pixelfed/app/Util/ActivityPub/HttpSignature.php
2024-08-02 01:40:06 -06:00

161 lines
5.5 KiB
PHP

<?php
namespace App\Util\ActivityPub;
use App\Models\InstanceActor;
use App\Profile;
use Cache;
use DateTime;
class HttpSignature
{
/*
* source: https://github.com/aaronpk/Nautilus/blob/master/app/ActivityPub/HTTPSignature.php
* thanks aaronpk!
*/
public static function sign(Profile $profile, $url, $body = false, $addlHeaders = [])
{
if ($body) {
$digest = self::_digest($body);
}
$user = $profile;
$headers = self::_headersToSign($url, $body ? $digest : false);
$headers = array_merge($headers, $addlHeaders);
$stringToSign = self::_headersToSigningString($headers);
$signedHeaders = implode(' ', array_map('strtolower', array_keys($headers)));
$key = openssl_pkey_get_private($user->private_key);
openssl_sign($stringToSign, $signature, $key, OPENSSL_ALGO_SHA256);
$signature = base64_encode($signature);
$signatureHeader = 'keyId="'.$user->keyId().'",headers="'.$signedHeaders.'",algorithm="rsa-sha256",signature="'.$signature.'"';
unset($headers['(request-target)']);
$headers['Signature'] = $signatureHeader;
return self::_headersToCurlArray($headers);
}
public static function instanceActorSign($url, $body = false, $addlHeaders = [], $method = 'post')
{
$keyId = config('app.url').'/i/actor#main-key';
$privateKey = Cache::rememberForever(InstanceActor::PKI_PRIVATE, function () {
return InstanceActor::first()->private_key;
});
if ($body) {
$digest = self::_digest($body);
}
$headers = self::_headersToSign($url, $body ? $digest : false, $method);
$headers = array_merge($headers, $addlHeaders);
$stringToSign = self::_headersToSigningString($headers);
$signedHeaders = implode(' ', array_map('strtolower', array_keys($headers)));
$key = openssl_pkey_get_private($privateKey);
openssl_sign($stringToSign, $signature, $key, OPENSSL_ALGO_SHA256);
$signature = base64_encode($signature);
$signatureHeader = 'keyId="'.$keyId.'",headers="'.$signedHeaders.'",algorithm="rsa-sha256",signature="'.$signature.'"';
unset($headers['(request-target)']);
$headers['Signature'] = $signatureHeader;
return $headers;
}
public static function parseSignatureHeader($signature)
{
$parts = explode(',', $signature);
$signatureData = [];
foreach ($parts as $part) {
if (preg_match('/(.+)="(.+)"/', $part, $match)) {
$signatureData[$match[1]] = $match[2];
}
}
if (! isset($signatureData['keyId'])) {
return [
'error' => 'No keyId was found in the signature header. Found: '.implode(', ', array_keys($signatureData)),
];
}
if (! filter_var($signatureData['keyId'], FILTER_VALIDATE_URL)) {
return [
'error' => 'keyId is not a URL: '.$signatureData['keyId'],
];
}
if (! Helpers::validateUrl($signatureData['keyId'])) {
return [
'error' => 'keyId is not a URL: '.$signatureData['keyId'],
];
}
if (! isset($signatureData['headers']) || ! isset($signatureData['signature'])) {
return [
'error' => 'Signature is missing headers or signature parts',
];
}
return $signatureData;
}
public static function verify($publicKey, $signatureData, $inputHeaders, $path, $body)
{
$digest = 'SHA-256='.base64_encode(hash('sha256', $body, true));
$headersToSign = [];
foreach (explode(' ', $signatureData['headers']) as $h) {
if ($h == '(request-target)') {
$headersToSign[$h] = 'post '.$path;
} elseif ($h == 'digest') {
$headersToSign[$h] = $digest;
} elseif (isset($inputHeaders[$h][0])) {
$headersToSign[$h] = $inputHeaders[$h][0];
}
}
$signingString = self::_headersToSigningString($headersToSign);
$verified = openssl_verify($signingString, base64_decode($signatureData['signature']), $publicKey, OPENSSL_ALGO_SHA256);
return [$verified, $signingString];
}
private static function _headersToSigningString($headers)
{
return implode("\n", array_map(function ($k, $v) {
return strtolower($k).': '.$v;
}, array_keys($headers), $headers));
}
private static function _headersToCurlArray($headers)
{
return array_map(function ($k, $v) {
return "$k: $v";
}, array_keys($headers), $headers);
}
private static function _digest($body)
{
if (is_array($body)) {
$body = json_encode($body);
}
return base64_encode(hash('sha256', $body, true));
}
protected static function _headersToSign($url, $digest = false, $method = 'post')
{
$date = new DateTime('UTC');
if (! in_array($method, ['post', 'get'])) {
throw new \Exception('Invalid method used to sign headers in HttpSignature');
}
$headers = [
'(request-target)' => $method.' '.parse_url($url, PHP_URL_PATH),
'Host' => parse_url($url, PHP_URL_HOST),
'Date' => $date->format('D, d M Y H:i:s \G\M\T'),
];
if ($digest) {
$headers['Digest'] = 'SHA-256='.$digest;
}
return $headers;
}
}