apache/docs/manual/mod/mod_auth_dbm.xml

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<!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
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<modulesynopsis>

<name>mod_auth_dbm</name>
<description>Provides for user authentication using DBM
    files</description>
<status>Extension</status>
<sourcefile>mod_auth_dbm.c</sourcefile>
<identifier>auth_dbm_module</identifier>

<summary>
    <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 <module>mod_auth</module>.</p>
</summary>

<seealso><directive module="core">AuthName</directive></seealso>
<seealso><directive module="core">AuthType</directive></seealso>
<seealso><directive module="core">Require</directive></seealso>
<seealso><directive module="core">Satisfy</directive></seealso>

<directivesynopsis>
<name>AuthDBMGroupFile</name>
<description>Sets the name of the database file containing the list
of user groups for authentication</description>
<syntax>AuthDBMGroupFile <em>file-path</em></syntax>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>

<usage>
    <p>The <directive>AuthDBMGroupFile</directive> 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
    <directive>AuthDBMGroupFile</directive> 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 <directive>AuthDBMGroupFile</directive> 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>

<example>
AuthDBMGroupFile /www/userbase<br />
AuthDBMUserFile /www/userbase
</example>

    <p>The key for the single DBM is the username. The value consists
    of</p>

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

    <p>The password section contains the Unix <code>crypt()</code>
    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>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthDBMUserFile</name>
<description>Sets thename of a database file containing the list of users and
passwords for authentication</description>
<syntax>AuthDBMUserFile <em>file-path</em></syntax>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>

<usage>
    <p>The <directive>AuthDBMUserFile</directive> 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 <code>crypt()</code> 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
    <directive>AuthDBMUserFile</directive> 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 <directive>AuthDBMUserFile</directive>.</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>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthDBMType</name>
<description>Sets the type of database file that is used to
store passwords</description>
<syntax>AuthDBMType default|SDBM|GDBM|DB</syntax>
<default>AuthDBMType default</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<compatibility>Available in version 2.0.30 and later.</compatibility>

<usage>

<p>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.</p>

<p>It is crucial that whatever program you use to create your password
files is configured to use the same type of database.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthDBMAuthoritative</name>
<description>Sets whether authentication and authorization will be
passwed on to lower level modules</description>
<syntax>AuthDBMAuthoritative on|off</syntax>
<default>AuthDBMAuthoritative on</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>

<usage>

<note>This information has not been updated to take into account the
new module ordering techniques in Apache 2.0</note>

    <p>Setting the <directive>AuthDBMAuthoritative</directive>
    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 <directive module="core">Require</directive>
    directive applies to more than one module; then the first module
    will verify the credentials; and no access is passed on;
    regardless of the <directive>AuthAuthoritative</directive> setting.</p>

    <p>A common use for this is in conjunction with one of the
    basic auth modules; such as <module>mod_auth</module>. 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 behaviour.</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>
</usage>
</directivesynopsis>

</modulesynopsis>