(implementing suggestion #94)

[proxmark3-svn] / armsrc / iso14443a.c

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index cf64da2fbcdb3b8c3f6790cabac7429eef89d74f..2fd568b9e78b4cbd374ffe3836f2d06e775634d0 100644 (file)
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -1971,7 +1971,7 @@ int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
                nttmp1 = prng_successor(nttmp1, 1);
                if (nttmp1 == nt2) return i;
                nttmp2 = prng_successor(nttmp2, 1);
-                       if (nttmp2 == nt1) return -i;
+               if (nttmp2 == nt1) return -i;
                }
        
        return(-99999); // either nt1 or nt2 are invalid nonces
@@ -2040,18 +2040,21 @@ void ReaderMifare(bool first_try)
        LED_B_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;
+       
        for(uint16_t i = 0; TRUE; i++) {
                
+               LED_C_ON();
                WDT_HIT();
 
                // Test if the action was cancelled
                if(BUTTON_PRESS()) {
+                       isOK = -1;
                        break;
                }
                
-               LED_C_ON();
-
                if(!iso14443a_select_card(uid, NULL, &cuid)) {
                        if (MF_DBGLEVEL >= 1)   Dbprintf("Mifare: Can't select card");
                        continue;
@@ -2086,8 +2089,14 @@ void ReaderMifare(bool first_try)
                                nt_attacked = nt;
                        }
                        else {
-                               if (nt_distance == -99999) { // invalid nonce received, try again
-                                       continue;
+                               if (nt_distance == -99999) { // invalid nonce received
+                                       unsuccessfull_tries++;
+                                       if (!nt_attacked && unsuccessfull_tries > DARKSIDE_MAX_TRIES) {
+                                               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);
@@ -2149,6 +2158,10 @@ void ReaderMifare(bool first_try)
                        if (nt_diff == 0 && first_try)
                        {
                                par[0]++;
+                               if (par[0] == 0x00) {           // tried all 256 possible parities without success. Card doesn't send NACK.
+                                       isOK = -2;
+                                       break;
+                               }
                        } else {
                                par[0] = ((par[0] & 0x1F) + 1) | par_low;
                        }
@@ -2165,7 +2178,7 @@ void ReaderMifare(bool first_try)
        memcpy(buf + 16, ks_list, 8);
        memcpy(buf + 24, mf_nr_ar, 4);
                
-       cmd_send(CMD_ACK,isOK,0,0,buf,28);
+       cmd_send(CMD_ACK, isOK, 0, 0, buf, 28);
 
        // Thats it...
        FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);