]> git.proxmox.com Git - mirror_edk2.git/blobdiff - SecurityPkg/VariableAuthenticated/RuntimeDxe/VariableSmm.c
Fix the return value bug when updating public key database variable failure.
[mirror_edk2.git] / SecurityPkg / VariableAuthenticated / RuntimeDxe / VariableSmm.c
index 197735e3992b27f2ad45a9cc36aa77b06686b4cb..63ac4361503ab1d9f6d583e2bcdf73c7898f37d9 100644 (file)
@@ -3,7 +3,18 @@
   implements an SMI handler to communicate with the DXE runtime driver \r
   to provide variable services.\r
 \r
-Copyright (c) 2010 - 2011, Intel Corporation. All rights reserved.<BR>\r
+  Caution: This module requires additional review when modified.\r
+  This driver will have external input - variable data and communicate buffer in SMM mode.\r
+  This external input must be validated carefully to avoid security issue like\r
+  buffer overflow, integer overflow.\r
+\r
+  SmmVariableHandler() will receive untrusted input and do basic validation.\r
+\r
+  Each sub function VariableServiceGetVariable(), VariableServiceGetNextVariableName(), \r
+  VariableServiceSetVariable(), VariableServiceQueryVariableInfo(), ReclaimForOS(), \r
+  SmmVariableGetStatistics() should also do validation based on its own knowledge.\r
+\r
+Copyright (c) 2010 - 2014, Intel Corporation. All rights reserved.<BR>\r
 This program and the accompanying materials \r
 are licensed and made available under the terms and conditions of the BSD License \r
 which accompanies this distribution.  The full text of the license may be found at \r
@@ -17,26 +28,97 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #include <Protocol/SmmVariable.h>\r
 #include <Protocol/SmmFirmwareVolumeBlock.h>\r
 #include <Protocol/SmmFaultTolerantWrite.h>\r
+#include <Protocol/SmmAccess2.h>\r
+#include <Protocol/SmmEndOfDxe.h>\r
+\r
 #include <Library/SmmServicesTableLib.h>\r
 \r
 #include <Guid/AuthenticatedVariableFormat.h>\r
 #include <Guid/SmmVariableCommon.h>\r
 #include "Variable.h"\r
 \r
+EFI_SMRAM_DESCRIPTOR                                 *mSmramRanges;\r
+UINTN                                                mSmramRangeCount;\r
+\r
 extern VARIABLE_INFO_ENTRY                           *gVariableInfo;\r
 EFI_HANDLE                                           mSmmVariableHandle      = NULL;\r
 EFI_HANDLE                                           mVariableHandle         = NULL;\r
 BOOLEAN                                              mAtRuntime              = FALSE;\r
 EFI_GUID                                             mZeroGuid               = {0, 0, 0, {0, 0, 0, 0, 0, 0, 0, 0}};\r
-  \r
+UINT8                                                *mVariableBufferPayload = NULL;\r
+UINTN                                                mVariableBufferPayloadSize;\r
+extern BOOLEAN                                       mEndOfDxe;\r
+extern BOOLEAN                                       mEnableLocking;\r
+\r
+/**\r
+  SecureBoot Hook for SetVariable.\r
+\r
+  @param[in] VariableName                 Name of Variable to be found.\r
+  @param[in] VendorGuid                   Variable vendor GUID.\r
+\r
+**/\r
+VOID\r
+EFIAPI\r
+SecureBootHook (\r
+  IN CHAR16                                 *VariableName,\r
+  IN EFI_GUID                               *VendorGuid\r
+  )\r
+{\r
+  return ;\r
+}\r
+\r
+/**\r
+\r
+  This code sets variable in storage blocks (Volatile or Non-Volatile).\r
+\r
+  @param VariableName                     Name of Variable to be found.\r
+  @param VendorGuid                       Variable vendor GUID.\r
+  @param Attributes                       Attribute value of the variable found\r
+  @param DataSize                         Size of Data found. If size is less than the\r
+                                          data, this value contains the required size.\r
+  @param Data                             Data pointer.\r
+\r
+  @return EFI_INVALID_PARAMETER           Invalid parameter.\r
+  @return EFI_SUCCESS                     Set successfully.\r
+  @return EFI_OUT_OF_RESOURCES            Resource not enough to set variable.\r
+  @return EFI_NOT_FOUND                   Not found.\r
+  @return EFI_WRITE_PROTECTED             Variable is read-only.\r
+\r
+**/\r
+EFI_STATUS\r
+EFIAPI\r
+SmmVariableSetVariable (\r
+  IN CHAR16                  *VariableName,\r
+  IN EFI_GUID                *VendorGuid,\r
+  IN UINT32                  Attributes,\r
+  IN UINTN                   DataSize,\r
+  IN VOID                    *Data\r
+  )\r
+{\r
+  EFI_STATUS                 Status;\r
+\r
+  //\r
+  // Disable write protection when the calling SetVariable() through EFI_SMM_VARIABLE_PROTOCOL.\r
+  //\r
+  mEnableLocking = FALSE;\r
+  Status         = VariableServiceSetVariable (\r
+                     VariableName,\r
+                     VendorGuid,\r
+                     Attributes,\r
+                     DataSize,\r
+                     Data\r
+                     );\r
+  mEnableLocking = TRUE;\r
+  return Status;\r
+}\r
+\r
 EFI_SMM_VARIABLE_PROTOCOL      gSmmVariable = {\r
   VariableServiceGetVariable,\r
   VariableServiceGetNextVariableName,\r
-  VariableServiceSetVariable,\r
+  SmmVariableSetVariable,\r
   VariableServiceQueryVariableInfo\r
 };\r
 \r
-\r
 /**\r
   Return TRUE if ExitBootServices () has been called.\r
   \r
@@ -50,6 +132,60 @@ AtRuntime (
   return mAtRuntime;\r
 }\r
 \r
+/**\r
+  This function check if the address is in SMRAM.\r
+\r
+  @param Buffer  the buffer address to be checked.\r
+  @param Length  the buffer length to be checked.\r
+\r
+  @retval TRUE  this address is in SMRAM.\r
+  @retval FALSE this address is NOT in SMRAM.\r
+**/\r
+BOOLEAN\r
+InternalIsAddressInSmram (\r
+  IN EFI_PHYSICAL_ADDRESS  Buffer,\r
+  IN UINT64                Length\r
+  )\r
+{\r
+  UINTN  Index;\r
+\r
+  for (Index = 0; Index < mSmramRangeCount; Index ++) {\r
+    if (((Buffer >= mSmramRanges[Index].CpuStart) && (Buffer < mSmramRanges[Index].CpuStart + mSmramRanges[Index].PhysicalSize)) ||\r
+        ((mSmramRanges[Index].CpuStart >= Buffer) && (mSmramRanges[Index].CpuStart < Buffer + Length))) {\r
+      return TRUE;\r
+    }\r
+  }\r
+\r
+  return FALSE;\r
+}\r
+\r
+/**\r
+  This function check if the address refered by Buffer and Length is valid.\r
+\r
+  @param Buffer  the buffer address to be checked.\r
+  @param Length  the buffer length to be checked.\r
+\r
+  @retval TRUE  this address is valid.\r
+  @retval FALSE this address is NOT valid.\r
+**/\r
+BOOLEAN\r
+InternalIsAddressValid (\r
+  IN UINTN                 Buffer,\r
+  IN UINTN                 Length\r
+  )\r
+{\r
+  if (Buffer > (MAX_ADDRESS - Length)) {\r
+    //\r
+    // Overflow happen\r
+    //\r
+    return FALSE;\r
+  }\r
+  if (InternalIsAddressInSmram ((EFI_PHYSICAL_ADDRESS)Buffer, (UINT64)Length)) {\r
+    return FALSE;\r
+  }\r
+  return TRUE;\r
+}\r
+\r
 /**\r
   Initializes a basic mutual exclusion lock.\r
 \r
@@ -232,6 +368,8 @@ GetFvbCountAndBuffer (
   *NumberHandles = BufferSize / sizeof(EFI_HANDLE);\r
   if (EFI_ERROR(Status)) {\r
     *NumberHandles = 0;\r
+    FreePool (*Buffer);\r
+    *Buffer = NULL;\r
   }\r
 \r
   return Status;\r
@@ -241,6 +379,9 @@ GetFvbCountAndBuffer (
 /**\r
   Get the variable statistics information from the information buffer pointed by gVariableInfo.\r
 \r
+  Caution: This function may be invoked at SMM runtime.\r
+  InfoEntry and InfoSize are external input. Care must be taken to make sure not security issue at runtime.\r
+\r
   @param[in, out]  InfoEntry    A pointer to the buffer of variable information entry.\r
                                 On input, point to the variable information returned last time. if \r
                                 InfoEntry->VendorGuid is zero, return the first information.\r
@@ -265,6 +406,7 @@ SmmVariableGetStatistics (
   UINTN                                                NameLength;\r
   UINTN                                                StatisticsInfoSize;\r
   CHAR16                                               *InfoName;\r
+  EFI_GUID                                             VendorGuid;\r
  \r
   if (InfoEntry == NULL) {\r
     return EFI_INVALID_PARAMETER;\r
@@ -276,13 +418,15 @@ SmmVariableGetStatistics (
   }\r
 \r
   StatisticsInfoSize = sizeof (VARIABLE_INFO_ENTRY) + StrSize (VariableInfo->Name);\r
-  if (*InfoSize < sizeof (VARIABLE_INFO_ENTRY)) {\r
+  if (*InfoSize < StatisticsInfoSize) {\r
     *InfoSize = StatisticsInfoSize;\r
     return EFI_BUFFER_TOO_SMALL;\r
   }\r
   InfoName = (CHAR16 *)(InfoEntry + 1);\r
 \r
-  if (CompareGuid (&InfoEntry->VendorGuid, &mZeroGuid)) {\r
+  CopyGuid (&VendorGuid, &InfoEntry->VendorGuid);\r
+\r
+  if (CompareGuid (&VendorGuid, &mZeroGuid)) {\r
     //\r
     // Return the first variable info\r
     //\r
@@ -296,7 +440,7 @@ SmmVariableGetStatistics (
   // Get the next variable info\r
   //\r
   while (VariableInfo != NULL) {\r
-    if (CompareGuid (&VariableInfo->VendorGuid, &InfoEntry->VendorGuid)) {\r
+    if (CompareGuid (&VariableInfo->VendorGuid, &VendorGuid)) {\r
       NameLength = StrSize (VariableInfo->Name);\r
       if (NameLength == StrSize (InfoName)) {\r
         if (CompareMem (VariableInfo->Name, InfoName, NameLength) == 0) {\r
@@ -338,6 +482,12 @@ SmmVariableGetStatistics (
 \r
   This SMI handler provides services for the variable wrapper driver.\r
 \r
+  Caution: This function may receive untrusted input.\r
+  This variable data and communicate buffer are external input, so this function will do basic validation.\r
+  Each sub function VariableServiceGetVariable(), VariableServiceGetNextVariableName(), \r
+  VariableServiceSetVariable(), VariableServiceQueryVariableInfo(), ReclaimForOS(), \r
+  SmmVariableGetStatistics() should also do validation based on its own knowledge.\r
+\r
   @param[in]     DispatchHandle  The unique handle assigned to this handler by SmiHandlerRegister().\r
   @param[in]     RegisterContext Points to an optional handler context which was specified when the\r
                                  handler was registered.\r
@@ -352,7 +502,6 @@ SmmVariableGetStatistics (
   @retval EFI_WARN_INTERRUPT_SOURCE_PENDING   The interrupt is still pending and other handlers should still \r
                                               be called.\r
   @retval EFI_INTERRUPT_PENDING               The interrupt could not be quiesced.\r
-  @retval EFI_INVALID_PARAMETER               Input parameter is invalid.\r
 \r
 **/\r
 EFI_STATUS\r
@@ -370,16 +519,77 @@ SmmVariableHandler (
   SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME  *GetNextVariableName;\r
   SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO     *QueryVariableInfo;\r
   VARIABLE_INFO_ENTRY                              *VariableInfo;\r
+  SMM_VARIABLE_COMMUNICATE_LOCK_VARIABLE           *VariableToLock;\r
   UINTN                                            InfoSize;\r
+  UINTN                                            NameBufferSize;\r
+  UINTN                                            CommBufferPayloadSize;\r
+  UINTN                                            TempCommBufferSize;\r
 \r
-  if (CommBuffer == NULL) {\r
-    return EFI_INVALID_PARAMETER;\r
+  //\r
+  // If input is invalid, stop processing this SMI\r
+  //\r
+  if (CommBuffer == NULL || CommBufferSize == NULL) {\r
+    return EFI_SUCCESS;\r
   }\r
 \r
+  TempCommBufferSize = *CommBufferSize;\r
+\r
+  if (TempCommBufferSize < SMM_VARIABLE_COMMUNICATE_HEADER_SIZE) {\r
+    DEBUG ((EFI_D_ERROR, "SmmVariableHandler: SMM communication buffer size invalid!\n"));\r
+    return EFI_SUCCESS;\r
+  }\r
+  CommBufferPayloadSize = TempCommBufferSize - SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;\r
+  if (CommBufferPayloadSize > mVariableBufferPayloadSize) {\r
+    DEBUG ((EFI_D_ERROR, "SmmVariableHandler: SMM communication buffer payload size invalid!\n"));\r
+    return EFI_SUCCESS;\r
+  }\r
+\r
+  if (!InternalIsAddressValid ((UINTN)CommBuffer, TempCommBufferSize)) {\r
+    DEBUG ((EFI_D_ERROR, "SmmVariableHandler: SMM communication buffer in SMRAM or overflow!\n"));\r
+    return EFI_SUCCESS;\r
+  }\r
+  \r
   SmmVariableFunctionHeader = (SMM_VARIABLE_COMMUNICATE_HEADER *)CommBuffer;\r
+    \r
   switch (SmmVariableFunctionHeader->Function) {\r
     case SMM_VARIABLE_FUNCTION_GET_VARIABLE:\r
-      SmmVariableHeader = (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE *) SmmVariableFunctionHeader->Data;     \r
+      if (CommBufferPayloadSize < OFFSET_OF(SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)) {\r
+        DEBUG ((EFI_D_ERROR, "GetVariable: SMM communication buffer size invalid!\n"));\r
+        return EFI_SUCCESS;\r
+      }\r
+      //\r
+      // Copy the input communicate buffer payload to pre-allocated SMM variable buffer payload.\r
+      //\r
+      CopyMem (mVariableBufferPayload, SmmVariableFunctionHeader->Data, CommBufferPayloadSize);\r
+      SmmVariableHeader = (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE *) mVariableBufferPayload;\r
+      if (((UINTN)(~0) - SmmVariableHeader->DataSize < OFFSET_OF(SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)) ||\r
+         ((UINTN)(~0) - SmmVariableHeader->NameSize < OFFSET_OF(SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) + SmmVariableHeader->DataSize)) {\r
+        //\r
+        // Prevent InfoSize overflow happen\r
+        //\r
+        Status = EFI_ACCESS_DENIED;\r
+        goto EXIT;\r
+      }\r
+      InfoSize = OFFSET_OF(SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) \r
+                 + SmmVariableHeader->DataSize + SmmVariableHeader->NameSize;\r
+\r
+      //\r
+      // SMRAM range check already covered before\r
+      //\r
+      if (InfoSize > CommBufferPayloadSize) {\r
+        DEBUG ((EFI_D_ERROR, "GetVariable: Data size exceed communication buffer size limit!\n"));\r
+        Status = EFI_ACCESS_DENIED;\r
+        goto EXIT;\r
+      }\r
+\r
+      if (SmmVariableHeader->NameSize < sizeof (CHAR16) || SmmVariableHeader->Name[SmmVariableHeader->NameSize/sizeof (CHAR16) - 1] != L'\0') {\r
+        //\r
+        // Make sure VariableName is A Null-terminated string.\r
+        //\r
+        Status = EFI_ACCESS_DENIED;\r
+        goto EXIT;\r
+      }\r
+\r
       Status = VariableServiceGetVariable (\r
                  SmmVariableHeader->Name,\r
                  &SmmVariableHeader->Guid,\r
@@ -387,19 +597,93 @@ SmmVariableHandler (
                  &SmmVariableHeader->DataSize,\r
                  (UINT8 *)SmmVariableHeader->Name + SmmVariableHeader->NameSize\r
                  );\r
+      CopyMem (SmmVariableFunctionHeader->Data, mVariableBufferPayload, CommBufferPayloadSize);\r
       break;\r
       \r
     case SMM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME:\r
-      GetNextVariableName = (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME *) SmmVariableFunctionHeader->Data;\r
+      if (CommBufferPayloadSize < OFFSET_OF(SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name)) {\r
+        DEBUG ((EFI_D_ERROR, "GetNextVariableName: SMM communication buffer size invalid!\n"));\r
+        return EFI_SUCCESS;\r
+      }\r
+      //\r
+      // Copy the input communicate buffer payload to pre-allocated SMM variable buffer payload.\r
+      //\r
+      CopyMem (mVariableBufferPayload, SmmVariableFunctionHeader->Data, CommBufferPayloadSize);\r
+      GetNextVariableName = (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME *) mVariableBufferPayload;\r
+      if ((UINTN)(~0) - GetNextVariableName->NameSize < OFFSET_OF(SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name)) {\r
+        //\r
+        // Prevent InfoSize overflow happen\r
+        //\r
+        Status = EFI_ACCESS_DENIED;\r
+        goto EXIT;\r
+      }\r
+      InfoSize = OFFSET_OF(SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name) + GetNextVariableName->NameSize;\r
+\r
+      //\r
+      // SMRAM range check already covered before\r
+      //\r
+      if (InfoSize > CommBufferPayloadSize) {\r
+        DEBUG ((EFI_D_ERROR, "GetNextVariableName: Data size exceed communication buffer size limit!\n"));\r
+        Status = EFI_ACCESS_DENIED;\r
+        goto EXIT;\r
+      }\r
+\r
+      NameBufferSize = CommBufferPayloadSize - OFFSET_OF(SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name);\r
+      if (NameBufferSize < sizeof (CHAR16) || GetNextVariableName->Name[NameBufferSize/sizeof (CHAR16) - 1] != L'\0') {\r
+        //\r
+        // Make sure input VariableName is A Null-terminated string.\r
+        //\r
+        Status = EFI_ACCESS_DENIED;\r
+        goto EXIT;\r
+      }\r
+\r
       Status = VariableServiceGetNextVariableName (\r
                  &GetNextVariableName->NameSize,\r
                  GetNextVariableName->Name,\r
                  &GetNextVariableName->Guid\r
                  );\r
+      CopyMem (SmmVariableFunctionHeader->Data, mVariableBufferPayload, CommBufferPayloadSize);\r
       break;\r
       \r
     case SMM_VARIABLE_FUNCTION_SET_VARIABLE:\r
-      SmmVariableHeader = (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE *) SmmVariableFunctionHeader->Data;\r
+      if (CommBufferPayloadSize < OFFSET_OF(SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)) {\r
+        DEBUG ((EFI_D_ERROR, "SetVariable: SMM communication buffer size invalid!\n"));\r
+        return EFI_SUCCESS;\r
+      }\r
+      //\r
+      // Copy the input communicate buffer payload to pre-allocated SMM variable buffer payload.\r
+      //\r
+      CopyMem (mVariableBufferPayload, SmmVariableFunctionHeader->Data, CommBufferPayloadSize);\r
+      SmmVariableHeader = (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE *) mVariableBufferPayload;\r
+      if (((UINTN)(~0) - SmmVariableHeader->DataSize < OFFSET_OF(SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)) ||\r
+         ((UINTN)(~0) - SmmVariableHeader->NameSize < OFFSET_OF(SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) + SmmVariableHeader->DataSize)) {\r
+        //\r
+        // Prevent InfoSize overflow happen\r
+        //\r
+        Status = EFI_ACCESS_DENIED;\r
+        goto EXIT;\r
+      }\r
+      InfoSize = OFFSET_OF(SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)\r
+                 + SmmVariableHeader->DataSize + SmmVariableHeader->NameSize;\r
+\r
+      //\r
+      // SMRAM range check already covered before\r
+      // Data buffer should not contain SMM range\r
+      //\r
+      if (InfoSize > CommBufferPayloadSize) {\r
+        DEBUG ((EFI_D_ERROR, "SetVariable: Data size exceed communication buffer size limit!\n"));\r
+        Status = EFI_ACCESS_DENIED;\r
+        goto EXIT;\r
+      }\r
+\r
+      if (SmmVariableHeader->NameSize < sizeof (CHAR16) || SmmVariableHeader->Name[SmmVariableHeader->NameSize/sizeof (CHAR16) - 1] != L'\0') {\r
+        //\r
+        // Make sure VariableName is A Null-terminated string.\r
+        //\r
+        Status = EFI_ACCESS_DENIED;\r
+        goto EXIT;\r
+      }\r
+\r
       Status = VariableServiceSetVariable (\r
                  SmmVariableHeader->Name,\r
                  &SmmVariableHeader->Guid,\r
@@ -410,7 +694,12 @@ SmmVariableHandler (
       break;\r
       \r
     case SMM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO:\r
+      if (CommBufferPayloadSize < sizeof (SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO)) {\r
+        DEBUG ((EFI_D_ERROR, "QueryVariableInfo: SMM communication buffer size invalid!\n"));\r
+        return EFI_SUCCESS;\r
+      }\r
       QueryVariableInfo = (SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO *) SmmVariableFunctionHeader->Data;\r
+  \r
       Status = VariableServiceQueryVariableInfo (\r
                  QueryVariableInfo->Attributes,\r
                  &QueryVariableInfo->MaximumVariableStorageSize,\r
@@ -420,6 +709,11 @@ SmmVariableHandler (
       break;\r
 \r
     case SMM_VARIABLE_FUNCTION_READY_TO_BOOT:\r
+      mEndOfDxe = TRUE;\r
+      if (AtRuntime()) {\r
+        Status = EFI_UNSUPPORTED;\r
+        break;\r
+      }\r
       ReclaimForOS ();\r
       Status = EFI_SUCCESS;\r
       break;\r
@@ -431,21 +725,68 @@ SmmVariableHandler (
 \r
     case SMM_VARIABLE_FUNCTION_GET_STATISTICS:\r
       VariableInfo = (VARIABLE_INFO_ENTRY *) SmmVariableFunctionHeader->Data;\r
-      InfoSize = *CommBufferSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_HEADER, Data);\r
+      InfoSize = TempCommBufferSize - SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;\r
+\r
+      //\r
+      // Do not need to check SmmVariableFunctionHeader->Data in SMRAM here. \r
+      // It is covered by previous CommBuffer check \r
+      //\r
+     \r
+      if (InternalIsAddressInSmram ((EFI_PHYSICAL_ADDRESS)(UINTN)CommBufferSize, sizeof(UINTN))) {\r
+        DEBUG ((EFI_D_ERROR, "GetStatistics: SMM communication buffer in SMRAM!\n"));\r
+        Status = EFI_ACCESS_DENIED;\r
+        goto EXIT;\r
+      }  \r
+\r
       Status = SmmVariableGetStatistics (VariableInfo, &InfoSize);\r
-      *CommBufferSize = InfoSize + OFFSET_OF (SMM_VARIABLE_COMMUNICATE_HEADER, Data);\r
+      *CommBufferSize = InfoSize + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;\r
+      break;\r
+\r
+    case SMM_VARIABLE_FUNCTION_LOCK_VARIABLE:\r
+      if (mEndOfDxe) {\r
+        Status = EFI_ACCESS_DENIED;\r
+      } else {\r
+        VariableToLock = (SMM_VARIABLE_COMMUNICATE_LOCK_VARIABLE *) SmmVariableFunctionHeader->Data;\r
+        Status = VariableLockRequestToLock (\r
+                   NULL,\r
+                   VariableToLock->Name,\r
+                   &VariableToLock->Guid\r
+                   );\r
+      }\r
       break;\r
 \r
     default:\r
-      ASSERT (FALSE);\r
       Status = EFI_UNSUPPORTED;\r
   }\r
 \r
-  SmmVariableFunctionHeader->ReturnStatus = Status;\r
+EXIT:\r
 \r
+  SmmVariableFunctionHeader->ReturnStatus = Status;\r
   return EFI_SUCCESS;\r
 }\r
 \r
+/**\r
+  SMM END_OF_DXE protocol notification event handler.\r
+\r
+  @param  Protocol   Points to the protocol's unique identifier\r
+  @param  Interface  Points to the interface instance\r
+  @param  Handle     The handle on which the interface was installed\r
+\r
+  @retval EFI_SUCCESS   SmmEndOfDxeCallback runs successfully\r
+\r
+**/\r
+EFI_STATUS\r
+EFIAPI\r
+SmmEndOfDxeCallback (\r
+  IN CONST EFI_GUID                       *Protocol,\r
+  IN VOID                                 *Interface,\r
+  IN EFI_HANDLE                           Handle\r
+  )\r
+{\r
+  DEBUG ((EFI_D_INFO, "[Variable]END_OF_DXE is signaled\n"));\r
+  mEndOfDxe = TRUE;\r
+  return EFI_SUCCESS;\r
+}\r
 \r
 /**\r
   SMM Fault Tolerant Write protocol notification event handler.\r
@@ -473,6 +814,7 @@ SmmFtwNotificationEvent (
   EFI_SMM_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *FvbProtocol;\r
   EFI_SMM_FAULT_TOLERANT_WRITE_PROTOCOL   *FtwProtocol;\r
   EFI_PHYSICAL_ADDRESS                    NvStorageVariableBase;\r
+  UINTN                                   FtwMaxBlockSize;\r
   \r
   if (mVariableModuleGlobal->FvbInstance != NULL) {\r
     return EFI_SUCCESS;\r
@@ -486,6 +828,11 @@ SmmFtwNotificationEvent (
     return Status;\r
   }\r
 \r
+  Status = FtwProtocol->GetMaxBlockSize (FtwProtocol, &FtwMaxBlockSize);\r
+  if (!EFI_ERROR (Status)) {\r
+    ASSERT (PcdGet32 (PcdFlashNvStorageVariableSize) <= FtwMaxBlockSize);\r
+  }\r
+\r
   //\r
   // Find the proper FVB protocol for variable.\r
   //\r
@@ -501,7 +848,9 @@ SmmFtwNotificationEvent (
   mVariableModuleGlobal->FvbInstance = FvbProtocol;\r
   \r
   Status = VariableWriteServiceInitialize ();\r
-  ASSERT_EFI_ERROR (Status);\r
+  if (EFI_ERROR (Status)) {\r
+    DEBUG ((DEBUG_ERROR, "Variable write service initialization failed. Status = %r\n", Status));\r
+  }\r
  \r
   //\r
   // Notify the variable wrapper driver the variable write service is ready\r
@@ -540,7 +889,10 @@ VariableServiceInitialize (
   EFI_STATUS                              Status;\r
   EFI_HANDLE                              VariableHandle;\r
   VOID                                    *SmmFtwRegistration;\r
-  \r
+  EFI_SMM_ACCESS2_PROTOCOL                *SmmAccess;\r
+  UINTN                                   Size;\r
+  VOID                                    *SmmEndOfDxeRegistration;\r
+\r
   //\r
   // Variable initialize.\r
   //\r
@@ -559,6 +911,38 @@ VariableServiceInitialize (
                     );\r
   ASSERT_EFI_ERROR (Status);\r
 \r
+  //\r
+  // Get SMRAM information\r
+  //\r
+  Status = gBS->LocateProtocol (&gEfiSmmAccess2ProtocolGuid, NULL, (VOID **)&SmmAccess);\r
+  ASSERT_EFI_ERROR (Status);\r
+\r
+  Size = 0;\r
+  Status = SmmAccess->GetCapabilities (SmmAccess, &Size, NULL);\r
+  ASSERT (Status == EFI_BUFFER_TOO_SMALL);\r
+\r
+  Status = gSmst->SmmAllocatePool (\r
+                    EfiRuntimeServicesData,\r
+                    Size,\r
+                    (VOID **)&mSmramRanges\r
+                    );\r
+  ASSERT_EFI_ERROR (Status);\r
+\r
+  Status = SmmAccess->GetCapabilities (SmmAccess, &Size, mSmramRanges);\r
+  ASSERT_EFI_ERROR (Status);\r
+\r
+  mSmramRangeCount = Size / sizeof (EFI_SMRAM_DESCRIPTOR);\r
+\r
+  mVariableBufferPayloadSize = MAX (PcdGet32 (PcdMaxVariableSize), PcdGet32 (PcdMaxHardwareErrorVariableSize)) +\r
+                               OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) - sizeof (VARIABLE_HEADER);\r
+\r
+  Status = gSmst->SmmAllocatePool (\r
+                    EfiRuntimeServicesData,\r
+                    mVariableBufferPayloadSize,\r
+                    (VOID **)&mVariableBufferPayload\r
+                    );\r
+  ASSERT_EFI_ERROR (Status);\r
+\r
   ///\r
   /// Register SMM variable SMI handler\r
   ///\r
@@ -577,6 +961,16 @@ VariableServiceInitialize (
                                         );\r
   ASSERT_EFI_ERROR (Status);\r
  \r
+  //\r
+  // Register EFI_SMM_END_OF_DXE_PROTOCOL_GUID notify function.\r
+  //\r
+  Status = gSmst->SmmRegisterProtocolNotify (\r
+                    &gEfiSmmEndOfDxeProtocolGuid,\r
+                    SmmEndOfDxeCallback,\r
+                    &SmmEndOfDxeRegistration\r
+                    );\r
+  ASSERT_EFI_ERROR (Status);\r
+\r
   //\r
   // Register FtwNotificationEvent () notify function.\r
   // \r