On Mon, Mar 13, 2023 at 18:16:59 +0100, Ard Biesheuvel wrote:
> Deal with DRAM memory potentially being mapped with non-executable
> permissions, by mapping the DXE core code sections explicitly before
> launch.
Could you add a note about why LoadPeCoffImage/LoadDxeCoreFromFfsFile
are made private?
/
Leif
> Signed-off-by: Ard Biesheuvel <a...@kernel.org>
> ---
> EmbeddedPkg/Include/Library/PrePiLib.h | 16 ------
> EmbeddedPkg/Library/PrePiLib/Arm/RemapDxeCore.c | 51 ++++++++++++++++++++
> EmbeddedPkg/Library/PrePiLib/PrePi.h | 13 +++++
> EmbeddedPkg/Library/PrePiLib/PrePiLib.c | 4 ++
> EmbeddedPkg/Library/PrePiLib/PrePiLib.inf | 12 +++++
> EmbeddedPkg/Library/PrePiLib/X86/RemapDxeCore.c | 23 +++++++++
> 6 files changed, 103 insertions(+), 16 deletions(-)
>
> diff --git a/EmbeddedPkg/Include/Library/PrePiLib.h
> b/EmbeddedPkg/Include/Library/PrePiLib.h
> index 93a9115eac2d..14f2bbc38dae 100644
> --- a/EmbeddedPkg/Include/Library/PrePiLib.h
> +++ b/EmbeddedPkg/Include/Library/PrePiLib.h
> @@ -758,22 +758,6 @@ AllocateAlignedPages (
> IN UINTN Alignment
> );
>
> -EFI_STATUS
> -EFIAPI
> -LoadPeCoffImage (
> - IN VOID *PeCoffImage,
> - OUT EFI_PHYSICAL_ADDRESS *ImageAddress,
> - OUT UINT64 *ImageSize,
> - OUT EFI_PHYSICAL_ADDRESS *EntryPoint
> - );
> -
> -EFI_STATUS
> -EFIAPI
> -LoadDxeCoreFromFfsFile (
> - IN EFI_PEI_FILE_HANDLE FileHandle,
> - IN UINTN StackSize
> - );
> -
> EFI_STATUS
> EFIAPI
> LoadDxeCoreFromFv (
> diff --git a/EmbeddedPkg/Library/PrePiLib/Arm/RemapDxeCore.c
> b/EmbeddedPkg/Library/PrePiLib/Arm/RemapDxeCore.c
> new file mode 100644
> index 000000000000..40d4ed9d77bd
> --- /dev/null
> +++ b/EmbeddedPkg/Library/PrePiLib/Arm/RemapDxeCore.c
> @@ -0,0 +1,51 @@
> +/** @file
> + Copyright (c) 2023, Google LLC. All rights reserved.<BR>
> +
> + SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "PrePi.h"
> +
> +#include <Library/ArmMmuLib.h>
> +
> +/**
> + Remap the code section of the DXE core with the read-only and executable
> + permissions.
> +
> + @param ImageContext The image context describing the loaded PE/COFF
> image
> +
> +**/
> +VOID
> +EFIAPI
> +RemapDxeCore (
> + IN CONST PE_COFF_LOADER_IMAGE_CONTEXT *ImageContext
> + )
> +{
> + EFI_IMAGE_OPTIONAL_HEADER_PTR_UNION Hdr;
> + EFI_IMAGE_SECTION_HEADER *Section;
> + UINTN Index;
> +
> + Hdr.Union = (EFI_IMAGE_OPTIONAL_HEADER_UNION *)((UINT8
> *)ImageContext->Handle +
> +
> ImageContext->PeCoffHeaderOffset);
> + ASSERT (Hdr.Pe32->Signature == EFI_IMAGE_NT_SIGNATURE);
> +
> + Section = (EFI_IMAGE_SECTION_HEADER *)((UINT8 *)Hdr.Union + sizeof
> (UINT32) +
> + sizeof (EFI_IMAGE_FILE_HEADER) +
> +
> Hdr.Pe32->FileHeader.SizeOfOptionalHeader
> + );
> +
> + for (Index = 0; Index < Hdr.Pe32->FileHeader.NumberOfSections; Index++) {
> + if ((Section[Index].Characteristics & EFI_IMAGE_SCN_CNT_CODE) != 0) {
> + ArmSetMemoryRegionReadOnly (
> + (UINTN)(ImageContext->ImageAddress + Section[Index].VirtualAddress),
> + Section[Index].Misc.VirtualSize
> + );
> +
> + ArmClearMemoryRegionNoExec (
> + (UINTN)(ImageContext->ImageAddress + Section[Index].VirtualAddress),
> + Section[Index].Misc.VirtualSize
> + );
> + }
> + }
> +}
> diff --git a/EmbeddedPkg/Library/PrePiLib/PrePi.h
> b/EmbeddedPkg/Library/PrePiLib/PrePi.h
> index a00c946512f4..a0f8837d1d37 100644
> --- a/EmbeddedPkg/Library/PrePiLib/PrePi.h
> +++ b/EmbeddedPkg/Library/PrePiLib/PrePi.h
> @@ -37,4 +37,17 @@
> #define GET_GUID_HOB_DATA(GuidHob) ((VOID *) (((UINT8 *)
> &((GuidHob)->Name)) + sizeof (EFI_GUID)))
> #define GET_GUID_HOB_DATA_SIZE(GuidHob) (((GuidHob)->Header).HobLength -
> sizeof (EFI_HOB_GUID_TYPE))
>
> +/**
> + Remap the code section of the DXE core with the read-only and executable
> + permissions.
> +
> + @param ImageContext The image context describing the loaded PE/COFF
> image
> +
> +**/
> +VOID
> +EFIAPI
> +RemapDxeCore (
> + IN CONST PE_COFF_LOADER_IMAGE_CONTEXT *ImageContext
> + );
> +
> #endif
> diff --git a/EmbeddedPkg/Library/PrePiLib/PrePiLib.c
> b/EmbeddedPkg/Library/PrePiLib/PrePiLib.c
> index 3cf866dab248..188ad5c518a8 100644
> --- a/EmbeddedPkg/Library/PrePiLib/PrePiLib.c
> +++ b/EmbeddedPkg/Library/PrePiLib/PrePiLib.c
> @@ -54,6 +54,7 @@ AllocateCodePages (
> return NULL;
> }
>
> +STATIC
> EFI_STATUS
> EFIAPI
> LoadPeCoffImage (
> @@ -105,6 +106,8 @@ LoadPeCoffImage (
> //
> InvalidateInstructionCacheRange ((VOID *)(UINTN)*ImageAddress,
> (UINTN)*ImageSize);
>
> + RemapDxeCore (&ImageContext);
> +
> return Status;
> }
>
> @@ -114,6 +117,7 @@ VOID
> IN VOID *HobStart
> );
>
> +STATIC
> EFI_STATUS
> EFIAPI
> LoadDxeCoreFromFfsFile (
> diff --git a/EmbeddedPkg/Library/PrePiLib/PrePiLib.inf
> b/EmbeddedPkg/Library/PrePiLib/PrePiLib.inf
> index 090bfe888f52..2df5928c51d5 100644
> --- a/EmbeddedPkg/Library/PrePiLib/PrePiLib.inf
> +++ b/EmbeddedPkg/Library/PrePiLib/PrePiLib.inf
> @@ -31,11 +31,20 @@ [Sources.common]
> FwVol.c
> PrePiLib.c
>
> +[Sources.X64, Sources.IA32]
> + X86/RemapDxeCore.c
> +
> +[Sources.AARCH64, Sources.ARM]
> + Arm/RemapDxeCore.c
> +
> [Packages]
> MdePkg/MdePkg.dec
> EmbeddedPkg/EmbeddedPkg.dec
> MdeModulePkg/MdeModulePkg.dec
>
> +[Packages.ARM, Packages.AARCH64]
> + ArmPkg/ArmPkg.dec
> +
> [LibraryClasses]
> BaseLib
> DebugLib
> @@ -50,6 +59,9 @@ [LibraryClasses]
> PerformanceLib
> HobLib
>
> +[LibraryClasses.ARM, LibraryClasses.AARCH64]
> + ArmMmuLib
> +
> [Guids]
> gEfiMemoryTypeInformationGuid
>
> diff --git a/EmbeddedPkg/Library/PrePiLib/X86/RemapDxeCore.c
> b/EmbeddedPkg/Library/PrePiLib/X86/RemapDxeCore.c
> new file mode 100644
> index 000000000000..1899c050fdec
> --- /dev/null
> +++ b/EmbeddedPkg/Library/PrePiLib/X86/RemapDxeCore.c
> @@ -0,0 +1,23 @@
> +/** @file
> + Copyright (c) 2023, Google LLC. All rights reserved.<BR>
> +
> + SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include "PrePi.h"
> +
> +/**
> + Remap the code section of the DXE core with the read-only and executable
> + permissions.
> +
> + @param ImageContext The image context describing the loaded PE/COFF
> image
> +
> +**/
> +VOID
> +EFIAPI
> +RemapDxeCore (
> + IN CONST PE_COFF_LOADER_IMAGE_CONTEXT *ImageContext
> + )
> +{
> +}
> --
> 2.39.2
>
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