Bug #27440 read_only allows create and drop database

When read_only option was enabled, a user without SUPER privilege could
perform CREATE DATABASE and DROP DATABASE operations.

This patch adds a check to make sure this isn't possible. It also attempts to 
simplify the logic used to determine if relevant tables are updated,
making it more human readable.


mysql-test/r/read_only.result:
  Updated result file
mysql-test/t/read_only.test:
  A test case is added which shows that it is not possible to drop or create a
  database in read-only mode despite having the GRANT permissions to do so,
  SUPER user excepted.
sql/sql_parse.cc:
  - Simplified complex predicate by grouping it in a read friendly way.
  - Added predicate to fail on database updates while running in read-only
    mode.

1 files changed, 31 insertions, 0 deletions

diff --git a/mysql-test/r/read_only.result b/mysql-test/r/read_only.result
index 69d25fbef6f..827a137f5b2 100644
--- a/mysql-test/r/read_only.result
+++ b/mysql-test/r/read_only.result
@@ -46,4 +46,35 @@ Warnings:
 Note	1051	Unknown table 'ttt'
 drop table t1,t2;
 drop user test@localhost;
+#
+# Bug #27440 read_only allows create and drop database
+#
+drop database if exists mysqltest_db1;
+drop database if exists mysqltest_db2;
+delete from mysql.user where User like 'mysqltest_%';
+delete from mysql.db where User like 'mysqltest_%';
+delete from mysql.tables_priv where User like 'mysqltest_%';
+delete from mysql.columns_priv where User like 'mysqltest_%';
+flush privileges;
+grant all on mysqltest_db2.* to `mysqltest_u1`@`%`;
+create database mysqltest_db1;
+grant all on mysqltest_db1.* to `mysqltest_u1`@`%`;
+flush privileges;
+show grants for current_user();
+Grants for mysqltest_u1@%
+GRANT USAGE ON *.* TO 'mysqltest_u1'@'%'
+GRANT ALL PRIVILEGES ON `mysqltest_db2`.* TO 'mysqltest_u1'@'%'
+GRANT ALL PRIVILEGES ON `mysqltest_db1`.* TO 'mysqltest_u1'@'%'
+create database mysqltest_db2;
+ERROR HY000: The MySQL server is running with the --read-only option so it cannot execute this statement
+show databases like '%mysqltest_db2%';
+Database (%mysqltest_db2%)
+drop database mysqltest_db1;
+ERROR HY000: The MySQL server is running with the --read-only option so it cannot execute this statement
+delete from mysql.user where User like 'mysqltest_%';
+delete from mysql.db where User like 'mysqltest_%';
+delete from mysql.tables_priv where User like 'mysqltest_%';
+delete from mysql.columns_priv where User like 'mysqltest_%';
+flush privileges;
+drop database mysqltest_db1;
 set global read_only=0;