SecurityPkg/Tcg/MemoryOverwriteRequestControlLock/TcgMorLock.c

   1 /** @file
   2   TCG MOR (Memory Overwrite Request) Lock Control Driver.
   3
   4   This driver initilize MemoryOverwriteRequestControlLock variable.
   5   This module will add Variable Hook and allow MemoryOverwriteRequestControlLock variable set only once.
   6
   7 Copyright (c) 2015 - 2018, 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 "TcgMorLock.h"
  25
  26 typedef struct {
  27   CHAR16                                 *VariableName;
  28   EFI_GUID                               *VendorGuid;
  29 } VARIABLE_TYPE;
  30
  31 VARIABLE_TYPE  mMorVariableType[] = {
  32   {MEMORY_OVERWRITE_REQUEST_VARIABLE_NAME,      &gEfiMemoryOverwriteControlDataGuid},
  33   {MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,  &gEfiMemoryOverwriteRequestControlLockGuid},
  34 };
  35
  36 /**
  37   Returns if this is MOR related variable.
  38
  39   @param  VariableName the name of the vendor's variable, it's a Null-Terminated Unicode String
  40   @param  VendorGuid   Unify identifier for vendor.
  41
  42   @retval  TRUE            The variable is MOR related.
  43   @retval  FALSE           The variable is NOT MOR related.
  44 **/
  45 BOOLEAN
  46 IsAnyMorVariable (
  47   IN CHAR16                                 *VariableName,
  48   IN EFI_GUID                               *VendorGuid
  49   )
  50 {
  51   UINTN   Index;
  52
  53   for (Index = 0; Index < sizeof(mMorVariableType)/sizeof(mMorVariableType[0]); Index++) {
  54     if ((StrCmp (VariableName, mMorVariableType[Index].VariableName) == 0) &&
  55         (CompareGuid (VendorGuid, mMorVariableType[Index].VendorGuid))) {
  56       return TRUE;
  57     }
  58   }
  59   return FALSE;
  60 }
  61
  62 /**
  63   Returns if this is MOR lock variable.
  64
  65   @param  VariableName the name of the vendor's variable, it's a Null-Terminated Unicode String
  66   @param  VendorGuid   Unify identifier for vendor.
  67
  68   @retval  TRUE            The variable is MOR lock variable.
  69   @retval  FALSE           The variable is NOT MOR lock variable.
  70 **/
  71 BOOLEAN
  72 IsMorLockVariable (
  73   IN CHAR16                                 *VariableName,
  74   IN EFI_GUID                               *VendorGuid
  75   )
  76 {
  77   if ((StrCmp (VariableName, MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME) == 0) &&
  78       (CompareGuid (VendorGuid, &gEfiMemoryOverwriteRequestControlLockGuid))) {
  79     return TRUE;
  80   }
  81   return FALSE;
  82 }
  83
  84 /**
  85   This service is a checker handler for the UEFI Runtime Service SetVariable()
  86
  87   @param  VariableName the name of the vendor's variable, as a
  88                        Null-Terminated Unicode String
  89   @param  VendorGuid   Unify identifier for vendor.
  90   @param  Attributes   Point to memory location to return the attributes of variable. If the point
  91                        is NULL, the parameter would be ignored.
  92   @param  DataSize     The size in bytes of Data-Buffer.
  93   @param  Data         Point to the content of the variable.
  94
  95   @retval  EFI_SUCCESS            The firmware has successfully stored the variable and its data as
  96                                   defined by the Attributes.
  97   @retval  EFI_INVALID_PARAMETER  An invalid combination of attribute bits was supplied, or the
  98                                   DataSize exceeds the maximum allowed.
  99   @retval  EFI_INVALID_PARAMETER  VariableName is an empty Unicode string.
 100   @retval  EFI_OUT_OF_RESOURCES   Not enough storage is available to hold the variable and its data.
 101   @retval  EFI_DEVICE_ERROR       The variable could not be saved due to a hardware failure.
 102   @retval  EFI_WRITE_PROTECTED    The variable in question is read-only.
 103   @retval  EFI_WRITE_PROTECTED    The variable in question cannot be deleted.
 104   @retval  EFI_SECURITY_VIOLATION The variable could not be written due to EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
 105                                   set but the AuthInfo does NOT pass the validation check carried
 106                                   out by the firmware.
 107   @retval  EFI_NOT_FOUND          The variable trying to be updated or deleted was not found.
 108
 109 **/
 110 EFI_STATUS
 111 EFIAPI
 112 SetVariableCheckHandlerMor (
 113   IN CHAR16     *VariableName,
 114   IN EFI_GUID   *VendorGuid,
 115   IN UINT32     Attributes,
 116   IN UINTN      DataSize,
 117   IN VOID       *Data
 118   )
 119 {
 120   UINTN       MorLockDataSize;
 121   BOOLEAN     MorLock;
 122   EFI_STATUS  Status;
 123
 124   //
 125   // do not handle non-MOR variable
 126   //
 127   if (!IsAnyMorVariable (VariableName, VendorGuid)) {
 128     return EFI_SUCCESS;
 129   }
 130
 131   MorLockDataSize = sizeof(MorLock);
 132   Status = InternalGetVariable (
 133              MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,
 134              &gEfiMemoryOverwriteRequestControlLockGuid,
 135              NULL,
 136              &MorLockDataSize,
 137              &MorLock
 138              );
 139   if (!EFI_ERROR (Status) && MorLock) {
 140     //
 141     // If lock, deny access
 142     //
 143     return EFI_INVALID_PARAMETER;
 144   }
 145
 146   //
 147   // Delete not OK
 148   //
 149   if ((DataSize != sizeof(UINT8)) || (Data == NULL) || (Attributes == 0)) {
 150     return EFI_INVALID_PARAMETER;
 151   }
 152
 153   //
 154   // check format
 155   //
 156   if (IsMorLockVariable(VariableName, VendorGuid)) {
 157     //
 158     // set to any other value not OK
 159     //
 160     if ((*(UINT8 *)Data != 1) && (*(UINT8 *)Data != 0)) {
 161       return EFI_INVALID_PARAMETER;
 162     }
 163   }
 164   //
 165   // Or grant access
 166   //
 167   return EFI_SUCCESS;
 168 }
 169
 170 /**
 171   Entry Point for MOR Lock Control driver.
 172
 173   @param[in] ImageHandle  Image handle of this driver.
 174   @param[in] SystemTable  A Pointer to the EFI System Table.
 175
 176   @retval EFI_SUCEESS
 177   @return Others          Some error occurs.
 178 **/
 179 EFI_STATUS
 180 EFIAPI
 181 MorLockDriverInit (
 182   VOID
 183   )
 184 {
 185   EFI_STATUS  Status;
 186   UINT8       Data;
 187
 188   Data = 0;
 189   Status = InternalSetVariable (
 190              MEMORY_OVERWRITE_REQUEST_CONTROL_LOCK_NAME,
 191              &gEfiMemoryOverwriteRequestControlLockGuid,
 192              EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS,
 193              1,
 194              &Data
 195              );
 196   return Status;
 197 }