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Port miLazyCracker patch: test PRNG

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cf 39658a2ac4/mfoc_test_prng.diff
This commit is contained in:
Philippe Teuwen 2017-02-17 15:41:22 +01:00
parent 2316ad0815
commit 34d42e5e47
1 changed files with 97 additions and 6 deletions
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103
src/mfoc.c
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@ -65,6 +65,48 @@ static const nfc_modulation nm = {
nfc_context *context;
uint64_t knownKey = 0;
char knownKeyLetter = 'A';
uint32_t knownSector = 0;
uint32_t unknownSector = 0;
char unknownKeyLetter = 'A';
uint32_t unexpected_random = 0;
// Determine the distance between two nonces.
// Assume that the difference is small, but we don't know which is first.
// Therefore try in alternating directions.
int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
if (nt1 == nt2) return 0;
uint16_t i;
uint32_t nttmp1 = nt1;
uint32_t nttmp2 = nt2;
for (i = 1; i < (32768/8); ++i) {
nttmp1 = prng_successor(nttmp1, 1); if (nttmp1 == nt2) return i;
nttmp2 = prng_successor(nttmp2, 1); if (nttmp2 == nt1) return -i;
nttmp1 = prng_successor(nttmp1, 1); if (nttmp1 == nt2) return i+1;
nttmp2 = prng_successor(nttmp2, 1); if (nttmp2 == nt1) return -(i+1);
nttmp1 = prng_successor(nttmp1, 1); if (nttmp1 == nt2) return i+2;
nttmp2 = prng_successor(nttmp2, 1); if (nttmp2 == nt1) return -(i+2);
nttmp1 = prng_successor(nttmp1, 1); if (nttmp1 == nt2) return i+3;
nttmp2 = prng_successor(nttmp2, 1); if (nttmp2 == nt1) return -(i+3);
nttmp1 = prng_successor(nttmp1, 1); if (nttmp1 == nt2) return i+4;
nttmp2 = prng_successor(nttmp2, 1); if (nttmp2 == nt1) return -(i+4);
nttmp1 = prng_successor(nttmp1, 1); if (nttmp1 == nt2) return i+5;
nttmp2 = prng_successor(nttmp2, 1); if (nttmp2 == nt1) return -(i+5);
nttmp1 = prng_successor(nttmp1, 1); if (nttmp1 == nt2) return i+6;
nttmp2 = prng_successor(nttmp2, 1); if (nttmp2 == nt1) return -(i+6);
nttmp1 = prng_successor(nttmp1, 1); if (nttmp1 == nt2) return i+7;
nttmp2 = prng_successor(nttmp2, 1); if (nttmp2 == nt1) return -(i+7);
}
// either nt1 or nt2 are invalid nonces
return(-99999);
}
int main(int argc, char *const argv[])
{
int ch, i, k, n, j, m;
@ -119,6 +161,7 @@ int main(int argc, char *const argv[])
mifare_cmd mc;
FILE *pfDump = NULL;
FILE *pfKey = NULL;
//File pointers for the keyfile
FILE * fp;
@ -199,6 +242,14 @@ int main(int argc, char *const argv[])
}
// fprintf(stdout, "Output file: %s\n", optarg);
break;
case 'D':
// Partial File output
if (!(pfKey = fopen(optarg, "w"))) {
fprintf(stderr, "Cannot open: %s, exiting\n", optarg);
exit(EXIT_FAILURE);
}
// fprintf(stdout, "Output file: %s\n", optarg);
break;
case 'h':
usage(stdout, 0);
break;
@ -427,14 +478,28 @@ int main(int argc, char *const argv[])
fprintf(stdout, "\n");
for (i = 0; i < (t.num_sectors); ++i) {
if(t.sectors[i].foundKeyA)
if(t.sectors[i].foundKeyA){
fprintf(stdout, "Sector %02d - Found Key A: %012llx ", i, bytes_to_num(t.sectors[i].KeyA, sizeof(t.sectors[i].KeyA)));
else
memcpy(&knownKey, t.sectors[i].KeyA, 6);
knownKeyLetter = 'A';
knownSector = i;
}
else{
fprintf(stdout, "Sector %02d - Unknown Key A ", i);
if(t.sectors[i].foundKeyB)
unknownSector = i;
unknownKeyLetter = 'A';
}
if(t.sectors[i].foundKeyB){
fprintf(stdout, "Found Key B: %012llx\n", bytes_to_num(t.sectors[i].KeyB, sizeof(t.sectors[i].KeyB)));
else
knownKeyLetter = 'B';
memcpy(&knownKey, t.sectors[i].KeyB, 6);
knownSector = i;
}
else{
fprintf(stdout, "Unknown Key B\n");
unknownSector = i;
unknownKeyLetter = 'B';
}
}
fflush(stdout);
@ -510,7 +575,18 @@ int main(int argc, char *const argv[])
// Max probes for auth for each sector
for (k = 0; k < probes; ++k) {
// Try to authenticate to exploit sector and determine distances (filling denonce.distances)
mf_enhanced_auth(e_sector, 0, t, r, &d, pk, 'd', dumpKeysA); // AUTH + Get Distances mode
int authresult = mf_enhanced_auth(e_sector, 0, t, r, &d, pk, 'd', dumpKeysA); // AUTH + Get Distances mode
if(authresult == -99999){
//for now we return the last sector that is unknown
nfc_close(r.pdi);
nfc_exit(context);
if(pfKey) {
fprintf(pfKey, "%012llx;%d;%c;%d;%c", knownKey, knownSector, knownKeyLetter, unknownSector, unknownKeyLetter);
fclose(pfKey);
}
return 9;
}
printf("Sector: %d, type %c, probe %d, distance %d ", j, (dumpKeysA ? 'A' : 'B'), k, d.median);
// Configure device to the previous state
mf_configure(r.pdi);
@ -726,6 +802,7 @@ void usage(FILE *stream, int errno)
fprintf(stream, " T nonce tolerance half-range, instead of default of 20\n (i.e., 40 for the total range, in both directions)\n");
// fprintf(stream, " s specify the list of sectors to crack, for example -s 0,1,3,5\n");
fprintf(stream, " O file in which the card contents will be written (REQUIRED)\n");
fprintf(stream, " D file in which partial card info will be written in case PRNG is not vulnerable\n");
fprintf(stream, "\n");
fprintf(stream, "Example: mfoc -O mycard.mfd\n");
fprintf(stream, "Example: mfoc -k ffffeeeedddd -O mycard.mfd\n");
@ -1018,7 +1095,21 @@ int mf_enhanced_auth(int e_sector, int a_sector, mftag t, mfreader r, denonce *d
// Save the determined nonces distance
d->distances[m] = nonce_distance(Nt, NtLast);
// fprintf(stdout, "distance: %05d\n", d->distances[m]);
int checkForValidPRNG = dist_nt(Nt, NtLast);
//printf("NT distance: %d\n", checkForValidPRNG);
// if no distance between, then we are in sync.
if (checkForValidPRNG == 0) {
printf("NT Distance is zero..........\n");
} else {
if (checkForValidPRNG == -99999) { // invalid nonce received
++unexpected_random;
if (unexpected_random > 4) {
printf("PRNG is not vulnerable to nested attack\n");
return -99999;
}
}
}
// Again, prepare and send {At}
for (i = 0; i < 4; i++) {