[mod_python] PythonAuthzHandler not working

Jim Gallacher jpg at jgassociates.ca
Fri May 5 08:21:50 EDT 2006

Graham Dumpleton wrote:
> On 24/04/2006, at 1:50 PM, Graham Dumpleton wrote:
>> Jim Gallacher wrote ..
>>> Ultimately however it seems to me there is a bug in mod_python.c related
>>> to the whole AuthAthoritative business. Consider the following code
>>> pulled from the python_handler function. (mod_python.c line 1412
>>> revision 396250):
>>>     if (strcmp(phase, "PythonAuthenHandler") == 0) {
>>>           ... snip ...
>>>           if (result == HTTP_UNAUTHORIZED)
>>>           {
>>>                if   (! conf->authoritative)
>>>                      result = DECLINED;
>>> conf->authoritative is initialized to 1, but we don't have an Apache
>>> directive to set the value. I wonder if the assumption was that this was
>>> set by AuthAuthoritative, or if it there was an oversight in not adding
>>> a new directive? Either way it's a bug. Mod_python should not concern
>>> itself with AuthAuthoritative, as that is for use by mod_auth, so we
>>> really need our on directive.
>>> As confirmation I modified python_handler to log conf->authoritative and
>>> indeed it's value is unaffected by the AuthAthoritative setting. In it's
>>> current state, PythonAuthenHander will *always* be authoritative.
>>> Other mod_auth_* modules define their own  authoritative directives, for
>>> example: AuthDBMAuthoritative, AuthLDAPAuthoritative,
>>> AuthMySQLAuthoritative and Anonymous_Authoritative. Following the most
>>> common pattern I would suggest we add AuthPythonAuthoritative.
>>> This issue may also be important to
>>> http://issues.apache.org/jira/browse/MODPYTHON-129
>> I've noted the PythonAuthenHandler code in python_handler many times and
>> although I need to go back and look at it again I have been thinking
>> that that section of code may possibly be partly bogus and shouldn't be
>> in there. The warning message about req.user not being set is possibly
>> helpful, but why should mod_python be making a decision to change an
>> unauthorized response back to a declined and why should it be generating
>> a WWW-Authenticate header with an assumption that Basic authorisation
>> is being used when it may well not be. What is going to happen if I write
>> an authenhandler for Digest authentication and it returns unauthorised,
>> mod_python will obliterate any WWW-Authenticate header I may have
>> placed there specific to Digest authentication.
>> Thus I don't necessarily think it is a case of amending it some way, it
>> may be a case of obliterating it and make people do the correct thing
>> in their handlers to begin with rather than providing a crutch to fix 
>> their
>> omissions. This may mean adding means of calling further auth related
>> functions through the req object if there is something missing now,
>> such as access to ap_note_basic_auth_failure().
> FWIW, my concerns about something being a bit wrong with the code are a
> baseless in as much as ap_note_basic_auth_failure() only adds the header
> is AuthType is set to Basic. Thus it cant obliterate a Digest header.

That is incorrect. ap_note_basic_auth_failure() checks if the auth type 
is "Basic". If so it sets the headers, otherwise it calls 
ap_note_auth_failure(). ap_note_auth_failure() also checks the auth type 
and will either call ap_note_basic_auth_failure if the type is "Basic", 
ap_note_digest_auth_failure() if the type is "Digest" or else just log 
an error.

ap_note_digest_auth_failure will sets the headers appropriately for 
digest authentication.

This doesn't mean we are correct in calling ap_note_basic_auth_failure, 
but doing so will not cause any problems as long as the AuthType is set 


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