6.3.6. Password Expiration and Sandbox Mode

MySQL 5.7 provides a password-expiration capability, to enable database administrators to expire account passwords and require users to reset their password. This section describes how password expiration works.

To expire an account password, use the ALTER USER statement. For example:

ALTER USER 'myuser'@'localhost' PASSWORD EXPIRE;

This statement modifies the row of the mysql.user table associated with the named account, setting the password_expired column to 'Y'. This does not affect any current connections the account has open. For each subsequent connection that uses the account, the server either disconnects the client or handles the client in "sandbox mode," in which the server permits the client only those operations necessary to reset the expired password. (The action taken by the server depends on both client and server settings.)

If the server disconnects the client, it returns an ER_MUST_CHANGE_PASSWORD_LOGIN error:

shell> mysql -u myuser
        -pPassword: ******ERROR 1862 (HY000): Your password has expired. To log in you mustchange it using a client that supports expired passwords.

If the server puts the client in sandbox mode, these operations are permitted within the client session:

The client can reset the account password with SET PASSWORD. This modifies the row of the mysql.user table associated with the current account, setting the password_expired column to 'N'. After the password has been reset, the server restores normal access for the session, as well as for subsequent connections that use the account.

It is possible to "reset" a password by setting it to its current value. As a matter of good policy, it is preferable to choose a different password.
The client can use SET statements. This might be necessary prior to resetting the password; for example, if the account password uses a hashing format that requires the old_passwords system variable to be set to a value different from its default.

For any operation not permitted within the session, the server returns an ER_MUST_CHANGE_PASSWORD error:

mysql> USE test;ERROR 1820 (HY000): You must SET PASSWORD before executing this statement

As mentioned previously, whether the server disconnects an expired-password client or puts it in sandbox mode depends on a combination of client and server settings. The following discussion describes the relevant settings and how they interact.

On the client side, a given client indicates whether it can handle sandbox mode for expired passwords. For clients that use the C client library, there are two ways to do this:

Pass the MYSQL_OPT_CAN_HANDLE_EXPIRED_PASSWORDS flag to mysql_options() prior to connecting:

arg = 1;result = mysql_options(mysql,                       MYSQL_OPT_CAN_HANDLE_EXPIRED_PASSWORDS, &arg);

Pass the CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS flag to mysql_real_connect() at connection time:

mysql = mysql_real_connect(mysql,                           host, user, password, "test",                           port, unix_socket,CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS);

Other MySQL Connectors have their own conventions for indicating readiness to handle sandbox mode. See the relevant Connector documentation.

On the server side, if a client indicates that it can handle expired passwords, the server puts it in sandbox mode.

If a client does not indicate that it can handle expired passwords (or uses an older version of the client library that cannot so indicate), the server action depends on the value of the disconnect_on_expired_passwords system variable:

If disconnect_on_expired_passwords is enabled (the default), the server disconnects the client with an ER_MUST_CHANGE_PASSWORD_LOGIN error.
If disconnect_on_expired_passwords is disabled, the server puts the client in sandbox mode.

The preceding client and server settings apply only for accounts with expired passwords. If a client connects using a nonexpired password, the server handles the client normally.