Add SMRAM range check to variable SMM SMI handler.

Signed-off-by: Chao Zhang <chao.b.zhang@intel.com>
Reviewed-by: Fu, Siyuan<siyuan.fu@intel.com>

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13530 6f19259b-4bc3-4df7-8a09-765794883524

2 files changed, 166 insertions, 22 deletions

diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
index 8d949c3965..d4403a2530 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
@@ -4,11 +4,22 @@
   implements  an SMI handler to communicate with the DXE runtime driver 

   to provide variable services.

 

-Copyright (c) 2010 - 2011, 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                                            

+  Caution: This module requires additional review when modified.

+  This driver will have external input - variable data and communicate buffer in SMM mode.

+  This external input must be validated carefully to avoid security issue like

+  buffer overflow, integer overflow.

+

+  SmmVariableHandler() will receive untrusted input and do basic validation.

+

+  Each sub function VariableServiceGetVariable(), VariableServiceGetNextVariableName(), 

+  VariableServiceSetVariable(), VariableServiceQueryVariableInfo(), ReclaimForOS(), 

+  SmmVariableGetStatistics() should also do validation based on its own knowledge.

+

+Copyright (c) 2010 - 2012, 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.  

@@ -17,12 +28,17 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #include <Protocol/SmmVariable.h>

 #include <Protocol/SmmFirmwareVolumeBlock.h>

 #include <Protocol/SmmFaultTolerantWrite.h>

+#include <Protocol/SmmAccess2.h>

+

 #include <Library/SmmServicesTableLib.h>

 

 #include <Guid/VariableFormat.h>

 #include <Guid/SmmVariableCommon.h>

 #include "Variable.h"

 

+EFI_SMRAM_DESCRIPTOR                                 *mSmramRanges;

+UINTN                                                mSmramRangeCount;

+

 extern VARIABLE_INFO_ENTRY                           *gVariableInfo;

 EFI_HANDLE                                           mSmmVariableHandle      = NULL;

 EFI_HANDLE                                           mVariableHandle         = NULL;

@@ -51,6 +67,34 @@ AtRuntime (
 }

 

 /**

+  This function check if the address is in SMRAM.

+

+  @param Buffer  the buffer address to be checked.

+  @param Length  the buffer length to be checked.

+

+  @retval TRUE  this address is in SMRAM.

+  @retval FALSE this address is NOT in SMRAM.

+**/

+BOOLEAN

+InternalIsAddressInSmram (

+  IN EFI_PHYSICAL_ADDRESS  Buffer,

+  IN UINT64                Length

+  )

+{

+  UINTN  Index;

+

+  for (Index = 0; Index < mSmramRangeCount; Index ++) {

+    if (((Buffer >= mSmramRanges[Index].CpuStart) && (Buffer < mSmramRanges[Index].CpuStart + mSmramRanges[Index].PhysicalSize)) ||

+        ((mSmramRanges[Index].CpuStart >= Buffer) && (mSmramRanges[Index].CpuStart < Buffer + Length))) {

+      return TRUE;

+    }

+  }

+

+  return FALSE;

+}

+

+

+/**

   Initializes a basic mutual exclusion lock.

 

   This function initializes a basic mutual exclusion lock to the released state 

@@ -241,12 +285,15 @@ GetFvbCountAndBuffer (
 /**

   Get the variable statistics information from the information buffer pointed by gVariableInfo.

 

-  @param[in, out]  InfoEntry   A pointer to the buffer of variable information entry.

-                               On input, point to the variable information returned last time. if 

-                               InfoEntry->VendorGuid is zero, return the first information.

-                               On output, point to the next variable information.

-  @param[in, out]  InfoSize    On input, the size of the variable information buffer.

-                               On output, the returned variable information size.

+  Caution: This function may be invoked at SMM runtime.

+  InfoEntry and InfoSize are external input. Care must be taken to make sure not security issue at runtime.

+

+  @param[in, out]  InfoEntry    A pointer to the buffer of variable information entry.

+                                On input, point to the variable information returned last time. if 

+                                InfoEntry->VendorGuid is zero, return the first information.

+                                On output, point to the next variable information.

+  @param[in, out]  InfoSize     On input, the size of the variable information buffer.

+                                On output, the returned variable information size.

 

   @retval EFI_SUCCESS          The variable information is found and returned successfully.

   @retval EFI_UNSUPPORTED      No variable inoformation exists in variable driver. The 

@@ -334,6 +381,12 @@ SmmVariableGetStatistics (
 

   This SMI handler provides services for the variable wrapper driver.

 

+  Caution: This function may receive untrusted input.

+  This variable data and communicate buffer are external input, so this function will do basic validation.

+  Each sub function VariableServiceGetVariable(), VariableServiceGetNextVariableName(), 

+  VariableServiceSetVariable(), VariableServiceQueryVariableInfo(), ReclaimForOS(), 

+  SmmVariableGetStatistics() should also do validation based on its own knowledge.

+

   @param[in]     DispatchHandle  The unique handle assigned to this handler by SmiHandlerRegister().

   @param[in]     RegisterContext Points to an optional handler context which was specified when the

                                  handler was registered.

@@ -366,12 +419,38 @@ SmmVariableHandler (
   VARIABLE_INFO_ENTRY                              *VariableInfo;

   UINTN                                            InfoSize;

 

-  ASSERT (CommBuffer != NULL);

+  //

+  // If input is invalid, stop processing this SMI

+  //

+  if (CommBuffer == NULL || CommBufferSize == NULL) {

+    return EFI_SUCCESS;

+  }

+

+  if (*CommBufferSize < sizeof(SMM_VARIABLE_COMMUNICATE_HEADER) - 1) {

+    return EFI_SUCCESS;

+  }

+

+  if (InternalIsAddressInSmram ((EFI_PHYSICAL_ADDRESS)(UINTN)CommBuffer, *CommBufferSize)) {

+    DEBUG ((EFI_D_ERROR, "SMM communication buffer size is in SMRAM!\n"));

+    return EFI_SUCCESS;

+  }

 

   SmmVariableFunctionHeader = (SMM_VARIABLE_COMMUNICATE_HEADER *)CommBuffer;

   switch (SmmVariableFunctionHeader->Function) {

     case SMM_VARIABLE_FUNCTION_GET_VARIABLE:

-      SmmVariableHeader = (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE *) SmmVariableFunctionHeader->Data;     

+      SmmVariableHeader = (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE *) SmmVariableFunctionHeader->Data;

+      InfoSize = OFFSET_OF(SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) 

+                 + SmmVariableHeader->DataSize + SmmVariableHeader->NameSize;

+

+      //

+      // SMRAM range check already covered before

+      //

+      if (InfoSize > *CommBufferSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_HEADER, Data)) {

+        DEBUG ((EFI_D_ERROR, "Data size exceed communication buffer size limit!\n"));

+        Status = EFI_ACCESS_DENIED;

+        goto EXIT;

+      }

+

       Status = VariableServiceGetVariable (

                  SmmVariableHeader->Name,

                  &SmmVariableHeader->Guid,

@@ -383,6 +462,17 @@ SmmVariableHandler (
       

     case SMM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME:

       GetNextVariableName = (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME *) SmmVariableFunctionHeader->Data;

+      InfoSize = OFFSET_OF(SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name) + GetNextVariableName->NameSize;

+

+      //

+      // SMRAM range check already covered before

+      //

+      if (InfoSize > *CommBufferSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_HEADER, Data)) {

+        DEBUG ((EFI_D_ERROR, "Data size exceed communication buffer size limit!\n"));

+        Status = EFI_ACCESS_DENIED;

+        goto EXIT;

+      }

+

       Status = VariableServiceGetNextVariableName (

                  &GetNextVariableName->NameSize,

                  GetNextVariableName->Name,

@@ -403,6 +493,17 @@ SmmVariableHandler (
       

     case SMM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO:

       QueryVariableInfo = (SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO *) SmmVariableFunctionHeader->Data;

+      InfoSize = sizeof(SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO);

+

+      //

+      // SMRAM range check already covered before

+      //

+      if (InfoSize > *CommBufferSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_HEADER, Data)) {

+        DEBUG ((EFI_D_ERROR, "Data size exceed communication buffer size limit!\n"));

+        Status = EFI_ACCESS_DENIED;

+        goto EXIT;

+      }

+

       Status = VariableServiceQueryVariableInfo (

                  QueryVariableInfo->Attributes,

                  &QueryVariableInfo->MaximumVariableStorageSize,

@@ -424,15 +525,28 @@ SmmVariableHandler (
     case SMM_VARIABLE_FUNCTION_GET_STATISTICS:

       VariableInfo = (VARIABLE_INFO_ENTRY *) SmmVariableFunctionHeader->Data;

       InfoSize = *CommBufferSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_HEADER, Data);

+

+      //

+      // Do not need to check SmmVariableFunctionHeader->Data in SMRAM here. 

+      // It is covered by previous CommBuffer check 

+      //

+     

+      if (InternalIsAddressInSmram ((EFI_PHYSICAL_ADDRESS)(UINTN)CommBufferSize, sizeof(UINTN))) {

+        DEBUG ((EFI_D_ERROR, "SMM communication buffer size is in SMRAM!\n"));

+        Status = EFI_ACCESS_DENIED;

+        goto EXIT;

+      }  

+

       Status = SmmVariableGetStatistics (VariableInfo, &InfoSize);

       *CommBufferSize = InfoSize + OFFSET_OF (SMM_VARIABLE_COMMUNICATE_HEADER, Data);

       break;

 

     default:

-      ASSERT (FALSE);

       Status = EFI_UNSUPPORTED;

   }

 

+EXIT:

+

   SmmVariableFunctionHeader->ReturnStatus = Status;

 

   return EFI_SUCCESS;

@@ -532,7 +646,9 @@ VariableServiceInitialize (
   EFI_STATUS                              Status;

   EFI_HANDLE                              VariableHandle;

   VOID                                    *SmmFtwRegistration;

-  

+  EFI_SMM_ACCESS2_PROTOCOL                *SmmAccess;

+  UINTN                                   Size;

+

   //

   // Variable initialize.

   //

@@ -551,6 +667,28 @@ VariableServiceInitialize (
                     );

   ASSERT_EFI_ERROR (Status);

 

+  //

+  // Get SMRAM information

+  //

+  Status = gBS->LocateProtocol (&gEfiSmmAccess2ProtocolGuid, NULL, (VOID **)&SmmAccess);

+  ASSERT_EFI_ERROR (Status);

+

+  Size = 0;

+  Status = SmmAccess->GetCapabilities (SmmAccess, &Size, NULL);

+  ASSERT (Status == EFI_BUFFER_TOO_SMALL);

+

+  Status = gSmst->SmmAllocatePool (

+                    EfiRuntimeServicesData,

+                    Size,

+                    (VOID **)&mSmramRanges

+                    );

+  ASSERT_EFI_ERROR (Status);

+

+  Status = SmmAccess->GetCapabilities (SmmAccess, &Size, mSmramRanges);

+  ASSERT_EFI_ERROR (Status);

+

+  mSmramRangeCount = Size / sizeof (EFI_SMRAM_DESCRIPTOR);

+

   ///

   /// Register SMM variable SMI handler

   ///

diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
index da0a0e9ff8..11009c299c 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.inf
@@ -8,14 +8,19 @@
 #  This module should be used with SMM Runtime DXE module together. The 
 #  SMM Runtime DXE module would install variable arch protocol and variable 
 #  write arch protocol based on SMM variable module.
-# Copyright (c) 2010 - 2012, 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.
+#  Caution: This module requires additional review when modified.
+#  This driver will have external input - variable data and communicate buffer in SMM mode.
+#  This external input must be validated carefully to avoid security issue like
+#  buffer overflow, integer overflow.
+#
+# Copyright (c) 2010 - 2012, 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.
 #
 #
 ##
@@ -62,6 +67,7 @@
   gEfiSmmFirmwareVolumeBlockProtocolGuid        ## SOMETIMES_CONSUMES
   gEfiSmmVariableProtocolGuid                   ## ALWAYS_PRODUCES
   gEfiSmmFaultTolerantWriteProtocolGuid         ## SOMETIMES_CONSUMES
+  gEfiSmmAccess2ProtocolGuid                    ## ALWAYS_CONSUMES
 
 [Guids]
   gEfiVariableGuid                              ## PRODUCES ## Configuration Table Guid