IntelSiliconPkg IntelVTdDxe: Fix potential NULL pointer dereference

[mirror_edk2.git] / IntelSiliconPkg / Feature / VTd / IntelVTdDxe / DmarAcpiTable.c

diff --git a/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c b/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
index 39b70a134e1e8a41a5acd88377c5f73d5fa6fa73..342830a01fb05135706b610c8225fac98ab5eb78 100644 (file)
--- a/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
+++ b/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
@@ -1,6 +1,6 @@
 /** @file\r
 \r
-  Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>\r
+  Copyright (c) 2017 - 2018, 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
@@ -27,7 +27,7 @@ typedef struct {
 \r
 #pragma pack()\r
 \r
-EFI_ACPI_DMAR_HEADER  *mAcpiDmarTable;\r
+EFI_ACPI_DMAR_HEADER  *mAcpiDmarTable = NULL;\r
 \r
 /**\r
   Dump DMAR DeviceScopeEntry.\r
@@ -889,7 +889,7 @@ ScanTableInRSDT (
   EntryPtr = &Rsdt->Entry;\r
   for (Index = 0; Index < EntryCount; Index ++, EntryPtr ++) {\r
     Table = (EFI_ACPI_DESCRIPTION_HEADER*)((UINTN)(*EntryPtr));\r
-    if (Table->Signature == Signature) {\r
+    if ((Table != NULL) && (Table->Signature == Signature)) {\r
       return Table;\r
     }\r
   }\r
@@ -923,7 +923,7 @@ ScanTableInXSDT (
   for (Index = 0; Index < EntryCount; Index ++) {\r
     CopyMem (&EntryPtr, (VOID *)(BasePtr + Index * sizeof(UINT64)), sizeof(UINT64));\r
     Table = (EFI_ACPI_DESCRIPTION_HEADER*)((UINTN)(EntryPtr));\r
-    if (Table->Signature == Signature) {\r
+    if ((Table != NULL) && (Table->Signature == Signature)) {\r
       return Table;\r
     }\r
   }\r
@@ -978,8 +978,9 @@ FindAcpiPtr (
 /**\r
   Get the DMAR ACPI table.\r
 \r
-  @retval EFI_SUCCESS    The DMAR ACPI table is got.\r
-  @retval EFI_NOT_FOUND  The DMAR ACPI table is not found.\r
+  @retval EFI_SUCCESS           The DMAR ACPI table is got.\r
+  @retval EFI_ALREADY_STARTED   The DMAR ACPI table has been got previously.\r
+  @retval EFI_NOT_FOUND         The DMAR ACPI table is not found.\r
 **/\r
 EFI_STATUS\r
 GetDmarAcpiTable (\r
@@ -989,6 +990,10 @@ GetDmarAcpiTable (
   VOID                              *AcpiTable;\r
   EFI_STATUS                        Status;\r
 \r
+  if (mAcpiDmarTable != NULL) {\r
+    return EFI_ALREADY_STARTED;\r
+  }\r
+\r
   AcpiTable = NULL;\r
   Status = EfiGetSystemConfigurationTable (\r
              &gEfiAcpi20TableGuid,\r
@@ -1000,16 +1005,19 @@ GetDmarAcpiTable (
                &AcpiTable\r
                );\r
   }\r
+  if (EFI_ERROR (Status)) {\r
+    return EFI_NOT_FOUND;\r
+  }\r
   ASSERT (AcpiTable != NULL);\r
 \r
   mAcpiDmarTable = FindAcpiPtr (\r
                       (EFI_ACPI_2_0_ROOT_SYSTEM_DESCRIPTION_POINTER *)AcpiTable,\r
                       EFI_ACPI_4_0_DMA_REMAPPING_TABLE_SIGNATURE\r
                       );\r
-  DEBUG ((DEBUG_INFO,"DMAR Table - 0x%08x\n", mAcpiDmarTable));\r
   if (mAcpiDmarTable == NULL) {\r
-    return EFI_UNSUPPORTED;\r
+    return EFI_NOT_FOUND;\r
   }\r
+  DEBUG ((DEBUG_INFO,"DMAR Table - 0x%08x\n", mAcpiDmarTable));\r
   VtdDumpDmarTable();\r
 \r
   return EFI_SUCCESS;\r