CApiHook By gwsbhqt

 1 #pragma once
 2 
 3 #ifndef CAPIHOOK_H
 4 #define CAPIHOOK_H
 5 
 6 #include <cstdio>
 7 #include <windows.h>
 8 
 9 using namespace std;
10 
11 class CApiHook
12 {
13 public:
14     bool status;            // the status of Hook
15     HMODULE hModule;        // the dll moudle handle of original function
16     LPVOID lpOldFunAddr;        // the address of original function
17     LPVOID lpNewFunAddr;        // the address of Hook function
18     BYTE bOldByte[5];        // the raw data of the original address
19     BYTE bNewByte[5];        // the new data of the original address / the key jump statement of structure
20 
21     CApiHook();
22     bool Install(PSTR szModuleName, PSTR szFunName, FARPROC pFun);
23 
24 };
25 
26 #endif    //    define CAPIHOOK_H

 1 #include "CApiHook.h"
 2 
 3 CApiHook::CApiHook()
 4 {
 5     memset(this, 0, sizeof(CApiHook));
 6 }
 7 
 8 bool CApiHook::Install(PSTR szModuleName, PSTR szFunName, FARPROC pFun)
 9 {
10     if (status == true)
11         return false;
12 
13     hModule = GetModuleHandleA(szModuleName);
14     if (hModule == NULL)
15     {
16         hModule = LoadLibraryA(szModuleName);
17         if (hModule == NULL)
18             return false;
19     }
20 
21     lpNewFunAddr = (LPVOID)pFun;
22     lpOldFunAddr = (LPVOID)GetProcAddress(hModule, szFunName);
23     if (lpOldFunAddr == NULL)
24     {
25         CloseHandle(hModule);
26         return false;
27     }
28 
29     RtlMoveMemory(bOldByte, lpOldFunAddr, 5);
30 
31     bNewByte[0] = 0xE9;
32     *((PDWORD)(&(bNewByte[1]))) = (DWORD)lpNewFunAddr - (DWORD)lpOldFunAddr - 5;
33 
34 
35     MEMORY_BASIC_INFORMATION mbi;
36     if (VirtualQueryEx(GetCurrentProcess(), lpOldFunAddr, &mbi, sizeof(mbi)) == 0)
37     {
38         CloseHandle(hModule);
39         return false;
40     }
41 
42     DWORD dwOldProtect;
43     if (VirtualProtectEx(GetCurrentProcess(), mbi.BaseAddress, 5, PAGE_EXECUTE_READWRITE, &dwOldProtect) == 0)
44     {
45         CloseHandle(hModule);
46         return false;
47     }
48     
49     DWORD dwWriteByte;
50     if (WriteProcessMemory(GetCurrentProcess(), (LPVOID)lpOldFunAddr, bNewByte, 5, &dwWriteByte) == 0)
51     {
52         CloseHandle(hModule);
53         return false;
54     }
55 
56     if (VirtualProtectEx(GetCurrentProcess(), mbi.BaseAddress, 5, dwOldProtect, &dwOldProtect) == 0)
57     {
58         CloseHandle(hModule);
59         return false;
60     }
61     
62     return true;
63 }

 1 #include <cstdio>
 2 #include <windows.h>
 3 
 4 #include "CApiHook.h"
 5 
 6 using namespace std;
 7 
 8 CApiHook apihook;
 9 
10 typedef int (WINAPI* PFNMessageBoxA)(HWND hWnd, LPCSTR lpText, LPCSTR lpCaption, UINT uType);
11 
12 int WINAPI HookMessageBoxA(HWND hWnd, LPCSTR lpText, LPCSTR lpCaption, UINT uType)
13 {
14     printf("here~!");
15 
16     return 0;
17 }
18 
19 int main()
20 {
21     apihook.Install("User32.dll", "MessageBoxA", (FARPROC)HookMessageBoxA);
22 
23     MessageBoxA(NULL, "Hello Me~", "", MB_OK | MB_ICONINFORMATION);
24 
25     printf("HelloWorld!\n\n");
26 
27     system("pause");
28     return 0;
29 }