[Web] FIDO2: Add Face ID via Apple

data/web/inc/lib/WebAuthn/Attestation/Format/Apple.php

@@ -0,0 +1,138 @@
+<?php
+
+
+namespace WebAuthn\Attestation\Format;
+use WebAuthn\WebAuthnException;
+use WebAuthn\Binary\ByteBuffer;
+
+class Apple extends FormatBase {
+    private $_x5c;
+
+    public function __construct($AttestionObject, \WebAuthn\Attestation\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);
+        $nonceExtension = isset($parsedCredCert['extensions']['1.2.840.113635.100.8.2']) ? $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;
+    }
+
+}
+