change the pin

This commit is contained in:
Conor Patrick 2018-05-22 20:42:34 -04:00
parent 6a94af0729
commit 35900455d5
4 changed files with 115 additions and 17 deletions

View File

@ -54,7 +54,7 @@ void crypto_sha256_final(uint8_t * hash)
sha256_final(&sha256_ctx, hash);
}
void crypto_sha256_hmac(uint8_t * key, uint32_t klen, uint8_t * data, uint32_t datalen, uint8_t * hmac)
void crypto_sha256_hmac_init(uint8_t * key, uint32_t klen, uint8_t * hmac)
{
uint8_t buf[64];
int i;
@ -75,10 +75,20 @@ void crypto_sha256_hmac(uint8_t * key, uint32_t klen, uint8_t * data, uint32_t d
crypto_sha256_init();
crypto_sha256_update(buf, 64);
crypto_sha256_update(data, datalen);
crypto_sha256_final(hmac);
}
void crypto_sha256_hmac_final(uint8_t * key, uint32_t klen, uint8_t * hmac)
{
uint8_t buf[64];
int i;
crypto_sha256_final(hmac);
memset(buf, 0, sizeof(buf));
if(klen > 64)
{
printf("Error, key size must be <= 64\n");
exit(1);
}
memmove(buf, key, klen);
for (i = 0; i < sizeof(buf); i++)
@ -92,6 +102,44 @@ void crypto_sha256_hmac(uint8_t * key, uint32_t klen, uint8_t * data, uint32_t d
crypto_sha256_final(hmac);
}
/*void crypto_sha256_hmac(uint8_t * key, uint32_t klen, uint8_t * data, uint32_t datalen, uint8_t * hmac)*/
/*{*/
/*uint8_t buf[64];*/
/*int i;*/
/*memset(buf, 0, sizeof(buf));*/
/*if(klen > 64)*/
/*{*/
/*printf("Error, key size must be <= 64\n");*/
/*exit(1);*/
/*}*/
/*memmove(buf, key, klen);*/
/*for (i = 0; i < sizeof(buf); i++)*/
/*{*/
/*buf[i] = buf[i] ^ 0x36;*/
/*}*/
/*crypto_sha256_init();*/
/*crypto_sha256_update(buf, 64);*/
/*crypto_sha256_update(data, datalen);*/
/*crypto_sha256_final(hmac);*/
/*memset(buf, 0, sizeof(buf));*/
/*memmove(buf, key, klen);*/
/*for (i = 0; i < sizeof(buf); i++)*/
/*{*/
/*buf[i] = buf[i] ^ 0x5c;*/
/*}*/
/*crypto_sha256_init();*/
/*crypto_sha256_update(buf, 64);*/
/*crypto_sha256_update(hmac, 32);*/
/*crypto_sha256_final(hmac);*/
/*}*/
void crypto_ecc256_init()
{

View File

@ -9,7 +9,9 @@ void crypto_sha256_update(uint8_t * data, size_t len);
void crypto_sha256_update_secret();
void crypto_sha256_final(uint8_t * hash);
void crypto_sha256_hmac(uint8_t * key, uint32_t klen, uint8_t * data, uint32_t datalen, uint8_t * hmac);
void crypto_sha256_hmac_init(uint8_t * key, uint32_t klen, uint8_t * hmac);
void crypto_sha256_hmac_final(uint8_t * key, uint32_t klen, uint8_t * hmac);
void crypto_ecc256_init();
void crypto_ecc256_derive_public_key(uint8_t * data, int len, uint8_t * x, uint8_t * y);

73
ctap.c
View File

@ -121,7 +121,10 @@ static const char * cbor_value_get_type_string(const CborValue *value)
uint8_t verify_pin_auth(uint8_t * pinAuth, uint8_t * clientDataHash)
{
uint8_t hmac[32];
crypto_sha256_hmac(PIN_TOKEN, PIN_TOKEN_SIZE, clientDataHash, CLIENT_DATA_HASH_SIZE, hmac);
crypto_sha256_hmac_init(PIN_TOKEN, PIN_TOKEN_SIZE, hmac);
crypto_sha256_update(clientDataHash, CLIENT_DATA_HASH_SIZE);
crypto_sha256_hmac_final(PIN_TOKEN, PIN_TOKEN_SIZE, hmac);
if (memcmp(pinAuth, hmac, 16) == 0)
{
@ -1695,7 +1698,7 @@ int ctap_parse_client_pin(CTAP_clientPin * CP, uint8_t * request, int length)
return 0;
}
uint8_t ctap_update_pin_if_verified(uint8_t * pinEnc, int len, uint8_t * platform_pubkey, uint8_t * pinAuth)
uint8_t ctap_update_pin_if_verified(uint8_t * pinEnc, int len, uint8_t * platform_pubkey, uint8_t * pinAuth, uint8_t * pinHashEnc)
{
uint8_t shared_secret[32];
uint8_t hmac[32];
@ -1706,18 +1709,19 @@ uint8_t ctap_update_pin_if_verified(uint8_t * pinEnc, int len, uint8_t * platfor
return CTAP1_ERR_OTHER;
}
if (ctap_is_pin_set())
{
return CTAP2_ERR_PIN_REQUIRED;
}
crypto_ecc256_shared_secret(platform_pubkey, KEY_AGREEMENT_PRIV, shared_secret);
crypto_sha256_init();
crypto_sha256_update(shared_secret, 32);
crypto_sha256_final(shared_secret);
crypto_sha256_hmac(shared_secret, 32, pinEnc, len, hmac);
crypto_sha256_hmac_init(shared_secret, 32, hmac);
crypto_sha256_update(pinEnc, len);
if (pinHashEnc != NULL)
{
crypto_sha256_update(pinHashEnc, 16);
}
crypto_sha256_hmac_final(shared_secret, 32, hmac);
if (memcmp(hmac, pinAuth, 16) != 0)
{
@ -1736,6 +1740,8 @@ uint8_t ctap_update_pin_if_verified(uint8_t * pinEnc, int len, uint8_t * platfor
crypto_aes256_decrypt(pinEnc, len);
printf("new pin: %s\n", pinEnc);
ret = strnlen(pinEnc, NEW_PIN_ENC_MAX_SIZE);
if (ret == NEW_PIN_ENC_MAX_SIZE)
{
@ -1747,11 +1753,25 @@ uint8_t ctap_update_pin_if_verified(uint8_t * pinEnc, int len, uint8_t * platfor
printf2(TAG_ERR,"new PIN is too short\n");
return CTAP2_ERR_PIN_POLICY_VIOLATION;
}
else
if (ctap_is_pin_set())
{
ctap_update_pin(pinEnc, ret);
crypto_aes256_reset_iv();
crypto_aes256_decrypt(pinHashEnc, 16);
if (memcmp(pinHashEnc, PIN_CODE_HASH, 16) != 0)
{
crypto_ecc256_make_key_pair(KEY_AGREEMENT_PUB, KEY_AGREEMENT_PRIV);
ctap_decrement_pin_attempts();
return CTAP2_ERR_PIN_INVALID;
}
else
{
ctap_reset_pin_attempts();
}
}
ctap_update_pin(pinEnc, ret);
return 0;
}
@ -1782,6 +1802,7 @@ uint8_t ctap_add_pin_if_verified(CborEncoder * map, uint8_t * platform_pubkey, u
return CTAP2_ERR_PIN_INVALID;
}
ctap_reset_pin_attempts();
crypto_aes256_reset_iv();
// reuse share_secret memory for encrypted pinToken
@ -1838,14 +1859,34 @@ uint8_t ctap_client_pin(CborEncoder * encoder, uint8_t * request, int length)
break;
case CP_cmdSetPin:
printf1(TAG_CP,"CP_cmdSetPin\n");
ret = ctap_update_pin_if_verified(CP.newPinEnc, CP.newPinEncSize, (uint8_t*)&CP.keyAgreement.pubkey, CP.pinAuth);
check_retr(ret);
if (ctap_is_pin_set())
{
return CTAP2_ERR_NOT_ALLOWED;
}
if (!CP.newPinEncSize || !CP.pinAuthPresent || !CP.keyAgreementPresent)
{
return CTAP2_ERR_MISSING_PARAMETER;
}
ret = ctap_update_pin_if_verified(CP.newPinEnc, CP.newPinEncSize, (uint8_t*)&CP.keyAgreement.pubkey, CP.pinAuth, NULL);
check_retr(ret);
break;
case CP_cmdChangePin:
printf1(TAG_CP,"CP_cmdChangePin\n");
return CTAP1_ERR_INVALID_COMMAND;
if (! ctap_is_pin_set())
{
return CTAP2_ERR_PIN_NOT_SET;
}
if (!CP.newPinEncSize || !CP.pinAuthPresent || !CP.keyAgreementPresent || !CP.pinHashEncPresent)
{
return CTAP2_ERR_MISSING_PARAMETER;
}
ret = ctap_update_pin_if_verified(CP.newPinEnc, CP.newPinEncSize, (uint8_t*)&CP.keyAgreement.pubkey, CP.pinAuth, CP.pinHashEnc);
check_retr(ret);
break;
case CP_cmdGetPinToken:
if (!ctap_is_pin_set())
@ -1992,6 +2033,12 @@ uint8_t ctap_is_pin_set()
return PIN_CODE_SET == 1;
}
uint8_t ctap_pin_matches(uint8_t * pin, int len)
{
return memcmp(pin, PIN_CODE, len) == 0;
}
void ctap_update_pin(uint8_t * pin, int len)
{
// TODO this should go in flash

1
ctap.h
View File

@ -228,6 +228,7 @@ uint8_t ctap_decrement_pin_attempts();
int8_t ctap_leftover_pin_attempts();
void ctap_reset_pin_attempts();
uint8_t ctap_is_pin_set();
uint8_t ctap_pin_matches(uint8_t * pin, int len);
// Test for user presence