| <?php |
| |
| namespace WebAuthn; |
| use WebAuthn\Binary\ByteBuffer; |
| require_once 'WebAuthnException.php'; |
| require_once 'Binary/ByteBuffer.php'; |
| require_once 'Attestation/AttestationObject.php'; |
| require_once 'Attestation/AuthenticatorData.php'; |
| require_once 'Attestation/Format/FormatBase.php'; |
| require_once 'Attestation/Format/None.php'; |
| require_once 'Attestation/Format/AndroidKey.php'; |
| require_once 'Attestation/Format/AndroidSafetyNet.php'; |
| require_once 'Attestation/Format/Apple.php'; |
| require_once 'Attestation/Format/Packed.php'; |
| require_once 'Attestation/Format/Tpm.php'; |
| require_once 'Attestation/Format/U2f.php'; |
| require_once 'CBOR/CborDecoder.php'; |
| |
| /** |
| * WebAuthn |
| * @author Lukas Buchs |
| * @license https://github.com/lbuchs/WebAuthn/blob/master/LICENSE MIT |
| */ |
| class WebAuthn { |
| // relying party |
| private $_rpName; |
| private $_rpId; |
| private $_rpIdHash; |
| private $_challenge; |
| private $_signatureCounter; |
| private $_caFiles; |
| private $_formats; |
| |
| /** |
| * Initialize a new WebAuthn server |
| * @param string $rpName the relying party name |
| * @param string $rpId the relying party ID = the domain name |
| * @param bool $useBase64UrlEncoding true to use base64 url encoding for binary data in json objects. Default is a RFC 1342-Like serialized string. |
| * @throws WebAuthnException |
| */ |
| public function __construct($rpName, $rpId, $allowedFormats=null, $useBase64UrlEncoding=false) { |
| $this->_rpName = $rpName; |
| $this->_rpId = $rpId; |
| $this->_rpIdHash = \hash('sha256', $rpId, true); |
| ByteBuffer::$useBase64UrlEncoding = !!$useBase64UrlEncoding; |
| $supportedFormats = array('android-key', 'android-safetynet', 'apple', 'fido-u2f', 'none', 'packed', 'tpm'); |
| |
| if (!\function_exists('\openssl_open')) { |
| throw new WebAuthnException('OpenSSL-Module not installed');; |
| } |
| |
| if (!\in_array('SHA256', \array_map('\strtoupper', \openssl_get_md_methods()))) { |
| throw new WebAuthnException('SHA256 not supported by this openssl installation.'); |
| } |
| |
| // default: all format |
| if (!is_array($allowedFormats)) { |
| $allowedFormats = $supportedFormats; |
| } |
| $this->_formats = $allowedFormats; |
| |
| // validate formats |
| $invalidFormats = \array_diff($this->_formats, $supportedFormats); |
| if (!$this->_formats || $invalidFormats) { |
| throw new WebAuthnException('invalid formats on construct: ' . implode(', ', $invalidFormats)); |
| } |
| } |
| |
| /** |
| * add a root certificate to verify new registrations |
| * @param string $path file path of / directory with root certificates |
| */ |
| public function addRootCertificates($path) { |
| if (!\is_array($this->_caFiles)) { |
| $this->_caFiles = array(); |
| } |
| $path = \rtrim(\trim($path), '\\/'); |
| if (\is_dir($path)) { |
| foreach (\scandir($path) as $ca) { |
| if (\is_file($path . '/' . $ca)) { |
| $this->addRootCertificates($path . '/' . $ca); |
| } |
| } |
| } else if (\is_file($path) && !\in_array(\realpath($path), $this->_caFiles)) { |
| $this->_caFiles[] = \realpath($path); |
| } |
| } |
| |
| /** |
| * Returns the generated challenge to save for later validation |
| * @return ByteBuffer |
| */ |
| public function getChallenge() { |
| return $this->_challenge; |
| } |
| |
| /** |
| * generates the object for a key registration |
| * provide this data to navigator.credentials.create |
| * @param string $userId |
| * @param string $userName |
| * @param string $userDisplayName |
| * @param int $timeout timeout in seconds |
| * @param bool $requireResidentKey true, if the key should be stored by the authentication device |
| * @param bool|string $requireUserVerification indicates that you require user verification and will fail the operation |
| * if the response does not have the UV flag set. |
| * Valid values: |
| * true = required |
| * false = preferred |
| * string 'required' 'preferred' 'discouraged' |
| * @param bool|null $crossPlatformAttachment true for cross-platform devices (eg. fido usb), |
| * false for platform devices (eg. windows hello, android safetynet), |
| * null for both |
| * @param array $excludeCredentialIds a array of ids, which are already registered, to prevent re-registration |
| * @return \stdClass |
| */ |
| public function getCreateArgs($userId, $userName, $userDisplayName, $timeout=20, $requireResidentKey=false, $requireUserVerification=false, $crossPlatformAttachment=null, $excludeCredentialIds=array()) { |
| |
| // validate User Verification Requirement |
| if (\is_bool($requireUserVerification)) { |
| $requireUserVerification = $requireUserVerification ? 'required' : 'preferred'; |
| } else if (\is_string($requireUserVerification) && \in_array(\strtolower($requireUserVerification), ['required', 'preferred', 'discouraged'])) { |
| $requireUserVerification = \strtolower($requireUserVerification); |
| } else { |
| $requireUserVerification = 'preferred'; |
| } |
| |
| $args = new \stdClass(); |
| $args->publicKey = new \stdClass(); |
| |
| // relying party |
| $args->publicKey->rp = new \stdClass(); |
| $args->publicKey->rp->name = $this->_rpName; |
| $args->publicKey->rp->id = $this->_rpId; |
| |
| $args->publicKey->authenticatorSelection = new \stdClass(); |
| $args->publicKey->authenticatorSelection->userVerification = $requireUserVerification; |
| if ($requireResidentKey) { |
| $args->publicKey->authenticatorSelection->requireResidentKey = true; |
| } |
| if (is_bool($crossPlatformAttachment)) { |
| $args->publicKey->authenticatorSelection->authenticatorAttachment = $crossPlatformAttachment ? 'cross-platform' : 'platform'; |
| } |
| |
| // user |
| $args->publicKey->user = new \stdClass(); |
| $args->publicKey->user->id = new ByteBuffer($userId); // binary |
| $args->publicKey->user->name = $userName; |
| $args->publicKey->user->displayName = $userDisplayName; |
| |
| $args->publicKey->pubKeyCredParams = array(); |
| $tmp = new \stdClass(); |
| $tmp->type = 'public-key'; |
| $tmp->alg = -7; // ES256 |
| $args->publicKey->pubKeyCredParams[] = $tmp; |
| unset ($tmp); |
| |
| $tmp = new \stdClass(); |
| $tmp->type = 'public-key'; |
| $tmp->alg = -257; // RS256 |
| $args->publicKey->pubKeyCredParams[] = $tmp; |
| unset ($tmp); |
| |
| // if there are root certificates added, we need direct attestation to validate |
| // against the root certificate. If there are no root-certificates added, |
| // anonymization ca are also accepted, because we can't validate the root anyway. |
| $attestation = 'indirect'; |
| if (\is_array($this->_caFiles)) { |
| $attestation = 'direct'; |
| } |
| |
| $args->publicKey->attestation = \count($this->_formats) === 1 && \in_array('none', $this->_formats) ? 'none' : $attestation; |
| $args->publicKey->extensions = new \stdClass(); |
| $args->publicKey->extensions->exts = true; |
| $args->publicKey->timeout = $timeout * 1000; // microseconds |
| $args->publicKey->challenge = $this->_createChallenge(); // binary |
| |
| //prevent re-registration by specifying existing credentials |
| $args->publicKey->excludeCredentials = array(); |
| |
| if (is_array($excludeCredentialIds)) { |
| foreach ($excludeCredentialIds as $id) { |
| $tmp = new \stdClass(); |
| $tmp->id = $id instanceof ByteBuffer ? $id : new ByteBuffer($id); // binary |
| $tmp->type = 'public-key'; |
| $tmp->transports = array('usb', 'ble', 'nfc', 'internal'); |
| $args->publicKey->excludeCredentials[] = $tmp; |
| unset ($tmp); |
| } |
| } |
| |
| return $args; |
| } |
| |
| /** |
| * generates the object for key validation |
| * Provide this data to navigator.credentials.get |
| * @param array $credentialIds binary |
| * @param int $timeout timeout in seconds |
| * @param bool $allowUsb allow removable USB |
| * @param bool $allowNfc allow Near Field Communication (NFC) |
| * @param bool $allowBle allow Bluetooth |
| * @param bool $allowInternal allow client device-specific transport. These authenticators are not removable from the client device. |
| * @param bool|string $requireUserVerification indicates that you require user verification and will fail the operation |
| * if the response does not have the UV flag set. |
| * Valid values: |
| * true = required |
| * false = preferred |
| * string 'required' 'preferred' 'discouraged' |
| * @return \stdClass |
| */ |
| public function getGetArgs($credentialIds=array(), $timeout=20, $allowUsb=true, $allowNfc=true, $allowBle=true, $allowInternal=true, $requireUserVerification=false) { |
| |
| // validate User Verification Requirement |
| if (\is_bool($requireUserVerification)) { |
| $requireUserVerification = $requireUserVerification ? 'required' : 'preferred'; |
| } else if (\is_string($requireUserVerification) && \in_array(\strtolower($requireUserVerification), ['required', 'preferred', 'discouraged'])) { |
| $requireUserVerification = \strtolower($requireUserVerification); |
| } else { |
| $requireUserVerification = 'preferred'; |
| } |
| |
| $args = new \stdClass(); |
| $args->publicKey = new \stdClass(); |
| $args->publicKey->timeout = $timeout * 1000; // microseconds |
| $args->publicKey->challenge = $this->_createChallenge(); // binary |
| $args->publicKey->userVerification = $requireUserVerification; |
| $args->publicKey->rpId = $this->_rpId; |
| |
| if (\is_array($credentialIds) && \count($credentialIds) > 0) { |
| $args->publicKey->allowCredentials = array(); |
| |
| foreach ($credentialIds as $id) { |
| $tmp = new \stdClass(); |
| $tmp->id = $id instanceof ByteBuffer ? $id : new ByteBuffer($id); // binary |
| $tmp->transports = array(); |
| |
| if ($allowUsb) { |
| $tmp->transports[] = 'usb'; |
| } |
| if ($allowNfc) { |
| $tmp->transports[] = 'nfc'; |
| } |
| if ($allowBle) { |
| $tmp->transports[] = 'ble'; |
| } |
| if ($allowInternal) { |
| $tmp->transports[] = 'internal'; |
| } |
| |
| $tmp->type = 'public-key'; |
| $args->publicKey->allowCredentials[] = $tmp; |
| unset ($tmp); |
| } |
| } |
| |
| return $args; |
| } |
| |
| /** |
| * returns the new signature counter value. |
| * returns null if there is no counter |
| * @return ?int |
| */ |
| public function getSignatureCounter() { |
| return \is_int($this->_signatureCounter) ? $this->_signatureCounter : null; |
| } |
| |
| /** |
| * process a create request and returns data to save for future logins |
| * @param string $clientDataJSON binary from browser |
| * @param string $attestationObject binary from browser |
| * @param string|ByteBuffer $challenge binary used challange |
| * @param bool $requireUserVerification true, if the device must verify user (e.g. by biometric data or pin) |
| * @param bool $requireUserPresent false, if the device must NOT check user presence (e.g. by pressing a button) |
| * @return \stdClass |
| * @throws WebAuthnException |
| */ |
| public function processCreate($clientDataJSON, $attestationObject, $challenge, $requireUserVerification=false, $requireUserPresent=true) { |
| $clientDataHash = \hash('sha256', $clientDataJSON, true); |
| $clientData = \json_decode($clientDataJSON); |
| $challenge = $challenge instanceof ByteBuffer ? $challenge : new ByteBuffer($challenge); |
| |
| // security: https://www.w3.org/TR/webauthn/#registering-a-new-credential |
| |
| // 2. Let C, the client data claimed as collected during the credential creation, |
| // be the result of running an implementation-specific JSON parser on JSONtext. |
| if (!\is_object($clientData)) { |
| throw new WebAuthnException('invalid client data', WebAuthnException::INVALID_DATA); |
| } |
| |
| // 3. Verify that the value of C.type is webauthn.create. |
| if (!\property_exists($clientData, 'type') || $clientData->type !== 'webauthn.create') { |
| throw new WebAuthnException('invalid type', WebAuthnException::INVALID_TYPE); |
| } |
| |
| // 4. Verify that the value of C.challenge matches the challenge that was sent to the authenticator in the create() call. |
| if (!\property_exists($clientData, 'challenge') || ByteBuffer::fromBase64Url($clientData->challenge)->getBinaryString() !== $challenge->getBinaryString()) { |
| throw new WebAuthnException('invalid challenge', WebAuthnException::INVALID_CHALLENGE); |
| } |
| |
| // 5. Verify that the value of C.origin matches the Relying Party's origin. |
| if (!\property_exists($clientData, 'origin') || !$this->_checkOrigin($clientData->origin)) { |
| throw new WebAuthnException('invalid origin', WebAuthnException::INVALID_ORIGIN); |
| } |
| |
| // Attestation |
| $attestationObject = new Attestation\AttestationObject($attestationObject, $this->_formats); |
| |
| // 9. Verify that the RP ID hash in authData is indeed the SHA-256 hash of the RP ID expected by the RP. |
| if (!$attestationObject->validateRpIdHash($this->_rpIdHash)) { |
| throw new WebAuthnException('invalid rpId hash', WebAuthnException::INVALID_RELYING_PARTY); |
| } |
| |
| // 14. Verify that attStmt is a correct attestation statement, conveying a valid attestation signature |
| if (!$attestationObject->validateAttestation($clientDataHash)) { |
| throw new WebAuthnException('invalid certificate signature', WebAuthnException::INVALID_SIGNATURE); |
| } |
| |
| // 15. If validation is successful, obtain a list of acceptable trust anchors |
| if (is_array($this->_caFiles) && !$attestationObject->validateRootCertificate($this->_caFiles)) { |
| throw new WebAuthnException('invalid root certificate', WebAuthnException::CERTIFICATE_NOT_TRUSTED); |
| } |
| |
| // 10. Verify that the User Present bit of the flags in authData is set. |
| if ($requireUserPresent && !$attestationObject->getAuthenticatorData()->getUserPresent()) { |
| throw new WebAuthnException('user not present during authentication', WebAuthnException::USER_PRESENT); |
| } |
| |
| // 11. If user verification is required for this registration, verify that the User Verified bit of the flags in authData is set. |
| if ($requireUserVerification && !$attestationObject->getAuthenticatorData()->getUserVerified()) { |
| throw new WebAuthnException('user not verificated during authentication', WebAuthnException::USER_VERIFICATED); |
| } |
| |
| $signCount = $attestationObject->getAuthenticatorData()->getSignCount(); |
| if ($signCount > 0) { |
| $this->_signatureCounter = $signCount; |
| } |
| |
| // prepare data to store for future logins |
| $data = new \stdClass(); |
| $data->rpId = $this->_rpId; |
| $data->credentialId = $attestationObject->getAuthenticatorData()->getCredentialId(); |
| $data->credentialPublicKey = $attestationObject->getAuthenticatorData()->getPublicKeyPem(); |
| $data->certificateChain = $attestationObject->getCertificateChain(); |
| $data->certificate = $attestationObject->getCertificatePem(); |
| $data->certificateIssuer = $attestationObject->getCertificateIssuer(); |
| $data->certificateSubject = $attestationObject->getCertificateSubject(); |
| $data->signatureCounter = $this->_signatureCounter; |
| $data->AAGUID = $attestationObject->getAuthenticatorData()->getAAGUID(); |
| return $data; |
| } |
| |
| |
| /** |
| * process a get request |
| * @param string $clientDataJSON binary from browser |
| * @param string $authenticatorData binary from browser |
| * @param string $signature binary from browser |
| * @param string $credentialPublicKey string PEM-formated public key from used credentialId |
| * @param string|ByteBuffer $challenge binary from used challange |
| * @param int $prevSignatureCnt signature count value of the last login |
| * @param bool $requireUserVerification true, if the device must verify user (e.g. by biometric data or pin) |
| * @param bool $requireUserPresent true, if the device must check user presence (e.g. by pressing a button) |
| * @return boolean true if get is successful |
| * @throws WebAuthnException |
| */ |
| public function processGet($clientDataJSON, $authenticatorData, $signature, $credentialPublicKey, $challenge, $prevSignatureCnt=null, $requireUserVerification=false, $requireUserPresent=true) { |
| $authenticatorObj = new Attestation\AuthenticatorData($authenticatorData); |
| $clientDataHash = \hash('sha256', $clientDataJSON, true); |
| $clientData = \json_decode($clientDataJSON); |
| $challenge = $challenge instanceof ByteBuffer ? $challenge : new ByteBuffer($challenge); |
| |
| // https://www.w3.org/TR/webauthn/#verifying-assertion |
| |
| // 1. If the allowCredentials option was given when this authentication ceremony was initiated, |
| // verify that credential.id identifies one of the public key credentials that were listed in allowCredentials. |
| // -> TO BE VERIFIED BY IMPLEMENTATION |
| |
| // 2. If credential.response.userHandle is present, verify that the user identified |
| // by this value is the owner of the public key credential identified by credential.id. |
| // -> TO BE VERIFIED BY IMPLEMENTATION |
| |
| // 3. Using credential’s id attribute (or the corresponding rawId, if base64url encoding is |
| // inappropriate for your use case), look up the corresponding credential public key. |
| // -> TO BE LOOKED UP BY IMPLEMENTATION |
| |
| // 5. Let JSONtext be the result of running UTF-8 decode on the value of cData. |
| if (!\is_object($clientData)) { |
| throw new WebAuthnException('invalid client data', WebAuthnException::INVALID_DATA); |
| } |
| |
| // 7. Verify that the value of C.type is the string webauthn.get. |
| if (!\property_exists($clientData, 'type') || $clientData->type !== 'webauthn.get') { |
| throw new WebAuthnException('invalid type', WebAuthnException::INVALID_TYPE); |
| } |
| |
| // 8. Verify that the value of C.challenge matches the challenge that was sent to the |
| // authenticator in the PublicKeyCredentialRequestOptions passed to the get() call. |
| if (!\property_exists($clientData, 'challenge') || ByteBuffer::fromBase64Url($clientData->challenge)->getBinaryString() !== $challenge->getBinaryString()) { |
| throw new WebAuthnException('invalid challenge', WebAuthnException::INVALID_CHALLENGE); |
| } |
| |
| // 9. Verify that the value of C.origin matches the Relying Party's origin. |
| if (!\property_exists($clientData, 'origin') || !$this->_checkOrigin($clientData->origin)) { |
| throw new WebAuthnException('invalid origin', WebAuthnException::INVALID_ORIGIN); |
| } |
| |
| // 11. Verify that the rpIdHash in authData is the SHA-256 hash of the RP ID expected by the Relying Party. |
| if ($authenticatorObj->getRpIdHash() !== $this->_rpIdHash) { |
| throw new WebAuthnException('invalid rpId hash', WebAuthnException::INVALID_RELYING_PARTY); |
| } |
| |
| // 12. Verify that the User Present bit of the flags in authData is set |
| if ($requireUserPresent && !$authenticatorObj->getUserPresent()) { |
| throw new WebAuthnException('user not present during authentication', WebAuthnException::USER_PRESENT); |
| } |
| |
| // 13. If user verification is required for this assertion, verify that the User Verified bit of the flags in authData is set. |
| if ($requireUserVerification && !$authenticatorObj->getUserVerified()) { |
| throw new WebAuthnException('user not verificated during authentication', WebAuthnException::USER_VERIFICATED); |
| } |
| |
| // 14. Verify the values of the client extension outputs |
| // (extensions not implemented) |
| |
| // 16. Using the credential public key looked up in step 3, verify that sig is a valid signature |
| // over the binary concatenation of authData and hash. |
| $dataToVerify = ''; |
| $dataToVerify .= $authenticatorData; |
| $dataToVerify .= $clientDataHash; |
| |
| $publicKey = \openssl_pkey_get_public($credentialPublicKey); |
| if ($publicKey === false) { |
| throw new WebAuthnException('public key invalid', WebAuthnException::INVALID_PUBLIC_KEY); |
| } |
| |
| if (\openssl_verify($dataToVerify, $signature, $publicKey, OPENSSL_ALGO_SHA256) !== 1) { |
| throw new WebAuthnException('invalid signature', WebAuthnException::INVALID_SIGNATURE); |
| } |
| |
| // 17. If the signature counter value authData.signCount is nonzero, |
| // if less than or equal to the signature counter value stored, |
| // is a signal that the authenticator may be cloned |
| $signatureCounter = $authenticatorObj->getSignCount(); |
| if ($signatureCounter > 0) { |
| $this->_signatureCounter = $signatureCounter; |
| if ($prevSignatureCnt !== null && $prevSignatureCnt >= $signatureCounter) { |
| throw new WebAuthnException('signature counter not valid', WebAuthnException::SIGNATURE_COUNTER); |
| } |
| } |
| |
| return true; |
| } |
| |
| // ----------------------------------------------- |
| // PRIVATE |
| // ----------------------------------------------- |
| |
| /** |
| * checks if the origin matchs the RP ID |
| * @param string $origin |
| * @return boolean |
| * @throws WebAuthnException |
| */ |
| private function _checkOrigin($origin) { |
| // https://www.w3.org/TR/webauthn/#rp-id |
| |
| // The origin's scheme must be https |
| if ($this->_rpId !== 'localhost' && \parse_url($origin, PHP_URL_SCHEME) !== 'https') { |
| return false; |
| } |
| |
| // extract host from origin |
| $host = \parse_url($origin, PHP_URL_HOST); |
| $host = \trim($host, '.'); |
| |
| // The RP ID must be equal to the origin's effective domain, or a registrable |
| // domain suffix of the origin's effective domain. |
| return \preg_match('/' . \preg_quote($this->_rpId) . '$/i', $host) === 1; |
| } |
| |
| /** |
| * generates a new challange |
| * @param int $length |
| * @return string |
| * @throws WebAuthnException |
| */ |
| private function _createChallenge($length = 32) { |
| if (!$this->_challenge) { |
| $this->_challenge = ByteBuffer::randomBuffer($length); |
| } |
| return $this->_challenge; |
| } |
| } |