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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"
<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
<h2>Directives</h2>
<ul>
<LI><A HREF="#authdbmgroupfile">AuthDBMGroupFile</A>
<LI><A HREF="#authdbmuserfile">AuthDBMUserFile</A>
<LI><A HREF="#authdbmauthoritative">AuthDBMAuthoritative</A>
</ul>
<HR>
<H2><A NAME="authdbmgroupfile">AuthDBMGroupFile</A></H2>
<!--%plaintext <?INDEX {\tt AuthDBMGroupFile} directive> -->
<A
HREF="directive-dict.html#Syntax"
REL="Help"
><STRONG>Syntax:</STRONG></A> AuthDBMGroupFile <EM>filename</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>Filename</EM> is the absolute path
to the group file.<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>
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>
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>
</CODE></BLOCKQUOTE>
The key for the single DBM is the username. The value consists of <P>
<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>
<A HREF="#authdbmuserfile">AuthDBMUserFile</A>.<P><HR>
<H2><A NAME="authdbmuserfile">AuthDBMUserFile</A></H2>
<!--%plaintext <?INDEX {\tt AuthDBMUserFile} directive> -->
<A
HREF="directive-dict.html#Syntax"
REL="Help"
><STRONG>Syntax:</STRONG></A> AuthDBMUserFile <EM>filename</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>Filename</EM> is the
absolute path to the user file.<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>
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>
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>
<A HREF="#authdbmgroupfile">AuthDBMGroupFile</A>.<P>
<HR>
<H2><A NAME="authdbmauthoritative">AuthDBMAuthoritative</A></H2>
<!--%plaintext <?INDEX {\tt AuthDBMAuthoritative} directive> -->
<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>
<STRONG>rule</STRONG> matching the supplied userID. If there is a userID
be applied and a failure will give an Authorization Required reply.
<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>
A common use for this is in conjunction with one of the basic 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. <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>
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>
<A HREF="#authdbmgroupfile">AuthDBMGroupFile</A>.<P>
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