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Add "pg_database_owner" default role.
Membership consists, implicitly, of the current database owner. Expect use in template databases. Once pg_database_owner has rights within a template, each owner of a database instantiated from that template will exercise those rights. Reviewed by John Naylor. Discussion: https://postgr.es/m/[email protected]
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11 files changed

+207
-6
lines changed

11 files changed

+207
-6
lines changed

‎doc/src/sgml/catalogs.sgml

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -10138,6 +10138,9 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
1013810138
<primary>pg_group</primary>
1013910139
</indexterm>
1014010140

10141+
<!-- Unlike information_schema.applicable_roles, this shows no members for
10142+
pg_database_owner. The v8.1 catalog would have shown no members if
10143+
that role had existed at the time. -->
1014110144
<para>
1014210145
The view <structname>pg_group</structname> exists for backwards
1014310146
compatibility: it emulates a catalog that existed in

‎doc/src/sgml/user-manag.sgml

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -540,6 +540,10 @@ DROP ROLE doomed_role;
540540
<literal>pg_read_all_stats</literal> and
541541
<literal>pg_stat_scan_tables</literal>.</entry>
542542
</row>
543+
<row>
544+
<entry>pg_database_owner</entry>
545+
<entry>None. Membership consists, implicitly, of the current database owner.</entry>
546+
</row>
543547
<row>
544548
<entry>pg_signal_backend</entry>
545549
<entry>Signal another backend to cancel a query or terminate its session.</entry>
@@ -572,6 +576,17 @@ DROP ROLE doomed_role;
572576
other system information normally restricted to superusers.
573577
</para>
574578

579+
<para>
580+
The <literal>pg_database_owner</literal> role has one implicit,
581+
situation-dependent member, namely the owner of the current database. The
582+
role conveys no rights at first. Like any role, it can own objects or
583+
receive grants of access privileges. Consequently, once
584+
<literal>pg_database_owner</literal> has rights within a template database,
585+
each owner of a database instantiated from that template will exercise those
586+
rights. <literal>pg_database_owner</literal> cannot be a member of any
587+
role, and it cannot have non-implicit members.
588+
</para>
589+
575590
<para>
576591
The <literal>pg_signal_backend</literal> role is intended to allow
577592
administrators to enable trusted, but non-superuser, roles to send signals

‎src/backend/catalog/information_schema.sql

Lines changed: 8 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -255,7 +255,14 @@ CREATE VIEW applicable_roles AS
255255
SELECT CAST(a.rolname AS sql_identifier) AS grantee,
256256
CAST(b.rolname AS sql_identifier) AS role_name,
257257
CAST(CASE WHEN m.admin_option THEN 'YES' ELSE 'NO' END AS yes_or_no) AS is_grantable
258-
FROM pg_auth_members m
258+
FROM (SELECT member, roleid, admin_option FROM pg_auth_members
259+
-- This UNION could be UNION ALL, but UNION works even if we start
260+
-- to allow explicit pg_database_owner membership.
261+
UNION
262+
SELECT datdba, pg_authid.oid, false
263+
FROM pg_database, pg_authid
264+
WHERE datname = current_database() AND rolname = 'pg_database_owner'
265+
) m
259266
JOIN pg_authid a ON (m.member = a.oid)
260267
JOIN pg_authid b ON (m.roleid = b.oid)
261268
WHERE pg_has_role(a.oid, 'USAGE');

‎src/backend/commands/user.c

Lines changed: 36 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1496,6 +1496,18 @@ AddRoleMems(const char *rolename, Oid roleid,
14961496
rolename)));
14971497
}
14981498

1499+
/*
1500+
* The charter of pg_database_owner is to have exactly one, implicit,
1501+
* situation-dependent member. There's no technical need for this
1502+
* restriction. (One could lift it and take the further step of making
1503+
* pg_database_ownercheck() equivalent to has_privs_of_role(roleid,
1504+
* DEFAULT_ROLE_DATABASE_OWNER), in which case explicit,
1505+
* situation-independent members could act as the owner of any database.)
1506+
*/
1507+
if (roleid == DEFAULT_ROLE_DATABASE_OWNER)
1508+
ereport(ERROR,
1509+
errmsg("role \"%s\" cannot have explicit members", rolename));
1510+
14991511
/*
15001512
* The role membership grantor of record has little significance at
15011513
* present. Nonetheless, inasmuch as users might look to it for a crude
@@ -1524,6 +1536,30 @@ AddRoleMems(const char *rolename, Oid roleid,
15241536
bool new_record_nulls[Natts_pg_auth_members];
15251537
bool new_record_repl[Natts_pg_auth_members];
15261538

1539+
/*
1540+
* pg_database_owner is never a role member. Lifting this restriction
1541+
* would require a policy decision about membership loops. One could
1542+
* prevent loops, which would include making "ALTER DATABASE x OWNER
1543+
* TO proposed_datdba" fail if is_member_of_role(pg_database_owner,
1544+
* proposed_datdba). Hence, gaining a membership could reduce what a
1545+
* role could do. Alternately, one could allow these memberships to
1546+
* complete loops. A role could then have actual WITH ADMIN OPTION on
1547+
* itself, prompting a decision about is_admin_of_role() treatment of
1548+
* the case.
1549+
*
1550+
* Lifting this restriction also has policy implications for ownership
1551+
* of shared objects (databases and tablespaces). We allow such
1552+
* ownership, but we might find cause to ban it in the future.
1553+
* Designing such a ban would more troublesome if the design had to
1554+
* address pg_database_owner being a member of role FOO that owns a
1555+
* shared object. (The effect of such ownership is that any owner of
1556+
* another database can act as the owner of affected shared objects.)
1557+
*/
1558+
if (memberid == DEFAULT_ROLE_DATABASE_OWNER)
1559+
ereport(ERROR,
1560+
errmsg("role \"%s\" cannot be a member of any role",
1561+
get_rolespec_name(memberRole)));
1562+
15271563
/*
15281564
* Refuse creation of membership loops, including the trivial case
15291565
* where a role is made a member of itself. We do this by checking to

‎src/backend/utils/adt/acl.c

Lines changed: 42 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -22,6 +22,7 @@
2222
#include "catalog/pg_auth_members.h"
2323
#include "catalog/pg_authid.h"
2424
#include "catalog/pg_class.h"
25+
#include "catalog/pg_database.h"
2526
#include "catalog/pg_type.h"
2627
#include "commands/dbcommands.h"
2728
#include "commands/proclang.h"
@@ -68,6 +69,7 @@ enum RoleRecurseType
6869
};
6970
static Oid cached_role[] = {InvalidOid, InvalidOid};
7071
static List *cached_roles[] = {NIL, NIL};
72+
static uint32 cached_db_hash;
7173

7274

7375
static const char *getid(const char *s, char *n);
@@ -4665,17 +4667,24 @@ initialize_acl(void)
46654667
{
46664668
if (!IsBootstrapProcessingMode())
46674669
{
4670+
cached_db_hash =
4671+
GetSysCacheHashValue1(DATABASEOID,
4672+
ObjectIdGetDatum(MyDatabaseId));
4673+
46684674
/*
46694675
* In normal mode, set a callback on any syscache invalidation of rows
4670-
* of pg_auth_members (for roles_is_member_of()) or pg_authid (for
4671-
* has_rolinherit())
4676+
* of pg_auth_members (for roles_is_member_of()), pg_authid (for
4677+
* has_rolinherit()), or pg_database (for roles_is_member_of())
46724678
*/
46734679
CacheRegisterSyscacheCallback(AUTHMEMROLEMEM,
46744680
RoleMembershipCacheCallback,
46754681
(Datum) 0);
46764682
CacheRegisterSyscacheCallback(AUTHOID,
46774683
RoleMembershipCacheCallback,
46784684
(Datum) 0);
4685+
CacheRegisterSyscacheCallback(DATABASEOID,
4686+
RoleMembershipCacheCallback,
4687+
(Datum) 0);
46794688
}
46804689
}
46814690

@@ -4686,6 +4695,13 @@ initialize_acl(void)
46864695
static void
46874696
RoleMembershipCacheCallback(Datum arg, int cacheid, uint32 hashvalue)
46884697
{
4698+
if (cacheid == DATABASEOID &&
4699+
hashvalue != cached_db_hash &&
4700+
hashvalue != 0)
4701+
{
4702+
return; /* ignore pg_database changes for other DBs */
4703+
}
4704+
46894705
/* Force membership caches to be recomputed on next use */
46904706
cached_role[ROLERECURSE_PRIVS] = InvalidOid;
46914707
cached_role[ROLERECURSE_MEMBERS] = InvalidOid;
@@ -4728,6 +4744,7 @@ static List *
47284744
roles_is_member_of(Oid roleid, enum RoleRecurseType type,
47294745
Oid admin_of, bool *is_admin)
47304746
{
4747+
Oid dba;
47314748
List *roles_list;
47324749
ListCell *l;
47334750
List *new_cached_roles;
@@ -4740,6 +4757,24 @@ roles_is_member_of(Oid roleid, enum RoleRecurseType type,
47404757
OidIsValid(cached_role[type]))
47414758
return cached_roles[type];
47424759

4760+
/*
4761+
* Role expansion happens in a non-database backend when guc.c checks
4762+
* DEFAULT_ROLE_READ_ALL_SETTINGS for a physical walsender SHOW command.
4763+
* In that case, no role gets pg_database_owner.
4764+
*/
4765+
if (!OidIsValid(MyDatabaseId))
4766+
dba = InvalidOid;
4767+
else
4768+
{
4769+
HeapTuple dbtup;
4770+
4771+
dbtup = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(MyDatabaseId));
4772+
if (!HeapTupleIsValid(dbtup))
4773+
elog(ERROR, "cache lookup failed for database %u", MyDatabaseId);
4774+
dba = ((Form_pg_database) GETSTRUCT(dbtup))->datdba;
4775+
ReleaseSysCache(dbtup);
4776+
}
4777+
47434778
/*
47444779
* Find all the roles that roleid is a member of, including multi-level
47454780
* recursion. The role itself will always be the first element of the
@@ -4787,6 +4822,11 @@ roles_is_member_of(Oid roleid, enum RoleRecurseType type,
47874822
roles_list = list_append_unique_oid(roles_list, otherid);
47884823
}
47894824
ReleaseSysCacheList(memlist);
4825+
4826+
/* implement pg_database_owner implicit membership */
4827+
if (memberid == dba && OidIsValid(dba))
4828+
roles_list = list_append_unique_oid(roles_list,
4829+
DEFAULT_ROLE_DATABASE_OWNER);
47904830
}
47914831

47924832
/*

‎src/backend/utils/cache/catcache.c

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1076,8 +1076,9 @@ InitCatCachePhase2(CatCache *cache, bool touch_index)
10761076
* criticalRelcachesBuilt), we don't have to worry anymore.
10771077
*
10781078
* Similarly, during backend startup we have to be able to use the
1079-
* pg_authid and pg_auth_members syscaches for authentication even if
1080-
* we don't yet have relcache entries for those catalogs' indexes.
1079+
* pg_authid, pg_auth_members and pg_database syscaches for
1080+
* authentication even if we don't yet have relcache entries for those
1081+
* catalogs' indexes.
10811082
*/
10821083
static bool
10831084
IndexScanOK(CatCache *cache, ScanKey cur_skey)
@@ -1110,6 +1111,7 @@ IndexScanOK(CatCache *cache, ScanKey cur_skey)
11101111
case AUTHNAME:
11111112
case AUTHOID:
11121113
case AUTHMEMMEMROLE:
1114+
case DATABASEOID:
11131115

11141116
/*
11151117
* Protect authentication lookups occurring before relcache has

‎src/bin/psql/describe.c

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3557,6 +3557,7 @@ describeRoles(const char *pattern, bool verbose, bool showSystem)
35573557

35583558
printTableAddHeader(&cont, gettext_noop("Role name"), true, align);
35593559
printTableAddHeader(&cont, gettext_noop("Attributes"), true, align);
3560+
/* ignores implicit memberships from superuser & pg_database_owner */
35603561
printTableAddHeader(&cont, gettext_noop("Member of"), true, align);
35613562

35623563
if (verbose && pset.sversion >= 80200)

‎src/include/catalog/catversion.h

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -53,6 +53,6 @@
5353
*/
5454

5555
/* yyyymmddN */
56-
#define CATALOG_VERSION_NO 202103264
56+
#define CATALOG_VERSION_NO 202103265
5757

5858
#endif

‎src/include/catalog/pg_authid.dat

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -24,6 +24,11 @@
2424
rolcreaterole => 't', rolcreatedb => 't', rolcanlogin => 't',
2525
rolreplication => 't', rolbypassrls => 't', rolconnlimit => '-1',
2626
rolpassword => '_null_', rolvaliduntil => '_null_' },
27+
{ oid => '8778', oid_symbol => 'DEFAULT_ROLE_DATABASE_OWNER',
28+
rolname => 'pg_database_owner', rolsuper => 'f', rolinherit => 't',
29+
rolcreaterole => 'f', rolcreatedb => 'f', rolcanlogin => 'f',
30+
rolreplication => 'f', rolbypassrls => 'f', rolconnlimit => '-1',
31+
rolpassword => '_null_', rolvaliduntil => '_null_' },
2732
{ oid => '3373', oid_symbol => 'DEFAULT_ROLE_MONITOR',
2833
rolname => 'pg_monitor', rolsuper => 'f', rolinherit => 't',
2934
rolcreaterole => 'f', rolcreatedb => 'f', rolcanlogin => 'f',

‎src/test/regress/expected/privileges.out

Lines changed: 61 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1719,6 +1719,67 @@ SELECT * FROM pg_largeobject LIMIT 0;
17191719
SET SESSION AUTHORIZATION regress_priv_user1;
17201720
SELECT * FROM pg_largeobject LIMIT 0; -- to be denied
17211721
ERROR: permission denied for table pg_largeobject
1722+
-- test pg_database_owner
1723+
RESET SESSION AUTHORIZATION;
1724+
GRANT pg_database_owner TO regress_priv_user1;
1725+
ERROR: role "pg_database_owner" cannot have explicit members
1726+
GRANT regress_priv_user1 TO pg_database_owner;
1727+
ERROR: role "pg_database_owner" cannot be a member of any role
1728+
CREATE TABLE datdba_only ();
1729+
ALTER TABLE datdba_only OWNER TO pg_database_owner;
1730+
REVOKE DELETE ON datdba_only FROM pg_database_owner;
1731+
SELECT
1732+
pg_has_role('regress_priv_user1', 'pg_database_owner', 'USAGE') as priv,
1733+
pg_has_role('regress_priv_user1', 'pg_database_owner', 'MEMBER') as mem,
1734+
pg_has_role('regress_priv_user1', 'pg_database_owner',
1735+
'MEMBER WITH ADMIN OPTION') as admin;
1736+
priv | mem | admin
1737+
------+-----+-------
1738+
f | f | f
1739+
(1 row)
1740+
1741+
BEGIN;
1742+
DO $$BEGIN EXECUTE format(
1743+
'ALTER DATABASE %I OWNER TO regress_priv_group2', current_catalog); END$$;
1744+
SELECT
1745+
pg_has_role('regress_priv_user1', 'pg_database_owner', 'USAGE') as priv,
1746+
pg_has_role('regress_priv_user1', 'pg_database_owner', 'MEMBER') as mem,
1747+
pg_has_role('regress_priv_user1', 'pg_database_owner',
1748+
'MEMBER WITH ADMIN OPTION') as admin;
1749+
priv | mem | admin
1750+
------+-----+-------
1751+
t | t | f
1752+
(1 row)
1753+
1754+
SET SESSION AUTHORIZATION regress_priv_user1;
1755+
TABLE information_schema.enabled_roles ORDER BY role_name COLLATE "C";
1756+
role_name
1757+
---------------------
1758+
pg_database_owner
1759+
regress_priv_group2
1760+
regress_priv_user1
1761+
(3 rows)
1762+
1763+
TABLE information_schema.applicable_roles ORDER BY role_name COLLATE "C";
1764+
grantee | role_name | is_grantable
1765+
---------------------+---------------------+--------------
1766+
regress_priv_group2 | pg_database_owner | NO
1767+
regress_priv_user1 | regress_priv_group2 | NO
1768+
(2 rows)
1769+
1770+
INSERT INTO datdba_only DEFAULT VALUES;
1771+
SAVEPOINT q; DELETE FROM datdba_only; ROLLBACK TO q;
1772+
ERROR: permission denied for table datdba_only
1773+
SET SESSION AUTHORIZATION regress_priv_user2;
1774+
TABLE information_schema.enabled_roles;
1775+
role_name
1776+
--------------------
1777+
regress_priv_user2
1778+
(1 row)
1779+
1780+
INSERT INTO datdba_only DEFAULT VALUES;
1781+
ERROR: permission denied for table datdba_only
1782+
ROLLBACK;
17221783
-- test default ACLs
17231784
\c -
17241785
CREATE SCHEMA testns;

‎src/test/regress/sql/privileges.sql

Lines changed: 31 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1034,6 +1034,37 @@ SELECT * FROM pg_largeobject LIMIT 0;
10341034
SET SESSION AUTHORIZATION regress_priv_user1;
10351035
SELECT * FROM pg_largeobject LIMIT 0; -- to be denied
10361036

1037+
-- test pg_database_owner
1038+
RESET SESSION AUTHORIZATION;
1039+
GRANT pg_database_owner TO regress_priv_user1;
1040+
GRANT regress_priv_user1 TO pg_database_owner;
1041+
CREATE TABLE datdba_only ();
1042+
ALTER TABLE datdba_only OWNER TO pg_database_owner;
1043+
REVOKE DELETE ON datdba_only FROM pg_database_owner;
1044+
SELECT
1045+
pg_has_role('regress_priv_user1', 'pg_database_owner', 'USAGE') as priv,
1046+
pg_has_role('regress_priv_user1', 'pg_database_owner', 'MEMBER') as mem,
1047+
pg_has_role('regress_priv_user1', 'pg_database_owner',
1048+
'MEMBER WITH ADMIN OPTION') as admin;
1049+
1050+
BEGIN;
1051+
DO $$BEGIN EXECUTE format(
1052+
'ALTER DATABASE %I OWNER TO regress_priv_group2', current_catalog); END$$;
1053+
SELECT
1054+
pg_has_role('regress_priv_user1', 'pg_database_owner', 'USAGE') as priv,
1055+
pg_has_role('regress_priv_user1', 'pg_database_owner', 'MEMBER') as mem,
1056+
pg_has_role('regress_priv_user1', 'pg_database_owner',
1057+
'MEMBER WITH ADMIN OPTION') as admin;
1058+
SET SESSION AUTHORIZATION regress_priv_user1;
1059+
TABLE information_schema.enabled_roles ORDER BY role_name COLLATE "C";
1060+
TABLE information_schema.applicable_roles ORDER BY role_name COLLATE "C";
1061+
INSERT INTO datdba_only DEFAULT VALUES;
1062+
SAVEPOINT q; DELETE FROM datdba_only; ROLLBACK TO q;
1063+
SET SESSION AUTHORIZATION regress_priv_user2;
1064+
TABLE information_schema.enabled_roles;
1065+
INSERT INTO datdba_only DEFAULT VALUES;
1066+
ROLLBACK;
1067+
10371068
-- test default ACLs
10381069
\c -
10391070

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