Fix crash when an entry was added to the mysql.tables_priv

table with an empty hostname. (Bug #11330)

mysql-test/r/grant.result

@@ -435,3 +435,7 @@ ERROR 42000: INSERT,CREATE command denied to user 'mysqltest_1'@'localhost' for
 revoke all privileges on mysqltest.t1 from mysqltest_1@localhost;
 delete from mysql.user where user=_binary'mysqltest_1';
 drop database mysqltest;
+use mysql;
+insert into tables_priv values ('','mysqltest_1','test_table','test_grantor','',CURRENT_TIMESTAMP,'Select','Select');
+flush privileges;
+delete from tables_priv where host = '' and user = 'mysqltest_1';

mysql-test/t/grant.test

@@ -392,3 +392,11 @@ revoke all privileges on mysqltest.t1 from mysqltest_1@localhost;
 delete from mysql.user where user=_binary'mysqltest_1';
 drop database mysqltest;
 
+#
+# Bug #11330: Entry in tables_priv with host = '' causes crash
+#
+connection default;
+use mysql;
+insert into tables_priv values ('','mysqltest_1','test_table','test_grantor','',CURRENT_TIMESTAMP,'Select','Select');
+flush privileges;
+delete from tables_priv where host = '' and user = 'mysqltest_1';

sql/sql_acl.cc

@@ -1866,7 +1866,8 @@ GRANT_TABLE::GRANT_TABLE(TABLE *form, TABLE *col_privs)
   if (cols)
   {
     int key_len;
-    col_privs->field[0]->store(host.hostname,(uint) strlen(host.hostname),
+    col_privs->field[0]->store(host.hostname,
+                               host.hostname ? (uint) strlen(host.hostname) : 0,
                                &my_charset_latin1);
     col_privs->field[1]->store(db,(uint) strlen(db), &my_charset_latin1);
     col_privs->field[2]->store(user,(uint) strlen(user), &my_charset_latin1);