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proxmark3/armsrc/iso14443a.c
iceman1001 246144df2a amiboo default pack
2020-07-08 23:11:50 +02:00

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//-----------------------------------------------------------------------------
// 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;
static uint8_t colpos = 0;
int g_rsamples = 0;
uint8_t g_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
static 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) {
g_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
static 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(void) {
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)
static tDemod14a Demod;
// Lookup-Table to decide if 4 raw bits are a modulation.
// We accept three or four "1" in any position
static 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(void) {
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.
static 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
FpgaDisableTracing();
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
//-----------------------------------------------------------------------------
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;
}
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("ToSend buffer, Out-of-bound, 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;
}
}
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 old dumps with all zero headers, we need to set default values.
for (uint8_t i = 0; i < 3; i++) {
counters[i] = le24toh(mfu_header->counter_tearing[i]);
if (mfu_header->counter_tearing[i][3] != 0x00) {
tearings[i] = mfu_header->counter_tearing[i][3];
}
}
// GET_VERSION
if (memcmp(mfu_header->version, "\x00\x00\x00\x00\x00\x00\x00\x00", 8) == 0) {
memcpy(rVERSION, "\x00\x04\x04\x02\x01\x00\x11\x03", 8);
} else {
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] = {0};
uint8_t dynamic_modulation_buffer[DYNAMIC_MODULATION_BUFFER_SIZE] = {0};
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 pack[4];
emlGetMemBt(pack, pages * 4 + MFU_DUMP_PREFIX_LENGTH, 2);
if (memcmp(pack, "\x00\x00\x00\x00", 4) == 0) {
memcpy(pack, "\x80\x80\x00\x00", 4);
}
AddCrc14A(pack, sizeof(pack) - 2);
EmSendCmd(pack, sizeof(pack));
} 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.
static 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
//-----------------------------------------------------------------------------
static 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
//-----------------------------------------------------------------------------
/*
static 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);
#if defined RDV4
AT91C_BASE_ADC->ADC_CHER = ADC_CHANNEL(ADC_CHAN_HF_RDV40);
#else
AT91C_BASE_ADC->ADC_CHER = ADC_CHANNEL(ADC_CHAN_HF);
#endif
// 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 defined RDV4
if (AT91C_BASE_ADC->ADC_SR & ADC_END_OF_CONVERSION(ADC_CHAN_HF_RDV40)) {
analogCnt++;
analogAVG += AT91C_BASE_ADC->ADC_CDR[ADC_CHAN_HF_RDV40];
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;
}
}
#else
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 * (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;
}
}
#endif
// 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);
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 (g_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);
}
static 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);
}
static 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(FPGA_MAJOR_MODE_HF_ISO14443A);
// 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)) {
iso14_pcb_blocknum = 0;
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);
FpgaDisableTracing();
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);
FpgaDisableTracing();
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);
FpgaDisableTracing();
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.
static 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);
FpgaDisableTracing();
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.
FpgaDisableTracing();
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);
}
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