Add MS-GKDI Structures

lib/ruby_smb/dcerpc.rb

@@ -50,6 +50,7 @@ module Dcerpc
     require 'ruby_smb/dcerpc/icpr'
     require 'ruby_smb/dcerpc/efsrpc'
     require 'ruby_smb/dcerpc/lsarpc'
+    require 'ruby_smb/dcerpc/gkdi'
     require 'ruby_smb/dcerpc/request'
     require 'ruby_smb/dcerpc/response'
     require 'ruby_smb/dcerpc/rpc_auth3'

lib/ruby_smb/dcerpc/error.rb

@@ -70,6 +70,16 @@ def initialize(msg, status_code: nil)
           super(msg)
         end
       end
+
+      class GkdiError < DcerpcError
+        include RubySMB::Error::UnexpectedStatusCode::Mixin
+
+        def initialize(msg, status_code: nil)
+          self.status_code = status_code unless status_code.nil?
+
+          super(msg)
+        end
+      end
     end
   end
 end

lib/ruby_smb/dcerpc/gkdi.rb

@@ -0,0 +1,54 @@
+module RubySMB
+  module Dcerpc
+    module Gkdi
+
+      # [2.1 Transport](https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-gkdi/2ca63ad2-2464-4a41-ba84-2e0270e95e86)
+      UUID = 'b9785960-524f-11df-8b6d-83dcded72085'
+      VER_MAJOR = 1
+      VER_MINOR = 0
+
+      # Operation numbers
+      GKDI_GET_KEY = 0x0000
+
+      require 'ruby_smb/dcerpc/gkdi/gkdi_get_key_request'
+      require 'ruby_smb/dcerpc/gkdi/gkdi_get_key_response'
+      require 'ruby_smb/dcerpc/gkdi/gkdi_ffc_dh_key'
+      require 'ruby_smb/dcerpc/gkdi/gkdi_ffc_dh_parameters'
+      require 'ruby_smb/dcerpc/gkdi/gkdi_group_key_envelope'
+
+      def gkdi_get_key(target_sd, root_key_id, l0_key_id, l1_key_id, l2_key_id)
+        target_sd = target_sd.to_binary_s if target_sd.respond_to?(:to_binary_s)
+
+        gkdi_get_key_request = GkdiGetKeyRequest.new(
+          cb_target_sd: target_sd.length,
+          pb_target_sd: target_sd.unpack('C*'),
+          p_root_key_id: root_key_id,
+          l0_key_id: l0_key_id,
+          l1_key_id: l1_key_id,
+          l2_key_id: l2_key_id
+        )
+
+        response = dcerpc_request(
+          gkdi_get_key_request,
+          auth_level: @auth_level,
+          auth_type: @auth_type
+        )
+        begin
+          gkdi_get_key_response = GkdiGetKeyResponse.read(response)
+        rescue IOError
+          raise RubySMB::Dcerpc::Error::InvalidPacket, 'Error reading CertServerRequestResponse'
+        end
+        unless gkdi_get_key_response.error_status == WindowsError::NTStatus::STATUS_SUCCESS
+          status_code = WindowsError::Win32.find_by_retval(gkdi_get_key_response.error_status.value).first
+          raise RubySMB::Dcerpc::Error::GkdiError.new(
+            "Error returned with gkdi_get_key: #{status_code}",
+            status_code: status_code
+          )
+        end
+
+        GkdiGroupKeyEnvelope.read(gkdi_get_key_response.pbb_out.snapshot.pack('C*'))
+      end
+
+    end
+  end
+end

lib/ruby_smb/dcerpc/gkdi/gkdi_ffc_dh_key.rb

@@ -0,0 +1,17 @@
+module RubySMB
+  module Dcerpc
+    module Gkdi
+
+      # [2.2.3.1 FFC DH Key](https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-gkdi/f8770f01-036d-4bf6-a4cf-1bd0e3913404)
+      class GkdiFfcDhKey < BinData::Record
+        endian :little
+
+        uint8_array :magic, initial_length: 4, initial_value: [ 0x44, 0x48, 0x50, 0x42 ]
+        uint32      :key_length
+        uint8_array :field_order, initial_length: :key_length
+        uint8_array :generator, initial_length: :key_length
+        uint8_array :public_key, initial_length: :key_length
+      end
+    end
+  end
+end

lib/ruby_smb/dcerpc/gkdi/gkdi_ffc_dh_parameters.rb

@@ -0,0 +1,17 @@
+module RubySMB
+  module Dcerpc
+    module Gkdi
+
+      # [2.2.2 FFC DH Parameters](https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-gkdi/e15ae269-ee21-446a-a480-de3ea243db5f)
+      class GkdiFfcDhParameters < BinData::Record
+        endian :little
+
+        uint32      :parameters_length, initial_value: -> { (key_length * 2) + offset_of(generator) }
+        uint8_array :magic, initial_length: 4, initial_value: [ 0x44, 0x48, 0x50, 0x4d ]
+        uint32      :key_length
+        uint8_array :field_order, initial_length: :key_length
+        uint8_array :generator, initial_length: :key_length
+      end
+    end
+  end
+end

lib/ruby_smb/dcerpc/gkdi/gkdi_get_key_request.rb

@@ -0,0 +1,26 @@
+module RubySMB
+  module Dcerpc
+    module Gkdi
+
+      # [3.1.4.1 GetKey (Opnum 0)](https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-gkdi/4cac87a3-521e-4918-a272-240f8fabed39)
+      class GkdiGetKeyRequest < BinData::Record
+        attr_reader :opnum
+
+        endian :little
+
+        ndr_uint32     :cb_target_sd
+        ndr_conf_array :pb_target_sd, type: :ndr_uint8
+        uuid_ptr       :p_root_key_id
+        ndr_int32      :l0_key_id
+        ndr_int32      :l1_key_id
+        ndr_int32      :l2_key_id
+
+        def initialize_instance
+          super
+          @opnum = GKDI_GET_KEY
+        end
+      end
+
+    end
+  end
+end

lib/ruby_smb/dcerpc/gkdi/gkdi_get_key_response.rb

@@ -0,0 +1,23 @@
+module RubySMB
+  module Dcerpc
+    module Gkdi
+
+      # [3.1.4.1 GetKey (Opnum 0)](https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-gkdi/4cac87a3-521e-4918-a272-240f8fabed39)
+      class GkdiGetKeyResponse < BinData::Record
+        attr_reader :opnum
+
+        endian :little
+
+        ndr_uint32              :pcb_out
+        ndr_byte_conf_array_ptr :pbb_out
+        ndr_uint32              :error_status
+
+        def initialize_instance
+          super
+          @opnum = GKDI_GET_KEY
+        end
+      end
+
+    end
+  end
+end

lib/ruby_smb/dcerpc/gkdi/gkdi_group_key_envelope.rb

@@ -0,0 +1,51 @@
+module RubySMB
+  module Dcerpc
+    module Gkdi
+
+      # [2.2.4 Group Key Envelope](https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-gkdi/192c061c-e740-4aa0-ab1d-6954fb3e58f7)
+      class GkdiGroupKeyEnvelope < BinData::Record
+        endian :little
+
+        uint32      :version
+        uint8_array :magic, initial_length: 4, initial_value: [ 0x4b, 0x44, 0x53, 0x5b ]
+        uint32      :dw_flags
+        uint32      :l0_index
+        uint32      :l1_index
+        uint32      :l2_index
+        uuid        :root_key_identifier
+        uint32      :cb_kdf_algorithm
+        uint32      :cb_kdf_parameters, initial_value: -> { kdf_parameters.length }
+        uint32      :cb_secret_agreement_algorithm
+        uint32      :cb_secret_agreement_parameters
+        uint32      :private_key_length
+        uint32      :public_key_length
+        uint32      :cb_l1_key
+        uint32      :cb_l2_key
+        uint32      :cb_domain_name
+        uint32      :cb_forest_name
+        stringz16   :kdf_algorithm
+        struct      :kdf_parameters, only_if: -> { cb_kdf_parameters > 0 } do
+          uint8_array :block0, initial_length: 8, initial_value: [ 0, 0, 0, 0, 1, 0, 0, 0 ]
+          uint32      :length_of_hash_name, initial_value: -> { hash_algorithm_name.length }
+          uint8_array :block1, initial_length: 4, initial_value: [ 0, 0, 0, 0 ]
+          stringz16   :hash_algorithm_name
+        end
+        stringz16   :secret_agreement_algorithm
+        uint8_array :secret_agreement_parameters, initial_length: :cb_secret_agreement_parameters
+        stringz16   :domain_name
+        stringz16   :forest_name
+        uint8_array :l1_key, initial_length: 64, only_if: -> { cb_l1_key != 0 }
+        uint8_array :l2_key, initial_length: :l2_key_length, only_if: -> { cb_l2_key != 0 }
+
+        private
+
+        def l2_key_length
+          return 0 if cb_l2_key == 0
+          return 64 if (dw_flags & (1 << 31)) == 0
+
+          public_key_length
+        end
+      end
+    end
+  end
+end

lib/ruby_smb/dcerpc/request.rb

@@ -124,6 +124,9 @@ class Request < BinData::Record
           lsar_close_handle_request              Lsarpc::LSAR_CLOSE_HANDLE
           lsar_lookup_sids_request               Lsarpc::LSAR_LOOKUP_SIDS
         end
+        choice 'Gkdi', selection: -> { opnum } do
+          gkdi_get_key_request Gkdi::GKDI_GET_KEY
+        end
         string :default
       end