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zulip/docs/production/authentication-methods.md

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Authentication methods

Zulip supports a wide variety of authentication methods. Some of them require configuration to set up.

To configure or disable authentication methods on your Zulip server, edit the AUTHENTICATION_BACKENDS setting in /etc/zulip/settings.py, as well as any additional configuration your chosen authentication methods require; then restart the Zulip server.

Details on each method below.

Email and password

The EmailAuthBackend method is the one method enabled by default, and it requires no additional configuration.

Users set a password with the Zulip server, and log in with their email and password.

When first setting up your Zulip server, this method must be used for creating the initial realm and user. You can disable it after that.

Plug-and-play SSO (Google, GitHub)

With just a few lines of configuration, your Zulip server can authenticate users with any of several single-sign-on (SSO) authentication providers:

  • Google accounts, with GoogleAuthBackend
  • GitHub accounts, with GitHubAuthBackend
  • Microsoft Azure Active Directory, with AzureADAuthBackend

Each of these requires one to a handful of lines of configuration in settings.py, as well as a secret in zulip-secrets.conf. Details are documented in your settings.py.

.. _ldap:

LDAP (including Active Directory)

Zulip supports retrieving information about users via LDAP, and optionally using LDAP as an authentication mechanism.

In either configuration, you will need to do the following:

  1. Create your organization and first administrator account using another authentication backend (usually EmailAuthBackend). LDAP authentication does not support organization creation at this time; but you can disable EmailAuthBackend once you have created the organization.

  2. Tell Zulip how to connect to your LDAP server:

    • Fill out the section of your /etc/zulip/settings.py headed "LDAP integration, part 1: Connecting to the LDAP server".
    • If a password is required, put it in /etc/zulip/zulip-secrets.conf by setting auth_ldap_bind_password. For example: auth_ldap_bind_password = abcd1234.

  3. Decide how you want to map the information in your LDAP database to users' account data in Zulip. For each Zulip user, two closely related concepts are:

    • their email address. Zulip needs this in order to send, for example, a notification when they're offline and another user sends a PM.
    • their Zulip username. This means the name the user types into the Zulip login form. You might choose for this to be the user's email address (sam@example.com), or look like a traditional "username" (sam), or be something else entirely, depending on your environment.

    Either or both of these might be an attribute of the user records in your LDAP database.

  4. Tell Zulip how to map the user information in your LDAP database to the form it needs for authentication. There are three supported ways to set up the username and/or email mapping:

    (A) Using email addresses as usernames, if LDAP has each user's email address. To do this, just set AUTH_LDAP_USER_SEARCH to query by email address.

    (B) Using LDAP usernames as Zulip usernames, with email addresses formed consistently like sam -> sam@example.com. To do this, set AUTH_LDAP_USER_SEARCH to query by LDAP username, and LDAP_APPEND_DOMAIN = "example.com".

    (C) Using LDAP usernames as Zulip usernames, with email addresses taken from some other attribute in LDAP (for example, email). To do this, set AUTH_LDAP_USER_SEARCH to query by LDAP username, and LDAP_EMAIL_ATTR = "email".

You can quickly test whether your configuration works by running:

/home/zulip/deployments/current/manage.py query_ldap username

from the root of your Zulip installation. If your configuration is working, that will output the full name for your user (and that user's email address, if it isn't the same as the "Zulip username").

Active Directory: For Active Directory, one typically sets AUTH_LDAP_USER_SEARCH to one of:

  • To access by Active Directory username: 
    AUTH_LDAP_USER_SEARCH = LDAPSearch("ou=users,dc=example,dc=com",
                                   ldap.SCOPE_SUBTREE, "(sAMAccountName=%(user)s)")
  • To access by Active Directory email address: 
    AUTH_LDAP_USER_SEARCH = LDAPSearch("ou=users,dc=example,dc=com",
                                   ldap.SCOPE_SUBTREE, "(mail=%(user)s)")

If you are using LDAP for authentication: you will need to enable the zproject.backends.ZulipLDAPAuthBackend auth backend, in AUTHENTICATION_BACKENDS in /etc/zulip/settings.py. After doing so (and as always restarting the Zulip server to ensure your settings changes take effect), you should be able to log into Zulip by entering your email address and LDAP password on the Zulip login form.

Synchronizing data

Zulip can automatically synchronize data declared in AUTH_LDAP_USER_ATTR_MAP from LDAP into Zulip, via the following management command:

/home/zulip/deployments/current/manage.py sync_ldap_user_data

This will sync the fields declared in AUTH_LDAP_USER_ATTR_MAP for all of your users.

We recommend running this command in a regular cron job, to pick up changes made on your LDAP server.

All of these data synchronization options have the same model:

  • New users will be populated automatically with the name/avatar/etc. from LDAP (as configured) on account creation.
  • The manage.py sync_ldap_user_data cron job will automatically update existing users with any changes that were made in LDAP.
  • You can easily test your configuration using manage.py query_ldap. Once you're happy with the configuration, remember to restart the Zulip server with /home/zulip/deployments/current/scripts/restart-server so that your configuration changes take effect.

When using this feature, you may also want to prevent users from changing their display name in the Zulip UI, since any such changes would be automatically overwritten on the sync run of manage.py sync_ldap_user_data.

Synchronizing avatars

Starting with Zulip 2.0, Zulip supports syncing LDAP / Active Directory profile pictures (usually available in the thumbnailPhoto or jpegPhoto attribute in LDAP) by configuring the avatar key in AUTH_LDAP_USER_ATTR_MAP.

Synchronizing custom profile fields

Starting with Zulip 2.0, Zulip supports syncing custom profile fields from LDAP / Active Directory. To configure this, you first need to configure some custom profile fields for your Zulip organization. Then, define a mapping from the fields you'd like to sync from LDAP to the corresponding LDAP attributes. For example, if you have a custom profile field LinkedIn Profile and the corresponding LDAP attribute is linkedinProfile then you just need to add 'custom_profile_field__linkedin_profile': 'linkedinProfile' to the AUTH_LDAP_USER_ATTR_MAP.

Automatically deactivating users with Active Directory

Starting with Zulip 2.0, Zulip supports synchronizing the disabled/deactivated status of users from Active Directory. You can configure this by uncommenting the sample line "userAccountControl": "userAccountControl", in AUTH_LDAP_USER_ATTR_MAP (and restarting the Zulip server). Zulip will then treat users that are disabled via the "Disable Account" feature in Active Directory as deactivated in Zulip.

Users disabled in active directory will be immediately unable to login to Zulip, since Zulip queries the LDAP/Active Directory server on every login attempt. The user will be fully deactivated the next time your manage.py sync_ldap_user_data cron job runs (at which point they will be forcefully logged out from all active browser sessions, appear as deactivated in the Zulip UI, etc.).

This feature works by checking for the ACCOUNTDISABLE flag on the userAccountControl field in Active Directory. See this handy resource for details on the various userAccountControl flags.

Deactivating non-matching users

Starting with Zulip 2.0, Zulip supports automatically deactivating users if they are not found by the AUTH_LDAP_USER_SEARCH query (either because the user is no longer in LDAP/Active Directory, or because the user no longer matches the query). This feature is enabled by default if LDAP is the only authentication backend configured on the Zulip server. Otherwise, you can enable this feature by setting LDAP_DEACTIVATE_NON_MATCHING_USERS to True in /etc/zulip/settings.py. Nonmatching users will be fully deactivated the next time your manage.py sync_ldap_user_data cron job runs.

Other fields

Other fields you may want to sync from LDAP include:

  • Boolean flags; is_realm_admin (the organization's administrator permission) is the main one. You can use the AUTH_LDAP_USER_FLAGS_BY_GROUP feature of django-auth-ldap to configure a group to get this permissions. (We don't recommend using this flags feature for managing is_active because deactivating a user this way would not disable any active sessions the user might have; see the above discussion of automatic deactivation for how to do that properly).
  • String fields like default_language (e.g. en) or timezone, if you have that data in the right format in your LDAP database.
  • Coming soon: Support for syncing custom profile fields from your LDAP database.

You can look at the full list of fields in the Zulip user model; search for class UserProfile, but the above should cover all the fields that would be useful to sync from your LDAP databases.

Multiple LDAP searches

To do the union of multiple LDAP searches, use LDAPSearchUnion. For example:

AUTH_LDAP_USER_SEARCH = LDAPSearchUnion(
    LDAPSearch("ou=users,dc=example,dc=com", ldap.SCOPE_SUBTREE, "(uid=%(user)s)"),
    LDAPSearch("ou=otherusers,dc=example,dc=com", ldap.SCOPE_SUBTREE, "(uid=%(user)s)"),
)

Restricting access to an LDAP group

You can restrict access to your Zulip server to a set of LDAP groups using the AUTH_LDAP_REQUIRE_GROUP and AUTH_LDAP_DENY_GROUP settings in /etc/zulip/settings.py. See the upstream django-auth-ldap documentation for details.

Apache-based SSO with REMOTE_USER

If you have any existing SSO solution where a preferred way to deploy it (a) runs inside Apache, and (b) sets the REMOTE_USER environment variable, then the ZulipRemoteUserBackend method provides you with a straightforward way to deploy that SSO solution with Zulip.

Setup instructions for Apache-based SSO

  1. In /etc/zulip/settings.py, configure two settings:

    • AUTHENTICATION_BACKENDS: 'zproject.backends.ZulipRemoteUserBackend', and no other entries.

    • SSO_APPEND_DOMAIN: see documentation in settings.py.

    Make sure that you've restarted the Zulip server since making this configuration change.

  2. Edit /etc/zulip/zulip.conf and change the puppet_classes line to read:

    puppet_classes = zulip::voyager, zulip::apache_sso

  3. As root, run /home/zulip/deployments/current/scripts/zulip-puppet-apply to install our SSO integration.

  4. To configure our SSO integration, edit a copy of /etc/apache2/sites-available/zulip-sso.example, saving the result as /etc/apache2/sites-available/zulip-sso.conf. The example sets up HTTP basic auth, with an htpasswd file; you'll want to replace that with configuration for your SSO solution to authenticate the user and set REMOTE_USER.

    For testing, you may want to move ahead with the rest of the setup using the htpasswd example configuration and demonstrate that working end-to-end, before returning later to configure your SSO solution. You can do that with the following steps:

    /home/zulip/deployments/current/scripts/restart-server
cd /etc/apache2/sites-available/
cp zulip-sso.example zulip-sso.conf
htpasswd -c /home/zulip/zpasswd username@example.com # prompts for a password

  5. Run a2ensite zulip-sso to enable the SSO integration within Apache.

  6. Run service apache2 reload to use your new configuration. If Apache isn't already running, you may need to run service apache2 start instead.

Now you should be able to visit your Zulip server in a browser (e.g., at https://zulip.example.com/) and log in via the SSO solution.

Troubleshooting Apache-based SSO

Most issues with this setup tend to be subtle issues with the hostname/DNS side of the configuration. Suggestions for how to improve this SSO setup documentation are very welcome!

  • For example, common issues have to do with /etc/hosts not mapping settings.EXTERNAL_HOST to the Apache listening on 127.0.0.1/localhost.

  • While debugging, it can often help to temporarily change the Apache config in /etc/apache2/sites-available/zulip-sso to listen on all interfaces rather than just 127.0.0.1.

  • While debugging, it can also be helpful to change proxy_pass in /etc/nginx/zulip-include/app.d/external-sso.conf to point to a more explicit URL, possibly not over HTTPS.

  • The following log files can be helpful when debugging this setup:

    • /var/log/zulip/{errors.log,server.log} (the usual places)
    • /var/log/nginx/access.log (nginx access logs)
    • /var/log/apache2/zulip_auth_access.log (from the zulip-sso.conf Apache config file; you may want to change LogLevel in that file to "debug" to make this more verbose)

Life of an Apache-based SSO login attempt

Here's a summary of how the Apache REMOTE_USER SSO system works, assuming you're using the example configuration with HTTP basic auth. This summary should help with understanding what's going on as you try to debug.

  • Since you've configured /etc/zulip/settings.py to only define the zproject.backends.ZulipRemoteUserBackend, zproject/settings.py configures /accounts/login/sso/ as HOME_NOT_LOGGED_IN. This makes https://zulip.example.com/ (a.k.a. the homepage for the main Zulip Django app running behind nginx) redirect to /accounts/login/sso/ for a user that isn't logged in.

  • nginx proxies requests to /accounts/login/sso/ to an Apache instance listening on localhost:8888, via the config in /etc/nginx/zulip-include/app.d/external-sso.conf (using the upstream localhost_sso, defined in /etc/nginx/zulip-include/upstreams).

  • The Apache zulip-sso site which you've enabled listens on localhost:8888 and (in the example config) presents the htpasswd dialogue. (In a real configuration, it takes the user through whatever more complex interaction your SSO solution performs.) The user provides correct login information, and the request reaches a second Zulip Django app instance, running behind Apache, with REMOTE_USER set. That request is served by zerver.views.remote_user_sso, which just checks the REMOTE_USER variable and either logs the user in or, if they don't have an account already, registers them. The login sets a cookie.

  • After succeeding, that redirects the user back to / on port 443. This request is sent by nginx to the main Zulip Django app, which sees the cookie, treats them as logged in, and proceeds to serve them the main app page normally.

Adding more authentication backends

Adding an integration with any of the more than 100 authentication providers supported by python-social-auth (e.g., Facebook, Twitter, etc.) is easy to do if you're willing to write a bit of code, and pull requests to add new backends are welcome.

For example, the Azure Active Directory integration was about 30 lines of code, plus some documentation and an automatically generated migration. We also have helpful developer documentation on testing auth backends.

Development only

The DevAuthBackend method is used only in development, to allow passwordless login as any user in a development environment. It's mentioned on this page only for completeness.