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Fix valid_nonce

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noproto
2024-08-11 14:30:26 -04:00
parent 3acba77070
commit 6332ec7478
6 changed files with 18 additions and 18 deletions
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lib/nfc/helpers/crypto1.c
+7 -12
View File
@@ -207,16 +207,11 @@ uint32_t lfsr_rollback_word(Crypto1* crypto1, uint32_t in, int fb) {
}
// Return true if the nonce is invalid else return false
bool valid_nonce(uint32_t Nt, uint32_t NtEnc, uint32_t Ks1, uint8_t parity) {
return ((nfc_util_odd_parity8((Nt >> 24) & 0xFF) ==
(((parity >> 3) & 1) ^ nfc_util_odd_parity8((NtEnc >> 24) & 0xFF) ^
FURI_BIT(Ks1, 16))) &&
(nfc_util_odd_parity8((Nt >> 16) & 0xFF) ==
(((parity >> 2) & 1) ^ nfc_util_odd_parity8((NtEnc >> 16) & 0xFF) ^
FURI_BIT(Ks1, 8))) &&
(nfc_util_odd_parity8((Nt >> 8) & 0xFF) ==
(((parity >> 1) & 1) ^ nfc_util_odd_parity8((NtEnc >> 8) & 0xFF) ^
FURI_BIT(Ks1, 0)))) ?
true :
false;
bool valid_nonce(uint32_t nt, uint32_t ks, uint8_t nt_par_enc) {
return (nfc_util_even_parity8((nt >> 24) & 0xFF) ==
(((nt_par_enc >> 3) & 1) ^ FURI_BIT(ks, 16))) &&
(nfc_util_even_parity8((nt >> 16) & 0xFF) ==
(((nt_par_enc >> 2) & 1) ^ FURI_BIT(ks, 8))) &&
(nfc_util_even_parity8((nt >> 8) & 0xFF) ==
(((nt_par_enc >> 1) & 1) ^ FURI_BIT(ks, 0)));
}
lib/nfc/helpers/crypto1.h
+1 -1
View File
@@ -40,7 +40,7 @@ void crypto1_encrypt_reader_nonce(
uint32_t lfsr_rollback_word(Crypto1* crypto1, uint32_t in, int fb);
bool valid_nonce(uint32_t Nt, uint32_t NtEnc, uint32_t Ks1, uint8_t parity);
bool valid_nonce(uint32_t nt, uint32_t ks, uint8_t nt_par_enc);
uint32_t prng_successor(uint32_t x, uint32_t n);
lib/nfc/helpers/nfc_util.c
+4
View File
@@ -13,6 +13,10 @@ static const uint8_t nfc_util_odd_byte_parity[256] = {
0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1};
uint8_t nfc_util_even_parity8(uint8_t data) {
return !nfc_util_odd_byte_parity[data];
}
uint8_t nfc_util_even_parity32(uint32_t data) {
// data ^= data >> 16;
// data ^= data >> 8;
lib/nfc/helpers/nfc_util.h
+2
View File
@@ -6,6 +6,8 @@
extern "C" {
#endif
uint8_t nfc_util_even_parity8(uint8_t data);
uint8_t nfc_util_even_parity32(uint32_t data);
uint8_t nfc_util_odd_parity8(uint8_t data);
lib/nfc/protocols/mf_classic/mf_classic_poller.c
+2 -4
View File
@@ -1250,8 +1250,7 @@ NfcCommand mf_classic_poller_handler_nested_collect_nt_enc(MfClassicPoller* inst
((dict_attack_ctx->d_median + current_dist) != UINT16_MAX)) {
uint32_t nth_successor_positive =
prng_successor(decrypted_nt_prev, dict_attack_ctx->d_median + current_dist);
if(valid_nonce(
nth_successor_positive, nt_enc, nth_successor_positive ^ nt_enc, parity)) {
if(valid_nonce(nth_successor_positive, nth_successor_positive ^ nt_enc, parity)) {
found_matching_nt = true;
found_nt = nth_successor_positive;
break;
@@ -1259,8 +1258,7 @@ NfcCommand mf_classic_poller_handler_nested_collect_nt_enc(MfClassicPoller* inst
if(current_dist > 0) {
uint32_t nth_successor_negative =
prng_successor(decrypted_nt_prev, dict_attack_ctx->d_median - current_dist);
if(valid_nonce(
nth_successor_negative, nt_enc, nth_successor_negative ^ nt_enc, parity)) {
if(valid_nonce(nth_successor_negative, nth_successor_negative ^ nt_enc, parity)) {
found_matching_nt = true;
found_nt = nth_successor_negative;
break;