103 lines
3.7 KiB
Markdown
103 lines
3.7 KiB
Markdown
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# PostgreSQL expiration date management functions
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## Table of Contents
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1. [TOC](#postgresql-expiration-date-management-functions)
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1. [Description](#description)
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2. [Instructions](#instructions)
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3. [Helper script](#helper_script)
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4. [RDS considerations](#rds_considerations)
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5. [Security considerations](#security_considerations)
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## Description
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This project tries to find a way to allow users the management of the `VALID UNTIL` expiration clause by themself.
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Everyghin without granting `super` permissions and having a histoc of changes on a _pseudo-audit_ table.
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You can easly combine this functions with the [passwordcheck extra](https://github.com/michaelpq/pg_plugins/tree/main/passwordcheck_extra) extension, the regex inside `dba.change_valid_until` match the _default_ requirements in the extension for special characters and you can change the variable `_min_password_length` to match your requirements (in the case you changed it, of course).
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| :warning: WARNING |
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|:---------------------------|
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| Amazon RDS has some notes at the end... |
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| :warning: WARNING |
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## Instructions
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### First deploy
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Modify `passchanger.sql` according your needings:
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* Change `_min_password_length` on `change_my_password` function
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* Change `_password_lifetime` on `change_valid_until` function
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Deploy `passchanger.sql` on the desired cluster/database.
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It will:
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* create a `dba` schema
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* create a `dba` role
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* create the `pwdhistory` table for audit purpouses
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* Grant the minimum permissions for this new role so the whole thing works
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* Create the 2 needed functions and grant permissions on them to `dba`
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### Updates
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Just execute the `CREATE OR REPLACE FUNCTION` part of the `passchanger.sql` file.
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| :warning: WARNING |
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|:---------------------------|
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| Amazon RDS has some notes at the end... |
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| :warning: WARNING |
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### Allowing users to use that functions
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Take the file `grants_to_grant.sql` and modify the username _dodger_ so it match the username that should have the permissions.
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Execute the grants on the cluster/database you have deployed `passchanger.sql`
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### Changing password & extending expiration date
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The user should just execute:
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```
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select dba.change_my_password('YOUR_NEW_GENERATED_PASSWORD_NOT_THIS_ONE') ;
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```
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## Helper script
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I've generated a helper script to make the process easier for users:
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```
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dodger@ciberterminal.net $ bash password_creator.sh
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-- CHECK: password check
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-- <Wl}TxqRPBQaV_N<rU#A
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-- /CHECK: password check
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-- ##############################################
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select dba.change_my_password('<Wl}TxqRPBQaV_N<rU#A') ;
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-- ##############################################
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```
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## RDS considerations
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As Amazon has modified Postgresql so you don't have access as a *real* superuser and the _dangerous_ function
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`change_valid_until` should run as the owner of the database (the user created when you deploy the database through AWS)
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There's a `passchanger_rds.sql` file which should be used instead of the normal one.
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For updates you should change the owner of the `change_valid_until` to the database _owner_:
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```
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ALTER FUNCTION dba.change_valid_until(text) OWNER TO _DATABASEOWNER;
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```
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Modify `_DATABASEOWNER` according your admin username...
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## Security considerations
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* Non-RDS `change_valid_until` function does not uses `ALTER USER` to modify `VALID UNTIL`, it makes an `update pg_catalog.pg_authid set rolvaliduntil` instead, so the `dba` user has only grant over that table/column instead of granting additional permissions to him.
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* RDS `change_valid_until` should run as the database owner, is the only way to make this work as you can't access `pg_catalog.pg_authid` on rds, it uses `ALTER USER ... VALID UNTIL` instead.
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