Apache HTTP Server Version 2.0
Apache HTTP Server Version 2.0
This document refers to the 2.0 version of Apache httpd, which is no longer maintained. Upgrade, and refer to the current version of httpd instead, documented at:
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| Description: | Provides for user authentication using DBM files |
|---|---|
| Status: | Extension |
| Module Identifier: | auth_dbm_module |
| Source File: | mod_auth_dbm.c |
| Compatibility: | Available only in versions prior to 2.1 |
This module provides for HTTP Basic Authentication, where
the usernames and passwords are stored in DBM type database
files. It is an alternative to the plain text password files
provided by mod_auth.
| Description: | Sets whether authentication and authorization will be passed on to lower level modules |
|---|---|
| Syntax: | AuthDBMAuthoritative On|Off |
| Default: | AuthDBMAuthoritative On |
| Context: | directory, .htaccess |
| Override: | AuthConfig |
| Status: | Extension |
| Module: | mod_auth_dbm |
Setting the AuthDBMAuthoritative
directive explicitly to Off allows for both
authentication and authorization to be passed on to lower level
modules (as defined in the modules.c files) 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 "Authentication 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 AuthDBMAuthoritative
setting.
A common use for this is in conjunction with one of the
basic auth modules; such as mod_auth. Whereas this
DBM 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 "Authentication Required" reply. Not setting it thus keeps the system secure and forces an NCSA compliant behaviour.
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.
| Description: | Sets the name of the database file containing the list of user groups for authentication |
|---|---|
| Syntax: | AuthDBMGroupFile file-path |
| Context: | directory, .htaccess |
| Override: | AuthConfig |
| Status: | Extension |
| Module: | mod_auth_dbm |
The AuthDBMGroupFile directive sets the
name of a DBM 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
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
Unix Crypt-ed 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 authentication module. This is what www.telescope.org uses for its combined password and group database.
| 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_auth_dbm |
| Compatibility: | Available in version 2.0.30 and later. |
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.
It is crucial that whatever program you use to create your password files is configured to use the same type of database.
| Description: | Sets thename 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_auth_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.
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.
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.
