Class: Rack::TCTP

Inherits:
Object
  • Object
show all
Defined in:
lib/rack/tctp.rb,
ext/engine/engine.c

Overview

This middleware enables Rack to make use of the Trusted Cloud Transfer Protocol (TCTP) for HTTP end-to-end body confidentiality and integrity.

Defined Under Namespace

Classes: ClientHALEC, Engine, HALEC, SSLError, ServerHALEC

Constant Summary collapse

DEFAULT_TCTP_DISCOVERY_INFORMATION = 
'/.*:/halecs'
TCTP_DISCOVERY_MEDIA_TYPE = 
'text/prs.tctp-discovery'
TCTP_MEDIA_TYPE = 
'binary/prs.tctp'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app, logger = nil) ⇒ TCTP

Initializes TCTP middleware



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# File 'lib/rack/tctp.rb', line 28

def initialize(app, logger = nil)
  unless logger
    @logger = ::Logger.new(STDOUT)
    @logger.level = ::Logger::FATAL
  else
    @logger = logger
  end

  @app = app
  @sessions = {}
end

Instance Attribute Details

#sessions ⇒ Object (readonly)

The TCTP sessions



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# File 'lib/rack/tctp.rb', line 25

def sessions
  @sessions
end

Class Method Details

.new_slug ⇒ Object

Generate a new random slug (2^64 possibilities)



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# File 'lib/rack/tctp.rb', line 20

def self.new_slug
  slug_base.convert(rand(2**64), 10)
end

.slug_base ⇒ Object

The slug URI can contain any HTTP compatible characters



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# File 'lib/rack/tctp.rb', line 15

def self.slug_base
  Radix::Base.new(Radix::BASE::B62 + ['-', '_'])
end

Instance Method Details

#call(env) ⇒ Object

Middleware call. Supports all TCTP use cases:

  • TCTP discovery

  • HALEC creation

  • HALEC handshake

  • Decrypting TCTP secured entity-bodies

  • Encrypting entity-bodies using TCTP



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# File 'lib/rack/tctp.rb', line 46

def call(env)
  status, headers, body = nil, nil, nil

  begin
    req = Rack::Request.new(env)

    case
      when is_tctp_discovery?(req)
        # TCTP discovery
        # TODO Parameterize discovery information
        [200, {"Content-Type" => TCTP_DISCOVERY_MEDIA_TYPE, "Content-Length" => DEFAULT_TCTP_DISCOVERY_INFORMATION.length.to_s}, [DEFAULT_TCTP_DISCOVERY_INFORMATION]]
      when is_halec_creation?(req)
        # HALEC creation
        halec = ServerHALEC.new(url: halec_uri(req.env, "/halecs/#{TCTP::new_slug}"))

        session = sessions[req.cookies['tctp_session_cookie']] || TCTPSession.new

        # Send client_hello to server HALEC and read handshake_response
        client_hello = req.body.read
        halec.engine.inject client_hello
        halec.engine.read
        handshake_response = [halec.engine.extract]

        # Set location header and content-length
        header = {
            'Location' => halec.url.to_s,
            'Content-Length' => handshake_response[0].length.to_s,
            'Content-Type' => TCTP_MEDIA_TYPE
        }

        # Set the TCTP session cookie header
        Rack::Utils.set_cookie_header!(header, "tctp_session_cookie", {:value => session.session_id, :path => '/', :expires => Time.now+24*60*60})

        # Persist session and HALEC
        session.push_halec(halec)
        sessions[session.session_id] = session

        [201, header, handshake_response]
      when is_halec_handshake?(req)
        # Get persisted server HALEC
        halec = @sessions[req.cookies['tctp_session_cookie']].halecs[halec_uri(req.env, req.path_info)]

        # Write handshake message to server HALEC
        halec.engine.inject req.body.read

        # Receive handshake response
        halec.engine.read
        handshake_response = halec.engine.extract

        # Send back server HALEC response
        [200, {
            'Content-Length' => handshake_response.length.to_s,
            'Content-Type' => TCTP_MEDIA_TYPE
        }, [handshake_response]]
      else
        # Decrypt TCTP secured bodies
        if is_tctp_encrypted_body?(req) then
          decrypted_body = StringIO.new

          halec_url = req.body.gets.chomp

          # Gets the HALEC
          halec = @sessions[req.cookies['tctp_session_cookie']].halecs[URI(halec_url)]

          read_body = req.body.read

          begin
            decrypted_body.write halec.decrypt_data(read_body)
          rescue Exception => e
            error(e.message + e.backtrace.join("<br/>\n"))
          end

          decrypted_body.rewind

          env['rack.input'] = decrypted_body
        end

        status, headers, body = @app.call(env)

        if is_tctp_response_requested?(req) && status >= 200 && ![204, 205, 304].include?(status)
          # Gets the first free server HALEC for encryption
          # TODO Send error if cookie is missing
          session = @sessions[req.cookies['tctp_session_cookie']]

          unless session
            return no_usable_halec_error
          end

          halec = session.pop_halec

          unless halec
            return no_usable_halec_error
          end

          # The length of the content body
          content_body_length = 0

          # The first line
          first_line = halec.url.to_s + "\r\n"
          content_body_length += first_line.length

          # Encrypt the body. The first line of the response specifies the used HALEC
          encrypted_body = []
          encrypted_body << first_line

          # Encrypt each body fragment
          body.each do |fragment|
            encrypted_fragment = halec.encrypt_data fragment
            encrypted_body << encrypted_fragment
            content_body_length += encrypted_fragment.length
          end

          encrypted_body.define_singleton_method :close do
            session.push_halec halec

            super() if self.class.superclass.respond_to? :close
          end

          # Finding this bug took waaaay too long ...
          body.close if body.respond_to?(:close)

          # Sets the content length and encoding
          headers['Content-Length'] = content_body_length.to_s
          headers['Content-Encoding'] = 'encrypted'

          [status, headers, encrypted_body]
        else
          [status, headers, body]
        end
    end
  rescue Exception => e
    # TODO Handle SSL Error
    @logger.fatal e

    error "Error in TCTP middleware. #{e} #{e.backtrace.inspect}"
  end
end