owncloud/core

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apps/dav/lib/Connector/Sabre/Auth.php

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<?php
/**
 * @author Arthur Schiwon <blizzz@arthur-schiwon.de>
 * @author Bart Visscher <bartv@thisnet.nl>
 * @author Christoph Wurst <christoph@owncloud.com>
 * @author Jakob Sack <mail@jakobsack.de>
 * @author Lukas Reschke <lukas@statuscode.ch>
 * @author Markus Goetz <markus@woboq.com>
 * @author Michael Gapczynski <GapczynskiM@gmail.com>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 * @author Vincent Petry <pvince81@owncloud.com>
 *
 * @copyright Copyright (c) 2018, ownCloud GmbH
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * 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, version 3,
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */
namespace OCA\DAV\Connector\Sabre;

use OC\AppFramework\Http\Request;
use OC\Authentication\Exceptions\PasswordLoginForbiddenException;
use OC\Authentication\TwoFactorAuth\Manager;
use OC\Authentication\AccountModule\Manager as AccountModuleManager;
use OC\Security\SignedUrl\Verifier;
use OC\User\LoginException;
use OC\User\Session;
use OCA\DAV\Connector\Sabre\Exception\PasswordLoginForbidden;
use OCP\Authentication\Exceptions\AccountCheckException;
use OCP\IConfig;
use OCP\IRequest;
use OCP\ISession;
use Sabre\DAV\Auth\Backend\AbstractBasic;
use Sabre\DAV\Exception\NotAuthenticated;
use Sabre\DAV\Exception\ServiceUnavailable;
use Sabre\HTTP\RequestInterface;
use Sabre\HTTP\ResponseInterface;

class Auth extends AbstractBasic {
    public const DAV_AUTHENTICATED = 'AUTHENTICATED_TO_DAV_BACKEND';

    /** @var ISession */
    private $session;
    /** @var Session */
    private $userSession;
    /** @var IRequest */
    private $request;
    /** @var Manager */
    private $twoFactorManager;
    /** @var AccountModuleManager */
    private $accountModuleManager;
    /**
     * @var IConfig
     */
    private $config;

    /**
     * @param ISession $session
     * @param Session $userSession
     * @param IRequest $request
     * @param Manager $twoFactorManager
     * @param AccountModuleManager $accountModuleManager
     * @param IConfig $config
     * @param string $principalPrefix
     */
    public function __construct(
        ISession $session,
        Session $userSession,
        IRequest $request,
        Manager $twoFactorManager,
        AccountModuleManager $accountModuleManager,
        IConfig $config,
        $principalPrefix = 'principals/users/'
    ) {
        $this->session = $session;
        $this->userSession = $userSession;
        $this->twoFactorManager = $twoFactorManager;
        $this->accountModuleManager = $accountModuleManager;
        $this->request = $request;
        $this->principalPrefix = $principalPrefix;

        // setup realm
        $defaults = new \OC_Defaults();
        $this->realm = $defaults->getName();
        $this->config = $config;
    }

    /**
     * Whether the user has initially authenticated via DAV
     *
     * This is required for WebDAV clients that resent the cookies even when the
     * account was changed.
     *
     * @see https://github.com/owncloud/core/issues/13245
     *
     * @param string $username
     * @return bool
     */
    public function isDavAuthenticated($username) {
        return $this->session->get(self::DAV_AUTHENTICATED) !== null &&
        $this->session->get(self::DAV_AUTHENTICATED) === $username;
    }

    /**
     * Validates a username and password
     *
     * This method should return true or false depending on if login
     * succeeded.
     *
     * @param string $username
     * @param string $password
     * @return bool
     */
    protected function validateUserPass($username, $password) {
        if (\trim($username) === '') {
            return false;
        }
        if ($this->userSession->isLoggedIn() &&
            $this->userSession->verifyAuthHeaders($this->request) &&
            $this->isDavAuthenticated($this->userSession->getUser()->getUID())
        ) {
            \OC_Util::setupFS($this->userSession->getUser()->getUID());
            $this->session->close();
            return true;
        } else {
            \OC_Util::setupFS(); //login hooks may need early access to the filesystem
            try {
                if ($this->userSession->logClientIn($username, $password, $this->request)) {
                    \OC_Util::setupFS($this->userSession->getUser()->getUID());
                    $this->session->set(self::DAV_AUTHENTICATED, $this->userSession->getUser()->getUID());
                    $this->session->close();
                    return true;
                } else {
                    $this->session->close();
                    return false;
                }
            } catch (PasswordLoginForbiddenException $ex) {
                $this->session->close();
                throw new PasswordLoginForbidden();
            }
        }
    }

    /**
     * @param RequestInterface $request
     * @param ResponseInterface $response
     * @return array
     * @throws NotAuthenticated
     * @throws ServiceUnavailable
     */
    public function check(RequestInterface $request, ResponseInterface $response) {
        try {
            return $this->auth($request, $response);
        } catch (LoginException $e) {
            throw new NotAuthenticated($e->getMessage(), $e->getCode(), $e);
        } catch (NotAuthenticated $e) {
            throw $e;
        } catch (\Exception $e) {
            $class = \get_class($e);
            $msg = $e->getMessage();
            throw new ServiceUnavailable("$class: $msg");
        }
    }

    /**
     * Checks whether a CSRF check is required on the request
     *
     * @return bool
     */
    private function requiresCSRFCheck() {
        // If not POST no check is required
        if ($this->request->getMethod() !== 'POST') {
            return false;
        }

        // Official ownCloud clients require no checks
        if ($this->request->isUserAgent([
            Request::USER_AGENT_OWNCLOUD_DESKTOP,
            Request::USER_AGENT_OWNCLOUD_ANDROID,
            Request::USER_AGENT_OWNCLOUD_IOS,
        ])) {
            return false;
        }

        // If not logged-in no check is required
        if (!$this->userSession->isLoggedIn()) {
            return false;
        }

        // If logged-in AND DAV authenticated no check is required
        if ($this->userSession->isLoggedIn() &&
            $this->isDavAuthenticated($this->userSession->getUser()->getUID())) {
            return false;
        }

        return true;
    }

    /**
     * @param RequestInterface $request
     * @param ResponseInterface $response
     * @return array
     * @throws NotAuthenticated
     * @throws ServiceUnavailable
     * @throws LoginException
     */
    private function auth(RequestInterface $request, ResponseInterface $response) {
        $forcedLogout = false;
        if (!$this->request->passesCSRFCheck() &&
            $this->requiresCSRFCheck()) {
            // In case of a fail with POST we need to recheck the credentials
            $forcedLogout = true;
        }

        if ($forcedLogout) {
            $this->userSession->logout();
        } else {
            if ($this->twoFactorManager->needsSecondFactor()) {
                throw new NotAuthenticated('2FA challenge not passed.');
            }
            if (\OC_User::handleApacheAuth() ||
                //Fix for broken webdav clients
                ($this->userSession->isLoggedIn() && $this->session->get(self::DAV_AUTHENTICATED) === null) ||
                //Well behaved clients that only send the cookie are allowed
                ($this->userSession->isLoggedIn() && $this->session->get(self::DAV_AUTHENTICATED) === $this->userSession->getUser()->getUID() && ($request->getHeader('Authorization') === null || $request->getHeader('Authorization') === ''))
            ) {
                $user = $this->userSession->getUser();
                $this->checkAccountModule($user);
                $uid = $user->getUID();
                \OC_Util::setupFS($uid);
                $this->session->close();
                return [true, $this->principalPrefix . $uid];
            }
        }

        $data = parent::check($request, $response);
        if ($data[0] === true) {
            $user = $this->userSession->getUser();
            if ($user === null) {
                throw new \LogicException('Logged in but no user -> :boom:');
            }
            $this->checkAccountModule($user);
            $startPos = \strrpos($data[1], '/') + 1;
            $data[1] = \substr_replace($data[1], $user->getUID(), $startPos);
        }

        // signed url handling
        $verifier = new Verifier($request, $this->config);
        if ($verifier->isSignedRequest()) {
            if (!$verifier->signedRequestIsValid()) {
                return [false, 'Invalid url signature'];
            }
            // TODO: setup session ???
            $urlCredential = $verifier->getUrlCredential();
            $user = \OC::$server->getUserManager()->get($urlCredential);
            if ($user === null) {
                $message = \OC::$server->getL10N('dav')->t('User unknown');
                throw new LoginException($message);
            }
            if (!$user->isEnabled()) {
                $message = \OC::$server->getL10N('dav')->t('User disabled');
                throw new LoginException($message);
            }
            $this->userSession->setUser($user);
            \OC_Util::setupFS($urlCredential);
            $this->session->close();
            return [true, $this->principalPrefix . $urlCredential];
        }
        return $data;
    }

    /**
     * @param $user
     * @throws ServiceUnavailable
     */
    private function checkAccountModule($user): void {
        if ($user === null) {
            throw new \UnexpectedValueException('No user in session');
        }
        try {
            $this->accountModuleManager->check($user);
        } catch (AccountCheckException $ex) {
            throw new ServiceUnavailable($ex->getMessage(), $ex->getCode(), $ex);
        }
    }

    public function challenge(RequestInterface $request, ResponseInterface $response): void {
        $schema = 'Basic';
        // do not re-authenticate over ajax, use dummy auth name to prevent browser popup
        if (\in_array('XMLHttpRequest', \explode(',', $request->getHeader('X-Requested-With')), true)) {
            $schema = 'DummyBasic';
        }

        $response->addHeader('WWW-Authenticate', "$schema realm=\"{$this->realm}\", charset=\"UTF-8\"");
        $response->setStatus(401);
    }
}