<?php
-
/**
- * @file src/Util/HTTPSignature.php
+ * @copyright Copyright (C) 2010-2022, the Friendica project
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ *
*/
+
namespace Friendica\Util;
-use Friendica\Core\Config;
+use Friendica\Core\Logger;
+use Friendica\Database\Database;
use Friendica\Database\DBA;
+use Friendica\DI;
+use Friendica\Model\APContact;
+use Friendica\Model\Contact;
+use Friendica\Model\User;
+use Friendica\Network\HTTPClient\Client\HttpClientOptions;
/**
- * @brief Implements HTTP Signatures per draft-cavage-http-signatures-07.
+ * Implements HTTP Signatures per draft-cavage-http-signatures-07.
*
* Ported from Hubzilla: https://framagit.org/hubzilla/core/blob/master/Zotlabs/Web/HTTPSig.php
*
+ * Other parts of the code for HTTP signing are taken from the Osada project.
+ * https://framagit.org/macgirvin/osada
+ *
* @see https://tools.ietf.org/html/draft-cavage-http-signatures-07
*/
class HTTPSignature
{
+ // See draft-cavage-http-signatures-08
/**
- * @brief RFC5843
- *
- * Disabled until Friendica's ActivityPub implementation
- * is ready.
+ * Verifies a magic request
*
- * @see https://tools.ietf.org/html/rfc5843
+ * @param $key
*
- * @param string $body The value to create the digest for
- * @param boolean $set (optional, default true)
- * If set send a Digest HTTP header
- *
- * @return string The generated digest of $body
+ * @return array with verification data
+ * @throws \Friendica\Network\HTTPException\InternalServerErrorException
*/
-// public static function generateDigest($body, $set = true)
-// {
-// $digest = base64_encode(hash('sha256', $body, true));
-//
-// if($set) {
-// header('Digest: SHA-256=' . $digest);
-// }
-// return $digest;
-// }
-
- // See draft-cavage-http-signatures-08
- public static function verify($data, $key = '')
+ public static function verifyMagic($key)
{
- $body = $data;
$headers = null;
$spoofable = false;
$result = [
'signer' => '',
'header_signed' => false,
- 'header_valid' => false,
- 'content_signed' => false,
- 'content_valid' => false
+ 'header_valid' => false
];
// Decide if $data arrived via controller submission or curl.
- if (is_array($data) && $data['header']) {
- if (!$data['success']) {
- return $result;
- }
+ $headers = [];
+ $headers['(request-target)'] = strtolower(DI::args()->getMethod()).' '.$_SERVER['REQUEST_URI'];
- $h = new HTTPHeaders($data['header']);
- $headers = $h->fetch();
- $body = $data['body'];
- } else {
- $headers = [];
- $headers['(request-target)'] = strtolower($_SERVER['REQUEST_METHOD']).' '.$_SERVER['REQUEST_URI'];
-
- foreach ($_SERVER as $k => $v) {
- if (strpos($k, 'HTTP_') === 0) {
- $field = str_replace('_', '-', strtolower(substr($k, 5)));
- $headers[$field] = $v;
- }
+ foreach ($_SERVER as $k => $v) {
+ if (strpos($k, 'HTTP_') === 0) {
+ $field = str_replace('_', '-', strtolower(substr($k, 5)));
+ $headers[$field] = $v;
}
}
$sig_block = null;
- if (array_key_exists('signature', $headers)) {
- $sig_block = self::parseSigheader($headers['signature']);
- } elseif (array_key_exists('authorization', $headers)) {
- $sig_block = self::parseSigheader($headers['authorization']);
- }
+ $sig_block = self::parseSigheader($headers['authorization']);
if (!$sig_block) {
- logger('no signature provided.');
+ Logger::notice('no signature provided.');
return $result;
}
- // Warning: This log statement includes binary data
- // logger('sig_block: ' . print_r($sig_block,true), LOGGER_DATA);
-
$result['header_signed'] = true;
$signed_headers = $sig_block['headers'];
$signed_data = rtrim($signed_data, "\n");
- $algorithm = null;
- if ($sig_block['algorithm'] === 'rsa-sha256') {
- $algorithm = 'sha256';
- }
- if ($sig_block['algorithm'] === 'rsa-sha512') {
- $algorithm = 'sha512';
- }
+ $algorithm = 'sha512';
if ($key && function_exists($key)) {
$result['signer'] = $sig_block['keyId'];
$key = $key($sig_block['keyId']);
}
- logger('Got keyID ' . $sig_block['keyId']);
-
- // We don't use Activity Pub at the moment.
-// if (!$key) {
-// $result['signer'] = $sig_block['keyId'];
-// $key = self::getActivitypubKey($sig_block['keyId']);
-// }
+ Logger::info('Got keyID ' . $sig_block['keyId']);
if (!$key) {
return $result;
$x = Crypto::rsaVerify($signed_data, $sig_block['signature'], $key, $algorithm);
- logger('verified: ' . $x, LOGGER_DEBUG);
+ Logger::info('verified: ' . $x);
if (!$x) {
return $result;
$result['header_valid'] = true;
}
- if (in_array('digest', $signed_headers)) {
- $result['content_signed'] = true;
- $digest = explode('=', $headers['digest']);
-
- if ($digest[0] === 'SHA-256') {
- $hashalg = 'sha256';
- }
- if ($digest[0] === 'SHA-512') {
- $hashalg = 'sha512';
- }
-
- // The explode operation will have stripped the '=' padding, so compare against unpadded base64.
- if (rtrim(base64_encode(hash($hashalg, $body, true)), '=') === $digest[1]) {
- $result['content_valid'] = true;
- }
- }
-
- logger('Content_Valid: ' . $result['content_valid']);
-
return $result;
}
/**
- * Fetch the public key for Activity Pub contact.
- *
- * @param string|int The identifier (contact addr or contact ID).
- * @return string|boolean The public key or false on failure.
- */
- private static function getActivitypubKey($id)
- {
- if (strpos($id, 'acct:') === 0) {
- $contact = DBA::selectFirst('contact', ['pubkey'], ['uid' => 0, 'addr' => str_replace('acct:', '', $id)]);
- } else {
- $contact = DBA::selectFirst('contact', ['pubkey'], ['id' => $id, 'network' => 'activitypub']);
- }
-
- if (DBA::isResult($contact)) {
- return $contact['pubkey'];
- }
-
- if(function_exists('as_fetch')) {
- $r = as_fetch($id);
- }
-
- if ($r) {
- $j = json_decode($r, true);
-
- if (array_key_exists('publicKey', $j) && array_key_exists('publicKeyPem', $j['publicKey'])) {
- if ((array_key_exists('id', $j['publicKey']) && $j['publicKey']['id'] !== $id) && $j['id'] !== $id) {
- return false;
- }
-
- return $j['publicKey']['publicKeyPem'];
- }
- }
-
- return false;
- }
-
- /**
- * @brief
- *
- * @param string $request
* @param array $head
* @param string $prvkey
* @param string $keyid (optional, default 'Key')
- * @param boolean $send_headers (optional, default false)
- * If set send a HTTP header
- * @param boolean $auth (optional, default false)
- * @param string $alg (optional, default 'sha256')
- * @param string $crypt_key (optional, default null)
- * @param string $crypt_algo (optional, default 'aes256ctr')
*
* @return array
*/
- public static function createSig($request, $head, $prvkey, $keyid = 'Key', $send_headers = false, $auth = false, $alg = 'sha256', $crypt_key = null, $crypt_algo = 'aes256ctr')
+ public static function createSig($head, $prvkey, $keyid = 'Key')
{
$return_headers = [];
-
- if ($alg === 'sha256') {
- $algorithm = 'rsa-sha256';
+ if (!empty($head)) {
+ $return_headers = $head;
}
- if ($alg === 'sha512') {
- $algorithm = 'rsa-sha512';
- }
+ $alg = 'sha512';
+ $algorithm = 'rsa-sha512';
- $x = self::sign($request, $head, $prvkey, $alg);
+ $x = self::sign($head, $prvkey, $alg);
$headerval = 'keyId="' . $keyid . '",algorithm="' . $algorithm
. '",headers="' . $x['headers'] . '",signature="' . $x['signature'] . '"';
- if ($crypt_key) {
- $x = Crypto::encapsulate($headerval, $crypt_key, $crypt_algo);
- $headerval = 'iv="' . $x['iv'] . '",key="' . $x['key'] . '",alg="' . $x['alg'] . '",data="' . $x['data'] . '"';
- }
-
- if ($auth) {
- $sighead = 'Authorization: Signature ' . $headerval;
- } else {
- $sighead = 'Signature: ' . $headerval;
- }
-
- if ($head) {
- foreach ($head as $k => $v) {
- if ($send_headers) {
- // This is for ActivityPub implementation.
- // Since the Activity Pub implementation isn't
- // ready at the moment, we comment it out.
- // header($k . ': ' . $v);
- } else {
- $return_headers[] = $k . ': ' . $v;
- }
- }
- }
-
- if ($send_headers) {
- // This is for ActivityPub implementation.
- // Since the Activity Pub implementation isn't
- // ready at the moment, we comment it out.
- // header($sighead);
- } else {
- $return_headers[] = $sighead;
- }
+ $return_headers['Authorization'] = ['Signature ' . $headerval];
return $return_headers;
}
/**
- * @brief
- *
- * @param string $request
* @param array $head
* @param string $prvkey
* @param string $alg (optional) default 'sha256'
*
* @return array
*/
- private static function sign($request, $head, $prvkey, $alg = 'sha256')
+ private static function sign($head, $prvkey, $alg = 'sha256')
{
$ret = [];
$headers = '';
$fields = '';
- if ($request) {
- $headers = '(request-target)' . ': ' . trim($request) . "\n";
- $fields = '(request-target)';
- }
-
- if ($head) {
- foreach ($head as $k => $v) {
- $headers .= strtolower($k) . ': ' . trim($v) . "\n";
- if ($fields) {
- $fields .= ' ';
- }
- $fields .= strtolower($k);
+ foreach ($head as $k => $v) {
+ if (is_array($v)) {
+ $v = implode(', ', $v);
+ }
+ $headers .= strtolower($k) . ': ' . trim($v) . "\n";
+ if ($fields) {
+ $fields .= ' ';
}
- // strip the trailing linefeed
- $headers = rtrim($headers, "\n");
+ $fields .= strtolower($k);
}
+ // strip the trailing linefeed
+ $headers = rtrim($headers, "\n");
$sig = base64_encode(Crypto::rsaSign($headers, $prvkey, $alg));
}
/**
- * @brief
- *
* @param string $header
- * @return array associate array with
+ * @return array associative array with
* - \e string \b keyID
+ * - \e string \b created
+ * - \e string \b expires
* - \e string \b algorithm
* - \e array \b headers
* - \e string \b signature
+ * @throws \Friendica\Network\HTTPException\InternalServerErrorException
*/
public static function parseSigheader($header)
{
- $ret = [];
+ // Remove obsolete folds
+ $header = preg_replace('/\n\s+/', ' ', $header);
+
+ $token = "[!#$%&'*+.^_`|~0-9A-Za-z-]";
+
+ $quotedString = '"(?:\\\\.|[^"\\\\])*"';
+
+ $regex = "/($token+)=($quotedString|$token+)/ism";
+
$matches = [];
+ preg_match_all($regex, $header, $matches, PREG_SET_ORDER);
+
+ $headers = [];
+ foreach ($matches as $match) {
+ $headers[$match[1]] = trim($match[2] ?: $match[3], '"');
+ }
// if the header is encrypted, decrypt with (default) site private key and continue
- if (preg_match('/iv="(.*?)"/ism', $header, $matches)) {
- $header = self::decryptSigheader($header);
+ if (!empty($headers['iv'])) {
+ $header = self::decryptSigheader($headers, DI::config()->get('system', 'prvkey'));
+ return self::parseSigheader($header);
+ }
+
+ $return = [
+ 'keyId' => $headers['keyId'] ?? '',
+ 'algorithm' => $headers['algorithm'] ?? 'rsa-sha256',
+ 'created' => $headers['created'] ?? null,
+ 'expires' => $headers['expires'] ?? null,
+ 'headers' => explode(' ', $headers['headers'] ?? ''),
+ 'signature' => base64_decode(preg_replace('/\s+/', '', $headers['signature'] ?? '')),
+ ];
+
+ if (!empty($return['signature']) && !empty($return['algorithm']) && empty($return['headers'])) {
+ $return['headers'] = ['date'];
}
- if (preg_match('/keyId="(.*?)"/ism', $header, $matches)) {
- $ret['keyId'] = $matches[1];
+ return $return;
+ }
+
+ /**
+ * @param array $headers Signature headers
+ * @param string $prvkey The site private key
+ * @return string Decrypted signature string
+ * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+ */
+ private static function decryptSigheader(array $headers, string $prvkey)
+ {
+ if (!empty($headers['iv']) && !empty($headers['key']) && !empty($headers['data'])) {
+ return Crypto::unencapsulate($headers, $prvkey);
}
- if (preg_match('/algorithm="(.*?)"/ism', $header, $matches)) {
- $ret['algorithm'] = $matches[1];
+ return '';
+ }
+
+ /*
+ * Functions for ActivityPub
+ */
+
+ /**
+ * Transmit given data to a target for a user
+ *
+ * @param array $data Data that is about to be send
+ * @param string $target The URL of the inbox
+ * @param integer $uid User id of the sender
+ *
+ * @return boolean Was the transmission successful?
+ * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+ */
+ public static function transmit($data, $target, $uid)
+ {
+ $owner = User::getOwnerDataById($uid);
+
+ if (!$owner) {
+ return;
}
- if (preg_match('/headers="(.*?)"/ism', $header, $matches)) {
- $ret['headers'] = explode(' ', $matches[1]);
+ $content = json_encode($data, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
+
+ // Header data that is about to be signed.
+ $host = parse_url($target, PHP_URL_HOST);
+ $path = parse_url($target, PHP_URL_PATH);
+ $digest = 'SHA-256=' . base64_encode(hash('sha256', $content, true));
+ $content_length = strlen($content);
+ $date = DateTimeFormat::utcNow(DateTimeFormat::HTTP);
+
+ $headers = [
+ 'Date' => $date,
+ 'Content-Length' => $content_length,
+ 'Digest' => $digest,
+ 'Host' => $host
+ ];
+
+ $signed_data = "(request-target): post " . $path . "\ndate: ". $date . "\ncontent-length: " . $content_length . "\ndigest: " . $digest . "\nhost: " . $host;
+
+ $signature = base64_encode(Crypto::rsaSign($signed_data, $owner['uprvkey'], 'sha256'));
+
+ $headers['Signature'] = 'keyId="' . $owner['url'] . '#main-key' . '",algorithm="rsa-sha256",headers="(request-target) date content-length digest host",signature="' . $signature . '"';
+
+ $headers['Content-Type'] = 'application/activity+json';
+
+ $postResult = DI::httpClient()->post($target, $content, $headers);
+ $return_code = $postResult->getReturnCode();
+
+ Logger::info('Transmit to ' . $target . ' returned ' . $return_code);
+
+ $success = ($return_code >= 200) && ($return_code <= 299);
+
+ self::setInboxStatus($target, $success);
+
+ return $success;
+ }
+
+ /**
+ * Set the delivery status for a given inbox
+ *
+ * @param string $url The URL of the inbox
+ * @param boolean $success Transmission status
+ * @param boolean $shared The inbox is a shared inbox
+ */
+ static public function setInboxStatus($url, $success, $shared = false)
+ {
+ $now = DateTimeFormat::utcNow();
+
+ $status = DBA::selectFirst('inbox-status', [], ['url' => $url]);
+ if (!DBA::isResult($status)) {
+ DBA::insert('inbox-status', ['url' => $url, 'created' => $now, 'shared' => $shared], Database::INSERT_IGNORE);
+ $status = DBA::selectFirst('inbox-status', [], ['url' => $url]);
}
- if (preg_match('/signature="(.*?)"/ism', $header, $matches)) {
- $ret['signature'] = base64_decode(preg_replace('/\s+/', '', $matches[1]));
+ if ($success) {
+ $fields = ['success' => $now];
+ } else {
+ $fields = ['failure' => $now];
}
- if (($ret['signature']) && ($ret['algorithm']) && (!$ret['headers'])) {
- $ret['headers'] = ['date'];
+ if ($status['failure'] > DBA::NULL_DATETIME) {
+ $new_previous_stamp = strtotime($status['failure']);
+ $old_previous_stamp = strtotime($status['previous']);
+
+ // Only set "previous" with at least one day difference.
+ // We use this to assure to not accidentally archive too soon.
+ if (($new_previous_stamp - $old_previous_stamp) >= 86400) {
+ $fields['previous'] = $status['failure'];
+ }
}
- return $ret;
+ if (!$success) {
+ if ($status['success'] <= DBA::NULL_DATETIME) {
+ $stamp1 = strtotime($status['created']);
+ } else {
+ $stamp1 = strtotime($status['success']);
+ }
+
+ $stamp2 = strtotime($now);
+ $previous_stamp = strtotime($status['previous']);
+
+ // Archive the inbox when there had been failures for five days.
+ // Additionally ensure that at least one previous attempt has to be in between.
+ if ((($stamp2 - $stamp1) >= 86400 * 5) && ($previous_stamp > $stamp1)) {
+ $fields['archive'] = true;
+ }
+ } else {
+ $fields['archive'] = false;
+ }
+
+ DBA::update('inbox-status', $fields, ['url' => $url]);
}
/**
- * @brief
+ * Fetches JSON data for a user
*
- * @param string $header
- * @param string $prvkey (optional), if not set use site private key
+ * @param string $request request url
+ * @param integer $uid User id of the requester
*
- * @return array|string associative array, empty string if failue
- * - \e string \b iv
- * - \e string \b key
- * - \e string \b alg
- * - \e string \b data
+ * @return array JSON array
+ * @throws \Friendica\Network\HTTPException\InternalServerErrorException
*/
- private static function decryptSigheader($header, $prvkey = null)
+ public static function fetch($request, $uid)
{
- $iv = $key = $alg = $data = null;
+ $curlResult = self::fetchRaw($request, $uid);
- if (!$prvkey) {
- $prvkey = Config::get('system', 'prvkey');
+ if (empty($curlResult)) {
+ return false;
}
- $matches = [];
+ if (!$curlResult->isSuccess() || empty($curlResult->getBody())) {
+ return false;
+ }
- if (preg_match('/iv="(.*?)"/ism', $header, $matches)) {
- $iv = $matches[1];
+ $content = json_decode($curlResult->getBody(), true);
+ if (empty($content) || !is_array($content)) {
+ return false;
}
- if (preg_match('/key="(.*?)"/ism', $header, $matches)) {
- $key = $matches[1];
+ return $content;
+ }
+
+ /**
+ * Fetches raw data for a user
+ *
+ * @param string $request request url
+ * @param integer $uid User id of the requester
+ * @param boolean $binary TRUE if asked to return binary results (file download) (default is "false")
+ * @param array $opts (optional parameters) assoziative array with:
+ * 'accept_content' => supply Accept: header with 'accept_content' as the value
+ * 'timeout' => int Timeout in seconds, default system config value or 60 seconds
+ * 'nobody' => only return the header
+ * 'cookiejar' => path to cookie jar file
+ *
+ * @return \Friendica\Network\HTTPClient\Capability\ICanHandleHttpResponses CurlResult
+ * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+ */
+ public static function fetchRaw($request, $uid = 0, $opts = ['accept_content' => ['application/activity+json, application/ld+json; profile="https://www.w3.org/ns/activitystreams"']])
+ {
+ $header = [];
+
+ if (!empty($uid)) {
+ $owner = User::getOwnerDataById($uid);
+ if (!$owner) {
+ return;
+ }
+ } else {
+ $owner = User::getSystemAccount();
+ if (!$owner) {
+ return;
+ }
}
- if (preg_match('/alg="(.*?)"/ism', $header, $matches)) {
- $alg = $matches[1];
+ if (!empty($owner['uprvkey'])) {
+ // Header data that is about to be signed.
+ $host = parse_url($request, PHP_URL_HOST);
+ $path = parse_url($request, PHP_URL_PATH);
+ $date = DateTimeFormat::utcNow(DateTimeFormat::HTTP);
+
+ $header['Date'] = $date;
+ $header['Host'] = $host;
+
+ $signed_data = "(request-target): get " . $path . "\ndate: ". $date . "\nhost: " . $host;
+
+ $signature = base64_encode(Crypto::rsaSign($signed_data, $owner['uprvkey'], 'sha256'));
+
+ $header['Signature'] = 'keyId="' . $owner['url'] . '#main-key' . '",algorithm="rsa-sha256",headers="(request-target) date host",signature="' . $signature . '"';
}
- if (preg_match('/data="(.*?)"/ism', $header, $matches)) {
- $data = $matches[1];
+ $curl_opts = $opts;
+ $curl_opts[HttpClientOptions::HEADERS] = $header;
+
+ if (!empty($opts['nobody'])) {
+ $curlResult = DI::httpClient()->head($request, $curl_opts);
+ } else {
+ $curlResult = DI::httpClient()->get($request, $curl_opts);
}
+ $return_code = $curlResult->getReturnCode();
+
+ Logger::info('Fetched for user ' . $uid . ' from ' . $request . ' returned ' . $return_code);
+
+ return $curlResult;
+ }
- if ($iv && $key && $alg && $data) {
- return Crypto::unencapsulate(['iv' => $iv, 'key' => $key, 'alg' => $alg, 'data' => $data], $prvkey);
+ /**
+ * Gets a signer from a given HTTP request
+ *
+ * @param $content
+ * @param $http_headers
+ *
+ * @return string Signer
+ * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+ */
+ public static function getSigner($content, $http_headers)
+ {
+ if (empty($http_headers['HTTP_SIGNATURE'])) {
+ Logger::debug('No HTTP_SIGNATURE header');
+ return false;
}
- return '';
+ if (!empty($content)) {
+ $object = json_decode($content, true);
+ if (empty($object)) {
+ Logger::info('No object');
+ return false;
+ }
+
+ $actor = JsonLD::fetchElement($object, 'actor', 'id');
+ } else {
+ $actor = '';
+ }
+
+ $headers = [];
+ $headers['(request-target)'] = strtolower(DI::args()->getMethod()) . ' ' . parse_url($http_headers['REQUEST_URI'], PHP_URL_PATH);
+
+ // First take every header
+ foreach ($http_headers as $k => $v) {
+ $field = str_replace('_', '-', strtolower($k));
+ $headers[$field] = $v;
+ }
+
+ // Now add every http header
+ foreach ($http_headers as $k => $v) {
+ if (strpos($k, 'HTTP_') === 0) {
+ $field = str_replace('_', '-', strtolower(substr($k, 5)));
+ $headers[$field] = $v;
+ }
+ }
+
+ $sig_block = self::parseSigHeader($http_headers['HTTP_SIGNATURE']);
+
+ // Add fields from the signature block to the header. See issue 8845
+ if (!empty($sig_block['created']) && empty($headers['(created)'])) {
+ $headers['(created)'] = $sig_block['created'];
+ }
+
+ if (!empty($sig_block['expires']) && empty($headers['(expires)'])) {
+ $headers['(expires)'] = $sig_block['expires'];
+ }
+
+ if (empty($sig_block) || empty($sig_block['headers']) || empty($sig_block['keyId'])) {
+ Logger::info('No headers or keyId');
+ return false;
+ }
+
+ $signed_data = '';
+ foreach ($sig_block['headers'] as $h) {
+ if (array_key_exists($h, $headers)) {
+ $signed_data .= $h . ': ' . $headers[$h] . "\n";
+ } else {
+ Logger::info('Requested header field not found', ['field' => $h, 'header' => $headers]);
+ }
+ }
+ $signed_data = rtrim($signed_data, "\n");
+
+ if (empty($signed_data)) {
+ Logger::info('Signed data is empty');
+ return false;
+ }
+
+ $algorithm = null;
+
+ // Wildcard value where signing algorithm should be derived from keyId
+ // @see https://tools.ietf.org/html/draft-ietf-httpbis-message-signatures-00#section-4.1
+ // Defaulting to SHA256 as it seems to be the prevalent implementation
+ // @see https://arewehs2019yet.vpzom.click
+ if ($sig_block['algorithm'] === 'hs2019') {
+ $algorithm = 'sha256';
+ }
+
+ if ($sig_block['algorithm'] === 'rsa-sha256') {
+ $algorithm = 'sha256';
+ }
+
+ if ($sig_block['algorithm'] === 'rsa-sha512') {
+ $algorithm = 'sha512';
+ }
+
+ if (empty($algorithm)) {
+ Logger::info('No alagorithm');
+ return false;
+ }
+
+ $key = self::fetchKey($sig_block['keyId'], $actor);
+ if (empty($key)) {
+ Logger::info('Empty key');
+ return false;
+ }
+
+ if (!empty($key['url']) && !empty($key['type']) && ($key['type'] == 'Tombstone')) {
+ Logger::info('Actor is a tombstone', ['key' => $key]);
+
+ if (!Contact::isLocal($key['url'])) {
+ // We now delete everything that we possibly knew from this actor
+ Contact::deleteContactByUrl($key['url']);
+ }
+ return null;
+ }
+
+ if (empty($key['pubkey'])) {
+ Logger::info('Empty pubkey');
+ return false;
+ }
+
+ if (!Crypto::rsaVerify($signed_data, $sig_block['signature'], $key['pubkey'], $algorithm)) {
+ Logger::info('Verification failed', ['signed_data' => $signed_data, 'algorithm' => $algorithm, 'header' => $sig_block['headers'], 'http_headers' => $http_headers]);
+ return false;
+ }
+
+ $hasGoodSignedContent = false;
+
+ // Check the digest when it is part of the signed data
+ if (!empty($content) && in_array('digest', $sig_block['headers'])) {
+ $digest = explode('=', $headers['digest'], 2);
+ if ($digest[0] === 'SHA-256') {
+ $hashalg = 'sha256';
+ }
+ if ($digest[0] === 'SHA-512') {
+ $hashalg = 'sha512';
+ }
+
+ /// @todo add all hashes from the rfc
+
+ if (!empty($hashalg) && base64_encode(hash($hashalg, $content, true)) != $digest[1]) {
+ Logger::info('Digest does not match');
+ return false;
+ }
+
+ $hasGoodSignedContent = true;
+ }
+
+ if (in_array('date', $sig_block['headers']) && !empty($headers['date'])) {
+ $created = strtotime($headers['date']);
+ } elseif (in_array('(created)', $sig_block['headers']) && !empty($sig_block['created'])) {
+ $created = $sig_block['created'];
+ } else {
+ $created = 0;
+ }
+
+ if (in_array('(expires)', $sig_block['headers']) && !empty($sig_block['expires'])) {
+ $expired = min($sig_block['expires'], $created + 300);
+ } else {
+ $expired = $created + 300;
+ }
+
+ // Check if the signed date field is in an acceptable range
+ if (!empty($created)) {
+ $current = time();
+
+ // Calculate with a grace period of 60 seconds to avoid slight time differences between the servers
+ if (($created - 60) > $current) {
+ Logger::notice('Signature created in the future', ['created' => date(DateTimeFormat::MYSQL, $created), 'expired' => date(DateTimeFormat::MYSQL, $expired), 'current' => date(DateTimeFormat::MYSQL, $current)]);
+ return false;
+ }
+
+ if ($current > $expired) {
+ Logger::notice('Signature expired', ['created' => date(DateTimeFormat::MYSQL, $created), 'expired' => date(DateTimeFormat::MYSQL, $expired), 'current' => date(DateTimeFormat::MYSQL, $current)]);
+ return false;
+ }
+
+ Logger::debug('Valid creation date', ['created' => date(DateTimeFormat::MYSQL, $created), 'expired' => date(DateTimeFormat::MYSQL, $expired), 'current' => date(DateTimeFormat::MYSQL, $current)]);
+ $hasGoodSignedContent = true;
+ }
+
+ // Check the content-length when it is part of the signed data
+ if (in_array('content-length', $sig_block['headers'])) {
+ if (strlen($content) != $headers['content-length']) {
+ Logger::info('Content length does not match');
+ return false;
+ }
+ }
+
+ // Ensure that the authentication had been done with some content
+ // Without this check someone could authenticate with fakeable data
+ if (!$hasGoodSignedContent) {
+ Logger::info('No good signed content');
+ return false;
+ }
+
+ return $key['url'];
+ }
+
+ /**
+ * fetches a key for a given id and actor
+ *
+ * @param $id
+ * @param $actor
+ *
+ * @return array with actor url and public key
+ * @throws \Exception
+ */
+ private static function fetchKey($id, $actor)
+ {
+ $url = (strpos($id, '#') ? substr($id, 0, strpos($id, '#')) : $id);
+
+ $profile = APContact::getByURL($url);
+ if (!empty($profile)) {
+ Logger::info('Taking key from id', ['id' => $id]);
+ return ['url' => $url, 'pubkey' => $profile['pubkey'], 'type' => $profile['type']];
+ } elseif ($url != $actor) {
+ $profile = APContact::getByURL($actor);
+ if (!empty($profile)) {
+ Logger::info('Taking key from actor', ['actor' => $actor]);
+ return ['url' => $actor, 'pubkey' => $profile['pubkey'], 'type' => $profile['type']];
+ }
+ }
+
+ Logger::notice('Key could not be fetched', ['url' => $url, 'actor' => $actor]);
+ return false;
}
}