Do not pass unknown encoding names to nokogiri. (#30987)

8 months ago · 2ea9336b68
parent 36592d10aa
commit 2ea9336b68
3 changed files with 35 additions and 1 deletions
--- a/app/lib/link_details_extractor.rb
+++ b/app/lib/link_details_extractor.rb
@ -274,7 +274,7 @@ class LinkDetailsExtractor
  end

  def detect_encoding_and_parse_document
-    [detect_encoding, nil, @html_charset].uniq.each do |encoding|
+    [detect_encoding, nil, header_encoding].uniq.each do |encoding|
      document = Nokogiri::HTML(@html, nil, encoding)
      return document if document.to_s.valid_encoding?
    end
@ -286,6 +286,13 @@ class LinkDetailsExtractor
    guess&.fetch(:confidence, 0).to_i > 60 ? guess&.fetch(:encoding, nil) : nil
  end

+  def header_encoding
+    Encoding.find(@html_charset).name if @html_charset
+  rescue ArgumentError
+    # Encoding from HTTP header is not recognized by ruby
+    nil
+  end
+
  def detector
    @detector ||= CharlockHolmes::EncodingDetector.new.tap do |detector|
      detector.strip_tags = true
--- a/spec/fixtures/requests/alternative_utf8_spelling_in_header.txt
+++ b/spec/fixtures/requests/alternative_utf8_spelling_in_header.txt
@ -0,0 +1,18 @@
+HTTP/1.1 200 OK
+server: nginx
+date: Thu, 13 Jun 2024 14:33:13 GMT
+content-type: text/html; charset=utf8
+content-length: 192
+accept-ranges: bytes
+
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <title>Webserver Configs R Us</title>
+</head>
+<body>
+  <h2>Welcome</h2>
+  <p>Sneaky non-UTF character: á</p>
+</body>
+</html>
--- a/spec/services/fetch_link_card_service_spec.rb
+++ b/spec/services/fetch_link_card_service_spec.rb
@ -32,6 +32,7 @@ RSpec.describe FetchLinkCardService do
    stub_request(:get, 'http://example.com/aergerliche-umlaute').to_return(request_fixture('redirect_with_utf8_url.txt'))
    stub_request(:get, 'http://example.com/page_without_title').to_return(request_fixture('page_without_title.txt'))
    stub_request(:get, 'http://example.com/long_canonical_url').to_return(request_fixture('long_canonical_url.txt'))
+    stub_request(:get, 'http://example.com/alternative_utf8_spelling_in_header').to_return(request_fixture('alternative_utf8_spelling_in_header.txt'))

    Rails.cache.write('oembed_endpoint:example.com', oembed_cache) if oembed_cache

@ -292,6 +293,14 @@ RSpec.describe FetchLinkCardService do
        expect(status.preview_card).to be_nil
      end
    end
+
+    context 'with a URL where the `Content-Type` header uses `utf8` instead of `utf-8`' do
+      let(:status) { Fabricate(:status, text: 'test http://example.com/alternative_utf8_spelling_in_header') }
+
+      it 'does not create a preview card' do
+        expect(status.preview_card.title).to eq 'Webserver Configs R Us'
+      end
+    end
  end

  context 'with a remote status' do