Class: Brakeman::CheckSymbolDoS

Inherits:
BaseCheck show all
Defined in:
lib/brakeman/checks/check_symbol_dos.rb

Constant Summary

Constants inherited from BaseCheck

BaseCheck::CONFIDENCE

Constants included from Util

Util::ALL_PARAMETERS, Util::COOKIES, Util::COOKIES_SEXP, Util::PARAMETERS, Util::PARAMS_SEXP, Util::PATH_PARAMETERS, Util::QUERY_PARAMETERS, Util::REQUEST_ENV, Util::REQUEST_PARAMETERS, Util::REQUEST_PARAMS, Util::SESSION, Util::SESSION_SEXP

Constants inherited from SexpProcessor

SexpProcessor::VERSION

Instance Attribute Summary

Attributes inherited from BaseCheck

#tracker, #warnings

Attributes inherited from SexpProcessor

#context, #env, #expected

Instance Method Summary collapse

Methods inherited from BaseCheck

#add_result, inherited, #initialize, #process_call, #process_cookies, #process_default, #process_if, #process_params, #process_string_interp

Methods included from Util

#array?, #block?, #call?, #camelize, #contains_class?, #context_for, #cookies?, #false?, #file_by_name, #file_for, #hash?, #hash_access, #hash_insert, #hash_iterate, #integer?, #make_call, #node_type?, #number?, #params?, #pluralize, #regexp?, #relative_path, #request_env?, #request_value?, #result?, #set_env_defaults, #sexp?, #string?, #symbol?, #table_to_csv, #true?, #truncate_table, #underscore

Methods included from ProcessorHelper

#class_name, #process_all, #process_all!, #process_call_args, #process_module

Methods inherited from SexpProcessor

#error_handler, #in_context, #initialize, #process, #process_dummy, #scope

Constructor Details

This class inherits a constructor from Brakeman::BaseCheck

Instance Method Details

#check_unsafe_symbol_creation(result) ⇒ Object 



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# File 'lib/brakeman/checks/check_symbol_dos.rb', line 35

def check_unsafe_symbol_creation result
  return if duplicate? result or result[:call].original_line

  add_result result

  call = result[:call]

  if result[:method] == :to_sym
    args = [call.target]
  else
    args = call.select { |e| sexp? e }
  end

  if input = args.map{ |arg| has_immediate_user_input?(arg) }.compact.first
    confidence = CONFIDENCE[:high]
  elsif input = args.map{ |arg| include_user_input?(arg) }.compact.first
    confidence = CONFIDENCE[:med]
  end

  if confidence
    message = "Symbol conversion from unsafe string (#{friendly_type_of input})"

    warn :result => result,
      :warning_type => "Denial of Service",
      :warning_code => :unsafe_symbol_creation,
      :message => message,
      :user_input => input.match,
      :confidence => confidence
  end

end

#run_check ⇒ Object 



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# File 'lib/brakeman/checks/check_symbol_dos.rb', line 8

def run_check
  fix_version = case
    when version_between?('2.0.0', '2.3.17')
      '2.3.18'
    when version_between?('3.1.0', '3.1.11')
      '3.1.12'
    when version_between?('3.2.0', '3.2.12')
      '3.2.13'
    else
      nil
    end

  if fix_version && active_record_models.any?
    warn :warning_type => "Denial of Service",
      :warning_code => :CVE_2013_1854,
      :message => "Rails #{tracker.config[:rails_version]} has a denial of service vulnerability in ActiveRecord: upgrade to #{fix_version} or patch",
      :confidence => CONFIDENCE[:med],
      :file => gemfile_or_environment,
      :link => "https://groups.google.com/d/msg/rubyonrails-security/jgJ4cjjS8FE/BGbHRxnDRTIJ"
  end

  tracker.find_call(:methods => [:to_sym, :literal_to_sym], :nested => true).each do |result|
    check_unsafe_symbol_creation(result)
  end

end