Boolean FilterCallback(IntPtr sendDataPtr, IntPtr replyDataPtr)
{
Boolean ret = true;
try
{
FilterAPI.MessageSendData messageSend = (FilterAPI.MessageSendData)Marshal.PtrToStructure(sendDataPtr, typeof(FilterAPI.MessageSendData));
if (FilterAPI.MESSAGE_SEND_VERIFICATION_NUMBER != messageSend.VerificationNumber)
{
MessageBoxHelper.PrepToCenterMessageBoxOnForm(this);
MessageBox.Show("Received message corrupted.Please check if the MessageSendData structure is correct.");
EventManager.WriteMessage(139, "FilterCallback", EventLevel.Error, "Received message corrupted.Please check if the MessageSendData structure is correct.");
return(false);
}
EventManager.WriteMessage(149, "FilterCallback", EventLevel.Verbose, "Received message Id#" + messageSend.MessageId + " type:" + messageSend.MessageType
+ " CreateOptions:" + messageSend.CreateOptions.ToString("X") + " infoClass:" + messageSend.InfoClass + " fileName:" + messageSend.FileName);
filterMessage.AddMessage(messageSend);
FileProtectorUnitTest.FileIOEventHandler(messageSend);
if (replyDataPtr.ToInt64() != 0)
{
FilterAPI.MessageReplyData messageReply = (FilterAPI.MessageReplyData)Marshal.PtrToStructure(replyDataPtr, typeof(FilterAPI.MessageReplyData));
//if (messageSend.MessageType == (uint)FilterAPI.FilterCommand.FILTER_SEND_PROCESS_TERMINATION_INFO)
//{
// //the process termination callback, you can get the notification if you register the callback setting of the process filter.
//}
if (messageSend.MessageType == (uint)FilterAPI.FilterCommand.FILTER_SEND_PROCESS_CREATION_INFO)
{
//this is new process creation, you can block it here by returning the STATUS_ACCESS_DENIED, below is the process information
FilterAPI.PROCESS_INFO processInfo = (FilterAPI.PROCESS_INFO)Marshal.PtrToStructure(sendDataPtr, typeof(FilterAPI.PROCESS_INFO));
messageReply.ReturnStatus = processInfo.Status;
Marshal.StructureToPtr(messageReply, replyDataPtr, true);
}
else if (messageSend.MessageType == (uint)FilterAPI.FilterCommand.FILTER_REQUEST_ENCRYPTION_IV_AND_KEY)
{
//this is encryption filter rule with boolean config "REQUEST_ENCRYPT_KEY_AND_IV_FROM_SERVICE" enabled.
//the filter driver request the IV and key to open or create the encrypted file.
//if you want to deny the file open or creation, you set the value as below:
//messageReply.ReturnStatus = (uint)FilterAPI.NTSTATUS.STATUS_ACCESS_DENIED;
//messageReply.FilterStatus = (uint)FilterAPI.FilterStatus.FILTER_COMPLETE_PRE_OPERATION;
EventManager.WriteMessage(200, "filtercallback", EventLevel.Verbose, messageSend.FileName + " FILTER_REQUEST_ENCRYPTION_IV_AND_KEY");
//Here we return the test iv and key to the filter driver, you need to replace with you own iv and key in your code.
AESDataBuffer aesData = new AESDataBuffer();
aesData.AccessFlags = FilterAPI.ALLOW_MAX_RIGHT_ACCESS;
aesData.IV = FilterAPI.DEFAULT_IV_TAG;
aesData.IVLength = (uint)aesData.IV.Length;
aesData.EncryptionKey = Utils.GetKeyByPassPhrase(DigitalRightControl.PassPhrase);
aesData.EncryptionKeyLength = (uint)aesData.EncryptionKey.Length;
byte[] aesDataArray = DigitalRightControl.ConvertAESDataToByteArray(aesData);
messageReply.DataBufferLength = (uint)aesDataArray.Length;
Array.Copy(aesDataArray, messageReply.DataBuffer, aesDataArray.Length);
messageReply.ReturnStatus = (uint)FilterAPI.NTSTATUS.STATUS_SUCCESS;
}
else if (messageSend.MessageType == (uint)FilterAPI.FilterCommand.FILTER_REQUEST_ENCRYPTION_IV_AND_KEY_AND_TAGDATA)
{
//this is encryption filter rule with boolean config "REQUEST_ENCRYPT_KEY_IV_AND_TAGDATA_FROM_SERVICE" enabled.
//the filter driver request the IV and key to open or create the encrypted file.
//if you want to deny the file open or creation, you set the value as below:
//messageReply.ReturnStatus = (uint)FilterAPI.NTSTATUS.STATUS_ACCESS_DENIED;
//messageReply.FilterStatus = (uint)FilterAPI.FilterStatus.FILTER_COMPLETE_PRE_OPERATION;
if (messageSend.DataBufferLength > 0)
{
//this is the tag data which attached to the encrypted file .
string tagDataStr = Encoding.Unicode.GetString(messageSend.DataBuffer);
EventManager.WriteMessage(235, "filtercallback", EventLevel.Verbose, "EncryptedFile:" + messageSend.FileName + ",tagData:" + tagDataStr);
}
//Here we return the test iv ,key and tag data to the filter driver, you need to replace with you own iv and key in your code.
AESDataBuffer aesData = new AESDataBuffer();
aesData.AccessFlags = FilterAPI.ALLOW_MAX_RIGHT_ACCESS;
aesData.IV = FilterAPI.DEFAULT_IV_TAG;
aesData.IVLength = (uint)aesData.IV.Length;
aesData.EncryptionKey = Utils.GetKeyByPassPhrase(DigitalRightControl.PassPhrase);
aesData.EncryptionKeyLength = (uint)aesData.EncryptionKey.Length;
aesData.TagData = Encoding.Unicode.GetBytes("TagData:" + messageSend.FileName);
aesData.TagDataLength = (uint)aesData.TagData.Length;
byte[] aesDataArray = DigitalRightControl.ConvertAESDataToByteArray(aesData);
messageReply.DataBufferLength = (uint)aesDataArray.Length;
Array.Copy(aesDataArray, messageReply.DataBuffer, aesDataArray.Length);
messageReply.ReturnStatus = (uint)FilterAPI.NTSTATUS.STATUS_SUCCESS;
}
else
{
//this is for control filter driver when the pre-IO was registered.
//here you can control the IO behaviour and modify the data.
if (!FileProtectorUnitTest.UnitTestCallbackHandler(messageSend) || !FilterService.AuthorizeFileAccess(messageSend, ref messageReply))
{
//to comple the PRE_IO
messageReply.ReturnStatus = (uint)FilterAPI.NTSTATUS.STATUS_ACCESS_DENIED;
messageReply.FilterStatus = (uint)FilterAPI.FilterStatus.FILTER_COMPLETE_PRE_OPERATION;
EventManager.WriteMessage(160, "FilterCallback", EventLevel.Error, "Return error for I/O request:" + ((FilterAPI.MessageType)messageSend.MessageType).ToString() +
",fileName:" + messageSend.FileName);
}
else
{
messageReply.MessageId = messageSend.MessageId;
messageReply.MessageType = messageSend.MessageType;
messageReply.ReturnStatus = (uint)FilterAPI.NTSTATUS.STATUS_SUCCESS;
}
}
Marshal.StructureToPtr(messageReply, replyDataPtr, true);
}
return(ret);
}
catch (Exception ex)
{
EventManager.WriteMessage(134, "FilterCallback", EventLevel.Error, "filter callback exception." + ex.Message);
return(false);
}
}
static public bool GetFileAccessPermission(ref FilterAPI.MessageSendData messageSend, ref FilterAPI.MessageReplyData messageReply)
{
Boolean retVal = true;
string fileName = messageSend.FileName;
string lastError = string.Empty;
string processName = string.Empty;
string userName = string.Empty;
string encryptKey = string.Empty;
try
{
FilterAPI.DecodeProcessName(messageSend.ProcessId, out processName);
FilterAPI.DecodeUserName(messageSend.Sid, out userName);
//by default the tag data format is "accountName;ivStr"
int tagDataLength = (int)messageSend.DataBufferLength;
byte[] tagData = messageSend.DataBuffer;
Array.Resize(ref tagData, tagDataLength);
string tagStr = UnicodeEncoding.Unicode.GetString(tagData);
int index = tagStr.IndexOf(";");
byte[] iv = tagData;
if (index > 0)
{
string serverAccount = tagStr.Substring(0, index);
string ivStr = tagStr.Substring(index + 1);
iv = Utils.ConvertHexStrToByteArray(ivStr);
}
uint accessFlag = 0;
retVal = IsFileAccessAuthorized(fileName,
userName,
processName,
tagStr,
ref encryptKey,
ref accessFlag,
ref lastError);
if (retVal && !string.IsNullOrEmpty(encryptKey))
{
byte[] keyArray = Utils.ConvertHexStrToByteArray(encryptKey);
//write the iv and key to the reply data buffer with format FilterAPI.AESDataBuffer
AESDataBuffer aesData = new AESDataBuffer();
if (messageSend.MessageType == (uint)FilterAPI.FilterCommand.FILTER_REQUEST_ENCRYPTION_IV_AND_KEY_AND_ACCESSFLAG)
{
aesData.AccessFlags = FilterAPI.ALLOW_MAX_RIGHT_ACCESS;
}
else
{
aesData.AccessFlags = FilterAPI.ALLOW_MAX_RIGHT_ACCESS;
}
aesData.IV = iv;
aesData.IVLength = (uint)iv.Length;
aesData.EncryptionKey = keyArray;
aesData.EncryptionKeyLength = (uint)keyArray.Length;
byte[] aesDataArray = DigitalRightControl.ConvertAESDataToByteArray(aesData);
messageReply.DataBufferLength = (uint)aesDataArray.Length;
Array.Copy(aesDataArray, messageReply.DataBuffer, aesDataArray.Length);
messageReply.ReturnStatus = (uint)FilterAPI.NTSTATUS.STATUS_SUCCESS;
}
}
catch (Exception ex)
{
lastError = "GetFileAccessPermission exception." + ex.Message;
EventManager.WriteMessage(340, "GetFileAccessPermission", EventLevel.Error, lastError);
retVal = false;
}
if (!retVal)
{
byte[] errorBuffer = UnicodeEncoding.Unicode.GetBytes(lastError);
Array.Copy(errorBuffer, messageSend.DataBuffer, errorBuffer.Length);
messageSend.DataBufferLength = (uint)errorBuffer.Length;
}
return(retVal);
}
