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improve hf 14a info (#457)

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* added validate_prng_nonce from iceman1001 fork
* added DetectClassicPrng from iceman1001 fork
This commit is contained in:
Oleg Moiseenko 2017-11-01 18:48:59 +02:00 • committed by pwpiwi
commit fe6bf3c58c
4 changed files with 85 additions and 1 deletions
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69
client/mifarehost.c
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@ -903,3 +903,72 @@ int tryDecryptWord(uint32_t nt, uint32_t ar_enc, uint32_t at_enc, uint8_t *data,
return 0;
}
/** validate_prng_nonce
* Determine if nonce is deterministic. ie: Suspectable to Darkside attack.
* returns
* true = weak prng
* false = hardend prng
*/
bool validate_prng_nonce(uint32_t nonce) {
uint16_t *dist = 0;
uint16_t x, i;
dist = malloc(2 << 16);
if(!dist)
return -1;
// init prng table:
for (x = i = 1; i; ++i) {
dist[(x & 0xff) << 8 | x >> 8] = i;
x = x >> 1 | (x ^ x >> 2 ^ x >> 3 ^ x >> 5) << 15;
}
uint32_t res = (65535 - dist[nonce >> 16] + dist[nonce & 0xffff]) % 65535;
free(dist);
return (res == 16);
}
/* Detect Tag Prng,
* function performs a partial AUTH, where it tries to authenticate against block0, key A, but only collects tag nonce.
* the tag nonce is check to see if it has a predictable PRNG.
* @returns
* TRUE if tag uses WEAK prng (ie Now the NACK bug also needs to be present for Darkside attack)
* FALSE is tag uses HARDEND prng (ie hardnested attack possible, with known key)
*/
int DetectClassicPrng(void){
UsbCommand resp, respA;
uint8_t cmd[] = {0x60, 0x00}; // MIFARE_AUTH_KEYA
uint32_t flags = ISO14A_CONNECT | ISO14A_RAW | ISO14A_APPEND_CRC | ISO14A_NO_RATS;
UsbCommand c = {CMD_READER_ISO_14443a, {flags, sizeof(cmd), 0}};
memcpy(c.d.asBytes, cmd, sizeof(cmd));
clearCommandBuffer();
SendCommand(&c);
if (!WaitForResponseTimeout(CMD_ACK, &resp, 2000)) {
PrintAndLog("PRNG UID: Reply timeout.");
return -1;
}
// if select tag failed.
if (resp.arg[0] == 0) {
PrintAndLog("PRNG error: selecting tag failed, can't detect prng.");
return -1;
}
if (!WaitForResponseTimeout(CMD_ACK, &respA, 5000)) {
PrintAndLog("PRNG data: Reply timeout.");
return -1;
}
// check respA
if (respA.arg[0] != 4) {
PrintAndLog("PRNG data error: Wrong length: %d", respA.arg[0]);
return -1;
}
uint32_t nonce = bytes_to_num(respA.d.asBytes, respA.arg[0]);
return validate_prng_nonce(nonce);
}