Anmeldungsdatum: Feb 2011
Beiträge: 26
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TEXT Code: #ifndef __VMTHOOK_H__ #define __VMTHOOK_H__ #include <Windows.h> class CVMTHook { public: CVMTHook(void* instance); ~CVMTHook(); void* hookFunction(size_t iIndex, void* pfnHook); void* getOriginalFunction(size_t iIndex); void setHookEnabled(bool bEnabled=true); protected: size_t m_iNumIndices; void** m_pOriginalVTable; void** m_pNewVTable; void*** m_pInstance; }; #endif //__VMTHOOK_H__
TEXT Code: #include "VMTHook.h" CVMTHook::CVMTHook(void* instance) { HANDLE hProcessHeap; if(instance) { m_pInstance = (void***) instance; m_pOriginalVTable = *m_pInstance; //Count number of Pointers in the table m_iNumIndices = 0; //TODO: check if pointer into .text section while(m_pOriginalVTable[m_iNumIndices]) { m_iNumIndices++; } //Allocate memory on the heap for our own copy of the table hProcessHeap = GetProcessHeap(); if(hProcessHeap) { m_pNewVTable = (void**) HeapAlloc(hProcessHeap, 0, sizeof(void*) * m_iNumIndices); if(m_pNewVTable) { memcpy(m_pNewVTable, m_pOriginalVTable, sizeof(void*) * m_iNumIndices); setHookEnabled(); } } } } CVMTHook::~CVMTHook() { HANDLE hProcessHeap; //Reset the VTable pointer if(*m_pInstance == m_pNewVTable) { *m_pInstance = m_pOriginalVTable; } //Free our copy of the VTable hProcessHeap = GetProcessHeap(); if(hProcessHeap) { HeapFree(hProcessHeap, 0, m_pNewVTable); } } void* CVMTHook::getOriginalFunction(size_t iIndex) { return m_pOriginalVTable[iIndex]; } void* CVMTHook::hookFunction(size_t iIndex, void* pfnHook) { //Valid index? if(iIndex >= m_iNumIndices) return NULL; //Write new pointer m_pNewVTable[iIndex]=pfnHook; //And return pointer to original function return m_pOriginalVTable[iIndex]; } void CVMTHook::setHookEnabled(bool bEnabled) { if(bEnabled) { //Point to our copy of the VTable *m_pInstance=m_pNewVTable; } else { //Point to the original VTable *m_pInstance=m_pOriginalVTable; } }
Credits: Inurface, myself and me kk
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