• Daniel Black's avatar
    MDEV-22974: mysql_native_password make "invalid" valid · 5b779c22
    Daniel Black authored
    Per b9f3f068, mysql_system_tables_data.sql creates
    a mysql_native_password with a salted hash of "invalid" so that `set password`
    will detect a native password can be applied:.
    
    SHOW CREATE USER; diligently uses this value in its output
    generating the SQL:
    
       MariaDB [(none)]> show create user;
    
       +---------------------------------------------------------------------------------------------------+
       | CREATE USER for dan@localhost                                                                     |
       +---------------------------------------------------------------------------------------------------+
       | CREATE USER `dan`@`localhost` IDENTIFIED VIA mysql_native_password USING 'invalid' OR unix_socket |
       +---------------------------------------------------------------------------------------------------+
    
    Attempting to execute this before this patch results in:
    
      MariaDB [(none)]>  CREATE USER `dan2`@`localhost` IDENTIFIED VIA mysql_native_password USING 'invalid' OR unix_socket;
      ERROR 1372 (HY000): Password hash should be a 41-digit hexadecimal number
    
    As such, deep the implementation of mysql_native_password we make "invalid" valid (pun intended)
    such that the above create user will succeed. We do this by storing
    "*THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE" (credit: Oracle MySQL), that is of an INCORRECT
    length for a scramble.
    
    In native_password_authenticate we check the length of this cached value
    and immediately fail if it is anything other than the scramble length.
    
    native_password_get_salt is only called in the context of set_user_salt, so all setting of native
    passwords to hashed content of 'invalid', quite literally create an invalid password.
    
    So other forms of "invalid" are valid SQL in creating invalid passwords:
    
       MariaDB [(none)]> set password = 'invalid';
       Query OK, 0 rows affected (0.001 sec)
    
       MariaDB [(none)]> alter user dan@localhost IDENTIFIED BY PASSWORD 'invalid';
       Query OK, 0 rows affected (0.000 sec)
    
    closes #1628
    
    Reviewer: serg@mariadb.com
    5b779c22
alter_user.result 14.8 KB