Delphi下调用API Hook　
 

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uses
SysUtils,
Windows,
Classes,
HookAPI in 'HookAPI.pas',
Main in 'Main.pas';

var
Hook:HHOOK;

function GetMsgProc(nCode:Integer;wParam:wParam;lParam:lParam):LRESULT;stdcall;
begin
Result := 0;
end;

procedure SetHook;
begin
Hook := SetWindowsHookEx(WH_GETMESSAGE,GetMsgProc,hInstance,0);
end;

procedure RemoveHook;
begin
UnHookWindowsHookEx(Hook);
end;

{$R *.RES}

exports
SetHook, RemoveHook;

begin
API_Hookup;
end.






unit Main;

interface
uses
SysUtils,
Windows,
ShellAPI,
Dialogs,
Classes;

procedure API_Hookup; stdcall;
procedure API_HookDown; stdcall;

type
TCreateProcess = function(lpApplicationName: PChar; lpCommandLine: PChar;
lpProcessAttributes, lpThreadAttributes: PSecurityAttributes;
bInheritHandles: BOOL; dwCreationFlags: DWORD; lpEnvironment: Pointer;
lpCurrentDirectory: PChar; const lpStartupInfo: TStartupInfo;
var lpProcessInformation: TProcessInformation): BOOL; stdcall;
TCreateProcessA = function(lpApplicationName: PAnsiChar; lpCommandLine: PAnsiChar;
lpProcessAttributes, lpThreadAttributes: PSecurityAttributes;
bInheritHandles: BOOL; dwCreationFlags: DWORD; lpEnvironment: Pointer;
lpCurrentDirectory: PAnsiChar; const lpStartupInfo: TStartupInfo;
var lpProcessInformation: TProcessInformation): BOOL; stdcall;
TCreateProcessW = function(lpApplicationName: PWideChar; lpCommandLine: PWideChar;
lpProcessAttributes, lpThreadAttributes: PSecurityAttributes;
bInheritHandles: BOOL; dwCreationFlags: DWORD; lpEnvironment: Pointer;
lpCurrentDirectory: PWideChar; const lpStartupInfo: TStartupInfo;
var lpProcessInformation: TProcessInformation): BOOL; stdcall;

var
OldCreateProcess: TCreateProcess;
OldCreateProcessA: TCreateProcessA;
OldCreateProcessW: TCreateProcessW;

implementation

uses HookAPI;

function MyCreateProcess(lpApplicationName: PChar; lpCommandLine: PChar;
lpProcessAttributes, lpThreadAttributes: PSecurityAttributes;
bInheritHandles: BOOL; dwCreationFlags: DWORD; lpEnvironment: Pointer;
lpCurrentDirectory: PChar; const lpStartupInfo: TStartupInfo;
var lpProcessInformation: TProcessInformation): BOOL; stdcall;
begin
ShowMessage('MyCreateProcess');
end;

function MyCreateProcessA(lpApplicationName: PAnsiChar; lpCommandLine: PAnsiChar;
lpProcessAttributes, lpThreadAttributes: PSecurityAttributes;
bInheritHandles: BOOL; dwCreationFlags: DWORD; lpEnvironment: Pointer;
lpCurrentDirectory: PAnsiChar; const lpStartupInfo: TStartupInfo;
var lpProcessInformation: TProcessInformation): BOOL; stdcall;
begin
ShowMessage('MyCreateProcessA');
end;

function MyCreateProcessW(lpApplicationName: PWideChar; lpCommandLine: PWideChar;
lpProcessAttributes, lpThreadAttributes: PSecurityAttributes;
bInheritHandles: BOOL; dwCreationFlags: DWORD; lpEnvironment: Pointer;
lpCurrentDirectory: PWideChar; const lpStartupInfo: TStartupInfo;
var lpProcessInformation: TProcessInformation): BOOL; stdcall;
begin
ShowMessage('MyCreateProcessW');
end;

procedure API_Hookup; stdcall;
begin
if @OldCreateProcess = nil then
@OldCreateProcess := LocateFunctionAddress(@CreateProcess);
if @OldCreateProcessA = nil then
@OldCreateProcessA := LocateFunctionAddress(@CreateProcessA);
if @OldCreateProcessW = nil then
@OldCreateProcessW := LocateFunctionAddress(@CreateProcessW);

RepointFunction(@OldCreateProcess, @MyCreateProcess);
RepointFunction(@OldCreateProcessA, @MyCreateProcessA);
RepointFunction(@OldCreateProcessW, @MyCreateProcessW);

end;

procedure API_HookDown; stdcall;
begin
if @OldCreateProcess <> nil then
RepointFunction(@MyCreateProcess, @OldCreateProcess);
if @OldCreateProcess <> nil then
RepointFunction(@MyCreateProcessA, @OldCreateProcessA);
if @OldCreateProcess <> nil then
RepointFunction(@MyCreateProcessW, @OldCreateProcessW);
end;

initialization

finalization
API_HookDown;

end.







unit HookAPI;

interface

uses
Windows, Classes;
function LocateFunctionAddress(Code: Pointer): Pointer;
function RepointFunction(OldFunc, NewFunc: Pointer): Integer;

type //ｶｨﾒ袵ｻｸ ・ﾚｽ盪ｹ
PImage_Import_Entry = ^Image_Import_Entry;
Image_Import_Entry = record
Characteristics: DWORD;
TimeDateStamp: DWORD;
MajorVersion: Word;
MinorVersion: Word;
Name: DWORD;
LookupTable: DWORD;
end;

type
TImportCode = packed record
JumpInstruction: Word;
AddressOfPointerToFunction: ^Pointer;
end;
PImportCode = ^TImportCode;
implementation

function LocateFunctionAddress(Code: Pointer): Pointer;
var
func: PImportCode;
begin
Result := Code;
if Code = nil then exit;
try
func := code;
if (func.JumpInstruction = $25FF) then
begin
Result := func.AddressOfPointerToFunction^;
end;
except
Result := nil;
end;
end;

function RepointFunction(OldFunc, NewFunc: Pointer): Integer;
var
IsDone: TList;
function RepointAddrInModule(hModule: THandle; OldFunc, NewFunc: Pointer): Integer;
var
Dos: PImageDosHeader;
NT: PImageNTHeaders;
ImportDesc: PImage_Import_Entry;
RVA: DWORD;
Func: ^Pointer;
DLL: string;
f: Pointer;
written: DWORD;
begin
Result := 0;
Dos := Pointer(hModule);
if IsDone.IndexOf(Dos) >= 0 then exit;
IsDone.Add(Dos);

OldFunc := LocateFunctionAddress(OldFunc);

if IsBadReadPtr(Dos, SizeOf(TImageDosHeader)) then exit;
if Dos.e_magic <> IMAGE_DOS_SIGNATURE then exit;
NT := Pointer(Integer(Dos) + dos._lfanew);

RVA := NT^.OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT]
.VirtualAddress;

if RVA = 0 then exit;
ImportDesc := pointer(integer(Dos) + RVA);
while (ImportDesc^.Name <> 0) do
begin
DLL := PChar(Integer(Dos) + ImportDesc^.Name);
RepointAddrInModule(GetModuleHandle(PChar(DLL)), OldFunc, NewFunc);
Func := Pointer(Integer(DOS) + ImportDesc.LookupTable);
while Func^ <> nil do
begin
f := LocateFunctionAddress(Func^);
if f = OldFunc then
begin
WriteProcessMemory(GetCurrentProcess, Func, @NewFunc, 4, written);
if Written > 0 then Inc(Result);
end;
Inc(Func);
end;
Inc(ImportDesc);
end;
end;

begin
IsDone := TList.Create;
try
Result := RepointAddrInModule(GetModuleHandle(nil), OldFunc, NewFunc);
finally
IsDone.Free;
end;
end;

end.