Files
mood-tracking/src/Support/WebPushService.php
T

329 lines
11 KiB
PHP

<?php
declare(strict_types=1);
final class WebPushService
{
private NotificationRepository $notifications;
public function __construct(NotificationRepository $notifications)
{
$this->notifications = $notifications;
}
public function isAvailable(): bool
{
return function_exists('openssl_pkey_new')
&& function_exists('openssl_sign')
&& function_exists('openssl_encrypt')
&& function_exists('openssl_pkey_derive')
&& function_exists('curl_init');
}
public function publicKey(): ?string
{
$keys = $this->keys();
return $keys['public'] ?? null;
}
public function cronToken(): string
{
return (string) ($this->notifications->systemConfig()['cron_token'] ?? '');
}
public function send(array $subscription, array $message): array
{
if (!$this->isAvailable()) {
throw new RuntimeException('Web Push ist auf diesem Server aktuell nicht verfügbar.');
}
$endpoint = trim((string) ($subscription['endpoint'] ?? ''));
$p256dh = trim((string) ($subscription['keys']['p256dh'] ?? ''));
$auth = trim((string) ($subscription['keys']['auth'] ?? ''));
if ($endpoint === '' || $p256dh === '' || $auth === '') {
throw new RuntimeException('Die Push-Subscription ist unvollständig.');
}
$payload = json_encode([
'title' => (string) ($message['title'] ?? 'Mood-Board'),
'body' => (string) ($message['body'] ?? 'Zeit für deinen Eintrag.'),
'icon' => '/assets/branding/logo-mark.svg',
'badge' => '/assets/branding/favicon.svg',
'url' => (string) ($message['url'] ?? '/track'),
'tag' => (string) ($message['tag'] ?? 'mood-reminder'),
], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
if (!is_string($payload)) {
throw new RuntimeException('Die Push-Nachricht konnte nicht kodiert werden.');
}
$encrypted = $this->encrypt($payload, $p256dh, $auth);
$audience = $this->audienceForEndpoint($endpoint);
$authorization = $this->authorizationHeader($audience);
$headers = [
'TTL: 3600',
'Urgency: normal',
'Content-Encoding: aes128gcm',
'Content-Type: application/octet-stream',
'Authorization: ' . $authorization['header'],
'Crypto-Key: p256ecdsa=' . $authorization['public'],
];
$handle = curl_init($endpoint);
if ($handle === false) {
throw new RuntimeException('Die Verbindung zum Push-Endpunkt konnte nicht vorbereitet werden.');
}
curl_setopt_array($handle, [
CURLOPT_POST => true,
CURLOPT_POSTFIELDS => $encrypted['body'],
CURLOPT_HTTPHEADER => $headers,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_HEADER => false,
CURLOPT_TIMEOUT => 12,
]);
$responseBody = curl_exec($handle);
$status = (int) curl_getinfo($handle, CURLINFO_RESPONSE_CODE);
$error = curl_error($handle);
curl_close($handle);
return [
'ok' => $status >= 200 && $status < 300,
'status' => $status,
'remove' => in_array($status, [404, 410], true),
'error' => $error !== '' ? $error : null,
'response' => is_string($responseBody) ? $responseBody : null,
];
}
private function keys(): array
{
$config = $this->notifications->systemConfig();
$public = trim((string) ($config['vapid_public_key'] ?? ''));
$private = trim((string) ($config['vapid_private_key'] ?? ''));
if ($public !== '' && $private !== '') {
return ['public' => $public, 'private' => $private];
}
if (!$this->isAvailable()) {
return ['public' => null, 'private' => null];
}
$resource = openssl_pkey_new([
'private_key_type' => OPENSSL_KEYTYPE_EC,
'curve_name' => 'prime256v1',
]);
if ($resource === false) {
throw new RuntimeException('Die VAPID-Schlüssel konnten nicht erzeugt werden.');
}
$details = openssl_pkey_get_details($resource);
if (!is_array($details) || !isset($details['ec']['x'], $details['ec']['y'], $details['ec']['d'])) {
throw new RuntimeException('Die VAPID-Schlüsseldetails konnten nicht gelesen werden.');
}
$publicKey = "\x04" . $details['ec']['x'] . $details['ec']['y'];
$privateKey = $details['ec']['d'];
$encodedPublic = base64url_encode($publicKey);
$encodedPrivate = base64url_encode($privateKey);
$this->notifications->saveVapidKeys($encodedPublic, $encodedPrivate);
return ['public' => $encodedPublic, 'private' => $encodedPrivate];
}
private function encrypt(string $payload, string $userPublicKey, string $authSecret): array
{
$salt = random_bytes(16);
$userPublicRaw = base64url_decode($userPublicKey);
$authRaw = base64url_decode($authSecret);
$localKey = openssl_pkey_new([
'private_key_type' => OPENSSL_KEYTYPE_EC,
'curve_name' => 'prime256v1',
]);
if ($localKey === false) {
throw new RuntimeException('Der temporäre Push-Schlüssel konnte nicht erzeugt werden.');
}
$localDetails = openssl_pkey_get_details($localKey);
if (!is_array($localDetails) || !isset($localDetails['ec']['x'], $localDetails['ec']['y'])) {
throw new RuntimeException('Die temporären Push-Schlüsseldetails fehlen.');
}
$localPublicRaw = "\x04" . $localDetails['ec']['x'] . $localDetails['ec']['y'];
$userPem = $this->publicKeyPemFromRaw($userPublicRaw);
$sharedSecret = openssl_pkey_derive($userPem, $localKey, 32);
if (!is_string($sharedSecret) || $sharedSecret === '') {
throw new RuntimeException('Das gemeinsame Push-Geheimnis konnte nicht abgeleitet werden.');
}
$context = "WebPush: info\0" . $userPublicRaw . $localPublicRaw;
$keyMaterial = $this->hkdfExpand(
$this->hkdfExtract($authRaw, $sharedSecret),
$context,
32
);
$contentPrk = $this->hkdfExtract($salt, $keyMaterial);
$contentKey = $this->hkdfExpand($contentPrk, "Content-Encoding: aes128gcm\0", 16);
$nonce = $this->hkdfExpand($contentPrk, "Content-Encoding: nonce\0", 12);
$recordSize = 4096;
$plaintext = $payload . "\x02";
$tag = '';
$ciphertext = openssl_encrypt($plaintext, 'aes-128-gcm', $contentKey, OPENSSL_RAW_DATA, $nonce, $tag);
if (!is_string($ciphertext)) {
throw new RuntimeException('Die Push-Nachricht konnte nicht verschlüsselt werden.');
}
$body = $salt
. pack('N', $recordSize)
. chr(strlen($localPublicRaw))
. $localPublicRaw
. $ciphertext
. $tag;
return [
'body' => $body,
'local_public' => $localPublicRaw,
];
}
private function authorizationHeader(string $audience): array
{
$keys = $this->keys();
$header = base64url_encode((string) json_encode([
'typ' => 'JWT',
'alg' => 'ES256',
], JSON_UNESCAPED_SLASHES));
$payload = base64url_encode((string) json_encode([
'aud' => $audience,
'exp' => time() + 3600,
'sub' => (string) ($this->notifications->systemConfig()['subject'] ?? 'mailto:hello@localhost'),
], JSON_UNESCAPED_SLASHES));
$signingInput = $header . '.' . $payload;
$signatureDer = '';
$privatePem = $this->privateKeyPemFromRaw(base64url_decode((string) $keys['private']));
if (!openssl_sign($signingInput, $signatureDer, $privatePem, OPENSSL_ALGO_SHA256)) {
throw new RuntimeException('Die VAPID-Signatur konnte nicht erstellt werden.');
}
$jwt = $signingInput . '.' . base64url_encode($this->derSignatureToJose($signatureDer, 64));
return [
'header' => 'vapid t=' . $jwt . ', k=' . $keys['public'],
'public' => (string) $keys['public'],
];
}
private function audienceForEndpoint(string $endpoint): string
{
$parts = parse_url($endpoint);
if (!is_array($parts) || empty($parts['scheme']) || empty($parts['host'])) {
throw new RuntimeException('Der Push-Endpunkt ist ungültig.');
}
return $parts['scheme'] . '://' . $parts['host'];
}
private function hkdfExtract(string $salt, string $ikm): string
{
return hash_hmac('sha256', $ikm, $salt, true);
}
private function hkdfExpand(string $prk, string $info, int $length): string
{
$output = '';
$block = '';
$counter = 1;
while (strlen($output) < $length) {
$block = hash_hmac('sha256', $block . $info . chr($counter), $prk, true);
$output .= $block;
$counter++;
}
return substr($output, 0, $length);
}
private function publicKeyPemFromRaw(string $raw): string
{
$der = hex2bin('3059301306072A8648CE3D020106082A8648CE3D030107034200') . $raw;
return "-----BEGIN PUBLIC KEY-----\n"
. chunk_split(base64_encode((string) $der), 64, "\n")
. "-----END PUBLIC KEY-----\n";
}
private function privateKeyPemFromRaw(string $raw): string
{
$der = hex2bin('30770201010420')
. $raw
. hex2bin('A00A06082A8648CE3D030107A14403420004')
. substr(base64url_decode((string) $this->keys()['public']), 1);
return "-----BEGIN EC PRIVATE KEY-----\n"
. chunk_split(base64_encode((string) $der), 64, "\n")
. "-----END EC PRIVATE KEY-----\n";
}
private function derSignatureToJose(string $der, int $partLength): string
{
$offset = 0;
if (ord($der[$offset]) !== 0x30) {
throw new RuntimeException('Ungültige DER-Signatur.');
}
$offset++;
$this->readAsnLength($der, $offset);
if (ord($der[$offset]) !== 0x02) {
throw new RuntimeException('Ungültiger DER-R-Teil.');
}
$offset++;
$rLength = $this->readAsnLength($der, $offset);
$r = substr($der, $offset, $rLength);
$offset += $rLength;
if (ord($der[$offset]) !== 0x02) {
throw new RuntimeException('Ungültiger DER-S-Teil.');
}
$offset++;
$sLength = $this->readAsnLength($der, $offset);
$s = substr($der, $offset, $sLength);
return str_pad(ltrim($r, "\x00"), $partLength / 2, "\x00", STR_PAD_LEFT)
. str_pad(ltrim($s, "\x00"), $partLength / 2, "\x00", STR_PAD_LEFT);
}
private function readAsnLength(string $der, int &$offset): int
{
$length = ord($der[$offset]);
$offset++;
if (($length & 0x80) === 0) {
return $length;
}
$numberOfBytes = $length & 0x7F;
$length = 0;
for ($index = 0; $index < $numberOfBytes; $index++) {
$length = ($length << 8) | ord($der[$offset]);
$offset++;
}
return $length;
}
}