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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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51
boot/xtldr/arch/i686/memory.cc
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@@ -25,13 +25,12 @@ EFI_STATUS
Memory::BuildPageMap(IN PXTBL_PAGE_MAPPING PageMap,
IN ULONG_PTR SelfMapAddress)
{
PLIST_ENTRY ListEntry, ModulesList, ModulesListEntry;
EFI_PHYSICAL_ADDRESS Address, DirectoryAddress;
PLIST_ENTRY ModulesList, ModulesListEntry;
PXTBL_MODULE_INFO ModuleInfo;
PXTBL_MEMORY_MAPPING Mapping;
PVOID LoaderBase;
ULONGLONG LoaderSize;
EFI_STATUS Status;
PVOID LoaderBase;
ULONG Index;
/* Check the page map level to determine which paging structure to create */
@@ -45,6 +44,14 @@ Memory::BuildPageMap(IN PXTBL_PAGE_MAPPING PageMap,
return Status;
}
/* Add new memory mapping for the page map itself */
Status = MapVirtualMemory(PageMap, (ULONGLONG)NULLPTR, Address, 1, LoaderMemoryData);
if(Status != STATUS_EFI_SUCCESS)
{
/* Memory mapping failure */
return Status;
}
/* Assign the allocated page to the page map and zero it out */
PageMap->PtePointer = (PVOID)(UINT_PTR)Address;
RTL::Memory::ZeroMemory(PageMap->PtePointer, EFI_PAGE_SIZE);
@@ -57,6 +64,14 @@ Memory::BuildPageMap(IN PXTBL_PAGE_MAPPING PageMap,
return Status;
}
/* Add new memory mapping for the Page Directories (PDs) */
Status = MapVirtualMemory(PageMap, (ULONGLONG)NULLPTR, DirectoryAddress, 4, LoaderMemoryData);
if(Status != STATUS_EFI_SUCCESS)
{
/* Memory mapping failure */
return Status;
}
/* Zero-fill the allocated memory for the Page Directories */
RTL::Memory::ZeroMemory((PVOID)DirectoryAddress, EFI_PAGE_SIZE * 4);
@@ -79,6 +94,14 @@ Memory::BuildPageMap(IN PXTBL_PAGE_MAPPING PageMap,
return Status;
}
/* Add new memory mapping for the page map itself */
Status = MapVirtualMemory(PageMap, (ULONGLONG)NULLPTR, Address, 1, LoaderMemoryData);
if(Status != STATUS_EFI_SUCCESS)
{
/* Memory mapping failure */
return Status;
}
/* Assign the allocated page to the page map and zero it out */
PageMap->PtePointer = (PVOID)(UINT_PTR)Address;
RTL::Memory::ZeroMemory(PageMap->PtePointer, EFI_PAGE_SIZE);
@@ -144,6 +167,28 @@ Memory::BuildPageMap(IN PXTBL_PAGE_MAPPING PageMap,
return STATUS_EFI_PROTOCOL_ERROR;
}
/* Return success */
return STATUS_EFI_SUCCESS;
}
/**
* Iterates through the memory map and physically maps all virtual addresses to page tables.
*
* @param PageMap
* Supplies a pointer to the page mapping structure.
*
* @return This routine returns a status code.
*
* @since XT 1.0
*/
XTCDECL
EFI_STATUS
Memory::CommitPageMap(IN PXTBL_PAGE_MAPPING PageMap)
{
PXTBL_MEMORY_MAPPING Mapping;
PLIST_ENTRY ListEntry;
EFI_STATUS Status;
/* Iterate through and map all the mappings*/
Debug::Print(L"Mapping and dumping EFI memory:\n");
ListEntry = PageMap->MemoryMap.Flink;