.. only:: html


.. _authentication_overview:

Authentication System Overview
==============================

.. only:: html

   .. contents::
      :local:

.. _figure_authsystem:

.. figure:: img/auth-system-overview.png
   :align: center

   Anatomy of authentication system

Authentication database
-----------------------

The new authentication system stores authentication configurations in an SQLite
database file located, by default, at :file:`<user home>/.qgis3/qgis-auth.db`.

This authentication database can be moved between QGIS installations without
affecting other current QGIS user preferences, as it is completely separate from
normal QGIS settings. A configuration ID (a random 7-character alphanumeric
string) is generated when initially storing a configuration to the database.
This represents the configuration, thereby allowing the ID to be stored in plain
text application components, (such as project, plugin, or settings files)
without disclosure of its associated credentials.

.. note::

   The parent directory of the `qgis-auth.db` can be set using the following
   environment variable, ``QGIS_AUTH_DB_DIR_PATH``, or set on the command line
   during launch with the ``--authdbdirectory`` option.

Master password
---------------

To store or access sensitive information within the database, a user must define
a `master password`. A new master password is requested and verified when
initially storing any encrypted data to the database. Only when sensitive
information is accessed is the user prompted for the master password, which is
then cached for the remainder of the session (until application is quit), unless
the user manually chooses an action to clear its cached value. Some instances of
using the authentication system do not require input of the master password,
such as when selecting an existing authentication configuration, or applying a
configuration to a server configuration (such as when adding a WMS layer).

.. _figure_masterpass:

.. figure:: img/auth-password-new_enter.png
   :align: center

   Input new master password

.. note::

   A path to a file containing the master password can be set using the
   following environment variable, ``QGIS_AUTH_PASSWORD_FILE``.

Managing the master password
............................

Once set, the master password can be reset; the current master password will be
needed prior to resetting. During this process, there is an option to generate a
complete backup of the current database.

.. _figure_masterpass_reset:

.. figure:: img/auth-password-reset.png
   :align: center

   Resetting master password

If the user forgets the master password, there is no way to retrieve or override
it. There is also no means of retrieving encrypted information without knowing
the master password.

If a user inputs their existing password incorrectly three times, the dialog
will offer to erase the database.

.. _figure_masterpass_pwd:

.. figure:: img/auth-password-invalid-3times.png
   :align: center

   Password prompt after three invalid attempts

Authentication Configurations
-----------------------------

You can manage authentication configurations from :guilabel:`Configurations` in
the :guilabel:`Authentication` tab of the QGIS Options dialog
(:menuselection:`Settings --> Options`).

.. _figure_authconfigeditor:

.. figure:: img/auth-editor-configs2.png
   :align: center

   Configurations editor

Use the |signPlus| button to add a new configuration, the |signMinus| button
to remove configurations, and the |symbologyEdit| button to modify existing ones.

.. _figure_authconfigeditor_add:

.. figure:: img/auth-config-create_authcfg-id.png
   :align: center

   Adding config from within Configuration editor

The same type of operations for authentication configuration management (Add,
Edit and Remove) can be done when configuring a given service connection, such
as configuring an OWS service connection. For that, there are action buttons
within the configuration selector for fully managing configurations found
within the authentication database. In this case, there is no need to go to the
:guilabel:`configurations` in :guilabel:`Authentication` tab of QGIS options
unless you need to do more comprehensive configuration management.

.. _figure_authconfigeditor_wms:

.. figure:: img/auth-selector-wms-connection.png
   :align: center

   WMS connection dialog showing :guilabel:`Add`, :guilabel:`Edit`, and :guilabel:`Remove` 
   authentication configuration buttons

When creating or editing an authentication configuration, the info required is
a name, an authentication method and any other info that the authentication
method requires (see more about the available authentication types in
:ref:`authentication_methods`).

.. _authentication_methods:

Authentication Methods
----------------------

Available authentications are provided by C++ plugins much in the same way data
provider plugins are supported by QGIS. The method of authentication that can
be selected is relative to the access needed for the resource/provider, e.g.
HTTP(S) or database, and whether there is support in both QGIS code and a
plugin. As such, some authentication method plugins may not be applicable
everywhere an authentication configuration selector is shown. A list of
available authentication method plugins and their compatible resource/providers
can be accessed going to :menuselection:`Settings --> Options` and, in the
:guilabel:`Authentication` tab, click the |options| :guilabel:`Installed Plugins`
button.

.. _figure_authmethod:

.. figure:: img/auth-method-listing.png
   :align: center

   Available method plugins list

Plugins can be created for new authentication methods that do not require QGIS
to be recompiled. Since the support for plugins is currently (since QGIS 2.12)
C++-only, QGIS will need to be restarted for the new dropped-in plugin to become
available to the user. Ensure your plugin is compiled against the same target
version of QGIS if you intend to add it to an existing target install.

.. _figure_authmethod_http:

.. figure:: img/auth-config-create_basic-auth.png
   :align: center

   Basic HTTP authentication configs

.. _figure_authmethod_esritoken:

.. figure:: img/auth-config-create_esritoken.png
   :align: center

   ESRI Token authentication configs

.. _figure_authmethod_oauth2:

.. figure:: img/auth-config-create_oauth2.png
   :align: center

   OAuth2 authentication configs

.. _figure_authmethod_pki:

.. figure:: img/auth-config-create_pem-der-paths.png
   :align: center

   PKI paths authentication configs

.. _figure_authmethod_pkcs:

.. figure:: img/auth-config-create_pkcs12-paths.png
   :align: center

   PKI PKCS#12 file paths authentication configs

.. _figure_authmethod_stored:

.. figure:: img/auth-config-create_stored-identity2.png
   :align: center

   Stored Identity authentication configs

.. note::

   The Resource URL is currently an *unimplemented* feature that will eventually
   allow a particular configuration to be auto-chosen when connecting to
   resources at a given URL.

Master Password and Auth Config Utilities
-----------------------------------------

Under the Options menu (:menuselection:`Settings --> Options`) in the
:guilabel:`Authentication` tab, there are several utility actions to manage the
authentication database and configurations:

.. _figure_authconfiutils:

.. figure:: img/auth-editor-configs_utilities-menu.png
   :align: center

   Utilities menu

* **Input master password**:
  
  * Opens the master password input dialog, independent of performing any
    authentication database command.
    
* **Clear cached master password**:

  * Unsets the master password if it has been set via input dialog.
  
* **Reset master password**:

  * Opens a dialog to change the master password (the current password
    must be known) and optionally back up the current database.

* **Clear cached authentication configurations**: Clears the internal lookup cache
  for configurations used to speed up network connections. This does not clear
  QGIS’s core network access manager’s cache, which requires a relaunch of QGIS.

* **Reset master password**: Replaces the current master password for a new one.
  The current master password will be needed prior to resetting and a backup of
  database can be done.

* **Remove all authentication configurations**: Clears the database of all
  configuration records, without removing other stored records.

* **Erase authentication database**: Schedules a backup of the current database
  and complete rebuild of the database table structure. These actions are
  scheduled for a later time, so as to ensure other operations like project
  loading do not interrupt the operation or cause errors due to a temporarily
  missing database.

  .. _figure_authconfiutilsdb:

  .. figure:: img/auth-db-erase.png
     :align: center

     DB erase verification menu

Using authentication configurations
-----------------------------------

Typically, an authentication configuration is selected in a configuration dialog
for a network services (such as WMS). However, the selector widget can be
embedded anywhere authentication is needed or in non-core functionality, like in
third-party PyQGIS or C++ plugins.

When using the selector, :guilabel:`No authentication` is displayed in the
pop-up menu control when nothing is selected, when there are no configurations
to choose from, or when a previously assigned configuration can no longer be
found in the database. The :guilabel:`Type` and :guilabel:`Id` fields are
read-only and provide a description of the authentication method and the
config’s ID respectively.

.. _figure_authconfigselector:

.. figure:: img/auth-selector-no-authentication.png
   :align: center

   Authentication configuration selector with no authentication

.. _figure_authconfigselector_pkcs:

.. figure:: img/auth-selector-pkcs12-authentication.png
   :align: center

   Authentication configuration selector with selected config

Python bindings
---------------

All classes and public functions have sip bindings, except ``QgsAuthCrypto``,
since management of the master password hashing and auth database encryption
should be handled by the main app, and not via Python.
See :ref:`authentication_security_considerations` concerning Python access.


.. Substitutions definitions - AVOID EDITING PAST THIS LINE
   This will be automatically updated by the find_set_subst.py script.
   If you need to create a new substitution manually,
   please add it also to the substitutions.txt file in the
   source folder.

.. |options| image:: /static/common/mActionOptions.png
   :width: 1em
.. |signMinus| image:: /static/common/symbologyRemove.png
   :width: 1.5em
.. |signPlus| image:: /static/common/symbologyAdd.png
   :width: 1.5em
.. |symbologyEdit| image:: /static/common/symbologyEdit.png
   :width: 1.5em