Class: RuboCop::Cop::Rails::OutputSafety

Inherits:
RuboCop::Cop show all
Defined in:
lib/rubocop/cop/rails/output_safety.rb

Overview

This cop checks for the use of output safety calls like ‘html_safe`, `raw`, and `safe_concat`. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use `safe_join` to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Examples:

user_content = "<b>hi</b>"

# bad
"<p>#{user_content}</p>".html_safe
# => ActiveSupport::SafeBuffer "<p><b>hi</b></p>"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "<p>&lt;b&gt;hi&lt;/b&gt;</p>"

# bad
out = ""
out << "<li>#{user_content}</li>"
out << "<li>#{user_content}</li>"
out.html_safe
# => ActiveSupport::SafeBuffer "<li><b>hi</b></li><li><b>hi</b></li>"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "<li>&lt;b&gt;hi&lt;/b&gt;</li><li>&lt;b&gt;hi&lt;/b&gt;</li>"

# bad
out = "<h1>trusted content</h1>".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "<h1>trusted_content</h1><b>hi</b>"

# good
out = "<h1>trusted content</h1>".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "<h1>trusted_content</h1>&lt;b&gt;hi&lt;/b&gt;"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted content<b>hi</b>"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content&lt;b&gt;hi&lt;/b&gt;

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "<b>hi</b> <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "&lt;b&gt;hi&lt;/b&gt; <span>&lt;b&gt;hi&lt;/b&gt;</span>"

Constant Summary collapse

MSG = 
'Tagging a string as html safe may be a security risk.'

Instance Method Summary collapse

Instance Method Details

#on_send(node) ⇒ Object Also known as: on_csend 



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# File 'lib/rubocop/cop/rails/output_safety.rb', line 68

def on_send(node)
  return if non_interpolated_string?(node)

  return unless looks_like_rails_html_safe?(node) ||
                looks_like_rails_raw?(node) ||
                looks_like_rails_safe_concat?(node)

  add_offense(node, location: :selector)
end