Switch to OIDC authentication

requirements.txt

@@ -1,4 +1,5 @@
+authlib
 click
 flask
 flask-login
-flask-ldap3-login
+ldap3

web/__init__.py

@@ -3,7 +3,6 @@ import syslog
 import secrets
 
 import flask
-import flask_ldap3_login
 import flask_login
 
 def create_app(test_config=None):
@@ -14,13 +13,13 @@ def create_app(test_config=None):
     settings = {
         'secret_key': secrets.token_hex(),
         'ldap_host': '',
-        'ldap_port': '636',
         'ldap_user': '',
         'ldap_pass': '',
-        'ldap_admin': '',
         'ldap_base_dn': '',
-        'ldap_user_dn': '',
-        'ldap_login_attr': 'userPrincipalName',
+        'oidc_tenant': '',
+        'oidc_client_id': '',
+        'oidc_client_secret': '',
+        'admin_group': '',
         'admin_mail': '',
         'wg_endpoint': '',
         'wg_port': '51820',
@@ -35,18 +34,15 @@ def create_app(test_config=None):
         db.write('settings', settings)
 
     app.config['SECRET_KEY'] = settings.get('secret_key', '')
-    app.config['LDAP_USE_SSL'] = True
-    app.config['LDAP_HOST'] = settings.get('ldap_host', '')
-    app.config['LDAP_PORT'] = int(settings.get('ldap_port', '636'))
-    app.config['LDAP_BASE_DN'] = settings.get('ldap_base_dn', '')
-    app.config['LDAP_USER_DN'] = settings.get('ldap_user_dn', '')
-    app.config['LDAP_BIND_USER_DN'] = settings.get('ldap_user', '')
-    app.config['LDAP_BIND_USER_PASSWORD'] = settings.get('ldap_pass', '')
-    app.config['LDAP_USER_LOGIN_ATTR'] = settings.get('ldap_login_attr', 'userPrincipalName')
-    app.config['LDAP_USER_SEARCH_SCOPE'] = 'SUBTREE'
 
     from . import auth
-    app.register_blueprint(auth.blueprint)
+    auth.init_app(app)
+
+    from . import errors
+    errors.init_app(app)
+
+    from . import system
+    system.init_app(app)
 
     from . import config
     app.register_blueprint(config.blueprint)
@@ -63,36 +59,6 @@ def create_app(test_config=None):
     from . import vpn
     app.register_blueprint(vpn.blueprint)
 
-    from . import system
-    system.init_app(app)
-
-    login_manager = flask_login.LoginManager(app)
-    ldap_manager = flask_ldap3_login.LDAP3LoginManager(app)
-    users = {}
-
-    @login_manager.user_loader
-    def load_user(id):
-        return users.get(id)
-
-    @ldap_manager.save_user
-    def save_user(dn, username, data, memberships):
-        user = auth.User(dn, username, data)
-        users[dn] = user
-        return user
-
-    @login_manager.unauthorized_handler
-    def unauth_handler():
-        return flask.redirect(flask.url_for('auth.login', next=flask.request.endpoint))
-
-    @app.errorhandler(TimeoutError)
-    def timeout_error(e):
-        return flask.render_template('busy.html')
-
-    @app.errorhandler(Exception)
-    def internal_server_error(e):
-        return flask.Response(f'something went catastrophically wrong: {e}',
-                status=500, mimetype='text/plain')
-
     @app.route('/')
     @flask_login.login_required
     def home():
@@ -101,17 +67,11 @@ def create_app(test_config=None):
     @app.route('/nodes')
     @flask_login.login_required
     def nodes():
-        try:
-            if not flask_login.current_user.is_admin:
-                return flask.Response('forbidden', status=403, mimetype='text/plain')
-            with db.locked('nodes'):
-                version = db.load('settings').get('version')
-                nodes = db.read('nodes')
-            return flask.render_template('nodes.html', version=version, nodes=nodes)
-        except TimeoutError:
-            return flask.render_template('busy.html')
-        except Exception as e:
-            return flask.Response(f'something went catastrophically wrong: {e}',
-                    status=400, mimetype='text/plain')
+        if not flask_login.current_user.is_admin:
+            return flask.Response('forbidden', status=403, mimetype='text/plain')
+        with db.locked('nodes'):
+            version = db.load('settings').get('version')
+            nodes = db.read('nodes')
+        return flask.render_template('nodes.html', version=version, nodes=nodes)
 
     return app

web/auth.py

@@ -1,39 +1,68 @@
+import authlib.integrations.flask_client
 import flask
 import flask_login
-import flask_ldap3_login.forms
+import urllib.parse
 
 from . import db
 
-blueprint = flask.Blueprint('auth', __name__, url_prefix='/auth')
+login_manager = None
+auth = None
+users = {}
 
 class User(flask_login.UserMixin):
-    def __init__(self, dn, username, data):
-        self.dn = dn
-        self.username = username
-        self.data = data
-        self.groups = set(data.get('memberOf', ()))
+    def __init__(self, userinfo):
+        self.username = userinfo['preferred_username']
+        self.groups = set(userinfo.get('groups', ()))
+        self.data = userinfo
         try:
-            self.is_admin = db.load('settings').get('ldap_admin') in self.groups
+            self.is_admin = db.load('settings').get('admin_group') in self.groups
         except:
             self.is_admin = False
 
     def __repr__(self):
-        return self.dn
+        return f'{self.username} {self.groups}'
 
     def get_id(self):
-        return self.dn
+        return self.username
 
-@blueprint.route('/login', methods=['GET', 'POST'])
-def login():
-    form = flask_ldap3_login.forms.LDAPLoginForm()
-    if form.validate_on_submit():
-        flask_login.login_user(form.user)
+def init_app(app):
+    settings = db.load('settings')
+    login_manager = flask_login.LoginManager(app)
+    oauth = authlib.integrations.flask_client.OAuth(app)
+    oauth.register(
+        name='azure',
+        server_metadata_url=f'https://login.microsoftonline.com/{settings.get("oidc_tenant")}/v2.0/.well-known/openid-configuration',
+        client_id=settings.get('oidc_client_id'),
+        client_secret=settings.get('oidc_client_secret'),
+        client_kwargs={'scope': 'openid profile email'})
+
+    @login_manager.user_loader
+    def load_user(username):
+        return users.get(username)
+
+    @login_manager.unauthorized_handler
+    def unauth_handler():
+        return flask.redirect(flask.url_for('login', next=flask.request.endpoint))
+
+    @app.route('/login')
+    def login():
+        return oauth.azure.authorize_redirect(flask.url_for('auth', _external=True))
+
+    @app.route('/auth')
+    def auth():
+        token = oauth.azure.authorize_access_token()
+        user = users[user.username] = User(oauth.azure.parse_id_token(token))
+        flask_login.login_user(user)
         return flask.redirect('/')
-    return flask.render_template('auth/login.html', form=form)
-
-@blueprint.route('/logout')
-@flask_login.login_required
-def logout():
-    flask_login.logout_user()
-    return flask.redirect('/')
 
+    @app.route('/logout')
+    def logout():
+        flask_login.logout_user()
+        return flask.redirect(
+            f'https://login.microsoftonline.com/common/oauth2/v2.0/logout?'
+            + urllib.parse.urlencode(
+                {
+                    'returnTo': flask.url_for('home', _external=True),
+                    'client_id': settings.get('oidc_client_id')
+                },
+                quote_via=urllib.parse.quote_plus))

web/errors.py

@@ -0,0 +1,17 @@
+import flask
+import werkzeug.exceptions
+
+def init_app(app):
+    @app.errorhandler(werkzeug.exceptions.HTTPException)
+    def http_error(e):
+        return e
+
+    @app.errorhandler(TimeoutError)
+    def timeout_error(e):
+        return flask.render_template('busy.html')
+
+    @app.errorhandler(Exception)
+    def internal_server_error(e):
+        return flask.Response(f'something went catastrophically wrong: {e}',
+                status=500, mimetype='text/plain')
+

web/templates/base.html

@@ -53,7 +53,7 @@ ul.keys a {
 {% if current_user.is_authenticated %}
 <div style="float:right;">
 {{ current_user['username'] }} |
-<a href="{{ url_for('auth.logout') }}">Odjava</a>
+<a href="{{ url_for('logout') }}">Odjava</a>
 </div>
 {% endif %}