Restricting read and write access to topics and webs, by Users and groups
TWikiAccessControl allows you restrict access to single topics and entire webs, by individual user and by user Groups, in three areas: view; edit & attach; and rename/move/delete. Access control, combined with TWikiUserAuthentication, lets you easily create and manage an extremely flexible, fine-grained privilege system.
Open, freeform editing is the essence of WikiCulture - what makes TWiki different and often more effective than other collaboration tools. For that reason, it is strongly recommended that decisions to restrict read or write access to a web or a topic are made with care - the more restrictions, the less Wiki in the mix. Experience shows that unrestricted write access works very well because:
As a collaboration guideline:
Access control is based on the familiar concept of Users and Groups. Users are defined by their WikiNames. They can then be organized in unlimited combinations by inclusion in one or more user Groups. For convenience, Groups can also be included in other Groups.
A user can create an account in TWikiRegistration. The following actions are performed:
.htpasswd
if authentication is enabled.
Users can be authenticated using Basic Authentication (htaccess) or SSL (secure server). In either case, TWikiUserAuthentication is required in order to track user identities, and use User and Group access control.
The default visitor name is TWikiGuest. This is the non-authenticated user.
Groups are defined by group topics created in the Main
web, like the TWikiAdminGroup. To create a new group:
Edit
TWikiGroups by entering a new topic with a name that ends in Group
. Example:
SomeGroup
Set GROUP = < list of Users and/or Groups >
Set ALLOWTOPICCHANGE = < list of Users and/or Groups >
Set GROUP = Main.SomeUser, Main.OtherUser, Main.SomeGroup
Set ALLOWTOPICCHANGE = Main.TWikiAdminGroup
You can define who is allowed to make changes to a web or a topic.
Denying editing of a topic also restricts file attachment; both privileges are assigned together.
Set DENYTOPICCHANGE = < list of Users and Groups >
Set ALLOWTOPICCHANGE = < list of Users and Groups >
Set DENYTOPICCHANGE = Main.SomeBadBoy, Main.SomeBadGirl, Main.SomeHackerGroup
Set ALLOWTOPICCHANGE = Main.SomeGoodGuy, Main.SomeGoodGirl, Main.TWikiAdminGroup
Restricting web-level editing blocks creating new topics, changing topics or attaching files.
Set DENYWEBCHANGE = < list of Users and Groups >
Set ALLOWWEBCHANGE = < list of Users and Groups >
The same rules apply as for restricting topics, with these additions:
You can define who is allowed to rename, move or delete a topic, or rename a web.
To allow a user to rename, move or delete a topic, they also need write (editing) permission. They also need write access to change references in referring topics.
Set DENYTOPICRENAME = < list of Users and Groups >
Set ALLOWTOPICRENAME = < list of Users and Groups >
Set DENYTOPICRENAME = Main.SomeBadBoy, Main.SomeBadGirl, Main.SomeHackerGroup
Set ALLOWTOPICRENAME = Main.SomeGoodGuy, Main.SomeGoodGirl, Main.TWikiAdminGroup
You can define restrictions of who is allowed to rename a TWiki web.
Set DENYWEBRENAME = < list of Users and Groups >
Set ALLOWWEBRENAME = < list of Users and Groups >
The same rules apply as for topics, with these additions:
You can define who is allowed to see a web.
Technically it is possible to restrict read access to an individual topic based on DENYTOPICVIEW
/ ALLOWTOPICVIEW
preferences variables, provided that the view script is authenticated. However this setup is not recommended since all content is searchable within a web - a search will turn up view restricted topics.
You can define restrictions of who is allowed to view a TWiki web. You can restrict access to certain webs to selected Users and Groups, by:
The idea is to keep a web hidden by not publishing its URL and by preventing the all webs
search option from accessing obfuscated webs. Do so by enabling the NOSEARCHALL
variable in WebPreferences:
Set NOSEARCHALL = on
This setup can be useful to hide a new web until content its ready for deployment.
Obfuscating webs is insecure, as anyone who knows the URL can access the web.
Use the following setup to authenticate users for topic viewing in all webs and to restrict access to selected webs:
Set DENYWEBVIEW = < list of Users and Groups >
Set ALLOWWEBVIEW = < list of Users and Groups >
DENYWEBVIEW
is evaluated before ALLOWWEBVIEW
. Access is denied if the authenticated person is in the DENYWEBVIEW
list, or not in the ALLOWWEBVIEW
list. Access is granted in case DENYWEBVIEW
and ALLOWWEBVIEW
is not defined.
NOSEARCHALL
variable in its WebPreferences topic:
Set NOSEARCHALL = on
view
to the list of authenticated scripts in the .htaccess
file.
This method only works if the view
script is authenticated, which means that all Users have to login, even for read-only access. (An open guest account, like TWikiGuest, can get around this, allowing anyone to login to a common account with, for example, view-only access for public webs.) TWikiInstallationGuide has more on Basic Authentication, using the .htaccess
file.
Use the following setup to provide unrestricted viewing access to open webs, with authentication only on selected webs:
Set DENYWEBVIEW = < list of Users and Groups >
Set ALLOWWEBVIEW = < list of Users and Groups >
DENYWEBVIEW
is evaluated before ALLOWWEBVIEW
. Access is denied if the authenticated person is in the DENYWEBVIEW
list, or not in the ALLOWWEBVIEW
list. Access is granted in case DENYWEBVIEW
and ALLOWWEBVIEW
is not defined.
NOSEARCHALL
variable in its WebPreferences topic:
Set NOSEARCHALL = on
$doRememberRemoteUser
flag in lib/TWiki.cfg
as described in TWikiUserAuthentication. TWiki will now remember the IP address of an authenticated user.
view
script to viewauth
(or better, create a symbolic link)
viewauth
to the list of authenticated scripts in the .htaccess
file. The view
script should not be listed in the .htaccess
file.
When a user accesses a web where you enabled view restriction, TWiki will redirect from the view
script to the viewauth
script once (this happens only if the user has never edited a topic). Doing so will ask for authentication. The viewauth
script shows the requested topic if the user could log on and if the user is authorized to see that web.
Authenticating webs is not very secure, as there is a way to circumvent the read access restriction. It can be useful in certain situations - for example, to simplify site organization and clutter, by hiding low traffic webs - but is not recommended for securing sensitive content.
To hide access control settings from normal browser viewing, place them in comment markers.
By mistyping a user or group name in the ALLOWTOPICCHANGE setting, it's possible to lock a topic so that no-one can edit it from a browser. To avoid this, you can create Web-based superusers:
$superAdminGroup
variable in lib/TWiki.cfg
to the name of a group of Users who are always allowed to edit/view topics.
$superAdminGroup = "TWikiAdminGroup";
-- PeterThoeny - 04 May 2002
-- MikeMannix? - 12 May 2002
Topic TWikiAccessControl . { Edit | Attach | Ref-By | Printable | Diffs | r1.28 | > | r1.27 | > | r1.26 | More } |
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