mod_authz_dbm
Group authorization using DBM files
Extension
mod_authz_dbm.c
authz_dbm_module
Available in Apache 2.1 and later

This module provides authorization capabilities so that authenticated users can be allowed or denied access to portions of the web site by group membership. Similar functionality is provided by mod_authz_groupfile.

Require
AuthDBMGroupFile
Sets the name of the database file containing the list of user groups for authorization
AuthDBMGroupFile file-path
directory
.htaccess
AuthConfig

The AuthDBMGroupFile directive sets the name of a DBM file containing the list of user groups for user authorization. File-path is the absolute path to the group file.

The group file is keyed on the username. The value for a user is a comma-separated list of the groups to which the users belongs. There must be no whitespace within the value, and it must never contain any colons.

# Security

Make sure that the AuthDBMGroupFile is stored outside the document tree of the web-server. Do not put it in the directory that it protects. Otherwise, clients will be able to download the AuthDBMGroupFile unless otherwise protected.

Combining Group and Password DBM files: In some cases it is easier to manage a single database which contains both the password and group details for each user. This simplifies any support programs that need to be written: they now only have to deal with writing to and locking a single DBM file. This can be accomplished by first setting the group and password files to point to the same DBM:

AuthDBMGroupFile /www/userbase
AuthDBMUserFile /www/userbase

The key for the single DBM is the username. The value consists of

Encrypted Password : List of Groups [ : (ignored) ]

The password section contains the encrypted password as before. This is followed by a colon and the comma separated list of groups. Other data may optionally be left in the DBM file after another colon; it is ignored by the authorization module. This is what www.telescope.org uses for its combined password and group database.

AuthzDBMType
Sets the type of database file that is used to store list of user groups
AuthzDBMType default|SDBM|GDBM|NDBM|DB
AuthzDBMType default
directory
.htaccess
AuthConfig

Sets the type of database file that is used to store the list of user groups. The default database type is determined at compile time. The availability of other types of database files also depends on compile-time settings.

It is crucial that whatever program you use to create your group files is configured to use the same type of database.