[MODPYTHON-169] Add feature to allow mod_python to be an auth provider.

• Type: New Feature
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: core
• Assignee: Graham Phillip Dumpleton
• Reporter: Graham Phillip Dumpleton
• Created: 05/May/06 17:13
• Updated: 14/Jun/07 13:01

Description

In Apache 2.2, the implementation of authentication has been split into two parts. The first is that which handles the specifics of negotiating with a client for a specific authentication mechanism type, for example, Basic or Digest authentication. The second part is that which handles the specifics of verifying the actual users credentials, for example, by looking the user up in a dbm database, ldap or some other type of user database.

The second part of this is referred to as the auth provider and in Apache 2.2 it is possible to hook in additional providers. This means that the any builtin support in Apache for Basic and Digest authentication mechanism can be used, but the verification could be done by some arbitrary user code. Such verification could be done in Python, if mod_python allowed one to define the necessary auth provider hooks.

To this end, proposed that mod_python be extended such that when using Apache 2.2, that it is possible to say:

AuthType Basic
AuthName "Restricted Files"
AuthBasicProvider mod_python
PythonAuthBasicProvider somemodule

or:

AuthType Digest
AuthName "Restricted Files"
AuthDigestProvider mod_python
PythonAuthDigestProvider somemodule

That is, by specifying mod_python in conjunction with AuthBasicProvider or AuthDigestProvider directives, it triggers mod_python to be given option of satisfying need to perform verification of user credentials. The function to be called for each being given by the PythonAuthBasicProvider and PythonAuthDigestProvider respectively.

The argument to these directives would be a module name, in which case a function of the name "authbasicprovider" or "authdigestprovider" will be expected to exist. If wanting to specify a particular module, like in handler directives, would also be possible to say:

PythonAuthBasicProvider somemodule::check_password
PythonAuthDigestProvider somemodule::get_realm_hash

Note that the prototype of the function for each would not be like existing handlers and is different in each case. For the Basic auth mechanism, an example function would be:

users =

{ ... }

def authbasicprovider(req, user, password):

1. could consult req.auth_name() to get realm

if user not in users:
return apache.AUTH_USER_NOT_FOUND

1. assuming passwords are stored in clear text

if users[user] != password:
return apache.AUTH_DENIED

return apache.AUTH_GRANTED

Exceptions would be translated into apache.AUTH_GENERAL_ERROR, or function could explicitly return it. Could also allow explicit exception of type apache.SERVER_RETURN like in handlers but where argument is auth values.

For Digest authentication, function would be:

def authdigestprovider(req, user, realm):

1. could select database based on 'realm'

if user not in users:
return None

1. assuming passwords are stored in clear text

return md5.new("%s:%s:%s" % (user, realm, users[user])).hexdigest()

In this later function, return None indicates apache.AUTH_USER_NOT_FOUND. An apache.SERVER_RETURN exception could also be used with that value as argument. Returning of an actual string would imply apache.AUTH_USER_FOUND. Unexpected exceptions taken as apache.AUTH_GENERAL_ERROR, or could be raised explicitly using apache.SERVER_RETURN exception.

What all this would mean is that you would never need to write an authenhandler again using mod_python, as you could rely on any type of authenhandler builtin to Apache or as as supported by some third party Apache module. All you would need to do is supply the auth provider or Basic or Digest authentication as necessary to support verification of the user.