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This commit is contained in:
Szczepan Zalega 2019-08-07 17:17:20 +02:00
parent 7be0553377
commit 5a448d636c
No known key found for this signature in database
GPG Key ID: D9BAE35991DE5B22
1 changed files with 8 additions and 1 deletions
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9
fido2/ctap.c
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@ -1285,11 +1285,13 @@ uint8_t ctap_update_pin_if_verified(uint8_t * pinEnc, int len, uint8_t * platfor
uint8_t hmac[32]; uint8_t hmac[32];
int ret; int ret;
// Validate incoming data packet len
if (len < 64) if (len < 64)
{ {
return CTAP1_ERR_OTHER; return CTAP1_ERR_OTHER;
} }
// Validate device's state
if (ctap_is_pin_set()) // Check first, prevent SCA if (ctap_is_pin_set()) // Check first, prevent SCA
{ {
if (ctap_device_locked()) if (ctap_device_locked())
@ -1302,6 +1304,7 @@ uint8_t ctap_update_pin_if_verified(uint8_t * pinEnc, int len, uint8_t * platfor
} }
} }
// calculate shared_secret
crypto_ecc256_shared_secret(platform_pubkey, KEY_AGREEMENT_PRIV, shared_secret); crypto_ecc256_shared_secret(platform_pubkey, KEY_AGREEMENT_PRIV, shared_secret);
crypto_sha256_init(); crypto_sha256_init();
@ -1324,6 +1327,7 @@ uint8_t ctap_update_pin_if_verified(uint8_t * pinEnc, int len, uint8_t * platfor
return CTAP2_ERR_PIN_AUTH_INVALID; return CTAP2_ERR_PIN_AUTH_INVALID;
} }
// decrypt new PIN with shared secret
crypto_aes256_init(shared_secret, NULL); crypto_aes256_init(shared_secret, NULL);
while((len & 0xf) != 0) // round up to nearest AES block size multiple while((len & 0xf) != 0) // round up to nearest AES block size multiple
@ -1333,7 +1337,7 @@ uint8_t ctap_update_pin_if_verified(uint8_t * pinEnc, int len, uint8_t * platfor
crypto_aes256_decrypt(pinEnc, len); crypto_aes256_decrypt(pinEnc, len);
// validate new PIN (length)
ret = trailing_zeros(pinEnc, NEW_PIN_ENC_MIN_SIZE - 1); ret = trailing_zeros(pinEnc, NEW_PIN_ENC_MIN_SIZE - 1);
ret = NEW_PIN_ENC_MIN_SIZE - ret; ret = NEW_PIN_ENC_MIN_SIZE - ret;
@ -1349,6 +1353,8 @@ uint8_t ctap_update_pin_if_verified(uint8_t * pinEnc, int len, uint8_t * platfor
dump_hex1(TAG_CP, pinEnc, ret); dump_hex1(TAG_CP, pinEnc, ret);
} }
// validate device's state, decrypt and compare pinHashEnc (user provided current PIN hash) with stored PIN_CODE_HASH
if (ctap_is_pin_set()) if (ctap_is_pin_set())
{ {
if (ctap_device_locked()) if (ctap_device_locked())
@ -1383,6 +1389,7 @@ uint8_t ctap_update_pin_if_verified(uint8_t * pinEnc, int len, uint8_t * platfor
} }
} }
// set new PIN (update and store PIN_CODE_HASH)
ctap_update_pin(pinEnc, ret); ctap_update_pin(pinEnc, ret);
return 0; return 0;