Class: Brakeman::CheckRender

Inherits:
BaseCheck
  • Object
show all
Defined in:
lib/brakeman/checks/check_render.rb

Overview

Check calls to render() for dangerous values

Direct Known Subclasses

CheckRenderRCE

Instance Method Summary collapse

Instance Method Details

#check_for_dynamic_path(result) ⇒ Object

Check if path to action or file is determined dynamically



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# File 'lib/brakeman/checks/check_render.rb', line 31

def check_for_dynamic_path result
  view = result[:call][2]

  if sexp? view and original? result
    return if renderable?(view)

    if input = has_immediate_user_input?(view)
      if string_interp? view
        confidence = :medium
      else
        confidence = :high
      end
    else
      return
    end

    return if input.type == :model #skip models
    return if safe_param? input.match

    message = msg("Render path contains ", msg_input(input))

    warn :result => result,
      :warning_type => "Dynamic Render Path",
      :warning_code => :dynamic_render_path,
      :message => message,
      :user_input => input,
      :confidence => confidence,
      :cwe_id => [22]
  end
end

#known_renderable_class?(class_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/brakeman/checks/check_render.rb', line 87

def known_renderable_class? class_name
  klass = tracker.find_class(class_name)
  return false if klass.nil?
  knowns = [
    :"ViewComponent::Base",
    :"ViewComponentContrib::Base",
    :"Phlex::HTML"
  ]
  knowns.any? { |k| klass.ancestor? k }
end

#process_render_result(result) ⇒ Object 



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# File 'lib/brakeman/checks/check_render.rb', line 15

def process_render_result result
  return unless node_type? result[:call], :render

  case result[:call].render_type
  when :partial, :template, :action, :file
    check_for_dynamic_path(result)
  when :inline
  when :js
  when :json
  when :text
  when :update
  when :xml
  end
end

#renderable?(exp) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/brakeman/checks/check_render.rb', line 75

def renderable? exp
  return false unless call?(exp) and constant?(exp.target)

  if exp.method == :with_content
    exp = exp.target
  end

  return false unless constant?(exp.target)
  target_class_name = class_name(exp.target)
  known_renderable_class?(target_class_name) or tracker.find_method(:render_in, target_class_name)
end

#run_check ⇒ Object 



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# File 'lib/brakeman/checks/check_render.rb', line 9

def run_check
  tracker.find_call(:target => nil, :method => :render).each do |result|
    process_render_result result
  end
end

#safe_param?(exp) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/brakeman/checks/check_render.rb', line 62

def safe_param? exp
  if params? exp and call? exp
    method_name = exp.method

    if method_name == :[]
      arg = exp.first_arg
      symbol? arg and [:controller, :action].include? arg.value
    else
      boolean_method? method_name
    end
  end
end