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

6 files changed, 74 insertions, 44 deletions

diff --git a/app/helpers/markup_helper.rb b/app/helpers/markup_helper.rb
index d76a0f3a3b8..e2524938e10 100644
--- a/app/helpers/markup_helper.rb
+++ b/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
diff --git a/app/models/wiki_page.rb b/app/models/wiki_page.rb
index cd4c7895587..1b6d8fc47a7 100644
--- a/app/models/wiki_page.rb
+++ b/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?
 
diff --git a/changelogs/unreleased/security-wiki-rdoc-content.yml b/changelogs/unreleased/security-wiki-rdoc-content.yml
new file mode 100644
index 00000000000..f40f1abcd94
--- /dev/null
+++ b/changelogs/unreleased/security-wiki-rdoc-content.yml
@@ -0,0 +1,5 @@
+---
+title: Sanitize all wiki markup formats with GitLab sanitization pipelines
+merge_request:
+author:
+type: security
diff --git a/lib/gitlab/other_markup.rb b/lib/gitlab/other_markup.rb
index bc467486eee..0dd6b8a809c 100644
--- a/lib/gitlab/other_markup.rb
+++ b/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)
 
diff --git a/spec/helpers/markup_helper_spec.rb b/spec/helpers/markup_helper_spec.rb
index f6e1720e113..f0bf547f778 100644
--- a/spec/helpers/markup_helper_spec.rb
+++ b/spec/helpers/markup_helper_spec.rb
@@ -1,18 +1,18 @@
 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)
+    context 'when file is Markdown' do
+      let(:extension) { 'md' }
 
-      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)
+      it 'renders using #markdown_unsafe helper method' do
+        expect(helper).to receive(:markdown_unsafe).with('wiki content', context)
 
-      helper.render_wiki_content(@wiki)
+        helper.render_wiki_content(wiki)
+      end
     end
 
-    it "uses Asciidoctor for asciidoc files" do
-      allow(@wiki).to receive(:format).and_return(:asciidoc)
+    context 'when file is Asciidoc' do
+      let(:extension) { 'adoc' }
 
-      expect(helper).to receive(:asciidoc_unsafe).with('wiki content')
+      it 'renders using Gitlab::Asciidoc' do
+        expect(Gitlab::Asciidoc).to receive(:render)
 
-      helper.render_wiki_content(@wiki)
+        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)
+    context 'any other format' do
+      let(:extension) { 'foo' }
 
-      helper.render_wiki_content(@wiki)
+      it 'renders all other formats using Gitlab::OtherMarkup' do
+        expect(Gitlab::OtherMarkup).to receive(:render)
+
+        helper.render_wiki_content(wiki)
+      end
     end
   end
 
diff --git a/spec/models/wiki_page_spec.rb b/spec/models/wiki_page_spec.rb
index 18c62c917dc..9014276dcf8 100644
--- a/spec/models/wiki_page_spec.rb
+++ b/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