Note: This wiki page explains how you can configure X2Go with PostgreSQL as database backend. However, for small setups, this is unneccessary. If you have one standalone X2Go server and only a small number of users, then you can use the SQLite database backend (which is the default after installation of the
x2goserver package). The PostgreSQL backend is recommended for sites that run more than one X2Go Server (X2Go multi-node farms) and/or a large number of users.
With X2Go Server v22.214.171.124 the whole session database backend code had been fully rewritten due to a serious security issue that had been brought up by Morty, Reinhard and Arw. Sind then, the
sudo command is no longer required by
x2goserver to neither contact the
SQLite database (installation default) nor the PostgreSQL database. Since v3.0.99.x PostgreSQL views and rules are used to restrict users from modifying or accessing data of other users.
For accessing the X2Go/PostgreSQL database X2Go Server uses the Perl DBI package.
# IPv4 local connections: host all all 127.0.0.1/32 md5
You must create a database user which can create databases and users for
X2Go database administration. You can also use the
postgres user to do this
You must save the password of this user in the file
Only root should have access to this file. It will be used only for database and user creation, you may/should delete it after these tasks are done. You can set a new password using this command on your PostgreSQL server:
$ su postgres -c "psql" psql (8.4.8) You are using psql, the command-line interface to PostgreSQL. Type: \copyright for distribution terms \h for help with SQL commands \? for help with psql commands \g or terminate with semicolon to execute query \q to quit postgres=# alter user postgres encrypted password '<secret-password>'; ALTER ROLE postgres=# \q
#postgres or sqlite backend=postgres [postgres] host=localhost port=5432 #database admin (must have permissions to create databases and users) dbadmin=postgres #disable: SSL connections are never used #allow: try non-SSL, then SSL #prefer: try SSL, then non-SSL #require: connect only with SSL #default - prefer ssl=prefer
$ /usr/lib/x2go/script/x2godbadmin --help X2Go SQL admin interface. Use it to create the X2Go session database and insert or remove users or groups in X2Go session database. Usage: x2godbadmin --createdb x2godbadmin --listusers x2godbadmin --adduser|rmuser <UNIX user> x2godbadmin --addgroup|rmgroup <UNIX group>
$ x2godbadmin --createdb
You can add UNIX users or groups to database using commands $ x2godbadmin --adduser example <code> $ x2godbadmin --addgroup x2gousers
After that step users of the posix group
x2gousers can create X2Go sessions. Of course, any other group could be used here, as well.
In hopefully rare cases it may become necessary to fix the X2Go session database via standard PostgreSQL tools (e.g.
psql). This should not happen and please please please report the issue as a bug against the x2goserver X2Go component. However, if you are in the unlucky situation of having to fix up the session DB, then the below lines may render useful to you.
In case it becomes necessary to edit the X2Go session database on the PostgreSQL server by hand, connect to the DB with this command:
$ psql --user x2godbuser --password -h localhost --dbname x2go_sessions
As password use the password found in
After successful login, the
psql PostgreSQL client shows these lines:
ts-01:~ # psql --user x2godbuser --password -h localhost --dbname x2go_sessions Password for user x2godbuser: <hidden> Welcome to psql <version>, the PostgreSQL interactive terminal. Type: \copyright for distribution terms \h for help with SQL commands \? for help with psql commands \g or terminate with semicolon to execute query \q to quit x2go_sessions=>
The database has five tables:
x2go_sessions=> \dt List of relations Schema | Name | Type | Owner --------+---------------+-------+---------- public | messages | table | postgres public | mounts | table | postgres public | sessions | table | postgres public | used_ports | table | postgres public | user_messages | table | postgres (5 rows)
Three of them are important for session management: sessions, used_ports, mounts.
Furthermore, the database defined four views:
x2go_sessions=> \dv List of relations Schema | Name | Type | Owner --------+---------------+------+---------- public | mounts_view | view | postgres public | ports_view | view | postgres public | servers_view | view | postgres public | sessions_view | view | postgres (4 rows) x2go_sessions=>
If you want to show the content of a table or view, evoke this SQL command:
x2go_sessions=> select * from used_ports; server | session_id | creator_id | port --------------+---------------------------------------+-----------------+------- ts-01 | mike-57-1379961697_stRTERMINAL_dp24 | x2gouser_mike | 30019 ts-01 | mike-57-1379961697_stRTERMINAL_dp24 | x2gouser_mike | 30018 ts-01 | mike-57-1379961697_stRTERMINAL_dp24 | x2gouser_mike | 30020 (3 rows)
If you want to remove these entries (because they are there but they by some reason should not be there), use this command set:
x2go_sessions=> delete from used_ports where port=30020; DELETE 1
… or …
x2go_sessions=> delete from used_ports where session_id=mike-57-1379961697_stRTERMINAL_dp24; DELETE 3
For further input on manipulating PostgreSQL database via the
psql client tool, see the PostgreSQL reference.