84 lines
2.4 KiB
PHP
84 lines
2.4 KiB
PHP
<?php
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declare(strict_types=1);
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namespace App\Services;
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final class TotpService
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{
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private const ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';
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public function generateSecret(): string
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{
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$secret = '';
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for ($i = 0; $i < 16; $i++) {
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$secret .= self::ALPHABET[random_int(0, 31)];
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}
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return $secret;
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}
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public function verify(string $secret, string $code): bool
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{
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$currentTime = floor(time() / 30);
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// Check current, previous and next window (allow 30s clock drift)
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for ($i = -1; $i <= 1; $i++) {
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if ($this->calculateCode($secret, (int)($currentTime + $i)) === $code) {
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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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private function calculateCode(string $secret, int $time): string
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{
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$key = $this->base32Decode($secret);
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$timeHex = str_pad(dechex($time), 16, '0', STR_PAD_LEFT);
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$timeBin = pack('H*', $timeHex);
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$hash = hash_hmac('sha1', $timeBin, $key, true);
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$offset = ord($hash[19]) & 0xf;
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$otp = (
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((ord($hash[$offset]) & 0x7f) << 24) |
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((ord($hash[$offset + 1]) & 0xff) << 16) |
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((ord($hash[$offset + 2]) & 0xff) << 8) |
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(ord($hash[$offset + 3]) & 0xff)
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) % 1000000;
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return str_pad((string)$otp, 6, '0', STR_PAD_LEFT);
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}
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private function base32Decode(string $base32): string
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{
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$base32 = strtoupper($base32);
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$buffer = 0;
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$bufferSize = 0;
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$decoded = '';
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for ($i = 0; $i < strlen($base32); $i++) {
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$char = $base32[$i];
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$pos = strpos(self::ALPHABET, $char);
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if ($pos === false) continue;
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$buffer = ($buffer << 5) | $pos;
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$bufferSize += 5;
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if ($bufferSize >= 8) {
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$bufferSize -= 8;
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$decoded .= chr(($buffer >> $bufferSize) & 0xff);
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}
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}
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return $decoded;
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}
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public function getQrCodeUrl(string $userEmail, string $secret, string $issuer = 'Musadaq'): string
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{
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$label = urlencode($issuer . ':' . $userEmail);
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$otpauth = "otpauth://totp/{$label}?secret={$secret}&issuer=" . urlencode($issuer);
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return "https://api.qrserver.com/v1/create-qr-code/?size=200x200&data=" . urlencode($otpauth);
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}
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}
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