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Re: Prep object creation hooks, and related sepgsql updates

From: Kohei KaiGai <kaigai(at)kaigai(dot)gr(dot)jp>
To: Dimitri Fontaine <dimitri(at)2ndquadrant(dot)fr>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, PgHacker <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Prep object creation hooks, and related sepgsql updates
Date: 2011-11-28 14:16:23
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Lists: pgsql-hackers
2011/11/27 Dimitri Fontaine <dimitri(at)2ndquadrant(dot)fr>:
>> And, it seems to me the current proposition of the command trigger
>> does not support to fire triggers on creation of databases, although
>> permission checks requires Oid of source database that is not also
>> appeared in pg_database catalog.
> I have to have a look at what forbids us to add support for the create
> database command here.  It seems to be just another branch of the switch
> in standard_ProcessUtility().
I'm not sure what arguments shall be provided to the guest of command
triggers. And, I'd like to mention about its specification should not depend
on details of particular modules; according to the previous discussion.

After the long discussion, one concensus is that prep-creation hook shall
be deployed around existing DAC checks and it takes arguments that are
also referenced at the existing DAC; such as oid of source database on
creation of databases.
I also checked security model between DAC and MAC, and I concluded
most of them takes common information to make its decision.

It is a hard to answer question whether we can implement sepgsql on the
upcoming command trigger feature; without information about where its
hooks shall be deployed and what arguments are provided. :-(

>>> I don't think schemaname+objectname fails to be unique, so I don't think
>>> you need another kind of Oid in BEFORE creation triggers here.
>> The pg_seclabel and pg_shseclabel needs OID to assign a security label
>> on a particular database object, so label provider (sepgsql) must know
>> Oid of the target object on assignment time.
> Yes, and you need to refer to things you did in the BEFORE trigger from
> the AFTER trigger, I'm just offering you a way to do that.  Then if you
> need the Oid in the AFTER trigger, of course you have it.
How does it inherit an opaque private initialized at BEFORE trigger to
AFTER trigger? I checked your patch, however, it seems to me it does
not have a mechanism to deliver something between BEFORE and AFTER.

KaiGai Kohei <kaigai(at)kaigai(dot)gr(dot)jp>

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