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flipperzero-firmware/lib/nfc/protocols/mifare_classic.c
Astra 55f8beef9f
[FL-2876] MFC Improvements Part 2/2 (#1868) 
* Remove keys incorrectly added by the key cache
* Improve responsiveness while checking for re-used keys and fix skipping keys when card is removed
* Actually check if the card is completely read
* Discard incorrect keys on a lower level
* nfc: clean up

Co-authored-by: gornekich <n.gorbadey@gmail.com>
2022-10-14 01:23:29 +09:00

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#include "mifare_classic.h"
#include "nfca.h"
#include "nfc_util.h"
#include <furi_hal_rtc.h>
// Algorithm from https://github.com/RfidResearchGroup/proxmark3.git
#define TAG "MfClassic"
#define MF_CLASSIC_AUTH_KEY_A_CMD (0x60U)
#define MF_CLASSIC_AUTH_KEY_B_CMD (0x61U)
#define MF_CLASSIC_READ_SECT_CMD (0x30)
typedef enum {
MfClassicActionDataRead,
MfClassicActionDataWrite,
MfClassicActionDataInc,
MfClassicActionDataDec,
MfClassicActionKeyARead,
MfClassicActionKeyAWrite,
MfClassicActionKeyBRead,
MfClassicActionKeyBWrite,
MfClassicActionACRead,
MfClassicActionACWrite,
} MfClassicAction;
const char* mf_classic_get_type_str(MfClassicType type) {
if(type == MfClassicType1k) {
return "MIFARE Classic 1K";
} else if(type == MfClassicType4k) {
return "MIFARE Classic 4K";
} else {
return "Unknown";
}
}
static uint8_t mf_classic_get_first_block_num_of_sector(uint8_t sector) {
furi_assert(sector < 40);
if(sector < 32) {
return sector * 4;
} else {
return 32 * 4 + (sector - 32) * 16;
}
}
uint8_t mf_classic_get_sector_trailer_block_num_by_sector(uint8_t sector) {
furi_assert(sector < 40);
if(sector < 32) {
return sector * 4 + 3;
} else {
return 32 * 4 + (sector - 32) * 16 + 15;
}
}
uint8_t mf_classic_get_sector_by_block(uint8_t block) {
if(block < 128) {
return (block | 0x03) / 4;
} else {
return 32 + ((block | 0xf) - 32 * 4) / 16;
}
}
static uint8_t mf_classic_get_blocks_num_in_sector(uint8_t sector) {
furi_assert(sector < 40);
return sector < 32 ? 4 : 16;
}
uint8_t mf_classic_get_sector_trailer_num_by_block(uint8_t block) {
if(block < 128) {
return block | 0x03;
} else {
return block | 0x0f;
}
}
bool mf_classic_is_sector_trailer(uint8_t block) {
return block == mf_classic_get_sector_trailer_num_by_block(block);
}
MfClassicSectorTrailer*
mf_classic_get_sector_trailer_by_sector(MfClassicData* data, uint8_t sector) {
furi_assert(data);
uint8_t sec_tr_block_num = mf_classic_get_sector_trailer_block_num_by_sector(sector);
return (MfClassicSectorTrailer*)data->block[sec_tr_block_num].value;
}
uint8_t mf_classic_get_total_sectors_num(MfClassicType type) {
if(type == MfClassicType1k) {
return MF_CLASSIC_1K_TOTAL_SECTORS_NUM;
} else if(type == MfClassicType4k) {
return MF_CLASSIC_4K_TOTAL_SECTORS_NUM;
} else {
return 0;
}
}
static uint16_t mf_classic_get_total_block_num(MfClassicType type) {
if(type == MfClassicType1k) {
return 64;
} else if(type == MfClassicType4k) {
return 256;
} else {
return 0;
}
}
bool mf_classic_is_block_read(MfClassicData* data, uint8_t block_num) {
furi_assert(data);
return (FURI_BIT(data->block_read_mask[block_num / 32], block_num % 32) == 1);
}
void mf_classic_set_block_read(MfClassicData* data, uint8_t block_num, MfClassicBlock* block_data) {
furi_assert(data);
if(mf_classic_is_sector_trailer(block_num)) {
memcpy(&data->block[block_num].value[6], &block_data->value[6], 4);
} else {
memcpy(data->block[block_num].value, block_data->value, MF_CLASSIC_BLOCK_SIZE);
}
FURI_BIT_SET(data->block_read_mask[block_num / 32], block_num % 32);
}
bool mf_classic_is_key_found(MfClassicData* data, uint8_t sector_num, MfClassicKey key_type) {
furi_assert(data);
bool key_found = false;
if(key_type == MfClassicKeyA) {
key_found = (FURI_BIT(data->key_a_mask, sector_num) == 1);
} else if(key_type == MfClassicKeyB) {
key_found = (FURI_BIT(data->key_b_mask, sector_num) == 1);
}
return key_found;
}
void mf_classic_set_key_found(
MfClassicData* data,
uint8_t sector_num,
MfClassicKey key_type,
uint64_t key) {
furi_assert(data);
uint8_t key_arr[6] = {};
MfClassicSectorTrailer* sec_trailer =
mf_classic_get_sector_trailer_by_sector(data, sector_num);
nfc_util_num2bytes(key, 6, key_arr);
if(key_type == MfClassicKeyA) {
memcpy(sec_trailer->key_a, key_arr, sizeof(sec_trailer->key_a));
FURI_BIT_SET(data->key_a_mask, sector_num);
} else if(key_type == MfClassicKeyB) {
memcpy(sec_trailer->key_b, key_arr, sizeof(sec_trailer->key_b));
FURI_BIT_SET(data->key_b_mask, sector_num);
}
}
void mf_classic_set_key_not_found(MfClassicData* data, uint8_t sector_num, MfClassicKey key_type) {
furi_assert(data);
if(key_type == MfClassicKeyA) {
FURI_BIT_CLEAR(data->key_a_mask, sector_num);
} else if(key_type == MfClassicKeyB) {
FURI_BIT_CLEAR(data->key_b_mask, sector_num);
}
}
bool mf_classic_is_sector_read(MfClassicData* data, uint8_t sector_num) {
furi_assert(data);
bool sector_read = false;
do {
if(!mf_classic_is_key_found(data, sector_num, MfClassicKeyA)) break;
if(!mf_classic_is_key_found(data, sector_num, MfClassicKeyB)) break;
uint8_t start_block = mf_classic_get_first_block_num_of_sector(sector_num);
uint8_t total_blocks = mf_classic_get_blocks_num_in_sector(sector_num);
uint8_t block_read = true;
for(size_t i = start_block; i < start_block + total_blocks; i++) {
block_read = mf_classic_is_block_read(data, i);
if(!block_read) break;
}
sector_read = block_read;
} while(false);
return sector_read;
}
void mf_classic_get_read_sectors_and_keys(
MfClassicData* data,
uint8_t* sectors_read,
uint8_t* keys_found) {
furi_assert(data);
*sectors_read = 0;
*keys_found = 0;
uint8_t sectors_total = mf_classic_get_total_sectors_num(data->type);
for(size_t i = 0; i < sectors_total; i++) {
if(mf_classic_is_key_found(data, i, MfClassicKeyA)) {
*keys_found += 1;
}
if(mf_classic_is_key_found(data, i, MfClassicKeyB)) {
*keys_found += 1;
}
uint8_t first_block = mf_classic_get_first_block_num_of_sector(i);
uint8_t total_blocks_in_sec = mf_classic_get_blocks_num_in_sector(i);
bool blocks_read = true;
for(size_t i = first_block; i < first_block + total_blocks_in_sec; i++) {
blocks_read = mf_classic_is_block_read(data, i);
if(!blocks_read) break;
}
if(blocks_read) {
*sectors_read += 1;
}
}
}
bool mf_classic_is_card_read(MfClassicData* data) {
furi_assert(data);
uint8_t sectors_total = mf_classic_get_total_sectors_num(data->type);
uint8_t sectors_read = 0;
uint8_t keys_found = 0;
mf_classic_get_read_sectors_and_keys(data, &sectors_read, &keys_found);
bool card_read = (sectors_read == sectors_total) && (keys_found == sectors_total * 2);
return card_read;
}
static bool mf_classic_is_allowed_access_sector_trailer(
MfClassicEmulator* emulator,
uint8_t block_num,
MfClassicKey key,
MfClassicAction action) {
uint8_t* sector_trailer = emulator->data.block[block_num].value;
uint8_t AC = ((sector_trailer[7] >> 5) & 0x04) | ((sector_trailer[8] >> 2) & 0x02) |
((sector_trailer[8] >> 7) & 0x01);
switch(action) {
case MfClassicActionKeyARead: {
return false;
}
case MfClassicActionKeyAWrite: {
return (
(key == MfClassicKeyA && (AC == 0x00 || AC == 0x01)) ||
(key == MfClassicKeyB && (AC == 0x04 || AC == 0x03)));
}
case MfClassicActionKeyBRead: {
return (key == MfClassicKeyA && (AC == 0x00 || AC == 0x02 || AC == 0x01));
}
case MfClassicActionKeyBWrite: {
return (
(key == MfClassicKeyA && (AC == 0x00 || AC == 0x01)) ||
(key == MfClassicKeyB && (AC == 0x04 || AC == 0x03)));
}
case MfClassicActionACRead: {
return (
(key == MfClassicKeyA) ||
(key == MfClassicKeyB && !(AC == 0x00 || AC == 0x02 || AC == 0x01)));
}
case MfClassicActionACWrite: {
return (
(key == MfClassicKeyA && (AC == 0x01)) ||
(key == MfClassicKeyB && (AC == 0x03 || AC == 0x05)));
}
default:
return false;
}
return true;
}
static bool mf_classic_is_allowed_access_data_block(
MfClassicEmulator* emulator,
uint8_t block_num,
MfClassicKey key,
MfClassicAction action) {
uint8_t* sector_trailer =
emulator->data.block[mf_classic_get_sector_trailer_num_by_block(block_num)].value;
uint8_t sector_block;
if(block_num <= 128) {
sector_block = block_num & 0x03;
} else {
sector_block = (block_num & 0x0f) / 5;
}
uint8_t AC;
switch(sector_block) {
case 0x00: {
AC = ((sector_trailer[7] >> 2) & 0x04) | ((sector_trailer[8] << 1) & 0x02) |
((sector_trailer[8] >> 4) & 0x01);
break;
}
case 0x01: {
AC = ((sector_trailer[7] >> 3) & 0x04) | ((sector_trailer[8] >> 0) & 0x02) |
((sector_trailer[8] >> 5) & 0x01);
break;
}
case 0x02: {
AC = ((sector_trailer[7] >> 4) & 0x04) | ((sector_trailer[8] >> 1) & 0x02) |
((sector_trailer[8] >> 6) & 0x01);
break;
}
default:
return false;
}
switch(action) {
case MfClassicActionDataRead: {
return (
(key == MfClassicKeyA && !(AC == 0x03 || AC == 0x05 || AC == 0x07)) ||
(key == MfClassicKeyB && !(AC == 0x07)));
}
case MfClassicActionDataWrite: {
return (
(key == MfClassicKeyA && (AC == 0x00)) ||
(key == MfClassicKeyB && (AC == 0x00 || AC == 0x04 || AC == 0x06 || AC == 0x03)));
}
case MfClassicActionDataInc: {
return (
(key == MfClassicKeyA && (AC == 0x00)) ||
(key == MfClassicKeyB && (AC == 0x00 || AC == 0x06)));
}
case MfClassicActionDataDec: {
return (
(key == MfClassicKeyA && (AC == 0x00 || AC == 0x06 || AC == 0x01)) ||
(key == MfClassicKeyB && (AC == 0x00 || AC == 0x06 || AC == 0x01)));
}
default:
return false;
}
return false;
}
static bool mf_classic_is_allowed_access(
MfClassicEmulator* emulator,
uint8_t block_num,
MfClassicKey key,
MfClassicAction action) {
if(mf_classic_is_sector_trailer(block_num)) {
return mf_classic_is_allowed_access_sector_trailer(emulator, block_num, key, action);
} else {
return mf_classic_is_allowed_access_data_block(emulator, block_num, key, action);
}
}
bool mf_classic_check_card_type(uint8_t ATQA0, uint8_t ATQA1, uint8_t SAK) {
UNUSED(ATQA1);
if((ATQA0 == 0x44 || ATQA0 == 0x04) && (SAK == 0x08 || SAK == 0x88 || SAK == 0x09)) {
return true;
} else if((ATQA0 == 0x01) && (ATQA1 == 0x0F) && (SAK == 0x01)) {
//skylanders support
return true;
} else if((ATQA0 == 0x42 || ATQA0 == 0x02) && (SAK == 0x18)) {
return true;
} else {
return false;
}
}
MfClassicType mf_classic_get_classic_type(int8_t ATQA0, uint8_t ATQA1, uint8_t SAK) {
UNUSED(ATQA1);
if((ATQA0 == 0x44 || ATQA0 == 0x04) && (SAK == 0x08 || SAK == 0x88 || SAK == 0x09)) {
return MfClassicType1k;
} else if((ATQA0 == 0x01) && (ATQA1 == 0x0F) && (SAK == 0x01)) {
//skylanders support
return MfClassicType1k;
} else if((ATQA0 == 0x42 || ATQA0 == 0x02) && (SAK == 0x18)) {
return MfClassicType4k;
}
return MfClassicType1k;
}
void mf_classic_reader_add_sector(
MfClassicReader* reader,
uint8_t sector,
uint64_t key_a,
uint64_t key_b) {
furi_assert(reader);
furi_assert(sector < MF_CLASSIC_SECTORS_MAX);
furi_assert((key_a != MF_CLASSIC_NO_KEY) || (key_b != MF_CLASSIC_NO_KEY));
if(reader->sectors_to_read < MF_CLASSIC_SECTORS_MAX) {
reader->sector_reader[reader->sectors_to_read].key_a = key_a;
reader->sector_reader[reader->sectors_to_read].key_b = key_b;
reader->sector_reader[reader->sectors_to_read].sector_num = sector;
reader->sectors_to_read++;
}
}
void mf_classic_auth_init_context(MfClassicAuthContext* auth_ctx, uint8_t sector) {
furi_assert(auth_ctx);
auth_ctx->sector = sector;
auth_ctx->key_a = MF_CLASSIC_NO_KEY;
auth_ctx->key_b = MF_CLASSIC_NO_KEY;
}
static bool mf_classic_auth(
FuriHalNfcTxRxContext* tx_rx,
uint32_t block,
uint64_t key,
MfClassicKey key_type,
Crypto1* crypto) {
bool auth_success = false;
uint32_t cuid = 0;
memset(tx_rx->tx_data, 0, sizeof(tx_rx->tx_data));
memset(tx_rx->tx_parity, 0, sizeof(tx_rx->tx_parity));
tx_rx->tx_rx_type = FuriHalNfcTxRxTypeDefault;
do {
if(!furi_hal_nfc_activate_nfca(200, &cuid)) break;
if(key_type == MfClassicKeyA) {
tx_rx->tx_data[0] = MF_CLASSIC_AUTH_KEY_A_CMD;
} else {
tx_rx->tx_data[0] = MF_CLASSIC_AUTH_KEY_B_CMD;
}
tx_rx->tx_data[1] = block;
tx_rx->tx_rx_type = FuriHalNfcTxRxTypeRxNoCrc;
tx_rx->tx_bits = 2 * 8;
if(!furi_hal_nfc_tx_rx(tx_rx, 6)) break;
uint32_t nt = (uint32_t)nfc_util_bytes2num(tx_rx->rx_data, 4);
crypto1_init(crypto, key);
crypto1_word(crypto, nt ^ cuid, 0);
uint8_t nr[4] = {};
nfc_util_num2bytes(prng_successor(DWT->CYCCNT, 32), 4, nr);
for(uint8_t i = 0; i < 4; i++) {
tx_rx->tx_data[i] = crypto1_byte(crypto, nr[i], 0) ^ nr[i];
tx_rx->tx_parity[0] |=
(((crypto1_filter(crypto->odd) ^ nfc_util_odd_parity8(nr[i])) & 0x01) << (7 - i));
}
nt = prng_successor(nt, 32);
for(uint8_t i = 4; i < 8; i++) {
nt = prng_successor(nt, 8);
tx_rx->tx_data[i] = crypto1_byte(crypto, 0x00, 0) ^ (nt & 0xff);
tx_rx->tx_parity[0] |=
(((crypto1_filter(crypto->odd) ^ nfc_util_odd_parity8(nt & 0xff)) & 0x01)
<< (7 - i));
}
tx_rx->tx_rx_type = FuriHalNfcTxRxTypeRaw;
tx_rx->tx_bits = 8 * 8;
if(!furi_hal_nfc_tx_rx(tx_rx, 6)) break;
if(tx_rx->rx_bits == 32) {
crypto1_word(crypto, 0, 0);
auth_success = true;
}
} while(false);
return auth_success;
}
bool mf_classic_authenticate(
FuriHalNfcTxRxContext* tx_rx,
uint8_t block_num,
uint64_t key,
MfClassicKey key_type) {
furi_assert(tx_rx);
Crypto1 crypto = {};
bool key_found = mf_classic_auth(tx_rx, block_num, key, key_type, &crypto);
furi_hal_nfc_sleep();
return key_found;
}
bool mf_classic_auth_attempt(
FuriHalNfcTxRxContext* tx_rx,
MfClassicAuthContext* auth_ctx,
uint64_t key) {
furi_assert(tx_rx);
furi_assert(auth_ctx);
bool found_key = false;
bool need_halt = (auth_ctx->key_a == MF_CLASSIC_NO_KEY) &&
(auth_ctx->key_b == MF_CLASSIC_NO_KEY);
Crypto1 crypto;
if(auth_ctx->key_a == MF_CLASSIC_NO_KEY) {
// Try AUTH with key A
if(mf_classic_auth(
tx_rx,
mf_classic_get_first_block_num_of_sector(auth_ctx->sector),
key,
MfClassicKeyA,
&crypto)) {
auth_ctx->key_a = key;
found_key = true;
}
}
if(need_halt) {
furi_hal_nfc_sleep();
}
if(auth_ctx->key_b == MF_CLASSIC_NO_KEY) {
// Try AUTH with key B
if(mf_classic_auth(
tx_rx,
mf_classic_get_first_block_num_of_sector(auth_ctx->sector),
key,
MfClassicKeyB,
&crypto)) {
auth_ctx->key_b = key;
found_key = true;
}
}
return found_key;
}
bool mf_classic_read_block(
FuriHalNfcTxRxContext* tx_rx,
Crypto1* crypto,
uint8_t block_num,
MfClassicBlock* block) {
furi_assert(tx_rx);
furi_assert(crypto);
furi_assert(block);
bool read_block_success = false;
uint8_t plain_cmd[4] = {MF_CLASSIC_READ_SECT_CMD, block_num, 0x00, 0x00};
nfca_append_crc16(plain_cmd, 2);
memset(tx_rx->tx_data, 0, sizeof(tx_rx->tx_data));
memset(tx_rx->tx_parity, 0, sizeof(tx_rx->tx_parity));
for(uint8_t i = 0; i < 4; i++) {
tx_rx->tx_data[i] = crypto1_byte(crypto, 0x00, 0) ^ plain_cmd[i];
tx_rx->tx_parity[0] |=
((crypto1_filter(crypto->odd) ^ nfc_util_odd_parity8(plain_cmd[i])) & 0x01) << (7 - i);
}
tx_rx->tx_bits = 4 * 9;
tx_rx->tx_rx_type = FuriHalNfcTxRxTypeRaw;
if(furi_hal_nfc_tx_rx(tx_rx, 50)) {
if(tx_rx->rx_bits == 8 * (MF_CLASSIC_BLOCK_SIZE + 2)) {
uint8_t block_received[MF_CLASSIC_BLOCK_SIZE + 2];
for(uint8_t i = 0; i < MF_CLASSIC_BLOCK_SIZE + 2; i++) {
block_received[i] = crypto1_byte(crypto, 0, 0) ^ tx_rx->rx_data[i];
}
uint16_t crc_calc = nfca_get_crc16(block_received, MF_CLASSIC_BLOCK_SIZE);
uint16_t crc_received = (block_received[MF_CLASSIC_BLOCK_SIZE + 1] << 8) |
block_received[MF_CLASSIC_BLOCK_SIZE];
if(crc_received != crc_calc) {
FURI_LOG_E(
TAG,
"Incorrect CRC while reading block %d. Expected %04X, Received %04X",
block_num,
crc_received,
crc_calc);
} else {
memcpy(block->value, block_received, MF_CLASSIC_BLOCK_SIZE);
read_block_success = true;
}
}
}
return read_block_success;
}
void mf_classic_read_sector(FuriHalNfcTxRxContext* tx_rx, MfClassicData* data, uint8_t sec_num) {
furi_assert(tx_rx);
furi_assert(data);
furi_hal_nfc_sleep();
bool key_a_found = mf_classic_is_key_found(data, sec_num, MfClassicKeyA);
bool key_b_found = mf_classic_is_key_found(data, sec_num, MfClassicKeyB);
uint8_t start_block = mf_classic_get_first_block_num_of_sector(sec_num);
uint8_t total_blocks = mf_classic_get_blocks_num_in_sector(sec_num);
MfClassicBlock block_tmp = {};
uint64_t key = 0;
MfClassicSectorTrailer* sec_tr = mf_classic_get_sector_trailer_by_sector(data, sec_num);
Crypto1 crypto = {};
uint8_t blocks_read = 0;
do {
if(!key_a_found) break;
FURI_LOG_D(TAG, "Try to read blocks with key A");
key = nfc_util_bytes2num(sec_tr->key_a, sizeof(sec_tr->key_a));
if(!mf_classic_auth(tx_rx, start_block, key, MfClassicKeyA, &crypto)) break;
for(size_t i = start_block; i < start_block + total_blocks; i++) {
if(!mf_classic_is_block_read(data, i)) {
if(mf_classic_read_block(tx_rx, &crypto, i, &block_tmp)) {
mf_classic_set_block_read(data, i, &block_tmp);
blocks_read++;
}
} else {
blocks_read++;
}
}
FURI_LOG_D(TAG, "Read %d blocks out of %d", blocks_read, total_blocks);
} while(false);
do {
if(blocks_read == total_blocks) break;
if(!key_b_found) break;
FURI_LOG_D(TAG, "Try to read blocks with key B");
key = nfc_util_bytes2num(sec_tr->key_b, sizeof(sec_tr->key_b));
furi_hal_nfc_sleep();
if(!mf_classic_auth(tx_rx, start_block, key, MfClassicKeyB, &crypto)) break;
for(size_t i = start_block; i < start_block + total_blocks; i++) {
if(!mf_classic_is_block_read(data, i)) {
if(mf_classic_read_block(tx_rx, &crypto, i, &block_tmp)) {
mf_classic_set_block_read(data, i, &block_tmp);
blocks_read++;
}
} else {
blocks_read++;
}
}
FURI_LOG_D(TAG, "Read %d blocks out of %d", blocks_read, total_blocks);
} while(false);
}
static bool mf_classic_read_sector_with_reader(
FuriHalNfcTxRxContext* tx_rx,
Crypto1* crypto,
MfClassicSectorReader* sector_reader,
MfClassicSector* sector) {
furi_assert(tx_rx);
furi_assert(sector_reader);
furi_assert(sector);
uint64_t key;
MfClassicKey key_type;
uint8_t first_block;
bool sector_read = false;
furi_hal_nfc_sleep();
do {
// Activate card
first_block = mf_classic_get_first_block_num_of_sector(sector_reader->sector_num);
if(sector_reader->key_a != MF_CLASSIC_NO_KEY) {
key = sector_reader->key_a;
key_type = MfClassicKeyA;
} else if(sector_reader->key_b != MF_CLASSIC_NO_KEY) {
key = sector_reader->key_b;
key_type = MfClassicKeyB;
} else {
break;
}
// Auth to first block in sector
if(!mf_classic_auth(tx_rx, first_block, key, key_type, crypto)) {
// Set key to MF_CLASSIC_NO_KEY to prevent further attempts
if(key_type == MfClassicKeyA) {
sector_reader->key_a = MF_CLASSIC_NO_KEY;
} else {
sector_reader->key_b = MF_CLASSIC_NO_KEY;
}
break;
}
sector->total_blocks = mf_classic_get_blocks_num_in_sector(sector_reader->sector_num);
// Read blocks
for(uint8_t i = 0; i < sector->total_blocks; i++) {
mf_classic_read_block(tx_rx, crypto, first_block + i, &sector->block[i]);
}
// Save sector keys in last block
if(sector_reader->key_a != MF_CLASSIC_NO_KEY) {
nfc_util_num2bytes(
sector_reader->key_a, 6, &sector->block[sector->total_blocks - 1].value[0]);
}
if(sector_reader->key_b != MF_CLASSIC_NO_KEY) {
nfc_util_num2bytes(
sector_reader->key_b, 6, &sector->block[sector->total_blocks - 1].value[10]);
}
sector_read = true;
} while(false);
return sector_read;
}
uint8_t mf_classic_read_card(
FuriHalNfcTxRxContext* tx_rx,
MfClassicReader* reader,
MfClassicData* data) {
furi_assert(tx_rx);
furi_assert(reader);
furi_assert(data);
uint8_t sectors_read = 0;
data->type = reader->type;
data->key_a_mask = 0;
data->key_b_mask = 0;
MfClassicSector temp_sector = {};
for(uint8_t i = 0; i < reader->sectors_to_read; i++) {
if(mf_classic_read_sector_with_reader(
tx_rx, &reader->crypto, &reader->sector_reader[i], &temp_sector)) {
uint8_t first_block =
mf_classic_get_first_block_num_of_sector(reader->sector_reader[i].sector_num);
for(uint8_t j = 0; j < temp_sector.total_blocks; j++) {
mf_classic_set_block_read(data, first_block + j, &temp_sector.block[j]);
}
if(reader->sector_reader[i].key_a != MF_CLASSIC_NO_KEY) {
mf_classic_set_key_found(
data,
reader->sector_reader[i].sector_num,
MfClassicKeyA,
reader->sector_reader[i].key_a);
}
if(reader->sector_reader[i].key_b != MF_CLASSIC_NO_KEY) {
mf_classic_set_key_found(
data,
reader->sector_reader[i].sector_num,
MfClassicKeyB,
reader->sector_reader[i].key_b);
}
sectors_read++;
}
}
return sectors_read;
}
uint8_t mf_classic_update_card(FuriHalNfcTxRxContext* tx_rx, MfClassicData* data) {
furi_assert(tx_rx);
furi_assert(data);
uint8_t sectors_read = 0;
Crypto1 crypto = {};
uint8_t total_sectors = mf_classic_get_total_sectors_num(data->type);
uint64_t key_a = 0;
uint64_t key_b = 0;
MfClassicSectorReader sec_reader = {};
MfClassicSector temp_sector = {};
for(size_t i = 0; i < total_sectors; i++) {
MfClassicSectorTrailer* sec_tr = mf_classic_get_sector_trailer_by_sector(data, i);
// Load key A
if(mf_classic_is_key_found(data, i, MfClassicKeyA)) {
sec_reader.key_a = nfc_util_bytes2num(sec_tr->key_a, 6);
} else {
sec_reader.key_a = MF_CLASSIC_NO_KEY;
}
// Load key B
if(mf_classic_is_key_found(data, i, MfClassicKeyB)) {
sec_reader.key_b = nfc_util_bytes2num(sec_tr->key_b, 6);
} else {
sec_reader.key_b = MF_CLASSIC_NO_KEY;
}
if((key_a != MF_CLASSIC_NO_KEY) || (key_b != MF_CLASSIC_NO_KEY)) {
sec_reader.sector_num = i;
if(mf_classic_read_sector_with_reader(tx_rx, &crypto, &sec_reader, &temp_sector)) {
uint8_t first_block = mf_classic_get_first_block_num_of_sector(i);
for(uint8_t j = 0; j < temp_sector.total_blocks; j++) {
mf_classic_set_block_read(data, first_block + j, &temp_sector.block[j]);
}
sectors_read++;
} else {
// Invalid key, set it to not found
if(key_a != MF_CLASSIC_NO_KEY) {
mf_classic_set_key_not_found(data, i, MfClassicKeyA);
} else {
mf_classic_set_key_not_found(data, i, MfClassicKeyB);
}
}
}
}
return sectors_read;
}
void mf_crypto1_decrypt(
Crypto1* crypto,
uint8_t* encrypted_data,
uint16_t encrypted_data_bits,
uint8_t* decrypted_data) {
if(encrypted_data_bits < 8) {
uint8_t decrypted_byte = 0;
decrypted_byte |= (crypto1_bit(crypto, 0, 0) ^ FURI_BIT(encrypted_data[0], 0)) << 0;
decrypted_byte |= (crypto1_bit(crypto, 0, 0) ^ FURI_BIT(encrypted_data[0], 1)) << 1;
decrypted_byte |= (crypto1_bit(crypto, 0, 0) ^ FURI_BIT(encrypted_data[0], 2)) << 2;
decrypted_byte |= (crypto1_bit(crypto, 0, 0) ^ FURI_BIT(encrypted_data[0], 3)) << 3;
decrypted_data[0] = decrypted_byte;
} else {
for(size_t i = 0; i < encrypted_data_bits / 8; i++) {
decrypted_data[i] = crypto1_byte(crypto, 0, 0) ^ encrypted_data[i];
}
}
}
void mf_crypto1_encrypt(
Crypto1* crypto,
uint8_t* keystream,
uint8_t* plain_data,
uint16_t plain_data_bits,
uint8_t* encrypted_data,
uint8_t* encrypted_parity) {
if(plain_data_bits < 8) {
encrypted_data[0] = 0;
for(size_t i = 0; i < plain_data_bits; i++) {
encrypted_data[0] |= (crypto1_bit(crypto, 0, 0) ^ FURI_BIT(plain_data[0], i)) << i;
}
} else {
memset(encrypted_parity, 0, plain_data_bits / 8 + 1);
for(uint8_t i = 0; i < plain_data_bits / 8; i++) {
encrypted_data[i] = crypto1_byte(crypto, keystream ? keystream[i] : 0, 0) ^
plain_data[i];
encrypted_parity[i / 8] |=
(((crypto1_filter(crypto->odd) ^ nfc_util_odd_parity8(plain_data[i])) & 0x01)
<< (7 - (i & 0x0007)));
}
}
}
bool mf_classic_emulator(MfClassicEmulator* emulator, FuriHalNfcTxRxContext* tx_rx) {
furi_assert(emulator);
furi_assert(tx_rx);
bool command_processed = false;
bool is_encrypted = false;
uint8_t plain_data[MF_CLASSIC_MAX_DATA_SIZE];
MfClassicKey access_key = MfClassicKeyA;
// Read command
while(!command_processed) {
if(!is_encrypted) {
crypto1_reset(&emulator->crypto);
memcpy(plain_data, tx_rx->rx_data, tx_rx->rx_bits / 8);
} else {
if(!furi_hal_nfc_tx_rx(tx_rx, 300)) {
FURI_LOG_D(
TAG,
"Error in tx rx. Tx :%d bits, Rx: %d bits",
tx_rx->tx_bits,
tx_rx->rx_bits);
break;
}
mf_crypto1_decrypt(&emulator->crypto, tx_rx->rx_data, tx_rx->rx_bits, plain_data);
}
if(plain_data[0] == 0x50 && plain_data[1] == 0x00) {
FURI_LOG_T(TAG, "Halt received");
furi_hal_nfc_listen_sleep();
command_processed = true;
break;
} else if(plain_data[0] == 0x60 || plain_data[0] == 0x61) {
uint8_t block = plain_data[1];
uint64_t key = 0;
uint8_t sector_trailer_block = mf_classic_get_sector_trailer_num_by_block(block);
MfClassicSectorTrailer* sector_trailer =
(MfClassicSectorTrailer*)emulator->data.block[sector_trailer_block].value;
if(plain_data[0] == 0x60) {
key = nfc_util_bytes2num(sector_trailer->key_a, 6);
access_key = MfClassicKeyA;
} else {
key = nfc_util_bytes2num(sector_trailer->key_b, 6);
access_key = MfClassicKeyB;
}
uint32_t nonce = prng_successor(DWT->CYCCNT, 32) ^ 0xAA;
uint8_t nt[4];
uint8_t nt_keystream[4];
nfc_util_num2bytes(nonce, 4, nt);
nfc_util_num2bytes(nonce ^ emulator->cuid, 4, nt_keystream);
crypto1_init(&emulator->crypto, key);
if(!is_encrypted) {
crypto1_word(&emulator->crypto, emulator->cuid ^ nonce, 0);
memcpy(tx_rx->tx_data, nt, sizeof(nt));
tx_rx->tx_parity[0] = 0;
for(size_t i = 0; i < sizeof(nt); i++) {
tx_rx->tx_parity[0] |= nfc_util_odd_parity8(nt[i]) << (7 - i);
}
tx_rx->tx_bits = sizeof(nt) * 8;
tx_rx->tx_rx_type = FuriHalNfcTxRxTransparent;
} else {
mf_crypto1_encrypt(
&emulator->crypto,
nt_keystream,
nt,
sizeof(nt) * 8,
tx_rx->tx_data,
tx_rx->tx_parity);
tx_rx->tx_bits = sizeof(nt) * 8;
tx_rx->tx_rx_type = FuriHalNfcTxRxTransparent;
}
if(!furi_hal_nfc_tx_rx(tx_rx, 500)) {
FURI_LOG_E(TAG, "Error in NT exchange");
command_processed = true;
break;
}
if(tx_rx->rx_bits != 64) {
FURI_LOG_W(TAG, "Incorrect nr + ar");
command_processed = true;
break;
}
uint32_t nr = nfc_util_bytes2num(tx_rx->rx_data, 4);
uint32_t ar = nfc_util_bytes2num(&tx_rx->rx_data[4], 4);
FURI_LOG_D(
TAG,
"%08lx key%c block %d nt/nr/ar: %08lx %08lx %08lx",
emulator->cuid,
access_key == MfClassicKeyA ? 'A' : 'B',
sector_trailer_block,
nonce,
nr,
ar);
crypto1_word(&emulator->crypto, nr, 1);
uint32_t cardRr = ar ^ crypto1_word(&emulator->crypto, 0, 0);
if(cardRr != prng_successor(nonce, 64)) {
FURI_LOG_T(TAG, "Wrong AUTH! %08lX != %08lX", cardRr, prng_successor(nonce, 64));
// Don't send NACK, as the tag doesn't send it
command_processed = true;
break;
}
uint32_t ans = prng_successor(nonce, 96);
uint8_t responce[4] = {};
nfc_util_num2bytes(ans, 4, responce);
mf_crypto1_encrypt(
&emulator->crypto,
NULL,
responce,
sizeof(responce) * 8,
tx_rx->tx_data,
tx_rx->tx_parity);
tx_rx->tx_bits = sizeof(responce) * 8;
tx_rx->tx_rx_type = FuriHalNfcTxRxTransparent;
is_encrypted = true;
} else if(is_encrypted && plain_data[0] == 0x30) {
uint8_t block = plain_data[1];
uint8_t block_data[18] = {};
memcpy(block_data, emulator->data.block[block].value, MF_CLASSIC_BLOCK_SIZE);
if(mf_classic_is_sector_trailer(block)) {
if(!mf_classic_is_allowed_access(
emulator, block, access_key, MfClassicActionKeyARead)) {
memset(block_data, 0, 6);
}
if(!mf_classic_is_allowed_access(
emulator, block, access_key, MfClassicActionKeyBRead)) {
memset(&block_data[10], 0, 6);
}
if(!mf_classic_is_allowed_access(
emulator, block, access_key, MfClassicActionACRead)) {
memset(&block_data[6], 0, 4);
}
} else {
if(!mf_classic_is_allowed_access(
emulator, block, access_key, MfClassicActionDataRead)) {
// Send NACK
uint8_t nack = 0x04;
if(is_encrypted) {
mf_crypto1_encrypt(
&emulator->crypto, NULL, &nack, 4, tx_rx->tx_data, tx_rx->tx_parity);
} else {
tx_rx->tx_data[0] = nack;
}
tx_rx->tx_rx_type = FuriHalNfcTxRxTransparent;
tx_rx->tx_bits = 4;
furi_hal_nfc_tx_rx(tx_rx, 300);
break;
}
}
nfca_append_crc16(block_data, 16);
mf_crypto1_encrypt(
&emulator->crypto,
NULL,
block_data,
sizeof(block_data) * 8,
tx_rx->tx_data,
tx_rx->tx_parity);
tx_rx->tx_bits = 18 * 8;
tx_rx->tx_rx_type = FuriHalNfcTxRxTransparent;
} else if(is_encrypted && plain_data[0] == 0xA0) {
uint8_t block = plain_data[1];
if(block > mf_classic_get_total_block_num(emulator->data.type)) {
break;
}
// Send ACK
uint8_t ack = 0x0A;
mf_crypto1_encrypt(&emulator->crypto, NULL, &ack, 4, tx_rx->tx_data, tx_rx->tx_parity);
tx_rx->tx_rx_type = FuriHalNfcTxRxTransparent;
tx_rx->tx_bits = 4;
if(!furi_hal_nfc_tx_rx(tx_rx, 300)) break;
if(tx_rx->rx_bits != 18 * 8) break;
mf_crypto1_decrypt(&emulator->crypto, tx_rx->rx_data, tx_rx->rx_bits, plain_data);
uint8_t block_data[16] = {};
memcpy(block_data, emulator->data.block[block].value, MF_CLASSIC_BLOCK_SIZE);
if(mf_classic_is_sector_trailer(block)) {
if(mf_classic_is_allowed_access(
emulator, block, access_key, MfClassicActionKeyAWrite)) {
memcpy(block_data, plain_data, 6);
}
if(mf_classic_is_allowed_access(
emulator, block, access_key, MfClassicActionKeyBWrite)) {
memcpy(&block_data[10], &plain_data[10], 6);
}
if(mf_classic_is_allowed_access(
emulator, block, access_key, MfClassicActionACWrite)) {
memcpy(&block_data[6], &plain_data[6], 4);
}
} else {
if(mf_classic_is_allowed_access(
emulator, block, access_key, MfClassicActionDataWrite)) {
memcpy(block_data, plain_data, MF_CLASSIC_BLOCK_SIZE);
}
}
if(memcmp(block_data, emulator->data.block[block].value, MF_CLASSIC_BLOCK_SIZE)) {
memcpy(emulator->data.block[block].value, block_data, MF_CLASSIC_BLOCK_SIZE);
emulator->data_changed = true;
}
// Send ACK
ack = 0x0A;
mf_crypto1_encrypt(&emulator->crypto, NULL, &ack, 4, tx_rx->tx_data, tx_rx->tx_parity);
tx_rx->tx_rx_type = FuriHalNfcTxRxTransparent;
tx_rx->tx_bits = 4;
} else {
// Unknown command
break;
}
}
if(!command_processed) {
// Send NACK
uint8_t nack = 0x04;
if(is_encrypted) {
mf_crypto1_encrypt(
&emulator->crypto, NULL, &nack, 4, tx_rx->tx_data, tx_rx->tx_parity);
} else {
tx_rx->tx_data[0] = nack;
}
tx_rx->tx_rx_type = FuriHalNfcTxRxTransparent;
tx_rx->tx_bits = 4;
furi_hal_nfc_tx_rx(tx_rx, 300);
}
return true;
}
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