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[FL-2876] MFC Improvements Part 2/2 (#1868)

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* 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>
This commit is contained in:
Astra 2022-10-13 19:23:29 +03:00 committed by GitHub
parent e46e6f8ee9
commit 55f8beef9f
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 93 additions and 30 deletions
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80
lib/nfc/nfc_worker.c
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@ -191,7 +191,7 @@ static bool nfc_worker_read_mf_classic(NfcWorker* nfc_worker, FuriHalNfcTxRxCont
uint8_t sectors_total =
mf_classic_get_total_sectors_num(nfc_worker->dev_data->mf_classic_data.type);
FURI_LOG_I(TAG, "Read %d sectors out of %d total", sectors_read, sectors_total);
read_success = (sectors_read == sectors_total);
read_success = mf_classic_is_card_read(&nfc_worker->dev_data->mf_classic_data);
}
} while(false);
@ -480,6 +480,9 @@ static void nfc_worker_mf_classic_key_attack(
uint16_t start_sector) {
furi_assert(nfc_worker);
bool card_found_notified = true;
bool card_removed_notified = false;
MfClassicData* data = &nfc_worker->dev_data->mf_classic_data;
uint32_t total_sectors = mf_classic_get_total_sectors_num(data->type);
@ -487,36 +490,52 @@ static void nfc_worker_mf_classic_key_attack(
// Check every sector's A and B keys with the given key
for(size_t i = start_sector; i < total_sectors; i++) {
uint8_t block_num = mf_classic_get_sector_trailer_block_num_by_sector(i);
if(mf_classic_is_sector_read(data, i)) continue;
if(!mf_classic_is_key_found(data, i, MfClassicKeyA)) {
FURI_LOG_D(
TAG,
"Trying A key for sector %d, key: %04lx%08lx",
i,
(uint32_t)(key >> 32),
(uint32_t)key);
if(mf_classic_authenticate(tx_rx, block_num, key, MfClassicKeyA)) {
mf_classic_set_key_found(data, i, MfClassicKeyA, key);
FURI_LOG_D(TAG, "Key found");
nfc_worker->callback(NfcWorkerEventFoundKeyA, nfc_worker->context);
furi_hal_nfc_sleep();
if(furi_hal_nfc_activate_nfca(200, NULL)) {
furi_hal_nfc_sleep();
if(!card_found_notified) {
nfc_worker->callback(NfcWorkerEventCardDetected, nfc_worker->context);
card_found_notified = true;
card_removed_notified = false;
}
uint8_t block_num = mf_classic_get_sector_trailer_block_num_by_sector(i);
if(mf_classic_is_sector_read(data, i)) continue;
if(!mf_classic_is_key_found(data, i, MfClassicKeyA)) {
FURI_LOG_D(
TAG,
"Trying A key for sector %d, key: %04lx%08lx",
i,
(uint32_t)(key >> 32),
(uint32_t)key);
if(mf_classic_authenticate(tx_rx, block_num, key, MfClassicKeyA)) {
mf_classic_set_key_found(data, i, MfClassicKeyA, key);
FURI_LOG_D(TAG, "Key found");
nfc_worker->callback(NfcWorkerEventFoundKeyA, nfc_worker->context);
}
}
if(!mf_classic_is_key_found(data, i, MfClassicKeyB)) {
FURI_LOG_D(
TAG,
"Trying B key for sector %d, key: %04lx%08lx",
i,
(uint32_t)(key >> 32),
(uint32_t)key);
if(mf_classic_authenticate(tx_rx, block_num, key, MfClassicKeyB)) {
mf_classic_set_key_found(data, i, MfClassicKeyB, key);
FURI_LOG_D(TAG, "Key found");
nfc_worker->callback(NfcWorkerEventFoundKeyB, nfc_worker->context);
}
}
if(mf_classic_is_sector_read(data, i)) continue;
mf_classic_read_sector(tx_rx, data, i);
} else {
if(!card_removed_notified) {
nfc_worker->callback(NfcWorkerEventNoCardDetected, nfc_worker->context);
card_removed_notified = true;
card_found_notified = false;
}
}
if(!mf_classic_is_key_found(data, i, MfClassicKeyB)) {
FURI_LOG_D(
TAG,
"Trying B key for sector %d, key: %04lx%08lx",
i,
(uint32_t)(key >> 32),
(uint32_t)key);
if(mf_classic_authenticate(tx_rx, block_num, key, MfClassicKeyB)) {
mf_classic_set_key_found(data, i, MfClassicKeyB, key);
FURI_LOG_D(TAG, "Key found");
nfc_worker->callback(NfcWorkerEventFoundKeyB, nfc_worker->context);
}
}
if(mf_classic_is_sector_read(data, i)) continue;
mf_classic_read_sector(tx_rx, data, i);
if(nfc_worker->state != NfcWorkerStateMfClassicDictAttack) break;
}
}
@ -530,6 +549,7 @@ void nfc_worker_mf_classic_dict_attack(NfcWorker* nfc_worker) {
&nfc_worker->dev_data->mf_classic_dict_attack_data;
uint32_t total_sectors = mf_classic_get_total_sectors_num(data->type);
uint64_t key = 0;
uint64_t prev_key = 0;
FuriHalNfcTxRxContext tx_rx = {};
bool card_found_notified = true;
bool card_removed_notified = false;
@ -564,6 +584,7 @@ void nfc_worker_mf_classic_dict_attack(NfcWorker* nfc_worker) {
nfc_worker->callback(NfcWorkerEventCardDetected, nfc_worker->context);
card_found_notified = true;
card_removed_notified = false;
nfc_worker_mf_classic_key_attack(nfc_worker, prev_key, &tx_rx, i);
}
FURI_LOG_D(
TAG,
@ -600,6 +621,7 @@ void nfc_worker_mf_classic_dict_attack(NfcWorker* nfc_worker) {
}
if(nfc_worker->state != NfcWorkerStateMfClassicDictAttack) break;
}
memcpy(&prev_key, &key, sizeof(key));
}
if(nfc_worker->state != NfcWorkerStateMfClassicDictAttack) break;
mf_classic_read_sector(&tx_rx, data, i);

39
lib/nfc/protocols/mifare_classic.c
View File

@ -155,6 +155,16 @@ void mf_classic_set_key_found(
}
}
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);
@ -203,6 +213,18 @@ void mf_classic_get_read_sectors_and_keys(
}
}
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,
@ -612,7 +634,15 @@ static bool mf_classic_read_sector_with_reader(
}
// Auth to first block in sector
if(!mf_classic_auth(tx_rx, first_block, key, key_type, crypto)) break;
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
@ -711,6 +741,13 @@ uint8_t mf_classic_update_card(FuriHalNfcTxRxContext* tx_rx, MfClassicData* data
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);
}
}
}
}

4
lib/nfc/protocols/mifare_classic.h
View File

@ -98,12 +98,16 @@ void mf_classic_set_key_found(
MfClassicKey key_type,
uint64_t key);
void mf_classic_set_key_not_found(MfClassicData* data, uint8_t sector_num, MfClassicKey key_type);
bool mf_classic_is_block_read(MfClassicData* data, uint8_t block_num);
void mf_classic_set_block_read(MfClassicData* data, uint8_t block_num, MfClassicBlock* block_data);
bool mf_classic_is_sector_read(MfClassicData* data, uint8_t sector_num);
bool mf_classic_is_card_read(MfClassicData* data);
void mf_classic_get_read_sectors_and_keys(
MfClassicData* data,
uint8_t* sectors_read,