Friendica Communications Platform (please note that this is a clone of the repository at github, issues are handled there) https://friendi.ca
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<?php
/**
* @copyright Copyright (C) 2010-2021, 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\Logger;
use Friendica\Database\Database;
use Friendica\Database\DBA;
use Friendica\DI;
use Friendica\Model\APContact;
use Friendica\Model\Contact;
use Friendica\Model\User;
/**
* 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
/**
* Verifies a magic request
*
* @param $key
*
* @return array with verification data
* @throws \Friendica\Network\HTTPException\InternalServerErrorException
*/
public static function verifyMagic($key)
{
$headers = null;
$spoofable = false;
$result = [
'signer' => '',
'header_signed' => false,
'header_valid' => false
];
// Decide if $data arrived via controller submission or curl.
$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;
}
}
$sig_block = null;
$sig_block = self::parseSigheader($headers['authorization']);
if (!$sig_block) {
Logger::log('no signature provided.');
return $result;
}
$result['header_signed'] = true;
$signed_headers = $sig_block['headers'];
if (!$signed_headers) {
$signed_headers = ['date'];
}
$signed_data = '';
foreach ($signed_headers as $h) {
if (array_key_exists($h, $headers)) {
$signed_data .= $h . ': ' . $headers[$h] . "\n";
}
if (strpos($h, '.')) {
$spoofable = true;
}
}
$signed_data = rtrim($signed_data, "\n");
$algorithm = 'sha512';
if ($key && function_exists($key)) {
$result['signer'] = $sig_block['keyId'];
$key = $key($sig_block['keyId']);
}
Logger::log('Got keyID ' . $sig_block['keyId'], Logger::DEBUG);
if (!$key) {
return $result;
}
$x = Crypto::rsaVerify($signed_data, $sig_block['signature'], $key, $algorithm);
Logger::log('verified: ' . $x, Logger::DEBUG);
if (!$x) {
return $result;
}
if (!$spoofable) {
$result['header_valid'] = true;
}
return $result;
}
/**
* @param array $head
* @param string $prvkey
* @param string $keyid (optional, default 'Key')
*
* @return array
*/
public static function createSig($head, $prvkey, $keyid = 'Key')
{
$return_headers = [];
$alg = 'sha512';
$algorithm = 'rsa-sha512';
$x = self::sign($head, $prvkey, $alg);
$headerval = 'keyId="' . $keyid . '",algorithm="' . $algorithm
. '",headers="' . $x['headers'] . '",signature="' . $x['signature'] . '"';
$sighead = 'Authorization: Signature ' . $headerval;
if ($head) {
foreach ($head as $k => $v) {
$return_headers[] = $k . ': ' . $v;
}
}
$return_headers[] = $sighead;
return $return_headers;
}
/**
* @param array $head
* @param string $prvkey
* @param string $alg (optional) default 'sha256'
*
* @return array
*/
private static function sign($head, $prvkey, $alg = 'sha256')
{
$ret = [];
$headers = '';
$fields = '';
foreach ($head as $k => $v) {
$headers .= strtolower($k) . ': ' . trim($v) . "\n";
if ($fields) {
$fields .= ' ';
}
$fields .= strtolower($k);
}
// strip the trailing linefeed
$headers = rtrim($headers, "\n");
$sig = base64_encode(Crypto::rsaSign($headers, $prvkey, $alg));
$ret['headers'] = $fields;
$ret['signature'] = $sig;
return $ret;
}
/**
* @param string $header
* @return array associative array with
* - \e string \b keyID
* - \e string \b created
* - \e string \b expires
* - \e string \b algorithm
* - \e array \b headers
* - \e string \b signature
* @throws \Friendica\Network\HTTPException\InternalServerErrorException
*/
public static function parseSigheader($header)
{
// 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] ?: $match[3], '"');
}
// if the header is encrypted, decrypt with (default) site private key and continue
if (!empty($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'];
}
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);
}
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;
}
$content = json_encode($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';
$postResult = DI::httpRequest()->post($target, $content, $headers);
$return_code = $postResult->getReturnCode();
Logger::log('Transmit to ' . $target . ' returned ' . $return_code, Logger::DEBUG);
$success = ($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' => $url]);
}
if ($success) {
$fields = ['success' => $now];
} else {
$fields = ['failure' => $now];
}
if ($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'] = $status['failure'];
}
}
if (!$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]);
}
/**
* Fetches JSON data for a user
*
* @param string $request request url
* @param integer $uid User id of the requester
*
* @return array JSON array
* @throws \Friendica\Network\HTTPException\InternalServerErrorException
*/
public static function fetch($request, $uid)
{
$curlResult = self::fetchRaw($request, $uid);
if (empty($curlResult)) {
return false;
}
if (!$curlResult->isSuccess() || empty($curlResult->getBody())) {
return false;
}
$content = json_decode($curlResult->getBody(), true);
if (empty($content) || !is_array($content)) {
return false;
}
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 $opts (optional parameters) assoziative array with:
* 'accept_content' => supply Accept: header with 'accept_content' as the value
* 'timeout' => int Timeout in seconds, default system config value or 60 seconds
* 'nobody' => only return the header
* 'cookiejar' => path to cookie jar file
*
* @return object CurlResult
* @throws \Friendica\Network\HTTPException\InternalServerErrorException
*/
public static function fetchRaw($request, $uid = 0, $opts = ['accept_content' => 'application/activity+json, application/ld+json'])
{
$header = [];
if (!empty($uid)) {
$owner = User::getOwnerDataById($uid);
if (!$owner) {
return;
}
} else {
$owner = User::getSystemAccount();
if (!$owner) {
return;
}
}
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, '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="' . $signature . '"';
}
if (!empty($opts['accept_content'])) {
$header[] = 'Accept: ' . $opts['accept_content'];
}
$curl_opts = $opts;
$curl_opts['header'] = $header;
if (!empty($opts['nobody'])) {
$curlResult = DI::httpRequest()->head($request, $curl_opts);
} else {
$curlResult = DI::httpRequest()->get($request, $curl_opts);
}
$return_code = $curlResult->getReturnCode();
Logger::log('Fetched for user ' . $uid . ' from ' . $request . ' returned ' . $return_code, Logger::DEBUG);
return $curlResult;
}
/**
* 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::info('No HTTP_SIGNATURE header');
return false;
}
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 = [];
$headers['(request-target)'] = strtolower($http_headers['REQUEST_METHOD']) . ' ' . 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']);
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";
}
}
$signed_data = rtrim($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' => $key]);
// We now delete everything that we possibly knew from this actor
Contact::deleteContactByUrl($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');
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;
}
// Check if the signed date field is in an acceptable range
if (in_array('date', $sig_block['headers'])) {
$diff = abs(strtotime($headers['date']) - time());
if ($diff > 300) {
Logger::log("Header date '" . $headers['date'] . "' is with " . $diff . " seconds out of the 300 second frame. The signature is invalid.");
return false;
}
$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::log('Taking key from id ' . $id, Logger::DEBUG);
return ['url' => $url, 'pubkey' => $profile['pubkey'], 'type' => $profile['type']];
} elseif ($url != $actor) {
$profile = APContact::getByURL($actor);
if (!empty($profile)) {
Logger::log('Taking key from actor ' . $actor, Logger::DEBUG);
return ['url' => $actor, 'pubkey' => $profile['pubkey'], 'type' => $profile['type']];
}
}
return false;
}
}