Moved sequence numbers back to transport.

Author: tyranid

NtApiDotNet/Win32/Rpc/Transport/RpcConnectedClientTransport.cs

@@ -74,6 +74,8 @@ protected RpcConnectedClientTransport(ushort max_recv_fragment, ushort max_send_
         private int _current_context_id;
         private ushort _max_recv_fragment;
         private ushort _max_send_fragment;
+        private int _recv_sequence_no;
+        private int _send_senqunce_no;
         private BindTimeFeatureNegotiation? _bind_time_features;
         private bool _transport_bound;
         private Guid _interface_id;
@@ -147,7 +149,7 @@ private Tuple<PDUBase, AuthData> SendReceivePDU(int call_id, PDUBase send_pdu, b
                 RpcUtils.DumpBuffer(true, $"{GetType().Name} Send Buffer", fragment);
                 if (!WriteFragment(fragment))
                     throw new RpcTransportException("Failed to write out PDU buffer.");
-                security_context.SendSequenceNo++;
+                _send_senqunce_no++;
                 if (!receive_pdu)
                     return null;
 
@@ -168,7 +170,7 @@ private Tuple<PDUBase, AuthData> SendReceivePDU(int call_id, PDUBase send_pdu, b
                     throw new RpcTransportException($"Mismatching context ID - {pdu.Item3.ContextId} should be {security_context.ContextId}.");
                 }
 
-                security_context.RecvSequenceNo++;
+                _recv_sequence_no++;
 
                 return Tuple.Create(CheckFault(curr_header.ToPDU(pdu.Item2)), pdu.Item3);
             }
@@ -255,7 +257,7 @@ private byte[] SendReceiveRequestPDU(int proc_num, Guid objuuid, byte[] stub_dat
                         }
 
                         header = request_pdu.ToArray(pdu_header, stub_fragment.Length + AuthData.PDU_AUTH_DATA_HEADER_SIZE, auth_data_length);
-                        auth_data = security_context.ProtectPDU(header, ref stub_fragment, auth_data_padding);
+                        auth_data = security_context.ProtectPDU(header, ref stub_fragment, auth_data_padding, _send_senqunce_no);
                     }
 
                     MemoryStream send_stm = new MemoryStream();
@@ -268,7 +270,7 @@ private byte[] SendReceiveRequestPDU(int proc_num, Guid objuuid, byte[] stub_dat
                     RpcUtils.DumpBuffer(true, name, fragment);
                     if (!WriteFragment(fragment))
                         throw new RpcTransportException("Failed to write out PDU buffer.");
-                    security_context.SendSequenceNo++;
+                    _send_senqunce_no++;
                 }
 
                 MemoryStream recv_stm = new MemoryStream();
@@ -293,8 +295,8 @@ private byte[] SendReceiveRequestPDU(int proc_num, Guid objuuid, byte[] stub_dat
                     if (recv_pdu is PDUResponse resp_pdu)
                     {
                         byte[] resp_stub_data = auth_required ? security_context.UnprotectPDU(resp_pdu.ToArray(curr_header), 
-                            resp_pdu.StubData, auth_data) : resp_pdu.StubData;
-                        security_context.RecvSequenceNo++;
+                            resp_pdu.StubData, auth_data, _recv_sequence_no) : resp_pdu.StubData;
+                        _recv_sequence_no++;
                         recv_stm.Write(resp_stub_data, 0, resp_stub_data.Length);
                     }
                     else

NtApiDotNet/Win32/Rpc/Transport/RpcTransportSecurityContext.cs

@@ -48,14 +48,6 @@ public sealed class RpcTransportSecurityContext
         /// The authentication level.
         /// </summary>
         public RpcAuthenticationLevel AuthenticationLevel => TransportSecurity.AuthenticationLevel;
-        /// <summary>
-        /// The current send sequence no.
-        /// </summary>
-        public int SendSequenceNo { get; internal set; }
-        /// <summary>
-        /// The current receive sequence no.
-        /// </summary>
-        public int RecvSequenceNo { get; internal set; }
 
         internal bool Authenticated => AuthContext?.Done ?? false;
         internal bool NeedAuthData => TransportSecurity.AuthenticationLevel == RpcAuthenticationLevel.PacketIntegrity ||
@@ -96,7 +88,7 @@ internal RpcTransportSecurityContext(IRpcClientTransport client_transport,
             AuthContext = transport_security.CreateClientContext();
         }
 
-        internal byte[] ProtectPDU(byte[] header, ref byte[] stub_data, int auth_padding_length)
+        internal byte[] ProtectPDU(byte[] header, ref byte[] stub_data, int auth_padding_length, int send_sequence_no)
         {
             List<SecurityBuffer> buffers = new List<SecurityBuffer>();
             buffers.Add(new SecurityBufferInOut(SecurityBufferType.Data | SecurityBufferType.ReadOnly, header));
@@ -108,11 +100,11 @@ internal byte[] ProtectPDU(byte[] header, ref byte[] stub_data, int auth_padding
             byte[] signature;
             if (TransportSecurity.AuthenticationLevel == RpcAuthenticationLevel.PacketIntegrity)
             {
-                signature = AuthContext.MakeSignature(buffers, SendSequenceNo);
+                signature = AuthContext.MakeSignature(buffers, send_sequence_no);
             }
             else
             {
-                signature = AuthContext.EncryptMessage(buffers, SecurityQualityOfProtectionFlags.None, SendSequenceNo);
+                signature = AuthContext.EncryptMessage(buffers, SecurityQualityOfProtectionFlags.None, send_sequence_no);
                 stub_data = stub_data_buffer.ToArray();
                 RpcUtils.DumpBuffer(true, "Send Encrypted Data", stub_data);
             }
@@ -121,7 +113,7 @@ internal byte[] ProtectPDU(byte[] header, ref byte[] stub_data, int auth_padding
             return AuthData.ToArray(TransportSecurity, auth_padding_length, ContextId, signature);
         }
 
-        internal byte[] UnprotectPDU(byte[] header, byte[] stub_data, AuthData auth_data)
+        internal byte[] UnprotectPDU(byte[] header, byte[] stub_data, AuthData auth_data, int recv_sequence_no)
         {
             List<SecurityBuffer> buffers = new List<SecurityBuffer>();
             buffers.Add(new SecurityBufferInOut(SecurityBufferType.Data | SecurityBufferType.ReadOnly, header));
@@ -137,14 +129,14 @@ internal byte[] UnprotectPDU(byte[] header, byte[] stub_data, AuthData auth_data
 
             if (TransportSecurity.AuthenticationLevel == RpcAuthenticationLevel.PacketIntegrity)
             {
-                if (!AuthContext.VerifySignature(buffers, signature, RecvSequenceNo))
+                if (!AuthContext.VerifySignature(buffers, signature, recv_sequence_no))
                 {
                     throw new RpcTransportException("Invalid response PDU signature.");
                 }
             }
             else
             {
-                AuthContext.DecryptMessage(buffers, signature, RecvSequenceNo);
+                AuthContext.DecryptMessage(buffers, signature, recv_sequence_no);
                 stub_data = stub_data_buffer.ToArray();
             }