Commit 603fa7c1 authored by Douwe Maan's avatar Douwe Maan Committed by Robert Speicher

Merge branch 'fix-mermaid-xss' into 'security-10-4'

[10.4] Fix stored XSS in code blocks
parent 5e9e5692
...@@ -30,6 +30,9 @@ export default function renderMermaid($els) { ...@@ -30,6 +30,9 @@ export default function renderMermaid($els) {
$els.each((i, el) => { $els.each((i, el) => {
const source = el.textContent; const source = el.textContent;
// Remove any extra spans added by the backend syntax highlighting.
Object.assign(el, { textContent: source });
mermaid.init(undefined, el, (id) => { mermaid.init(undefined, el, (id) => {
const svg = document.getElementById(id); const svg = document.getElementById(id);
......
---
title: Fix stored XSS in code blocks that ignore highlighting
merge_request:
author:
type: security
...@@ -14,23 +14,33 @@ module Banzai ...@@ -14,23 +14,33 @@ module Banzai
end end
def highlight_node(node) def highlight_node(node)
code = node.text
css_classes = 'code highlight js-syntax-highlight' css_classes = 'code highlight js-syntax-highlight'
language = node.attr('lang') lang = node.attr('lang')
retried = false
if use_rouge?(language) if use_rouge?(lang)
lexer = lexer_for(language) lexer = lexer_for(lang)
language = lexer.tag language = lexer.tag
else
lexer = Rouge::Lexers::PlainText.new
language = lang
end
begin
code = Rouge::Formatters::HTMLGitlab.format(lex(lexer, node.text), tag: language)
css_classes << " #{language}" if language
rescue
# Gracefully handle syntax highlighter bugs/errors to ensure users can
# still access an issue/comment/etc. First, retry with the plain text
# filter. If that fails, then just skip this entirely, but that would
# be a pretty bad upstream bug.
return if retried
begin language = nil
code = Rouge::Formatters::HTMLGitlab.format(lex(lexer, code), tag: language) lexer = Rouge::Lexers::PlainText.new
css_classes << " #{language}" retried = true
rescue
# Gracefully handle syntax highlighter bugs/errors to ensure
# users can still access an issue/comment/etc.
language = nil retry
end
end end
highlighted = %(<pre class="#{css_classes}" lang="#{language}" v-pre="true"><code>#{code}</code></pre>) highlighted = %(<pre class="#{css_classes}" lang="#{language}" v-pre="true"><code>#{code}</code></pre>)
......
require 'spec_helper'
describe 'Math rendering', :js do
it 'renders inline and display math correctly' do
description = <<~MATH
This math is inline $`a^2+b^2=c^2`$.
This is on a separate line
```math
a^2+b^2=c^2
```
MATH
project = create(:project, :public)
issue = create(:issue, project: project, description: description)
visit project_issue_path(project, issue)
expect(page).to have_selector('.katex .mord.mathit', text: 'b')
expect(page).to have_selector('.katex-display .mord.mathit', text: 'b')
end
end
require 'spec_helper'
describe 'Mermaid rendering', :js do
it 'renders Mermaid diagrams correctly' do
description = <<~MERMAID
```mermaid
graph TD;
A-->B;
A-->C;
B-->D;
C-->D;
```
MERMAID
project = create(:project, :public)
issue = create(:issue, project: project, description: description)
visit project_issue_path(project, issue)
%w[A B C D].each do |label|
expect(page).to have_selector('svg foreignObject', text: label)
end
end
end
...@@ -3,35 +3,86 @@ require 'spec_helper' ...@@ -3,35 +3,86 @@ require 'spec_helper'
describe Banzai::Filter::SyntaxHighlightFilter do describe Banzai::Filter::SyntaxHighlightFilter do
include FilterSpecHelper include FilterSpecHelper
shared_examples "XSS prevention" do |lang|
it "escapes HTML tags" do
# This is how a script tag inside a code block is presented to this filter
# after Markdown rendering.
result = filter(%{<pre lang="#{lang}"><code>&lt;script&gt;alert(1)&lt;/script&gt;</code></pre>})
expect(result.to_html).not_to include("<script>alert(1)</script>")
expect(result.to_html).to include("alert(1)")
end
end
context "when no language is specified" do context "when no language is specified" do
it "highlights as plaintext" do it "highlights as plaintext" do
result = filter('<pre><code>def fun end</code></pre>') result = filter('<pre><code>def fun end</code></pre>')
expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight plaintext" lang="plaintext" v-pre="true"><code><span id="LC1" class="line" lang="plaintext">def fun end</span></code></pre>') expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight plaintext" lang="plaintext" v-pre="true"><code><span id="LC1" class="line" lang="plaintext">def fun end</span></code></pre>')
end end
include_examples "XSS prevention", ""
end end
context "when a valid language is specified" do context "when a valid language is specified" do
it "highlights as that language" do it "highlights as that language" do
result = filter('<pre><code lang="ruby">def fun end</code></pre>') result = filter('<pre><code lang="ruby">def fun end</code></pre>')
expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight ruby" lang="ruby" v-pre="true"><code><span id="LC1" class="line" lang="ruby"><span class="k">def</span> <span class="nf">fun</span> <span class="k">end</span></span></code></pre>') expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight ruby" lang="ruby" v-pre="true"><code><span id="LC1" class="line" lang="ruby"><span class="k">def</span> <span class="nf">fun</span> <span class="k">end</span></span></code></pre>')
end end
include_examples "XSS prevention", "ruby"
end end
context "when an invalid language is specified" do context "when an invalid language is specified" do
it "highlights as plaintext" do it "highlights as plaintext" do
result = filter('<pre><code lang="gnuplot">This is a test</code></pre>') result = filter('<pre><code lang="gnuplot">This is a test</code></pre>')
expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight plaintext" lang="plaintext" v-pre="true"><code><span id="LC1" class="line" lang="plaintext">This is a test</span></code></pre>') expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight plaintext" lang="plaintext" v-pre="true"><code><span id="LC1" class="line" lang="plaintext">This is a test</span></code></pre>')
end end
include_examples "XSS prevention", "gnuplot"
end end
context "when Rouge formatting fails" do context "languages that should be passed through" do
%w(math mermaid plantuml).each do |lang|
context "when #{lang} is specified" do
it "highlights as plaintext but with the correct language attribute and class" do
result = filter(%{<pre><code lang="#{lang}">This is a test</code></pre>})
expect(result.to_html).to eq(%{<pre class="code highlight js-syntax-highlight #{lang}" lang="#{lang}" v-pre="true"><code><span id="LC1" class="line" lang="#{lang}">This is a test</span></code></pre>})
end
include_examples "XSS prevention", lang
end
end
end
context "when Rouge lexing fails" do
before do before do
allow_any_instance_of(Rouge::Formatter).to receive(:format).and_raise(StandardError) allow_any_instance_of(Rouge::Lexers::Ruby).to receive(:stream_tokens).and_raise(StandardError)
end end
it "highlights as plaintext" do it "highlights as plaintext" do
result = filter('<pre><code lang="ruby">This is a test</code></pre>') result = filter('<pre><code lang="ruby">This is a test</code></pre>')
expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight" lang="" v-pre="true"><code>This is a test</code></pre>')
expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight" lang="" v-pre="true"><code><span id="LC1" class="line" lang="">This is a test</span></code></pre>')
end
include_examples "XSS prevention", "ruby"
end
context "when Rouge lexing fails after a retry" do
before do
allow_any_instance_of(Rouge::Lexers::PlainText).to receive(:stream_tokens).and_raise(StandardError)
end
it "does not add highlighting classes" do
result = filter('<pre><code>This is a test</code></pre>')
expect(result.to_html).to eq('<pre><code>This is a test</code></pre>')
end end
include_examples "XSS prevention", "ruby"
end end
end end
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