revert command offsets now leading spaces have been stripped (thanks iZsh!)

[proxmark3-svn] / armsrc / legicrf.c

diff --git a/armsrc/legicrf.c b/armsrc/legicrf.c
index 86c0c3604f1b6074e1f07f0aaf74d367b12910b7..313ac3c95c0bb4aac6d5e3564cafe4ef221345b4 100644 (file)
--- a/armsrc/legicrf.c
+++ b/armsrc/legicrf.c
@@ -1,20 +1,29 @@
-/*
- * LEGIC RF simulation code
- *  
- * (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
- */
-
-#include <proxmark3.h>
+//-----------------------------------------------------------------------------
+// (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
+//
+// 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 "apps.h"

+#include "util.h"
+#include "string.h"
+

 #include "legicrf.h"
 #include "legicrf.h"

-#include "unistd.h"
-#include "stdint.h"
+#include "legic_prng.h"
+#include "crc.h"

 
 static struct legic_frame {
        int bits;
 
 static struct legic_frame {
        int bits;

-       uint16_t data;
+       uint32_t data;

 } current_frame;
 } current_frame;

+
+static crc_t legic_crc;
+

 AT91PS_TC timer;
 
 static void setup_timer(void)
 AT91PS_TC timer;
 
 static void setup_timer(void)


@@ -25,7 +34,7 @@ static void setup_timer(void)
        AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
        timer = AT91C_BASE_TC1;
        timer->TC_CCR = AT91C_TC_CLKDIS;
        AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
        timer = AT91C_BASE_TC1;
        timer->TC_CCR = AT91C_TC_CLKDIS;

-       timer->TC_CMR = TC_CMR_TCCLKS_TIMER_CLOCK3;
+       timer->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK;

        timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
 
 /* At TIMER_CLOCK3 (MCK/32) */
        timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
 
 /* At TIMER_CLOCK3 (MCK/32) */


@@ -43,33 +52,35 @@ static void setup_timer(void)
 /* Send a frame in reader mode, the FPGA must have been set up by
  * LegicRfReader
  */
 /* Send a frame in reader mode, the FPGA must have been set up by
  * LegicRfReader
  */

-static void frame_send_rwd(uint16_t data, int bits)
+static void frame_send_rwd(uint32_t data, int bits)

 {
        /* Start clock */
        timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
        while(timer->TC_CV > 1) ; /* Wait till the clock has reset */
 {
        /* Start clock */
        timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
        while(timer->TC_CV > 1) ; /* Wait till the clock has reset */

-       
+

        int i;
        for(i=0; i<bits; i++) {
                int starttime = timer->TC_CV;
                int pause_end = starttime + RWD_TIME_PAUSE, bit_end;
                int bit = data & 1;
                data = data >> 1;
        int i;
        for(i=0; i<bits; i++) {
                int starttime = timer->TC_CV;
                int pause_end = starttime + RWD_TIME_PAUSE, bit_end;
                int bit = data & 1;
                data = data >> 1;

-               
-               if(bit) {
+
+               if(bit ^ legic_prng_get_bit()) {

                        bit_end = starttime + RWD_TIME_1;
                } else {
                        bit_end = starttime + RWD_TIME_0;
                }
                        bit_end = starttime + RWD_TIME_1;
                } else {
                        bit_end = starttime + RWD_TIME_0;
                }

-               
+

                /* RWD_TIME_PAUSE time off, then some time on, so that the complete bit time is
                 * RWD_TIME_x, where x is the bit to be transmitted */
                AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
                while(timer->TC_CV < pause_end) ;
                AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
                /* RWD_TIME_PAUSE time off, then some time on, so that the complete bit time is
                 * RWD_TIME_x, where x is the bit to be transmitted */
                AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
                while(timer->TC_CV < pause_end) ;
                AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;

+               legic_prng_forward(1); /* bit duration is longest. use this time to forward the lfsr */
+

                while(timer->TC_CV < bit_end) ;
        }
                while(timer->TC_CV < bit_end) ;
        }

-       
+

        {
                /* One final pause to mark the end of the frame */
                int pause_end = timer->TC_CV + RWD_TIME_PAUSE;
        {
                /* One final pause to mark the end of the frame */
                int pause_end = timer->TC_CV + RWD_TIME_PAUSE;


@@ -77,7 +88,7 @@ static void frame_send_rwd(uint16_t data, int bits)
                while(timer->TC_CV < pause_end) ;
                AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
        }
                while(timer->TC_CV < pause_end) ;
                AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
        }

-       
+

        /* Reset the timer, to measure time until the start of the tag frame */
        timer->TC_CCR = AT91C_TC_SWTRG;
        while(timer->TC_CV > 1) ; /* Wait till the clock has reset */
        /* Reset the timer, to measure time until the start of the tag frame */
        timer->TC_CCR = AT91C_TC_SWTRG;
        while(timer->TC_CV > 1) ; /* Wait till the clock has reset */


@@ -85,12 +96,12 @@ static void frame_send_rwd(uint16_t data, int bits)
 
 /* Receive a frame from the card in reader emulation mode, the FPGA and
  * timer must have been set up by LegicRfReader and frame_send_rwd.
 
 /* Receive a frame from the card in reader emulation mode, the FPGA and
  * timer must have been set up by LegicRfReader and frame_send_rwd.

- * 
+ *

  * The LEGIC RF protocol from card to reader does not include explicit
  * frame start/stop information or length information. The reader must
  * know beforehand how many bits it wants to receive. (Notably: a card
  * sending a stream of 0-bits is indistinguishable from no card present.)
  * The LEGIC RF protocol from card to reader does not include explicit
  * frame start/stop information or length information. The reader must
  * know beforehand how many bits it wants to receive. (Notably: a card
  * sending a stream of 0-bits is indistinguishable from no card present.)

- * 
+ *

  * Receive methodology: There is a fancy correlator in hi_read_rx_xcorr, but
  * I'm not smart enough to use it. Instead I have patched hi_read_tx to output
  * the ADC signal with hysteresis on SSP_DIN. Bit-bang that signal and look
  * Receive methodology: There is a fancy correlator in hi_read_rx_xcorr, but
  * I'm not smart enough to use it. Instead I have patched hi_read_tx to output
  * the ADC signal with hysteresis on SSP_DIN. Bit-bang that signal and look


@@ -99,30 +110,44 @@ static void frame_send_rwd(uint16_t data, int bits)
  * expected for a 212kHz subcarrier, this was a 1-bit. For timing we use the
  * timer that's still running from frame_send_rwd in order to get a synchronization
  * with the frame that we just sent.
  * expected for a 212kHz subcarrier, this was a 1-bit. For timing we use the
  * timer that's still running from frame_send_rwd in order to get a synchronization
  * with the frame that we just sent.

- * 
- * FIXME: Because we're relying on the hysteresis to just do the right thing 
+ *
+ * FIXME: Because we're relying on the hysteresis to just do the right thing

  * the range is severely reduced (and you'll probably also need a good antenna).
  * the range is severely reduced (and you'll probably also need a good antenna).

- * So this should be fixed some time in the future for a proper receiver. 
+ * So this should be fixed some time in the future for a proper receiver.

  */
  */

-static void frame_receive_rwd(struct legic_frame * const f, int bits)
+static void frame_receive_rwd(struct legic_frame * const f, int bits, int crypt)

 {
 {

-       uint16_t the_bit = 1;  /* Use a bitmask to save on shifts */
-       uint16_t data=0;
+       uint32_t the_bit = 1;  /* Use a bitmask to save on shifts */
+       uint32_t data=0;

        int i, old_level=0, edges=0;
        int next_bit_at = TAG_TIME_WAIT;
        int i, old_level=0, edges=0;
        int next_bit_at = TAG_TIME_WAIT;

-       
-       
+
+

        if(bits > 16)
                bits = 16;
 
        AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
        AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
 
        if(bits > 16)
                bits = 16;
 
        AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
        AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
 

+       /* we have some time now, precompute the cipher
+         * since we cannot compute it on the fly while reading */
+       legic_prng_forward(2);
+
+       if(crypt)
+       {
+               for(i=0; i<bits; i++) {
+                       data |= legic_prng_get_bit() << i;
+                       legic_prng_forward(1);
+               }
+       }
+

        while(timer->TC_CV < next_bit_at) ;
        while(timer->TC_CV < next_bit_at) ;

+

        next_bit_at += TAG_TIME_BIT;
        next_bit_at += TAG_TIME_BIT;

-       
+

        for(i=0; i<bits; i++) {
                edges = 0;
        for(i=0; i<bits; i++) {
                edges = 0;

+

                while(timer->TC_CV < next_bit_at) {
                        int level = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
                        if(level != old_level)
                while(timer->TC_CV < next_bit_at) {
                        int level = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
                        if(level != old_level)


@@ -130,18 +155,17 @@ static void frame_receive_rwd(struct legic_frame * const f, int bits)
                        old_level = level;
                }
                next_bit_at += TAG_TIME_BIT;
                        old_level = level;
                }
                next_bit_at += TAG_TIME_BIT;

-               
+

                if(edges > 20 && edges < 60) { /* expected are 42 edges */
                if(edges > 20 && edges < 60) { /* expected are 42 edges */

-                       data |= the_bit;
+                       data ^= the_bit;

                }
                }

-               
-               
+

                the_bit <<= 1;
        }
                the_bit <<= 1;
        }

-       
+

        f->data = data;
        f->bits = bits;
        f->data = data;
        f->bits = bits;

-       
+

        /* Reset the timer, to synchronize the next frame */
        timer->TC_CCR = AT91C_TC_SWTRG;
        while(timer->TC_CV > 1) ; /* Wait till the clock has reset */
        /* Reset the timer, to synchronize the next frame */
        timer->TC_CCR = AT91C_TC_SWTRG;
        while(timer->TC_CV > 1) ; /* Wait till the clock has reset */


@@ -153,100 +177,133 @@ static void frame_clean(struct legic_frame * const f)
        f->bits = 0;
 }
 
        f->bits = 0;
 }
 

-static uint16_t perform_setup_phase_rwd(void)
+static uint32_t perform_setup_phase_rwd(int iv)

 {
 {

-       
+

        /* Switch on carrier and let the tag charge for 1ms */
        AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
        SpinDelay(1);
        /* Switch on carrier and let the tag charge for 1ms */
        AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
        SpinDelay(1);

-       
-       frame_send_rwd(0x55, 7);
+
+       legic_prng_init(0); /* no keystream yet */
+       frame_send_rwd(iv, 7);
+        legic_prng_init(iv);
+

        frame_clean(&current_frame);
        frame_clean(&current_frame);

-       frame_receive_rwd(&current_frame, 6);
+       frame_receive_rwd(&current_frame, 6, 1);
+       legic_prng_forward(1); /* we wait anyways */

        while(timer->TC_CV < 387) ; /* ~ 258us */
        while(timer->TC_CV < 387) ; /* ~ 258us */

-       frame_send_rwd(0x019, 6);
-       
-       return current_frame.data ^ 0x26;
-}
+       frame_send_rwd(0x19, 6);

 
 

-static void switch_off_tag_rwd(void)
-{
-       /* Switch off carrier, make sure tag is reset */
-       AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
-       SpinDelay(10);
-       
-       WDT_HIT();
+       return current_frame.data;

 }
 
 }
 

-void LegicRfReader(void)
-{
+static void LegicCommonInit(void) {

        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
        FpgaSetupSsc();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX);
        SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
        FpgaSetupSsc();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX);

-       
+

        /* Bitbang the transmitter */
        AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
        AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
        AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
        /* Bitbang the transmitter */
        AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
        AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
        AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;

-       
+

        setup_timer();
        setup_timer();

-       
+
+       crc_init(&legic_crc, 4, 0x19 >> 1, 0x5, 0);
+}
+
+static void switch_off_tag_rwd(void)
+{
+       /* Switch off carrier, make sure tag is reset */
+       AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
+       SpinDelay(10);
+
+       WDT_HIT();
+}
+/* calculate crc for a legic command */
+static int LegicCRC(int byte_index, int value, int cmd_sz) {
+       crc_clear(&legic_crc);
+       crc_update(&legic_crc, 1, 1); /* CMD_READ */
+       crc_update(&legic_crc, byte_index, cmd_sz-1);
+       crc_update(&legic_crc, value, 8);
+       return crc_finish(&legic_crc);
+}
+
+int legic_read_byte(int byte_index, int cmd_sz) {
+       int byte;
+
+       legic_prng_forward(4); /* we wait anyways */
+       while(timer->TC_CV < 387) ; /* ~ 258us + 100us*delay */
+
+       frame_send_rwd(1 | (byte_index << 1), cmd_sz);
+       frame_clean(&current_frame);
+
+       frame_receive_rwd(&current_frame, 12, 1);
+
+       byte = current_frame.data & 0xff;
+       if( LegicCRC(byte_index, byte, cmd_sz) != (current_frame.data >> 8) ) {
+               Dbprintf("!!! crc mismatch: expected %x but got %x !!!", LegicCRC(byte_index, current_frame.data & 0xff, cmd_sz), current_frame.data >> 8);
+               return -1;
+       }
+
+       return byte;
+}
+
+/* legic_write_byte() is not included, however it's trivial to implement
+ * and here are some hints on what remains to be done:
+ *
+ *  * assemble a write_cmd_frame with crc and send it
+ *  * wait until the tag sends back an ACK ('1' bit unencrypted)
+ *  * forward the prng based on the timing
+ */
+
+
+void LegicRfReader(int offset, int bytes) {
+       int byte_index=0, cmd_sz=0, card_sz=0;
+
+       LegicCommonInit();
+

        memset(BigBuf, 0, 1024);
        memset(BigBuf, 0, 1024);

-       
-       int byte_index = 0, card_size = 0, command_size = 0;
-       uint16_t command_obfuscation = 0x57, response_obfuscation = 0;
-       uint16_t tag_type = perform_setup_phase_rwd();
-       switch_off_tag_rwd();
-       
-       int error = 0;
+
+       DbpString("setting up legic card");
+       uint32_t tag_type = perform_setup_phase_rwd(0x55);

        switch(tag_type) {
        switch(tag_type) {

-       case 0x1d:
-               DbpString("MIM 256 card found, reading card ...");
-               command_size = 9;
-               card_size = 256;
-               response_obfuscation = 0x52;
-               break;
-       case 0x3d:
-               DbpString("MIM 1024 card found, reading card ...");
-               command_size = 11;
-               card_size = 1024;
-               response_obfuscation = 0xd4;
-               break;
-       default:
-               DbpString("No or unknown card found, aborting");
-               error = 1;
-               break;
-       }
-       
-       LED_B_ON();
-       while(!BUTTON_PRESS() && (byte_index<card_size)) {
-               if(perform_setup_phase_rwd() != tag_type) {
-                       DbpString("Card removed, aborting");
-                       switch_off_tag_rwd();
-                       error=1;
+               case 0x1d:
+                       DbpString("MIM 256 card found, reading card ...");
+                       cmd_sz = 9;
+                       card_sz = 256;

                        break;
                        break;

-               }
-               
-               while(timer->TC_CV < 387) ; /* ~ 258us */
-               frame_send_rwd(command_obfuscation ^ (byte_index<<1), command_size);
-               frame_clean(&current_frame);
-               frame_receive_rwd(&current_frame, 8);
-               ((uint8_t*)BigBuf)[byte_index] = (current_frame.data ^ response_obfuscation) & 0xff;
-               
-               switch_off_tag_rwd();
-               
-               WDT_HIT();
-               byte_index++;
-               if(byte_index & 0x04) LED_C_ON(); else LED_C_OFF();
+               case 0x3d:
+                       DbpString("MIM 1024 card found, reading card ...");
+                       cmd_sz = 11;
+                       card_sz = 1024;
+                       break;
+               default:
+                       Dbprintf("Unknown card format: %x",tag_type);
+                       switch_off_tag_rwd();
+                       return;

        }
        }

-       LED_B_OFF();
-       LED_C_OFF();
-       
-       if(!error) {
-               if(card_size == 256) {
-                       DbpString("Card read, use hexsamples 256 to view results");
-               } else if(card_size == 1024) {
-                       DbpString("Card read, use hexsamples 1024 to view results");
+       if(bytes == -1) {
+               bytes = card_sz;
+       }
+        if(bytes+offset >= card_sz) {
+               bytes = card_sz-offset;
+        }
+
+       switch_off_tag_rwd(); //we lost to mutch time with dprintf
+       perform_setup_phase_rwd(0x55);
+
+       while(byte_index < bytes) {
+                int r = legic_read_byte(byte_index+offset, cmd_sz);
+                if(r == -1) {
+                       Dbprintf("aborting");
+                       switch_off_tag_rwd();
+                       return;

                }
                }

+               ((uint8_t*)BigBuf)[byte_index] = r;
+               byte_index++;

        }
        }

+       switch_off_tag_rwd();
+       Dbprintf("Card read, use 'hf legic decode' or 'data hexsamples %d' to view results", (bytes+7) & ~7);

 }
 }

+