From 045f33745f863ba20acfc3fe335c575d9cd87884 Mon Sep 17 00:00:00 2001
From: Maximilian Bosch <maximilian@mbosch.me>
Date: Sat, 10 Sep 2022 15:18:05 +0200
Subject: [PATCH] Setup: remove custom dbuser creation behavior

Both PostgreSQL and MySQL can be authenticated against from Nextcloud by
supplying a database password. Now, during setup the following things
happen:

* When using postgres and the db user has elevated permissions, a new
  unprivileged db user is created and the settings `dbuser`/`dbpass` are
  altered in `config.php`.

* When using MySQL, the password is **always** regenerated since
  24.0.5/23.0.9[1].

I consider both cases problematic: the reason why people do configuration
management is to have it as single source of truth! So, IMHO any
application that silently alters config and thus causes deployed
nodes to diverge from the configuration is harmful for that.

I guess it was sheer luck that it worked for so long in NixOS because
nobody has apparently used password authentication with a privileged
user to operate Nextcloud (which is a good thing in fact).

[1] https://github.com/nextcloud/server/pull/33513
---
 lib/private/Setup/MySQL.php      | 53 --------------------------------
 lib/private/Setup/PostgreSQL.php | 26 ----------------
 2 files changed, 79 deletions(-)

diff --git a/lib/private/Setup/MySQL.php b/lib/private/Setup/MySQL.php
index 2c16cac3d2..9b2265091f 100644
--- a/lib/private/Setup/MySQL.php
+++ b/lib/private/Setup/MySQL.php
@@ -142,59 +142,6 @@ class MySQL extends AbstractDatabase {
 		$rootUser = $this->dbUser;
 		$rootPassword = $this->dbPassword;
 
-		//create a random password so we don't need to store the admin password in the config file
-		$saveSymbols = str_replace(['\"', '\\', '\'', '`'], '', ISecureRandom::CHAR_SYMBOLS);
-		$password = $this->random->generate(22, ISecureRandom::CHAR_ALPHANUMERIC . $saveSymbols)
-			. $this->random->generate(2, ISecureRandom::CHAR_UPPER)
-			. $this->random->generate(2, ISecureRandom::CHAR_LOWER)
-			. $this->random->generate(2, ISecureRandom::CHAR_DIGITS)
-			. $this->random->generate(2, $saveSymbols)
-		;
-		$this->dbPassword = str_shuffle($password);
-
-		try {
-			//user already specified in config
-			$oldUser = $this->config->getValue('dbuser', false);
-
-			//we don't have a dbuser specified in config
-			if ($this->dbUser !== $oldUser) {
-				//add prefix to the admin username to prevent collisions
-				$adminUser = substr('oc_' . $username, 0, 16);
-
-				$i = 1;
-				while (true) {
-					//this should be enough to check for admin rights in mysql
-					$query = 'SELECT user FROM mysql.user WHERE user=?';
-					$result = $connection->executeQuery($query, [$adminUser]);
-
-					//current dbuser has admin rights
-					$data = $result->fetchAll();
-					$result->closeCursor();
-					//new dbuser does not exist
-					if (count($data) === 0) {
-						//use the admin login data for the new database user
-						$this->dbUser = $adminUser;
-						$this->createDBUser($connection);
-
-						break;
-					} else {
-						//repeat with different username
-						$length = strlen((string)$i);
-						$adminUser = substr('oc_' . $username, 0, 16 - $length) . $i;
-						$i++;
-					}
-				}
-			}
-		} catch (\Exception $ex) {
-			$this->logger->info('Can not create a new MySQL user, will continue with the provided user.', [
-				'exception' => $ex,
-				'app' => 'mysql.setup',
-			]);
-			// Restore the original credentials
-			$this->dbUser = $rootUser;
-			$this->dbPassword = $rootPassword;
-		}
-
 		$this->config->setValues([
 			'dbuser' => $this->dbUser,
 			'dbpassword' => $this->dbPassword,
diff --git a/lib/private/Setup/PostgreSQL.php b/lib/private/Setup/PostgreSQL.php
index bc24909dc3..e49e5508e1 100644
--- a/lib/private/Setup/PostgreSQL.php
+++ b/lib/private/Setup/PostgreSQL.php
@@ -45,32 +45,6 @@ class PostgreSQL extends AbstractDatabase {
 			$connection = $this->connect([
 				'dbname' => 'postgres'
 			]);
-			//check for roles creation rights in postgresql
-			$builder = $connection->getQueryBuilder();
-			$builder->automaticTablePrefix(false);
-			$query = $builder
-				->select('rolname')
-				->from('pg_roles')
-				->where($builder->expr()->eq('rolcreaterole', new Literal('TRUE')))
-				->andWhere($builder->expr()->eq('rolname', $builder->createNamedParameter($this->dbUser)));
-
-			try {
-				$result = $query->execute();
-				$canCreateRoles = $result->rowCount() > 0;
-			} catch (DatabaseException $e) {
-				$canCreateRoles = false;
-			}
-
-			if ($canCreateRoles) {
-				//use the admin login data for the new database user
-
-				//add prefix to the postgresql user name to prevent collisions
-				$this->dbUser = 'oc_' . strtolower($username);
-				//create a new password so we don't need to store the admin config in the config file
-				$this->dbPassword = \OC::$server->getSecureRandom()->generate(30, ISecureRandom::CHAR_ALPHANUMERIC);
-
-				$this->createDBUser($connection);
-			}
 
 			$this->config->setValues([
 				'dbuser' => $this->dbUser,
-- 
2.36.2