Add inital support for padata

lib/rex/proto/kerberos/model/field/pre_auth_data.rb

@@ -6,6 +6,45 @@ module Rex
           class PreAuthData < Element
             attr_accessor :type
             attr_accessor :value
+
+            def decode(input)
+              case input
+              when String
+                decode_string(input)
+              when OpenSSL::ASN1::Sequence
+                decode_asn1(input)
+              else
+                raise ::RuntimeError, 'Failed to decode Principal Name, invalid input'
+              end
+
+              self
+            end
+
+            def encode
+              raise ::RuntimeError, 'PreAuthData encoding unsupported'
+            end
+
+            private
+
+            def decode_string(input)
+              asn1 = OpenSSL::ASN1.decode(input)
+
+              decode_asn1(asn1)
+            end
+
+            def decode_asn1(input)
+              seq_values = input.value
+              self.type  = decode_asn1_type(seq_values[0])
+              self.value = decode_asn1_value(seq_values[1])
+            end
+
+            def decode_asn1_type(input)
+              input.value[0].value.to_i
+            end
+
+            def decode_asn1_value(input)
+              input.value[0].value
+            end
           end
         end
       end

spec/lib/rex/proto/kerberos/model/field/pre_auth_data_spec.rb

@@ -9,12 +9,58 @@ describe Rex::Proto::Kerberos::Model::Field::PreAuthData do
     described_class.new
   end
 
-  let(:timestamp_pac_sample) do
+  let(:timestamp_sample) do
     "\x30\x48\xa1\x03\x02\x01\x02\xa2\x41\x04\x3f\x30\x3d\xa0\x03\x02" +
     "\x01\x17\xa2\x36\x04\x34\x60\xae\x53\xa5\x0b\x56\x2e\x46\x61\xd9" +
     "\xd6\x89\x98\xfc\x79\x9d\x45\x73\x7d\x0d\x8a\x78\x84\x4d\xd7\x7c" +
     "\xc6\x50\x08\x8d\xab\x22\x79\xc3\x8d\xd3\xaf\x9f\x5e\xb7\xb8\x9b" +
-    "\x57\xc5\xc9\xc5\xea\x90\x89\xc3\x63\x58\x30\x11\xa1\x04\x02\x02" +
+    "\x57\xc5\xc9\xc5\xea\x90\x89\xc3\x63\x58"
+  end
+
+  let(:pac_sample) do
+    "\x30\x11\xa1\x04\x02\x02" +
     "\x00\x80\xa2\x09\x04\x07\x30\x05\xa0\x03\x01\x01\x00"
   end
+
+  describe ".new" do
+    it "returns a Rex::Proto::Kerberos::Model::Field::PreAuthData" do
+      expect(pre_auth_data).to be_a(Rex::Proto::Kerberos::Model::Field::PreAuthData)
+    end
+  end
+
+  describe "#decode" do
+    context "when PAC-ENC-TIMESTAMP" do
+      it "returns the decoded Rex::Proto::Kerberos::Model::Field::PreAuthData" do
+        expect(pre_auth_data.decode(timestamp_sample)).to eq(pre_auth_data)
+      end
+
+      it "decodes type" do
+        pre_auth_data.decode(timestamp_sample)
+        expect(pre_auth_data.type).to eq(2)
+      end
+
+      it "decodes value" do
+        pre_auth_data.decode(timestamp_sample)
+        expect(pre_auth_data.value.length).to eq(63)
+      end
+    end
+
+    context "when PA-PAC-REQUEST" do
+      it "returns the decoded Rex::Proto::Kerberos::Model::Field::PreAuthData" do
+        expect(pre_auth_data.decode(pac_sample)).to eq(pre_auth_data)
+      end
+
+      it "decodes type" do
+        pre_auth_data.decode(pac_sample)
+        expect(pre_auth_data.type).to eq(128)
+      end
+
+      it "decodes value" do
+        pre_auth_data.decode(pac_sample)
+        expect(pre_auth_data.value.length).to eq(7)
+      end
+
+    end
+  end
+
 end