Project import generated by Copybara.
GitOrigin-RevId: 63746295f1a5ab5a619056791995793d65529e62
diff --git a/src/lib/WebAuthn/Attestation/Format/Apple.php b/src/lib/WebAuthn/Attestation/Format/Apple.php
new file mode 100644
index 0000000..e4f38e0
--- /dev/null
+++ b/src/lib/WebAuthn/Attestation/Format/Apple.php
@@ -0,0 +1,139 @@
+<?php
+
+
+namespace lbuchs\WebAuthn\Attestation\Format;
+use lbuchs\WebAuthn\Attestation\AuthenticatorData;
+use lbuchs\WebAuthn\WebAuthnException;
+use lbuchs\WebAuthn\Binary\ByteBuffer;
+
+class Apple extends FormatBase {
+ private $_x5c;
+
+ public function __construct($AttestionObject, AuthenticatorData $authenticatorData) {
+ parent::__construct($AttestionObject, $authenticatorData);
+
+ // check packed data
+ $attStmt = $this->_attestationObject['attStmt'];
+
+
+ // certificate for validation
+ if (\array_key_exists('x5c', $attStmt) && \is_array($attStmt['x5c']) && \count($attStmt['x5c']) > 0) {
+
+ // The attestation certificate attestnCert MUST be the first element in the array
+ $attestnCert = array_shift($attStmt['x5c']);
+
+ if (!($attestnCert instanceof ByteBuffer)) {
+ throw new WebAuthnException('invalid x5c certificate', WebAuthnException::INVALID_DATA);
+ }
+
+ $this->_x5c = $attestnCert->getBinaryString();
+
+ // certificate chain
+ foreach ($attStmt['x5c'] as $chain) {
+ if ($chain instanceof ByteBuffer) {
+ $this->_x5c_chain[] = $chain->getBinaryString();
+ }
+ }
+ } else {
+ throw new WebAuthnException('invalid Apple attestation statement: missing x5c', WebAuthnException::INVALID_DATA);
+ }
+ }
+
+
+ /*
+ * returns the key certificate in PEM format
+ * @return string|null
+ */
+ public function getCertificatePem() {
+ return $this->_createCertificatePem($this->_x5c);
+ }
+
+ /**
+ * @param string $clientDataHash
+ */
+ public function validateAttestation($clientDataHash) {
+ return $this->_validateOverX5c($clientDataHash);
+ }
+
+ /**
+ * validates the certificate against root certificates
+ * @param array $rootCas
+ * @return boolean
+ * @throws WebAuthnException
+ */
+ public function validateRootCertificate($rootCas) {
+ $chainC = $this->_createX5cChainFile();
+ if ($chainC) {
+ $rootCas[] = $chainC;
+ }
+
+ $v = \openssl_x509_checkpurpose($this->getCertificatePem(), -1, $rootCas);
+ if ($v === -1) {
+ throw new WebAuthnException('error on validating root certificate: ' . \openssl_error_string(), WebAuthnException::CERTIFICATE_NOT_TRUSTED);
+ }
+ return $v;
+ }
+
+ /**
+ * validate if x5c is present
+ * @param string $clientDataHash
+ * @return bool
+ * @throws WebAuthnException
+ */
+ protected function _validateOverX5c($clientDataHash) {
+ $publicKey = \openssl_pkey_get_public($this->getCertificatePem());
+
+ if ($publicKey === false) {
+ throw new WebAuthnException('invalid public key: ' . \openssl_error_string(), WebAuthnException::INVALID_PUBLIC_KEY);
+ }
+
+ // Concatenate authenticatorData and clientDataHash to form nonceToHash.
+ $nonceToHash = $this->_authenticatorData->getBinary();
+ $nonceToHash .= $clientDataHash;
+
+ // Perform SHA-256 hash of nonceToHash to produce nonce
+ $nonce = hash('SHA256', $nonceToHash, true);
+
+ $credCert = openssl_x509_read($this->getCertificatePem());
+ if ($credCert === false) {
+ throw new WebAuthnException('invalid x5c certificate: ' . \openssl_error_string(), WebAuthnException::INVALID_DATA);
+ }
+
+ $keyData = openssl_pkey_get_details(openssl_pkey_get_public($credCert));
+ $key = is_array($keyData) && array_key_exists('key', $keyData) ? $keyData['key'] : null;
+
+
+ // Verify that nonce equals the value of the extension with OID ( 1.2.840.113635.100.8.2 ) in credCert.
+ $parsedCredCert = openssl_x509_parse($credCert);
+ $nonceExtension = $parsedCredCert['extensions']['1.2.840.113635.100.8.2'] ?? '';
+
+ // nonce padded by ASN.1 string: 30 24 A1 22 04 20
+ // 30 — type tag indicating sequence
+ // 24 — 36 byte following
+ // A1 — Enumerated [1]
+ // 22 — 34 byte following
+ // 04 — type tag indicating octet string
+ // 20 — 32 byte following
+
+ $asn1Padding = "\x30\x24\xA1\x22\x04\x20";
+ if (substr($nonceExtension, 0, strlen($asn1Padding)) === $asn1Padding) {
+ $nonceExtension = substr($nonceExtension, strlen($asn1Padding));
+ }
+
+ if ($nonceExtension !== $nonce) {
+ throw new WebAuthnException('nonce doesn\'t equal the value of the extension with OID 1.2.840.113635.100.8.2', WebAuthnException::INVALID_DATA);
+ }
+
+ // Verify that the credential public key equals the Subject Public Key of credCert.
+ $authKeyData = openssl_pkey_get_details(openssl_pkey_get_public($this->_authenticatorData->getPublicKeyPem()));
+ $authKey = is_array($authKeyData) && array_key_exists('key', $authKeyData) ? $authKeyData['key'] : null;
+
+ if ($key === null || $key !== $authKey) {
+ throw new WebAuthnException('credential public key doesn\'t equal the Subject Public Key of credCert', WebAuthnException::INVALID_DATA);
+ }
+
+ return true;
+ }
+
+}
+