IntelSiliconPkg IntelVTdDxe: Fix potential NULL pointer dereference

[edk2] [PATCH] IntelSiliconPkg IntelVTdDxe: Fix potential NULL pointer dereference

Posted by Star Zeng 6 years, 11 months ago

The implementation of MdeModulePkg\Universal\Acpi\AcpiTableDxe reserves
first entry of RSDT/XSDT to FADT, the first entry value is 0 when FADT
is installed. So the RSDT/XSDT parsing code should check the entry value
first before checking the table signature.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Star Zeng <star.zeng@intel.com>
---
 IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c b/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
index b981bcdb3aa0..342830a01fb0 100644
--- a/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
+++ b/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
@@ -1,6 +1,6 @@
 /** @file
 
-  Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2017 - 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
@@ -889,7 +889,7 @@ ScanTableInRSDT (
   EntryPtr = &Rsdt->Entry;
   for (Index = 0; Index < EntryCount; Index ++, EntryPtr ++) {
     Table = (EFI_ACPI_DESCRIPTION_HEADER*)((UINTN)(*EntryPtr));
-    if (Table->Signature == Signature) {
+    if ((Table != NULL) && (Table->Signature == Signature)) {
       return Table;
     }
   }
@@ -923,7 +923,7 @@ ScanTableInXSDT (
   for (Index = 0; Index < EntryCount; Index ++) {
     CopyMem (&EntryPtr, (VOID *)(BasePtr + Index * sizeof(UINT64)), sizeof(UINT64));
     Table = (EFI_ACPI_DESCRIPTION_HEADER*)((UINTN)(EntryPtr));
-    if (Table->Signature == Signature) {
+    if ((Table != NULL) && (Table->Signature == Signature)) {
       return Table;
     }
   }
-- 
2.7.0.windows.1

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Re: [edk2] [PATCH] IntelSiliconPkg IntelVTdDxe: Fix potential NULL pointer dereference

Posted by Yao, Jiewen 6 years, 11 months ago

Reviewed-by: Jiewen.yao@intel.com

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Star
> Zeng
> Sent: Monday, January 15, 2018 10:35 AM
> To: edk2-devel@lists.01.org
> Cc: Yao, Jiewen <jiewen.yao@intel.com>; Zeng, Star <star.zeng@intel.com>
> Subject: [edk2] [PATCH] IntelSiliconPkg IntelVTdDxe: Fix potential NULL pointer
> dereference
> 
> The implementation of MdeModulePkg\Universal\Acpi\AcpiTableDxe reserves
> first entry of RSDT/XSDT to FADT, the first entry value is 0 when FADT
> is installed. So the RSDT/XSDT parsing code should check the entry value
> first before checking the table signature.
> 
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Star Zeng <star.zeng@intel.com>
> ---
>  IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
> b/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
> index b981bcdb3aa0..342830a01fb0 100644
> --- a/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
> +++ b/IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmarAcpiTable.c
> @@ -1,6 +1,6 @@
>  /** @file
> 
> -  Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
> +  Copyright (c) 2017 - 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
> @@ -889,7 +889,7 @@ ScanTableInRSDT (
>    EntryPtr = &Rsdt->Entry;
>    for (Index = 0; Index < EntryCount; Index ++, EntryPtr ++) {
>      Table = (EFI_ACPI_DESCRIPTION_HEADER*)((UINTN)(*EntryPtr));
> -    if (Table->Signature == Signature) {
> +    if ((Table != NULL) && (Table->Signature == Signature)) {
>        return Table;
>      }
>    }
> @@ -923,7 +923,7 @@ ScanTableInXSDT (
>    for (Index = 0; Index < EntryCount; Index ++) {
>      CopyMem (&EntryPtr, (VOID *)(BasePtr + Index * sizeof(UINT64)),
> sizeof(UINT64));
>      Table = (EFI_ACPI_DESCRIPTION_HEADER*)((UINTN)(EntryPtr));
> -    if (Table->Signature == Signature) {
> +    if ((Table != NULL) && (Table->Signature == Signature)) {
>        return Table;
>      }
>    }
> --
> 2.7.0.windows.1
> 
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> edk2-devel@lists.01.org
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