require "base64"
require "active_support/security_utils"
module ActionController
# Makes it dead easy to do HTTP Basic, Digest and Token authentication.
module HttpAuthentication
# Makes it dead easy to do HTTP \Basic authentication.
#
# === Simple \Basic example
#
# class PostsController < ApplicationController
# http_basic_authenticate_with name: "dhh", password: "secret", except: :index
#
# def index
# render plain: "Everyone can see me!"
# end
#
# def edit
# render plain: "I'm only accessible if you know the password"
# end
# end
#
# === Advanced \Basic example
#
# Here is a more advanced \Basic example where only Atom feeds and the XML API is protected by HTTP authentication,
# the regular HTML interface is protected by a session approach:
#
# class ApplicationController < ActionController::Base
# before_action :set_account, :authenticate
#
# protected
# def set_account
# @account = Account.find_by(url_name: request.subdomains.first)
# end
#
# def authenticate
# case request.format
# when Mime[:xml], Mime[:atom]
# if user = authenticate_with_http_basic { |u, p| @account.users.authenticate(u, p) }
# @current_user = user
# else
# request_http_basic_authentication
# end
# else
# if session_authenticated?
# @current_user = @account.users.find(session[:authenticated][:user_id])
# else
# redirect_to(login_url) and return false
# end
# end
# end
# end
#
# In your integration tests, you can do something like this:
#
# def test_access_granted_from_xml
# @request.env['HTTP_AUTHORIZATION'] = ActionController::HttpAuthentication::Basic.encode_credentials(users(:dhh).name, users(:dhh).password)
# get "/notes/1.xml"
#
# assert_equal 200, status
# end
module Basic
extend self
module ControllerMethods
extend ActiveSupport::Concern
module ClassMethods
def http_basic_authenticate_with(options = {})
before_action(options.except(:name, :password, :realm)) do
authenticate_or_request_with_http_basic(options[:realm] || "Application") do |name, password|
# This comparison uses & so that it doesn't short circuit and
# uses `variable_size_secure_compare` so that length information
# isn't leaked.
ActiveSupport::SecurityUtils.variable_size_secure_compare(name, options[:name]) &
ActiveSupport::SecurityUtils.variable_size_secure_compare(password, options[:password])
end
end
end
end
def authenticate_or_request_with_http_basic(realm = "Application", message = nil, &login_procedure)
authenticate_with_http_basic(&login_procedure) || request_http_basic_authentication(realm, message)
end
def authenticate_with_http_basic(&login_procedure)
HttpAuthentication::Basic.authenticate(request, &login_procedure)
end
def request_http_basic_authentication(realm = "Application", message = nil)
HttpAuthentication::Basic.authentication_request(self, realm, message)
end
end
def authenticate(request, &login_procedure)
if has_basic_credentials?(request)
login_procedure.call(*user_name_and_password(request))
end
end
def has_basic_credentials?(request)
request.authorization.present? && (auth_scheme(request).downcase == "basic")
end
def user_name_and_password(request)
decode_credentials(request).split(":", 2)
end
def decode_credentials(request)
::Base64.decode64(auth_param(request) || "")
end
def auth_scheme(request)
request.authorization.to_s.split(" ", 2).first
end
def auth_param(request)
request.authorization.to_s.split(" ", 2).second
end
def encode_credentials(user_name, password)
"Basic #{::Base64.strict_encode64("#{user_name}:#{password}")}"
end
def authentication_request(controller, realm, message)
message ||= "HTTP Basic: Access denied.\n"
controller.headers["WWW-Authenticate"] = %(Basic realm="#{realm.tr('"'.freeze, "".freeze)}")
controller.status = 401
controller.response_body = message
end
end
# Makes it dead easy to do HTTP \Digest authentication.
#
# === Simple \Digest example
#
# require 'digest/md5'
# class PostsController < ApplicationController
# REALM = "SuperSecret"
# USERS = {"dhh" => "secret", #plain text password
# "dap" => Digest::MD5.hexdigest(["dap",REALM,"secret"].join(":"))} #ha1 digest password
#
# before_action :authenticate, except: [:index]
#
# def index
# render plain: "Everyone can see me!"
# end
#
# def edit
# render plain: "I'm only accessible if you know the password"
# end
#
# private
# def authenticate
# authenticate_or_request_with_http_digest(REALM) do |username|
# USERS[username]
# end
# end
# end
#
# === Notes
#
# The +authenticate_or_request_with_http_digest+ block must return the user's password
# or the ha1 digest hash so the framework can appropriately hash to check the user's
# credentials. Returning +nil+ will cause authentication to fail.
#
# Storing the ha1 hash: MD5(username:realm:password), is better than storing a plain password. If
# the password file or database is compromised, the attacker would be able to use the ha1 hash to
# authenticate as the user at this +realm+, but would not have the user's password to try using at
# other sites.
#
# In rare instances, web servers or front proxies strip authorization headers before
# they reach your application. You can debug this situation by logging all environment
# variables, and check for HTTP_AUTHORIZATION, amongst others.
module Digest
extend self
module ControllerMethods
def authenticate_or_request_with_http_digest(realm = "Application", message = nil, &password_procedure)
authenticate_with_http_digest(realm, &password_procedure) || request_http_digest_authentication(realm, message)
end
# Authenticate with HTTP Digest, returns true or false
def authenticate_with_http_digest(realm = "Application", &password_procedure)
HttpAuthentication::Digest.authenticate(request, realm, &password_procedure)
end
# Render output including the HTTP Digest authentication header
def request_http_digest_authentication(realm = "Application", message = nil)
HttpAuthentication::Digest.authentication_request(self, realm, message)
end
end
# Returns false on a valid response, true otherwise
def authenticate(request, realm, &password_procedure)
request.authorization && validate_digest_response(request, realm, &password_procedure)
end
# Returns false unless the request credentials response value matches the expected value.
# First try the password as a ha1 digest password. If this fails, then try it as a plain
# text password.
def validate_digest_response(request, realm, &password_procedure)
secret_key = secret_token(request)
credentials = decode_credentials_header(request)
valid_nonce = validate_nonce(secret_key, request, credentials[:nonce])
if valid_nonce && realm == credentials[:realm] && opaque(secret_key) == credentials[:opaque]
password = password_procedure.call(credentials[:username])
return false unless password
method = request.get_header("rack.methodoverride.original_method") || request.get_header("REQUEST_METHOD")
uri = credentials[:uri]
[true, false].any? do |trailing_question_mark|
[true, false].any? do |password_is_ha1|
_uri = trailing_question_mark ? uri + "?" : uri
expected = expected_response(method, _uri, credentials, password, password_is_ha1)
expected == credentials[:response]
end
end
end
end
# Returns the expected response for a request of +http_method+ to +uri+ with the decoded +credentials+ and the expected +password+
# Optional parameter +password_is_ha1+ is set to +true+ by default, since best practice is to store ha1 digest instead
# of a plain-text password.
def expected_response(http_method, uri, credentials, password, password_is_ha1=true)
ha1 = password_is_ha1 ? password : ha1(credentials, password)
ha2 = ::Digest::MD5.hexdigest([http_method.to_s.upcase, uri].join(":"))
::Digest::MD5.hexdigest([ha1, credentials[:nonce], credentials[:nc], credentials[:cnonce], credentials[:qop], ha2].join(":"))
end
def ha1(credentials, password)
::Digest::MD5.hexdigest([credentials[:username], credentials[:realm], password].join(":"))
end
def encode_credentials(http_method, credentials, password, password_is_ha1)
credentials[:response] = expected_response(http_method, credentials[:uri], credentials, password, password_is_ha1)
"Digest " + credentials.sort_by { |x| x[0].to_s }.map { |v| "#{v[0]}='#{v[1]}'" }.join(", ")
end
def decode_credentials_header(request)
decode_credentials(request.authorization)
end
def decode_credentials(header)
ActiveSupport::HashWithIndifferentAccess[header.to_s.gsub(/^Digest\s+/, "").split(",").map do |pair|
key, value = pair.split("=", 2)
[key.strip, value.to_s.gsub(/^"|"$/,"").delete('\'')]
end]
end
def authentication_header(controller, realm)
secret_key = secret_token(controller.request)
nonce = self.nonce(secret_key)
opaque = opaque(secret_key)
controller.headers["WWW-Authenticate"] = %(Digest realm="#{realm}", qop="auth", algorithm=MD5, nonce="#{nonce}", opaque="#{opaque}")
end
def authentication_request(controller, realm, message = nil)
message ||= "HTTP Digest: Access denied.\n"
authentication_header(controller, realm)
controller.status = 401
controller.response_body = message
end
def secret_token(request)
key_generator = request.key_generator
http_auth_salt = request.http_auth_salt
key_generator.generate_key(http_auth_salt)
end
# Uses an MD5 digest based on time to generate a value to be used only once.
#
# A server-specified data string which should be uniquely generated each time a 401 response is made.
# It is recommended that this string be base64 or hexadecimal data.
# Specifically, since the string is passed in the header lines as a quoted string, the double-quote character is not allowed.
#
# The contents of the nonce are implementation dependent.
# The quality of the implementation depends on a good choice.
# A nonce might, for example, be constructed as the base 64 encoding of
#
# time-stamp H(time-stamp ":" ETag ":" private-key)
#
# where time-stamp is a server-generated time or other non-repeating value,
# ETag is the value of the HTTP ETag header associated with the requested entity,
# and private-key is data known only to the server.
# With a nonce of this form a server would recalculate the hash portion after receiving the client authentication header and
# reject the request if it did not match the nonce from that header or
# if the time-stamp value is not recent enough. In this way the server can limit the time of the nonce's validity.
# The inclusion of the ETag prevents a replay request for an updated version of the resource.
# (Note: including the IP address of the client in the nonce would appear to offer the server the ability
# to limit the reuse of the nonce to the same client that originally got it.
# However, that would break proxy farms, where requests from a single user often go through different proxies in the farm.
# Also, IP address spoofing is not that hard.)
#
# An implementation might choose not to accept a previously used nonce or a previously used digest, in order to
# protect against a replay attack. Or, an implementation might choose to use one-time nonces or digests for
# POST, PUT, or PATCH requests and a time-stamp for GET requests. For more details on the issues involved see Section 4
# of this document.
#
# The nonce is opaque to the client. Composed of Time, and hash of Time with secret
# key from the Rails session secret generated upon creation of project. Ensures
# the time cannot be modified by client.
def nonce(secret_key, time = Time.now)
t = time.to_i
hashed = [t, secret_key]
digest = ::Digest::MD5.hexdigest(hashed.join(":"))
::Base64.strict_encode64("#{t}:#{digest}")
end
# Might want a shorter timeout depending on whether the request
# is a PATCH, PUT, or POST, and if the client is a browser or web service.
# Can be much shorter if the Stale directive is implemented. This would
# allow a user to use new nonce without prompting the user again for their
# username and password.
def validate_nonce(secret_key, request, value, seconds_to_timeout=5*60)
return false if value.nil?
t = ::Base64.decode64(value).split(":").first.to_i
nonce(secret_key, t) == value && (t - Time.now.to_i).abs <= seconds_to_timeout
end
# Opaque based on digest of secret key
def opaque(secret_key)
::Digest::MD5.hexdigest(secret_key)
end
end
# Makes it dead easy to do HTTP Token authentication.
#
# Simple Token example:
#
# class PostsController < ApplicationController
# TOKEN = "secret"
#
# before_action :authenticate, except: [ :index ]
#
# def index
# render plain: "Everyone can see me!"
# end
#
# def edit
# render plain: "I'm only accessible if you know the password"
# end
#
# private
# def authenticate
# authenticate_or_request_with_http_token do |token, options|
# # Compare the tokens in a time-constant manner, to mitigate
# # timing attacks.
# ActiveSupport::SecurityUtils.secure_compare(
# ::Digest::SHA256.hexdigest(token),
# ::Digest::SHA256.hexdigest(TOKEN)
# )
# end
# end
# end
#
#
# Here is a more advanced Token example where only Atom feeds and the XML API is protected by HTTP token authentication,
# the regular HTML interface is protected by a session approach:
#
# class ApplicationController < ActionController::Base
# before_action :set_account, :authenticate
#
# protected
# def set_account
# @account = Account.find_by(url_name: request.subdomains.first)
# end
#
# def authenticate
# case request.format
# when Mime[:xml], Mime[:atom]
# if user = authenticate_with_http_token { |t, o| @account.users.authenticate(t, o) }
# @current_user = user
# else
# request_http_token_authentication
# end
# else
# if session_authenticated?
# @current_user = @account.users.find(session[:authenticated][:user_id])
# else
# redirect_to(login_url) and return false
# end
# end
# end
# end
#
#
# In your integration tests, you can do something like this:
#
# def test_access_granted_from_xml
# get(
# "/notes/1.xml", nil,
# 'HTTP_AUTHORIZATION' => ActionController::HttpAuthentication::Token.encode_credentials(users(:dhh).token)
# )
#
# assert_equal 200, status
# end
#
#
# On shared hosts, Apache sometimes doesn't pass authentication headers to
# FCGI instances. If your environment matches this description and you cannot
# authenticate, try this rule in your Apache setup:
#
# RewriteRule ^(.*)$ dispatch.fcgi [E=X-HTTP_AUTHORIZATION:%{HTTP:Authorization},QSA,L]
module Token
TOKEN_KEY = "token="
TOKEN_REGEX = /^(Token|Bearer)\s+/
AUTHN_PAIR_DELIMITERS = /(?:,|;|\t+)/
extend self
module ControllerMethods
def authenticate_or_request_with_http_token(realm = "Application", message = nil, &login_procedure)
authenticate_with_http_token(&login_procedure) || request_http_token_authentication(realm, message)
end
def authenticate_with_http_token(&login_procedure)
Token.authenticate(self, &login_procedure)
end
def request_http_token_authentication(realm = "Application", message = nil)
Token.authentication_request(self, realm, message)
end
end
# If token Authorization header is present, call the login
# procedure with the present token and options.
#
# [controller]
# ActionController::Base instance for the current request.
#
# [login_procedure]
# Proc to call if a token is present. The Proc should take two arguments:
#
# authenticate(controller) { |token, options| ... }
#
# Returns the return value of login_procedure if a
# token is found. Returns nil if no token is found.
def authenticate(controller, &login_procedure)
token, options = token_and_options(controller.request)
unless token.blank?
login_procedure.call(token, options)
end
end
# Parses the token and options out of the token authorization header.
# The value for the Authorization header is expected to have the prefix
# "Token" or "Bearer". If the header looks like this:
# Authorization: Token token="abc", nonce="def"
# Then the returned token is "abc", and the options are
# {nonce: "def"}
#
# request - ActionDispatch::Request instance with the current headers.
#
# Returns an +Array+ of [String, Hash] if a token is present.
# Returns +nil+ if no token is found.
def token_and_options(request)
authorization_request = request.authorization.to_s
if authorization_request[TOKEN_REGEX]
params = token_params_from authorization_request
[params.shift[1], Hash[params].with_indifferent_access]
end
end
def token_params_from(auth)
rewrite_param_values params_array_from raw_params auth
end
# Takes raw_params and turns it into an array of parameters
def params_array_from(raw_params)
raw_params.map { |param| param.split %r/=(.+)?/ }
end
# This removes the " characters wrapping the value.
def rewrite_param_values(array_params)
array_params.each { |param| (param[1] || "").gsub! %r/^"|"$/, "" }
end
# This method takes an authorization body and splits up the key-value
# pairs by the standardized :, ;, or \t
# delimiters defined in +AUTHN_PAIR_DELIMITERS+.
def raw_params(auth)
_raw_params = auth.sub(TOKEN_REGEX, "").split(/\s*#{AUTHN_PAIR_DELIMITERS}\s*/)
if !(_raw_params.first =~ %r{\A#{TOKEN_KEY}})
_raw_params[0] = "#{TOKEN_KEY}#{_raw_params.first}"
end
_raw_params
end
# Encodes the given token and options into an Authorization header value.
#
# token - String token.
# options - optional Hash of the options.
#
# Returns String.
def encode_credentials(token, options = {})
values = ["#{TOKEN_KEY}#{token.to_s.inspect}"] + options.map do |key, value|
"#{key}=#{value.to_s.inspect}"
end
"Token #{values * ", "}"
end
# Sets a WWW-Authenticate header to let the client know a token is desired.
#
# controller - ActionController::Base instance for the outgoing response.
# realm - String realm to use in the header.
#
# Returns nothing.
def authentication_request(controller, realm, message = nil)
message ||= "HTTP Token: Access denied.\n"
controller.headers["WWW-Authenticate"] = %(Token realm="#{realm.tr('"'.freeze, "".freeze)}")
controller.__send__ :render, plain: message, status: :unauthorized
end
end
end
end