[edk2-devel] [PATCH v6 09/14] MdeModulePkg: Connect VariablePolicy business logic to VariableServices
Bret Barkelew via groups.io
bret.barkelew=microsoft.com at groups.io
Thu Jul 2 06:40:14 UTC 2020
1. [Dandan]: I see other APIs in the VariablePolicyProtocol are using the APIs in VariablePolicyLib directly, expect this one.
Could we make the IsVariablePolicyEnabled API aligned in protocol and Lib?
This is because of an incongruity between the protocol definition and the library definition. For a simpler interface the library returns a BOOLEAN, but the Protocol returns EFI_STATUS (to align with the majority of Protocol calls). Could update the library to match the protocol, if it’s important, but it would touch a number of places.
- Bret
From: Dandan Bi via groups.io<mailto:dandan.bi=intel.com at groups.io>
Sent: Wednesday, July 1, 2020 7:13 PM
To: devel at edk2.groups.io<mailto:devel at edk2.groups.io>; bret at corthon.com<mailto:bret at corthon.com>
Cc: Wang, Jian J<mailto:jian.j.wang at intel.com>; Wu, Hao A<mailto:hao.a.wu at intel.com>; liming.gao<mailto:liming.gao at intel.com>
Subject: [EXTERNAL] Re: [edk2-devel] [PATCH v6 09/14] MdeModulePkg: Connect VariablePolicy business logic to VariableServices
1 comment inline, please check.
Thanks,
Dandan
> -----Original Message-----
> From: devel at edk2.groups.io <devel at edk2.groups.io> On Behalf Of Bret
> Barkelew
> Sent: Tuesday, June 23, 2020 2:41 PM
> To: devel at edk2.groups.io
> Cc: Wang, Jian J <jian.j.wang at intel.com>; Wu, Hao A <hao.a.wu at intel.com>;
> Gao, Liming <liming.gao at intel.com>
> Subject: [edk2-devel] [PATCH v6 09/14] MdeModulePkg: Connect
> VariablePolicy business logic to VariableServices
>
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.tianocore.org%2Fshow_bug.cgi%3Fid%3D2522&data=02%7C01%7CBret.Barkelew%40microsoft.com%7C3cebf618dafa4cfee99d08d81e2d7eea%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637292528041413678&sdata=MqZbcBcrPmvajnjVnc8Ohmvq1s3u4OaUQB0d1wrdvLw%3D&reserved=0
>
> VariablePolicy is an updated interface to
> replace VarLock and VarCheckProtocol.
>
> Add connective code to publish the VariablePolicy protocol
> and wire it to either the SMM communication interface
> or directly into the VariablePolicyLib business logic.
>
> Cc: Jian J Wang <jian.j.wang at intel.com>
> Cc: Hao A Wu <hao.a.wu at intel.com>
> Cc: Liming Gao <liming.gao at intel.com>
> Cc: Bret Barkelew <brbarkel at microsoft.com>
> Signed-off-by: Bret Barkelew <brbarkel at microsoft.com>
> ---
> MdeModulePkg/Universal/Variable/RuntimeDxe/VariableDxe.c | 53
> ++
> MdeModulePkg/Universal/Variable/RuntimeDxe/VariablePolicySmmDxe.c
> | 642 ++++++++++++++++++++
>
> MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.
> c | 14 +
> MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> | 2 +
> MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf | 3
> +
>
> MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.i
> nf | 10 +
> 6 files changed, 724 insertions(+)
>
> diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableDxe.c
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableDxe.c
> index 7d2b6c8e1fad..d404d4763e54 100644
> --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableDxe.c
> +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableDxe.c
> @@ -5,18 +5,34 @@
> Copyright (C) 2013, Red Hat, Inc.
>
> Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
>
> (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR>
>
> +Copyright (c) Microsoft Corporation.
>
> SPDX-License-Identifier: BSD-2-Clause-Patent
>
>
>
> **/
>
>
>
> #include "Variable.h"
>
>
>
> +#include <Protocol/VariablePolicy.h>
>
> +#include <Library/VariablePolicyLib.h>
>
> +
>
> +EFI_STATUS
>
> +EFIAPI
>
> +ProtocolIsVariablePolicyEnabled (
>
> + OUT BOOLEAN *State
>
> + );
>
> +
>
> EFI_HANDLE mHandle = NULL;
>
> EFI_EVENT mVirtualAddressChangeEvent = NULL;
>
> VOID *mFtwRegistration = NULL;
>
> VOID ***mVarCheckAddressPointer = NULL;
>
> UINTN mVarCheckAddressPointerCount = 0;
>
> EDKII_VARIABLE_LOCK_PROTOCOL mVariableLock =
> { VariableLockRequestToLock };
>
> +EDKII_VARIABLE_POLICY_PROTOCOL mVariablePolicyProtocol =
> { EDKII_VARIABLE_POLICY_PROTOCOL_REVISION,
>
> + DisableVariablePolicy,
>
> + ProtocolIsVariablePolicyEnabled,
>
> + RegisterVariablePolicy,
>
> + DumpVariablePolicy,
>
> + LockVariablePolicy };
>
> EDKII_VAR_CHECK_PROTOCOL mVarCheck =
> { VarCheckRegisterSetVariableCheckHandler,
>
> VarCheckVariablePropertySet,
>
> VarCheckVariablePropertyGet };
>
> @@ -303,6 +319,8 @@ OnReadyToBoot (
> }
>
> }
>
>
>
> + ASSERT_EFI_ERROR (LockVariablePolicy ());
>
> +
>
> gBS->CloseEvent (Event);
>
> }
>
>
>
> @@ -466,6 +484,28 @@ FtwNotificationEvent (
> }
>
>
>
>
>
> +/**
>
> + This API function returns whether or not the policy engine is
>
> + currently being enforced.
>
> +
>
> + @param[out] State Pointer to a return value for whether the policy
> enforcement
>
> + is currently enabled.
>
> +
>
> + @retval EFI_SUCCESS
>
> + @retval Others An error has prevented this command from
> completing.
>
> +
>
> +**/
>
> +EFI_STATUS
>
> +EFIAPI
>
> +ProtocolIsVariablePolicyEnabled (
>
> + OUT BOOLEAN *State
>
> + )
>
> +{
>
> + *State = IsVariablePolicyEnabled ();
>
> + return EFI_SUCCESS;
>
> +}
1. [Dandan]: I see other APIs in the VariablePolicyProtocol are using the APIs in VariablePolicyLib directly, expect this one.
Could we make the IsVariablePolicyEnabled API aligned in protocol and Lib?
>
> +
>
> +
>
> /**
>
> Variable Driver main entry point. The Variable driver places the 4 EFI
>
> runtime services in the EFI System Table and installs arch protocols
>
> @@ -576,6 +616,19 @@ VariableServiceInitialize (
> );
>
> ASSERT_EFI_ERROR (Status);
>
>
>
> + // Register and initialize the VariablePolicy engine.
>
> + Status = InitVariablePolicyLib (VariableServiceGetVariable);
>
> + ASSERT_EFI_ERROR (Status);
>
> + Status = VarCheckRegisterSetVariableCheckHandler (ValidateSetVariable);
>
> + ASSERT_EFI_ERROR (Status);
>
> + Status = gBS->InstallMultipleProtocolInterfaces (
>
> + &mHandle,
>
> + &gEdkiiVariablePolicyProtocolGuid,
>
> + &mVariablePolicyProtocol,
>
> + NULL
>
> + );
>
> + ASSERT_EFI_ERROR (Status);
>
> +
>
> return EFI_SUCCESS;
>
> }
>
>
>
> diff --git
> a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariablePolicySmmDxe.c
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariablePolicySmmDxe.c
> new file mode 100644
> index 000000000000..e2d4cf4cec1a
> --- /dev/null
> +++
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariablePolicySmmDxe.c
> @@ -0,0 +1,642 @@
> +/** @file -- VariablePolicySmmDxe.c
>
> +This protocol allows communication with Variable Policy Engine.
>
> +
>
> +Copyright (c) Microsoft Corporation.
>
> +SPDX-License-Identifier: BSD-2-Clause-Patent
>
> +
>
> +**/
>
> +
>
> +#include <Library/BaseLib.h>
>
> +#include <Library/UefiLib.h>
>
> +#include <Library/DebugLib.h>
>
> +#include <Library/SafeIntLib.h>
>
> +#include <Library/UefiBootServicesTableLib.h>
>
> +#include <Library/BaseMemoryLib.h>
>
> +#include <Library/MemoryAllocationLib.h>
>
> +
>
> +#include <Protocol/VariablePolicy.h>
>
> +#include <Protocol/MmCommunication2.h>
>
> +
>
> +#include <Guid/VarCheckPolicyMmi.h>
>
> +
>
> +#include "Variable.h"
>
> +
>
> +EDKII_VARIABLE_POLICY_PROTOCOL mVariablePolicyProtocol;
>
> +EFI_MM_COMMUNICATION2_PROTOCOL *mMmCommunication;
>
> +
>
> +VOID *mMmCommunicationBuffer;
>
> +UINTN mMmCommunicationBufferSize;
>
> +EFI_LOCK mMmCommunicationLock;
>
> +
>
> +/**
>
> + Internal helper function to consolidate communication method.
>
> +
>
> + @param[in,out] CommBuffer
>
> + @param[in,out] CommSize Size of the CommBuffer.
>
> +
>
> + @retval EFI_STATUS Result from communication method.
>
> +
>
> +**/
>
> +STATIC
>
> +EFI_STATUS
>
> +InternalMmCommunicate (
>
> + IN OUT VOID *CommBuffer,
>
> + IN OUT UINTN *CommSize
>
> + )
>
> +{
>
> + EFI_STATUS Status;
>
> + if (CommBuffer == NULL || CommSize == NULL) {
>
> + return EFI_INVALID_PARAMETER;
>
> + }
>
> + Status = mMmCommunication->Communicate (mMmCommunication,
> CommBuffer, CommBuffer, CommSize);
>
> + return Status;
>
> +}
>
> +
>
> +
>
> +/**
>
> + This API function disables the variable policy enforcement. If it's
>
> + already been called once, will return EFI_ALREADY_STARTED.
>
> +
>
> + @retval EFI_SUCCESS
>
> + @retval EFI_ALREADY_STARTED Has already been called once this boot.
>
> + @retval EFI_WRITE_PROTECTED Interface has been locked until reboot.
>
> + @retval EFI_WRITE_PROTECTED Interface option is disabled by platform
> PCD.
>
> +
>
> +**/
>
> +STATIC
>
> +EFI_STATUS
>
> +EFIAPI
>
> +ProtocolDisableVariablePolicy (
>
> + VOID
>
> + )
>
> +{
>
> + EFI_STATUS Status;
>
> + EFI_MM_COMMUNICATE_HEADER *CommHeader;
>
> + VAR_CHECK_POLICY_COMM_HEADER *PolicyHeader;
>
> + UINTN BufferSize;
>
> +
>
> + // Check the PCD for convenience.
>
> + // This would also be rejected by the lib, but why go to MM if we don't
> have to?
>
> + if (!PcdGetBool (PcdAllowVariablePolicyEnforcementDisable)) {
>
> + return EFI_WRITE_PROTECTED;
>
> + }
>
> +
>
> + AcquireLockOnlyAtBootTime (&mMmCommunicationLock);
>
> +
>
> + // Set up the MM communication.
>
> + BufferSize = mMmCommunicationBufferSize;
>
> + CommHeader = mMmCommunicationBuffer;
>
> + PolicyHeader = (VAR_CHECK_POLICY_COMM_HEADER*)&CommHeader-
> >Data;
>
> + CopyGuid( &CommHeader->HeaderGuid,
> &gVarCheckPolicyLibMmiHandlerGuid );
>
> + CommHeader->MessageLength = BufferSize;
>
> + PolicyHeader->Signature = VAR_CHECK_POLICY_COMM_SIG;
>
> + PolicyHeader->Revision = VAR_CHECK_POLICY_COMM_REVISION;
>
> + PolicyHeader->Command = VAR_CHECK_POLICY_COMMAND_DISABLE;
>
> +
>
> + Status = InternalMmCommunicate (CommHeader, &BufferSize);
>
> + DEBUG(( DEBUG_VERBOSE, "%a - MmCommunication returned %r.\n",
> __FUNCTION__, Status ));
>
> +
>
> + ReleaseLockOnlyAtBootTime (&mMmCommunicationLock);
>
> +
>
> + return (EFI_ERROR( Status )) ? Status : PolicyHeader->Result;
>
> +}
>
> +
>
> +
>
> +/**
>
> + This API function returns whether or not the policy engine is
>
> + currently being enforced.
>
> +
>
> + @param[out] State Pointer to a return value for whether the policy
> enforcement
>
> + is currently enabled.
>
> +
>
> + @retval EFI_SUCCESS
>
> + @retval Others An error has prevented this command from
> completing.
>
> +
>
> +**/
>
> +STATIC
>
> +EFI_STATUS
>
> +EFIAPI
>
> +ProtocolIsVariablePolicyEnabled (
>
> + OUT BOOLEAN *State
>
> + )
>
> +{
>
> + EFI_STATUS Status;
>
> + EFI_MM_COMMUNICATE_HEADER *CommHeader;
>
> + VAR_CHECK_POLICY_COMM_HEADER *PolicyHeader;
>
> + VAR_CHECK_POLICY_COMM_IS_ENABLED_PARAMS *CommandParams;
>
> + UINTN BufferSize;
>
> +
>
> + if (State == NULL) {
>
> + return EFI_INVALID_PARAMETER;
>
> + }
>
> +
>
> + AcquireLockOnlyAtBootTime (&mMmCommunicationLock);
>
> +
>
> + // Set up the MM communication.
>
> + BufferSize = mMmCommunicationBufferSize;
>
> + CommHeader = mMmCommunicationBuffer;
>
> + PolicyHeader = (VAR_CHECK_POLICY_COMM_HEADER*)&CommHeader-
> >Data;
>
> + CommandParams =
> (VAR_CHECK_POLICY_COMM_IS_ENABLED_PARAMS*)(PolicyHeader + 1);
>
> + CopyGuid( &CommHeader->HeaderGuid,
> &gVarCheckPolicyLibMmiHandlerGuid );
>
> + CommHeader->MessageLength = BufferSize;
>
> + PolicyHeader->Signature = VAR_CHECK_POLICY_COMM_SIG;
>
> + PolicyHeader->Revision = VAR_CHECK_POLICY_COMM_REVISION;
>
> + PolicyHeader->Command =
> VAR_CHECK_POLICY_COMMAND_IS_ENABLED;
>
> +
>
> + Status = InternalMmCommunicate (CommHeader, &BufferSize);
>
> + DEBUG(( DEBUG_VERBOSE, "%a - MmCommunication returned %r.\n",
> __FUNCTION__, Status ));
>
> +
>
> + if (!EFI_ERROR( Status )) {
>
> + Status = PolicyHeader->Result;
>
> + *State = CommandParams->State;
>
> + }
>
> +
>
> + ReleaseLockOnlyAtBootTime (&mMmCommunicationLock);
>
> +
>
> + return Status;
>
> +}
>
> +
>
> +
>
> +/**
>
> + This API function validates and registers a new policy with
>
> + the policy enforcement engine.
>
> +
>
> + @param[in] NewPolicy Pointer to the incoming policy structure.
>
> +
>
> + @retval EFI_SUCCESS
>
> + @retval EFI_INVALID_PARAMETER NewPolicy is NULL or is internally
> inconsistent.
>
> + @retval EFI_ALREADY_STARTED An identical matching policy already
> exists.
>
> + @retval EFI_WRITE_PROTECTED The interface has been locked until
> the next reboot.
>
> + @retval EFI_UNSUPPORTED Policy enforcement has been disabled.
> No reason to add more policies.
>
> + @retval EFI_ABORTED A calculation error has prevented this
> function from completing.
>
> + @retval EFI_OUT_OF_RESOURCES Cannot grow the table to hold any
> more policies.
>
> +
>
> +**/
>
> +STATIC
>
> +EFI_STATUS
>
> +EFIAPI
>
> +ProtocolRegisterVariablePolicy (
>
> + IN CONST VARIABLE_POLICY_ENTRY *NewPolicy
>
> + )
>
> +{
>
> + EFI_STATUS Status;
>
> + EFI_MM_COMMUNICATE_HEADER *CommHeader;
>
> + VAR_CHECK_POLICY_COMM_HEADER *PolicyHeader;
>
> + VOID *PolicyBuffer;
>
> + UINTN BufferSize;
>
> + UINTN RequiredSize;
>
> +
>
> + if (NewPolicy == NULL) {
>
> + return EFI_INVALID_PARAMETER;
>
> + }
>
> +
>
> + // First, make sure that the required size does not exceed the capabilities
>
> + // of the MmCommunication buffer.
>
> + RequiredSize = OFFSET_OF(EFI_MM_COMMUNICATE_HEADER, Data) +
> sizeof(VAR_CHECK_POLICY_COMM_HEADER);
>
> + Status = SafeUintnAdd( RequiredSize, NewPolicy->Size, &RequiredSize );
>
> + if (EFI_ERROR( Status ) || RequiredSize > mMmCommunicationBufferSize)
> {
>
> + DEBUG(( DEBUG_ERROR, "%a - Policy too large for buffer! %r, %d > %d
> \n", __FUNCTION__,
>
> + Status, RequiredSize, mMmCommunicationBufferSize ));
>
> + return EFI_OUT_OF_RESOURCES;
>
> + }
>
> +
>
> + AcquireLockOnlyAtBootTime (&mMmCommunicationLock);
>
> +
>
> + // Set up the MM communication.
>
> + BufferSize = mMmCommunicationBufferSize;
>
> + CommHeader = mMmCommunicationBuffer;
>
> + PolicyHeader = (VAR_CHECK_POLICY_COMM_HEADER*)&CommHeader-
> >Data;
>
> + PolicyBuffer = (VOID*)(PolicyHeader + 1);
>
> + CopyGuid( &CommHeader->HeaderGuid,
> &gVarCheckPolicyLibMmiHandlerGuid );
>
> + CommHeader->MessageLength = BufferSize;
>
> + PolicyHeader->Signature = VAR_CHECK_POLICY_COMM_SIG;
>
> + PolicyHeader->Revision = VAR_CHECK_POLICY_COMM_REVISION;
>
> + PolicyHeader->Command = VAR_CHECK_POLICY_COMMAND_REGISTER;
>
> +
>
> + // Copy the policy into place. This copy is safe because we've already
> tested above.
>
> + CopyMem( PolicyBuffer, NewPolicy, NewPolicy->Size );
>
> +
>
> + Status = InternalMmCommunicate (CommHeader, &BufferSize);
>
> + DEBUG(( DEBUG_VERBOSE, "%a - MmCommunication returned %r.\n",
> __FUNCTION__, Status ));
>
> +
>
> + ReleaseLockOnlyAtBootTime (&mMmCommunicationLock);
>
> +
>
> + return (EFI_ERROR( Status )) ? Status : PolicyHeader->Result;
>
> +}
>
> +
>
> +
>
> +/**
>
> + This helper function takes care of the overhead of formatting, sending,
> and interpreting
>
> + the results for a single DumpVariablePolicy request.
>
> +
>
> + @param[in] PageRequested The page of the paginated results from
> MM. 0 for metadata.
>
> + @param[out] TotalSize The total size of the entire buffer. Returned as
> part of metadata.
>
> + @param[out] PageSize The size of the current page being returned.
> Not valid as part of metadata.
>
> + @param[out] HasMore A flag indicating whether there are more
> pages after this one.
>
> + @param[out] Buffer The start of the current page from MM.
>
> +
>
> + @retval EFI_SUCCESS Output params have been updated (either
> metadata or dump page).
>
> + @retval EFI_INVALID_PARAMETER One of the output params is NULL.
>
> + @retval Others Response from MM handler.
>
> +
>
> +**/
>
> +STATIC
>
> +EFI_STATUS
>
> +DumpVariablePolicyHelper (
>
> + IN UINT32 PageRequested,
>
> + OUT UINT32 *TotalSize,
>
> + OUT UINT32 *PageSize,
>
> + OUT BOOLEAN *HasMore,
>
> + OUT UINT8 **Buffer
>
> + )
>
> +{
>
> + EFI_STATUS Status;
>
> + EFI_MM_COMMUNICATE_HEADER *CommHeader;
>
> + VAR_CHECK_POLICY_COMM_HEADER *PolicyHeader;
>
> + VAR_CHECK_POLICY_COMM_DUMP_PARAMS *CommandParams;
>
> + UINTN BufferSize;
>
> +
>
> + if (TotalSize == NULL || PageSize == NULL || HasMore == NULL || Buffer
> == NULL) {
>
> + return EFI_INVALID_PARAMETER;
>
> + }
>
> +
>
> + // Set up the MM communication.
>
> + BufferSize = mMmCommunicationBufferSize;
>
> + CommHeader = mMmCommunicationBuffer;
>
> + PolicyHeader = (VAR_CHECK_POLICY_COMM_HEADER*)&CommHeader-
> >Data;
>
> + CommandParams =
> (VAR_CHECK_POLICY_COMM_DUMP_PARAMS*)(PolicyHeader + 1);
>
> + CopyGuid( &CommHeader->HeaderGuid,
> &gVarCheckPolicyLibMmiHandlerGuid );
>
> + CommHeader->MessageLength = BufferSize;
>
> + PolicyHeader->Signature = VAR_CHECK_POLICY_COMM_SIG;
>
> + PolicyHeader->Revision = VAR_CHECK_POLICY_COMM_REVISION;
>
> + PolicyHeader->Command = VAR_CHECK_POLICY_COMMAND_DUMP;
>
> +
>
> + CommandParams->PageRequested = PageRequested;
>
> +
>
> + Status = InternalMmCommunicate (CommHeader, &BufferSize);
>
> + DEBUG(( DEBUG_VERBOSE, "%a - MmCommunication returned %r.\n",
> __FUNCTION__, Status ));
>
> +
>
> + if (!EFI_ERROR( Status )) {
>
> + Status = PolicyHeader->Result;
>
> + *TotalSize = CommandParams->TotalSize;
>
> + *PageSize = CommandParams->PageSize;
>
> + *HasMore = CommandParams->HasMore;
>
> + *Buffer = (UINT8*)(CommandParams + 1);
>
> + }
>
> +
>
> + return Status;
>
> +}
>
> +
>
> +
>
> +/**
>
> + This API function will dump the entire contents of the variable policy table.
>
> +
>
> + Similar to GetVariable, the first call can be made with a 0 size and it will
> return
>
> + the size of the buffer required to hold the entire table.
>
> +
>
> + @param[out] Policy Pointer to the policy buffer. Can be NULL if Size is 0.
>
> + @param[in,out] Size On input, the size of the output buffer. On output,
> the size
>
> + of the data returned.
>
> +
>
> + @retval EFI_SUCCESS Policy data is in the output buffer and Size
> has been updated.
>
> + @retval EFI_INVALID_PARAMETER Size is NULL, or Size is non-zero and
> Policy is NULL.
>
> + @retval EFI_BUFFER_TOO_SMALL Size is insufficient to hold policy. Size
> updated with required size.
>
> +
>
> +**/
>
> +STATIC
>
> +EFI_STATUS
>
> +EFIAPI
>
> +ProtocolDumpVariablePolicy (
>
> + OUT UINT8 *Policy OPTIONAL,
>
> + IN OUT UINT32 *Size
>
> + )
>
> +{
>
> + EFI_STATUS Status;
>
> + UINT8 *Source;
>
> + UINT8 *Destination;
>
> + UINT32 PolicySize;
>
> + UINT32 PageSize;
>
> + BOOLEAN HasMore;
>
> + UINT32 PageIndex;
>
> +
>
> + if (Size == NULL || (*Size > 0 && Policy == NULL)) {
>
> + return EFI_INVALID_PARAMETER;
>
> + }
>
> +
>
> + AcquireLockOnlyAtBootTime (&mMmCommunicationLock);
>
> +
>
> + // Repeat this whole process until we either have a failure case or get the
> entire buffer.
>
> + do {
>
> + // First, we must check the zero page to determine the buffer size and
>
> + // reset the internal state.
>
> + PolicySize = 0;
>
> + PageSize = 0;
>
> + HasMore = FALSE;
>
> + Status = DumpVariablePolicyHelper (0, &PolicySize, &PageSize, &HasMore,
> &Source);
>
> + if (EFI_ERROR (Status)) {
>
> + break;
>
> + }
>
> +
>
> + // If we're good, we can at least check the required size now.
>
> + if (*Size < PolicySize) {
>
> + *Size = PolicySize;
>
> + Status = EFI_BUFFER_TOO_SMALL;
>
> + break;
>
> + }
>
> +
>
> + // On further thought, let's update the size either way.
>
> + *Size = PolicySize;
>
> + // And get ready to ROCK.
>
> + Destination = Policy;
>
> +
>
> + // Keep looping and copying until we're either done or freak out.
>
> + for (PageIndex = 1; !EFI_ERROR (Status) && HasMore && PageIndex <
> MAX_UINT32; PageIndex++) {
>
> + Status = DumpVariablePolicyHelper (PageIndex, &PolicySize, &PageSize,
> &HasMore, &Source);
>
> + if (!EFI_ERROR (Status)) {
>
> + CopyMem (Destination, Source, PageSize);
>
> + Destination += PageSize;
>
> + }
>
> + }
>
> +
>
> + // Next, we check to see whether
>
> + } while (Status == EFI_TIMEOUT);
>
> +
>
> + ReleaseLockOnlyAtBootTime (&mMmCommunicationLock);
>
> +
>
> + // There's currently no use for this, but it shouldn't be hard to implement.
>
> + return Status;
>
> +}
>
> +
>
> +
>
> +/**
>
> + This API function locks the interface so that no more policy updates
>
> + can be performed or changes made to the enforcement until the next
> boot.
>
> +
>
> + @retval EFI_SUCCESS
>
> + @retval Others An error has prevented this command from
> completing.
>
> +
>
> +**/
>
> +STATIC
>
> +EFI_STATUS
>
> +EFIAPI
>
> +ProtocolLockVariablePolicy (
>
> + VOID
>
> + )
>
> +{
>
> + EFI_STATUS Status;
>
> + EFI_MM_COMMUNICATE_HEADER *CommHeader;
>
> + VAR_CHECK_POLICY_COMM_HEADER *PolicyHeader;
>
> + UINTN BufferSize;
>
> +
>
> + AcquireLockOnlyAtBootTime (&mMmCommunicationLock);
>
> +
>
> + // Set up the MM communication.
>
> + BufferSize = mMmCommunicationBufferSize;
>
> + CommHeader = mMmCommunicationBuffer;
>
> + PolicyHeader = (VAR_CHECK_POLICY_COMM_HEADER*)&CommHeader-
> >Data;
>
> + CopyGuid( &CommHeader->HeaderGuid,
> &gVarCheckPolicyLibMmiHandlerGuid );
>
> + CommHeader->MessageLength = BufferSize;
>
> + PolicyHeader->Signature = VAR_CHECK_POLICY_COMM_SIG;
>
> + PolicyHeader->Revision = VAR_CHECK_POLICY_COMM_REVISION;
>
> + PolicyHeader->Command = VAR_CHECK_POLICY_COMMAND_LOCK;
>
> +
>
> + Status = InternalMmCommunicate (CommHeader, &BufferSize);
>
> + DEBUG(( DEBUG_VERBOSE, "%a - MmCommunication returned %r.\n",
> __FUNCTION__, Status ));
>
> +
>
> + ReleaseLockOnlyAtBootTime (&mMmCommunicationLock);
>
> +
>
> + return (EFI_ERROR( Status )) ? Status : PolicyHeader->Result;
>
> +}
>
> +
>
> +
>
> +/**
>
> + This helper function locates the shared comm buffer and assigns it to input
> pointers.
>
> +
>
> + @param[in,out] BufferSize On input, the minimum buffer size required
> INCLUDING the MM communicate header.
>
> + On output, the size of the matching buffer found.
>
> + @param[out] LocatedBuffer A pointer to the matching buffer.
>
> +
>
> + @retval EFI_SUCCESS
>
> + @retval EFI_INVALID_PARAMETER One of the output pointers was
> NULL.
>
> + @retval EFI_OUT_OF_RESOURCES Not enough memory to allocate a
> comm buffer.
>
> +
>
> +**/
>
> +STATIC
>
> +EFI_STATUS
>
> +InitMmCommonCommBuffer (
>
> + IN OUT UINTN *BufferSize,
>
> + OUT VOID **LocatedBuffer
>
> + )
>
> +{
>
> + EFI_STATUS Status;
>
> +
>
> + Status = EFI_SUCCESS;
>
> +
>
> + // Make sure that we're working with good pointers.
>
> + if (BufferSize == NULL || LocatedBuffer == NULL) {
>
> + return EFI_INVALID_PARAMETER;
>
> + }
>
> +
>
> + // Allocate the runtime memory for the comm buffer.
>
> + *LocatedBuffer = AllocateRuntimePool (*BufferSize);
>
> + if (*LocatedBuffer == NULL) {
>
> + Status = EFI_OUT_OF_RESOURCES;
>
> + *BufferSize = 0;
>
> + }
>
> +
>
> + EfiInitializeLock (&mMmCommunicationLock, TPL_NOTIFY);
>
> +
>
> + return Status;
>
> +}
>
> +
>
> +
>
> +/**
>
> + This helper is responsible for telemetry and any other actions that
>
> + need to be taken if the VariablePolicy fails to lock.
>
> +
>
> + NOTE: It's possible that parts of this handling will need to become
>
> + part of a platform policy.
>
> +
>
> + @param[in] FailureStatus The failure that was reported by
> LockVariablePolicy
>
> +
>
> +**/
>
> +STATIC
>
> +VOID
>
> +VariablePolicyHandleFailureToLock (
>
> + IN EFI_STATUS FailureStatus
>
> + )
>
> +{
>
> + // For now, there's no agreed-upon policy for this.
>
> + return;
>
> +}
>
> +
>
> +
>
> +/**
>
> + ReadyToBoot Callback
>
> + Lock the VariablePolicy interface if it hasn't already been locked.
>
> +
>
> + @param[in] Event Event whose notification function is being invoked
>
> + @param[in] Context Pointer to the notification function's context
>
> +
>
> +**/
>
> +STATIC
>
> +VOID
>
> +EFIAPI
>
> +LockPolicyInterfaceAtReadyToBoot (
>
> + IN EFI_EVENT Event,
>
> + IN VOID *Context
>
> + )
>
> +{
>
> + EFI_STATUS Status;
>
> +
>
> + Status = ProtocolLockVariablePolicy();
>
> +
>
> + if (EFI_ERROR( Status )) {
>
> + VariablePolicyHandleFailureToLock( Status );
>
> + }
>
> + else {
>
> + gBS->CloseEvent( Event );
>
> + }
>
> +
>
> +}
>
> +
>
> +
>
> +/**
>
> + Convert internal pointer addresses to virtual addresses.
>
> +
>
> + @param[in] Event Event whose notification function is being invoked.
>
> + @param[in] Context The pointer to the notification function's context,
> which
>
> + is implementation-dependent.
>
> +**/
>
> +STATIC
>
> +VOID
>
> +EFIAPI
>
> +VariablePolicyVirtualAddressCallback (
>
> + IN EFI_EVENT Event,
>
> + IN VOID *Context
>
> + )
>
> +{
>
> + EfiConvertPointer (0, (VOID **)&mMmCommunication);
>
> + EfiConvertPointer (0, (VOID **)&mMmCommunicationBuffer);
>
> +}
>
> +
>
> +
>
> +/**
>
> + The driver's entry point.
>
> +
>
> + @param[in] ImageHandle The firmware allocated handle for the EFI image.
>
> + @param[in] SystemTable A pointer to the EFI System Table.
>
> +
>
> + @retval EFI_SUCCESS The entry point executed successfully.
>
> + @retval other Some error occured when executing this entry point.
>
> +
>
> +**/
>
> +EFI_STATUS
>
> +EFIAPI
>
> +VariablePolicySmmDxeMain (
>
> + IN EFI_HANDLE ImageHandle,
>
> + IN EFI_SYSTEM_TABLE *SystemTable
>
> + )
>
> +{
>
> + EFI_STATUS Status;
>
> + BOOLEAN ProtocolInstalled;
>
> + BOOLEAN CallbackRegistered;
>
> + BOOLEAN VirtualAddressChangeRegistered;
>
> + EFI_EVENT ReadyToBootEvent;
>
> + EFI_EVENT VirtualAddressChangeEvent;
>
> +
>
> + Status = EFI_SUCCESS;
>
> + ProtocolInstalled = FALSE;
>
> + CallbackRegistered = FALSE;
>
> + VirtualAddressChangeRegistered = FALSE;
>
> +
>
> + // Update the minimum buffer size.
>
> + mMmCommunicationBufferSize =
> VAR_CHECK_POLICY_MM_COMM_BUFFER_SIZE;
>
> + // Locate the shared comm buffer to use for sending MM commands.
>
> + Status = InitMmCommonCommBuffer( &mMmCommunicationBufferSize,
> &mMmCommunicationBuffer );
>
> + if (EFI_ERROR( Status )) {
>
> + DEBUG((DEBUG_ERROR, "%a - Failed to locate a viable MM comm
> buffer! %r\n", __FUNCTION__, Status));
>
> + ASSERT_EFI_ERROR( Status );
>
> + return Status;
>
> + }
>
> +
>
> + // Locate the MmCommunication protocol.
>
> + Status = gBS->LocateProtocol( &gEfiMmCommunication2ProtocolGuid,
> NULL, (VOID**)&mMmCommunication );
>
> + if (EFI_ERROR( Status )) {
>
> + DEBUG((DEBUG_ERROR, "%a - Failed to locate MmCommunication
> protocol! %r\n", __FUNCTION__, Status));
>
> + ASSERT_EFI_ERROR( Status );
>
> + return Status;
>
> + }
>
> +
>
> + // Configure the VariablePolicy protocol structure.
>
> + mVariablePolicyProtocol.Revision =
> EDKII_VARIABLE_POLICY_PROTOCOL_REVISION;
>
> + mVariablePolicyProtocol.DisableVariablePolicy =
> ProtocolDisableVariablePolicy;
>
> + mVariablePolicyProtocol.IsVariablePolicyEnabled =
> ProtocolIsVariablePolicyEnabled;
>
> + mVariablePolicyProtocol.RegisterVariablePolicy =
> ProtocolRegisterVariablePolicy;
>
> + mVariablePolicyProtocol.DumpVariablePolicy =
> ProtocolDumpVariablePolicy;
>
> + mVariablePolicyProtocol.LockVariablePolicy = ProtocolLockVariablePolicy;
>
> +
>
> + // Register all the protocols and return the status.
>
> + Status = gBS->InstallMultipleProtocolInterfaces( &ImageHandle,
>
> + &gEdkiiVariablePolicyProtocolGuid,
> &mVariablePolicyProtocol,
>
> + NULL );
>
> + if (EFI_ERROR( Status )) {
>
> + DEBUG(( DEBUG_ERROR, "%a - Failed to install protocol! %r\n",
> __FUNCTION__, Status ));
>
> + goto Exit;
>
> + }
>
> + else {
>
> + ProtocolInstalled = TRUE;
>
> + }
>
> +
>
> + //
>
> + // Register a callback for ReadyToBoot so that the interface is at least
> locked before
>
> + // dispatching any bootloaders or UEFI apps.
>
> + Status = gBS->CreateEventEx( EVT_NOTIFY_SIGNAL,
>
> + TPL_CALLBACK,
>
> + LockPolicyInterfaceAtReadyToBoot,
>
> + NULL,
>
> + &gEfiEventReadyToBootGuid,
>
> + &ReadyToBootEvent );
>
> + if (EFI_ERROR( Status )) {
>
> + DEBUG(( DEBUG_ERROR, "%a - Failed to create ReadyToBoot
> event! %r\n", __FUNCTION__, Status ));
>
> + goto Exit;
>
> + }
>
> + else {
>
> + CallbackRegistered = TRUE;
>
> + }
>
> +
>
> + //
>
> + // Register a VirtualAddressChange callback for the MmComm protocol
> and Comm buffer.
>
> + Status = gBS->CreateEventEx (EVT_NOTIFY_SIGNAL,
>
> + TPL_NOTIFY,
>
> + VariablePolicyVirtualAddressCallback,
>
> + NULL,
>
> + &gEfiEventVirtualAddressChangeGuid,
>
> + &VirtualAddressChangeEvent);
>
> + if (EFI_ERROR( Status )) {
>
> + DEBUG(( DEBUG_ERROR, "%a - Failed to create VirtualAddressChange
> event! %r\n", __FUNCTION__, Status ));
>
> + goto Exit;
>
> + }
>
> + else {
>
> + VirtualAddressChangeRegistered = TRUE;
>
> + }
>
> +
>
> +
>
> +Exit:
>
> + //
>
> + // If we're about to return a failed status (and unload this driver), we must
> first undo anything that
>
> + // has been successfully done.
>
> + if (EFI_ERROR( Status )) {
>
> + if (ProtocolInstalled) {
>
> + gBS->UninstallProtocolInterface( &ImageHandle,
> &gEdkiiVariablePolicyProtocolGuid, &mVariablePolicyProtocol );
>
> + }
>
> + if (CallbackRegistered) {
>
> + gBS->CloseEvent( ReadyToBootEvent );
>
> + }
>
> + if (VirtualAddressChangeRegistered) {
>
> + gBS->CloseEvent( VirtualAddressChangeEvent );
>
> + }
>
> + }
>
> +
>
> + return Status;
>
> +}
>
> diff --git
> a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> e.c
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> e.c
> index 663a1aaa128f..c47e614d81f4 100644
> ---
> a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> e.c
> +++
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> e.c
> @@ -65,6 +65,17 @@ EFI_LOCK mVariableServicesLock;
> EDKII_VARIABLE_LOCK_PROTOCOL mVariableLock;
>
> EDKII_VAR_CHECK_PROTOCOL mVarCheck;
>
>
>
> +/**
>
> + The logic to initialize the VariablePolicy engine is in its own file.
>
> +
>
> +**/
>
> +EFI_STATUS
>
> +EFIAPI
>
> +VariablePolicySmmDxeMain (
>
> + IN EFI_HANDLE ImageHandle,
>
> + IN EFI_SYSTEM_TABLE *SystemTable
>
> + );
>
> +
>
> /**
>
> Some Secure Boot Policy Variable may update following other variable
> changes(SecureBoot follows PK change, etc).
>
> Record their initial State when variable write service is ready.
>
> @@ -1796,6 +1807,9 @@ VariableSmmRuntimeInitialize (
> &mVirtualAddressChangeEvent
>
> );
>
>
>
> + // Initialize the VariablePolicy protocol and engine.
>
> + VariablePolicySmmDxeMain (ImageHandle, SystemTable);
>
> +
>
> return EFI_SUCCESS;
>
> }
>
>
>
> diff --git
> a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> index ceea5d1ff9ac..48ac167906f7 100644
> ---
> a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> +++
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableRuntimeDxe.inf
> @@ -10,6 +10,7 @@
> # buffer overflow or integer overflow.
>
> #
>
> # Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
>
> +# Copyright (c) Microsoft Corporation.
>
> # SPDX-License-Identifier: BSD-2-Clause-Patent
>
> #
>
> ##
>
> @@ -69,6 +70,7 @@ [LibraryClasses]
> TpmMeasurementLib
>
> AuthVariableLib
>
> VarCheckLib
>
> + VariablePolicyLib
>
>
>
> [Protocols]
>
> gEfiFirmwareVolumeBlockProtocolGuid ## CONSUMES
>
> diff --git
> a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> index bc3033588d40..bbc8d2080193 100644
> --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
> @@ -19,6 +19,7 @@
> # the authentication service provided in this driver will be broken, and the
> behavior is undefined.
>
> #
>
> # Copyright (c) 2010 - 2019, Intel Corporation. All rights reserved.<BR>
>
> +# Copyright (c) Microsoft Corporation.
>
> # SPDX-License-Identifier: BSD-2-Clause-Patent
>
> #
>
> ##
>
> @@ -78,6 +79,8 @@ [LibraryClasses]
> AuthVariableLib
>
> VarCheckLib
>
> UefiBootServicesTableLib
>
> + VariablePolicyLib
>
> + VariablePolicyHelperLib
>
>
>
> [Protocols]
>
> gEfiSmmFirmwareVolumeBlockProtocolGuid ## CONSUMES
>
> diff --git
> a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> e.inf
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> e.inf
> index 01564e4c5068..f217530b2985 100644
> ---
> a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> e.inf
> +++
> b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDx
> e.inf
> @@ -14,6 +14,7 @@
> # the authentication service provided in this driver will be broken, and the
> behavior is undefined.
>
> #
>
> # Copyright (c) 2010 - 2019, Intel Corporation. All rights reserved.<BR>
>
> +# Copyright (c) Microsoft Corporation.<BR>
>
> # SPDX-License-Identifier: BSD-2-Clause-Patent
>
> #
>
> ##
>
> @@ -42,6 +43,7 @@ [Sources]
> VariableParsing.c
>
> VariableParsing.h
>
> Variable.h
>
> + VariablePolicySmmDxe.c
>
>
>
> [Packages]
>
> MdePkg/MdePkg.dec
>
> @@ -56,6 +58,8 @@ [LibraryClasses]
> DxeServicesTableLib
>
> UefiDriverEntryPoint
>
> TpmMeasurementLib
>
> + SafeIntLib
>
> + PcdLib
>
>
>
> [Protocols]
>
> gEfiVariableWriteArchProtocolGuid ## PRODUCES
>
> @@ -67,11 +71,15 @@ [Protocols]
> gEfiSmmVariableProtocolGuid
>
> gEdkiiVariableLockProtocolGuid ## PRODUCES
>
> gEdkiiVarCheckProtocolGuid ## PRODUCES
>
> + gEdkiiVariablePolicyProtocolGuid ## PRODUCES
>
>
>
> [FeaturePcd]
>
> gEfiMdeModulePkgTokenSpaceGuid.PcdEnableVariableRuntimeCache
> ## CONSUMES
>
> gEfiMdeModulePkgTokenSpaceGuid.PcdVariableCollectStatistics ##
> CONSUMES
>
>
>
> +[Pcd]
>
> +
> gEfiMdeModulePkgTokenSpaceGuid.PcdAllowVariablePolicyEnforcementDis
> able ## CONSUMES
>
> +
>
> [Guids]
>
> ## PRODUCES ## GUID # Signature of Variable store header
>
> ## CONSUMES ## GUID # Signature of Variable store header
>
> @@ -99,6 +107,8 @@ [Guids]
> ## SOMETIMES_CONSUMES ## Variable:L"dbt"
>
> gEfiImageSecurityDatabaseGuid
>
>
>
> + gVarCheckPolicyLibMmiHandlerGuid
>
> +
>
> [Depex]
>
> gEfiMmCommunication2ProtocolGuid
>
>
>
> --
> 2.26.2.windows.1.8.g01c50adf56.20200515075929
>
>
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