CHG: "hf mf hardnested" - fixes and additions.

  - freeing candidate lists after generate_candidates calls.
  - longer timeout when waiting for responses (it takes a while to collect 58 nonces per call) From 3sec to 6sec
  - if best_first_byte[0] (best guess) has been the same for 3 nonces calls in a row, it enters the generate_candidates test.
  - when total_added_nonces increases but does not enter generate_candidates tests,  it now increases the threshold_index variable. Make the output look better

Known bugs still.
   - TestIfKeyExists sometimes crashes the client,  still after the null check.
   - proxmark3 device doesn't answer calls after entering brute_force call and fails finding a key,  where it should start collecting nonces again. This bug doesn't make sense.

diff --git a/client/cmdhfmfhard.c b/client/cmdhfmfhard.c
index ba524c5ca7aecdfbdbb82ee85810be453a496ac1..7197b1a0983b7f13f9d91e5c8f614edbbfd4a3a5 100644 (file)
--- a/client/cmdhfmfhard.c
+++ b/client/cmdhfmfhard.c
@@ -762,8 +762,20 @@ static void simulate_acquire_nonces()
                
 }
 
+static void    free_candidates_memory(statelist_t *sl)
+{
+       if (sl == NULL) {
+               return;
+       } else {
+               free_candidates_memory(sl->next);
+               free(sl);
+       }
+}
+
 static int acquire_nonces(uint8_t blockNo, uint8_t keyType, uint8_t *key, uint8_t trgBlockNo, uint8_t trgKeyType, bool nonce_file_write, bool slow)
 {
+       uint8_t three_in_row = 0;
+       uint8_t prev_best = 0;
        clock_t time1 = clock();
        bool initialize = true;
        bool finished = false;
@@ -776,15 +788,15 @@ static int acquire_nonces(uint8_t blockNo, uint8_t keyType, uint8_t *key, uint8_
        uint32_t idx = 1;
        FILE *fnonces = NULL;
        field_off = false;
-
        UsbCommand resp;
        UsbCommand c = {CMD_MIFARE_ACQUIRE_ENCRYPTED_NONCES, {0,0,0} };
        memcpy(c.d.asBytes, key, 6);    
        c.arg[0] = blockNo + (keyType * 0x100);
        c.arg[1] = trgBlockNo + (trgKeyType * 0x100);
-       
+               
        printf("Acquiring nonces...\n");
        do {
+       
                flags = 0;
                //flags |= initialize ? 0x0001 : 0;
                flags |= 0x0001;
@@ -797,7 +809,7 @@ static int acquire_nonces(uint8_t blockNo, uint8_t keyType, uint8_t *key, uint8_
                
                if (field_off) break;
 
-               if (!WaitForResponseTimeout(CMD_ACK, &resp, 3000)) {
+               if (!WaitForResponseTimeout(CMD_ACK, &resp, 6000)) {
                        if (fnonces) fclose(fnonces);
                        return 1;
                }
@@ -854,6 +866,12 @@ static int acquire_nonces(uint8_t blockNo, uint8_t keyType, uint8_t *key, uint8_
                        }
 
                        num_good_first_bytes = estimate_second_byte_sum();
+                       if ( prev_best == best_first_bytes[0] ){
+                               ++three_in_row;
+                       } else {
+                               three_in_row = 0;
+                       }
+                       prev_best = best_first_bytes[0];
 
                        if (total_num_nonces > next_fivehundred) {
                                next_fivehundred = (total_num_nonces/500+1) * 500;
@@ -862,23 +880,27 @@ static int acquire_nonces(uint8_t blockNo, uint8_t keyType, uint8_t *key, uint8_
                                        total_added_nonces,
                                        NONCES_THRESHOLD * idx,
                                        CONFIDENCE_THRESHOLD * 100.0,
-                                       num_good_first_bytes);
+                                       num_good_first_bytes
+                                       );
                        }
                        
                        if ( num_good_first_bytes > 0 ) {
                                //printf("GOOD BYTES: %s \n", sprint_hex(best_first_bytes, num_good_first_bytes) );
-                               if ( total_added_nonces >= (NONCES_THRESHOLD * idx)) {                                  
-
-                                       CmdFPGAOff("");
-                                               
+                               if ( total_added_nonces >= (NONCES_THRESHOLD * idx) || three_in_row >= 3) {
+                                       
                                        bool cracking = generate_candidates(first_byte_Sum, nonces[best_first_bytes[0]].Sum8_guess);
                                        if (cracking || known_target_key != -1) {
-                                               field_off = brute_force(); // switch off field with next SendCommand and then finish                                    
-                                               if (field_off) break;
+                                               
+                                               UsbCommand cOff = {CMD_FPGA_MAJOR_MODE_OFF, {0,0,0} };
+                                               SendCommand(&cOff);
+                                               field_off = brute_force();
                                        }
-                                       idx++;
+                                       free_candidates_memory(candidates);
                                }
                        }
+                       
+                       if ( total_added_nonces >= (NONCES_THRESHOLD * idx)) 
+                                       ++idx;
                }
        } while (!finished);
 
@@ -1246,6 +1268,10 @@ static bool TestIfKeyExists(uint64_t key)
        uint32_t state_even = pcs->even & 0x00ffffff;
        //printf("Tests: searching for key %llx after first byte 0x%02x (state_odd = 0x%06x, state_even = 0x%06x) ...\n", key, best_first_bytes[0], state_odd, state_even);
        printf("Validating keysearch space\n");
+       if ( candidates == NULL ) {
+                       printf("candidates list is NULL\n");
+                       return false;
+       }
        uint64_t count = 0;
        for (statelist_t *p = candidates; p != NULL; p = p->next) {
                bool found_odd = false;
@@ -1260,23 +1286,22 @@ static bool TestIfKeyExists(uint64_t key)
                        p_odd++;
                }
                while (*p_even != END_OF_LIST_MARKER) {
-                       if ((*p_even & 0x00ffffff) == state_even) {
+                       if ((*p_even & 0x00ffffff) == state_even)
                                found_even = true;
-                       }
+
                        p_even++;
                }
                count += (p_odd - p->states[ODD_STATE]) * (p_even - p->states[EVEN_STATE]);
                if (found_odd && found_even) {
                        if (known_target_key != -1) {
-                       PrintAndLog("Key Found after testing %llu (2^%1.1f) out of %lld (2^%1.1f) keys.", 
-                               count,
-                               log(count)/log(2), 
-                               maximum_states,
-                               log(maximum_states)/log(2)
-                               );
-                       if (write_stats) {
-                               fprintf(fstats, "1\n");
-                       }
+                               PrintAndLog("Key Found after testing %llu (2^%1.1f) out of %lld (2^%1.1f) keys.", 
+                                       count,
+                                       log(count)/log(2), 
+                                       maximum_states,
+                                       log(maximum_states)/log(2)
+                                       );
+                               if (write_stats)
+                                       fprintf(fstats, "1\n");                 
                        }
                        crypto1_destroy(pcs);
                        return true;
@@ -1284,13 +1309,11 @@ static bool TestIfKeyExists(uint64_t key)
        }
 
        if (known_target_key != -1) {
-       printf("Key NOT found!\n");
-       if (write_stats) {
-               fprintf(fstats, "0\n");
-       }
+               printf("Key NOT found!\n");
+               if (write_stats)
+                       fprintf(fstats, "0\n");
        }
        crypto1_destroy(pcs);
-
        return false;
 }
 
@@ -1375,16 +1398,6 @@ static bool generate_candidates(uint16_t sum_a0, uint16_t sum_a8)
        return false;
 }
 
-static void    free_candidates_memory(statelist_t *sl)
-{
-       if (sl == NULL) {
-               return;
-       } else {
-               free_candidates_memory(sl->next);
-               free(sl);
-       }
-}
-
 static void free_statelist_cache(void)
 {
        for (uint16_t i = 0; i < 17; i+=2) {