diff options
Diffstat (limited to 'actionpack/lib/action_controller/metal/request_forgery_protection.rb')
| -rw-r--r-- | actionpack/lib/action_controller/metal/request_forgery_protection.rb | 135 |
1 files changed, 99 insertions, 36 deletions
diff --git a/actionpack/lib/action_controller/metal/request_forgery_protection.rb b/actionpack/lib/action_controller/metal/request_forgery_protection.rb index a7bd3622ee..91b3403ad5 100644 --- a/actionpack/lib/action_controller/metal/request_forgery_protection.rb +++ b/actionpack/lib/action_controller/metal/request_forgery_protection.rb @@ -20,7 +20,7 @@ module ActionController #:nodoc: # Since HTML and JavaScript requests are typically made from the browser, we # need to ensure to verify request authenticity for the web browser. We can # use session-oriented authentication for these types of requests, by using - # the `protect_form_forgery` method in our controllers. + # the `protect_from_forgery` method in our controllers. # # GET requests are not protected since they don't have side effects like writing # to the database and don't leak sensitive information. JavaScript requests are @@ -77,6 +77,14 @@ module ActionController #:nodoc: config_accessor :log_warning_on_csrf_failure self.log_warning_on_csrf_failure = true + # Controls whether the Origin header is checked in addition to the CSRF token. + config_accessor :forgery_protection_origin_check + self.forgery_protection_origin_check = false + + # Controls whether form-action/method specific CSRF tokens are used. + config_accessor :per_form_csrf_tokens + self.per_form_csrf_tokens = false + helper_method :form_authenticity_token helper_method :protect_against_forgery? end @@ -90,19 +98,21 @@ module ActionController #:nodoc: # # class FooController < ApplicationController # protect_from_forgery except: :index + # end # # You can disable forgery protection on controller by skipping the verification before_action: + # # skip_before_action :verify_authenticity_token # # Valid Options: # - # * <tt>:only/:except</tt> - Only apply forgery protection to a subset of actions. Like <tt>only: [ :create, :create_all ]</tt>. + # * <tt>:only/:except</tt> - Only apply forgery protection to a subset of actions. For example <tt>only: [ :create, :create_all ]</tt>. # * <tt>:if/:unless</tt> - Turn off the forgery protection entirely depending on the passed Proc or method reference. - # * <tt>:prepend</tt> - By default, the verification of the authentication token is added to the front of the - # callback chain. If you need to make the verification depend on other callbacks, like authentication methods - # (say cookies vs OAuth), this might not work for you. Pass <tt>prepend: false</tt> to just add the - # verification callback in the position of the protect_from_forgery call. This means any callbacks added - # before are run first. + # * <tt>:prepend</tt> - By default, the verification of the authentication token will be added at the position of the + # protect_from_forgery call in your application. This means any callbacks added before are run first. This is useful + # when you want your forgery protection to depend on other callbacks, like authentication methods (Oauth vs Cookie auth). + # + # If you need to add verification to the beginning of the callback chain, use <tt>prepend: true</tt>. # * <tt>:with</tt> - Set the method to handle unverified request. # # Valid unverified request handling methods are: @@ -110,7 +120,7 @@ module ActionController #:nodoc: # * <tt>:reset_session</tt> - Resets the session. # * <tt>:null_session</tt> - Provides an empty session during request but doesn't reset it completely. Used as default if <tt>:with</tt> option is not specified. def protect_from_forgery(options = {}) - options = options.reverse_merge(prepend: true) + options = options.reverse_merge(prepend: false) self.forgery_protection_strategy = protection_method_class(options[:with] || :null_session) self.request_forgery_protection_token ||= :authenticity_token @@ -136,17 +146,17 @@ module ActionController #:nodoc: # This is the method that defines the application behavior when a request is found to be unverified. def handle_unverified_request request = @controller.request - request.session = NullSessionHash.new(request.env) - request.env['action_dispatch.request.flash_hash'] = nil - request.env['rack.session.options'] = { skip: true } - request.env['action_dispatch.cookies'] = NullCookieJar.build(request) + request.session = NullSessionHash.new(request) + request.flash = nil + request.session_options = { skip: true } + request.cookie_jar = NullCookieJar.build(request, {}) end protected class NullSessionHash < Rack::Session::Abstract::SessionHash #:nodoc: - def initialize(env) - super(nil, env) + def initialize(req) + super(nil, req) @data = {} @loaded = true end @@ -160,14 +170,6 @@ module ActionController #:nodoc: end class NullCookieJar < ActionDispatch::Cookies::CookieJar #:nodoc: - def self.build(request) - key_generator = request.env[ActionDispatch::Cookies::GENERATOR_KEY] - host = request.host - secure = request.ssl? - - new(key_generator, host, secure, options_for_env({})) - end - def write(*) # nothing end @@ -258,26 +260,46 @@ module ActionController #:nodoc: # Returns true or false if a request is verified. Checks: # - # * is it a GET or HEAD request? Gets should be safe and idempotent + # * Is it a GET or HEAD request? Gets should be safe and idempotent # * Does the form_authenticity_token match the given token value from the params? # * Does the X-CSRF-Token header match the form_authenticity_token def verified_request? !protect_against_forgery? || request.get? || request.head? || - valid_authenticity_token?(session, form_authenticity_param) || - valid_authenticity_token?(session, request.headers['X-CSRF-Token']) + (valid_request_origin? && any_authenticity_token_valid?) + end + + # Checks if any of the authenticity tokens from the request are valid. + def any_authenticity_token_valid? + request_authenticity_tokens.any? do |token| + valid_authenticity_token?(session, token) + end + end + + # Possible authenticity tokens sent in the request. + def request_authenticity_tokens + [form_authenticity_param, request.x_csrf_token] end # Sets the token value for the current session. - def form_authenticity_token - masked_authenticity_token(session) + def form_authenticity_token(form_options: {}) + masked_authenticity_token(session, form_options: form_options) end # Creates a masked version of the authenticity token that varies # on each request. The masking is used to mitigate SSL attacks # like BREACH. - def masked_authenticity_token(session) + def masked_authenticity_token(session, form_options: {}) + action, method = form_options.values_at(:action, :method) + + raw_token = if per_form_csrf_tokens && action && method + action_path = normalize_action_path(action) + per_form_csrf_token(session, action_path, method) + else + real_csrf_token(session) + end + one_time_pad = SecureRandom.random_bytes(AUTHENTICITY_TOKEN_LENGTH) - encrypted_csrf_token = xor_byte_strings(one_time_pad, real_csrf_token(session)) + encrypted_csrf_token = xor_byte_strings(one_time_pad, raw_token) masked_token = one_time_pad + encrypted_csrf_token Base64.strict_encode64(masked_token) end @@ -307,28 +329,54 @@ module ActionController #:nodoc: compare_with_real_token masked_token, session elsif masked_token.length == AUTHENTICITY_TOKEN_LENGTH * 2 - # Split the token into the one-time pad and the encrypted - # value and decrypt it - one_time_pad = masked_token[0...AUTHENTICITY_TOKEN_LENGTH] - encrypted_csrf_token = masked_token[AUTHENTICITY_TOKEN_LENGTH..-1] - csrf_token = xor_byte_strings(one_time_pad, encrypted_csrf_token) - - compare_with_real_token csrf_token, session + csrf_token = unmask_token(masked_token) + compare_with_real_token(csrf_token, session) || + valid_per_form_csrf_token?(csrf_token, session) else false # Token is malformed end end + def unmask_token(masked_token) + # Split the token into the one-time pad and the encrypted + # value and decrypt it + one_time_pad = masked_token[0...AUTHENTICITY_TOKEN_LENGTH] + encrypted_csrf_token = masked_token[AUTHENTICITY_TOKEN_LENGTH..-1] + xor_byte_strings(one_time_pad, encrypted_csrf_token) + end + def compare_with_real_token(token, session) ActiveSupport::SecurityUtils.secure_compare(token, real_csrf_token(session)) end + def valid_per_form_csrf_token?(token, session) + if per_form_csrf_tokens + correct_token = per_form_csrf_token( + session, + normalize_action_path(request.fullpath), + request.request_method + ) + + ActiveSupport::SecurityUtils.secure_compare(token, correct_token) + else + false + end + end + def real_csrf_token(session) session[:_csrf_token] ||= SecureRandom.base64(AUTHENTICITY_TOKEN_LENGTH) Base64.strict_decode64(session[:_csrf_token]) end + def per_form_csrf_token(session, action_path, method) + OpenSSL::HMAC.digest( + OpenSSL::Digest::SHA256.new, + real_csrf_token(session), + [action_path, method.downcase].join("#") + ) + end + def xor_byte_strings(s1, s2) s1.bytes.zip(s2.bytes).map { |(c1,c2)| c1 ^ c2 }.pack('c*') end @@ -342,5 +390,20 @@ module ActionController #:nodoc: def protect_against_forgery? allow_forgery_protection end + + # Checks if the request originated from the same origin by looking at the + # Origin header. + def valid_request_origin? + if forgery_protection_origin_check + # We accept blank origin headers because some user agents don't send it. + request.origin.nil? || request.origin == request.base_url + else + true + end + end + + def normalize_action_path(action_path) + action_path.split('?').first.to_s.chomp('/') + end end end |