Changelog modified

[proxmark3-svn] / armsrc / iso14443a.c

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index 9fa9fe4ff61d8724036feeebeaa182a98b84a341..27574dad2601cceda2f59b785445a1915a958892 100644 (file)
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -2055,19 +2055,20 @@ void ReaderMifare(bool first_try)
        byte_t par_list[8] = {0x00};
        byte_t ks_list[8] = {0x00};
 
        byte_t par_list[8] = {0x00};
        byte_t ks_list[8] = {0x00};
 

+       #define PRNG_SEQUENCE_LENGTH  (1 << 16);

        static uint32_t sync_time;
        static uint32_t sync_time;

-       static uint32_t sync_cycles;
+       static int32_t sync_cycles;

        int catch_up_cycles = 0;
        int last_catch_up = 0;
        int catch_up_cycles = 0;
        int last_catch_up = 0;

+       uint16_t elapsed_prng_sequences;

        uint16_t consecutive_resyncs = 0;
        int isOK = 0;
 
        if (first_try) { 
                mf_nr_ar3 = 0;
                sync_time = GetCountSspClk() & 0xfffffff8;
        uint16_t consecutive_resyncs = 0;
        int isOK = 0;
 
        if (first_try) { 
                mf_nr_ar3 = 0;
                sync_time = GetCountSspClk() & 0xfffffff8;

-               sync_cycles = 65536;                                                                    // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
+               sync_cycles = PRNG_SEQUENCE_LENGTH;                                                     // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the tag nonces).

                nt_attacked = 0;
                nt_attacked = 0;

-               nt = 0;

                par[0] = 0;
        }
        else {
                par[0] = 0;
        }
        else {


@@ -2082,8 +2083,17 @@ void ReaderMifare(bool first_try)
        LED_C_OFF();
        
 
        LED_C_OFF();
        
 

-       #define DARKSIDE_MAX_TRIES      32              // number of tries to sync on PRNG cycle. Then give up.
-       uint16_t unsuccessfull_tries = 0;
+       #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
+       #define NUM_DEBUG_INFOS                 8               // per strategy
+       #define MAX_STRATEGY                    3
+       uint16_t unexpected_random = 0;
+       uint16_t sync_tries = 0;
+       int16_t debug_info_nr = -1;
+       uint16_t strategy = 0;
+       int32_t debug_info[MAX_STRATEGY][NUM_DEBUG_INFOS];
+       uint32_t select_time;
+       uint32_t halt_time;

        
        for(uint16_t i = 0; TRUE; i++) {
                
        
        for(uint16_t i = 0; TRUE; i++) {
                


@@ -2096,21 +2106,60 @@ void ReaderMifare(bool first_try)
                        break;
                }
                
                        break;
                }
                

+               if (strategy == 2) {
+                       // test with additional hlt command
+                       halt_time = 0;
+                       int len = mifare_sendcmd_short(NULL, false, 0x50, 0x00, receivedAnswer, receivedAnswerPar, &halt_time);
+                       if (len && MF_DBGLEVEL >= 3) {
+                               Dbprintf("Unexpected response of %d bytes to hlt command (additional debugging).", len);
+                       }
+               }
+
+               if (strategy == 3) {
+                       // test with FPGA power off/on
+                       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+                       SpinDelay(200);
+                       iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
+                       SpinDelay(100);
+               }
+               

                if(!iso14443a_select_card(uid, NULL, &cuid)) {
                        if (MF_DBGLEVEL >= 1)   Dbprintf("Mifare: Can't select card");
                        continue;
                }
                if(!iso14443a_select_card(uid, NULL, &cuid)) {
                        if (MF_DBGLEVEL >= 1)   Dbprintf("Mifare: Can't select card");
                        continue;
                }

+               select_time = GetCountSspClk();

 
 

-               sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
-               catch_up_cycles = 0;
+               elapsed_prng_sequences = 1;
+               if (debug_info_nr == -1) {
+                       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) {
-                       sync_time = (sync_time & 0xfffffff8) + sync_cycles;
-               }
+                       // 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);
+                       // Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked) 
+                       ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
+               } else {
+                       // collect some information on tag nonces for debugging:
+                       #define DEBUG_FIXED_SYNC_CYCLES PRNG_SEQUENCE_LENGTH
+                       if (strategy == 0) {
+                               // nonce distances at fixed time after card select:
+                               sync_time = select_time + DEBUG_FIXED_SYNC_CYCLES;
+                       } else if (strategy == 1) {
+                               // nonce distances at fixed time between authentications:
+                               sync_time = sync_time + DEBUG_FIXED_SYNC_CYCLES;
+                       } else if (strategy == 2) {
+                               // nonce distances at fixed time after halt:
+                               sync_time = halt_time + DEBUG_FIXED_SYNC_CYCLES;
+                       } else {
+                               // nonce_distances at fixed time after power on
+                               sync_time = DEBUG_FIXED_SYNC_CYCLES;
+                       }
+                       ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
+               }                       

 
                // Receive the (4 Byte) "random" nonce
                if (!ReaderReceive(receivedAnswer, receivedAnswerPar)) {
 
                // Receive the (4 Byte) "random" nonce
                if (!ReaderReceive(receivedAnswer, receivedAnswerPar)) {


@@ -2128,19 +2177,37 @@ void ReaderMifare(bool first_try)
                        int nt_distance = dist_nt(previous_nt, nt);
                        if (nt_distance == 0) {
                                nt_attacked = nt;
                        int nt_distance = dist_nt(previous_nt, nt);
                        if (nt_distance == 0) {
                                nt_attacked = nt;

-                       }
-                       else {
+                       } else {

                                if (nt_distance == -99999) { // invalid nonce received
                                if (nt_distance == -99999) { // invalid nonce received

-                                       unsuccessfull_tries++;
-                                       if (!nt_attacked && unsuccessfull_tries > DARKSIDE_MAX_TRIES) {
+                                       unexpected_random++;
+                                       if (unexpected_random > MAX_UNEXPECTED_RANDOM) {

                                                isOK = -3;              // Card has an unpredictable PRNG. Give up      
                                                break;
                                        } else {
                                                continue;               // continue trying...
                                        }
                                }
                                                isOK = -3;              // Card has an unpredictable PRNG. Give up      
                                                break;
                                        } else {
                                                continue;               // continue trying...
                                        }
                                }

-                               sync_cycles = (sync_cycles - nt_distance);
-                               if (MF_DBGLEVEL >= 3) Dbprintf("calibrating in cycle %d. nt_distance=%d, Sync_cycles: %d\n", i, nt_distance, sync_cycles);
+                               if (++sync_tries > MAX_SYNC_TRIES) {
+                                       if (strategy > MAX_STRATEGY || MF_DBGLEVEL < 3) {
+                                               isOK = -4;                      // Card's PRNG runs at an unexpected frequency or resets unexpectedly
+                                               break;
+                                       } else {                                // continue for a while, just to collect some debug info
+                                               debug_info[strategy][debug_info_nr] = nt_distance;
+                                               debug_info_nr++;
+                                               if (debug_info_nr == NUM_DEBUG_INFOS) {
+                                                       strategy++;
+                                                       debug_info_nr = 0;
+                                               }
+                                               continue;
+                                       }
+                               }
+                               sync_cycles = (sync_cycles - nt_distance/elapsed_prng_sequences);
+                               if (sync_cycles <= 0) {
+                                       sync_cycles += PRNG_SEQUENCE_LENGTH;
+                               }
+                               if (MF_DBGLEVEL >= 3) {
+                                       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;
                        }
                }
                                continue;
                        }
                }


@@ -2151,6 +2218,7 @@ void ReaderMifare(bool first_try)
                                catch_up_cycles = 0;
                                continue;
                        }
                                catch_up_cycles = 0;
                                continue;
                        }

+                       catch_up_cycles /= elapsed_prng_sequences;

                        if (catch_up_cycles == last_catch_up) {
                                consecutive_resyncs++;
                        }
                        if (catch_up_cycles == last_catch_up) {
                                consecutive_resyncs++;
                        }


@@ -2164,6 +2232,9 @@ void ReaderMifare(bool first_try)
                        else {  
                                sync_cycles = sync_cycles + catch_up_cycles;
                                if (MF_DBGLEVEL >= 3) 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);
                        else {  
                                sync_cycles = sync_cycles + catch_up_cycles;
                                if (MF_DBGLEVEL >= 3) 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;
                }
                        }
                        continue;
                }


@@ -2171,12 +2242,10 @@ void ReaderMifare(bool first_try)
                consecutive_resyncs = 0;
                
                // Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding
                consecutive_resyncs = 0;
                
                // Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding

-               if (ReaderReceive(receivedAnswer, receivedAnswerPar))
-               {
+               if (ReaderReceive(receivedAnswer, receivedAnswerPar)) {

                        catch_up_cycles = 8;    // the PRNG is delayed by 8 cycles due to the NAC (4Bits = 0x05 encrypted) transfer
        
                        catch_up_cycles = 8;    // the PRNG is delayed by 8 cycles due to the NAC (4Bits = 0x05 encrypted) transfer
        

-                       if (nt_diff == 0)
-                       {
+                       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_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
                        }
 


@@ -2211,6 +2280,16 @@ void ReaderMifare(bool first_try)
 
 
        mf_nr_ar[3] &= 0x1F;
 
 
        mf_nr_ar[3] &= 0x1F;

+
+       if (isOK == -4) {
+               if (MF_DBGLEVEL >= 3) {
+                       for (uint16_t i = 0; i <= MAX_STRATEGY; i++) {
+                               for(uint16_t j = 0; j < NUM_DEBUG_INFOS; j++) {
+                                       Dbprintf("collected debug info[%d][%d] = %d", i, j, debug_info[i][j]);
+                               }
+                       }
+               }
+       }

        
        byte_t buf[28];
        memcpy(buf + 0,  uid, 4);
        
        byte_t buf[28];
        memcpy(buf + 0,  uid, 4);