498 lines
19 KiB
PHP
498 lines
19 KiB
PHP
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<?php
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declare(strict_types=1);
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namespace PhpMyAdmin\WebAuthn;
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use Psr\Http\Message\ServerRequestInterface;
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use SodiumException;
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use Throwable;
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use Webmozart\Assert\Assert;
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use Webmozart\Assert\InvalidArgumentException;
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use function hash;
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use function hash_equals;
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use function json_decode;
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use function mb_strlen;
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use function mb_substr;
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use function ord;
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use function parse_url;
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use function random_bytes;
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use function sodium_base642bin;
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use function sodium_bin2base64;
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use function unpack;
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use const PHP_URL_HOST;
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use const SODIUM_BASE64_VARIANT_ORIGINAL;
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use const SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING;
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/**
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* Web Authentication API server.
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*
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* @see https://www.w3.org/TR/webauthn-3/
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* @see https://developer.mozilla.org/en-US/docs/Web/API/Web_Authentication_API
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* @see https://webauthn.guide/
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*/
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final class CustomServer implements Server
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{
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public function getCredentialCreationOptions(string $userName, string $userId, string $relyingPartyId): array
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{
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return [
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'challenge' => $this->generateChallenge(),
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'rp' => ['name' => 'phpMyAdmin (' . $relyingPartyId . ')', 'id' => $relyingPartyId],
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'user' => ['id' => $userId, 'name' => $userName, 'displayName' => $userName],
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'pubKeyCredParams' => $this->getCredentialParameters(),
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'authenticatorSelection' => [
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'authenticatorAttachment' => 'cross-platform',
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'userVerification' => 'discouraged',
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],
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'timeout' => 60000,
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'attestation' => 'none',
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];
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}
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public function getCredentialRequestOptions(
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string $userName,
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string $userId,
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string $relyingPartyId,
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array $allowedCredentials
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): array {
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foreach ($allowedCredentials as $key => $credential) {
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$allowedCredentials[$key]['id'] = sodium_bin2base64(
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sodium_base642bin($credential['id'], SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING),
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SODIUM_BASE64_VARIANT_ORIGINAL
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);
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}
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return [
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'challenge' => $this->generateChallenge(),
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'allowCredentials' => $allowedCredentials,
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'timeout' => 60000,
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'attestation' => 'none',
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'userVerification' => 'discouraged',
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];
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}
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public function parseAndValidateAssertionResponse(
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string $assertionResponseJson,
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array $allowedCredentials,
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string $challenge,
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ServerRequestInterface $request
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): void {
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$assertionCredential = $this->getAssertionCredential($assertionResponseJson);
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if ($allowedCredentials !== []) {
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Assert::true($this->isCredentialIdAllowed($assertionCredential['rawId'], $allowedCredentials));
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}
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$authenticatorData = $this->getAuthenticatorData($assertionCredential['response']['authenticatorData']);
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$clientData = $this->getCollectedClientData($assertionCredential['response']['clientDataJSON']);
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Assert::same($clientData['type'], 'webauthn.get');
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try {
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$knownChallenge = sodium_base642bin($challenge, SODIUM_BASE64_VARIANT_ORIGINAL);
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$cDataChallenge = sodium_base642bin($clientData['challenge'], SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING);
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} catch (SodiumException $exception) {
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throw new WebAuthnException((string) $exception);
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}
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Assert::true(hash_equals($knownChallenge, $cDataChallenge));
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$host = $request->getUri()->getHost();
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Assert::same($host, parse_url($clientData['origin'], PHP_URL_HOST));
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$rpIdHash = hash('sha256', $host, true);
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Assert::true(hash_equals($rpIdHash, $authenticatorData['rpIdHash']));
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$isUserPresent = (ord($authenticatorData['flags']) & 1) !== 0;
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Assert::true($isUserPresent);
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}
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public function parseAndValidateAttestationResponse(
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string $attestationResponse,
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string $credentialCreationOptions,
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ServerRequestInterface $request
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): array {
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try {
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$attestationCredential = $this->getAttestationCredential($attestationResponse);
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} catch (Throwable $exception) {
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throw new WebAuthnException('Invalid authenticator response.');
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}
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$creationOptions = json_decode($credentialCreationOptions, true);
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Assert::isArray($creationOptions);
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Assert::keyExists($creationOptions, 'challenge');
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Assert::string($creationOptions['challenge']);
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Assert::keyExists($creationOptions, 'user');
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Assert::isArray($creationOptions['user']);
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Assert::keyExists($creationOptions['user'], 'id');
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Assert::string($creationOptions['user']['id']);
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$clientData = $this->getCollectedClientData($attestationCredential['response']['clientDataJSON']);
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// Verify that the value of C.type is webauthn.create.
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Assert::same($clientData['type'], 'webauthn.create');
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// Verify that the value of C.challenge equals the base64url encoding of options.challenge.
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$optionsChallenge = sodium_base642bin($creationOptions['challenge'], SODIUM_BASE64_VARIANT_ORIGINAL);
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$clientDataChallenge = sodium_base642bin($clientData['challenge'], SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING);
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Assert::true(hash_equals($optionsChallenge, $clientDataChallenge));
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// Verify that the value of C.origin matches the Relying Party's origin.
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$host = $request->getUri()->getHost();
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Assert::same($host, parse_url($clientData['origin'], PHP_URL_HOST), 'Invalid origin.');
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// Perform CBOR decoding on the attestationObject field.
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$attestationObject = $this->getAttestationObject($attestationCredential['response']['attestationObject']);
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$authenticatorData = $this->getAuthenticatorData($attestationObject['authData']);
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Assert::notNull($authenticatorData['attestedCredentialData']);
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// Verify that the rpIdHash in authData is the SHA-256 hash of the RP ID expected by the Relying Party.
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$rpIdHash = hash('sha256', $host, true);
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Assert::true(hash_equals($rpIdHash, $authenticatorData['rpIdHash']), 'Invalid rpIdHash.');
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// Verify that the User Present bit of the flags in authData is set.
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$isUserPresent = (ord($authenticatorData['flags']) & 1) !== 0;
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Assert::true($isUserPresent);
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Assert::same($attestationObject['fmt'], 'none');
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Assert::same($attestationObject['attStmt'], []);
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$encodedCredentialId = sodium_bin2base64(
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$authenticatorData['attestedCredentialData']['credentialId'],
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SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING
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);
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$encodedCredentialPublicKey = sodium_bin2base64(
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$authenticatorData['attestedCredentialData']['credentialPublicKey'],
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SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING
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);
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$userHandle = sodium_bin2base64(
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sodium_base642bin($creationOptions['user']['id'], SODIUM_BASE64_VARIANT_ORIGINAL),
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SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING
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);
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return [
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'publicKeyCredentialId' => $encodedCredentialId,
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'type' => 'public-key',
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'transports' => [],
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'attestationType' => $attestationObject['fmt'],
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'aaguid' => $authenticatorData['attestedCredentialData']['aaguid'],
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'credentialPublicKey' => $encodedCredentialPublicKey,
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'userHandle' => $userHandle,
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'counter' => $authenticatorData['signCount'],
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];
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}
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/**
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* In order to prevent replay attacks, the challenges MUST contain enough entropy to make guessing them infeasible.
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* Challenges SHOULD therefore be at least 16 bytes long.
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*
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* @see https://www.w3.org/TR/webauthn-3/#sctn-cryptographic-challenges
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*
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* @psalm-return non-empty-string
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*
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* @throws WebAuthnException
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*/
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private function generateChallenge(): string
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{
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try {
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return sodium_bin2base64(random_bytes(32), SODIUM_BASE64_VARIANT_ORIGINAL);
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} catch (Throwable $throwable) { // @codeCoverageIgnore
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throw new WebAuthnException('Error when generating challenge.'); // @codeCoverageIgnore
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}
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}
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/**
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* @see https://www.w3.org/TR/webauthn-3/#sctn-authenticator-data
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*
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* @psalm-return array{
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* rpIdHash: string,
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* flags: string,
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* signCount: int,
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* attestedCredentialData: array{
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* aaguid: string,
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* credentialId: string,
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* credentialPublicKey: string,
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* credentialPublicKeyDecoded: mixed[]
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* }|null,
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* extensions: string|null
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* }
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*
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* @throws WebAuthnException
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*/
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private function getAuthenticatorData(string $authData): array
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{
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$authDataLength = mb_strlen($authData, '8bit');
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Assert::true($authDataLength >= 37);
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$authDataStream = new DataStream($authData);
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$rpIdHash = $authDataStream->take(32);
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$flags = $authDataStream->take(1);
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// 32-bit unsigned big-endian integer
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$unpackedSignCount = unpack('N', $authDataStream->take(4));
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Assert::isArray($unpackedSignCount);
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Assert::keyExists($unpackedSignCount, 1);
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Assert::integer($unpackedSignCount[1]);
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$signCount = $unpackedSignCount[1];
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$attestedCredentialData = null;
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// Bit 6: Attested credential data included (AT).
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if ((ord($flags) & 64) !== 0) {
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/** Authenticator Attestation GUID */
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$aaguid = $authDataStream->take(16);
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// 16-bit unsigned big-endian integer
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$unpackedCredentialIdLength = unpack('n', $authDataStream->take(2));
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Assert::isArray($unpackedCredentialIdLength);
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Assert::keyExists($unpackedCredentialIdLength, 1);
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Assert::integer($unpackedCredentialIdLength[1]);
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$credentialIdLength = $unpackedCredentialIdLength[1];
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$credentialId = $authDataStream->take($credentialIdLength);
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$credentialPublicKeyDecoded = (new CBORDecoder())->decode($authDataStream);
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Assert::isArray($credentialPublicKeyDecoded);
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$credentialPublicKey = mb_substr(
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$authData,
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37 + 18 + $credentialIdLength,
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$authDataStream->getPosition(),
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'8bit'
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);
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$attestedCredentialData = [
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'aaguid' => $aaguid,
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'credentialId' => $credentialId,
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'credentialPublicKey' => $credentialPublicKey,
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'credentialPublicKeyDecoded' => $credentialPublicKeyDecoded,
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];
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}
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return [
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'rpIdHash' => $rpIdHash,
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'flags' => $flags,
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'signCount' => $signCount,
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'attestedCredentialData' => $attestedCredentialData,
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'extensions' => null,
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];
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}
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/**
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* @psalm-param non-empty-string $id
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* @psalm-param list<array{id: non-empty-string, type: non-empty-string}> $allowedCredentials
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*
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* @throws WebAuthnException
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*/
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private function isCredentialIdAllowed(string $id, array $allowedCredentials): bool
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{
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foreach ($allowedCredentials as $credential) {
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try {
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$credentialId = sodium_base642bin($credential['id'], SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING);
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} catch (SodiumException $exception) {
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throw new WebAuthnException();
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}
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if (hash_equals($credentialId, $id)) {
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return true;
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}
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}
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return false;
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}
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/**
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* @see https://www.iana.org/assignments/cose/cose.xhtml#algorithms
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*
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* @psalm-return list<array{alg: int, type: 'public-key'}>
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*/
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private function getCredentialParameters(): array
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{
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return [
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['alg' => -257, 'type' => 'public-key'], // RS256
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['alg' => -259, 'type' => 'public-key'], // RS512
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['alg' => -37, 'type' => 'public-key'], // PS256
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['alg' => -39, 'type' => 'public-key'], // PS512
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['alg' => -7, 'type' => 'public-key'], // ES256
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['alg' => -36, 'type' => 'public-key'], // ES512
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['alg' => -8, 'type' => 'public-key'], // EdDSA
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];
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}
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/**
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* @psalm-param non-empty-string $assertionResponseJson
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*
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* @psalm-return array{
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* id: non-empty-string,
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* type: 'public-key',
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* rawId: non-empty-string,
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* response: array{
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* clientDataJSON: non-empty-string,
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* authenticatorData: non-empty-string,
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* signature: non-empty-string,
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* }
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* }
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*
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* @throws SodiumException
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* @throws InvalidArgumentException
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*/
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private function getAssertionCredential(string $assertionResponseJson): array
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{
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$credential = json_decode($assertionResponseJson, true);
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Assert::isArray($credential);
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Assert::keyExists($credential, 'id');
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Assert::stringNotEmpty($credential['id']);
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Assert::keyExists($credential, 'type');
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Assert::same($credential['type'], 'public-key');
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Assert::keyExists($credential, 'rawId');
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Assert::stringNotEmpty($credential['rawId']);
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Assert::keyExists($credential, 'response');
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Assert::isArray($credential['response']);
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Assert::keyExists($credential['response'], 'clientDataJSON');
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Assert::stringNotEmpty($credential['response']['clientDataJSON']);
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Assert::keyExists($credential['response'], 'authenticatorData');
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Assert::stringNotEmpty($credential['response']['authenticatorData']);
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Assert::keyExists($credential['response'], 'signature');
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Assert::stringNotEmpty($credential['response']['signature']);
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$id = sodium_base642bin($credential['id'], SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING);
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$rawId = sodium_base642bin($credential['rawId'], SODIUM_BASE64_VARIANT_ORIGINAL);
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Assert::stringNotEmpty($id);
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Assert::stringNotEmpty($rawId);
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Assert::true(hash_equals($rawId, $id));
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$clientDataJSON = sodium_base642bin($credential['response']['clientDataJSON'], SODIUM_BASE64_VARIANT_ORIGINAL);
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Assert::stringNotEmpty($clientDataJSON);
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$authenticatorData = sodium_base642bin(
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$credential['response']['authenticatorData'],
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SODIUM_BASE64_VARIANT_ORIGINAL
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);
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Assert::stringNotEmpty($authenticatorData);
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$signature = sodium_base642bin($credential['response']['signature'], SODIUM_BASE64_VARIANT_ORIGINAL);
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Assert::stringNotEmpty($signature);
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return [
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'id' => $credential['id'],
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'type' => 'public-key',
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'rawId' => $rawId,
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'response' => [
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'clientDataJSON' => $clientDataJSON,
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'authenticatorData' => $authenticatorData,
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'signature' => $signature,
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],
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];
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}
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/**
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* @see https://www.w3.org/TR/webauthn-3/#iface-authenticatorattestationresponse
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*
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* @psalm-param non-empty-string $attestationResponse
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*
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* @psalm-return array{
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* id: non-empty-string,
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* rawId: non-empty-string,
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* type: 'public-key',
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* response: array{clientDataJSON: non-empty-string, attestationObject: non-empty-string}
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* }
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*
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* @throws SodiumException
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* @throws InvalidArgumentException
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*/
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private function getAttestationCredential(string $attestationResponse): array
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{
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$credential = json_decode($attestationResponse, true);
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Assert::isArray($credential);
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Assert::keyExists($credential, 'id');
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Assert::stringNotEmpty($credential['id']);
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|
Assert::keyExists($credential, 'rawId');
|
||
|
Assert::stringNotEmpty($credential['rawId']);
|
||
|
Assert::keyExists($credential, 'type');
|
||
|
Assert::string($credential['type']);
|
||
|
Assert::same($credential['type'], 'public-key');
|
||
|
Assert::keyExists($credential, 'response');
|
||
|
Assert::isArray($credential['response']);
|
||
|
Assert::keyExists($credential['response'], 'clientDataJSON');
|
||
|
Assert::stringNotEmpty($credential['response']['clientDataJSON']);
|
||
|
Assert::keyExists($credential['response'], 'attestationObject');
|
||
|
Assert::stringNotEmpty($credential['response']['attestationObject']);
|
||
|
|
||
|
$id = sodium_base642bin($credential['id'], SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING);
|
||
|
$rawId = sodium_base642bin($credential['rawId'], SODIUM_BASE64_VARIANT_ORIGINAL);
|
||
|
Assert::stringNotEmpty($id);
|
||
|
Assert::stringNotEmpty($rawId);
|
||
|
Assert::true(hash_equals($rawId, $id));
|
||
|
|
||
|
$clientDataJSON = sodium_base642bin($credential['response']['clientDataJSON'], SODIUM_BASE64_VARIANT_ORIGINAL);
|
||
|
Assert::stringNotEmpty($clientDataJSON);
|
||
|
$attestationObject = sodium_base642bin(
|
||
|
$credential['response']['attestationObject'],
|
||
|
SODIUM_BASE64_VARIANT_ORIGINAL
|
||
|
);
|
||
|
Assert::stringNotEmpty($attestationObject);
|
||
|
|
||
|
return [
|
||
|
'id' => $credential['id'],
|
||
|
'rawId' => $rawId,
|
||
|
'type' => 'public-key',
|
||
|
'response' => [
|
||
|
'clientDataJSON' => $clientDataJSON,
|
||
|
'attestationObject' => $attestationObject,
|
||
|
],
|
||
|
];
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* @see https://www.w3.org/TR/webauthn-3/#dictionary-client-data
|
||
|
*
|
||
|
* @psalm-param non-empty-string $clientDataJSON
|
||
|
*
|
||
|
* @return array{
|
||
|
* type: 'webauthn.create'|'webauthn.get',
|
||
|
* challenge: non-empty-string,
|
||
|
* origin: non-empty-string
|
||
|
* }
|
||
|
*/
|
||
|
private function getCollectedClientData(string $clientDataJSON): array
|
||
|
{
|
||
|
$clientData = json_decode($clientDataJSON, true);
|
||
|
|
||
|
Assert::isArray($clientData);
|
||
|
Assert::keyExists($clientData, 'type');
|
||
|
Assert::stringNotEmpty($clientData['type']);
|
||
|
Assert::inArray($clientData['type'], ['webauthn.create', 'webauthn.get']);
|
||
|
Assert::keyExists($clientData, 'challenge');
|
||
|
Assert::stringNotEmpty($clientData['challenge']);
|
||
|
Assert::keyExists($clientData, 'origin');
|
||
|
Assert::stringNotEmpty($clientData['origin']);
|
||
|
|
||
|
return [
|
||
|
'type' => $clientData['type'],
|
||
|
'challenge' => $clientData['challenge'],
|
||
|
'origin' => $clientData['origin'],
|
||
|
];
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* @psalm-param non-empty-string $attestationObjectEncoded
|
||
|
*
|
||
|
* @psalm-return array{fmt: string, attStmt: mixed[], authData: string}
|
||
|
*
|
||
|
* @throws WebAuthnException
|
||
|
*/
|
||
|
private function getAttestationObject(string $attestationObjectEncoded): array
|
||
|
{
|
||
|
$decoded = (new CBORDecoder())->decode(new DataStream($attestationObjectEncoded));
|
||
|
|
||
|
Assert::isArray($decoded);
|
||
|
Assert::keyExists($decoded, 'fmt');
|
||
|
Assert::string($decoded['fmt']);
|
||
|
Assert::keyExists($decoded, 'attStmt');
|
||
|
Assert::isArray($decoded['attStmt']);
|
||
|
Assert::keyExists($decoded, 'authData');
|
||
|
Assert::string($decoded['authData']);
|
||
|
|
||
|
return $decoded;
|
||
|
}
|
||
|
}
|