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Merge branch 'master' into fix_iq_xcorr

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This commit is contained in:
pwpiwi 2018-09-12 15:14:06 +02:00
commit 9632c63767
9 changed files with 539 additions and 434 deletions
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3
armsrc/Makefile
View file

@ -59,11 +59,12 @@ THUMBSRC = start.c \
# These are to be compiled in ARM mode
ARMSRC = fpgaloader.c \
legicrf.c \
legicrfsim.c \
legic_prng.c \
$(SRC_ISO14443a) \
$(SRC_ISO14443b) \
$(SRC_CRAPTO1) \
$(SRC_CRC) \
legic_prng.c \
iclass.c \
BigBuf.c \
optimized_cipher.c \

3
armsrc/appmain.c
View file

@ -21,6 +21,7 @@
#include "printf.h"
#include "string.h"
#include "legicrf.h"
#include "legicrfsim.h"
#include "hitag2.h"
#include "hitagS.h"
#include "lfsampling.h"
@ -1090,7 +1091,7 @@ void UsbPacketReceived(uint8_t *packet, int len)
#ifdef WITH_LEGICRF
case CMD_SIMULATE_TAG_LEGIC_RF:
LegicRfSimulate(c->arg[0], c->arg[1], c->arg[2]);
LegicRfSimulate(c->arg[0]);
break;
case CMD_WRITER_LEGIC_RF:

425
armsrc/legicrf.c
View file

@ -1,7 +1,7 @@
//-----------------------------------------------------------------------------
// (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
// 2016 Iceman
// 2018 AntiCat (rwd rewritten)
// 2018 AntiCat
//
// 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
@ -20,30 +20,8 @@
#include "legic.h"
#include "crc.h"
static struct legic_frame {
int bits;
uint32_t data;
} current_frame;
static enum {
STATE_DISCON,
STATE_IV,
STATE_CON,
} legic_state;
static crc_t legic_crc;
static int legic_read_count;
static uint32_t legic_prng_bc;
static uint32_t legic_prng_iv;
static int legic_phase_drift;
static int legic_frame_drift;
static int legic_reqresp_drift;
AT91PS_TC timer;
AT91PS_TC prng_timer;
static legic_card_select_t card;/* metadata of currently selected card */
static crc_t legic_crc;
//-----------------------------------------------------------------------------
// Frame timing and pseudorandom number generator
@ -71,11 +49,6 @@ static uint32_t last_frame_end; /* ts of last bit of previews rx or tx frame */
#define TAG_BIT_PERIOD 150 /* 100us */
#define TAG_WRITE_TIMEOUT 60 /* 40 * 100us (write should take at most 3.6ms) */
#define SIM_DIVISOR 586 /* prng_time/DIV count prng needs to be forwared */
#define SIM_SHIFT 900 /* prng_time+SHIFT shift of delayed start */
#define RWD_TIME_FUZZ 20 /* rather generous 13us, since the peak detector
/+ hysteresis fuzz quite a bit */
#define LEGIC_READ 0x01 /* Read Command */
#define LEGIC_WRITE 0x00 /* Write Command */
@ -86,8 +59,6 @@ static uint32_t last_frame_end; /* ts of last bit of previews rx or tx frame */
#define INPUT_THRESHOLD 8 /* heuristically determined, lower values */
/* lead to detecting false ack during write */
#define FUZZ_EQUAL(value, target, fuzz) ((value) > ((target)-(fuzz)) && (value) < ((target)+(fuzz)))
//-----------------------------------------------------------------------------
// I/O interface abstraction (FPGA -> ARM)
//-----------------------------------------------------------------------------
@ -123,7 +94,7 @@ static inline uint16_t rx_frame_from_fpga() {
//
// The demedulated should be alligned to the bit period by the caller. This is
// done in rx_bit_as_reader and rx_ack_as_reader.
static inline bool rx_bit_as_reader() {
static inline bool rx_bit() {
int32_t sum_cq = 0;
int32_t sum_ci = 0;
@ -157,7 +128,7 @@ static inline bool rx_bit_as_reader() {
// be circumvented, but the adventage over bitbang would be little.
//-----------------------------------------------------------------------------
static inline void tx_bit_as_reader(bool bit) {
static inline void tx_bit(bool bit) {
// insert pause (modulate carrier, ssp_dout=1)
HIGH(GPIO_SSC_DOUT);
last_frame_end += RWD_TIME_PAUSE;
@ -179,7 +150,7 @@ static inline void tx_bit_as_reader(bool bit) {
// present.
//-----------------------------------------------------------------------------
static void tx_frame_as_reader(uint32_t frame, uint8_t len) {
static void tx_frame(uint32_t frame, uint8_t len) {
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX);
// wait for next tx timeslot
@ -189,7 +160,7 @@ static void tx_frame_as_reader(uint32_t frame, uint8_t len) {
// transmit frame, MSB first
for(uint8_t i = 0; i < len; ++i) {
bool bit = (frame >> i) & 0x01;
tx_bit_as_reader(bit ^ legic_prng_get_bit());
tx_bit(bit ^ legic_prng_get_bit());
legic_prng_forward(1);
};
@ -200,7 +171,7 @@ static void tx_frame_as_reader(uint32_t frame, uint8_t len) {
LOW(GPIO_SSC_DOUT);
}
static uint32_t rx_frame_as_reader(uint8_t len) {
static uint32_t rx_frame(uint8_t len) {
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR
| FPGA_HF_READER_RX_XCORR_848_KHZ
| FPGA_HF_READER_RX_XCORR_QUARTER_FREQ);
@ -210,11 +181,11 @@ static uint32_t rx_frame_as_reader(uint8_t len) {
while(GET_TICKS < last_frame_end) { };
uint32_t frame = 0;
for(uint8_t i = 0; i < len; i++) {
frame |= (rx_bit_as_reader() ^ legic_prng_get_bit()) << i;
for(uint8_t i = 0; i < len; ++i) {
frame |= (rx_bit() ^ legic_prng_get_bit()) << i;
legic_prng_forward(1);
// rx_bit_as_reader runs only 95us, resync to TAG_BIT_PERIOD
// rx_bit runs only 95us, resync to TAG_BIT_PERIOD
last_frame_end += TAG_BIT_PERIOD;
while(GET_TICKS < last_frame_end) { };
}
@ -222,7 +193,7 @@ static uint32_t rx_frame_as_reader(uint8_t len) {
return frame;
}
static bool rx_ack_as_reader() {
static bool rx_ack() {
// change fpga into rx mode
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR
| FPGA_HF_READER_RX_XCORR_848_KHZ
@ -235,10 +206,10 @@ static bool rx_ack_as_reader() {
uint32_t ack = 0;
for(uint8_t i = 0; i < TAG_WRITE_TIMEOUT; ++i) {
// sample bit
ack = rx_bit_as_reader();
ack = rx_bit();
legic_prng_forward(1);
// rx_bit_as_reader runs only 95us, resync to TAG_BIT_PERIOD
// rx_bit runs only 95us, resync to TAG_BIT_PERIOD
last_frame_end += TAG_BIT_PERIOD;
while(GET_TICKS < last_frame_end) { };
@ -255,7 +226,7 @@ static bool rx_ack_as_reader() {
// Legic Reader
//-----------------------------------------------------------------------------
int init_card(uint8_t cardtype, legic_card_select_t *p_card) {
static int init_card(uint8_t cardtype, legic_card_select_t *p_card) {
p_card->tagtype = cardtype;
switch(p_card->tagtype) {
@ -312,8 +283,8 @@ static void init_reader(bool clear_mem) {
// The setup consists of a three way handshake:
// - Transmit initialisation vector 7 bits
// - Receive card type 6 bits
// - Acknowledge frame 6 bits
static uint32_t setup_phase_reader(uint8_t iv) {
// - Transmit Acknowledge 6 bits
static uint32_t setup_phase(uint8_t iv) {
// init coordination timestamp
last_frame_end = GET_TICKS;
@ -322,24 +293,24 @@ static uint32_t setup_phase_reader(uint8_t iv) {
while(GET_TICKS < last_frame_end) { };
legic_prng_init(0);
tx_frame_as_reader(iv, 7);
tx_frame(iv, 7);
// configure iv
// configure prng
legic_prng_init(iv);
legic_prng_forward(2);
// receive card type
int32_t card_type = rx_frame_as_reader(6);
int32_t card_type = rx_frame(6);
legic_prng_forward(3);
// send obsfuscated acknowledgment frame
switch (card_type) {
case 0x0D:
tx_frame_as_reader(0x19, 6); // MIM22 | READCMD = 0x18 | 0x01
tx_frame(0x19, 6); // MIM22 | READCMD = 0x18 | 0x01
break;
case 0x1D:
case 0x3D:
tx_frame_as_reader(0x39, 6); // MIM256 | READCMD = 0x38 | 0x01
tx_frame(0x39, 6); // MIM256 | READCMD = 0x38 | 0x01
break;
}
@ -358,9 +329,9 @@ static int16_t read_byte(uint16_t index, uint8_t cmd_sz) {
// read one byte
LED_B_ON();
legic_prng_forward(2);
tx_frame_as_reader(cmd, cmd_sz);
tx_frame(cmd, cmd_sz);
legic_prng_forward(2);
uint32_t frame = rx_frame_as_reader(12);
uint32_t frame = rx_frame(12);
LED_B_OFF();
// split frame into data and crc
@ -390,12 +361,12 @@ bool write_byte(uint16_t index, uint8_t byte, uint8_t addr_sz) {
// send write command
LED_C_ON();
legic_prng_forward(2);
tx_frame_as_reader(cmd, addr_sz + 1 + 8 + 4); // sz = addr_sz + cmd + data + crc
tx_frame(cmd, addr_sz + 1 + 8 + 4); // sz = addr_sz + cmd + data + crc
legic_prng_forward(3);
LED_C_OFF();
// wait for ack
return rx_ack_as_reader();
return rx_ack();
}
//-----------------------------------------------------------------------------
@ -412,7 +383,7 @@ void LegicRfReader(int offset, int bytes) {
// establish shared secret and detect card type
DbpString("Reading card ...");
uint8_t card_type = setup_phase_reader(SESSION_IV);
uint8_t card_type = setup_phase(SESSION_IV);
if(init_card(card_type, &card) != 0) {
Dbprintf("No or unknown card found, aborting");
goto OUT;
@ -462,7 +433,7 @@ void LegicRfWriter(int bytes, int offset) {
// establish shared secret and detect card type
Dbprintf("Writing 0x%02.2x - 0x%02.2x ...", offset, offset+bytes);
uint8_t card_type = setup_phase_reader(SESSION_IV);
uint8_t card_type = setup_phase(SESSION_IV);
if(init_card(card_type, &card) != 0) {
Dbprintf("No or unknown card found, aborting");
goto OUT;
@ -491,345 +462,3 @@ OUT:
LED_D_OFF();
StopTicks();
}
//-----------------------------------------------------------------------------
// Legic Simulator
//-----------------------------------------------------------------------------
static void setup_timer(void)
{
/* Set up Timer 1 to use for measuring time between pulses. Since we're bit-banging
* this it won't be terribly accurate but should be good enough.
*/
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
timer = AT91C_BASE_TC1;
timer->TC_CCR = AT91C_TC_CLKDIS;
timer->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK;
timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
/*
* Set up Timer 2 to use for measuring time between frames in
* tag simulation mode. Runs 4x faster as Timer 1
*/
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC2);
prng_timer = AT91C_BASE_TC2;
prng_timer->TC_CCR = AT91C_TC_CLKDIS;
prng_timer->TC_CMR = AT91C_TC_CLKS_TIMER_DIV2_CLOCK;
prng_timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
}
/* Generate Keystream */
static uint32_t get_key_stream(int skip, int count)
{
uint32_t key=0; int i;
/* Use int to enlarge timer tc to 32bit */
legic_prng_bc += prng_timer->TC_CV;
prng_timer->TC_CCR = AT91C_TC_SWTRG;
/* If skip == -1, forward prng time based */
if(skip == -1) {
i = (legic_prng_bc+SIM_SHIFT)/SIM_DIVISOR; /* Calculate Cycles based on timer */
i -= legic_prng_count(); /* substract cycles of finished frames */
i -= count; /* substract current frame length, rewidn to bedinning */
legic_prng_forward(i);
} else {
legic_prng_forward(skip);
}
/* Write Time Data into LOG */
uint8_t *BigBuf = BigBuf_get_addr();
if(count == 6) { i = -1; } else { i = legic_read_count; }
BigBuf[OFFSET_LOG+128+i] = legic_prng_count();
BigBuf[OFFSET_LOG+256+i*4] = (legic_prng_bc >> 0) & 0xff;
BigBuf[OFFSET_LOG+256+i*4+1] = (legic_prng_bc >> 8) & 0xff;
BigBuf[OFFSET_LOG+256+i*4+2] = (legic_prng_bc >>16) & 0xff;
BigBuf[OFFSET_LOG+256+i*4+3] = (legic_prng_bc >>24) & 0xff;
BigBuf[OFFSET_LOG+384+i] = count;
/* Generate KeyStream */
for(i=0; i<count; i++) {
key |= legic_prng_get_bit() << i;
legic_prng_forward(1);
}
return key;
}
/* Send a frame in tag mode, the FPGA must have been set up by
* LegicRfSimulate
*/
static void frame_send_tag(uint16_t response, int bits, int crypt)
{
/* Bitbang the response */
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
/* Use time to crypt frame */
if(crypt) {
legic_prng_forward(2); /* TAG_TIME_WAIT -> shift by 2 */
int i; int key = 0;
for(i=0; i<bits; i++) {
key |= legic_prng_get_bit() << i;
legic_prng_forward(1);
}
//Dbprintf("key = 0x%x", key);
response = response ^ key;
}
/* Wait for the frame start */
while(timer->TC_CV < (TAG_FRAME_WAIT - 30)) ;
int i;
for(i=0; i<bits; i++) {
int nextbit = timer->TC_CV + TAG_BIT_PERIOD;
int bit = response & 1;
response = response >> 1;
if(bit) {
AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
} else {
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
}
while(timer->TC_CV < nextbit) ;
}
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
}
static void frame_append_bit(struct legic_frame * const f, int bit)
{
if(f->bits >= 31) {
return; /* Overflow, won't happen */
}
f->data |= (bit<<f->bits);
f->bits++;
}
static void frame_clean(struct legic_frame * const f)
{
f->data = 0;
f->bits = 0;
}
/* Handle (whether to respond) a frame in tag mode */
static void frame_handle_tag(struct legic_frame const * const f)
{
uint8_t *BigBuf = BigBuf_get_addr();
/* First Part of Handshake (IV) */
if(f->bits == 7) {
if(f->data == SESSION_IV) {
LED_C_ON();
prng_timer->TC_CCR = AT91C_TC_SWTRG;
legic_prng_init(f->data);
frame_send_tag(0x3d, 6, 1); /* 0x3d^0x26 = 0x1b */
legic_state = STATE_IV;
legic_read_count = 0;
legic_prng_bc = 0;
legic_prng_iv = f->data;
/* TIMEOUT */
timer->TC_CCR = AT91C_TC_SWTRG;
while(timer->TC_CV > 1);
while(timer->TC_CV < 280);
return;
} else if((prng_timer->TC_CV % 50) > 40) {
legic_prng_init(f->data);
frame_send_tag(0x3d, 6, 1);
SpinDelay(20);
return;
}
}
/* 0x19==??? */
if(legic_state == STATE_IV) {
if((f->bits == 6) && (f->data == (0x19 ^ get_key_stream(1, 6)))) {
legic_state = STATE_CON;
/* TIMEOUT */
timer->TC_CCR = AT91C_TC_SWTRG;
while(timer->TC_CV > 1);
while(timer->TC_CV < 200);
return;
} else {
legic_state = STATE_DISCON;
LED_C_OFF();
Dbprintf("0x19 - Frame: %03.3x", f->data);
return;
}
}
/* Read */
if(f->bits == 11) {
if(legic_state == STATE_CON) {
int key = get_key_stream(-1, 11); //legic_phase_drift, 11);
int addr = f->data ^ key; addr = addr >> 1;
int data = BigBuf[addr];
int hash = calc_crc4(addr, data, 11) << 8;
BigBuf[OFFSET_LOG+legic_read_count] = (uint8_t)addr;
legic_read_count++;
//Dbprintf("Data:%03.3x, key:%03.3x, addr: %03.3x, read_c:%u", f->data, key, addr, read_c);
legic_prng_forward(legic_reqresp_drift);
frame_send_tag(hash | data, 12, 1);
/* SHORT TIMEOUT */
timer->TC_CCR = AT91C_TC_SWTRG;
while(timer->TC_CV > 1);
legic_prng_forward(legic_frame_drift);
while(timer->TC_CV < 180);
return;
}
}
/* Write */
if(f->bits == 23) {
int key = get_key_stream(-1, 23); //legic_frame_drift, 23);
int addr = f->data ^ key; addr = addr >> 1; addr = addr & 0x3ff;
int data = f->data ^ key; data = data >> 11; data = data & 0xff;
/* write command */
legic_state = STATE_DISCON;
LED_C_OFF();
Dbprintf("write - addr: %x, data: %x", addr, data);
return;
}
if(legic_state != STATE_DISCON) {
Dbprintf("Unexpected: sz:%u, Data:%03.3x, State:%u, Count:%u", f->bits, f->data, legic_state, legic_read_count);
int i;
Dbprintf("IV: %03.3x", legic_prng_iv);
for(i = 0; i<legic_read_count; i++) {
Dbprintf("Read Nb: %u, Addr: %u", i, BigBuf[OFFSET_LOG+i]);
}
for(i = -1; i<legic_read_count; i++) {
uint32_t t;
t = BigBuf[OFFSET_LOG+256+i*4];
t |= BigBuf[OFFSET_LOG+256+i*4+1] << 8;
t |= BigBuf[OFFSET_LOG+256+i*4+2] <<16;
t |= BigBuf[OFFSET_LOG+256+i*4+3] <<24;
Dbprintf("Cycles: %u, Frame Length: %u, Time: %u",
BigBuf[OFFSET_LOG+128+i],
BigBuf[OFFSET_LOG+384+i],
t);
}
}
legic_state = STATE_DISCON;
legic_read_count = 0;
SpinDelay(10);
LED_C_OFF();
return;
}
/* Read bit by bit untill full frame is received
* Call to process frame end answer
*/
static void emit(int bit)
{
if(bit == -1) {
if(current_frame.bits <= 4) {
frame_clean(&current_frame);
} else {
frame_handle_tag(&current_frame);
frame_clean(&current_frame);
}
WDT_HIT();
} else if(bit == 0) {
frame_append_bit(&current_frame, 0);
} else if(bit == 1) {
frame_append_bit(&current_frame, 1);
}
}
void LegicRfSimulate(int phase, int frame, int reqresp)
{
/* ADC path high-frequency peak detector, FPGA in high-frequency simulator mode,
* modulation mode set to 212kHz subcarrier. We are getting the incoming raw
* envelope waveform on DIN and should send our response on DOUT.
*
* The LEGIC RF protocol is pulse-pause-encoding from reader to card, so we'll
* measure the time between two rising edges on DIN, and no encoding on the
* subcarrier from card to reader, so we'll just shift out our verbatim data
* on DOUT, 1 bit is 100us. The time from reader to card frame is still unclear,
* seems to be 300us-ish.
*/
if(phase < 0) {
int i;
for(i=0; i<=reqresp; i++) {
legic_prng_init(SESSION_IV);
Dbprintf("i=%u, key 0x%3.3x", i, get_key_stream(i, frame));
}
return;
}
legic_phase_drift = phase;
legic_frame_drift = frame;
legic_reqresp_drift = reqresp;
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
FpgaSetupSsc(FPGA_MAJOR_MODE_HF_SIMULATOR);
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_212K);
/* Bitbang the receiver */
AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
setup_timer();
crc_init(&legic_crc, 4, 0x19 >> 1, 0x5, 0);
int old_level = 0;
int active = 0;
legic_state = STATE_DISCON;
LED_B_ON();
DbpString("Starting Legic emulator, press button to end");
while(!BUTTON_PRESS()) {
int level = !!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
int time = timer->TC_CV;
if(level != old_level) {
if(level == 1) {
timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
if(FUZZ_EQUAL(time, RWD_TIME_1, RWD_TIME_FUZZ)) {
/* 1 bit */
emit(1);
active = 1;
LED_A_ON();
} else if(FUZZ_EQUAL(time, RWD_TIME_0, RWD_TIME_FUZZ)) {
/* 0 bit */
emit(0);
active = 1;
LED_A_ON();
} else if(active) {
/* invalid */
emit(-1);
active = 0;
LED_A_OFF();
}
}
}
if(time >= (RWD_TIME_1+RWD_TIME_FUZZ) && active) {
/* Frame end */
emit(-1);
active = 0;
LED_A_OFF();
}
if(time >= (20*RWD_TIME_1) && (timer->TC_SR & AT91C_TC_CLKSTA)) {
timer->TC_CCR = AT91C_TC_CLKDIS;
}
old_level = level;
WDT_HIT();
}
DbpString("Stopped");
LED_B_OFF();
LED_A_OFF();
LED_C_OFF();
}

2
armsrc/legicrf.h
View file

@ -1,5 +1,6 @@
//-----------------------------------------------------------------------------
// (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
// 2018 AntiCat
//
// 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
@ -11,7 +12,6 @@
#ifndef __LEGICRF_H
#define __LEGICRF_H
extern void LegicRfSimulate(int phase, int frame, int reqresp);
extern void LegicRfReader(int bytes, int offset);
extern void LegicRfWriter(int bytes, int offset);

469
armsrc/legicrfsim.c Normal file
View file

@ -0,0 +1,469 @@
//-----------------------------------------------------------------------------
// (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
// 2016 Iceman
// 2018 AntiCat
//
// 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.
//-----------------------------------------------------------------------------
// LEGIC RF simulation code
//-----------------------------------------------------------------------------
#include "proxmark3.h"
#include "apps.h"
#include "util.h"
#include "string.h"
#include "legicrfsim.h"
#include "legic_prng.h"
#include "legic.h"
#include "crc.h"
#include "usb_cdc.h" // for usb_poll_validate_length
static uint8_t* legic_mem; /* card memory, used for sim */
static legic_card_select_t card;/* metadata of currently selected card */
static crc_t legic_crc;
//-----------------------------------------------------------------------------
// Frame timing and pseudorandom number generator
//
// The Prng is forwarded every 99.1us (TAG_BIT_PERIOD), except when the reader is
// transmitting. In that case the prng has to be forwarded every bit transmitted:
// - 31.3us for a 0 (RWD_TIME_0)
// - 99.1us for a 1 (RWD_TIME_1)
//
// The data dependent timing makes writing comprehensible code significantly
// harder. The current aproach forwards the prng data based if there is data on
// air and time based, using GetCountSspClk(), during computational and wait
// periodes. SSP Clock is clocked by the FPGA at 212 kHz (subcarrier frequency).
//
// To not have the necessity to calculate/guess exection time dependend timeouts
// tx_frame and rx_frame use a shared timestamp to coordinate tx and rx timeslots.
//-----------------------------------------------------------------------------
static uint32_t last_frame_end; /* ts of last bit of previews rx or tx frame */
#define TAG_FRAME_WAIT 70 /* 330us from READER frame end to TAG frame start */
#define TAG_ACK_WAIT 758 /* 3.57ms from READER frame end to TAG write ACK */
#define TAG_BIT_PERIOD 21 /* 99.1us */
#define RWD_TIME_PAUSE 4 /* 18.9us */
#define RWD_TIME_1 21 /* RWD_TIME_PAUSE 18.9us off + 80.2us on = 99.1us */
#define RWD_TIME_0 13 /* RWD_TIME_PAUSE 18.9us off + 42.4us on = 61.3us */
#define RWD_CMD_TIMEOUT 40 /* 40 * 99.1us (arbitrary value) */
#define RWD_MIN_FRAME_LEN 6 /* Shortest frame is 6 bits */
#define RWD_MAX_FRAME_LEN 23 /* Longest frame is 23 bits */
#define RWD_PULSE 1 /* Pulse is signaled with GPIO_SSC_DIN high */
#define RWD_PAUSE 0 /* Pause is signaled with GPIO_SSC_DIN low */
//-----------------------------------------------------------------------------
// Demodulation
//-----------------------------------------------------------------------------
// Returns true if a pulse/pause is received within timeout
static inline bool wait_for(bool value, const uint32_t timeout) {
while((bool)(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN) != value) {
if(GetCountSspClk() > timeout) {
return false;
}
}
return true;
}
// Returns a demedulated bit or -1 on code violation
//
// rx_bit decodes bits using a thresholds. rx_bit has to be called by as soon as
// a frame starts (first pause is received). rx_bit checks for a pause up to
// 18.9us followed by a pulse of 80.2us or 42.4us:
// - A bit length <18.9us is a code violation
// - A bit length >80.2us is a 1
// - A bit length <80.2us is a 0
// - A bit length >148.6us is a code violation
static inline int8_t rx_bit() {
// backup ts for threshold calculation
uint32_t bit_start = last_frame_end;
// wait for pause to end
if(!wait_for(RWD_PULSE, bit_start + RWD_TIME_1*3/2)) {
return -1;
}
// wait for next pause
if(!wait_for(RWD_PAUSE, bit_start + RWD_TIME_1*3/2)) {
return -1;
}
// update bit and frame end
last_frame_end = GetCountSspClk();
// check for code violation (bit to short)
if(last_frame_end - bit_start < RWD_TIME_PAUSE) {
return -1;
}
// apply threshold (average of RWD_TIME_0 and )
return (last_frame_end - bit_start > (RWD_TIME_0 + RWD_TIME_1) / 2);
}
//-----------------------------------------------------------------------------
// Modulation
//
// LEGIC RF uses a very basic load modulation from card to reader:
// - Subcarrier on for a 1
// - Subcarrier off for for a 0
//
// The 212kHz subcarrier is generated by the FPGA as well as a mathcing ssp clk.
// Each bit is transfered in a 99.1us slot and the first timeslot starts 330us
// after the final 20us pause generated by the reader.
//-----------------------------------------------------------------------------
// Transmits a bit
//
// Note: The Subcarrier is not disabled during bits to prevent glitches. This is
// not mandatory but results in a cleaner signal. tx_frame will disable
// the subcarrier when the frame is done.
static inline void tx_bit(bool bit) {
LED_C_ON();
if(bit) {
// modulate subcarrier
HIGH(GPIO_SSC_DOUT);
} else {
// do not modulate subcarrier
LOW(GPIO_SSC_DOUT);
}
// wait for tx timeslot to end
last_frame_end += TAG_BIT_PERIOD;
while(GetCountSspClk() < last_frame_end) { };
LED_C_OFF();
}
//-----------------------------------------------------------------------------
// Frame Handling
//
// The LEGIC RF protocol from reader to card does not include explicit frame
// start/stop information or length information. The tag detects end of frame
// trough an extended pulse (>99.1us) without a pause.
// In reverse direction (card to reader) the number of bites is well known
// and depends only the command received (IV, ACK, READ or WRITE).
//-----------------------------------------------------------------------------
static void tx_frame(uint32_t frame, uint8_t len) {
// wait for next tx timeslot
last_frame_end += TAG_FRAME_WAIT;
legic_prng_forward(TAG_FRAME_WAIT/TAG_BIT_PERIOD - 1);
while(GetCountSspClk() < last_frame_end) { };
// transmit frame, MSB first
for(uint8_t i = 0; i < len; ++i) {
bool bit = (frame >> i) & 0x01;
tx_bit(bit ^ legic_prng_get_bit());
legic_prng_forward(1);
};
// disable subcarrier
LOW(GPIO_SSC_DOUT);
}
static void tx_ack() {
// wait for ack timeslot
last_frame_end += TAG_ACK_WAIT;
legic_prng_forward(TAG_ACK_WAIT/TAG_BIT_PERIOD - 1);
while(GetCountSspClk() < last_frame_end) { };
// transmit ack (ack is not encrypted)
tx_bit(true);
legic_prng_forward(1);
// disable subcarrier
LOW(GPIO_SSC_DOUT);
}
// Returns a demedulated frame or -1 on code violation
//
// Since TX to RX delay is arbitrary rx_frame has to:
// - detect start of frame (first pause)
// - forward prng based on ts/TAG_BIT_PERIOD
// - receive the frame
// - detect end of frame (last pause)
static int32_t rx_frame(uint8_t *len) {
int32_t frame = 0;
// add 2 SSP clock cycles (1 for tx and 1 for rx pipeline delay)
// those will be substracted at the end of the rx phase
last_frame_end -= 2;
// wait for first pause (start of frame)
for(uint8_t i = 0; true; ++i) {
// increment prng every TAG_BIT_PERIOD
last_frame_end += TAG_BIT_PERIOD;
legic_prng_forward(1);
// if start of frame was received exit delay loop
if(wait_for(RWD_PAUSE, last_frame_end)) {
last_frame_end = GetCountSspClk();
break;
}
// check for code violation
if(i > RWD_CMD_TIMEOUT) {
return -1;
}
}
// receive frame
for(*len = 0; true; ++(*len)) {
// receive next bit
LED_D_ON();
int8_t bit = rx_bit();
LED_D_OFF();
// check for code violation and to short / long frame
if((bit < 0) && ((*len < RWD_MIN_FRAME_LEN) || (*len > RWD_MAX_FRAME_LEN))) {
return -1;
}
// check for code violation caused by end of frame
if(bit < 0) {
break;
}
// append bit
frame |= (bit ^ legic_prng_get_bit()) << (*len);
legic_prng_forward(1);
}
// rx_bit sets coordination timestamp to start of pause, append pause duration
// and substract 2 SSP clock cycles (1 for rx and 1 for tx pipeline delay) to
// obtain exact end of frame.
last_frame_end += RWD_TIME_PAUSE - 2;
return frame;
}
//-----------------------------------------------------------------------------
// Legic Simulator
//-----------------------------------------------------------------------------
static int32_t init_card(uint8_t cardtype, legic_card_select_t *p_card) {
p_card->tagtype = cardtype;
switch(p_card->tagtype) {
case 0:
p_card->cmdsize = 6;
p_card->addrsize = 5;
p_card->cardsize = 22;
break;
case 1:
p_card->cmdsize = 9;
p_card->addrsize = 8;
p_card->cardsize = 256;
break;
case 2:
p_card->cmdsize = 11;
p_card->addrsize = 10;
p_card->cardsize = 1024;
break;
default:
p_card->cmdsize = 0;
p_card->addrsize = 0;
p_card->cardsize = 0;
return 2;
}
return 0;
}
static void init_tag() {
// configure FPGA
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR
| FPGA_HF_SIMULATOR_MODULATE_212K);
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
// configure SSC with defaults
FpgaSetupSsc(FPGA_MAJOR_MODE_HF_SIMULATOR);
// first pull output to low to prevent glitches then re-claim GPIO_SSC_DOUT
LOW(GPIO_SSC_DOUT);
AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
// reserve a cardmem, meaning we can use the tracelog function in bigbuff easier.
legic_mem = BigBuf_get_addr();
// init crc calculator
crc_init(&legic_crc, 4, 0x19 >> 1, 0x05, 0);
// start 212kHz timer (running from SSP Clock)
StartCountSspClk();
}
// Setup reader to card connection
//
// The setup consists of a three way handshake:
// - Receive initialisation vector 7 bits
// - Transmit card type 6 bits
// - Receive Acknowledge 6 bits
static int32_t setup_phase(legic_card_select_t *p_card) {
uint8_t len = 0;
// init coordination timestamp
last_frame_end = GetCountSspClk();
// reset prng
legic_prng_init(0);
// wait for iv
int32_t iv = rx_frame(&len);
if((len != 7) || (iv < 0)) {
return -1;
}
// configure prng
legic_prng_init(iv);
// reply with card type
switch(p_card->tagtype) {
case 0:
tx_frame(0x0D, 6);
break;
case 1:
tx_frame(0x1D, 6);
break;
case 2:
tx_frame(0x3D, 6);
break;
}
// wait for ack
int32_t ack = rx_frame(&len);
if((len != 6) || (ack < 0)) {
return -1;
}
// validate data
switch(p_card->tagtype) {
case 0:
if(ack != 0x19) return -1;
break;
case 1:
if(ack != 0x39) return -1;
break;
case 2:
if(ack != 0x39) return -1;
break;
}
// During rx the prng is clocked using the variable reader period.
// Since rx_frame detects end of frame by detecting a code violation,
// the prng is off by one bit period after each rx phase. Hence, tx
// code advances the prng by (TAG_FRAME_WAIT/TAG_BIT_PERIOD - 1).
// This is not possible for back to back rx, so this quirk reduces
// the gap by one period.
last_frame_end += TAG_BIT_PERIOD;
return 0;
}
static uint8_t calc_crc4(uint16_t cmd, uint8_t cmd_sz, uint8_t value) {
crc_clear(&legic_crc);
crc_update(&legic_crc, (value << cmd_sz) | cmd, 8 + cmd_sz);
return crc_finish(&legic_crc);
}
static int32_t connected_phase(legic_card_select_t *p_card) {
uint8_t len = 0;
// wait for command
int32_t cmd = rx_frame(&len);
if(cmd < 0) {
return -1;
}
// check if command is LEGIC_READ
if(len == p_card->cmdsize) {
// prepare data
uint8_t byte = legic_mem[cmd >> 1];
uint8_t crc = calc_crc4(cmd, p_card->cmdsize, byte);
// transmit data
tx_frame((crc << 8) | byte, 12);
return 0;
}
// check if command is LEGIC_WRITE
if(len == p_card->cmdsize + 8 + 4) {
// decode data
uint16_t mask = (1 << p_card->addrsize) - 1;
uint16_t addr = (cmd >> 1) & mask;
uint8_t byte = (cmd >> p_card->cmdsize) & 0xff;
uint8_t crc = (cmd >> (p_card->cmdsize + 8)) & 0xf;
// check received against calculated crc
uint8_t calc_crc = calc_crc4(addr << 1, p_card->cmdsize, byte);
if(calc_crc != crc) {
Dbprintf("!!! crc mismatch: %x != %x !!!", calc_crc, crc);
return -1;
}
// store data
legic_mem[addr] = byte;
// transmit ack
tx_ack();
return 0;
}
return -1;
}
//-----------------------------------------------------------------------------
// Command Line Interface
//
// Only this function is public / called from appmain.c
//-----------------------------------------------------------------------------
void LegicRfSimulate(uint8_t cardtype) {
// configure ARM and FPGA
init_tag();
// verify command line input
if(init_card(cardtype, &card) != 0) {
DbpString("Unknown tagtype.");
goto OUT;
}
LED_A_ON();
DbpString("Starting Legic emulator, press button to end");
while(!BUTTON_PRESS() && !usb_poll_validate_length()) {
WDT_HIT();
// wait for carrier, restart after timeout
if(!wait_for(RWD_PULSE, GetCountSspClk() + TAG_BIT_PERIOD)) {
continue;
}
// wait for connection, restart on error
if(setup_phase(&card)) {
continue;
}
// conection is established, process commands until one fails
while(!connected_phase(&card)) {
WDT_HIT();
}
}
OUT:
DbpString("Stopped");
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
LED_A_OFF();
LED_C_OFF();
LED_D_OFF();
StopTicks();
}

19
armsrc/legicrfsim.h Normal file
View file

@ -0,0 +1,19 @@
//-----------------------------------------------------------------------------
// (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
// 2018 AntiCat
//
// 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.
//-----------------------------------------------------------------------------
// LEGIC RF emulation public interface
//-----------------------------------------------------------------------------
#ifndef __LEGICRFSIM_H
#define __LEGICRFSIM_H
#include "proxmark3.h"
extern void LegicRfSimulate(uint8_t tagtype);
#endif /* __LEGICRFSIM_H */

8
client/cmdhflegic.c
View file

@ -28,7 +28,7 @@ static command_t CommandTable[] =
{"reader", CmdLegicRFRead, 0, "[offset [length]] -- read bytes from a LEGIC card"},
{"save", CmdLegicSave, 0, "<filename> [<length>] -- Store samples"},
{"load", CmdLegicLoad, 0, "<filename> -- Restore samples"},
{"sim", CmdLegicRfSim, 0, "[phase drift [frame drift [req/resp drift]]] Start tag simulator (use after load or read)"},
{"sim", CmdLegicRfSim, 0, "[tagtype, 0:MIM22, 1:MIM256, 2:MIM1024] Start tag simulator (use after load or read)"},
{"write", CmdLegicRfWrite,0, "<offset> <length> -- Write sample buffer (user after load or read)"},
{"fill", CmdLegicRfFill, 0, "<offset> <length> <value> -- Fill/Write tag with constant value"},
{NULL, NULL, 0, NULL}
@ -320,10 +320,8 @@ int CmdLegicSave(const char *Cmd)
int CmdLegicRfSim(const char *Cmd)
{
UsbCommand c={CMD_SIMULATE_TAG_LEGIC_RF};
c.arg[0] = 6;
c.arg[1] = 3;
c.arg[2] = 0;
sscanf(Cmd, " %" SCNi64 " %" SCNi64 " %" SCNi64, &c.arg[0], &c.arg[1], &c.arg[2]);
c.arg[0] = 1;
sscanf(Cmd, " %" SCNi64, &c.arg[0]);
SendCommand(&c);
return 0;
}

BIN
fpga/fpga_hf.bit
View file

Binary file not shown.

44
fpga/hi_simulate.v
View file

@ -51,38 +51,29 @@ begin
end
// Divide 13.56 MHz by 32 to produce the SSP_CLK
// The register is bigger to allow higher division factors of up to /128
// Divide 13.56 MHz to produce various frequencies for SSP_CLK
// and modulation. 11 bits allow for factors of up to /128.
reg [10:0] ssp_clk_divider;
always @(posedge adc_clk)
ssp_clk_divider <= (ssp_clk_divider + 1);
reg ssp_clk;
reg ssp_frame;
always @(negedge adc_clk)
begin
//If we're in 101, we only need a new bit every 8th carrier bit (53Hz). Otherwise, get next bit at 424Khz
if(mod_type == 3'b101)
begin
if(ssp_clk_divider[7:0] == 8'b00000000)
ssp_clk <= 1'b0;
if(ssp_clk_divider[7:0] == 8'b10000000)
ssp_clk <= 1'b1;
end
// Get bit every at 53KHz (every 8th carrier bit of 424kHz)
ssp_clk <= ssp_clk_divider[7];
else if(mod_type == 3'b010)
// Get next bit at 212kHz
ssp_clk <= ssp_clk_divider[5];
else
begin
if(ssp_clk_divider[4:0] == 5'd0)//[4:0] == 5'b00000)
ssp_clk <= 1'b1;
if(ssp_clk_divider[4:0] == 5'd16) //[4:0] == 5'b10000)
ssp_clk <= 1'b0;
end
// Get next bit at 424Khz
ssp_clk <= ssp_clk_divider[4];
end
//assign ssp_clk = ssp_clk_divider[4];
// Divide SSP_CLK by 8 to produce the byte framing signal; the phase of
// this is arbitrary, because it's just a bitstream.
// One nasty issue, though: I can't make it work with both rx and tx at
@ -96,19 +87,19 @@ always @(negedge ssp_clk)
ssp_frame_divider_from_arm <= (ssp_frame_divider_from_arm + 1);
reg ssp_frame;
always @(ssp_frame_divider_to_arm or ssp_frame_divider_from_arm or mod_type)
if(mod_type == 3'b000) // not modulating, so listening, to ARM
ssp_frame = (ssp_frame_divider_to_arm == 3'b000);
else
ssp_frame = (ssp_frame_divider_from_arm == 3'b000);
ssp_frame = (ssp_frame_divider_from_arm == 3'b000);
// Synchronize up the after-hysteresis signal, to produce DIN.
reg ssp_din;
always @(posedge ssp_clk)
ssp_din = after_hysteresis;
// Modulating carrier frequency is fc/16, reuse ssp_clk divider for that
// Modulating carrier frequency is fc/64 (212kHz) to fc/16 (848kHz). Reuse ssp_clk divider for that.
reg modulating_carrier;
always @(mod_type or ssp_clk or ssp_dout)
if(mod_type == 3'b000)
@ -116,9 +107,9 @@ always @(mod_type or ssp_clk or ssp_dout)
else if(mod_type == 3'b001)
modulating_carrier <= ssp_dout ^ ssp_clk_divider[3]; // XOR means BPSK
else if(mod_type == 3'b010)
modulating_carrier <= ssp_dout & ssp_clk_divider[5]; // switch 212kHz subcarrier on/off
modulating_carrier <= ssp_dout & ssp_clk_divider[5]; // switch 212kHz subcarrier on/off
else if(mod_type == 3'b100 || mod_type == 3'b101)
modulating_carrier <= ssp_dout & ssp_clk_divider[4]; // switch 424kHz modulation on/off
modulating_carrier <= ssp_dout & ssp_clk_divider[4]; // switch 424kHz modulation on/off
else
modulating_carrier <= 1'b0; // yet unused
@ -133,9 +124,6 @@ assign pwr_oe4 = modulating_carrier;
// This one is always on, so that we can watch the carrier.
assign pwr_oe3 = 1'b0;
assign dbg = modulating_carrier;
//reg dbg;
//always @(ssp_dout)
// dbg <= ssp_dout;
assign dbg = ssp_din;
endmodule