Pass all wiki markup formats through pipelines

Previously, when the wiki page format was anything other than `markdown`
or `asciidoc` the formatted content would be returned though a Gitaly
call. Gitaly in turn would delegate formatting to the gitlab-gollum-lib
gem, which in turn would delegate that to various gems (like RDoc for
`rdoc`) and then apply some very liberal sanitization.

It was too liberal!

This change brings our wiki content formatting in line with how we
format other markdown at GitLab, so we have a SSOT for sanitization.

https://gitlab.com/gitlab-org/gitlab/issues/30540

app/helpers/markup_helper.rb

@@ -133,15 +133,7 @@ module MarkupHelper
       issuable_state_filter_enabled: true
     )
-    html =
-      case wiki_page.format
-      when :markdown
-        markdown_unsafe(text, context)
-      when :asciidoc
-        asciidoc_unsafe(text)
-      else
-        wiki_page.formatted_content.html_safe
-      end
+    html = markup_unsafe(wiki_page.path, text, context)
     prepare_for_rendering(html, context)
   end

app/models/wiki_page.rb

@@ -138,6 +138,12 @@ class WikiPage
     @version ||= @page.version
   end
+  def path
+    return unless persisted?
+
+    @path ||= @page.path
+  end
+
   def versions(options = {})
     return [] unless persisted?

changelogs/unreleased/security-wiki-rdoc-content.yml

+---
+title: Sanitize all wiki markup formats with GitLab sanitization pipelines
+merge_request:
+author:
+type: security

lib/gitlab/other_markup.rb

@@ -10,7 +10,7 @@ module Gitlab
     def self.render(file_name, input, context)
       html = GitHub::Markup.render(file_name, input)
         .force_encoding(input.encoding)
-      context[:pipeline] = :markup
+      context[:pipeline] ||= :markup
       html = Banzai.render(html, context)

spec/helpers/markup_helper_spec.rb

 require 'spec_helper'
 describe MarkupHelper do
-  let!(:project) { create(:project, :repository) }
-
-  let(:user)          { create(:user, username: 'gfm') }
-  let(:commit)        { project.commit }
-  let(:issue)         { create(:issue, project: project) }
-  let(:merge_request) { create(:merge_request, source_project: project, target_project: project) }
-  let(:snippet)       { create(:project_snippet, project: project) }
-
-  before do
-    # Ensure the generated reference links aren't redacted
+  set(:project) { create(:project, :repository) }
+  set(:user) do
+    user = create(:user, username: 'gfm')
     project.add_maintainer(user)
+    user
+  end
+  set(:issue) { create(:issue, project: project) }
+  set(:merge_request) { create(:merge_request, source_project: project, target_project: project) }
+  set(:snippet) { create(:project_snippet, project: project) }
+  let(:commit) { project.commit }
+  before do
     # Helper expects a @project instance variable
     helper.instance_variable_set(:@project, project)
@@ -42,8 +42,8 @@ describe MarkupHelper do
     describe "override default project" do
       let(:actual) { issue.to_reference }
-      let(:second_project) { create(:project, :public) }
-      let(:second_issue) { create(:issue, project: second_project) }
+      set(:second_project) { create(:project, :public) }
+      set(:second_issue) { create(:issue, project: second_project) }
       it 'links to the issue' do
         expected = urls.project_issue_path(second_project, second_issue)
@@ -53,7 +53,7 @@ describe MarkupHelper do
     describe 'uploads' do
       let(:text) { "![ImageTest](/uploads/test.png)" }
-      let(:group) { create(:group) }
+      set(:group) { create(:group) }
       subject { helper.markdown(text) }
@@ -75,7 +75,7 @@ describe MarkupHelper do
       end
       describe "with a group in the context" do
-        let(:project_in_group) { create(:project, group: group) }
+        set(:project_in_group) { create(:project, group: group) }
         before do
           helper.instance_variable_set(:@group, group)
@@ -233,38 +233,48 @@ describe MarkupHelper do
   end
   describe '#render_wiki_content' do
+    let(:wiki) { double('WikiPage', path: "file.#{extension}") }
+    let(:context) do
+      {
+        pipeline: :wiki, project: project, project_wiki: wiki,
+        page_slug: 'nested/page', issuable_state_filter_enabled: true
+      }
+    end
+
     before do
-      @wiki = double('WikiPage')
-      allow(@wiki).to receive(:content).and_return('wiki content')
-      allow(@wiki).to receive(:slug).and_return('nested/page')
-      helper.instance_variable_set(:@project_wiki, @wiki)
+      expect(wiki).to receive(:content).and_return('wiki content')
+      expect(wiki).to receive(:slug).and_return('nested/page')
+      helper.instance_variable_set(:@project_wiki, wiki)
     end
-    it "uses Wiki pipeline for markdown files" do
-      allow(@wiki).to receive(:format).and_return(:markdown)
-      expect(helper).to receive(:markdown_unsafe).with('wiki content',
-        pipeline: :wiki, project: project, project_wiki: @wiki, page_slug: "nested/page",
-        issuable_state_filter_enabled: true)
-      helper.render_wiki_content(@wiki)
+    context 'when file is Markdown' do
+      let(:extension) { 'md' }
+      it 'renders using #markdown_unsafe helper method' do
+        expect(helper).to receive(:markdown_unsafe).with('wiki content', context)
+        helper.render_wiki_content(wiki)
+      end
     end
-    it "uses Asciidoctor for asciidoc files" do
-      allow(@wiki).to receive(:format).and_return(:asciidoc)
-      expect(helper).to receive(:asciidoc_unsafe).with('wiki content')
-      helper.render_wiki_content(@wiki)
+    context 'when file is Asciidoc' do
+      let(:extension) { 'adoc' }
+      it 'renders using Gitlab::Asciidoc' do
+        expect(Gitlab::Asciidoc).to receive(:render)
+        helper.render_wiki_content(wiki)
+      end
     end
-    it "uses the Gollum renderer for all other file types" do
-      allow(@wiki).to receive(:format).and_return(:rdoc)
-      formatted_content_stub = double('formatted_content')
-      expect(formatted_content_stub).to receive(:html_safe)
-      allow(@wiki).to receive(:formatted_content).and_return(formatted_content_stub)
-      helper.render_wiki_content(@wiki)
+    context 'any other format' do
+      let(:extension) { 'foo' }
+      it 'renders all other formats using Gitlab::OtherMarkup' do
+        expect(Gitlab::OtherMarkup).to receive(:render)
+
+        helper.render_wiki_content(wiki)
+      end
     end
   end

spec/models/wiki_page_spec.rb

@@ -439,6 +439,23 @@ describe WikiPage do
     end
   end
+  describe '#path' do
+    let(:path) { 'mypath.md' }
+    let(:wiki_page) { instance_double('Gitlab::Git::WikiPage', path: path).as_null_object }
+
+    it 'returns the path when persisted' do
+      page = described_class.new(wiki, wiki_page, true)
+
+      expect(page.path).to eq(path)
+    end
+
+    it 'returns nil when not persisted' do
+      page = described_class.new(wiki, wiki_page, false)
+
+      expect(page.path).to be_nil
+    end
+  end
+
   describe '#directory' do
     context 'when the page is at the root directory' do
       it 'returns an empty string' do