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# Copyright 2010 Dan Wanek <dan.wanek@gmail.com>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

require 'httpclient'
require_relative 'response_handler'

module WinRM
  module HTTP
    # A generic HTTP transport that utilized HTTPClient to send messages back and forth.
    # This backend will maintain state for every WinRMWebService instance that is instantiated so it
    # is possible to use GSSAPI with Keep-Alive.
    class HttpTransport
      attr_reader :endpoint

      def initialize(endpoint, options)
        @endpoint = endpoint.is_a?(String) ? URI.parse(endpoint) : endpoint
        @httpcli = HTTPClient.new(agent_name: 'Ruby WinRM Client')
        @logger = Logging.logger[self]
        @httpcli.receive_timeout = options[:receive_timeout]
      end

      # Sends the SOAP payload to the WinRM service and returns the service's
      # SOAP response. If an error occurrs an appropriate error is raised.
      #
      # @param [String] The XML SOAP message
      # @returns [REXML::Document] The parsed response body
      def send_request(message)
        ssl_peer_fingerprint_verification!
        log_soap_message(message)
        hdr = { 'Content-Type' => 'application/soap+xml;charset=UTF-8',
                'Content-Length' => message.bytesize }
        # We need to add this header if using Client Certificate authentication
        unless @httpcli.ssl_config.client_cert.nil?
          hdr['Authorization'] = 'http://schemas.dmtf.org/wbem/wsman/1/wsman/secprofile/https/mutual'
        end

        resp = @httpcli.post(@endpoint, message, hdr)
        log_soap_message(resp.http_body.content)
        verify_ssl_fingerprint(resp.peer_cert)
        handler = WinRM::ResponseHandler.new(resp.http_body.content, resp.status)
        handler.parse_to_xml
      end

      # We'll need this to force basic authentication if desired
      def basic_auth_only!
        auths = @httpcli.www_auth.instance_variable_get('@authenticator')
        auths.delete_if { |i| i.scheme !~ /basic/i }
      end

      # Disable SSPI Auth
      def no_sspi_auth!
        auths = @httpcli.www_auth.instance_variable_get('@authenticator')
        auths.delete_if { |i| i.is_a? HTTPClient::SSPINegotiateAuth }
      end

      # Disable SSL Peer Verification
      def no_ssl_peer_verification!
        @httpcli.ssl_config.verify_mode = OpenSSL::SSL::VERIFY_NONE
      end

      # SSL Peer Fingerprint Verification prior to connecting
      def ssl_peer_fingerprint_verification!
        return unless @ssl_peer_fingerprint && !@ssl_peer_fingerprint_verified

        with_untrusted_ssl_connection do |connection|
          connection_cert = connection.peer_cert
          verify_ssl_fingerprint(connection_cert)
        end
        @logger.info("initial ssl fingerprint #{@ssl_peer_fingerprint} verified\n")
        @ssl_peer_fingerprint_verified = true
        no_ssl_peer_verification!
      end

      # Connect without verification to retrieve untrusted ssl context
      def with_untrusted_ssl_connection
        noverify_peer_context = OpenSSL::SSL::SSLContext.new
        noverify_peer_context.verify_mode = OpenSSL::SSL::VERIFY_NONE
        tcp_connection = TCPSocket.new(@endpoint.host, @endpoint.port)
        begin
          ssl_connection = OpenSSL::SSL::SSLSocket.new(tcp_connection, noverify_peer_context)
          ssl_connection.connect
          yield ssl_connection
        ensure
          tcp_connection.close
        end
      end

      # compare @ssl_peer_fingerprint to current ssl context
      def verify_ssl_fingerprint(cert)
        return unless @ssl_peer_fingerprint

        conn_fingerprint = OpenSSL::Digest::SHA1.new(cert.to_der).to_s
        return unless @ssl_peer_fingerprint.casecmp(conn_fingerprint) != 0

        raise "ssl fingerprint mismatch!!!!\n"
      end

      protected

      def body(message, length, type = 'application/HTTP-SPNEGO-session-encrypted')
        [
          '--Encrypted Boundary',
          "Content-Type: #{type}",
          "OriginalContent: type=application/soap+xml;charset=UTF-8;Length=#{length}",
          '--Encrypted Boundary',
          'Content-Type: application/octet-stream',
          "#{message}--Encrypted Boundary--"
        ].join("\r\n").concat("\r\n")
      end

      def log_soap_message(message)
        return unless @logger.debug?

        xml_msg = REXML::Document.new(message)
        formatter = REXML::Formatters::Pretty.new(2)
        formatter.compact = true
        formatter.write(xml_msg, @logger)
        @logger.debug("\n")
      rescue StandardError => e
        @logger.debug("Couldn't log SOAP request/response: #{e.message} - #{message}")
      end
    end

    # Plain text, insecure, HTTP transport
    class HttpPlaintext < HttpTransport
      def initialize(endpoint, user, pass, opts)
        super(endpoint, opts)
        @httpcli.set_auth(nil, user, pass)
        no_sspi_auth! if opts[:disable_sspi]
        basic_auth_only! if opts[:basic_auth_only]
        no_ssl_peer_verification! if opts[:no_ssl_peer_verification]
      end
    end

    # NTLM/Negotiate, secure, HTTP transport
    class HttpNegotiate < HttpTransport
      def initialize(endpoint, user, pass, opts)
        super(endpoint, opts)
        require 'rubyntlm'
        no_sspi_auth!

        user_parts = user.split('\\')
        if user_parts.length > 1
          opts[:domain] = user_parts[0]
          user = user_parts[1]
        end

        @ntlmcli = Net::NTLM::Client.new(user, pass, opts)
        @retryable = true
        no_ssl_peer_verification! if opts[:no_ssl_peer_verification]
        @ssl_peer_fingerprint = opts[:ssl_peer_fingerprint]
        @httpcli.ssl_config.set_trust_ca(opts[:ca_trust_path]) if opts[:ca_trust_path]
      end

      def send_request(message)
        ssl_peer_fingerprint_verification!
        init_auth if @ntlmcli.session.nil?
        log_soap_message(message)

        hdr = {
          'Content-Type' => 'multipart/encrypted;'\
            'protocol="application/HTTP-SPNEGO-session-encrypted";boundary="Encrypted Boundary"'
        }

        resp = @httpcli.post(@endpoint, body(seal(message), message.bytesize), hdr)
        verify_ssl_fingerprint(resp.peer_cert)
        if resp.status == 401 && @retryable
          @retryable = false
          init_auth
          send_request(message)
        else
          @retryable = true
          decrypted_body = winrm_decrypt(resp)
          log_soap_message(decrypted_body)
          WinRM::ResponseHandler.new(decrypted_body, resp.status).parse_to_xml
        end
      end

      private

      def seal(message)
        emessage = @ntlmcli.session.seal_message message
        signature = @ntlmcli.session.sign_message message
        "\x10\x00\x00\x00#{signature}#{emessage}"
      end

      def winrm_decrypt(resp)
        # OMI server doesn't always respond to encrypted messages with encrypted responses over SSL
        return resp.body if resp.header['Content-Type'].first =~ %r{\Aapplication\/soap\+xml}i
        return '' if resp.body.empty?

        str = resp.body.force_encoding('BINARY')
        str.sub!(%r{^.*Content-Type: application\/octet-stream\r\n(.*)--Encrypted.*$}m, '\1')

        signature = str[4..19]
        message = @ntlmcli.session.unseal_message str[20..-1]
        return message if @ntlmcli.session.verify_signature(signature, message)

        raise WinRMHTTPTransportError, 'Could not decrypt NTLM message.'
      end

      def issue_challenge_response(negotiate)
        auth_header = {
          'Authorization' => "Negotiate #{negotiate.encode64}",
          'Content-Type' => 'application/soap+xml;charset=UTF-8'
        }

        # OMI Server on Linux requires an empty payload with the new auth header to proceed
        # because the config check for max payload size will otherwise break the auth handshake
        # given the OMI server does not support that check
        @httpcli.post(@endpoint, '', auth_header)

        # return an empty hash of headers for subsequent requests to use
        {}
      end

      def init_auth
        @logger.debug "Initializing Negotiate for #{@endpoint}"
        auth1 = @ntlmcli.init_context
        hdr = {
          'Authorization' => "Negotiate #{auth1.encode64}",
          'Content-Type' => 'application/soap+xml;charset=UTF-8'
        }
        @logger.debug 'Sending HTTP POST for Negotiate Authentication'
        r = @httpcli.post(@endpoint, '', hdr)
        verify_ssl_fingerprint(r.peer_cert)
        auth_header = r.header['WWW-Authenticate'].pop
        unless auth_header
          msg = "Unable to parse authorization header. Headers: #{r.headers}\r\nBody: #{r.body}"
          raise WinRMHTTPTransportError.new(msg, r.status_code)
        end
        itok = auth_header.split.last
        auth3 = @ntlmcli.init_context(itok, channel_binding(r))
        issue_challenge_response(auth3)
      end

      def channel_binding(response)
        if response.peer_cert.nil?
          nil
        else
          cert = if RUBY_PLATFORM == 'java'
                   OpenSSL::X509::Certificate.new(response.peer_cert.cert.getEncoded)
                 else
                   response.peer_cert
                 end
          Net::NTLM::ChannelBinding.create(OpenSSL::X509::Certificate.new(cert))
        end
      end
    end

    # Uses SSL to secure the transport
    class BasicAuthSSL < HttpTransport
      def initialize(endpoint, user, pass, opts)
        super(endpoint, opts)
        @httpcli.set_auth(endpoint, user, pass)
        basic_auth_only!
        no_ssl_peer_verification! if opts[:no_ssl_peer_verification]
        @ssl_peer_fingerprint = opts[:ssl_peer_fingerprint]
        @httpcli.ssl_config.set_trust_ca(opts[:ca_trust_path]) if opts[:ca_trust_path]
      end
    end

    # Uses Client Certificate to authenticate and SSL to secure the transport
    class ClientCertAuthSSL < HttpTransport
      def initialize(endpoint, client_cert, client_key, key_pass, opts)
        super(endpoint, opts)
        @httpcli.ssl_config.set_client_cert_file(client_cert, client_key, key_pass)
        @httpcli.www_auth.instance_variable_set('@authenticator', [])
        no_ssl_peer_verification! if opts[:no_ssl_peer_verification]
        @ssl_peer_fingerprint = opts[:ssl_peer_fingerprint]
        @httpcli.ssl_config.set_trust_ca(opts[:ca_trust_path]) if opts[:ca_trust_path]
      end
    end

    # Uses Kerberos/GSSAPI to authenticate and encrypt messages
    class HttpGSSAPI < HttpTransport
      # @param [String,URI] endpoint the WinRM webservice endpoint
      # @param [String] realm the Kerberos realm we are authenticating to
      # @param [String<optional>] service the service name, default is HTTP
      def initialize(endpoint, realm, opts, service = nil)
        require 'gssapi'
        require 'gssapi/extensions'

        super(endpoint, opts)
        # Remove the GSSAPI auth from HTTPClient because we are doing our own thing
        no_sspi_auth!
        service ||= 'HTTP'
        @service = "#{service}/#{@endpoint.host}@#{realm}"
        no_ssl_peer_verification! if opts[:no_ssl_peer_verification]
        init_krb
      end

      # Sends the SOAP payload to the WinRM service and returns the service's
      # SOAP response. If an error occurrs an appropriate error is raised.
      #
      # @param [String] The XML SOAP message
      # @returns [REXML::Document] The parsed response body
      def send_request(message)
        resp = send_kerberos_request(message)

        if resp.status == 401
          @logger.debug 'Got 401 - reinitializing Kerberos and retrying one more time'
          init_krb
          resp = send_kerberos_request(message)
        end

        handler = WinRM::ResponseHandler.new(winrm_decrypt(resp.http_body.content), resp.status)
        handler.parse_to_xml
      end

      private

      # Sends the SOAP payload to the WinRM service and returns the service's
      # HTTP response.
      #
      # @param [String] The XML SOAP message
      # @returns [Object] The HTTP response object
      def send_kerberos_request(message)
        log_soap_message(message)
        original_length = message.bytesize
        pad_len, emsg = winrm_encrypt(message)
        req_length = original_length + pad_len
        hdr = {
          'Connection' => 'Keep-Alive',
          'Content-Type' => 'multipart/encrypted;' \
            'protocol="application/HTTP-Kerberos-session-encrypted";boundary="Encrypted Boundary"'
        }

        resp = @httpcli.post(
          @endpoint,
          body(emsg, req_length, 'application/HTTP-Kerberos-session-encrypted'),
          hdr
        )
        log_soap_message(resp.http_body.content)
        resp
      end

      def init_krb
        @logger.debug "Initializing Kerberos for #{@service}"
        @gsscli = GSSAPI::Simple.new(@endpoint.host, @service)
        token = @gsscli.init_context
        auth = Base64.strict_encode64 token

        hdr = {
          'Authorization' => "Kerberos #{auth}",
          'Connection' => 'Keep-Alive',
          'Content-Type' => 'application/soap+xml;charset=UTF-8'
        }
        @logger.debug 'Sending HTTP POST for Kerberos Authentication'
        r = @httpcli.post(@endpoint, '', hdr)
        itok = r.header['WWW-Authenticate'].pop
        itok = itok.split.last
        itok = Base64.strict_decode64(itok)
        @gsscli.init_context(itok)
      end

      # rubocop:disable Metrics/MethodLength
      # rubocop:disable Metrics/AbcSize

      # @return [String] the encrypted request string
      def winrm_encrypt(str)
        @logger.debug "Encrypting SOAP message:\n#{str}"
        iov_cnt = 3
        iov = FFI::MemoryPointer.new(GSSAPI::LibGSSAPI::GssIOVBufferDesc.size * iov_cnt)

        iov0 = GSSAPI::LibGSSAPI::GssIOVBufferDesc.new(FFI::Pointer.new(iov.address))
        iov0[:type] = (GSSAPI::LibGSSAPI::GSS_IOV_BUFFER_TYPE_HEADER | \
          GSSAPI::LibGSSAPI::GSS_IOV_BUFFER_FLAG_ALLOCATE)

        iov1 = GSSAPI::LibGSSAPI::GssIOVBufferDesc.new(
          FFI::Pointer.new(iov.address + (GSSAPI::LibGSSAPI::GssIOVBufferDesc.size * 1))
        )
        iov1[:type] = GSSAPI::LibGSSAPI::GSS_IOV_BUFFER_TYPE_DATA
        iov1[:buffer].value = str

        iov2 = GSSAPI::LibGSSAPI::GssIOVBufferDesc.new(
          FFI::Pointer.new(iov.address + (GSSAPI::LibGSSAPI::GssIOVBufferDesc.size * 2))
        )
        iov2[:type] = (GSSAPI::LibGSSAPI::GSS_IOV_BUFFER_TYPE_PADDING | \
          GSSAPI::LibGSSAPI::GSS_IOV_BUFFER_FLAG_ALLOCATE)

        conf_state = FFI::MemoryPointer.new :uint32
        min_stat = FFI::MemoryPointer.new :uint32

        GSSAPI::LibGSSAPI.gss_wrap_iov(
          min_stat,
          @gsscli.context,
          1,
          GSSAPI::LibGSSAPI::GSS_C_QOP_DEFAULT,
          conf_state,
          iov,
          iov_cnt
        )

        token = [iov0[:buffer].length].pack('L')
        token += iov0[:buffer].value
        token += iov1[:buffer].value
        pad_len = iov2[:buffer].length
        token += iov2[:buffer].value if pad_len > 0
        [pad_len, token]
      end

      # @return [String] the unencrypted response string
      def winrm_decrypt(str)
        @logger.debug "Decrypting SOAP message:\n#{str}"
        iov_cnt = 3
        iov = FFI::MemoryPointer.new(GSSAPI::LibGSSAPI::GssIOVBufferDesc.size * iov_cnt)

        iov0 = GSSAPI::LibGSSAPI::GssIOVBufferDesc.new(FFI::Pointer.new(iov.address))
        iov0[:type] = (GSSAPI::LibGSSAPI::GSS_IOV_BUFFER_TYPE_HEADER | \
          GSSAPI::LibGSSAPI::GSS_IOV_BUFFER_FLAG_ALLOCATE)

        iov1 = GSSAPI::LibGSSAPI::GssIOVBufferDesc.new(
          FFI::Pointer.new(iov.address + (GSSAPI::LibGSSAPI::GssIOVBufferDesc.size * 1))
        )
        iov1[:type] = GSSAPI::LibGSSAPI::GSS_IOV_BUFFER_TYPE_DATA

        iov2 = GSSAPI::LibGSSAPI::GssIOVBufferDesc.new(
          FFI::Pointer.new(iov.address + (GSSAPI::LibGSSAPI::GssIOVBufferDesc.size * 2))
        )
        iov2[:type] = GSSAPI::LibGSSAPI::GSS_IOV_BUFFER_TYPE_DATA

        str.force_encoding('BINARY')
        str.sub!(%r{^.*Content-Type: application\/octet-stream\r\n(.*)--Encrypted.*$}m, '\1')

        len = str.unpack('L').first
        iov_data = str.unpack("La#{len}a*")
        iov0[:buffer].value = iov_data[1]
        iov1[:buffer].value = iov_data[2]

        min_stat = FFI::MemoryPointer.new :uint32
        conf_state = FFI::MemoryPointer.new :uint32
        conf_state.write_int(1)
        qop_state = FFI::MemoryPointer.new :uint32
        qop_state.write_int(0)

        maj_stat = GSSAPI::LibGSSAPI.gss_unwrap_iov(
          min_stat, @gsscli.context, conf_state, qop_state, iov, iov_cnt
        )

        @logger.debug "SOAP message decrypted (MAJ: #{maj_stat}, " \
          "MIN: #{min_stat.read_int}):\n#{iov1[:buffer].value}"

        iov1[:buffer].value
      end
      # rubocop:enable Metrics/MethodLength
      # rubocop:enable Metrics/AbcSize
    end
  end
end
# WinRM