[Go-essp-tech] resolution on securing opendap aggregations via ESGF
Sébastien Denvil
sebastien.denvil at ipsl.jussieu.fr
Wed May 25 05:03:11 MDT 2011
On 24/05/2011 12:01, stephen.pascoe at stfc.ac.uk wrote:
>
> IMHO CIM is a red herring. Why would we want to put a CIM simulation
> record (a substantial chunk of XML) into every single THREDDS
> catalog? That would be extreme database denormalisation.
>
> QC data could be more feasible. However, what if data from datanode A
> is replicated to DKRZ, they do QC L2 and find it doesn't pass. How is
> this communicated?
>
For each modelling group you need 2 specific contacts to communicate
this information (2 people because you need redundancy here).
> Do we ask datanode A to republish saying their data is bad?
>
Yes.
> Will they do it?
>
It's very likely that : yes.
> Even without this human problem keeping QC information consistent
> across replicas will become a headache.
>
It looks like we are missing tools here.
Regards.
Sébastien
> S.
>
> ---
>
> Stephen Pascoe +44 (0)1235 445980
>
> Centre of Environmental Data Archival
>
> STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, UK
>
> *From:* Estanislao Gonzalez [mailto:gonzalez at dkrz.de]
> *Sent:* 24 May 2011 08:59
> *To:* Gavin M. Bell
> *Cc:* Pascoe, Stephen (STFC,RAL,RALSP); Luca.Cinquini at jpl.nasa.gov;
> go-essp-tech at ucar.edu
> *Subject:* Re: [Go-essp-tech] resolution on securing opendap
> aggregations via ESGF
>
> Hi,
>
> just to be more precise: indeed I think security and CIM data
> (meta-data from experiments and so on) should be kept away from the
> catalogs.
>
> Still, Luca's idea of merging QC level info with the files itself
> might be a valid idea. The difference is that QC is pretty much like a
> "semantic" checksum for a file. AFAIK you cannot "downgrade" the QC
> without altering the file, i.e. if the file is QC L2 and while
> performing QC L3 checks an error is found, the file will either be QC
> L3 approved (the modeler defines the "oddity" as "expected") or it
> doesn't, which implies a "QC L2 passed; QC L3 failed" flag or the
> retraction (and maybe re-publication) of it altogether.
>
> Well, that's at least why I think the QC flag is a little different
> and it's *closely* related to the file. The only difference with the
> checksum is IMHO that it takes more time to be determined (as well as
> require other files for it's computation) and thus it's performed in
> an out-of-band fashion.
>
> We need that QC flag somewhere... and it's far more important than the
> rest of the CIM meta-data (getting back to Gavin's point about CIM
> issues and differentiating it to this QC flag: yes, you can still get
> to the file and download it without CIM data... but without the QC
> flag you'll have no clue if you *really* want to rely on this data).
>
> To be honest I can't understand why people download this data if they
> *know* it might get corrected. Would you start writing a paper on
> something that might be altogether wrong?... I suspect they don't
> realize this.
>
> Anyway, my 2c...
>
> Thanks,
> Estani
>
> Am 24.05.2011 03:06, schrieb Gavin M. Bell:
>
> Hi Luca,
>
> I think that the separation of concerns trumps the apparent
> "simplicity". Though it is apparently easy to republish (I am not
> sure I fully agree with that, at least not from the anecdotal
> information I hear from folks)... it is unnecessary to publish if we
> keep concerns separated.
>
> As Estani said, the publisher publishes and does basic mechanical
> sanity checks on data. That should be the full extent of its
> operation. As far as what is easy... one could 'easily' set up an
> index over the CIM info and "join" on datasetid. This also provides
> loose coupling. If the CIM system has issues, that just means that
> when you look at your search results you won't see CIM info, but you
> will still see the dataset and be able to fetch and manipulate it and
> everything else. Also if the CIM changes it doesn't affect the
> pubblisher or publishing in any way. Catalogs should be viewed as
> "files" in the system... they essentially are logical files
> (containing pointers to physical files).
>
> I am still not convinced by your arguments that fusing and coupling
> these two semantically different aspects of the system so tightly is
> the right long term architectural solution. It may be good now, but
> it not as flexible later. We should leave open the avenue for other
> meta-metadata to be imbued onto our system ex-post-facto without much ado.
>
> my $0.02
>
> On 5/23/11 2:08 AM, stephen.pascoe at stfc.ac.uk
> <mailto:stephen.pascoe at stfc.ac.uk> wrote:
>
> I'm with Estani on this. Authorisation decisions are best decoupled from the application where possible. Phil is on leave today but I'm sure he'd say the same thing and give much more detailed reasoning.
>
> I think the catalogue already mixes slightly too much information together: location-independent file metadata and location-specific service information. If we add access control it becomes too tightly coupled.
>
> Stephen.
>
> ---
> Stephen Pascoe +44 (0)1235 445980
> Centre of Environmental Data Archival
> STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, UK
>
>
> -----Original Message-----
> From:go-essp-tech-bounces at ucar.edu <mailto:go-essp-tech-bounces at ucar.edu> [mailto:go-essp-tech-bounces at ucar.edu] On Behalf Of Estanislao Gonzalez
> Sent: 21 May 2011 09:30
> To: Cinquini, Luca (3880)
> Cc:go-essp-tech at ucar.edu <mailto:go-essp-tech at ucar.edu>
> Subject: Re: [Go-essp-tech] resolution on securing opendap aggregations via ESGF
>
> Hi,
>
> In my opinion we shouldn't encode the access restriction in the catalog
> for these reasons:
> 1) Changing the access would involved re-publishing the files. (this
> will be done for instance when QC L2 is reached CMIP5 Research -> CMIP5
> Commercial). And think about what would happen if we want to change the
> access restriction in a couple of years... we should publish everything
> again, and that would involve quite some effort to understand the
> procedure again...
> 2) I'm not sure of this, but I fear TDS security cannot handle multiple
> roles. Right now you can publish to as many roles as required, and read
> and write access is kept separately. This would involve extending the
> TDS capabilities.
> 3) There could be potential inconsistencies if the authorization service
> is detached from datanode (like with the gateway right now) and the
> publisher alters the role but forgets to cascade the changes to the
> authorizing service (which would proceed according to the last harvested
> info)
> 4) And last but not least, I'm not sure we want to mix administration
> with publication. The publisher should only care about making data
> available, the administrator should organize this and be responsible for
> the security.
>
> So basically I don't agree :-) Although I do think, if required, we
> could change "esg-user" for "esgf-controlled" if it's more intuitive.
>
> My 2c anyways,
> Estani
>
> Am 20.05.2011 19:17, schrieb Cinquini, Luca (3880):
>
> Hi,
>
> a few points again on the issue of securing opendap aggregations served by the TDS with ESGF filters:
>
>
>
> o There's a new release of the ESGF security filters (esg-orp 1.1.2) that maps the TDS request URI to the dataset ID, and should solve this problem. You can experiment with the JPL test TDS server:
>
>
>
> http://test-datanode.jpl.nasa.gov/thredds/catalog.html
>
>
>
> where the AIRS dataset (and aggregations) is secured, the MLS is not.
>
>
>
> o Now the data node authorization filter will correctly identify the aggregation as secured, and call the configured authorization service. Currently, the p2p Node authorization service can be configured to allow authorization based on URL matching, so it will work. The gateway authorization service will have to implement its own logic to establish authorization.
>
>
>
> o Finally, I am wondering if we shouldn't change the way we encode authorization in thredds catalogs. Right now, we use restrictAccess="esg-user" for ALL collections, but should we consider about encoding the proper required access control attribute instead, for example restrictAccess="CMIP5 Research" ? Something to think about - there are prons and cons about this - it's all a question on wether the access control belongs in the catalog (and can be harvested for searching...) or not.
>
>
>
> thanks, Luca
>
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>
> --
> Gavin M. Bell
> --
>
> "Never mistake a clear view for a short distance."
> -Paul Saffo
>
>
>
>
>
> --
> Estanislao Gonzalez
>
> Max-Planck-Institut für Meteorologie (MPI-M)
> Deutsches Klimarechenzentrum (DKRZ) - German Climate Computing Centre
> Room 108 - Bundesstrasse 45a, D-20146 Hamburg, Germany
>
> Phone: +49 (40) 46 00 94-126
> E-Mail:gonzalez at dkrz.de <mailto:gonzalez at dkrz.de>
>
> --
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--
Sébastien Denvil
IPSL, Pôle de modélisation du climat
UPMC, Case 101, 4 place Jussieu,
75252 Paris Cedex 5
Tour 45-55 2ème étage Bureau 209
Tel: 33 1 44 27 21 10
Fax: 33 1 44 27 39 02
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