diff options
| -rw-r--r-- | activesupport/lib/active_support/core_ext/string/output_safety.rb | 24 |
1 files changed, 12 insertions, 12 deletions
diff --git a/activesupport/lib/active_support/core_ext/string/output_safety.rb b/activesupport/lib/active_support/core_ext/string/output_safety.rb index 1b20507c0b..eb02b6a442 100644 --- a/activesupport/lib/active_support/core_ext/string/output_safety.rb +++ b/activesupport/lib/active_support/core_ext/string/output_safety.rb @@ -70,9 +70,20 @@ class ERB # them inside a script tag to avoid XSS vulnerability: # # <script> - # var currentUser = <%= json_escape current_user.to_json %>; + # var currentUser = <%= raw json_escape(current_user.to_json) %>; # </script> # + # It is necessary to +raw+ the result of +json_escape+, so that quotation marks + # don't get converted to <tt>"</tt> entities. +json_escape+ doesn't + # automatically flag the result as HTML safe, since the raw value is unsafe to + # use inside HTML attributes. + # + # If you need to output JSON elsewhere in your HTML, you can just do something + # like this, as any unsafe characters (including quotation marks) will be + # automatically escaped for you: + # + # <div data-user-info="<%= current_user.to_json %>">...</div> + # # WARNING: this helper only works with valid JSON. Using this on non-JSON values # will open up serious XSS vulnerabilities. For example, if you replace the # +current_user.to_json+ in the example above with user input instead, the browser @@ -88,17 +99,6 @@ class ERB # is recommended that you always apply this helper (other libraries, such as the # JSON gem, do not provide this kind of protection by default; also some gems # might override +to_json+ to bypass Active Support's encoder). - # - # The output of this helper method is marked as HTML safe so that you can directly - # include it inside a <tt><script></tt> tag as shown above. - # - # However, it is NOT safe to use the output of this inside an HTML attribute, - # because quotation marks are not escaped. Doing so might break your page's layout. - # If you intend to use this inside an HTML attribute, you should use the - # +html_escape+ helper (or its +h+ alias) instead: - # - # <div data-user-info="<%= h current_user.to_json %>">...</div> - # def json_escape(s) result = s.to_s.gsub(JSON_ESCAPE_REGEXP, JSON_ESCAPE) s.html_safe? ? result.html_safe : result |