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Fix critical memory corruption bug caused by overwriting active page tables marked as free memory
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This commit is contained in:
Aiken Harris
2026-03-12 19:02:58 +01:00
parent 5fe0740c2e
commit 21b3b269a7
8 changed files with 304 additions and 156 deletions
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75
boot/xtldr/modules/xtos_o/i686/memory.cc
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@@ -9,6 +9,47 @@
#include <xtos.hh>
XTCDECL
EFI_STATUS
Xtos::BuildPageMap(IN PXTBL_PAGE_MAPPING PageMap)
{
ULONG_PTR SelfMapAddress;
EFI_STATUS Status;
/* Initialize self map address */
if(PageMap->PageMapLevel == 3)
{
/* For PML3 (PAE) use PTE base address */
SelfMapAddress = MM_PTE_BASE;
}
else
{
/* For PML2 (PAE disabled) use legacy PDE base address */
SelfMapAddress = MM_PDE_LEGACY_BASE;
}
/* Build page map */
Status = XtLdrProtocol->Memory.BuildPageMap(PageMap, SelfMapAddress);
if(Status != STATUS_EFI_SUCCESS)
{
/* Failed to build page map */
XtLdrProtocol->Debug.Print(L"Failed to build page map (Status code: %zX)\n", Status);
return Status;
}
/* Map memory for hardware layer */
Status = MapHardwareMemoryPool(PageMap);
if(Status != STATUS_EFI_SUCCESS)
{
/* Failed to map memory for hardware layer */
XtLdrProtocol->Debug.Print(L"Failed to map memory for hardware layer (Status code: %zX)\n", Status);
return Status;
}
/* Return success */
return STATUS_EFI_SUCCESS;
}
/**
* Determines the appropriate EFI memory mapping strategy for the i686 architecture.
*
@@ -74,37 +115,6 @@ EFI_STATUS
Xtos::EnablePaging(IN PXTBL_PAGE_MAPPING PageMap)
{
EFI_STATUS Status;
ULONG_PTR SelfMapAddress;
/* Initialize self map address */
if(PageMap->PageMapLevel == 3)
{
/* For PML3 (PAE) use PTE base address */
SelfMapAddress = MM_PTE_BASE;
}
else
{
/* For PML2 (PAE disabled) use legacy PDE base address */
SelfMapAddress = MM_PDE_LEGACY_BASE;
}
/* Build page map */
Status = XtLdrProtocol->Memory.BuildPageMap(PageMap, SelfMapAddress);
if(Status != STATUS_EFI_SUCCESS)
{
/* Failed to build page map */
XtLdrProtocol->Debug.Print(L"Failed to build page map (Status code: %zX)\n", Status);
return Status;
}
/* Map memory for hardware layer */
Status = MapHardwareMemoryPool(PageMap);
if(Status != STATUS_EFI_SUCCESS)
{
/* Failed to map memory for hardware layer */
XtLdrProtocol->Debug.Print(L"Failed to map memory for hardware layer (Status code: %zX)\n", Status);
return Status;
}
/* Exit EFI Boot Services */
XtLdrProtocol->Debug.Print(L"Exiting EFI boot services\n");
@@ -173,6 +183,9 @@ Xtos::MapHardwareMemoryPool(IN PXTBL_PAGE_MAPPING PageMap)
/* Zero fill allocated memory */
XtLdrProtocol->Memory.ZeroMemory((PVOID)Address, EFI_PAGE_SIZE);
/* Map hardware memory */
XtLdrProtocol->Memory.MapVirtualMemory(PageMap, (ULONGLONG)NULLPTR, Address, 1, LoaderMemoryData);
/* Check if PAE is enabled (3-level paging) */
if(PageMap->PageMapLevel == 3)
{