MdeModulePkg/DxeCore: ignore PdbPointer if ImageAddress == 0

[edk2] [PATCH] MdeModulePkg/DxeCore: ignore PdbPointer if ImageAddress == 0

Posted by Ard Biesheuvel 7 years, 1 month ago

The memory protection code may be invoked to unprotect a driver when
DxeCore has not completed loading yet, in which case ImageAddress may
still be zero. So ignore the PdbPointer in this case, to prevent
PeCoffLoaderGetPdbPointer() from ASSERT()ing on a NULL value.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
index 7689c794a8ad..6ecbb311a8c3 100644
--- a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
+++ b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
@@ -462,9 +462,12 @@ ProtectUefiImageCommon (
 
   ImageAddress = LoadedImage->ImageBase;
 
-  PdbPointer = PeCoffLoaderGetPdbPointer ((VOID*) (UINTN) ImageAddress);
-  if (PdbPointer != NULL) {
-    DEBUG ((DEBUG_VERBOSE, "  Image - %a\n", PdbPointer));
+  PdbPointer = NULL;
+  if (ImageAddress != 0) {
+    PdbPointer = PeCoffLoaderGetPdbPointer ((VOID*) (UINTN) ImageAddress);
+    if (PdbPointer != NULL) {
+      DEBUG ((DEBUG_VERBOSE, "  Image - %a\n", PdbPointer));
+    }
   }
 
   //
-- 
2.7.4

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Re: [edk2] [PATCH] MdeModulePkg/DxeCore: ignore PdbPointer if ImageAddress == 0

Posted by Gao, Liming 7 years, 1 month ago

Ard:
  On this case, UnprotectUefiImage() should be skipped, because the image is not loaded. 

Thanks
Liming
>-----Original Message-----
>From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Ard
>Biesheuvel
>Sent: Tuesday, March 21, 2017 4:45 AM
>To: edk2-devel@lists.01.org; Yao, Jiewen <jiewen.yao@intel.com>
>Cc: Tian, Feng <feng.tian@intel.com>; Zeng, Star <star.zeng@intel.com>; Ard
>Biesheuvel <ard.biesheuvel@linaro.org>
>Subject: [edk2] [PATCH] MdeModulePkg/DxeCore: ignore PdbPointer if
>ImageAddress == 0
>
>The memory protection code may be invoked to unprotect a driver when
>DxeCore has not completed loading yet, in which case ImageAddress may
>still be zero. So ignore the PdbPointer in this case, to prevent
>PeCoffLoaderGetPdbPointer() from ASSERT()ing on a NULL value.
>
>Contributed-under: TianoCore Contribution Agreement 1.0
>Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>---
> MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
>diff --git a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
>b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
>index 7689c794a8ad..6ecbb311a8c3 100644
>--- a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
>+++ b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
>@@ -462,9 +462,12 @@ ProtectUefiImageCommon (
>
>   ImageAddress = LoadedImage->ImageBase;
>
>-  PdbPointer = PeCoffLoaderGetPdbPointer ((VOID*) (UINTN)
>ImageAddress);
>-  if (PdbPointer != NULL) {
>-    DEBUG ((DEBUG_VERBOSE, "  Image - %a\n", PdbPointer));
>+  PdbPointer = NULL;
>+  if (ImageAddress != 0) {
>+    PdbPointer = PeCoffLoaderGetPdbPointer ((VOID*) (UINTN)
>ImageAddress);
>+    if (PdbPointer != NULL) {
>+      DEBUG ((DEBUG_VERBOSE, "  Image - %a\n", PdbPointer));
>+    }
>   }
>
>   //
>--
>2.7.4
>
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