen, bool correctionNeeded);
881 int EmSend4bitEx(uint8_t resp, bool correctionNeeded);
882 int EmSend4bit(uint8_t resp);
883 int EmSendCmdExPar(uint8_t *resp, uint16_t respLen, bool correctionNeeded, uint8_t *par);
884 int EmSendCmdEx(uint8_t *resp, uint16_t respLen, bool correctionNeeded);
885 int EmSendCmd(uint8_t *resp, uint16_t respLen);
886 int EmSendCmdPar(uint8_t *resp, uint16_t respLen, uint8_t *par);
887 bool EmLogTrace(uint8_t *reader_data, uint16_t reader_len, uint32_t reader_StartTime, uint32_t reader_EndTime, uint8_t *reader_Parity,
888 uint8_t *tag_data, uint16_t tag_len, uint32_t tag_StartTime, uint32_t tag_EndTime, uint8_t *tag_Parity);
889
890 static uint8_t* free_buffer_pointer;
891
892 typedef struct {
893 uint8_t* response;
894 size_t response_n;
895 uint8_t* modulation;
896 size_t modulation_n;
897 uint32_t ProxToAirDuration;
898 } tag_response_info_t;
899
900 bool prepare_tag_modulation(tag_response_info_t* response_info, size_t max_buffer_size) {
901 // Example response, answer to MIFARE Classic read block will be 16 bytes + 2 CRC = 18 bytes
902 // This will need the following byte array for a modulation sequence
903 // 144 data bits (18 * 8)
904 // 18 parity bits
905 // 2 Start and stop
906 // 1 Correction bit (Answer in 1172 or 1236 periods, see FPGA)
907 // 1 just for the case
908 // ----------- +
909 // 166 bytes, since every bit that needs to be send costs us a byte
910 //
911
912
913 // Prepare the tag modulation bits from the message
914 CodeIso14443aAsTag(response_info->response,response_info->response_n);
915
916 // Make sure we do not exceed the free buffer space
917 if (ToSendMax > max_buffer_size) {
918 Dbprintf("Out of memory, when modulating bits for tag answer:");
919 Dbhexdump(response_info->response_n,response_info->response,false);
920 return false;
921 }
922
923 // Copy the byte array, used for this modulation to the buffer position
924 memcpy(response_info->modulation,ToSend,ToSendMax);
925
926 // Store the number of bytes that were used for encoding/modulation and the time needed to transfer them
927 response_info->modulation_n = ToSendMax;
928 response_info->ProxToAirDuration = LastProxToAirDuration;
929
930 return true;
931 }
932
933
934 // "precompile" responses. There are 7 predefined responses with a total of 28 bytes data to transmit.
935 // Coded responses need one byte per bit to transfer (data, parity, start, stop, correction)
936 // 28 * 8 data bits, 28 * 1 parity bits, 7 start bits, 7 stop bits, 7 correction bits
937 // -> need 273 bytes buffer
938 #define ALLOCATED_TAG_MODULATION_BUFFER_SIZE 273
939
940 bool prepare_allocated_tag_modulation(tag_response_info_t* response_info) {
941 // Retrieve and store the current buffer index
942 response_info->modulation = free_buffer_pointer;
943
944 // Determine the maximum size we can use from our buffer
945 size_t max_buffer_size = ALLOCATED_TAG_MODULATION_BUFFER_SIZE;
946
947 // Forward the prepare tag modulation function to the inner function
948 if (prepare_tag_modulation(response_info, max_buffer_size)) {
949 // Update the free buffer offset
950 free_buffer_pointer += ToSendMax;
951 return true;
952 } else {
953 return false;
954 }
955 }
956
957 //-----------------------------------------------------------------------------
958 // Main loop of simulated tag: receive commands from reader, decide what
959 // response to send, and send it.
960 //-----------------------------------------------------------------------------
961 void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
962 {
963 uint8_t sak;
964
965 // The first response contains the ATQA (note: bytes are transmitted in reverse order).
966 uint8_t response1[2];
967
968 switch (tagType) {
969 case 1: { // MIFARE Classic
970 // Says: I am Mifare 1k - original line
971 response1[0] = 0x04;
972 response1[1] = 0x00;
973 sak = 0x08;
974 } break;
975 case 2: { // MIFARE Ultralight
976 // Says: I am a stupid memory tag, no crypto
977 response1[0] = 0x04;
978 response1[1] = 0x00;
979 sak = 0x00;
980 } break;
981 case 3: { // MIFARE DESFire
982 // Says: I am a DESFire tag, ph33r me
983 response1[0] = 0x04;
984 response1[1] = 0x03;
985 sak = 0x20;
986 } break;
987 case 4: { // ISO/IEC 14443-4
988 // Says: I am a javacard (JCOP)
989 response1[0] = 0x04;
990 response1[1] = 0x00;
991 sak = 0x28;
992 } break;
993 case 5: { // MIFARE TNP3XXX
994 // Says: I am a toy
995 response1[0] = 0x01;
996 response1[1] = 0x0f;
997 sak = 0x01;
998 } break;
999 default: {
1000 Dbprintf("Error: unkown tagtype (%d)",tagType);
1001 return;
1002 } break;
1003 }
1004
1005 // The second response contains the (mandatory) first 24 bits of the UID
1006 uint8_t response2[5] = {0x00};
1007
1008 // Check if the uid uses the (optional) part
1009 uint8_t response2a[5] = {0x00};
1010
1011 if (uid_2nd) {
1012 response2[0] = 0x88;
1013 num_to_bytes(uid_1st,3,response2+1);
1014 num_to_bytes(uid_2nd,4,response2a);
1015 response2a[4] = response2a[0] ^ response2a[1] ^ response2a[2] ^ response2a[3];
1016
1017 // Configure the ATQA and SAK accordingly
1018 response1[0] |= 0x40;
1019 sak |= 0x04;
1020 } else {
1021 num_to_bytes(uid_1st,4,response2);
1022 // Configure the ATQA and SAK accordingly
1023 response1[0] &= 0xBF;
1024 sak &= 0xFB;
1025 }
1026
1027 // Calculate the BitCountCheck (BCC) for the first 4 bytes of the UID.
1028 response2[4] = response2[0] ^ response2[1] ^ response2[2] ^ response2[3];
1029
1030 // Prepare the mandatory SAK (for 4 and 7 byte UID)
1031 uint8_t response3[3] = {0x00};
1032 response3[0] = sak;
1033 ComputeCrc14443(CRC_14443_A, response3, 1, &response3[1], &response3[2]);
1034
1035 // Prepare the optional second SAK (for 7 byte UID), drop the cascade bit
1036 uint8_t response3a[3] = {0x00};
1037 response3a[0] = sak & 0xFB;
1038 ComputeCrc14443(CRC_14443_A, response3a, 1, &response3a[1], &response3a[2]);
1039
1040 uint8_t response5[] = { 0x00, 0x00, 0x00, 0x00 }; // Very random tag nonce
1041 uint8_t response6[] = { 0x04, 0x58, 0x80, 0x02, 0x00, 0x00 }; // dummy ATS (pseudo-ATR), answer to RATS:
1042 // Format byte = 0x58: FSCI=0x08 (FSC=256), TA(1) and TC(1) present,
1043 // TA(1) = 0x80: different divisors not supported, DR = 1, DS = 1
1044 // TB(1) = not present. Defaults: FWI = 4 (FWT = 256 * 16 * 2^4 * 1/fc = 4833us), SFGI = 0 (SFG = 256 * 16 * 2^0 * 1/fc = 302us)
1045 // TC(1) = 0x02: CID supported, NAD not supported
1046 ComputeCrc14443(CRC_14443_A, response6, 4, &response6[4], &response6[5]);
1047
1048 #define TAG_RESPONSE_COUNT 7
1049 tag_response_info_t responses[TAG_RESPONSE_COUNT] = {
1050 { .response = response1, .response_n = sizeof(response1) }, // Answer to request - respond with card type
1051 { .response = response2, .response_n = sizeof(response2) }, // Anticollision cascade1 - respond with uid
1052 { .response = response2a, .response_n = sizeof(response2a) }, // Anticollision cascade2 - respond with 2nd half of uid if asked
1053 { .response = response3, .response_n = sizeof(response3) }, // Acknowledge select - cascade 1
1054 { .response = response3a, .response_n = sizeof(response3a) }, // Acknowledge select - cascade 2
1055 { .response = response5, .response_n = sizeof(response5) }, // Authentication answer (random nonce)
1056 { .response = response6, .response_n = sizeof(response6) }, // dummy ATS (pseudo-ATR), answer to RATS
1057 };
1058
1059 // Allocate 512 bytes for the dynamic modulation, created when the reader queries for it
1060 // Such a response is less time critical, so we can prepare them on the fly
1061 #define DYNAMIC_RESPONSE_BUFFER_SIZE 64
1062 #define DYNAMIC_MODULATION_BUFFER_SIZE 512
1063 uint8_t dynamic_response_buffer[DYNAMIC_RESPONSE_BUFFER_SIZE];
1064 uint8_t dynamic_modulation_buffer[DYNAMIC_MODULATION_BUFFER_SIZE];
1065 tag_response_info_t dynamic_response_info = {
1066 .response = dynamic_response_buffer,
1067 .response_n = 0,
1068 .modulation = dynamic_modulation_buffer,
1069 .modulation_n = 0
1070 };
1071
1072 BigBuf_free_keep_EM();
1073
1074 // allocate buffers:
1075 uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
1076 uint8_t *receivedCmdPar = BigBuf_malloc(MAX_PARITY_SIZE);
1077 free_buffer_pointer = BigBuf_malloc(ALLOCATED_TAG_MODULATION_BUFFER_SIZE);
1078
1079 // clear trace
1080 iso14a_clear_trace();
1081 iso14a_set_tracing(TRUE);
1082
1083 // Prepare the responses of the anticollision phase
1084 // there will be not enough time to do this at the moment the reader sends it REQA
1085 for (size_t i=0; i<TAG_RESPONSE_COUNT; i++) {
1086 prepare_allocated_tag_modulation(&responses[i]);
1087 }
1088
1089 int len = 0;
1090
1091 // To control where we are in the protocol
1092 int order = 0;
1093 int lastorder;
1094
1095 // Just to allow some checks
1096 int happened = 0;
1097 int happened2 = 0;
1098 int cmdsRecvd = 0;
1099
1100 // We need to listen to the high-frequency, peak-detected path.
1101 iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
1102
1103 cmdsRecvd = 0;
1104 tag_response_info_t* p_response;
1105
1106 LED_A_ON();
1107 for(;;) {
1108 // Clean receive command buffer
1109
1110 if(!GetIso14443aCommandFromReader(receivedCmd, receivedCmdPar, &len)) {
1111 DbpString("Button press");
1112 break;
1113 }
1114
1115 p_response = NULL;
1116
1117 // Okay, look at the command now.
1118 lastorder = order;
1119 if(receivedCmd[0] == 0x26) { // Received a REQUEST
1120 p_response = &responses[0]; order = 1;
1121 } else if(receivedCmd[0] == 0x52) { // Received a WAKEUP
1122 p_response = &responses[0]; order = 6;
1123 } else if(receivedCmd[1] == 0x20 && receivedCmd[0] == 0x93) { // Received request for UID (cascade 1)
1124 p_response = &responses[1]; order = 2;
1125 } else if(receivedCmd[1] == 0x20 && receivedCmd[0] == 0x95) { // Received request for UID (cascade 2)
1126 p_response = &responses[2]; order = 20;
1127 } else if(receivedCmd[1] == 0x70 && receivedCmd[0] == 0x93) { // Received a SELECT (cascade 1)
1128 p_response = &responses[3]; order = 3;
1129 } else if(receivedCmd[1] == 0x70 && receivedCmd[0] == 0x95) { // Received a SELECT (cascade 2)
1130 p_response = &responses[4]; order = 30;
1131 } else if(receivedCmd[0] == 0x30) { // Received a (plain) READ
1132 EmSendCmdEx(data+(4*receivedCmd[1]),16,false);
1133 // Dbprintf("Read request from reader: %x %x",receivedCmd[0],receivedCmd[1]);
1134 // We already responded, do not send anything with the EmSendCmd14443aRaw() that is called below
1135 p_response = NULL;
1136 } else if(receivedCmd[0] == 0x50) { // Received a HALT
1137
1138 if (tracing) {
1139 LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
1140 }
1141 p_response = NULL;
1142 } else if(receivedCmd[0] == 0x60 || receivedCmd[0] == 0x61) { // Received an authentication request
1143 p_response = &responses[5]; order = 7;
1144 } else if(receivedCmd[0] == 0xE0) { // Received a RATS request
1145 if (tagType == 1 || tagType == 2) { // RATS not supported
1146 EmSend4bit(CARD_NACK_NA);
1147 p_response = NULL;
1148 } else {
1149 p_response = &responses[6]; order = 70;
1150 }
1151 } else if (order == 7 && len == 8) { // Received {nr] and {ar} (part of authentication)
1152 if (tracing) {
1153 LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
1154 }
1155 uint32_t nr = bytes_to_num(receivedCmd,4);
1156 uint32_t ar = bytes_to_num(receivedCmd+4,4);
1157 Dbprintf("Auth attempt {nr}{ar}: %08x %08x",nr,ar);
1158 } else {
1159 // Check for ISO 14443A-4 compliant commands, look at left nibble
1160 switch (receivedCmd[0]) {
1161
1162 case 0x0B:
1163 case 0x0A: { // IBlock (command)
1164 dynamic_response_info.response[0] = receivedCmd[0];
1165 dynamic_response_info.response[1] = 0x00;
1166 dynamic_response_info.response[2] = 0x90;
1167 dynamic_response_info.response[3] = 0x00;
1168 dynamic_response_info.response_n = 4;
1169 } break;
1170
1171 case 0x1A:
1172 case 0x1B: { // Chaining command
1173 dynamic_response_info.response[0] = 0xaa | ((receivedCmd[0]) & 1);
1174 dynamic_response_info.response_n = 2;
1175 } break;
1176
1177 case 0xaa:
1178 case 0xbb: {
1179 dynamic_response_info.response[0] = receivedCmd[0] ^ 0x11;
1180 dynamic_response_info.response_n = 2;
1181 } break;
1182
1183 case 0xBA: { //
1184 memcpy(dynamic_response_info.response,"\xAB\x00",2);
1185 dynamic_response_info.response_n = 2;
1186 } break;
1187
1188 case 0xCA:
1189 case 0xC2: { // Readers sends deselect command
1190 memcpy(dynamic_response_info.response,"\xCA\x00",2);
1191 dynamic_response_info.response_n = 2;
1192 } break;
1193
1194 default: {
1195 // Never seen this command before
1196 if (tracing) {
1197 LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
1198 }
1199 Dbprintf("Received unknown command (len=%d):",len);
1200 Dbhexdump(len,receivedCmd,false);
1201 // Do not respond
1202 dynamic_response_info.response_n = 0;
1203 } break;
1204 }
1205
1206 if (dynamic_response_info.response_n > 0) {
1207 // Copy the CID from the reader query
1208 dynamic_response_info.response[1] = receivedCmd[1];
1209
1210 // Add CRC bytes, always used in ISO 14443A-4 compliant cards
1211 AppendCrc14443a(dynamic_response_info.response,dynamic_response_info.response_n);
1212 dynamic_response_info.response_n += 2;
1213
1214 if (prepare_tag_modulation(&dynamic_response_info,DYNAMIC_MODULATION_BUFFER_SIZE) == false) {
1215 Dbprintf("Error preparing tag response");
1216 if (tracing) {
1217 LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
1218 }
1219 break;
1220 }
1221 p_response = &dynamic_response_info;
1222 }
1223 }
1224
1225 // Count number of wakeups received after a halt
1226 if(order == 6 && lastorder == 5) { happened++; }
1227
1228 // Count number of other messages after a halt
1229 if(order != 6 && lastorder == 5) { happened2++; }
1230
1231 if(cmdsRecvd > 999) {
1232 DbpString("1000 commands later...");
1233 break;
1234 }
1235 cmdsRecvd++;
1236
1237 if (p_response != NULL) {
1238 EmSendCmd14443aRaw(p_response->modulation, p_response->modulation_n, receivedCmd[0] == 0x52);
1239 // do the tracing for the previous reader request and this tag answer:
1240 uint8_t par[MAX_PARITY_SIZE];
1241 GetParity(p_response->response, p_response->response_n, par);
1242
1243 EmLogTrace(Uart.output,
1244 Uart.len,
1245 Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG,
1246 Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG,
1247 Uart.parity,
1248 p_response->response,
1249 p_response->response_n,
1250 LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG,
1251 (LastTimeProxToAirStart + p_response->ProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG,
1252 par);
1253 }
1254
1255 if (!tracing) {
1256 Dbprintf("Trace Full. Simulation stopped.");
1257 break;
1258 }
1259 }
1260
1261 Dbprintf("%x %x %x", happened, happened2, cmdsRecvd);
1262 LED_A_OFF();
1263 BigBuf_free_keep_EM();
1264 }
1265
1266
1267 // prepare a delayed transfer. This simply shifts ToSend[] by a number
1268 // of bits specified in the delay parameter.
1269 void PrepareDelayedTransfer(uint16_t delay)
1270 {
1271 uint8_t bitmask = 0;
1272 uint8_t bits_to_shift = 0;
1273 uint8_t bits_shifted = 0;
1274
1275 delay &= 0x07;
1276 if (delay) {
1277 for (uint16_t i = 0; i < delay; i++) {
1278 bitmask |= (0x01 << i);
1279 }
1280 ToSend[ToSendMax++] = 0x00;
1281 for (uint16_t i = 0; i < ToSendMax; i++) {
1282 bits_to_shift = ToSend[i] & bitmask;
1283 ToSend[i] = ToSend[i] >> delay;
1284 ToSend[i] = ToSend[i] | (bits_shifted << (8 - delay));
1285 bits_shifted = bits_to_shift;
1286 }
1287 }
1288 }
1289
1290
1291 //-------------------------------------------------------------------------------------
1292 // Transmit the command (to the tag) that was placed in ToSend[].
1293 // Parameter timing:
1294 // if NULL: transfer at next possible time, taking into account
1295 // request guard time and frame delay time
1296 // if == 0: transfer immediately and return time of transfer
1297 // if != 0: delay transfer until time specified
1298 //-------------------------------------------------------------------------------------
1299 static void TransmitFor14443a(const uint8_t *cmd, uint16_t len, uint32_t *timing)
1300 {
1301
1302 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
1303
1304 uint32_t ThisTransferTime = 0;
1305
1306 if (timing) {
1307 if(*timing == 0) { // Measure time
1308 *timing = (GetCountSspClk() + 8) & 0xfffffff8;
1309 } else {
1310 PrepareDelayedTransfer(*timing & 0x00000007); // Delay transfer (fine tuning - up to 7 MF clock ticks)
1311 }
1312 if(MF_DBGLEVEL >= 4 && GetCountSspClk() >= (*timing & 0xfffffff8)) Dbprintf("TransmitFor14443a: Missed timing");
1313 while(GetCountSspClk() < (*timing & 0xfffffff8)); // Delay transfer (multiple of 8 MF clock ticks)
1314 LastTimeProxToAirStart = *timing;
1315 } else {
1316 ThisTransferTime = ((MAX(NextTransferTime, GetCountSspClk()) & 0xfffffff8) + 8);
1317 while(GetCountSspClk() < ThisTransferTime);
1318 LastTimeProxToAirStart = ThisTransferTime;
1319 }
1320
1321 // clear TXRDY
1322 AT91C_BASE_SSC->SSC_THR = SEC_Y;
1323
1324 uint16_t c = 0;
1325 for(;;) {
1326 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1327 AT91C_BASE_SSC->SSC_THR = cmd[c];
1328 c++;
1329 if(c >= len) {
1330 break;
1331 }
1332 }
1333 }
1334
1335 NextTransferTime = MAX(NextTransferTime, LastTimeProxToAirStart + REQUEST_GUARD_TIME);
1336 }
1337
1338
1339 //-----------------------------------------------------------------------------
1340 // Prepare reader command (in bits, support short frames) to send to FPGA
1341 //-----------------------------------------------------------------------------
1342 void CodeIso14443aBitsAsReaderPar(const uint8_t *cmd, uint16_t bits, const uint8_t *parity)
1343 {
1344 int i, j;
1345 int last;
1346 uint8_t b;
1347
1348 ToSendReset();
1349
1350 // Start of Communication (Seq. Z)
1351 ToSend[++ToSendMax] = SEC_Z;
1352 LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
1353 last = 0;
1354
1355 size_t bytecount = nbytes(bits);
1356 // Generate send structure for the data bits
1357 for (i = 0; i < bytecount; i++) {
1358 // Get the current byte to send
1359 b = cmd[i];
1360 size_t bitsleft = MIN((bits-(i*8)),8);
1361
1362 for (j = 0; j < bitsleft; j++) {
1363 if (b & 1) {
1364 // Sequence X
1365 ToSend[++ToSendMax] = SEC_X;
1366 LastProxToAirDuration = 8 * (ToSendMax+1) - 2;
1367 last = 1;
1368 } else {
1369 if (last == 0) {
1370 // Sequence Z
1371 ToSend[++ToSendMax] = SEC_Z;
1372 LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
1373 } else {
1374 // Sequence Y
1375 ToSend[++ToSendMax] = SEC_Y;
1376 last = 0;
1377 }
1378 }
1379 b >>= 1;
1380 }
1381
1382 // Only transmit parity bit if we transmitted a complete byte
1383 if (j == 8) {
1384 // Get the parity bit
1385 if (parity[i>>3] & (0x80 >> (i&0x0007))) {
1386 // Sequence X
1387 ToSend[++ToSendMax] = SEC_X;
1388 LastProxToAirDuration = 8 * (ToSendMax+1) - 2;
1389 last = 1;
1390 } else {
1391 if (last == 0) {
1392 // Sequence Z
1393 ToSend[++ToSendMax] = SEC_Z;
1394 LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
1395 } else {
1396 // Sequence Y
1397 ToSend[++ToSendMax] = SEC_Y;
1398 last = 0;
1399 }
1400 }
1401 }
1402 }
1403
1404 // End of Communication: Logic 0 followed by Sequence Y
1405 if (last == 0) {
1406 // Sequence Z
1407 ToSend[++ToSendMax] = SEC_Z;
1408 LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
1409 } else {
1410 // Sequence Y
1411 ToSend[++ToSendMax] = SEC_Y;
1412 last = 0;
1413 }
1414 ToSend[++ToSendMax] = SEC_Y;
1415
1416 // Convert to length of command:
1417 ToSendMax++;
1418 }
1419
1420 //-----------------------------------------------------------------------------
1421 // Prepare reader command to send to FPGA
1422 //-----------------------------------------------------------------------------
1423 void CodeIso14443aAsReaderPar(const uint8_t *cmd, uint16_t len, const uint8_t *parity)
1424 {
1425 CodeIso14443aBitsAsReaderPar(cmd, len*8, parity);
1426 }
1427
1428 //-----------------------------------------------------------------------------
1429 // Wait for commands from reader
1430 // Stop when button is pressed (return 1) or field was gone (return 2)
1431 // Or return 0 when command is captured
1432 //-----------------------------------------------------------------------------
1433 static int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *parity)
1434 {
1435 *len = 0;
1436
1437 uint32_t timer = 0, vtime = 0;
1438 int analogCnt = 0;
1439 int analogAVG = 0;
1440
1441 // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen
1442 // only, since we are receiving, not transmitting).
1443 // Signal field is off with the appropriate LED
1444 LED_D_OFF();
1445 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN);
1446
1447 // Set ADC to read field strength
1448 AT91C_BASE_ADC->ADC_CR = AT91C_ADC_SWRST;
1449 AT91C_BASE_ADC->ADC_MR =
1450 ADC_MODE_PRESCALE(32) |
1451 ADC_MODE_STARTUP_TIME(16) |
1452 ADC_MODE_SAMPLE_HOLD_TIME(8);
1453 AT91C_BASE_ADC->ADC_CHER = ADC_CHANNEL(ADC_CHAN_HF);
1454 // start ADC
1455 AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
1456
1457 // Now run a 'software UART' on the stream of incoming samples.
1458 UartInit(received, parity);
1459
1460 // Clear RXRDY:
1461 uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1462
1463 for(;;) {
1464 WDT_HIT();
1465
1466 if (BUTTON_PRESS()) return 1;
1467
1468 // test if the field exists
1469 if (AT91C_BASE_ADC->ADC_SR & ADC_END_OF_CONVERSION(ADC_CHAN_HF)) {
1470 analogCnt++;
1471 analogAVG += AT91C_BASE_ADC->ADC_CDR[ADC_CHAN_HF];
1472 AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
1473 if (analogCnt >= 32) {
1474 if ((33000 * (analogAVG / analogCnt) >> 10) < MF_MINFIELDV) {
1475 vtime = GetTickCount();
1476 if (!timer) timer = vtime;
1477 // 50ms no field --> card to idle state
1478 if (vtime - timer > 50) return 2;
1479 } else
1480 if (timer) timer = 0;
1481 analogCnt = 0;
1482 analogAVG = 0;
1483 }
1484 }
1485
1486 // receive and test the miller decoding
1487 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
1488 b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1489 if(MillerDecoding(b, 0)) {
1490 *len = Uart.len;
1491 return 0;
1492 }
1493 }
1494
1495 }
1496 }
1497
1498
1499 static int EmSendCmd14443aRaw(uint8_t *resp, uint16_t respLen, bool correctionNeeded)
1500 {
1501 uint8_t b;
1502 uint16_t i = 0;
1503 uint32_t ThisTransferTime;
1504
1505 // Modulate Manchester
1506 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_MOD);
1507
1508 // include correction bit if necessary
1509 if (Uart.parityBits & 0x01) {
1510 correctionNeeded = TRUE;
1511 }
1512 if(correctionNeeded) {
1513 // 1236, so correction bit needed
1514 i = 0;
1515 } else {
1516 i = 1;
1517 }
1518
1519 // clear receiving shift register and holding register
1520 while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
1521 b = AT91C_BASE_SSC->SSC_RHR; (void) b;
1522 while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
1523 b = AT91C_BASE_SSC->SSC_RHR; (void) b;
1524
1525 // wait for the FPGA to signal fdt_indicator == 1 (the FPGA is ready to queue new data in its delay line)
1526 for (uint16_t j = 0; j < 5; j++) { // allow timeout - better late than never
1527 while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
1528 if (AT91C_BASE_SSC->SSC_RHR) break;
1529 }
1530
1531 while ((ThisTransferTime = GetCountSspClk()) & 0x00000007);
1532
1533 // Clear TXRDY:
1534 AT91C_BASE_SSC->SSC_THR = SEC_F;
1535
1536 // send cycle
1537 for(; i < respLen; ) {
1538 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1539 AT91C_BASE_SSC->SSC_THR = resp[i++];
1540 FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1541 }
1542
1543 if(BUTTON_PRESS()) {
1544 break;
1545 }
1546 }
1547
1548 // Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again:
1549 for (i = 0; i < 2 ; ) {
1550 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1551 AT91C_BASE_SSC->SSC_THR = SEC_F;
1552 FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1553 i++;
1554 }
1555 }
1556
1557 LastTimeProxToAirStart = ThisTransferTime + (correctionNeeded?8:0);
1558
1559 return 0;
1560 }
1561
1562 int EmSend4bitEx(uint8_t resp, bool correctionNeeded){
1563 Code4bitAnswerAsTag(resp);
1564 int res = EmSendCmd14443aRaw(ToSend, ToSendMax, correctionNeeded);
1565 // do the tracing for the previous reader request and this tag answer:
1566 uint8_t par[1];
1567 GetParity(&resp, 1, par);
1568 EmLogTrace(Uart.output,
1569 Uart.len,
1570 Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG,
1571 Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG,
1572 Uart.parity,
1573 &resp,
1574 1,
1575 LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG,
1576 (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG,
1577 par);
1578 return res;
1579 }
1580
1581 int EmSend4bit(uint8_t resp){
1582 return EmSend4bitEx(resp, false);
1583 }
1584
1585 int EmSendCmdExPar(uint8_t *resp, uint16_t respLen, bool correctionNeeded, uint8_t *par){
1586 CodeIso14443aAsTagPar(resp, respLen, par);
1587 int res = EmSendCmd14443aRaw(ToSend, ToSendMax, correctionNeeded);
1588 // do the tracing for the previous reader request and this tag answer:
1589 EmLogTrace(Uart.output,
1590 Uart.len,
1591 Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG,
1592 Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG,
1593 Uart.parity,
1594 resp,
1595 respLen,
1596 LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG,
1597 (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG,
1598 par);
1599 return res;
1600 }
1601
1602 int EmSendCmdEx(uint8_t *resp, uint16_t respLen, bool correctionNeeded){
1603 uint8_t par[MAX_PARITY_SIZE];
1604 GetParity(resp, respLen, par);
1605 return EmSendCmdExPar(resp, respLen, correctionNeeded, par);
1606 }
1607
1608 int EmSendCmd(uint8_t *resp, uint16_t respLen){
1609 uint8_t par[MAX_PARITY_SIZE];
1610 GetParity(resp, respLen, par);
1611 return EmSendCmdExPar(resp, respLen, false, par);
1612 }
1613
1614 int EmSendCmdPar(uint8_t *resp, uint16_t respLen, uint8_t *par){
1615 return EmSendCmdExPar(resp, respLen, false, par);
1616 }
1617
1618 bool EmLogTrace(uint8_t *reader_data, uint16_t reader_len, uint32_t reader_StartTime, uint32_t reader_EndTime, uint8_t *reader_Parity,
1619 uint8_t *tag_data, uint16_t tag_len, uint32_t tag_StartTime, uint32_t tag_EndTime, uint8_t *tag_Parity)
1620 {
1621 if (tracing) {
1622 // we cannot exactly measure the end and start of a received command from reader. However we know that the delay from
1623 // end of the received command to start of the tag's (simulated by us) answer is n*128+20 or n*128+84 resp.
1624 // with n >= 9. The start of the tags answer can be measured and therefore the end of the received command be calculated:
1625 uint16_t reader_modlen = reader_EndTime - reader_StartTime;
1626 uint16_t approx_fdt = tag_StartTime - reader_EndTime;
1627 uint16_t exact_fdt = (approx_fdt - 20 + 32)/64 * 64 + 20;
1628 reader_EndTime = tag_StartTime - exact_fdt;
1629 reader_StartTime = reader_EndTime - reader_modlen;
1630 if (!LogTrace(reader_data, reader_len, reader_StartTime, reader_EndTime, reader_Parity, TRUE)) {
1631 return FALSE;
1632 } else return(!LogTrace(tag_data, tag_len, tag_StartTime, tag_EndTime, tag_Parity, FALSE));
1633 } else {
1634 return TRUE;
1635 }
1636 }
1637
1638 //-----------------------------------------------------------------------------
1639 // Wait a certain time for tag response
1640 // If a response is captured return TRUE
1641 // If it takes too long return FALSE
1642 //-----------------------------------------------------------------------------
1643 static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint8_t *receivedResponsePar, uint16_t offset)
1644 {
1645 uint32_t c;
1646
1647 // Set FPGA mode to "reader listen mode", no modulation (listen
1648 // only, since we are receiving, not transmitting).
1649 // Signal field is on with the appropriate LED
1650 LED_D_ON();
1651 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_LISTEN);
1652
1653 // Now get the answer from the card
1654 DemodInit(receivedResponse, receivedResponsePar);
1655
1656 // clear RXRDY:
1657 uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1658
1659 c = 0;
1660 for(;;) {
1661 WDT_HIT();
1662
1663 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
1664 b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1665 if(ManchesterDecoding(b, offset, 0)) {
1666 NextTransferTime = MAX(NextTransferTime, Demod.endTime - (DELAY_AIR2ARM_AS_READER + DELAY_ARM2AIR_AS_READER)/16 + FRAME_DELAY_TIME_PICC_TO_PCD);
1667 return TRUE;
1668 } else if (c++ > iso14a_timeout) {
1669 return FALSE;
1670 }
1671 }
1672 }
1673 }
1674
1675 void ReaderTransmitBitsPar(uint8_t* frame, uint16_t bits, uint8_t *par, uint32_t *timing)
1676 {
1677 CodeIso14443aBitsAsReaderPar(frame, bits, par);
1678
1679 // Send command to tag
1680 TransmitFor14443a(ToSend, ToSendMax, timing);
1681 if(trigger)
1682 LED_A_ON();
1683
1684 // Log reader command in trace buffer
1685 if (tracing) {
1686 LogTrace(frame, nbytes(bits), LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_READER, (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_READER, par, TRUE);
1687 }
1688 }
1689
1690 void ReaderTransmitPar(uint8_t* frame, uint16_t len, uint8_t *par, uint32_t *timing)
1691 {
1692 ReaderTransmitBitsPar(frame, len*8, par, timing);
1693 }
1694
1695 void ReaderTransmitBits(uint8_t* frame, uint16_t len, uint32_t *timing)
1696 {
1697 // Generate parity and redirect
1698 uint8_t par[MAX_PARITY_SIZE];
1699 GetParity(frame, len/8, par);
1700 ReaderTransmitBitsPar(frame, len, par, timing);
1701 }
1702
1703 void ReaderTransmit(uint8_t* frame, uint16_t len, uint32_t *timing)
1704 {
1705 // Generate parity and redirect
1706 uint8_t par[MAX_PARITY_SIZE];
1707 GetParity(frame, len, par);
1708 ReaderTransmitBitsPar(frame, len*8, par, timing);
1709 }
1710
1711 int ReaderReceiveOffset(uint8_t* receivedAnswer, uint16_t offset, uint8_t *parity)
1712 {
1713 if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, offset)) return FALSE;
1714 if (tracing) {
1715 LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, FALSE);
1716 }
1717 return Demod.len;
1718 }
1719
1720 int ReaderReceive(uint8_t *receivedAnswer, uint8_t *parity)
1721 {
1722 if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, 0)) return FALSE;
1723 if (tracing) {
1724 LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, FALSE);
1725 }
1726 return Demod.len;
1727 }
1728
1729 /* performs iso14443a anticollision procedure
1730 * fills the uid pointer unless NULL
1731 * fills resp_data unless NULL */
1732 int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, uint32_t *cuid_ptr) {
1733 uint8_t wupa[] = { 0x52 }; // 0x26 - REQA 0x52 - WAKE-UP
1734 uint8_t sel_all[] = { 0x93,0x20 };
1735 uint8_t sel_uid[] = { 0x93,0x70,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
1736 uint8_t rats[] = { 0xE0,0x80,0x00,0x00 }; // FSD=256, FSDI=8, CID=0
1737 uint8_t resp[MAX_FRAME_SIZE]; // theoretically. A usual RATS will be much smaller
1738 uint8_t resp_par[MAX_PARITY_SIZE];
1739 byte_t uid_resp[4];
1740 size_t uid_resp_len;
1741
1742 uint8_t sak = 0x04; // cascade uid
1743 int cascade_level = 0;
1744 int len;
1745
1746 // Broadcast for a card, WUPA (0x52) will force response from all cards in the field
1747 ReaderTransmitBitsPar(wupa,7,0, NULL);
1748
1749 // Receive the ATQA
1750 if(!ReaderReceive(resp, resp_par)) return 0;
1751
1752 if(p_hi14a_card) {
1753 memcpy(p_hi14a_card->atqa, resp, 2);
1754 p_hi14a_card->uidlen = 0;
1755 memset(p_hi14a_card->uid,0,10);
1756 }
1757
1758 // clear uid
1759 if (uid_ptr) {
1760 memset(uid_ptr,0,10);
1761 }
1762
1763 // OK we will select at least at cascade 1, lets see if first byte of UID was 0x88 in
1764 // which case we need to make a cascade 2 request and select - this is a long UID
1765 // While the UID is not complete, the 3nd bit (from the right) is set in the SAK.
1766 for(; sak & 0x04; cascade_level++) {
1767 // SELECT_* (L1: 0x93, L2: 0x95, L3: 0x97)
1768 sel_uid[0] = sel_all[0] = 0x93 + cascade_level * 2;
1769
1770 // SELECT_ALL
1771 ReaderTransmit(sel_all, sizeof(sel_all), NULL);
1772 if (!ReaderReceive(resp, resp_par)) return 0;
1773
1774 if (Demod.collisionPos) { // we had a collision and need to construct the UID bit by bit
1775 memset(uid_resp, 0, 4);
1776 uint16_t uid_resp_bits = 0;
1777 uint16_t collision_answer_offset = 0;
1778 // anti-collision-loop:
1779 while (Demod.collisionPos) {
1780 Dbprintf("Multiple tags detected. Collision after Bit %d", Demod.collisionPos);
1781 for (uint16_t i = collision_answer_offset; i < Demod.collisionPos; i++, uid_resp_bits++) { // add valid UID bits before collision point
1782 uint16_t UIDbit = (resp[i/8] >> (i % 8)) & 0x01;
1783 uid_resp[uid_resp_bits / 8] |= UIDbit << (uid_resp_bits % 8);
1784 }
1785 uid_resp[uid_resp_bits/8] |= 1 << (uid_resp_bits % 8); // next time select the card(s) with a 1 in the collision position
1786 uid_resp_bits++;
1787 // construct anticollosion command:
1788 sel_uid[1] = ((2 + uid_resp_bits/8) << 4) | (uid_resp_bits & 0x07); // length of data in bytes and bits
1789 for (uint16_t i = 0; i <= uid_resp_bits/8; i++) {
1790 sel_uid[2+i] = uid_resp[i];
1791 }
1792 collision_answer_offset = uid_resp_bits%8;
1793 ReaderTransmitBits(sel_uid, 16 + uid_resp_bits, NULL);
1794 if (!ReaderReceiveOffset(resp, collision_answer_offset, resp_par)) return 0;
1795 }
1796 // finally, add the last bits and BCC of the UID
1797 for (uint16_t i = collision_answer_offset; i < (Demod.len-1)*8; i++, uid_resp_bits++) {
1798 uint16_t UIDbit = (resp[i/8] >> (i%8)) & 0x01;
1799 uid_resp[uid_resp_bits/8] |= UIDbit << (uid_resp_bits % 8);
1800 }
1801
1802 } else { // no collision, use the response to SELECT_ALL as current uid
1803 memcpy(uid_resp, resp, 4);
1804 }
1805 uid_resp_len = 4;
1806
1807 // calculate crypto UID. Always use last 4 Bytes.
1808 if(cuid_ptr) {
1809 *cuid_ptr = bytes_to_num(uid_resp, 4);
1810 }
1811
1812 // Construct SELECT UID command
1813 sel_uid[1] = 0x70; // transmitting a full UID (1 Byte cmd, 1 Byte NVB, 4 Byte UID, 1 Byte BCC, 2 Bytes CRC)
1814 memcpy(sel_uid+2, uid_resp, 4); // the UID
1815 sel_uid[6] = sel_uid[2] ^ sel_uid[3] ^ sel_uid[4] ^ sel_uid[5]; // calculate and add BCC
1816 AppendCrc14443a(sel_uid, 7); // calculate and add CRC
1817 ReaderTransmit(sel_uid, sizeof(sel_uid), NULL);
1818
1819 // Receive the SAK
1820 if (!ReaderReceive(resp, resp_par)) return 0;
1821 sak = resp[0];
1822
1823 // Test if more parts of the uid are coming
1824 if ((sak & 0x04) /* && uid_resp[0] == 0x88 */) {
1825 // Remove first byte, 0x88 is not an UID byte, it CT, see page 3 of:
1826 // http://www.nxp.com/documents/application_note/AN10927.pdf
1827 uid_resp[0] = uid_resp[1];
1828 uid_resp[1] = uid_resp[2];
1829 uid_resp[2] = uid_resp[3];
1830
1831 uid_resp_len = 3;
1832 }
1833
1834 if(uid_ptr) {
1835 memcpy(uid_ptr + (cascade_level*3), uid_resp, uid_resp_len);
1836 }
1837
1838 if(p_hi14a_card) {
1839 memcpy(p_hi14a_card->uid + (cascade_level*3), uid_resp, uid_resp_len);
1840 p_hi14a_card->uidlen += uid_resp_len;
1841 }
1842 }
1843
1844 if(p_hi14a_card) {
1845 p_hi14a_card->sak = sak;
1846 p_hi14a_card->ats_len = 0;
1847 }
1848
1849 // non iso14443a compliant tag
1850 if( (sak & 0x20) == 0) return 2;
1851
1852 // Request for answer to select
1853 AppendCrc14443a(rats, 2);
1854 ReaderTransmit(rats, sizeof(rats), NULL);
1855
1856 if (!(len = ReaderReceive(resp, resp_par))) return 0;
1857
1858
1859 if(p_hi14a_card) {
1860 memcpy(p_hi14a_card->ats, resp, sizeof(p_hi14a_card->ats));
1861 p_hi14a_card->ats_len = len;
1862 }
1863
1864 // reset the PCB block number
1865 iso14_pcb_blocknum = 0;
1866 return 1;
1867 }
1868
1869 void iso14443a_setup(uint8_t fpga_minor_mode) {
1870 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
1871 // Set up the synchronous serial port
1872 FpgaSetupSsc();
1873 // connect Demodulated Signal to ADC:
1874 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
1875
1876 // Signal field is on with the appropriate LED
1877 if (fpga_minor_mode == FPGA_HF_ISO14443A_READER_MOD
1878 || fpga_minor_mode == FPGA_HF_ISO14443A_READER_LISTEN) {
1879 LED_D_ON();
1880 } else {
1881 LED_D_OFF();
1882 }
1883 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | fpga_minor_mode);
1884
1885 // Start the timer
1886 StartCountSspClk();
1887
1888 DemodReset();
1889 UartReset();
1890 NextTransferTime = 2*DELAY_ARM2AIR_AS_READER;
1891 iso14a_set_timeout(1050); // 10ms default
1892 }
1893
1894 int iso14_apdu(uint8_t *cmd, uint16_t cmd_len, void *data) {
1895 uint8_t parity[MAX_PARITY_SIZE];
1896 uint8_t real_cmd[cmd_len+4];
1897 real_cmd[0] = 0x0a; //I-Block
1898 // put block number into the PCB
1899 real_cmd[0] |= iso14_pcb_blocknum;
1900 real_cmd[1] = 0x00; //CID: 0 //FIXME: allow multiple selected cards
1901 memcpy(real_cmd+2, cmd, cmd_len);
1902 AppendCrc14443a(real_cmd,cmd_len+2);
1903
1904 ReaderTransmit(real_cmd, cmd_len+4, NULL);
1905 size_t len = ReaderReceive(data, parity);
1906 uint8_t *data_bytes = (uint8_t *) data;
1907 if (!len)
1908 return 0; //DATA LINK ERROR
1909 // if we received an I- or R(ACK)-Block with a block number equal to the
1910 // current block number, toggle the current block number
1911 else if (len >= 4 // PCB+CID+CRC = 4 bytes
1912 && ((data_bytes[0] & 0xC0) == 0 // I-Block
1913 || (data_bytes[0] & 0xD0) == 0x80) // R-Block with ACK bit set to 0
1914 && (data_bytes[0] & 0x01) == iso14_pcb_blocknum) // equal block numbers
1915 {
1916 iso14_pcb_blocknum ^= 1;
1917 }
1918
1919 return len;
1920 }
1921
1922 //-----------------------------------------------------------------------------
1923 // Read an ISO 14443a tag. Send out commands and store answers.
1924 //
1925 //-----------------------------------------------------------------------------
1926 void ReaderIso14443a(UsbCommand *c)
1927 {
1928 iso14a_command_t param = c->arg[0];
1929 uint8_t *cmd = c->d.asBytes;
1930 size_t len = c->arg[1];
1931 size_t lenbits = c->arg[2];
1932 uint32_t arg0 = 0;
1933 byte_t buf[USB_CMD_DATA_SIZE];
1934 uint8_t par[MAX_PARITY_SIZE];
1935
1936 if(param & ISO14A_CONNECT) {
1937 iso14a_clear_trace();
1938 }
1939
1940 iso14a_set_tracing(TRUE);
1941
1942 if(param & ISO14A_REQUEST_TRIGGER) {
1943 iso14a_set_trigger(TRUE);
1944 }
1945
1946 if(param & ISO14A_CONNECT) {
1947 iso14443a_setup(FPGA_HF_ISO14443A_READER_LISTEN);
1948 if(!(param & ISO14A_NO_SELECT)) {
1949 iso14a_card_select_t *card = (iso14a_card_select_t*)buf;
1950 arg0 = iso14443a_select_card(NULL,card,NULL);
1951 cmd_send(CMD_ACK,arg0,card->uidlen,0,buf,sizeof(iso14a_card_select_t));
1952 }
1953 }
1954
1955 if(param & ISO14A_SET_TIMEOUT) {
1956 iso14a_set_timeout(c->arg[2]);
1957 }
1958
1959 if(param & ISO14A_APDU) {
1960 arg0 = iso14_apdu(cmd, len, buf);
1961 cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(buf));
1962 }
1963
1964 if(param & ISO14A_RAW) {
1965 if(param & ISO14A_APPEND_CRC) {
1966 AppendCrc14443a(cmd,len);
1967 len += 2;
1968 if (lenbits) lenbits += 16;
1969 }
1970 if(lenbits>0) {
1971 GetParity(cmd, lenbits/8, par);
1972 ReaderTransmitBitsPar(cmd, lenbits, par, NULL);
1973 } else {
1974 ReaderTransmit(cmd,len, NULL);
1975 }
1976 arg0 = ReaderReceive(buf, par);
1977 cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(buf));
1978 }
1979
1980 if(param & ISO14A_REQUEST_TRIGGER) {
1981 iso14a_set_trigger(FALSE);
1982 }
1983
1984 if(param & ISO14A_NO_DISCONNECT) {
1985 return;
1986 }
1987
1988 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
1989 LEDsoff();
1990 }
1991
1992
1993 // Determine the distance between two nonces.
1994 // Assume that the difference is small, but we don't know which is first.
1995 // Therefore try in alternating directions.
1996 int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
1997
1998 uint16_t i;
1999 uint32_t nttmp1, nttmp2;
2000
2001 if (nt1 == nt2) return 0;
2002
2003 nttmp1 = nt1;
2004 nttmp2 = nt2;
2005
2006 for (i = 1; i < 32768; i++) {
2007 nttmp1 = prng_successor(nttmp1, 1);
2008 if (nttmp1 == nt2) return i;
2009 nttmp2 = prng_successor(nttmp2, 1);
2010 if (nttmp2 == nt1) return -i;
2011 }
2012
2013 return(-99999); // either nt1 or nt2 are invalid nonces
2014 }
2015
2016
2017 //-----------------------------------------------------------------------------
2018 // Recover several bits of the cypher stream. This implements (first stages of)
2019 // the algorithm described in "The Dark Side of Security by Obscurity and
2020 // Cloning MiFare Classic Rail and Building Passes, Anywhere, Anytime"
2021 // (article by Nicolas T. Courtois, 2009)
2022 //-----------------------------------------------------------------------------
2023 void ReaderMifare(bool first_try)
2024 {
2025 // Mifare AUTH
2026 uint8_t mf_auth[] = { 0x60,0x00,0xf5,0x7b };
2027 uint8_t mf_nr_ar[] = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
2028 static uint8_t mf_nr_ar3;
2029
2030 uint8_t receivedAnswer[MAX_MIFARE_FRAME_SIZE];
2031 uint8_t receivedAnswerPar[MAX_MIFARE_PARITY_SIZE];
2032
2033 // free eventually allocated BigBuf memory. We want all for tracing.
2034 BigBuf_free();
2035
2036 iso14a_clear_trace();
2037 iso14a_set_tracing(TRUE);
2038
2039 byte_t nt_diff = 0;
2040 uint8_t par[1] = {0}; // maximum 8 Bytes to be sent here, 1 byte parity is therefore enough
2041 static byte_t par_low = 0;
2042 bool led_on = TRUE;
2043 uint8_t uid[10] ={0};
2044 uint32_t cuid;
2045
2046 uint32_t nt = 0;
2047 uint32_t previous_nt = 0;
2048 static uint32_t nt_attacked = 0;
2049 byte_t par_list[8] = {0x00};
2050 byte_t ks_list[8] = {0x00};
2051
2052 static uint32_t sync_time;
2053 static uint32_t sync_cycles;
2054 int catch_up_cycles = 0;
2055 int last_catch_up = 0;
2056 uint16_t consecutive_resyncs = 0;
2057 int isOK = 0;
2058
2059 if (first_try) {
2060 mf_nr_ar3 = 0;
2061 iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
2062 sync_time = GetCountSspClk() & 0xfffffff8;
2063 sync_cycles = 65536; // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
2064 nt_attacked = 0;
2065 nt = 0;
2066 par[0] = 0;
2067 }
2068 else {
2069 // we were unsuccessful on a previous call. Try another READER nonce (first 3 parity bits remain the same)
2070 mf_nr_ar3++;
2071 mf_nr_ar[3] = mf_nr_ar3;
2072 par[0] = par_low;
2073 }
2074
2075 LED_A_ON();
2076 LED_B_OFF();
2077 LED_C_OFF();
2078
2079
2080 for(uint16_t i = 0; TRUE; i++) {
2081
2082 WDT_HIT();
2083
2084 // Test if the action was cancelled
2085 if(BUTTON_PRESS()) {
2086 break;
2087 }
2088
2089 LED_C_ON();
2090
2091 if(!iso14443a_select_card(uid, NULL, &cuid)) {
2092 if (MF_DBGLEVEL >= 1) Dbprintf("Mifare: Can't select card");
2093 continue;
2094 }
2095
2096 sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
2097 catch_up_cycles = 0;
2098
2099 // if we missed the sync time already, advance to the next nonce repeat
2100 while(GetCountSspClk() > sync_time) {
2101 sync_time = (sync_time & 0xfffffff8) + sync_cycles;
2102 }
2103
2104 // Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked)
2105 ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
2106
2107 // Receive the (4 Byte) "random" nonce
2108 if (!ReaderReceive(receivedAnswer, receivedAnswerPar)) {
2109 if (MF_DBGLEVEL >= 1) Dbprintf("Mifare: Couldn't receive tag nonce");
2110 continue;
2111 }
2112
2113 previous_nt = nt;
2114 nt = bytes_to_num(receivedAnswer, 4);
2115
2116 // Transmit reader nonce with fake par
2117 ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar), par, NULL);
2118
2119 if (first_try && previous_nt && !nt_attacked) { // we didn't calibrate our clock yet
2120 int nt_distance = dist_nt(previous_nt, nt);
2121 if (nt_distance == 0) {
2122 nt_attacked = nt;
2123 }
2124 else {
2125 if (nt_distance == -99999) { // invalid nonce received, try again
2126 continue;
2127 }
2128 sync_cycles = (sync_cycles - nt_distance);
2129 if (MF_DBGLEVEL >= 3) Dbprintf("calibrating in cycle %d. nt_distance=%d, Sync_cycles: %d\n", i, nt_distance, sync_cycles);
2130 continue;
2131 }
2132 }
2133
2134 if ((nt != nt_attacked) && nt_attacked) { // we somehow lost sync. Try to catch up again...
2135 catch_up_cycles = -dist_nt(nt_attacked, nt);
2136 if (catch_up_cycles == 99999) { // invalid nonce received. Don't resync on that one.
2137 catch_up_cycles = 0;
2138 continue;
2139 }
2140 if (catch_up_cycles == last_catch_up) {
2141 consecutive_resyncs++;
2142 }
2143 else {
2144 last_catch_up = catch_up_cycles;
2145 consecutive_resyncs = 0;
2146 }
2147 if (consecutive_resyncs < 3) {
2148 if (MF_DBGLEVEL >= 3) Dbprintf("Lost sync in cycle %d. nt_distance=%d. Consecutive Resyncs = %d. Trying one time catch up...\n", i, -catch_up_cycles, consecutive_resyncs);
2149 }
2150 else {
2151 sync_cycles = sync_cycles + catch_up_cycles;
2152 if (MF_DBGLEVEL >= 3) Dbprintf("Lost sync in cycle %d for the fourth time consecutively (nt_distance = %d). Adjusting sync_cycles to %d.\n", i, -catch_up_cycles, sync_cycles);
2153 }
2154 continue;
2155 }
2156
2157 consecutive_resyncs = 0;
2158
2159 // Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding
2160 if (ReaderReceive(receivedAnswer, receivedAnswerPar))
2161 {
2162 catch_up_cycles = 8; // the PRNG is delayed by 8 cycles due to the NAC (4Bits = 0x05 encrypted) transfer
2163
2164 if (nt_diff == 0)
2165 {
2166 par_low = par[0] & 0xE0; // there is no need to check all parities for other nt_diff. Parity Bits for mf_nr_ar[0..2] won't change
2167 }
2168
2169 led_on = !led_on;
2170 if(led_on) LED_B_ON(); else LED_B_OFF();
2171
2172 par_list[nt_diff] = SwapBits(par[0], 8);
2173 ks_list[nt_diff] = receivedAnswer[0] ^ 0x05;
2174
2175 // Test if the information is complete
2176 if (nt_diff == 0x07) {
2177 isOK = 1;
2178 break;
2179 }
2180
2181 nt_diff = (nt_diff + 1) & 0x07;
2182 mf_nr_ar[3] = (mf_nr_ar[3] & 0x1F) | (nt_diff << 5);
2183 par[0] = par_low;
2184 } else {
2185 if (nt_diff == 0 && first_try)
2186 {
2187 par[0]++;
2188 } else {
2189 par[0] = ((par[0] & 0x1F) + 1) | par_low;
2190 }
2191 }
2192 }
2193
2194
2195 mf_nr_ar[3] &= 0x1F;
2196
2197 byte_t buf[28];
2198 memcpy(buf + 0, uid, 4);
2199 num_to_bytes(nt, 4, buf + 4);
2200 memcpy(buf + 8, par_list, 8);
2201 memcpy(buf + 16, ks_list, 8);
2202 memcpy(buf + 24, mf_nr_ar, 4);
2203
2204 cmd_send(CMD_ACK,isOK,0,0,buf,28);
2205
2206 // Thats it...
2207 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
2208 LEDsoff();
2209
2210 iso14a_set_tracing(FALSE);
2211 }
2212
2213 /**
2214 *MIFARE 1K simulate.
2215 *
2216 *@param flags :
2217 * FLAG_INTERACTIVE - In interactive mode, we are expected to finish the operation with an ACK
2218 * 4B_FLAG_UID_IN_DATA - means that there is a 4-byte UID in the data-section, we're expected to use that
2219 * 7B_FLAG_UID_IN_DATA - means that there is a 7-byte UID in the data-section, we're expected to use that
2220 * FLAG_NR_AR_ATTACK - means we should collect NR_AR responses for bruteforcing later
2221 *@param exitAfterNReads, exit simulation after n blocks have been read, 0 is inifite
2222 */
2223 void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *datain)
2224 {
2225 int cardSTATE = MFEMUL_NOFIELD;
2226 int _7BUID = 0;
2227 int vHf = 0; // in mV
2228 int res;
2229 uint32_t selTimer = 0;
2230 uint32_t authTimer = 0;
2231 uint16_t len = 0;
2232 uint8_t cardWRBL = 0;
2233 uint8_t cardAUTHSC = 0;
2234 uint8_t cardAUTHKEY = 0xff; // no authentication
2235 uint32_t cardRr = 0;
2236 uint32_t cuid = 0;
2237 //uint32_t rn_enc = 0;
2238 uint32_t ans = 0;
2239 uint32_t cardINTREG = 0;
2240 uint8_t cardINTBLOCK = 0;
2241 struct Crypto1State mpcs = {0, 0};
2242 struct Crypto1State *pcs;
2243 pcs = &mpcs;
2244 uint32_t numReads = 0;//Counts numer of times reader read a block
2245 uint8_t receivedCmd[MAX_MIFARE_FRAME_SIZE];
2246 uint8_t receivedCmd_par[MAX_MIFARE_PARITY_SIZE];
2247 uint8_t response[MAX_MIFARE_FRAME_SIZE];
2248 uint8_t response_par[MAX_MIFARE_PARITY_SIZE];
2249
2250 uint8_t rATQA[] = {0x04, 0x00}; // Mifare classic 1k 4BUID
2251 uint8_t rUIDBCC1[] = {0xde, 0xad, 0xbe, 0xaf, 0x62};
2252 uint8_t rUIDBCC2[] = {0xde, 0xad, 0xbe, 0xaf, 0x62}; // !!!
2253 uint8_t rSAK[] = {0x08, 0xb6, 0xdd};
2254 uint8_t rSAK1[] = {0x04, 0xda, 0x17};
2255
2256 uint8_t rAUTH_NT[] = {0x01, 0x02, 0x03, 0x04};
2257 uint8_t rAUTH_AT[] = {0x00, 0x00, 0x00, 0x00};
2258
2259 //Here, we collect UID,NT,AR,NR,UID2,NT2,AR2,NR2
2260 // This can be used in a reader-only attack.
2261 // (it can also be retrieved via 'hf 14a list', but hey...
2262 uint32_t ar_nr_responses[] = {0,0,0,0,0,0,0,0};
2263 uint8_t ar_nr_collected = 0;
2264
2265 // free eventually allocated BigBuf memory but keep Emulator Memory
2266 BigBuf_free_keep_EM();
2267 // clear trace
2268 iso14a_clear_trace();
2269 iso14a_set_tracing(TRUE);
2270
2271 // Authenticate response - nonce
2272 uint32_t nonce = bytes_to_num(rAUTH_NT, 4);
2273
2274 //-- Determine the UID
2275 // Can be set from emulator memory, incoming data
2276 // and can be 7 or 4 bytes long
2277 if (flags & FLAG_4B_UID_IN_DATA)
2278 {
2279 // 4B uid comes from data-portion of packet
2280 memcpy(rUIDBCC1,datain,4);
2281 rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
2282
2283 } else if (flags & FLAG_7B_UID_IN_DATA) {
2284 // 7B uid comes from data-portion of packet
2285 memcpy(&rUIDBCC1[1],datain,3);
2286 memcpy(rUIDBCC2, datain+3, 4);
2287 _7BUID = true;
2288 } else {
2289 // get UID from emul memory
2290 emlGetMemBt(receivedCmd, 7, 1);
2291 _7BUID = !(receivedCmd[0] == 0x00);
2292 if (!_7BUID) { // ---------- 4BUID
2293 emlGetMemBt(rUIDBCC1, 0, 4);
2294 } else { // ---------- 7BUID
2295 emlGetMemBt(&rUIDBCC1[1], 0, 3);
2296 emlGetMemBt(rUIDBCC2, 3, 4);
2297 }
2298 }
2299
2300 /*
2301 * Regardless of what method was used to set the UID, set fifth byte and modify
2302 * the ATQA for 4 or 7-byte UID
2303 */
2304 rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
2305 if (_7BUID) {
2306 rATQA[0] = 0x44;
2307 rUIDBCC1[0] = 0x88;
2308 rUIDBCC2[4] = rUIDBCC2[0] ^ rUIDBCC2[1] ^ rUIDBCC2[2] ^ rUIDBCC2[3];
2309 }
2310
2311 // We need to listen to the high-frequency, peak-detected path.
2312 iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
2313
2314
2315 if (MF_DBGLEVEL >= 1) {
2316 if (!_7BUID) {
2317 Dbprintf("4B UID: %02x%02x%02x%02x",
2318 rUIDBCC1[0], rUIDBCC1[1], rUIDBCC1[2], rUIDBCC1[3]);
2319 } else {
2320 Dbprintf("7B UID: (%02x)%02x%02x%02x%02x%02x%02x%02x",
2321 rUIDBCC1[0], rUIDBCC1[1], rUIDBCC1[2], rUIDBCC1[3],
2322 rUIDBCC2[0], rUIDBCC2[1] ,rUIDBCC2[2], rUIDBCC2[3]);
2323 }
2324 }
2325
2326 bool finished = FALSE;
2327 while (!BUTTON_PRESS() && !finished) {
2328 WDT_HIT();
2329
2330 // find reader field
2331 // Vref = 3300mV, and an 10:1 voltage divider on the input
2332 // can measure voltages up to 33000 mV
2333 if (cardSTATE == MFEMUL_NOFIELD) {
2334 vHf = (33000 * AvgAdc(ADC_CHAN_HF)) >> 10;
2335 if (vHf > MF_MINFIELDV) {
2336 cardSTATE_TO_IDLE();
2337 LED_A_ON();
2338 }
2339 }
2340 if(cardSTATE == MFEMUL_NOFIELD) continue;
2341
2342 //Now, get data
2343
2344 res = EmGetCmd(receivedCmd, &len, receivedCmd_par);
2345 if (res == 2) { //Field is off!
2346 cardSTATE = MFEMUL_NOFIELD;
2347 LEDsoff();
2348 continue;
2349 } else if (res == 1) {
2350 break; //return value 1 means button press
2351 }
2352
2353 // REQ or WUP request in ANY state and WUP in HALTED state
2354 if (len == 1 && ((receivedCmd[0] == 0x26 && cardSTATE != MFEMUL_HALTED) || receivedCmd[0] == 0x52)) {
2355 selTimer = GetTickCount();
2356 EmSendCmdEx(rATQA, sizeof(rATQA), (receivedCmd[0] == 0x52));
2357 cardSTATE = MFEMUL_SELECT1;
2358
2359 // init crypto block
2360 LED_B_OFF();
2361 LED_C_OFF();
2362 crypto1_destroy(pcs);
2363 cardAUTHKEY = 0xff;
2364 continue;
2365 }
2366
2367 switch (cardSTATE) {
2368 case MFEMUL_NOFIELD:
2369 case MFEMUL_HALTED:
2370 case MFEMUL_IDLE:{
2371 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2372 break;
2373 }
2374 case MFEMUL_SELECT1:{
2375 // select all
2376 if (len == 2 && (receivedCmd[0] == 0x93 && receivedCmd[1] == 0x20)) {
2377 if (MF_DBGLEVEL >= 4) Dbprintf("SELECT ALL received");
2378 EmSendCmd(rUIDBCC1, sizeof(rUIDBCC1));
2379 break;
2380 }
2381
2382 if (MF_DBGLEVEL >= 4 && len == 9 && receivedCmd[0] == 0x93 && receivedCmd[1] == 0x70 )
2383 {
2384 Dbprintf("SELECT %02x%02x%02x%02x received",receivedCmd[2],receivedCmd[3],receivedCmd[4],receivedCmd[5]);
2385 }
2386 // select card
2387 if (len == 9 &&
2388 (receivedCmd[0] == 0x93 && receivedCmd[1] == 0x70 && memcmp(&receivedCmd[2], rUIDBCC1, 4) == 0)) {
2389 EmSendCmd(_7BUID?rSAK1:rSAK, _7BUID?sizeof(rSAK1):sizeof(rSAK));
2390 cuid = bytes_to_num(rUIDBCC1, 4);
2391 if (!_7BUID) {
2392 cardSTATE = MFEMUL_WORK;
2393 LED_B_ON();
2394 if (MF_DBGLEVEL >= 4) Dbprintf("--> WORK. anticol1 time: %d", GetTickCount() - selTimer);
2395 break;
2396 } else {
2397 cardSTATE = MFEMUL_SELECT2;
2398 }
2399 }
2400 break;
2401 }
2402 case MFEMUL_AUTH1:{
2403 if( len != 8)
2404 {
2405 cardSTATE_TO_IDLE();
2406 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2407 break;
2408 }
2409 uint32_t ar = bytes_to_num(receivedCmd, 4);
2410 uint32_t nr = bytes_to_num(&receivedCmd[4], 4);
2411
2412 //Collect AR/NR
2413 if(ar_nr_collected < 2){
2414 if(ar_nr_responses[2] != ar)
2415 {// Avoid duplicates... probably not necessary, ar should vary.
2416 ar_nr_responses[ar_nr_collected*4] = cuid;
2417 ar_nr_responses[ar_nr_collected*4+1] = nonce;
2418 ar_nr_responses[ar_nr_collected*4+2] = ar;
2419 ar_nr_responses[ar_nr_collected*4+3] = nr;
2420 ar_nr_collected++;
2421 }
2422 }
2423
2424 // --- crypto
2425 crypto1_word(pcs, ar , 1);
2426 cardRr = nr ^ crypto1_word(pcs, 0, 0);
2427
2428 // test if auth OK
2429 if (cardRr != prng_successor(nonce, 64)){
2430 if (MF_DBGLEVEL >= 2) Dbprintf("AUTH FAILED for sector %d with key %c. cardRr=%08x, succ=%08x",
2431 cardAUTHSC, cardAUTHKEY == 0 ? 'A' : 'B',
2432 cardRr, prng_successor(nonce, 64));
2433 // Shouldn't we respond anything here?
2434 // Right now, we don't nack or anything, which causes the
2435 // reader to do a WUPA after a while. /Martin
2436 // -- which is the correct response. /piwi
2437 cardSTATE_TO_IDLE();
2438 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2439 break;
2440 }
2441
2442 ans = prng_successor(nonce, 96) ^ crypto1_word(pcs, 0, 0);
2443
2444 num_to_bytes(ans, 4, rAUTH_AT);
2445 // --- crypto
2446 EmSendCmd(rAUTH_AT, sizeof(rAUTH_AT));
2447 LED_C_ON();
2448 cardSTATE = MFEMUL_WORK;
2449 if (MF_DBGLEVEL >= 4) Dbprintf("AUTH COMPLETED for sector %d with key %c. time=%d",
2450 cardAUTHSC, cardAUTHKEY == 0 ? 'A' : 'B',
2451 GetTickCount() - authTimer);
2452 break;
2453 }
2454 case MFEMUL_SELECT2:{
2455 if (!len) {
2456 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2457 break;
2458 }
2459 if (len == 2 && (receivedCmd[0] == 0x95 && receivedCmd[1] == 0x20)) {
2460 EmSendCmd(rUIDBCC2, sizeof(rUIDBCC2));
2461 break;
2462 }
2463
2464 // select 2 card
2465 if (len == 9 &&
2466 (receivedCmd[0] == 0x95 && receivedCmd[1] == 0x70 && memcmp(&receivedCmd[2], rUIDBCC2, 4) == 0)) {
2467 EmSendCmd(rSAK, sizeof(rSAK));
2468 cuid = bytes_to_num(rUIDBCC2, 4);
2469 cardSTATE = MFEMUL_WORK;
2470 LED_B_ON();
2471 if (MF_DBGLEVEL >= 4) Dbprintf("--> WORK. anticol2 time: %d", GetTickCount() - selTimer);
2472 break;
2473 }
2474
2475 // i guess there is a command). go into the work state.
2476 if (len != 4) {
2477 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2478 break;
2479 }
2480 cardSTATE = MFEMUL_WORK;
2481 //goto lbWORK;
2482 //intentional fall-through to the next case-stmt
2483 }
2484
2485 case MFEMUL_WORK:{
2486 if (len == 0) {
2487 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2488 break;
2489 }
2490
2491 bool encrypted_data = (cardAUTHKEY != 0xFF) ;
2492
2493 if(encrypted_data) {
2494 // decrypt seqence
2495 mf_crypto1_decrypt(pcs, receivedCmd, len);
2496 }
2497
2498 if (len == 4 && (receivedCmd[0] == 0x60 || receivedCmd[0] == 0x61)) {
2499 authTimer = GetTickCount();
2500 cardAUTHSC = receivedCmd[1] / 4; // received block num
2501 cardAUTHKEY = receivedCmd[0] - 0x60;
2502 crypto1_destroy(pcs);//Added by martin
2503 crypto1_create(pcs, emlGetKey(cardAUTHSC, cardAUTHKEY));
2504
2505 if (!encrypted_data) { // first authentication
2506 if (MF_DBGLEVEL >= 4) Dbprintf("Reader authenticating for block %d (0x%02x) with key %d",receivedCmd[1] ,receivedCmd[1],cardAUTHKEY );
2507
2508 crypto1_word(pcs, cuid ^ nonce, 0);//Update crypto state
2509 num_to_bytes(nonce, 4, rAUTH_AT); // Send nonce
2510 } else { // nested authentication
2511 if (MF_DBGLEVEL >= 4) Dbprintf("Reader doing nested authentication for block %d (0x%02x) with key %d",receivedCmd[1] ,receivedCmd[1],cardAUTHKEY );
2512 ans = nonce ^ crypto1_word(pcs, cuid ^ nonce, 0);
2513 num_to_bytes(ans, 4, rAUTH_AT);
2514 }
2515 EmSendCmd(rAUTH_AT, sizeof(rAUTH_AT));
2516 //Dbprintf("Sending rAUTH %02x%02x%02x%02x", rAUTH_AT[0],rAUTH_AT[1],rAUTH_AT[2],rAUTH_AT[3]);
2517 cardSTATE = MFEMUL_AUTH1;
2518 break;
2519 }
2520
2521 // rule 13 of 7.5.3. in ISO 14443-4. chaining shall be continued
2522 // BUT... ACK --> NACK
2523 if (len == 1 && receivedCmd[0] == CARD_ACK) {
2524 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2525 break;
2526 }
2527
2528 // rule 12 of 7.5.3. in ISO 14443-4. R(NAK) --> R(ACK)
2529 if (len == 1 && receivedCmd[0] == CARD_NACK_NA) {
2530 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
2531 break;
2532 }
2533
2534 if(len != 4) {
2535 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2536 break;
2537 }
2538
2539 if(receivedCmd[0] == 0x30 // read block
2540 || receivedCmd[0] == 0xA0 // write block
2541 || receivedCmd[0] == 0xC0 // inc
2542 || receivedCmd[0] == 0xC1 // dec
2543 || receivedCmd[0] == 0xC2 // restore
2544 || receivedCmd[0] == 0xB0) { // transfer
2545 if (receivedCmd[1] >= 16 * 4) {
2546 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2547 if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02) on out of range block: %d (0x%02x), nacking",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
2548 break;
2549 }
2550
2551 if (receivedCmd[1] / 4 != cardAUTHSC) {
2552 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2553 if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02) on block (0x%02x) not authenticated for (0x%02x), nacking",receivedCmd[0],receivedCmd[1],cardAUTHSC);
2554 break;
2555 }
2556 }
2557 // read block
2558 if (receivedCmd[0] == 0x30) {
2559 if (MF_DBGLEVEL >= 4) {
2560 Dbprintf("Reader reading block %d (0x%02x)",receivedCmd[1],receivedCmd[1]);
2561 }
2562 emlGetMem(response, receivedCmd[1], 1);
2563 AppendCrc14443a(response, 16);
2564 mf_crypto1_encrypt(pcs, response, 18, response_par);
2565 EmSendCmdPar(response, 18, response_par);
2566 numReads++;
2567 if(exitAfterNReads > 0 && numReads == exitAfterNReads) {
2568 Dbprintf("%d reads done, exiting", numReads);
2569 finished = true;
2570 }
2571 break;
2572 }
2573 // write block
2574 if (receivedCmd[0] == 0xA0) {
2575 if (MF_DBGLEVEL >= 4) Dbprintf("RECV 0xA0 write block %d (%02x)",receivedCmd[1],receivedCmd[1]);
2576 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
2577 cardSTATE = MFEMUL_WRITEBL2;
2578 cardWRBL = receivedCmd[1];
2579 break;
2580 }
2581 // increment, decrement, restore
2582 if (receivedCmd[0] == 0xC0 || receivedCmd[0] == 0xC1 || receivedCmd[0] == 0xC2) {
2583 if (MF_DBGLEVEL >= 4) Dbprintf("RECV 0x%02x inc(0xC1)/dec(0xC0)/restore(0xC2) block %d (%02x)",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
2584 if (emlCheckValBl(receivedCmd[1])) {
2585 if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate on block, but emlCheckValBl failed, nacking");
2586 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2587 break;
2588 }
2589 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
2590 if (receivedCmd[0] == 0xC1)
2591 cardSTATE = MFEMUL_INTREG_INC;
2592 if (receivedCmd[0] == 0xC0)
2593 cardSTATE = MFEMUL_INTREG_DEC;
2594 if (receivedCmd[0] == 0xC2)
2595 cardSTATE = MFEMUL_INTREG_REST;
2596 cardWRBL = receivedCmd[1];
2597 break;
2598 }
2599 // transfer
2600 if (receivedCmd[0] == 0xB0) {
2601 if (MF_DBGLEVEL >= 4) Dbprintf("RECV 0x%02x transfer block %d (%02x)",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
2602 if (emlSetValBl(cardINTREG, cardINTBLOCK, receivedCmd[1]))
2603 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2604 else
2605 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
2606 break;
2607 }
2608 // halt
2609 if (receivedCmd[0] == 0x50 && receivedCmd[1] == 0x00) {
2610 LED_B_OFF();
2611 LED_C_OFF();
2612 cardSTATE = MFEMUL_HALTED;
2613 if (MF_DBGLEVEL >= 4) Dbprintf("--> HALTED. Selected time: %d ms", GetTickCount() - selTimer);
2614 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2615 break;
2616 }
2617 // RATS
2618 if (receivedCmd[0] == 0xe0) {//RATS
2619 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2620 break;
2621 }
2622 // command not allowed
2623 if (MF_DBGLEVEL >= 4) Dbprintf("Received command not allowed, nacking");
2624 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2625 break;
2626 }
2627 case MFEMUL_WRITEBL2:{
2628 if (len == 18){
2629 mf_crypto1_decrypt(pcs, receivedCmd, len);
2630 emlSetMem(receivedCmd, cardWRBL, 1);
2631 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
2632 cardSTATE = MFEMUL_WORK;
2633 } else {
2634 cardSTATE_TO_IDLE();
2635 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2636 }
2637 break;
2638 }
2639
2640 case MFEMUL_INTREG_INC:{
2641 mf_crypto1_decrypt(pcs, receivedCmd, len);
2642 memcpy(&ans, receivedCmd, 4);
2643 if (emlGetValBl(&cardINTREG, &cardINTBLOCK, cardWRBL)) {
2644 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2645 cardSTATE_TO_IDLE();
2646 break;
2647 }
2648 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2649 cardINTREG = cardINTREG + ans;
2650 cardSTATE = MFEMUL_WORK;
2651 break;
2652 }
2653 case MFEMUL_INTREG_DEC:{
2654 mf_crypto1_decrypt(pcs, receivedCmd, len);
2655 memcpy(&ans, receivedCmd, 4);
2656 if (emlGetValBl(&cardINTREG, &cardINTBLOCK, cardWRBL)) {
2657 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2658 cardSTATE_TO_IDLE();
2659 break;
2660 }
2661 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2662 cardINTREG = cardINTREG - ans;
2663 cardSTATE = MFEMUL_WORK;
2664 break;
2665 }
2666 case MFEMUL_INTREG_REST:{
2667 mf_crypto1_decrypt(pcs, receivedCmd, len);
2668 memcpy(&ans, receivedCmd, 4);
2669 if (emlGetValBl(&cardINTREG, &cardINTBLOCK, cardWRBL)) {
2670 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2671 cardSTATE_TO_IDLE();
2672 break;
2673 }
2674 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2675 cardSTATE = MFEMUL_WORK;
2676 break;
2677 }
2678 }
2679 }
2680
2681 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
2682 LEDsoff();
2683
2684 if(flags & FLAG_INTERACTIVE)// Interactive mode flag, means we need to send ACK
2685 {
2686 //May just aswell send the collected ar_nr in the response aswell
2687 cmd_send(CMD_ACK,CMD_SIMULATE_MIFARE_CARD,0,0,&ar_nr_responses,ar_nr_collected*4*4);
2688 }
2689
2690 if(flags & FLAG_NR_AR_ATTACK)
2691 {
2692 if(ar_nr_collected > 1) {
2693 Dbprintf("Collected two pairs of AR/NR which can be used to extract keys from reader:");
2694 Dbprintf("../tools/mfkey/mfkey32 %08x %08x %08x %08x %08x %08x",
2695 ar_nr_responses[0], // UID
2696 ar_nr_responses[1], //NT
2697 ar_nr_responses[2], //AR1
2698 ar_nr_responses[3], //NR1
2699 ar_nr_responses[6], //AR2
2700 ar_nr_responses[7] //NR2
2701 );
2702 } else {
2703 Dbprintf("Failed to obtain two AR/NR pairs!");
2704 if(ar_nr_collected >0) {
2705 Dbprintf("Only got these: UID=%08x, nonce=%08x, AR1=%08x, NR1=%08x",
2706 ar_nr_responses[0], // UID
2707 ar_nr_responses[1], //NT
2708 ar_nr_responses[2], //AR1
2709 ar_nr_responses[3] //NR1
2710 );
2711 }
2712 }
2713 }
2714 if (MF_DBGLEVEL >= 1) Dbprintf("Emulator stopped. Tracing: %d trace length: %d ", tracing, traceLen);
2715 }
2716
2717
2718
2719 //-----------------------------------------------------------------------------
2720 // MIFARE sniffer.
2721 //
2722 //-----------------------------------------------------------------------------
2723 void RAMFUNC SniffMifare(uint8_t param) {
2724 // param:
2725 // bit 0 - trigger from first card answer
2726 // bit 1 - trigger from first reader 7-bit request
2727
2728 // C(red) A(yellow) B(green)
2729 LEDsoff();
2730 // init trace buffer
2731 iso14a_clear_trace();
2732 iso14a_set_tracing(TRUE);
2733
2734 // The command (reader -> tag) that we're receiving.
2735 // The length of a received command will in most cases be no more than 18 bytes.
2736 // So 32 should be enough!
2737 uint8_t receivedCmd[MAX_MIFARE_FRAME_SIZE];
2738 uint8_t receivedCmdPar[MAX_MIFARE_PARITY_SIZE];
2739 // The response (tag -> reader) that we're receiving.
2740 uint8_t receivedResponse[MAX_MIFARE_FRAME_SIZE];
2741 uint8_t receivedResponsePar[MAX_MIFARE_PARITY_SIZE];
2742
2743 // As we receive stuff, we copy it from receivedCmd or receivedResponse
2744 // into trace, along with its length and other annotations.
2745 //uint8_t *trace = (uint8_t *)BigBuf;
2746
2747 // free eventually allocated BigBuf memory
2748 BigBuf_free();
2749 // allocate the DMA buffer, used to stream samples from the FPGA
2750 uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
2751 uint8_t *data = dmaBuf;
2752 uint8_t previous_data = 0;
2753 int maxDataLen = 0;
2754 int dataLen = 0;
2755 bool ReaderIsActive = FALSE;
2756 bool TagIsActive = FALSE;
2757
2758 iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
2759
2760 // Set up the demodulator for tag -> reader responses.
2761 DemodInit(receivedResponse, receivedResponsePar);
2762
2763 // Set up the demodulator for the reader -> tag commands
2764 UartInit(receivedCmd, receivedCmdPar);
2765
2766 // Setup for the DMA.
2767 FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE); // set transfer address and number of bytes. Start transfer.
2768
2769 LED_D_OFF();
2770
2771 // init sniffer
2772 MfSniffInit();
2773
2774 // And now we loop, receiving samples.
2775 for(uint32_t sniffCounter = 0; TRUE; ) {
2776
2777 if(BUTTON_PRESS()) {
2778 DbpString("cancelled by button");
2779 break;
2780 }
2781
2782 LED_A_ON();
2783 WDT_HIT();
2784
2785 if ((sniffCounter & 0x0000FFFF) == 0) { // from time to time
2786 // check if a transaction is completed (timeout after 2000ms).
2787 // if yes, stop the DMA transfer and send what we have so far to the client
2788 if (MfSniffSend(2000)) {
2789 // Reset everything - we missed some sniffed data anyway while the DMA was stopped
2790 sniffCounter = 0;
2791 data = dmaBuf;
2792 maxDataLen = 0;
2793 ReaderIsActive = FALSE;
2794 TagIsActive = FALSE;
2795 FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE); // set transfer address and number of bytes. Start transfer.
2796 }
2797 }
2798
2799 int register readBufDataP = data - dmaBuf; // number of bytes we have processed so far
2800 int register dmaBufDataP = DMA_BUFFER_SIZE - AT91C_BASE_PDC_SSC->PDC_RCR; // number of bytes already transferred
2801 if (readBufDataP <= dmaBufDataP){ // we are processing the same block of data which is currently being transferred
2802 dataLen = dmaBufDataP - readBufDataP; // number of bytes still to be processed
2803 } else {
2804 dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP; // number of bytes still to be processed
2805 }
2806 // test for length of buffer
2807 if(dataLen > maxDataLen) { // we are more behind than ever...
2808 maxDataLen = dataLen;
2809 if(dataLen > (9 * DMA_BUFFER_SIZE / 10)) {
2810 Dbprintf("blew circular buffer! dataLen=0x%x", dataLen);
2811 break;
2812 }
2813 }
2814 if(dataLen < 1) continue;
2815
2816 // primary buffer was stopped ( <-- we lost data!
2817 if (!AT91C_BASE_PDC_SSC->PDC_RCR) {
2818 AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) dmaBuf;
2819 AT91C_BASE_PDC_SSC->PDC_RCR = DMA_BUFFER_SIZE;
2820 Dbprintf("RxEmpty ERROR!!! data length:%d", dataLen); // temporary
2821 }
2822 // secondary buffer sets as primary, secondary buffer was stopped
2823 if (!AT91C_BASE_PDC_SSC->PDC_RNCR) {
2824 AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
2825 AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
2826 }
2827
2828 LED_A_OFF();
2829
2830 if (sniffCounter & 0x01) {
2831
2832 if(!TagIsActive) { // no need to try decoding tag data if the reader is sending
2833 uint8_t readerdata = (previous_data & 0xF0) | (*data >> 4);
2834 if(MillerDecoding(readerdata, (sniffCounter-1)*4)) {
2835 LED_C_INV();
2836 if (MfSniffLogic(receivedCmd, Uart.len, Uart.parity, Uart.bitCount, TRUE)) break;
2837
2838 /* And ready to receive another command. */
2839 UartReset();
2840
2841 /* And also reset the demod code */
2842 DemodReset();
2843 }
2844 ReaderIsActive = (Uart.state != STATE_UNSYNCD);
2845 }
2846
2847 if(!ReaderIsActive) { // no need to try decoding tag data if the reader is sending
2848 uint8_t tagdata = (previous_data << 4) | (*data & 0x0F);
2849 if(ManchesterDecoding(tagdata, 0, (sniffCounter-1)*4)) {
2850 LED_C_INV();
2851
2852 if (MfSniffLogic(receivedResponse, Demod.len, Demod.parity, Demod.bitCount, FALSE)) break;
2853
2854 // And ready to receive another response.
2855 DemodReset();
2856 }
2857 TagIsActive = (Demod.state != DEMOD_UNSYNCD);
2858 }
2859 }
2860
2861 previous_data = *data;
2862 sniffCounter++;
2863 data++;
2864 if(data == dmaBuf + DMA_BUFFER_SIZE) {
2865 data = dmaBuf;
2866 }
2867
2868 } // main cycle
2869
2870 DbpString("COMMAND FINISHED");
2871
2872 FpgaDisableSscDma();
2873 MfSniffEnd();
2874
2875 Dbprintf("maxDataLen=%x, Uart.state=%x, Uart.len=%x", maxDataLen, Uart.state, Uart.len);
2876 LEDsoff();
2877 }
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