I found that multiple membership grants added in v16 affects the
information_schema.applicable_roles view.
Examples on a master, but they works for v16 too.
Setup multiple membership alice in bob:
postgres@postgres(17.0)=# \drg alice
List of role grants
Role name | Member of | Options | Grantor
-----------+-----------+--------------+----------
alice | bob | INHERIT, SET | alice
alice | bob | INHERIT, SET | charlie
alice | bob | ADMIN | postgres
(3 rows)
The application_roles view shows duplicates:
postgres@postgres(17.0)=# SELECT * FROM
information_schema.applicable_roles WHERE grantee = 'alice';
grantee | role_name | is_grantable
---------+-----------+--------------
alice | bob | NO
alice | bob | YES
(2 rows)
View definition:
postgres@postgres(17.0)=# \sv information_schema.applicable_roles
CREATE OR REPLACE VIEW information_schema.applicable_roles AS
SELECT a.rolname::information_schema.sql_identifier AS grantee,
b.rolname::information_schema.sql_identifier AS role_name,
CASE
WHEN m.admin_option THEN 'YES'::text
ELSE 'NO'::text
END::information_schema.yes_or_no AS is_grantable
FROM ( SELECT pg_auth_members.member,
pg_auth_members.roleid,
pg_auth_members.admin_option
FROM pg_auth_members
UNION
SELECT pg_database.datdba,
pg_authid.oid,
false
FROM pg_database,
pg_authid
WHERE pg_database.datname = current_database() AND
pg_authid.rolname = 'pg_database_owner'::name) m
JOIN pg_authid a ON m.member = a.oid
JOIN pg_authid b ON m.roleid = b.oid
WHERE pg_has_role(a.oid, 'USAGE'::text);
I think that only one row with admin option should be returned.
This can be achieved by adding group by + bool_or to the inner select
from pg_auth_members.
BEGIN;
BEGIN
postgres@postgres(17.0)=*# CREATE OR REPLACE VIEW
information_schema.applicable_roles AS
SELECT a.rolname::information_schema.sql_identifier AS grantee,
b.rolname::information_schema.sql_identifier AS role_name,
CASE
WHEN m.admin_option THEN 'YES'::text
ELSE 'NO'::text
END::information_schema.yes_or_no AS is_grantable
FROM ( SELECT pg_auth_members.member,
pg_auth_members.roleid,
bool_or(pg_auth_members.admin_option) AS admin_option
FROM pg_auth_members
GROUP BY 1, 2
UNION
SELECT pg_database.datdba,
pg_authid.oid,
false
FROM pg_database,
pg_authid
WHERE pg_database.datname = current_database() AND
pg_authid.rolname = 'pg_database_owner'::name) m
JOIN pg_authid a ON m.member = a.oid
JOIN pg_authid b ON m.roleid = b.oid
WHERE pg_has_role(a.oid, 'USAGE'::text);
CREATE VIEW
postgres@postgres(17.0)=*# SELECT * FROM
information_schema.applicable_roles WHERE grantee = 'alice';
grantee | role_name | is_grantable
---------+-----------+--------------
alice | bob | YES
(1 row)
postgres@postgres(17.0)=*# ROLLBACK;
ROLLBACK
Should we add group by + bool_or to the applicable_roles view?
--
Pavel Luzanov
Postgres Professional: https://postgrespro.com
