115 lines
3.3 KiB
PHP
115 lines
3.3 KiB
PHP
<?php
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declare(strict_types=1);
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/*
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* The MIT License (MIT)
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*
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* Copyright (c) 2014-2019 Spomky-Labs
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*
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* This software may be modified and distributed under the terms
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* of the MIT license. See the LICENSE file for details.
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*/
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namespace OTPHP;
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use Assert\Assertion;
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use ParagonIE\ConstantTime\Base32;
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use RuntimeException;
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use function Safe\ksort;
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use function Safe\sprintf;
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abstract class OTP implements OTPInterface
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{
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use ParameterTrait;
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protected function __construct(?string $secret, string $digest, int $digits)
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{
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$this->setSecret($secret);
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$this->setDigest($digest);
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$this->setDigits($digits);
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}
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public function getQrCodeUri(string $uri, string $placeholder): string
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{
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$provisioning_uri = urlencode($this->getProvisioningUri());
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return str_replace($placeholder, $provisioning_uri, $uri);
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}
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/**
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* The OTP at the specified input.
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*/
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protected function generateOTP(int $input): string
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{
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$hash = hash_hmac($this->getDigest(), $this->intToByteString($input), $this->getDecodedSecret(), true);
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$hmac = array_values(unpack('C*', $hash));
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$offset = ($hmac[\count($hmac) - 1] & 0xF);
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$code = ($hmac[$offset + 0] & 0x7F) << 24 | ($hmac[$offset + 1] & 0xFF) << 16 | ($hmac[$offset + 2] & 0xFF) << 8 | ($hmac[$offset + 3] & 0xFF);
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$otp = $code % (10 ** $this->getDigits());
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return str_pad((string) $otp, $this->getDigits(), '0', STR_PAD_LEFT);
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}
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public function at(int $timestamp): string
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{
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return $this->generateOTP($timestamp);
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}
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/**
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* @param array<string, mixed> $options
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*/
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protected function filterOptions(array &$options): void
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{
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foreach (['algorithm' => 'sha1', 'period' => 30, 'digits' => 6] as $key => $default) {
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if (isset($options[$key]) && $default === $options[$key]) {
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unset($options[$key]);
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}
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}
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ksort($options);
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}
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/**
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* @param array<string, mixed> $options
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*/
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protected function generateURI(string $type, array $options): string
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{
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$label = $this->getLabel();
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Assertion::string($label, 'The label is not set.');
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Assertion::false($this->hasColon($label), 'Label must not contain a colon.');
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$options = array_merge($options, $this->getParameters());
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$this->filterOptions($options);
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$params = str_replace(['+', '%7E'], ['%20', '~'], http_build_query($options));
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return sprintf('otpauth://%s/%s?%s', $type, rawurlencode((null !== $this->getIssuer() ? $this->getIssuer().':' : '').$label), $params);
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}
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private function getDecodedSecret(): string
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{
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try {
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return Base32::decodeUpper($this->getSecret());
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} catch (\Exception $e) {
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throw new RuntimeException('Unable to decode the secret. Is it correctly base32 encoded?');
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}
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}
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private function intToByteString(int $int): string
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{
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$result = [];
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while (0 !== $int) {
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$result[] = \chr($int & 0xFF);
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$int >>= 8;
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}
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return str_pad(implode(array_reverse($result)), 8, "\000", STR_PAD_LEFT);
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}
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protected function compareOTP(string $safe, string $user): bool
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{
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return hash_equals($safe, $user);
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}
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}
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