vb6内联汇编，调用函数指针，不注册调用com

发布时间：2020-12-17 07:48:00 所属栏目：百科来源：网络整理

导读：vb6执行汇编代码一般是使用CallWindowProc，这个方法有参数限制，内部还会执行一些其它调用再到函数指针，我用它调用com里面的“DllGetClassObject”函数时居然出错了，不知道怎么回事，于是乎寻求其它办法，用vc写个dll调用函数指针挺好用的，可惜多了个dll

vb6执行汇编代码一般是使用CallWindowProc，这个方法有参数限制，内部还会执行一些其它调用再到函数指针，我用它调用com里面的“DllGetClassObject”函数时居然出错了，不知道怎么回事，于是乎寻求其它办法，用vc写个dll调用函数指针挺好用的，可惜多了个dll文件。后来采取修改vb模块内函数代码，用AddressOf获取vb函数地址后，再用VirtualProtect修改权限，这样就可以用CopyMemory把汇编代码复制过来，可谓偷梁换柱啊，以后执行这个vb函数就直接运行汇编代码了，不过ide下没效果，得生成exe文件才行，这样就不好调试了。

在网上看到了一种神奇的方法，手动构造一个类，将汇编代码的运行地址写进vtable，前三个方法是IUnknown接口的方法：

HRESULT QueryInterface([in] IID *riid,[in,out] IUnknown **ppvObject);
long AddRef();
long Release();

后面的方法就随意了，我添加了10个调用函数地址的方法，分别对应0个参数-9个参数的呼叫，而且不区分stdcall和cdecl调用约定，ide状态下也正常。

原贴地址：http://demon.tw/programming/vb6-repick-inline-assembly.html

最初只是想不注册调用com，没想折腾出这些东西来的，这是我改过的代码，欢迎测试

Option Explicit

Private Type CLSID
    d1 As Long
    d2 As Integer
    d3 As Integer
    d4(7) As Byte
End Type

Public Declare Function LoadLibraryW Lib "Kernel32.dll" (ByVal lpFileName As Long) As Long
Public Declare Function GetProcAddress Lib "Kernel32.dll" (ByVal hModule As Long,ByVal lpProcName As String) As Long
Public Declare Function CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (ByVal Destination As Long,ByVal Source As Long,ByVal Length As Long) As Long
Public Declare Function VirtualProtect Lib "kernel32" (ByVal lpAddress As Any,ByVal dwSize As Long,ByVal flNewProtect As Long,lpflOldProtect As Long) As Long
Public Declare Function CLSIDFromString Lib "ole32.dll" (ByVal lpsz As Long,pclsid As Long) As Long
Declare Function CallWindowProcA Lib "user32.dll" (ByVal lpPrevWndFunc As Long,ByVal hWnd As Long,ByVal Msg As Long,ByVal wParam As Long,ByVal lParam As Long) As Long

Dim m_cthis As Long
Dim m_vtab(20) As Long
Dim m_acode(100) As Long
Dim m_ICallFunAddr As ICallFunAddr

'member索引从0开始，IUnknown3个成员函数，IDispatch4个成员函数，IClassFactory.CreateInstance在3号位置
Public Function GetClassMemberAddr(ByVal cthis As Long,ByVal member As Long) As Long
    Dim vtab As Long
    Dim fun As Long
    CopyMemory VarPtr(vtab),ByVal cthis,4
    CopyMemory VarPtr(fun),ByVal vtab + member * 4,4
    GetClassMemberAddr = fun
End Function

Public Function Dll_GetClassObject(dllname As String,sclsid As String,siid As String) As Object
Dim dll As Long
Dim hr As Long
Dim clsid_icf As CLSID
Dim clsid_cls As CLSID
Dim clsid_iid As CLSID
Dim icf As IClassFactory
Dim funDllGetClassObject As Long
Dim funCreateInstance As Long
Dim funRelease As Long
Dim calladdr As ICallFunAddr
    Set calladdr = MakeCallFunAddrObj
    dll = LoadLibraryW(StrPtr(dllname))
    If dll > 0 Then
        funDllGetClassObject = GetProcAddress(dll,"DllGetClassObject")
        If funDllGetClassObject > 0 Then
            hr = CLSIDFromString(StrPtr("{00000001-0000-0000-C000-000000000046}"),clsid_icf.d1)
            hr = CLSIDFromString(StrPtr(sclsid),clsid_cls.d1)
            hr = CLSIDFromString(StrPtr(siid),clsid_iid.d1)
            'hr = CallWindowProcA(funDllGetClassObject,VarPtr(clsid_cls.d1),VarPtr(clsid_icf.d1),VarPtr(icf),0)
            hr = calladdr.arg3(funDllGetClassObject,VarPtr(icf))
            hr = icf.CreateInstance(0,VarPtr(clsid_iid.d1),Dll_GetClassObject)
            'funCreateInstance = GetClassMemberAddr(icf,3)
            'funRelease = GetClassMemberAddr(icf,2)
            'hr = calladdr.arg4(funCreateInstance,icf,VarPtr(Dll_GetClassObject))
            'hr = calladdr.arg1(funRelease,icf)
            'MsgBox TypeName(obj)
        End If
        'FreeLibrary dll
    Else
        MsgBox "dll加载失败"
    End If
End Function

'以下代码为一个参数的例子
'00401508 >    55            PUSH EBP
'00401509      8BEC          MOV EBP,ESP
'0040150B      FF75 10       PUSH DWORD PTR SS:[EBP+10]
'0040150E      FF55 0C       CALL DWORD PTR SS:[EBP+C]
'00401511      C9            LEAVE
'00401512      C2 0C00       RETN C
'call方式stdcall和cdecl都可以
'在pcode地址处写入汇编代码，argc压入的参数个数，返回汇编长度
Public Function MakeCallFunAddrCode(ByVal pcode As Long,ByVal argc As Long) As Long
    Dim n As Long
    Dim p As Long
    Dim code As Long
    
    p = pcode
    'push ebp
    code = &HEC8B55
    CopyMemory p,VarPtr(code),3
    p = p + 3
    'push arg
    For n = argc To 1 Step -1
        code = (n * 4 + 12) * &H10000 + &H75FF
        CopyMemory p,3
        p = p + 3
    Next
    'call
    code = &HC55FF
    CopyMemory p,3
    p = p + 3
    'leave retn
    code = (argc * 4 + 8) * &H10000 + &HC2C9&
    CopyMemory p,4
    p = p + 4
    'nop
    code = &H90909090
    n = 4 - p Mod 4 '为以后的代码4字节对齐，代码前后都加入nop
    CopyMemory p,n
    MakeCallFunAddrCode = p + n - pcode
End Function

'    function QueryInterface(riid:^GUID; out ppvObj:^^void);
'    function AddRef: UI4;
'    function Release: UI4;
'00401480 >    8B4424 04     MOV EAX,DWORD PTR SS:[ESP+4]
'00401484      8B4C24 0C     MOV ECX,DWORD PTR SS:[ESP+C]
'00401488 >    8901          MOV DWORD PTR DS:[ECX],EAX
'0040148A      33C0          XOR EAX,EAX
'0040148C      C2 0C00       RETN 0C
'0040148F      90            NOP
'00401490      33C0          XOR EAX,EAX
'00401492      40            INC EAX
'00401493      C2 0400       RETN 4
Public Function MakeCallFunAddrObj() As ICallFunAddr
    Dim n As Long
    Dim p As Long
    Dim narg As Long
    Dim nfun As Long
    
    If Not m_ICallFunAddr Is Nothing Then
        Set MakeCallFunAddrObj = m_ICallFunAddr
        Exit Function
    End If
    
    m_cthis = VarPtr(m_vtab(0))
    'QueryInterface
    m_acode(0) = &H424448B
    m_acode(1) = &HC244C8B
    m_acode(2) = &HC0330189
    m_acode(3) = &H90000CC2
   'AddRef Release共用
    m_acode(4) = &HC240C033
    m_acode(5) = &H90900004
    
    m_vtab(0) = VarPtr(m_acode(0))
    m_vtab(1) = VarPtr(m_acode(4))
    m_vtab(2) = m_vtab(1)
    
    p = VarPtr(m_acode(6))
    nfun = 3
    For narg = 0 To 9
        n = MakeCallFunAddrCode(p,narg)
        m_vtab(nfun) = p
        p = p + n
        nfun = nfun + 1
    Next
    
    p = VarPtr(m_cthis)
    CopyMemory VarPtr(m_ICallFunAddr),VarPtr(p),4
    Set MakeCallFunAddrObj = m_ICallFunAddr
End Function

以下是调用测试

Dim m_ICallFunAddr As ICallFunAddr

Private Sub Test_com()
Dim obj As Object
    Set obj = Dll_GetClassObject("D:AdministratorDocumentsVB6.0内联汇编_类成员函数调用aatest2.dll","{6D926E71-56E7-467D-B64F-E7571EF1B806}","{B1F1024A-7CF1-44C8-B34B-B7BE383F4825}")
    MsgBox TypeName(obj)
    obj.testadd 1,2,"abc"
End Sub

Public Sub Test_CallClassMember()
    Dim fun As Long
    Dim c As New Class1
    Dim p As Long
    Dim n As Long
    p = ObjPtr(c)
    fun = GetClassMemberAddr(p,7)
    n = 3
    m_ICallFunAddr.arg3 fun,p,1,VarPtr(n)
End Sub

'中断
Sub Test_int3()
    Dim code As Long
    code = &H9090C3CC
    m_ICallFunAddr.Arg0 VarPtr(code)
End Sub

Sub Test_CallFunAddr()
    Dim dll As Long
    Dim addr As Long
    Dim buf As String
    Dim n As Long
    Dim s As String
    
    buf = String(500,"0")
    dll = LoadLibraryW(StrPtr("user32.dll"))
    addr = GetProcAddress(dll,"wsprintfW")
    'cdecl方式
    n = m_ICallFunAddr.arg4(addr,StrPtr(buf),StrPtr("字符串:%s,数字%d"),StrPtr("中文12345+"),1234)
    addr = GetProcAddress(dll,"MessageBoxW")
    'stdcall方式
    m_ICallFunAddr.arg4 addr,Me.hWnd,StrPtr("MessageBoxW"),vbOKCancel
    s = Left(buf,n)
    s = "长度:" & n & vbCrLf & s
    MsgBox s
End Sub

Private Sub Form_Load()
    Set m_ICallFunAddr = MakeCallFunAddrObj
    Test_com
    'Test_CallClassMember
    'Test_int3
    'Test_CallFunAddr
End Sub

类型库，用vc6的mktyplib生成

[
    uuid(2399BACC-768E-4e37-8B98-80EC39BE4772)
]
library tlb_callFunAddr
{
	importlib("stdole2.tlb");

	[uuid(316462C8-FDBA-45f7-856B-325C1AD39737),odl]
	interface ICallFunAddr : IUnknown
	{
		long Arg0([in] long addr);
		long Arg1([in] long addr,[in] long arg1);
		long Arg2([in] long addr,[in] long arg1,[in] long arg2);
		long Arg3([in] long addr,[in] long arg2,[in] long arg3);
		long Arg4([in] long addr,[in] long arg3,[in] long arg4);
		long Arg5([in] long addr,[in] long arg4,[in] long arg5);
		long Arg6([in] long addr,[in] long arg5,[in] long arg6);
		long Arg7([in] long addr,[in] long arg6,[in] long arg7);
		long Arg8([in] long addr,[in] long arg7,[in] long arg8);
		long Arg9([in] long addr,[in] long arg8,[in] long arg9);
	};

	[uuid(00000001-0000-0000-C000-000000000046),odl]
	interface IClassFactory : IUnknown
	{
		long CreateInstance([in] long pUnkOuter,[in] long riid,[in] IUnknown** ppvObject);
		long LockServer([in] long fLock);
	};
};

clsid我是用eXeScope查看的，挺好用的一个软件，汇编是ollydbg里面打的，也用它调试。

vb6生成的pdb调试文件貌似每次生成新的，要手动删除以前的，害我调试错乱，花了好多时间。

（编辑：李大同）

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