streams/include/security.php

<?php

use Code\Lib\AConfig;
use Code\Lib\Channel;
use Code\Extend\Hook;
use Code\Lib\Time;
use Code\Storage\Stdio;
/**
 * @file include/security.php
 *
 * @brief Some security related functions.
 */

/**
 * @param array $user_record account_id
 * @param array|bool $channel
 * @param bool $login_initial default false
 * @param bool $interactive default false
 * @param bool $return
 * @param bool $update_lastlog
 */
function authenticate_success($user_record, $channel = false, $login_initial = false, $interactive = false, $return = false, $update_lastlog = false)
{

    $_SESSION['addr'] = $_SERVER['REMOTE_ADDR'];

    $lastlog_updated = false;

    if (x($user_record, 'account_id')) {
        App::$account = $user_record;
        $_SESSION['account_id'] = $user_record['account_id'];
        $_SESSION['authenticated'] = 1;

        $canChangeChannel = empty($_SESSION['2FA_REQUIRED']);
        if (!empty($_SESSION['2FA_VERIFIED'])) {
            $canChangeChannel = true;
        }

        if ($canChangeChannel) {

            if ($channel) {
                $uid_to_load = $channel['channel_id'];
            }

            if (!isset($uid_to_load)) {
                $uid_to_load = (((x($_SESSION, 'uid')) && (intval($_SESSION['uid'])))
                    ? intval($_SESSION['uid'])
                    : intval(App::$account['account_default_channel'])
                );
            }

            if ($uid_to_load) {
                change_channel($uid_to_load);
            }
        }

        if (($login_initial || $update_lastlog) && (! (isset($_SESSION['sudo']) && $_SESSION['sudo']))) {
            q(
                "update account set account_lastlog = '%s' where account_id = %d",
                dbesc(Time::convert()),
                intval($_SESSION['account_id'])
            );
            App::$account['account_lastlog'] = Time::convert();
            $lastlog_updated = true;
            Hook::call('logged_in', App::$account);
        }
    }

    if ($login_initial && $interactive) {
        Hook::call('logged_in', $user_record);
        // might want to log success here
    }

    if (!empty($_SESSION['2FA_REQUIRED']) && !$_SESSION['2FA_VERIFIED']
        && !in_array(App::$module, ['totp_check', 'dav', 'cdav', 'api', 'addressbook', 'calendar'], true)) {
        goaway(z_root() . '/totp_check');
    }

    if ($return || x($_SESSION, 'workflow')) {
        unset($_SESSION['workflow']);
        return;
    }

    if ((App::$module !== 'home') && x($_SESSION, 'login_return_url') && strlen($_SESSION['login_return_url'])) {
        $return_url = $_SESSION['login_return_url'];

        // don't let members get redirected to a raw ajax page update - this can happen
        // if DHCP changes the IP address at an unfortunate time and paranoia is turned on
        if (strstr($return_url, 'update')) {
            $return_url = '';
        }

        unset($_SESSION['login_return_url']);
        goaway(z_root() . '/' . $return_url);
    }

    /* This account has never created a channel. Send them to new_channel by default */

    if (App::$module === 'login') {
        $r = q(
            "select count(channel_id) as total from channel where channel_account_id = %d and channel_removed = 0 ",
            intval(App::$account['account_id'])
        );
        if (($r) && (! $r[0]['total'])) {
            goaway(z_root() . '/new_channel');
        }
    }

    /* else just return */
}

function atoken_login($atoken)
{

    if (! $atoken) {
        return false;
    }
    if (App::$cmd === 'channel' && argv(1)) {
        $channel = Channel::from_username(argv(1));
        if (perm_is_allowed($channel['channel_id'], $atoken['xchan_hash'], 'delegate')) {
            $_SESSION['delegate_channel'] = $channel['channel_id'];
            $_SESSION['delegate'] = $atoken['xchan_hash'];
            $_SESSION['account_id'] = intval($channel['channel_account_id']);
            change_channel($channel['channel_id']);
            return;
        }
    }

    $_SESSION['authenticated'] = 1;
    $_SESSION['visitor_id'] = $atoken['xchan_hash'];
    $_SESSION['atoken'] = $atoken['atoken_id'];

    App::set_observer($atoken);

    return true;
}

/**
 * @brief
 *
 * @param array $atoken
 * @return array|null
 */
function atoken_xchan($atoken)
{

    $c = Channel::from_id($atoken['atoken_uid']);
    if ($c) {
        return [
            'atoken_id' => $atoken['atoken_id'],
            'xchan_hash' =>  substr($c['channel_hash'], 0, 16) . '.' . $atoken['atoken_guid'],
            'xchan_name' => $atoken['atoken_name'],
            'xchan_addr' => 'guest:' . $atoken['atoken_name'] . '@' . App::get_hostname(),
            'xchan_network' => 'token',
            'xchan_url' => z_root() . '/guest/' . substr($c['channel_hash'], 0, 16) . '.' . $atoken['atoken_guid'],
            'xchan_hidden' => 1,
            'xchan_photo_mimetype' => 'image/png',
            'xchan_photo_l' => z_root() . '/' . Channel::get_default_profile_photo(300),
            'xchan_photo_m' => z_root() . '/' . Channel::get_default_profile_photo(80),
            'xchan_photo_s' => z_root() . '/' . Channel::get_default_profile_photo(48)
        ];
    }

    return null;
}

function atoken_delete($atoken_id)
{

    $r = q(
        "select * from atoken where atoken_id = %d",
        intval($atoken_id)
    );
    if (! $r) {
        return;
    }

    $c = q(
        "select channel_id, channel_hash from channel where channel_id = %d",
        intval($r[0]['atoken_uid'])
    );
    if (! $c) {
        return;
    }

    $atoken_xchan = substr($c[0]['channel_hash'], 0, 16) . '.' . $r[0]['atoken_guid'];

    q(
        "delete from atoken where atoken_id = %d",
        intval($atoken_id)
    );
    q(
        "delete from abook where abook_channel = %d and abook_xchan = '%s'",
        intval($c[0]['channel_id']),
        dbesc($atoken_xchan)
    );

    q(
        "delete from abconfig where chan = %d and xchan = '%s'",
        intval($c[0]['channel_id']),
        dbesc($atoken_xchan)
    );
}

/**
 * @brief
 *
 * In order for atoken logins to create content (such as posts) they need a stored xchan.
 * we'll create one on atoken creation; it can't really ever go away but perhaps
 * @fixme we should set xchan_deleted if it's expired or removed
 *
 * @param array $xchan
 * @return void|bool
 */
function atoken_create_xchan($xchan)
{

    $r = q(
        "select xchan_hash from xchan where xchan_hash = '%s'",
        dbesc($xchan['xchan_hash'])
    );
    if ($r) {
        return;
    }

    $xchan['xchan_guid'] = $xchan['xchan_hash'];

    $store = [];
    foreach ($xchan as $k => $v) {
        if (strpos($k, 'xchan_') === 0) {
            $store[$k] = $v;
        }
    }

    $r = xchan_store_lowlevel($store);

    return true;
}

function atoken_abook($uid, $xchan_hash)
{

    if (substr($xchan_hash, 16, 1) != '.') {
        return false;
    }

    $r = q(
        "select channel_hash from channel where channel_id = %d limit 1",
        intval($uid)
    );

    if (! $r) {
        return false;
    }

    $x = q(
        "select * from atoken where atoken_uid = %d and atoken_guid = '%s'",
        intval($uid),
        dbesc(substr($xchan_hash, 17))
    );

    if ($x) {
        $xchan = atoken_xchan($x[0]);
        $xchan['abook_blocked'] = 0;
        $xchan['abook_ignored'] = 0;
        $xchan['abook_pending'] = 0;
        return $xchan;
    }

    return false;
}


function pseudo_abook($xchan)
{
    if (! $xchan) {
        return false;
    }

    // set abook_pseudo to flag that we aren't really connected.

    $xchan['abook_pseudo']  = 1;
    $xchan['abook_blocked'] = 0;
    $xchan['abook_ignored'] = 0;
    $xchan['abook_pending'] = 0;

    return $xchan;
}


/**
 * @brief Change to another channel with current logged-in account.
 *
 * @param int $change_channel The channel_id of the channel you want to change to
 *
 * @return bool|array false or channel record of the new channel
 */
function change_channel($change_channel)
{

    $ret = false;

    if ($change_channel) {
        $r = q(
            "select channel.*, xchan.* from channel left join xchan on channel.channel_hash = xchan.xchan_hash where channel_id = %d and channel_account_id = %d and channel_removed = 0 limit 1",
            intval($change_channel),
            intval(get_account_id())
        );

        // It's not there.  Is this an administrator, and is this the sys channel?
        if (! $r) {
            if (is_developer() || is_site_admin()) {
                $r = q(
                    "select channel.*, xchan.* from channel left join xchan on channel.channel_hash = xchan.xchan_hash where channel_id = %d and channel_system = 1 and channel_removed = 0 limit 1",
                    intval($change_channel)
                );
            }
        }

        if ($r) {
            $hash = $r[0]['channel_hash'];
            $_SESSION['uid'] = intval($r[0]['channel_id']);
            App::set_channel($r[0]);
            $_SESSION['theme'] = $r[0]['channel_theme'];
            $_SESSION['mobile_theme'] = get_pconfig(local_channel(), 'system', 'mobile_theme');
            $_SESSION['cloud_tiles'] = get_pconfig(local_channel(), 'system', 'cloud_tiles');
            $_SESSION['loadtime_channel'] = get_pconfig(local_channel(), 'system', 'loadtime_channel', '2000-01-01 00:00:00');
            $_SESSION['loadtime_stream'] = get_pconfig(local_channel(), 'system', 'loadtime_stream', '2000-01-01 00:00:00');
            $_SESSION['loadtime_pubstream'] = get_pconfig(local_channel(), 'system', 'loadtime_pubstream', '2000-01-01 00:00:00');
            $_SESSION['seen_items'] = get_pconfig(local_channel(), 'system', 'seen_items', []);
    
            date_default_timezone_set($r[0]['channel_timezone']);

            // Update the active timestamp at most once a day

            if (substr($r[0]['channel_active'], 0, 10) !== substr(Time::convert(), 0, 10) && (! (isset($_SESSION['sudo']) && $_SESSION['sudo']))) {
                $z = q(
                    "UPDATE channel SET channel_active = '%s' WHERE channel_id = %d",
                    dbesc(Time::convert()),
                    intval($r[0]['channel_id'])
                );
            }
            $ret = $r[0];
        }
        $x = xchan_match([ 'xchan_hash' => $hash ]);
        if ($x) {
            $_SESSION['my_url'] = $x['xchan_url'];
            $_SESSION['my_address'] = Channel::get_webfinger($r[0]);

            App::set_observer($x);
            App::set_perms(get_all_perms(local_channel(), $hash));
        }
        if (! is_dir('store/' . $r[0]['channel_address'])) {
            Stdio::mkdir('store/' . $r[0]['channel_address'], STORAGE_DEFAULT_PERMISSIONS, true);
        }

        $arr = [ 'channel_id' => $change_channel, 'chanx' => $ret ];
        Hook::call('change_channel', $arr);
    }

    return $ret;
}

/**
 * @brief Creates an additional SQL where statement to check permissions.
 *
 * @param int $owner_id
 * @param bool $remote_observer (optional) use current observer if unset
 * @param $table (optional)
 *
 * @return string additional SQL where statement
 */


function permissions_sql($owner_id, $remote_observer = null, $table = '', $token = EMPTY_STR)
{

    $local_channel = local_channel();

    /**
     * Construct permissions
     *
     * default permissions - anonymous user
     */

    if ($table) {
        $table .= '.';
    }

    $sql = " AND {$table}allow_cid = ''
			 AND {$table}allow_gid = ''
			 AND {$table}deny_cid  = ''
			 AND {$table}deny_gid  = ''
	";

    /**
     * Profile owner - everything is visible
     */

    if (($local_channel) && ($local_channel == $owner_id)) {
        return EMPTY_STR;
    }


    /**
     * Authenticated visitor.
     */

    else {
        $observer = ((! is_null($remote_observer)) ? $remote_observer : get_observer_hash());

        if ($observer) {
            $sec = get_security_ids($owner_id, $observer);

            if ($token) {
                if (! array_key_exists('allow_cid', $sec)) {
                    $sec['allow_cid'] = [];
                }
                $sec['allow_cid'][] = 'token:' . $token;
            }

            // always allow the channel owner, even if authenticated as a visitor

            if ($sec['channel_id']) {
                foreach ($sec['channel_id'] as $ch) {
                    if ($observer === $ch) {
                        return EMPTY_STR;
                    }
                }
            }

            if (is_array($sec['allow_cid']) && count($sec['allow_cid'])) {
                $ca = [];
                foreach ($sec['allow_cid'] as $c) {
                    $ca[] = '<' . $c . '>';
                }
                $cs = implode('|', $ca);
            } else {
                $cs = '<<>>'; // should be impossible to match
            }

            if (is_array($sec['allow_gid']) && count($sec['allow_gid'])) {
                $ga = [];
                foreach ($sec['allow_gid'] as $g) {
                    $ga[] = '<' . $g . '>';
                }
                $gs = implode('|', $ga);
            } else {
                $gs = '<<>>'; // should be impossible to match
            }

            $regexop = db_getfunc('REGEXP');
            $sql = sprintf(
                " AND ( NOT ({$table}deny_cid $regexop '%s' OR {$table}deny_gid $regexop '%s')
				  AND ( {$table}allow_cid $regexop '%s' OR {$table}allow_gid $regexop '%s' OR ( {$table}allow_cid = '' AND {$table}allow_gid = '') )
				  )
				",
                dbesc($cs),
                dbesc($gs),
                dbesc($cs),
                dbesc($gs)
            );
        }

        /*
         * OCAP token access
         */

        elseif ($token) {
            $sql = " and ( {$table}allow_cid like '" . protect_sprintf('%<token:' . $token . '>%') .
            "' OR ( {$table}allow_cid = '' AND {$table}allow_gid = '' AND {$table}deny_cid = '' AND {$table}deny_gid = '' ) )";
        }
    }

    return $sql;
}

/**
 * @brief Creates an additional SQL where statement to check permissions for an item.
 *
 * @param int $owner_id
 * @param bool $remote_observer (optional) use current observer if unset
 *
 * @return string additional SQL where statement
 */

function item_permissions_sql($owner_id, $remote_observer = null)
{

    $local_channel = local_channel();

    /**
     * Construct permissions
     *
     * default permissions - anonymous user
     */

    $sql = " AND item_private = 0 ";

    /**
     * Profile owner - everything is visible
     */

    if (($local_channel) && ($local_channel == $owner_id)) {
        $sql = '';
    }

    /**
     * Authenticated visitor.
     */

    else {
        $observer = (($remote_observer) ? $remote_observer : get_observer_hash());

        if ($observer) {
            $sec = get_security_ids($owner_id, $observer);

            // always allow the channel owner, even if authenticated as a visitor

            if ($sec['channel_id']) {
                foreach ($sec['channel_id'] as $ch) {
                    if ($observer === $ch) {
                        return EMPTY_STR;
                    }
                }
            }

            if (is_array($sec['allow_cid']) && count($sec['allow_cid'])) {
                $ca = [];
                foreach ($sec['allow_cid'] as $c) {
                    $ca[] = '<' . $c . '>';
                }
                $cs = implode('|', $ca);
            } else {
                $cs = '<<>>'; // should be impossible to match
            }

            if (is_array($sec['allow_gid']) && count($sec['allow_gid'])) {
                $ga = [];
                foreach ($sec['allow_gid'] as $g) {
                    $ga[] = '<' . $g . '>';
                }
                $gs = implode('|', $ga);
            } else {
                $gs = '<<>>'; // should be impossible to match
            }

            // This function is often called without an $owner_id in places where this could not be
            // determined in advance. The ACL fields will usually not contain the original author or owner
            // so we will also check for author_xchan and owner_xchan to account for this ACL deficiency.

            $regexop = db_getfunc('REGEXP');
            $sql = sprintf(
                " AND ( author_xchan = '%s' OR owner_xchan = '%s' OR 
				(( NOT (deny_cid $regexop '%s' OR deny_gid $regexop '%s')
				AND ( allow_cid $regexop '%s' OR allow_gid $regexop '%s' OR ( allow_cid = '' AND allow_gid = '' AND item_private = 0 ))
				)))
				",
                dbesc($observer),
                dbesc($observer),
                dbesc($cs),
                dbesc($gs),
                dbesc($cs),
                dbesc($gs)
            );
        }
    }

    return $sql;
}

/**
 * @param string $observer_hash
 *
 * @return string additional SQL where statement
 */

function public_permissions_sql($observer_hash)
{

    $owner_id = 0;

    if ($observer_hash) {
        $sec = get_security_ids($owner_id, $observer_hash);

        if (is_array($sec['allow_cid']) && count($sec['allow_cid'])) {
            $ca = [];
            foreach ($sec['allow_cid'] as $c) {
                $ca[] = '<' . $c . '>';
            }
            $cs = implode('|', $ca);
        } else {
            $cs = '<<>>'; // should be impossible to match
        }

        if (is_array($sec['allow_gid']) && count($sec['allow_gid'])) {
            $ga = [];
            foreach ($sec['allow_gid'] as $g) {
                $ga[] = '<' . $g . '>';
            }
            $gs = implode('|', $ga);
        } else {
            $gs = '<<>>'; // should be impossible to match
        }

        $regexop = db_getfunc('REGEXP');
        $sql = sprintf(
            " AND ( NOT (deny_cid $regexop '%s' OR deny_gid $regexop '%s')
			  AND ( allow_cid $regexop '%s' OR allow_gid $regexop '%s' OR ( allow_cid = '' AND allow_gid = '' AND item_private = 0) )
			  )
			",
            dbesc($cs),
            dbesc($gs),
            dbesc($cs),
            dbesc($gs)
        );
    } else {
        $sql = " and item_private = 0 ";
    }

    return $sql;
}

/*
 * Functions used to protect against Cross-Site Request Forgery
 * The security token has to base on at least one value that an attacker can't know - here it's the session ID and the private key.
 * In this implementation, a security token is reusable (if the user submits a form, goes back and resubmits the form, maybe with small changes;
 * or if the security token is used for ajax-calls that happen several times), but only valid for a certain amout of time (3hours).
 * The "typename" seperates the security tokens of different types of forms. This could be relevant in the following case:
 *	  A security token is used to protekt a link from CSRF (e.g. the "delete this profile"-link).
 *    If the new page contains by any chance external elements, then the used security token is exposed by the referrer.
 *    Actually, important actions should not be triggered by Links / GET-Requests at all, but somethimes they still are,
 *    so this mechanism brings in some damage control (the attacker would be able to forge a request to a form of this type, but not to forms of other types).
 */
function get_form_security_token($typename = '')
{

    $timestamp = time();
    $sec_hash = hash('whirlpool', App::$observer['xchan_guid'] . ((local_channel()) ? App::$channel['channel_prvkey'] : '') . session_id() . $timestamp . $typename);

    return $timestamp . '.' . $sec_hash;
}

function check_form_security_token($typename = '', $formname = 'form_security_token')
{
    if (!x($_REQUEST, $formname)) {
        return false;
    }
    $hash = $_REQUEST[$formname];

    $max_livetime = 10800; // 3 hours

    $x = explode('.', $hash);
    if (time() > (IntVal($x[0]) + $max_livetime)) {
        return false;
    }

    $sec_hash = hash('whirlpool', App::$observer['xchan_guid'] . ((local_channel()) ? App::$channel['channel_prvkey'] : '') . session_id() . $x[0] . $typename);

    return ($sec_hash == $x[1]);
}

function check_form_security_std_err_msg()
{
    return t('The form security token was not correct. This probably happened because the form has been opened for too long (>3 hours) before submitting it.') . EOL;
}
function check_form_security_token_redirectOnErr($err_redirect, $typename = '', $formname = 'form_security_token')
{
    if (!check_form_security_token($typename, $formname)) {
        logger('check_form_security_token failed: user ' . App::$observer['xchan_name'] . ' - form element ' . $typename);
        logger('check_form_security_token failed: _REQUEST data: ' . print_r($_REQUEST, true), LOGGER_DATA);
        notice(check_form_security_std_err_msg());
        goaway(z_root() . $err_redirect);
    }
}
function check_form_security_token_ForbiddenOnErr($typename = '', $formname = 'form_security_token')
{
    if (!check_form_security_token($typename, $formname)) {
        logger('check_form_security_token failed: user ' . App::$observer['xchan_name'] . ' - form element ' . $typename);
        logger('check_form_security_token failed: _REQUEST data: ' . print_r($_REQUEST, true), LOGGER_DATA);
        header('HTTP/1.1 403 Forbidden');
        killme();
    }
}


function get_security_ids($channel_id, $ob_hash)
{

    $ret = [
        'channel_id' => [],
        'allow_cid'  => [],
        'allow_gid'  => []
    ];

    if ($channel_id) {
        $ch = q(
            "select channel_hash from channel where channel_id = %d",
            intval($channel_id)
        );
        if ($ch) {
            $ret['channel_id'][] = $ch[0]['channel_hash'];
        }
    }

    $groups = [];

    $x = q(
        "select * from xchan where xchan_hash = '%s'",
        dbesc($ob_hash)
    );

    if ($x) {
        // include xchans for all zot-like networks

        $xchans = q(
            "select xchan_hash, xchan_network from xchan where xchan_hash = '%s' OR ( xchan_guid = '%s' AND xchan_pubkey = '%s' ) ",
            dbesc($ob_hash),
            dbesc($x[0]['xchan_guid']),
            dbesc($x[0]['xchan_pubkey'])
        );

        if ($xchans) {
            $ret['allow_cid'] = ids_to_array($xchans, 'xchan_hash');
            $hashes = ids_to_querystr($xchans, 'xchan_hash', true);

            // physical groups this identity is a member of

            $r = q("SELECT hash FROM pgrp left join pgrp_member on pgrp.id = pgrp_member.gid WHERE xchan in ( " . protect_sprintf($hashes) . " ) ");
            if ($r) {
                foreach ($r as $rv) {
                    $groups[] = $rv['hash'];
                }
            }

            // virtual groups this identity is a member of

            $r = q("select channel_hash from channel left join abook on channel_id = abook_channel where abook_xchan in ( " . protect_sprintf($hashes) . " ) and abook_self = 0 and abook_pending = 0 and abook_archived = 0 ");
            if ($r) {
                foreach ($r as $rv) {
                    $groups[] = 'connections:' . $rv['channel_hash'];
                    if ($xchans[0]['xchan_network'] === 'nomad') {
                        $groups[] = 'nomad:' . $rv['channel_hash'];
                    }
					if ($xchans[0]['xchan_network'] === 'zot6') {
                        $groups[] = 'zot:' . $rv['channel_hash'];
                    }
                    if (in_array($xchans[0]['xchan_network'], ['activitypub', 'apnomadic'])) {
                        $groups[] = 'activitypub:' . $rv['channel_hash'];
                    }
                }
            }

            $ret['allow_gid'] = $groups;
        }
    }

    return $ret;
}