mariadb/mysql-test/suite/roles/current_role_view-12666.test
Vicențiu Ciorbaru f0ad93403f MDEV-12666: CURRENT_ROLE() and DATABASE() does not work in a view
The problem lies in how CURRENT_ROLE is defined. The
Item_func_current_role inherits from Item_func_sysconst, which defines
a safe_charset_converter to be a const_charset_converter.

During view creation, if there is no role previously set, the current_role()
function returns NULL.

This is captured on item instantiation and the
const_charset_converter call subsequently returns an Item_null.
In turn, the function is replaced with Item_null and the view is
then created with an Item_null instead of Item_func_current_role.

Without this patch, the first SHOW CREATE VIEW from the testcase would
have a where clause of WHERE role_name = NULL, while the second SHOW
CREATE VIEW would show a correctly created view.

The same applies for the DATABASE function, as it can change as well.

There is an additional problem with CURRENT_ROLE() when used in a
prepared statement. During prepared statement creation we used to set
the string_value of the function to the current role as well as the
null_value flag. During execution, if CURRENT_ROLE was not null, the
null_value flag was never set to not-null during fix_fields.

Item_func_current_user however can never be NULL so it did not show this
problem in a view before. At the same time, the CURRENT_USER() can not
be changed between prepared statement execution and creation so the
implementation where the value is stored during fix_fields is
sufficient.

Note also that DATABASE() function behaves differently during prepared
statements. See bug 25843 for details or commit
7e0ad09edf
2017-06-15 19:20:35 +03:00

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2.8 KiB
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#
# MDEV-12666 CURRENT_ROLE() does not work in a view
#
--source include/not_embedded.inc
CREATE USER has_role@'localhost';
GRANT ALL PRIVILEGES ON *.* TO has_role@'localhost';
CREATE ROLE test_role;
GRANT test_role TO has_role@'localhost';
CREATE USER no_role@'localhost';
GRANT ALL PRIVILEGES ON *.* TO no_role@'localhost';
CREATE TABLE view_role_test (
id int primary key,
role_name varchar(50)
);
INSERT INTO view_role_test VALUES (1, 'test_role');
--echo #
--echo # Use the same logic for stored procedures.
--echo #
PREPARE prepared_no_current_role FROM "SELECT * from view_role_test WHERE role_name = CURRENT_ROLE()";
--echo #
--echo # Creating a view with no CURRENT_ROLE() set and one with CURRENT_ROLE()
--echo # set. Both should produce the same SHOW CREATE VIEW output.
--echo #
CREATE
DEFINER = no_role@localhost
SQL SECURITY INVOKER
VIEW v_view_role_test_no_current_role
AS
SELECT * FROM view_role_test WHERE role_name = CURRENT_ROLE();
SHOW CREATE VIEW v_view_role_test_no_current_role;
--echo #
--echo # No values should be returned
--echo #
EXECUTE prepared_no_current_role;
SELECT * FROM view_role_test WHERE role_name = CURRENT_ROLE();
SELECT * FROM v_view_role_test_no_current_role;
--echo #
--echo # Now let's set the role. Create identical views as before. See if
--echo # their behaviour is different. It should not be.
--echo #
SET ROLE test_role;
SELECT CURRENT_USER();
SELECT CURRENT_ROLE();
--echo #
--echo # Create the VIEW and prepared Statement with a CURRENT_ROLE() set.
--echo #
CREATE
DEFINER = no_role@localhost
SQL SECURITY INVOKER
VIEW v_view_role_test_with_current_role
AS
SELECT * FROM view_role_test WHERE role_name = CURRENT_ROLE();
PREPARE prepared_with_current_role FROM "SELECT * from view_role_test WHERE role_name = CURRENT_ROLE()";
SHOW CREATE VIEW v_view_role_test_with_current_role;
--echo #
--echo # Values should be returned for all select statements as we do have
--echo # a CURRENT_ROLE() active;
--echo #
EXECUTE prepared_no_current_role;
EXECUTE prepared_with_current_role;
SELECT * FROM view_role_test WHERE role_name = CURRENT_ROLE();
SELECT * FROM v_view_role_test_no_current_role;
SELECT * FROM v_view_role_test_with_current_role;
SET ROLE NONE;
--echo #
--echo # No values should be returned for all select statements as we do not have
--echo # a CURRENT_ROLE() active;
--echo #
EXECUTE prepared_no_current_role;
EXECUTE prepared_with_current_role;
SELECT * FROM view_role_test WHERE role_name = CURRENT_ROLE();
SELECT * FROM v_view_role_test_no_current_role;
SELECT * FROM v_view_role_test_with_current_role;
DROP USER has_role@'localhost';
DROP USER no_role@'localhost';
DROP ROLE test_role;
DROP table view_role_test;
DROP VIEW v_view_role_test_no_current_role;
DROP VIEW v_view_role_test_with_current_role;
DROP PREPARE prepared_no_current_role;
DROP PREPARE prepared_with_current_role;