auth.js

/**
*  vim:set sw=2 ts=2 sts=2 ft=javascript expandtab:
*
*  # Authentification Module
*
*  ## License
*
*  Licensed to the Apache Software Foundation (ASF) under one
*  or more contributor license agreements.  See the NOTICE file
*  distributed with this work for additional information
*  regarding copyright ownership.  The ASF licenses this file
*  to you under the Apache License, Version 2.0 (the
*  "License"); you may not use this file except in compliance
*  with the License.  You may obtain a copy of the License at
*
*    http://www.apache.org/licenses/LICENSE-2.0
*
*  Unless required by applicable law or agreed to in writing,
*  software distributed under the License is distributed on an
*  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
*  KIND, either express or implied.  See the License for the
*  specific language governing permissions and limitations
*  under the License.
*
*  ## Description
*
*  This module contains all functions about authentification of MyPads users.
*  It's mainly based upon the excellent *passport* and *jsonwebtoken* Node
*  libraries.
*
*  TODO: abstract passport.authenticate to allow more easily custom errors
*/

// External dependencies
var ld         = require('lodash');
var jwt        = require('jsonwebtoken');
var ExtractJwt = require('passport-jwt').ExtractJwt;
var LdapAuth   = require('ldapauth-fork');
var CasAuth    = require('simple-cas-interface');
var settings;
try {
  // Normal case : when installed as a plugin
  settings = require('ep_etherpad-lite/node/utils/Settings');
}
catch (e) {
  if (process.env.TEST_LDAP) {
    settings = {
      'users': {
        'admin': {
          'password': 'admin',
          'is_admin': true
        },
        'parker': {
          'password': 'lovesKubiak',
          'is_admin': false
        }
      },
      'ep_mypads': {
        'ldap': {
          'url': 'ldap://rroemhild-test-openldap',
          'bindDN': 'cn=admin,dc=planetexpress,dc=com',
          'bindCredentials': 'GoodNewsEveryone',
          'searchBase': 'ou=people,dc=planetexpress,dc=com',
          'searchFilter': '(uid={{username}})',
          'properties': {
            'login': 'uid',
            'email': 'mail',
            'firstname': 'givenName',
            'lastname': 'sn'
          },
          'defaultLang': 'fr'
        }
      }
    };
  } else {
    // Testing case : we need to mock the express dependency
    settings = {
      users: {
        admin: { password: 'admin', is_admin: true },
        grace: { password: 'admin', is_admin: true },
        parker: { password: 'lovesKubiak', is_admin: false }
      }
    };
  }
}
var passport    = require('passport');
var JWTStrategy = require('passport-jwt').Strategy;
var cuid        = require('cuid');

// Local dependencies
var common = require('./model/common.js');
var user   = require('./model/user.js');
var conf   = require('./configuration.js');

var NOT_INTERNAL_AUTH_PWD = 'soooooo_useless';

module.exports = (function () {
  'use strict';

  /**
  * ## Authentification
  *
  * - `tokens` holds all actives tokens with user logins as key and user data
  *   as value, plus a special `key` attribute to check validity
  * - `secret` is the temporary random string key. It will be reinitialized
  *   after server relaunch, invaliditing all active users
  */

  var auth = {
    tokens: {},
    adminTokens: {},
    secret: cuid() // secret per etherpad session
  };

  /**
  * ## Internal functions
  *
  * These functions are not private like with closures, for testing purposes,
  * but they are expected be used only internally by other MyPads functions.
  */

  auth.fn = {};

  /**
  * ### getUser
  *
  * `getUser` is a synchronous function that checks if the given encrypted
  * `token` is valid, ie if login has been already found in local cache and if
  * the given key is the same as the generated one.
  * It returns the *user* object in case of success and *false* otherwise.
  *
  * TODO: unit test missing
  */

  auth.fn.getUser = function (token) {
    var jwt_payload = jwt.decode(token, auth.secret);
    if (!jwt_payload) { return false; }
    var login    = jwt_payload.login;
    var userAuth = (login && auth.tokens[login]);
    if (userAuth && (auth.tokens[login].key === jwt_payload.key)) {
      return auth.tokens[login];
    } else {
      return false;
    }
  };

  /**
  * ### local
  *
  * `local` is a synchronous function used to set up JWT strategy.
  */

  auth.fn.local = function () {
    var opts = {
      secretOrKey: auth.secret,
      passReqToCallback: true,
      jwtFromRequest: ExtractJwt.fromExtractors([
        ExtractJwt.fromUrlQueryParameter('auth_token'),
        ExtractJwt.fromBodyField('auth_token'),
        ExtractJwt.fromAuthHeaderWithScheme('JWT')
      ])
    };
    passport.use(new JWTStrategy(opts,
      function (req, jwt_payload, callback) {
        var isFS = function (s) { return (ld.isString(s) && !ld.isEmpty(s)); };
        if (!isFS(jwt_payload.login)) {
          throw new TypeError('BACKEND.ERROR.TYPE.LOGIN_STR');
        }
        if (!ld.isFunction(callback)) {
          throw new TypeError('BACKEND.ERROR.TYPE.CALLBACK_FN');
        }
        auth.fn.JWTFn(req, jwt_payload, false, callback);
      }
    ));
  };

  /**
  * ### checkMyPadsUser
  *
  * `checkMyPadsUser` checks user existence from given `login` and `pass`. It
  * uses the last argument, `callback` function, to return an *error* or *null*
  * and the *user* object.
  */

  auth.fn.checkMyPadsUser = function (login, pass, callback) {
    switch (conf.get('authMethod')) {
      case 'ldap':
        // ld.cloneDeep because LdapAuth would otherwise modify authLdapSettings conf
        var ldapConf = ld.cloneDeep(conf.get('authLdapSettings'));
        var lauth    = new LdapAuth(ldapConf);
        lauth.authenticate(login, pass, function(err, ldapuser) {
          lauth.close(function(error) {
            if (error) { console.error(error); }
          });
          if (err) {
            var emsg = err;
            // openldap error message || active directory error message
            if (ld.isString(err.lde_message) &&
                (err.lde_message === 'Invalid Credentials' ||
                  err.lde_message.match(/data 52e,/))
            ) {
              emsg = 'BACKEND.ERROR.AUTHENTICATION.PASSWORD_INCORRECT';
            } else if (
                (ld.isString(err) && err.match(/no such user/)) ||
                (ld.isString(err.lde_message) &&
                  (err.lde_message.match(/no such user/) ||
                    err.lde_message.match(/data 525,/)))
            ) {
              emsg = 'BACKEND.ERROR.USER.NOT_FOUND';
            } else {
              console.error('LdapAuth error: ', err);
            }
            return callback(new Error(emsg), false);
          }
          user.get(login, function(err, u) {
            var props = ldapConf.properties;
            var mail;
            if (Array.isArray(ldapuser[props.email])) {
              if (ldapuser[props.email].length > 0) {
                mail = ldapuser[props.email][0];
              } else {
                console.error('Ldap error: ldapuser[props.email] is an empty array');
              }
            } else if (ldapuser[props.email]) {
              mail = ldapuser[props.email];
            }
            if (!ld.isEmail(mail)) {
              emsg = 'BACKEND.ERROR.AUTHENTICATION.LDAP_NO_VALID_MAIL';
              return callback(new Error(emsg), false);
            }
            if (err) {
              // We have to create the user in mypads database
              ldapConf  = conf.get('authLdapSettings');
              user.set({
                  login: ldapuser[props.login],
                  password: NOT_INTERNAL_AUTH_PWD,
                  firstname: ldapuser[props.firstname],
                  lastname: ldapuser[props.lastname],
                  email: mail,
                  lang: ldapConf.defaultLang || 'en'
                }, callback);
            } else if (u.email     !== mail                      ||
                       u.firstname !== ldapuser[props.firstname] ||
                       u.lastname  !== ldapuser[props.lastname]) {
                // Update database and cache informations if needed
                // (i.e. update from LDAP)
                u.email     = mail;
                u.firstname = ldapuser[props.firstname];
                u.lastname  = ldapuser[props.lastname];
                u.password  = NOT_INTERNAL_AUTH_PWD;
                user.set(u, callback);
            } else {
              return callback(null, u);
            }
          });
        });
        break;
      case 'cas':
        user.get(login.login, function(err, u) {
          // If the user does not exist, we create the user
          if (err) {
            user.set(login, callback);
          } else {
            return callback(null, u);
          }
        });
        break;
      default:
        /* Prevents to use default external auth password if configuration has been changed
         * and now use internal authentification
         */
        if (pass === NOT_INTERNAL_AUTH_PWD) {
          var emsg = 'BACKEND.ERROR.AUTHENTICATION.PLEASE_CHANGE_YOUR_PASSWORD';
          return callback(new Error(emsg), false);
        }
        user.get(login, function (err, u) {
          if (err) { return callback(err); }
          auth.fn.isPasswordValid(u, pass, function (err, isValid) {
            if (err) { return callback(err); }
            if (!isValid) {
              var emsg = 'BACKEND.ERROR.AUTHENTICATION.PASSWORD_INCORRECT';
              return callback(new Error(emsg), false);
            }
            return callback(null, u);
          });
        });
      }
  };

  /**
  * ### checkAdminUser
  *
  * `checkAdminUser` checks admin existence from given `login` and `pass`. It
  * uses the last argument, `callback` function, to return an *error* or *null*
  * and the *user* object.
  */

  auth.fn.checkAdminUser = function (login, pass, callback) {
    if (!settings || !settings.users || !settings.users[login]) {
      return callback(new Error('BACKEND.ERROR.USER.NOT_FOUND'), null);
    }
    var u   = settings.users[login];
    u.login = login;
    var emsg;
    if (pass !== u.password) {
      emsg = 'BACKEND.ERROR.AUTHENTICATION.PASSWORD_INCORRECT';
      return callback(new Error(emsg, false));
    }
    if (!u.is_admin) {
      emsg = 'BACKEND.ERROR.AUTHENTICATION.ADMIN';
      return callback(new Error(emsg, false));
    }
    return callback(null, u);
  };

  /*
   * ### casAuth
   *
   * `casAuth` checks that the given CAS ticket is valid. It uses the last
   * argument, `callback` function, to return an *error* or *null* and the *user*
   * object.
   */
  var rgx = new RegExp('api/auth/login/cas$');
  auth.fn.casAuth = function (req, res, callback) {
    var ticket = req.body.ticket;
    if (ticket) {
      var acs         = ld.cloneDeep(conf.get('authCasSettings'));
      var props       = acs.properties;
      var defaultLang = acs.defaultLang;
      delete acs.properties;
      delete acs.defaultLang;
      var host = req.hostname || req.host;
      acs.serviceUrl = req.protocol+'://'+host+req.path.replace(rgx, '?/login');
      var cas = new CasAuth(acs);
      cas.validateServiceTicket(ticket)
        .then(function(info) {
          console.debug('mypads:casAuth - The ticket %s validation provided user informations ', ticket, info);  
          return callback(null, {
            login: info.attributes[props.login] || info[props.login],
            password: NOT_INTERNAL_AUTH_PWD,
            firstname: info.attributes[props.firstname],
            lastname: info.attributes[props.lastname],
            email: info.attributes[props.email],
            lang: defaultLang || 'en'
          });
        })
        .catch(function(err) {
          console.error(err);
          return callback(new Error(err));
        });
    } else {
      callback(new Error('BACKEND.ERROR.AUTHENTICATION.CAS_NO_TICKET'));
    }
  };

  /**
  * ### JWTFn
  *
  * `JWTFn` is the function used by JWT strategy for verifying if used
  * encrypted jwt token is correct. It takes:
  *
  * - the `req` Express request object, automatically populated from the
  *   strategy
  * - the JWT decoded token `jwt_payload` object
  * - a `admin` boolean
  * - a `callback` function, returning
  *   - *Error* if there is a problem
  *   - *null*, *false* and an object for auth error
  *   - *null* and the *user* or *token* object for auth success
  *
  *  TODO: expiration handling?
  */

  auth.fn.JWTFn = function (req, jwt_payload, admin, callback) {
    var checkFn = (admin ? auth.fn.checkAdminUser : auth.fn.checkMyPadsUser);
    var ns      = (admin ? 'adminTokens' : 'tokens');
    var login   = jwt_payload.login;
    var token   = auth[ns][login];
    if (!token || !jwt_payload.key) {
      var pass = jwt_payload.password;
      if (!ld.isString(pass)) {
        return callback(new Error('BACKEND.ERROR.TYPE.PASSWORD_STR'));
      }
      if (conf.get('authMethod') === 'cas' && !admin) {
        login = jwt_payload;
      }
      checkFn(login, pass, function (err, u) {
        if (err) { return callback(err, u); }
        auth[ns][u.login]     = u;
        auth[ns][u.login].key = cuid();
        return callback(null, u);
      });
    } else {
      if (token.key !== jwt_payload.key) {
        var emsg = 'BACKEND.ERROR.AUTHENTICATION.NOT_AUTH';
        return callback(new Error(emsg), false);
      }
      req.mypadsLogin = login;
      callback(null, token);
    }
  };

  /**
  * ### localFn
  *
  * `localFn` is a function that checks if login and password are correct. It
  * takes :
  *
  * - a `login` string
  * - a `password` string
  * - a `callback` function, returning
  *   - *Error* if there is a problem
  *   - *null*, *false* and an object for auth error
  *   - *null* and the *user* object for auth success
  */

  auth.fn.localFn = function (login, password, callback) {
    user.get(login, function (err, u) {
      if (err) { return callback(err); }
      auth.fn.isPasswordValid(u, password, function (err, isValid) {
        if (err) { return callback(err); }
        if (!isValid) {
          var emsg = 'BACKEND.ERROR.AUTHENTICATION.PASSWORD_INCORRECT';
          callback(new Error(emsg), false);
        } else {
          callback(null, u);
        }
      });
    });
  };

  /**
  * ### isPasswordValid
  *
  * `isPasswordValid` compares the hash of given password and saved salt with
  * the one saved in database.
  * It takes :
  *
  * - the `u` user object
  * - the `password` string
  * - a `callback` function, returning *Error* or *null* and a boolean
  */

  auth.fn.isPasswordValid = function (u, password, callback) {
    if (!ld.isString(password)) {
      return callback(new TypeError('BACKEND.ERROR.TYPE.PASSWORD_MISSING'));
    }
    // if u.visibility is defined, u is a group, which we shouldn't authenticate against LDAP
    if (conf.get('authMethod') === 'ldap' && ld.isUndefined(u.visibility)) {
      // ld.cloneDeep because LdapAuth would otherwise modify authLdapSettings conf
      var lauth = new LdapAuth(ld.cloneDeep(conf.get('authLdapSettings')));
      if (ld.isUndefined(u) || ld.isNull(u) || ld.isUndefined(u.login) || ld.isNull(u.login)) {
        return callback(null, false);
      } else {
        lauth.authenticate(u.login, password, function(err) {
          lauth.close(function(error) {
            if (error) { console.error(error); }
          });
          if (err) {
            if (err.lde_message === 'Invalid Credentials') {
              err = 'BACKEND.ERROR.AUTHENTICATION.PASSWORD_INCORRECT';
            } else if (err.match(/no such user/)) {
              err = 'BACKEND.ERROR.USER.NOT_FOUND';
            }
            console.error('LdapAuth error: ', err);
            return callback(null, false);
          }
          return callback(null, true);
        });
      }
    } else {
      common.hashPassword(u.password.salt, password, function (err, res) {
        if (err) { return callback(err); }
        callback(null, (res.hash === u.password.hash));
      });
    }
  };

  /**
  * ## Public functions
  *
  * ### init
  *
  * `init` is a synchronous function used to set up authentification. It :
  *
  * - initializes local strategy by default
  * - uses of passport middlwares for express
  * - launch session middleware bundled with express, using secret phrase saved
  *   in database
  * - mocks admin behavior if in testingMode
  */

  auth.init = function (app) {
    app.use(passport.initialize());
    auth.fn.local();
  };

  return auth;

}).call(this);