//----------------------------------------------------------------------------- // Merlok - June 2011, 2012 // Gerhard de Koning Gans - May 2008 // Hagen Fritsch - June 2010 // // This code is licensed to you under the terms of the GNU GPL, version 2 or, // at your option, any later version. See the LICENSE.txt file for the text of // the license. //----------------------------------------------------------------------------- // Routines to support ISO 14443 type A. //----------------------------------------------------------------------------- #include "iso14443a.h" #include "string.h" #include "proxmark3_arm.h" #include "cmd.h" #include "appmain.h" #include "BigBuf.h" #include "fpgaloader.h" #include "ticks.h" #include "dbprint.h" #include "util.h" #include "parity.h" #include "mifareutil.h" #include "commonutil.h" #include "crc16.h" #include "protocols.h" #define MAX_ISO14A_TIMEOUT 524288 static uint32_t iso14a_timeout; // if iso14443a not active - transmit/receive dont try to execute static bool hf_field_active = false; uint8_t colpos = 0; int rsamples = 0; uint8_t trigger = 0; // the block number for the ISO14443-4 PCB static uint8_t iso14_pcb_blocknum = 0; // // ISO14443 timing: // // minimum time between the start bits of consecutive transfers from reader to tag: 7000 carrier (13.56MHz) cycles #define REQUEST_GUARD_TIME (7000/16 + 1) // minimum time between last modulation of tag and next start bit from reader to tag: 1172 carrier cycles #define FRAME_DELAY_TIME_PICC_TO_PCD (1172/16 + 1) // bool LastCommandWasRequest = false; // // Total delays including SSC-Transfers between ARM and FPGA. These are in carrier clock cycles (1/13,56MHz) // // When the PM acts as reader and is receiving tag data, it takes // 3 ticks delay in the AD converter // 16 ticks until the modulation detector completes and sets curbit // 8 ticks until bit_to_arm is assigned from curbit // 8*16 ticks for the transfer from FPGA to ARM // 4*16 ticks until we measure the time // - 8*16 ticks because we measure the time of the previous transfer #define DELAY_AIR2ARM_AS_READER (3 + 16 + 8 + 8*16 + 4*16 - 8*16) // When the PM acts as a reader and is sending, it takes // 4*16 ticks until we can write data to the sending hold register // 8*16 ticks until the SHR is transferred to the Sending Shift Register // 8 ticks until the first transfer starts // 8 ticks later the FPGA samples the data // 1 tick to assign mod_sig_coil #define DELAY_ARM2AIR_AS_READER (4*16 + 8*16 + 8 + 8 + 1) // The FPGA will report its internal sending delay in uint16_t FpgaSendQueueDelay; // the 5 first bits are the number of bits buffered in mod_sig_buf // the last three bits are the remaining ticks/2 after the mod_sig_buf shift #define DELAY_FPGA_QUEUE (FpgaSendQueueDelay<<1) // When the PM acts as tag and is sending, it takes // 4*16 + 8 ticks until we can write data to the sending hold register // 8*16 ticks until the SHR is transferred to the Sending Shift Register // 8 ticks later the FPGA samples the first data // + 16 ticks until assigned to mod_sig // + 1 tick to assign mod_sig_coil // + a varying number of ticks in the FPGA Delay Queue (mod_sig_buf) #define DELAY_ARM2AIR_AS_TAG (4*16 + 8 + 8*16 + 8 + 16 + 1 + DELAY_FPGA_QUEUE) // When the PM acts as sniffer and is receiving tag data, it takes // 3 ticks A/D conversion // 14 ticks to complete the modulation detection // 8 ticks (on average) until the result is stored in to_arm // + the delays in transferring data - which is the same for // sniffing reader and tag data and therefore not relevant #define DELAY_TAG_AIR2ARM_AS_SNIFFER (3 + 14 + 8) // When the PM acts as sniffer and is receiving reader data, it takes // 2 ticks delay in analogue RF receiver (for the falling edge of the // start bit, which marks the start of the communication) // 3 ticks A/D conversion // 8 ticks on average until the data is stored in to_arm. // + the delays in transferring data - which is the same for // sniffing reader and tag data and therefore not relevant #define DELAY_READER_AIR2ARM_AS_SNIFFER (2 + 3 + 8) //variables used for timing purposes: //these are in ssp_clk cycles: static uint32_t NextTransferTime; static uint32_t LastTimeProxToAirStart; static uint32_t LastProxToAirDuration; // CARD TO READER - manchester // Sequence D: 11110000 modulation with subcarrier during first half // Sequence E: 00001111 modulation with subcarrier during second half // Sequence F: 00000000 no modulation with subcarrier // Sequence COLL: 11111111 load modulation over the full bitlength. // Tricks the reader to think that multiple cards answer (at least one card with 1 and at least one card with 0). // READER TO CARD - miller // Sequence X: 00001100 drop after half a period // Sequence Y: 00000000 no drop // Sequence Z: 11000000 drop at start #define SEC_D 0xf0 #define SEC_E 0x0f #define SEC_F 0x00 #define SEC_COLL 0xff #define SEC_X 0x0c #define SEC_Y 0x00 #define SEC_Z 0xc0 void iso14a_set_trigger(bool enable) { trigger = enable; } void iso14a_set_timeout(uint32_t timeout) { iso14a_timeout = timeout + (DELAY_AIR2ARM_AS_READER + DELAY_ARM2AIR_AS_READER) / (16 * 8) + 2; } uint32_t iso14a_get_timeout(void) { return iso14a_timeout - (DELAY_AIR2ARM_AS_READER + DELAY_ARM2AIR_AS_READER) / (16 * 8) - 2; } //----------------------------------------------------------------------------- // Generate the parity value for a byte sequence //----------------------------------------------------------------------------- void GetParity(const uint8_t *pbtCmd, uint16_t len, uint8_t *par) { uint16_t paritybit_cnt = 0; uint16_t paritybyte_cnt = 0; uint8_t parityBits = 0; for (uint16_t i = 0; i < len; i++) { // Generate the parity bits parityBits |= ((oddparity8(pbtCmd[i])) << (7 - paritybit_cnt)); if (paritybit_cnt == 7) { par[paritybyte_cnt] = parityBits; // save 8 Bits parity parityBits = 0; // and advance to next Parity Byte paritybyte_cnt++; paritybit_cnt = 0; } else { paritybit_cnt++; } } // save remaining parity bits par[paritybyte_cnt] = parityBits; } //============================================================================= // ISO 14443 Type A - Miller decoder //============================================================================= // Basics: // This decoder is used when the PM3 acts as a tag. // The reader will generate "pauses" by temporarily switching of the field. // At the PM3 antenna we will therefore measure a modulated antenna voltage. // The FPGA does a comparison with a threshold and would deliver e.g.: // ........ 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 ....... // The Miller decoder needs to identify the following sequences: // 2 (or 3) ticks pause followed by 6 (or 5) ticks unmodulated: pause at beginning - Sequence Z ("start of communication" or a "0") // 8 ticks without a modulation: no pause - Sequence Y (a "0" or "end of communication" or "no information") // 4 ticks unmodulated followed by 2 (or 3) ticks pause: pause in second half - Sequence X (a "1") // Note 1: the bitstream may start at any time. We therefore need to sync. // Note 2: the interpretation of Sequence Y and Z depends on the preceding sequence. //----------------------------------------------------------------------------- static tUart14a Uart; // Lookup-Table to decide if 4 raw bits are a modulation. // We accept the following: // 0001 - a 3 tick wide pause // 0011 - a 2 tick wide pause, or a three tick wide pause shifted left // 0111 - a 2 tick wide pause shifted left // 1001 - a 2 tick wide pause shifted right const bool Mod_Miller_LUT[] = { false, true, false, true, false, false, false, true, false, true, false, false, false, false, false, false }; #define IsMillerModulationNibble1(b) (Mod_Miller_LUT[(b & 0x000000F0) >> 4]) #define IsMillerModulationNibble2(b) (Mod_Miller_LUT[(b & 0x0000000F)]) tUart14a *GetUart14a() { return &Uart; } void Uart14aReset(void) { Uart.state = STATE_14A_UNSYNCD; Uart.bitCount = 0; Uart.len = 0; // number of decoded data bytes Uart.parityLen = 0; // number of decoded parity bytes Uart.shiftReg = 0; // shiftreg to hold decoded data bits Uart.parityBits = 0; // holds 8 parity bits Uart.startTime = 0; Uart.endTime = 0; Uart.fourBits = 0x00000000; // clear the buffer for 4 Bits Uart.posCnt = 0; Uart.syncBit = 9999; } void Uart14aInit(uint8_t *data, uint8_t *par) { Uart.output = data; Uart.parity = par; Uart14aReset(); } // use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time) { Uart.fourBits = (Uart.fourBits << 8) | bit; if (Uart.state == STATE_14A_UNSYNCD) { // not yet synced Uart.syncBit = 9999; // not set // 00x11111 2|3 ticks pause followed by 6|5 ticks unmodulated Sequence Z (a "0" or "start of communication") // 11111111 8 ticks unmodulation Sequence Y (a "0" or "end of communication" or "no information") // 111100x1 4 ticks unmodulated followed by 2|3 ticks pause Sequence X (a "1") // The start bit is one ore more Sequence Y followed by a Sequence Z (... 11111111 00x11111). We need to distinguish from // Sequence X followed by Sequence Y followed by Sequence Z (111100x1 11111111 00x11111) // we therefore look for a ...xx1111 11111111 00x11111xxxxxx... pattern // (12 '1's followed by 2 '0's, eventually followed by another '0', followed by 5 '1's) #define ISO14443A_STARTBIT_MASK 0x07FFEF80 // mask is 00000111 11111111 11101111 10000000 #define ISO14443A_STARTBIT_PATTERN 0x07FF8F80 // pattern is 00000111 11111111 10001111 10000000 if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 0)) == ISO14443A_STARTBIT_PATTERN >> 0) Uart.syncBit = 7; else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 1)) == ISO14443A_STARTBIT_PATTERN >> 1) Uart.syncBit = 6; else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 2)) == ISO14443A_STARTBIT_PATTERN >> 2) Uart.syncBit = 5; else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 3)) == ISO14443A_STARTBIT_PATTERN >> 3) Uart.syncBit = 4; else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 4)) == ISO14443A_STARTBIT_PATTERN >> 4) Uart.syncBit = 3; else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 5)) == ISO14443A_STARTBIT_PATTERN >> 5) Uart.syncBit = 2; else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 6)) == ISO14443A_STARTBIT_PATTERN >> 6) Uart.syncBit = 1; else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 7)) == ISO14443A_STARTBIT_PATTERN >> 7) Uart.syncBit = 0; if (Uart.syncBit != 9999) { // found a sync bit Uart.startTime = non_real_time ? non_real_time : (GetCountSspClk() & 0xfffffff8); Uart.startTime -= Uart.syncBit; Uart.endTime = Uart.startTime; Uart.state = STATE_14A_START_OF_COMMUNICATION; } } else { if (IsMillerModulationNibble1(Uart.fourBits >> Uart.syncBit)) { if (IsMillerModulationNibble2(Uart.fourBits >> Uart.syncBit)) { // Modulation in both halves - error Uart14aReset(); } else { // Modulation in first half = Sequence Z = logic "0" if (Uart.state == STATE_14A_MILLER_X) { // error - must not follow after X Uart14aReset(); } else { Uart.bitCount++; Uart.shiftReg = (Uart.shiftReg >> 1); // add a 0 to the shiftreg Uart.state = STATE_14A_MILLER_Z; Uart.endTime = Uart.startTime + 8 * (9 * Uart.len + Uart.bitCount + 1) - 6; if (Uart.bitCount >= 9) { // if we decoded a full byte (including parity) Uart.output[Uart.len++] = (Uart.shiftReg & 0xff); Uart.parityBits <<= 1; // make room for the parity bit Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); // store parity bit Uart.bitCount = 0; Uart.shiftReg = 0; if ((Uart.len & 0x0007) == 0) { // every 8 data bytes Uart.parity[Uart.parityLen++] = Uart.parityBits; // store 8 parity bits Uart.parityBits = 0; } } } } } else { if (IsMillerModulationNibble2(Uart.fourBits >> Uart.syncBit)) { // Modulation second half = Sequence X = logic "1" Uart.bitCount++; Uart.shiftReg = (Uart.shiftReg >> 1) | 0x100; // add a 1 to the shiftreg Uart.state = STATE_14A_MILLER_X; Uart.endTime = Uart.startTime + 8 * (9 * Uart.len + Uart.bitCount + 1) - 2; if (Uart.bitCount >= 9) { // if we decoded a full byte (including parity) Uart.output[Uart.len++] = (Uart.shiftReg & 0xff); Uart.parityBits <<= 1; // make room for the new parity bit Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); // store parity bit Uart.bitCount = 0; Uart.shiftReg = 0; if ((Uart.len & 0x0007) == 0) { // every 8 data bytes Uart.parity[Uart.parityLen++] = Uart.parityBits; // store 8 parity bits Uart.parityBits = 0; } } } else { // no modulation in both halves - Sequence Y if (Uart.state == STATE_14A_MILLER_Z || Uart.state == STATE_14A_MILLER_Y) { // Y after logic "0" - End of Communication Uart.state = STATE_14A_UNSYNCD; Uart.bitCount--; // last "0" was part of EOC sequence Uart.shiftReg <<= 1; // drop it if (Uart.bitCount > 0) { // if we decoded some bits Uart.shiftReg >>= (9 - Uart.bitCount); // right align them Uart.output[Uart.len++] = (Uart.shiftReg & 0xff); // add last byte to the output Uart.parityBits <<= 1; // add a (void) parity bit Uart.parityBits <<= (8 - (Uart.len & 0x0007)); // left align parity bits Uart.parity[Uart.parityLen++] = Uart.parityBits; // and store it return true; } else if (Uart.len & 0x0007) { // there are some parity bits to store Uart.parityBits <<= (8 - (Uart.len & 0x0007)); // left align remaining parity bits Uart.parity[Uart.parityLen++] = Uart.parityBits; // and store them } if (Uart.len) { return true; // we are finished with decoding the raw data sequence } else { Uart14aReset(); // Nothing received - start over } } if (Uart.state == STATE_14A_START_OF_COMMUNICATION) { // error - must not follow directly after SOC Uart14aReset(); } else { // a logic "0" Uart.bitCount++; Uart.shiftReg = (Uart.shiftReg >> 1); // add a 0 to the shiftreg Uart.state = STATE_14A_MILLER_Y; if (Uart.bitCount >= 9) { // if we decoded a full byte (including parity) Uart.output[Uart.len++] = (Uart.shiftReg & 0xff); Uart.parityBits <<= 1; // make room for the parity bit Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); // store parity bit Uart.bitCount = 0; Uart.shiftReg = 0; if ((Uart.len & 0x0007) == 0) { // every 8 data bytes Uart.parity[Uart.parityLen++] = Uart.parityBits; // store 8 parity bits Uart.parityBits = 0; } } } } } } return false; // not finished yet, need more data } //============================================================================= // ISO 14443 Type A - Manchester decoder //============================================================================= // Basics: // This decoder is used when the PM3 acts as a reader. // The tag will modulate the reader field by asserting different loads to it. As a consequence, the voltage // at the reader antenna will be modulated as well. The FPGA detects the modulation for us and would deliver e.g. the following: // ........ 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 ....... // The Manchester decoder needs to identify the following sequences: // 4 ticks modulated followed by 4 ticks unmodulated: Sequence D = 1 (also used as "start of communication") // 4 ticks unmodulated followed by 4 ticks modulated: Sequence E = 0 // 8 ticks unmodulated: Sequence F = end of communication // 8 ticks modulated: A collision. Save the collision position and treat as Sequence D // Note 1: the bitstream may start at any time. We therefore need to sync. // Note 2: parameter offset is used to determine the position of the parity bits (required for the anticollision command only) tDemod14a Demod; // Lookup-Table to decide if 4 raw bits are a modulation. // We accept three or four "1" in any position const bool Mod_Manchester_LUT[] = { false, false, false, false, false, false, false, true, false, false, false, true, false, true, true, true }; #define IsManchesterModulationNibble1(b) (Mod_Manchester_LUT[(b & 0x00F0) >> 4]) #define IsManchesterModulationNibble2(b) (Mod_Manchester_LUT[(b & 0x000F)]) tDemod14a *GetDemod14a() { return &Demod; } void Demod14aReset(void) { Demod.state = DEMOD_14A_UNSYNCD; Demod.len = 0; // number of decoded data bytes Demod.parityLen = 0; Demod.shiftReg = 0; // shiftreg to hold decoded data bits Demod.parityBits = 0; // Demod.collisionPos = 0; // Position of collision bit Demod.twoBits = 0xFFFF; // buffer for 2 Bits Demod.highCnt = 0; Demod.startTime = 0; Demod.endTime = 0; Demod.bitCount = 0; Demod.syncBit = 0xFFFF; Demod.samples = 0; } void Demod14aInit(uint8_t *data, uint8_t *par) { Demod.output = data; Demod.parity = par; Demod14aReset(); } // use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time RAMFUNC int ManchesterDecoding(uint8_t bit, uint16_t offset, uint32_t non_real_time) { Demod.twoBits = (Demod.twoBits << 8) | bit; if (Demod.state == DEMOD_14A_UNSYNCD) { if (Demod.highCnt < 2) { // wait for a stable unmodulated signal if (Demod.twoBits == 0x0000) { Demod.highCnt++; } else { Demod.highCnt = 0; } } else { Demod.syncBit = 0xFFFF; // not set if ((Demod.twoBits & 0x7700) == 0x7000) Demod.syncBit = 7; else if ((Demod.twoBits & 0x3B80) == 0x3800) Demod.syncBit = 6; else if ((Demod.twoBits & 0x1DC0) == 0x1C00) Demod.syncBit = 5; else if ((Demod.twoBits & 0x0EE0) == 0x0E00) Demod.syncBit = 4; else if ((Demod.twoBits & 0x0770) == 0x0700) Demod.syncBit = 3; else if ((Demod.twoBits & 0x03B8) == 0x0380) Demod.syncBit = 2; else if ((Demod.twoBits & 0x01DC) == 0x01C0) Demod.syncBit = 1; else if ((Demod.twoBits & 0x00EE) == 0x00E0) Demod.syncBit = 0; if (Demod.syncBit != 0xFFFF) { Demod.startTime = non_real_time ? non_real_time : (GetCountSspClk() & 0xfffffff8); Demod.startTime -= Demod.syncBit; Demod.bitCount = offset; // number of decoded data bits Demod.state = DEMOD_14A_MANCHESTER_DATA; } } } else { if (IsManchesterModulationNibble1(Demod.twoBits >> Demod.syncBit)) { // modulation in first half if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) { // ... and in second half = collision if (!Demod.collisionPos) { Demod.collisionPos = (Demod.len << 3) + Demod.bitCount; } } // modulation in first half only - Sequence D = 1 Demod.bitCount++; Demod.shiftReg = (Demod.shiftReg >> 1) | 0x100; // in both cases, add a 1 to the shiftreg if (Demod.bitCount == 9) { // if we decoded a full byte (including parity) Demod.output[Demod.len++] = (Demod.shiftReg & 0xff); Demod.parityBits <<= 1; // make room for the parity bit Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); // store parity bit Demod.bitCount = 0; Demod.shiftReg = 0; if ((Demod.len & 0x0007) == 0) { // every 8 data bytes Demod.parity[Demod.parityLen++] = Demod.parityBits; // store 8 parity bits Demod.parityBits = 0; } } Demod.endTime = Demod.startTime + 8 * (9 * Demod.len + Demod.bitCount + 1) - 4; } else { // no modulation in first half if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) { // and modulation in second half = Sequence E = 0 Demod.bitCount++; Demod.shiftReg = (Demod.shiftReg >> 1); // add a 0 to the shiftreg if (Demod.bitCount >= 9) { // if we decoded a full byte (including parity) Demod.output[Demod.len++] = (Demod.shiftReg & 0xff); Demod.parityBits <<= 1; // make room for the new parity bit Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); // store parity bit Demod.bitCount = 0; Demod.shiftReg = 0; if ((Demod.len & 0x0007) == 0) { // every 8 data bytes Demod.parity[Demod.parityLen++] = Demod.parityBits; // store 8 parity bits1 Demod.parityBits = 0; } } Demod.endTime = Demod.startTime + 8 * (9 * Demod.len + Demod.bitCount + 1); } else { // no modulation in both halves - End of communication if (Demod.bitCount > 0) { // there are some remaining data bits Demod.shiftReg >>= (9 - Demod.bitCount); // right align the decoded bits Demod.output[Demod.len++] = Demod.shiftReg & 0xff; // and add them to the output Demod.parityBits <<= 1; // add a (void) parity bit Demod.parityBits <<= (8 - (Demod.len & 0x0007)); // left align remaining parity bits Demod.parity[Demod.parityLen++] = Demod.parityBits; // and store them return true; } else if (Demod.len & 0x0007) { // there are some parity bits to store Demod.parityBits <<= (8 - (Demod.len & 0x0007)); // left align remaining parity bits Demod.parity[Demod.parityLen++] = Demod.parityBits; // and store them } if (Demod.len) { return true; // we are finished with decoding the raw data sequence } else { // nothing received. Start over Demod14aReset(); } } } } return false; // not finished yet, need more data } // Thinfilm, Kovio mangels ISO14443A in the way that they don't use start bit nor parity bits. RAMFUNC int ManchesterDecoding_Thinfilm(uint8_t bit) { Demod.twoBits = (Demod.twoBits << 8) | bit; if (Demod.state == DEMOD_14A_UNSYNCD) { if (Demod.highCnt < 2) { // wait for a stable unmodulated signal if (Demod.twoBits == 0x0000) { Demod.highCnt++; } else { Demod.highCnt = 0; } } else { Demod.syncBit = 0xFFFF; // not set if ((Demod.twoBits & 0x7700) == 0x7000) Demod.syncBit = 7; else if ((Demod.twoBits & 0x3B80) == 0x3800) Demod.syncBit = 6; else if ((Demod.twoBits & 0x1DC0) == 0x1C00) Demod.syncBit = 5; else if ((Demod.twoBits & 0x0EE0) == 0x0E00) Demod.syncBit = 4; else if ((Demod.twoBits & 0x0770) == 0x0700) Demod.syncBit = 3; else if ((Demod.twoBits & 0x03B8) == 0x0380) Demod.syncBit = 2; else if ((Demod.twoBits & 0x01DC) == 0x01C0) Demod.syncBit = 1; else if ((Demod.twoBits & 0x00EE) == 0x00E0) Demod.syncBit = 0; if (Demod.syncBit != 0xFFFF) { Demod.startTime = (GetCountSspClk() & 0xfffffff8); Demod.startTime -= Demod.syncBit; Demod.bitCount = 1; // number of decoded data bits Demod.shiftReg = 1; Demod.state = DEMOD_14A_MANCHESTER_DATA; } } } else { if (IsManchesterModulationNibble1(Demod.twoBits >> Demod.syncBit)) { // modulation in first half if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) { // ... and in second half = collision if (!Demod.collisionPos) { Demod.collisionPos = (Demod.len << 3) + Demod.bitCount; } } // modulation in first half only - Sequence D = 1 Demod.bitCount++; Demod.shiftReg = (Demod.shiftReg << 1) | 0x1; // in both cases, add a 1 to the shiftreg if (Demod.bitCount == 8) { // if we decoded a full byte Demod.output[Demod.len++] = (Demod.shiftReg & 0xff); Demod.bitCount = 0; Demod.shiftReg = 0; } Demod.endTime = Demod.startTime + 8 * (8 * Demod.len + Demod.bitCount + 1) - 4; } else { // no modulation in first half if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) { // and modulation in second half = Sequence E = 0 Demod.bitCount++; Demod.shiftReg = (Demod.shiftReg << 1); // add a 0 to the shiftreg if (Demod.bitCount >= 8) { // if we decoded a full byte Demod.output[Demod.len++] = (Demod.shiftReg & 0xff); Demod.bitCount = 0; Demod.shiftReg = 0; } Demod.endTime = Demod.startTime + 8 * (8 * Demod.len + Demod.bitCount + 1); } else { // no modulation in both halves - End of communication if (Demod.bitCount > 0) { // there are some remaining data bits Demod.shiftReg <<= (8 - Demod.bitCount); // left align the decoded bits Demod.output[Demod.len++] = Demod.shiftReg & 0xff; // and add them to the output return true; } if (Demod.len) { return true; // we are finished with decoding the raw data sequence } else { // nothing received. Start over Demod14aReset(); } } } } return false; // not finished yet, need more data } //============================================================================= // Finally, a `sniffer' for ISO 14443 Type A // Both sides of communication! //============================================================================= //----------------------------------------------------------------------------- // Record the sequence of commands sent by the reader to the tag, with // triggering so that we start recording at the point that the tag is moved // near the reader. // "hf 14a sniff" //----------------------------------------------------------------------------- void RAMFUNC SniffIso14443a(uint8_t param) { LEDsoff(); // param: // bit 0 - trigger from first card answer // bit 1 - trigger from first reader 7-bit request iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER); // Allocate memory from BigBuf for some buffers // free all previous allocations first BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); set_tracing(true); // The command (reader -> tag) that we're receiving. uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE); uint8_t *receivedCmdPar = BigBuf_malloc(MAX_PARITY_SIZE); // The response (tag -> reader) that we're receiving. uint8_t *receivedResp = BigBuf_malloc(MAX_FRAME_SIZE); uint8_t *receivedRespPar = BigBuf_malloc(MAX_PARITY_SIZE); // The DMA buffer, used to stream samples from the FPGA uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE); uint8_t *data = dmaBuf; uint8_t previous_data = 0; int maxDataLen = 0, dataLen; bool TagIsActive = false; bool ReaderIsActive = false; // Set up the demodulator for tag -> reader responses. Demod14aInit(receivedResp, receivedRespPar); // Set up the demodulator for the reader -> tag commands Uart14aInit(receivedCmd, receivedCmdPar); DbpString("Starting to sniff"); // Setup and start DMA. if (!FpgaSetupSscDma((uint8_t *) dmaBuf, DMA_BUFFER_SIZE)) { if (DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting"); return; } // We won't start recording the frames that we acquire until we trigger; // a good trigger condition to get started is probably when we see a // response from the tag. // triggered == false -- to wait first for card bool triggered = !(param & 0x03); uint32_t rx_samples = 0; // loop and listen while (!BUTTON_PRESS()) { WDT_HIT(); LED_A_ON(); int register readBufDataP = data - dmaBuf; int register dmaBufDataP = DMA_BUFFER_SIZE - AT91C_BASE_PDC_SSC->PDC_RCR; if (readBufDataP <= dmaBufDataP) dataLen = dmaBufDataP - readBufDataP; else dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP; // test for length of buffer if (dataLen > maxDataLen) { maxDataLen = dataLen; if (dataLen > (9 * DMA_BUFFER_SIZE / 10)) { Dbprintf("[!] blew circular buffer! | datalen %u", dataLen); break; } } if (dataLen < 1) continue; // primary buffer was stopped( <-- we lost data! if (!AT91C_BASE_PDC_SSC->PDC_RCR) { AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) dmaBuf; AT91C_BASE_PDC_SSC->PDC_RCR = DMA_BUFFER_SIZE; Dbprintf("[-] RxEmpty ERROR | data length %d", dataLen); // temporary } // secondary buffer sets as primary, secondary buffer was stopped if (!AT91C_BASE_PDC_SSC->PDC_RNCR) { AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf; AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE; } LED_A_OFF(); // Need two samples to feed Miller and Manchester-Decoder if (rx_samples & 0x01) { if (!TagIsActive) { // no need to try decoding reader data if the tag is sending uint8_t readerdata = (previous_data & 0xF0) | (*data >> 4); if (MillerDecoding(readerdata, (rx_samples - 1) * 4)) { LED_C_ON(); // check - if there is a short 7bit request from reader if ((!triggered) && (param & 0x02) && (Uart.len == 1) && (Uart.bitCount == 7)) triggered = true; if (triggered) { if (!LogTrace(receivedCmd, Uart.len, Uart.startTime * 16 - DELAY_READER_AIR2ARM_AS_SNIFFER, Uart.endTime * 16 - DELAY_READER_AIR2ARM_AS_SNIFFER, Uart.parity, true)) break; } /* ready to receive another command. */ Uart14aReset(); /* reset the demod code, which might have been */ /* false-triggered by the commands from the reader. */ Demod14aReset(); LED_B_OFF(); } ReaderIsActive = (Uart.state != STATE_14A_UNSYNCD); } // no need to try decoding tag data if the reader is sending - and we cannot afford the time if (!ReaderIsActive) { uint8_t tagdata = (previous_data << 4) | (*data & 0x0F); if (ManchesterDecoding(tagdata, 0, (rx_samples - 1) * 4)) { LED_B_ON(); if (!LogTrace(receivedResp, Demod.len, Demod.startTime * 16 - DELAY_TAG_AIR2ARM_AS_SNIFFER, Demod.endTime * 16 - DELAY_TAG_AIR2ARM_AS_SNIFFER, Demod.parity, false)) break; if ((!triggered) && (param & 0x01)) triggered = true; // ready to receive another response. Demod14aReset(); // reset the Miller decoder including its (now outdated) input buffer Uart14aReset(); //Uart14aInit(receivedCmd, receivedCmdPar); LED_C_OFF(); } TagIsActive = (Demod.state != DEMOD_14A_UNSYNCD); } } previous_data = *data; rx_samples++; data++; if (data == dmaBuf + DMA_BUFFER_SIZE) { data = dmaBuf; } } // end main loop if (DBGLEVEL >= DBG_ERROR) { Dbprintf("maxDataLen=%d, Uart.state=%x, Uart.len=%d", maxDataLen, Uart.state, Uart.len); Dbprintf("traceLen=" _YELLOW_("%d")", Uart.output[0]="_YELLOW_("%08x"), BigBuf_get_traceLen(), (uint32_t)Uart.output[0]); } switch_off(); } //----------------------------------------------------------------------------- // Prepare tag messages //----------------------------------------------------------------------------- static void CodeIso14443aAsTagPar(const uint8_t *cmd, uint16_t len, uint8_t *par, bool collision) { //uint8_t localCol = 0; ToSendReset(); // Correction bit, might be removed when not needed ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(1); // <----- ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); // Send startbit ToSend[++ToSendMax] = SEC_D; LastProxToAirDuration = 8 * ToSendMax - 4; for (uint16_t i = 0; i < len; i++) { uint8_t b = cmd[i]; // Data bits for (uint16_t j = 0; j < 8; j++) { //if (collision && (localCol >= colpos)){ if (collision) { ToSend[++ToSendMax] = SEC_COLL; //localCol++; } else { if (b & 1) { ToSend[++ToSendMax] = SEC_D; } else { ToSend[++ToSendMax] = SEC_E; } b >>= 1; } } if (collision) { ToSend[++ToSendMax] = SEC_COLL; LastProxToAirDuration = 8 * ToSendMax; } else { // Get the parity bit if (par[i >> 3] & (0x80 >> (i & 0x0007))) { ToSend[++ToSendMax] = SEC_D; LastProxToAirDuration = 8 * ToSendMax - 4; } else { ToSend[++ToSendMax] = SEC_E; LastProxToAirDuration = 8 * ToSendMax; } } } // Send stopbit ToSend[++ToSendMax] = SEC_F; // Convert from last byte pos to length ToSendMax++; } static void CodeIso14443aAsTagEx(const uint8_t *cmd, uint16_t len, bool collision) { uint8_t par[MAX_PARITY_SIZE] = {0}; GetParity(cmd, len, par); CodeIso14443aAsTagPar(cmd, len, par, collision); } static void CodeIso14443aAsTag(const uint8_t *cmd, uint16_t len) { CodeIso14443aAsTagEx(cmd, len, false); } static void Code4bitAnswerAsTag(uint8_t cmd) { uint8_t b = cmd; ToSendReset(); // Correction bit, might be removed when not needed ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(1); // 1 ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); // Send startbit ToSend[++ToSendMax] = SEC_D; for (uint8_t i = 0; i < 4; i++) { if (b & 1) { ToSend[++ToSendMax] = SEC_D; LastProxToAirDuration = 8 * ToSendMax - 4; } else { ToSend[++ToSendMax] = SEC_E; LastProxToAirDuration = 8 * ToSendMax; } b >>= 1; } // Send stopbit ToSend[++ToSendMax] = SEC_F; // Convert from last byte pos to length ToSendMax++; } //----------------------------------------------------------------------------- // Wait for commands from reader // stop when button is pressed or client usb connection resets // or return TRUE when command is captured //----------------------------------------------------------------------------- static bool GetIso14443aCommandFromReader(uint8_t *received, uint8_t *par, int *len) { // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen // only, since we are receiving, not transmitting). // Signal field is off with the appropriate LED LED_D_OFF(); FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN); // Now run a `software UART` on the stream of incoming samples. Uart14aInit(received, par); // clear RXRDY: uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR; (void)b; uint16_t check = 0; for (;;) { if (check == 1000) { if (BUTTON_PRESS() || data_available()) return false; check = 0; } ++check; WDT_HIT(); if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { b = (uint8_t)AT91C_BASE_SSC->SSC_RHR; if (MillerDecoding(b, 0)) { *len = Uart.len; return true; } } } return false; } static bool prepare_tag_modulation(tag_response_info_t *response_info, size_t max_buffer_size) { // Example response, answer to MIFARE Classic read block will be 16 bytes + 2 CRC = 18 bytes // This will need the following byte array for a modulation sequence // 144 data bits (18 * 8) // 18 parity bits // 2 Start and stop // 1 Correction bit (Answer in 1172 or 1236 periods, see FPGA) // 1 just for the case // ----------- + // 166 bytes, since every bit that needs to be send costs us a byte // // Prepare the tag modulation bits from the message CodeIso14443aAsTag(response_info->response, response_info->response_n); // Make sure we do not exceed the free buffer space if (ToSendMax > max_buffer_size) { Dbprintf("Out of memory, when modulating bits for tag answer:"); Dbhexdump(response_info->response_n, response_info->response, false); return false; } // Copy the byte array, used for this modulation to the buffer position memcpy(response_info->modulation, ToSend, ToSendMax); // Store the number of bytes that were used for encoding/modulation and the time needed to transfer them response_info->modulation_n = ToSendMax; response_info->ProxToAirDuration = LastProxToAirDuration; return true; } bool prepare_allocated_tag_modulation(tag_response_info_t *response_info, uint8_t **buffer, size_t *max_buffer_size) { // Retrieve and store the current buffer index response_info->modulation = *buffer; // Forward the prepare tag modulation function to the inner function if (prepare_tag_modulation(response_info, *max_buffer_size)) { // Update the free buffer offset and the remaining buffer size *buffer += ToSendMax; *max_buffer_size -= ToSendMax; return true; } else { return false; } } static bool SimulateIso14443aInit(int tagType, int flags, uint8_t *data, tag_response_info_t **responses, uint32_t *cuid, uint32_t counters[3], uint8_t tearings[3], uint8_t *pages) { uint8_t sak = 0; // The first response contains the ATQA (note: bytes are transmitted in reverse order). static uint8_t rATQA[2] = { 0x00 }; // The second response contains the (mandatory) first 24 bits of the UID static uint8_t rUIDc1[5] = { 0x00 }; // For UID size 7, static uint8_t rUIDc2[5] = { 0x00 }; // Prepare the mandatory SAK (for 4 and 7 byte UID) static uint8_t rSAKc1[3] = { 0x00 }; // Prepare the optional second SAK (for 7 byte UID), drop the cascade bit static uint8_t rSAKc2[3] = { 0x00 }; // dummy ATS (pseudo-ATR), answer to RATS static uint8_t rRATS[] = { 0x04, 0x58, 0x80, 0x02, 0x00, 0x00 }; // GET_VERSION response for EV1/NTAG static uint8_t rVERSION[10] = { 0x00 }; // READ_SIG response for EV1/NTAG static uint8_t rSIGN[34] = { 0x00 }; switch (tagType) { case 1: { // MIFARE Classic 1k rATQA[0] = 0x04; sak = 0x08; } break; case 2: { // MIFARE Ultralight rATQA[0] = 0x44; sak = 0x00; // some first pages of UL/NTAG dump is special data mfu_dump_t *mfu_header = (mfu_dump_t *) BigBuf_get_EM_addr(); *pages = MAX(mfu_header->pages, 15); } break; case 3: { // MIFARE DESFire rATQA[0] = 0x04; rATQA[1] = 0x03; sak = 0x20; } break; case 4: { // ISO/IEC 14443-4 - javacard (JCOP) rATQA[0] = 0x04; sak = 0x28; } break; case 5: { // MIFARE TNP3XXX rATQA[0] = 0x01; rATQA[1] = 0x0f; sak = 0x01; } break; case 6: { // MIFARE Mini 320b rATQA[0] = 0x44; sak = 0x09; } break; case 7: { // NTAG rATQA[0] = 0x44; sak = 0x00; // some first pages of UL/NTAG dump is special data mfu_dump_t *mfu_header = (mfu_dump_t *) BigBuf_get_EM_addr(); *pages = MAX(mfu_header->pages, 19); // counters and tearing flags for (int i = 0; i < 3; i++) { counters[i] = le24toh(mfu_header->counter_tearing[i]); tearings[i] = mfu_header->counter_tearing[i][3]; } // GET_VERSION memcpy(rVERSION, mfu_header->version, 8); AddCrc14A(rVERSION, sizeof(rVERSION) - 2); // READ_SIG memcpy(rSIGN, mfu_header->signature, 32); AddCrc14A(rSIGN, sizeof(rSIGN) - 2); } break; case 8: { // MIFARE Classic 4k rATQA[0] = 0x02; sak = 0x18; } break; case 9 : { // FM11RF005SH (Shanghai Metro) rATQA[0] = 0x03; rATQA[1] = 0x00; sak = 0x0A; } break; default: { if (DBGLEVEL >= DBG_ERROR) Dbprintf("Error: unknown tagtype (%d)", tagType); return false; } break; } // if uid not supplied then get from emulator memory if (data[0] == 0 || (flags & FLAG_UID_IN_EMUL) == FLAG_UID_IN_EMUL) { if (tagType == 2 || tagType == 7) { uint16_t start = MFU_DUMP_PREFIX_LENGTH; uint8_t emdata[8]; emlGetMemBt(emdata, start, sizeof(emdata)); memcpy(data, emdata, 3); // uid bytes 0-2 memcpy(data + 3, emdata + 4, 4); // uid bytes 3-7 flags |= FLAG_7B_UID_IN_DATA; } else { emlGetMemBt(data, 0, 4); flags |= FLAG_4B_UID_IN_DATA; } } if ((flags & FLAG_7B_UID_IN_DATA) == FLAG_7B_UID_IN_DATA) { rUIDc1[0] = 0x88; // Cascade Tag marker rUIDc1[1] = data[0]; rUIDc1[2] = data[1]; rUIDc1[3] = data[2]; rUIDc2[0] = data[3]; rUIDc2[1] = data[4]; rUIDc2[2] = data[5]; rUIDc2[3] = data[6]; rUIDc2[4] = rUIDc2[0] ^ rUIDc2[1] ^ rUIDc2[2] ^ rUIDc2[3]; // Configure the ATQA and SAK accordingly rATQA[0] |= 0x40; sak |= 0x04; *cuid = bytes_to_num(data + 3, 4); } else if ((flags & FLAG_4B_UID_IN_DATA) == FLAG_4B_UID_IN_DATA) { memcpy(rUIDc1, data, 4); // Configure the ATQA and SAK accordingly rATQA[0] &= 0xBF; sak &= 0xFB; *cuid = bytes_to_num(data, 4); } else { if (DBGLEVEL >= DBG_ERROR) Dbprintf("[-] ERROR: UID size not defined"); return false; } // Calculate the BitCountCheck (BCC) for the first 4 bytes of the UID. rUIDc1[4] = rUIDc1[0] ^ rUIDc1[1] ^ rUIDc1[2] ^ rUIDc1[3]; rSAKc1[0] = sak; AddCrc14A(rSAKc1, sizeof(rSAKc1) - 2); rSAKc2[0] = sak & 0xFB; AddCrc14A(rSAKc2, sizeof(rSAKc2) - 2); // Format byte = 0x58: FSCI=0x08 (FSC=256), TA(1) and TC(1) present, // TA(1) = 0x80: different divisors not supported, DR = 1, DS = 1 // 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) // TC(1) = 0x02: CID supported, NAD not supported AddCrc14A(rRATS, sizeof(rRATS) - 2); #define TAG_RESPONSE_COUNT 8 static tag_response_info_t responses_init[TAG_RESPONSE_COUNT] = { { .response = rATQA, .response_n = sizeof(rATQA) }, // Answer to request - respond with card type { .response = rUIDc1, .response_n = sizeof(rUIDc1) }, // Anticollision cascade1 - respond with uid { .response = rUIDc2, .response_n = sizeof(rUIDc2) }, // Anticollision cascade2 - respond with 2nd half of uid if asked { .response = rSAKc1, .response_n = sizeof(rSAKc1) }, // Acknowledge select - cascade 1 { .response = rSAKc2, .response_n = sizeof(rSAKc2) }, // Acknowledge select - cascade 2 { .response = rRATS, .response_n = sizeof(rRATS) }, // dummy ATS (pseudo-ATR), answer to RATS { .response = rVERSION, .response_n = sizeof(rVERSION) }, // EV1/NTAG GET_VERSION response { .response = rSIGN, .response_n = sizeof(rSIGN) } // EV1/NTAG READ_SIG response }; // "precompile" responses. There are 8 predefined responses with a total of 68 bytes data to transmit. // Coded responses need one byte per bit to transfer (data, parity, start, stop, correction) // 68 * 8 data bits, 68 * 1 parity bits, 8 start bits, 8 stop bits, 8 correction bits -- 636 bytes buffer #define ALLOCATED_TAG_MODULATION_BUFFER_SIZE 636 uint8_t *free_buffer = BigBuf_malloc(ALLOCATED_TAG_MODULATION_BUFFER_SIZE); // modulation buffer pointer and current buffer free space size uint8_t *free_buffer_pointer = free_buffer; size_t free_buffer_size = ALLOCATED_TAG_MODULATION_BUFFER_SIZE; // Prepare the responses of the anticollision phase // there will be not enough time to do this at the moment the reader sends it REQA for (size_t i = 0; i < TAG_RESPONSE_COUNT; i++) { if (prepare_allocated_tag_modulation(&responses_init[i], &free_buffer_pointer, &free_buffer_size) == false) { BigBuf_free_keep_EM(); if (DBGLEVEL >= DBG_ERROR) Dbprintf("Not enough modulation buffer size, exit after %d elements", i); return false; } } *responses = responses_init; // indices into responses array: #define ATQA 0 #define UIDC1 1 #define UIDC2 2 #define SAKC1 3 #define SAKC2 4 #define RATS 5 #define VERSION 6 #define SIGNATURE 7 return true; } //----------------------------------------------------------------------------- // Main loop of simulated tag: receive commands from reader, decide what // response to send, and send it. // 'hf 14a sim' //----------------------------------------------------------------------------- void SimulateIso14443aTag(uint8_t tagType, uint8_t flags, uint8_t *data) { #define ATTACK_KEY_COUNT 8 // keep same as define in cmdhfmf.c -> readerAttack() tag_response_info_t *responses; uint32_t cuid = 0; uint32_t nonce = 0; uint32_t counters[3] = { 0x00, 0x00, 0x00 }; uint8_t tearings[3] = { 0xbd, 0xbd, 0xbd }; uint8_t pages = 0; // Here, we collect CUID, block1, keytype1, NT1, NR1, AR1, CUID, block2, keytyp2, NT2, NR2, AR2 // it should also collect block, keytype. uint8_t cardAUTHSC = 0; uint8_t cardAUTHKEY = 0xff; // no authentication // allow collecting up to 8 sets of nonces to allow recovery of up to 8 keys nonces_t ar_nr_nonces[ATTACK_KEY_COUNT]; // for attack types moebius memset(ar_nr_nonces, 0x00, sizeof(ar_nr_nonces)); uint8_t moebius_count = 0; // command buffers uint8_t receivedCmd[MAX_FRAME_SIZE] = { 0x00 }; uint8_t receivedCmdPar[MAX_PARITY_SIZE] = { 0x00 }; // Allocate 512 bytes for the dynamic modulation, created when the reader queries for it // Such a response is less time critical, so we can prepare them on the fly #define DYNAMIC_RESPONSE_BUFFER_SIZE 64 #define DYNAMIC_MODULATION_BUFFER_SIZE 512 uint8_t dynamic_response_buffer[DYNAMIC_RESPONSE_BUFFER_SIZE]; uint8_t dynamic_modulation_buffer[DYNAMIC_MODULATION_BUFFER_SIZE]; tag_response_info_t dynamic_response_info = { .response = dynamic_response_buffer, .response_n = 0, .modulation = dynamic_modulation_buffer, .modulation_n = 0 }; // free eventually allocated BigBuf memory but keep Emulator Memory BigBuf_free_keep_EM(); if (SimulateIso14443aInit(tagType, flags, data, &responses, &cuid, counters, tearings, &pages) == false) { BigBuf_free_keep_EM(); reply_ng(CMD_HF_MIFARE_SIMULATE, PM3_EINIT, NULL, 0); return; } // We need to listen to the high-frequency, peak-detected path. iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN); int len = 0; // To control where we are in the protocol #define ORDER_NONE 0 #define ORDER_REQA 1 #define ORDER_SELECT_ALL_CL1 2 #define ORDER_SELECT_CL1 3 #define ORDER_HALTED 5 #define ORDER_WUPA 6 #define ORDER_AUTH 7 #define ORDER_SELECT_ALL_CL2 20 #define ORDER_SELECT_CL2 30 #define ORDER_EV1_COMP_WRITE 40 #define ORDER_RATS 70 uint8_t order = ORDER_NONE; int retval = PM3_SUCCESS; // Just to allow some checks int happened = 0; int happened2 = 0; int cmdsRecvd = 0; // compatible write block number uint8_t wrblock = 0; clear_trace(); set_tracing(true); LED_A_ON(); for (;;) { WDT_HIT(); // Clean receive command buffer if (!GetIso14443aCommandFromReader(receivedCmd, receivedCmdPar, &len)) { Dbprintf("Emulator stopped. Trace length: %d ", BigBuf_get_traceLen()); retval = PM3_EOPABORTED; break; } tag_response_info_t *p_response = NULL; // Okay, look at the command now. int lastorder = order; // // we need to check "ordered" states before, because received data may be same to any command - is wrong!!! // if (order == ORDER_EV1_COMP_WRITE && len == 18) { // MIFARE_ULC_COMP_WRITE part 2 // 16 bytes data + 2 bytes crc, only least significant 4 bytes are written bool isCrcCorrect = CheckCrc14A(receivedCmd, len); if (isCrcCorrect) { // first blocks of emu are header emlSetMem_xt(receivedCmd, wrblock + MFU_DUMP_PREFIX_LENGTH / 4, 1, 4); // send ACK EmSend4bit(CARD_ACK); } else { // send NACK 0x1 == crc/parity error EmSend4bit(CARD_NACK_PA); } order = ORDER_NONE; // back to work state p_response = NULL; } else if (order == ORDER_AUTH && len == 8) { // Received {nr] and {ar} (part of authentication) LogTrace(receivedCmd, Uart.len, Uart.startTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, true); uint32_t nr = bytes_to_num(receivedCmd, 4); uint32_t ar = bytes_to_num(receivedCmd + 4, 4); // Collect AR/NR per keytype & sector if ((flags & FLAG_NR_AR_ATTACK) == FLAG_NR_AR_ATTACK) { int8_t index = -1; int8_t empty = -1; for (uint8_t i = 0; i < ATTACK_KEY_COUNT; i++) { // find which index to use if ((cardAUTHSC == ar_nr_nonces[i].sector) && (cardAUTHKEY == ar_nr_nonces[i].keytype)) index = i; // keep track of empty slots. if (ar_nr_nonces[i].state == EMPTY) empty = i; } // if no empty slots. Choose first and overwrite. if (index == -1) { if (empty == -1) { index = 0; ar_nr_nonces[index].state = EMPTY; } else { index = empty; } } switch (ar_nr_nonces[index].state) { case EMPTY: { // first nonce collect ar_nr_nonces[index].cuid = cuid; ar_nr_nonces[index].sector = cardAUTHSC; ar_nr_nonces[index].keytype = cardAUTHKEY; ar_nr_nonces[index].nonce = nonce; ar_nr_nonces[index].nr = nr; ar_nr_nonces[index].ar = ar; ar_nr_nonces[index].state = FIRST; break; } case FIRST : { // second nonce collect ar_nr_nonces[index].nonce2 = nonce; ar_nr_nonces[index].nr2 = nr; ar_nr_nonces[index].ar2 = ar; ar_nr_nonces[index].state = SECOND; // send to client (one struct nonces_t) reply_ng(CMD_HF_MIFARE_SIMULATE, PM3_SUCCESS, (uint8_t *)&ar_nr_nonces[index], sizeof(nonces_t)); ar_nr_nonces[index].state = EMPTY; ar_nr_nonces[index].sector = 0; ar_nr_nonces[index].keytype = 0; moebius_count++; break; } default: break; } } order = ORDER_NONE; // back to work state p_response = NULL; // // now check commands in received buffer // } else if (receivedCmd[0] == ISO14443A_CMD_REQA && len == 1) { // Received a REQUEST p_response = &responses[ATQA]; order = ORDER_REQA; } else if (receivedCmd[0] == ISO14443A_CMD_WUPA && len == 1) { // Received a WAKEUP p_response = &responses[ATQA]; order = ORDER_WUPA; } else if (receivedCmd[1] == 0x20 && receivedCmd[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT && len == 2) { // Received request for UID (cascade 1) p_response = &responses[UIDC1]; order = ORDER_SELECT_ALL_CL1; } else if (receivedCmd[1] == 0x20 && receivedCmd[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT_2 && len == 2) { // Received request for UID (cascade 2) p_response = &responses[UIDC2]; order = ORDER_SELECT_ALL_CL2; } else if (receivedCmd[1] == 0x70 && receivedCmd[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT && len == 9) { // Received a SELECT (cascade 1) p_response = &responses[SAKC1]; order = ORDER_SELECT_CL1; } else if (receivedCmd[1] == 0x70 && receivedCmd[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT_2 && len == 9) { // Received a SELECT (cascade 2) p_response = &responses[SAKC2]; order = ORDER_SELECT_CL2; } else if (receivedCmd[0] == ISO14443A_CMD_READBLOCK && len == 4) { // Received a (plain) READ uint8_t block = receivedCmd[1]; // if Ultralight or NTAG (4 byte blocks) if (tagType == 7 || tagType == 2) { if (block > pages) { // send NACK 0x0 == invalid argument EmSend4bit(CARD_NACK_IV); } else { // first blocks of emu are header uint16_t start = block * 4 + MFU_DUMP_PREFIX_LENGTH; uint8_t emdata[MAX_MIFARE_FRAME_SIZE]; emlGetMemBt(emdata, start, 16); AddCrc14A(emdata, 16); EmSendCmd(emdata, sizeof(emdata)); } // We already responded, do not send anything with the EmSendCmd14443aRaw() that is called below p_response = NULL; } else if (tagType == 9 && block == 1) { // FM11005SH. 16blocks, 4bytes / block. // block0 = 2byte Customer ID (CID), 2byte Manufacture ID (MID) // block1 = 4byte UID. p_response = &responses[UIDC1]; } else { // all other tags (16 byte block tags) uint8_t emdata[MAX_MIFARE_FRAME_SIZE]; emlGetMemBt(emdata, block, 16); AddCrc14A(emdata, 16); EmSendCmd(emdata, sizeof(emdata)); // EmSendCmd(data+(4*receivedCmd[1]),16); // Dbprintf("Read request from reader: %x %x",receivedCmd[0],receivedCmd[1]); // We already responded, do not send anything with the EmSendCmd14443aRaw() that is called below p_response = NULL; } } else if (receivedCmd[0] == MIFARE_ULEV1_FASTREAD && len == 5) { // Received a FAST READ (ranged read) uint8_t block1 = receivedCmd[1]; uint8_t block2 = receivedCmd[2]; if (block1 > pages) { // send NACK 0x0 == invalid argument EmSend4bit(CARD_NACK_IV); } else { uint8_t emdata[MAX_FRAME_SIZE]; // first blocks of emu are header int start = block1 * 4 + MFU_DUMP_PREFIX_LENGTH; len = (block2 - block1 + 1) * 4; emlGetMemBt(emdata, start, len); AddCrc14A(emdata, len); EmSendCmd(emdata, len + 2); } p_response = NULL; } else if (receivedCmd[0] == MIFARE_ULC_WRITE && len == 8 && (tagType == 2 || tagType == 7)) { // Received a WRITE // cmd + block + 4 bytes data + 2 bytes crc bool isCrcCorrect = CheckCrc14A(receivedCmd, len); if (isCrcCorrect) { uint8_t block = receivedCmd[1]; if (block > pages) { // send NACK 0x0 == invalid argument EmSend4bit(CARD_NACK_IV); } else { // first blocks of emu are header emlSetMem_xt(&receivedCmd[2], block + MFU_DUMP_PREFIX_LENGTH / 4, 1, 4); // send ACK EmSend4bit(CARD_ACK); } } else { // send NACK 0x1 == crc/parity error EmSend4bit(CARD_NACK_PA); } p_response = NULL; } else if (receivedCmd[0] == MIFARE_ULC_COMP_WRITE && len == 4 && (tagType == 2 || tagType == 7)) { // cmd + block + 2 bytes crc bool isCrcCorrect = CheckCrc14A(receivedCmd, len); if (isCrcCorrect) { wrblock = receivedCmd[1]; if (wrblock > pages) { // send NACK 0x0 == invalid argument EmSend4bit(CARD_NACK_IV); } else { // send ACK EmSend4bit(CARD_ACK); // go to part 2 order = ORDER_EV1_COMP_WRITE; } } else { // send NACK 0x1 == crc/parity error EmSend4bit(CARD_NACK_PA); } p_response = NULL; } else if (receivedCmd[0] == MIFARE_ULEV1_READSIG && len == 4 && tagType == 7) { // Received a READ SIGNATURE -- p_response = &responses[SIGNATURE]; } else if (receivedCmd[0] == MIFARE_ULEV1_READ_CNT && len == 4 && tagType == 7) { // Received a READ COUNTER -- uint8_t index = receivedCmd[1]; if (index > 2) { // send NACK 0x0 == invalid argument EmSend4bit(CARD_NACK_IV); } else { uint8_t cmd[] = {0x00, 0x00, 0x00, 0x14, 0xa5}; htole24(counters[index], cmd); AddCrc14A(cmd, sizeof(cmd) - 2); EmSendCmd(cmd, sizeof(cmd)); } p_response = NULL; } else if (receivedCmd[0] == MIFARE_ULEV1_INCR_CNT && len == 8 && tagType == 7) { // Received a INC COUNTER -- uint8_t index = receivedCmd[1]; if (index > 2) { // send NACK 0x0 == invalid argument EmSend4bit(CARD_NACK_IV); } else { uint32_t val = le24toh(receivedCmd + 2) + counters[index]; // if new value + old value is bigger 24bits, fail if (val > 0xFFFFFF) { // send NACK 0x4 == counter overflow EmSend4bit(CARD_NACK_NA); } else { counters[index] = val; // send ACK EmSend4bit(CARD_ACK); } } p_response = NULL; } else if (receivedCmd[0] == MIFARE_ULEV1_CHECKTEAR && len == 4 && tagType == 7) { // Received a CHECK_TEARING_EVENT -- // first 12 blocks of emu are [getversion answer - check tearing - pack - 0x00 - signature] uint8_t index = receivedCmd[1]; if (index > 2) { // send NACK 0x0 == invalid argument EmSend4bit(CARD_NACK_IV); } else { uint8_t cmd[3]; cmd[0] = tearings[index]; AddCrc14A(cmd, sizeof(cmd) - 2); EmSendCmd(cmd, sizeof(cmd)); } p_response = NULL; } else if (receivedCmd[0] == ISO14443A_CMD_HALT && len == 4) { // Received a HALT LogTrace(receivedCmd, Uart.len, Uart.startTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, true); p_response = NULL; order = ORDER_HALTED; } else if (receivedCmd[0] == MIFARE_ULEV1_VERSION && len == 3 && (tagType == 2 || tagType == 7)) { p_response = &responses[VERSION]; } else if ((receivedCmd[0] == MIFARE_AUTH_KEYA || receivedCmd[0] == MIFARE_AUTH_KEYB) && len == 4 && tagType != 2 && tagType != 7) { // Received an authentication request cardAUTHKEY = receivedCmd[0] - 0x60; cardAUTHSC = receivedCmd[1] / 4; // received block num // incease nonce at AUTH requests. this is time consuming. nonce = prng_successor(GetTickCount(), 32); num_to_bytes(nonce, 4, dynamic_response_info.response); dynamic_response_info.response_n = 4; prepare_tag_modulation(&dynamic_response_info, DYNAMIC_MODULATION_BUFFER_SIZE); p_response = &dynamic_response_info; order = ORDER_AUTH; } else if (receivedCmd[0] == ISO14443A_CMD_RATS && len == 4) { // Received a RATS request if (tagType == 1 || tagType == 2) { // RATS not supported EmSend4bit(CARD_NACK_NA); p_response = NULL; } else { p_response = &responses[RATS]; order = ORDER_RATS; } } else if (receivedCmd[0] == MIFARE_ULC_AUTH_1) { // ULC authentication, or Desfire Authentication LogTrace(receivedCmd, Uart.len, Uart.startTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, true); p_response = NULL; } else if (receivedCmd[0] == MIFARE_ULEV1_AUTH && len == 7 && tagType == 7) { // NTAG / EV-1 authentication // PWD stored in dump now uint8_t pwd[4]; emlGetMemBt(pwd, (pages - 1) * 4 + MFU_DUMP_PREFIX_LENGTH, sizeof(pwd)); if (memcmp(receivedCmd + 1, pwd, 4) == 0) { uint8_t cmd[4]; emlGetMemBt(cmd, pages * 4 + MFU_DUMP_PREFIX_LENGTH, 2); AddCrc14A(cmd, sizeof(cmd) - 2); EmSendCmd(cmd, sizeof(cmd)); } else { EmSend4bit(CARD_NACK_NA); if (DBGLEVEL >= DBG_DEBUG) Dbprintf("Auth attempt: %08x", bytes_to_num(receivedCmd + 1, 4)); } p_response = NULL; } else if (receivedCmd[0] == MIFARE_ULEV1_VCSL && len == 23 && tagType == 7) { uint8_t cmd[3]; emlGetMemBt(cmd, (pages - 2) * 4 + 1 + MFU_DUMP_PREFIX_LENGTH, 1); AddCrc14A(cmd, sizeof(cmd) - 2); EmSendCmd(cmd, sizeof(cmd)); p_response = NULL; } else { // Check for ISO 14443A-4 compliant commands, look at left nibble switch (receivedCmd[0]) { case 0x02: case 0x03: { // IBlock (command no CID) dynamic_response_info.response[0] = receivedCmd[0]; dynamic_response_info.response[1] = 0x90; dynamic_response_info.response[2] = 0x00; dynamic_response_info.response_n = 3; } break; case 0x0B: case 0x0A: { // IBlock (command CID) dynamic_response_info.response[0] = receivedCmd[0]; dynamic_response_info.response[1] = 0x00; dynamic_response_info.response[2] = 0x90; dynamic_response_info.response[3] = 0x00; dynamic_response_info.response_n = 4; } break; case 0x1A: case 0x1B: { // Chaining command dynamic_response_info.response[0] = 0xaa | ((receivedCmd[0]) & 1); dynamic_response_info.response_n = 2; } break; case 0xAA: case 0xBB: { dynamic_response_info.response[0] = receivedCmd[0] ^ 0x11; dynamic_response_info.response_n = 2; } break; case 0xBA: { // ping / pong dynamic_response_info.response[0] = 0xAB; dynamic_response_info.response[1] = 0x00; dynamic_response_info.response_n = 2; } break; case 0xCA: case 0xC2: { // Readers sends deselect command dynamic_response_info.response[0] = 0xCA; dynamic_response_info.response[1] = 0x00; dynamic_response_info.response_n = 2; } break; default: { // Never seen this command before LogTrace(receivedCmd, Uart.len, Uart.startTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, true); if (DBGLEVEL >= DBG_DEBUG) { Dbprintf("Received unknown command (len=%d):", len); Dbhexdump(len, receivedCmd, false); } // Do not respond dynamic_response_info.response_n = 0; order = ORDER_NONE; // back to work state } break; } if (dynamic_response_info.response_n > 0) { // Copy the CID from the reader query dynamic_response_info.response[1] = receivedCmd[1]; // Add CRC bytes, always used in ISO 14443A-4 compliant cards AddCrc14A(dynamic_response_info.response, dynamic_response_info.response_n); dynamic_response_info.response_n += 2; if (prepare_tag_modulation(&dynamic_response_info, DYNAMIC_MODULATION_BUFFER_SIZE) == false) { if (DBGLEVEL >= DBG_DEBUG) DbpString("Error preparing tag response"); LogTrace(receivedCmd, Uart.len, Uart.startTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, true); break; } p_response = &dynamic_response_info; } } // Count number of wakeups received after a halt if (order == ORDER_WUPA && lastorder == ORDER_HALTED) { happened++; } // Count number of other messages after a halt if (order != ORDER_WUPA && lastorder == ORDER_HALTED) { happened2++; } cmdsRecvd++; if (p_response != NULL) { EmSendPrecompiledCmd(p_response); } } switch_off(); set_tracing(false); BigBuf_free_keep_EM(); if (DBGLEVEL >= DBG_EXTENDED) { Dbprintf("-[ Wake ups after halt [%d]", happened); Dbprintf("-[ Messages after halt [%d]", happened2); Dbprintf("-[ Num of received cmd [%d]", cmdsRecvd); Dbprintf("-[ Num of moebius tries [%d]", moebius_count); } reply_ng(CMD_HF_MIFARE_SIMULATE, retval, NULL, 0); } // prepare a delayed transfer. This simply shifts ToSend[] by a number // of bits specified in the delay parameter. void PrepareDelayedTransfer(uint16_t delay) { delay &= 0x07; if (!delay) return; uint8_t bitmask = 0; uint8_t bits_shifted = 0; for (uint16_t i = 0; i < delay; i++) bitmask |= (0x01 << i); ToSend[ToSendMax++] = 0x00; for (uint16_t i = 0; i < ToSendMax; i++) { uint8_t 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: transfer at next possible time, taking into account // request guard time and frame delay time // if == 0: transfer immediately and return time of transfer // if != 0: delay transfer until time specified //------------------------------------------------------------------------------------- static void TransmitFor14443a(const uint8_t *cmd, uint16_t len, uint32_t *timing) { if (!hf_field_active) return; FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD); if (timing) { if (*timing == 0) // Measure time *timing = (GetCountSspClk() + 8) & 0xfffffff8; else PrepareDelayedTransfer(*timing & 0x00000007); // Delay transfer (fine tuning - up to 7 MF clock ticks) if (DBGLEVEL >= DBG_EXTENDED && GetCountSspClk() >= (*timing & 0xfffffff8)) Dbprintf("TransmitFor14443a: Missed timing"); while (GetCountSspClk() < (*timing & 0xfffffff8)) {}; // Delay transfer (multiple of 8 MF clock ticks) LastTimeProxToAirStart = *timing; } else { uint32_t ThisTransferTime = 0; ThisTransferTime = ((MAX(NextTransferTime, GetCountSspClk()) & 0xfffffff8) + 8); while (GetCountSspClk() < ThisTransferTime) {}; LastTimeProxToAirStart = ThisTransferTime; } uint16_t c = 0; while (c < len) { if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { AT91C_BASE_SSC->SSC_THR = cmd[c]; c++; } } NextTransferTime = MAX(NextTransferTime, LastTimeProxToAirStart + REQUEST_GUARD_TIME); } //----------------------------------------------------------------------------- // Prepare reader command (in bits, support short frames) to send to FPGA //----------------------------------------------------------------------------- void CodeIso14443aBitsAsReaderPar(const uint8_t *cmd, uint16_t bits, const uint8_t *par) { int last = 0; ToSendReset(); // Start of Communication (Seq. Z) ToSend[++ToSendMax] = SEC_Z; LastProxToAirDuration = 8 * (ToSendMax + 1) - 6; size_t bytecount = nbytes(bits); // Generate send structure for the data bits for (int i = 0; i < bytecount; i++) { // Get the current byte to send uint8_t b = cmd[i]; size_t bitsleft = MIN((bits - (i * 8)), 8); int j; for (j = 0; j < bitsleft; j++) { if (b & 1) { // Sequence X ToSend[++ToSendMax] = SEC_X; LastProxToAirDuration = 8 * (ToSendMax + 1) - 2; last = 1; } else { if (last == 0) { // Sequence Z ToSend[++ToSendMax] = SEC_Z; LastProxToAirDuration = 8 * (ToSendMax + 1) - 6; } else { // Sequence Y ToSend[++ToSendMax] = SEC_Y; last = 0; } } b >>= 1; } // Only transmit parity bit if we transmitted a complete byte if (j == 8 && par != NULL) { // Get the parity bit if (par[i >> 3] & (0x80 >> (i & 0x0007))) { // Sequence X ToSend[++ToSendMax] = SEC_X; LastProxToAirDuration = 8 * (ToSendMax + 1) - 2; last = 1; } else { if (last == 0) { // Sequence Z ToSend[++ToSendMax] = SEC_Z; LastProxToAirDuration = 8 * (ToSendMax + 1) - 6; } else { // Sequence Y ToSend[++ToSendMax] = SEC_Y; last = 0; } } } } // End of Communication: Logic 0 followed by Sequence Y if (last == 0) { // Sequence Z ToSend[++ToSendMax] = SEC_Z; LastProxToAirDuration = 8 * (ToSendMax + 1) - 6; } else { // Sequence Y ToSend[++ToSendMax] = SEC_Y; } ToSend[++ToSendMax] = SEC_Y; // Convert to length of command: ToSendMax++; } //----------------------------------------------------------------------------- // Prepare reader command to send to FPGA //----------------------------------------------------------------------------- void CodeIso14443aAsReaderPar(const uint8_t *cmd, uint16_t len, const uint8_t *par) { CodeIso14443aBitsAsReaderPar(cmd, len * 8, par); } //----------------------------------------------------------------------------- // Wait for commands from reader // Stop when button is pressed (return 1) or field was gone (return 2) // Or return 0 when command is captured //----------------------------------------------------------------------------- int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *par) { *len = 0; uint32_t timer = 0; int analogCnt = 0; int analogAVG = 0; // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen // only, since we are receiving, not transmitting). // Signal field is off with the appropriate LED LED_D_OFF(); FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN); // Set ADC to read field strength AT91C_BASE_ADC->ADC_CR = AT91C_ADC_SWRST; AT91C_BASE_ADC->ADC_MR = ADC_MODE_PRESCALE(63) | ADC_MODE_STARTUP_TIME(1) | ADC_MODE_SAMPLE_HOLD_TIME(15); AT91C_BASE_ADC->ADC_CHER = ADC_CHANNEL(ADC_CHAN_HF); // start ADC AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START; // Now run a 'software UART' on the stream of incoming samples. Uart14aInit(received, par); // Clear RXRDY: uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR; (void)b; uint16_t check = 0; for (;;) { WDT_HIT(); if (check == 1000) { if (BUTTON_PRESS() || data_available()) return 1; check = 0; } ++check; // test if the field exists if (AT91C_BASE_ADC->ADC_SR & ADC_END_OF_CONVERSION(ADC_CHAN_HF)) { analogCnt++; analogAVG += AT91C_BASE_ADC->ADC_CDR[ADC_CHAN_HF]; AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START; if (analogCnt >= 32) { if ((MAX_ADC_HF_VOLTAGE_RDV40 * (analogAVG / analogCnt) >> 10) < MF_MINFIELDV) { if (timer == 0) { timer = GetTickCount(); } else { // 50ms no field --> card to idle state if (GetTickCountDelta(timer) > 50) { return 2; } } } else { timer = 0; } analogCnt = 0; analogAVG = 0; } } // receive and test the miller decoding if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { b = (uint8_t)AT91C_BASE_SSC->SSC_RHR; if (MillerDecoding(b, 0)) { *len = Uart.len; return 0; } } } } int EmSendCmd14443aRaw(uint8_t *resp, uint16_t respLen) { volatile uint8_t b; uint16_t i = 0; uint32_t ThisTransferTime; bool correctionNeeded; // Modulate Manchester FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_MOD); // Include correction bit if necessary if (Uart.bitCount == 7) { // Short tags (7 bits) don't have parity, determine the correct value from MSB correctionNeeded = Uart.output[0] & 0x40; } else { // The parity bits are left-aligned correctionNeeded = Uart.parity[(Uart.len - 1) / 8] & (0x80 >> ((Uart.len - 1) & 7)); } // 1236, so correction bit needed i = (correctionNeeded) ? 0 : 1; // clear receiving shift register and holding register while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY)); b = AT91C_BASE_SSC->SSC_RHR; (void) b; while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY)); b = AT91C_BASE_SSC->SSC_RHR; (void) b; // wait for the FPGA to signal fdt_indicator == 1 (the FPGA is ready to queue new data in its delay line) for (uint8_t j = 0; j < 5; j++) { // allow timeout - better late than never while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY)); if (AT91C_BASE_SSC->SSC_RHR) break; } while ((ThisTransferTime = GetCountSspClk()) & 0x00000007); // Clear TXRDY: AT91C_BASE_SSC->SSC_THR = SEC_F; // send cycle for (; i < respLen;) { if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { AT91C_BASE_SSC->SSC_THR = resp[i++]; FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR; } if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { b = (uint16_t)(AT91C_BASE_SSC->SSC_RHR); (void)b; } if (BUTTON_PRESS()) break; } // Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again: uint8_t fpga_queued_bits = FpgaSendQueueDelay >> 3; for (i = 0; i <= fpga_queued_bits / 8 + 1;) { if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { AT91C_BASE_SSC->SSC_THR = SEC_F; FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR; i++; } } LastTimeProxToAirStart = ThisTransferTime + (correctionNeeded ? 8 : 0); return 0; } int EmSend4bit(uint8_t resp) { Code4bitAnswerAsTag(resp); int res = EmSendCmd14443aRaw(ToSend, ToSendMax); // do the tracing for the previous reader request and this tag answer: uint8_t par[1] = {0x00}; GetParity(&resp, 1, par); EmLogTrace(Uart.output, Uart.len, Uart.startTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, &resp, 1, LastTimeProxToAirStart * 16 + DELAY_ARM2AIR_AS_TAG, (LastTimeProxToAirStart + LastProxToAirDuration) * 16 + DELAY_ARM2AIR_AS_TAG, par); return res; } int EmSendCmdPar(uint8_t *resp, uint16_t respLen, uint8_t *par) { return EmSendCmdParEx(resp, respLen, par, false); } int EmSendCmdParEx(uint8_t *resp, uint16_t respLen, uint8_t *par, bool collision) { CodeIso14443aAsTagPar(resp, respLen, par, collision); int res = EmSendCmd14443aRaw(ToSend, ToSendMax); // do the tracing for the previous reader request and this tag answer: EmLogTrace(Uart.output, Uart.len, Uart.startTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, resp, respLen, LastTimeProxToAirStart * 16 + DELAY_ARM2AIR_AS_TAG, (LastTimeProxToAirStart + LastProxToAirDuration) * 16 + DELAY_ARM2AIR_AS_TAG, par); return res; } int EmSendCmd(uint8_t *resp, uint16_t respLen) { return EmSendCmdEx(resp, respLen, false); } int EmSendCmdEx(uint8_t *resp, uint16_t respLen, bool collision) { uint8_t par[MAX_PARITY_SIZE] = {0x00}; GetParity(resp, respLen, par); return EmSendCmdParEx(resp, respLen, par, collision); } int EmSendPrecompiledCmd(tag_response_info_t *p_response) { int ret = EmSendCmd14443aRaw(p_response->modulation, p_response->modulation_n); // do the tracing for the previous reader request and this tag answer: uint8_t par[MAX_PARITY_SIZE] = {0x00}; GetParity(p_response->response, p_response->response_n, par); EmLogTrace(Uart.output, Uart.len, Uart.startTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime * 16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, p_response->response, p_response->response_n, LastTimeProxToAirStart * 16 + DELAY_ARM2AIR_AS_TAG, (LastTimeProxToAirStart + p_response->ProxToAirDuration) * 16 + DELAY_ARM2AIR_AS_TAG, par); if (DBGLEVEL >= DBG_EXTENDED) { Dbprintf("response_info->response %02X", p_response->response); Dbprintf("response_info->response_n %02X", p_response->response_n); Dbprintf("response_info->par %02X", &(p_response->par)); } return ret; } bool EmLogTrace(uint8_t *reader_data, uint16_t reader_len, uint32_t reader_StartTime, uint32_t reader_EndTime, uint8_t *reader_Parity, uint8_t *tag_data, uint16_t tag_len, uint32_t tag_StartTime, uint32_t tag_EndTime, uint8_t *tag_Parity) { // we cannot exactly measure the end and start of a received command from reader. However we know that the delay from // end of the received command to start of the tag's (simulated by us) answer is n*128+20 or n*128+84 resp. // with n >= 9. The start of the tags answer can be measured and therefore the end of the received command be calculated: uint16_t reader_modlen = reader_EndTime - reader_StartTime; uint16_t approx_fdt = tag_StartTime - reader_EndTime; uint16_t exact_fdt = (approx_fdt - 20 + 32) / 64 * 64 + 20; reader_EndTime = tag_StartTime - exact_fdt; reader_StartTime = reader_EndTime - reader_modlen; if (!LogTrace(reader_data, reader_len, reader_StartTime, reader_EndTime, reader_Parity, true)) return false; else return (!LogTrace(tag_data, tag_len, tag_StartTime, tag_EndTime, tag_Parity, false)); } //----------------------------------------------------------------------------- // Kovio - Thinfilm barcode. TAG-TALK-FIRST - // Wait a certain time for tag response // If a response is captured return TRUE // If it takes too long return FALSE //----------------------------------------------------------------------------- bool GetIso14443aAnswerFromTag_Thinfilm(uint8_t *receivedResponse, uint8_t *received_len) { if (!hf_field_active) return false; // Set FPGA mode to "reader listen mode", no modulation (listen // only, since we are receiving, not transmitting). // 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 Demod14aInit(receivedResponse, NULL); // clear RXRDY: uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR; (void)b; uint32_t receive_timer = GetTickCount(); for (;;) { WDT_HIT(); if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { b = (uint8_t)AT91C_BASE_SSC->SSC_RHR; if (ManchesterDecoding_Thinfilm(b)) { *received_len = Demod.len; // log LogTrace(receivedResponse, Demod.len, Demod.startTime * 16 - DELAY_AIR2ARM_AS_READER, Demod.endTime * 16 - DELAY_AIR2ARM_AS_READER, NULL, false); return true; } } if (GetTickCountDelta(receive_timer) > 100) break; } *received_len = Demod.len; // log LogTrace(receivedResponse, Demod.len, Demod.startTime * 16 - DELAY_AIR2ARM_AS_READER, Demod.endTime * 16 - DELAY_AIR2ARM_AS_READER, NULL, false); return false; } //----------------------------------------------------------------------------- // Wait a certain time for tag response // If a response is captured return TRUE // If it takes too long return FALSE //----------------------------------------------------------------------------- static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint8_t *receivedResponsePar, uint16_t offset) { uint32_t c = 0; if (!hf_field_active) return false; // Set FPGA mode to "reader listen mode", no modulation (listen // only, since we are receiving, not transmitting). // 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 Demod14aInit(receivedResponse, receivedResponsePar); // clear RXRDY: uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR; (void)b; uint32_t timeout = iso14a_get_timeout(); uint32_t receive_timer = GetTickCount(); for (;;) { WDT_HIT(); if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { b = (uint8_t)AT91C_BASE_SSC->SSC_RHR; if (ManchesterDecoding(b, offset, 0)) { NextTransferTime = MAX(NextTransferTime, Demod.endTime - (DELAY_AIR2ARM_AS_READER + DELAY_ARM2AIR_AS_READER) / 16 + FRAME_DELAY_TIME_PICC_TO_PCD); return true; } else if (c++ > timeout && Demod.state == DEMOD_14A_UNSYNCD) { return false; } } // timeout already in ms + 100ms guard time if (GetTickCountDelta(receive_timer) > timeout + 100) break; } return false; } void ReaderTransmitBitsPar(uint8_t *frame, uint16_t bits, uint8_t *par, uint32_t *timing) { CodeIso14443aBitsAsReaderPar(frame, bits, par); // Send command to tag TransmitFor14443a(ToSend, ToSendMax, timing); if (trigger) LED_A_ON(); LogTrace(frame, nbytes(bits), (LastTimeProxToAirStart << 4) + DELAY_ARM2AIR_AS_READER, ((LastTimeProxToAirStart + LastProxToAirDuration) << 4) + DELAY_ARM2AIR_AS_READER, par, true); } void ReaderTransmitPar(uint8_t *frame, uint16_t len, uint8_t *par, uint32_t *timing) { ReaderTransmitBitsPar(frame, len * 8, par, timing); } void ReaderTransmitBits(uint8_t *frame, uint16_t len, uint32_t *timing) { // Generate parity and redirect uint8_t par[MAX_PARITY_SIZE] = {0x00}; GetParity(frame, len / 8, par); ReaderTransmitBitsPar(frame, len, par, timing); } void ReaderTransmit(uint8_t *frame, uint16_t len, uint32_t *timing) { // Generate parity and redirect uint8_t par[MAX_PARITY_SIZE] = {0x00}; GetParity(frame, len, par); ReaderTransmitBitsPar(frame, len * 8, par, timing); } int ReaderReceiveOffset(uint8_t *receivedAnswer, uint16_t offset, uint8_t *par) { if (!GetIso14443aAnswerFromTag(receivedAnswer, par, offset)) return false; LogTrace(receivedAnswer, Demod.len, Demod.startTime * 16 - DELAY_AIR2ARM_AS_READER, Demod.endTime * 16 - DELAY_AIR2ARM_AS_READER, par, false); return Demod.len; } int ReaderReceive(uint8_t *receivedAnswer, uint8_t *par) { if (!GetIso14443aAnswerFromTag(receivedAnswer, par, 0)) return false; LogTrace(receivedAnswer, Demod.len, Demod.startTime * 16 - DELAY_AIR2ARM_AS_READER, Demod.endTime * 16 - DELAY_AIR2ARM_AS_READER, par, false); return Demod.len; } // This function misstreats the ISO 14443a anticollision procedure. // by fooling the reader there is a collision and forceing the reader to // increase the uid bytes. The might be an overflow, DoS will occure. void iso14443a_antifuzz(uint32_t flags) { // We need to listen to the high-frequency, peak-detected path. iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN); BigBuf_free_keep_EM(); clear_trace(); set_tracing(true); int len = 0; // allocate buffers: uint8_t *received = BigBuf_malloc(MAX_FRAME_SIZE); uint8_t *receivedPar = BigBuf_malloc(MAX_PARITY_SIZE); uint8_t *resp = BigBuf_malloc(20); memset(resp, 0xFF, 20); LED_A_ON(); for (;;) { WDT_HIT(); // Clean receive command buffer if (!GetIso14443aCommandFromReader(received, receivedPar, &len)) { Dbprintf("Anti-fuzz stopped. Trace length: %d ", BigBuf_get_traceLen()); break; } if (received[0] == ISO14443A_CMD_WUPA || received[0] == ISO14443A_CMD_REQA) { resp[0] = 0x04; resp[1] = 0x00; if ((flags & FLAG_7B_UID_IN_DATA) == FLAG_7B_UID_IN_DATA) { resp[0] = 0x44; } EmSendCmd(resp, 2); continue; } // Received request for UID (cascade 1) //if (received[1] >= 0x20 && received[1] <= 0x57 && received[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT) { if (received[1] >= 0x20 && received[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT) { resp[0] = 0xFF; resp[1] = 0xFF; resp[2] = 0xFF; resp[3] = 0xFF; resp[4] = resp[0] ^ resp[1] ^ resp[2] ^ resp[3]; colpos = 0; if ((flags & FLAG_7B_UID_IN_DATA) == FLAG_7B_UID_IN_DATA) { resp[0] = 0x88; colpos = 8; } EmSendCmdEx(resp, 5, true); if (DBGLEVEL >= DBG_EXTENDED) Dbprintf("ANTICOLL or SELECT %x", received[1]); LED_D_INV(); continue; } else if (received[1] == 0x20 && received[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT_2) { // Received request for UID (cascade 2) if (DBGLEVEL >= DBG_EXTENDED) Dbprintf("ANTICOLL or SELECT_2"); } else if (received[1] == 0x70 && received[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT) { // Received a SELECT (cascade 1) } else if (received[1] == 0x70 && received[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT_2) { // Received a SELECT (cascade 2) } else { Dbprintf("unknown command %x", received[0]); } } reply_old(CMD_ACK, 1, 0, 0, 0, 0); switch_off(); BigBuf_free_keep_EM(); } static void iso14a_set_ATS_times(uint8_t *ats) { if (ats[0] > 1) { // there is a format byte T0 if ((ats[1] & 0x20) == 0x20) { // there is an interface byte TB(1) uint8_t tb1; if ((ats[1] & 0x10) == 0x10) { // there is an interface byte TA(1) preceding TB(1) tb1 = ats[3]; } else { tb1 = ats[2]; } uint8_t fwi = (tb1 & 0xf0) >> 4; // frame waiting time integer (FWI) if (fwi != 15) { uint32_t fwt = 256 * 16 * (1 << fwi); // frame waiting time (FWT) in 1/fc iso14a_set_timeout(fwt / (8 * 16)); } uint8_t sfgi = tb1 & 0x0f; // startup frame guard time integer (SFGI) if (sfgi != 0 && sfgi != 15) { uint32_t sfgt = 256 * 16 * (1 << sfgi); // startup frame guard time (SFGT) in 1/fc NextTransferTime = MAX(NextTransferTime, Demod.endTime + (sfgt - DELAY_AIR2ARM_AS_READER - DELAY_ARM2AIR_AS_READER) / 16); } } } } static int GetATQA(uint8_t *resp, uint8_t *resp_par) { #define WUPA_RETRY_TIMEOUT 10 // 10ms uint8_t wupa[] = { ISO14443A_CMD_WUPA }; // 0x26 - REQA 0x52 - WAKE-UP uint32_t save_iso14a_timeout = iso14a_get_timeout(); iso14a_set_timeout(1236 / (16 * 8) + 1); // response to WUPA is expected at exactly 1236/fc. No need to wait longer. uint32_t start_time = GetTickCount(); int len; // we may need several tries if we did send an unknown command or a wrong authentication before... do { // Broadcast for a card, WUPA (0x52) will force response from all cards in the field ReaderTransmitBitsPar(wupa, 7, NULL, NULL); // Receive the ATQA len = ReaderReceive(resp, resp_par); } while (len == 0 && GetTickCountDelta(start_time) <= WUPA_RETRY_TIMEOUT); iso14a_set_timeout(save_iso14a_timeout); return len; } // performs iso14443a anticollision (optional) and card select procedure // fills the uid and cuid pointer unless NULL // fills the card info record unless NULL // if anticollision is false, then the UID must be provided in uid_ptr[] // and num_cascades must be set (1: 4 Byte UID, 2: 7 Byte UID, 3: 10 Byte UID) // requests ATS unless no_rats is true int iso14443a_select_card(uint8_t *uid_ptr, iso14a_card_select_t *p_card, uint32_t *cuid_ptr, bool anticollision, uint8_t num_cascades, bool no_rats) { uint8_t resp[MAX_FRAME_SIZE] = {0}; // theoretically. A usual RATS will be much smaller uint8_t resp_par[MAX_PARITY_SIZE] = {0}; uint8_t sak = 0x04; // cascade uid int cascade_level = 0; if (p_card) { p_card->uidlen = 0; memset(p_card->uid, 0, 10); p_card->ats_len = 0; } if (!GetATQA(resp, resp_par)) { return 0; } if (p_card) { p_card->atqa[0] = resp[0]; p_card->atqa[1] = resp[1]; } if (anticollision) { // clear uid if (uid_ptr) memset(uid_ptr, 0, 10); } // check for proprietary anticollision: if ((resp[0] & 0x1F) == 0) return 3; // OK we will select at least at cascade 1, lets see if first byte of UID was 0x88 in // which case we need to make a cascade 2 request and select - this is a long UID // While the UID is not complete, the 3nd bit (from the right) is set in the SAK. for (; sak & 0x04; cascade_level++) { // SELECT_* (L1: 0x93, L2: 0x95, L3: 0x97) uint8_t sel_all[] = { ISO14443A_CMD_ANTICOLL_OR_SELECT, 0x20 }; uint8_t sel_uid[] = { ISO14443A_CMD_ANTICOLL_OR_SELECT, 0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; uint8_t uid_resp[4] = {0}; sel_uid[0] = sel_all[0] = 0x93 + cascade_level * 2; if (anticollision) { // SELECT_ALL ReaderTransmit(sel_all, sizeof(sel_all), NULL); if (!ReaderReceive(resp, resp_par)) return 0; if (Demod.collisionPos) { // we had a collision and need to construct the UID bit by bit memset(uid_resp, 0, 4); uint16_t uid_resp_bits = 0; uint16_t collision_answer_offset = 0; // anti-collision-loop: while (Demod.collisionPos) { Dbprintf("Multiple tags detected. Collision after Bit %d", Demod.collisionPos); for (uint16_t i = collision_answer_offset; i < Demod.collisionPos; i++, uid_resp_bits++) { // add valid UID bits before collision point uint16_t UIDbit = (resp[i / 8] >> (i % 8)) & 0x01; uid_resp[uid_resp_bits / 8] |= UIDbit << (uid_resp_bits % 8); } uid_resp[uid_resp_bits / 8] |= 1 << (uid_resp_bits % 8); // next time select the card(s) with a 1 in the collision position uid_resp_bits++; // construct anticollosion command: sel_uid[1] = ((2 + uid_resp_bits / 8) << 4) | (uid_resp_bits & 0x07); // length of data in bytes and bits for (uint16_t i = 0; i <= uid_resp_bits / 8; i++) { sel_uid[2 + i] = uid_resp[i]; } collision_answer_offset = uid_resp_bits % 8; ReaderTransmitBits(sel_uid, 16 + uid_resp_bits, NULL); if (!ReaderReceiveOffset(resp, collision_answer_offset, resp_par)) return 0; } // finally, add the last bits and BCC of the UID for (uint16_t i = collision_answer_offset; i < (Demod.len - 1) * 8; i++, uid_resp_bits++) { uint16_t UIDbit = (resp[i / 8] >> (i % 8)) & 0x01; uid_resp[uid_resp_bits / 8] |= UIDbit << (uid_resp_bits % 8); } } else { // no collision, use the response to SELECT_ALL as current uid memcpy(uid_resp, resp, 4); } } else { if (cascade_level < num_cascades - 1) { uid_resp[0] = 0x88; memcpy(uid_resp + 1, uid_ptr + cascade_level * 3, 3); } else { memcpy(uid_resp, uid_ptr + cascade_level * 3, 4); } } size_t uid_resp_len = 4; // calculate crypto UID. Always use last 4 Bytes. if (cuid_ptr) *cuid_ptr = bytes_to_num(uid_resp, 4); // Construct SELECT UID command sel_uid[1] = 0x70; // transmitting a full UID (1 Byte cmd, 1 Byte NVB, 4 Byte UID, 1 Byte BCC, 2 Bytes CRC) memcpy(sel_uid + 2, uid_resp, 4); // the UID received during anticollision, or the provided UID sel_uid[6] = sel_uid[2] ^ sel_uid[3] ^ sel_uid[4] ^ sel_uid[5]; // calculate and add BCC AddCrc14A(sel_uid, 7); // calculate and add CRC ReaderTransmit(sel_uid, sizeof(sel_uid), NULL); // Receive the SAK if (!ReaderReceive(resp, resp_par)) return 0; sak = resp[0]; // Test if more parts of the uid are coming if ((sak & 0x04) /* && uid_resp[0] == 0x88 */) { // Remove first byte, 0x88 is not an UID byte, it CT, see page 3 of: // http://www.nxp.com/documents/application_note/AN10927.pdf uid_resp[0] = uid_resp[1]; uid_resp[1] = uid_resp[2]; uid_resp[2] = uid_resp[3]; uid_resp_len = 3; } if (uid_ptr && anticollision) memcpy(uid_ptr + (cascade_level * 3), uid_resp, uid_resp_len); if (p_card) { memcpy(p_card->uid + (cascade_level * 3), uid_resp, uid_resp_len); p_card->uidlen += uid_resp_len; } } if (p_card) { p_card->sak = sak; } // PICC compilant with iso14443a-4 ---> (SAK & 0x20 != 0) if ((sak & 0x20) == 0) return 2; // RATS, Request for answer to select if (!no_rats) { uint8_t rats[] = { ISO14443A_CMD_RATS, 0x80, 0x00, 0x00 }; // FSD=256, FSDI=8, CID=0 AddCrc14A(rats, 2); ReaderTransmit(rats, sizeof(rats), NULL); int len = ReaderReceive(resp, resp_par); if (!len) return 0; if (p_card) { memcpy(p_card->ats, resp, sizeof(p_card->ats)); p_card->ats_len = len; } // reset the PCB block number iso14_pcb_blocknum = 0; // set default timeout and delay next transfer based on ATS iso14a_set_ATS_times(resp); } return 1; } int iso14443a_fast_select_card(uint8_t *uid_ptr, uint8_t num_cascades) { uint8_t resp[5] = {0}; // theoretically. A usual RATS will be much smaller uint8_t resp_par[1] = {0}; uint8_t uid_resp[4] = {0}; uint8_t sak = 0x04; // cascade uid int cascade_level = 0; if (!GetATQA(resp, resp_par)) { return 0; } // OK we will select at least at cascade 1, lets see if first byte of UID was 0x88 in // which case we need to make a cascade 2 request and select - this is a long UID // While the UID is not complete, the 3nd bit (from the right) is set in the SAK. for (; sak & 0x04; cascade_level++) { uint8_t sel_all[] = { ISO14443A_CMD_ANTICOLL_OR_SELECT, 0x20 }; uint8_t sel_uid[] = { ISO14443A_CMD_ANTICOLL_OR_SELECT, 0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; // SELECT_* (L1: 0x93, L2: 0x95, L3: 0x97) sel_uid[0] = sel_all[0] = 0x93 + cascade_level * 2; if (cascade_level < num_cascades - 1) { uid_resp[0] = 0x88; memcpy(uid_resp + 1, uid_ptr + cascade_level * 3, 3); } else { memcpy(uid_resp, uid_ptr + cascade_level * 3, 4); } // Construct SELECT UID command //sel_uid[1] = 0x70; // transmitting a full UID (1 Byte cmd, 1 Byte NVB, 4 Byte UID, 1 Byte BCC, 2 Bytes CRC) memcpy(sel_uid + 2, uid_resp, 4); // the UID received during anticollision, or the provided UID sel_uid[6] = sel_uid[2] ^ sel_uid[3] ^ sel_uid[4] ^ sel_uid[5]; // calculate and add BCC AddCrc14A(sel_uid, 7); // calculate and add CRC ReaderTransmit(sel_uid, sizeof(sel_uid), NULL); // Receive the SAK if (!ReaderReceive(resp, resp_par)) return 0; sak = resp[0]; // Test if more parts of the uid are coming if ((sak & 0x04) /* && uid_resp[0] == 0x88 */) { // Remove first byte, 0x88 is not an UID byte, it CT, see page 3 of: // http://www.nxp.com/documents/application_note/AN10927.pdf uid_resp[0] = uid_resp[1]; uid_resp[1] = uid_resp[2]; uid_resp[2] = uid_resp[3]; } } return 1; } void iso14443a_setup(uint8_t fpga_minor_mode) { FpgaDownloadAndGo(FPGA_BITSTREAM_HF); // Set up the synchronous serial port FpgaSetupSsc(); // connect Demodulated Signal to ADC: SetAdcMuxFor(GPIO_MUXSEL_HIPKD); LED_D_OFF(); // Signal field is on with the appropriate LED if (fpga_minor_mode == FPGA_HF_ISO14443A_READER_MOD || fpga_minor_mode == FPGA_HF_ISO14443A_READER_LISTEN) LED_D_ON(); FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | fpga_minor_mode); SpinDelay(100); // Start the timer StartCountSspClk(); // Prepare the demodulation functions Demod14aReset(); Uart14aReset(); NextTransferTime = 2 * DELAY_ARM2AIR_AS_READER; iso14a_set_timeout(1060); // 106 * 10ms default hf_field_active = true; } void hf_field_off(void) { FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); LEDsoff(); hf_field_active = false; } /* Peter Fillmore 2015 Added card id field to the function info from ISO14443A standard b1 = Block Number b2 = RFU (always 1) b3 = depends on block b4 = Card ID following if set to 1 b5 = depends on block type b6 = depends on block type b7,b8 = block type. Coding of I-BLOCK: b8 b7 b6 b5 b4 b3 b2 b1 0 0 0 x x x 1 x b5 = chaining bit Coding of R-block: b8 b7 b6 b5 b4 b3 b2 b1 1 0 1 x x 0 1 x b5 = ACK/NACK Coding of S-block: b8 b7 b6 b5 b4 b3 b2 b1 1 1 x x x 0 1 0 b5,b6 = 00 - DESELECT 11 - WTX */ int iso14_apdu(uint8_t *cmd, uint16_t cmd_len, bool send_chaining, void *data, uint8_t *res) { uint8_t parity[MAX_PARITY_SIZE] = {0x00}; uint8_t real_cmd[cmd_len + 4]; if (cmd_len) { // ISO 14443 APDU frame: PCB [CID] [NAD] APDU CRC PCB=0x02 real_cmd[0] = 0x02; // bnr,nad,cid,chn=0; i-block(0x00) if (send_chaining) { real_cmd[0] |= 0x10; } // put block number into the PCB real_cmd[0] |= iso14_pcb_blocknum; memcpy(real_cmd + 1, cmd, cmd_len); } else { // R-block. ACK real_cmd[0] = 0xA2; // r-block + ACK real_cmd[0] |= iso14_pcb_blocknum; } AddCrc14A(real_cmd, cmd_len + 1); ReaderTransmit(real_cmd, cmd_len + 3, NULL); size_t len = ReaderReceive(data, parity); uint8_t *data_bytes = (uint8_t *) data; if (!len) { return 0; //DATA LINK ERROR } else { // S-Block WTX while (len && ((data_bytes[0] & 0xF2) == 0xF2)) { uint32_t save_iso14a_timeout = iso14a_get_timeout(); // temporarily increase timeout iso14a_set_timeout(MAX((data_bytes[1] & 0x3f) * save_iso14a_timeout, MAX_ISO14A_TIMEOUT)); // Transmit WTX back // byte1 - WTXM [1..59]. command FWT=FWT*WTXM data_bytes[1] = data_bytes[1] & 0x3f; // 2 high bits mandatory set to 0b // now need to fix CRC. AddCrc14A(data_bytes, len - 2); // transmit S-Block ReaderTransmit(data_bytes, len, NULL); // retrieve the result again (with increased timeout) len = ReaderReceive(data, parity); data_bytes = data; // restore timeout iso14a_set_timeout(save_iso14a_timeout); } // if we received an I- or R(ACK)-Block with a block number equal to the // current block number, toggle the current block number if (len >= 3 // PCB+CRC = 3 bytes && ((data_bytes[0] & 0xC0) == 0 // I-Block || (data_bytes[0] & 0xD0) == 0x80) // R-Block with ACK bit set to 0 && (data_bytes[0] & 0x01) == iso14_pcb_blocknum) { // equal block numbers iso14_pcb_blocknum ^= 1; } // if we received I-block with chaining we need to send ACK and receive another block of data if (res) *res = data_bytes[0]; // crc check if (len >= 3 && !CheckCrc14A(data_bytes, len)) { return -1; } } if (len) { // cut frame byte len -= 1; // memmove(data_bytes, data_bytes + 1, len); for (int i = 0; i < len; i++) data_bytes[i] = data_bytes[i + 1]; } return len; } //----------------------------------------------------------------------------- // Read an ISO 14443a tag. Send out commands and store answers. //----------------------------------------------------------------------------- // arg0 iso_14a flags // arg1 high :: number of bits, if you want to send 7bits etc // low :: len of commandbytes // arg2 timeout // d.asBytes command bytes to send void ReaderIso14443a(PacketCommandNG *c) { iso14a_command_t param = c->oldarg[0]; size_t len = c->oldarg[1] & 0xffff; size_t lenbits = c->oldarg[1] >> 16; uint32_t timeout = c->oldarg[2]; uint8_t *cmd = c->data.asBytes; uint32_t arg0; uint8_t buf[PM3_CMD_DATA_SIZE] = {0x00}; uint8_t par[MAX_PARITY_SIZE] = {0x00}; if ((param & ISO14A_CONNECT)) clear_trace(); set_tracing(true); if ((param & ISO14A_REQUEST_TRIGGER)) iso14a_set_trigger(true); if ((param & ISO14A_CONNECT)) { iso14443a_setup(FPGA_HF_ISO14443A_READER_LISTEN); // notify client selecting status. // if failed selecting, turn off antenna and quite. if (!(param & ISO14A_NO_SELECT)) { iso14a_card_select_t *card = (iso14a_card_select_t *)buf; arg0 = iso14443a_select_card(NULL, card, NULL, true, 0, param & ISO14A_NO_RATS); reply_mix(CMD_ACK, arg0, card->uidlen, 0, buf, sizeof(iso14a_card_select_t)); if (arg0 == 0) goto OUT; } } if ((param & ISO14A_SET_TIMEOUT)) iso14a_set_timeout(timeout); if ((param & ISO14A_APDU)) { uint8_t res; arg0 = iso14_apdu(cmd, len, (param & ISO14A_SEND_CHAINING), buf, &res); reply_old(CMD_ACK, arg0, res, 0, buf, sizeof(buf)); } if ((param & ISO14A_RAW)) { if ((param & ISO14A_APPEND_CRC)) { // Don't append crc on empty bytearray... if (len > 0) { if ((param & ISO14A_TOPAZMODE)) AddCrc14B(cmd, len); else AddCrc14A(cmd, len); len += 2; if (lenbits) lenbits += 16; } } if (lenbits > 0) { // want to send a specific number of bits (e.g. short commands) if ((param & ISO14A_TOPAZMODE)) { int bits_to_send = lenbits; uint16_t i = 0; ReaderTransmitBitsPar(&cmd[i++], MIN(bits_to_send, 7), NULL, NULL); // first byte is always short (7bits) and no parity bits_to_send -= 7; while (bits_to_send > 0) { ReaderTransmitBitsPar(&cmd[i++], MIN(bits_to_send, 8), NULL, NULL); // following bytes are 8 bit and no parity bits_to_send -= 8; } } else { GetParity(cmd, lenbits / 8, par); ReaderTransmitBitsPar(cmd, lenbits, par, NULL); // bytes are 8 bit with odd parity } } else { // want to send complete bytes only if ((param & ISO14A_TOPAZMODE)) { uint16_t i = 0; ReaderTransmitBitsPar(&cmd[i++], 7, NULL, NULL); // first byte: 7 bits, no paritiy while (i < len) { ReaderTransmitBitsPar(&cmd[i++], 8, NULL, NULL); // following bytes: 8 bits, no paritiy } } else { ReaderTransmit(cmd, len, NULL); // 8 bits, odd parity } } arg0 = ReaderReceive(buf, par); reply_old(CMD_ACK, arg0, 0, 0, buf, sizeof(buf)); } if ((param & ISO14A_REQUEST_TRIGGER)) iso14a_set_trigger(false); if ((param & ISO14A_NO_DISCONNECT)) return; OUT: hf_field_off(); set_tracing(false); } // 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) { if (nt1 == nt2) return 0; uint32_t nttmp1 = nt1; uint32_t nttmp2 = nt2; for (uint16_t 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 } #define PRNG_SEQUENCE_LENGTH (1 << 16) #define MAX_UNEXPECTED_RANDOM 4 // maximum number of unexpected (i.e. real) random numbers when trying to sync. Then give up. #define MAX_SYNC_TRIES 32 //----------------------------------------------------------------------------- // 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, uint8_t block, uint8_t keytype) { iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD); BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); set_tracing(true); uint8_t mf_auth[] = { keytype, block, 0x00, 0x00 }; uint8_t mf_nr_ar[] = {0, 0, 0, 0, 0, 0, 0, 0}; uint8_t uid[10] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}; uint8_t par_list[8] = {0, 0, 0, 0, 0, 0, 0, 0}; uint8_t ks_list[8] = {0, 0, 0, 0, 0, 0, 0, 0}; uint8_t receivedAnswer[MAX_MIFARE_FRAME_SIZE] = {0x00}; uint8_t receivedAnswerPar[MAX_MIFARE_PARITY_SIZE] = {0x00}; uint8_t par[1] = {0}; // maximum 8 Bytes to be sent here, 1 byte parity is therefore enough uint8_t nt_diff = 0; uint32_t nt = 0, previous_nt = 0, cuid = 0; uint32_t sync_time = GetCountSspClk() & 0xfffffff8; int32_t catch_up_cycles = 0; int32_t last_catch_up = 0; int32_t isOK = 0; uint16_t elapsed_prng_sequences = 1; uint16_t consecutive_resyncs = 0; uint16_t unexpected_random = 0; uint16_t sync_tries = 0; bool have_uid = false; uint8_t cascade_levels = 0; // static variables here, is re-used in the next call static uint32_t nt_attacked = 0; static int32_t sync_cycles = 0; static uint8_t par_low = 0; static uint8_t mf_nr_ar3 = 0; int return_status = PM3_SUCCESS; AddCrc14A(mf_auth, 2); if (first_try) { sync_cycles = PRNG_SEQUENCE_LENGTH; // Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces). nt_attacked = 0; mf_nr_ar3 = 0; par_low = 0; } else { // we were unsuccessful on a previous call. // Try another READER nonce (first 3 parity bits remain the same) mf_nr_ar3++; mf_nr_ar[3] = mf_nr_ar3; par[0] = par_low; } LED_C_ON(); uint16_t checkbtn_cnt = 0; uint16_t i; for (i = 0; true; ++i) { bool received_nack = false; WDT_HIT(); // Test if the action was cancelled if (checkbtn_cnt == 1000) { if (BUTTON_PRESS() || data_available()) { isOK = -1; return_status = PM3_EOPABORTED; break; } checkbtn_cnt = 0; } ++checkbtn_cnt; // this part is from Piwi's faster nonce collecting part in Hardnested. if (!have_uid) { // need a full select cycle to get the uid first iso14a_card_select_t card_info; if (!iso14443a_select_card(uid, &card_info, &cuid, true, 0, true)) { if (DBGLEVEL >= DBG_INFO) Dbprintf("Mifare: Can't select card (ALL)"); continue; } switch (card_info.uidlen) { case 4 : cascade_levels = 1; break; case 7 : cascade_levels = 2; break; case 10: cascade_levels = 3; break; default: break; } have_uid = true; } else { // no need for anticollision. We can directly select the card if (!iso14443a_fast_select_card(uid, cascade_levels)) { if (DBGLEVEL >= DBG_INFO) Dbprintf("Mifare: Can't select card (UID)"); continue; } } elapsed_prng_sequences = 1; // Sending timeslot of ISO14443a frame sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles; catch_up_cycles = 0; #define SYNC_TIME_BUFFER 16 // if there is only SYNC_TIME_BUFFER left before next planned sync, wait for next PRNG cycle // if we missed the sync time already or are about to miss it, advance to the next nonce repeat while (sync_time < GetCountSspClk() + SYNC_TIME_BUFFER) { ++elapsed_prng_sequences; 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" TAG nonce if (!ReaderReceive(receivedAnswer, receivedAnswerPar)) 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); // Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding int resp_res = ReaderReceive(receivedAnswer, receivedAnswerPar); if (resp_res == 1) received_nack = true; else if (resp_res == 4) { // did we get lucky and got our dummykey to be valid? // however we dont feed key w uid it the prng.. isOK = -6; break; } // we didn't calibrate our clock yet, // iceman: has to be calibrated every time. if (previous_nt && !nt_attacked) { int nt_distance = dist_nt(previous_nt, nt); // if no distance between, then we are in sync. if (nt_distance == 0) { nt_attacked = nt; } else { if (nt_distance == -99999) { // invalid nonce received unexpected_random++; if (unexpected_random > MAX_UNEXPECTED_RANDOM) { isOK = -3; // Card has an unpredictable PRNG. Give up break; } else { continue; // continue trying... } } if (++sync_tries > MAX_SYNC_TRIES) { isOK = -4; // Card's PRNG runs at an unexpected frequency or resets unexpectedly break; } sync_cycles = (sync_cycles - nt_distance) / elapsed_prng_sequences; // no negative sync_cycles if (sync_cycles <= 0) sync_cycles += PRNG_SEQUENCE_LENGTH; // reset sync_cycles if (sync_cycles > PRNG_SEQUENCE_LENGTH * 2) { sync_cycles = PRNG_SEQUENCE_LENGTH; sync_time = GetCountSspClk() & 0xfffffff8; } if (DBGLEVEL >= DBG_EXTENDED) Dbprintf("calibrating in cycle %d. nt_distance=%d, elapsed_prng_sequences=%d, new sync_cycles: %d\n", i, nt_distance, elapsed_prng_sequences, sync_cycles); LED_B_OFF(); continue; } } LED_B_OFF(); 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; } // average? catch_up_cycles /= elapsed_prng_sequences; if (catch_up_cycles == last_catch_up) { consecutive_resyncs++; } else { last_catch_up = catch_up_cycles; consecutive_resyncs = 0; } if (consecutive_resyncs < 3) { if (DBGLEVEL >= DBG_EXTENDED) { 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 += catch_up_cycles; if (DBGLEVEL >= DBG_EXTENDED) 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); last_catch_up = 0; catch_up_cycles = 0; consecutive_resyncs = 0; } continue; } // Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding if (received_nack) { 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[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 par_list[nt_diff] = reflect8(par[0]); ks_list[nt_diff] = receivedAnswer[0] ^ 0x05; // xor with NACK value to get keystream // 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[0] = par_low; } else { // No NACK. if (nt_diff == 0 && first_try) { par[0]++; if (par[0] == 0) { // tried all 256 possible parities without success. Card doesn't send NACK. isOK = -2; break; } } else { // Why this? par[0] = ((par[0] & 0x1F) + 1) | par_low; } } // reset the resyncs since we got a complete transaction on right time. consecutive_resyncs = 0; } // end for loop mf_nr_ar[3] &= 0x1F; if (DBGLEVEL >= DBG_EXTENDED) Dbprintf("Number of sent auth requests: %u", i); struct { int32_t isOK; uint8_t cuid[4]; uint8_t nt[4]; uint8_t par_list[8]; uint8_t ks_list[8]; uint8_t nr[4]; uint8_t ar[4]; } PACKED payload; payload.isOK = isOK; num_to_bytes(cuid, 4, payload.cuid); num_to_bytes(nt, 4, payload.nt); memcpy(payload.par_list, par_list, sizeof(payload.par_list)); memcpy(payload.ks_list, ks_list, sizeof(payload.ks_list)); memcpy(payload.nr, mf_nr_ar, sizeof(payload.nr)); memcpy(payload.ar, mf_nr_ar + 4, sizeof(payload.ar)); reply_ng(CMD_HF_MIFARE_READER, return_status, (uint8_t *)&payload, sizeof(payload)); hf_field_off(); set_tracing(false); } /* * Mifare Classic NACK-bug detection * Thanks to @doegox for the feedback and new approaches. */ void DetectNACKbug(void) { uint8_t mf_auth[] = {0x60, 0x00, 0xF5, 0x7B}; uint8_t mf_nr_ar[] = {0, 0, 0, 0, 0, 0, 0, 0}; uint8_t uid[10] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}; uint8_t receivedAnswer[MAX_MIFARE_FRAME_SIZE] = {0x00}; uint8_t receivedAnswerPar[MAX_MIFARE_PARITY_SIZE] = {0x00}; uint8_t par[1] = {0}; // maximum 8 Bytes to be sent here, 1 byte parity is therefore enough uint32_t nt = 0, previous_nt = 0, nt_attacked = 0, cuid = 0; int32_t catch_up_cycles = 0, last_catch_up = 0; uint8_t cascade_levels = 0, num_nacks = 0, isOK = 0; uint16_t elapsed_prng_sequences = 1; uint16_t consecutive_resyncs = 0; uint16_t unexpected_random = 0; uint16_t sync_tries = 0; uint32_t sync_time = 0; bool have_uid = false; int32_t status = PM3_SUCCESS; // Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces). int32_t sync_cycles = PRNG_SEQUENCE_LENGTH; BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); set_tracing(true); iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD); sync_time = GetCountSspClk() & 0xfffffff8; LED_C_ON(); uint16_t checkbtn_cnt = 0; uint16_t i; for (i = 1; true; ++i) { bool received_nack = false; // Cards always leaks a NACK, no matter the parity if ((i == 10) && (num_nacks == i - 1)) { isOK = 2; break; } WDT_HIT(); // Test if the action was cancelled if (checkbtn_cnt == 1000) { if (BUTTON_PRESS() || data_available()) { status = PM3_EOPABORTED; break; } checkbtn_cnt = 0; } ++checkbtn_cnt; // this part is from Piwi's faster nonce collecting part in Hardnested. if (!have_uid) { // need a full select cycle to get the uid first iso14a_card_select_t card_info; if (!iso14443a_select_card(uid, &card_info, &cuid, true, 0, true)) { if (DBGLEVEL >= DBG_INFO) Dbprintf("Mifare: Can't select card (ALL)"); i = 0; continue; } switch (card_info.uidlen) { case 4 : cascade_levels = 1; break; case 7 : cascade_levels = 2; break; case 10: cascade_levels = 3; break; default: i = 0; have_uid = false; continue; } have_uid = true; } else { // no need for anticollision. We can directly select the card if (!iso14443a_fast_select_card(uid, cascade_levels)) { if (DBGLEVEL >= DBG_INFO) Dbprintf("Mifare: Can't select card (UID)"); i = 0; have_uid = false; continue; } } elapsed_prng_sequences = 1; // Sending timeslot of ISO14443a frame 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 (GetCountSspClk() > sync_time) { ++elapsed_prng_sequences; 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" TAG nonce if (!ReaderReceive(receivedAnswer, receivedAnswerPar)) 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); // Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding if (ReaderReceive(receivedAnswer, receivedAnswerPar)) { received_nack = true; num_nacks++; // ALWAYS leak Detection. Well, we could be lucky and get a response nack on first try. if (i == num_nacks) { continue; } } // we didn't calibrate our clock yet, // iceman: has to be calibrated every time. if (previous_nt && !nt_attacked) { int nt_distance = dist_nt(previous_nt, nt); // if no distance between, then we are in sync. if (nt_distance == 0) { nt_attacked = nt; } else { if (nt_distance == -99999) { // invalid nonce received unexpected_random++; if (unexpected_random > MAX_UNEXPECTED_RANDOM) { // Card has an unpredictable PRNG. Give up isOK = 98; break; } else { if (sync_cycles <= 0) { sync_cycles += PRNG_SEQUENCE_LENGTH; } continue; } } if (++sync_tries > MAX_SYNC_TRIES) { isOK = 97; // Card's PRNG runs at an unexpected frequency or resets unexpectedly break; } sync_cycles = (sync_cycles - nt_distance) / elapsed_prng_sequences; if (sync_cycles <= 0) sync_cycles += PRNG_SEQUENCE_LENGTH; if (sync_cycles > PRNG_SEQUENCE_LENGTH * 2) { isOK = 96; // Card's PRNG runs at an unexpected frequency or resets unexpectedly break; } if (DBGLEVEL >= DBG_EXTENDED) Dbprintf("calibrating in cycle %d. nt_distance=%d, elapsed_prng_sequences=%d, new sync_cycles: %d\n", i, nt_distance, elapsed_prng_sequences, 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; } // average? catch_up_cycles /= elapsed_prng_sequences; if (catch_up_cycles == last_catch_up) { consecutive_resyncs++; } else { last_catch_up = catch_up_cycles; consecutive_resyncs = 0; } if (consecutive_resyncs < 3) { if (DBGLEVEL >= DBG_EXTENDED) { 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 += catch_up_cycles; if (DBGLEVEL >= DBG_EXTENDED) { 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); Dbprintf("nt [%08x] attacted [%08x]", nt, nt_attacked); } last_catch_up = 0; catch_up_cycles = 0; consecutive_resyncs = 0; } continue; } // Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding if (received_nack) catch_up_cycles = 8; // the PRNG is delayed by 8 cycles due to the NAC (4Bits = 0x05 encrypted) transfer // we are testing all 256 possibilities. par[0]++; // tried all 256 possible parities without success. if (par[0] == 0) { // did we get one NACK? if (num_nacks == 1) isOK = 1; break; } // reset the resyncs since we got a complete transaction on right time. consecutive_resyncs = 0; } // end for loop // num_nacks = number of nacks recieved. should be only 1. if not its a clone card which always sends NACK (parity == 0) ? // i = number of authentications sent. Not always 256, since we are trying to sync but close to it. uint8_t *data = BigBuf_malloc(4); data[0] = isOK; data[1] = num_nacks; num_to_bytes(i, 2, data + 2); reply_ng(CMD_HF_MIFARE_NACK_DETECT, status, data, 4); BigBuf_free(); hf_field_off(); set_tracing(false); }