1 /** @file 2 TCG MOR (Memory Overwrite Request) Lock Control support (DXE version). 3 4 This module clears MemoryOverwriteRequestControlLock variable to indicate 5 MOR lock control unsupported. 6 7 Copyright (c) 2016, Intel Corporation. All rights reserved.<BR> 8 This program and the accompanying materials 9 are licensed and made available under the terms and conditions of the BSD License 10 which accompanies this distribution. The full text of the license may be found at 11 http://opensource.org/licenses/bsd-license.php 12 13 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 14 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 15 16 **/ 17 18 #include <PiDxe.h> 19 #include <Guid/MemoryOverwriteControl.h> 20 #include <IndustryStandard/MemoryOverwriteRequestControlLock.h> 21 #include <Library/DebugLib.h> 22 #include <Library/BaseLib.h> 23 #include <Library/BaseMemoryLib.h> 24 #include "Variable.h" 25 26 extern EDKII_VARIABLE_LOCK_PROTOCOL mVariableLock; 27 28 /** 29 This service is an MOR/MorLock checker handler for the SetVariable(). 30 31 @param VariableName the name of the vendor's variable, as a 32 Null-Terminated Unicode String 33 @param VendorGuid Unify identifier for vendor. 34 @param Attributes Point to memory location to return the attributes of variable. If the point 35 is NULL, the parameter would be ignored. 36 @param DataSize The size in bytes of Data-Buffer. 37 @param Data Point to the content of the variable. 38 39 @retval EFI_SUCCESS The MOR/MorLock check pass, and Variable driver can store the variable data. 40 @retval EFI_INVALID_PARAMETER The MOR/MorLock data or data size or attributes is not allowed for MOR variable. 41 @retval EFI_ACCESS_DENIED The MOR/MorLock is locked. 42 @retval EFI_ALREADY_STARTED The MorLock variable is handled inside this function. 43 Variable driver can just return EFI_SUCCESS. 44 **/ 45 EFI_STATUS 46 SetVariableCheckHandlerMor ( 47 IN CHAR16 *VariableName, 48 IN EFI_GUID *VendorGuid, 49 IN UINT32 Attributes, 50 IN UINTN DataSize, 51 IN VOID *Data 52 ) 53 { 54 // 55 // Just let it pass. No need provide protection for DXE version. 56 // 57 return EFI_SUCCESS; 58 } 59 60 /** 61 Initialization for MOR Lock Control. 62 63 @retval EFI_SUCEESS MorLock initialization success. 64 @return Others Some error occurs. 65 **/ 66 EFI_STATUS 67 MorLockInit ( 68 VOID 69 ) 70 { 71 // 72 // Always clear variable to report unsupported to OS. 73 // The reason is that the DXE version is not proper to provide *protection*. 74 // BIOS should use SMM version variable driver to provide such capability. 75 // 76 VariableServiceSetVariable ( 77 MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME, 78 &gEfiMemoryOverwriteRequestControlLockGuid, 79 EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS, 80 0, 81 NULL 82 ); 83 84 // 85 // Need set this variable to be read-only to prevent other module set it. 86 // 87 VariableLockRequestToLock (&mVariableLock, MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME, &gEfiMemoryOverwriteRequestControlLockGuid); 88 return EFI_SUCCESS; 89 } 90
