advanced_password_check

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advanced_password_check

The advanced_password_check module provides password quality checking for Greenplum Database.

The Greenplum Database advanced_password_check module is based on the passwordcheck_extra module, which enhances the PostgreSQL passwordcheck module to support user-defined policies to strengthen passwordcheck's minimum password requirements.

Loading the Module

The advanced_password_check module provides no SQL-accessible functions. To use it, simply load it into the server. You can load it into an individual session by entering this command as a superuser:
# LOAD 'advanced_password_check';
More typical usage is to preload it into all sessions by including advanced_password_check in shared_preload_libraries in postgresql.conf:
shared_preload_libraries = 'other_libraries,advanced_password_check'
and then restarting the Greenplum Database server.

Using the advanced_password_check Module

advanced_password_check is a Greenplum Database module that you can enable and configure to check password strings against one or more user-defined policies. You can configure policies that:
  • Set a minimum password string length.
  • Set a maximum password string length.
  • Define a custom list of special characters.
  • Define rules for special character, upper/lower case character, and number inclusion in the password string.

The advanced_password_check module defines server configuration parameters that you set to configure password setting policies. These parameters include:

Table 1. Configuration Parameters
Parameter Name Type Default Value Description
minimum_length int 8 The minimum allowable length of a Greenplum Database password.
maxmum_length int 15 The maximum allowable length of Greenplum Database password.
special_chars string !@#$%^&*()_+{}|<>?= The set of characters that Greenplum Database considers to be special characters in a password.
restrict_upper bool true Specifies whether or not the password string must contain at least one upper case character.
restrict_lower bool true Specifies whether or not the password string must contain at least one lower case character.
restrict_numbers bool true Specifies whether or not the password string must contain at least one number.
restrict_special bool true Specifies whether or not the password string must contain at least one special character.

After you define your password policies, you run the gpconfig command for each configuration parameter that you must set. When you run the command, you must qualify the parameter with the module name. For example, to configure Greenplum Database to remove any requirements for a lower case letter in the password string, you run the following command:

gpadmin@gpmaster$ gpconfig -c advanced_password_check.restrict_lower -v false

After you set or change module configuration in this manner, you must reload the Greenplum Database configuration:

gpadmin@gpmaster$ gpstop -u

Example

Suppose that you have defined the following password policies:

  • The password must contain a minimum of 10 characters and a maximum of 18.
  • The password must contain a mixture of upper case and lower case characters.
  • The password must contain at least one of the default special characters.
  • The are no requirements that the password contain a number.

You would run the following commands to configure Greenplum Database to enforce these policies:

gpadmin@gpmaster$ gpconfig -c advanced_password_check.minimum_length -v 10
gpadmin@gpmaster$ gpconfig -c advanced_password_check.maximum_length -v 18
gpadmin@gpmaster$ gpconfig -c advanced_password_check.restrict_number -v false
gpadmin@gpmaster$ gpstop -u

After loading the new configuration, passwords that the Greenplum superuser sets must now follow the policies, and Greenplum returns an error for every policy that is not met. Note that Greenplum checks the password string against all of the policies, and concatenates together the messages for any errors that it encounters. For example (line breaks added for better viewability):

# testdb=# CREATE role r1 PASSWORD '12345678901112';
ERROR:  Incorrect password format: lower-case character missing, upper-case character
missing, special character missing (needs to be one listed in "<list-of-special-chars>")

Additional Module Documentation

Refer to the passwordcheck PostgreSQL documentation for more information about this module.