From f70008bd0cfe085280ad18781b4c6bd8eb6669f2 Mon Sep 17 00:00:00 2001 From: Antiklesys Date: Tue, 17 Sep 2024 15:08:15 +0800 Subject: [PATCH] Optimized legbrute Removed multithreading and bottlenecks in favor of sequentially generated keys. Multithreading can/should be reimplemented but optimized for keyspaces --- client/src/cmdhficlass.c | 113 ++++++++++++++------------------------- client/src/cmdhficlass.h | 1 + 2 files changed, 41 insertions(+), 73 deletions(-) diff --git a/client/src/cmdhficlass.c b/client/src/cmdhficlass.c index d6a7855b5..2fbef3a6d 100644 --- a/client/src/cmdhficlass.c +++ b/client/src/cmdhficlass.c @@ -3923,6 +3923,22 @@ void *generate_key_blocks(void *arg) { return NULL; } +void generate_key_block_inverted(const uint8_t *startingKey, uint32_t index, uint8_t *keyBlock) { + uint32_t carry = index; + memcpy(keyBlock, startingKey, PICOPASS_BLOCK_SIZE); + + for (int j = PICOPASS_BLOCK_SIZE - 1; j >= 0; j--) { + uint8_t increment_value = (carry & 0x1F) << 3; // Use the first 5 bits of carry and shift left by 3 to occupy the first 5 bits + keyBlock[j] = (keyBlock[j] & 0x07) | increment_value; // Preserve last 3 bits, modify the first 5 bits + + carry >>= 5; // Shift right by 5 bits for the next byte + if (carry == 0) { + // If no more carry, break early to avoid unnecessary loops + break; + } + } +} + static int CmdHFiClassLegRecLookUp(const char *Cmd) { //Standalone Command Start @@ -3939,6 +3955,7 @@ static int CmdHFiClassLegRecLookUp(const char *Cmd) { arg_str1(NULL, "macs1", "", "MACs captured from the reader"), arg_str1(NULL, "macs2", "", "MACs captured from the reader, different than the first set (with the same csn and epurse value)"), arg_str1(NULL, "pk", "", "Partial Key from legrec or starting key of keyblock from legbrute"), + arg_int0(NULL, "index", "", "Where to start from to retrieve the key, default 0"), arg_param_end }; CLIExecWithReturn(ctx, Cmd, argtable, false); @@ -4003,6 +4020,8 @@ static int CmdHFiClassLegRecLookUp(const char *Cmd) { } } + uint64_t index = arg_get_int_def(ctx, 6, 0); //has to be 64 as we're bruteforcing 40 bits + CLIParserFree(ctx); //Standalone Command End @@ -4029,80 +4048,31 @@ static int CmdHFiClassLegRecLookUp(const char *Cmd) { PrintAndLogEx(SUCCESS, "TAG MAC2: %s", sprint_hex(MAC_TAG2, sizeof(MAC_TAG2))); PrintAndLogEx(SUCCESS, "Starting Key: %s", sprint_hex(startingKey, 8)); - uint32_t keycount = 1000000; - uint32_t keys_per_thread = 250000; - uint32_t num_threads = keycount / keys_per_thread; - pthread_t threads[num_threads]; - ThreadData thread_data[num_threads]; - iclass_prekey_t *prekey = NULL; - iclass_prekey_t lookup; - iclass_prekey_t *item = NULL; - - memcpy(lookup.mac, MAC_TAG, 4); - - uint32_t block_index = 0; bool verified = false; + uint8_t div_key[PICOPASS_BLOCK_SIZE] = {0}; + uint8_t generated_mac[4] = {0, 0, 0, 0}; while (!verified) { - for (uint32_t t = 0; t < num_threads; t++) { - thread_data[t].start_index = block_index * keycount + t * keys_per_thread; - thread_data[t].keycount = keys_per_thread; - thread_data[t].startingKey = startingKey; - thread_data[t].keyBlock = calloc(keys_per_thread, PICOPASS_BLOCK_SIZE); - if (thread_data[t].keyBlock == NULL) { - PrintAndLogEx(ERR, "Memory allocation failed for keyBlock in thread %d.", t); - for (uint32_t i = 0; i < t; i++) { - free(thread_data[i].keyBlock); - } - return PM3_EINVARG; + //generate the key block + generate_key_block_inverted(startingKey, index, div_key); + + //generate the relevant macs + + doMAC(CCNR, div_key, generated_mac); + bool mac_match = true; + for (int i = 0; i < 4; i++) { + if (MAC_TAG[i] != generated_mac[i]) { + mac_match = false; } - - pthread_create(&threads[t], NULL, generate_key_blocks, (void *)&thread_data[t]); } - for (uint32_t t = 0; t < num_threads; t++) { - pthread_join(threads[t], NULL); - } - - if (prekey == NULL) { - prekey = calloc(keycount, sizeof(iclass_prekey_t)); - } else { - prekey = realloc(prekey, (block_index + 1) * keycount * sizeof(iclass_prekey_t)); - } - - if (prekey == NULL) { - PrintAndLogEx(ERR, "Memory allocation failed for prekey."); - for (uint32_t t = 0; t < num_threads; t++) { - free(thread_data[t].keyBlock); - } - return PM3_EINVARG; - } - - PrintAndLogEx(INFO, "Generating diversified keys...Index: " _YELLOW_("%d")" of ~1099511",block_index); - for (uint32_t t = 0; t < num_threads; t++) { - if(!t){ - PrintAndLogEx(SUCCESS, "KeyBlock Starting Key: %s", sprint_hex(thread_data[t].keyBlock[0], 8)); - } - GenerateMacKeyFrom(csn, CCNR, true, false, (uint8_t *)thread_data[t].keyBlock, keys_per_thread, prekey + (block_index * keycount) + (t * keys_per_thread)); - } - - PrintAndLogEx(INFO, "Sorting..."); - - // Sort mac list - qsort(prekey, (block_index + 1) * keycount, sizeof(iclass_prekey_t), cmp_uint32); - - PrintAndLogEx(SUCCESS, "Searching for " _YELLOW_("%s") " key...", "DEBIT"); - - // Binary search - item = (iclass_prekey_t *)bsearch(&lookup, prekey, (block_index + 1) * keycount, sizeof(iclass_prekey_t), cmp_uint32); - - if (item != NULL) { + if (mac_match) { //verify this against macs2 - PrintAndLogEx(WARNING, _YELLOW_("Found potentially valid RAW key ") _GREEN_("%s")_YELLOW_(" verifying it..."), sprint_hex(item->key, 8)); + PrintAndLogEx(WARNING, _YELLOW_("Found potentially valid RAW key ") _GREEN_("%s")_YELLOW_(" verifying it..."), sprint_hex(div_key, 8)); //generate the macs from the key and not the other way around, so we can quickly validate it uint8_t verification_mac[4] = {0, 0, 0, 0}; - doMAC(CCNR2, item->key, verification_mac); + doMAC(CCNR2, div_key, verification_mac); PrintAndLogEx(INFO, "Usr Provided Mac2: " _GREEN_("%s"), sprint_hex(MAC_TAG2, sizeof(MAC_TAG2))); PrintAndLogEx(INFO, "Verification Mac: " _GREEN_("%s"), sprint_hex(verification_mac, sizeof(verification_mac))); bool check_values = true; @@ -4112,23 +4082,20 @@ static int CmdHFiClassLegRecLookUp(const char *Cmd) { } } if(check_values){ - PrintAndLogEx(SUCCESS, _GREEN_("CONFIRMED VALID RAW key ") _RED_("%s"), sprint_hex(item->key, 8)); + PrintAndLogEx(SUCCESS, _GREEN_("CONFIRMED VALID RAW key ") _RED_("%s"), sprint_hex(div_key, 8)); verified = true; }else{ - PrintAndLogEx(INFO, _YELLOW_("Found potentially valid RAW key ") _GREEN_("%s")_YELLOW_(" verifying it..."), sprint_hex(item->key, 8)); - item = NULL; + PrintAndLogEx(INFO, _YELLOW_("Found potentially valid RAW key ") _GREEN_("%s")_YELLOW_(" verifying it..."), sprint_hex(div_key, 8)); } } - - for (uint32_t t = 0; t < num_threads; t++) { - free(thread_data[t].keyBlock); + if(index % 1000000 == 0){ + PrintAndLogEx(INFO, "Tested: " _YELLOW_("%d")" keys", index); + PrintAndLogEx(INFO, "Last Generated Key Value: " _YELLOW_("%s"), sprint_hex(div_key, 8)); } - - block_index++; + index++; } - free(prekey); PrintAndLogEx(NORMAL, ""); return PM3_SUCCESS; } diff --git a/client/src/cmdhficlass.h b/client/src/cmdhficlass.h index 2a3139059..1f1604ed0 100644 --- a/client/src/cmdhficlass.h +++ b/client/src/cmdhficlass.h @@ -43,4 +43,5 @@ uint32_t picopass_elite_rng(void); uint32_t picopass_elite_lcg(void); uint8_t picopass_elite_nextByte(void); void *generate_key_blocks(void *arg); +void generate_key_block_inverted(const uint8_t *startingKey, uint32_t index, uint8_t *keyBlock); #endif