Hello

On 2020-05-25 15:50, Laurenz Albe wrote:
On Fri, 2020-05-22 at 08:02 -0500, Ted Toth wrote:
Will RLS be applied to data being retrieved via a FDW?

ALTER FOREIGN TABLE rp_2019 ENABLE ROW LEVEL SECURITY;
ERROR:  "rp_2019" is not a table

Doesn't look good.

Yours,
Laurenz Albe

Actually it does work if you set the policy on the source table and access it using the user defined in the user mappings on the foreign table on the remote server.

Server 1:

charles@kofdb.archivedb.5432=# \d public.test_fdw_rls
             Table "public.test_fdw_rls"
  Column  |  Type   | Collation | Nullable | Default
----------+---------+-----------+----------+---------
 id       | integer |           |          |
 content  | text    |           |          |
 username | text    |           |          |
Policies:
    POLICY "kofadmin_select" FOR SELECT
      TO kofadmin
      USING ((username = ("current_user"())::text))

kofadmin@kofdb.archivedb.5432=> \dp public.test_fdw_rls
                                                     Access privileges
Schema | Name | Type | Access privileges | Column privileges | Policies
--------+--------------+-------+-------------------------+-------------------+----------------------------------------------
public | test_fdw_rls | table | charles=arwdDxt/charles+| | kofadmin_select (r): + | | | kofadmin=arwd/charles | | (u): (username = ("current_user"())::text)+ | | | | | to: kofadmin

charles@kofdb.archivedb.5432=# SELECT CURRENT_USER; SELECT * FROM public.test_fdw_rls;

charles@kofdb.archivedb.5432=# SELECT CURRENT_USER; SELECT * FROM public.test_fdw_rls;
 current_user
--------------
 charles
(1 row)

 id |             content              | username
----+----------------------------------+----------
  1 | Text for charles                 | charles
  1 | Access from fdw via user fdwsync | fdwsync
(2 rows)

charles@kofdb.archivedb.5432=# set role fdwsync ;
SET
charles@kofdb.archivedb.5432=> SELECT CURRENT_USER; SELECT * FROM public.test_fdw_rls;
 current_user
--------------
 fdwsync
(1 row)

 id |             content              | username
----+----------------------------------+----------
  1 | Access from fdw via user fdwsync | fdwsync
(1 row)

On the server accessing the table via FDW:

kofadmin@kofdb.t-archivedb.5432=> \deu+
                        List of user mappings
   Server   | User name |                 FDW options
------------+-----------+---------------------------------------------
 kofdb_prod | kofadmin  | (password 'mysecret', "user" 'fdwsync')

kofadmin@kofdb.t-archivedb.5432=> SELECT CURRENT_USER; SELECT * FROM public.test_fdw_rls ;
 current_user
--------------
 kofadmin
(1 row)

 id |             content              | username
----+----------------------------------+----------
  1 | Access from fdw via user fdwsync | fdwsync
(1 row)

Regards
Charles


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