Suggest a pg_privileges table

I would like to suggest the following augmentation to the PostgreSQL DBMS.
This augmentation is to add a pg_privileges table for each database instance.
Such a table should be responsible for maintaining the SELECT, UPDATE, INSERT,
and DELETE permissions on all database objects.  Furthermore, it should maintain
other privileges such as the CREATE DATABASE, CREATE USER, DESTROY USER,
CREATE TABLE, and the list goes on.  One other benefit this would bring would be
to allow the setting of privileges on table columns.  This would alleviate
the question of creating a separte relation for holding passwords rather than
keeping this info in pg_user (Simply make the password field non-selectable by
public).

I don't know that I can volunteer to perform all the changes this would involve,
but I would be very willing to help, as this would greatly improve the security
of PostgreSQL.

If anyone has any comments or concerns about such a project, let me know.  Suuch a
system should be crafted with care.  I would like to reach a consensus among the
hacker community before I begin to make any mods to bring this about.

I see the changes taking place in the following order:

1)  Code the creation of pg_privileges.
2)  Make sure the initial permissions of database instance object are in the
    pg_privileges relation upon database creation.
3)  Rewrite the GRANT and REVOKE statements to update pg_privileges, and (this
    must be done at the same time) supplant the old privileges system.  This
    would give us table privileges as they are now.
4-Infinity) Begin adding new privileges such as CREATE USER, CREATE DATABASE,
            CREATE TABLE, DESTROY TABLE, etc to the system.

This is a very coarse view of how to accomplish this task.  Also, I left out
column privileges.  This should probably be listed at (3.5) above.

Let me know what you think (If you send a reply to the pgsql-hackers email
account, please be certain to cc me also).  I will pull all the comments
together and start to create a requirements document for pg_privileges.

Todd A. Brandys
brandys@eng3.hep.uiuc.edu