Re: [edk2-devel] [PATCH v5 02/28] MdeModulePkg: Define SetMemoryProtectionsLib and GetMemoryProtectionsLib

["Laszlo Ersek" <lersek@redhat.com>]

On 10/9/23 02:07, Taylor Beebe wrote:
> SetMemoryProtectionsLib is a PEIM which allows platforms to
> apply memory protection settings to the current boot.
> 
> GetMemoryProtectionsLib has DXE and MM implementations to allow
> platforms to query the current memory protection settings via a
> global variable populated by the library Implementations.
> 
> The global variable is a union of the MM and DXE settings. the
> DXE struct is only valid in a DXE module and the MM struct is
> only valid in an SMM or Stanalone MM module.
> 
> Signed-off-by: Taylor Beebe <taylor.d.beebe@gmail.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Liming Gao <gaoliming@byosoft.com.cn>
> ---
>  MdeModulePkg/Include/Library/GetMemoryProtectionsLib.h |  83 +++++++++++
>  MdeModulePkg/Include/Library/SetMemoryProtectionsLib.h | 152 ++++++++++++++++++++
>  MdeModulePkg/MdeModulePkg.dec                          |   8 ++
>  3 files changed, 243 insertions(+)
> 
> diff --git a/MdeModulePkg/Include/Library/GetMemoryProtectionsLib.h b/MdeModulePkg/Include/Library/GetMemoryProtectionsLib.h
> new file mode 100644
> index 000000000000..c8f7084e9c80
> --- /dev/null
> +++ b/MdeModulePkg/Include/Library/GetMemoryProtectionsLib.h
> @@ -0,0 +1,83 @@
> +/** @file
> +Library for accessing the platform memory protection settings.
> +
> +Copyright (c) Microsoft Corporation.
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#ifndef GET_MEMORY_PROTECTION_SETTINGS_LIB_H_
> +#define GET_MEMORY_PROTECTION_SETTINGS_LIB_H_
> +
> +#include <Library/BaseMemoryLib.h>
> +#include <Guid/MemoryProtectionSettings.h>
> +
> +#pragma pack(1)
> +
> +typedef union {
> +  DXE_MEMORY_PROTECTION_SETTINGS    Dxe;
> +  MM_MEMORY_PROTECTION_SETTINGS     Mm;
> +} MEMORY_PROTECTION_SETTINGS_UNION;
> +
> +#pragma pack()
> +
> +// The global used to access current Memory Protection Settings
> +extern MEMORY_PROTECTION_SETTINGS_UNION  gMps;
> +
> +#define MPS_IS_DXE_SIGNATURE_VALID  (gMps.Dxe.Signature == DXE_MEMORY_PROTECTION_SIGNATURE)
> +#define MPS_IS_MM_SIGNATURE_VALID   (gMps.Mm.Signature == MM_MEMORY_PROTECTION_SIGNATURE)
> +
> +#define IS_DXE_PAGE_GUARD_ACTIVE  (MPS_IS_DXE_SIGNATURE_VALID                                                     &&  \
> +                                  !IsZeroBuffer (&gMps.Dxe.PageGuard.EnabledForType, MPS_MEMORY_TYPE_BUFFER_SIZE) &&  \
> +                                  gMps.Dxe.HeapGuard.PageGuardEnabled)
> +
> +#define IS_DXE_POOL_GUARD_ACTIVE  (MPS_IS_DXE_SIGNATURE_VALID                                                     &&  \
> +                                  !IsZeroBuffer (&gMps.Dxe.PoolGuard.EnabledForType, MPS_MEMORY_TYPE_BUFFER_SIZE) &&  \
> +                                  gMps.Dxe.HeapGuard.PoolGuardEnabled)
> +
> +#define IS_DXE_EXECUTION_PROTECTION_ACTIVE  (MPS_IS_DXE_SIGNATURE_VALID                                           &&  \
> +                                            !IsZeroBuffer (&gMps.Dxe.ExecutionProtection.EnabledForType, MPS_MEMORY_TYPE_BUFFER_SIZE))
> +
> +#define IS_DXE_IMAGE_PROTECTION_ACTIVE  (MPS_IS_DXE_SIGNATURE_VALID                         &&  \
> +                                        (gMps.Dxe.ImageProtection.ProtectImageFromFv        ||  \
> +                                         gMps.Dxe.ImageProtection.ProtectImageFromUnknown))
> +
> +#define IS_DXE_MEMORY_PROTECTION_ACTIVE  (MPS_IS_DXE_SIGNATURE_VALID                  &&  \
> +                                         (IS_DXE_PAGE_GUARD_ACTIVE                    ||  \
> +                                          IS_DXE_POOL_GUARD_ACTIVE                    ||  \
> +                                          IS_DXE_EXECUTION_PROTECTION_ACTIVE          ||  \
> +                                          IS_DXE_IMAGE_PROTECTION_ACTIVE              ||  \
> +                                          gMps.Dxe.CpuStackGuardEnabled               ||  \
> +                                          gMps.Dxe.StackExecutionProtectionEnabled    ||  \
> +                                          gMps.Dxe.NullPointerDetection.Enabled       ||  \
> +                                          gMps.Dxe.HeapGuard.FreedMemoryGuardEnabled))
> +
> +#define IS_MM_PAGE_GUARD_ACTIVE  (MPS_IS_MM_SIGNATURE_VALID                                                       &&  \
> +                                   gMps.Mm.HeapGuard.PageGuardEnabled                                             &&  \
> +                                   !IsZeroBuffer (&gMps.Mm.PageGuard.EnabledForType, MPS_MEMORY_TYPE_BUFFER_SIZE))
> +
> +#define IS_MM_POOL_GUARD_ACTIVE  (MPS_IS_MM_SIGNATURE_VALID                                                       &&  \
> +                                  gMps.Mm.HeapGuard.PoolGuardEnabled                                              &&  \
> +                                  !IsZeroBuffer (&gMps.Mm.PoolGuard.EnabledForType, MPS_MEMORY_TYPE_BUFFER_SIZE))
> +
> +#define IS_MM_MEMORY_PROTECTION_ACTIVE  (MPS_IS_MM_SIGNATURE_VALID              &&  \
> +                                        (IS_MM_PAGE_GUARD_ACTIVE                ||  \
> +                                         IS_MM_POOL_GUARD_ACTIVE                ||  \
> +                                         gMps.Mm.NullPointerDetection.Enabled));
> +
> +/**
> +  Populates gMps global. This function is invoked by the library constructor and only needs to be
> +  called if library contructors have not yet been invoked.
> +
> +  @retval EFI_SUCCESS       gMps global was populated.
> +  @retval EFI_NOT_FOUND     The gMemoryProtectionSettingsGuid HOB was not found.
> +  @retval EFI_ABORTED       The version number of the DXE or MM memory protection settings was invalid.
> +  @retval EFI_UNSUPPORTED   NULL implementation called.
> +**/
> +EFI_STATUS
> +EFIAPI
> +PopulateMpsGlobal (
> +  VOID
> +  );
> +
> +#endif
> diff --git a/MdeModulePkg/Include/Library/SetMemoryProtectionsLib.h b/MdeModulePkg/Include/Library/SetMemoryProtectionsLib.h
> new file mode 100644
> index 000000000000..023c987c3c7e
> --- /dev/null
> +++ b/MdeModulePkg/Include/Library/SetMemoryProtectionsLib.h
> @@ -0,0 +1,152 @@
> +/** @file
> +Library for creating the MM and DXE memory protection HOB entries.
> +
> +Copyright (c) Microsoft Corporation.
> +SPDX-License-Identifier: BSD-2-Clause-Patent
> +**/
> +
> +#ifndef SET_MEMORY_PROTECTION_SETTINGS_LIB_H_
> +#define SET_MEMORY_PROTECTION_SETTINGS_LIB_H_
> +
> +#include <Guid/MemoryProtectionSettings.h>
> +
> +typedef struct {
> +  CHAR8                             *Name;
> +  CHAR8                             *Description;
> +  DXE_MEMORY_PROTECTION_SETTINGS    Settings;
> +} DXE_MEMORY_PROTECTION_PROFILES;
> +
> +typedef enum {
> +  DxeMemoryProtectionSettingsPcd,
> +  DxeMemoryProtectionSettingsMax
> +} DXE_MEMORY_PROTECTION_PROFILE_INDEX;
> +
> +typedef struct {
> +  CHAR8                            *Name;
> +  CHAR8                            *Description;
> +  MM_MEMORY_PROTECTION_SETTINGS    Settings;
> +} MM_MEMORY_PROTECTION_PROFILES;
> +
> +typedef enum {
> +  MmMemoryProtectionSettingsPcd,
> +  MmMemoryProtectionSettingsMax
> +} MM_MEMORY_PROTECTION_PROFILE_INDEX;
> +
> +extern DXE_MEMORY_PROTECTION_PROFILES  DxeMemoryProtectionProfiles[DxeMemoryProtectionSettingsMax];
> +extern MM_MEMORY_PROTECTION_PROFILES   MmMemoryProtectionProfiles[MmMemoryProtectionSettingsMax];

These names aren't right; global variable names minimally need to start
with "m" (for "module"), or if the thing they refer to is
firmware-global, they should start with "g".

Compare: "gBS", from
"MdePkg/Include/Library/UefiBootServicesTableLib.h". Each module using
UefiBootServicesTableLib will have a copy of that pointer, but it will
point to the same thing.

Laszlo

> +
> +/**
> +  Prevent further changes to the memory protection settings via this
> +  library API.
> +
> +  @retval EFI_SUCCESS           The memory protection settings are locked.
> +  @retval EFI_ABORTED           Unable to get/create the memory protection settings.
> +  @retval EFI_UNSUPPORTED       NULL implementation called.
> +**/
> +EFI_STATUS
> +EFIAPI
> +LockMemoryProtectionSettings (
> +  VOID
> +  );
> +
> +/**
> +  Sets the DXE memory protection settings. If DxeMps is NULL, the settings will be set based
> +  on ProfileIndex.
> +
> +  @param[in] DxeMps        Pointer to the memory protection settings to publish. If NULL, the
> +                           settings will be created based on ProfileIndex.
> +  @param[in] ProfileIndex  The index of the memory protection profile to use if DxeMps is NULL.
> +
> +  @retval EFI_SUCCESS           The memory protection HOB was successfully created.
> +  @retval EFI_INVALID_PARAMETER The ProfileIndex was invalid or the version number of the
> +                                input DxeMps was not equal to the version currently present
> +                                in the settings.
> +  @retval EFI_ABORTED           Unable to get/create the memory protection settings.
> +  @retval EFI_ACCESS_DENIED     The memory protection settings are locked.
> +  @retval EFI_UNSUPPORTED       NULL implementation called.
> +**/
> +EFI_STATUS
> +EFIAPI
> +SetDxeMemoryProtectionSettings (
> +  IN DXE_MEMORY_PROTECTION_SETTINGS       *DxeMps OPTIONAL,
> +  IN DXE_MEMORY_PROTECTION_PROFILE_INDEX  ProfileIndex
> +  );
> +
> +/**
> +  Sets the MM memory protection HOB entry. If MmMps is NULL, the settings will be set based
> +  on ProfileIndex.
> +
> +  @param[in] MmMps         Pointer to the memory protection settings to publish. If NULL, the
> +                           settings will be created based on ProfileIndex.
> +  @param[in] ProfileIndex  The index of the memory protection profile to use if MmMps is NULL.
> +
> +  @retval EFI_SUCCESS           The memory protection HOB was successfully created.
> +  @retval EFI_OUT_OF_RESOURCES  There was insufficient memory to create the HOB.
> +  @retval EFI_INVALID_PARAMETER The ProfileIndex was invalid or the version number of the
> +                                input MmMps was not equal to the version currently present
> +                                in the settings.
> +  @retval EFI_ABORTED           Unable to get/create the memory protection settings.
> +  @retval EFI_ACCESS_DENIED     The memory protection settings are locked.
> +  @retval EFI_UNSUPPORTED       NULL implementation called.
> +**/
> +EFI_STATUS
> +EFIAPI
> +SetMmMemoryProtectionSettings (
> +  IN MM_MEMORY_PROTECTION_SETTINGS       *MmMps OPTIONAL,
> +  IN MM_MEMORY_PROTECTION_PROFILE_INDEX  ProfileIndex
> +  );
> +
> +/**
> +  Copies the current memory protection settings into the input buffer.
> +
> +  NOTE: The returned settings may not be the final settings used by the
> +        platform on this boot. Unless LockMemoryProtectionSettings() has
> +        been called, settings may be modified by drivers until DXE handoff.
> +
> +  @param[out] Mps  The memory protection settings pointer to populate.
> +
> +  @retval EFI_SUCCESS           The memory protection settings were copied
> +                                into the input buffer.
> +  @retval EFI_INVALID_PARAMETER Mps was NULL.
> +  @retval EFI_ABORTED           Unable to get/create the memory protection settings.
> +  @retval EFI_UNSUPPORTED       NULL implementation called.
> +**/
> +EFI_STATUS
> +EFIAPI
> +GetCurrentMemoryProtectionSettings (
> +  OUT MEMORY_PROTECTION_SETTINGS  *Mps
> +  );
> +
> +/**
> +  Returns TRUE any form of DXE memory protection is currently active.
> +
> +  NOTE: The returned value may reflect the final settings used by the
> +        platform on this boot. Unless LockMemoryProtectionSettings() has
> +        been called, settings may be modified by drivers until DXE handoff.
> +
> +  @retval TRUE   DXE Memory protection is active.
> +  @retval FALSE  DXE Memory protection is not active.
> +**/
> +BOOLEAN
> +EFIAPI
> +IsDxeMemoryProtectionActive (
> +  VOID
> +  );
> +
> +/**
> +  Returns TRUE any form of MM memory protection is currently active.
> +
> +  NOTE: The returned value may reflect the final settings used by the
> +        platform on this boot. Unless LockMemoryProtectionSettings() has
> +        been called, settings may be modified by drivers until DXE handoff.
> +
> +  @retval TRUE   MM Memory protection is active.
> +  @retval FALSE  MM Memory protection is not active.
> +**/
> +BOOLEAN
> +EFIAPI
> +IsMmMemoryProtectionActive (
> +  VOID
> +  );
> +
> +#endif
> diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
> index 5e1a0388bed3..6ad0902a1bff 100644
> --- a/MdeModulePkg/MdeModulePkg.dec
> +++ b/MdeModulePkg/MdeModulePkg.dec
> @@ -164,6 +164,14 @@ [LibraryClasses]
>    #
>    VariableFlashInfoLib|Include/Library/VariableFlashInfoLib.h
>  
> +  ## @libraryclass Provides a global for consuming memory protection settings
> +  #
> +  GetMemoryProtectionsLib|Include/Library/GetMemoryProtectionsLib.h
> +
> +  ## @libraryclass Library for creating the memory protection settings HOB
> +  #
> +  SetMemoryProtectionsLib|Include/Library/SetMemoryProtectionsLib.h
> +
>  [Guids]
>    ## MdeModule package token space guid
>    # Include/Guid/MdeModulePkgTokenSpace.h



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