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Copy pathdetourxs.cpp
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executable file
·203 lines (166 loc) · 5.5 KB
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#include "detourxs.h"
DetourXS::DetourXS()
{
m_detourLen = 0;
m_Created = FALSE;
}
DetourXS::DetourXS(LPVOID lpFuncOrig, LPVOID lpFuncDetour)
{
m_detourLen = 0;
Create(lpFuncOrig, lpFuncDetour);
}
DetourXS::~DetourXS()
{
Destroy();
}
BOOL DetourXS::Create(const LPVOID lpFuncOrig, const LPVOID lpFuncDetour)
{
DWORD dwProt;
// Already created, need to Destroy() first
if(m_Created == TRUE)
{
return FALSE;
}
// Init
m_lpFuncOrig = RecurseJumps(lpFuncOrig);
m_lpFuncDetour = lpFuncDetour;
m_lpbFuncOrig = reinterpret_cast<LPBYTE>(m_lpFuncOrig);
m_lpbFuncDetour = reinterpret_cast<LPBYTE>(m_lpFuncDetour);
m_trampoline.resize(50, 0x00); // data() must not be relocated to determine jmp type
// Determine which jump is necessary
m_OrigJmp = GetJmpType(m_lpbFuncOrig, m_lpbFuncDetour);
m_TrampJmp = GetJmpType(m_trampoline.data(), m_lpbFuncOrig);
// Determine detour length
if(m_detourLen == 0 && (m_detourLen = GetDetourLenAuto(m_lpFuncOrig, m_OrigJmp)) == 0)
{
return FALSE;
}
// Copy orig bytes to trampoline
std::copy(m_lpbFuncOrig, m_lpbFuncOrig + m_detourLen, m_trampoline.begin());
// Write a jump to the orig from the tramp
WriteJump(m_trampoline.data() + m_detourLen, m_lpbFuncOrig + m_detourLen, m_TrampJmp);
// Trim the tramp
m_trampoline.resize(m_detourLen + m_TrampJmp);
// Enable full access for when tramp is executed
if(VirtualProtect(m_trampoline.data(), m_trampoline.size(), PAGE_EXECUTE_READWRITE, &dwProt) == FALSE) { return FALSE; }
// Write jump from orig to detour
if(VirtualProtect(m_lpFuncOrig, m_detourLen, PAGE_EXECUTE_READWRITE, &dwProt) == FALSE) { return FALSE; }
memset(m_lpFuncOrig, 0x90, m_detourLen);
WriteJump(m_lpbFuncOrig, m_lpbFuncDetour);
VirtualProtect(m_lpFuncOrig, m_detourLen, dwProt, &dwProt);
// Flush cache to make sure CPU doesn't execute old instructions
FlushInstructionCache(GetCurrentProcess(), m_lpFuncOrig, m_detourLen);
m_Created = TRUE;
return TRUE;
}
BOOL DetourXS::Destroy()
{
DWORD dwProt;
VirtualProtect(m_lpFuncOrig, m_detourLen, PAGE_EXECUTE_READWRITE, &dwProt);
memcpy(m_lpFuncOrig, m_trampoline.data(), m_detourLen);
VirtualProtect(m_lpFuncOrig, m_detourLen, dwProt, &dwProt);
m_trampoline.clear();
m_detourLen = 0;
m_Created = FALSE;
return TRUE;
}
LPVOID DetourXS::RecurseJumps(LPVOID lpAddr)
{
LPBYTE lpbAddr = reinterpret_cast<LPBYTE>(lpAddr);
// Absolute
if(*lpbAddr == 0xFF && *(lpbAddr + 1) == 0x25)
{
LPVOID lpDest = nullptr;
#ifdef _M_IX86
lpDest = **reinterpret_cast<LPVOID**>( lpbAddr + 2 );
#else
if(*reinterpret_cast<DWORD*>(lpbAddr + 2) != 0)
{
lpDest = *reinterpret_cast<LPVOID**>( lpbAddr + *reinterpret_cast<PDWORD>(lpbAddr + 2) + 6 );
}
else
{
lpDest = *reinterpret_cast<LPVOID**>( lpbAddr + 6 );
}
#endif
return RecurseJumps(lpDest);
}
// Relative Near
else if(*lpbAddr == 0xE9)
{
LPVOID lpDest = nullptr;
#ifdef _M_IX86
lpDest = reinterpret_cast<LPVOID>( *reinterpret_cast<PDWORD>(lpbAddr + 1) + reinterpret_cast<DWORD>(lpbAddr) + relativeJmpSize );
#else
lpDest = reinterpret_cast<LPVOID>( *reinterpret_cast<PDWORD>(lpbAddr + 1) + reinterpret_cast<DWORD>(lpbAddr) + relativeJmpSize
+ (reinterpret_cast<DWORD_PTR>(GetModuleHandle(NULL)) & 0xFFFFFFFF00000000) );
#endif
return RecurseJumps(lpDest);
}
// Relative Short
else if(*lpbAddr == 0xEB)
{
BYTE offset = *(lpbAddr + 1);
// Jmp forwards
if(offset > 0x00 && offset <= 0x7F)
{
LPVOID lpDest = reinterpret_cast<LPVOID>( lpbAddr + 2 + offset );
return RecurseJumps(lpDest);
}
// Jmp backwards
else if(offset > 0x80 && offset <= 0xFF) // tbh none should be > FD
{
offset = -abs(offset);
LPVOID lpDest = reinterpret_cast<LPVOID>( lpbAddr + 2 - offset );
return RecurseJumps(lpDest);
}
}
return lpAddr;
}
size_t DetourXS::GetDetourLenAuto(const LPVOID lpStart, JmpType jmpType)
{
size_t totalLen = 0;
LPBYTE lpbDataPos = reinterpret_cast<LPBYTE>(lpStart);
while(totalLen < jmpType)
{
size_t len = LDE(reinterpret_cast<LPVOID>(lpbDataPos), 0);
lpbDataPos += len;
totalLen += len;
}
return totalLen;
}
void DetourXS::WriteJump(const LPBYTE lpbFrom, const LPBYTE lpbTo)
{
JmpType jmpType = GetJmpType(lpbFrom, lpbTo);
WriteJump(lpbFrom, lpbTo, jmpType);
}
void DetourXS::WriteJump(const LPBYTE lpbFrom, const LPBYTE lpbTo, JmpType jmpType)
{
if(jmpType == Absolute)
{
lpbFrom[0] = 0xFF;
lpbFrom[1] = 0x25;
#ifdef _M_IX86
// FF 25 [ptr_to_jmp(4bytes)][jmp(4bytes)]
*reinterpret_cast<PDWORD>(lpbFrom + 2) = reinterpret_cast<DWORD>(lpbFrom) + 6;
*reinterpret_cast<PDWORD>(lpbFrom + 6) = reinterpret_cast<DWORD>(lpbTo);
#else
// FF 25 [ptr_to_jmp(4bytes)][jmp(8bytes)]
*reinterpret_cast<PDWORD>(lpbFrom + 2) = 0;
*reinterpret_cast<PDWORD_PTR>(lpbFrom + 6) = reinterpret_cast<DWORD_PTR>(lpbTo);
#endif
}
else if(jmpType == Relative)
{
// E9 [to - from - jmp_size]
lpbFrom[0] = 0xE9;
DWORD offset = reinterpret_cast<DWORD>(lpbTo) - reinterpret_cast<DWORD>(lpbFrom) - relativeJmpSize;
*reinterpret_cast<PDWORD>(lpbFrom + 1) = static_cast<DWORD>(offset);
}
}
DetourXS::JmpType DetourXS::GetJmpType(const LPBYTE lpbFrom, const LPBYTE lpbTo)
{
const DWORD_PTR upper = reinterpret_cast<DWORD_PTR>((std::max)(lpbFrom, lpbTo));
const DWORD_PTR lower = reinterpret_cast<DWORD_PTR>((std::min)(lpbFrom, lpbTo));
return (upper - lower > 0x7FFFFFFF) ? Absolute : Relative;
}