Apache HTTP Server Version 2.3
-
Apache HTTP Server Version 2.3
-Apache HTTP Server Version 2.5
+
| Description: | Form authentication |
|---|---|
| Status: | Base |
| Module Identifier: | auth_form_module |
| Source File: | mod_auth_form.c |
Once the user has been successfully authenticated, the user's login
details will be stored in a session provided by mod_session.
Basic Configuration Standalone Login Inline Login Inline Login with Body Preservation Logging Out Usernames and Passwords AuthFormAuthoritative AuthFormBody AuthFormSize AuthFormUsername Basic Configuration Standalone Login Inline Login Inline Login with Body Preservation Logging Out
To protect a particular URL with mod_auth_form, you need to
decide where you will store your session, and you will need to
decide what method you will use to authenticate. In this simple example, the
@@ -101,25 +108,24 @@
mod_session_cookie, and authentication will be attempted against
a file using mod_authn_file. If authentication is unsuccessful,
the user will be redirected to the form login page.
- AuthFormProvider file
- AuthUserFile conf/passwd
- AuthType form
- AuthName realm
- AuthFormLoginRequiredLocation http://example.com/login.html
- Session On
- SessionCookieName session path=/
- SessionCryptoPassphrase secret
-
AuthFormProvider file +AuthUserFile "conf/passwd" +AuthType form +AuthName realm +AuthFormLoginRequiredLocation "http://example.com/login.html" +Session On +SessionCookieName session path=/ +SessionCryptoPassphrase secret+
The directive AuthType will enable
the mod_auth_form authentication when set to the value form.
The directives AuthFormProvider and
AuthUserFile specify that usernames
and passwords should be checked against the chosen file.
The directives Session,
+
The directives Session,
SessionCookieName and
SessionCryptoPassphrase create an
encrypted session stored within an HTTP cookie on the browser. For more information
@@ -137,69 +143,62 @@
The login form can be hosted as a standalone page, or can be provided inline on the same page.
- +When configuring the login as a standalone page, unsuccessful authentication
attempts should be redirected to a login form created by the website for this purpose,
using the AuthFormLoginRequiredLocation
directive. Typically this login page will contain an HTML form, asking the user to
provide their usename and password.
- <form method="POST" action="/dologin.html">
- Username: <input type="text" name="httpd_username" value="" />
- Password: <input type="password" name="httpd_password" value="" />
- <input type="submit" name="login" value="Login" />
- </form>
-
<form method="POST" action="/dologin.html"> + Username: <input type="text" name="httpd_username" value="" /> + Password: <input type="password" name="httpd_password" value="" /> + <input type="submit" name="login" value="Login" /> +</form>+
The part that does the actual login is handled by the form-login-handler. The action of the form should point at this handler, which is configured within - Apache as follows:
- -
- <Location /dologin.html>
-
- SetHandler form-login-handler
- AuthFormLoginRequiredLocation http://example.com/login.html
- AuthFormLoginSuccessLocation http://example.com/success.html
- AuthFormProvider file
- AuthUserFile conf/passwd
- AuthType form
- AuthName realm
- Session On
- SessionCookieName session path=/
- SessionCryptoPassphrase secret
-
- </Location>
-
<Location "/dologin.html"> + SetHandler form-login-handler + AuthFormLoginRequiredLocation "http://example.com/login.html" + AuthFormLoginSuccessLocation "http://example.com/success.html" + AuthFormProvider file + AuthUserFile "conf/passwd" + AuthType form + AuthName realm + Session On + SessionCookieName session path=/ + SessionCryptoPassphrase secret +</Location>+
The URLs specified by the
AuthFormLoginRequiredLocation directive will typically
point to a page explaining to the user that their login attempt was unsuccessful, and they
should try again. The AuthFormLoginSuccessLocation
directive specifies the URL the user should be redirected to upon successful login.
Alternatively, the URL to redirect the user to on success can be embedded within the login form, as in the example below. As a result, the same form-login-handler can be reused for different areas of a website.
-
- <form method="POST" action="/dologin.html">
-
- Username: <input type="text" name="httpd_username" value="" />
- Password: <input type="password" name="httpd_password" value="" />
- <input type="submit" name="login" value="Login" />
- <input type="hidden" name="httpd_location" value="http://example.com/success.html" />
-
- </form>
-
<form method="POST" action="/dologin.html"> + Username: <input type="text" name="httpd_username" value="" /> + Password: <input type="password" name="httpd_password" value="" /> + <input type="submit" name="login" value="Login" /> + <input type="hidden" name="httpd_location" value="http://example.com/success.html" /> +</form>+
A risk exists that under certain circumstances, the login form configured +
A risk exists that under certain circumstances, the login form configured
using inline login may be submitted more than once, revealing login credentials to
the application running underneath. The administrator must ensure that the underlying
application is properly secured to prevent abuse. If in doubt, use the
@@ -218,37 +217,33 @@
AuthFormLoginRequiredLocation directive,
a HTTP_UNAUTHORIZED status code is returned to the browser indicating to the user
that they are not authorized to view the page.
To configure inline authentication, the administrator overrides the error document returned by the HTTP_UNAUTHORIZED status code with a custom error document containing the login form, as follows:
-
- AuthFormProvider file
- ErrorDocument 401 /login.shtml
- AuthUserFile conf/passwd
- AuthType form
- AuthName realm
- AuthFormLoginRequiredLocation http://example.com/login.html
- Session On
- SessionCookieName session path=/
- SessionCryptoPassphrase secret
-
AuthFormProvider file +ErrorDocument 401 "/login.shtml" +AuthUserFile "conf/passwd" +AuthType form +AuthName realm +AuthFormLoginRequiredLocation "http://example.com/login.html" +Session On +SessionCookieName session path=/ +SessionCryptoPassphrase secret+
The error document page should contain a login form with an empty action property, as per the example below. This has the effect of submitting the form to the original protected URL, without the page having to know what that URL is.
-
- <form method="POST" action="">
-
- Username: <input type="text" name="httpd_username" value="" />
- Password: <input type="password" name="httpd_password" value="" />
- <input type="submit" name="login" value="Login" />
-
- </form>
-
<form method="POST" action=""> + Username: <input type="text" name="httpd_username" value="" /> + Password: <input type="password" name="httpd_password" value="" /> + <input type="submit" name="login" value="Login" /> +</form>+
When the end user has filled in their login details, the form will make an HTTP POST request to the original password protected URL. @@ -270,41 +265,37 @@
mod_auth_form addresses this by allowing the method and body
of the original request to be embedded in the login form. If authentication
- is successful, the original method and body will be retried by Apache, preserving
+ is successful, the original method and body will be retried by Apache httpd, preserving
the state of the original request.
To enable body preservation, add three additional fields to the login form as per the example below.
-
- <form method="POST" action="">
-
- Username: <input type="text" name="httpd_username" value="" />
- Password: <input type="password" name="httpd_password" value="" />
- <input type="submit" name="login" value="Login" />
- <input type="hidden" name="httpd_method" value="POST" />
- <input type="hidden" name="httpd_mimetype" value="application/x-www-form-urlencoded" />
- <input type="hidden" name="httpd_body" value="name1=value1&name2=value2" />
-
- </form>
-
<form method="POST" action=""> + Username: <input type="text" name="httpd_username" value="" /> + Password: <input type="password" name="httpd_password" value="" /> + <input type="submit" name="login" value="Login" /> ++
<input type="hidden" name="httpd_method" value="POST" /> + <input type="hidden" name="httpd_mimetype" value="application/x-www-form-urlencoded" /> + <input type="hidden" name="httpd_body" value="name1=value1&name2=value2" />
+</form>
How the method, mimetype and body of the original request are embedded within the login form will depend on the platform and technology being used within the website.
One option is to use the mod_include module along with the
- KeptBodySize directive, along with a suitable
+ KeptBodySize directive, along with a suitable
CGI script to embed the variables in the form.
Another option is to render the login form using a CGI script or other dynamic technology.
-
- AuthFormProvider file
- ErrorDocument 401 /cgi-bin/login.cgi
- ...
-
AuthFormProvider file + ErrorDocument 401 "/cgi-bin/login.cgi" + ...+
- SetHandler form-logout-handler
- AuthName realm
- AuthFormLogoutLocation http://example.com/loggedout.html
- Session On
- SessionCookieName session path=/
- SessionCryptoPassphrase secret
-
SetHandler form-logout-handler +AuthName realm +AuthFormLogoutLocation "http://example.com/loggedout.html" +Session On +SessionCookieName session path=/ +SessionCryptoPassphrase secret+
Note that logging a user out does not delete the session; it merely removes the username and password from the session. If this results in an empty session, @@ -338,15 +328,21 @@ value, like 1 (setting the directive to zero would mean no session age limit).
-
- SetHandler form-logout-handler
- AuthFormLogoutLocation http://example.com/loggedout.html
- Session On
- SessionMaxAge 1
- SessionCookieName session path=/
- SessionCryptoPassphrase secret
-
SetHandler form-logout-handler +AuthFormLogoutLocation "http://example.com/loggedout.html" +Session On +SessionMaxAge 1 +SessionCookieName session path=/ +SessionCryptoPassphrase secret+
Note that form submission involves URLEncoding the form data: + in this case the username and password. You should therefore + pick usernames and passwords that avoid characters that are + URLencoded in form submission, or you may get unexpected results.
The AuthFormMethod directive specifies
the name of an HTML field which, if present, will contain the method of the request to
to submit should login be successful.
By populating the form with fields described by
- AuthFormMethod,
+ AuthFormMethod,
AuthFormMimetype and
AuthFormBody, a website can retry
a request that may have been interrupted by the login screen, or by a session
@@ -406,12 +402,12 @@ lower level modules
The AuthFormDisableNoStore flag
disables the sending of a Cache-Control no-store header with the
error 401 page returned when the user is not yet logged in. The purpose of the header
- is to make it difficult for an ecmascript application to attempt to resubmit the
+ is to make it difficult for an ecmascript application to attempt to resubmit the
login form, and reveal the username and password to the backend application. Disable
at your own risk.
The AuthFormFakeBasicAuth flag
determines whether a Basic Authentication header will be added to
@@ -445,7 +441,7 @@ lower level modules
The AuthFormLocation directive specifies
the name of an HTML field which, if present, will contain a URL to redirect the browser to
@@ -461,15 +457,17 @@ lower level modules
The AuthFormLoginRequiredLocation directive
- specifies the URL to redirect to should the user not be authorised to view a page. By default,
- if a user is not authorised to view a page, the HTTP response code HTTP_UNAUTHORIZED
- will be returned with the page specified by the
+ specifies the URL to redirect to should the user not be authorised to view a page. The value
+ is parsed using the ap_expr parser before being sent to the client.
+ By default, if a user is not authorised to view a page, the HTTP response code
+ HTTP_UNAUTHORIZED will be returned with the page specified by the
ErrorDocument directive. This directive overrides this
default.
Use this directive if you have a dedicated login page to redirect users to.
@@ -483,13 +481,15 @@ lower level modulesThe AuthFormLoginSuccessLocation directive
- specifies the URL to redirect to should the user have logged in successfully. This directive
- can be overridden if a form field has been defined containing another URL using the
- AuthFormLocation directive.
AuthFormLocation directive.
+
Use this directive if you have a dedicated login URL, and you have not embedded the destination page in the login form.
@@ -504,25 +504,25 @@ lower level modulesThe AuthFormLogoutLocation directive
- specifies the URL of a page on the server to redirect to should the user attempt to log out.
When a URI is accessed that is served by the handler form-logout-handler,
the page specified by this directive will be shown to the end user. For example:
- <Location /logout>
-
- SetHandler form-logout-handler
- AuthFormLogoutLocation http://example.com/loggedout.html
- Session on
- ...
-
- </Location>
-
<Location "/logout"> + SetHandler form-logout-handler + AuthFormLogoutLocation "http://example.com/loggedout.html" + Session on + #... +</Location>+
An attempt to access the URI /logout/ will result in the user being logged out, and the page /loggedout.html will be displayed. Make sure that the page loggedout.html is not password protected, otherwise the page will not be @@ -539,14 +539,14 @@ lower level modules
The AuthFormMethod directive specifies
the name of an HTML field which, if present, will contain the method of the request to
to submit should login be successful.
By populating the form with fields described by
- AuthFormMethod,
+ AuthFormMethod,
AuthFormMimetype and
AuthFormBody, a website can retry
a request that may have been interrupted by the login screen, or by a session
@@ -562,14 +562,14 @@ lower level modules
The AuthFormMethod directive specifies
the name of an HTML field which, if present, will contain the
- mimetype of the request to to submit should login be successful.
By populating the form with fields described by
- AuthFormMethod,
+ AuthFormMethod,
AuthFormMimetype and
AuthFormBody, a website can retry
a request that may have been interrupted by the login screen, or by a session
@@ -585,7 +585,7 @@ lower level modules
The AuthFormPassword directive specifies
the name of an HTML field which, if present, will contain the password to be used to log
@@ -604,29 +604,26 @@ lower level modules
The AuthFormProvider directive sets
+
The AuthFormProvider directive sets
which provider is used to authenticate the users for this location.
The default file provider is implemented
by the mod_authn_file module. Make sure
that the chosen provider module is present in the server.
- <Location /secure>
-
- AuthType form
- AuthName "private area"
- AuthFormProvider dbm
- AuthDBMType SDBM
- AuthDBMUserFile /www/etc/dbmpasswd
- Require valid-user
- ...
-
- </Location>
-
<Location "/secure"> + AuthType form + AuthName "private area" + AuthFormProvider dbm + AuthDBMType SDBM + AuthDBMUserFile "/www/etc/dbmpasswd" + Require valid-user + #... +</Location>+
Providers are implemented by mod_authn_dbm,
mod_authn_file, mod_authn_dbd,
- and mod_authnz_ldap.
mod_authnz_ldap and mod_authn_socache.
The AuthFormSitePassphrase directive
- specifies a passphrase which, if present in the user session, causes Apache to
+ specifies a passphrase which, if present in the user session, causes Apache httpd to
bypass authentication checks for the given URL. It can be used on high traffic websites
to reduce the load induced on authentication infrastructure.
The passphrase can be inserted into a user session by adding this directive to the configuration for the form-login-handler. The form-login-handler itself will always run the authentication checks, regardless of whether a passphrase @@ -665,24 +662,24 @@ lower level modules
| Description: | The largest size of the form in bytes that will be parsed for the login details |
|---|---|
| Syntax: | AuthFormBody size |
| Syntax: | AuthFormSize size |
| Default: | 8192 |
| Context: | directory |
| Status: | Base |
| Module: | mod_auth_form |
| Compatibility: | Available in Apache 2.3.0 and later |
| Compatibility: | Available in Apache HTTP Server 2.3.0 and later |
The AuthFormSize directive specifies
the maximum size of the body of the request that will be parsed to find the login form.
If a login request arrives that exceeds this size, the whole request will be aborted
with the HTTP response code HTTP_REQUEST_TOO_LARGE.
If you have populated the form with fields described by
- AuthFormMethod,
+ AuthFormMethod,
AuthFormMimetype and
AuthFormBody, you probably want to set this
- field to a similar size as the KeptBodySize
+ field to a similar size as the KeptBodySize
directive.
The AuthFormUsername directive specifies
the name of an HTML field which, if present, will contain the username to be used to log
@@ -705,8 +702,30 @@ lower level modules
Available Languages: en
-