Apache Module mod_info

Security Issues

Once mod_info is loaded into the server, its handler capability is available in all configuration files, including per-directory files (e.g., .htaccess). This may have security-related ramifications for your site.

In particular, this module can leak sensitive information from the configuration directives of other Apache modules such as system paths, usernames/passwords, database names, etc. Therefore, this module should only be used in a controlled environment and always with caution.

You will probably want to use mod_authz_host to limit access to your server configuration information.

<Location /server-info>
    SetHandler server-info
    Order allow,deny
    # Allow access from server itself
    Allow from 127.0.0.1
    # Additionally, allow access from local workstation
    Allow from 192.168.1.17
</Location>

Selecting the information shown

By default, the server information includes a list of all enabled modules, and for each module, a description of the directives understood by that module, the hooks implemented by that module, and the relevant directives from the current configuration.

Other views of the configuration information are available by appending a query to the server-info request. For example, http://your.host.example.com/server-info?config will show all configuration directives.

?<module-name>

Only information relevant to the named module

?config

Just the configuration directives, not sorted by module

?hooks

Only the list of Hooks each module is attached to

?list

Only a simple list of enabled modules

?server

Only the basic server information

Dumping the configuration on startup

If the config define -DDUMP_CONFIG is set, mod_info will dump the pre-parsed configuration to stdout during server startup. Pre-parsed means that directives like <IfDefine> and <IfModule> are evaluated and environment varialbles are replaced. However it does not represent the final state of the configuration. In particular, it does not represent the merging or overriding that may happen for repeated directives.

This is roughly equivalent to the ?config query.

Known Limitations

mod_info provides its information by reading the parsed configuration, rather than reading the original configuration file. There are a few limitations as a result of the way the parsed configuration tree is created:

• Directives which are executed immediately rather than being stored in the parsed configuration are not listed. These include ServerRoot, LoadModule, and LoadFile.
• Directives which control the configuration file itself, such as Include, <IfModule> and <IfDefine> are not listed, but the included configuration directives are.
• Comments are not listed. (This may be considered a feature.)
• Configuration directives from .htaccess files are not listed (since they do not form part of the permanent server configuration).
• Container directives such as <Directory> are listed normally, but mod_info cannot figure out the line number for the closing </Directory>.
• Directives generated by third party modules such as mod_perl might not be listed.