MdeModulePkg/SmmCore: Fix hang due to already-freed memory deference

SmiHandlerUnRegister() validates the DispatchHandle by checking
whether the first 32bit matches to a certain signature
(SMI_HANDLER_SIGNATURE).
But if a caller calls *UnRegister() twice and the memory freed by
first call still contains the signature, the second call may hang.

The patch fixes this issue by locating the DispatchHandle
in all SMI handlers, instead of checking the signature.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>

1 files changed, 32 insertions, 5 deletions

diff --git a/MdeModulePkg/Core/PiSmmCore/Smi.c b/MdeModulePkg/Core/PiSmmCore/Smi.c
index ad483a1..0c09e7f 100644
--- a/MdeModulePkg/Core/PiSmmCore/Smi.c
+++ b/MdeModulePkg/Core/PiSmmCore/Smi.c
@@ -1,7 +1,7 @@
 /** @file

   SMI management.

 

-  Copyright (c) 2009 - 2017, Intel Corporation. All rights reserved.<BR>

+  Copyright (c) 2009 - 2018, 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        

@@ -276,14 +276,41 @@ SmiHandlerUnRegister (
 {

   SMI_HANDLER  *SmiHandler;

   SMI_ENTRY    *SmiEntry;

+  LIST_ENTRY   *EntryLink;

+  LIST_ENTRY   *HandlerLink;

 

-  SmiHandler = (SMI_HANDLER *) DispatchHandle;

-

-  if (SmiHandler == NULL) {

+  if (DispatchHandle == NULL) {

     return EFI_INVALID_PARAMETER;

   }

 

-  if (SmiHandler->Signature != SMI_HANDLER_SIGNATURE) {

+  //

+  // Look for it in root SMI handlers

+  //

+  SmiHandler = NULL;

+  for ( HandlerLink = GetFirstNode (&mRootSmiEntry.SmiHandlers)

+      ; !IsNull (&mRootSmiEntry.SmiHandlers, HandlerLink) && (SmiHandler != DispatchHandle)

+      ; HandlerLink = GetNextNode (&mRootSmiEntry.SmiHandlers, HandlerLink)

+      ) {

+    SmiHandler = CR (HandlerLink, SMI_HANDLER, Link, SMI_HANDLER_SIGNATURE);

+  }

+

+  //

+  // Look for it in non-root SMI handlers

+  //

+  for ( EntryLink = GetFirstNode (&mSmiEntryList)

+      ; !IsNull (&mSmiEntryList, EntryLink) && (SmiHandler != DispatchHandle)

+      ; EntryLink = GetNextNode (&mSmiEntryList, EntryLink)

+      ) {

+    SmiEntry = CR (EntryLink, SMI_ENTRY, AllEntries, SMI_ENTRY_SIGNATURE);

+    for ( HandlerLink = GetFirstNode (&SmiEntry->SmiHandlers)

+        ; !IsNull (&SmiEntry->SmiHandlers, HandlerLink) && (SmiHandler != DispatchHandle)

+        ; HandlerLink = GetNextNode (&SmiEntry->SmiHandlers, HandlerLink)

+        ) {

+      SmiHandler = CR (HandlerLink, SMI_HANDLER, Link, SMI_HANDLER_SIGNATURE);

+    }

+  }

+

+  if (SmiHandler != DispatchHandle) {

     return EFI_INVALID_PARAMETER;

   }