authentication by reverse proxy

README.md

@@ -336,6 +336,33 @@ Put them in your `realms-wiki.json` config file.  Use the example below.
         }
     }
 
+### Authentication by reverse proxy
+
+If you configured realms behind a reverse-proxy or a single-sign-on, it is possible to delegate authentication to
+the proxy.
+
+    "AUTH_PROXY": true
+    
+Note: of course with that setup you must ensure that **Realms is only accessible through the proxy**.
+
+Example Nginx configuration:
+    
+    location / {
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header Host $http_host;
+        proxy_set_header REMOTE_USER $remote_user;
+    
+        proxy_pass http://127.0.0.1:5000/;
+        proxy_redirect off;
+    }    
+    
+By default, Realms will look for the user ID in `REMOTE_USER` HTTP header. You can specify another header name with:
+
+    "AUTH_PROXY_HEADER_NAME": "LOGGED_IN_USER"
+    
+
+
 ## Running
 
     realms-wiki start

realms/__init__.py

@@ -1,6 +1,7 @@
 from __future__ import absolute_import
 
 import sys
+import logging
 # Set default encoding to UTF-8
 reload(sys)
 # noinspection PyUnresolvedReferences
@@ -17,7 +18,7 @@ from functools import update_wrapper
 import click
 from flask import Flask, request, render_template, url_for, redirect, g
 from flask_cache import Cache
-from flask_login import LoginManager, current_user
+from flask_login import LoginManager, current_user, logout_user
 from flask_sqlalchemy import SQLAlchemy
 from flask_assets import Environment, Bundle
 from flask_ldap_login import LDAPLoginManager
@@ -215,6 +216,23 @@ def create_app(config=None):
         if app.config.get('DB_URI'):
             db.metadata.create_all(db.get_engine(app))
 
+    if app.config["AUTH_PROXY"]:
+        logger = logging.getLogger("realms.auth")
+
+        @app.before_request
+        def proxy_auth():
+            from realms.modules.auth.proxy.models import User as ProxyUser
+            remote_user = request.environ.get(app.config["AUTH_PROXY_HEADER_NAME"])
+            if remote_user:
+                if current_user.is_authenticated():
+                    if current_user.id == remote_user:
+                        return
+                    logger.info("login in realms and login by proxy are different: '{}'/'{}'".format(
+                        current_user.id, remote_user))
+                    logout_user()
+                logger.info("User logged in by proxy as '{}'".format(remote_user))
+                ProxyUser.do_login(remote_user)
+
     return app
 
 # Init plugins here if possible

realms/config/__init__.py

@@ -100,6 +100,10 @@ class Config(object):
     # Name of page that will act as home
     WIKI_HOME = 'home'
 
+    # Should we trust authentication set by a proxy
+    AUTH_PROXY = False
+    AUTH_PROXY_HEADER_NAME = "REMOTE_USER"
+
     AUTH_LOCAL_ENABLE = True
     ALLOW_ANON = True
     REGISTRATION_ENABLED = True

realms/modules/auth/__init__.py

@@ -5,8 +5,10 @@ from flask_login import login_url
 
 from realms import login_manager
 
+
 modules = set()
 
+
 @login_manager.unauthorized_handler
 def unauthorized():
     if request.method == 'GET':

realms/modules/auth/models.py

@@ -17,6 +17,7 @@ from . import modules
 def load_user(auth_id):
     return Auth.load_user(auth_id)
 
+
 auth_users = {}
 
 
@@ -40,7 +41,9 @@ class Auth(object):
     def login_forms():
         forms = []
         for t in modules:
-            forms.append(Auth.get_auth_user(t).login_form())
+            form = Auth.get_auth_user(t).login_form()
+            if form:
+                forms.append(form)
         return "<hr />".join(forms)
 
 

realms/modules/auth/proxy/__init__.py

@@ -0,0 +1,5 @@
+from __future__ import absolute_import
+
+from realms.modules.auth.models import Auth
+
+Auth.register('proxy')

realms/modules/auth/proxy/models.py

@@ -0,0 +1,42 @@
+from __future__ import absolute_import
+
+from flask_login import login_user
+
+from realms.modules.auth.models import BaseUser
+
+
+users = {}
+
+
+class User(BaseUser):
+    type = 'proxy'
+
+    def __init__(self, username, email='null@localhost.local', password="dummypassword"):
+        self.id = username
+        self.username = username
+        self.email = email
+        self.password = password
+
+    @property
+    def auth_token_id(self):
+        return self.password
+
+    @staticmethod
+    def load_user(*args, **kwargs):
+        return User.get_by_id(args[0])
+
+    @staticmethod
+    def get_by_id(user_id):
+        return users.get(user_id)
+
+    @staticmethod
+    def login_form():
+        return None
+
+    @staticmethod
+    def do_login(user_id):
+        user = User(user_id)
+        users[user_id] = user
+        login_user(user, remember=True)
+        return True
+

realms/modules/auth/views.py

@@ -1,7 +1,7 @@
 from __future__ import absolute_import
 
 from flask import current_app, render_template, request, redirect, Blueprint, flash, url_for, session
-from flask_login import logout_user
+from flask_login import logout_user, current_user
 
 from .models import Auth
 
@@ -12,6 +12,8 @@ blueprint = Blueprint('auth', __name__, template_folder='templates')
 @blueprint.route("/login", methods=['GET', 'POST'])
 def login():
     next_url = request.args.get('next') or url_for(current_app.config['ROOT_ENDPOINT'])
+    if current_user.is_authenticated():
+        return redirect(next_url)
     session['next_url'] = next_url
     return render_template("auth/login.html", forms=Auth.login_forms())
 

realms/modules/wiki/views.py

@@ -18,7 +18,7 @@ blueprint = Blueprint('wiki', __name__, template_folder='templates',
 
 @blueprint.route("/_commit/<sha>/<path:name>")
 def commit(name, sha):
-    if current_app.config.get('PRIVATE_WIKI') and current_user.is_anonymous:
+    if current_app.config.get('PRIVATE_WIKI') and current_user.is_anonymous():
         return current_app.login_manager.unauthorized()
 
     cname = to_canonical(name)
@@ -35,7 +35,7 @@ def commit(name, sha):
 
 @blueprint.route(r"/_compare/<path:name>/<regex('\w+'):fsha><regex('\.{2,3}'):dots><regex('\w+'):lsha>")
 def compare(name, fsha, dots, lsha):
-    if current_app.config.get('PRIVATE_WIKI') and current_user.is_anonymous:
+    if current_app.config.get('PRIVATE_WIKI') and current_user.is_anonymous():
         return current_app.login_manager.unauthorized()
 
     diff = g.current_wiki.get_page(name, sha=lsha).compare(fsha)
@@ -50,7 +50,7 @@ def revert():
     commit = request.form.get('commit')
     message = request.form.get('message', "Reverting %s" % cname)
 
-    if not current_app.config.get('ALLOW_ANON') and current_user.is_anonymous:
+    if not current_app.config.get('ALLOW_ANON') and current_user.is_anonymous():
         return dict(error=True, message="Anonymous posting not allowed"), 403
 
     if cname in current_app.config.get('WIKI_LOCKED_PAGES'):
@@ -72,7 +72,7 @@ def revert():
 
 @blueprint.route("/_history/<path:name>")
 def history(name):
-    if current_app.config.get('PRIVATE_WIKI') and current_user.is_anonymous:
+    if current_app.config.get('PRIVATE_WIKI') and current_user.is_anonymous():
         return current_app.login_manager.unauthorized()
     return render_template('wiki/history.html', name=name)
 
@@ -197,7 +197,7 @@ def _tree_index(items, path=""):
 @blueprint.route("/_index", defaults={"path": ""})
 @blueprint.route("/_index/<path:path>")
 def index(path):
-    if current_app.config.get('PRIVATE_WIKI') and current_user.is_anonymous:
+    if current_app.config.get('PRIVATE_WIKI') and current_user.is_anonymous():
         return current_app.login_manager.unauthorized()
 
     items = g.current_wiki.get_index()
@@ -218,7 +218,7 @@ def page_write(name):
     if not cname:
         return dict(error=True, message="Invalid name")
 
-    if not current_app.config.get('ALLOW_ANON') and current_user.is_anonymous:
+    if not current_app.config.get('ALLOW_ANON') and current_user.is_anonymous():
         return dict(error=True, message="Anonymous posting not allowed"), 403
 
     if request.method == 'POST':
@@ -261,7 +261,7 @@ def page_write(name):
 @blueprint.route("/", defaults={'name': 'home'})
 @blueprint.route("/<path:name>")
 def page(name):
-    if current_app.config.get('PRIVATE_WIKI') and current_user.is_anonymous:
+    if current_app.config.get('PRIVATE_WIKI') and current_user.is_anonymous():
         return current_app.login_manager.unauthorized()
 
     cname = to_canonical(name)

realms/templates/layout.html

@@ -58,7 +58,7 @@
               </div>
             </form>
             </li>
-            {% if current_user.is_authenticated %}
+            {% if current_user.is_authenticated() %}
               <li class="dropdown user-avatar">
                 <a href="#" class="dropdown-toggle" data-toggle="dropdown">
                 <span>
@@ -68,7 +68,11 @@
                 </a>
                 <ul class="dropdown-menu">
                     <!--<li><a href="{{ url_for('auth.settings') }}"><i class="fa fa-gear"></i> Settings</a></li>-->
+                    {% if current_user.type != "proxy" %}
                         <li><a href="{{ url_for('auth.logout') }}"><i class="fa fa-power-off"></i> Logout</a></li>
+                    {% else %}
+                        <li><button class="btn btn-block" disabled="disabled"><i class="fa fa-power-off"></i> Logout</button></li>
+                    {% endif %}
                 </ul>
                 </li>
             {% else %}
@@ -109,7 +113,7 @@
       {% endfor %}
 
       var User = {};
-      User.is_authenticated = {{ current_user.is_authenticated|tojson }};
+      User.is_authenticated = {{ current_user.is_authenticated()|tojson }};
       {% for attr in ['username', 'email'] %}
         User.{{ attr }} = {{ current_user[attr]|tojson }};
       {% endfor %}