Add a regression test for allow_system_table_mods

Add a regression test file that exercises the kinds of commands that
allow_system_table_mods allows.

This is put in the "unsafe_tests" suite, so it won't accidentally
create a mess if someone runs the normal regression tests against an
instance that they care about.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/8b00ea5e-28a7-88ba-e848-21528b632354%402ndquadrant.com

src/test/modules/unsafe_tests/Makefile

@@ -1,6 +1,6 @@
 # src/test/modules/unsafe_tests/Makefile
 
-REGRESS = rolenames
+REGRESS = rolenames alter_system_table
 
 ifdef USE_PGXS
 PG_CONFIG = pg_config

src/test/modules/unsafe_tests/expected/alter_system_table.out

@@ -0,0 +1,168 @@
+--
+-- Tests for things affected by allow_system_table_mods
+--
+-- We run the same set of commands once with allow_system_table_mods
+-- off and then again with on.
+--
+-- The "on" tests should where possible be wrapped in BEGIN/ROLLBACK
+-- blocks so as to not leave a mess around.
+CREATE USER regress_user_ast;
+SET allow_system_table_mods = off;
+-- create new table in pg_catalog
+CREATE TABLE pg_catalog.test (a int);
+ERROR:  permission denied to create "pg_catalog.test"
+DETAIL:  System catalog modifications are currently disallowed.
+-- anyarray column
+CREATE TABLE t1x (a int, b anyarray);
+ERROR:  column "b" has pseudo-type anyarray
+-- index on system catalog
+ALTER TABLE pg_namespace ADD UNIQUE USING INDEX pg_namespace_oid_index;
+ERROR:  permission denied: "pg_namespace" is a system catalog
+-- write to system catalog table as superuser
+-- (allowed even without allow_system_table_mods)
+INSERT INTO pg_description (objoid, classoid, objsubid, description) VALUES (0, 0, 0, 'foo');
+-- write to system catalog table as normal user
+GRANT INSERT ON pg_description TO regress_user_ast;
+SET ROLE regress_user_ast;
+INSERT INTO pg_description (objoid, classoid, objsubid, description) VALUES (0, 0, 1, 'foo');
+ERROR:  permission denied for table pg_description
+RESET ROLE;
+-- policy on system catalog
+CREATE POLICY foo ON pg_description FOR SELECT USING (description NOT LIKE 'secret%');
+ERROR:  permission denied: "pg_description" is a system catalog
+-- reserved schema name
+CREATE SCHEMA pg_foo;
+ERROR:  unacceptable schema name "pg_foo"
+DETAIL:  The prefix "pg_" is reserved for system schemas.
+-- drop system table
+DROP TABLE pg_description;
+ERROR:  permission denied: "pg_description" is a system catalog
+-- truncate of system table
+TRUNCATE pg_description;
+ERROR:  permission denied: "pg_description" is a system catalog
+-- rename column of system table
+ALTER TABLE pg_description RENAME COLUMN description TO comment;
+ERROR:  permission denied: "pg_description" is a system catalog
+-- ATSimplePermissions()
+ALTER TABLE pg_description ALTER COLUMN description SET NOT NULL;
+ERROR:  permission denied: "pg_description" is a system catalog
+-- SET STATISTICS
+ALTER TABLE pg_description ALTER COLUMN description SET STATISTICS -1;
+ERROR:  permission denied: "pg_description" is a system catalog
+-- foreign key referencing catalog
+CREATE TABLE foo (a oid, b oid, c int, FOREIGN KEY (a, b, c) REFERENCES pg_description);
+ERROR:  permission denied: "pg_description" is a system catalog
+-- RangeVarCallbackOwnsRelation()
+CREATE INDEX pg_descripton_test_index ON pg_description (description);
+ERROR:  permission denied: "pg_description" is a system catalog
+-- RangeVarCallbackForAlterRelation()
+ALTER TABLE pg_description RENAME TO pg_comment;
+ERROR:  permission denied: "pg_description" is a system catalog
+ALTER TABLE pg_description SET SCHEMA public;
+ERROR:  permission denied: "pg_description" is a system catalog
+-- reserved tablespace name
+CREATE TABLESPACE pg_foo LOCATION '/no/such/location';
+ERROR:  unacceptable tablespace name "pg_foo"
+DETAIL:  The prefix "pg_" is reserved for system tablespaces.
+-- triggers
+CREATE FUNCTION tf1() RETURNS trigger
+LANGUAGE plpgsql
+AS $$
+BEGIN
+  RETURN NULL;
+END $$;
+CREATE TRIGGER t1 BEFORE INSERT ON pg_description EXECUTE FUNCTION tf1();
+ERROR:  permission denied: "pg_description" is a system catalog
+ALTER TRIGGER t1 ON pg_description RENAME TO t2;
+ERROR:  permission denied: "pg_description" is a system catalog
+--DROP TRIGGER t2 ON pg_description;
+-- rules
+CREATE RULE r1 AS ON INSERT TO pg_description DO INSTEAD NOTHING;
+ERROR:  permission denied: "pg_description" is a system catalog
+ALTER RULE r1 ON pg_description RENAME TO r2;
+ERROR:  permission denied: "pg_description" is a system catalog
+--DROP RULE r2 ON pg_description;
+SET allow_system_table_mods = on;
+-- create new table in pg_catalog
+BEGIN;
+CREATE TABLE pg_catalog.test (a int);
+ROLLBACK;
+-- anyarray column
+BEGIN;
+CREATE TABLE t1 (a int, b anyarray);
+ROLLBACK;
+-- index on system catalog
+BEGIN;
+ALTER TABLE pg_namespace ADD UNIQUE USING INDEX pg_namespace_oid_index;
+ROLLBACK;
+-- write to system catalog table as superuser
+BEGIN;
+INSERT INTO pg_description (objoid, classoid, objsubid, description) VALUES (0, 0, 2, 'foo');
+ROLLBACK;
+-- write to system catalog table as normal user
+-- (not allowed)
+SET ROLE regress_user_ast;
+INSERT INTO pg_description (objoid, classoid, objsubid, description) VALUES (0, 0, 3, 'foo');
+ERROR:  permission denied for table pg_description
+RESET ROLE;
+-- policy on system catalog
+BEGIN;
+CREATE POLICY foo ON pg_description FOR SELECT USING (description NOT LIKE 'secret%');
+ROLLBACK;
+-- reserved schema name
+BEGIN;
+CREATE SCHEMA pg_foo;
+ROLLBACK;
+-- drop system table
+-- (This will fail anyway because it's pinned.)
+BEGIN;
+DROP TABLE pg_description;
+ERROR:  cannot drop table pg_description because it is required by the database system
+ROLLBACK;
+-- truncate of system table
+BEGIN;
+TRUNCATE pg_description;
+ROLLBACK;
+-- rename column of system table
+BEGIN;
+ALTER TABLE pg_description RENAME COLUMN description TO comment;
+ROLLBACK;
+-- ATSimplePermissions()
+BEGIN;
+ALTER TABLE pg_description ALTER COLUMN description SET NOT NULL;
+ROLLBACK;
+-- SET STATISTICS
+BEGIN;
+ALTER TABLE pg_description ALTER COLUMN description SET STATISTICS -1;
+ROLLBACK;
+-- foreign key referencing catalog
+BEGIN;
+ALTER TABLE pg_description ADD PRIMARY KEY USING INDEX pg_description_o_c_o_index;
+CREATE TABLE foo (a oid, b oid, c int, FOREIGN KEY (a, b, c) REFERENCES pg_description);
+ROLLBACK;
+-- RangeVarCallbackOwnsRelation()
+BEGIN;
+CREATE INDEX pg_descripton_test_index ON pg_description (description);
+ROLLBACK;
+-- RangeVarCallbackForAlterRelation()
+BEGIN;
+ALTER TABLE pg_description RENAME TO pg_comment;
+ROLLBACK;
+BEGIN;
+ALTER TABLE pg_description SET SCHEMA public;
+ROLLBACK;
+-- reserved tablespace name
+CREATE TABLESPACE pg_foo LOCATION '/no/such/location';
+ERROR:  directory "/no/such/location" does not exist
+-- triggers
+CREATE TRIGGER t1 BEFORE INSERT ON pg_description EXECUTE FUNCTION tf1();
+ALTER TRIGGER t1 ON pg_description RENAME TO t2;
+DROP TRIGGER t2 ON pg_description;
+-- rules
+CREATE RULE r1 AS ON INSERT TO pg_description DO INSTEAD NOTHING;
+ALTER RULE r1 ON pg_description RENAME TO r2;
+DROP RULE r2 ON pg_description;
+-- cleanup
+REVOKE ALL ON pg_description FROM regress_user_ast;
+DROP USER regress_user_ast;
+DROP FUNCTION tf1;

src/test/modules/unsafe_tests/sql/alter_system_table.sql

@@ -0,0 +1,185 @@
+--
+-- Tests for things affected by allow_system_table_mods
+--
+-- We run the same set of commands once with allow_system_table_mods
+-- off and then again with on.
+--
+-- The "on" tests should where possible be wrapped in BEGIN/ROLLBACK
+-- blocks so as to not leave a mess around.
+
+CREATE USER regress_user_ast;
+
+SET allow_system_table_mods = off;
+
+-- create new table in pg_catalog
+CREATE TABLE pg_catalog.test (a int);
+
+-- anyarray column
+CREATE TABLE t1x (a int, b anyarray);
+
+-- index on system catalog
+ALTER TABLE pg_namespace ADD UNIQUE USING INDEX pg_namespace_oid_index;
+
+-- write to system catalog table as superuser
+-- (allowed even without allow_system_table_mods)
+INSERT INTO pg_description (objoid, classoid, objsubid, description) VALUES (0, 0, 0, 'foo');
+
+-- write to system catalog table as normal user
+GRANT INSERT ON pg_description TO regress_user_ast;
+SET ROLE regress_user_ast;
+INSERT INTO pg_description (objoid, classoid, objsubid, description) VALUES (0, 0, 1, 'foo');
+RESET ROLE;
+
+-- policy on system catalog
+CREATE POLICY foo ON pg_description FOR SELECT USING (description NOT LIKE 'secret%');
+
+-- reserved schema name
+CREATE SCHEMA pg_foo;
+
+-- drop system table
+DROP TABLE pg_description;
+
+-- truncate of system table
+TRUNCATE pg_description;
+
+-- rename column of system table
+ALTER TABLE pg_description RENAME COLUMN description TO comment;
+
+-- ATSimplePermissions()
+ALTER TABLE pg_description ALTER COLUMN description SET NOT NULL;
+
+-- SET STATISTICS
+ALTER TABLE pg_description ALTER COLUMN description SET STATISTICS -1;
+
+-- foreign key referencing catalog
+CREATE TABLE foo (a oid, b oid, c int, FOREIGN KEY (a, b, c) REFERENCES pg_description);
+
+-- RangeVarCallbackOwnsRelation()
+CREATE INDEX pg_descripton_test_index ON pg_description (description);
+
+-- RangeVarCallbackForAlterRelation()
+ALTER TABLE pg_description RENAME TO pg_comment;
+ALTER TABLE pg_description SET SCHEMA public;
+
+-- reserved tablespace name
+CREATE TABLESPACE pg_foo LOCATION '/no/such/location';
+
+-- triggers
+CREATE FUNCTION tf1() RETURNS trigger
+LANGUAGE plpgsql
+AS $$
+BEGIN
+  RETURN NULL;
+END $$;
+
+CREATE TRIGGER t1 BEFORE INSERT ON pg_description EXECUTE FUNCTION tf1();
+ALTER TRIGGER t1 ON pg_description RENAME TO t2;
+--DROP TRIGGER t2 ON pg_description;
+
+-- rules
+CREATE RULE r1 AS ON INSERT TO pg_description DO INSTEAD NOTHING;
+ALTER RULE r1 ON pg_description RENAME TO r2;
+--DROP RULE r2 ON pg_description;
+
+
+SET allow_system_table_mods = on;
+
+-- create new table in pg_catalog
+BEGIN;
+CREATE TABLE pg_catalog.test (a int);
+ROLLBACK;
+
+-- anyarray column
+BEGIN;
+CREATE TABLE t1 (a int, b anyarray);
+ROLLBACK;
+
+-- index on system catalog
+BEGIN;
+ALTER TABLE pg_namespace ADD UNIQUE USING INDEX pg_namespace_oid_index;
+ROLLBACK;
+
+-- write to system catalog table as superuser
+BEGIN;
+INSERT INTO pg_description (objoid, classoid, objsubid, description) VALUES (0, 0, 2, 'foo');
+ROLLBACK;
+
+-- write to system catalog table as normal user
+-- (not allowed)
+SET ROLE regress_user_ast;
+INSERT INTO pg_description (objoid, classoid, objsubid, description) VALUES (0, 0, 3, 'foo');
+RESET ROLE;
+
+-- policy on system catalog
+BEGIN;
+CREATE POLICY foo ON pg_description FOR SELECT USING (description NOT LIKE 'secret%');
+ROLLBACK;
+
+-- reserved schema name
+BEGIN;
+CREATE SCHEMA pg_foo;
+ROLLBACK;
+
+-- drop system table
+-- (This will fail anyway because it's pinned.)
+BEGIN;
+DROP TABLE pg_description;
+ROLLBACK;
+
+-- truncate of system table
+BEGIN;
+TRUNCATE pg_description;
+ROLLBACK;
+
+-- rename column of system table
+BEGIN;
+ALTER TABLE pg_description RENAME COLUMN description TO comment;
+ROLLBACK;
+
+-- ATSimplePermissions()
+BEGIN;
+ALTER TABLE pg_description ALTER COLUMN description SET NOT NULL;
+ROLLBACK;
+
+-- SET STATISTICS
+BEGIN;
+ALTER TABLE pg_description ALTER COLUMN description SET STATISTICS -1;
+ROLLBACK;
+
+-- foreign key referencing catalog
+BEGIN;
+ALTER TABLE pg_description ADD PRIMARY KEY USING INDEX pg_description_o_c_o_index;
+CREATE TABLE foo (a oid, b oid, c int, FOREIGN KEY (a, b, c) REFERENCES pg_description);
+ROLLBACK;
+
+-- RangeVarCallbackOwnsRelation()
+BEGIN;
+CREATE INDEX pg_descripton_test_index ON pg_description (description);
+ROLLBACK;
+
+-- RangeVarCallbackForAlterRelation()
+BEGIN;
+ALTER TABLE pg_description RENAME TO pg_comment;
+ROLLBACK;
+BEGIN;
+ALTER TABLE pg_description SET SCHEMA public;
+ROLLBACK;
+
+-- reserved tablespace name
+CREATE TABLESPACE pg_foo LOCATION '/no/such/location';
+
+-- triggers
+CREATE TRIGGER t1 BEFORE INSERT ON pg_description EXECUTE FUNCTION tf1();
+ALTER TRIGGER t1 ON pg_description RENAME TO t2;
+DROP TRIGGER t2 ON pg_description;
+
+-- rules
+CREATE RULE r1 AS ON INSERT TO pg_description DO INSTEAD NOTHING;
+ALTER RULE r1 ON pg_description RENAME TO r2;
+DROP RULE r2 ON pg_description;
+
+
+-- cleanup
+REVOKE ALL ON pg_description FROM regress_user_ast;
+DROP USER regress_user_ast;
+DROP FUNCTION tf1;

src/test/regress/expected/alter_table.out

@@ -3309,10 +3309,6 @@ WHERE c.oid IS NOT NULL OR m.mapped_oid IS NOT NULL;
 
 -- Checks on creating and manipulation of user defined relations in
 -- pg_catalog.
---
--- XXX: It would be useful to add checks around trying to manipulate
--- catalog tables, but that might have ugly consequences when run
--- against an existing server with allow_system_table_mods = on.
 SHOW allow_system_table_mods;
  allow_system_table_mods 
 -------------------------

src/test/regress/sql/alter_table.sql

@@ -2079,10 +2079,6 @@ WHERE c.oid IS NOT NULL OR m.mapped_oid IS NOT NULL;
 
 -- Checks on creating and manipulation of user defined relations in
 -- pg_catalog.
---
--- XXX: It would be useful to add checks around trying to manipulate
--- catalog tables, but that might have ugly consequences when run
--- against an existing server with allow_system_table_mods = on.
 
 SHOW allow_system_table_mods;
 -- disallowed because of search_path issues with pg_dump