instiki/vendor/rails/actionpack/lib/action_controller/http_authentication.rb
Jacques Distler 4bdf703ab2 Instiki 0.17.2: Security Release
This release upgrades Instiki to Rails 2.3.4, which
patches two security holes in Rails. See

  http://weblog.rubyonrails.org/2009/9/4/ruby-on-rails-2-3-4

There are also some new features, and the usual boatload
of bugfixes. See the CHANGELOG for details.
2009-09-05 02:01:46 -05:00

309 lines
13 KiB
Ruby

module ActionController
module HttpAuthentication
# Makes it dead easy to do HTTP Basic authentication.
#
# Simple Basic example:
#
# class PostsController < ApplicationController
# USER_NAME, PASSWORD = "dhh", "secret"
#
# before_filter :authenticate, :except => [ :index ]
#
# def index
# render :text => "Everyone can see me!"
# end
#
# def edit
# render :text => "I'm only accessible if you know the password"
# end
#
# private
# def authenticate
# authenticate_or_request_with_http_basic do |user_name, password|
# user_name == USER_NAME && password == PASSWORD
# end
# end
# end
#
#
# 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_filter :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
# get(
# "/notes/1.xml", nil,
# :authorization => ActionController::HttpAuthentication::Basic.encode_credentials(users(:dhh).name, users(:dhh).password)
# )
#
# assert_equal 200, status
# end
#
# 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_filter :authenticate, :except => [:index]
#
# def index
# render :text => "Everyone can see me!"
# end
#
# def edit
# render :text => "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
#
# NOTE: 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.
#
# 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 Basic
extend self
module ControllerMethods
def authenticate_or_request_with_http_basic(realm = "Application", &login_procedure)
authenticate_with_http_basic(&login_procedure) || request_http_basic_authentication(realm)
end
def authenticate_with_http_basic(&login_procedure)
HttpAuthentication::Basic.authenticate(self, &login_procedure)
end
def request_http_basic_authentication(realm = "Application")
HttpAuthentication::Basic.authentication_request(self, realm)
end
end
def authenticate(controller, &login_procedure)
unless authorization(controller.request).blank?
login_procedure.call(*user_name_and_password(controller.request))
end
end
def user_name_and_password(request)
decode_credentials(request).split(/:/, 2)
end
def authorization(request)
request.env['HTTP_AUTHORIZATION'] ||
request.env['X-HTTP_AUTHORIZATION'] ||
request.env['X_HTTP_AUTHORIZATION'] ||
request.env['REDIRECT_X_HTTP_AUTHORIZATION']
end
def decode_credentials(request)
ActiveSupport::Base64.decode64(authorization(request).split(' ', 2).last || '')
end
def encode_credentials(user_name, password)
"Basic #{ActiveSupport::Base64.encode64("#{user_name}:#{password}")}"
end
def authentication_request(controller, realm)
controller.headers["WWW-Authenticate"] = %(Basic realm="#{realm.gsub(/"/, "")}")
controller.__send__ :render, :text => "HTTP Basic: Access denied.\n", :status => :unauthorized
end
end
module Digest
extend self
module ControllerMethods
def authenticate_or_request_with_http_digest(realm = "Application", &password_procedure)
authenticate_with_http_digest(realm, &password_procedure) || request_http_digest_authentication(realm)
end
# Authenticate with HTTP Digest, returns true or false
def authenticate_with_http_digest(realm = "Application", &password_procedure)
HttpAuthentication::Digest.authenticate(self, 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(controller, realm, &password_procedure)
authorization(controller.request) && validate_digest_response(controller.request, realm, &password_procedure)
end
def authorization(request)
request.env['HTTP_AUTHORIZATION'] ||
request.env['X-HTTP_AUTHORIZATION'] ||
request.env['X_HTTP_AUTHORIZATION'] ||
request.env['REDIRECT_X_HTTP_AUTHORIZATION']
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)
credentials = decode_credentials_header(request)
valid_nonce = validate_nonce(request, credentials[:nonce])
if valid_nonce && realm == credentials[:realm] && opaque == credentials[:opaque]
password = password_procedure.call(credentials[:username])
return false unless password
method = request.env['rack.methodoverride.original_method'] || request.env['REQUEST_METHOD']
uri = credentials[:uri][0,1] == '/' ? request.request_uri : request.url
[true, false].any? do |password_is_ha1|
expected = expected_response(method, uri, credentials, password, password_is_ha1)
expected == credentials[:response]
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 }.inject([]) {|a, v| a << "#{v[0]}='#{v[1]}'" }.join(', ')
end
def decode_credentials_header(request)
decode_credentials(authorization(request))
end
def decode_credentials(header)
header.to_s.gsub(/^Digest\s+/,'').split(',').inject({}) do |hash, pair|
key, value = pair.split('=', 2)
hash[key.strip.to_sym] = value.to_s.gsub(/^"|"$/,'').gsub(/'/, '')
hash
end
end
def authentication_header(controller, realm)
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.__send__ :render, :text => message, :status => :unauthorized
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 or PUT 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 modifed by client.
def nonce(time = Time.now)
t = time.to_i
hashed = [t, secret_key]
digest = ::Digest::MD5.hexdigest(hashed.join(":"))
Base64.encode64("#{t}:#{digest}").gsub("\n", '')
end
# Might want a shorter timeout depending on whether the request
# is a PUT or POST, and if client is 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 user again for their
# username and password.
def validate_nonce(request, value, seconds_to_timeout=5*60)
t = Base64.decode64(value).split(":").first.to_i
nonce(t) == value && (t - Time.now.to_i).abs <= seconds_to_timeout
end
# Opaque based on random generation - but changing each request?
def opaque()
::Digest::MD5.hexdigest(secret_key)
end
# Set in /initializers/session_store.rb, and loaded even if sessions are not in use.
def secret_key
ActionController::Base.session_options[:secret]
end
end
end
end