Re: PG 16 draft release notes ready

On Thu, Aug 17, 2023 at 08:37:28AM +0300, Pavel Luzanov wrote:
> On 17.08.2023 05:36, Bruce Momjian wrote:
> > On Wed, Aug 9, 2023 at 08:35:21PM -0400, Bruce Momjian wrote:
> > > On Sat, Aug 5, 2023 at 04:08:47PM -0700, Noah Misch wrote:
> > > > > Author: Robert Haas <rhaas(at)postgresql(dot)org>
> > > > > 2022-08-25 [e3ce2de09] Allow grant-level control of role inheritance behavior.
> > > > > -->
> > > > >
> > > > > <listitem>
> > > > > <para>
> > > > > Allow GRANT to control role inheritance behavior (Robert Haas)
> > > > > </para>
> > > > >
> > > > > <para>
> > > > > By default, role inheritance is controlled by the inheritance status of the member role. The new GRANT clauses WITH INHERIT and WITH ADMIN can now override this.
> > > > > </para>
> > > > > </listitem>
> > > > >
> > > > > <!--
> > > > > Author: Robert Haas <rhaas(at)postgresql(dot)org>
> > > > > 2023-01-10 [e5b8a4c09] Add new GUC createrole_self_grant.
> > > > > Author: Daniel Gustafsson <dgustafsson(at)postgresql(dot)org>
> > > > > 2023-02-22 [e00bc6c92] doc: Add default value of createrole_self_grant
> > > > > -->
> > > > >
> > > > > <listitem>
> > > > > <para>
> > > > > Allow roles that create other roles to automatically inherit the new role's rights or SET ROLE to the new role (Robert Haas, Shi Yu)
> > > > > </para>
> > > > >
> > > > > <para>
> > > > > This is controlled by server variable createrole_self_grant.
> > > > > </para>
> > > > > </listitem>
> > > > Similarly, v16 radically changes the CREATE ROLE ... WITH INHERIT clause. The
> > > > clause used to "change the behavior of already-existing grants." Let's merge
> > > > these two and move the combination to the incompatibilities section.
> > > I need help with this. I don't understand how they can be combined, and
> > > I don't understand the incompatibility text in commit e3ce2de09d:
> > >
> > > If a GRANT does not specify WITH INHERIT, the behavior based on
> > > whether the member role is marked INHERIT or NOINHERIT. This means
> > > that if all roles are marked INHERIT or NOINHERIT before any role
> > > grants are performed, the behavior is identical to what we had before;
> > > otherwise, it's different, because ALTER ROLE [NO]INHERIT now only
> > > changes the default behavior of future grants, and has no effect on
> > > existing ones.
> > I am waiting for an answer to this question, or can I assume the release
> > notes are acceptable?
>
> I can try to explain how I understand it myself.
>
> In v15 and early, inheritance of granted to role privileges depends on
> INHERIT attribute of a role:
>
> create user alice;
> grant pg_read_all_settings to alice;
>
> By default privileges inherited:
> \c - alice
> show data_directory;
>        data_directory
> -----------------------------
>  /var/lib/postgresql/15/main
> (1 row)
>
> After disabling the INHERIT attribute, privileges are not inherited:
>
> \c - postgres
> alter role alice noinherit;
>
> \c - alice
> show data_directory;
> ERROR:  must be superuser or have privileges of pg_read_all_settings to
> examine "data_directory"
>
> In v16 changing INHERIT attribute on alice role doesn't change inheritance
> behavior of already granted roles.
> If we repeat the example, Alice still inherits pg_read_all_settings
> privileges after disabling the INHERIT attribute for the role.
>
> Information for making decisions about role inheritance has been moved from
> the role attribute to GRANT role TO role [WITH INHERIT|NOINHERIT] command
> and can be viewed by the new \drg command:
>
> \drg
>                     List of role grants
>  Role name |      Member of       |   Options    | Grantor
> -----------+----------------------+--------------+----------
>  alice     | pg_read_all_settings | INHERIT, SET | postgres
> (1 row)
>
> Changing the INHERIT attribute for a role now will affect (as the default
> value) only future GRANT commands without an INHERIT clause.

I was able to create this simple example to illustrate it:

CREATE ROLE a1;
CREATE ROLE a2;
CREATE ROLE a3;
CREATE ROLE a4;
CREATE ROLE b INHERIT;

GRANT a1 TO b WITH INHERIT TRUE;
GRANT a2 TO b WITH INHERIT FALSE;

GRANT a3 TO b;
ALTER USER b NOINHERIT;
GRANT a4 TO b;

\drg
List of role grants
Role name | Member of | Options | Grantor
-----------+-----------+--------------+----------
b | a1 | INHERIT, SET | postgres
b | a2 | SET | postgres
b | a3 | INHERIT, SET | postgres
b | a4 | SET | postgres

I will work on the relase notes adjustments for this and reply in a few
days.

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

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