i will make patch with vb.net

but i dont know how read or write sepecific bytes

ex:

 

&HF7, &HD8, &H1B, &HC0, &H40, &H89, &H45, &HE0

 

i want to change  &H1B to &H33 and &H40 to &H90 but skip other byte

 

( Skip(HF7),Skip(HD8), patch(H1B),Skip(HC0), Patch(H40), skip skip skip) like in uPPP

 

search : F7 D8 1B C0 40 89 45 E0

Replace ..     ..  33  ..   90  ..    .. ..

Private Shared ReadOnly PatchFind As Byte() = {&HF7, &HD8, &H1B, &HC0, &H40, &H89, &H45, &HE0}

    Private Shared ReadOnly PatchReplace As Byte() = {&HF7, &HD8, &H33, &HC0, &H90, &H89, &H45, &HE0}

    <MethodImpl(MethodImplOptions.AggressiveInlining)>

    Private Shared Function DetectPatch(sequence As Byte(), position As Integer) As Boolean

        If position + PatchFind.Length > sequence.Length Then

            Return False

        End If

        For p As Integer = 0 To PatchFind.Length - 1

            If PatchFind(p) <> sequence(position + p) Then

                Return False

            End If

        Next

        Return True

    End Function
    Private Shared Sub PatchFile(originalFile As String, patchedFile As String)

        ' Ensure target directory exists.

        Dim targetDirectory = Path.GetDirectoryName(patchedFile)

        If targetDirectory Is Nothing Then

            Return

        End If

        Directory.CreateDirectory(targetDirectory)
        ' Read file bytes.

        Dim fileContent As Byte() = File.ReadAllBytes(originalFile)
        ' Detect and patch file.

        For p As Integer = 0 To fileContent.Length - 1

            If Not DetectPatch(fileContent, p) Then

                Continue For

            End If
            For w As Integer = 0 To PatchFind.Length - 1
                fileContent(p + w) = PatchReplace(w)

            Next

        Next
        ' Save it to another location.

        File.WriteAllBytes(patchedFile, fileContent)

    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        PatchFile("C:\App.exe", "C:\App_patch.exe")

    End Sub

thx before

 

sorry my english is bad

Edited February 25, 201510 yr by andrextrap

Look to my R6002 tool or ExeCryptor CRC patcher.