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MemoryProtection.c
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MemoryProtection.c
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/** @file
UEFI Memory Protection support.
If the UEFI image is page aligned, the image code section is set to read only
and the image data section is set to non-executable.
1) This policy is applied for all UEFI image including boot service driver,
runtime driver or application.
2) This policy is applied only if the UEFI image meets the page alignment
requirement.
3) This policy is applied only if the Source UEFI image matches the
Image Protection Policy definition. // MU_CHANGE
4) This policy is not applied to the non-PE image region.
The DxeCore calls CpuArchProtocol->SetMemoryAttributes() to protect
the image. If the CpuArch protocol is not installed yet, the DxeCore
enqueues the protection request. Once the CpuArch is installed, the
DxeCore dequeues the protection request and applies policy.
Once the image is unloaded, the protection is removed automatically.
Copyright (c) 2017 - 2018, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <PiDxe.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/DxeServicesTableLib.h>
#include <Library/DebugLib.h>
#include <Library/UefiLib.h>
#include <Guid/EventGroup.h>
#include <Guid/MemoryAttributesTable.h>
#include <Protocol/FirmwareVolume2.h>
#include <Protocol/SimpleFileSystem.h>
#include <Protocol/MemoryProtectionDebug.h> // MU_CHANGE
#include <Protocol/MemoryAttribute.h> // MU_CHANGE
#include "DxeMain.h"
#include "Mem/HeapGuard.h"
#include "MemoryProtectionSupport.h"
//
// Image type definitions
//
#define IMAGE_UNKNOWN 0x00000001
#define IMAGE_FROM_FV 0x00000002
//
// Protection policy bit definition
//
// MU_CHANGE START: Moved to MemoryProtectionSupport.h
// #define DO_NOT_PROTECT 0x00000000
// #define PROTECT_IF_ALIGNED_ELSE_ALLOW 0x00000001
// MU_CHANG END
#define MEMORY_TYPE_OS_RESERVED_MIN 0x80000000
#define MEMORY_TYPE_OEM_RESERVED_MIN 0x70000000
#define PREVIOUS_MEMORY_DESCRIPTOR(MemoryDescriptor, Size) \
((EFI_MEMORY_DESCRIPTOR *)((UINT8 *)(MemoryDescriptor) - (Size)))
// UINT32 mImageProtectionPolicy; // MU_CHANGE
extern LIST_ENTRY mGcdMemorySpaceMap;
EFI_MEMORY_ATTRIBUTE_PROTOCOL *mMemoryAttribute = NULL; // MU_CHANGE
STATIC LIST_ENTRY mProtectedImageRecordList;
// MS_CHANGE - START
STATIC MEMORY_PROTECTION_DEBUG_PROTOCOL mMemoryProtectionDebug =
{
IsGuardPage,
GetImageList
};
// MS_CHANGE - END
/**
Sort code section in image record, based upon CodeSegmentBase from low to high.
@param ImageRecord image record to be sorted
**/
VOID
SortImageRecordCodeSection (
IN IMAGE_PROPERTIES_RECORD *ImageRecord
);
/**
Check if code section in image record is valid.
@param ImageRecord image record to be checked
@retval TRUE image record is valid
@retval FALSE image record is invalid
**/
BOOLEAN
IsImageRecordCodeSectionValid (
IN IMAGE_PROPERTIES_RECORD *ImageRecord
);
/**
Get the image type.
@param[in] File This is a pointer to the device path of the file that is
being dispatched.
@return UINT32 Image Type
**/
UINT32
GetImageType (
IN CONST EFI_DEVICE_PATH_PROTOCOL *File
)
{
EFI_STATUS Status;
EFI_HANDLE DeviceHandle;
EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
if (File == NULL) {
return IMAGE_UNKNOWN;
}
//
// First check to see if File is from a Firmware Volume
//
DeviceHandle = NULL;
TempDevicePath = (EFI_DEVICE_PATH_PROTOCOL *)File;
Status = gBS->LocateDevicePath (
&gEfiFirmwareVolume2ProtocolGuid,
&TempDevicePath,
&DeviceHandle
);
if (!EFI_ERROR (Status)) {
Status = gBS->OpenProtocol (
DeviceHandle,
&gEfiFirmwareVolume2ProtocolGuid,
NULL,
NULL,
NULL,
EFI_OPEN_PROTOCOL_TEST_PROTOCOL
);
if (!EFI_ERROR (Status)) {
return IMAGE_FROM_FV;
}
}
return IMAGE_UNKNOWN;
}
/**
Get UEFI image protection policy based upon image type.
@param[in] ImageType The UEFI image type
@return UEFI image protection policy
**/
UINT32
GetProtectionPolicyFromImageType (
IN UINT32 ImageType
)
{
// MU_CHANGE START Use ImageProtectionPolicy Bitfield
// if ((ImageType & mImageProtectionPolicy) == 0) {
// return DO_NOT_PROTECT;
// } else {
// return PROTECT_IF_ALIGNED_ELSE_ALLOW;
// }
if (((ImageType == IMAGE_UNKNOWN) && gDxeMps.ImageProtectionPolicy.Fields.ProtectImageFromUnknown) ||
((ImageType == IMAGE_FROM_FV) && gDxeMps.ImageProtectionPolicy.Fields.ProtectImageFromFv))
{
if (gDxeMps.ImageProtectionPolicy.Fields.RaiseErrorIfProtectionFails) {
return PROTECT_ELSE_RAISE_ERROR;
}
return PROTECT_IF_ALIGNED_ELSE_ALLOW;
} else {
return DO_NOT_PROTECT;
}
// MU_CHANGE END
}
/**
Get UEFI image protection policy based upon loaded image device path.
@param[in] LoadedImage The loaded image protocol
@param[in] LoadedImageDevicePath The loaded image device path protocol
@return UEFI image protection policy
**/
UINT32
GetUefiImageProtectionPolicy (
IN EFI_LOADED_IMAGE_PROTOCOL *LoadedImage,
IN EFI_DEVICE_PATH_PROTOCOL *LoadedImageDevicePath
)
{
BOOLEAN InSmm;
UINT32 ImageType;
UINT32 ProtectionPolicy;
DXE_MEMORY_PROTECTION_SETTINGS *Settings = NULL;
//
// Check SMM
//
InSmm = FALSE;
if (gSmmBase2 != NULL) {
gSmmBase2->InSmm (gSmmBase2, &InSmm);
}
if (InSmm) {
return FALSE;
}
//
// Check DevicePath
//
if (LoadedImage == gDxeCoreLoadedImage) {
// MU_CHANGE START
// If the image is DxeCore, DxeMemoryProtectionHobLib entry point has not
// yet executed and so gDxeMps is not yet valid. Get the memory protection
// HOB directly and check if DxeCore should be protected.
Settings = GetDxeMemoryProtectionSettings ();
if (Settings != NULL) {
if (Settings->ImageProtectionPolicy.Fields.ProtectImageFromFv == 1) {
if (Settings->ImageProtectionPolicy.Fields.RaiseErrorIfProtectionFails == 1) {
return PROTECT_ELSE_RAISE_ERROR;
}
return PROTECT_IF_ALIGNED_ELSE_ALLOW;
}
}
// MU_CHANGE END
ImageType = IMAGE_FROM_FV;
} else {
ImageType = GetImageType (LoadedImageDevicePath);
}
ProtectionPolicy = GetProtectionPolicyFromImageType (ImageType);
return ProtectionPolicy;
}
/**
Set UEFI image memory attributes.
@param[in] BaseAddress Specified start address
@param[in] Length Specified length
@param[in] Attributes Specified attributes
**/
VOID
SetUefiImageMemoryAttributes (
IN UINT64 BaseAddress,
IN UINT64 Length,
IN UINT64 Attributes
)
{
EFI_STATUS Status;
EFI_GCD_MEMORY_SPACE_DESCRIPTOR Descriptor;
UINT64 FinalAttributes;
Status = CoreGetMemorySpaceDescriptor (BaseAddress, &Descriptor);
ASSERT_EFI_ERROR (Status);
FinalAttributes = (Descriptor.Attributes & EFI_CACHE_ATTRIBUTE_MASK) | (Attributes & EFI_MEMORY_ATTRIBUTE_MASK);
// MU_CHANGE START: Update verbosity to reduce excessive debug output
// DEBUG ((DEBUG_INFO, "SetUefiImageMemoryAttributes - 0x%016lx - 0x%016lx (0x%016lx)\n", BaseAddress, Length, FinalAttributes));
DEBUG ((DEBUG_VERBOSE, "SetUefiImageMemoryAttributes - 0x%016lx - 0x%016lx (0x%016lx)\n", BaseAddress, Length, FinalAttributes));
// MU_CHANGE END
ASSERT (gCpu != NULL);
// MU_CHANGE START: Don't dereference if gCpu is NULL
if (gCpu != NULL) {
gCpu->SetMemoryAttributes (gCpu, BaseAddress, Length, FinalAttributes);
}
// MU_CHANGE END
}
/**
Set UEFI image protection attributes.
@param[in] ImageRecord A UEFI image record
**/
VOID
SetUefiImageProtectionAttributes (
IN IMAGE_PROPERTIES_RECORD *ImageRecord
)
{
IMAGE_PROPERTIES_RECORD_CODE_SECTION *ImageRecordCodeSection;
LIST_ENTRY *ImageRecordCodeSectionLink;
LIST_ENTRY *ImageRecordCodeSectionEndLink;
LIST_ENTRY *ImageRecordCodeSectionList;
UINT64 CurrentBase;
UINT64 ImageEnd;
ImageRecordCodeSectionList = &ImageRecord->CodeSegmentList;
CurrentBase = ImageRecord->ImageBase;
ImageEnd = ImageRecord->ImageBase + ImageRecord->ImageSize;
ImageRecordCodeSectionLink = ImageRecordCodeSectionList->ForwardLink;
ImageRecordCodeSectionEndLink = ImageRecordCodeSectionList;
while (ImageRecordCodeSectionLink != ImageRecordCodeSectionEndLink) {
ImageRecordCodeSection = CR (
ImageRecordCodeSectionLink,
IMAGE_PROPERTIES_RECORD_CODE_SECTION,
Link,
IMAGE_PROPERTIES_RECORD_CODE_SECTION_SIGNATURE
);
ImageRecordCodeSectionLink = ImageRecordCodeSectionLink->ForwardLink;
ASSERT (CurrentBase <= ImageRecordCodeSection->CodeSegmentBase);
if (CurrentBase < ImageRecordCodeSection->CodeSegmentBase) {
//
// DATA
//
SetUefiImageMemoryAttributes (
CurrentBase,
ImageRecordCodeSection->CodeSegmentBase - CurrentBase,
EFI_MEMORY_XP
);
}
//
// CODE
//
SetUefiImageMemoryAttributes (
ImageRecordCodeSection->CodeSegmentBase,
ImageRecordCodeSection->CodeSegmentSize,
EFI_MEMORY_RO
);
CurrentBase = ImageRecordCodeSection->CodeSegmentBase + ImageRecordCodeSection->CodeSegmentSize;
}
//
// Last DATA
//
ASSERT (CurrentBase <= ImageEnd);
if (CurrentBase < ImageEnd) {
//
// DATA
//
SetUefiImageMemoryAttributes (
CurrentBase,
ImageEnd - CurrentBase,
EFI_MEMORY_XP
);
}
return;
}
/**
Return if the PE image section is aligned.
@param[in] SectionAlignment PE/COFF section alignment
@param[in] MemoryType PE/COFF image memory type
@retval TRUE The PE image section is aligned.
@retval FALSE The PE image section is not aligned.
**/
BOOLEAN
IsMemoryProtectionSectionAligned (
IN UINT32 SectionAlignment,
IN EFI_MEMORY_TYPE MemoryType
)
{
UINT32 PageAlignment;
switch (MemoryType) {
case EfiRuntimeServicesCode:
case EfiACPIMemoryNVS:
PageAlignment = RUNTIME_PAGE_ALLOCATION_GRANULARITY;
break;
case EfiRuntimeServicesData:
case EfiACPIReclaimMemory:
ASSERT (FALSE);
PageAlignment = RUNTIME_PAGE_ALLOCATION_GRANULARITY;
break;
case EfiBootServicesCode:
case EfiLoaderCode:
case EfiReservedMemoryType:
PageAlignment = EFI_PAGE_SIZE;
break;
default:
ASSERT (FALSE);
PageAlignment = EFI_PAGE_SIZE;
break;
}
if ((SectionAlignment & (PageAlignment - 1)) != 0) {
return FALSE;
} else {
return TRUE;
}
}
/**
Free Image record.
@param[in] ImageRecord A UEFI image record
**/
VOID
FreeImageRecord (
IN IMAGE_PROPERTIES_RECORD *ImageRecord
)
{
LIST_ENTRY *CodeSegmentListHead;
IMAGE_PROPERTIES_RECORD_CODE_SECTION *ImageRecordCodeSection;
CodeSegmentListHead = &ImageRecord->CodeSegmentList;
while (!IsListEmpty (CodeSegmentListHead)) {
ImageRecordCodeSection = CR (
CodeSegmentListHead->ForwardLink,
IMAGE_PROPERTIES_RECORD_CODE_SECTION,
Link,
IMAGE_PROPERTIES_RECORD_CODE_SECTION_SIGNATURE
);
RemoveEntryList (&ImageRecordCodeSection->Link);
FreePool (ImageRecordCodeSection);
}
if (ImageRecord->Link.ForwardLink != NULL) {
RemoveEntryList (&ImageRecord->Link);
}
FreePool (ImageRecord);
}
/**
Protect UEFI PE/COFF image.
@param[in] LoadedImage The loaded image protocol
@param[in] LoadedImageDevicePath The loaded image device path protocol
**/
VOID
ProtectUefiImage (
IN EFI_LOADED_IMAGE_PROTOCOL *LoadedImage,
IN EFI_DEVICE_PATH_PROTOCOL *LoadedImageDevicePath
)
{
VOID *ImageAddress;
EFI_IMAGE_DOS_HEADER *DosHdr;
UINT32 PeCoffHeaderOffset;
UINT32 SectionAlignment;
EFI_IMAGE_SECTION_HEADER *Section;
EFI_IMAGE_OPTIONAL_HEADER_PTR_UNION Hdr;
UINT8 *Name;
UINTN Index;
IMAGE_PROPERTIES_RECORD *ImageRecord;
CHAR8 *PdbPointer;
IMAGE_PROPERTIES_RECORD_CODE_SECTION *ImageRecordCodeSection;
BOOLEAN IsAligned;
UINT32 ProtectionPolicy;
DEBUG ((DEBUG_INFO, "ProtectUefiImageCommon - 0x%x\n", LoadedImage));
DEBUG ((DEBUG_INFO, " - 0x%016lx - 0x%016lx\n", (EFI_PHYSICAL_ADDRESS)(UINTN)LoadedImage->ImageBase, LoadedImage->ImageSize));
if (gCpu == NULL) {
return;
}
ProtectionPolicy = GetUefiImageProtectionPolicy (LoadedImage, LoadedImageDevicePath);
switch (ProtectionPolicy) {
case DO_NOT_PROTECT:
return;
case PROTECT_IF_ALIGNED_ELSE_ALLOW:
break;
default:
ASSERT (FALSE);
return;
}
ImageRecord = AllocateZeroPool (sizeof (*ImageRecord));
if (ImageRecord == NULL) {
return;
}
ImageRecord->Signature = IMAGE_PROPERTIES_RECORD_SIGNATURE;
//
// Step 1: record whole region
//
ImageRecord->ImageBase = (EFI_PHYSICAL_ADDRESS)(UINTN)LoadedImage->ImageBase;
ImageRecord->ImageSize = LoadedImage->ImageSize;
ImageAddress = LoadedImage->ImageBase;
PdbPointer = PeCoffLoaderGetPdbPointer ((VOID *)(UINTN)ImageAddress);
if (PdbPointer != NULL) {
DEBUG ((DEBUG_VERBOSE, " Image - %a\n", PdbPointer));
}
//
// Check PE/COFF image
//
DosHdr = (EFI_IMAGE_DOS_HEADER *)(UINTN)ImageAddress;
PeCoffHeaderOffset = 0;
if (DosHdr->e_magic == EFI_IMAGE_DOS_SIGNATURE) {
PeCoffHeaderOffset = DosHdr->e_lfanew;
}
Hdr.Pe32 = (EFI_IMAGE_NT_HEADERS32 *)((UINT8 *)(UINTN)ImageAddress + PeCoffHeaderOffset);
if (Hdr.Pe32->Signature != EFI_IMAGE_NT_SIGNATURE) {
DEBUG ((DEBUG_VERBOSE, "Hdr.Pe32->Signature invalid - 0x%x\n", Hdr.Pe32->Signature));
// It might be image in SMM.
goto Finish;
}
//
// Get SectionAlignment
//
if (Hdr.Pe32->OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR32_MAGIC) {
SectionAlignment = Hdr.Pe32->OptionalHeader.SectionAlignment;
} else {
SectionAlignment = Hdr.Pe32Plus->OptionalHeader.SectionAlignment;
}
IsAligned = IsMemoryProtectionSectionAligned (SectionAlignment, LoadedImage->ImageCodeType);
if (!IsAligned) {
DEBUG ((
DEBUG_VERBOSE,
"!!!!!!!! ProtectUefiImageCommon - Section Alignment(0x%x) is incorrect !!!!!!!!\n",
SectionAlignment
));
PdbPointer = PeCoffLoaderGetPdbPointer ((VOID *)(UINTN)ImageAddress);
if (PdbPointer != NULL) {
DEBUG ((DEBUG_VERBOSE, "!!!!!!!! Image - %a !!!!!!!!\n", PdbPointer));
}
goto Finish;
}
Section = (EFI_IMAGE_SECTION_HEADER *)(
(UINT8 *)(UINTN)ImageAddress +
PeCoffHeaderOffset +
sizeof (UINT32) +
sizeof (EFI_IMAGE_FILE_HEADER) +
Hdr.Pe32->FileHeader.SizeOfOptionalHeader
);
ImageRecord->CodeSegmentCount = 0;
InitializeListHead (&ImageRecord->CodeSegmentList);
for (Index = 0; Index < Hdr.Pe32->FileHeader.NumberOfSections; Index++) {
Name = Section[Index].Name;
DEBUG ((
DEBUG_VERBOSE,
" Section - '%c%c%c%c%c%c%c%c'\n",
Name[0],
Name[1],
Name[2],
Name[3],
Name[4],
Name[5],
Name[6],
Name[7]
));
//
// Instead of assuming that a PE/COFF section of type EFI_IMAGE_SCN_CNT_CODE
// can always be mapped read-only, classify a section as a code section only
// if it has the executable attribute set and the writable attribute cleared.
//
// This adheres more closely to the PE/COFF spec, and avoids issues with
// Linux OS loaders that may consist of a single read/write/execute section.
//
if ((Section[Index].Characteristics & (EFI_IMAGE_SCN_MEM_WRITE | EFI_IMAGE_SCN_MEM_EXECUTE)) == EFI_IMAGE_SCN_MEM_EXECUTE) {
DEBUG ((DEBUG_VERBOSE, " VirtualSize - 0x%08x\n", Section[Index].Misc.VirtualSize));
DEBUG ((DEBUG_VERBOSE, " VirtualAddress - 0x%08x\n", Section[Index].VirtualAddress));
DEBUG ((DEBUG_VERBOSE, " SizeOfRawData - 0x%08x\n", Section[Index].SizeOfRawData));
DEBUG ((DEBUG_VERBOSE, " PointerToRawData - 0x%08x\n", Section[Index].PointerToRawData));
DEBUG ((DEBUG_VERBOSE, " PointerToRelocations - 0x%08x\n", Section[Index].PointerToRelocations));
DEBUG ((DEBUG_VERBOSE, " PointerToLinenumbers - 0x%08x\n", Section[Index].PointerToLinenumbers));
DEBUG ((DEBUG_VERBOSE, " NumberOfRelocations - 0x%08x\n", Section[Index].NumberOfRelocations));
DEBUG ((DEBUG_VERBOSE, " NumberOfLinenumbers - 0x%08x\n", Section[Index].NumberOfLinenumbers));
DEBUG ((DEBUG_VERBOSE, " Characteristics - 0x%08x\n", Section[Index].Characteristics));
//
// Step 2: record code section
//
ImageRecordCodeSection = AllocatePool (sizeof (*ImageRecordCodeSection));
if (ImageRecordCodeSection == NULL) {
return;
}
ImageRecordCodeSection->Signature = IMAGE_PROPERTIES_RECORD_CODE_SECTION_SIGNATURE;
ImageRecordCodeSection->CodeSegmentBase = (UINTN)ImageAddress + Section[Index].VirtualAddress;
ImageRecordCodeSection->CodeSegmentSize = ALIGN_VALUE (Section[Index].SizeOfRawData, SectionAlignment);
DEBUG ((DEBUG_VERBOSE, "ImageCode: 0x%016lx - 0x%016lx\n", ImageRecordCodeSection->CodeSegmentBase, ImageRecordCodeSection->CodeSegmentSize));
InsertTailList (&ImageRecord->CodeSegmentList, &ImageRecordCodeSection->Link);
ImageRecord->CodeSegmentCount++;
}
}
if (ImageRecord->CodeSegmentCount == 0) {
//
// If a UEFI executable consists of a single read+write+exec PE/COFF
// section, that isn't actually an error. The image can be launched
// alright, only image protection cannot be applied to it fully.
//
// One example that elicits this is (some) Linux kernels (with the EFI stub
// of course).
//
DEBUG ((DEBUG_WARN, "!!!!!!!! ProtectUefiImageCommon - CodeSegmentCount is 0 !!!!!!!!\n"));
PdbPointer = PeCoffLoaderGetPdbPointer ((VOID *)(UINTN)ImageAddress);
if (PdbPointer != NULL) {
DEBUG ((DEBUG_WARN, "!!!!!!!! Image - %a !!!!!!!!\n", PdbPointer));
}
goto Finish;
}
//
// Final
//
SortImageRecordCodeSection (ImageRecord);
//
// Check overlap all section in ImageBase/Size
//
if (!IsImageRecordCodeSectionValid (ImageRecord)) {
DEBUG ((DEBUG_ERROR, "IsImageRecordCodeSectionValid - FAIL\n"));
goto Finish;
}
//
// Round up the ImageSize, some CPU arch may return EFI_UNSUPPORTED if ImageSize is not aligned.
// Given that the loader always allocates full pages, we know the space after the image is not used.
//
ImageRecord->ImageSize = ALIGN_VALUE (LoadedImage->ImageSize, EFI_PAGE_SIZE);
//
// CPU ARCH present. Update memory attribute directly.
//
SetUefiImageProtectionAttributes (ImageRecord);
//
// Record the image record in the list so we can undo the protections later
//
InsertTailList (&mProtectedImageRecordList, &ImageRecord->Link);
Finish:
return;
}
/**
Unprotect UEFI image.
@param[in] LoadedImage The loaded image protocol
@param[in] LoadedImageDevicePath The loaded image device path protocol
**/
VOID
UnprotectUefiImage (
IN EFI_LOADED_IMAGE_PROTOCOL *LoadedImage,
IN EFI_DEVICE_PATH_PROTOCOL *LoadedImageDevicePath
)
{
IMAGE_PROPERTIES_RECORD *ImageRecord;
LIST_ENTRY *ImageRecordLink;
// // MU_CHANGE START Update to use memory protection settings HOB
// if (PcdGet32(PcdImageProtectionPolicy) != 0) {
if (gDxeMps.ImageProtectionPolicy.Data) {
// MU_CHANGE END
for (ImageRecordLink = mProtectedImageRecordList.ForwardLink;
ImageRecordLink != &mProtectedImageRecordList;
ImageRecordLink = ImageRecordLink->ForwardLink)
{
ImageRecord = CR (
ImageRecordLink,
IMAGE_PROPERTIES_RECORD,
Link,
IMAGE_PROPERTIES_RECORD_SIGNATURE
);
if (ImageRecord->ImageBase == (EFI_PHYSICAL_ADDRESS)(UINTN)LoadedImage->ImageBase) {
SetUefiImageMemoryAttributes (
ImageRecord->ImageBase,
ImageRecord->ImageSize,
0
);
FreeImageRecord (ImageRecord);
return;
}
}
}
}
/**
Return the EFI memory permission attribute associated with memory
type 'MemoryType' under the configured DXE memory protection policy.
@param MemoryType Memory type.
**/
// STATIC // MU_CHANGE
UINT64
GetPermissionAttributeForMemoryType (
IN EFI_MEMORY_TYPE MemoryType
)
{
// MU_CHANGE START Update to use memory protection settings HOB
// UINT64 TestBit;
// if ((UINT32)MemoryType >= MEMORY_TYPE_OS_RESERVED_MIN) {
// TestBit = BIT63;
// } else if ((UINT32)MemoryType >= MEMORY_TYPE_OEM_RESERVED_MIN) {
// TestBit = BIT62;
// } else {
// TestBit = LShiftU64 (1, MemoryType);
// }
// if ((gDxeMps.NxProtectionPolicy & TestBit) != 0) { // MU_CHANGE
// return EFI_MEMORY_XP;
// } else {
// return 0;
// }
// Handle code allocations according to the NX_COMPAT DLL flag. If the flag is
// set, the image should update the attributes of code type allocates when it's ready to execute them.
if (IsCodeType (MemoryType) && !IsSystemNxCompatible ()) {
return 0;
} else if (GetDxeMemoryTypeSettingFromBitfield (MemoryType, gDxeMps.NxProtectionPolicy)) {
return EFI_MEMORY_XP;
}
return 0;
// MU_CHANGE END
}
/**
Sort memory map entries based upon PhysicalStart, from low to high.
@param MemoryMap A pointer to the buffer in which firmware places
the current memory map.
@param MemoryMapSize Size, in bytes, of the MemoryMap buffer.
@param DescriptorSize Size, in bytes, of an individual EFI_MEMORY_DESCRIPTOR.
**/
// STATIC // MU_CHANGE
VOID
SortMemoryMap (
IN OUT EFI_MEMORY_DESCRIPTOR *MemoryMap,
IN UINTN MemoryMapSize,
IN UINTN DescriptorSize
)
{
EFI_MEMORY_DESCRIPTOR *MemoryMapEntry;
EFI_MEMORY_DESCRIPTOR *NextMemoryMapEntry;
EFI_MEMORY_DESCRIPTOR *MemoryMapEnd;
EFI_MEMORY_DESCRIPTOR TempMemoryMap;
MemoryMapEntry = MemoryMap;
NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize);
MemoryMapEnd = (EFI_MEMORY_DESCRIPTOR *)((UINT8 *)MemoryMap + MemoryMapSize);
while (MemoryMapEntry < MemoryMapEnd) {
while (NextMemoryMapEntry < MemoryMapEnd) {
if (MemoryMapEntry->PhysicalStart > NextMemoryMapEntry->PhysicalStart) {
CopyMem (&TempMemoryMap, MemoryMapEntry, sizeof (EFI_MEMORY_DESCRIPTOR));
CopyMem (MemoryMapEntry, NextMemoryMapEntry, sizeof (EFI_MEMORY_DESCRIPTOR));
CopyMem (NextMemoryMapEntry, &TempMemoryMap, sizeof (EFI_MEMORY_DESCRIPTOR));
}
NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (NextMemoryMapEntry, DescriptorSize);
}
MemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize);
NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize);
}
}
/**
Merge adjacent memory map entries if they use the same memory protection policy
@param[in, out] MemoryMap A pointer to the buffer in which firmware places
the current memory map.
@param[in, out] MemoryMapSize A pointer to the size, in bytes, of the
MemoryMap buffer. On input, this is the size of
the current memory map. On output,
it is the size of new memory map after merge.
@param[in] DescriptorSize Size, in bytes, of an individual EFI_MEMORY_DESCRIPTOR.
**/
// STATIC // MU_CHANGE
VOID
MergeMemoryMapForProtectionPolicy (
IN OUT EFI_MEMORY_DESCRIPTOR *MemoryMap,
IN OUT UINTN *MemoryMapSize,
IN UINTN DescriptorSize
)
{
EFI_MEMORY_DESCRIPTOR *MemoryMapEntry;
EFI_MEMORY_DESCRIPTOR *MemoryMapEnd;
UINT64 MemoryBlockLength;
EFI_MEMORY_DESCRIPTOR *NewMemoryMapEntry;
EFI_MEMORY_DESCRIPTOR *NextMemoryMapEntry;
UINT64 Attributes;
SortMemoryMap (MemoryMap, *MemoryMapSize, DescriptorSize);
MemoryMapEntry = MemoryMap;
NewMemoryMapEntry = MemoryMap;
MemoryMapEnd = (EFI_MEMORY_DESCRIPTOR *)((UINT8 *)MemoryMap + *MemoryMapSize);
while ((UINTN)MemoryMapEntry < (UINTN)MemoryMapEnd) {
CopyMem (NewMemoryMapEntry, MemoryMapEntry, sizeof (EFI_MEMORY_DESCRIPTOR));
NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize);
do {
MemoryBlockLength = (UINT64)(EFI_PAGES_TO_SIZE ((UINTN)MemoryMapEntry->NumberOfPages));
Attributes = GetPermissionAttributeForMemoryType (MemoryMapEntry->Type);
if (((UINTN)NextMemoryMapEntry < (UINTN)MemoryMapEnd) &&
(Attributes == GetPermissionAttributeForMemoryType (NextMemoryMapEntry->Type)) &&
((MemoryMapEntry->PhysicalStart + MemoryBlockLength) == NextMemoryMapEntry->PhysicalStart))
{
MemoryMapEntry->NumberOfPages += NextMemoryMapEntry->NumberOfPages;
if (NewMemoryMapEntry != MemoryMapEntry) {
NewMemoryMapEntry->NumberOfPages += NextMemoryMapEntry->NumberOfPages;
}
NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (NextMemoryMapEntry, DescriptorSize);
continue;
} else {
MemoryMapEntry = PREVIOUS_MEMORY_DESCRIPTOR (NextMemoryMapEntry, DescriptorSize);
break;
}
} while (TRUE);
MemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize);
NewMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (NewMemoryMapEntry, DescriptorSize);
}
*MemoryMapSize = (UINTN)NewMemoryMapEntry - (UINTN)MemoryMap;
return;
}
/**
Remove exec permissions from all regions whose type is identified by
the Dxe NX Protection Policy. // MU_CHANGE
**/
STATIC
VOID
InitializeDxeNxMemoryProtectionPolicy (
VOID
)
{
UINTN MemoryMapSize;
UINTN MapKey;
UINTN DescriptorSize;
UINT32 DescriptorVersion;
EFI_MEMORY_DESCRIPTOR *MemoryMap;
EFI_MEMORY_DESCRIPTOR *MemoryMapEntry;
EFI_MEMORY_DESCRIPTOR *MemoryMapEnd;
EFI_STATUS Status;
UINT64 Attributes;
LIST_ENTRY *Link;
EFI_GCD_MAP_ENTRY *Entry;
EFI_PEI_HOB_POINTERS Hob;
EFI_HOB_MEMORY_ALLOCATION *MemoryHob;
EFI_PHYSICAL_ADDRESS StackBase;
//
// Get the EFI memory map.
//
MemoryMapSize = 0;
MemoryMap = NULL;
Status = gBS->GetMemoryMap (
&MemoryMapSize,
MemoryMap,
&MapKey,
&DescriptorSize,
&DescriptorVersion
);
ASSERT (Status == EFI_BUFFER_TOO_SMALL);
do {
MemoryMap = (EFI_MEMORY_DESCRIPTOR *)AllocatePool (MemoryMapSize);
// MU_CHANGE [BEGIN] - CodeQL change
if (MemoryMap == NULL) {
ASSERT (MemoryMap != NULL);
return;
}
// MU_CHANGE [END] - CodeQL change
Status = gBS->GetMemoryMap (
&MemoryMapSize,
MemoryMap,
&MapKey,
&DescriptorSize,
&DescriptorVersion
);
if (EFI_ERROR (Status)) {
FreePool (MemoryMap);
}
} while (Status == EFI_BUFFER_TOO_SMALL);
ASSERT_EFI_ERROR (Status);
StackBase = 0;
// MU_CHANGE START Update to use memory protection settings HOB
// if (PcdGetBool (PcdCpuStackGuard)) {
if (gDxeMps.CpuStackGuard) {
// MU_CHANGE END
//
// Get the base of stack from Hob.
//
Hob.Raw = GetHobList ();
while ((Hob.Raw = GetNextHob (EFI_HOB_TYPE_MEMORY_ALLOCATION, Hob.Raw)) != NULL) {
MemoryHob = Hob.MemoryAllocation;
if (CompareGuid (&gEfiHobMemoryAllocStackGuid, &MemoryHob->AllocDescriptor.Name)) {
DEBUG ((
DEBUG_INFO,
"%a: StackBase = 0x%016lx StackSize = 0x%016lx\n",
__FUNCTION__,
MemoryHob->AllocDescriptor.MemoryBaseAddress,
MemoryHob->AllocDescriptor.MemoryLength
));
StackBase = MemoryHob->AllocDescriptor.MemoryBaseAddress;
//
// Ensure the base of the stack is page-size aligned.
//
ASSERT ((StackBase & EFI_PAGE_MASK) == 0);
break;
}
Hob.Raw = GET_NEXT_HOB (Hob);
}
//
// Ensure the base of stack can be found from Hob when stack guard is
// enabled.
//
ASSERT (StackBase != 0);
}
DEBUG ((
DEBUG_INFO,
"%a: applying strict permissions to active memory regions\n",
__FUNCTION__
));
MergeMemoryMapForProtectionPolicy (MemoryMap, &MemoryMapSize, DescriptorSize);
MemoryMapEntry = MemoryMap;
MemoryMapEnd = (EFI_MEMORY_DESCRIPTOR *)((UINT8 *)MemoryMap + MemoryMapSize);
while ((UINTN)MemoryMapEntry < (UINTN)MemoryMapEnd) {
Attributes = GetPermissionAttributeForMemoryType (MemoryMapEntry->Type);
if (Attributes != 0) {
SetUefiImageMemoryAttributes (
MemoryMapEntry->PhysicalStart,
LShiftU64 (MemoryMapEntry->NumberOfPages, EFI_PAGE_SHIFT),
Attributes
);
//
// Add EFI_MEMORY_RP attribute for page 0 if NULL pointer detection is
// enabled.
//
// MU_CHANGE START: We Enable NULL detection via the function EnableNullDetection
// if (MemoryMapEntry->PhysicalStart == 0 &&
// // PcdGet8 (PcdNullPointerDetectionPropertyMask) != 0) {
// ASSERT (MemoryMapEntry->NumberOfPages > 0);
// SetUefiImageMemoryAttributes (
// 0,
// EFI_PAGES_TO_SIZE (1),
// EFI_MEMORY_RP | Attributes);
// }
// MU_CHANGE END
//
// Add EFI_MEMORY_RP attribute for the first page of the stack if stack
// guard is enabled.
//
if ((StackBase != 0) &&
((StackBase >= MemoryMapEntry->PhysicalStart) &&
(StackBase < MemoryMapEntry->PhysicalStart +
LShiftU64 (MemoryMapEntry->NumberOfPages, EFI_PAGE_SHIFT))) &&
// MU_CHANGE START Update to use memory protection settings HOB
// PcdGetBool (PcdCpuStackGuard)) {
gDxeMps.CpuStackGuard)
{
// MU_CHANGE END
SetUefiImageMemoryAttributes (
StackBase,
EFI_PAGES_TO_SIZE (1),
EFI_MEMORY_RP | Attributes
);
}
}
MemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize);
}
FreePool (MemoryMap);