<?php namespace Zotlabs\Web; use Zotlabs\Lib\ActivityStreams; use Zotlabs\Lib\Webfinger; use Zotlabs\Web\HTTPHeaders; use Zotlabs\Lib\Libzot; /** * @brief Implements HTTP Signatures per draft-cavage-http-signatures-10. * * @see https://tools.ietf.org/html/draft-cavage-http-signatures-10 */ class HTTPSig { /** * @brief RFC5843 * * @see https://tools.ietf.org/html/rfc5843 * * @param string $body The value to create the digest for * @param string $alg hash algorithm (one of 'sha256','sha512') * @return string The generated digest header string for $body */ static function generate_digest_header($body,$alg = 'sha256') { $digest = base64_encode(hash($alg, $body, true)); switch($alg) { case 'sha512': return 'SHA-512=' . $digest; case 'sha256': default: return 'SHA-256=' . $digest; break; } } static function find_headers($data,&$body) { // decide if $data arrived via controller submission or curl if(is_array($data) && $data['header']) { if(! $data['success']) return []; $h = new HTTPHeaders($data['header']); $headers = $h->fetcharr(); $body = $data['body']; $headers['(request-target)'] = $data['request_target']; } else { $headers = []; $headers['(request-target)'] = strtolower($_SERVER['REQUEST_METHOD']) . ' ' . $_SERVER['REQUEST_URI']; $headers['content-type'] = $_SERVER['CONTENT_TYPE']; $headers['content-length'] = $_SERVER['CONTENT_LENGTH']; foreach($_SERVER as $k => $v) { if(strpos($k,'HTTP_') === 0) { $field = str_replace('_','-',strtolower(substr($k,5))); $headers[$field] = $v; } } } //logger('SERVER: ' . print_r($_SERVER,true), LOGGER_ALL); //logger('headers: ' . print_r($headers,true), LOGGER_ALL); return $headers; } // See draft-cavage-http-signatures-10 static function verify($data,$key = '', $keytype = '') { $body = $data; $headers = null; $result = [ 'signer' => '', 'portable_id' => '', 'header_signed' => false, 'header_valid' => false, 'content_signed' => false, 'content_valid' => false ]; $headers = self::find_headers($data,$body); if(! $headers) return $result; $sig_block = null; if(array_key_exists('signature',$headers)) { $sig_block = self::parse_sigheader($headers['signature']); } elseif(array_key_exists('authorization',$headers)) { $sig_block = self::parse_sigheader($headers['authorization']); } if(! $sig_block) { logger('no signature provided.', LOGGER_DEBUG); 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']; 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($h === 'date') { $d = new \DateTime($headers[$h]); $d->setTimeZone(new \DateTimeZone('UTC')); $dplus = datetime_convert('UTC','UTC','now + 1 day'); $dminus = datetime_convert('UTC','UTC','now - 1 day'); $c = $d->format('Y-m-d H:i:s'); if($c > $dplus || $c < $dminus) { logger('bad time: ' . $c); return $result; } } } $signed_data = rtrim($signed_data,"\n"); $algorithm = null; if($sig_block['algorithm'] === 'rsa-sha256') { $algorithm = 'sha256'; } if($sig_block['algorithm'] === 'rsa-sha512') { $algorithm = 'sha512'; } if(! array_key_exists('keyId',$sig_block)) return $result; $result['signer'] = $sig_block['keyId']; $cached_key = self::get_key($key,$keytype,$result['signer']); if(! ($cached_key && $cached_key['public_key'])) { return $result; } $x = rsa_verify($signed_data,$sig_block['signature'],$cached_key['public_key'],$algorithm); logger('verified: ' . $x, LOGGER_DEBUG); if(! $x) { // try again, ignoring the local actor (xchan) cache and refetching the key // from its source $fetched_key = self::get_key($key,$keytype,$result['signer'],true); if ($fetched_key && $fetched_key['public_key']) { $y = rsa_verify($signed_data,$sig_block['signature'],$fetched_key['public_key'],$algorithm); logger('verified: (cache reload) ' . $x, LOGGER_DEBUG); } if (! $y) { logger('verify failed for ' . $result['signer'] . ' alg=' . $algorithm . (($fetched_key['public_key']) ? '' : ' no key')); $sig_block['signature'] = base64_encode($sig_block['signature']); logger('affected sigblock: ' . print_r($sig_block,true)); logger('headers: ' . print_r($headers,true)); logger('server: ' . print_r($_SERVER,true)); return $result; } } $key = (($fetched_key) ? $fetched_key : $cached_key); $result['portable_id'] = $key['portable_id']; $result['header_valid'] = true; if(in_array('digest',$signed_headers)) { $result['content_signed'] = true; $digest = explode('=', $headers['digest'], 2); if($digest[0] === 'SHA-256') $hashalg = 'sha256'; if($digest[0] === 'SHA-512') $hashalg = 'sha512'; if(base64_encode(hash($hashalg,$body,true)) === $digest[1]) { $result['content_valid'] = true; } logger('Content_Valid: ' . (($result['content_valid']) ? 'true' : 'false')); if (! $result['content_valid']) { logger('invalid content signature: data ' . print_r($data,true)); logger('invalid content signature: headers ' . print_r($headers,true)); logger('invalid content signature: body ' . print_r($body,true)); } } return $result; } static function get_key($key,$keytype,$id) { if(is_array($key)) btlogger('key is array: ' . print_r($key,true)); if($key) { if(function_exists($key)) { return $key($id); } return [ 'public_key' => $key ]; } if($keytype === 'zot6') { $key = self::get_zotfinger_key($id); if($key) { return $key; } } if(strpos($id,'#') === false) { $key = self::get_webfinger_key($id); } if(! $key) { $key = self::get_activitystreams_key($id); } return $key; } function convertKey($key) { if(strstr($key,'RSA ')) { return rsatopem($key); } elseif(substr($key,0,5) === 'data:') { return convert_salmon_key($key); } else { return $key; } } /** * @brief * * @param string $id * @return boolean|string * false if no pub key found, otherwise return the pub key */ function get_activitystreams_key($id) { // remove fragment $url = ((strpos($id,'#')) ? substr($id,0,strpos($id,'#')) : $id); $x = q("select * from xchan left join hubloc on xchan_hash = hubloc_hash where hubloc_addr = '%s' or hubloc_id_url = '%s' and hubloc_network in ('zot6', 'activitypub')", dbesc(str_replace('acct:','',$url)), dbesc($url) ); $x = Libzot::zot_record_preferred($x); if($x && $x['xchan_pubkey']) { return [ 'portable_id' => $x['xchan_hash'], 'public_key' => $x['xchan_pubkey'] , 'hubloc' => $x ]; } $r = ActivityStreams::fetch($id); if($r) { if(array_key_exists('publicKey',$r) && array_key_exists('publicKeyPem',$r['publicKey']) && array_key_exists('id',$r['publicKey'])) { if($r['publicKey']['id'] === $id || $r['id'] === $id) { $portable_id = ((array_key_exists('owner',$r['publicKey'])) ? $r['publicKey']['owner'] : EMPTY_STR); return [ 'public_key' => self::convertKey($r['publicKey']['publicKeyPem']), 'portable_id' => $portable_id, 'hubloc' => [] ]; } } } return false; } function get_webfinger_key($id) { $x = q("select * from xchan left join hubloc on xchan_hash = hubloc_hash where hubloc_addr = '%s' or hubloc_id_url = '%s'", dbesc(str_replace('acct:','',$id)), dbesc($id) ); $x = Libzot::zot_record_preferred($x); if($x && $x['xchan_pubkey']) { return [ 'portable_id' => $x['xchan_hash'], 'public_key' => $x['xchan_pubkey'] , 'hubloc' => $x ]; } $wf = Webfinger::exec($id); $key = [ 'portable_id' => '', 'public_key' => '', 'hubloc' => [] ]; if($wf) { if(array_key_exists('properties',$wf) && array_key_exists('https://w3id.org/security/v1#publicKeyPem',$wf['properties'])) { $key['public_key'] = self::convertKey($wf['properties']['https://w3id.org/security/v1#publicKeyPem']); } if(array_key_exists('links', $wf) && is_array($wf['links'])) { foreach($wf['links'] as $l) { if(! (is_array($l) && array_key_exists('rel',$l))) { continue; } if($l['rel'] === 'magic-public-key' && array_key_exists('href',$l) && $key['public_key'] === EMPTY_STR) { $key['public_key'] = self::convertKey($l['href']); } } } } return (($key['public_key']) ? $key : false); } function get_zotfinger_key($id) { $x = q("select * from xchan left join hubloc on xchan_hash = hubloc_hash where hubloc_addr = '%s' or hubloc_id_url = '%s' and hubloc_network = 'zot6'", dbesc(str_replace('acct:','',$id)), dbesc($id) ); if($x && $x[0]['xchan_pubkey']) { return [ 'portable_id' => $x[0]['xchan_hash'], 'public_key' => $x[0]['xchan_pubkey'] , 'hubloc' => $x[0] ]; } $wf = Webfinger::exec($id); $key = [ 'portable_id' => '', 'public_key' => '', 'hubloc' => [] ]; if($wf) { if(array_key_exists('properties',$wf) && array_key_exists('https://w3id.org/security/v1#publicKeyPem',$wf['properties'])) { $key['public_key'] = self::convertKey($wf['properties']['https://w3id.org/security/v1#publicKeyPem']); } if(array_key_exists('links', $wf) && is_array($wf['links'])) { foreach($wf['links'] as $l) { if(! (is_array($l) && array_key_exists('rel',$l))) { continue; } if($l['rel'] === 'http://purl.org/zot/protocol/6.0' && array_key_exists('href',$l) && $l['href'] !== EMPTY_STR) { // The third argument to Zotfinger::exec() tells it not to verify signatures // Since we're inside a function that is fetching keys with which to verify signatures, // this is necessary to prevent infinite loops. $z = \Zotlabs\Lib\Zotfinger::exec($l['href'],null,false); if($z) { $i = Libzot::import_xchan($z['data']); if($i['success']) { $key['portable_id'] = $i['hash']; $x = q("select * from xchan left join hubloc on xchan_hash = hubloc_hash where hubloc_id_url = '%s' and hubloc_network = 'zot6'", dbesc($l['href']) ); if($x) { $key['hubloc'] = $x[0]; } } } } if($l['rel'] === 'magic-public-key' && array_key_exists('href',$l) && $key['public_key'] === EMPTY_STR) { $key['public_key'] = self::convertKey($l['href']); } } } } return (($key['public_key']) ? $key : false); } /** * @brief * * @param array $head * @param string $prvkey * @param string $keyid (optional, default '') * @param boolean $auth (optional, default false) * @param string $alg (optional, default 'sha256') * @param array $encryption [ 'key', 'algorithm' ] or false * @return array */ static function create_sig($head, $prvkey, $keyid = EMPTY_STR, $auth = false, $alg = 'sha256', $encryption = false ) { $return_headers = []; if($alg === 'sha256') { $algorithm = 'rsa-sha256'; } if($alg === 'sha512') { $algorithm = 'rsa-sha512'; } $x = self::sign($head,$prvkey,$alg); $headerval = 'keyId="' . $keyid . '",algorithm="' . $algorithm . '",headers="' . $x['headers'] . '",signature="' . $x['signature'] . '"'; if($encryption) { $x = crypto_encapsulate($headerval,$encryption['key'],$encryption['algorithm']); if(is_array($x)) { $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 => $v) { // strip the request-target virtual header from the output headers if($k === '(request-target)') { continue; } $return_headers[] = $k . ': ' . $v; } } $return_headers[] = $sighead; return $return_headers; } /** * @brief set headers * * @param array $headers * @return void */ static function set_headers($headers) { if($headers && is_array($headers)) { foreach($headers as $h) { header($h); } } } /** * @brief * * @param array $head * @param string $prvkey * @param string $alg (optional) default 'sha256' * @return array */ static function sign($head, $prvkey, $alg = 'sha256') { $ret = []; $headers = ''; $fields = ''; logger('signing: ' . print_r($head,true), LOGGER_DATA); if($head) { foreach($head as $k => $v) { $headers .= strtolower($k) . ': ' . trim($v) . "\n"; if($fields) $fields .= ' '; $fields .= strtolower($k); } // strip the trailing linefeed $headers = rtrim($headers,"\n"); } $sig = base64_encode(rsa_sign($headers,$prvkey,$alg)); $ret['headers'] = $fields; $ret['signature'] = $sig; return $ret; } /** * @brief * * @param string $header * @return array associate array with * - \e string \b keyID * - \e string \b algorithm * - \e array \b headers * - \e string \b signature */ static function parse_sigheader($header) { $ret = []; $matches = []; // if the header is encrypted, decrypt with (default) site private key and continue if(preg_match('/iv="(.*?)"/ism',$header,$matches)) $header = self::decrypt_sigheader($header); if(preg_match('/keyId="(.*?)"/ism',$header,$matches)) $ret['keyId'] = $matches[1]; if(preg_match('/algorithm="(.*?)"/ism',$header,$matches)) $ret['algorithm'] = $matches[1]; if(preg_match('/headers="(.*?)"/ism',$header,$matches)) $ret['headers'] = explode(' ', $matches[1]); if(preg_match('/signature="(.*?)"/ism',$header,$matches)) $ret['signature'] = base64_decode(preg_replace('/\s+/','',$matches[1])); if(($ret['signature']) && ($ret['algorithm']) && (! $ret['headers'])) $ret['headers'] = [ 'date' ]; return $ret; } /** * @brief * * @param string $header * @param string $prvkey (optional), if not set use site private key * @return array|string associative array, empty string if failue * - \e string \b iv * - \e string \b key * - \e string \b alg * - \e string \b data */ static function decrypt_sigheader($header, $prvkey = null) { $iv = $key = $alg = $data = null; if(! $prvkey) { $prvkey = get_config('system', 'prvkey'); } $matches = []; if(preg_match('/iv="(.*?)"/ism',$header,$matches)) $iv = $matches[1]; if(preg_match('/key="(.*?)"/ism',$header,$matches)) $key = $matches[1]; if(preg_match('/alg="(.*?)"/ism',$header,$matches)) $alg = $matches[1]; if(preg_match('/data="(.*?)"/ism',$header,$matches)) $data = $matches[1]; if($iv && $key && $alg && $data) { return crypto_unencapsulate([ 'encrypted' => true, 'iv' => $iv, 'key' => $key, 'alg' => $alg, 'data' => $data ] , $prvkey); } return ''; } }