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The Apache HTTP Server Reference Manual
by Apache Software Foundation
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ISBN 9781906966034
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3.20  Apache Module mod_authz_owner


Authorization based on file ownership



Module Identifier:


Source File:



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:

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.
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" (p. 1423) resources.



See also:

3.20.1  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


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


AuthzOwnerAuthoritative Directive


Sets whether authorization will be passed on to lower level modules


AuthzOwnerAuthoritative On|Off


AuthzOwnerAuthoritative On


directory, .htaccess







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:

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.

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