From 4394e9075189ee6031944491aecd64fb269cdf54 Mon Sep 17 00:00:00 2001
From: Andrew Carpenter <andrew@criticaljuncture.org>
Date: Thu, 28 Jul 2016 16:12:21 -0700
Subject: ensure tag/content_tag escapes " in attribute vals

Many helpers mark content as HTML-safe without escaping double quotes -- including `sanitize`. Regardless of whether or not the attribute values are HTML-escaped, we want to be sure they don't include double quotes, as that can cause XSS issues. For example: `content_tag(:div, "foo", title: sanitize('" onmouseover="alert(1);//'))`

CVE-2016-6316
---
 actionview/lib/action_view/helpers/tag_helper.rb |  2 +-
 actionview/test/template/tag_helper_test.rb      | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

(limited to 'actionview')

diff --git a/actionview/lib/action_view/helpers/tag_helper.rb b/actionview/lib/action_view/helpers/tag_helper.rb
index 030d07845b..7af26edf95 100644
--- a/actionview/lib/action_view/helpers/tag_helper.rb
+++ b/actionview/lib/action_view/helpers/tag_helper.rb
@@ -90,7 +90,7 @@ module ActionView
           else
             value = escape ? ERB::Util.unwrapped_html_escape(value) : value
           end
-          %(#{key}="#{value}")
+          %(#{key}="#{value.gsub(/"/, '&quot;'.freeze)}")
         end
 
         private
diff --git a/actionview/test/template/tag_helper_test.rb b/actionview/test/template/tag_helper_test.rb
index 281fec7291..c7c6649657 100644
--- a/actionview/test/template/tag_helper_test.rb
+++ b/actionview/test/template/tag_helper_test.rb
@@ -274,6 +274,16 @@ class TagHelperTest < ActionView::TestCase
     assert_equal '<p class="song> play&gt;"></p>', tag.p(class: [raw("song>"), "play>"])
   end
 
+  def test_tag_does_not_honor_html_safe_double_quotes_as_attributes
+    assert_dom_equal '<p title="&quot;">content</p>',
+      content_tag('p', "content", title: '"'.html_safe)
+  end
+
+  def test_data_tag_does_not_honor_html_safe_double_quotes_as_attributes
+    assert_dom_equal '<p data-title="&quot;">content</p>',
+      content_tag('p', "content", data: { title: '"'.html_safe })
+  end
+
   def test_skip_invalid_escaped_attributes
     ["&1;", "&#1dfa3;", "& #123;"].each do |escaped|
       assert_equal %(<a href="#{escaped.gsub(/&/, '&amp;')}" />), tag("a", href: escaped)
-- 
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