adding mail tls tool

mail-tls-check.php

@@ -0,0 +1,613 @@
+<?php
+declare(strict_types=1);
+
+const CONNECT_TIMEOUT = 12; // seconds
+const EHLO_NAME = 'tool.medowar.de';
+
+/**
+ * Connects to a mail server, negotiates STARTTLS (or implicit TLS), and reports
+ * on the TLS handshake and the server certificate: trust chain, hostname match,
+ * validity window, issuer/subject and SANs.
+ */
+class MailTlsChecker
+{
+    /**
+     * @return array TLS/certificate report for the given host:port and protocol.
+     */
+    public function check(string $host, int $port, string $protocol): array
+    {
+        $report = [
+            'host'        => $host,
+            'port'        => $port,
+            'protocol'    => $protocol,
+            'mode'        => in_array($protocol, ['smtps', 'imaps', 'pop3s'], true) ? 'implicit' : 'starttls',
+            'connected'   => false,
+            'starttls'    => null,   // negotiation transcript lines (starttls only)
+            'tls_ok'      => false,  // handshake succeeded *and* peer verified
+            'trusted'     => false,  // chain verified against CA bundle
+            'hostname_ok' => false,  // certificate valid for the requested host
+            'errors'      => [],
+            'cert'        => null,
+            'tls_version' => null,
+            'cipher'      => null,
+        ];
+
+        // 1) Handshake with full verification to learn whether the chain is trusted.
+        $verified = $this->handshake($host, $port, $protocol, true, $vErr, $transcript);
+        $report['starttls'] = $transcript;
+        if ($verified === null) {
+            // Could not even reach the TLS stage — connection/protocol error.
+            $report['errors'][] = $vErr;
+            return $report;
+        }
+        $report['connected'] = true;
+        $report['trusted']   = ($vErr === null);
+        if ($vErr !== null) {
+            $report['errors'][] = 'Certificate chain not trusted: ' . $vErr;
+        }
+
+        // 2) Handshake again without verification so we can always inspect the cert,
+        //    even when it is self-signed, expired, or for the wrong hostname.
+        $stream = $this->handshake($host, $port, $protocol, false, $rErr, $t2);
+        if (!is_resource($stream)) {
+            if ($rErr !== null) {
+                $report['errors'][] = $rErr;
+            }
+            return $report;
+        }
+
+        $params  = stream_context_get_params($stream);
+        $meta    = stream_get_meta_data($stream);
+        $certRes = $params['options']['ssl']['peer_certificate'] ?? null;
+
+        // Negotiated protocol version / cipher (from the crypto meta, when exposed).
+        foreach (($meta['crypto'] ?? []) as $k => $v) {
+            if ($k === 'protocol') { $report['tls_version'] = $v; }
+            if ($k === 'cipher_name') { $report['cipher'] = $v; }
+        }
+
+        if ($certRes) {
+            $report['cert'] = $this->describeCert($certRes, $host, $report);
+            $report['hostname_ok'] = $report['cert']['hostname_ok'];
+        } else {
+            $report['errors'][] = 'TLS handshake completed but no peer certificate was presented.';
+        }
+
+        fclose($stream);
+
+        $report['tls_ok'] = $report['trusted']
+            && $report['hostname_ok']
+            && ($report['cert']['time_ok'] ?? false);
+
+        return $report;
+    }
+
+    /**
+     * Opens a TCP connection, runs the STARTTLS dance if required, then enables
+     * crypto. Returns the stream resource on success. On verification failure
+     * with $verify=true, returns false-y stream but populates $err. On connection
+     * failure returns null. $transcript receives the plaintext protocol lines.
+     *
+     * @return resource|false|null
+     */
+    private function handshake(string $host, int $port, string $protocol, bool $verify, ?string &$err, ?array &$transcript)
+    {
+        $err = null;
+        $transcript = [];
+
+        $ctx = stream_context_create(['ssl' => [
+            'verify_peer'       => $verify,
+            'verify_peer_name'  => $verify,
+            'allow_self_signed' => !$verify,
+            'capture_peer_cert' => true,
+            'SNI_enabled'       => true,
+            'peer_name'         => $host,
+        ]]);
+
+        // Always connect over plain TCP and drive the crypto switch ourselves.
+        // For implicit-TLS ports that simply means enabling crypto immediately,
+        // with no plaintext exchange — this keeps a single code path and gives us
+        // reliable error reporting via the OpenSSL error queue.
+        $errno = 0; $errstr = '';
+        $stream = @stream_socket_client(
+            sprintf('tcp://%s:%d', $host, $port),
+            $errno,
+            $errstr,
+            CONNECT_TIMEOUT,
+            STREAM_CLIENT_CONNECT,
+            $ctx
+        );
+
+        if (!is_resource($stream)) {
+            $err = $errstr !== '' ? "Connection failed: $errstr (errno $errno)" : 'Connection failed.';
+            return null;
+        }
+
+        stream_set_timeout($stream, CONNECT_TIMEOUT);
+
+        // STARTTLS protocols exchange a few plaintext commands before the switch.
+        if (!in_array($protocol, ['smtps', 'imaps', 'pop3s'], true)) {
+            try {
+                $this->negotiateStartTls($stream, $protocol, $transcript);
+            } catch (\RuntimeException $e) {
+                fclose($stream);
+                $err = $e->getMessage();
+                return null;
+            }
+        }
+
+        openssl_error_string(); // clear any stale queue entries
+        error_clear_last();
+        $ok = @stream_socket_enable_crypto(
+            $stream,
+            true,
+            STREAM_CRYPTO_METHOD_TLS_CLIENT
+        );
+
+        if ($ok !== true) {
+            $sslErr = $this->drainSslErrors();
+            $last = error_get_last()['message'] ?? '';
+            fclose($stream);
+            // Trim PHP's noisy function prefix and collapse multi-line OpenSSL blurb.
+            $detail = trim(preg_replace('/\s+/', ' ', str_replace('stream_socket_enable_crypto():', '', $sslErr ?: $last)));
+            if ($verify) {
+                // The handshake was reached; the certificate simply did not verify.
+                $err = $detail ?: 'Certificate verification failed.';
+                return false;
+            }
+            $err = $detail ?: 'TLS handshake failed.';
+            return null;
+        }
+
+        return $stream;
+    }
+
+    /**
+     * Speaks the protocol-specific STARTTLS handshake up to (not including) the
+     * crypto switch. Throws RuntimeException if the server refuses.
+     * @param resource $stream
+     */
+    private function negotiateStartTls($stream, string $protocol, array &$transcript): void
+    {
+        switch ($protocol) {
+            case 'smtp':   // submission, port 587
+            case 'smtp25': // MX / server-to-server, port 25
+                $this->expect($stream, '220', $transcript);
+                $this->send($stream, 'EHLO ' . EHLO_NAME, $transcript);
+                $ehlo = $this->readSmtp($stream, $transcript);
+                if (stripos($ehlo, 'STARTTLS') === false) {
+                    throw new \RuntimeException('Server did not advertise STARTTLS in its EHLO response.');
+                }
+                $this->send($stream, 'STARTTLS', $transcript);
+                $this->expect($stream, '220', $transcript);
+                break;
+
+            case 'imap':
+                $this->expect($stream, '* OK', $transcript, true);
+                $this->send($stream, 'a1 STARTTLS', $transcript);
+                $resp = $this->readLine($stream, $transcript);
+                if (stripos($resp, 'a1 OK') === false) {
+                    throw new \RuntimeException('IMAP server refused STARTTLS: ' . trim($resp));
+                }
+                break;
+
+            case 'pop3':
+                $this->expect($stream, '+OK', $transcript, true);
+                $this->send($stream, 'STLS', $transcript);
+                $resp = $this->readLine($stream, $transcript);
+                if (stripos($resp, '+OK') !== 0) {
+                    throw new \RuntimeException('POP3 server refused STLS: ' . trim($resp));
+                }
+                break;
+
+            default:
+                throw new \RuntimeException('Unsupported protocol: ' . $protocol);
+        }
+    }
+
+    /** @param resource $stream */
+    private function send($stream, string $line, array &$transcript): void
+    {
+        $transcript[] = 'C: ' . $line;
+        fwrite($stream, $line . "\r\n");
+    }
+
+    /**
+     * Reads one line and asserts it starts with $code (or contains it, when $contains).
+     * @param resource $stream
+     */
+    private function expect($stream, string $code, array &$transcript, bool $contains = false): void
+    {
+        $line = $this->readLine($stream, $transcript);
+        $hit = $contains ? (stripos($line, $code) !== false) : (strpos(ltrim($line), $code) === 0);
+        if (!$hit) {
+            throw new \RuntimeException(sprintf('Expected "%s" but got: %s', $code, trim($line)));
+        }
+    }
+
+    /**
+     * Reads a full multiline SMTP reply (lines like "250-..." until "250 ...").
+     * @param resource $stream
+     */
+    private function readSmtp($stream, array &$transcript): string
+    {
+        $all = '';
+        while (($line = $this->readLine($stream, $transcript)) !== '') {
+            $all .= $line;
+            // Continuation lines have a hyphen as the 4th character.
+            if (strlen($line) < 4 || $line[3] !== '-') {
+                break;
+            }
+        }
+        return $all;
+    }
+
+    /** @param resource $stream */
+    private function readLine($stream, array &$transcript): string
+    {
+        $line = fgets($stream, 4096);
+        if ($line === false) {
+            $meta = stream_get_meta_data($stream);
+            if (!empty($meta['timed_out'])) {
+                throw new \RuntimeException('Timed out waiting for the server to respond.');
+            }
+            throw new \RuntimeException('Connection closed by server before a reply was received.');
+        }
+        $transcript[] = 'S: ' . rtrim($line, "\r\n");
+        return $line;
+    }
+
+    /** Collects any pending messages from the OpenSSL error queue. */
+    private function drainSslErrors(): string
+    {
+        $msgs = [];
+        while ($e = openssl_error_string()) {
+            $msgs[] = $e;
+        }
+        return implode('; ', $msgs);
+    }
+
+    /**
+     * Parses the peer certificate and evaluates validity window + hostname match.
+     * @param \OpenSSLCertificate|resource $certRes
+     */
+    private function describeCert($certRes, string $host, array $report): array
+    {
+        $info = openssl_x509_parse($certRes) ?: [];
+        $now  = time();
+        $from = $info['validFrom_time_t'] ?? 0;
+        $to   = $info['validTo_time_t'] ?? 0;
+
+        $sans = [];
+        $altName = $info['extensions']['subjectAltName'] ?? '';
+        foreach (array_filter(array_map('trim', explode(',', $altName))) as $entry) {
+            if (stripos($entry, 'DNS:') === 0) {
+                $sans[] = substr($entry, 4);
+            } elseif (stripos($entry, 'IP Address:') === 0) {
+                $sans[] = substr($entry, 11);
+            } else {
+                $sans[] = $entry;
+            }
+        }
+        // Fall back to CN if there are no SANs (legacy certs).
+        $cn = $info['subject']['CN'] ?? null;
+        $names = $sans ?: ($cn !== null ? [$cn] : []);
+
+        $pem = '';
+        openssl_x509_export($certRes, $pem);
+
+        return [
+            'subject'      => $this->dn($info['subject'] ?? []),
+            'issuer'       => $this->dn($info['issuer'] ?? []),
+            'cn'           => $cn,
+            'sans'         => $sans,
+            'valid_from'   => $from,
+            'valid_to'     => $to,
+            'time_ok'      => $from && $to && $now >= $from && $now <= $to,
+            'expired'      => $to && $now > $to,
+            'not_yet'      => $from && $now < $from,
+            'days_left'    => $to ? (int) floor(($to - $now) / 86400) : null,
+            'hostname_ok'  => $this->matchesHost($host, $names),
+            'self_signed'  => ($this->dn($info['subject'] ?? []) === $this->dn($info['issuer'] ?? [])),
+            'serial'       => $info['serialNumberHex'] ?? ($info['serialNumber'] ?? ''),
+            'sig_type'     => $info['signatureTypeSN'] ?? '',
+            'fingerprint'  => openssl_x509_fingerprint($certRes, 'sha256') ?: '',
+        ];
+    }
+
+    /** @param array<string,mixed> $dn */
+    private function dn(array $dn): string
+    {
+        $parts = [];
+        foreach ($dn as $k => $v) {
+            $v = is_array($v) ? implode(' + ', $v) : $v;
+            $parts[] = "$k=$v";
+        }
+        return implode(', ', $parts);
+    }
+
+    /**
+     * RFC 6125 style match: exact or single leftmost wildcard.
+     * @param string[] $names
+     */
+    private function matchesHost(string $host, array $names): bool
+    {
+        $host = strtolower(rtrim($host, '.'));
+        foreach ($names as $name) {
+            $name = strtolower(rtrim($name, '.'));
+            if ($name === $host) {
+                return true;
+            }
+            if (str_starts_with($name, '*.')) {
+                $suffix = substr($name, 1); // ".example.com"
+                // Wildcard matches exactly one leftmost label.
+                if (str_ends_with($host, $suffix)
+                    && substr_count($host, '.') === substr_count($name, '.')) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+}
+
+/** Default port for each protocol, used when the user leaves the port blank. */
+const DEFAULT_PORTS = [
+    'smtp25' => 25,
+    'smtp'   => 587,
+    'smtps'  => 465,
+    'imap'   => 143,
+    'imaps'  => 993,
+    'pop3'   => 110,
+    'pop3s'  => 995,
+];
+
+const PROTOCOL_LABELS = [
+    'smtp25' => 'SMTP + STARTTLS — MX / server-to-server (25)',
+    'smtp'   => 'SMTP + STARTTLS — submission (587)',
+    'smtps'  => 'SMTPS — implicit TLS (465)',
+    'imap'   => 'IMAP + STARTTLS (143)',
+    'imaps'  => 'IMAPS — implicit TLS (993)',
+    'pop3'   => 'POP3 + STLS (110)',
+    'pop3s'  => 'POP3S — implicit TLS (995)',
+];
+
+$host     = trim((string) ($_GET['host'] ?? ''));
+$protocol = (string) ($_GET['protocol'] ?? 'smtp');
+$portRaw  = trim((string) ($_GET['port'] ?? ''));
+$report   = null;
+$inputError = null;
+
+if (!isset(DEFAULT_PORTS[$protocol])) {
+    $protocol = 'smtp';
+}
+$port = $portRaw !== '' ? (int) $portRaw : DEFAULT_PORTS[$protocol];
+
+if ($host !== '') {
+    // Accept a bare hostname; strip scheme/path/port if a URL was pasted.
+    $host = preg_replace('#^\w+://#', '', $host);
+    $host = explode('/', $host)[0];
+    $host = strtolower(trim($host));
+    if (str_contains($host, ':')) {
+        $host = explode(':', $host)[0];
+    }
+
+    if (!preg_match('/^(?=.{1,253}$)([a-z0-9](-?[a-z0-9])*\.)+[a-z]{2,}$/', $host)) {
+        $inputError = 'Please enter a valid mail server hostname (e.g. mail.example.com).';
+    } elseif ($port < 1 || $port > 65535) {
+        $inputError = 'Please enter a valid port between 1 and 65535.';
+    } else {
+        $report = (new MailTlsChecker())->check($host, $port, $protocol);
+    }
+}
+
+function fmtDate(?int $ts): string
+{
+    return $ts ? gmdate('Y-m-d H:i:s', $ts) . ' UTC' : '—';
+}
+?>
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Mail TLS Checker</title>
+    <style>
+        body {
+            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
+            max-width: 1000px;
+            margin: 40px auto;
+            padding: 0 20px;
+            background: #f5f5f5;
+            color: #333;
+        }
+        h1 { color: #333; }
+        .info { background: #e3f2fd; padding: 15px; border-radius: 5px; margin-bottom: 20px; }
+        form.lookup { margin-bottom: 20px; display: flex; gap: 10px; flex-wrap: wrap; align-items: stretch; }
+        input[type=text], select {
+            padding: 10px; font-size: 15px; border: 1px solid #ccc; border-radius: 5px; background: white;
+        }
+        input[name=host] { flex: 1; min-width: 220px; }
+        input[name=port] { width: 90px; }
+        .btn {
+            display: inline-block; padding: 10px 20px; background: #2196F3; color: white;
+            text-decoration: none; border-radius: 5px; border: none; cursor: pointer; font-size: 15px;
+        }
+        .btn:hover { background: #1976D2; }
+        .error { background: #ffebee; color: #c62828; padding: 10px; border-radius: 5px; margin: 10px 0; }
+        .verdict {
+            display: flex; align-items: center; gap: 12px; padding: 16px 20px; border-radius: 6px;
+            font-size: 18px; font-weight: 600; margin: 16px 0;
+        }
+        .verdict.ok   { background: #e8f5e9; color: #2e7d32; border-left: 6px solid #43a047; }
+        .verdict.fail { background: #ffebee; color: #c62828; border-left: 6px solid #e53935; }
+        .checks { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 10px; margin: 16px 0; }
+        .check {
+            display: flex; align-items: center; gap: 8px; padding: 12px 14px; border-radius: 5px;
+            background: white; box-shadow: 0 1px 3px rgba(0,0,0,0.1); font-size: 14px;
+        }
+        .check .ic { font-size: 18px; }
+        .check.pass { border-left: 4px solid #43a047; }
+        .check.warn { border-left: 4px solid #fb8c00; }
+        .check.crit { border-left: 4px solid #e53935; }
+        .errlist { margin: 10px 0; }
+        .errlist .error { margin: 6px 0; }
+        h2 { color: #333; margin-top: 30px; }
+        table { width: 100%; border-collapse: collapse; background: white; box-shadow: 0 1px 3px rgba(0,0,0,0.1); margin-top: 10px; }
+        th, td { padding: 10px 12px; text-align: left; border-bottom: 1px solid #eee; font-size: 13px; vertical-align: top; }
+        th { width: 180px; color: #555; background: #fafafa; font-weight: 600; }
+        td.mono, .mono { font-family: monospace; word-break: break-all; }
+        ul.sans { margin: 0; padding-left: 18px; }
+        ul.sans li { font-family: monospace; font-size: 13px; }
+        .pill { display: inline-block; padding: 2px 8px; border-radius: 10px; font-size: 12px; font-weight: 600; }
+        .pill.g { background: #e8f5e9; color: #2e7d32; }
+        .pill.r { background: #ffebee; color: #c62828; }
+        .pill.o { background: #fff3e0; color: #e65100; }
+        details.transcript { margin-top: 20px; }
+        details.transcript pre {
+            background: #263238; color: #cfd8dc; padding: 12px 14px; border-radius: 5px;
+            font-size: 12px; overflow-x: auto; line-height: 1.5;
+        }
+        summary { cursor: pointer; font-weight: 600; color: #1976D2; }
+    </style>
+</head>
+<body>
+    <h1>🔐 Mail TLS Checker</h1>
+
+    <div class="info">
+        Connects to a mail server, negotiates <strong>STARTTLS</strong> (or implicit TLS) and reports on the
+        <strong>TLS handshake</strong> and <strong>server certificate</strong>: trust chain, hostname match,
+        validity window, issuer and SANs. Nothing is sent beyond the TLS negotiation — no login, no mail.
+    </div>
+
+    <form class="lookup" method="GET">
+        <input type="text" name="host" placeholder="mail.example.com"
+               value="<?= htmlspecialchars($host) ?>" autofocus>
+        <select name="protocol">
+            <?php foreach (PROTOCOL_LABELS as $key => $label): ?>
+                <option value="<?= $key ?>" <?= $protocol === $key ? 'selected' : '' ?>>
+                    <?= htmlspecialchars($label) ?>
+                </option>
+            <?php endforeach; ?>
+        </select>
+        <input type="text" name="port" placeholder="port"
+               value="<?= htmlspecialchars($portRaw) ?>">
+        <button type="submit" class="btn">🔍 Test TLS</button>
+    </form>
+    <p style="color:#888;font-size:12px;margin-top:-10px;">
+        Leave the port blank to use the protocol default
+        (<?= implode(', ', array_map(fn($p, $n) => "$p=$n", array_keys(DEFAULT_PORTS), DEFAULT_PORTS)) ?>).
+    </p>
+
+    <?php if ($inputError): ?>
+        <div class="error"><?= htmlspecialchars($inputError) ?></div>
+    <?php endif; ?>
+
+    <?php if ($report !== null): ?>
+        <?php $cert = $report['cert']; ?>
+
+        <?php if ($report['tls_ok']): ?>
+            <div class="verdict ok">✅ TLS is valid — trusted chain, correct hostname and within its validity period.</div>
+        <?php else: ?>
+            <div class="verdict fail">❌ TLS check failed — see the details below.</div>
+        <?php endif; ?>
+
+        <?php if (!empty($report['errors'])): ?>
+            <div class="errlist">
+                <?php foreach ($report['errors'] as $e): ?>
+                    <div class="error">⚠️ <?= htmlspecialchars($e) ?></div>
+                <?php endforeach; ?>
+            </div>
+        <?php endif; ?>
+
+        <?php if ($report['connected']): ?>
+        <div class="checks">
+            <?php
+            $timeOk = $cert['time_ok'] ?? false;
+            $renderCheck = function (bool $pass, string $label, string $detail, bool $criticalIfFail = true) {
+                $cls = $pass ? 'pass' : ($criticalIfFail ? 'crit' : 'warn');
+                $ic  = $pass ? '✔️' : ($criticalIfFail ? '❌' : '⚠️');
+                printf(
+                    '<div class="check %s"><span class="ic">%s</span><div><strong>%s</strong><br>%s</div></div>',
+                    $cls, $ic, htmlspecialchars($label), htmlspecialchars($detail)
+                );
+            };
+            $renderCheck($report['trusted'], 'Trusted chain',
+                $report['trusted'] ? 'Verified against system CA bundle' : 'Not verifiable / self-signed');
+            $renderCheck($report['hostname_ok'], 'Hostname match',
+                $report['hostname_ok'] ? $report['host'] . ' is covered' : 'Certificate not valid for ' . $report['host']);
+            $renderCheck((bool) $timeOk, 'Validity period',
+                $timeOk
+                    ? ($cert['days_left'] !== null ? $cert['days_left'] . ' day(s) until expiry' : 'Currently valid')
+                    : (($cert['expired'] ?? false) ? 'Certificate has expired' : 'Certificate not yet valid'));
+            if ($cert && ($cert['days_left'] ?? null) !== null && $cert['days_left'] >= 0 && $cert['days_left'] <= 21) {
+                $renderCheck(false, 'Expiry warning', 'Expires in ' . $cert['days_left'] . ' day(s)', false);
+            }
+            ?>
+        </div>
+        <?php endif; ?>
+
+        <h2>Connection</h2>
+        <table>
+            <tr><th>Server</th><td class="mono"><?= htmlspecialchars($report['host'] . ':' . $report['port']) ?></td></tr>
+            <tr><th>Protocol</th><td><?= htmlspecialchars(PROTOCOL_LABELS[$report['protocol']] ?? $report['protocol']) ?> — <?= htmlspecialchars($report['mode']) ?></td></tr>
+            <tr><th>TLS version</th><td class="mono"><?= htmlspecialchars($report['tls_version'] ?: '—') ?></td></tr>
+            <tr><th>Cipher</th><td class="mono"><?= htmlspecialchars($report['cipher'] ?: '—') ?></td></tr>
+        </table>
+
+        <?php if ($cert): ?>
+        <h2>Certificate</h2>
+        <table>
+            <tr><th>Subject</th><td class="mono"><?= htmlspecialchars($cert['subject']) ?></td></tr>
+            <tr><th>Common name</th><td class="mono"><?= htmlspecialchars($cert['cn'] ?? '—') ?></td></tr>
+            <tr><th>Issuer</th><td class="mono"><?= htmlspecialchars($cert['issuer']) ?></td></tr>
+            <tr>
+                <th>Self-signed</th>
+                <td><?= $cert['self_signed']
+                    ? '<span class="pill o">yes</span>'
+                    : '<span class="pill g">no</span>' ?></td>
+            </tr>
+            <tr>
+                <th>Valid from</th>
+                <td class="mono"><?= htmlspecialchars(fmtDate($cert['valid_from'])) ?>
+                    <?= ($cert['not_yet'] ?? false) ? ' <span class="pill r">not yet valid</span>' : '' ?></td>
+            </tr>
+            <tr>
+                <th>Valid to</th>
+                <td class="mono"><?= htmlspecialchars(fmtDate($cert['valid_to'])) ?>
+                    <?php if ($cert['expired'] ?? false): ?>
+                        <span class="pill r">expired</span>
+                    <?php elseif (($cert['days_left'] ?? 99) <= 21): ?>
+                        <span class="pill o"><?= (int) $cert['days_left'] ?> day(s) left</span>
+                    <?php else: ?>
+                        <span class="pill g"><?= (int) $cert['days_left'] ?> day(s) left</span>
+                    <?php endif; ?>
+                </td>
+            </tr>
+            <tr>
+                <th>Subject Alt Names</th>
+                <td>
+                    <?php if (!empty($cert['sans'])): ?>
+                        <ul class="sans">
+                            <?php foreach ($cert['sans'] as $s): ?>
+                                <li><?= htmlspecialchars($s) ?></li>
+                            <?php endforeach; ?>
+                        </ul>
+                    <?php else: ?>—<?php endif; ?>
+                </td>
+            </tr>
+            <tr><th>Signature</th><td class="mono"><?= htmlspecialchars($cert['sig_type'] ?: '—') ?></td></tr>
+            <tr><th>Serial</th><td class="mono"><?= htmlspecialchars((string) $cert['serial']) ?></td></tr>
+            <tr><th>SHA-256 fingerprint</th><td class="mono"><?= htmlspecialchars(trim(chunk_split($cert['fingerprint'], 2, ':'), ':')) ?></td></tr>
+        </table>
+        <?php endif; ?>
+
+        <?php if (!empty($report['starttls'])): ?>
+        <details class="transcript">
+            <summary>STARTTLS negotiation transcript</summary>
+            <pre><?= htmlspecialchars(implode("\n", $report['starttls'])) ?></pre>
+        </details>
+        <?php endif; ?>
+    <?php endif; ?>
+</body>
+</html>