Table of Contents
Guacamole supports authentication via MySQL or PostgreSQL databases through extensions available from the project website. These extensions allows users and connections to be managed from within the web application. Unlike the default, XML-driven authentication module, all changes to users and connections take effect immediately; users need not logout and back in in order to see new connections.
The official database authentication also supports load balancing through the use of "balancing groups". When a balancing group is created, it can be used like any other connection, but will use the least-used of its underlying connections, spreading load evenly across any connections contained within.
The database authentication modules are not included in the main Guacamole bundle nor are they enabled by default. You must use the download link provided in the downloads section of the main Guacamole site.
The downloaded .tar.gz
file will contain several
directories:
mysql/
Contains the MySQL authentication module as a
.jar
file, along with aschema/
directory containing the SQL scripts required to set up the database.The MySQL JDBC connector is not included. You must obtain the JDBC connector
.jar
from within the "Connector/J" archive downloadable from MySQL's website.postgresql/
Contains the PostgreSQL authentication module as a
.jar
file, along with aschema/
directory containing the SQL scripts required to set up the database.The PostgreSQL JDBC driver is not included. You must obtain the JDBC driver
.jar
from PostgreSQL's website. The proper.jar
file depends on the version of Java you have installed.
The authentication module .jar
file for your database must be
copied into the directory specified by the lib-directory property
in guacamole.properties
, along with the your database's JDBC
driver. If this property is not specified, you will need to add it. On Linux servers,
/var/lib/guacamole/classpath
is a good choice, but it can be
whatever you like.
After copying the files in place, check to make sure everything looks sane.
The contents of for a MySQL database should match the files shown here:
$
ls/var/lib/guacamole/classpath
guacamole-auth-jdbc-mysql-0.9.6.jar mysql-connector-java-5.1.23-bin.jar
$
For PostgreSQL, the contents should match the files shown here:
$
ls/var/lib/guacamole/classpath
guacamole-auth-jdbc-postgresql-0.9.6.jar postgresql-9.4-1201.jdbc41.jar
$
Each of the .jar
files above is either the authentication module
itself (guacamole-auth-jdbc-*-0.9.6.jar
) or the corresponding JDBC
driver. If any of these files is missing, authentication will not
work!
The database authentication module will need a database to store all authentication data and a user to use only for data access and manipulation. You could use an existing database and existing user, but for the sake of simplicity and security, these instructions assume you will be creating a new database and new user that will be used only by Guacamole and only for this authentication module.
At this point, you need either MySQL or PostgreSQL installed, and must have sufficient access to create and administer databases. If this is not the case, install your database of choice now. Most distributions will provide a convenient MySQL or PostgreSQL package which will set up everything for you, including the root database user, if applicable.
For the sake of clarity, these instructions will refer to the database as "guacamole_db" and the user as "guacamole_user", but the database and user can be named whatever you like. Naturally, you should also choose a real password for your user rather than the string "some_password" used as a placeholder below.
If using MySQL, you must create your database and user first:
$
mysql -u root -pEnter password:
password
Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 233 Server version: 5.5.29-0ubuntu0.12.10.1 (Ubuntu) Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
CREATE DATABASE
guacamole_db
;Query OK, 1 row affected (0.00 sec)
mysql>
CREATE USER '
guacamole_user'
@'localhost' IDENTIFIED BY 'some_password
';Query OK, 0 rows affected (0.00 sec)
mysql>
GRANT SELECT,INSERT,UPDATE,DELETE ON
guacamole_db
.* TO 'guacamole_user'
@'localhost';Query OK, 0 rows affected (0.00 sec)
mysql>
FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.02 sec)
mysql>
quit
Bye
$
Once the database and user are created, the database schema must be applied by
running the supplied SQL scripts. These SQL scripts are included in the
mysql/schema/
directory of the archive you downloaded from
the Guacamole website. They are named such that they can be run in order with one
command:
$
ls schema/
001-create-schema.sql 002-create-admin-user.sql upgrade
$
cat schema/*.sql | mysql -u root -p
guacamole_db
Enter password:
password
$
If the operation is successful, all tables have been created successfully, and the database is now ready for use.
Important
If you are upgrading from an older version of Guacamole that lacked support
for connection groups (older than 0.8.2), you should instead run the upgrade
script located within the upgrade/
directory:
$
ls schema/upgrade/
upgrade-pre-0.8.2.sql upgrade-pre-0.9.6.sql
$
mysql -u root -p
guacamole_db
< schema/upgrade/upgrade-pre-0.8.2.sqlEnter password:
password
$
If you are upgrading from a version of Guacamole before 0.9.6, the default permissions associated with new users have changed such that users can change their own passwords. You may, if desired, run the upgrade script to migrate any existing users to the new permissions:
$
mysql -u root -p
guacamole_db
< schema/upgrade/upgrade-pre-0.9.6.sqlEnter password:
password
$
If using PostgreSQL, the database and schema must be created first:
$
createdb
guacamole_db
$
ls schema/
001-create-schema.sql 002-create-admin-user.sql
$
cat schema/*.sql | psql -d
guacamole_db
-f -CREATE TYPE CREATE TYPE CREATE TYPE CREATE TABLE CREATE INDEX
...INSERT 0 1 INSERT 0 4 INSERT 0 3
$
Once the database exists, you can safely create a new user for the database, and grant that user sufficient privileges to manage the contents of all tables in the database:
$
psql -d
guacamole_db
psql (9.3.6) Type "help" for help.
guacamole=#
CREATE USER
guacamole_user
WITH PASSWORD 'some_password
';CREATE ROLE
guacamole=#
GRANT SELECT,INSERT,UPDATE,DELETE ON ALL TABLES IN SCHEMA public TO
guacamole_user
;GRANT
guacamole=#
GRANT SELECT,USAGE ON ALL SEQUENCES IN SCHEMA public TO
guacamole_user
;GRANT
guacamole=#
\q
$
As support for PostgreSQL was not added until 0.9.6, no upgrade scripts are necessary to migrate the databases of earlier versions of Guacamole; no such databases exist.
Now that the database has been created, and all required SQL scripts have been run, we
need to add a few properties to guacamole.properties
such that
Guacamole will load the appropriate authentication module and connect to the proper
database. These properties are specific to the database being used.
To use a MySQL database, you will need to specify the following:
# Auth provider class auth-provider: net.sourceforge.guacamole.net.auth.mysql.MySQLAuthenticationProvider # MySQL properties mysql-hostname: localhost mysql-port: 3306 mysql-database:guacamole_db
mysql-username:guacamole_user
mysql-password:some_password
For PostgreSQL the properties are similar, but with different prefixes:
# Auth provider class auth-provider: org.glyptodon.guacamole.auth.postgresql.PostgreSQLAuthenticationProvider # MySQL properties postgresql-hostname: localhost postgresql-port: 5432 postgresql-database:guacamole_db
postgresql-username:guacamole_user
postgresql-password:some_password
Be sure to specify the correct password for the MySQL or PostgreSQL user you created, and specify the correct database and username if you didn't use "guacamole_db" and "guacamole_user".
The database authentication module also provides configuration options to restrict concurrent use of connections if desired:
# MySQL mysql-disallow-simultaneous-connections: true # PostgreSQL postgresql-disallow-simultaneous-connections: true
This is not required, but with the above property in place, users attempting to use a connection that is already in use by another user will be denied access. By default, concurrent access is allowed. This does not affect balancing groups, but does affect the usage of connections within balancing groups.
Concurrent access to balancing groups is restricted by default, and while balancing groups can be used by any number of users simultaneously, each individual user may only have one active connection to a balancing group. You can change this if you wish, but beware that individual users will then be able to exhaust the available connections of a balancing group:
# MySQL mysql-disallow-duplicate-connections: false # PostgreSQL postgresql-disallow-duplicate-connections: false
Once you have guacamole.properties
modified appropriately,
restart Tomcat (or whatever servlet container you are using) and Guacamole will use your
database for authentication. Be sure to watch the logs in case something is wrong with
the configuration, and remember that, for security reasons, Guacamole will always report
authentication errors as "invalid login" regardless of the true cause.
The default Guacamole user created by the provided SQL scripts is "guacadmin", with a default password of "guacadmin". Once you have the database authentication working, you should change your password immediately by editing your own user in the administration screen.
More detailed instructions for managing users and connections is given in Chapter 8, Administration.
If necessary, it is possible to modify the data backing the authentication module manually by executing SQL statements against the database. In general use, this will not be common, but if you need to bulk-insert a large number of users or connections, or you wish to translate an existing configuration automatically, you will need to know how everything is laid out at a high level.
This section assumes knowledge of SQL and your chosen database, and that whatever you need to do can be accomplished if only you had high-level information about Guacamole's SQL schema.
Every user has a corresponding entry in the guacamole_user
table. Each user has a corresponding unique username and salted password. The salted
password is split into two columns: one containing the salt, and the other
containing the password hashed with SHA-256.
The guacamole_user
table contains the following
columns:
- user_id
The unique integer associated with each user. This value is generated automatically when a new entry is inserted into the
guacamole_user
table.- username
The unique name associated with each user. This value must be specified manually, and must be different from any existing username in the table. References to users in other tables use the value from user_id, not username.
- password_hash
The result of hashing the user's password concatenated with the contents of password_salt using SHA-256. The salt is appended to the password prior to hashing.
Although passwords set through Guacamole will always be salted, it is possible to use unsalted password hashes when inserted manually or through an external system. If password_salt is
NULL
, the password_hash will be handled as a simple unsalted hash of the password.- password_salt
A 32-byte random value. When a new user is created from the web interface, this value is randomly generated using a cryptographically-secure random number generator.
This will always be set for users whose passwords are set through Guacamole, but it is possible to use unsalted password hashes when inserted manually or through an external system. If password_salt is
NULL
, the password_hash will be handled as a simple unsalted hash of the password.
Important
If you choose to manually set unsalted password hashes, please be sure you understand the security implications of doing so.
In the event that your database is compromised, finding the password for a salted hash is computationally infeasible, but finding the password for an unsalted hash is often not. In many cases, the password which corresponds to an unsalted hash can be found simply by entering the hash into a search engine like Google.
If creating a user manually, the main complication is the salt, which must be determined before the INSERT statement can be constructed, but this can be dealt with using variables. For MySQL:
-- Generate salt SET @salt = UNHEX(SHA2(UUID(), 256)); -- Create user and hash password with salt INSERT INTO guacamole_user (username, password_salt, password_hash) VALUES ('myuser', @salt, UNHEX(SHA2(CONCAT('mypassword', HEX(@salt)), 256)));
This sort of statement is useful for both creating new users or for changing passwords, especially if all administrators have forgotten theirs.
If you are not using MySQL, or you are using a version of MySQL that lacks the
SHA2
function, you will need to calculate the SHA-256
value manually (by using the sha256sum command, for
example).
Each connection has an entry in the guacamole_connection
table, with a one-to-many relationship to parameters, stored as name/value pairs in
the guacamole_connection_parameter
table.
The guacamole_connection
table is simply a pairing of a
unique and descriptive name with the protocol to be used for the connection. It
contains the following columns:
- connection_id
The unique integer associated with each connection. This value is generated automatically when a new entry is inserted into the
guacamole_connection
table.- connection_name
The unique name associated with each connection. This value must be specified manually, and must be different from any existing connection name in the same connection group. References to connections in other tables use the value from connection_id, not connection_name.
- protocol
The protocol to use with this connection. This is the name of the protocol that should be sent to guacd when connecting, for example "vnc" or "rdp".
- parent_id
The unique integer associated with the connection group containing this connection, or
NULL
if this connection is within the root group.
As there are potentially multiple parameters per connection, where the names of
each parameter are completely arbitrary and determined only by the protocol in use,
every parameter for a given connection has an entry in table
guacamole_connection_parameter
table associated with its
corresponding connection. This table contains the following columns:
- connection_id
The connection_id value from the connection this parameter is for.
- parameter_name
The name of the parameter to set. This is the name listed in the documentation for the protocol specified in the associated connection.
- parameter_value
The value to assign to the parameter named. While this value is an arbitrary string, it must conform to the requirements of the protocol as documented for the connection to be successful.
Adding a connection and corresponding parameters is relatively easy compared to adding a user as there is no salt to generate nor password to hash:
-- Create connection INSERT INTO guacamole_connection (connection_name, protocol) VALUES ('test
', 'vnc
'); -- Determine the connection_id SELECT * FROM guacamole_connection WHERE connection_name = 'test
' AND parent_id IS NULL; -- Add parameters to the new connection INSERT INTO guacamole_connection_parameter VALUES (1
, 'hostname', 'localhost
'); INSERT INTO guacamole_connection_parameter VALUES (1
, 'port', '5901
');
When a connection is initiated or terminated, a corresponding entry in the
guacamole_connection_history
table is created or
updated respectively. Each entry is associated with the user using the
connection, the connection itself, and the time the connection started. If the
connection has ended, the end time is also stored.
It is very unlikely that a user will need to update this table, but knowing
the structure is potentially useful if you wish to generate a report of
Guacamole usage. The guacamole_connection_history
table
has the following columns:
- history_id
The unique integer associated with each history record. This value is generated automatically when a new entry is inserted into the
guacamole_connection_history
table.- user_id
The value of the user_id from the entry in
guacamole_user
associated with the user using the connection.- connection_id
The value of the connection_id from the entry in
guacamole_connection
associated the connection being used.- start_date
The time at which the connection was started by the user specified. Despite its name, this column also stores time information in addition to the date.
- end_date
The time at which the connection ended. If the connection is still active, the value in this column will be
NULL
. Despite its name, this column also stores time information in addition to the date.
Each connection group has an entry in the
guacamole_connection_group
table, with a one-to-many
relationship to other groups and connections.
The guacamole_connection_group
table is simply a pairing of
a unique and descriptive name with a group type, which can be either
ORGANIZATIONAL or BALANCING. It contains the following
columns:
- connection_group_id
The unique integer associated with each connection group. This value is generated automatically when a new entry is inserted into the
guacamole_connection_group
table.- connection_group_name
The unique name associated with each connection group. This value must be specified manually, and must be different from any existing connection group name in the same connection group. References to connections in other tables use the value from connection_group_id, not connection_group_name.
- type
The type of this connection group. This can be either ORGANIZATIONAL or BALANCING.
- parent_id
The unique integer associated with the connection group containing this connection group, or
NULL
if this connection group is within the root group.
Adding a connection group is even simpler than adding a new connection as there are no associated parameters stored in a separate table:
-- Create connection group INSERT INTO guacamole_connection_group (connection_group_name, type) VALUES ('test
', 'ORGANIZATIONAL
');
There are three permissions tables in the schema which correspond to the three types of permissions in Guacamole's authentication model: system permissions, which control operations that affect the system as a whole, and user and connection permissions, which control operations that affect specific, existing users or connections respectively.
System permissions are defined by entries in the
guacamole_system_permission
table. Each entry grants
permission for a specific user to perform a specific system operation.
The guacamole_system_permission
table contains the
following columns:
- user_id
The value of the user_id column of the entry associated with the user owning this permission.
- permission
The permission being granted. This column can have one of three possible values:
ADMINISTER
, which grants the ability to administer the entire system (essentially a wildcard permission),CREATE_CONNECTION
, which grants the ability to create connections,CREATE_CONNECTION_GROUP
, which grants the ability to create connections groups, orCREATE_USER
, which grants the ability to create users.
User permissions are defined by entries in the
guacamole_user_permission
table. Each entry grants
permission for a specific user to perform a specific operation on another
existing user.
The guacamole_user_permission
table contains the
following columns:
- user_id
The value of the user_id column of the entry associated with the user owning this permission.
- affected_user_id
The value of the user_id column of the entry associated with the user affected by this permission. This is the user that would be the object of the operation represented by this permission.
- permission
The permission being granted. This column can have one of four possible values:
ADMINISTER
, which grants the ability to add or remove permissions which affect the user,READ
, which grants the ability to read data associated with the user,UPDATE
, which grants the ability to update data associated with the user, orDELETE
, which grants the ability to delete the user.
Connection permissions are defined by entries in the
guacamole_connection_permission
table. Each entry
grants permission for a specific user to perform a specific operation on an
existing connection.
The guacamole_connection_permission
table contains the
following columns:
- user_id
The value of the user_id column of the entry associated with the user owning this permission.
- connection_id
The value of the connection_id column of the entry associated with the connection affected by this permission. This is the connection that would be the object of the operation represented by this permission.
- permission
The permission being granted. This column can have one of four possible values:
ADMINISTER
, which grants the ability to add or remove permissions which affect the connection,READ
, which grants the ability to read data associated with the connection (a prerequisite for connecting),UPDATE
, which grants the ability to update data associated with the connection, orDELETE
, which grants the ability to delete the connection.
Connection group permissions are defined by entries in the
guacamole_connection_group_permission
table. Each
entry grants permission for a specific user to perform a specific operation on
an existing connection group.
The guacamole_connection_group_permission
table
contains the following columns:
- user_id
The value of the user_id column of the entry associated with the user owning this permission.
- connection_group_id
The value of the connection_group_id column of the entry associated with the connection group affected by this permission. This is the connection group that would be the object of the operation represented by this permission.
- permission
The permission being granted. This column can have one of four possible values:
ADMINISTER
, which grants the ability to add or remove permissions which affect the connection group,READ
, which grants the ability to read data associated with the connection group,UPDATE
, which grants the ability to update data associated with the connection group, orDELETE
, which grants the ability to delete the connection group (and implicitly its contents).