6.3.2 Password Validation Plugin Options and Variables

This section describes the options, system variables, and status variables that validate_password provides to enable its operation to be configured and monitored.

• Password Validation Plugin Options

• Password Validation Plugin System Variables

• Password Validation Plugin Status Variables

Password Validation Plugin Options

To control activation of the validate_password plugin, use this option:

• --validate-password[=value]

  Command-Line Format	--validate-password[=value]
  Type	Enumeration
  Default Value	ON
  Valid Values	ON OFF FORCE FORCE_PLUS_PERMANENT

  This option controls how the server loads the validate_password plugin at startup. The value should be one of those available for plugin-loading options, as described in Installing and Uninstalling Plugins. For example, --validate-password=FORCE_PLUS_PERMANENT tells the server to load the plugin at startup and prevents it from being removed while the server is running.

  This option is available only if the validate_password plugin has been previously registered with INSTALL PLUGIN or is loaded with --plugin-load-add. See Section 6.3.1, “Password Validation Plugin Installation”.

Password Validation Plugin System Variables

If the validate_password plugin is enabled, it exposes several system variables that enable configuration of password checking:

mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+--------+
| Variable_name                        | Value  |
+--------------------------------------+--------+
| validate_password_check_user_name    | OFF    |
| validate_password_dictionary_file    |        |
| validate_password_length             | 8      |
| validate_password_mixed_case_count   | 1      |
| validate_password_number_count       | 1      |
| validate_password_policy             | MEDIUM |
| validate_password_special_char_count | 1      |
+--------------------------------------+--------+

To change how passwords are checked, you can set these system variables at server startup or at runtime. The following list describes the meaning of each variable.

• validate_password_check_user_name

  Command-Line Format	--validate-password-check-user-name[={OFF|ON}]
  Introduced	5.7.15
  System Variable	validate_password_check_user_name
  Scope	Global
  Dynamic	Yes
  Type	Boolean
  Default Value	OFF

  Whether validate_password compares passwords to the user name part of the effective user account for the current session and rejects them if they match. This variable is unavailable unless validate_password is installed.

  By default, validate_password_check_user_name is disabled. This variable controls user name matching independent of the value of validate_password_policy.

  When validate_password_check_user_name is enabled, it has these effects:

  • Checking occurs in all contexts for which validate_password is invoked, which includes use of statements such as ALTER USER or SET PASSWORD to change the current user's password, and invocation of functions such as PASSWORD() and VALIDATE_PASSWORD_STRENGTH().

  • The user names used for comparison are taken from the values of the USER() and CURRENT_USER() functions for the current session. An implication is that a user who has sufficient privileges to set another user's password can set the password to that user's name, and cannot set that user' password to the name of the user executing the statement. For example, 'root'@'localhost' can set the password for 'jeffrey'@'localhost' to 'jeffrey', but cannot set the password to 'root.

  • Only the user name part of the USER() and CURRENT_USER() function values is used, not the host name part. If a user name is empty, no comparison occurs.

  • If a password is the same as the user name or its reverse, a match occurs and the password is rejected.

  • User-name matching is case-sensitive. The password and user name values are compared as binary strings on a byte-by-byte basis.

  • If a password matches the user name, VALIDATE_PASSWORD_STRENGTH() returns 0 regardless of how other validate_password system variables are set.

• validate_password_dictionary_file

  Command-Line Format	--validate-password-dictionary-file=file_name
  System Variable	validate_password_dictionary_file
  Scope	Global
  Dynamic	Yes
  Type	File name

  The path name of the dictionary file that validate_password uses for checking passwords. This variable is unavailable unless validate_password is installed.

  By default, this variable has an empty value and dictionary checks are not performed. For dictionary checks to occur, the variable value must be nonempty. If the file is named as a relative path, it is interpreted relative to the server data directory. File contents should be lowercase, one word per line. Contents are treated as having a character set of utf8. The maximum permitted file size is 1MB.

  For the dictionary file to be used during password checking, the password policy must be set to 2 (STRONG); see the description of the validate_password_policy system variable. Assuming that is true, each substring of the password of length 4 up to 100 is compared to the words in the dictionary file. Any match causes the password to be rejected. Comparisons are not case-sensitive.

  For VALIDATE_PASSWORD_STRENGTH(), the password is checked against all policies, including STRONG, so the strength assessment includes the dictionary check regardless of the validate_password_policy value.

  validate_password_dictionary_file can be set at runtime and assigning a value causes the named file to be read without a server restart.

• validate_password_length

  Command-Line Format	--validate-password-length=#
  System Variable	validate_password_length
  Scope	Global
  Dynamic	Yes
  Type	Integer
  Default Value	8
  Minimum Value	0

  The minimum number of characters that validate_password requires passwords to have. This variable is unavailable unless validate_password is installed.

  The validate_password_length minimum value is a function of several other related system variables. The value cannot be set less than the value of this expression:

  validate_password_number_count
  + validate_password_special_char_count
  + (2 * validate_password_mixed_case_count)

  If validate_password adjusts the value of validate_password_length due to the preceding constraint, it writes a message to the error log.

• validate_password_mixed_case_count

  Command-Line Format	--validate-password-mixed-case-count=#
  System Variable	validate_password_mixed_case_count
  Scope	Global
  Dynamic	Yes
  Type	Integer
  Default Value	1
  Minimum Value	0

  The minimum number of lowercase and uppercase characters that validate_password requires passwords to have if the password policy is MEDIUM or stronger. This variable is unavailable unless validate_password is installed.

  For a given validate_password_mixed_case_count value, the password must have that many lowercase characters, and that many uppercase characters.

• validate_password_number_count

  Command-Line Format	--validate-password-number-count=#
  System Variable	validate_password_number_count
  Scope	Global
  Dynamic	Yes
  Type	Integer
  Default Value	1
  Minimum Value	0

  The minimum number of numeric (digit) characters that validate_password requires passwords to have if the password policy is MEDIUM or stronger. This variable is unavailable unless validate_password is installed.

• validate_password_policy

  Command-Line Format	--validate-password-policy=value
  System Variable	validate_password_policy
  Scope	Global
  Dynamic	Yes
  Type	Enumeration
  Default Value	1
  Valid Values	0 1 2

  The password policy enforced by validate_password. This variable is unavailable unless validate_password is installed.

  validate_password_policy affects how validate_password uses its other policy-setting system variables, except for checking passwords against user names, which is controlled independently by validate_password_check_user_name.

  The validate_password_policy value can be specified using numeric values 0, 1, 2, or the corresponding symbolic values LOW, MEDIUM, STRONG. The following table describes the tests performed for each policy. For the length test, the required length is the value of the validate_password_length system variable. Similarly, the required values for the other tests are given by other validate_password_xxx variables.

  Policy	Tests Performed
  0 or LOW	Length
  1 or MEDIUM	Length; numeric, lowercase/uppercase, and special characters
  2 or STRONG	Length; numeric, lowercase/uppercase, and special characters; dictionary file

• validate_password_special_char_count

  Command-Line Format	--validate-password-special-char-count=#
  System Variable	validate_password_special_char_count
  Scope	Global
  Dynamic	Yes
  Type	Integer
  Default Value	1
  Minimum Value	0

  The minimum number of nonalphanumeric characters that validate_password requires passwords to have if the password policy is MEDIUM or stronger. This variable is unavailable unless validate_password is installed.

Password Validation Plugin Status Variables

If the validate_password plugin is enabled, it exposes status variables that provide operational information:

mysql> SHOW STATUS LIKE 'validate_password%';
+-----------------------------------------------+---------------------+
| Variable_name                                 | Value               |
+-----------------------------------------------+---------------------+
| validate_password.dictionary_file_last_parsed | 2019-10-03 08:33:49 |
| validate_password_dictionary_file_words_count | 1902                |
+-----------------------------------------------+---------------------+

The following list describes the meaning of each status variable.

• validate_password_dictionary_file_last_parsed

  When the dictionary file was last parsed.

• validate_password_dictionary_file_words_count

  The number of words read from the dictionary file.