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<div class="moz-cite-prefix">On 07/23/2013 12:54 PM, David Chadwick
wrote:<br>
</div>
<blockquote cite="mid:51EEB53A.1070909@kent.ac.uk" type="cite">When
writing a previous ISO standard the approach we took was as
follows
<br>
<br>
Lie to people who are not authorised.
<br>
</blockquote>
<br>
Is that your verbage? I am going to reuse that quote, and I would
like to get the attribution correct.<br>
<br>
<blockquote cite="mid:51EEB53A.1070909@kent.ac.uk" type="cite">
<br>
So applying this approach to your situation, you could reply Not
Found to people who are authorised to see the object if it had
existed but does not, and Not Found to those not authorised to see
it, regardless of whether it exists or not. In this case, only
those who are authorised to see the object will get it if it
exists. Those not authorised cannot tell the difference between
objects that dont exist and those that do exist
<br>
</blockquote>
<br>
So, to try and apply this to a semi-real example: There are two
types of URLs. Ones that are like this:<br>
<br>
users/55FEEDBABECAFE<br>
<br>
and ones like this:<br>
<br>
domain/66DEADBEEF0000/users/55FEEDBABECAFE<br>
<br>
<br>
In the first case, you are selecting against a global collection,
and in the second, against a scoped collection.<br>
<br>
For unscoped, you have to treat all users as equal, and thus a 404
probably makes sense.<br>
<br>
For a scoped collection we could return a 404 or a <a
href="https://en.wikipedia.org/wiki/HTTP_403" title="HTTP 403">403
Forbidden</a> based on the users credentials: all resources under
domain/66DEADBEEF0000 would show up as 403s regardless of
existantce or not if the user had no roles in the domain
66DEADBEEF0000. A user that would be allowed access to resources in
66DEADBEEF0000 would get a 403 only for an object that existed but
that they had no permission to read, and 404 for a resource that
doesn't exist.<br>
<br>
<br>
<br>
<br>
<blockquote cite="mid:51EEB53A.1070909@kent.ac.uk" type="cite">
<br>
regards
<br>
<br>
David
<br>
<br>
<br>
On 23/07/2013 16:40, Henry Nash wrote:
<br>
<blockquote type="cite">Hi
<br>
<br>
As part of bp
<a class="moz-txt-link-freetext" href="https://blueprints.launchpad.net/keystone/+spec/policy-on-api-target">https://blueprints.launchpad.net/keystone/+spec/policy-on-api-target</a>
I have uploaded some example WIP code showing a proposed
approach for just a few API calls (one easy, one more complex).
I'd appreciate early feedback on this before I take it any
further.
<br>
<br>
<a class="moz-txt-link-freetext" href="https://review.openstack.org/#/c/38308/">https://review.openstack.org/#/c/38308/</a>
<br>
<br>
A couple of points:
<br>
<br>
- One question is on how to handle errors when you are going to
get a target object before doing you policy check. What do you
do if the object does not exist? If you return NotFound, then
someone, who was not authorized could troll for the existence
of entities by seeing whether they got NotFound or Forbidden.
If however, you return Forbidden, then users who are authorized
to, say, manage users in a domain would aways get Forbidden for
objects that didn't exist (since we can know where the
non-existant object was!). So this would modify the expected
return codes.
<br>
<br>
- I really think we need some good documentation on how to bud
keystone policy files. I'm happy to take a first cut as such a
thing - what do you think the right place is for such
documentation
<br>
<br>
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<br>
<br>
</blockquote>
<br>
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</blockquote>
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