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chg: 'hf mf nack' - cleaning up

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iceman1001 2017-12-05 18:14:19 +01:00
commit 8b3ff03599
1 changed files with 29 additions and 28 deletions
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55
armsrc/iso14443a.c
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@ -2288,6 +2288,11 @@ int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
return(-99999); // either nt1 or nt2 are invalid nonces
}
#define PRNG_SEQUENCE_LENGTH (1 << 16)
#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
//-----------------------------------------------------------------------------
// Recover several bits of the cypher stream. This implements (first stages of)
// the algorithm described in "The Dark Side of Security by Obscurity and
@ -2297,7 +2302,7 @@ int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
void ReaderMifare(bool first_try, uint8_t block, uint8_t keytype ) {
uint8_t mf_auth[] = { keytype, block, 0x00, 0x00 };
uint8_t mf_nr_ar[] = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
uint8_t mf_nr_ar[] = {0,0,0,0,0,0,0,0};
uint8_t uid[10] = {0,0,0,0,0,0,0,0,0,0};
uint8_t par_list[8] = {0,0,0,0,0,0,0,0};
uint8_t ks_list[8] = {0,0,0,0,0,0,0,0};
@ -2312,13 +2317,15 @@ void ReaderMifare(bool first_try, uint8_t block, uint8_t keytype ) {
int32_t catch_up_cycles = 0;
int32_t last_catch_up = 0;
int32_t isOK = 0;
int32_t nt_distance = 0;
uint16_t elapsed_prng_sequences = 1;
uint16_t consecutive_resyncs = 0;
uint16_t unexpected_random = 0;
uint16_t sync_tries = 0;
bool have_uid = false;
uint8_t cascade_levels = 0;
// static variables here, is re-used in the next call
static uint32_t nt_attacked = 0;
static uint32_t sync_time = 0;
@ -2326,24 +2333,12 @@ void ReaderMifare(bool first_try, uint8_t block, uint8_t keytype ) {
static uint8_t par_low = 0;
static uint8_t mf_nr_ar3 = 0;
#define PRNG_SEQUENCE_LENGTH (1 << 16)
#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
AppendCrc14443a(mf_auth, 2);
BigBuf_free(); BigBuf_Clear_ext(false);
clear_trace();
set_tracing(false);
iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
sync_time = GetCountSspClk() & 0xfffffff8;
sync_cycles = PRNG_SEQUENCE_LENGTH; // Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
nt_attacked = 0;
if (MF_DBGLEVEL >= 4) Dbprintf("Mifare::Sync %u", sync_time);
if (first_try) {
// create our reader nonce randomly
uint32_t nonce = prng_successor( GetCountSspClk() & 0xfffffff8 , 32);
num_to_bytes(nonce, 4, mf_nr_ar);
mf_nr_ar3 = 0;
par_low = 0;
} else {
@ -2354,8 +2349,16 @@ void ReaderMifare(bool first_try, uint8_t block, uint8_t keytype ) {
par[0] = par_low;
}
bool have_uid = false;
uint8_t cascade_levels = 0;
sync_cycles = PRNG_SEQUENCE_LENGTH; // Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
nt_attacked = 0;
BigBuf_free(); BigBuf_Clear_ext(false);
clear_trace();
set_tracing(false);
iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
sync_time = GetCountSspClk() & 0xfffffff8;
if (MF_DBGLEVEL >= 4) Dbprintf("Mifare::Sync %u", sync_time);
LED_C_ON();
uint16_t i;
@ -2391,6 +2394,7 @@ void ReaderMifare(bool first_try, uint8_t block, uint8_t keytype ) {
}
elapsed_prng_sequences = 1;
// Sending timeslot of ISO14443a frame
sync_time = (sync_time & 0xfffffff8 ) + sync_cycles + catch_up_cycles;
catch_up_cycles = 0;
@ -2418,7 +2422,7 @@ void ReaderMifare(bool first_try, uint8_t block, uint8_t keytype ) {
// iceman: has to be calibrated every time.
if (previous_nt && !nt_attacked) {
nt_distance = dist_nt(previous_nt, nt);
int nt_distance = dist_nt(previous_nt, nt);
// if no distance between, then we are in sync.
if (nt_distance == 0) {
@ -2430,7 +2434,7 @@ void ReaderMifare(bool first_try, uint8_t block, uint8_t keytype ) {
isOK = -3; // Card has an unpredictable PRNG. Give up
break;
} else {
if (sync_cycles <= 0) sync_cycles += PRNG_SEQUENCE_LENGTH;
// if (sync_cycles <= 0) sync_cycles += PRNG_SEQUENCE_LENGTH;
LED_B_OFF();
continue; // continue trying...
}
@ -2457,7 +2461,7 @@ void ReaderMifare(bool first_try, uint8_t block, uint8_t keytype ) {
if ( (nt != nt_attacked) && nt_attacked) { // we somehow lost sync. Try to catch up again...
catch_up_cycles = ABS(dist_nt(nt_attacked, nt));
catch_up_cycles = -dist_nt(nt_attacked, nt);
if (catch_up_cycles == 99999) { // invalid nonce received. Don't resync on that one.
catch_up_cycles = 0;
continue;
@ -2473,8 +2477,9 @@ void ReaderMifare(bool first_try, uint8_t block, uint8_t keytype ) {
}
if (consecutive_resyncs < 3) {
if (MF_DBGLEVEL >= 4)
if (MF_DBGLEVEL >= 4) {
Dbprintf("Lost sync in cycle %d. nt_distance=%d. Consecutive Resyncs = %d. Trying one time catch up...\n", i, catch_up_cycles, consecutive_resyncs);
}
} else {
sync_cycles += catch_up_cycles;
@ -2550,10 +2555,6 @@ void ReaderMifare(bool first_try, uint8_t block, uint8_t keytype ) {
*/
void DetectNACKbug() {
#define PRNG_SEQUENCE_LENGTH (1 << 16)
#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
uint8_t mf_auth[] = {0x60, 0x00, 0xF5, 0x7B};
uint8_t mf_nr_ar[] = {0,0,0,0,0,0,0,0};
uint8_t uid[10] = {0,0,0,0,0,0,0,0,0,0};