# Module mod_auth_db

This module provides for user authentication using Berkeley DB files.

Status: Extension
Source File: mod_auth_db.c
Module Identifier: db_auth_module

## Summary

This module provides an alternative to DBM files for those systems which support DB and not DBM. It is only available in Apache 1.1 and later.

On some BSD systems (e.g., FreeBSD and NetBSD) dbm is automatically mapped to Berkeley DB. You can use either mod_auth_dbm or mod_auth_db. The latter makes it more obvious that it's Berkeley DB. On other platforms where you want to use the DB library you usually have to install it first. See http://www.sleepycat.com/ for the distribution. The interface this module uses is the one from DB version 1.85 and 1.86, but DB version 2.x can also be used when compatibility mode is enabled.

## Directives

- AuthDBGroupFile
- AuthDBUserFile
- AuthDBAuthoritative

See also: satisfy and require.

## AuthDBGroupFile directive

Syntax: AuthDBGroupFile file-path
Context: directory, .htaccess
Override: AuthConfig
Status: Extension
Module: mod_auth_db

The AuthDBGroupFile directive sets the name of a DB file containing the list of user groups for user authentication. 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 AuthDBGroupFile 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 AuthDBGroupFile unless otherwise protected.

Combining Group and Password DB 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 DB file:

> `AuthDBGroupFile /www/userbase
> AuthDBUserFile /www/userbase`

The key for the single DB record is the username. The value consists of

> `Unix Crypt-ed Password : List of Groups [ : (ignored) ]`

The password section contains the Unix crypt() password as before. This is followed by a colon and the comma separated list of groups. Other data may optionally be left in the DB file after another colon; it is ignored by the authentication module.

See also AuthName, AuthType and AuthDBUserFile.

## AuthDBUserFile directive

Syntax: AuthDBUserFile file-path
Context: directory, .htaccess
Override: AuthConfig
Status: Extension
Module: mod_auth_db

The AuthDBUserFile directive sets the name of a DB file containing the list of users and passwords for user authentication. File-path is the absolute path to the user file.

The user file is keyed on the username. The value for a user is the crypt() encrypted password, optionally followed by a colon and arbitrary data. The colon and the data following it will be ignored by the server.

Security: make sure that the AuthDBUserFile 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 AuthDBUserFile.

Important compatibility note: The implementation of "dbmopen" in the apache modules reads the string length of the hashed values from the DB data structures, rather than relying upon the string being NULL-appended. Some applications, such as the Netscape web server, rely upon the string being NULL-appended, so if you are having trouble using DB files interchangeably between applications this may be a part of the problem.

A perl script called href="../programs/dbmmanage.html">dbmmanage is included with Apache. This program can be used to create and update DB format password files for use with this module.

See also AuthName, AuthType and AuthDBGroupFile.

## AuthDBAuthoritative directive

Syntax: AuthDBAuthoritative on|off
Default: `AuthDBAuthoritative on`
Context: directory, .htaccess
Override: AuthConfig
Status: Base
Module: mod_auth

Setting the AuthDBAuthoritative directive explicitly to 'off' allows for both authentication and authorization to be passed on to lower level modules (as defined in the `Configuration` and `modules.c` file if there is no userID or rule matching the supplied userID. If there is a userID and/or rule specified; the usual password and access checks will be applied and a failure will give an Authorization Required reply.

So if a userID appears in the database of more than one module; or if a valid `Require` directive applies to more than one module; then the first module will verify the credentials; and no access is passed on; regardless of the AuthAuthoritative setting.

A common use for this is in conjunction with one of the basic auth modules; such as `mod_auth.c`. Whereas this DB module supplies the bulk of the user credential checking; a few (administrator) related accesses fall through to a lower level with a well protected .htpasswd file.

By default, control is not passed on and an unknown userID or rule will result in an Authorization Required reply. Not setting it thus keeps the system secure and forces an NCSA compliant behaviour.

Security: Do consider the implications of allowing a user to allow fall-through in his .htaccess file; and verify that this is really what you want; Generally it is easier to just secure a single .htpasswd file, than it is to secure a database which might have more access interfaces.

See also AuthName, AuthType and AuthDBGroupFile.