iso14443b: trying to approach iClass
authorpwpiwi <pwpiwi@users.noreply.github.com>
Wed, 23 Oct 2019 07:09:13 +0000 (09:09 +0200)
committerpwpiwi <pwpiwi@users.noreply.github.com>
Wed, 23 Oct 2019 07:09:13 +0000 (09:09 +0200)
* decode and handle SOF only responses in Handle14443bSamplesDemod()
* allow 1 byte commands with 'hf 14b raw'

armsrc/iso14443b.c
client/cmdhf14b.c

index f276158fcf021760652312fede6b2e1daf611039..6434409d905312b945f85a139fc8a91d03cb7f18 100644 (file)
@@ -586,9 +586,10 @@ static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
                                        Demod.state = DEMOD_UNSYNCD;
                                } else {
                                        LED_C_ON(); // Got SOF
-                                       Demod.state = DEMOD_AWAITING_START_BIT;
                                        Demod.posCount = 0;
+                                       Demod.bitCount = 0;
                                        Demod.len = 0;
+                                       Demod.state = DEMOD_AWAITING_START_BIT;
 /* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented.
                                        Demod.metricN = 0;
                                        Demod.metric = 0;
@@ -605,13 +606,16 @@ static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
                case DEMOD_AWAITING_START_BIT:
                        Demod.posCount++;
                        MAKE_SOFT_DECISION();
-                       if(v > 0) {
-                               if(Demod.posCount > 3*2) {              // max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs
-                                       Demod.state = DEMOD_UNSYNCD;
+                       if (v > 0) {
+                               if (Demod.posCount > 3*2) {             // max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs
                                        LED_C_OFF();
+                                       if (Demod.bitCount == 0 && Demod.len == 0) { // received SOF only, this is valid for iClass/Picopass
+                                               return true;
+                                       } else {
+                                               Demod.state = DEMOD_UNSYNCD;
+                                       }
                                }
                        } else {                                                        // start bit detected
-                               Demod.bitCount = 0;
                                Demod.posCount = 1;                             // this was the first half
                                Demod.thisBit = v;
                                Demod.shiftReg = 0;
@@ -621,7 +625,7 @@ static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
 
                case DEMOD_RECEIVING_DATA:
                        MAKE_SOFT_DECISION();
-                       if(Demod.posCount == 0) {                       // first half of bit
+                       if (Demod.posCount == 0) {                      // first half of bit
                                Demod.thisBit = v;
                                Demod.posCount = 1;
                        } else {                                                        // second half of bit
@@ -637,22 +641,23 @@ static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
 */
 
                                Demod.shiftReg >>= 1;
-                               if(Demod.thisBit > 0) { // logic '1'
+                               if (Demod.thisBit > 0) {        // logic '1'
                                        Demod.shiftReg |= 0x200;
                                }
 
                                Demod.bitCount++;
-                               if(Demod.bitCount == 10) {
+                               if (Demod.bitCount == 10) {
                                        uint16_t s = Demod.shiftReg;
-                                       if((s & 0x200) && !(s & 0x001)) { // stop bit == '1', start bit == '0'
+                                       if ((s & 0x200) && !(s & 0x001)) { // stop bit == '1', start bit == '0'
                                                uint8_t b = (s >> 1);
                                                Demod.output[Demod.len] = b;
                                                Demod.len++;
+                                               Demod.bitCount = 0;
                                                Demod.state = DEMOD_AWAITING_START_BIT;
                                        } else {
                                                Demod.state = DEMOD_UNSYNCD;
                                                LED_C_OFF();
-                                               if(s == 0x000) {
+                                               if (s == 0x000) {
                                                        // This is EOF (start, stop and all data bits == '0'
                                                        return true;
                                                }
@@ -693,8 +698,8 @@ static void DemodInit(uint8_t *data)
  *  Demodulate the samples we received from the tag, also log to tracebuffer
  *  quiet: set to 'true' to disable debug output
  */
-static void GetSamplesFor14443bDemod(int timeout, bool quiet)
-{
+static int GetSamplesFor14443bDemod(int timeout, bool quiet) {
+       int ret = 0;
        int maxBehindBy = 0;
        bool gotFrame = false;
        int lastRxCounter, samples = 0;
@@ -750,12 +755,14 @@ static void GetSamplesFor14443bDemod(int timeout, bool quiet)
                }
                samples++;
 
-               if(Handle14443bSamplesDemod(ci, cq)) {
+               if (Handle14443bSamplesDemod(ci, cq)) {
+                       ret = Demod.len;
                        gotFrame = true;
                        break;
                }
 
                if(samples > timeout && Demod.state < DEMOD_PHASE_REF_TRAINING) {
+                       ret = -1;
                        LED_C_OFF();
                        break;
                }
@@ -764,10 +771,14 @@ static void GetSamplesFor14443bDemod(int timeout, bool quiet)
        FpgaDisableSscDma();
 
        if (!quiet) Dbprintf("max behindby = %d, samples = %d, gotFrame = %d, Demod.len = %d, Demod.sumI = %d, Demod.sumQ = %d", maxBehindBy, samples, gotFrame, Demod.len, Demod.sumI, Demod.sumQ);
-       //Tracing
-       if (Demod.len > 0) {
-               LogTrace(Demod.output, Demod.len, 0, 0, NULL, false);
+
+       if (ret < 0) {
+               return ret;
        }
+       //Tracing
+       LogTrace(Demod.output, Demod.len, 0, 0, NULL, false);
+
+       return ret;
 }
 
 
@@ -858,8 +869,7 @@ static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
 /* Sends an APDU to the tag
  * TODO: check CRC and preamble
  */
-int iso14443b_apdu(uint8_t const *message, size_t message_length, uint8_t *response)
-{
+int iso14443b_apdu(uint8_t const *message, size_t message_length, uint8_t *response) {
        LED_A_ON();
        uint8_t message_frame[message_length + 4];
        // PCB
@@ -874,21 +884,19 @@ int iso14443b_apdu(uint8_t const *message, size_t message_length, uint8_t *respo
        // send
        CodeAndTransmit14443bAsReader(message_frame, message_length + 4);
        // get response
-       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
+       int ret = GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
        FpgaDisableTracing();
-       if(Demod.len < 3)
-       {
+       if (ret < 3) {
                LED_A_OFF();
                return 0;
        }
        // TODO: Check CRC
        // copy response contents
-       if(response != NULL)
-       {
+       if (response != NULL) {
                memcpy(response, Demod.output, Demod.len);
        }
        LED_A_OFF();
-       return Demod.len;
+       return ret;
 }
 
 /* Perform the ISO 14443 B Card Selection procedure
@@ -907,10 +915,9 @@ int iso14443b_select_card()
 
        // first, wake up the tag
        CodeAndTransmit14443bAsReader(wupb, sizeof(wupb));
-       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
+       int ret = GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
        // ATQB too short?
-       if (Demod.len < 14)
-       {
+       if (ret < 14) {
                return 2;
        }
 
@@ -922,10 +929,9 @@ int iso14443b_select_card()
     attrib[7] = Demod.output[10] & 0x0F;
     ComputeCrc14443(CRC_14443_B, attrib, 9, attrib + 9, attrib + 10);
     CodeAndTransmit14443bAsReader(attrib, sizeof(attrib));
-    GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
+    ret = GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
     // Answer to ATTRIB too short?
-    if(Demod.len < 3)
-       {
+    if (ret < 3) {
                return 2;
        }
        // reset PCB block number
@@ -985,9 +991,9 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
        // First command: wake up the tag using the INITIATE command
        uint8_t cmd1[] = {0x06, 0x00, 0x97, 0x5b};
        CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
-       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
+       int ret = GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
 
-       if (Demod.len == 0) {
+       if (ret < 0) {
                FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
                DbpString("No response from tag");
                LEDsoff();
@@ -1003,7 +1009,7 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
        cmd1[1] = Demod.output[0];
        ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
        CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
-       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
+       ret = GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
        if (Demod.len != 3) {
                FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
                Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);
@@ -1031,8 +1037,8 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
        cmd1[0] = 0x0B;
        ComputeCrc14443(CRC_14443_B, cmd1, 1 , &cmd1[1], &cmd1[2]);
        CodeAndTransmit14443bAsReader(cmd1, 3); // Only first three bytes for this one
-       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
-       if (Demod.len != 10) {
+       ret = GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
+       if (ret != 10) {
                FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
                Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
                LEDsoff();
@@ -1062,8 +1068,8 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
                cmd1[1] = i;
                ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
                CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
-               GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
-               if (Demod.len != 6) { // Check if we got an answer from the tag
+               ret = GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
+               if (ret != 6) { // Check if we got an answer from the tag
                        FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
                        DbpString("Expected 6 bytes from tag, got less...");
                        LEDsoff();
@@ -1071,7 +1077,7 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
                }
                // The check the CRC of the answer (use cmd1 as temporary variable):
                ComputeCrc14443(CRC_14443_B, Demod.output, 4, &cmd1[2], &cmd1[3]);
-               if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {
+               if (cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {
                        Dbprintf("CRC Error reading block! Expected: %04x got: %04x",
                                        (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);
                        // Do not return;, let's go on... (we should retry, maybe ?)
@@ -1213,8 +1219,8 @@ void RAMFUNC SnoopIso14443b(void)
                        ReaderIsActive = (Uart.state > STATE_GOT_FALLING_EDGE_OF_SOF);
                }
 
-               if(!ReaderIsActive && triggered) {                                              // no need to try decoding tag data if the reader is sending or not yet triggered
-                       if(Handle14443bSamplesDemod(ci/2, cq/2)) {
+               if (!ReaderIsActive && triggered) {                                             // no need to try decoding tag data if the reader is sending or not yet triggered
+                       if (Handle14443bSamplesDemod(ci/2, cq/2) >= 0) {
                                //Use samples as a time measurement
                                LogTrace(Demod.output, Demod.len, samples, samples, NULL, false);
                                // And ready to receive another response.
@@ -1265,17 +1271,17 @@ void SendRawCommand14443B(uint32_t datalen, uint32_t recv, uint8_t powerfield, u
                
                CodeAndTransmit14443bAsReader(data, datalen);
 
-               if(recv) {
-                       GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, true);
+               if (recv) {
+                       int ret = GetSamplesFor14443bDemod(5*RECEIVE_SAMPLES_TIMEOUT, true);
                        FpgaDisableTracing();
                        uint16_t iLen = MIN(Demod.len, USB_CMD_DATA_SIZE);
-                       cmd_send(CMD_ACK, iLen, 0, 0, Demod.output, iLen);
+                       cmd_send(CMD_ACK, ret, 0, 0, Demod.output, iLen);
                }
 
                FpgaDisableTracing();
        }
 
-       if(!powerfield) {
+       if (!powerfield) {
                FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
                LED_D_OFF();
        }
index 8a83df8f76f98a3ee6776acaa68f27a8d0244061..4685f3f504fbdc193c753593022523bced4c9c33 100644 (file)
@@ -108,9 +108,21 @@ int HF14BCmdRaw(bool reply, bool *crc, bool power, uint8_t *data, uint8_t *datal
                if (verbose) PrintAndLog("timeout while waiting for reply.");
                return 0;
        }
-       *datalen = resp.arg[0];
-       if (verbose) PrintAndLog("received %u octets", *datalen);
-       if (*datalen < 2) return 0;
+
+       int ret = resp.arg[0];
+       if (verbose) {
+               if (ret < 0) {
+                       PrintAndLog("tag didn't respond");
+               } else if (ret == 0) {
+                       PrintAndLog("received SOF only (maybe iCLASS/Picopass)");
+               } else {
+                       PrintAndLog("received %u octets", ret);
+               }
+       }
+
+       *datalen = ret;
+       
+       if (ret < 2) return 0;
 
        memcpy(data, resp.d.asBytes, *datalen);
        if (verbose) PrintAndLog("%s", sprint_hex(data, *datalen));
@@ -139,7 +151,7 @@ static int CmdHF14BCmdRaw (const char *Cmd) {
        uint8_t datalen = 0;
        unsigned int temp;
        int i = 0;
-       if (strlen(Cmd) < 3) {
+       if (strlen(Cmd) < 2) {
                        PrintAndLog("Usage: hf 14b raw [-r] [-c] [-p] [-s || -ss] <0A 0B 0C ... hex>");
                        PrintAndLog("       -r    do not read response");
                        PrintAndLog("       -c    calculate and append CRC");
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