Control access to WebDav/Apache using Python - python

I want to give users access to WebDav using Apache, but I want to autenticate them first and give each user access to a specific folder. All authentication must be done against a Django-based database. I can get the Django-authentication working myself, but I need help with the part where I authenticate each user and provide them with a dedicated webdav user-specific area.
Any hints?

First, for you other readers, my authentication was done against Django using a WSGI authentication script.
Then, there's the meat of the question, giving each Django user, in this case, their own WebDav dir separated from other users. Assuming the following WebDAV setup in the Apache virtual sites configuration (customarily in /etc/apache2/sites-enabled/)
<Directory /webdav/root/on/server>
DAV On
# No .htaccess allowed
AllowOverride None
Options Indexes
AuthType Basic
AuthName "Login to your webdav area"
Require valid-user
AuthBasicProvider wsgi
WSGIAuthUserScript /where/is/the/authentication-script.wsgi
</Directory>
Note how there's no public address for WebDav set up yet. This, and the user area thing, is fixed in two lines in the same config file (put these after the ending clause):
RewriteEngine On
RewriteRule ^/webdav-url/(.*?)$ /webdav/root/on/server/%{LA-U:REMOTE_USER}/$1
Now, webdav is accessed on http://my-server.com/webdav-url/ The user gets a login prompt and will then land in a subdirectory to the webdav root, having the same name as their username. LA-U: makes Apache "look ahead" and let the user sign in before determining the mounting path, which is crucial since that path depends on the user name. Without some rewrite-rule there will be no URL, and the user won't get a login prompt. In other words, LA-U avoids a catch-22 for this type of login handling.
Precautions: requires mod_rewrite to be enabled, and user names must be valid as dir names without any modification. Also, the user dirs won't be created automatically by these commands, so their existence must be assured in some other way.

You might find that the apache mod_authn_dbd module gives you what you want. This module lets apache check an SQL database for authentication and authorization. You would use this directive in the <Location>, <Directory> (etc) area that you are trying to protect:
<Directory /usr/www/myhost/private>
# other config ere
# mod_authn_dbd SQL query to authenticate a user
AuthDBDUserPWQuery \
"SELECT password FROM authn WHERE user = %s"
</Directory>
Strictly speaking, this means you're authenticating against Django's database, not against the Django app itself. Note that you have full control over the query, so you CAN combine it with other parameters in any tables to make sure the user is in good standing, or in certain groups, or whatever, before allowing the authentication.
You may need to fuss around a bit to make sure the hashing mechanisms used are the same in both apache and django.
If this doesn't suit, consider moving your authentication out of the django database into, say, an LDAP server. With a custom authentication backend (there are existing LDAP implementations for django out there), django will happily use LDAP... and LDAP auth/auth support in Apache is quite robust.

I know this question is old, but just as an addition... If you are using mod_python, you may also be interested in "Authenticating against Django’s user database from Apache" section of Django documentation.

Related

SAML / Shibb authentication in Django

I am newbie to Django, but I know how to create a simple application in python-Django how to add new page , how to link it into url file etc.
Now what I am trying to do, I am trying to create a very simple webapp where On the landing page I will have a login link.
When the user clicks on this link it should go to george washington universities authentication window and then I can enter my university's credential and it should authenticate and come back to a page stating ** Login Successful**
I have gone through many tutorials, but all looks very confusing.
I have installed xmlsec1, pysaml2, djangosaml2 modules but even after that I was clueless what to do next. I never felt so much clueless like I am feeling for this authentication module.
It will be great if anyone can guide me with the process.
You didn't say what web server you were using but, on Apache, I'd recommend you use the mod_shib Apache module in conjunction with the Django authentication middleware.
In broad strokes, you are going to let Apache/mod_shib do the SAML heavy lifting and interact with the IdP and you are going to let Django manage users for you. You are going to connect the two by using a piece of Django authentication middleware that authenticates users using the REMOTE_USER environment variable to communicate between Apache and the Django app.
So, first setup Django using Django authentication as described in the Django documentation. Validate that you can create a user using the admin tools and that you can login and establish a session using the Django authentication methods.
Once you have simple, local login working, install the RemoteUser middleware and validate that, by setting the REMOTE_USER environment variable, you can cause your Django app to log a user in (you can do all this testing using the development server locally on your development machine).
Once you have demonstrated that you can log a user in by having the REMOTE_USER environment set, you need to install the Apache shibboleth module, mod_shib and use it to protect the root of your application.
Assuming your application is located at /mysite the config in your virtualhost section would include:
<Location /mysite>
ShibRequestSetting redirectToSSL 443
AuthType shibboleth
ShibRequestSetting requireSession 1
Require valid-user
</Location>
That configuration will tell apache that the /mysite path requires mod_shib to get involved and forces the communication over ssl/tls.
I will not go through all the configuration steps needed to install and configure shibboleth but, basically, you want to set your application default (shibboleth2.xml file) with REMOTE_USER=eppn (if you want to use another attribute like eptid you would specify that); this tells the module which attribute to stuff in the REMOTE_USER environment variable. Again, the shib doc is pretty clear here so I won't go into detail about how to redirect to your university IdP but, basically, you will create an entry in your Sessions section of the form:
<SSO entityID="https://idp.testshib.org/idp/shibboleth">
Where you would substitute your IdP location for the testshib URL shown above.
Note that we are setting REMOTE_USER to the eppn value and that that value will be interpreted by the Django auth middleware as the user's username; you will need to create Django users with usernames that are the same as their eppn for this to work. You can also allow Django to auto-provision new accounts if, for instance, you deem IdP authentication sufficient evidence to create a new user account but, with auto-provisioning, only the minimal bits get setup; you would still need to go into that account and set first name, last name, phone, etc.
The net effect is that, whenever an unauthenticated user tries to visit a location under /mysite, they will be redirected to your university IdP, they will logon there and be redirected back. The mod_shib module (in conjunction with the shibd daemon running in the background) will handle the attribute unpacking and the session state with the IdP and will set the eppn value in the REMOTE _USER environment variable. Assuming that your Django application was setup correctly with apache, it will be invoked and the RemoteUser middleware will use the eppn value set in the REMOTE_USER environment variable to lookup the user with that username in the authentication database. If it finds a user, it will complete the Django login process (i.e. set the user object in the request, set the session state, etc.)
One more thing. To talk to you university IdP and have it release attributes to your application (i.e. eppn), you will need to do three things:
Import their IdP metadata
Export your SP metadata and have your university identity folks import it
Get your university identity team to release eppn to you
Just be aware that those three steps can be a challenge and may take non-trivial time and homework.
One more one more thing: I would recommend verifying the SAML setup separate from your Django app/middleware integration. Using the simplest mechanism you are comfortable with (simple wsgi app, php script, whatever) create a page that will simply dump the REMOTE_USER environment variable when browsed then protect that first. Once you have that page redirecting to your IdP and dumping the correct eppn in REMOTE_USER on return, then you can move on to the Django bits.

Django remote user authentication and security

I am using Django remote user authentication in a project. What I am actually using is just django.contrib.auth.RemoteUserBackend without the middleware, and manually calling authenticate after having checked with the backend that the user is legitimate.
Reading the source of the middleware, it seems that it just takes the username from a header in the request and then authenticates the user against the backend passing this username. The remote user backend, in turn, just merrily logs the user in with whatever username was passed. The user has then access to every area that requires a valid login.
Isn't this just a huge security flaw? How is this meant to be used?
In my case I should be safe, since the only call to authenticate comes after a successful remote identity verification, but I am wondering the reason why the middleware was introduced.
Let me turn this around on you: if you think this is a security flaw, then try writing an exploit that sets the REMOTE_USER header in a request to your app and see what happens.
REMOTE_USER dates back to the early days of the web when CGI pages were executed locally as the user you were hitting the web page with. REMOTE_USER is actually the name of a unix environment variable that denotes the active user. As security models for web servers changed, this scheme was preserved for compatibility. Now even IIS supports it to transparently handle Active Directory logins.
All user-passed headers begin with HTTP_. Otherwise, you couldn't trust on any header information, like SERVER_NAME, which would be an enormous mess.
Django 'merrily logs the user in' because your webserver has checked that the visitor has valid credentials for that username, and set the header accordingly.
If you trust your webserver (e.g. Apache) to set the REMOTE_USER (or other) header correctly, then it's not a security flaw.
You can see the documentation here. A user can't send a request with customer header for REMOTE_USER.
Warning
Be very careful if using a RemoteUserMiddleware subclass with a custom HTTP header. You must be sure that your front-end web server always sets or strips that header based on the appropriate authentication checks, never permitting an end-user to submit a fake (or “spoofed”) header value. Since the HTTP headers X-Auth-User and X-Auth_User (for example) both normalize to the HTTP_X_AUTH_USER key in request.META, you must also check that your web server doesn’t allow a spoofed header using underscores in place of dashes.
This warning doesn’t apply to RemoteUserMiddleware in its default configuration with header = 'REMOTE_USER', since a key that doesn’t start with HTTP_ in request.META can only be set by your WSGI server, not directly from an HTTP request header.

Separate Django sites with a common authetication/registration backend

I need split my current Django application into two sites.
Site A will contain the public facing site which would contain all the static pages and the registration system.
The other site — Site B — is the site for registered users. They can also log-in to application site through Site B.
If I'm not mistaken, I can use django.contrib.sites framework to accomplish the task of having multiple sites but can have a common authetication/registration backend?
How can I accomplish this?
Thanks.
Django's django.contrib.sites framework is nice if both sites are running under the same server and access the same database. If you have a distributed application (different sites on different hosts or different sites on different databases), you can resort to single sign-on solutions.
I use OpenID with a custom provider to centralize logins between apps running on different databases. Other solutions include CAS (provider and consumer).
For this case, you would have 2 settings.py files called settings_A.py and settings_B.py which specify from settings import *
A would have SITE=1 and B would have SITE=B. you can then set these files in your apache configs by setting the environment variable for each virtual host DJANGO_SETTINGS_MODULE=settings_A and DJANGO_SETTINGS_MODULE=settings_B
Then you set up the contrib.sites app with your 2 domain names bound to the appropriate site ID, and your flatpages will be able to be bound to either or both sites.
Lastly, in settings_A.py settings_B.py you either specify seperate root urlconfs or you use the use settings.SITE in your urlconfs to enable and disable groups of urls for each site.
Hope this helps
EDIT: To clarify: as long as you use the same database and SECRET_KEY between both sites, you can use the same user accounts between them too. If the sites are of the form example.com and private.example.com then setting SESSION_COOKIE_DOMAIN to .example.com will allow the session to carry over between both sites.
You could use (external) LDAP authentication for both sites. You would need a LDAP server somewhere reachable for both sites. I never used this and I don't know how well it integrates with Django auth though. See http://packages.python.org/django-auth-ldap/

WSGI/Django: pass username back to Apache for access log

My Django app, deployed in mod_wsgi under Apache using Django's standard WSGIHandler, authenticates users via form login on the Django side. So to Apache, the user is anonymous. This makes the Apache access log less useful.
Is there a way to pass the username back through the WSGI wrapper to Apache after handling the request, so that it appears in the Apache access log?
(Versions: Django 1.1.1, mod_wsgi 2.5, Apache 2.2.9)
You can only do it if using embedded mode and only if you use a separate package called apswigpy, which provides a Python binding for original Apache request object. The mod_wsgi package provides an optional mechanism for allowing original Apache request object to be passed as Python CObject reference in WSGI environment. You use that in conjunction with apswigpy something like:
from apache.httpd import request_rec
r = request_rec(environ['apache.request_rec'])
r.user = user
At least I think that will setup the appropriate information which access logging can then use.
You should really take this discussion over to the mod_wsgi mailing list.
You could use mod_auth_tkt. An auth_tkt is a signed cookie with the user id that Apache can understand. Your web application would have to set the cookie when the user logs in and out. Apache can derive a REMOTE_USER from the cookie, pass it to your web app or a non-Django web application running on the same server, include it in logs, whatever.
This probably isn't what you're expecting, but you could use the username in your URL scheme. That way the user will be in the path section of your apache logs.
You'd need to modify your authentication so that auth-required responses are obvious in the apache logs, otherwise when viewing the logs you may attribute unauthenticated requests to authenticated users. E.g. return a temporary redirect to the login page if the request isn't authenticated.
Correct me if I'm wrong, but what's stopping you from creating some custom middleware that sets a cookie equal to the display name of the current user logged in. This middleware will run on every view, so even though technically the user could spoof his username to display whatever he wants it to display, it'll just be reset anyway and it's not like its a security risk because the username itself is just for log purposes, not at all related to the actual user logged in. This seems like a simple enough solution, and then Apache log can access cookies so that gives you easiest access. I know some people wouldn't like the idea of a given user spoofing his own username, but i think this is the most trivial solution that gets the job done. Especially, in my case, when it's an iPhone app and the user doesn't have any direct access to a javascript console or the cookies itself.
for latest (Django 2.x, Apache 2.4) Tested
source https://www.django-rest-framework.org/api-guide/authentication/#apache-mod_wsgi-specific-configuration
you need to add WSGIPassAuthorization on in either server config, virtual host, directory or .htaccess

Subdomains and Logins

If you multiple subdomains e.g.:
sub1.domain_name.com
sub2.domain_name.com
Is there a way to have a user be able to log into both of these without issues and double login issue?
The platform is Python, Django.
Without information regarding what platform you are using, it is difficult to say. If you use cookies to store authentication information, and you are using subdomains as you describe, then you can force the cookie to be issued for the highest level domain, e.g. domain_name.com.
This will be accessable by both sub1 and sub2, and they could each use that for their authentication.
EDIT:
In the settings.py for each application running under the subdomains, you need to put
SESSION_COOKIE_DOMAIN = ".domain_name.com" as per the django docs
Yes. Just set the cookie on the domain ".domain_name.com" and the cookie will be available to sub1.domain_name.com, and sub2.domain_name.com.
As long as you maintain your session information on both domains, you should be fine.
This is a very common practice, and is why you can log into your Google Account at http://www.google.com/ and still be logged in at http://mail.google.com.

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