Apache Module mod_authn_dbm

Description:	User authentication using DBM files
Status:	Extension
ModuleIdentifier:	authn_dbm_module
SourceFile:	mod_authn_dbm.c
Compatibility:	Available in Apache 2.1 and later

Summary

This module provides authentication front-ends such as mod_auth_digest and mod_auth_basic to authenticate users by looking up users in dbm password files. Similar functionality is provided by mod_authn_file.

When using mod_auth_basic or mod_auth_digest, this module is invoked via the AuthBasicProvider or AuthDigestProvider with the dbm value.

Bugfix checklist

AuthDBMType Directive

Description:	Sets the type of database file that is used to store passwords
Syntax:	`AuthDBMType default\|SDBM\|GDBM\|NDBM\|DB`
Default:	`AuthDBMType default`
Context:	directory, .htaccess
Override:	AuthConfig
Status:	Extension
Module:	mod_authn_dbm

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

For example, in order to enable the support for Berkeley DB (correspondent to the db type) the --with-berkeley-db option needs to be added to httpd's configure to generate the necessary DSO.

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

AuthDBMUserFile Directive

Description:	Sets the name of a database file containing the list of users and passwords for authentication
Syntax:	`AuthDBMUserFile file-path`
Context:	directory, .htaccess
Override:	AuthConfig
Status:	Extension
Module:	mod_authn_dbm

The AuthDBMUserFile directive sets the name of a DBM 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 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 AuthDBMUserFile 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 AuthDBMUserFile.

The encrypted password format depends on which authentication frontend (e.g. mod_auth_basic or mod_auth_digest) is being used. See Password Formats for more information.

Important compatibility note: The implementation of dbmopen in the Apache modules reads the string length of the hashed values from the DBM 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 DBM files interchangeably between applications this may be a part of the problem.

A perl script called dbmmanage is included with Apache. This program can be used to create and update DBM format password files for use with this module. Another tool for maintaining the DBM files is the included program htdbm.