Merge pull request #70 from thekuwayama/ech__12

[ech] 12. feat: ECHHelloRetryRequest
thekuwayama · Dec 18, 2023 · 853155a · 853155a
2 parents beda780 + bf1903e
commit 853155a
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Showing 5 changed files with 58 additions and 9 deletions.
diff --git a/lib/tttls1.3/message/extension/alpn.rb b/lib/tttls1.3/message/extension/alpn.rb
@@ -19,18 +19,17 @@ class Alpn
         # https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml#alpn-protocol-ids
         def initialize(protocol_name_list)
           @extension_type \
-          = ExtensionType::APPLICATION_LAYER_PROTOCOL_NEGOTIATION
+            = ExtensionType::APPLICATION_LAYER_PROTOCOL_NEGOTIATION
           @protocol_name_list = protocol_name_list || []
           raise Error::ErrorAlerts, :internal_error \
             if @protocol_name_list.empty?
         end
 
         # @return [String]
         def serialize
-          binary = @protocol_name_list
-                   .map(&:prefix_uint8_length)
-                   .join
-                   .prefix_uint16_length
+          binary = @protocol_name_list.map(&:prefix_uint8_length)
+                                      .join
+                                      .prefix_uint16_length
 
           @extension_type + binary.prefix_uint16_length
         end

diff --git a/lib/tttls1.3/message/extension/ech.rb b/lib/tttls1.3/message/extension/ech.rb
@@ -181,6 +181,7 @@ def initialize(retry_configs)
           @retry_configs = retry_configs
         end
 
+        # @return [String]
         def serialize
           @extension_type + @retry_configs.map(&:encode)
                                           .join
@@ -203,6 +204,38 @@ def self.deserialize(binary)
           )
         end
       end
+
+      # NOTE:
+      #     struct {
+      #         opaque confirmation[8];
+      #     } ECHHelloRetryRequest;
+      class ECHHelloRetryRequest
+        attr_accessor :extension_type
+        attr_accessor :confirmation
+
+        # @param confirmation [String]
+        def initialize(confirmation)
+          @extension_type = ExtensionType::ENCRYPTED_CLIENT_HELLO
+          @confirmation = confirmation
+        end
+
+        # @return [String]
+        def serialize
+          @extension_type + @confirmation.prefix_uint16_length
+        end
+
+        # @param binary [String]
+        #
+        # @raise [TTTLS13::Error::ErrorAlerts]
+        #
+        # @return [TTTLS13::Message::Extensions::ECHHelloRetryRequest]
+        def self.deserialize(binary)
+          raise Error::ErrorAlerts, :internal_error \
+            if binary.nil? || binary.length != 8
+
+          ECHHelloRetryRequest.new(binary)
+        end
+      end
     end
   end
 end
diff --git a/lib/tttls1.3/message/extensions.rb b/lib/tttls1.3/message/extensions.rb
@@ -163,12 +163,13 @@ def deserialize_extension(binary, extension_type, msg_type)
           when ExtensionType::KEY_SHARE
             Extension::KeyShare.deserialize(binary, msg_type)
           when ExtensionType::ENCRYPTED_CLIENT_HELLO
-            if msg_type == HandshakeType::CLIENT_HELLO
+            case msg_type
+            when HandshakeType::CLIENT_HELLO
               Extension::ECHClientHello.deserialize(binary)
-            elsif msg_type == HandshakeType::ENCRYPTED_EXTENSIONS
+            when HandshakeType::ENCRYPTED_EXTENSIONS
               Extension::ECHEncryptedExtensions.deserialize(binary)
-            # elsif msg_type == HandshakeType::SERVER_HELLO
-            #   Extension::ECHHelloRetryRequest.deserialize(binary)
+            when HandshakeType::SERVER_HELLO
+              Extension::ECHHelloRetryRequest.deserialize(binary)
             else
               Extension::UnknownExtension.deserialize(binary, extension_type)
             end

diff --git a/spec/ech_spec.rb b/spec/ech_spec.rb
@@ -66,4 +66,16 @@
       expect(extension.retry_configs.first.is_a?(ECHConfig)).to be_truthy
     end
   end
+
+  context 'valid ECHHelloRetryRequest binary' do
+    let(:extension) do
+      ECHHelloRetryRequest.deserialize(TESTBINARY_ECH_HRR)
+    end
+
+    it 'should generate valid object' do
+      expect(extension.extension_type)
+        .to eq ExtensionType::ENCRYPTED_CLIENT_HELLO
+      expect(extension.confirmation).to eq "\x00" * 8
+    end
+  end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
@@ -241,6 +241,10 @@ def read(len = @buffer.length)
   09 6c 6f 63 61 6c 68 6f     73 74 00 00
 BIN
 
+TESTBINARY_ECH_HRR = <<BIN.split.map(&:hex).map(&:chr).join
+  00 00 00 00 00 00 00 00
+BIN
+
 # https://tools.ietf.org/html/rfc8448#section-3
 # 3.  Simple 1-RTT Handshake
 TESTBINARY_CLIENT_HELLO = <<BIN.split.map(&:hex).map(&:chr).join