Copybara bot | be50d49 | 2023-11-30 00:16:42 +0100 | [diff] [blame^] | 1 | <?php |
| 2 | |
| 3 | |
| 4 | namespace lbuchs\WebAuthn\Attestation\Format; |
| 5 | use lbuchs\WebAuthn\Attestation\AuthenticatorData; |
| 6 | use lbuchs\WebAuthn\WebAuthnException; |
| 7 | use lbuchs\WebAuthn\Binary\ByteBuffer; |
| 8 | |
| 9 | class Packed extends FormatBase { |
| 10 | private $_alg; |
| 11 | private $_signature; |
| 12 | private $_x5c; |
| 13 | |
| 14 | public function __construct($AttestionObject, AuthenticatorData $authenticatorData) { |
| 15 | parent::__construct($AttestionObject, $authenticatorData); |
| 16 | |
| 17 | // check packed data |
| 18 | $attStmt = $this->_attestationObject['attStmt']; |
| 19 | |
| 20 | if (!\array_key_exists('alg', $attStmt) || $this->_getCoseAlgorithm($attStmt['alg']) === null) { |
| 21 | throw new WebAuthnException('unsupported alg: ' . $attStmt['alg'], WebAuthnException::INVALID_DATA); |
| 22 | } |
| 23 | |
| 24 | if (!\array_key_exists('sig', $attStmt) || !\is_object($attStmt['sig']) || !($attStmt['sig'] instanceof ByteBuffer)) { |
| 25 | throw new WebAuthnException('no signature found', WebAuthnException::INVALID_DATA); |
| 26 | } |
| 27 | |
| 28 | $this->_alg = $attStmt['alg']; |
| 29 | $this->_signature = $attStmt['sig']->getBinaryString(); |
| 30 | |
| 31 | // certificate for validation |
| 32 | if (\array_key_exists('x5c', $attStmt) && \is_array($attStmt['x5c']) && \count($attStmt['x5c']) > 0) { |
| 33 | |
| 34 | // The attestation certificate attestnCert MUST be the first element in the array |
| 35 | $attestnCert = array_shift($attStmt['x5c']); |
| 36 | |
| 37 | if (!($attestnCert instanceof ByteBuffer)) { |
| 38 | throw new WebAuthnException('invalid x5c certificate', WebAuthnException::INVALID_DATA); |
| 39 | } |
| 40 | |
| 41 | $this->_x5c = $attestnCert->getBinaryString(); |
| 42 | |
| 43 | // certificate chain |
| 44 | foreach ($attStmt['x5c'] as $chain) { |
| 45 | if ($chain instanceof ByteBuffer) { |
| 46 | $this->_x5c_chain[] = $chain->getBinaryString(); |
| 47 | } |
| 48 | } |
| 49 | } |
| 50 | } |
| 51 | |
| 52 | |
| 53 | /* |
| 54 | * returns the key certificate in PEM format |
| 55 | * @return string|null |
| 56 | */ |
| 57 | public function getCertificatePem() { |
| 58 | if (!$this->_x5c) { |
| 59 | return null; |
| 60 | } |
| 61 | return $this->_createCertificatePem($this->_x5c); |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * @param string $clientDataHash |
| 66 | */ |
| 67 | public function validateAttestation($clientDataHash) { |
| 68 | if ($this->_x5c) { |
| 69 | return $this->_validateOverX5c($clientDataHash); |
| 70 | } else { |
| 71 | return $this->_validateSelfAttestation($clientDataHash); |
| 72 | } |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * validates the certificate against root certificates |
| 77 | * @param array $rootCas |
| 78 | * @return boolean |
| 79 | * @throws WebAuthnException |
| 80 | */ |
| 81 | public function validateRootCertificate($rootCas) { |
| 82 | if (!$this->_x5c) { |
| 83 | return false; |
| 84 | } |
| 85 | |
| 86 | $chainC = $this->_createX5cChainFile(); |
| 87 | if ($chainC) { |
| 88 | $rootCas[] = $chainC; |
| 89 | } |
| 90 | |
| 91 | $v = \openssl_x509_checkpurpose($this->getCertificatePem(), -1, $rootCas); |
| 92 | if ($v === -1) { |
| 93 | throw new WebAuthnException('error on validating root certificate: ' . \openssl_error_string(), WebAuthnException::CERTIFICATE_NOT_TRUSTED); |
| 94 | } |
| 95 | return $v; |
| 96 | } |
| 97 | |
| 98 | /** |
| 99 | * validate if x5c is present |
| 100 | * @param string $clientDataHash |
| 101 | * @return bool |
| 102 | * @throws WebAuthnException |
| 103 | */ |
| 104 | protected function _validateOverX5c($clientDataHash) { |
| 105 | $publicKey = \openssl_pkey_get_public($this->getCertificatePem()); |
| 106 | |
| 107 | if ($publicKey === false) { |
| 108 | throw new WebAuthnException('invalid public key: ' . \openssl_error_string(), WebAuthnException::INVALID_PUBLIC_KEY); |
| 109 | } |
| 110 | |
| 111 | // Verify that sig is a valid signature over the concatenation of authenticatorData and clientDataHash |
| 112 | // using the attestation public key in attestnCert with the algorithm specified in alg. |
| 113 | $dataToVerify = $this->_authenticatorData->getBinary(); |
| 114 | $dataToVerify .= $clientDataHash; |
| 115 | |
| 116 | $coseAlgorithm = $this->_getCoseAlgorithm($this->_alg); |
| 117 | |
| 118 | // check certificate |
| 119 | return \openssl_verify($dataToVerify, $this->_signature, $publicKey, $coseAlgorithm->openssl) === 1; |
| 120 | } |
| 121 | |
| 122 | /** |
| 123 | * validate if self attestation is in use |
| 124 | * @param string $clientDataHash |
| 125 | * @return bool |
| 126 | */ |
| 127 | protected function _validateSelfAttestation($clientDataHash) { |
| 128 | // Verify that sig is a valid signature over the concatenation of authenticatorData and clientDataHash |
| 129 | // using the credential public key with alg. |
| 130 | $dataToVerify = $this->_authenticatorData->getBinary(); |
| 131 | $dataToVerify .= $clientDataHash; |
| 132 | |
| 133 | $publicKey = $this->_authenticatorData->getPublicKeyPem(); |
| 134 | |
| 135 | // check certificate |
| 136 | return \openssl_verify($dataToVerify, $this->_signature, $publicKey, OPENSSL_ALGO_SHA256) === 1; |
| 137 | } |
| 138 | } |
| 139 | |