[[!toc levels=3]]

# Zoned ikiwiki

## The idea

The idea behind this would be to have one ikiwiki behave as a dynamic private wiki in a specified area
and a more static publiczone wiki. Actually private wiki page can be addressed via a *pagespec*. 

What is ready /can be done:

* We already can more or less do this for example with [[httpauth|/plugins/httpauth/]], *.htaccess* files and a proper *httpauth_pagespec*
yet at the cost of maintaining two different user/pass logbase (native ikiwiki signin)
* Furthermore we can [[lockedit|plugins/lockedit/]] some pagespecs, ie in the public zone.

## Obstacles

A number of ikiwiki features aren't (yet) designed with zoning in mind,
and it will take some effort both to identify them all, and to think out how they
could be addressed. This section invites brainstorming of both kinds.
This might eventually merit a separate page [[Zoned ikiwiki obstacles]]
but I'll begin it here.

Note that not all of these issues will be problems for all **zoned ikiwiki use cases**.

### Backlinks

What is problematic is when you link a public page in a private page : 
a backlink will be generated from the public page to the private page.

As noted in [[per_page_ACLs]] in the end users through backlink 
navigation will frequently hit HTTP/401 deterring browsing as well as for the admin at false-positive logwatching.

One can radically [[disable backlinks feature|todo/allow_disabling_backlinks]] but then no more neat backlink navigation that
is really good to have in both area.

Another way of just preventing this backlink leak in that case would be sufficient via i.e a *privatebacklinks* config and
a patch like this one [[!toggle id="backlinkpatch" text="(show)"]].

[[!toggleable id="backlinkpatch" text="""
Comments are welcome.

[[mathdesc]]


<pre>
diff --git a/IkiWiki.pm b/IkiWiki.pm
--- a/IkiWiki.pm
+++ b/IkiWiki.pm
@@ -294,6 +294,14 @@ sub getsetup () {
                safe => 1,
                rebuild => 1,
        },
+       privatebacklinks => {
+               type => "pagespec",
+               example => "",
+               description => "PageSpec controlling which backlinks are private (ie users/*)",
+               link => "ikiwiki/PageSpec",
+               safe => 1,
+               rebuild => 1,
+       },
        hardlink => {
                type => "boolean",
                default => 0,
diff --git a/IkiWiki/Render.pm b/IkiWiki/Render.pm
--- a/IkiWiki/Render.pm
+++ b/IkiWiki/Render.pm
@@ -52,7 +52,8 @@ sub backlinks ($) {
                        $p_trimmed=~s/^\Q$dir\E// &&
                        $page_trimmed=~s/^\Q$dir\E//;
                               
-               push @links, { url => $href, page => pagetitle($p_trimmed) };
+               push @links, { url => $href, page => pagetitle($p_trimmed) }
+               unless defined $config{privatebacklinks} && length $config{privatebacklinks} && pagespec_match($p, $config{privatebacklinks}) && !pagespec_match($page, $config{privatebacklinks}) ;
        }
        return @links;
 }

</pre>
"""]]

In use cases where the main concern about backlinks is only the bad user experience when links are
shown that lead to access denial when clicked, a workable
solution could be to make the backlinks `div` invisible in `local.css`.

### recentchanges page

An accessible `recentchanges` page can include links to changes to pages
that should not be accessible. Even if the links cannot be followed, the
existence of the pages and their edit history are leaked. If rcs integration
is configured, those links on the `recentchanges` page can leak complete contents
through the **rcs browser**.

It can be helpful to generate separate `recentchanges` pages for different zones.
The [[plugins/recentchanges]] plugin already allows this--a `recentchanges` page
can be created anywhere, just by using the `recentchanges` directive
with the right [[ikiwiki/PageSpec]] for the zone it should cover--except that it cannot yet
be configured to generate a different `recentchanges` link destination into pages
in different zones. So, it would be helpful if its configuration could allow multiple
`recentchangespage` values, paired with `PageSpec`s for the pages on which they
should be used.

### rcs browser

If the repository browser is accessible, potentially all content can be exposed.
Even if links to the repository browser are not generated into public wiki pages,
if a user can obtain or guess the repository browser URL and construct arbitrary
requests, information can be revealed.

Solutions could involve authnz features of the revision control systems themselves
and their associated repository browsers; for example, `svn` supposedly has such
features, and recent versions of `viewvc` supposedly honor them. But such features
may not be available for every rcs, and where they are available, they'll have to
be configured separately and differently from ikiwiki itself. They might not support
the same auth methods (e.g. OpenID) being used by the wiki itself.

Another approach would be for ikiwiki's own rcs plugin to generate a CGI wrapper
that invokes the repository browser CGI (which itself would _not_ be made
executable via `http` request). The `historyurl` and `diffurl` would then refer
to this wrapper. (In fact, they would not have to be specified in the config file,
as the plugin would know where it generated them. Instead, what would need to be
specified would be the filesystem path for the rcs browser being wrapped). The
wrapper could dissect the request parameters, identify the pages being accessed,
and subject them to the same accessibility tests used for the wiki. The rcs browser
itself needs to be configured to use the wrapper URL in all its generated links,

This might not be very hard to do with `gitweb` as it is already implemented in Perl.
The wrapper could probably import it and use its already-supplied routines to parse
the request into the affected file names, and probably complete the whole request
without a second `exec`. Other rcs backends might or might not be as easy.

### Information leaks allowed by edit access

> Have you considered all the ways that anyone with edit access to the
> public wiki could expose information from the public wiki? For example,
> you could inline all the private pages into a public page. --[[Joey]]

Many ikiwiki features could give information exposure opportunities to someone
with edit access. The list here is surely incomplete, and would take a purposeful
review of the code and plugins (including third-party plugins) to complete.

* Directives that can inline information from other pages
    * [[ikiwiki/directive/inline]] *the most obvious one*
    * [[ikiwiki/directive/map]]
    * [[ikiwiki/directive/brokenlinks]] ?
    * [[ikiwiki/directive/orphans]] ?
    * [[ikiwiki/directive/linkmap]] ?
    * _others_?
* Not to forget `contrib` plugins
    * [[plugins/contrib/report]] ?
    * _others_?