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/** @file
TCG MOR (Memory Overwrite Request) Lock Control Driver.
This driver initilize MemoryOverwriteRequestControlLock variable.
This module will add Variable Hook and allow MemoryOverwriteRequestControlLock variable set only once.
Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include <PiDxe.h>
#include <Guid/MemoryOverwriteControl.h>
#include <IndustryStandard/MemoryOverwriteRequestControlLock.h>
#include <Library/DebugLib.h>
#include <Library/BaseLib.h>
#include <Library/BaseMemoryLib.h>
#include "TcgMorLock.h"
typedef struct {
CHAR16 *VariableName;
EFI_GUID *VendorGuid;
} VARIABLE_TYPE;
VARIABLE_TYPE mMorVariableType[] = {
{MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME, &gEfiMemoryOverwriteControlDataGuid},
{MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME, &gEfiMemoryOverwriteRequestControlLockGuid},
};
/**
Returns if this is MOR related variable.
@param VariableName the name of the vendor's variable, it's a Null-Terminated Unicode String
@param VendorGuid Unify identifier for vendor.
@retval TRUE The variable is MOR related.
@retval FALSE The variable is NOT MOR related.
**/
BOOLEAN
IsAnyMorVariable (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid
)
{
UINTN Index;
for (Index = 0; Index < sizeof(mMorVariableType)/sizeof(mMorVariableType[0]); Index++) {
if ((StrCmp (VariableName, mMorVariableType[Index].VariableName) == 0) &&
(CompareGuid (VendorGuid, mMorVariableType[Index].VendorGuid))) {
return TRUE;
}
}
return FALSE;
}
/**
Returns if this is MOR lock variable.
@param VariableName the name of the vendor's variable, it's a Null-Terminated Unicode String
@param VendorGuid Unify identifier for vendor.
@retval TRUE The variable is MOR lock variable.
@retval FALSE The variable is NOT MOR lock variable.
**/
BOOLEAN
IsMorLockVariable (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid
)
{
if ((StrCmp (VariableName, MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME) == 0) &&
(CompareGuid (VendorGuid, &gEfiMemoryOverwriteRequestControlLockGuid))) {
return TRUE;
}
return FALSE;
}
/**
This service is a checker handler for the UEFI Runtime Service SetVariable()
@param VariableName the name of the vendor's variable, as a
Null-Terminated Unicode String
@param VendorGuid Unify identifier for vendor.
@param Attributes Point to memory location to return the attributes of variable. If the point
is NULL, the parameter would be ignored.
@param DataSize The size in bytes of Data-Buffer.
@param Data Point to the content of the variable.
@retval EFI_SUCCESS The firmware has successfully stored the variable and its data as
defined by the Attributes.
@retval EFI_INVALID_PARAMETER An invalid combination of attribute bits was supplied, or the
DataSize exceeds the maximum allowed.
@retval EFI_INVALID_PARAMETER VariableName is an empty Unicode string.
@retval EFI_OUT_OF_RESOURCES Not enough storage is available to hold the variable and its data.
@retval EFI_DEVICE_ERROR The variable could not be saved due to a hardware failure.
@retval EFI_WRITE_PROTECTED The variable in question is read-only.
@retval EFI_WRITE_PROTECTED The variable in question cannot be deleted.
@retval EFI_SECURITY_VIOLATION The variable could not be written due to EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
set but the AuthInfo does NOT pass the validation check carried
out by the firmware.
@retval EFI_NOT_FOUND The variable trying to be updated or deleted was not found.
**/
EFI_STATUS
EFIAPI
SetVariableCheckHandlerMor (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN UINT32 Attributes,
IN UINTN DataSize,
IN VOID *Data
)
{
UINTN MorLockDataSize;
BOOLEAN MorLock;
EFI_STATUS Status;
//
// do not handle non-MOR variable
//
if (!IsAnyMorVariable (VariableName, VendorGuid)) {
return EFI_SUCCESS;
}
MorLockDataSize = sizeof(MorLock);
Status = InternalGetVariable (
MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,
&gEfiMemoryOverwriteRequestControlLockGuid,
NULL,
&MorLockDataSize,
&MorLock
);
if (!EFI_ERROR (Status) && MorLock) {
//
// If lock, deny access
//
return EFI_INVALID_PARAMETER;
}
//
// Delete not OK
//
if ((DataSize != sizeof(UINT8)) || (Data == NULL) || (Attributes == 0)) {
return EFI_INVALID_PARAMETER;
}
//
// check format
//
if (IsMorLockVariable(VariableName, VendorGuid)) {
//
// set to any other value not OK
//
if ((*(UINT8 *)Data != 1) && (*(UINT8 *)Data != 0)) {
return EFI_INVALID_PARAMETER;
}
}
//
// Or grant access
//
return EFI_SUCCESS;
}
/**
Entry Point for MOR Lock Control driver.
@param[in] ImageHandle Image handle of this driver.
@param[in] SystemTable A Pointer to the EFI System Table.
@retval EFI_SUCEESS
@return Others Some error occurs.
**/
EFI_STATUS
EFIAPI
MorLockDriverInit (
VOID
)
{
EFI_STATUS Status;
UINT8 Data;
Data = 0;
Status = InternalSetVariable (
MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,
&gEfiMemoryOverwriteRequestControlLockGuid,
EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
1,
&Data
);
return Status;
}
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