mod_authz_dbm Group authorization using DBM files Extension mod_authz_dbm.c authz_dbm_module

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
The Require Directives

Apache's Require directives are used during the authorization phase to ensure that a user is allowed to access a resource. mod_authz_dbm extends the authorization types with dbm-group.

Since v2.4.8, expressions are supported within the DBM require directives.

Require dbm-group

This directive specifies group membership that is required for the user to gain access.

Require dbm-group admin
Require dbm-file-group

When this directive is specified, the user must be a member of the group assigned to the file being accessed.

Require dbm-file-group
Example usage

Note that using mod_authz_dbm requires you to require dbm-group instead of group:

<Directory "/foo/bar"> AuthType Basic AuthName "Secure Area" AuthBasicProvider dbm AuthDBMUserFile "site/data/users" AuthDBMGroupFile "site/data/users" Require dbm-group admin </Directory>
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.