class.ilLDAPQuery.php

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<?php

declare(strict_types=1);

class ilLDAPQuery
{
    public const LDAP_BIND_DEFAULT = 0;
    public const LDAP_BIND_ADMIN = 1;
    public const LDAP_BIND_TEST = 2;
    public const LDAP_BIND_AUTH = 10;

    private const IL_LDAP_SUPPORTED_CONTROL = 'supportedControl';
    private const PAGINATION_SIZE = 100;

    private string $ldap_server_url;
    private ilLDAPServer $settings;

    private ilLogger $logger;

    private ilLDAPAttributeMapping $mapping;

    private array $user_fields = [];
    private array $users = [];

    private $lh = false;

    public function __construct(ilLDAPServer $a_server, string $a_url = '')
    {
        global $DIC;
        $this->logger = $DIC->logger()->auth();

        $this->settings = $a_server;

        if ($a_url !== '') {
            $this->ldap_server_url = $a_url;
        } else {
            $this->ldap_server_url = $this->settings->getUrl();
        }

        $this->mapping = ilLDAPAttributeMapping::_getInstanceByServerId($this->settings->getServerId());

        $this->fetchUserProfileFields();
        $this->connect();
    }

    public function getServer(): ilLDAPServer
    {
        return $this->settings;
    }

    public function fetchUser(string $a_name): array
    {
        if (!$this->readUserData($a_name)) {
            return [];
        }

        return $this->users;
    }


    public function fetchUsers(): array
    {
        // First of all check if a group restriction is enabled
        // YES: => fetch all group members
        // No:  => fetch all users
        if ($this->settings->getGroupName() !== '') {
            $this->logger->debug('Searching for group members.');

            $groups = $this->settings->getGroupNames();
            if (count($groups) <= 1) {
                $this->fetchGroupMembers();
            } else {
                foreach ($groups as $group) {
                    $this->fetchGroupMembers($group);
                }
            }
        }
        if ($this->settings->getGroupName() === '' || $this->settings->isMembershipOptional()) {
            $this->logger->info('Start reading all users...');
            $this->readAllUsers();
            #throw new ilLDAPQueryException('LDAP: Called import of users without specifying group restrictions. NOT IMPLEMENTED YET!');
        }
        return $this->users;
    }

    public function query(string $a_search_base, string $a_filter, int $a_scope, array $a_attributes): ilLDAPResult
    {
        $res = $this->queryByScope($a_scope, $a_search_base, $a_filter, $a_attributes);
        if ($res === false) {
            throw new ilLDAPQueryException(__METHOD__ . ' ' . ldap_error($this->lh) . ' ' .
                sprintf(
                    'DN: %s, Filter: %s, Scope: %s',
                    $a_search_base,
                    $a_filter,
                    $a_scope
                ));
        }

        return (new ilLDAPResult($this->lh, $res))->run();
    }

    public function modAdd(string $a_dn, array $a_attribute): bool
    {
        if (ldap_mod_add($this->lh, $a_dn, $a_attribute)) {
            return true;
        }

        throw new ilLDAPQueryException(__METHOD__ . ' ' . ldap_error($this->lh));
    }

    public function modDelete(string $a_dn, array $a_attribute): bool
    {
        if (ldap_mod_del($this->lh, $a_dn, $a_attribute)) {
            return true;
        }
        throw new ilLDAPQueryException(__METHOD__ . ' ' . ldap_error($this->lh));
    }

    private function readAllUsers(): void
    {
        // Build search base
        $this->logger->debug($this->settings->getSearchBase());
        $this->logger->debug($this->settings->getBaseDN());
        if (($dn = $this->settings->getSearchBase()) && substr($dn, -1) !== ',') {
            $dn .= ',';
        }
        $dn .= $this->settings->getBaseDN();
        if ($this->checkPaginationEnabled()) {
            try {
                $tmp_result = $this->runReadAllUsersPaged($dn);
            } catch (ilLDAPPagingException $e) {
                $this->logger->warning('Using LDAP with paging failed. Trying to use fallback.');
                $tmp_result = $this->runReadAllUsersPartial($dn);
            }
        } else {
            $tmp_result = $this->runReadAllUsersPartial($dn);
        }

        if (!$tmp_result->numRows()) {
            $this->logger->notice('No users found. Aborting.');
        }
        $this->logger->info('Found ' . $tmp_result->numRows() . ' users.');
        $attribute = strtolower($this->settings->getUserAttribute());
        foreach ($tmp_result->getRows() as $data) {
            if (isset($data[$attribute]) && is_scalar($data[$attribute]) && (string) $data[$attribute] !== '') {
                $this->readUserData((string) $data[$attribute]);
                continue;
            }

            $this->logger->warning(sprintf(
                'Unknown error. No or invalid value found for attribute %s: %s',
                $this->settings->getUserAttribute(),
                var_export($data[$attribute] ?? null, true)
            ));
        }
        unset($tmp_result);
    }

    private function runReadAllUsersPaged(string $dn): ilLDAPResult
    {
        $filter = '(&' . $this->settings->getFilter();
        $filter .= ('(' . $this->settings->getUserAttribute() . '=*))');
        $this->logger->info('Searching with ldap search and filter ' . $filter . ' in ' . $dn);

        $tmp_result = new ilLDAPResult($this->lh);
        $cookie = '';
        $estimated_results = 0;
        do {
            // Setup our paged results control.
            $controls = [
                LDAP_CONTROL_PAGEDRESULTS => [
                    'oid' => LDAP_CONTROL_PAGEDRESULTS,
                    'isCritical' => true,
                    'value' => [
                        'size' => self::PAGINATION_SIZE,
                        'cookie' => $cookie,
                    ],
                ],
            ];
            $res = $this->queryByScope(
                $this->settings->getUserScope(),
                $dn,
                $filter,
                array($this->settings->getUserAttribute()),
                $controls
            );

            $tmp_result->setResult($res);
            $tmp_result->run();
            try {
                $errcode = 0;
                $matcheddn = '';
                $errmsg = '';
                $referrals = [];
                ldap_parse_result($this->lh, $res, $errcode, $matcheddn, $errmsg, $referrals, $controls);
                $cookie = $controls[LDAP_CONTROL_PAGEDRESULTS]['value']['cookie'] ?? '';
                $this->logger->debug('Estimated number of results: ' . $estimated_results);
            } catch (Exception $e) {
                $this->logger->warning('Result pagination failed with message: ' . $e->getMessage());
                throw new ilLDAPPagingException($e->getMessage());
            }
        } while (!empty($cookie));

        // finally reset cookie
        return $tmp_result;
    }

    private function runReadAllUsersPartial(string $dn): ilLDAPResult
    {
        $filter = $this->settings->getFilter();
        $page_filter = array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '-');
        $chars = array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z');
        $tmp_result = new ilLDAPResult($this->lh);

        foreach ($page_filter as $letter) {
            $new_filter = '(&';
            $new_filter .= $filter;

            if ($letter === '-') {
                $new_filter .= ('(!(|');
                foreach ($chars as $char) {
                    $new_filter .= ('(' . $this->settings->getUserAttribute() . '=' . $char . '*)');
                }
                $new_filter .= ')))';
            } else {
                $new_filter .= ('(' . $this->settings->getUserAttribute() . '=' . $letter . '*))');
            }

            $this->logger->info('Searching with ldap search and filter ' . $new_filter . ' in ' . $dn);
            $res = $this->queryByScope(
                $this->settings->getUserScope(),
                $dn,
                $new_filter,
                array($this->settings->getUserAttribute())
            );
            $tmp_result->setResult($res);
            $tmp_result->run();
        }

        return $tmp_result;
    }

    public function checkGroupMembership(string $a_ldap_user_name, array $ldap_user_data): bool
    {
        $group_names = $this->getServer()->getGroupNames();

        if (!count($group_names)) {
            $this->logger->debug('No LDAP group restrictions found');
            return true;
        }

        $group_dn = $this->getServer()->getGroupDN();
        if (
            $group_dn &&
            (substr($group_dn, -1) !== ',')
        ) {
            $group_dn .= ',';
        }
        $group_dn .= $this->getServer()->getBaseDN();

        foreach ($group_names as $group) {
            $user = $a_ldap_user_name;
            if ($this->getServer()->enabledGroupMemberIsDN()) {
                if ($this->getServer()->enabledEscapeDN()) {
                    $user = ldap_escape($ldap_user_data['dn'], "", LDAP_ESCAPE_FILTER);
                } else {
                    $user = $ldap_user_data['dn'];
                }
            }

            $filter = sprintf(
                '(&(%s=%s)(%s=%s)%s)',
                $this->getServer()->getGroupAttribute(),
                $group,
                $this->getServer()->getGroupMember(),
                $user,
                $this->getServer()->getGroupFilter()
            );
            $this->logger->debug('Current group search base: ' . $group_dn);
            $this->logger->debug('Current group filter: ' . $filter);

            $res = $this->queryByScope(
                $this->getServer()->getGroupScope(),
                $group_dn,
                $filter,
                [$this->getServer()->getGroupMember()]
            );

            $this->logger->dump($res);

            $tmp_result = new ilLDAPResult($this->lh, $res);
            $tmp_result->run();
            $group_result = $tmp_result->getRows();

            $this->logger->debug('Group query returned: ');
            $this->logger->dump($group_result, ilLogLevel::DEBUG);

            if (count($group_result)) {
                return true;
            }
        }

        // group restrictions failed check optional membership
        if ($this->getServer()->isMembershipOptional()) {
            $this->logger->debug('Group restrictions failed, checking user filter.');
            if ($this->readUserData($a_ldap_user_name, true, true)) {
                $this->logger->debug('User filter matches.');
                return true;
            }
        }
        $this->logger->debug('Group restrictions failed.');
        return false;
    }


    private function fetchGroupMembers(string $a_name = ''): void
    {
        $group_name = $a_name !== '' ? $a_name : $this->settings->getGroupName();

        // Build filter
        $filter = sprintf(
            '(&(%s=%s)%s)',
            $this->settings->getGroupAttribute(),
            $group_name,
            $this->settings->getGroupFilter()
        );


        // Build search base
        if (($gdn = $this->settings->getGroupDN()) && substr($gdn, -1) !== ',') {
            $gdn .= ',';
        }
        $gdn .= $this->settings->getBaseDN();

        $this->logger->debug('Using filter ' . $filter);
        $this->logger->debug('Using DN ' . $gdn);
        $res = $this->queryByScope(
            $this->settings->getGroupScope(),
            $gdn,
            $filter,
            array($this->settings->getGroupMember())
        );

        $tmp_result = new ilLDAPResult($this->lh, $res);
        $tmp_result->run();
        $group_data = $tmp_result->getRows();


        if (!$tmp_result->numRows()) {
            $this->logger->info('No group found.');
            return;
        }

        $readUserData = function (array $members): void {
            if ($members === []) {
                $this->logger->warning(sprintf(
                    'No valid member values found for group member attribute: %s',
                    $this->settings->getGroupMember()
                ));
                return;
            }

            foreach ($members as $member) {
                $this->readUserData($member, true, true);
            }
        };

        // All groups
        $attribute_name = strtolower($this->settings->getGroupMember());
        foreach ($group_data as $data) {
            $members = [];
            if (isset($data[$attribute_name])) {
                if (is_array($data[$attribute_name])) {
                    $members = array_map('strval', array_filter($data[$attribute_name]));
                    $this->logger->debug('Found ' . count($members) . ' group members for group ' . $data['dn']);
                } elseif (is_scalar($data[$attribute_name]) && (string) $data[$attribute_name] !== '') {
                    $members = [
                        (string) $data[$attribute_name]
                    ];
                }
            }

            $readUserData($members);
        }
        unset($tmp_result);
    }

    private function readUserData(string $a_name, bool $a_check_dn = false, bool $a_try_group_user_filter = false): bool
    {
        $filter = $this->settings->getFilter();
        if ($a_try_group_user_filter && $this->settings->isMembershipOptional()) {
            $filter = $this->settings->getGroupUserFilter();
        }

        // Build filter
        if ($a_check_dn && $this->settings->enabledGroupMemberIsDN()) {
            $dn = $a_name;

            $fields = array_merge($this->user_fields, array('useraccountcontrol'));
            $res = $this->queryByScope(ilLDAPServer::LDAP_SCOPE_BASE, strtolower($dn), $filter, $fields);
        } else {
            $filter = sprintf(
                '(&(%s=%s)%s)',
                $this->settings->getUserAttribute(),
                $a_name,
                $filter
            );

            // Build search base
            if (($dn = $this->settings->getSearchBase()) && substr($dn, -1) !== ',') {
                $dn .= ',';
            }
            $dn .= $this->settings->getBaseDN();
            $fields = array_merge($this->user_fields, array('useraccountcontrol'));
            $res = $this->queryByScope($this->settings->getUserScope(), strtolower($dn), $filter, $fields);
        }


        $tmp_result = new ilLDAPResult($this->lh, $res);
        $tmp_result->run();
        if (!$tmp_result->numRows()) {
            $this->logger->info('LDAP: No user data found for: ' . $a_name);
            unset($tmp_result);
            return false;
        }

        if ($user_data = $tmp_result->get()) {
            if (isset($user_data['useraccountcontrol']) && ($user_data['useraccountcontrol'] & 0x02)) {
                $this->logger->notice('LDAP: ' . $a_name . ' account disabled.');
                return false;
            }

            $account = $user_data[strtolower($this->settings->getUserAttribute())] ?? '';
            if (is_array($account)) {
                $account = array_shift($account) ?? '';
            }

            $user_ext = strtolower((string) $account);
            if ($user_ext === '') {
                $this->logger->notice('LDAP: Could not find user attribute ' . $this->settings->getUserAttribute() . '.');
                return false;
            }

            // auth mode depends on ldap server settings
            $auth_mode = $this->settings->getAuthenticationMappingKey();
            $user_data['ilInternalAccount'] = ilObjUser::_checkExternalAuthAccount($auth_mode, $user_ext);
            $this->users[$user_ext] = $user_data;
        }
        return true;
    }

    private function queryByScope(
        int $a_scope,
        string $a_base_dn,
        string $a_filter,
        array $a_attributes,
        array $controls = []
    ) {
        $a_filter = $a_filter ?: "(objectclass=*)";

        set_error_handler(static function (int $severity, string $message, string $file, int $line): void {
            throw new ErrorException($message, $severity, $severity, $file, $line);
        });

        $result = null; // We should ensure the similar behaviour of using the @ operator in PHP < 8.x

        try {
            switch ($a_scope) {
                case ilLDAPServer::LDAP_SCOPE_SUB:
                    $result = ldap_search(
                        $this->lh, $a_base_dn, $a_filter, $a_attributes, 0, 0, 0, LDAP_DEREF_NEVER, $controls
                    );
                    break;

                case ilLDAPServer::LDAP_SCOPE_ONE:
                    $result = ldap_list(
                        $this->lh, $a_base_dn, $a_filter, $a_attributes, 0, 0, 0, LDAP_DEREF_NEVER, $controls
                    );
                    break;

                case ilLDAPServer::LDAP_SCOPE_BASE:
                    $result = ldap_read(
                        $this->lh, $a_base_dn, $a_filter, $a_attributes, 0, 0, 0, LDAP_DEREF_NEVER, $controls
                    );
                    break;

                default:
                    throw new ilLDAPUndefinedScopeException(
                        "Undefined LDAP Search Scope: " . $a_scope
                    );
            }
        } catch (ErrorException $e) {
            $this->logger->warning($e->getMessage());
            $this->logger->warning($e->getTraceAsString());
        } finally {
            restore_error_handler();
        }

        $error = ldap_errno($this->lh);
        if ($error) {
            $this->logger->warning("LDAP Error Code: " . $error . "(" . ldap_err2str($error) . ")");
            $this->logger->warning('Base DN:' . $a_base_dn);
            $this->logger->warning('Filter: ' . $a_filter);
        }

        return $result;
    }

    private function connect(): void
    {
        $this->lh = ldap_connect($this->ldap_server_url);

        // LDAP Connect
        if (!$this->lh) {
            throw new ilLDAPQueryException("LDAP: Cannot connect to LDAP Server: " . $this->settings->getUrl());
        }
        // LDAP Version
        if (!ldap_set_option($this->lh, LDAP_OPT_PROTOCOL_VERSION, $this->settings->getVersion())) {
            throw new ilLDAPQueryException("LDAP: Cannot set version to: " . $this->settings->getVersion());
        }
        // Switch on referrals
        if ($this->settings->isActiveReferrer()) {
            if (!ldap_set_option($this->lh, LDAP_OPT_REFERRALS, true)) {
                throw new ilLDAPQueryException("LDAP: Cannot switch on LDAP referrals");
            }
        } else {
            ldap_set_option($this->lh, LDAP_OPT_REFERRALS, false);
            $this->logger->debug('Switching referrals to false.');
        }
        // Start TLS
        if ($this->settings->isActiveTLS() && !ldap_start_tls($this->lh)) {
            throw new ilLDAPQueryException("LDAP: Cannot start LDAP TLS");
        }
    }

    public function bind(int $a_binding_type = ilLDAPQuery::LDAP_BIND_DEFAULT, string $a_user_dn = '', string $a_password = ''): void
    {
        switch ($a_binding_type) {
            case self::LDAP_BIND_TEST:
                ldap_set_option($this->lh, LDAP_OPT_NETWORK_TIMEOUT, ilLDAPServer::DEFAULT_NETWORK_TIMEOUT);
                // fall through
                // no break
            case self::LDAP_BIND_DEFAULT:
                // Now bind anonymously or as user
                if (
                    ilLDAPServer::LDAP_BIND_USER === $this->settings->getBindingType() &&
                    $this->settings->getBindUser() !== ''
                ) {
                    $user = $this->settings->getBindUser();
                    $pass = $this->settings->getBindPassword();

                    $this->logger->debug('Bind as ' . $user);
                } else {
                    $user = $pass = '';
                    $this->logger->debug('Bind anonymous');
                }
                break;

            case self::LDAP_BIND_ADMIN:
                $user = $this->settings->getRoleBindDN();
                $pass = $this->settings->getRoleBindPassword();

                if ($user === '' || $pass === '') {
                    $user = $this->settings->getBindUser();
                    $pass = $this->settings->getBindPassword();
                }
                break;

            case self::LDAP_BIND_AUTH:
                $this->logger->debug('Trying to bind as: ' . $a_user_dn);
                $user = $a_user_dn;
                $pass = $a_password;
                break;


            default:
                throw new ilLDAPQueryException('LDAP: unknown binding type in: ' . __METHOD__);
        }

        try {
            set_error_handler(static function (int $severity, string $message, string $file, int $line): void {
                throw new ErrorException($message, $severity, $severity, $file, $line);
            });

            if (!ldap_bind($this->lh, $user, $pass)) {
                throw new ilLDAPQueryException('LDAP: Cannot bind as ' . $user . ' with message: ' . ldap_err2str(ldap_errno($this->lh)) . ' Trying fallback...', ldap_errno($this->lh));
            }
        } catch (Throwable $e) {
            throw new ilLDAPQueryException('LDAP: Cannot bind as ' . $user . ' with message: ' . $e->getMessage());
        } finally {
            restore_error_handler();
        }

        $this->logger->debug('Bind successful.');
    }

    private function fetchUserProfileFields(): void
    {
        $this->user_fields = array_merge(
            array($this->settings->getUserAttribute()),
            array('dn'),
            $this->mapping->getFields(),
            ilLDAPRoleAssignmentRules::getAttributeNames($this->getServer()->getServerId())
        );
    }

    public function __destruct()
    {
        if ($this->lh) {
            ldap_unbind($this->lh);
        }
    }

    public function checkPaginationEnabled(): bool
    {
        if ($this->getServer()->getVersion() !== 3) {
            $this->logger->info('Pagination control unavailable for ldap v' . $this->getServer()->getVersion());
            return false;
        }

        $result = ldap_read($this->lh, '', '(objectClass=*)', [self::IL_LDAP_SUPPORTED_CONTROL]);
        if ($result === false) {
            $this->logger->warning('Failed to query for pagination control');
            return false;
        }
        $entries = (array) (ldap_get_entries($this->lh, $result)[0] ?? []);
        if (
            array_key_exists(strtolower(self::IL_LDAP_SUPPORTED_CONTROL), $entries) &&
            is_array($entries[strtolower(self::IL_LDAP_SUPPORTED_CONTROL)]) &&
            in_array(LDAP_CONTROL_PAGEDRESULTS, $entries[strtolower(self::IL_LDAP_SUPPORTED_CONTROL)], true)
        ) {
            $this->logger->info('Using paged control');
            return true;
        }
        $this->logger->info('Paged control disabled');
        return false;
    }
}