mod_authz_dbd
Group Authorization and Login using SQL
Extension
mod_authz_dbd.c
authz_dbd_module
Available in Apache 2.4 and later
This module provides authorization capabilities so that
authenticated users can be allowed or denied access to portions
of the web site by group membership. Similar functionality is
provided by mod_authz_groupfile and
mod_authz_dbm, with the exception that
this module queries a SQL database to determine whether a
user is a member of a group.
This module can also provide database-backed user login/logout
capabilities. These are likely to be of most value when used
in conjunction with mod_authn_dbd.
This module relies on mod_dbd to specify
the backend database driver and connection parameters, and
manage the database connections.
Require
AuthDBDUserPWQuery
DBDriver
DBDParams
Database Login
In addition to the standard authorization function of checking group
membership, this module can also provide server-side user session
management via database-backed login/logout capabilities.
Specifically, it can update a user's session status in the database
whenever the user visits designated URLs (subject of course to users
supplying the necessary credentials).
This works by defining two special
Require types:
Require dbd-login
and Require dbd-logout
.
For usage details, see the configuration example below.
Client Login
Some administrators may wish to implement client-side session
management that works in concert with the server-side login/logout
capabilities offered by this module, for example, by setting or unsetting
an HTTP cookie or other such token when a user logs in or out.
To support such integration, mod_authz_dbd exports an
optional hook that will be run whenever a user's status is updated in
the database. Other session management modules can then use the hook
to implement functions that start and end client-side sessions.
Configuration example
# mod_dbd configuration
DBDriver pgsql
DBDParams "dbname=apacheauth user=apache pass=xxxxxx"
DBDMin 4
DBDKeep 8
DBDMax 20
DBDExptime 300
<Directory /usr/www/my.site/team-private/>
# mod_authn_core and mod_auth_basic configuration
# for mod_authn_dbd
AuthType Basic
AuthName Team
AuthBasicProvider dbd
# mod_authn_dbd SQL query to authenticate a logged-in user
AuthDBDUserPWQuery \
"SELECT password FROM authn WHERE user = %s AND login = 'true'"
# mod_authz_core configuration for mod_authz_dbd
Require dbd-group team
# mod_authz_dbd configuration
AuthzDBDQuery "SELECT group FROM authz WHERE user = %s"
# when a user fails to be authenticated or authorized,
# invite them to login; this page should provide a link
# to /team-private/login.html
ErrorDocument 401 /login-info.html
<Files login.html>
# don't require user to already be logged in!
AuthDBDUserPWQuery "SELECT password FROM authn WHERE user = %s"
# dbd-login action executes a statement to log user in
Require dbd-login
AuthzDBDQuery "UPDATE authn SET login = 'true' WHERE user = %s"
# return user to referring page (if any) after
# successful login
AuthzDBDLoginToReferer On
</Files>
<Files logout.html>
# dbd-logout action executes a statement to log user out
Require dbd-logout
AuthzDBDQuery "UPDATE authn SET login = 'false' WHERE user = %s"
</Files>
</Directory>
AuthzDBDQuery
Specify the SQL Query for the required operation
AuthzDBDQuery query
directory
The AuthzDBDQuery specifies an SQL
query to run. The purpose of the query depends on the
Require directive in
effect.
- When used with a
Require dbd-group
directive,
it specifies a query to look up groups for the current user. This is
the standard functionality of other authorization modules such as
mod_authz_groupfile and mod_authz_dbm.
The first column value of each row returned by the query statement
should be a string containing a group name. Zero, one, or more rows
may be returned.
Require dbd-group
AuthzDBDQuery "SELECT group FROM groups WHERE user = %s"
- When used with a
Require dbd-login
or
Require dbd-logout
directive, it will never deny access,
but will instead execute a SQL statement designed to log the user
in or out. The user must already be authenticated with
mod_authn_dbd.
Require dbd-login
AuthzDBDQuery "UPDATE authn SET login = 'true' WHERE user = %s"
In all cases, the user's ID will be passed as a single string
parameter when the SQL query is executed. It may be referenced within
the query statement using a %s
format specifier.
AuthzDBDRedirectQuery
Specify a query to look up a login page for the user
AuthzDBDRedirectQuery query
directory
Specifies an optional SQL query to use after successful login
(or logout) to redirect the user to a URL, which may be
specific to the user. The user's ID will be passed as a single string
parameter when the SQL query is executed. It may be referenced within
the query statement using a %s
format specifier.
AuthzDBDRedirectQuery "SELECT userpage FROM userpages WHERE user = %s"
The first column value of the first row returned by the query
statement should be a string containing a URL to which to redirect
the client. Subsequent rows will be ignored. If no rows are returned,
the client will not be redirected.
Note that AuthzDBDLoginToReferer takes
precedence if both are set.
AuthzDBDLoginToReferer
Determines whether to redirect the Client to the Referring
page on successful login or logout if a Referer
request
header is present
AuthzDBDLoginToReferer On|Off
AuthzDBDLoginToReferer Off
directory
In conjunction with Require dbd-login
or
Require dbd-logout
, this provides the option to
redirect the client back to the Referring page (the URL in
the Referer
HTTP request header, if present).
When there is no Referer
header,
AuthzDBDLoginToReferer On
will be ignored.