From bdc9d5a5d5b22bb96e075e04211c450f76bef595 Mon Sep 17 00:00:00 2001
From: lgao4 <lgao4@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Mon, 19 Dec 2011 09:00:58 +0000
Subject: [PATCH] Add more check to make sure the valid pointer be used.
 Signed-off-by: lgao4 Reviewed-by: rsun3

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12886 6f19259b-4bc3-4df7-8a09-765794883524
---
 MdeModulePkg/Core/Dxe/Dispatcher/Dispatcher.c | 56 ++++++++++---------
 1 file changed, 29 insertions(+), 27 deletions(-)

diff --git a/MdeModulePkg/Core/Dxe/Dispatcher/Dispatcher.c b/MdeModulePkg/Core/Dxe/Dispatcher/Dispatcher.c
index 5f8e383158..16fd793c12 100644
--- a/MdeModulePkg/Core/Dxe/Dispatcher/Dispatcher.c
+++ b/MdeModulePkg/Core/Dxe/Dispatcher/Dispatcher.c
@@ -745,40 +745,42 @@ FvIsBeingProcesssed (
     //
     // Get the full FV header based on FVB protocol.
     //
+    ASSERT (Fvb != NULL);
     Status = GetFwVolHeader (Fvb, &FwVolHeader);
-    if (EFI_ERROR (Status)) {
-      FwVolHeader = NULL;
-    } else if (VerifyFvHeaderChecksum (FwVolHeader) && FwVolHeader->ExtHeaderOffset != 0) {
-      ExtHeaderOffset = (UINT32) FwVolHeader->ExtHeaderOffset;
-      BlockMap  = FwVolHeader->BlockMap;
-      LbaIndex  = 0;
-      LbaOffset = 0;
-      //
-      // Find LbaIndex and LbaOffset for FV extension header based on BlockMap.
-      //
-      while ((BlockMap->NumBlocks != 0) || (BlockMap->Length != 0)) {
-        for (Index = 0; Index < BlockMap->NumBlocks && ExtHeaderOffset >= BlockMap->Length; Index ++) {
-          ExtHeaderOffset -= BlockMap->Length;
-          LbaIndex ++;
+    if (!EFI_ERROR (Status)) {
+      ASSERT (FwVolHeader != NULL);
+      if (VerifyFvHeaderChecksum (FwVolHeader) && FwVolHeader->ExtHeaderOffset != 0) {
+        ExtHeaderOffset = (UINT32) FwVolHeader->ExtHeaderOffset;
+        BlockMap  = FwVolHeader->BlockMap;
+        LbaIndex  = 0;
+        LbaOffset = 0;
+        //
+        // Find LbaIndex and LbaOffset for FV extension header based on BlockMap.
+        //
+        while ((BlockMap->NumBlocks != 0) || (BlockMap->Length != 0)) {
+          for (Index = 0; Index < BlockMap->NumBlocks && ExtHeaderOffset >= BlockMap->Length; Index ++) {
+            ExtHeaderOffset -= BlockMap->Length;
+            LbaIndex ++;
+          }
+          //
+          // Check whether FvExtHeader is crossing the multi block range.
+          //
+          if (Index < BlockMap->NumBlocks) {
+            LbaOffset = ExtHeaderOffset;
+            break;
+          }
+          BlockMap++;
         }
         //
-        // Check whether FvExtHeader is crossing the multi block range.
+        // Read FvNameGuid from FV extension header.
         //
-        if (Index < BlockMap->NumBlocks) {
-          LbaOffset = ExtHeaderOffset;
-          break;
+        Status = ReadFvbData (Fvb, &LbaIndex, &LbaOffset, sizeof (FvNameGuid), (UINT8 *) &FvNameGuid);
+        if (!EFI_ERROR (Status)) {
+          FvNameGuidIsFound = TRUE;
         }
-        BlockMap++;
-      }
-      //
-      // Read FvNameGuid from FV extension header.
-      //
-      Status = ReadFvbData (Fvb, &LbaIndex, &LbaOffset, sizeof (FvNameGuid), (UINT8 *) &FvNameGuid);
-      if (!EFI_ERROR (Status)) {
-        FvNameGuidIsFound = TRUE;
       }
+      CoreFreePool (FwVolHeader);
     }
-    CoreFreePool (FwVolHeader);
   }
 
   if (FvNameGuidIsFound) {