require 'active_support/base64' 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.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 # Raises error 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]) [true, false].any? do |password_is_ha1| expected = expected_response(request.env['REQUEST_METHOD'], request.env['REQUEST_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(":")) ActiveSupport::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 = ActiveSupport::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