The SanitizationFilter was running before the WikiFilter. Since
WikiFilter can modify links, we could see links that _should_ be stopped
by SanatizationFilter being rendered on the page. I (kerrizor) had
previously addressed the bug in: 7bc971915b
However, an additional exploit was discovered after that was merged.
Working through the issue, we couldn't simply shuffle the order of
filters, due to some implicit assumptions about the order of filters, so
instead we've extracted the logic that sanitizes a Nokogiri-generated
Node object, and applied it to the WikiLinkFilter as well.
On moving filters around:
Once we start moving around filters, we get cascading failures; fix one,
another one crops up. Many of the existing filters in the WikiPipeline
chain seem to assume that other filters have already done their work,
and thus operate on a "transform anything that's left" basis;
WikiFilter, for instance, assumes any link it finds in the markdown
should be prepended with the wiki_base_path.. but if it does that, it
also turns `href="@user"` into `href="/path/to/wiki/@user"`, which the
UserReferenceFilter doesn't see as a user reference it needs to
transform into a user profile link. This is true for all the reference
filters in the WikiPipeline.
Excludes a few filters that require more work:
* lib/banzai/filter/image_lazy_load_filter_spec.rb
* lib/banzai/filter/syntax_highlight_filter_spec.rb
* lib/banzai/filter/table_of_contents_filter_spec.rb
Part of #47424
1. An exception would be raised if the filter was called with an invalid
URI. Mainly because we weren't catching the `Addressable` exception.
2. This commit fixes it and adds a spec for the filter.
Original Comments
=================
- Linking behaves as per rules documented here:
https://gitlab.com/gitlab-org/gitlab-ce/blob/16568-document-wiki-linking-behavior/doc/markdown/wiki.md
- All links (to other wiki pages) are rewritten to be at the level of
the app root. We can't use links relative to the current
page ('./foo', 'foo', '../foo'), because they won't work in the
markdown preview, where the current page is suffixed with `/edit`
- Move existing `WikiLinkFilter` specs to `WikiPipeline` spec. It makes
sense to run these tests on the combined output of the pipeline,
rather than a single filter, since we can catch issues with
conflicting filters.
- Add more tests to cover the new linking
@rymai's Review
===============
- Classes nested under `WikiLinkFilter` should declare `WikiLinkFilter`'s
inherit, so nothing changes if the nested class is loaded first.
- Add a blank line after a guard clause
- Use keyword arguments for the `Rewriter` constructor
- Invert a condition - use `if` instead of `unless`
- Inline a `let` in `WikiPipeline` spec - it was only used in a single place
- Change out of date spec names
- Add a comment for every rewrite rule in `Rewriter`
GitLab Bot