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friendica_2020-09-1_sharedH.../src/Util/Security.php

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PHP

<?php
/**
* @copyright Copyright (C) 2020, Friendica
*
* @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\Database\DBA;
use Friendica\Model\Contact;
use Friendica\Model\Group;
use Friendica\Model\User;
use Friendica\Core\Session;
/**
* Secures that User is allow to do requests
*/
class Security
{
public static function canWriteToUserWall($owner)
{
static $verified = 0;
if (!Session::isAuthenticated()) {
return false;
}
$uid = local_user();
if ($uid == $owner) {
return true;
}
if (local_user() && ($owner == 0)) {
return true;
}
if (!empty(Session::getRemoteContactID($owner))) {
// use remembered decision and avoid a DB lookup for each and every display item
// DO NOT use this function if there are going to be multiple owners
// We have a contact-id for an authenticated remote user, this block determines if the contact
// belongs to this page owner, and has the necessary permissions to post content
if ($verified === 2) {
return true;
} elseif ($verified === 1) {
return false;
} else {
$cid = Session::getRemoteContactID($owner);
if (!$cid) {
return false;
}
$r = q("SELECT `contact`.*, `user`.`page-flags` FROM `contact` INNER JOIN `user` on `user`.`uid` = `contact`.`uid`
WHERE `contact`.`uid` = %d AND `contact`.`id` = %d AND `contact`.`blocked` = 0 AND `contact`.`pending` = 0
AND `user`.`blockwall` = 0 AND `readonly` = 0 AND (`contact`.`rel` IN (%d , %d) OR `user`.`page-flags` = %d) LIMIT 1",
intval($owner),
intval($cid),
intval(Contact::SHARING),
intval(Contact::FRIEND),
intval(User::PAGE_FLAGS_COMMUNITY)
);
if (DBA::isResult($r)) {
$verified = 2;
return true;
} else {
$verified = 1;
}
}
}
return false;
}
/**
* Create a permission string for an element based on the visitor
*
* @param integer $owner_id User ID of the owner of the element
* @param boolean $accessible Should the element be accessible anyway?
* @return string SQL permissions
*/
public static function getPermissionsSQLByUserId(int $owner_id, bool $accessible = false)
{
$local_user = local_user();
$remote_contact = Session::getRemoteContactID($owner_id);
$acc_sql = '';
if ($accessible) {
$acc_sql = ' OR `accessible`';
}
/*
* Construct permissions
*
* default permissions - anonymous user
*/
$sql = " AND (allow_cid = ''
AND allow_gid = ''
AND deny_cid = ''
AND deny_gid = ''" . $acc_sql . ") ";
/*
* Profile owner - everything is visible
*/
if ($local_user && $local_user == $owner_id) {
$sql = '';
/*
* Authenticated visitor. Load the groups the visitor belongs to.
*/
} elseif ($remote_contact) {
$gs = '<<>>'; // should be impossible to match
$groups = Group::getIdsByContactId($remote_contact);
if (is_array($groups)) {
foreach ($groups as $g) {
$gs .= '|<' . intval($g) . '>';
}
}
$sql = sprintf(
" AND (NOT (deny_cid REGEXP '<%d>' OR deny_gid REGEXP '%s')
AND (allow_cid REGEXP '<%d>' OR allow_gid REGEXP '%s'
OR (allow_cid = '' AND allow_gid = ''))" . $acc_sql . ") ",
intval($remote_contact),
DBA::escape($gs),
intval($remote_contact),
DBA::escape($gs)
);
}
return $sql;
}
}