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<?php
/**
* Contact form handler for danix.me
*
* Spam protection:
* 1. Honeypot field — bots fill it, humans don't see it
* 2. Timing check — reject submissions faster than MIN_ELAPSED seconds
* 3. IP rate limit — one submission per IP per RATE_WINDOW seconds
*/
ob_start();
header('Content-Type: application/json; charset=utf-8');
header('X-Content-Type-Options: nosniff');
header('X-Frame-Options: DENY');
header('Referrer-Policy: strict-origin-when-cross-origin');
header('Cache-Control: no-store');
// ── Configuration ─────────────────────────────────────────────────────────────
// Credentials are read from server environment variables — never hardcoded here.
// Set them in your nginx fastcgi_param, Apache SetEnv, or hosting panel.
const SENDER_DOMAIN = 'danix.xyz'; // used in From name and subject prefix
const ALLOWED_ORIGIN = 'https://danix.me'; // CSRF: only accept from this origin
const MIN_ELAPSED = 4; // seconds before submission is accepted
const RATE_WINDOW = 300; // seconds between allowed submissions per IP
const RATE_DIR = '/var/lib/danixme/cf_rate'; // owned by www-data:www-data, mode 0700
// $cfg = [
// 'recipient' => getenv('MAIL_RECIPIENT') ?: '',
// 'smtp_host' => getenv('MAIL_SMTP_HOST') ?: '',
// 'smtp_port' => (int)(getenv('MAIL_SMTP_PORT') ?: 587),
// 'smtp_secure' => getenv('MAIL_SMTP_SECURE') ?: 'tls',
// 'smtp_user' => getenv('MAIL_SMTP_USER') ?: '',
// 'smtp_pass' => getenv('MAIL_SMTP_PASS') ?: '',
// ];
$cfg = require dirname(__DIR__, 2) . '/mail-config.php';
if ($cfg['recipient'] === '' || $cfg['smtp_host'] === '' || $cfg['smtp_user'] === '') {
out(500, 'Mail not configured');
}
// ──────────────────────────────────────────────────────────────────────────────
// Only accept POST
if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
out(405, 'Method not allowed');
}
// ── CSRF: verify request originates from our own domain ───────────────────────
$origin = $_SERVER['HTTP_ORIGIN'] ?? '';
$referer = $_SERVER['HTTP_REFERER'] ?? '';
if ($origin !== '') {
if ($origin !== ALLOWED_ORIGIN) {
out(403, 'Forbidden');
}
} elseif (strpos($referer, ALLOWED_ORIGIN . '/') !== 0) {
out(403, 'Forbidden');
}
// ─────────────────────────────────────────────────────────────────────────────
// ── Honeypot ──────────────────────────────────────────────────────────────────
// If the hidden "website" field is filled, it's a bot — silently pretend success.
if (!empty($_POST['website'])) {
out(200, null, true);
}
// ── Timing check ──────────────────────────────────────────────────────────────
$loadedAt = (int) filter_input(INPUT_POST, '_t', FILTER_SANITIZE_NUMBER_INT);
$elapsed = time() - $loadedAt;
if ($loadedAt === 0 || $elapsed < MIN_ELAPSED || $elapsed > 7200) {
out(400, 'Invalid submission');
}
// ── Rate limiting ─────────────────────────────────────────────────────────────
$ip = preg_replace('/[^a-f0-9:.]/', '', $_SERVER['REMOTE_ADDR'] ?? '');
$lockDir = rtrim(RATE_DIR, '/');
if (!is_dir($lockDir)) {
@mkdir($lockDir, 0700, true);
}
$lockFile = $lockDir . '/' . md5($ip) . '.lock';
// Atomic check+write using exclusive lock — prevents TOCTOU race condition
$fp = fopen($lockFile, 'c+');
if ($fp === false || !flock($fp, LOCK_EX)) {
out(500, 'Server error');
}
$lastTime = (int) fread($fp, 20);
if ($lastTime > 0 && (time() - $lastTime) < RATE_WINDOW) {
flock($fp, LOCK_UN);
fclose($fp);
out(429, 'Too many requests');
}
// ── Sanitize & validate ───────────────────────────────────────────────────────
$name = clean(INPUT_POST, 'name', 100);
$email = trim(filter_input(INPUT_POST, 'email', FILTER_SANITIZE_EMAIL) ?? '');
$subject = clean(INPUT_POST, 'subject', 200);
$message = clean(INPUT_POST, 'message', 5000);
if ($name === '' || $email === '' || $message === '') {
flock($fp, LOCK_UN); fclose($fp);
out(400, 'Missing required fields');
}
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
flock($fp, LOCK_UN); fclose($fp);
out(400, 'Invalid email address');
}
// ── Build and send the email via PHPMailer ────────────────────────────────────
require __DIR__ . '/vendor/autoload.php';
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\SMTP;
use PHPMailer\PHPMailer\Exception as MailerException;
$subjectLine = '[contact from danix.me] - ' . ($subject !== '' ? $subject : 'New message from ' . $name);
$body = implode("\n", [
'Name: ' . $name,
'Email: ' . $email,
'Subject: ' . ($subject ?: '—'),
'',
str_repeat('─', 48),
'',
$message,
]);
$mail = new PHPMailer(true);
try {
$mail->isSMTP();
$mail->Host = $cfg['smtp_host'];
$mail->SMTPAuth = true;
$mail->Username = $cfg['smtp_user'];
$mail->Password = $cfg['smtp_pass'];
$mail->SMTPSecure = $cfg['smtp_secure'] === 'ssl' ? PHPMailer::ENCRYPTION_SMTPS : PHPMailer::ENCRYPTION_STARTTLS;
$mail->Port = $cfg['smtp_port'];
$mail->CharSet = 'UTF-8';
$mail->setFrom('danix@' . SENDER_DOMAIN, SENDER_DOMAIN);
$mail->addReplyTo($email, $name);
$mail->addAddress($cfg['recipient']);
$mail->Subject = $subjectLine;
$mail->Body = $body;
$mail->send();
rewind($fp);
ftruncate($fp, 0);
fwrite($fp, (string) time());
flock($fp, LOCK_UN);
fclose($fp);
out(200, null, true);
} catch (MailerException $e) {
flock($fp, LOCK_UN);
fclose($fp);
out(500, 'Failed to send email');
}
// ── Helpers ───────────────────────────────────────────────────────────────────
function clean(int $type, string $key, int $maxLen): string
{
$val = filter_input($type, $key, FILTER_UNSAFE_RAW) ?? '';
$val = strip_tags(trim((string) $val));
return mb_substr($val, 0, $maxLen);
}
function out(int $code, ?string $error, bool $success = false): void
{
ob_end_clean();
http_response_code($code);
echo json_encode(['success' => $success, 'error' => $error]);
exit;
}
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