Information schema leaks table names and structure to unauthorized users

--source include/have_innodb.inc

create database db;

create table db.t1 (x int, key(x)) engine=InnoDB;

create table db.t2 (a int, b int, c int, unique(b), check(c>b), foreign key(c) references db.t1(x)) engine=InnoDB;

create user u@localhost;

grant select (a) on db.t2 to u@localhost;

--connect (con1,localhost,u,,db)

--echo #

--echo # This is OK:

select table_name, column_name from information_schema.columns where table_name in ('t1','t2');

--echo #

--echo # This is not:

select table_name, column_name from information_schema.key_column_usage where table_name in ('t1','t2');

select table_name, unique_constraint_name, referenced_table_name from information_schema.referential_constraints where table_name in ('t1','t2');

--echo #

--echo # This is possibly not OK either:

select table_name, constraint_name from information_schema.table_constraints where table_name in ('t1','t2');

select table_name, constraint_name, constraint_type from information_schema.table_constraints where table_name in ('t1','t2');

show index in t2;

# Cleanup

--disconnect con1

--connection default

drop user u@localhost;

drop database db;

# This is OK:

select table_name, column_name from information_schema.columns where table_name in ('t1','t2');

table_name	column_name

t2	a

#

# This is not:

select table_name, column_name from information_schema.key_column_usage where table_name in ('t1','t2');

table_name	column_name

t2	b

t2	c

select table_name, unique_constraint_name, referenced_table_name from information_schema.referential_constraints where table_name in ('t1','t2');

table_name	unique_constraint_name	referenced_table_name

t2	x	t1

#

# This is possibly not OK either:

select table_name, constraint_name from information_schema.table_constraints where table_name in ('t1','t2');

table_name	constraint_name

t2	b

t2	CONSTRAINT_1

t2	t2_ibfk_1

select table_name, constraint_name, constraint_type from information_schema.table_constraints where table_name in ('t1','t2');

table_name	constraint_name	constraint_type

t2	b	UNIQUE

t2	CONSTRAINT_1	CHECK

t2	t2_ibfk_1	FOREIGN KEY

show index in t2;

Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment

t2	0	b	1	b	A	0	NULL	NULL	YES	BTREE		

t2	1	c	1	c	A	0	NULL	NULL	YES	BTREE