Minor code refactoring, do not try to process async commands other than CANCEL

SMBLibrary/SMBLibrary.csproj

@@ -200,8 +200,10 @@
     <Compile Include="Server\Shares\ISMBShare.cs" />
     <Compile Include="Server\Shares\NamedPipeShare.cs" />
     <Compile Include="Server\Shares\SMBShareCollection.cs" />
+    <Compile Include="Server\SMB1\CancelHelper.cs" />
     <Compile Include="Server\SMB1\FileStoreResponseHelper.cs" />
     <Compile Include="Server\SMB1\NegotiateHelper.cs" />
+    <Compile Include="Server\SMB1\NotifyChangeHelper.cs" />
     <Compile Include="Server\SMB1\NTCreateHelper.cs" />
     <Compile Include="Server\SMB1\NTTransactHelper.cs" />
     <Compile Include="Server\SMB1\OpenAndXHelper.cs" />
@@ -217,6 +219,8 @@
     <Compile Include="Server\SMB1\TransactionHelper.cs" />
     <Compile Include="Server\SMB1\TransactionSubcommandHelper.cs" />
     <Compile Include="Server\SMB1\TreeConnectHelper.cs" />
+    <Compile Include="Server\SMB2\CancelHelper.cs" />
+    <Compile Include="Server\SMB2\ChangeNotifyHelper.cs" />
     <Compile Include="Server\SMB2\CloseHelper.cs" />
     <Compile Include="Server\SMB2\CreateHelper.cs" />
     <Compile Include="Server\SMB2\IOCtlHelper.cs" />

SMBLibrary/Server/SMB1/CancelHelper.cs

@@ -0,0 +1,20 @@
+/* Copyright (C) 2017 Tal Aloni <tal.aloni.il@gmail.com>. All rights reserved.
+ * 
+ * You can redistribute this program and/or modify it under the terms of
+ * the GNU Lesser Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ */
+using System;
+using System.Collections.Generic;
+using SMBLibrary.SMB1;
+using Utilities;
+
+namespace SMBLibrary.Server.SMB1
+{
+    internal class CancelHelper
+    {
+        internal static void ProcessNTCancelRequest(SMB1Header header, NTCancelRequest request, ISMBShare share, SMB1ConnectionState state)
+        {
+        }
+    }
+}

SMBLibrary/Server/SMB1/NTTransactHelper.cs

@@ -102,9 +102,11 @@ namespace SMBLibrary.Server.SMB1
             }
             else if (subcommand is NTTransactNotifyChangeRequest)
             {
-                // [MS-CIFS] If the server does not support the NT_TRANSACT_NOTIFY_CHANGE subcommand, it can return an
-                // error response with STATUS_NOT_IMPLEMENTED [..] in response to an NT_TRANSACT_NOTIFY_CHANGE Request.
-                header.Status = NTStatus.STATUS_NOT_IMPLEMENTED;
+                NotifyChangeHelper.ProcessNTTransactNotifyChangeRequest(header, maxParameterCount, (NTTransactNotifyChangeRequest)subcommand, share, state);
+                if (header.Status == NTStatus.STATUS_PENDING)
+                {
+                    return new List<SMB1Command>();
+                }
             }
             else if (subcommand is NTTransactQuerySecurityDescriptorRequest)
             {

SMBLibrary/Server/SMB1/NotifyChangeHelper.cs

@@ -0,0 +1,23 @@
+/* Copyright (C) 2017 Tal Aloni <tal.aloni.il@gmail.com>. All rights reserved.
+ * 
+ * You can redistribute this program and/or modify it under the terms of
+ * the GNU Lesser Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ */
+using System;
+using System.Collections.Generic;
+using SMBLibrary.SMB1;
+using Utilities;
+
+namespace SMBLibrary.Server.SMB1
+{
+    internal class NotifyChangeHelper
+    {
+        internal static void ProcessNTTransactNotifyChangeRequest(SMB1Header header, uint maxParameterCount, NTTransactNotifyChangeRequest subcommand, ISMBShare share, SMB1ConnectionState state)
+        {
+            // [MS-CIFS] If the server does not support the NT_TRANSACT_NOTIFY_CHANGE subcommand, it can return an
+            // error response with STATUS_NOT_IMPLEMENTED [..] in response to an NT_TRANSACT_NOTIFY_CHANGE Request.
+            header.Status = NTStatus.STATUS_NOT_IMPLEMENTED;
+        }
+    }
+}

SMBLibrary/Server/SMB2/CancelHelper.cs

@@ -0,0 +1,30 @@
+/* Copyright (C) 2017 Tal Aloni <tal.aloni.il@gmail.com>. All rights reserved.
+ * 
+ * You can redistribute this program and/or modify it under the terms of
+ * the GNU Lesser Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ */
+using System;
+using System.Collections.Generic;
+using SMBLibrary.SMB2;
+using Utilities;
+
+namespace SMBLibrary.Server.SMB2
+{
+    internal class CancelHelper
+    {
+        internal static SMB2Command GetCancelResponse(CancelRequest request, SMB2ConnectionState state)
+        {
+            if (request.Header.IsAsync && request.Header.AsyncID == 0)
+            {
+                ErrorResponse response = new ErrorResponse(request.CommandName, NTStatus.STATUS_CANCELLED);
+                response.Header.IsAsync = true;
+                return response;
+            }
+
+            // [MS-SMB2] If a request is not found [..] no response is sent.
+            // [MS-SMB2] If the target request is not successfully canceled [..] no response is sent.
+            return null;
+        }
+    }
+}

SMBLibrary/Server/SMB2/ChangeNotifyHelper.cs

@@ -0,0 +1,26 @@
+/* Copyright (C) 2017 Tal Aloni <tal.aloni.il@gmail.com>. All rights reserved.
+ * 
+ * You can redistribute this program and/or modify it under the terms of
+ * the GNU Lesser Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ */
+using System;
+using System.Collections.Generic;
+using SMBLibrary.SMB2;
+using Utilities;
+
+namespace SMBLibrary.Server.SMB2
+{
+    internal class ChangeNotifyHelper
+    {
+        internal static SMB2Command GetChangeNotifyInterimResponse(ChangeNotifyRequest request, ISMBShare share, SMB2ConnectionState state)
+        {
+            // [MS-SMB2] If the underlying object store does not support change notifications, the server MUST fail this request with STATUS_NOT_SUPPORTED
+            ErrorResponse response = new ErrorResponse(request.CommandName, NTStatus.STATUS_NOT_SUPPORTED);
+            // Windows 7 / 8 / 10 will infinitely retry sending ChangeNotify requests if the response does not have SMB2_FLAGS_ASYNC_COMMAND set.
+            // Note: NoRemoteChangeNotify can be set in the registry to prevent the client from sending ChangeNotify requests altogether.
+            response.Header.IsAsync = true;
+            return response;
+        }
+    }
+}

SMBLibrary/Server/SMBServer.SMB1.cs

@@ -281,6 +281,13 @@ namespace SMBLibrary.Server
                         NTCreateAndXRequest request = (NTCreateAndXRequest)command;
                         return NTCreateHelper.GetNTCreateResponse(header, request, share, state);
                     }
+                    else if (command is NTCancelRequest)
+                    {
+                        NTCancelRequest request = (NTCancelRequest)command;
+                        CancelHelper.ProcessNTCancelRequest(header, request, share, state);
+                        // [MS-CIFS] The SMB_COM_NT_CANCEL command MUST NOT send a response.
+                        return new List<SMB1Command>();
+                    }
                 }
             }
 

SMBLibrary/Server/SMBServer.SMB2.cs

@@ -113,22 +113,16 @@ namespace SMBLibrary.Server
                     state.RemoveSession(command.Header.SessionID);
                     return new LogoffResponse();
                 }
-                else
+                else if (command.Header.IsAsync)
                 {
-                    // Cancel requests can have an ASYNC header (TreeID will not be present)
+                    // TreeID will not be present in an ASYNC header
                     if (command is CancelRequest)
                     {
-                        if (command.Header.IsAsync && command.Header.AsyncID == 0)
-                        {
-                            ErrorResponse response = new ErrorResponse(command.CommandName, NTStatus.STATUS_CANCELLED);
-                            response.Header.IsAsync = true;
-                            return response;
-                        }
-
-                        // [MS-SMB2] If a request is not found, the server MUST stop processing for this cancel request. No response is sent.
-                        return null;
+                        return CancelHelper.GetCancelResponse((CancelRequest)command, state);
                     }
-
+                }
+                else
+                {
                     ISMBShare share = session.GetConnectedTree(command.Header.TreeID);
                     if (share == null)
                     {
@@ -175,14 +169,13 @@ namespace SMBLibrary.Server
                     {
                         return IOCtlHelper.GetIOCtlResponse((IOCtlRequest)command, share, state);
                     }
+                    else if (command is CancelRequest)
+                    {
+                        return CancelHelper.GetCancelResponse((CancelRequest)command, state);
+                    }
                     else if (command is ChangeNotifyRequest)
                     {
-                        // [MS-SMB2] If the underlying object store does not support change notifications, the server MUST fail this request with STATUS_NOT_SUPPORTED
-                        ErrorResponse response = new ErrorResponse(command.CommandName, NTStatus.STATUS_NOT_SUPPORTED);
-                        // Windows 7 / 8 / 10 will infinitely retry sending ChangeNotify requests if the response does not have SMB2_FLAGS_ASYNC_COMMAND set.
-                        // Note: NoRemoteChangeNotify can be set in the registry to prevent the client from sending ChangeNotify requests altogether.
-                        response.Header.IsAsync = true;
-                        return response;
+                        return ChangeNotifyHelper.GetChangeNotifyInterimResponse((ChangeNotifyRequest)command, share, state);
                     }
                 }
             }