Apache HTTP Server Version 2.4

Apache > HTTP Server > Documentation > Version 2.4 > Modules

# Apache Module mod_authz_dbm

Description: | Group authorization using DBM files
Status: | Extension
Module Identifier: | authz_dbm_module
Source File: | mod_authz_dbm.c
Compatibility: | Available in Apache 2.1 and later

### Summary

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`.

### Topics

- The Require Directives
- Example usage

### Directives

### Bugfix checklist

- httpd changelog
- Known issues
- Report a bug

### See also

- `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 Directive

Description: | Sets the name of the database file containing the list of user groups for authorization
Syntax: | `AuthDBMGroupFile file-path`
Context: | directory, .htaccess
Override: | AuthConfig
Status: | Extension
Module: | mod_authz_dbm

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 Directive

Description: | Sets the type of database file that is used to store list of user groups
Syntax: | `AuthzDBMType default|SDBM|GDBM|NDBM|DB`
Default: | `AuthzDBMType default`
Context: | directory, .htaccess
Override: | AuthConfig
Status: | Extension
Module: | mod_authz_dbm

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.