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    <title>Apache module mod_auth_dbm</title>
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    <h1 align="CENTER">Module mod_auth_dbm</h1>

    <p>This module provides for user authentication using DBM
    files.</p>

    <p><a href="module-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Extension<br />
     <a href="module-dict.html#SourceFile"
    rel="Help"><strong>Source File:</strong></a>
    mod_auth_dbm.c<br />
     <a href="module-dict.html#ModuleIdentifier"
    rel="Help"><strong>Module Identifier:</strong></a>
    dbm_auth_module</p>

    <h2>Summary</h2>

    <p>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 <a href="mod_auth.html">mod_auth</a> and the
    Berkely DB password files provided by <a
    href="mod_auth_db.html">mod_auth_db</a>.</p>

    <h2>Directives</h2>

    <ul>
      <li><a href="#authdbmgroupfile">AuthDBMGroupFile</a></li>

      <li><a href="#authdbmuserfile">AuthDBMUserFile</a></li>

      <li><a
      href="#authdbmauthoritative">AuthDBMAuthoritative</a></li>
    </ul>

    <p>See also: <a href="core.html#satisfy">Satisfy</a> and <a
    href="core.html#require">Require</a>.</p>
    <hr />

    <h2><a id="authdbmgroupfile"
    name="authdbmgroupfile">AuthDBMGroupFile</a></h2>
    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthDBMGroupFile
    <em>file-path</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Extension<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_auth_dbm 

    <p>The AuthDBMGroupFile directive sets the name of a DBM file
    containing the list of user groups for user authentication.
    <em>File-path</em> is the absolute path to the group file.</p>

    <p>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.</p>

    <p>Security: make sure that the AuthDBMGroupFile is stored
    outside the document tree of the web-server; do <em>not</em>
    put it in the directory that it protects. Otherwise, clients
    will be able to download the AuthDBMGroupFile unless otherwise
    protected.</p>

    <p>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:</p>

    <blockquote>
      <code>AuthDBMGroupFile /www/userbase<br />
       AuthDBMUserFile /www/userbase</code>
    </blockquote>
    The key for the single DBM is the username. The value consists
    of 

    <blockquote>
      <code>Unix Crypt-ed Password : List of Groups [ : (ignored)
      ]</code>
    </blockquote>
    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 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. 

    <p>See also <a href="core.html#authname">AuthName</a>, <a
    href="core.html#authtype">AuthType</a> and <a
    href="#authdbmuserfile">AuthDBMUserFile</a>.</p>
    <hr />

    <h2><a id="authdbmuserfile"
    name="authdbmuserfile">AuthDBMUserFile</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthDBMUserFile
    <em>file-path</em><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Extension<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_auth_dbm 

    <p>The AuthDBMUserFile directive sets the name of a DBM file
    containing the list of users and passwords for user
    authentication. <em>File-path</em> is the absolute path to the
    user file.</p>

    <p>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.</p>

    <p>Security: make sure that the AuthDBMUserFile is stored
    outside the document tree of the web-server; do <em>not</em>
    put it in the directory that it protects. Otherwise, clients
    will be able to download the AuthDBMUserFile.</p>

    <p>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.</p>

    <p>A perl script called <a
    href="../programs/dbmmanage.html">dbmmanage</a> is included
    with Apache. This program can be used to create and update DBM
    format password files for use with this module.</p>
    See also <a href="core.html#authname">AuthName</a>, <a
    href="core.html#authtype">AuthType</a> and <a
    href="#authdbmgroupfile">AuthDBMGroupFile</a>. 
    <hr />

    <h2><a id="authdbmauthoritative"
    name="authdbmauthoritative">AuthDBMAuthoritative</a></h2>

    <a href="directive-dict.html#Syntax"
    rel="Help"><strong>Syntax:</strong></a> AuthDBMAuthoritative
    on|off<br />
     <a href="directive-dict.html#Default"
    rel="Help"><strong>Default:</strong></a>
    <code>AuthDBMAuthoritative on</code><br />
     <a href="directive-dict.html#Context"
    rel="Help"><strong>Context:</strong></a> directory,
    .htaccess<br />
     <a href="directive-dict.html#Override"
    rel="Help"><strong>Override:</strong></a> AuthConfig<br />
     <a href="directive-dict.html#Status"
    rel="Help"><strong>Status:</strong></a> Extension<br />
     <a href="directive-dict.html#Module"
    rel="Help"><strong>Module:</strong></a> mod_auth_dbm 

    <p>Setting the AuthDBMAuthoritative directive explicitly to
    <strong>'off'</strong> allows for both authentication and
    authorization to be passed on to lower level modules (as
    defined in the <code>Configuration</code> and
    <code>modules.c</code> file if there is <strong>no
    userID</strong> or <strong>rule</strong> 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.</p>

    <p>So if a userID appears in the database of more than one
    module; or if a valid <code>Require</code> 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.</p>

    <p>A common use for this is in conjunction with one of the
    basic auth modules; such as <a
    href="mod_auth.html"><code>mod_auth.c</code></a>. 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.</p>

    <p>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 behavior.</p>

    <p>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.</p>

    <p>See also <a href="core.html#authname">AuthName</a>, <a
    href="core.html#authtype">AuthType</a> and <a
    href="#authdbmgroupfile">AuthDBMGroupFile</a>.</p>

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