X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/7624e8b21bfb8468ae332a891a20df17f5077e58..d9cc4e1ae29f3fdad933e631076efe9ac0ac4e70:/armsrc/iso14443a.c diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c index 9fa9fe4f..27574dad 100644 --- 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}; + #define PRNG_SEQUENCE_LENGTH (1 << 16); 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; + uint16_t elapsed_prng_sequences; 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 = 0; par[0] = 0; } else { @@ -2082,8 +2083,17 @@ void ReaderMifare(bool first_try) 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++) { @@ -2096,21 +2106,60 @@ void ReaderMifare(bool first_try) 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; } + 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)) { @@ -2128,19 +2177,37 @@ void ReaderMifare(bool first_try) int nt_distance = dist_nt(previous_nt, nt); if (nt_distance == 0) { nt_attacked = nt; - } - else { + } else { 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... } } - 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; } } @@ -2151,6 +2218,7 @@ void ReaderMifare(bool first_try) catch_up_cycles = 0; continue; } + catch_up_cycles /= elapsed_prng_sequences; 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); + last_catch_up = 0; + catch_up_cycles = 0; + consecutive_resyncs = 0; } 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 - 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 - 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 } @@ -2211,6 +2280,16 @@ void ReaderMifare(bool first_try) 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);