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Contents
require 'brakeman/checks/base_check'
class Brakeman::CheckSymbolDoS < Brakeman::BaseCheck
Brakeman::Checks.add_optional self
UNSAFE_METHODS = [:to_sym, :literal_to_sym, :intern, :symbolize_keys, :symbolize_keys!]
@description = "Checks for symbol denial of service"
def run_check
tracker.find_call(:methods => UNSAFE_METHODS, :nested => true).each do |result|
check_unsafe_symbol_creation(result)
end
end
def check_unsafe_symbol_creation result
return if duplicate? result or result[:call].original_line
add_result result
call = result[:call]
if result[:method] == :literal_to_sym
args = call.select { |e| sexp? e }
else
args = [call.target]
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
return if safe_parameter? input.match
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,
:confidence => confidence
end
end
def safe_parameter? input
if call? input
if node_type? input.target, :params
input.method == :[] and
symbol? input.first_arg and
[:controller, :action].include? input.first_arg.value
else
safe_parameter? input.target
end
else
false
end
end
end
Version data entries
11 entries across 11 versions & 2 rubygems