Access Control

Restricting read and write access to topics and webs, by users and groups

Access Control allows you restrict access to single topics and entire webs, by individual user and by user Groups. Access control, combined with UserAuthentication, lets you easily create and manage an extremely flexible, fine-grained privilege system.

An important control consideration

Open, freeform editing is the essence of WikiCulture - what makes Foswiki 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 great care - the more restrictions, the less Wiki in the mix. Experience shows that unrestricted write access works very well because:

  • Peer influence is enough to ensure that only relevant content is posted.
  • Peer editing - the ability for anyone to rearrange all content on a page - keeps topics focused.
  • In Foswiki, content is transparently preserved under revision control:
    • Edits can be undone by the administrator (per default a member of AdminGroup; see #ManagingGroups).
    • Users are encouraged to edit and refactor (condense a long topic), since there's a safety net.
As a collaboration guideline:
  • Create broad-based Groups (for more and varied input), and...
  • Avoid creating view-only Users (if you can read it, you should be able to contribute to it).

Permissions settings of the webs on this Foswiki site

Web Sitemap VIEW CHANGE RENAME
  Listed DENY ALLOW DENY ALLOW DENY ALLOW
Preferences Home Main on            
Preferences Home System on       AdminGroup   AdminGroup
Preferences Home ASLInfra on       PauloSantana?   PauloSantana?
Preferences Home ASLPlanejamento on       PauloSantana?   PauloSantana?
Preferences Home Amadeu on            
Preferences Home Anapolivre on            
Preferences Home ArquivoLivre on            
Preferences Home Arte on            
Preferences Home BSM on            
Preferences Home BahiaSocial              
Preferences Home BeaBa on            
Preferences Home BibliotecaLivre on            
Preferences Home Blogs on            
Preferences Home BrasilDigital on            
Preferences Home BrasilELivre on            
Preferences Home CESL on            
Preferences Home CRC on       FelipeSantos, IsaacFilho, ErikaCeciane   FelipeSantos, IsaacFilho, ErikaCeciane
Preferences Home Ccsa              
Preferences Home CienciaDaComputacaoNaEscola on       AntonioTerceiro?   AntonioTerceiro?
Preferences Home CoberturaWiki              
Preferences Home ConexaoCultura on            
Preferences Home Cooperativas              
Preferences Home CuritibaLivre on           AdminGroup
Preferences Home Curriculo on            
Preferences Home DarvinMarosin on            
Preferences Home DiaD on            
Preferences Home Dinamicoop              
Preferences Home ENSL on            
Preferences Home Economia on            
Preferences Home EconomiaSolidaria on            
Preferences Home EducacaoLivre on            
Preferences Home Ekaaty on            
Preferences Home Emacsbr on            
Preferences Home EstatutoASL on       PauloSantana?   PauloSantana?
Preferences Home FSM2005 on            
Preferences Home Fatos on            
Preferences Home Festival3              
Preferences Home Festival4         FestivalBahiaGroup    
Preferences Home Flisol on            
Preferences Home Fmpb on            
Preferences Home Formatos on            
Preferences Home Foswikibr on            
Preferences Home GNOMEBR on GnomebrDenyGroup          
Preferences Home GNOMEBR.VP on GnomebrDenyGroup          
Preferences Home GTEducacao on            
Preferences Home GTI on       AslGroup   AslGroup
Preferences Home GTSM on            
Preferences Home GTSantaMaria on       GTSantaMariaGroup   GTSantaMariaGroup
Preferences Home GTTemario2004 on            
Preferences Home GTWeb on            
Preferences Home GUSLA on            
Preferences Home Guialivre on            
Preferences Home HDC on            
Preferences Home HnTool on            
Preferences Home Incubus on       IncubusGroup   EricJardim
Preferences Home InkscapeBrasil on            
Preferences Home InkscapeBrasil.ForumComments on            
Preferences Home Jogos              
Preferences Home KSP on       PabloLorenzzoni, FelipeMobus, MarceloTerres, MarcioOliveira   PabloLorenzzoni
Preferences Home KdeBR on       KdebrGroup   KdebrGroup
Preferences Home LGM on            
Preferences Home Landell on       FelipeSantos?, ValessioBrito?, LucasSantos?, FabricioSolagna?, LuisFelipe?   FelipeSantos?, ValessioBrito?, LucasSantos?, FabricioSolagna?, LuisFelipe?
Preferences Home LinuxStokDoc              
Preferences Home Livros on            
Preferences Home MHHOB on            
Preferences Home Mentores on            
Preferences Home MinuanoDigital on            
Preferences Home MoradiaECidadania on            
Preferences Home OID on           RodrigoTroian?
Preferences Home OLPC on            
Preferences Home OOPTQ              
Preferences Home OlhosDagua on            
Preferences Home Olimpo on            
Preferences Home Orca on           AdminGroup
Preferences Home PCLivre on            
Preferences Home PSLAL on            
Preferences Home PSLBA on            
Preferences Home PSLBancarios on            
Preferences Home PSLBrasil on            
Preferences Home PSLGO on            
Preferences Home PSLMA on            
Preferences Home PSLMG on            
Preferences Home PSLMIP on            
Preferences Home PSLMT on            
Preferences Home PSLMulheres on            
Preferences Home PSLPI on            
Preferences Home Papers on            
Preferences Home PentahoBrasil on            
Preferences Home Pessoas on            
Preferences Home Portal on            
Preferences Home Prefeituras on       PesquisaSoftexGroup    
Preferences Home ProjSERS on       RodrigoTroian?   RodrigoTroian?
Preferences Home PubFisl10 on            
Preferences Home PubFisl11 on       PabloLorenzzoni, FelipeMobus   PabloLorenzzoni
Preferences Home PubFisl12 on       PabloLorenzzoni?   PabloLorenzzoni?
Preferences Home PubFisl7              
Preferences Home PubFisl8 on            
Preferences Home PubFisl9 on            
Preferences Home QuilomboDoSopapo on            
Preferences Home R2D2 on            
Preferences Home RadioSL on            
Preferences Home RaulHackerClub on            
Preferences Home RedeMesh on            
Preferences Home RedePopular              
Preferences Home RobotWars on            
Preferences Home RoboticaLivre on       AntonioTerceiro?   AntonioTerceiro?
Preferences Home SLCampusParty on            
Preferences Home SLRJ on            
Preferences Home Sandbox on            
Preferences Home Saudelivre on            
Preferences Home Scribus on            
Preferences Home Sementes on            
Preferences Home Shakya on            
Preferences Home SoLiSC on       SoLiSCGroup    
Preferences Home SoftwareLivreIrece on            
Preferences Home SoftwareLivreVS on            
Preferences Home SuporteLivre              
Preferences Home TV on            
Preferences Home TWikiBar on            
Preferences Home TWikiPtbr on           TWikiAdminGroup
Preferences Home Telecentros on            
Preferences Home TeseSA on       TeseSAGroup    
Preferences Home TextoLivre on            
Preferences Home UNELivre on            
Preferences Home UNIMIX              
Preferences Home VilaTorres              
Preferences Home WSL on           AntonioTerceiro?
Preferences Home WSL.WSL2012 on           AntonioTerceiro?
Preferences Home WSL.WSL2013 on           AntonioTerceiro?
Preferences Home WTRD2004 on            
Preferences Home WebNordeste              

Please Note:

  • A blank in the the above table may mean either the corresponding control is absent or commented out or that it has been set to a null value. The two conditions have dramatically different and possibly opposed semantics.
  • WikiGuest is the guest account - used by unauthenticated users.
  • The web must not deny view to WikiGuest; otherwise, people will not be able to register.

HELP Above table comes from SitePermissions

Authentication vs. Access Control

Authentication: Identifies who a user is based on a login procedure. See UserAuthentication.

Access control: Restrict access to content based on users and groups once a user is identified.

Users and groups

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.

Managing Users

A user can create an account in UserRegistration. The following actions are performed:

  • WikiName and encrypted password are recorded using the password manager if authentication is enabled.
  • A confirmation e-mail is sent to the user.
  • A user home page with the WikiName of the user is created in the Main web.
  • The user is added to the WikiUsers topic.

The default visitor name is WikiGuest. This is the non-authenticated user.

Managing Groups

The following describes the standard Foswiki support for groups. Your local Foswiki may have an alternate group mapping manager installed. Check with your Wiki administrator if you are in doubt.

Groups are defined by group topics located in the Main web. To create a new group, visit WikiGroups and enter the name of the new group ending in Group into the "new group" form field. This will create a new group topic with two important settings:

  • Set GROUP = < list of users and/or groups >
  • Set ALLOWTOPICCHANGE = < list of users and/or groups >

The GROUP setting is a comma-separated list of users and/or other groups. Example:

  • Set GROUP = Main.SomeUser, Main.OtherUser, Main.SomeGroup

The ALLOWTOPICCHANGE setting defines who is allowed to change the group topic; it is a comma delimited list of users and groups. You typically want to restrict that to the members of the group itself, so it should contain the name of the topic. This prevents users not in the group from editing the topic to give themselves or others access. For example, for the KasabianGroup topic write:

  • Set ALLOWTOPICCHANGE = Main.KasabianGroup

ALERT! Foswiki has strict formatting rules. Make sure you have three spaces, an asterisk, and an extra space in front of any access control rule.

The Super Admin Group

A number of Foswiki functions (for example, renaming webs) are only available to administrators. Administrators are simply users who belong to the SuperAdminGroup. This is a standard user group, the name of which is defined by {SuperAdminGroup} setting in configure. The default name of this group is the AdminGroup. The system administrator may have chosen a different name for this group if your local Foswiki uses an alternate group mapping manager but for simplicity we will use the default name AdminGroup in the rest of this topic.

You can create new administrators simply by adding them to the AdminGroup topic. For example,

  • Set GROUP = Main.ElizabethWindsor, Main.TonyBlair
A member of the Super Admin Group has unrestricted access throughout the Foswiki, so only trusted staff should be added to this group.

Restricting Access

You can define who is allowed to read or write to a web or a topic. Note that some plugins may not respect access permissions.

  • Restricting VIEW blocks viewing and searching of content. When you restric VIEW to a topic or web, this also restricts INCLUDE and Formatted SEARCH from showing the content of the topics.
  • Restricting CHANGE blocks creating new topics, changing topics or attaching files.
  • Restricting RENAME prevents renaming of topics within a web.

ALERT! There is an important distinction between CHANGE access and RENAME access. A user can CHANGE a topic, but thanks to version control their changes cannot be lost (the history of the topic before the change is recorded). However if a topic or web is renamed, that history may be lost. Typically a site will only give RENAME access to administrators and content owners.

Controlling access to a Web

You can define restrictions on who is allowed to view a Wiki-SL web. You can restrict access to certain webs to selected users and groups, by:

  • authenticating all webs and restricting selected webs: Topic access in all webs is authenticated, and selected webs have restricted access.
  • authenticating and restricting selected webs only: Provide unrestricted viewing access to open webs, with authentication and restriction only on selected webs.

  • You can define these settings in the WebPreferences topic, preferable towards the end of the topic:
    • Set DENYWEBVIEW = < comma-delimited list of users and groups >
    • Set ALLOWWEBVIEW = < comma-delimited list of users and groups >
    • Set DENYWEBCHANGE = < comma-delimited list of users and groups >
    • Set ALLOWWEBCHANGE = < comma-delimited list of users and groups >
    • Set DENYWEBRENAME = < comma-delimited list of users and groups >
    • Set ALLOWWEBRENAME = < comma-delimited list of users and groups >

If your site allows hierarchical webs, then access to sub-webs is determined from the access controls of the parent web, plus the access controls in the sub-web. So, if the parent web has ALLOWWEBVIEW set, this will also apply to the subweb. Also note that you will need to ensure that the parent web's FINALPREFERENCES does not include the access control settings listed above. Otherwise you will not be able override the parent web's access control settings in sub-webs.

Creation and renaming of sub-webs is controlled by the WEBCHANGE setting on the parent web (or ROOTCHANGE for root webs). Renaming is additionally restricted by the setting of WEBRENAME in the web itself.

Controlling access to a topic

  • You can define these settings in any topic, preferable towards the end of the topic:
    • Set DENYTOPICVIEW = < comma-delimited list of users and groups >
    • Set ALLOWTOPICVIEW = < comma-delimited list of users and groups >
    • Set DENYTOPICCHANGE = < comma-delimited list of users and groups >
    • Set ALLOWTOPICCHANGE = < comma-delimited list of users and groups >
    • Set DENYTOPICRENAME = < comma-delimited list of users and groups >
    • Set ALLOWTOPICRENAME = < comma-delimited list of users and groups >

ALERT! Caution! Settings are always taken from the latest (current) revision of a topic. If older revisions of a topic had more restrictive access controls, they will not be used when accessing the older revision.

Remember when opening up access to specific topics within a restricted web that other topics in the web - for example, the WebLeftBar? - may also be accessed when viewing the topics. The message you get when you are denied access should tell you what topic you were not permitted to access.

Be careful with empty values for any of these.

  • Set ALLOWTOPICVIEW =
    This means the same as not setting it at all. (This was documented wrong in versions 4.0.X, 4.1.0 and 4.1.1)

  • Set DENYTOPICVIEW =
    This means do not deny anyone the right to view this topic. If DENYTOPICVIEW is set to an empty value anyone has access even if ALLOWTOPICVIEW or ALLOWWEBVIEW is defined. This allows you to have very restrictive default access rights to an entire web and still allow individual topics to have more open access.

The same rules apply to ALLOWTOPICCHANGE/DENYTOPICCHANGE and APPLYTOPICRENAME/DENYTOPICRENAME. Setting ALLOWTOPICCHANGE or ALLOWTOPICRENAME to en empty value means the same as not defining it. Setting DENYTOPICCHANGE or DENYTOPICRENAME to an empty value means that anyone can edit or rename the topic.

ALERT! If the same setting is defined multiple times the last one overrides the previous. They are not OR'ed together.

ALERT! The setting to an empty has caused confusion and great debate and it has been decided that the empty setting syntax will be replaced by something which is easier to understand in a later version of Foswiki. A method to upgrade will be provided. Please read the release notes carefully when you upgrade.

See "How Foswiki evaluates ALLOW/DENY settings" below for more on how ALLOW and DENY interacts.

Controlling access to attachments

Attachments are referred to directly, and are not normally indirected via Foswiki scripts. This means that the above instructions for access control will not apply to attachments. It is possible that someone may inadvertently publicise a URL that they expected to be access-controlled.

The easiest way to apply the same access control rules for attachments as apply to topics is to use the Apache mod_rewrite module, and configure your webserver to redirect accesses to attachments to the Foswiki viewfile script. For example,

    ScriptAlias /foswiki/bin/ /filesystem/path/to/bin/
    Alias /foswiki/pub/       /filesystem/path/to/pub/

    RewriteEngine on
    RewriteCond %{REQUEST_URI} !^/+foswiki/+pub/+System/+.+
    RewriteRule ^/+foswiki/+pub/+([^/]+)((/+([^/]+))+)/+(.+) /foswiki/bin/viewfile/$1/$2?filename=$5 [L,PT]

That way all the controls that apply to the topic also apply to attachments to the topic. Other types of webserver have similar support.

HELP Images embedded in topics will load much slower since each image will be delivered by the viewfile script.

Controlling who can manage top-level webs

Top level webs are a special case, because they don't have a parent web with a WebPreferences. So there has to be a special control just for the root level.

  • You can define these settings in the DefaultPreferences? topic, preferable towards the end of the topic:
    • Set DENYROOTCHANGE = < comma-delimited list of users and groups >
    • Set ALLOWROOTCHANGE = < comma-delimited list of users and groups >
Note that you do not require ROOTCHANGE access to rename an existing top-level web. You just need WEBCHANGE in the web itself.

How Foswiki evaluates ALLOW/DENY settings

When deciding whether to grant access, Foswiki evaluates the following rules in order (read from the top of the list; if the logic arrives at PERMITTED or DENIED that applies immediately and no more rules are applied). You need to read the rules bearing in mind that VIEW, CHANGE and RENAME access may be granted/denied separately.

ALERT! Settings are only read from the most current (latest) revision of a topic. Settings from older revisions are never used, even when viewing an older revision with the rdiff script

  1. If the user is an administrator
    • access is PERMITTED.
  2. If DENYTOPIC is set to a list of wikinames
    • people in the list will be DENIED.
  3. If DENYTOPIC is set to empty ( i.e. Set DENYTOPIC = )
    • access is PERMITTED i.e no-one is denied access to this topic.
      ALERT! Attention: Use this with caution. This is deprecated and will likely change in the next release.
  4. If ALLOWTOPIC is set
    1. people in the list are PERMITTED
    2. everyone else is DENIED
  5. If DENYWEB is set to a list of wikinames
    • people in the list are DENIED access
  6. If ALLOWWEB is set to a list of wikinames
    • people in the list will be PERMITTED
    • everyone else will be DENIED
  7. If you got this far, access is PERMITTED

Access control and INCLUDE

ALLOWTOPICVIEW and ALLOWTOPICCHANGE only applies to the topic in which the settings are defined. If a topic A includes another topic B, topic A does not inherit the access rights of the included topic B.

Examples: Topic A includes topic B

  • If the included topic B has ALLOWTOPICCHANGE set to block editing for a user, it does not prevent editing the including topic A.
  • If the included topic B has ALLOWTOPICVIEW set to block view for a user, the user can still view topic A but he cannot see the included topic B. He will see a message No permission to view B

Access control quick recipes

Obfuscating webs

Another way of hiding webs is to keep them hidden by not publishing the URL and by preventing the all webs search option from accessing obfuscated webs. Do so by setting the NOSEARCHALL setting in WebPreferences:

  • Set NOSEARCHALL = on

TIP Setting NOSEARCHALL to any value other than the empty string will hide a web. Setting NOSEARCHALL = off will have the same effect as setting it to on

This setup can be useful to hide a new web until content its ready for deployment, or to hide view access restricted webs.

ALERT! Obfuscating a web without view access control is very insecure, as anyone who knows the URL can access the web.

Restrict Access to a whole Foswiki site

For a firewalled Foswiki, e.g. an intranet wiki or extranet wiki, you want to allow only invited people to access your Foswiki. In this case, enable user authentication with ApacheLogin and lock down access to the whole bin and pub directories to all but valid users. In the Apache .htaccess file or the appropriate .conf file, replace the <FilesMatch "(attach|edit|... section with this:

<FilesMatch ".*">
       require valid-user
</FilesMatch>

If needed, you can further restrict access to selected webs with ALLOWWEBVIEW and other access control settings.

HELP With this configuration, someone with access to the site needs to register new users.

Authenticate all webs and restrict selected webs

Use the following setup to authenticate users for topic viewing in all webs and to restrict access to selected webs. Requires UserAuthentication to be enabled.

  1. The simple way is to add this to WebPreferences in all webs.
    • Set DENYWEBVIEW = WikiGuest?
  2. Restrict view access to selected users and groups. Set one or both of these settings in its WebPreferences topic:
    • Set ALLOWWEBVIEW = < list of users and groups >
    • Note: 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 if DENYWEBVIEW and ALLOWWEBVIEW are not defined.

In rare cases it may be required to authenticate the view script. This can in some cases have a dramatic performance hit because the webserver must re-authenticate for every page view.

  1. Set require valid-user on your view script in .htaccess or the appropriate Apache .conf file. This looks like: FilesMatch "(attach|edit|manage|rename|save|view|upload|mail|logon|.*auth).*" (normally view is not in that list).

Authenticate and restrict selected webs only

Use the following setup to provide unrestricted viewing access to open webs, with authentication only on selected webs. Requires UserAuthentication to be enabled.

  1. Restrict view access to selected users and groups. Set one or both of these settings in its WebPreferences topic:
    • Set DENYWEBVIEW = < list of users and groups >
    • Set ALLOWWEBVIEW = < list of users and groups >
    • Note: 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 if DENYWEBVIEW and ALLOWWEBVIEW are not defined.

Hide control settings

TIP To hide access control settings from normal browser viewing, you can put them into the topic preference settings by clicking the link Edit topic preference settings under More topic actions menu. Preferences set in this manner are not visible in the topic text, but take effect nevertheless. Access control settings added as topic preference settings are stored in the topic meta data and they override settings defined in the topic text.

Alternatively, place them in HTML comment markers, but this exposes the access setting during ordinary editing.

<!--
   * Set DENYTOPICCHANGE = Main.SomeGroup
-->


Related Topics: AdminDocumentationCategory, UserAuthentication
Topic revision: r1 - 12 Sep 2009 - 02:10:01 - ProjectContributor

 
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