mod_authz_owner - Apache HTTP Server Version 2.2

Apache Server 2.2

previous page next page

Apache > HTTP Server > Documentation > Version 2.2 > Modules

Apache Module mod_authz_owner

Description:	Authorization based on file ownership
Status:	Extension
Module Identifier:	authz_owner_module
Source File:	mod_authz_owner.c
Compatibility:	Available in Apache 2.1 and later

Summary

This module authorizes access to files by comparing the userid used for HTTP authentication (the web userid) with the file-system owner or group of the requested file. The supplied username and password must be already properly verified by an authentication module, such as mod_auth_basic or mod_auth_digest. mod_authz_owner recognizes two arguments for the Require directive, file-owner and file-group, as follows:

file-owner: The supplied web-username must match the system's name for the owner of the file being requested. That is, if the operating system says the requested file is owned by jones, then the username used to access it through the web must be jones as well.
file-group: The name of the system group that owns the file must be present in a group database, which is provided, for example, by mod_authz_groupfile or mod_authz_dbm, and the web-username must be a member of that group. For example, if the operating system says the requested file is owned by (system) group accounts, the group accounts must appear in the group database and the web-username used in the request must be a member of that group.

Note

If mod_authz_owner is used in order to authorize a resource that is not actually present in the filesystem (i.e. a virtual resource), it will deny the access.

Particularly it will never authorize content negotiated "MultiViews" resources.

Configuration Examples

Require file-owner

Consider a multi-user system running the Apache Web server, with each user having his or her own files in ~/public_html/private. Assuming that there is a single AuthDBMUserFile database that lists all of their web-usernames, and that these usernames match the system's usernames that actually own the files on the server, then the following stanza would allow only the user himself access to his own files. User jones would not be allowed to access files in /home/smith/public_html/private unless they were owned by jones instead of smith.

<Directory /home/*/public_html/private> AuthType Basic AuthName MyPrivateFiles AuthBasicProvider dbm AuthDBMUserFile /usr/local/apache2/etc/.htdbm-all Satisfy All Require file-owner </Directory>

Require file-group

Consider a system similar to the one described above, but with some users that share their project files in ~/public_html/project-foo. The files are owned by the system group foo and there is a single AuthDBMGroupFile database that contains all of the web-usernames and their group membership, i.e. they must be at least member of a group named foo. So if jones and smith are both member of the group foo, then both will be authorized to access the project-foo directories of each other.

<Directory /home/*/public_html/project-foo> AuthType Basic AuthName "Project Foo Files" AuthBasicProvider dbm # combined user/group database AuthDBMUserFile /usr/local/apache2/etc/.htdbm-all AuthDBMGroupFile /usr/local/apache2/etc/.htdbm-all Satisfy All Require file-group </Directory>

AuthzOwnerAuthoritative Directive

Description:	Sets whether authorization will be passed on to lower level modules
Syntax:	`AuthzOwnerAuthoritative On\|Off`
Default:	`AuthzOwnerAuthoritative On`
Context:	directory, .htaccess
Override:	AuthConfig
Status:	Extension
Module:	mod_authz_owner

Setting the AuthzOwnerAuthoritative directive explicitly to Off allows for user authorization to be passed on to lower level modules (as defined in the modules.c files) if:

in the case of file-owner the file-system owner does not match the supplied web-username or could not be determined, or
in the case of file-group the file-system group does not contain the supplied web-username or could not be determined.

Note that setting the value to Off also allows the combination of file-owner and file-group, so access will be allowed if either one or the other (or both) match.

By default, control is not passed on and an authorization failure will result in an "Authentication Required" reply. Not setting it to Off thus keeps the system secure and forces an NCSA compliant behaviour.

previous page start next page