Verifying a FAS instance via JSON?

[Mike McGrath]

On Wed, 14 Jul 2010, Paul W. Frields wrote:

> On Sun, Jul 11, 2010 at 03:03:02PM -0400, Toshio Kuratomi wrote:
> > On Sun, Jul 11, 2010 at 12:52:33PM -0400, Paul Frields wrote:
> > > This is probably going to be a very naive question, so bear with me.
> > > I'm trying my hand at an AuthFAS plugin for Drupal.
> > >
> > Note: If this is going to run outside of infrastructure it's probably best
> > not to auth against FAS due to the insecurity of getting people used to
> > typing their FAS credentials into third party websites..  If it's going to
> > run inside of infrastructure we should think about whether we want to run
> > Drupal.  If it's going to run on some third party against some third party
> > FAS then we'd like to know who else is running FAS :-)
>
> It's the second case, at least as far as a public test instance.  One
> of the things the Insight group has asked is that we investigate other
> platforms, so I set about writing this plugin to try on a publictest
> box against pt3's "FakeFAS" instance.  It's not meant to be run on a
> random server, rather in the same context that we have run a similar
> Zikula plugin.  Although I'm working on the code on my own box for
> now, that's meant to be very short-term.
>
> > > As part of that
> > > code, I'm trying to verify the setting of a FAS instance URL, by using
> > > curl to hit https://<URL>/json/ (like
> > > https://admin.fedoraproject.org/accounts/json/). I give the
> > > administrator an opportunity to enter FAS credentials to be used in
> > > the curl process.
> > >
> > > The code is found here (in the authfas_admin_validate() function):
> > > http://fedorapeople.org/gitweb?p=pfrields/public_git/drupal-authfas-6x.git;a=summary
> > >
> > > If I'm at a browser and I hit https://admin.fp.o/accounts/json/
> > > directly, I have to enter my username/passphrase, and then I get a
> > > JSON result that includes a 'help' element, which is what I'm checking
> > > for in the code. This is sort of an optional step, really. I wanted to
> > > make it possible for people to know if they made a typo in the URL.
> > > But if I have to drop that validation step, and simply depend on the
> > > admin to get it right, that's probably acceptable. Maybe I'm trying to
> > > be too clever.
> > >
> > > In any case, regardless of the username and password I use, I don't
> > > get back a positive result. It's possible that's because I'm getting a
> > > login or some sort of CSRF intermediary request. I confess I haven't
> > > had a ton of time to dig deeply into the problem. I was hoping someone
> > > here would be able to say, "Here's something you need to do if you're
> > > using curl like that...".  The curl code here is drawn from the
> > > original Auth_FAS.php on the wiki, but I'm not sure if the changes I
> > > made are all kosher.
> > >
> > Are you just trying to get username/password verification from fas?  or are
> > you trying to get fas to give you a cookie that fas verifies is correct
> > everytime?  I believe our mediawiki install does the former.
>
> The former.
>
> > A quick look at the code leads me to believe that you aren't requesting json
> > data explicitly and therefore the login page is being returned as html
> > rather than json.  Requesting json should make fas return an error if you
> > aren't logged in/handing in valid credentials.
> >
> >
> > A few other differences between the python-fedora implementation and this:
> >
> > * I think that giving "username=XXX" as a param will yield an error.
> > * I think you need to have FOLLOWLOCATION=True so you follow redirects.
> >
> > Here's what I *think* is php to implement that:
> >
> > -     curl_setopt($ch, CURLOPT_USERAGENT, "Drupal AuthFAS 0.1");
> > -     curl_setopt($ch, CURLOPT_POSTFIELDS, "username=".urlencode($username)."&user_name=".urlencode($username).  "&password=".urlencode($password)."&login=Login");
> > +     curl_setopt($ch, CURLOPT_HEADERS, "user-agent: Drupal AuthFAS 0.1; Accept: application/json;");
> > +     curl_setopt($ch, CURLOPT_POSTFIELDS, "user_name=".urlencode($username).  "&password=".urlencode($password)."&login=Login");
> > +     curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1)
> > +     curl_setopt($ch, CURLOPT_MAXREDIRS, 5)
> >
> > I could be off in the bushes with this, though.  If so, here's the
> > python-fedora code that connects to FAS.  Checking for differences in what
> > you're giving curl and what it's giving curl is pretty straightforward:
> >
> > http://bzr.fedorahosted.org/bzr/python-fedora/python-fedora-devel/annotate/head%3A/fedora/client/proxyclient.py#L146
>
> Thanks Toshio!  I'll take a look at that code and reply here if I have
> more questions.
>

I'm happy to help and check this.  Feel free to ping me on IRC.

	-Mike