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Contents
require 'brakeman/checks/base_check'
#This check looks for regexes that include user input.
class Brakeman::CheckRegexDoS < Brakeman::BaseCheck
Brakeman::Checks.add self
ESCAPES = {
s(:const, :Regexp) => [
:escape,
:quote
]
}
@description = "Searches regexes including user input"
#Process calls
def run_check
Brakeman.debug "Finding dynamic regexes"
calls = tracker.find_call :method => [:brakeman_regex_interp]
Brakeman.debug "Processing dynamic regexes"
calls.each do |call|
process_result call
end
end
#Warns if regex includes user input
def process_result result
return unless original? result
call = result[:call]
components = call[1..-1]
components.any? do |component|
next unless sexp? component
if match = has_immediate_user_input?(component)
confidence = :high
elsif match = has_immediate_model?(component)
match = Match.new(:model, match)
confidence = :medium
elsif match = include_user_input?(component)
confidence = :weak
end
if match
message = "#{friendly_type_of(match).capitalize} used in regex"
warn :result => result,
:warning_type => "Denial of Service",
:warning_code => :regex_dos,
:message => message,
:confidence => confidence,
:user_input => match
end
end
end
def process_call(exp)
if escape_methods = ESCAPES[exp.target]
if escape_methods.include? exp.method
return exp
end
end
super
end
end
Version data entries
25 entries across 25 versions & 3 rubygems