Introduction to Authentication for Trac

This is a work in progress document - and is written by someone who has been working this stuff out, rather than an expert. Please feel free to add clarifications, corrections and additions

The basic idea is that Trac itself does not do authentication (other than for tracd which I don't intend to cover here). Authentication is done by the http daemon environment, and the authentication information passed to trac when it is invoked by the httpd.

There are 2 basic approaches to Trac authentication:-

1. Restrict access to the whole Trac installation, so that none of the trac pages are visible without authentication.
2. Restrict access such that the Trac installation is visible to someone without authentication, but you can login with Trac.

The following examples are based on an Apache httpd server - further information on authentication on Apache can be found at ​http://httpd.apache.org/docs-2.0/howto/auth.html

They use a password file at /var/www/db/passwd - you will need to manipulate this with the htpasswd program or you could look at ​http://stein.cshl.org/~lstein/user_manage/ As an alternative you could drop in digest authentication - the Apache documentation describes this.

Require Authentication To Access The Trac Installation

This is the simplest method in both concept and implementation. It also allows you to know that your data is as secure as your web server authentication scheme and that there is a degree of trust in the user information entered on tickets etc.

For a trac installation under /var/www/trac, visible as URL http://www.example.com/trac/ you can use an authenticaton stanza for Apache similar to:-

<Location /trac>
  AuthType Basic
  AuthName "trac"
  AuthUserFile /var/www/db/passwd
  Require valid-user
  ... extra directives to invoke trac
  ... - ie ScriptAlias or mod_python stuff
</Location>

Optional Authentication For The Trac Installation

This method of authentication allows unauthenticated users to see and to make (limited) changes to the Trac system. Authenticated users have a bit more access. To login you click on the Login entry on the top menubar; after authentication you are given a cookie which is used for authorization and access control.

To do this you need to control access to the login name under the Traq system, so for the example above you would change the configuration to:-

<Location /trac>
  ... extra directives to invoke trac
  ... - ie ScriptAlias or mod_python stuff
</Location>
<Location /trac/login>
  AuthType Basic
  AuthName "trac"
  AuthUserFile /var/www/db/passwd
  Require valid-user
</Location>

Issues

You really do want your subversion repository to be using the same names as the Trac authentication names so that labelling of changesets matches with names assigned to tickets etc. This means there is a great advantage in using DAV access to the subversion database and sharing the authentication (password) files between Trac and the WebDAV areas (maybe using group access to give a subset of the users access to the subversion database), although this can be done in other ways.

In the authentication methods shown here the password travels in clear over the network. You can use Digest authentication to prevent the clear text password going over the network, but this can still be sniffed and replayed. If you require greater security then you really should use SSL for encryption, or another means of access control.