LPVOID VirtualAllocWrapper::Alloc(LPVOID lpAddress, size_t dwSize, DWORD allocationType, DWORD protectFlags, bool isCustomHeapAllocation)
{
Assert(this == nullptr);
LPVOID address = nullptr;
#if defined(ENABLE_JIT_CLAMP)
bool makeExecutable;
if ((isCustomHeapAllocation) ||
(protectFlags & (PAGE_EXECUTE | PAGE_EXECUTE_READ | PAGE_EXECUTE_READWRITE)))
{
makeExecutable = true;
}
else
{
makeExecutable = false;
}
AutoEnableDynamicCodeGen enableCodeGen(makeExecutable);
#endif
#if defined(_CONTROL_FLOW_GUARD)
DWORD oldProtectFlags;
if (AutoSystemInfo::Data.IsCFGEnabled() && isCustomHeapAllocation)
{
//We do the allocation in two steps - CFG Bitmap in kernel will be created only on allocation with EXECUTE flag.
//We again call VirtualProtect to set to the requested protectFlags.
DWORD allocProtectFlags = 0;
if (AutoSystemInfo::Data.IsCFGEnabled())
{
allocProtectFlags = PAGE_EXECUTE_RW_TARGETS_INVALID;
}
else
{
allocProtectFlags = PAGE_EXECUTE_READWRITE;
}
address = VirtualAlloc(lpAddress, dwSize, allocationType, allocProtectFlags);
VirtualProtect(address, dwSize, protectFlags, &oldProtectFlags);
}
else
#endif
{
address = VirtualAlloc(lpAddress, dwSize, allocationType, protectFlags);
}
return address;
}
LPVOID VirtualAllocWrapper::AllocPages(LPVOID lpAddress, size_t pageCount, DWORD allocationType, DWORD protectFlags, bool isCustomHeapAllocation)
{
if (pageCount > AutoSystemInfo::MaxPageCount)
{
return nullptr;
}
size_t dwSize = pageCount * AutoSystemInfo::PageSize;
LPVOID address = nullptr;
#if defined(ENABLE_JIT_CLAMP)
bool makeExecutable;
if ((isCustomHeapAllocation) ||
(protectFlags & (PAGE_EXECUTE | PAGE_EXECUTE_READ | PAGE_EXECUTE_READWRITE)))
{
makeExecutable = true;
}
else
{
makeExecutable = false;
}
AutoEnableDynamicCodeGen enableCodeGen(makeExecutable);
#endif
#if defined(_CONTROL_FLOW_GUARD)
DWORD oldProtectFlags = 0;
if (AutoSystemInfo::Data.IsCFGEnabled() && isCustomHeapAllocation)
{
//We do the allocation in two steps - CFG Bitmap in kernel will be created only on allocation with EXECUTE flag.
//We again call VirtualProtect to set to the requested protectFlags.
DWORD allocProtectFlags = 0;
if (AutoSystemInfo::Data.IsCFGEnabled())
{
allocProtectFlags = PAGE_EXECUTE_RW_TARGETS_INVALID;
}
else
{
allocProtectFlags = PAGE_EXECUTE_READWRITE;
}
address = VirtualAlloc(lpAddress, dwSize, allocationType, allocProtectFlags);
if (address == nullptr)
{
MemoryOperationLastError::RecordLastError();
return nullptr;
}
else if ((allocationType & MEM_COMMIT) == MEM_COMMIT) // The access protection value can be set only on committed pages.
{
BOOL result = VirtualProtect(address, dwSize, protectFlags, &oldProtectFlags);
if (result == FALSE)
{
CustomHeap_BadPageState_fatal_error((ULONG_PTR)this);
}
}
}
else
#endif
{
address = VirtualAlloc(lpAddress, dwSize, allocationType, protectFlags);
if (address == nullptr)
{
MemoryOperationLastError::RecordLastError();
return nullptr;
}
}
return address;
}
