friendica/mod/dfrn_poll.php

<?php



require_once('include/items.php');
require_once('include/auth.php');


function dfrn_poll_init(&$a) {


	$dfrn_id         = ((x($_GET,'dfrn_id'))         ? $_GET['dfrn_id']              : '');
	$type            = ((x($_GET,'type'))            ? $_GET['type']                 : 'data');
	$last_update     = ((x($_GET,'last_update'))     ? $_GET['last_update']          : '');
	$destination_url = ((x($_GET,'destination_url')) ? $_GET['destination_url']      : '');
	$challenge       = ((x($_GET,'challenge'))       ? $_GET['challenge']            : '');
	$sec             = ((x($_GET,'sec'))             ? $_GET['sec']                  : '');
	$dfrn_version    = ((x($_GET,'dfrn_version'))    ? (float) $_GET['dfrn_version'] : 2.0);

	$direction = (-1);


	if(strpos($dfrn_id,':') == 1) {
		$direction = intval(substr($dfrn_id,0,1));
		$dfrn_id   = substr($dfrn_id,2);
	}

	if(($dfrn_id === '') && (! x($_POST,'dfrn_id')) && ($a->argc > 1)) {
		header("Content-type: application/atom+xml");
		$o = get_feed_for($a, '*', $a->argv[1],$last_update);
		echo $o;
		killme();
	}

	if(($type === 'profile') && (! strlen($sec))) {

		$sql_extra = '';
		switch($direction) {
			case (-1):
				$sql_extra = sprintf(" AND ( `dfrn-id` = '%s' OR `issued-id` = '%s' ) ", dbesc($dfrn_id),dbesc($dfrn_id));
				$my_id = $dfrn_id;
				break;
			case 0:
				$sql_extra = sprintf(" AND `issued-id` = '%s' AND `duplex` = 1 ", dbesc($dfrn_id));
				$my_id = '1:' . $dfrn_id;
				break;
			case 1:
				$sql_extra = sprintf(" AND `dfrn-id` = '%s' AND `duplex` = 1 ", dbesc($dfrn_id));
				$my_id = '0:' . $dfrn_id;
				break;
			default:
				goaway($a->get_baseurl());
				break; // NOTREACHED
		}

		$r = q("SELECT `contact`.*, `user`.`username`, `user`.`nickname` 
			FROM `contact` LEFT JOIN `user` ON `contact`.`uid` = `user`.`uid`
			WHERE `contact`.`blocked` = 0 AND `contact`.`pending` = 0 
			AND `user`.`nickname` = '%s' $sql_extra LIMIT 1",
			dbesc($a->argv[1])
		);
		
		if(count($r)) {

			$s = fetch_url($r[0]['poll'] . '?dfrn_id=' . $my_id . '&type=profile-check');

			logger("dfrn_poll: old profile returns " . $s, LOGGER_DATA);

			if(strlen($s)) {

				$xml = simplexml_load_string($s);

				if((int) $xml->status == 1) {
					$_SESSION['authenticated'] = 1;
					$_SESSION['visitor_id'] = $r[0]['id'];
					notice( $r[0]['username'] . t(' welcomes ') . $r[0]['name'] . EOL);
					// Visitors get 1 day session.
					$session_id = session_id();
					$expire = time() + 86400;
					q("UPDATE `session` SET `expire` = '%s' WHERE `sid` = '%s' LIMIT 1",
						dbesc($expire),
						dbesc($session_id)
					); 
				}
			}
			$profile = $r[0]['nickname'];
			goaway((strlen($destination_url)) ? $destination_url : $a->get_baseurl() . '/profile/' . $profile);
		}
		goaway($a->get_baseurl());

	}

	if($type === 'profile-check') {

		if((strlen($challenge)) && (strlen($sec))) {

			q("DELETE FROM `profile_check` WHERE `expire` < " . intval(time()));
			$r = q("SELECT * FROM `profile_check` WHERE `sec` = '%s' ORDER BY `expire` DESC LIMIT 1",
				dbesc($sec)
			);
			if(! count($r)) {
				xml_status(3);
				// NOTREACHED
			}
			$orig_id = $r[0]['dfrn_id'];
			if(strpos(':',$orig_id))
				$orig_id = substr($orig_id,2);

			$c = q("SELECT * FROM `contact` WHERE `id` = %d LIMIT 1",
				intval($r[0]['cid'])
			);
			if(! count($c)) {
				xml_status(3);
			}
			$contact = $c[0];

			$sent_dfrn_id = hex2bin($dfrn_id);
			$challenge    = hex2bin($challenge);

			$final_dfrn_id = '';

			if(($contact['duplex']) && strlen($contact['prvkey'])) {
				openssl_private_decrypt($sent_dfrn_id,$final_dfrn_id,$contact['prvkey']);
				openssl_private_decrypt($challenge,$decoded_challenge,$contact['prvkey']);
			}
			else {
				openssl_public_decrypt($sent_dfrn_id,$final_dfrn_id,$contact['pubkey']);
				openssl_public_decrypt($challenge,$decoded_challenge,$contact['pubkey']);
			}

			$final_dfrn_id = substr($final_dfrn_id, 0, strpos($final_dfrn_id, '.'));

			if(strpos($final_dfrn_id,':') == 1)
				$final_dfrn_id = substr($final_dfrn_id,2);

			if($final_dfrn_id != $orig_id) {

				// did not decode properly - cannot trust this site 
				xml_status(3);
			}

			header("Content-type: text/xml");
			echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?><dfrn_poll><status>0</status><challenge>$decoded_challenge</challenge><sec>$sec</sec></dfrn_poll>";
			killme();
			// NOTREACHED
		}
		else {
				// old protocol

			switch($direction) {
				case 1:
					$dfrn_id = '0:' . $dfrn_id;
					break;
				case 0:
					$dfrn_id = '1:' . $dfrn_id;
					break;
				default:
					break;
			}


			q("DELETE FROM `profile_check` WHERE `expire` < " . intval(time()));
			$r = q("SELECT * FROM `profile_check` WHERE `dfrn_id` = '%s' ORDER BY `expire` DESC",
				dbesc($dfrn_id));
			if(count($r)) {
				xml_status(1);
				return; // NOTREACHED
			}
			xml_status(0);
			return; // NOTREACHED
		}
	}

}



function dfrn_poll_post(&$a) {

	$dfrn_id      = ((x($_POST,'dfrn_id'))      ? $_POST['dfrn_id']              : '');
	$challenge    = ((x($_POST,'challenge'))    ? $_POST['challenge']            : '');
	$url          = ((x($_POST,'url'))          ? $_POST['url']                  : '');
	$dfrn_version = ((x($_POST,'dfrn_version')) ? (float) $_POST['dfrn_version'] : 2.0);

	$direction    = (-1);
	if(strpos($dfrn_id,':') == 1) {
		$direction = intval(substr($dfrn_id,0,1));
		$dfrn_id   = substr($dfrn_id,2);
	}


	$r = q("SELECT * FROM `challenge` WHERE `dfrn-id` = '%s' AND `challenge` = '%s' LIMIT 1",
		dbesc($dfrn_id),
		dbesc($challenge)
	);

	if(! count($r))
		killme();

	$type = $r[0]['type'];
	$last_update = $r[0]['last_update'];

	$r = q("DELETE FROM `challenge` WHERE `dfrn-id` = '%s' AND `challenge` = '%s' LIMIT 1",
		dbesc($dfrn_id),
		dbesc($challenge)
	);


	$sql_extra = '';
	switch($direction) {
		case (-1):
			$sql_extra = sprintf(" AND `issued-id` = '%s' ", dbesc($dfrn_id));
			$my_id = $dfrn_id;
			break;
		case 0:
			$sql_extra = sprintf(" AND `issued-id` = '%s' AND `duplex` = 1 ", dbesc($dfrn_id));
			$my_id = '1:' . $dfrn_id;
			break;
		case 1:
			$sql_extra = sprintf(" AND `dfrn-id` = '%s' AND `duplex` = 1 ", dbesc($dfrn_id));
			$my_id = '0:' . $dfrn_id;
			break;
		default:
			goaway($a->get_baseurl());
			break; // NOTREACHED
	}


	$r = q("SELECT * FROM `contact` WHERE `blocked` = 0 AND `pending` = 0 $sql_extra LIMIT 1");


	if(! count($r))
		killme();

	$owner_uid = $r[0]['uid'];
	$contact_id = $r[0]['id']; 


	if($type === 'reputation' && strlen($url)) {
		$r = q("SELECT * FROM `contact` WHERE `url` = '%s' AND `uid` = %d LIMIT 1",
			dbesc($url),
			intval($owner_uid)
		);
		$reputation = 0;
		$text = '';

		if(count($r)) {
			$reputation = $r[0]['rating'];
			$text = $r[0]['reason'];

			if($r[0]['id'] == $contact_id) {	// inquiring about own reputation not allowed
				$reputation = 0;
				$text = '';
			}
		}

		echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?>
		<reputation>
			<url>$url</url>
			<rating>$reputation</rating>
			<description>$text</description>
		</reputation>
		";
		killme();
		// NOTREACHED
	}
	else {
		header("Content-type: application/atom+xml");
		$o = get_feed_for($a,$dfrn_id, $a->argv[1], $last_update, $direction);
		echo $o;
		killme();

	}
}

function dfrn_poll_content(&$a) {

	$dfrn_id         = ((x($_GET,'dfrn_id'))         ? $_GET['dfrn_id']              : '');
	$type            = ((x($_GET,'type'))            ? $_GET['type']                 : 'data');
	$last_update     = ((x($_GET,'last_update'))     ? $_GET['last_update']          : '');
	$destination_url = ((x($_GET,'destination_url')) ? $_GET['destination_url']      : '');
	$sec             = ((x($_GET,'sec'))             ? $_GET['sec']                  : '');
	$dfrn_version    = ((x($_GET,'dfrn_version'))    ? (float) $_GET['dfrn_version'] : 2.0);

	$direction = (-1);
	if(strpos($dfrn_id,':') == 1) {
		$direction = intval(substr($dfrn_id,0,1));
		$dfrn_id = substr($dfrn_id,2);
	}


	if($dfrn_id != '') {
		// initial communication from external contact
		$hash = random_string();

		$status = 0;

		$r = q("DELETE FROM `challenge` WHERE `expire` < " . intval(time()));

		if($type !== 'profile') {
			$r = q("INSERT INTO `challenge` ( `challenge`, `dfrn-id`, `expire` , `type`, `last_update` )
				VALUES( '%s', '%s', '%s', '%s', '%s' ) ",
				dbesc($hash),
				dbesc($dfrn_id),
				intval(time() + 60 ),
				dbesc($type),
				dbesc($last_update)
			);
		}
		$sql_extra = '';
		switch($direction) {
			case (-1):
				if($type === 'profile')
					$sql_extra = sprintf(" AND ( `dfrn-id` = '%s' OR `issued-id` = '%s' ) ", dbesc($dfrn_id),dbesc($dfrn_id));
				else
					$sql_extra = sprintf(" AND `issued-id` = '%s' ", dbesc($dfrn_id));
				$my_id = $dfrn_id;
				break;
			case 0:
				$sql_extra = sprintf(" AND `issued-id` = '%s' AND `duplex` = 1 ", dbesc($dfrn_id));
				$my_id = '1:' . $dfrn_id;
				break;
			case 1:
				$sql_extra = sprintf(" AND `dfrn-id` = '%s' AND `duplex` = 1 ", dbesc($dfrn_id));
				$my_id = '0:' . $dfrn_id;
				break;
			default:
				goaway($a->get_baseurl());
				break; // NOTREACHED
		}

		$r = q("SELECT `contact`.*, `user`.`username`, `user`.`nickname` 
			FROM `contact` LEFT JOIN `user` ON `contact`.`uid` = `user`.`uid`
			WHERE `contact`.`blocked` = 0 AND `contact`.`pending` = 0 
			AND `user`.`nickname` = '%s' $sql_extra LIMIT 1",
			dbesc($a->argv[1])
		);

		if(count($r)) {

			$challenge = '';
			$encrypted_id = '';
			$id_str = $my_id . '.' . mt_rand(1000,9999);

			if($r[0]['duplex'] && strlen($r[0]['pubkey'])) {
				openssl_public_encrypt($hash,$challenge,$r[0]['pubkey']);
				openssl_public_encrypt($id_str,$encrypted_id,$r[0]['pubkey']);
			}
			else {
				openssl_private_encrypt($hash,$challenge,$r[0]['prvkey']);
				openssl_private_encrypt($id_str,$encrypted_id,$r[0]['prvkey']);
			}

			$challenge = bin2hex($challenge);
			$encrypted_id = bin2hex($encrypted_id);
		}
		else {
			$status = 1;
			$challenge = '';
			$encrypted_id = '';
		}

		if(($type === 'profile') && (strlen($sec))) {
			// URL reply

			$s = fetch_url($r[0]['poll'] 
				. '?dfrn_id=' . $encrypted_id 
				. '&type=profile-check'
				. '&dfrn_version=' . DFRN_PROTOCOL_VERSION
				. '&challenge=' . $challenge
				. '&sec=' . $sec
			);

			logger("dfrn_poll: sec profile: " . $s, LOGGER_DATA);

			if(strlen($s) && strstr($s,'<?xml')) {

				$xml = simplexml_load_string($s);

				logger('dfrn_poll: profile: parsed xml: ' . print_r($xml,true), LOGGER_DATA);

				logger('dfrn_poll: secure profile: challenge: ' . $xml->challenge . ' expecting ' . $hash);
				logger('dfrn_poll: secure profile: sec: ' . $xml->sec . ' expecting ' . $sec);
 
				
				if(((int) $xml->status == 0) && ($xml->challenge == $hash)  && ($xml->sec == $sec)) {
					$_SESSION['authenticated'] = 1;
					$_SESSION['visitor_id'] = $r[0]['id'];
					notice( $r[0]['username'] . t(' welcomes ') . $r[0]['name'] . EOL);
					// Visitors get 1 day session.
					$session_id = session_id();
					$expire = time() + 86400;
					q("UPDATE `session` SET `expire` = '%s' WHERE `sid` = '%s' LIMIT 1",
						dbesc($expire),
						dbesc($session_id)
					); 
				}
				$profile = $r[0]['nickname'];
				goaway((strlen($destination_url)) ? $destination_url : $a->get_baseurl() . '/profile/' . $profile);
			}
			goaway($a->get_baseurl());
			// NOTREACHED

		}
		else {
			// XML reply
			header("Content-type: text/xml");
			echo '<?xml version="1.0" encoding="UTF-8"?>' . "\r\n"
				. '<dfrn_poll>' . "\r\n"
				. "\t" . '<status>' . $status . '</status>' . "\r\n"
				. "\t" . '<dfrn_version>' . DFRN_PROTOCOL_VERSION . '</dfrn_version>' . "\r\n"
				. "\t" . '<dfrn_id>' . $encrypted_id . '</dfrn_id>' . "\r\n"
				. "\t" . '<challenge>' . $challenge . '</challenge>' . "\r\n"
				. '</dfrn_poll>' . "\r\n" ;
			killme();
			// NOTREACHED
		}
	}
}