mod_authz_owner
Authorization based on file ownership
Extension
mod_authz_owner.c
authz_owner_module
Available in Apache 2.1 and later

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.

Require
Satisfy

# 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
Sets whether authorization will be passed on to lower level modules
AuthzOwnerAuthoritative On|Off
AuthzOwnerAuthoritative On
directory
.htaccess
AuthConfig

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.