msiReadStreamInteger Archives

Somebody over at ITNinja recently asked how they could run an executable stored in the binary table, from a VBScript Custom Action. Here’s an example I knocked up which describes how to extract an EXE from the binary table and run it from a VBScript Custom Action. I basically streamed notepad.exe into the binary table, and gave it a name of ‘notepad’. In this Custom Action, I extract it to the %temp% folder and run it from there. Note that there is no cleanup of the extraction afterwards. Also note that because this uses the Session object, it can only be executed in the Immediate context. So more consideration would be required (and probably a separate Custom Action) to execute the extracted EXE in a deferred context.

Dim oFSO : Set oFSO = CreateObject("Scripting.FileSystemObject")

Dim tempFolder : tempFolder = oFSO.GetSpecialFolder(2) 
Dim outputFile : outputFile = tempFolder & "\notepad.exe"

extractFromBinary "notepad", outputFile

If oFSO.fileExists(outputFile) Then 
    Dim objShell : Set objShell = CreateObject("WScript.Shell") 
    objShell.Run (outputFile) 
    Set objShell = Nothing
End If

Function extractFromBinary(ByVal binaryName, ByVal binaryOutputFile)

    Const msiReadStreamInteger = 0 
    Const msiReadStreamBytes = 1 
    Const msiReadStreamAnsi = 2  
    Const msiReadStreamDirect = 3

    Dim binaryView : Set binaryView = Session.Database.OpenView("SELECT * FROM Binary WHERE Name = '" & binaryName & "'")  
    binaryView.Execute

    Dim binaryRecord : Set binaryRecord = binaryView.Fetch  
    Dim binaryData : binaryData = binaryRecord.ReadStream(2, binaryRecord.DataSize(2), msiReadStreamAnsi)  
    Set binaryRecord = Nothing  
    Dim binaryStream : Set binaryStream = oFSO.CreateTextFile(binaryOutputFile, True)  
    binaryStream.Write binaryData  
    binaryStream.Close 
    Set binaryStream = Nothing
  
End Function

Set oFSO = Nothing

Below is an updated version that extracts from the binary table using msiReadStreamDirect (as a binary string), converts the string to binary and outputs it using ADODB.Stream. It may resolve locale-specific issues with the aforementioned approach.

Dim oFSO : Set oFSO = CreateObject("Scripting.FileSystemObject")

Dim tempFolder : tempFolder = oFSO.GetSpecialFolder(2) 
Dim outputFile : outputFile = tempFolder & "\notepad.exe"

extractFromBinary "notepad", outputFile

If oFSO.fileExists(outputFile) Then 
    Dim objShell : Set objShell = CreateObject("WScript.Shell") 
    objShell.Run (outputFile) 
    Set objShell = Nothing
End If

Function MultiByteToBinary(MultiByte)
  'obtained from http://www.motobit.com
  'MultiByteToBinary converts multibyte string To real binary data (VT_UI1 | VT_ARRAY)
  'Using recordset
  Dim RS, LMultiByte, Binary
  Const adLongVarBinary = 205
  Set RS = CreateObject("ADODB.Recordset")
  LMultiByte = LenB(MultiByte)
  If LMultiByte>0 Then
    RS.Fields.Append "mBinary", adLongVarBinary, LMultiByte
    RS.Open
    RS.AddNew
      RS("mBinary").AppendChunk MultiByte & ChrB(0)
    RS.Update
    Binary = RS("mBinary").GetChunk(LMultiByte)
  End If
  Set RS = Nothing
  MultiByteToBinary = Binary
End Function

Function SaveBinaryData(FileName, ByteArray)
  Const adTypeBinary = 1
  Const adSaveCreateOverWrite = 2
  
  'Create Stream object
  Dim BinaryStream
  Set BinaryStream = CreateObject("ADODB.Stream")
  
  'Specify stream type - we want To save binary data.
  BinaryStream.Type = adTypeBinary
  
  'Open the stream And write binary data To the object
  BinaryStream.Open
  BinaryStream.Write ByteArray
  
  'Save binary data To disk
  BinaryStream.SaveToFile FileName, adSaveCreateOverWrite

  Set BinaryStream = Nothing
End Function

Function extractFromBinary(ByVal binaryName, ByVal binaryOutputFile)

    Const msiReadStreamInteger = 0 
    Const msiReadStreamBytes = 1 
    Const msiReadStreamAnsi = 2  
    Const msiReadStreamDirect = 3

    Dim binaryView : Set binaryView = Session.Database.OpenView("SELECT * FROM Binary WHERE Name = '" & binaryName & "'")  
    binaryView.Execute

    Dim binaryRecord : Set binaryRecord = binaryView.Fetch  
    Dim binaryData : binaryData = binaryRecord.ReadStream(2, binaryRecord.DataSize(2), msiReadStreamDirect)  
    Set binaryRecord = Nothing  
    
    'convert to string of byte pairs to binary
    binaryData = MultiByteToBinary(binaryData)
    
    'save binary data
    SaveBinaryData binaryOutputFile, binaryData

End Function

Set oFSO = Nothing

Finally, i verified the file imported into the Binary table against the file extracted from the Binary table using this simple command line:
fc.exe /b [full_path_file_1] [full_path_file_2]

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