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From <>
Subject RE: FW: Solr and LCF security at query time
Date Thu, 22 Apr 2010 09:02:04 GMT
Looking around for no-Apache java-only solutions to the AD authentication problem, it seems
to me that what we mainly have available is JAAS plus the following JAAS login module:

... which should permit AD authentication to take place,  if properly configured.
So, we *could* stipulate that the search component receive credentials, somehow, upon being
called, and then authenticate each time.  (There's a ticket cache involved, so this is not
as insane as it sounds).

But this architecture option makes me twitchy because I am unclear how exactly this would
help Tomcat interact with the browser to manage signon for a web application.  So it might
be better to push the authentication itself upstream into a module meant to be plugged into
Tomcat, and have Solr just receive and deal with the resulting ticket, and/or an authenticated,
domain-qualified user name.  The task of the LCF Solr search component or filter would then
be to do the following:

(1) Get hold of the ticket/authenticated user name, which will probably come in as some attribute
to the search that's presented to Solr.  (Someone needs to specify what this attribute is
called still).
(2) Invoke a configured LCF authority service with that user name, via http, and get back
a list of access tokens for the user
(3) Form the search expression with the user's access tokens (if it's a search component),
or filter the results using those access tokens (if it's a filter), remembering that every
document that's participating in security should have __ACCESS_TOKEN__document and __DENY_TOKEN__document

I've also been pondering whether which we should build: a search component or filter?  I think
there are advantages to both, so I think we should build both, and let people use what they

I think the technical aspects of building the Solr component are well understood by this group,
so the only open issue remains how to build a JAAS-based AD authentication module for tomcat
that would do what we needed.  I'll be doing more research as time permits...


From: Wright Karl (Nokia-S/Cambridge)
Sent: Wednesday, April 21, 2010 8:02 PM
Subject: RE: FW: Solr and LCF security at query time

Hi Peter,

I just committed the promised changes to the LCF Solr output connector.

ACL metadata will now be posted to the Solr Http interface along with the document as the
two following fields:


There will, of course, potentially be multiple values for each of these two fields.

Hope this helps,

From: ext Peter Sturge []
Sent: Tuesday, April 20, 2010 6:51 PM
Subject: Re: FW: Solr and LCF security at query time

Hi Karl,

Thanks for the info. I'll have a look at the link and try to take in as much sugar as my insulin
levels will handle...
It sounds like the necessary interface(s) are already in LCF - just a matter of implementing
them in the Solr 1872 plugin.
I'll need to digest the LCF stuff to get to grips with it..please bear with me while I do

When you say:
   The LCF solr output connection doesn't yet do this, but it is trivial for me to make that
Do you mean a mechanism by which solr.war can get url et al info from its parent container
(Tomcat, Jetty etc.), or have I misinterpreted this?


On Tue, Apr 20, 2010 at 11:05 PM, <<>>
Hi Peter,

I'm the principal committer for LCF, but I don't know as much about Solr as I ought to, so
it sounds like a potentially productive collaboration.

LCF does exactly what you are looking for - the only issue at all is that you need to fetch
a URL from a webapp to get what you are looking for.  The "plugs" are all inside LCF for different
kinds of repositories.  Here's a link that might help with drinking the LCF "koolaid", as
it were:

The url would be something like this (on a locally installed tomcat-based LCF instance):


... and this fetch returns something like:


... which represent the amalgamated tokens for all of the defined authorities, and by some
strange coincidence ( ;-) ) are compatible with certain pieces of metadata that have been
passed into Solr with each document - one set of Allow tokens, and a second set of Deny tokens.
 The LCF solr output connection doesn't yet do this, but it is trivial for me to make that

Does this sound plausible to you?


From: ext Peter Sturge [<>]
Sent: Tuesday, April 20, 2010 5:41 PM

Subject: Re: FW: Solr and LCF security at query time

Hi Karl,

Integrating LCF to get external token support for SOLR-1872 sounds very interesting indeed.
I don't know anything about LCF, but one of the things I was planning for SOLR-1872 is to
make acl.xml (or rather its behaviour) 'pluggable' - i.e. it would just be one of a series
of plugins that could be used for obtaining back-end authentication information.

If you're good with LCF, perhaps we could work together to build this in. One of the first
things would be defining an interface that would be as easy as possible to plug LCF into.
Have you any suggestions/insight on this front?

Many thanks,

On Tue, Apr 20, 2010 at 4:08 PM, <<>>
SOLR-1872 looks exactly like what I was envisioning, from the search query perspective, although
instead of the acl xml file you specify LCF stipulates you would dynamically query the lcf-authority-service
servlet for the access tokens themselves.  That would get you support for AD, Documentum,
LiveLink, Meridio, and Memex for free. It seems likely that this component could be modified
to work with LCF with minor effort.

The missing component still seems to be AD authentication, which needs a solution.


From: ext Peter Sturge [<>]
Sent: Tuesday, April 20, 2010 10:44 AM
Subject: Re: FW: Solr and LCF security at query time

If you want to do this completely within Solr, have a look at:
SOLR-1834 and SOLR-1872. These use a SearchComponent plugin for Solr.


On Tue, Apr 20, 2010 at 1:25 PM, <<>>

From: Wright Karl (Nokia-S/Cambridge)
Sent: Tuesday, April 20, 2010 8:16 AM
To: '<>'
Cc: '<>'; '<>';
Subject: RE: Solr and LCF security at query time


Yes, I am aware of this ticket and contribution.  Luckily LCF establishes a powerful multi-repository
security model, even though it doesn't yet do the final step of enforcing that model at the
search end.  LCF allows you to define multiple authorities to operate against disparate repositories,
and use the appropriate authority to secure any given document.  The solr people are aware
of this design, which addresses the issues raised by SOLR-1834 very nicely.  However, as I
said before, time is a problem, and the work still needs to be done.

I suggest you read up on the actual security model of LCF, and perhaps experiment with that
and the SOLR-1834 contribution, to see if there is common ground.  One thing we've learned
at MetaCarta is that post-filtering for security purposes is expensive, and it is better to
modify the queries themselves to restrict the results, if possible.  I'm not sure which approach
SOLR-1834 takes, although it sounds like it might be the filtering approach.  Still, it would
be better than nothing.

Please let me know what you find out.


From: ext Dominique Bejean [<>]
Sent: Tuesday, April 20, 2010 8:03 AM
To: Wright Karl (Nokia-S/Cambridge)
Subject: Re: Solr and LCF security at query time


Thank you for your reply.

I made some research today and I found this :

Sorl security model have to be able to filter result list with items coming from various sources
at the same time (livelink, documentum, file system, ...). Big subject :)


Le 20/04/10 13:34,<> a écrit :
Hi Dominique,

At the moment, in order to enforce the LCF security model within Lucene/Solr, you will need
to build this functionality into whatever client you are using to display the Lucene search
results.  Specifically, you would need to take the following steps:

(1) Have your users access your search client through Apache.
(2) Use the Apache module mod_auth_kerb, combined with LCF's mod_authz_annotate, to cause
authorization HTTP headers to be transmitted to the client webapp.
(3) Have your client webapp alter whatever queries it is doing, to add an appropriate query
clause for each of the access tokens transmitted in the headers.

(This is how it is done at MetaCarta.)

Alternatively, you may find a way to do this completely with a web application under a Java
app server such as Tomcat.  I have not yet done the research to find out whether this is a
feasible alternative.  Effectively, what you need something like mod_auth_kerb to do is to
authenticate your user against Active Directory, or whomever the authenticator ought to be.
 JAAS may be helpful here.

There are, of course, intentions to fill out the missing pieces more completely and transparently
via a Solr search plugin and/or filter.  What has been lacking is time.  If you are in a position
to do development in this area, we're happy to have any assistance you might provide.

From: ext Dominique Bejean []
Sent: Tuesday, April 20, 2010 5:06 AM
Subject: Solr and LCF security at query time


I don't see in LCF wiki how Solr and LCF works together at query time in order to remove from
the result list the items the user is not allowed to access.

In, I just see
these sentences :

" Once all these documents and their access tokens are handed to the search engine, it is
the search engine's job to enforce security by excluding inappropriate documents from the
search results. For Lucene, this infrastructure is expected to be built on top of Lucene's
generic metadata abilities, but has not been implemented at this time."

I am not sure to understand. Does this mean that for the moment, it is not possible for Solr
to apply security by using an Authority Connector ?


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